Title of Invention	AN INK JET PRINTING PAPER PRODUCT HAVING APPLIED TO ITS SURFACE AN INK JET COATING FORMULATION".
Abstract	In one embodiment of the invention, a network system includes a boundary router, a second router, and an upstream link of the second router coupled between to the output port of the boundary router and an input port of the second router. The second router includes an admission control function and a data plane. In response to a request to reserve resources for a flow through the second router, the admission control function performs admission control for both the upstream link and its downstream link. In a preferred embodiment, the second router performs admission control for the upstream link only if the second router is a receiving edge router for the flow. Because the second router performs admission control for its upstream link, the boundary router transmits the request toward an upstream router without performing admission control for the link Fig. Nil

Title of Invention

AN INK JET PRINTING PAPER PRODUCT HAVING APPLIED TO ITS SURFACE AN INK JET COATING FORMULATION".

Abstract

In one embodiment of the invention, a network system includes a boundary router, a second router, and an upstream link of the second router coupled between to the output port of the boundary router and an input port of the second router. The second router includes an admission control function and a data plane. In response to a request to reserve resources for a flow through the second router, the admission control function performs admission control for both the upstream link and its downstream link. In a preferred embodiment, the second router performs admission control for the upstream link only if the second router is a receiving edge router for the flow. Because the second router performs admission control for its upstream link, the boundary router transmits the request toward an upstream router without performing admission control for the link Fig. Nil

