Title of Invention	RADIATION CURABLE PRIMARY COATING COMPOSITION
Abstract	Abstract D1379 P RADIATION CURABLE PRIMARY COATINC ON OPTICAL FIBER Radiation curable coatings for use as a Primaiy Coating for optical fibers, optical fibers coated with said coatings and processes to coat the optical fiber are described and claimed. The radiation curable coating is a radiation curable Primary Coating composition comprising: an oligomer; a first diluent monomer; a second diluent monomer, a photoinitiator; an antioxidant; and an adhesion promoter; wherein said oligomer is the reaction product of: a hydroxyethyl acrylate; an aromatic isocyanate; an aliphatic isocyanate; a polyol; a catalyst; and an inhibitor, and wherein said oligomer has a number average molecular weight of from at least about 4000 g/mol to less than or equal to about 15,000 g/mol; wherein a cured film of said radiation curable primary coating composition has a peak tan delta Tg of from about -25 °C to about -45°C and a modulus of from about 0.50 MPa to about 1.2 MPa.

Title of Invention

RADIATION CURABLE PRIMARY COATING COMPOSITION

Abstract

Abstract D1379 P RADIATION CURABLE PRIMARY COATINC ON OPTICAL FIBER Radiation curable coatings for use as a Primaiy Coating for optical fibers, optical fibers coated with said coatings and processes to coat the optical fiber are described and claimed. The radiation curable coating is a radiation curable Primary Coating composition comprising: an oligomer; a first diluent monomer; a second diluent monomer, a photoinitiator; an antioxidant; and an adhesion promoter; wherein said oligomer is the reaction product of: a hydroxyethyl acrylate; an aromatic isocyanate; an aliphatic isocyanate; a polyol; a catalyst; and an inhibitor, and wherein said oligomer has a number average molecular weight of from at least about 4000 g/mol to less than or equal to about 15,000 g/mol; wherein a cured film of said radiation curable primary coating composition has a peak tan delta Tg of from about -25 °C to about -45°C and a modulus of from about 0.50 MPa to about 1.2 MPa.