Full Text	INK JET PRINTING PAPER INCORPORATING AMINE FUNCTIONAL POLY(VINYL ALCOHOL) Technical Field This invention relates to paper products having a unique coaling thereon rendering them well suited for use with ink jet printers. Background of the Invention Advances in ink jet printing technology. ha\e placed new demands on the printed paper and paper coatings. To function properly the printed substrate must quickly absorb the ink and ink vehicles directly after printing, maximize the ink optical density, minimize ink bleed and wicking. and provide a means of making the inks waterfast. Ink Jet coatings generally comprise silica pigment having a high absorption capability and a polymeric binder such as a polyi vinyl alcohol) binder having a high binding strength. A variety of additives have been utilized to improve coating properties. Cationic additives, for example, have been added to help with ink waterfastness and lightfastness. Other variations in the ink jet coating formulations include the use of non silica pigments such as ciays. aluminum hvdrate. calcium carbonate, titanium dioxide, magnesium carbonate and the use of binders such as stvrene-butadiene. polyvinyl pyrrolidone. polyvinyl acetate, acrylic binders, and starch. The following patents and articles are representative of various resins and ink jet paper coatings. US 4.818.341 discloses the addition of a cationic polymer e.g. hydroiyzed vinyl acetate or vinyl propionate N-vinyl formamide copolymers to paper stock to enhance the dry-strength in all tvpes of paper and paper board, e.g.. writing paper and packaging papers. The polymers are added in an amount of from 35-1 50 grams per square meter for paper and up to 600 grams per square meter for paper board. US 4.880.197 discloses the addition of water-soluble copolymers containing polymerized vinvl amine units, e.g.. a hydrolyzed vinyl acetate N-vinyl formamide copolymer to paper stock prior to sheet formation in an amount of from 0.1-50%. based on cry fiber. Japanese-laid open Kokai application 5-28323 discloses a recording sheet having good ink absorptivity, image quality and excellent water resistance which comprises a dye fixing layer and ink adsorption layer laminated thereon. One of the principal components of the dye fixing layer applied to the recording sheet is a cation modified polyvinyl alcohol. Cation modified polyvinyl alcohols are characterized as hydrolyzed copolymers of viny1 acetate and ethylenically unsaiurated monomers having quaternary ammonium salt groups. The content of the cationic group is from 0.1 -10) mole percent An abstract, of Japanese 63162276A2 discloses an image acceptor for ink jet recordings. The image acceptor includes silica pretreated with water soluble resins either on the recording surface or within the acceptor. A solution of sodium silicate and sulfuric acid is mixed with 5% of a cation modified polyvim I alcohol and applied to a paper sheet and then an ink applied t hereto. Japanese Patent 05139023 discloses an aqueous based ink jet coating comprising silica pigment and a fully hydrolyzed. medium molecular weight poly (viny1 alcohol) coating. This coating is applied to a paper support at coat weights of 0.7 to O.8g/cm2 to provide high color quality images with good dot shape. German patent 514633 Al 921125 describes an ink jet coating which contains 50% silica pigment. 40% poly(vinyl alcohol) having a hydrolysis value of 92.5%. and 10% of a cationic polyacrylamide. When applied to a paper substrate at a coating weight of 10 grams/m2 this coating provides excellent color density;. and small dot diameter? yielding excellent print fidelity. Japanese patent 01186372 A2 890725 describes the addition of polyacrylamide to an ink iet coating comprising silica pigment and fully hydrolyzed low molecular weight poly ( vinyl alcohel ) This coating yield good smudge resistance and hghttastness. Japanese patent 06247036 A2 940906 discloses the use of a cationic polyethl leneimine quatemar} ammonium salt in combination with silica pigment and fully hydrolyzed low molecuiar weight poly (vinyl alcohol) as an ink jet receiving iayer. Japanese patent 61134291 A2 S60621 discloses a cationic PYOH binder for use in an ink let coating the binder used is a saponified tnmethyl-3-( l-acry)amidopropyhammonium". chloride - v inyl acetate copolymer with a percent hydrolysis of 98.5 and a cationic content of 3 moie % and :: degree of polymerization of 1 750. Coatings using this binder with silica pigment provide excellent print fidelity and good water resistance to paper. US 5.405.678 discloses an ink jet paper having a substrate coated with a non coalesced latex film comprised of a hydrophobic polymer. e.g.. ethylene-vinyl chloride copolymers. acrylic latexe. sillca, and disnersants. US 5.270. 103 discloses receiver sheets suited for printing with aqueous based inks, such as those used in ink jet printing systems. The coaling formulation is comprised of a pigment a:xl a binder consisting of polyvinyl alcohol and another polymer. e.g.. eationic polyvinyl alcohol and poly(vinyl pyrrolidone). US 6.096.826 discloses the synthesis of a amine functional polyvinyl alcohol via the reaction piperidone with poiy(v inyl alcohol) particles. The end product was found 10 be useful as a mordant/binder for ink jet coated papers. US 6.096.440 discloses the use of an ink jet recording medium having an ink receiving !ayer composed of hydrophilie resin, a block copolymer of poly viny1 alcohol and a hydrophobie polymer. US -440 further discusses the use of a cationic-modified poly (vinyl alcohol). Kurray CM-318. produced by Kuraray Co. Ltd. as a binder for the ink jet receiving lyer. Summary of the Invention This invention relates to an improvement in paper products having an aqueous based ink jet coating applied to its surface. The improvement generally resides in the incorporation of an a primary amine functional polyvinyl alcohol (PVOH PVNH2) as a polymeric binder in the ink jet coating. One form of an amine functional polyvinyl alcohol is produced by the hydrolysis of a copoiymer of vinyl acetate and N-vinylfotmamide (PVOH PVNH2). another formed by the polymerization of vinyl acetate and ailyl amine. and another is the 4-aminobutyral derivative of polyvinyl alcohol. Several advantages are associated with the paper products incorporating the improved ink jet coating. These advantages include: the incorporation of a primary amine functional poiyvinyl alcohol as a polymer binder in the ink jet coating eases the makedown procedure of the coating formulation by eliminating the need to add canonic materials: the addition of a primary amine runctional polyvinyl alcoho! provides excellent binding strength with the sihea pigments useo in ink jet coatings: the addition of a primar. amine functional poiyvinyl alcohol provides excellent ink optical density with regard to monochrome black, composite black, and primary colors; the addition of a primary amine functional poiyvinyl alcohol provides excellent waterfastness to the printed inks: the aoditiori of a pnmary amine rmctionol poiyviny1 alcohol provides for excellent lightlaslncss of the inks: the addition of a pnmary amine functional polyvinyl alcohol prnvides for excelleni rheologlcal response in terms of shear thickening response when used in conjunction with silica pigment thereby helping the paper coater achieve a greater coating solids level which can allow for higher coat weights and increased production speeds: and the addition of a pnman amine functional polyvinl alcohol provides excellent ink dry time after printing onto the coated ink jet paper. Typically, a primary amine functional polyvinyl alcohol is selected from the group consisting of hydrolyzed copolymers of vinyl acetate and N-vinylamide a hydrolyzed copolymer of vinyl acetate and allylamine. and primary aminoalkylal derivatives of polyxvinyl alcohol. Brief Description of Drawings The invention is described in detail below in connection with the various figures, in which: Figure 1 is a bar graph showing monochrome black ink iet optical density as a function of the resin employed and amount of mineral filler: Figure 2 is a bar graph showing composite biack optical density as a function of the resin employed and amount of mineral filler: Figure 3 is a bar graph showing magenta optical density as a function of filler level and resin employed: Figure 4 is a bar graph snowing yellow optical density as a function of the resin employed and silica content: Figure 5 is a bar graph snowing cyan optical density as a function of the resin employed and the silica tiller level: Figure 6 is a plot of viscosin vs. shea- rate for various ink jet coating formulations: Figure 7 is a bar graph illustrating ink dry time on various silica poly(vinyl alcohol) coatings: Figure S is a bar graph showing monochrome and composite black optical densities for various coated and uncoated base sheets: Figure 9 is a bar graph illustrating waterfastness of monochrome black ink with papers surface sized and coated with various resins; Figure Id is a bar graph showing dry tensile strength of surface sized versus coated papers: Figure 11 is a bar graph of monochrome and composite black optical density for various coated papers: Figure 12 is a bar graph showing waterfastness of monochrome black ink for coated and uncoated base sheets: and Figure 13 is a bar graph showing monochrome black and composite black optical density for various coated and uncoated papers. Detailed Description of the Invention The invention relates to improvements in paper products preferentially suited for use with ink jet printers. The key to the preparation of improved paper products for ink jet printing is in the ink jet coating applied to the surface of the paper. In particular, the improvement resides in the incorporation of an amine functional polyvinyl alcohol polymer as a binder for the ink jet coating. Amine functional polyvinyl alcohols are knowr. and representative examples of such amine functional polyvinyl alcohols are set forth in Rabeson et al. US Patent 5380.403 and are incorporated by reference. For purposes of completeness and expanding upon the general teachings of Robeson el al. methods for preparing amine functional polyl vinyl alcohols) include copoiymerization of vinyl acetate with an N-vinyiamide. e.g.. N-vinylformamide or N-vinyi aceiamide. or copoiymerization with allyl amine followed by hydrolysis, or by polymerization of vinvl acetate followed by hydrolysis to form the poiyvinyl alcohol derivative and then by reaction with 4-amino butyraldehyde dimethyl acetal. Other routes may be used to generate the same or similar types of amine functional polyvinyl alcohols. The syntnesis of the precursor vinyl acetate copoiymer can be conducted in solution. slurry suspension or emulsion type polymerizations. Roarignez. in "Principles of Polymer Svstems. P 98-101. 403. 405 ( McGraw-Hill. NY. 1970) describes bulk and solution poivmerization and the specifics of emulsion polymerization. When preparing poly (vinyl acetate ) by suspension polymerization for example, the monomer is typically" dispersed in wa:er contalning a suspending agent such as polyvinl alcohol and then an initiator such as perovde is added. The unreaeied monomer is removed and the polymer Tillered and dried. A preferred route involves polymerization of vinyl acetate and N-vinyl formamide in methanol which results in a "paste" like product which is amenable to hydrolysis. A variety of comonomers. e.g.. ethylenically unsaturated monomers. may be copolymerized with vinyl acetate and or vinyl acetate and N-vinyl formamide or allyl amine to produce amine functional polyvinyl alcohols eopolymers. Representative, but not totally inclusive. ethylenicaly unsaturated monomers include C,-C, esters 0f acrylic acid and methacrylic acid, unsaturated carboxvlic acids, and hydrocarbon monomers. Examples of esters include metbyl methacrylate. ethyl acrylate. butyl acrylate. and 2-ethy lhexyl acrylate. Others include hydroxy esters such as bydroxyethyl acrylate. The monomers typically are used at levels of about 10 mole percent and preferably less than about 5% by weight. A preferred copolymer for use as a binder in ink jet coating formulations consists essentially of vinyl acetate and N-vinyl formamide eopolymers containing from about 70 to 99 mole percent vinyl acetate and from about 1 to 30 mole percent N-vinyl formamide. Reaction temperatures for forming eopolymers of vim 1 acetate and N-vinyl formamide and ally] amine are conventional. The reaction temperature can be controlled by the rate of catalyst addition and by the rate of the heat dissipation therefrom. Generally, it is advantageous to maintain a temperature from about 500 to 7O0C and to a\oid temperatures in excess of about S00C. While temperatures as low as 00 can be used, economically. the lower temperature limit is about 400C. The reaction time will also vary depending upon other variables such as the temperature, the catalyst, and the desired extent of the polymerization. It is generally desirable to continue the reaction until less than about 0.5% of the N-vinylformamide. aliyl amine or vinvl acetate, if emploved. remains unreacted. Under these circumstances, a reaction time of about 6 hours has been found to be generally sufficient for complete polymerization, but reaction times ranging from about 3 to 10 hours have been used, and other reaction times can be employed, if desired. The hydrolysis of the vinyl acetate copolymers of this invention can be accomplished using methods typically utilized for poly (vinyl alcohol). Either acid or base hvdroivsis or combinations thereof can be conducted to yield the amine functional poiy( vinyl alcohols) of this invention. The hydrolysis often is conducted in several steps: the first step involving contacting with a catalvtic amount of base (e.g. K.OH. NaOH) which results in the hydrolysis of vinyl acetate groups. Hydrolysis o! the vinyl amide groups can be accomplishment by higher levels of base or hy acid addition followed by proper time""temperature to yield the desired level of hydrolysis. In the case of acid hydrolysis, the amine group is prolonated to yield a positive charge neutralized wiih an anionic group (e.g. CT. Br". HSO1. H2PO2. and the like). Both the amine (-NH2 or protorated versions (NH2 X) are suitable in this invention. Acids suitable for effecting hydrolysis include mineral acids such as hydrochloric, sulfuric. nitric, phosphoric and other mineral acids commonly used, as well as organic acids such as para-toluene sulfonic acid, methnnesulfonic acid, oxalic acid and the like. Acidic salts comprised of weak bases and stronu acids, e.g.. ammonium bisulfate. alkyl ammonium bisuifates such as tetrabutylammonium bisulfate can be used. For further detail. the hydrolysis of poly (vinyl alcohol) and copolymers is described in the book "Poly(vinyl alcohol): Properties and Applications", ed. by C.A. Finch. John Wiley & Sons. New York. 1973. p. 91-120. and "Poly(vinyl alcohol) Fibers" ed. by l. Sokuruda. Marcel Dekker. Inc.. New York. 1985. p. 57-68. A recent review- of poly(vinyl alcohol) was given by F. L. Marten in the Encyclopedia of Polymer Science and Engineering. 