Full Text	D1379 P RADIATION CURABLE PRIMARY COATING ON OPTICAL FIBER CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This patent application claims priority to co-pending U.S. Provisional Patent Application No. 60/874,722, "P Radiation Curable Primary Coating on Optical Fiber", filed December 14, 2006, which is incorporated herein by reference and to co-pending U.S. Provisional Patent Application No. 60/974,631, "P Radiation Curable Primary Coating on Optica! Fiber", filed September 24, 2007 which is incoiporated herein by reference. FIELD OF THE INVENTION [0002] The present invention relates to radiation curable coatings for use as a Primary Coating for optical fibers, optical fibers coated with said coalings and methods for the preparation of coated optical fibers, BACKGROUND OF THE INVENTION [0003] Optical fibers are typically coated with two or more radiation curable coatings. These coatings are typically applied to the optica] fiber in liquid form, and then exposed to radiation to effect curing. The type of radiation that may be used to cure the coatings should be that which is capable of initiating the polymerization of one or more radiation curable components of such coatings. Radiation suitable for curing such coalings is well known, and includes ultraviolet light (hereinafter "UV") and electron beam ("EB"). The preferred type of radiation for curing coatings used in the preparation of coated optical fiber is UV. [0004] The coating which directly contacts the optica! fiber is called the Primary Coating, and the coating that covers the Primary Coating is called the Secondary Coating. It is known in the art ot radiation curabie coatings for optical fibers that Primary Coatings are advantageously softer than Secondary Coatings, One advantage flowing from this arrangement is enhanced resistance to Microbends. ,. [0005] ■ Previously described Radiation Curable Coalings suitable for use as a Primary Coating for Optical Fiber include the following: [0006] Published Chinese Paleni Application No. CN1651533], "Radiation Solidification Paint and Its Application", assigned to Shanghai Feikai Photoelectric, inventors; Jibing Lin and Jinshan Zhang, describes and cJaims a radiation curable coating, comprising oligomer, active diluent, photoinitiator, thermal stabilizer, selective adhesion promoter, in which a content of the oligomer is between 20% and 70% (by weight, the following is the same), a content of the other components is between 30% and 80%; the oligomer is selected from (meth) acrylated polyurethane oligomer or a mixture of (meth) acrylated polyurelhane oligomer and (meth) acrylated epoxy oligomer; wherein said (meth) acr>'lated polyurethane oligomer is prepared by using at least the following substances: [0007] (1) one of polyols selected from polyurethane polyol, polyamide polyol, polyether polyol, polyester polyol, polycarbonate polyol, hydrocarbon polyol, polysiloxane polyol, a mixture of two or more same or different kinds of polyol (s); [0008] (2) a mixture of two or more diisocyanates or Polyisocyanates; [0009] (3) (meth) acrylated compound containing one hydroxyl capable of reacting with isocyanate. [0010] Example 3 of Published Chinese Patent Application No. CN16515331 is the only Example in this published patent application that describes the synthesis of a radiation curable coating suitable for use as a Radiation Curable Primary Coaling. The coating synthesized in Example 3 has an elastic modulus of 1.6 MPa, [0011] The article, "UV-CUKED POLYURETHANE-ACRYLIC COMPOSITIONS AS HARD EXTERNAL LAYERS OF TWO-LAYER PROTECTA^ COATINGS FOR OPTICAL FIBRES", authored by W. Podkoscielny and B. Tarasiuk. PoIim.Tworz.Wielk, Vol. 4i.Nos. 7/8, p.448-55, 1996, NDN- 131-0123-9398-2, describes studies of the optimization of synthesis of ' UV-cured urethane-acrylic oligomers and their use as hard protective coatings for optica! fibers. Polish-made oligoetherols, diethylene glycol, toluene diisocyanate (Izocyn T-80) and isophorone diisocyanate in addition to hydro>;yethy] and hydroxypropyl methacrylateswere used for the synthesis. Active diluents (butyl acrylate, 2-ethylhexyl acrylate and 1,4-butanedioI acrylate or mixtures of these) and 2,2-dimethoxy-2-phenylacetophenone as a photoinitiator were added to these urethane-acrylic oligomers which had polymerization-active double bonds. The compositions were UV-irradialed in an oxygen-free atmosphere. IR spectra of the compositions were recorded, and some physical and chemical and mechanical properties (density, molecular weight, viscosity as a function of temperature, refractive index, gel content, glass transition temperature, Shore hardness, Young's modulus, tensile strength, elongation at break, heat resistance and water vapor diffusion coefficient) were determined before and after curing. [0012] The article, "PROPERTIES OF ULTRAVIOLET CURABLE POLYURETHANE-ACRYLATES", authored by M. Koshiba; K.K.S. Hwang; S.K. Foley.; D.J. Yarusso; and S. L, Cooper; published in J.Mal.Sci., 17,No.5,May I982,p. 1447-58; NDN- 131-0063-1179-2; described a study that was made of the relationship between the chemical structure and physical properties of UV cured polyurethane-acrylates based on isophorone diisocyanate and TDI, The two systems were prepared with varying soft segment molecular weight and cross linking agent content, Dynaniic mechanical lest results showed that one- or two-phase materials might be obtained, depending on soil segment molecular weighl. As the latter increased, ihe poJyol Tg shifted to lower temperatures. Increasing using either N-vinyi pyrrolidone (NVP) or poiyethyiene glycol diacrylate (PEGDA) caused an increase in Young's modulus and ultimate tensile strength. NVP cross linking increased toughness in the two-phase materials and shifted the high temperature Tg peak to higher temperatures, but PEGDA did not have these effects. Tensile properties of the two systems were generally similar. [0013] Typically in the manufacture of radiation curable coatings for use on Optical Fiber, isocyanates are used to make urethane oligomers. In many references, including U.S. Patent No. 7,135.229, "RADIATION-CURABLE COATING COMPOSn'ION". Issued November 14, 2006, assigned to DSM DP Assets B.V., column 7, lines 10-32 the following teaching is provided to guide the person of ordinary skill in the art how to synthesize urethane oligomers: Polyisocyanates suitable for use in making compositions of the present invention can be aliphatic, cycloaliphatic or aromatic and include diisocyanates, such as 2,4-toluene diisocyanate, 2,6-to!uene diisocyanate, 1,3-xlylene diisocyanate, 1,4-xylylene diisocyanate, 1, 5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethylphenylene diisocyanate, 4,4'-biphenylene diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate, melhylenebis(4-cyclohexyl)isocyanate, 2,2,4-lrimethylhexamethylene diisocyanate, bis{2-isocyanate-ethyl)fumarate, 6-isopropyl-l,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate. lysine diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate. tetramethylxylylene diisocyanate and 2,5(Dr 6)-bis(isocyanatomethyl)-bicycio[2.2.1Iheptane. Among these diisocyanates, 2,4-toluene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, and methytenebis{4-cyclohexylisocyanate) are particularly preferred. These diisocyanate compounds are used either individually or in combination of two or more. [0014] While a number of Primary Coatings are currently available, it is desirable to provide novel Primary Coatings which have improved manufacturing and/or performance properties relative to existing coatings, SUMMARY OF THE INVENTION [0015] The first aspect of the instant claimed invention is a radiation curable Primary Coating composition comprising; A) an oligomer; B) a first diluent monomer; C) a second diluent monomer, D) a photoiniliator; E) an antioxidant; and F) an adhesion promoter; wherein said oligomer is the reaction product of: i) a hydroxyethyl acrylate; ii) . ail aromatic isocyanalc; iii) an aliphatic isocyanate; iv) a polyol; v) a catalyst; and an vi) inhibitor; and wherein said catalyst is selected from the group consisting of dibuty] tin dilaurate; metal carboxyiates, including, but not limited to: organobismuth catalysts such as bismuth neodecanoaie, CAS 34364-26-6; zinc neodecanoate, CAS 27253-29-8; zirconium neodecanoaie, CAS 39049-04-2; and zinc 2-ethylhexanoate, CAS 136-53-8; sulfonic acids, including but not limited to dodecylbenzene sulfonic acid, CAS 27176-87-0; and methane sulfonic acid, CAS 75-75-2; amino or organo-base catalysts, including, but not limited to: 1,2-dimethyliniidazole, CAS 1739-84-0; and diazab!cyclo[2.2.2]octane, CAS 280-57-9; and triphenyl phosphine; alkoxides of zirconium and titanium, including, but not limited to zirconium butoxide, (tetrabutyl zirconate) CAS 1071>76-7; and titanium butoxide, (tetrabutyl titanate) CAS 5593-70-4; and ionic liquid phosphonium, imidazolium, and pyridinium salts, such as, but not limited to, trihexyl(tetradecyl)phosphonium hexafluorophosphate, CAS No. 374683-44-0; l-butyl-3-methyiimidazoiium acetate, CAS No. 284049-75-8; and N-butyl-4-methylpyridinium chloride, CAS No. 125652-55-3; and tetradecyl(trihexyi) phosphonium; and wherein said oligomer has a number average molecular weight of from at least about 4000 g/mol to less than or equal to about 15,000 g/mol; and wherein a cured film of said radiation curable primary coating composition has a peak tan delta Tg of from about -25°C to about ~45°C and a modulus of from about 0.50 MPa to about 1.2 MPa. [0100] The second aspect of the instant claimed invention is a process for coating an optical fiber, the process comprising: a) operating a glass drawing tower to produce a glass optical fiber; and b) coating said glass optical fiber with the radiation curable Primary Coating composition of the.first aspect of the instant claimed invention; and c) contacting said radiation curable Primary Coating composition with radiation to cure the coating. The third aspect of the instant claimed invention is a process for coating an opticas fiber, the process comprising: a) operating a glass drawing tower at a line speed of between about 750 meters/minute and about 2100 meters/minute to produce a glass optical fiber; and b) coating said glass optical fiber with the radiation curable Primai'y Coating composition of the first aspect of the instant claimed invention. The fourth aspect of the instant claimed invention is a wire coated with a first and second layer, wherein the first layer is a cured radiation curable Primary Coating of the instant claimed invention that is in contact with the outer surface of the wire and the second layer is a cured commercially available Secondary Coating in contact with the outer surface of the Primary Coating, wherein the cured Primary Coating on the wire has the following properties after initial cure and after one month aging at 85"C and 85% relative humidity: A) a % RAU of from about 84% ro about 99%; B) an in-situ modulus of between about 0.15 MPa and about 0.60 MPa; and C) a Tube Tg, of from about -25'C to about -55°C. The fifth aspect of the instant claimed invention is an optical fiber coated with a first and second layer, wherein the first layer is a cured radiation curable Primary Coating of the instant claimed invention that is in contacf with the outer surface of the optical fiber and the second layer is a cured radiation curable Secondary Coating in contact with the outer surface of the Primary Coating,. wherein the cured Primary Coating on the optical fiber has the following properties after initial cure and after one month aging at S5'C and 85% relative humidity: A) a % RAU of from about 84% to about 99%>; B) an in-siiu modulus of between about 0.15 MPa and about 0.60 MPa; and C) a Tube Tg, of from about -25^C to about -55°C. [0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0017] Throaghout this patent application, the foliowing abbreviations have the indicated meanings: A-L89 7-mercaptopropyltrimethoxysilane, available from General Electric BHT 2,6-di-tert-bulyl-p-cresol, available fromFitz Chem CAS means Chemical Abstracts Registry Number DBTDL dibutyl tin dilaurate available from OMG Americas SR 504 D ethoxylated nonyl phenol, available froin Sartomer HEA hydroxyethyl acryiate, available from BASF Irganox 1035 thiodielhylene bis (3,5-dj-ten-buly]-4-hydroxyhydrocinnamate), available from Ciba P2010 polypropylene glycol (2000 MW), available from BASF IPDl isophorone diisocyanate available from Bayer TDI a mixture of 80% 2,4-ioluene diisocyanate and 20% 2,6-toluene diisocyanate, available from Bayer Pholomer 4066 ethoxylated nonolphenol acryiate, available from Cognis Irgacure 819 phenylbis(2,4,6-lrimethyl benxoyl) phosphine oxide, available from Ciba SR 306 tripropylene glycol diacrylate, available from Sartomer [0018] In one aspect, the present invention provides a radiation curable Primary Coating composition comprising; A) an oligomer; B) a first diluent monomer; C) a second diluent monomer, D) a pholoinitiaior; E) an antioxidant; and F) an adhesion promoter; wherein said oligomer is the reaction product of: i) a hydroxyethyl acrylate; ii) an aromatic isocyanate; iii) an aliphatic isocyanate; iv) apolyol; v) a catalyst; and an vi) inhibitor, and wherein said catalyst is selected i'rom the group consisting of dibuiyl tin dilaurate; metal carboxylates, including, but not limited to; organobismuth catalysts such as bismuth neodecanoate, CAS 34364-26-6; zinc neodecanoate, CAS 27253-29-8; zirconium neodecanoate, CAS 39049-04-2; and zinc 2-ethyihexanoate, CAS 136-53-8; sulfonic acids, including but not limited to dodecylbenzene sulfonic acid, CAS 27176-87-0; and methane sulfonic acid, CAS 75-75-2; amino or organo-base catalysts, including, but not limited to: 1,2-dimelhylimidazole, CAS 1739-84-0; and diazabicyclo[2.2.2]octane (DABCO), CAS 280-57-9 (strong base); and triphenyl phosphine; alkoxides of zirconium and titanium, including, but not limited to zirconium buloxide, (letrabutyl zirconate) CAS 1071-76-7; and titanium butoxide, (tetrabutyl titanate) CAS 5593-70-4; and ionic liquid phosphonium, imidazolium, and pyridinium salts, such as, but not limited to, trihcxyl(tetradecyl)phosphonium hexafluorophosphate, CAS No. 374683-44-0; l-butyi-3-methylimidazolium acetate, CAS No. 284049-75-8; and N-butyl-4-methylpyridinium chloride, CAS No. 125652-55-3; and tetradecyl(trihexyl) phosphonium; and wherein said oligomer has a number average molecular weight of from at least about 4000 g/mo! to less than or equal to about 15,000 g/mol; wherein a cured film of said radiation curable primary coating composition has a peak tan delta Tg of from about -25'C to about -45°C and a modulus of from about 0.50 MPa to about 1.2 MPa. [0019] The oligomer of the present invention is a urethane (meth)acry]aie oligomer, comprising a (meth)acryiaie group, urethane groups and a backbone. The term (meth)acrylate includes acrylates as well as methacrylate functionalities. The backbone is derived from use of a polyol which has been reacted with a diisocyanate and hydroxy alky] (meth)acrylate, preferably hydroxyethylacrylate. [0020] The oligomer is desirably prepared by reacting an acrylate (e.g., HEA) with an aromatic isocyanate (e.g., TDI) and an aliphatic isocyanate (e.g., IPD7); a polyol (e.g., P20I0); a catalyst (e.g., DBTDL); and an inhibitor (e.g.. BHT). [0021] The aromatic and aliphatic isocyanates are well known, and commercially available. A preferred aromatic isocyanate is a mixture of 80% 2,4-toluene diisocyanate and 20% 2,6-toluene diisocyanate, TDI, while a preferred aliphatic isocyanate is isophorone diisocyanate, EPDl. [0022] When preparing the oligomer, (he isocyanate component may be added to the oligomer reaction mixture in an amount ranging from about 1 to about 25 wt.%, desirably from about 1.5 to about 20 wt,%, and preferably from about 2 to about 15 wt.%, all based on the weight percent of the oligomer mixture. [0023] Desirably, the isocyanates should include more aliphatic isocyanate than aromatic isocyanate. More desirably, the ratio of aliphatic to aromatic isocyanate may range from about 2-7:1, preferably from about, 3-6:1, and most preferably from about 3-5:1. [0024] A variety of polyols may be used in the preparation of the oligomer. Examples of suitable polyols are polyether polyols, polyester polyols, polycarbonate polyols, polycaprolactone poiyois, acrylic polyols, and the like. These polyols may be used either individually or in combinations of two or more. There are no specific limitations to the manner of polymeriialion of the structural units in these polyols; any of random polymerization, block polymerization, or graft polymerization is acceptable. Preferably, P2010 (BASF) is used. [0025] When preparing the oligomer, the polyol component may be added to the oligomer reaction mixture in any suitable amount, desirably ranging from about 20 to about 80 wt.%, more desirably from about 30 to about 70 wt.%, and preferably from about 40 to about 60 wt.%, all based on the weight percent of the oligomer mixture. [0026] The number average molecular weight of the polyols suitable for use in the ' preparation of the oligomer may range from about 500 to about 8000, desirably from about 750 to about 6000, and preferably from about 1000 to about 4000, [0027] The acrylate component useful in the preparation of the oligomer may be of any suitable type, but is desirably a hydroxy alkyl (meth)acry)ate, preferably hydroxyeihylacrylate (HEA). When preparing the oligomer, the acrylate component may be added to the oligomer reaction mixture in any suitable amount, desirably from about 0.5 to about 5 wt.%, more ^ desirably from about 0.7 to about 3 wt.%, and preferably from about 1 to about 2 w.t %, all based on the weight of the oligomer reactant mixture. [0028] In the reaction which provides the oligomer, a urethanization catalyst may be used. Suitable catalysts are well known in the art, and may be one or more selected from the group consisting of dibutyl tin dilaurate (abbreviated as DBTDL); metal carboxylates, including, but not limited to; organobismuth catalysts such as bismuth neodecanoate, CAS 34364-26-6; zinc neodecanoate, CAS 27253-29-8; zirconium neodecanoate, CAS 39049-04-2, zinc 2-elhylhexanoate, CAS 136-53-8; sulfonic acids, including but not limited to dodecylbenzene sulfonic acid, CAS 27176-87-0; methane sulfonic acid, CAS 75-75-2; amino or organo-base catalysts, including, but not limited to: 1,2-dimethylimidazole, CAS 1739-84-0 (very weak base) and diazabicyclooctane (AKA DABCO), CAS 280-57-9 (strong base); triphenyl phosphine (TPP); alkoxides of zirconium and titanium, including, but not limited to Zirconium butoxide (letrabutyl zirconate) CAS 1071-76-7 and Titanium butoxide (tetrabutyl titanate) CAS 5593-70-4; and Ionic liquid phosphonium salts, Coscal 83 (an organobismuth catalyst, available from CosChem). Cyphos il 101 (tetradecyl(trihexyl) phosphonium chloride). The, preferred catalysts are DBTDL and Coscal 83. The most preferred catalyst is DBTDL. [0029] The catalysts may be used in the free, soluble, and homogeneous state, or they may be tethered to inert agents such as silica gel, or divinyl crosslinked macroreticular resins, and used in the heterogeneous state to be filtered at the conclusion of oligomer synthesis. f0030] When preparing the oligomer, the catalyst component may be added to the oligomer reaction mixture in any suitable amount, desirably from about 0.01 to about 0.1 wt.%, and more desirably from about 0.0 i to about 0.05 wt.%, all based on the weight of the oligomer reactant mixture. [0031] An inhibitor is also used in the preparation of the oligomer. This component assists in the prevention of acrylate polymerization during oligomer synthesis and storage. A number of commercialiy available inhibitors are known in the art and may be used in the preparation of the ohgomer. In an embodiment of the instant claimed invention the inhibitor is BHT. [0032] When preparing the oligomer, the inhibitor component may be added to the oligomer reaction mixture in any suitable amount, desirably from about 0.02 to about 0.2 wt.%, and more desirably from about 0,05 to about 0.10 wt,%, a)) based on the weight of the oligomer reaclant mixture, [0033] The preparation of the oligomer may be under taken by any suitable process, but preferably proceeds by mixing the isocyanates, poiyol and inhibitor components, then adding the catalyst thereto. The mixture may then be healed, and allowed to react until completion. The acrylate {e.g., HEA) may then be added, and the mixture heated until the reaction is completed. Generally, the oligomer reaction is carried out at a temperature from about ICC to about 90°C, and preferably from about 30 °C to about 85°C. [0034] An embodiment of the instant claimed invention has an oligomer which has a number average molecular weight of at least about 4000g/mol. An embodiment of the instant claimed invention has an oligomer which has a number average molecular weight of at least about 5000g/mol. An embodiment of the instant claimed invention has an oligomer which has a number average molecular weight of at least about 6000g/mol. [0035] An embodiment of the instant claimed invention has an oligomer which has a number average molecular weight of less than or equal to about 15,000g/mol. An embodiment of the instant claimed invention has an oligomer which a number average molecular weight of less than or equal to about 10,000g/mol. An embodiment of the instant claimed invention has an oligomer which has a number average moSecular weight of less than or equal to about 9000g/mol. [0036] The number average molecular weight of the Primary Coating oligomer desirably ranges from about 5000 to about 10,000, more desirably from about 6000 to about 9000, and preferably from about 7000 to about 8000. [0037] After the preparation of the oligomer, the radiation curable composition maybe prepared. The amount of the oligomer in the curable composition may vary depending on the desired properties, but will desirably range from about 20 lo about 80 wt.%, more desirably from about 30 to about 70 wt.%, and preferably from about 40 to about 60 wt.%, based on the weight percent of the radiation curable composition. [0038] A plurality of reactive monomer diluents may also be added to the curable composition; such diluents are well known in the art. A variety of diluents ai"e known in the art and may be used in the preparation of the oligomer including, without limitation, alkoxylated alkyl substituted phenol acrylate, such as ethoxylated nonyl phenol acrylate (EKPA), propoxylated nonyl phenol acrylate (PNPA), vinyl monomers such as vinyl caprolactam (nVC), isodecyl acrylate (IDA), (2-)ethyI-hexyl acrylate (EPLA), di-ethyleneglycol-ethyl-hexy!acrylate (DEGEHA), iso-bomyl acrylate (IBOA), tri-propylencglycol-diacrylate (TPGDA), hexane-diol-diacrylale (HDDA), trimethylolpropane-triacrylate (TMPTA), alkoxylated trimethylolpropane-triacrylate, and alkoxylated bisphenol A diacrylate such as ethoxylated bisphenol A diacrylate (EO-BPADA), Photomer 4066, SR 504D and SR 306. Preferably, a mixture of SR 504D and/or Photomer 4066 (first diluent) and SR 306 (second diluent) are used as the diluent component. [0039] The total amount of diluent in the curable composition may vary depending on the desired properties, but will desirably range from about 20 to about 80 wt.%, more desirably from about 30 to about 70 wt.%, and preferably from about 40 to about 60 wt.%, based on the weight percent of the radiation curable composition. The diluent component desirably includes an excess of the first diluent relative to the second diluent of about 20-80:1, and desirably from about 40-60:1. [0040] The curable composition may also desirably include one or more photoinitiators. Such components are well known in the art. When present, the photoinitiators should be included in amounts ranging from about 0.2 wt.% to about 5 wt.% of the curable composition, and preferably from about 0.5 wt.% to about 3 wt.%. A prefened photoinitiator is Ingacure 819. [0041] A further component that may be used in the curable composition is an antioxidant. Such components also are well known in the art. When present, the antioxidant component may be included in amounts ranging from about 0.1 to about 2 wt.%, and desirably from about 0.25 to about 0.75 wt.% of the curable composition. Preferably, the antioxidant is Irganox 1035. [0042] Another component desirably included in the curable composition is an adhesion promoter which, as its name implies, enhances the adhesion of the cured coating onto (he optica! fiber. Such components are well known in the art. When present, the adhesion promoter may be included in amounts ranging from about 0.2 wt. % to about 2 wt.%, desirably about 0,8 to about 1.0 wt.%, of the curable composition. Preferably, the adhesion promoter is A-189. [0043] The foregoing components may be nnixed together to provide the radiation curable coating. Desirably, the oligomer, diluent monomer, photoinitiator, and antioxidant are mixed and heated al 70°C for about 1 hour to dissolve all the powdery material. Then, the temperature is lowered to not greater than 55 "C, the adhesion promoter is added, and the components are mixed for about 30 minutes. [0044] The following examples are provided as illustrative of the instant claimed radiation curable Primary Coaling composition. AJ! amounts are calculated based on weight percent of the total radiation curable composition. [0046] The Primary Coating of the instant claimed invention is referred to as theP Primary Coating. After the Primary Coating is prepared, it may be applied directly onto the surface of the optical fiber. Drawing is carried out using either wet on dry or wet on wet mode. Wei on dry mode means the liquid Pnmary Coating is applied wet, and then radiation is applied to cure the liquid Primary Coaling to a solid layer on the wire. After the Primary Coanng is cured, the Secondary Coating is applied and then cured as well. Wet on wet mode means the liquid Primary Coating is applied wet, then the Secondary Coaling is applied wet and then both the Primary Coaling and Secondary Coalings are cured. [0047] The preferred radiation to be applied to effect the cure is Ultraviolet. : [0048] If the Secondary Coaling is clear rather than colored, a layer of ink coating may be applied thereon. If the Secondary Coaling is colored, the ink coating layer is typically not applied onto the Secondary Coating. Regardless of whether the ink coating is applied, it is common practice to place a plurality of coated fibers alongside each other in a ribbon assembly, applying a radiation curable matrix coating thereto to hold the plurality of fibers in place in that ribbon assembly. EXAMPLES Tensile Strength. Elongation, and Modulus Test Method [0049] The tensile properties (tensile strength, percent elongation at break, and modulus) of cured film samples are determined using an Instron model 4201 universal testing instrument. Samples are prepared for testing by curing a 75-pm film of the material using a Fusion UV processor. Samples are cured at 1.0 J/crn^ in a nitrogen atmosphere. Test specimens having a width of 0.5 inches and a length of 5 inches are cut from the film. The exact thickness of each specimen is measured with a micrometer. [0050] For relatively soft coatings (e.g., those with a modulus of less than about 10 MPa), the coating is drawn down and cured on a glass plate and the individual specimens cut from the glass plate with a scalpel. A 2-lb load cell is used in the Instron and modulus is calculated at 2.5% elongation with a least squares fit of the stress-strain plot. Cured films are conditioned at 23.0 + O.l'^C and 50.0 + 0.5% relative humidity for between about 16 and about 24 hours prior to testing. [0051] For relatively harder coatings, the coaling is drawn down on a Mylar film and specimens are cut with a Thwing Albert 0.5-inch precision sample cutter. A 20-lb load cell is used in the Instron and modulus is calculated at 2.5% elongation from the secant at that point. Cured films are conditioned at 23.0 + 0,1°C and 50.0 + 0.5% relative humidity for between about 16 and about 24 hours prior to testing. [0052] For testing specimens, the gage length is 2'inches and the crosshead speed is 1,00 inches/minute. All testing is done at a temperature of 23.0+0.1°C and a relative humidity of 50.0+0,5%. All measurements are determined from the average of at least 6 test specimens. DMA Test Method [0053] Dynamic Mechanic^] Analysis (DMA) is carried out on the test samples using an RSA-II instrument manufactured by Rheometric Scientific Inc. A free film specimen (typically about 36 mm long, 12 mm wide, and 0.075 mm thick) is mounted in the grips of the instrument, and the temperature initially brought to 80°C and held there for about five minutes. During the latter soak period at 80°C., the sample is stretched by about 2.5% of its original length. Also during this time, information about the sample identity, its dimensions, and the specific test method is entered into the software (RSI Orchestrator) residing on the attached personal computer. 