2nd ed.. Vol. 1 7. p. 167. John Wiley & Sons. New York. 1989. Both references are incorporated by reference. Another potential route for achieving amine functional poly(vinyl alcohols) for use in preparing the ink jet coatings, as noted supra, involves the reaction of specific blocked alkyl amine aldehydes with polyvinyl aicohol or polyvinyl alcohol copolymers to produce ammo functional poiwinvl alcohols. Blocked alky 1 aldehydes include 4-amino butyral dimethyl acetal and ether aikyl acetals which react with polyvinyl to produce the 4-amino alkylal of polyvinyl alcohol, e.g.. the 4-aminobutryral of polyvinyl alcohol. The incorporation of primary amine functionality in the amine functional polyvinyl alcohol, e.g.. hvdrolvzed vinyl acetate N-vinylfom amide or hydrolyzed vinyl acetate allyl amine copolvmers or polyvml alcohol aminobutyral polymers is within the range of from about 1 to amounts of up to about 30. preferablv about 5 to 20 mole%. The desired level of vinyl acetate conversion to vinyl alcohol is from about 75 to 100%. preferably from about SO to 99% hvdrolvsis ana the level of vinylarnide conversion to vinylamine is from about 25 to fully hvdrolvzed. e.g.. about 100%.. In some preferred embodiments the hydroiyzed vinyl acetate is present in an amount of from about SO to 95 moie percent. The following sets forth operati\e and preferred ranges regarding the use of an amine functional polyvinvl alcohol. It is understood that the values identnied are "about" or approximate ranges. Operative and Preferred Ranges of the Composition: Primary Amine functional PVOH Molecular weight (wt. average) Primary Amine Content Acetate Hydrolysis wt. % binder in ink jet coating Coaling pH Ink Jet coating formulations typically incorporate silica pigment and possibly a small amount of another mineral pigment in the formulation. Typically, the mineral pigment is silica and is incorporated in the ink jet coating formulation in amounts which range from about I to 90%. preferably about 30 to 85%. by weight. The level of binder (solids basis) will range within conventional levels or about 20 to 80% by weight of the ink jet formulation. The levels of pigment and binder depend significantly upon the type of coater used in the preparation of the ink jet paper. Synthetic aluminum silicates having surface areas of about 100 nr per gram as well as clay. talc, calcium carbonate, magnesium silicate and the like have been used as fillers m ink jet coating compositions and can be used. the preferred filler for ink jet coating compositions is silica having a surface area of about 50 to 700 nr gram. Ink iet formulations may also contain conventional additives such as defoamers. surface acme agents, dyes, ultraviolet absorbents, pigment dispersants. moid inhibitors, thickeners and water-resisting agents. The ink jet formulation usually is applied to the paper surface in amounts ranging from about 2 to 20 grams per nr . Coat weight is somewhat dependent upon the type of coating applicator. The ink iet coating incorporating the amine functional poiyvinyl alcohol is supplied to the paper surface itself rather than to paper stock prior to sheet formation. Not intending to be bound by theory, it is believed the amine group in the amine functional polymers provides a cationic charge on the paper surface which reacts with the anlonio sulfonie acid groups of the direct or acid dye of the ink jet inks to form an insoiuble sail. By forming an insoluble salt, the inks become waterast on the paper surface and the ligitfastness is improved in those paper products incorporating the amine functional polyvinyl alcohol as compared to ink iet coatings incorporating poly(vinyl alcohol) nomopol"ymer as the binder. Pigment binding strength, and silica pigmem binding strength in particular, is improved with the use of the ink jet coatings incorporating the amine functional poiy(vinyl alcohol) polymers in comparison to the ink jet coalings incorporating the po!y(vinyl alcohol) homopolymer due to the strong absorption of the amines with the silanol group on the silica pigment. The following examples are provided to illustrate the preparation of suitable aminc functional polyvinyl alcohols and to illustrate ink jet coating systems for paper. Example 1 Procedure for Forming Primary Amine Functional Polvvinvl Alcohols A poly(vinyl alcohol/vinyl amine) copclyrner herein referred to as PYOH/PVNH2 (6 mole% vinyl aminel was prepared by first polymerizing a vinyl acetate/N-vinylformamide (94/6 molar copolymer in methanol by free radical polymerization procedures. The vinyl acetate, N- vinyl formamide copolymer was hydrolyzed to a vinyl alcohol/N-vinylfonnamide copolymer by alkali saponification of vinyl acetate using 0. i molar sodium methoxide in methanol. The vinyl alcohol N-vilnylformannae copohmer was by droiyzed to a vinyl aicohoi vinyl amine-HCl copolymer by heating at 90 C for 6 hours in distilled water to which concentrated HCl was added. The product was precipitated using methanol and then dried in a vacuum oven. The average molecular weight of the PYOH PVNH2- copolymer was about 95.000 ( Mwt. the percent bydrolysis ot the acetate was 100% and the percent hydrolysis of the X-vinylformamide was 100%. A second poly (vinyl alcohol vinyl amine) copolymer (PYOH PVNH2) ( 12 mole% vinvl amine) was prepared by first polymerizing a vitny1 acetate N-vinylformamide (88 12 molar) copolymer in. methanol by free radical polymerization procedures. The molecular weight of the PV"OH PVNH, copolymer was 96.000. the percent hydrohsis of the acetate was 100% and the percent bydrolysis of the N-vinylformamide was 100%. Example 2 Procedure for Producing Priman Amine Functional Poly vinyl Alcohol 1.sing --Ammo But- aldeinde Dimethylacetal 12 mole % anmine) Poly vinyl) 1 aicohol ( Airvol 100 was dissoilved in water (270 ml) at 700C under N2. Alter dissolution, concentrated hydrochloric acid (1 6.34g. 0.1 70 mole) and 4- aminobuiyruldehyde dimethyl acctal (ABAA) (18.14g. 0.136 mole) were added to the reaction along with additional water (20 ml). The reaction was continued at 750C for 6 hours and cooled to room temperature. The polymer product was isolated by precipitation in acetone, washed with further acetone and dried in a vacuum oven (600C/l torr)". The composition of the resultant polymer as determined by 13"C NMR. was 12% mole % 4-aminobutyral incorporation. Example 3 Coating Adhesive Strength Several silica pigmented coatings were prepared in conventional manner for the purpose of evaluating coating adhesive strength, one type incorporating a polyvinyl alcohol homopolymer and the other type incorporating a PVOH/PVNH2 copolymer as the binder. The coatings were formulated with 100 parts precipitated silica pigment and 40 pans of Airvol 125 polyvinyl alcohol (A 125) in the one case and an ainine functional polyvinyl alcohol of the type in Example 1 having 12 mole% amine MMW PVOH/PVNH2 in the other case and then applied to the paper at a coating weight of approximately 6 grams m2 . In preparing the coatings the polyvinyl alcohol was solubilized in water to a concentration of about 10% solids by weight. The pigment was ther. added. The testing was performed on an IGT model AIC2-5 following T.APPI procedure T514. The larger the value, the greater the coating strength. Table 1 sets forth conditions and results. Table 1 1GT Pick Strength of Coating Containing PVOH Homopolymer and PVOHPVNH2 Copolymer Sample Identification IGT Pick Strength 40 pans A125 (99.3% hydrolysis MMW PVOH1 ) 6..5 40 pans 12 mole % MMW PVOH PVNH2 7.83 "MMW PVOH refers to medium molecular weight or weight average molecular weight of approximateb, 110.000 2MMW PVOH NH2 refers to medium moiecular weignr or weigni average molecular weight of approximately 06.000. The results show the vin\! alcohol vinyl amine copolymer containing 12 molar% hydrolyzcd N-vinylformamide gave higher pick strengths than the PVOH homopoly mer. thus showing the enhanced binding properties of the ink jet coating due to the presence of the pamary amine. Example 4 Printed Ink Optical Density Sheets of uncoated base sheet were coated for the purpose of evaluating ink jet optical density. Several colors were evaluated. One set of base sheets was coated with an ink jet coating comprising PYOH and silica pigment and another set was coated with an ink jet coaling comprising 6 mole% MMW PVOH/PVNH2 and silica pigment coating using a Meyer Rod drawn down bar. The level of binder was varied from 70 weight parts to 30 weight pans per 100 weight parts silica. Coat weight was in the range of 4 to 6 grams"m2. After coating and drying, the sheets were printed with an Hewlett Packard 560 ink jet printer using an HP test pattern distributed by Hewlett Packard for the purpose of testing ink jet paper media. After printing the samples were measured for optical density using a Tobias IQ 200 Reflection Densitometer. Figures 1 through 5 compare the ink optical density of the ink jet coatings comprising PYOH PY\H: copolymer binder versus the ink jet coatings comprising the standard PYOH binder. In the Figures: * 100% PYOH means that no silica was incorporated into the ink jet coating formulation. Airvol 125 polyvinyl alcohol is 99.3% hydrolyzed and has a molecular weight (Mw) of 100.000. Airvo! 325 polyvinyl alcohol is 98.0% hydrolyzed and has a molecular weight (Mw) of 110.000. Airvol 523 poiyvinyl alcohol is 88.0% hvdrolyzed and has a molecular weight (Mw) of 110.000. PYOH PVAm is another abbreviation for PYOH PVNH2 the amine functional poiyvmyl alcohol of Example 1. Figure 1 shows thai monochrome ink jet optical density for the paper naving the ink jet coating incorporating the PVOH PV NH2 binder was superior to the paper having the ink jet coating incorporating the poiyvinyl alcohol in all cases except at the highest loading. On the other hand, the PYOH "PVNH2 based coating remained essentially constant at al levels Figure 2 shows that a: low levels of binder to silica, the PYOH Vam was superior to the PYOH thus showing enhanced binding strength. Figure 3 compares the magenta optical density achieved with the various coatings and particularly that the PVOH VA\m eopolymer was superior in about every category to the PVOH and especially at the low binder t to pigment levels. It may be seen in Figure 4 that the poivinyl alcohol polyviny lamine binder was significant!} better in performance vis-a-vis PYOH in the yellow optical density test. In contrast to the previons optical density test, substantially superior results were obtained with the amine functional polyvinyl alcohol at all levels. It is seen in Figure 5 that comparable results were obtained with the PYOH"YAm binder at high loadings but greater properties at the lower loading. Example 5 Waterfastness The waterfastness of inks printed onto a paper coated with an ink jet coating incorporating PVOH/PVNH2 as the binder was compared to paper coated with the ink jet coating incorporating the PVOH homonolymer. The test was performed by first measuring the monochrome black ink density after printing. The printed area was then immersed in distilled water for 30 seconds ana dried on a hot plate under tension. The optical density was then measured again The results are set forth in Table -2. Table 2 Watcrfasmess on Ink Jet Paper Coated With PVOH and PVOH"PVNH2, Binders ? Represents the Difference in Optical Density Between Pre Wet and Post Wet Paper Products Table 2 shows that the waterfasmess of printed inks is improved when the printing is effected omo a paper product having a silica based ink jet coating which incorporates the amine functional polyvinyi alcohol. As a binder, these results show that the loss in optical density after wetting decreases as the level of 6 mole%( PVOH"PVNH2 was increased in the coaling. These results also show that the ink jet coating incorporating the 12 moie% PVOH PVNH2- provides improved waterfastness as compared to the 6 rnoie°o PVOH"PVNH2;. copoiymer a: approximately equal addition levels. Example 6 Rheology of ink let coatings Several ink jet coating formulations were prepared using different binders to determine their effect on the rheology of the resulting ink jet formulations. The graph (Fiiune 6) demonstrates the shear vs. visoosity response for a 13% solids coating formulated with 100 parts silica and 40 parts binder. Four hinder types were used and they are: 1. Fully hydrolyzed medium molecular weight PVOH (FH MMW) the molecular weight was approximately 110.000. 2. Pan-ally hydrolyzed medium molecular weight PVOH (PHNH2 MMW) the molecular weight was approximate!) 110.000. 3. PVOH/ PVNH2 medium molecular weight 6 mole%. HC1 salt): the molecular weight was approximately 95.000. 