10054] All tests are performed at a frequency of 1.0 radians, with the dynamic temperature step method having 2'C steps, a soak time of 5 to 10 seconds, an initial strain of about 0.001 (.DELTA.L/L), L is 22.4 mm in one RSA-D instrument, and with autotension and autostrain options activated. The autotension is set to ensure that the sample remained under a tensile force throughout the run, and autostrain is set to allow the strain to be increased as the sample passed through the glass transition and became softer. After the 5 minute soak time, the temperature in the sample oven is reduced in 20'C steps until the starting temperature, typically -80'C or -60'C is reached. The final temperature of the run is entered into the software before starting the run, such that the data for a sample would extend from the glassy region through the transition region and well into the rubbery region, [0055] The run is started and allowed to proceed to completion. After completion of the run, a graph of Tensile Storage Modulus ~E\ Tensile Loss Modulus = E", and tan delta, all versus temperature, appeared on the computer screen. The data points on each curve are smoothed, using a prograin in the software. On this plot, three points representing the glass transition are identified: [0056] I) The temperature at which Tensile Storage Modulus B'=1000 MPa; [0057] 2) The temperature at which Tensile Storage Modulus E'=100 MPa; [0058] 3) The temperature of the peak in the tan delta curve. If the tan delta curve contained more than one peak, the temperature of each peak is measured. One additional value obtained from the graph is the minimum value for Tensile Loss Modulus E" in the rubbery region. This value is reported as the equilibrium modulus, EQ. Measurement of Dry and Wet Adhesion [0059] Determination of dry and wet adhesion is performed using an Instron model 4201 universal testing instrument. A 75-p-m film is drawn down on a polished TLC glass plate and cured using a Fusion UV processor. Samples are cured at LO J/cm^ in a nitrogen atmosphere. [0060] The samples are conditioned at a temperature of 23 ±0.1 "C. and a relative humidity of 50 ± 0.5% for a period of 7 days. After conditioning, eight specimens are cut 6 inches long and 1 inch wide with a scalpel in the direction of the draw down, A thin layer of talc is applied to four of the specimens. The first inch of each sample is peeled back from the glass. The glass is secured to a horizonlal support on the Instron with the affixed end of the specimen adjacent to a pulley attached to the support and positioned directly underneath the crosshead. A wire is attached to the peeled-back end of the sample, run along the specimen and then run through the pulley in a direction perpendicular to the specimen. The free end of the wire is clamped in the upper jaw of the Instron, which is then activated. The test is continued until the average force value, in grams force/inch, became relatively constant. The crosshead speed is 10 in/min. Dry adhesion is the average of the four specimens. [0061] The remaining four specimens are then conditioned at 23 ±0.1°C. and a relative humidity of 95.±0.5% for 24 hours. A thin layer of a polyethylene/water slurry is applied to the surface of the specimens. Testing is then performed as in the previous paragraph. Wet adhesion is the average of the four specimens. Water Sensitivity [0062] A layer of the composition is cured to provide a UV cured coating test strip {1.5 inch.times. 1.5 inch times 0.6 mils). The test strip is weighed and placed in a vial containing deionized water, which is subsequently stored for 3 weeks at 23"C. At periodic intervals, e.g. 30 minutes, 1 hour, 2 hours, 3 hours, 6 hours,' 1 day, 2 days, 3 days, 7 days, 14 days, and 21 days, the lest strip is removed from (he vial and gently patted dry wilh a paper towel and reweighed. The percent water absorption is reported as 100(weight after immersion-weight before immersion}/(weight before immersion). The peak water absorption is the highest water absorption value reached during the 3-week immersion period. At the end of the 3-week period, the test strip is dried in a 60°C. oven for 1 hour, cooled in a desiccator for 15 minutes, and reweighed. The percent water extractables is reported as 100(weight before immersion-weight after drying)/{weight before immersion). The water sensitivity is reponed as [peak water absorptionj+jwater extractablesj. Three test strips are tested to improve the accuracy of the test. Refractive Index [0063] The refractive index of the cured compositions is determined with the Becke Line method, which entails matching the refractive index of finely cut strips of the cured composition with immersion liquids of known refraction properties. The test is performed under a microscope at 23'C and with light having a wavelength of 589 nm. Viscosity [0064] The viscosity is measured using a Physica MClO Viscometer. The lest samples are examined and if an excessive amount of bubbles is present, steps are taken to remove most of the bubbles. Not all bubbles need to be removed at this stage, because the act of sample loading introduces some bubbles. [0065] The instrument is set up for the conventional 23 system, which is used. The samples are loaded into a disposable aluminum cup by using the syringe to measure out 17 cc. The sample in the cup is examined and if it contains an excessive amount of bubbles, they are removed by a direct means such as centrifugation, or enough time is allowed to elapse to let the bubbles escape from the bulk of the liquid. Bubbles at the lop surface of the liquid ai"e acceptable. [0066] The bob is gently lowered into the liquid in the measuring cup, and the cup and bob are installed in the instrument. The sample temperature is allowed to equilibrate with the temperature of the circulating liquid by waiting five minutes. Then, the rotational speed is set to a desired value which will produce the desired sheaj-rate. The desired value of the shear rate is easily determined by one of ordinary skill in the art from an expected viscosity range of the sample. The shear rate is typically 50 sec"' or 100 sec'.The instrument panel reads out a viscosity value, and if the viscosity value varied only slightly (less than 2% relative variation) for 15 seconds, the measurement is complete. If not, it is possible that the temperature had not yet reached an equilibrium value, or that the material is changing due to shearing., If the latter case, further testing at different shear rates will be needed to define the sample's viscous properties. The results reponed are the average viscosity values of three test samples. The results are reported either in centipoises (cps) or milliPascal-seconds (mPa-s). One embodiment of a cured film of the radiaiion curable Primary Coarings of the instant claimed invention has a peak lan delta Tg of from about -25°C to about -45"C, another embodiment of a cured film of the radiation curable Primary Coatings of the instant claimed invention has a peak tan delta Tg of from about -30°C to about -40°C . One embodiment of a cured film of the radiation curable Primary Coatings of the instant claimed invention has a modulus of from about 0.50 MPa to about 1.2 MPa. Another embodiment of a cured film of the radiation curable Primary Coatings of the instant claimed invention has a modulus of from about 0.6 MPa to about 1.0 MPa. [0067] Draw Tower Simulator Discussion and Examples [0068] In the early years of optical fiber coating developments, all newly developed Primary and Secondary Coatings v^'ere first tested for their cured film properties and then submitted for evaluation on fiber drawing towers. Out of all the coatings that were requested to be drawn, it was estimated that at most 30% of them were tested on the draw tower, due to high cost and scheduling difficuities. The time from when the coating was first formulated to the time of being applied to glass fiber was typically about 6 months, which greatly slowed the product development cycle. [0069] It is known in the art of radiation cured coatings for optical fiber that when either the Primary Coating or the Secondary Coating was appHed to glass fiber, its properties often differ from the flat film properties of a cured film of the same coating. This is believed to be because the coating on fiber and the coating flat film have differences in sample size, geometry, LTV intensity exposure, acquired UV total exposure, processing speed, temperature of the substrate, curing temperature, and possibly nitrogen inerling conditions, [0070] Equipment that would provide similar curing conditions as those present at fiber manufacturers, in order to enable a more rehable coating development route and faster turnaround time has been developed. This type of alternative application and curing equipment needed to be easy to use, low maintenance, and offer reproducible performance. The name of the equipment is a "draw tower simulator" hereinafter abbreviated "DTS". Draw tower simulators are custom designed and constmcted based on detailed examination of actual glass fiber draw tower components. All the measuremenls {lamp positions, distance between coating stages, gaps between coating stages and UV lamps, etc) are duplicated from glass fiber dravv-ing towers. This helps mimic the processing conditions used in fiber drawing industry. [0071] One known DTS is equipped with five Fusion F600 lamps - two for the upper coating stage and three for the lower. The second lamp in each stage can be rotated at various angles between 15 - 135°, allowing for a more detailed study of the curing profile. [0072] The "core" used for the known DTS is 130.0±1.0 ^im stainless steel wire. Fiber drawing applicators of different designs, from different suppliers, are available for evaluation. This configuration allows the application nf optical fiber coatings at similar conditions that actually exist at industry production sites, [0,073] The draw tower simulator has already been used to expand the analysis of radiation curable coatings on optical fiber. A method of measuring the Primary Coating's in-situ modulus that can be used to indicate the coating's strength, degree of cure, and the fiber's perfomiance under different environments in 2003 was reported by P. A. M. Steeman, J.J. M. Slot, H. G. H. van Melick. A. A. F, v.d, Yen, H. Cao, and R. Johnson, in the Proceedings of the 52nd IWCS, p.246 (2003). In 2004, Steeman et al reported on how the rheological high shear profile of optical fiber coatings can be used to predict the coatings' processability at faster drawing speeds P. A. M. Steeman, W. Zoetelief, H. Cao, and M. Bulters, Proceedings of the 53rd IWCS, p. 532 (2004). The draw tower simulator can be used to investigate further the properties of Primai-y and Secondary Coatings on an optical fiber. [0074] These test methods aie useful for Primary Coalings on wire or coatings on optical fiber: [0075] Draw Tower Simulator Test Methods [0076] Percent Reacted Acrylaie Unsaturatjon for the Primary Coating abbreviated as % RAU Primary Test Method: [0077] Degree of cure on the inside Primary Coating on an optical fiber or metal wire is determined by FTIR using a diamond ATR accessory. FTIR instrument parameters include: 100 co-added scans, 4 cm"' resolution, DTGS detector, a spectrum range of 4000 - 650 cm', and an approximately 25% reduction in the default mirror velocity to improve signal-io-noise. Two spectra are required; one of the uncured liquid coating that corresponds to the coating.on the fiber or wire and one of the inner Primary Coaling on the fiber or wire. A thin film of contact cement is smeared on the center area of a 1 -inch square piece of 3-mil Mylar film. After the contact cement becomes tacky, a piece of the optical fiber or wire is placed in it. Place the sample under a low power optical microscope. The coatings on the fiber or wire are sliced through to the glass using a sharp scalpel. The coatings are then cut lengthwise down the top side of the fiber or wire for approximately 1 centimeter, making sure that the cut is clean and that the outer coating does not fold into the Primary Coating. Then the coatings are spread open onto the contact cement such that the Primary Coating next to the glass or wire is exposed as a flat film. The glass fiber or wire is broken away in the area where the Primary Coating is exposed. [0078] .The spectrum of the liquid coating is obtained after completely covering the diamond surface with the coating. The liquid should be the same batch that is used to coat the fiber or wire if possible, but the minimum requirement is that it must be the same formulation. The final format of the spectrum should be in absorbance. The exposed Primary Coating on the Myiar film IS mounted on the center of the diamond with the fiber or wire axis parallel to the direction of the infrared beam. Pressure should be put on the back of the sample to insure good contact with the crystal. The resulting spectrum should not contain any absorbances from the contact cement. If contact cement peaks are observed, a fresh sample should be prepared. It is important to run the spectrum immediately after sample preparation rather than preparing any multiple samples and running spectra when all the sample preparations are complete. The final formal of the spectrum should be in absorbance. [0079] For both the liquid and the cured coaling, measure the peak area of both the.acrylate double bond peak at 810 cm ' and a reference peak in the 750-780 cm' region. Peak area is determined using the baseline technique where a baseline is chosen to be tangent to absorbance minima on either side of the peak. The area under the peak and above the baseline is then determined. The integration limits for the liquid and the cured sample are not identical but are similar, especially for the reference peak. [0080] The ratio of the acrylate peak area lo the reference peak area is determined for boEh the liquid and the cured sample. Degree of cure, expressed as percent reacted acrylate iinsaiuration (% RAU), is calculated from the equation below: %RAU = ^^^-'^^'' where Ri, is the area ratio of the liquid sample and Rp is the area ratio of the cured Primary. In-situ Modulus of Primary Coating [0081] The in-situ modulus of a Primary Coating on a dual-coaled (soft Primary Coating and hard Secondary Coating) glass fiber or a metal wire fiber is measured by this test method. The detailed discussion on this test can be found in Sleeman, P.A.M., Slot, J.J.M., Melick, N.G.H. van, Ven, A.A.F, van de, Cao, H. &. Johnson, R. (2003). Mechanical analysis of the in-situ Primary Coating modulus test for optical fibers may be determined in accordance with (he procedure set forth in Proceedings 52nd International Wire and Cable Symposium (FWCS, -ii Philadelphia, USA, November 10-13, 2003), Paper41. [0082] For sample preparation, a short length (~2mm) of coating layer is stripped off using a stripping tool at the location - 2cm from a fiber end. The fiber is cut to form the other end with Smm exactly measured from the stripped coating edge to the fiber end. The ponion of the Smm coated fiber is then inserted into a metal sample fixture, as schematically shown in Figure 6 of the paper [1]. The coated fiber is embedded in a micro tube in the fixture; the micro lube consisted of two half cylindrical grooves; its diameter is made to be about the same as the outer diameter (~245^m) of a standard fiber. The fiber is tightly gripped after the screw is tightened; the gripping force on the Secondary Coating surface is uniform and no significant deformation occurred in the coating layer. The fixture with the fiber is then mounted on a DMA (Dynamic Mechanical Analysis) instrument: Rheometrics Solids Analyzer (RSA-TI). The metal fixture is clamped by the bottom grip. The top grip is lightened, pressing on the top portion of the coated fiber to the extent that it crushed the coating layer. The fixture and the fiber must be vertically straight. The non-embedded portion of the fiber should be controlled to a constant length for each sample; 6nim in our tests. Adjust the strain-offset to set the axial pretension to near zero {- Ig ~ Ig). [0083] Shear sandwich geometry setting is selected to measure the shear modulus G of the Primary Coating. The sample width, W, of the shear sandwich lest is entered to be 0.24mm calculated according to the following equation: wherein Rf and Rp are bare fiber and Primary Coating outer radius respectively. The geometry of a standard fiber, Rf = 62,5fam and Rp=92.5^m, is used for the calculation. The sample length of 8mm (embedded length) and thickness of 0.03mm (Primary Coating thickness) are entered in the shear sandwich geomeiry. The tests are conducted at room temperature (~23**C). The test frequency used is 1.0 radian/second. The shear strain e is set lo be 0.05. A dynamic time sweep is run to obtain 4 data points for measured shear storage modulus G. The reported G is the average of aJl data points. [0084] This measured shear modulus G is then corrected according to the correction method described in the paper [1]. The correction is to include the glass stretching into consideration in the embedded and the non-embedded pans. In the correction procedures, tensile modulus of the bare fiber (Ef) needs to be entered. For glass fibers, Ej=70GPa. For the wire fibers where stainless steel S314 wires are used, Ef=I20GPa. The corrected G value is further adjusted by using the actual Rf and Rp values. For glass fibers, fiber geometry including Rf and Rp values is measured by PK2400 Fiber Geometry System. For wire fibers, Rf is 65\|am for the 130\|j.m diameter stainless steel S314 wires used; Rp is measured under microscope. Finally, thein-situ modulus E (tensile storage modulus) for Primary Coating on fiber is calculated according toE =. 3G. The reported E is the average of three test samples. In-siru DMA for T^ measurements of Primary and Secondfirv Coatings on an optical fiber [0106] The glass transition temperatures (Tg) of Primary and Secondary Coatings on a dual-coated glass fiber or a metal wire fiber are measured by this method. These glass transition temperatures are referred to as "Tube Tg". [0107] For sample preparation, strip - 2cm length of the coating layers off the fiber as a complete coating tube from one end of the coated fiber by first dipping the coated fiber end along with,the stripping tool in liquid N2 for at least 10 seconds and then strip the coating tube off with a fast motion while the coating layers are still rigid. [0108] A DMA (Dynamic Mechanical Analysis) instrument: Rheometrics Solids Analyzer (RSA-II) is used. For RS.A-TT, the gap between the two grips of RSAD can be expanded as much as 1mm. The gap is first adjusted to the minimum level by adjusting strain offset. A simple sample holder made by a metal plate folded and lightened at the open end by a screw is used to tightly hold the coating tube sample from the lower end. Slide the fixture into the center of the lower grip and tighten the grip. Using tweezers to straighten the coating tube to upright position through the upper grip. Close and tighten the upper grip. Close the oven and set the oven temperature to a value higher than the Tg for Secondary Coating or 100°C with liquid nitrogen as temperature control medium. When the oven temperature reached that temperature, the strain offset IS adjusted until the pretension was in the range of Og to 0.3g [0109] -^^ Under the dynamic temperature step test of DMA, the test frequency is set at 1.0 radian/second; the strain is 5E-3; the temperature increment is 2'C and the soak time is 10 seconds. [0110] The geometry type is selected as cylindrical. The geometry setting was the same as the one used for secondary in-situ modulus test. The sample length is the length of the coating tube between the upper edge of the metal fixture and the lower grip, 11mm in our test. The diameter (D) is entered to be 0.16mm according to the following equation: where Rs and Rp are secondary and Primary Coating outer radius respectively. The geometry of a standard fiber, R^- 122.5}j.m and Rp=92.5jxm, is used for the calculation. [0111] A dynamic temperature step test is run from the starting temperature (100°C in our test) till the temperature below the Primary Coating Tg or -80'C. After the run, the peaks from tan 6 curve are reported as Primary Coating Tg (corresponding to the lower temperature) and Secondary Coating Tg (corresponding to the higher temperature). Note that the measured glass transition temperatures, especially for Primary glass transition temperature, should be considered as relative values of glass transition temperatures for the coating layers on fiber due to the tan 5 shift from the complex structure of the coating tube. Draw Tower Simulator Examples Various compositions of the instant claimed Primary Coating and a commercially available radiation curable Secondary Coating are applied lo wire using a Draw Tower ' Simulator. The wire is run at five different line speeds, 750 meters/minute, 1200 meters/minute, 1500 meters/minute, 1800 meters/minute and 2100 meters/minute. Drawing is carried out in wet on dry single mode, meaning the liquid Primary Coating is applied wet, the liquid Primary Coating is cured to a solid layer on the wire. Multiple runs are conducted with different compositions of the instant claimed Primary Coating and a commercially available radiation curable Secondary Coating. The cured Primary Coating on the fiber is tested for initial %RAU, initial in-situ modulus and initial Tube Tg. The coated wire is then aged for one month at 85°C and 85% relative humidity. The cured Primary Coating on the wire is then aged for one month and tested for %RAU, in-situ modulus and aged Tube Tg. Set-up conditions for the Draw Tower Simulator: -Zeidl dies are used. 899 for the T and Si05 for the 2°. -750, 1000, 1200, 1500, 1800, and 2100 m/min are the speeds. -5 lamps are used in the wet on dry process and 3 lamps are used in the wet on wet process. -(2) 600 W/in' D Fusion UV lamps are used at 100% for the 1° coalings. -C3) 600 W/in^ D Fusion UV lamps are used at 100% for the 2° coatings, -Temperatures for the two coatings are 30°C. The dies are also set to 30°C. -Carbon dioxide level is 7 liters/min at each die. -Nitrogen level is 20 iiters/min at each lamp, -Pressure for the 1° coating is 1 bar at 25 m/min and goes up to 3 bar at 1000 m/min. -Pressure for the 2° coating is 1 bar at 25 m/min and goes up to 4 bar at 1000 m/mJn. Therefore it is possible to describe and claim a wire coated with a first and second layer, wherein the first layer is a cured radiation curable Primary Coating of the instant claimed invention thai is in contact wilh the outer surface of the wire and the second layer is a cured radiation curable Secondary Coating in contact wilh the outer suiface of the Primary Coating, wherein the cured Primary Coating on the wire has the following properties afterinitial cure and after one month aging at 85°C and 85% relative hurhidity; A) a % RAU of from about 84% to about 99%; B) an in-situ modulus of between about 0.15 MPa and about 0.60 MPa; and C) a Tube Tg, of from about -25°C to about -55°C. Using this information it is possible to describe and claim an optical fiber coated with a first and second layer, wherein the first layer is a cured radiation curable Primary Coating of the instant claimed invention that is in contact with the outer surface of the optical fiber and the second layer is a cured radiation curable Secondary Coating in contact with the outer surface of the Primary Coating, wherein the cured Primary Coating on the fiber has the following properties after initial cure and after one month aging at 85'C and 85% relative humidity: A) a % RAU of from about 84% to about 99%; B) an in-siiu modulus of between about 0.15 MPa and about 0.60 MPa; and C) a Tube Tg, of from about -25°C to about -55°C. [0086] The radiadon curable Secondary Coating may be any commercially available radiation curable Secondary Coating for optica! fiber. Such commercially available radiation curable Secondary Coalings are available from DSM Desotech Inc., and others, including, but without being limited to Hexion, Luvanlix and PhiChem. [0087] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. [0088] The use of the terms 'a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of refeiTing individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise cletirly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. [0089] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description, The inventors expect skilled anisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. WHAT IS CLAIMED IS: [0090] 1. A radiation curable Primary Coating composition comprising: A) an oligomer; B) a first diluent monomer; C) a second diluent monomer, D) a photoinitiator; E) an antioxidant; and F) an adhesion promoter; wherein said oligomer is the reaction product of: i) a hydroxyethyl acrylate; ii) an aromatic isocyanate; iii) an aliphatic isocyanate; iv) apolyol; v) a catalyst; and an vi) inhibitor, and wherein said oligomer has a number average molecular weight of from at least about ■■1000 g,'mo! to less than or equal to about 15,000 g/mol; wnd wherein said catalyst is selected from the group consisting of dibutyl tin dilaurate; metal carboxylates, including, but not limited to: organobismuth catalysts such as bismuth neodecanoate, CAS 34364-26-6; zinc neodecanoate, CAS 27253-29-8; zirconium neodecanoatc, CAS 39049-04-2; and zinc 2-ethylhexanoate, CAS 136-53-8; sulfonic acids, including but not limited to dodecylbenzene sulfonic acid, CAS 27176-87-0; and methane sulfonic acid, CAS 75- 75-2; amino or organo-base catalysts, including, but not limited to: l,2-dimethy!imida2ole, CAS 1739-84^0; and diazabicycjo[2.2.2]octane (DABCO), CAS 280-57-9 (strong base); and triphenyl phosphine; aikoxides of zirconium and titanium, including, but not limited to zirconium butoxide, (telrabulyl zirconate) CAS 1071-76-7; and titanium butoxide. (telrabutyl titanate) CAS 5593-70-4; and ionic liquid phosphonium, imidazolium, and pyridinium salts, such as, but not limited to. trihexyl(tetradecyI)phosphonium hexafluorophosphate, CAS No. 374683-44-0; l-buty]-3-methylimida20lium acetate, CAS No. 284049-75-8; and N-butyl-4-methylpyridinium chloride, CAS No. 125652-55-3; and tetradecyl(trihexy!) phosphonium; and wherein a cured film of said radiation curable primary coating composition has apeak tan delta Tg of from about -25°C to about -45°C and a modulus of from about 0.50 MPa to about 1.2 MPa. [0112] 2. A process for coating an optical fiber, the process comprising: a) operating a glass drawing tower to produce a glass optical fiber; and b) coating said glass optical fiber with the radiation curable Primary Coating composition of Claim 1. 3. The process of Claim 2 in which said glass drawing tower is operated at a line speed of between about 750meters/minute and about 2100 meters/minute 4. A wire coated with a first and second layer, wherein the first layer is a cured radiation curable Primary Coating of Claim 1 that is in contact with the outer surface of the wire and the second layer is a cured radiation curable Secondary Coating in contact with the outer surface of the Primary Coating, wherein the cured Primary Coating on the wire has the following properties after initial cure and after one month aging at SS-C and 85% relative humidity; A) a % RAU of from about 84% to about 99%; B) an in-situ modulus of between about 0.15 MPa and about 0.60 MPa; ^nd C) a Tube Tg, of from about -aS^C to about -SS^C. 5. An optical fiber coated with a first and second layer, wherein the first layer is a cured radiation curable Primary Coaling of Claim 1 that is in conlaci with the outer surface of the optical fiber and the second layer is a cured radiation curable Secondary Coating in contact with the outer surface of the Primary Coating, wherein the cured Primary Coating on the optica! fiber has the following properties after initial cure and after one month aging at SS'C and 85% relative humidity: A) a % RAU of from about 84% to about 99%; B) an in-situ modulus of between about 0.15 MPa and about 0.60 MPa; and; C) a Tube Tg, of from about -25°C to about -55°C. 6. The radiation curable composition of Claim 1 in which the catalyst is selected from the group consisting of dibutyl tin dilaurate and organobismuth catalysts such as bismuth neodecanoate; zinc neodecanoate; zirconium neodecanoate; zinc 2-elhylhexanoate; and tetradecylCtrihexyl) phosphonium chloride. 7. The radiation curable composition of Claim 6 in which the catalyst is dibutyl tin dilaurate.

Full Text

D1379 P RADIATION CURABLE PRIMARY COATING ON OPTICAL FIBER
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application claims priority to co-pending U.S. Provisional Patent Application No. 60/874,722, "P Radiation Curable Primary Coating on Optical Fiber", filed December 14, 2006, which is incorporated herein by reference and to co-pending U.S. Provisional Patent Application No. 60/974,631, "P Radiation Curable Primary Coating on Optica! Fiber", filed September 24, 2007 which is incoiporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to radiation curable coatings for use as a Primary Coating for optical fibers, optical fibers coated with said coalings and methods for the preparation of coated optical fibers,
BACKGROUND OF THE INVENTION
[0003] Optical fibers are typically coated with two or more radiation curable coatings. These coatings are typically applied to the optica] fiber in liquid form, and then exposed to radiation to effect curing. The type of radiation that may be used to cure the coatings should be that which is capable of initiating the polymerization of one or more radiation curable components of such coatings. Radiation suitable for curing such coalings is well known, and includes ultraviolet light (hereinafter "UV") and electron beam ("EB"). The preferred type of radiation for curing coatings used in the preparation of coated optical fiber is UV.
[0004] The coating which directly contacts the optica! fiber is called the Primary Coating, and the coating that covers the Primary Coating is called the Secondary Coating. It is known in