4. PYOH"PVNH2 medium molecular weight 12 mole % free base: the molecular weight was approximately 96.000. The shear viscosity of the coatings was measured with an ACAV High Shear Capillary Visoometer at temperatures of 35 100C The results in Figure 6 show that the silica based Ink Jet coatings incorporating the polyvinyl alcohol) vinyl amine ecpolymer binders produce a much lower viscosin response as compared to ink jet coatings incorporating poly vinyl alcohol) homopolymer as the binder. The mechanism for the reduced viscosity response to high shear is not known but may relate to the hish absorption of the amine functional PVOH onto the surface of the silica pigment. It is believed a greater absorption of the copolymer onto the surface of the silica would prevent the Polymer chains from extending into the liquid phase of the coating thereby lowering the overall iscosity of the coating. The data also supports the view that the greater the amine content in the binder, the greater the absorption and the lower the snear thickening response. Example 7 Lighfastness Several ink jet formulations were prepared for the purpose of determining the itghtfastness of the formulations The following table demonstrates the UV hghtfasiness of ink jet primed sheets with coatings based on 100 parts precipitated siiice pigment. Lignvfasiness was determined by measuring the optical density of ink jet printed papers before and after exposure 54 hour UV light exposure. The optical densities of the paper were measured with a Tobias IQ 200 Reflection Denshometer. The printed sheet then was exposed to UV light usinu a Q-U-V Accelerated Weathering Tester. The \alues were recorded and set forth in Table 5. ? represents the difference in optical density between the initial and exposed samples, the lower the value, the better the lightfastness. The results show that the lightfastness of ink jet primed colors improved when the PYOH PVNH2- copolymer was used as a binder for the ink jet coating compared to when PVOH hornopohmer was used as the binder for ink jet coatings. Lightfastness also improved with increased PVOH PVNH2 binder level in the coating as well as with increased amine content in the copolymer backbone. The mechanism for improved lightestness is not understood but may be due an increased light stability of the salt complex formed between the sulfonic acid groups of the dyes used in the inks and the amine in the amine functional polyvinyl alcohol. Example 8 Dry Time Ink Jet coating formulations were prepared which vary in the % hydrolysis ol the various PVOH binders and compared for ink dry time (the time it lakes the ink to dry after printing from an ink jet primer) to a similar formulation which contained a 12 mole% medium molecular weight PVOH"PYAm binder. The coating consisted of a 100 parts precipitated silica pigment with 40 parts of the PVOH or PVOHPVAm binder prepared at a total solids level of 15% The formulations were Meyer Rod coated on to an base paper at coat weights between 7 and S grams square meter. The coated papers were tested for ink dry time according to procedures outlined in the "Hewlett Packard Paper Acceptance Criteria For HP Deskjet 500C. 550C & 560C Printers". Results are shown in Figure 7. wherein: PH MMW refers to 87% hydrolysis at approximately 110.000 average molecular weight-.: 1H MMW refers to 96% hydrolysis at approximately 110.000 average molecular weight SH MMW refers to 87% hydrolysis at approximately 110.000 average molecular weight: and PVOH"PVAm refers to 12 mole% vinyl amine at 95.000 average molecular weight. Figure7 demonstrates the improved dry time of the ink jet formulations containing PYOH PVAm versus the formulations containing the PVOH homopolymer. Example 9 Ink Jet Impregnated Paper Product Paper products were prepared in accordance with the general procedure of US Patent 4.880.497 in that the paper product was impregnated with the binder prior to coating rather than being applied the surface of the paper as a coating. The obiective was to determine whether comparable ink jet; properties could be achieved by impregnation, vis-a-vis coating, in addition to improving the paper"s wet and dry strength. As a second objective. me amine functional poiyvmyl alcohol, viz., hydrolyzed vinyl acetate n-vinyiformaniide was replaced and a commercial quaternized poiyvinyl alcohol substituted therefor. Paper products were prepared by adding the aqueous binder to a paper substrate a! the size press as opposed to applying the binder 10 the surface of" the paper as a paper coaling. Three methods were employed as follows: 1. Three base sheets were prepared, one haying no coating. another coated with polyvinyl alcohol and another coated with amine functional polyvinyl alcohol. Silica was bound to the paper via the binder": no silica was employed in the absence of the binder. 2. Three base sheets were prepared in accordance with 1 above except the paper was surface sized (impregnated ) with polyvinyl alcohol prior to coating w ith pol\ vinyl alcohol or amine functional polyvinyl alcohol. 3. Three base sheets were prepared n accordance with 2 above except the paper was surface sized with the amine functional polyvinyl alcohol prior to coating with the respective binders. The results are set forth in Figures 8. 9 and 10. Results Summary Surface sizing a paper substrate with 12 mole % medium molecular weight PYOH YAm provided improved levels of optical density (one measure of ink jet printability) in comparison to sheets surfaced sized with Airvol 523 homopolymer and the non surface sized base sheet (Figure 8). However, the results show that by applying the binder as a coating as opposed to impregnation, the ink jet printing quality is enhanced substantial!}-. There appears to be little difference between the optical density in o PVOH PVNH2 coated paper and a PVOH "PV NH2 impregnated and coated paper. Ink waterfastness of the three papers was very similar (see Figure 9). Airvol 523 polyvinyl aicohol surface sized sheets provided a higher level of paper drv strength in comparison to the PVOH VAm. Both surface size sheets provided strength greater than the base sheet. Example 10 This example provides a comparison between ink jet papers coated with a PVOH "PVNH2 aqueous binder and one coated with a eationic polyvinyl aicohoi sold by K.uraray as canonic polymer. C506. The results are shown in Figures 11 and 12. Fieure 11 show-s that coating the base sheet with a coating containing 100 cans of silica pigment and 40 parts of PVOH VAm; provided le. eis of ink optical density which were much greater than coatings containing 1 00 pans of sihea pigment with either 40 pans of Airvol 523 or 40 parts of thc Kuriaray cationic polymer. C506. -Ml coaled papers provided levels of optical density which were greater than sheets which were surface sized only. Figure 12 shows that ink waterfastness was excellent with the PVOH/V"Am coating and very poor with the Airvol 523 poiyvinyl alcohol and the Kuraray cationic polyvinyl alcohol. Dry strength of all coated sheets were approximately equal to each other and slightly greater than the base sheet. The coated sheets were much lower in dry strength as compared to the surface sized sheets. Example 1 1 Ink Jet Paper Using 4-amino butyral derivative of Polyyinyl Alcohol The procedure of Example 2 to make a 4-aminobutyral derivative of poly vinyl alcohol was followed except the polymer contained 7 mole% amine functionality. It was compared to polvvinvl alcohol as a binder and to other amine functional alcohols derived by the hydrolysis of a vinyl acetate-N-vinyl formamide copoiymer having the mole% amine functionality set forth. Figure 13 sets forth the results. The results show each of the amine functional polyvinyl alcohols were superior to polyviny1 alcohol. The table also shows that the 7% amine functionality was equivalent to the 12 and 18% mole functional bydrolyzed vinyl acetate N-vinyl formamide polymer systems. In summary, the amine functional polyvinyl alcohols provide excellent properties to ink jet coatings for paper products and particularl; those ink iet coatings based upon silica. In almost every case the properties were improved vis-a-vis polyvinyl alcohol. When comparing the polyviny] alcohol polyvmyl amine binders, the 12 moie% amine was superior to 6 moie% amine. This is believed evidence that the amine provides cationic sites on the poiymer backbone which react with the inks from the ink jet printer to improve the ink optical density ink waterfastness. and ink light stabilitv. The greater the amine content, the greater rhe improvements. The amine group also contributes to the binding power of the binder and silica. It is also observed that the 4-aminobutyral derivative of polyvinyi alcohol affords slightly superior results to the hydrolyzed vinyl acetate N-vinylformamide polymers. This is believed due to the fact that the primary amine groups are in the form of extended side chains pendent from the poiymer backbone wherein the hydroivzed N-vinyl formamide groups are closely bound to the poivmer backbone. It is believed the side chains allow the amine cationic site better access to the inks and also allows the amine to more easily combine with the sihea. WE CLAIM: An ink jet printing paper product having applied to its surface an ink jet coating formulation comprising a mineral pigment and an aqueous based polymeric binder applied to its surface, the improvement which comprises incorporating a primary amine functional polyvinyl alcohol as the polymeric binder, said primary amine functional polyvinyl alcohol being selected from the group consisting of a hydrolyzed copolymer of vinyl acetate and N-vinyl amide, a hydrolyzed copolymer of vinyl acetate and allyl amine, and an aminoallcylal derivative of polyvinyl alcohol. The paper product as claimed in Claim 1 wherein the mineral pigment is silica. The paper product as claimed in Claim 1 wherein the primary amine functionality in said amine functional polyvinyl alcohol is from 1 to 30 mole percent. The paper product as claimed in Claim 1, wherein the primary atnine functional polyvinyl alcohol is an arainoalkylal derivative of polyvinyl alcohol. The paper product as claimed in Claim 5, wherain the primary amine functional polyvinyl alcohol is the 4- aminobutyral of polyvinyl alcohol. The paper product as claimed in Claim 1, wherein the primary amine functional polyvinyl alcohol is a hydrolyzed copolymer of vinyl acetate and allyl amine. The paper product as claimed in Claim 1, wherein the primary amine functional polyvinyl alcohol is a hydrolyzed copolymer of vinyl acetate N-vinylamide. The paper product as claimed in Claim 7 wherein said N-vinylamide is N-vinylformamide. The paper product as claimed in claim 8, wherein said N-vinylamide is N-vinylacetamide. The paper product as claimed in Claim 1 wherein the silica is present in an amount of from 30 to 85% by weight of the ink jet coating formulation. The paper product as claimed in Claim 10 wherein the ink jet coating formulation is applied to the surface in an amount of from 2 to 20 grams per m2. The paper product as claimed in Claim 11 wherein the binder is incorporated into the ink jet coating formulation in an amount of from 20 to 60% by weight. The paper product as claimed in claim 11 wherein the copolymer polyvinyl alcohol and polyvinyl amine polymer is a hydrolyzed copolymer of vinyl acetate and N-vinylamide. The paper product as claimed in Claim 12 wherein the hydrolyzed copolymer consists essentially of hydrolyzed vinyl acetate and N-vinyl formamide • and the hydrolyzed vinyl acetate is present in an amount from 80 to 95 mole percent. The paper product as claimed in Claim 11 wherein the amine functional polyvinyl alcohol is the 4- aminobutyral of polyvinyl alcohol. The paper product as claimed in Claim 11 wherein the amine functional polyvinyl alcohol is a hydrolyzed copolymer of vinyl acetate and allyl amine. In a process for preparing an ink jet recording sheet which comprises applying an ink jet coating to a paper substrate, said ink jet coating comprising a polymeric binder and a mineral pigment, the improvement which comprises utilizing a primary amine functional polyvinyl alcohol as the polymeric binder, said primary amine functional polyvinyl alcohol being selected from the group consisting of a hydrolyzed copolymer of vinyl acetate and N-vinyl amide, a hydrolyzed copolymer of vinyl acetate and allyl amine, and an aminoalkylal derivative of polyvinyl alcohol. The process as claimed in Claim 17 wherein the mineral pigment is silica. The process as claimed in claim 18 wherein the primary amine functionality in said amine functional polyvinyl alcohol is from 1 to 30 mole percent. The process as claimed in Claim 18 wherein the silica is present in an amount of from 30 to 85% by weight of the ink jet coating formulation. The process as claimed in Claim 20 wherein the ink jet coating formulation is applied to the surface in an amount of from 2 to 20 grams per m2. The process as claimed in claim 21 wherein the binder is incorporated into the ink jet coating formulation in an amount of from 20 to 60% by weight. The process as claimed in claim 22 wherein the copolymer polyvinyl alcohol and polyvinyl amine polymer is a hydrolyzed copolymer of vinyl acetate and N-vinylamide. The process as claimed in claim 23 wherein the hydrolyzed copolymer consists essentially of hydrolyzed vinyl acetate and N-vinyl formamide and the hydrolyzed vinyl acetate is present in amount from 80 to 95 mole percent. This imention relates to an improvement in coalings particularly suited lor the preparation of paper productshaving an ink jet coating applied thereto and to the resulting paper products. The improvement in ink jet coalings resides in the incorporation of a primary amme functional polyvinyl alcohol (PVOH/PVNH2) as a polymeric binder. One form of an amine functional polyvinyl alcohol is produced by the hydrolysis of a copolymer of vinyl acetate and N- vinylformamide or vinyl acetate and allyl amine. Another is the polyvinyl butyral derivative of polyvinvl alcohol which typically is formed by the reaction of a 4-amino alkyl aldehyde dialkyl acetal. such as 4-aminobutyraldehyde dimethyl acetal with polyvinyl alcohol.