the art ot radiation curabie coatings for optical fibers that Primary Coatings are advantageously
softer than Secondary Coatings, One advantage flowing from this arrangement is enhanced
resistance to Microbends. ,.
[0005] ■ Previously described Radiation Curable Coalings suitable for use as a Primary
Coating for Optical Fiber include the following:
[0006] Published Chinese Paleni Application No. CN1651533], "Radiation Solidification
Paint and Its Application", assigned to Shanghai Feikai Photoelectric, inventors; Jibing Lin and
Jinshan Zhang, describes and cJaims a radiation curable coating, comprising oligomer, active
diluent, photoinitiator, thermal stabilizer, selective adhesion promoter, in which a content of the
oligomer is between 20% and 70% (by weight, the following is the same), a content of the other
components is between 30% and 80%; the oligomer is selected from (meth) acrylated
polyurethane oligomer or a mixture of (meth) acrylated polyurelhane oligomer and (meth)
acrylated epoxy oligomer; wherein said (meth) acr>'lated polyurethane oligomer is prepared by
using at least the following substances:
[0007] (1) one of polyols selected from polyurethane polyol, polyamide polyol, polyether
polyol, polyester polyol, polycarbonate polyol, hydrocarbon polyol, polysiloxane polyol, a
mixture of two or more same or different kinds of polyol (s);
[0008] (2) a mixture of two or more diisocyanates or Polyisocyanates;
[0009] (3) (meth) acrylated compound containing one hydroxyl capable of reacting with
isocyanate.
[0010] Example 3 of Published Chinese Patent Application No. CN16515331 is the only
Example in this published patent application that describes the synthesis of a radiation curable

coating suitable for use as a Radiation Curable Primary Coaling. The coating synthesized in Example 3 has an elastic modulus of 1.6 MPa,
[0011] The article, "UV-CUKED POLYURETHANE-ACRYLIC COMPOSITIONS AS HARD EXTERNAL LAYERS OF TWO-LAYER PROTECTA^ COATINGS FOR OPTICAL FIBRES", authored by W. Podkoscielny and B. Tarasiuk. PoIim.Tworz.Wielk, Vol. 4i.Nos. 7/8, p.448-55, 1996, NDN- 131-0123-9398-2, describes studies of the optimization of synthesis of ' UV-cured urethane-acrylic oligomers and their use as hard protective coatings for optica! fibers. Polish-made oligoetherols, diethylene glycol, toluene diisocyanate (Izocyn T-80) and isophorone diisocyanate in addition to hydro>;yethy] and hydroxypropyl methacrylateswere used for the synthesis. Active diluents (butyl acrylate, 2-ethylhexyl acrylate and 1,4-butanedioI acrylate or mixtures of these) and 2,2-dimethoxy-2-phenylacetophenone as a photoinitiator were added to these urethane-acrylic oligomers which had polymerization-active double bonds. The compositions were UV-irradialed in an oxygen-free atmosphere. IR spectra of the compositions were recorded, and some physical and chemical and mechanical properties (density, molecular weight, viscosity as a function of temperature, refractive index, gel content, glass transition temperature, Shore hardness, Young's modulus, tensile strength, elongation at break, heat resistance and water vapor diffusion coefficient) were determined before and after curing. [0012] The article, "PROPERTIES OF ULTRAVIOLET CURABLE POLYURETHANE-ACRYLATES", authored by M. Koshiba; K.K.S. Hwang; S.K. Foley.; D.J. Yarusso; and S. L, Cooper; published in J.Mal.Sci., 17,No.5,May I982,p. 1447-58; NDN- 131-0063-1179-2; described a study that was made of the relationship between the chemical structure and physical properties of UV cured polyurethane-acrylates based on isophorone diisocyanate and TDI, The two systems were prepared with varying soft segment molecular weight and cross linking agent

content, Dynaniic mechanical lest results showed that one- or two-phase materials might be obtained, depending on soil segment molecular weighl. As the latter increased, ihe poJyol Tg shifted to lower temperatures. Increasing using either N-vinyi pyrrolidone (NVP) or poiyethyiene glycol diacrylate (PEGDA) caused an increase in Young's modulus and ultimate tensile strength. NVP cross linking increased toughness in the two-phase materials and shifted the high temperature Tg peak to higher temperatures, but PEGDA did not have these effects. Tensile properties of the two systems were generally similar.
[0013] Typically in the manufacture of radiation curable coatings for use on Optical Fiber, isocyanates are used to make urethane oligomers. In many references, including U.S. Patent No. 7,135.229, "RADIATION-CURABLE COATING COMPOSn'ION". Issued November 14, 2006, assigned to DSM DP Assets B.V., column 7, lines 10-32 the following teaching is provided to guide the person of ordinary skill in the art how to synthesize urethane oligomers: Polyisocyanates suitable for use in making compositions of the present invention can be aliphatic, cycloaliphatic or aromatic and include diisocyanates, such as 2,4-toluene diisocyanate, 2,6-to!uene diisocyanate, 1,3-xlylene diisocyanate, 1,4-xylylene diisocyanate, 1, 5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethylphenylene diisocyanate, 4,4'-biphenylene diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate, melhylenebis(4-cyclohexyl)isocyanate, 2,2,4-lrimethylhexamethylene diisocyanate, bis{2-isocyanate-ethyl)fumarate, 6-isopropyl-l,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate. lysine diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate. tetramethylxylylene diisocyanate and 2,5(Dr 6)-bis(isocyanatomethyl)-bicycio[2.2.1Iheptane. Among these diisocyanates, 2,4-toluene diisocyanate, isophorone

diisocyanate, xylylene diisocyanate, and methytenebis{4-cyclohexylisocyanate) are particularly preferred. These diisocyanate compounds are used either individually or in combination of two or more.
[0014] While a number of Primary Coatings are currently available, it is desirable to provide novel Primary Coatings which have improved manufacturing and/or performance properties relative to existing coatings,
SUMMARY OF THE INVENTION
[0015] The first aspect of the instant claimed invention is a radiation curable Primary Coating composition comprising;
A) an oligomer;
B) a first diluent monomer;
C) a second diluent monomer,
D) a photoiniliator;
E) an antioxidant; and
F) an adhesion promoter;
wherein said oligomer is the reaction product of:
i) a hydroxyethyl acrylate;
ii) . ail aromatic isocyanalc;
iii) an aliphatic isocyanate;
iv) a polyol;
v) a catalyst; and an
vi) inhibitor; and

wherein said catalyst is selected from the group consisting of dibuty] tin dilaurate; metal carboxyiates, including, but not limited to: organobismuth catalysts such as bismuth neodecanoaie, CAS 34364-26-6; zinc neodecanoate, CAS 27253-29-8; zirconium neodecanoaie, CAS 39049-04-2; and zinc 2-ethylhexanoate, CAS 136-53-8; sulfonic acids, including but not limited to dodecylbenzene sulfonic acid, CAS 27176-87-0; and methane sulfonic acid, CAS 75-75-2; amino or organo-base catalysts, including, but not limited to: 1,2-dimethyliniidazole, CAS 1739-84-0; and diazab!cyclo[2.2.2]octane, CAS 280-57-9; and triphenyl phosphine; alkoxides of zirconium and titanium, including, but not limited to zirconium butoxide, (tetrabutyl zirconate) CAS 1071>76-7; and titanium butoxide, (tetrabutyl titanate) CAS 5593-70-4; and ionic liquid phosphonium, imidazolium, and pyridinium salts, such as, but not limited to, trihexyl(tetradecyl)phosphonium hexafluorophosphate, CAS No. 374683-44-0; l-butyl-3-methyiimidazoiium acetate, CAS No. 284049-75-8; and N-butyl-4-methylpyridinium chloride, CAS No. 125652-55-3; and tetradecyl(trihexyi) phosphonium; and
wherein said oligomer has a number average molecular weight of from at least about 4000 g/mol to less than or equal to about 15,000 g/mol; and
wherein a cured film of said radiation curable primary coating composition has a peak tan delta Tg of from about -25°C to about ~45°C and a modulus of from about 0.50 MPa to about 1.2 MPa.
[0100] The second aspect of the instant claimed invention is a process for coating an optical fiber, the process comprising:
a) operating a glass drawing tower to produce a glass optical fiber; and

b) coating said glass optical fiber with the radiation curable Primary Coating composition of the.first aspect of the instant claimed invention; and
c) contacting said radiation curable Primary Coating composition with radiation to cure the coating.
The third aspect of the instant claimed invention is a process for coating an opticas fiber, the process comprising:
a) operating a glass drawing tower at a line speed of between about 750
meters/minute and about 2100 meters/minute to produce a glass optical fiber; and
b) coating said glass optical fiber with the radiation curable Primai'y Coating
composition of the first aspect of the instant claimed invention.
The fourth aspect of the instant claimed invention is a wire coated with a first and second layer, wherein the first layer is a cured radiation curable Primary Coating of the instant claimed invention that is in contact with the outer surface of the wire and the second layer is a cured commercially available Secondary Coating in contact with the outer surface of the Primary Coating,
wherein the cured Primary Coating on the wire has the following properties after initial cure and after one month aging at 85"C and 85% relative humidity:
A) a % RAU of from about 84% ro about 99%;
B) an in-situ modulus of between about 0.15 MPa and about 0.60 MPa; and
C) a Tube Tg, of from about -25'C to about -55°C.

The fifth aspect of the instant claimed invention is an optical fiber coated with a first and second layer, wherein the first layer is a cured radiation curable Primary Coating of the instant claimed invention that is in contacf with the outer surface of the optical fiber and the second layer is a cured radiation curable Secondary Coating in contact with the outer surface of the Primary Coating,.
wherein the cured Primary Coating on the optical fiber has the following properties after initial cure and after one month aging at S5'C and 85% relative humidity:
A) a % RAU of from about 84% to about 99%>;
B) an in-siiu modulus of between about 0.15 MPa and about 0.60 MPa; and
C) a Tube Tg, of from about -25^C to about -55°C. [0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] Throaghout this patent application, the foliowing abbreviations have the indicated meanings:

A-L89 7-mercaptopropyltrimethoxysilane, available from General Electric
BHT 2,6-di-tert-bulyl-p-cresol, available fromFitz Chem
CAS means Chemical Abstracts Registry Number
DBTDL dibutyl tin dilaurate available from OMG Americas
SR 504 D ethoxylated nonyl phenol, available froin Sartomer
HEA hydroxyethyl acryiate, available from BASF
Irganox 1035 thiodielhylene bis (3,5-dj-ten-buly]-4-hydroxyhydrocinnamate), available from Ciba
P2010 polypropylene glycol (2000 MW), available from BASF
IPDl isophorone diisocyanate available from Bayer
TDI a mixture of 80% 2,4-ioluene diisocyanate and 20% 2,6-toluene diisocyanate, available from Bayer
Pholomer 4066 ethoxylated nonolphenol acryiate, available from Cognis
Irgacure 819 phenylbis(2,4,6-lrimethyl benxoyl) phosphine oxide, available from Ciba
SR 306 tripropylene glycol diacrylate, available from Sartomer
[0018] In one aspect, the present invention provides a radiation curable Primary Coating composition comprising;
A) an oligomer;
B) a first diluent monomer;
C) a second diluent monomer,
D) a pholoinitiaior;

E) an antioxidant; and
F) an adhesion promoter;
wherein said oligomer is the reaction product of:
i) a hydroxyethyl acrylate;
ii) an aromatic isocyanate;
iii) an aliphatic isocyanate;
iv) apolyol;
v) a catalyst; and an
vi) inhibitor, and
wherein said catalyst is selected i'rom the group consisting of dibuiyl tin dilaurate; metal carboxylates, including, but not limited to; organobismuth catalysts such as bismuth neodecanoate, CAS 34364-26-6; zinc neodecanoate, CAS 27253-29-8; zirconium neodecanoate, CAS 39049-04-2; and zinc 2-ethyihexanoate, CAS 136-53-8; sulfonic acids, including but not limited to dodecylbenzene sulfonic acid, CAS 27176-87-0; and methane sulfonic acid, CAS 75-75-2; amino or organo-base catalysts, including, but not limited to: 1,2-dimelhylimidazole, CAS 1739-84-0; and diazabicyclo[2.2.2]octane (DABCO), CAS 280-57-9 (strong base); and triphenyl phosphine; alkoxides of zirconium and titanium, including, but not limited to zirconium buloxide, (letrabutyl zirconate) CAS 1071-76-7; and titanium butoxide, (tetrabutyl titanate) CAS 5593-70-4; and ionic liquid phosphonium, imidazolium, and pyridinium salts, such as, but not limited to, trihcxyl(tetradecyl)phosphonium hexafluorophosphate, CAS No. 374683-44-0; l-butyi-3-methylimidazolium acetate, CAS No. 284049-75-8; and N-butyl-4-methylpyridinium chloride, CAS No. 125652-55-3; and tetradecyl(trihexyl) phosphonium; and

wherein said oligomer has a number average molecular weight of from at least about 4000 g/mo! to less than or equal to about 15,000 g/mol;
wherein a cured film of said radiation curable primary coating composition has a peak tan delta Tg of from about -25'C to about -45°C and a modulus of from about 0.50 MPa to about 1.2 MPa.
[0019] The oligomer of the present invention is a urethane (meth)acry]aie oligomer, comprising a (meth)acryiaie group, urethane groups and a backbone. The term (meth)acrylate includes acrylates as well as methacrylate functionalities. The backbone is derived from use of a polyol which has been reacted with a diisocyanate and hydroxy alky] (meth)acrylate, preferably hydroxyethylacrylate.
[0020] The oligomer is desirably prepared by reacting an acrylate (e.g., HEA) with an aromatic isocyanate (e.g., TDI) and an aliphatic isocyanate (e.g., IPD7); a polyol (e.g., P20I0); a catalyst (e.g., DBTDL); and an inhibitor (e.g.. BHT).
[0021] The aromatic and aliphatic isocyanates are well known, and commercially available. A preferred aromatic isocyanate is a mixture of 80% 2,4-toluene diisocyanate and 20% 2,6-toluene diisocyanate, TDI, while a preferred aliphatic isocyanate is isophorone diisocyanate, EPDl.
[0022] When preparing the oligomer, (he isocyanate component may be added to the oligomer reaction mixture in an amount ranging from about 1 to about 25 wt.%, desirably from about 1.5 to about 20 wt,%, and preferably from about 2 to about 15 wt.%, all based on the weight percent of the oligomer mixture.

[0023] Desirably, the isocyanates should include more aliphatic isocyanate than aromatic isocyanate. More desirably, the ratio of aliphatic to aromatic isocyanate may range from about 2-7:1, preferably from about, 3-6:1, and most preferably from about 3-5:1. [0024] A variety of polyols may be used in the preparation of the oligomer. Examples of suitable polyols are polyether polyols, polyester polyols, polycarbonate polyols, polycaprolactone poiyois, acrylic polyols, and the like. These polyols may be used either individually or in combinations of two or more. There are no specific limitations to the manner of polymeriialion of the structural units in these polyols; any of random polymerization, block polymerization, or graft polymerization is acceptable. Preferably, P2010 (BASF) is used. [0025] When preparing the oligomer, the polyol component may be added to the oligomer reaction mixture in any suitable amount, desirably ranging from about 20 to about 80 wt.%, more desirably from about 30 to about 70 wt.%, and preferably from about 40 to about 60 wt.%, all based on the weight percent of the oligomer mixture.
[0026] The number average molecular weight of the polyols suitable for use in the ' preparation of the oligomer may range from about 500 to about 8000, desirably from about 750 to about 6000, and preferably from about 1000 to about 4000,
[0027] The acrylate component useful in the preparation of the oligomer may be of any suitable type, but is desirably a hydroxy alkyl (meth)acry)ate, preferably hydroxyeihylacrylate (HEA). When preparing the oligomer, the acrylate component may be added to the oligomer reaction mixture in any suitable amount, desirably from about 0.5 to about 5 wt.%, more ^ desirably from about 0.7 to about 3 wt.%, and preferably from about 1 to about 2 w.t %, all based on the weight of the oligomer reactant mixture.

[0028] In the reaction which provides the oligomer, a urethanization catalyst may be used. Suitable catalysts are well known in the art, and may be one or more selected from the group consisting of dibutyl tin dilaurate (abbreviated as DBTDL); metal carboxylates, including, but not limited to; organobismuth catalysts such as bismuth neodecanoate, CAS 34364-26-6; zinc neodecanoate, CAS 27253-29-8; zirconium neodecanoate, CAS 39049-04-2, zinc 2-elhylhexanoate, CAS 136-53-8; sulfonic acids, including but not limited to dodecylbenzene sulfonic acid, CAS 27176-87-0; methane sulfonic acid, CAS 75-75-2; amino or organo-base catalysts, including, but not limited to: 1,2-dimethylimidazole, CAS 1739-84-0 (very weak base) and diazabicyclooctane (AKA DABCO), CAS 280-57-9 (strong base); triphenyl phosphine (TPP); alkoxides of zirconium and titanium, including, but not limited to Zirconium butoxide (letrabutyl zirconate) CAS 1071-76-7 and Titanium butoxide (tetrabutyl titanate) CAS 5593-70-4; and Ionic liquid phosphonium salts, Coscal 83 (an organobismuth catalyst, available from CosChem). Cyphos il 101 (tetradecyl(trihexyl) phosphonium chloride). The, preferred catalysts are DBTDL and Coscal 83. The most preferred catalyst is DBTDL.
[0029] The catalysts may be used in the free, soluble, and homogeneous state, or they may be tethered to inert agents such as silica gel, or divinyl crosslinked macroreticular resins, and used in the heterogeneous state to be filtered at the conclusion of oligomer synthesis. f0030] When preparing the oligomer, the catalyst component may be added to the oligomer reaction mixture in any suitable amount, desirably from about 0.01 to about 0.1 wt.%, and more desirably from about 0.0 i to about 0.05 wt.%, all based on the weight of the oligomer reactant mixture.
[0031] An inhibitor is also used in the preparation of the oligomer. This component assists in the prevention of acrylate polymerization during oligomer synthesis and storage. A number of

commercialiy available inhibitors are known in the art and may be used in the preparation of the
ohgomer. In an embodiment of the instant claimed invention the inhibitor is BHT.
[0032] When preparing the oligomer, the inhibitor component may be added to the oligomer
reaction mixture in any suitable amount, desirably from about 0.02 to about 0.2 wt.%, and more
desirably from about 0,05 to about 0.10 wt,%, a)) based on the weight of the oligomer reaclant
mixture,
[0033] The preparation of the oligomer may be under taken by any suitable process, but
preferably proceeds by mixing the isocyanates, poiyol and inhibitor components, then adding the
catalyst thereto. The mixture may then be healed, and allowed to react until completion. The
acrylate {e.g., HEA) may then be added, and the mixture heated until the reaction is completed.
Generally, the oligomer reaction is carried out at a temperature from about ICC to about 90°C,
and preferably from about 30 °C to about 85°C.
[0034] An embodiment of the instant claimed invention has an oligomer which has a number
average molecular weight of at least about 4000g/mol. An embodiment of the instant claimed
invention has an oligomer which has a number average molecular weight of at least about
5000g/mol. An embodiment of the instant claimed invention has an oligomer which has a
number average molecular weight of at least about 6000g/mol.
[0035] An embodiment of the instant claimed invention has an oligomer which has a number
average molecular weight of less than or equal to about 15,000g/mol. An embodiment of the
instant claimed invention has an oligomer which a number average molecular weight of less than
or equal to about 10,000g/mol. An embodiment of the instant claimed invention has an oligomer
which has a number average moSecular weight of less than or equal to about 9000g/mol.

[0036] The number average molecular weight of the Primary Coating oligomer desirably ranges from about 5000 to about 10,000, more desirably from about 6000 to about 9000, and preferably from about 7000 to about 8000.
[0037] After the preparation of the oligomer, the radiation curable composition maybe prepared. The amount of the oligomer in the curable composition may vary depending on the desired properties, but will desirably range from about 20 lo about 80 wt.%, more desirably from about 30 to about 70 wt.%, and preferably from about 40 to about 60 wt.%, based on the weight percent of the radiation curable composition.
[0038] A plurality of reactive monomer diluents may also be added to the curable composition; such diluents are well known in the art. A variety of diluents ai"e known in the art and may be used in the preparation of the oligomer including, without limitation, alkoxylated alkyl substituted phenol acrylate, such as ethoxylated nonyl phenol acrylate (EKPA), propoxylated nonyl phenol acrylate (PNPA), vinyl monomers such as vinyl caprolactam (nVC), isodecyl acrylate (IDA), (2-)ethyI-hexyl acrylate (EPLA), di-ethyleneglycol-ethyl-hexy!acrylate (DEGEHA), iso-bomyl acrylate (IBOA), tri-propylencglycol-diacrylate (TPGDA), hexane-diol-diacrylale (HDDA), trimethylolpropane-triacrylate (TMPTA), alkoxylated trimethylolpropane-triacrylate, and alkoxylated bisphenol A diacrylate such as ethoxylated bisphenol A diacrylate (EO-BPADA), Photomer 4066, SR 504D and SR 306. Preferably, a mixture of SR 504D and/or Photomer 4066 (first diluent) and SR 306 (second diluent) are used as the diluent component. [0039] The total amount of diluent in the curable composition may vary depending on the desired properties, but will desirably range from about 20 to about 80 wt.%, more desirably from about 30 to about 70 wt.%, and preferably from about 40 to about 60 wt.%, based on the weight percent of the radiation curable composition. The diluent component desirably includes an

excess of the first diluent relative to the second diluent of about 20-80:1, and desirably from about 40-60:1.
[0040] The curable composition may also desirably include one or more photoinitiators. Such components are well known in the art. When present, the photoinitiators should be included in amounts ranging from about 0.2 wt.% to about 5 wt.% of the curable composition, and preferably from about 0.5 wt.% to about 3 wt.%. A prefened photoinitiator is Ingacure 819. [0041] A further component that may be used in the curable composition is an antioxidant. Such components also are well known in the art. When present, the antioxidant component may be included in amounts ranging from about 0.1 to about 2 wt.%, and desirably from about 0.25 to about 0.75 wt.% of the curable composition. Preferably, the antioxidant is Irganox 1035. [0042] Another component desirably included in the curable composition is an adhesion promoter which, as its name implies, enhances the adhesion of the cured coating onto (he optica! fiber. Such components are well known in the art. When present, the adhesion promoter may be included in amounts ranging from about 0.2 wt. % to about 2 wt.%, desirably about 0,8 to about 1.0 wt.%, of the curable composition. Preferably, the adhesion promoter is A-189. [0043] The foregoing components may be nnixed together to provide the radiation curable coating. Desirably, the oligomer, diluent monomer, photoinitiator, and antioxidant are mixed and heated al 70°C for about 1 hour to dissolve all the powdery material. Then, the temperature is lowered to not greater than 55 "C, the adhesion promoter is added, and the components are mixed for about 30 minutes.

[0044] The following examples are provided as illustrative of the instant claimed radiation curable Primary Coaling composition. AJ! amounts are calculated based on weight percent of the total radiation curable composition.

[0046] The Primary Coating of the instant claimed invention is referred to as theP
Primary Coating.
After the Primary Coating is prepared, it may be applied directly onto the surface of the
optical fiber. Drawing is carried out using either wet on dry or wet on wet mode. Wei on dry
mode means the liquid Pnmary Coating is applied wet, and then radiation is applied to cure the
liquid Primary Coaling to a solid layer on the wire. After the Primary Coanng is cured, the
Secondary Coating is applied and then cured as well. Wet on wet mode means the liquid Primary
Coating is applied wet, then the Secondary Coaling is applied wet and then both the Primary
Coaling and Secondary Coalings are cured.
[0047] The preferred radiation to be applied to effect the cure is Ultraviolet. :
[0048] If the Secondary Coaling is clear rather than colored, a layer of ink coating may be
applied thereon. If the Secondary Coaling is colored, the ink coating layer is typically not
applied onto the Secondary Coating. Regardless of whether the ink coating is applied, it is
common practice to place a plurality of coated fibers alongside each other in a ribbon assembly,
applying a radiation curable matrix coating thereto to hold the plurality of fibers in place in that
ribbon assembly.
EXAMPLES
Tensile Strength. Elongation, and Modulus Test Method
[0049] The tensile properties (tensile strength, percent elongation at break, and modulus) of cured film samples are determined using an Instron model 4201 universal testing instrument. Samples are prepared for testing by curing a 75-pm film of the material using a Fusion UV processor. Samples are cured at 1.0 J/crn^ in a nitrogen atmosphere. Test specimens having a width of 0.5 inches and a length of 5 inches are cut from the film. The exact thickness of each specimen is measured with a micrometer.