Full Text

INK JET PRINTING PAPER INCORPORATING
AMINE FUNCTIONAL POLY(VINYL ALCOHOL)
Technical Field
This invention relates to paper products having a unique coaling thereon rendering them
well suited for use with ink jet printers.
Background of the Invention
Advances in ink jet printing technology. ha\e placed new demands on the printed paper
and paper coatings. To function properly the printed substrate must quickly absorb the ink and
ink vehicles directly after printing, maximize the ink optical density, minimize ink bleed and
wicking. and provide a means of making the inks waterfast.
Ink Jet coatings generally comprise silica pigment having a high absorption capability and
a polymeric binder such as a polyi vinyl alcohol) binder having a high binding strength. A
variety of additives have been utilized to improve coating properties. Cationic additives, for
example, have been added to help with ink waterfastness and lightfastness. Other variations in
the ink jet coating formulations include the use of non silica pigments such as ciays. aluminum
hvdrate. calcium carbonate, titanium dioxide, magnesium carbonate and the use of binders such
as stvrene-butadiene. polyvinyl pyrrolidone. polyvinyl acetate, acrylic binders, and starch.
The following patents and articles are representative of various resins and ink jet paper
coatings.
US 4.818.341 discloses the addition of a cationic polymer e.g. hydroiyzed vinyl acetate
or vinyl propionate N-vinyl formamide copolymers to paper stock to enhance the dry-strength in
all tvpes of paper and paper board, e.g.. writing paper and packaging papers. The polymers are
added in an amount of from 35-1 50 grams per square meter for paper and up to 600 grams per
square meter for paper board.
US 4.880.197 discloses the addition of water-soluble copolymers containing polymerized
vinvl amine units, e.g.. a hydrolyzed vinyl acetate N-vinyl formamide copolymer to paper stock
prior to sheet formation in an amount of from 0.1-50%. based on cry fiber.
Japanese-laid open Kokai application 5-28323 discloses a recording sheet having good
ink absorptivity, image quality and excellent water resistance which comprises a dye fixing layer
and ink adsorption layer laminated thereon. One of the principal components of the dye fixing
layer applied to the recording sheet is a cation modified polyvinyl alcohol. Cation modified
polyvinyl alcohols are characterized as hydrolyzed copolymers of viny1 acetate and ethylenically
unsaiurated monomers having quaternary ammonium salt groups. The content of the cationic
group is from 0.1 -10) mole percent
An abstract, of Japanese 63162276A2 discloses an image acceptor for ink jet recordings.
The image acceptor includes silica pretreated with water soluble resins either on the recording
surface or within the acceptor. A solution of sodium silicate and sulfuric acid is mixed with 5%
of a cation modified polyvim I alcohol and applied to a paper sheet and then an ink applied
t hereto.
Japanese Patent 05139023 discloses an aqueous based ink jet coating comprising silica
pigment and a fully hydrolyzed. medium molecular weight poly (viny1 alcohol) coating. This
coating is applied to a paper support at coat weights of 0.7 to O.8g/cm2 to provide high color
quality images with good dot shape.
German patent 514633 Al 921125 describes an ink jet coating which contains 50% silica
pigment. 40% poly(vinyl alcohol) having a hydrolysis value of 92.5%. and 10% of a cationic
polyacrylamide. When applied to a paper substrate at a coating weight of 10 grams/m2 this
coating provides excellent color density;. and small dot diameter? yielding excellent print fidelity.
Japanese patent 01186372 A2 890725 describes the addition of polyacrylamide to an ink
iet coating comprising silica pigment and fully hydrolyzed low molecular weight poly ( vinyl
alcohel ) This coating yield good smudge resistance and hghttastness.
Japanese patent 06247036 A2 940906 discloses the use of a cationic polyethl leneimine
quatemar} ammonium salt in combination with silica pigment and fully hydrolyzed low
molecuiar weight poly (vinyl alcohol) as an ink jet receiving iayer.
Japanese patent 61134291 A2 S60621 discloses a cationic PYOH binder for use in an ink
let coating the binder used is a saponified tnmethyl-3-( l-acry)amidopropyhammonium". chloride
- v inyl acetate copolymer with a percent hydrolysis of 98.5 and a cationic content of 3 moie %
and :: degree of polymerization of 1 750. Coatings using this binder with silica pigment provide
excellent print fidelity and good water resistance to paper.
US 5.405.678 discloses an ink jet paper having a substrate coated with a non coalesced
latex film comprised of a hydrophobic polymer. e.g.. ethylene-vinyl chloride copolymers. acrylic
latexe. sillca, and disnersants.
US 5.270. 103 discloses receiver sheets suited for printing with aqueous based inks, such
as those used in ink jet printing systems. The coaling formulation is comprised of a pigment a:xl
a binder consisting of polyvinyl alcohol and another polymer. e.g.. eationic polyvinyl alcohol and
poly(vinyl pyrrolidone).
US 6.096.826 discloses the synthesis of a amine functional polyvinyl alcohol via the
reaction piperidone with poiy(v inyl alcohol) particles. The end product was found 10 be useful
as a mordant/binder for ink jet coated papers.
US 6.096.440 discloses the use of an ink jet recording medium having an ink receiving
!ayer composed of hydrophilie resin, a block copolymer of poly viny1 alcohol and a hydrophobie
polymer. US -440 further discusses the use of a cationic-modified poly (vinyl alcohol). Kurray
CM-318. produced by Kuraray Co. Ltd. as a binder for the ink jet receiving lyer.
Summary of the Invention
This invention relates to an improvement in paper products having an aqueous based ink
jet coating applied to its surface. The improvement generally resides in the incorporation of an a
primary amine functional polyvinyl alcohol (PVOH PVNH2) as a polymeric binder in the ink jet
coating. One form of an amine functional polyvinyl alcohol is produced by the hydrolysis of a
copoiymer of vinyl acetate and N-vinylfotmamide (PVOH PVNH2). another formed by the
polymerization of vinyl acetate and ailyl amine. and another is the 4-aminobutyral derivative of
polyvinyl alcohol.
Several advantages are associated with the paper products incorporating the improved ink
jet coating. These advantages include:
the incorporation of a primary amine functional poiyvinyl alcohol as a
polymer binder in the ink jet coating eases the makedown procedure of the coating
formulation by eliminating the need to add canonic materials:
the addition of a primary amine runctional polyvinyl alcoho! provides
excellent binding strength with the sihea pigments useo in ink jet coatings:
the addition of a primar. amine functional poiyvinyl alcohol provides
excellent ink optical density with regard to monochrome black, composite black,
and primary colors;
the addition of a primary amine functional poiyvinyl alcohol provides
excellent waterfastness to the printed inks:
the aoditiori of a pnmary amine rmctionol poiyviny1 alcohol provides for
excellent lightlaslncss of the inks:
the addition of a pnmary amine functional polyvinyl alcohol prnvides for
excelleni rheologlcal response in terms of shear thickening response when used in
conjunction with silica pigment thereby helping the paper coater achieve a greater
coating solids level which can allow for higher coat weights and increased
production speeds: and
the addition of a pnman amine functional polyvinl alcohol provides
excellent ink dry time after printing onto the coated ink jet paper.
Typically, a primary amine functional polyvinyl alcohol is selected from the group
consisting of hydrolyzed copolymers of vinyl acetate and N-vinylamide a hydrolyzed
copolymer of vinyl acetate and allylamine. and primary aminoalkylal derivatives of polyxvinyl
alcohol.
Brief Description of Drawings
The invention is described in detail below in connection with the various figures, in
which:
Figure 1 is a bar graph showing monochrome black ink iet optical density as a function
of the resin employed and amount of mineral filler:
Figure 2 is a bar graph showing composite biack optical density as a function of the resin
employed and amount of mineral filler:
Figure 3 is a bar graph showing magenta optical density as a function of filler level and
resin employed:
Figure 4 is a bar graph snowing yellow optical density as a function of the resin
employed and silica content:
Figure 5 is a bar graph snowing cyan optical density as a function of the resin employed
and the silica tiller level:
Figure 6 is a plot of viscosin vs. shea- rate for various ink jet coating formulations:
Figure 7 is a bar graph illustrating ink dry time on various silica poly(vinyl alcohol)
coatings:
Figure S is a bar graph showing monochrome and composite black optical densities for
various coated and uncoated base sheets:
Figure 9 is a bar graph illustrating waterfastness of monochrome black ink with papers
surface sized and coated with various resins;
Figure Id is a bar graph showing dry tensile strength of surface sized versus coated
papers:
Figure 11 is a bar graph of monochrome and composite black optical density for various
coated papers:
Figure 12 is a bar graph showing waterfastness of monochrome black ink for coated and
uncoated base sheets: and
Figure 13 is a bar graph showing monochrome black and composite black optical density
for various coated and uncoated papers.
Detailed Description of the Invention
The invention relates to improvements in paper products preferentially suited for use
with ink jet printers. The key to the preparation of improved paper products for ink jet printing
is in the ink jet coating applied to the surface of the paper. In particular, the improvement
resides in the incorporation of an amine functional polyvinyl alcohol polymer as a binder for the
ink jet coating.
Amine functional polyvinyl alcohols are knowr. and representative examples of such
amine functional polyvinyl alcohols are set forth in Rabeson et al. US Patent 5380.403 and are
incorporated by reference. For purposes of completeness and expanding upon the general
teachings of Robeson el al. methods for preparing amine functional polyl vinyl alcohols) include
copoiymerization of vinyl acetate with an N-vinyiamide. e.g.. N-vinylformamide or N-vinyi
aceiamide. or copoiymerization with allyl amine followed by hydrolysis, or by polymerization of
vinvl acetate followed by hydrolysis to form the poiyvinyl alcohol derivative and then by
reaction with 4-amino butyraldehyde dimethyl acetal. Other routes may be used to generate the
same or similar types of amine functional polyvinyl alcohols.
The syntnesis of the precursor vinyl acetate copoiymer can be conducted in solution.
slurry suspension or emulsion type polymerizations. Roarignez. in "Principles of Polymer
Svstems. P 98-101. 403. 405 ( McGraw-Hill. NY. 1970) describes bulk and solution
poivmerization and the specifics of emulsion polymerization. When preparing poly (vinyl
acetate ) by suspension polymerization for example, the monomer is typically" dispersed in wa:er
contalning a suspending agent such as polyvinl alcohol and then an initiator such as perovde
is added. The unreaeied monomer is removed and the polymer Tillered and dried. A preferred
route involves polymerization of vinyl acetate and N-vinyl formamide in methanol which results
in a "paste" like product which is amenable to hydrolysis.
A variety of comonomers. e.g.. ethylenically unsaturated monomers. may be
copolymerized with vinyl acetate and or vinyl acetate and N-vinyl formamide or allyl
amine to produce amine functional polyvinyl alcohols eopolymers. Representative, but not
totally inclusive. ethylenicaly unsaturated monomers include C,-C, esters 0f acrylic acid and
methacrylic acid, unsaturated carboxvlic acids, and hydrocarbon monomers. Examples of esters
include metbyl methacrylate. ethyl acrylate. butyl acrylate. and 2-ethy lhexyl acrylate. Others
include hydroxy esters such as bydroxyethyl acrylate. The monomers typically are used at levels
of about 10 mole percent and preferably less than about 5% by weight.
A preferred copolymer for use as a binder in ink jet coating formulations consists
essentially of vinyl acetate and N-vinyl formamide eopolymers containing from about 70 to 99
mole percent vinyl acetate and from about 1 to 30 mole percent N-vinyl formamide.
Reaction temperatures for forming eopolymers of vim 1 acetate and N-vinyl formamide
and ally] amine are conventional. The reaction temperature can be controlled by the rate of
catalyst addition and by the rate of the heat dissipation therefrom. Generally, it is advantageous
to maintain a temperature from about 500 to 7O0C and to a\oid temperatures in excess of about
S00C. While temperatures as low as 00 can be used, economically. the lower temperature limit
is about 400C.
The reaction time will also vary depending upon other variables such as the temperature,
the catalyst, and the desired extent of the polymerization. It is generally desirable to continue the
reaction until less than about 0.5% of the N-vinylformamide. aliyl amine or vinvl acetate, if
emploved. remains unreacted. Under these circumstances, a reaction time of about 6 hours has
been found to be generally sufficient for complete polymerization, but reaction times ranging
from about 3 to 10 hours have been used, and other reaction times can be employed, if desired.
The hydrolysis of the vinyl acetate copolymers of this invention can be accomplished
using methods typically utilized for poly (vinyl alcohol). Either acid or base hvdroivsis or
combinations thereof can be conducted to yield the amine functional poiy( vinyl alcohols) of this
invention. The hydrolysis often is conducted in several steps: the first step involving contacting
with a catalvtic amount of base (e.g. K.OH. NaOH) which results in the hydrolysis of vinyl
acetate groups. Hydrolysis o! the vinyl amide groups can be accomplishment by higher levels of
base or hy acid addition followed by proper time""temperature to yield the desired level of
hydrolysis. In the case of acid hydrolysis, the amine group is prolonated to yield a positive
charge neutralized wiih an anionic group (e.g. CT. Br". HSO1. H2PO2. and the like). Both the
amine (-NH2 or protorated versions (NH2 X) are suitable in this invention. Acids suitable for
effecting hydrolysis include mineral acids such as hydrochloric, sulfuric. nitric, phosphoric and
other mineral acids commonly used, as well as organic acids such as para-toluene sulfonic acid,
methnnesulfonic acid, oxalic acid and the like. Acidic salts comprised of weak bases and stronu
acids, e.g.. ammonium bisulfate. alkyl ammonium bisuifates such as tetrabutylammonium
bisulfate can be used. For further detail. the hydrolysis of poly (vinyl alcohol) and copolymers is
described in the book "Poly(vinyl alcohol): Properties and Applications", ed. by C.A. Finch.
John Wiley & Sons. New York. 1973. p. 91-120. and "Poly(vinyl alcohol) Fibers" ed. by l.
Sokuruda. Marcel Dekker. Inc.. New York. 1985. p. 57-68. A recent review- of poly(vinyl
alcohol) was given by F. L. Marten in the Encyclopedia of Polymer Science and Engineering.
2nd ed.. Vol. 1 7. p. 167. John Wiley & Sons. New York. 1989. Both references are incorporated
by reference.
Another potential route for achieving amine functional poly(vinyl alcohols) for use in
preparing the ink jet coatings, as noted supra, involves the reaction of specific blocked alkyl
amine aldehydes with polyvinyl aicohol or polyvinyl alcohol copolymers to produce ammo
functional poiwinvl alcohols. Blocked alky 1 aldehydes include 4-amino butyral dimethyl acetal
and ether aikyl acetals which react with polyvinyl to produce the 4-amino alkylal of
polyvinyl alcohol, e.g.. the 4-aminobutryral of polyvinyl alcohol.
The incorporation of primary amine functionality in the amine functional polyvinyl
alcohol, e.g.. hvdrolvzed vinyl acetate N-vinylfom amide or hydrolyzed vinyl acetate allyl amine
copolvmers or polyvml alcohol aminobutyral polymers is within the range of from about 1 to
amounts of up to about 30. preferablv about 5 to 20 mole%. The desired level of vinyl acetate
conversion to vinyl alcohol is from about 75 to 100%. preferably from about SO to 99%
hvdrolvsis ana the level of vinylarnide conversion to vinylamine is from about 25 to fully
hvdrolvzed. e.g.. about 100%.. In some preferred embodiments the hydroiyzed vinyl acetate is
present in an amount of from about SO to 95 moie percent.
The following sets forth operati\e and preferred ranges regarding the use of an amine
functional polyvinvl alcohol. It is understood that the values identnied are "about" or
approximate ranges.
Operative and Preferred Ranges of the Composition:
Primary Amine functional PVOH
Molecular weight (wt. average)
Primary Amine Content
Acetate Hydrolysis
wt. % binder in ink jet coating
Coaling pH
Ink Jet coating formulations typically incorporate silica pigment and possibly a small
amount of another mineral pigment in the formulation. Typically, the mineral pigment is silica
and is incorporated in the ink jet coating formulation in amounts which range from about I to
90%. preferably about 30 to 85%. by weight. The level of binder (solids basis) will range within
conventional levels or about 20 to 80% by weight of the ink jet formulation. The levels of
pigment and binder depend significantly upon the type of coater used in the preparation of the
ink jet paper. Synthetic aluminum silicates having surface areas of about 100 nr per gram as
well as clay. talc, calcium carbonate, magnesium silicate and the like have been used as fillers m
ink jet coating compositions and can be used. the preferred filler for ink jet coating
compositions is silica having a surface area of about 50 to 700 nr gram. Ink iet formulations
may also contain conventional additives such as defoamers. surface acme agents, dyes,
ultraviolet absorbents, pigment dispersants. moid inhibitors, thickeners and water-resisting
agents.
The ink jet formulation usually is applied to the paper surface in amounts ranging from
about 2 to 20 grams per nr . Coat weight is somewhat dependent upon the type of coating
applicator. The ink iet coating incorporating the amine functional poiyvinyl alcohol is supplied
to the paper surface itself rather than to paper stock prior to sheet formation.
Not intending to be bound by theory, it is believed the amine group in the amine
functional polymers provides a cationic charge on the paper surface which reacts with the
anlonio sulfonie acid groups of the direct or acid dye of the ink jet inks to form an insoiuble sail.
By forming an insoluble salt, the inks become waterast on the paper surface and the
ligitfastness is improved in those paper products incorporating the amine functional polyvinyl
alcohol as compared to ink iet coatings incorporating poly(vinyl alcohol) nomopol"ymer as the
binder. Pigment binding strength, and silica pigmem binding strength in particular, is improved
with the use of the ink jet coatings incorporating the amine functional poiy(vinyl alcohol)
polymers in comparison to the ink jet coalings incorporating the po!y(vinyl alcohol)
homopolymer due to the strong absorption of the amines with the silanol group on the silica
pigment.
The following examples are provided to illustrate the preparation of suitable aminc
functional polyvinyl alcohols and to illustrate ink jet coating systems for paper.
Example 1
Procedure for Forming Primary Amine Functional Polvvinvl Alcohols
A poly(vinyl alcohol/vinyl amine) copclyrner herein referred to as PYOH/PVNH2 (6
mole% vinyl aminel was prepared by first polymerizing a vinyl acetate/N-vinylformamide (94/6
molar copolymer in methanol by free radical polymerization procedures. The vinyl acetate, N-
vinyl formamide copolymer was hydrolyzed to a vinyl alcohol/N-vinylfonnamide copolymer by
alkali saponification of vinyl acetate using 0. i molar sodium methoxide in methanol. The vinyl
alcohol N-vilnylformannae copohmer was by droiyzed to a vinyl aicohoi vinyl amine-HCl
copolymer by heating at 90 C for 6 hours in distilled water to which concentrated HCl was
added. The product was precipitated using methanol and then dried in a vacuum oven. The
average molecular weight of the PYOH PVNH2- copolymer was about 95.000 ( Mwt. the percent
bydrolysis ot the acetate was 100% and the percent hydrolysis of the X-vinylformamide was
100%.
A second poly (vinyl alcohol vinyl amine) copolymer (PYOH PVNH2) ( 12 mole% vinvl
amine) was prepared by first polymerizing a vitny1 acetate N-vinylformamide (88 12 molar)
copolymer in. methanol by free radical polymerization procedures. The molecular weight of the
PV"OH PVNH, copolymer was 96.000. the percent hydrohsis of the acetate was 100% and the
percent bydrolysis of the N-vinylformamide was 100%.
Example 2
Procedure for Producing Priman Amine Functional Poly vinyl Alcohol
1.sing --Ammo But- aldeinde Dimethylacetal 12 mole % anmine)
Poly vinyl) 1 aicohol ( Airvol 100 was dissoilved in water (270 ml) at 700C under N2.
Alter dissolution, concentrated hydrochloric acid (1 6.34g. 0.1 70 mole) and 4-
aminobuiyruldehyde dimethyl acctal (ABAA) (18.14g. 0.136 mole) were added to the reaction
along with additional water (20 ml). The reaction was continued at 750C for 6 hours and cooled