[0050] For relatively soft coatings (e.g., those with a modulus of less than about 10 MPa), the coating is drawn down and cured on a glass plate and the individual specimens cut from the glass plate with a scalpel. A 2-lb load cell is used in the Instron and modulus is calculated at 2.5% elongation with a least squares fit of the stress-strain plot. Cured films are conditioned at 23.0 + O.l'^C and 50.0 + 0.5% relative humidity for between about 16 and about 24 hours prior to testing.
[0051] For relatively harder coatings, the coaling is drawn down on a Mylar film and specimens are cut with a Thwing Albert 0.5-inch precision sample cutter. A 20-lb load cell is used in the Instron and modulus is calculated at 2.5% elongation from the secant at that point. Cured films are conditioned at 23.0 + 0,1°C and 50.0 + 0.5% relative humidity for between about 16 and about 24 hours prior to testing.
[0052] For testing specimens, the gage length is 2'inches and the crosshead speed is 1,00 inches/minute. All testing is done at a temperature of 23.0+0.1°C and a relative humidity of 50.0+0,5%. All measurements are determined from the average of at least 6 test specimens.
DMA Test Method
[0053] Dynamic Mechanic^] Analysis (DMA) is carried out on the test samples using an RSA-II instrument manufactured by Rheometric Scientific Inc. A free film specimen (typically about 36 mm long, 12 mm wide, and 0.075 mm thick) is mounted in the grips of the instrument, and the temperature initially brought to 80°C and held there for about five minutes. During the latter soak period at 80°C., the sample is stretched by about 2.5% of its original length. Also during this time, information about the sample identity, its dimensions, and the specific test method is entered into the software (RSI Orchestrator) residing on the attached personal computer.
10054] All tests are performed at a frequency of 1.0 radians, with the dynamic temperature step method having 2'C steps, a soak time of 5 to 10 seconds, an initial strain of about 0.001 (.DELTA.L/L), L is 22.4 mm in one RSA-D instrument, and with autotension and autostrain options activated. The autotension is set to ensure that the sample remained under a tensile force throughout the run, and autostrain is set to allow the strain to be increased as the sample passed through the glass transition and became softer. After the 5 minute soak time, the temperature in the sample oven is reduced in 20'C steps until the starting temperature, typically -80*'C or -60'*C

is reached. The final temperature of the run is entered into the software before starting the run,
such that the data for a sample would extend from the glassy region through the transition region
and well into the rubbery region,
[0055] The run is started and allowed to proceed to completion. After completion of the run,
a graph of Tensile Storage Modulus ~E\ Tensile Loss Modulus = E", and tan delta, all versus
temperature, appeared on the computer screen. The data points on each curve are smoothed,
using a prograin in the software. On this plot, three points representing the glass transition are
identified:
[0056] I) The temperature at which Tensile Storage Modulus B'=1000 MPa;
[0057] 2) The temperature at which Tensile Storage Modulus E'=100 MPa;
[0058] 3) The temperature of the peak in the tan delta curve. If the tan delta curve contained
more than one peak, the temperature of each peak is measured. One additional value obtained
from the graph is the minimum value for Tensile Loss Modulus E" in the rubbery region. This
value is reported as the equilibrium modulus, EQ.
Measurement of Dry and Wet Adhesion
[0059] Determination of dry and wet adhesion is performed using an Instron model 4201 universal testing instrument. A 75-p-m film is drawn down on a polished TLC glass plate and cured using a Fusion UV processor. Samples are cured at LO J/cm^ in a nitrogen atmosphere. [0060] The samples are conditioned at a temperature of 23 ±0.1 "C. and a relative humidity of 50 ± 0.5% for a period of 7 days. After conditioning, eight specimens are cut 6 inches long and 1 inch wide with a scalpel in the direction of the draw down, A thin layer of talc is applied to four of the specimens. The first inch of each sample is peeled back from the glass. The glass is secured to a horizonlal support on the Instron with the affixed end of the specimen adjacent to a pulley attached to the support and positioned directly underneath the crosshead. A wire is attached to the peeled-back end of the sample, run along the specimen and then run through the pulley in a direction perpendicular to the specimen. The free end of the wire is clamped in the upper jaw of the Instron, which is then activated. The test is continued until the average force value, in grams force/inch, became relatively constant. The crosshead speed is 10 in/min. Dry adhesion is the average of the four specimens.

[0061] The remaining four specimens are then conditioned at 23 ±0.1°C. and a relative humidity of 95.±0.5% for 24 hours. A thin layer of a polyethylene/water slurry is applied to the surface of the specimens. Testing is then performed as in the previous paragraph. Wet adhesion is the average of the four specimens. Water Sensitivity
[0062] A layer of the composition is cured to provide a UV cured coating test strip {1.5 inch.times. 1.5 inch times 0.6 mils). The test strip is weighed and placed in a vial containing deionized water, which is subsequently stored for 3 weeks at 23"C. At periodic intervals, e.g. 30 minutes, 1 hour, 2 hours, 3 hours, 6 hours,' 1 day, 2 days, 3 days, 7 days, 14 days, and 21 days, the lest strip is removed from (he vial and gently patted dry wilh a paper towel and reweighed. The percent water absorption is reported as 100*(weight after immersion-weight before immersion}/(weight before immersion). The peak water absorption is the highest water absorption value reached during the 3-week immersion period. At the end of the 3-week period, the test strip is dried in a 60°C. oven for 1 hour, cooled in a desiccator for 15 minutes, and reweighed. The percent water extractables is reported as 100*(weight before immersion-weight after drying)/{weight before immersion). The water sensitivity is reponed as [peak water absorptionj+jwater extractablesj. Three test strips are tested to improve the accuracy of the test.
Refractive Index
[0063] The refractive index of the cured compositions is determined with the Becke Line method, which entails matching the refractive index of finely cut strips of the cured composition with immersion liquids of known refraction properties. The test is performed under a microscope at 23'C and with light having a wavelength of 589 nm.
Viscosity
[0064] The viscosity is measured using a Physica MClO Viscometer. The lest samples are examined and if an excessive amount of bubbles is present, steps are taken to remove most of the bubbles. Not all bubbles need to be removed at this stage, because the act of sample loading introduces some bubbles.
[0065] The instrument is set up for the conventional 23 system, which is used. The samples are loaded into a disposable aluminum cup by using the syringe to measure out 17 cc. The

sample in the cup is examined and if it contains an excessive amount of bubbles, they are removed by a direct means such as centrifugation, or enough time is allowed to elapse to let the bubbles escape from the bulk of the liquid. Bubbles at the lop surface of the liquid ai"e acceptable.
[0066] The bob is gently lowered into the liquid in the measuring cup, and the cup and bob are installed in the instrument. The sample temperature is allowed to equilibrate with the temperature of the circulating liquid by waiting five minutes. Then, the rotational speed is set to a desired value which will produce the desired sheaj-rate. The desired value of the shear rate is easily determined by one of ordinary skill in the art from an expected viscosity range of the sample. The shear rate is typically 50 sec"' or 100 sec'.The instrument panel reads out a viscosity value, and if the viscosity value varied only slightly (less than 2% relative variation) for 15 seconds, the measurement is complete. If not, it is possible that the temperature had not yet reached an equilibrium value, or that the material is changing due to shearing., If the latter case, further testing at different shear rates will be needed to define the sample's viscous properties. The results reponed are the average viscosity values of three test samples. The results are reported either in centipoises (cps) or milliPascal-seconds (mPa-s).

One embodiment of a cured film of the radiaiion curable Primary Coarings of the instant claimed invention has a peak lan delta Tg of from about -25°C to about -45"C, another embodiment of a cured film of the radiation curable Primary Coatings of the instant claimed invention has a peak tan delta Tg of from about -30°C to about -40°C .
One embodiment of a cured film of the radiation curable Primary Coatings of the instant claimed invention has a modulus of from about 0.50 MPa to about 1.2 MPa. Another embodiment of a cured film of the radiation curable Primary Coatings of the instant claimed invention has a modulus of from about 0.6 MPa to about 1.0 MPa.
[0067] Draw Tower Simulator Discussion and Examples
[0068] In the early years of optical fiber coating developments, all newly developed Primary and Secondary Coatings v^'ere first tested for their cured film properties and then submitted for evaluation on fiber drawing towers. Out of all the coatings that were requested to be drawn, it was estimated that at most 30% of them were tested on the draw tower, due to high cost and scheduling difficuities. The time from when the coating was first formulated to the time of being applied to glass fiber was typically about 6 months, which greatly slowed the product development cycle.
[0069] It is known in the art of radiation cured coatings for optical fiber that when either the Primary Coating or the Secondary Coating was appHed to glass fiber, its properties often differ from the flat film properties of a cured film of the same coating. This is believed to be because the coating on fiber and the coating flat film have differences in sample size, geometry, LTV

intensity exposure, acquired UV total exposure, processing speed, temperature of the substrate,
curing temperature, and possibly nitrogen inerling conditions,
[0070] Equipment that would provide similar curing conditions as those present at fiber
manufacturers, in order to enable a more rehable coating development route and faster
turnaround time has been developed. This type of alternative application and curing equipment
needed to be easy to use, low maintenance, and offer reproducible performance. The name of
the equipment is a "draw tower simulator" hereinafter abbreviated "DTS". Draw tower
simulators are custom designed and constmcted based on detailed examination of actual glass
fiber draw tower components. All the measuremenls {lamp positions, distance between coating
stages, gaps between coating stages and UV lamps, etc) are duplicated from glass fiber dravv-ing
towers. This helps mimic the processing conditions used in fiber drawing industry.
[0071] One known DTS is equipped with five Fusion F600 lamps - two for the upper coating
stage and three for the lower. The second lamp in each stage can be rotated at various angles
between 15 - 135°, allowing for a more detailed study of the curing profile.
[0072] The "core" used for the known DTS is 130.0±1.0 ^im stainless steel wire. Fiber
drawing applicators of different designs, from different suppliers, are available for evaluation.
This configuration allows the application nf optical fiber coatings at similar conditions that
actually exist at industry production sites,
[0,073] The draw tower simulator has already been used to expand the analysis of radiation
curable coatings on optical fiber. A method of measuring the Primary Coating's in-situ modulus
that can be used to indicate the coating's strength, degree of cure, and the fiber's perfomiance
under different environments in 2003 was reported by P. A. M. Steeman, J.J. M. Slot, H. G. H.

van Melick. A. A. F, v.d, Yen, H. Cao, and R. Johnson, in the Proceedings of the 52nd IWCS,
p.246 (2003). In 2004, Steeman et al reported on how the rheological high shear profile of
optical fiber coatings can be used to predict the coatings' processability at faster drawing speeds
P. A. M. Steeman, W. Zoetelief, H. Cao, and M. Bulters, Proceedings of the 53rd IWCS, p. 532
(2004). The draw tower simulator can be used to investigate further the properties of Primai-y
and Secondary Coatings on an optical fiber.
[0074] These test methods aie useful for Primary Coalings on wire or coatings on optical
fiber:
[0075] Draw Tower Simulator Test Methods
[0076] Percent Reacted Acrylaie Unsaturatjon for the Primary Coating abbreviated as %
RAU Primary Test Method:
[0077] Degree of cure on the inside Primary Coating on an optical fiber or metal wire is
determined by FTIR using a diamond ATR accessory. FTIR instrument parameters include: 100
co-added scans, 4 cm"' resolution, DTGS detector, a spectrum range of 4000 - 650 cm', and an
approximately 25% reduction in the default mirror velocity to improve signal-io-noise. Two
spectra are required; one of the uncured liquid coating that corresponds to the coating.on the
fiber or wire and one of the inner Primary Coaling on the fiber or wire. A thin film of contact
cement is smeared on the center area of a 1 -inch square piece of 3-mil Mylar film. After the
contact cement becomes tacky, a piece of the optical fiber or wire is placed in it. Place the
sample under a low power optical microscope. The coatings on the fiber or wire are sliced
through to the glass using a sharp scalpel. The coatings are then cut lengthwise down the top
side of the fiber or wire for approximately 1 centimeter, making sure that the cut is clean and that

the outer coating does not fold into the Primary Coating. Then the coatings are spread open onto the contact cement such that the Primary Coating next to the glass or wire is exposed as a flat film. The glass fiber or wire is broken away in the area where the Primary Coating is exposed. [0078] .The spectrum of the liquid coating is obtained after completely covering the diamond surface with the coating. The liquid should be the same batch that is used to coat the fiber or wire if possible, but the minimum requirement is that it must be the same formulation. The final format of the spectrum should be in absorbance. The exposed Primary Coating on the Myiar film IS mounted on the center of the diamond with the fiber or wire axis parallel to the direction of the infrared beam. Pressure should be put on the back of the sample to insure good contact with the crystal. The resulting spectrum should not contain any absorbances from the contact cement. If contact cement peaks are observed, a fresh sample should be prepared. It is important to run the spectrum immediately after sample preparation rather than preparing any multiple samples and running spectra when all the sample preparations are complete. The final formal of the spectrum should be in absorbance.
[0079] For both the liquid and the cured coaling, measure the peak area of both the.acrylate double bond peak at 810 cm ' and a reference peak in the 750-780 cm' region. Peak area is determined using the baseline technique where a baseline is chosen to be tangent to absorbance minima on either side of the peak. The area under the peak and above the baseline is then determined. The integration limits for the liquid and the cured sample are not identical but are similar, especially for the reference peak.