to room temperature. The polymer product was isolated by precipitation in acetone, washed with
further acetone and dried in a vacuum oven (600C/l torr)". The composition of the resultant
polymer as determined by 13"C NMR. was 12% mole % 4-aminobutyral incorporation.
Example 3
Coating Adhesive Strength
Several silica pigmented coatings were prepared in conventional manner for the purpose
of evaluating coating adhesive strength, one type incorporating a polyvinyl alcohol homopolymer
and the other type incorporating a PVOH/PVNH2 copolymer as the binder. The coatings were
formulated with 100 parts precipitated silica pigment and 40 pans of Airvol 125 polyvinyl
alcohol (A 125) in the one case and an ainine functional polyvinyl alcohol of the type in
Example 1 having 12 mole% amine MMW PVOH/PVNH2 in the other case and then applied to
the paper at a coating weight of approximately 6 grams m2 . In preparing the coatings the
polyvinyl alcohol was solubilized in water to a concentration of about 10% solids by weight.
The pigment was ther. added. The testing was performed on an IGT model AIC2-5 following
T.APPI procedure T514. The larger the value, the greater the coating strength. Table 1 sets forth
conditions and results.
Table 1
1GT Pick Strength of Coating Containing
PVOH Homopolymer and PVOHPVNH2 Copolymer
Sample Identification IGT Pick Strength
40 pans A125 (99.3% hydrolysis MMW PVOH1 ) 6..5
40 pans 12 mole % MMW PVOH PVNH2 7.83
"MMW PVOH refers to medium molecular weight or weight average molecular weight of
approximateb, 110.000
2MMW PVOH NH2 refers to medium moiecular weignr or weigni average molecular weight of
approximately 06.000.
The results show the vin\! alcohol vinyl amine copolymer containing 12 molar%
hydrolyzcd N-vinylformamide gave higher pick strengths than the PVOH homopoly mer. thus
showing the enhanced binding properties of the ink jet coating due to the presence of the pamary
amine.
Example 4
Printed Ink Optical Density
Sheets of uncoated base sheet were coated for the purpose of evaluating ink jet optical
density. Several colors were evaluated. One set of base sheets was coated with an ink jet
coating comprising PYOH and silica pigment and another set was coated with an ink jet coaling
comprising 6 mole% MMW PVOH/PVNH2 and silica pigment coating using a Meyer Rod
drawn down bar. The level of binder was varied from 70 weight parts to 30 weight pans per 100
weight parts silica. Coat weight was in the range of 4 to 6 grams"m2. After coating and drying,
the sheets were printed with an Hewlett Packard 560 ink jet printer using an HP test pattern
distributed by Hewlett Packard for the purpose of testing ink jet paper media. After printing the
samples were measured for optical density using a Tobias IQ 200 Reflection Densitometer.
Figures 1 through 5 compare the ink optical density of the ink jet coatings comprising
PYOH PY\H: copolymer binder versus the ink jet coatings comprising the standard PYOH
binder. In the Figures:
* 100% PYOH means that no silica was incorporated into the ink jet coating formulation.
Airvol 125 polyvinyl alcohol is 99.3% hydrolyzed and has a molecular weight (Mw) of
100.000.
Airvo! 325 polyvinyl alcohol is 98.0% hydrolyzed and has a molecular weight (Mw) of
110.000.
Airvol 523 poiyvinyl alcohol is 88.0% hvdrolyzed and has a molecular weight (Mw) of
110.000.
PYOH PVAm is another abbreviation for PYOH PVNH2 the amine functional poiyvmyl
alcohol of Example 1.
Figure 1 shows thai monochrome ink jet optical density for the paper naving the ink jet
coating incorporating the PVOH PV NH2 binder was superior to the paper having the ink jet
coating incorporating the poiyvinyl alcohol in all cases except at the highest loading. On the
other hand, the PYOH "PVNH2 based coating remained essentially constant at al levels
Figure 2 shows that a: low levels of binder to silica, the PYOH Vam was superior to the
PYOH thus showing enhanced binding strength.
Figure 3 compares the magenta optical density achieved with the various coatings and
particularly that the PVOH VA\m eopolymer was superior in about every category to the PVOH
and especially at the low binder t to pigment levels.
It may be seen in Figure 4 that the poivinyl alcohol polyviny lamine binder was
significant!} better in performance vis-a-vis PYOH in the yellow optical density test. In contrast
to the previons optical density test, substantially superior results were obtained with the amine
functional polyvinyl alcohol at all levels.
It is seen in Figure 5 that comparable results were obtained with the PYOH"YAm binder
at high loadings but greater properties at the lower loading.
Example 5
Waterfastness
The waterfastness of inks printed onto a paper coated with an ink jet coating
incorporating PVOH/PVNH2 as the binder was compared to paper coated with the ink jet coating
incorporating the PVOH homonolymer. The test was performed by first measuring the
monochrome black ink density after printing. The printed area was then immersed in distilled
water for 30 seconds ana dried on a hot plate under tension. The optical density was then
measured again The results are set forth in Table -2.
Table 2
Watcrfasmess on Ink Jet Paper
Coated With PVOH and PVOH"PVNH2, Binders
? Represents the Difference in Optical Density
Between Pre Wet and Post Wet Paper Products
Table 2 shows that the waterfasmess of printed inks is improved when the printing is
effected omo a paper product having a silica based ink jet coating which incorporates the amine
functional polyvinyi alcohol. As a binder, these results show that the loss in optical density after
wetting decreases as the level of 6 mole%( PVOH"PVNH2 was increased in the coaling. These
results also show that the ink jet coating incorporating the 12 moie% PVOH PVNH2- provides
improved waterfastness as compared to the 6 rnoie°o PVOH"PVNH2;. copoiymer a: approximately
equal addition levels.
Example 6
Rheology of ink let coatings
Several ink jet coating formulations were prepared using different binders to determine
their effect on the rheology of the resulting ink jet formulations. The graph (Fiiune 6)
demonstrates the shear vs. visoosity response for a 13% solids coating formulated with 100 parts
silica and 40 parts binder. Four hinder types were used and they are:
1. Fully hydrolyzed medium molecular weight PVOH (FH MMW) the molecular
weight was approximately 110.000.
2. Pan-ally hydrolyzed medium molecular weight PVOH (PHNH2 MMW) the
molecular weight was approximate!) 110.000.
3. PVOH/ PVNH2 medium molecular weight 6 mole%. HC1 salt): the molecular weight
was approximately 95.000.
4. PYOH"PVNH2 medium molecular weight 12 mole % free base: the molecular
weight was approximately 96.000.
The shear viscosity of the coatings was measured with an ACAV High Shear Capillary
Visoometer at temperatures of 35 100C
The results in Figure 6 show that the silica based Ink Jet coatings incorporating the
polyvinyl alcohol) vinyl amine ecpolymer binders produce a much lower viscosin response as
compared to ink jet coatings incorporating poly vinyl alcohol) homopolymer as the binder. The
mechanism for the reduced viscosity response to high shear is not known but may relate to the
hish absorption of the amine functional PVOH onto the surface of the silica pigment. It is
believed a greater absorption of the copolymer onto the surface of the silica would prevent the
Polymer chains from extending into the liquid phase of the coating thereby lowering the overall
iscosity of the coating. The data also supports the view that the greater the amine content in the
binder, the greater the absorption and the lower the snear thickening response.
Example 7
Lighfastness
Several ink jet formulations were prepared for the purpose of determining the
itghtfastness of the formulations The following table demonstrates the UV hghtfasiness of ink
jet primed sheets with coatings based on 100 parts precipitated siiice pigment. Lignvfasiness was
determined by measuring the optical density of ink jet printed papers before and after exposure
54 hour UV light exposure. The optical densities of the paper were measured with a Tobias IQ
200 Reflection Denshometer. The printed sheet then was exposed to UV light usinu a Q-U-V
Accelerated Weathering Tester. The \alues were recorded and set forth in Table 5. ? represents
the difference in optical density between the initial and exposed samples, the lower the value, the
better the lightfastness.
The results show that the lightfastness of ink jet primed colors improved when the
PYOH PVNH2- copolymer was used as a binder for the ink jet coating compared to when PVOH
hornopohmer was used as the binder for ink jet coatings. Lightfastness also improved with
increased PVOH PVNH2 binder level in the coating as well as with increased amine content in
the copolymer backbone. The mechanism for improved lightestness is not understood but may
be due an increased light stability of the salt complex formed between the sulfonic acid groups of
the dyes used in the inks and the amine in the amine functional polyvinyl alcohol.
Example 8
Dry Time
Ink Jet coating formulations were prepared which vary in the % hydrolysis ol the various
PVOH binders and compared for ink dry time (the time it lakes the ink to dry after printing from
an ink jet primer) to a similar formulation which contained a 12 mole% medium molecular
weight PVOH"PYAm binder. The coating consisted of a 100 parts precipitated silica pigment
with 40 parts of the PVOH or PVOHPVAm binder prepared at a total solids level of 15% The
formulations were Meyer Rod coated on to an base paper at coat weights between 7 and S
grams square meter.
The coated papers were tested for ink dry time according to procedures outlined in the
"Hewlett Packard Paper Acceptance Criteria For HP Deskjet 500C. 550C & 560C Printers".
Results are shown in Figure 7. wherein:
PH MMW refers to 87% hydrolysis at approximately 110.000 average molecular weight-.:
1H MMW refers to 96% hydrolysis at approximately 110.000 average molecular weight
SH MMW refers to 87% hydrolysis at approximately 110.000 average molecular weight:
and
PVOH"PVAm refers to 12 mole% vinyl amine at 95.000 average molecular weight.
Figure7 demonstrates the improved dry time of the ink jet formulations containing
PYOH PVAm versus the formulations containing the PVOH homopolymer.
Example 9
Ink Jet Impregnated Paper Product
Paper products were prepared in accordance with the general procedure of US Patent
4.880.497 in that the paper product was impregnated with the binder prior to coating rather than
being applied the surface of the paper as a coating. The obiective was to determine whether
comparable ink jet; properties could be achieved by impregnation, vis-a-vis coating, in addition