[0080] The ratio of the acrylate peak area lo the reference peak area is determined for boEh the liquid and the cured sample. Degree of cure, expressed as percent reacted acrylate iinsaiuration (% RAU), is calculated from the equation below:
%RAU = ^^^-'^^''
where Ri, is the area ratio of the liquid sample and Rp is the area ratio of the cured Primary.
In-situ Modulus of Primary Coating
[0081] The in-situ modulus of a Primary Coating on a dual-coaled (soft Primary Coating and hard Secondary Coating) glass fiber or a metal wire fiber is measured by this test method. The detailed discussion on this test can be found in Sleeman, P.A.M., Slot, J.J.M., Melick, N.G.H. van, Ven, A.A.F, van de, Cao, H. &. Johnson, R. (2003). Mechanical analysis of the in-situ Primary Coating modulus test for optical fibers may be determined in accordance with (he procedure set forth in Proceedings 52nd International Wire and Cable Symposium (FWCS,
-ii
Philadelphia, USA, November 10-13, 2003), Paper41.
[0082] For sample preparation, a short length (~2mm) of coating layer is stripped off using a stripping tool at the location - 2cm from a fiber end. The fiber is cut to form the other end with Smm exactly measured from the stripped coating edge to the fiber end. The ponion of the Smm coated fiber is then inserted into a metal sample fixture, as schematically shown in Figure 6 of the paper [1]. The coated fiber is embedded in a micro tube in the fixture; the micro lube consisted of two half cylindrical grooves; its diameter is made to be about the same as the outer diameter (~245^m) of a standard fiber. The fiber is tightly gripped after the screw is tightened; the gripping force on the Secondary Coating surface is uniform and no significant deformation

occurred in the coating layer. The fixture with the fiber is then mounted on a DMA (Dynamic Mechanical Analysis) instrument: Rheometrics Solids Analyzer (RSA-TI). The metal fixture is clamped by the bottom grip. The top grip is lightened, pressing on the top portion of the coated fiber to the extent that it crushed the coating layer. The fixture and the fiber must be vertically straight. The non-embedded portion of the fiber should be controlled to a constant length for each sample; 6nim in our tests. Adjust the strain-offset to set the axial pretension to near zero {-
Ig ~ Ig).
[0083] Shear sandwich geometry setting is selected to measure the shear modulus G of the Primary Coating. The sample width, W, of the shear sandwich lest is entered to be 0.24mm calculated according to the following equation:
wherein Rf and Rp are bare fiber and Primary Coating outer radius respectively. The geometry of a standard fiber, Rf = 62,5fam and Rp=92.5^m, is used for the calculation. The sample length of 8mm (embedded length) and thickness of 0.03mm (Primary Coating thickness) are entered in the shear sandwich geomeiry. The tests are conducted at room temperature (~23**C). The test frequency used is 1.0 radian/second. The shear strain e is set lo be 0.05. A dynamic time sweep is run to obtain 4 data points for measured shear storage modulus G. The reported G is the average of aJl data points.
[0084] This measured shear modulus G is then corrected according to the correction method described in the paper [1]. The correction is to include the glass stretching into consideration in the embedded and the non-embedded pans. In the correction procedures, tensile modulus of the

bare fiber (Ef) needs to be entered. For glass fibers, Ej=70GPa. For the wire fibers where stainless steel S314 wires are used, Ef=I20GPa. The corrected G value is further adjusted by using the actual Rf and Rp values. For glass fibers, fiber geometry including Rf and Rp values is measured by PK2400 Fiber Geometry System. For wire fibers, Rf is 65|am for the 130|j.m diameter stainless steel S314 wires used; Rp is measured under microscope. Finally, thein-situ modulus E (tensile storage modulus) for Primary Coating on fiber is calculated according toE =. 3G. The reported E is the average of three test samples.
In-siru DMA for T^ measurements of Primary and Secondfirv Coatings on an optical fiber [0106] The glass transition temperatures (Tg) of Primary and Secondary Coatings on a dual-coated glass fiber or a metal wire fiber are measured by this method. These glass transition temperatures are referred to as "Tube Tg".
[0107] For sample preparation, strip - 2cm length of the coating layers off the fiber as a complete coating tube from one end of the coated fiber by first dipping the coated fiber end along with,the stripping tool in liquid N2 for at least 10 seconds and then strip the coating tube off with a fast motion while the coating layers are still rigid.
[0108] A DMA (Dynamic Mechanical Analysis) instrument: Rheometrics Solids Analyzer (RSA-II) is used. For RS.A-TT, the gap between the two grips of RSAD can be expanded as much as 1mm. The gap is first adjusted to the minimum level by adjusting strain offset. A simple sample holder made by a metal plate folded and lightened at the open end by a screw is used to tightly hold the coating tube sample from the lower end. Slide the fixture into the center of the lower grip and tighten the grip. Using tweezers to straighten the coating tube to upright position through the upper grip. Close and tighten the upper grip. Close the oven and set the oven

temperature to a value higher than the Tg for Secondary Coating or 100°C with liquid nitrogen
as temperature control medium. When the oven temperature reached that temperature, the strain
offset IS adjusted until the pretension was in the range of Og to 0.3g
[0109] -^^ Under the dynamic temperature step test of DMA, the test frequency is set at 1.0
radian/second; the strain is 5E-3; the temperature increment is 2'C and the soak time is 10
seconds.
[0110] The geometry type is selected as cylindrical. The geometry setting was the same as
the one used for secondary in-situ modulus test. The sample length is the length of the coating
tube between the upper edge of the metal fixture and the lower grip, 11mm in our test. The
diameter (D) is entered to be 0.16mm according to the following equation:
where Rs and Rp are secondary and Primary Coating outer radius respectively. The geometry of a standard fiber, R^- 122.5}j.m and Rp=92.5jxm, is used for the calculation. [0111] A dynamic temperature step test is run from the starting temperature (100°C in our test) till the temperature below the Primary Coating Tg or -80'C. After the run, the peaks from tan 6 curve are reported as Primary Coating Tg (corresponding to the lower temperature) and Secondary Coating Tg (corresponding to the higher temperature). Note that the measured glass transition temperatures, especially for Primary glass transition temperature, should be considered as relative values of glass transition temperatures for the coating layers on fiber due to the tan 5 shift from the complex structure of the coating tube. Draw Tower Simulator Examples

Various compositions of the instant claimed Primary Coating and a commercially available radiation curable Secondary Coating are applied lo wire using a Draw Tower ' Simulator. The wire is run at five different line speeds, 750 meters/minute, 1200 meters/minute, 1500 meters/minute, 1800 meters/minute and 2100 meters/minute. Drawing is carried out in wet on dry single mode, meaning the liquid Primary Coating is applied wet, the liquid Primary Coating is cured to a solid layer on the wire.
Multiple runs are conducted with different compositions of the instant claimed Primary Coating and a commercially available radiation curable Secondary Coating. The cured Primary Coating on the fiber is tested for initial %RAU, initial in-situ modulus and initial Tube Tg. The coated wire is then aged for one month at 85°C and 85% relative humidity. The cured Primary Coating on the wire is then aged for one month and tested for %RAU, in-situ modulus and aged Tube Tg.
Set-up conditions for the Draw Tower Simulator: -Zeidl dies are used. 899 for the T and Si05 for the 2°. -750, 1000, 1200, 1500, 1800, and 2100 m/min are the speeds. -5 lamps are used in the wet on dry process and 3 lamps are used in the wet on wet process.
-(2) 600 W/in' D Fusion UV lamps are used at 100% for the 1° coalings.
-C3) 600 W/in^ D Fusion UV lamps are used at 100% for the 2° coatings, -Temperatures for the two coatings are 30°C. The dies are also set to 30°C. -Carbon dioxide level is 7 liters/min at each die. -Nitrogen level is 20 iiters/min at each lamp, -Pressure for the 1° coating is 1 bar at 25 m/min and goes up to 3 bar at 1000 m/min.

-Pressure for the 2° coating is 1 bar at 25 m/min and goes up to 4 bar at 1000 m/mJn.

Therefore it is possible to describe and claim a wire coated with a first and second layer, wherein the first layer is a cured radiation curable Primary Coating of the instant claimed

invention thai is in contact wilh the outer surface of the wire and the second layer is a cured radiation curable Secondary Coating in contact wilh the outer suiface of the Primary Coating, wherein the cured Primary Coating on the wire has the following properties afterinitial cure and after one month aging at 85°C and 85% relative hurhidity;
A) a % RAU of from about 84% to about 99%;
B) an in-situ modulus of between about 0.15 MPa and about 0.60 MPa; and
C) a Tube Tg, of from about -25°C to about -55°C.
Using this information it is possible to describe and claim an optical fiber coated with a first and second layer, wherein the first layer is a cured radiation curable Primary Coating of the instant claimed invention that is in contact with the outer surface of the optical fiber and the second layer is a cured radiation curable Secondary Coating in contact with the outer surface of the Primary Coating,
wherein the cured Primary Coating on the fiber has the following properties after initial cure and after one month aging at 85'C and 85% relative humidity:
A) a % RAU of from about 84% to about 99%;
B) an in-siiu modulus of between about 0.15 MPa and about 0.60 MPa; and
C) a Tube Tg, of from about -25°C to about -55°C.
[0086] The radiadon curable Secondary Coating may be any commercially available radiation curable Secondary Coating for optica! fiber. Such commercially available radiation curable Secondary Coalings are available from DSM Desotech Inc., and others, including, but without being limited to Hexion, Luvanlix and PhiChem.

[0087] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. [0088] The use of the terms 'a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of refeiTing individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise cletirly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
[0089] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description, The inventors expect skilled anisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as

specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

WHAT IS CLAIMED IS:
[0090] 1. A radiation curable Primary Coating composition comprising:
A) an oligomer;
B) a first diluent monomer;
C) a second diluent monomer,
D) a photoinitiator;
E) an antioxidant; and
F) an adhesion promoter;
wherein said oligomer is the reaction product of:
i) a hydroxyethyl acrylate;
ii) an aromatic isocyanate;
iii) an aliphatic isocyanate;
iv) apolyol;
v) a catalyst; and an
vi) inhibitor, and
wherein said oligomer has a number average molecular weight of from at least about ■■1000 g,'mo! to less than or equal to about 15,000 g/mol; wnd
wherein said catalyst is selected from the group consisting of dibutyl tin dilaurate; metal carboxylates, including, but not limited to: organobismuth catalysts such as bismuth neodecanoate, CAS 34364-26-6; zinc neodecanoate, CAS 27253-29-8; zirconium neodecanoatc, CAS 39049-04-2; and zinc 2-ethylhexanoate, CAS 136-53-8; sulfonic acids, including but not limited to dodecylbenzene sulfonic acid, CAS 27176-87-0; and methane sulfonic acid, CAS 75-

75-2; amino or organo-base catalysts, including, but not limited to: l,2-dimethy!imida2ole, CAS 1739-84^0; and diazabicycjo[2.2.2]octane (DABCO), CAS 280-57-9 (strong base); and triphenyl phosphine; aikoxides of zirconium and titanium, including, but not limited to zirconium butoxide, (telrabulyl zirconate) CAS 1071-76-7; and titanium butoxide. (telrabutyl titanate) CAS 5593-70-4; and ionic liquid phosphonium, imidazolium, and pyridinium salts, such as, but not limited to. trihexyl(tetradecyI)phosphonium hexafluorophosphate, CAS No. 374683-44-0; l-buty]-3-methylimida20lium acetate, CAS No. 284049-75-8; and N-butyl-4-methylpyridinium chloride, CAS No. 125652-55-3; and tetradecyl(trihexy!) phosphonium; and
wherein a cured film of said radiation curable primary coating composition has apeak tan delta Tg of from about -25°C to about -45°C and a modulus of from about 0.50 MPa to about 1.2 MPa.
[0112] 2. A process for coating an optical fiber, the process comprising:
a) operating a glass drawing tower to produce a glass optical fiber; and
b) coating said glass optical fiber with the radiation curable Primary Coating
composition of Claim 1.
3. The process of Claim 2 in which said glass drawing tower is operated at a line speed
of between about 750meters/minute and about 2100 meters/minute
4. A wire coated with a first and second layer, wherein the first layer is a cured
radiation curable Primary Coating of Claim 1 that is in contact with the outer surface of the wire
and the second layer is a cured radiation curable Secondary Coating in contact with the outer
surface of the Primary Coating,

wherein the cured Primary Coating on the wire has the following properties after initial cure and after one month aging at SS-C and 85% relative humidity;
A) a % RAU of from about 84% to about 99%;
B) an in-situ modulus of between about 0.15 MPa and about 0.60 MPa; ^nd
C) a Tube Tg, of from about -aS^C to about -SS^C.
5. An optical fiber coated with a first and second layer, wherein the first layer is a
cured radiation curable Primary Coaling of Claim 1 that is in conlaci with the outer surface of the
optical fiber and the second layer is a cured radiation curable Secondary Coating in contact with
the outer surface of the Primary Coating,
wherein the cured Primary Coating on the optica! fiber has the following properties after initial cure and after one month aging at SS'C and 85% relative humidity:
A) a % RAU of from about 84% to about 99%;
B) an in-situ modulus of between about 0.15 MPa and about 0.60 MPa; and;
C) a Tube Tg, of from about -25°C to about -55°C.

6. The radiation curable composition of Claim 1 in which the catalyst is selected from the group consisting of dibutyl tin dilaurate and organobismuth catalysts such as bismuth neodecanoate; zinc neodecanoate; zirconium neodecanoate; zinc 2-elhylhexanoate; and tetradecylCtrihexyl) phosphonium chloride.
7. The radiation curable composition of Claim 6 in which the catalyst is dibutyl tin dilaurate.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=UsUUfuPaPR0sflARd7GORg==&loc=egcICQiyoj82NGgGrC5ChA==

« Previous Patent

Next Patent »

Patent Number

280059

Indian Patent Application Number

2578/CHENP/2009

PG Journal Number

06/2017

Publication Date

10-Feb-2017

Grant Date

08-Feb-2017

Date of Filing

07-May-2009

Name of Patentee

DSM IP ASSETS B.V.

Applicant Address

HET OVERLOON 1, 6411 TE HHERLEN,

Inventors:

#	Inventor's Name	Inventor's Address
1	ZIMMERMAN, JOHN, M.,	1616 BIRMINGHAM LANE, CRYSTAL LAKE, IL 60014
2	MURPHY, EDWARD, J.,	742 S.MITCHELL AVENUE, ARLINGTON HEIGHTS, IL 60005
3	TORTORELLO, ANTHONY, JOSEPH,	449 E.EAST CT., ELMHURST, IL 60126
4	WU, XIAOSONG,	9928 EMPIRE WOODS CT., CHARLOTTE, NC 2827
5	SCHMID, STEVEN, R.,	446 ROSLYN ROAD, EAST DUNDEE, IL 60118

PCT International Classification Number

C03C 25/10

PCT International Application Number

PCT/US07/25482

PCT International Filing date

2007-12-13

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	60/974,631	2007-09-24	U.S.A.
2	60/874,722	2006-12-14	U.S.A.