to improving the paper"s wet and dry strength.
As a second objective. me amine functional poiyvmyl alcohol, viz., hydrolyzed vinyl
acetate n-vinyiformaniide was replaced and a commercial quaternized poiyvinyl alcohol
substituted therefor.
Paper products were prepared by adding the aqueous binder to a paper substrate a! the
size press as opposed to applying the binder 10 the surface of" the paper as a paper coaling. Three
methods were employed as follows:
1. Three base sheets were prepared, one haying no coating. another coated with
polyvinyl alcohol and another coated with amine functional polyvinyl alcohol.
Silica was bound to the paper via the binder": no silica was employed in the absence
of the binder.
2. Three base sheets were prepared in accordance with 1 above except the paper was
surface sized (impregnated ) with polyvinyl alcohol prior to coating w ith pol\ vinyl
alcohol or amine functional polyvinyl alcohol.
3. Three base sheets were prepared n accordance with 2 above except the paper was
surface sized with the amine functional polyvinyl alcohol prior to coating with the
respective binders. The results are set forth in Figures 8. 9 and 10.
Results Summary
Surface sizing a paper substrate with 12 mole % medium molecular weight PYOH YAm
provided improved levels of optical density (one measure of ink jet printability) in comparison to
sheets surfaced sized with Airvol 523 homopolymer and the non surface sized base sheet
(Figure 8). However, the results show that by applying the binder as a coating as opposed to
impregnation, the ink jet printing quality is enhanced substantial!}-. There appears to be little
difference between the optical density in o PVOH PVNH2 coated paper and a PVOH "PV NH2
impregnated and coated paper. Ink waterfastness of the three papers was very similar (see
Figure 9). Airvol 523 polyvinyl aicohol surface sized sheets provided a higher level of paper
drv strength in comparison to the PVOH VAm. Both surface size sheets provided strength
greater than the base sheet.
Example 10
This example provides a comparison between ink jet papers coated with a PVOH "PVNH2
aqueous binder and one coated with a eationic polyvinyl aicohoi sold by K.uraray as canonic
polymer. C506. The results are shown in Figures 11 and 12.
Fieure 11 show-s that coating the base sheet with a coating containing 100 cans of silica
pigment and 40 parts of PVOH VAm; provided le. eis of ink optical density which were much
greater than coatings containing 1 00 pans of sihea pigment with either 40 pans of Airvol 523 or
40 parts of thc Kuriaray cationic polymer. C506. -Ml coaled papers provided levels of optical
density which were greater than sheets which were surface sized only. Figure 12 shows that ink
waterfastness was excellent with the PVOH/V"Am coating and very poor with the Airvol 523
poiyvinyl alcohol and the Kuraray cationic polyvinyl alcohol. Dry strength of all coated sheets
were approximately equal to each other and slightly greater than the base sheet. The coated
sheets were much lower in dry strength as compared to the surface sized sheets.
Example 1 1
Ink Jet Paper Using
4-amino butyral derivative of Polyyinyl Alcohol
The procedure of Example 2 to make a 4-aminobutyral derivative of poly vinyl alcohol
was followed except the polymer contained 7 mole% amine functionality. It was compared to
polvvinvl alcohol as a binder and to other amine functional alcohols derived by the hydrolysis of
a vinyl acetate-N-vinyl formamide copoiymer having the mole% amine functionality set forth.
Figure 13 sets forth the results.
The results show each of the amine functional polyvinyl alcohols were superior to
polyviny1 alcohol. The table also shows that the 7% amine functionality was equivalent to the 12
and 18% mole functional bydrolyzed vinyl acetate N-vinyl formamide polymer systems.
In summary, the amine functional polyvinyl alcohols provide excellent properties to ink
jet coatings for paper products and particularl; those ink iet coatings based upon silica. In
almost every case the properties were improved vis-a-vis polyvinyl alcohol. When comparing
the polyviny] alcohol polyvmyl amine binders, the 12 moie% amine was superior to 6 moie%
amine. This is believed evidence that the amine provides cationic sites on the poiymer backbone
which react with the inks from the ink jet printer to improve the ink optical density ink
waterfastness. and ink light stabilitv. The greater the amine content, the greater rhe
improvements. The amine group also contributes to the binding power of the binder and silica.
It is also observed that the 4-aminobutyral derivative of polyvinyi alcohol affords slightly
superior results to the hydrolyzed vinyl acetate N-vinylformamide polymers. This is believed
due to the fact that the primary amine groups are in the form of extended side chains pendent
from the poiymer backbone wherein the hydroivzed N-vinyl formamide groups are closely bound
to the poivmer backbone. It is believed the side chains allow the amine cationic site better
access to the inks and also allows the amine to more easily combine with the sihea.
WE CLAIM:
An ink jet printing paper product having applied to
its surface an ink jet coating formulation
comprising a mineral pigment and an aqueous based
polymeric binder applied to its surface, the
improvement which comprises incorporating a primary
amine functional polyvinyl alcohol as the polymeric
binder, said primary amine functional polyvinyl
alcohol being selected from the group consisting of
a hydrolyzed copolymer of vinyl acetate and N-vinyl
amide, a hydrolyzed copolymer of vinyl acetate and
allyl amine, and an aminoallcylal derivative of
polyvinyl alcohol.
The paper product as claimed in Claim 1 wherein the
mineral pigment is silica.
The paper product as claimed in Claim 1 wherein the
primary amine functionality in said amine functional
polyvinyl alcohol is from 1 to 30 mole percent.
The paper product as claimed in Claim 1, wherein the
primary atnine functional polyvinyl alcohol is an
arainoalkylal derivative of polyvinyl alcohol.
The paper product as claimed in Claim 5, wherain the
primary amine functional polyvinyl alcohol is the 4-
aminobutyral of polyvinyl alcohol.
The paper product as claimed in Claim 1, wherein the
primary amine functional polyvinyl alcohol is a
hydrolyzed copolymer of vinyl acetate and allyl
amine.
The paper product as claimed in Claim 1, wherein
the primary amine functional polyvinyl alcohol is a
hydrolyzed copolymer of vinyl acetate N-vinylamide.
The paper product as claimed in Claim 7 wherein said
N-vinylamide is N-vinylformamide.
The paper product as claimed in claim 8, wherein
said N-vinylamide is N-vinylacetamide.
The paper product as claimed in Claim 1 wherein the
silica is present in an amount of from 30 to 85% by
weight of the ink jet coating formulation.
The paper product as claimed in Claim 10 wherein the
ink jet coating formulation is applied to the
surface in an amount of from 2 to 20 grams per m2.
The paper product as claimed in Claim 11 wherein the
binder is incorporated into the ink jet coating
formulation in an amount of from 20 to 60% by
weight.
The paper product as claimed in claim 11 wherein the
copolymer polyvinyl alcohol and polyvinyl amine
polymer is a hydrolyzed copolymer of vinyl acetate
and N-vinylamide.
The paper product as claimed in Claim 12 wherein the
hydrolyzed copolymer consists essentially of
hydrolyzed vinyl acetate and N-vinyl formamide • and
the hydrolyzed vinyl acetate is present in an amount
from 80 to 95 mole percent.
The paper product as claimed in Claim 11 wherein the
amine functional polyvinyl alcohol is the 4-
aminobutyral of polyvinyl alcohol.
The paper product as claimed in Claim 11 wherein the
amine functional polyvinyl alcohol is a hydrolyzed
copolymer of vinyl acetate and allyl amine.
In a process for preparing an ink jet recording
sheet which comprises applying an ink jet coating to
a paper substrate, said ink jet coating comprising a
polymeric binder and a mineral pigment, the
improvement which comprises utilizing a primary
amine functional polyvinyl alcohol as the polymeric
binder, said primary amine functional polyvinyl
alcohol being selected from the group consisting of
a hydrolyzed copolymer of vinyl acetate and N-vinyl
amide, a hydrolyzed copolymer of vinyl acetate and
allyl amine, and an aminoalkylal derivative of
polyvinyl alcohol.
The process as claimed in Claim 17 wherein the
mineral pigment is silica.
The process as claimed in claim 18 wherein the
primary amine functionality in said amine functional
polyvinyl alcohol is from 1 to 30 mole percent.
The process as claimed in Claim 18 wherein the
silica is present in an amount of from 30 to 85% by
weight of the ink jet coating formulation.
The process as claimed in Claim 20 wherein the ink
jet coating formulation is applied to the surface in
an amount of from 2 to 20 grams per m2.
The process as claimed in claim 21 wherein the
binder is incorporated into the ink jet coating
formulation in an amount of from 20 to 60% by
weight.
The process as claimed in claim 22 wherein the
copolymer polyvinyl alcohol and polyvinyl amine
polymer is a hydrolyzed copolymer of vinyl acetate
and N-vinylamide.
The process as claimed in claim 23 wherein the
hydrolyzed copolymer consists essentially of
hydrolyzed vinyl acetate and N-vinyl formamide and
the hydrolyzed vinyl acetate is present in amount
from 80 to 95 mole percent.
This imention relates to an improvement in coalings particularly suited lor the
preparation of paper productshaving an ink jet coating applied thereto and to the resulting paper
products. The improvement in ink jet coalings resides in the incorporation of a primary amme
functional polyvinyl alcohol (PVOH/PVNH2) as a polymeric binder. One form of an amine
functional polyvinyl alcohol is produced by the hydrolysis of a copolymer of vinyl acetate and N-
vinylformamide or vinyl acetate and allyl amine. Another is the polyvinyl butyral derivative of
polyvinvl alcohol which typically is formed by the reaction of a 4-amino alkyl
aldehyde dialkyl acetal. such as 4-aminobutyraldehyde dimethyl acetal with
polyvinyl alcohol.

Documents:

1039-kolnp-2003-granted-abstract.pdf

1039-kolnp-2003-granted-claims.pdf

1039-kolnp-2003-granted-correspondence.pdf

1039-kolnp-2003-granted-description (complete).pdf

1039-kolnp-2003-granted-drawings.pdf

1039-kolnp-2003-granted-form 1.pdf

1039-kolnp-2003-granted-form 18.pdf

1039-kolnp-2003-granted-form 2.pdf

1039-kolnp-2003-granted-form 3.pdf

1039-kolnp-2003-granted-form 5.pdf

1039-kolnp-2003-granted-letter patent.pdf

1039-kolnp-2003-granted-pa.pdf

1039-kolnp-2003-granted-reply to examination report.pdf

1039-kolnp-2003-granted-specification.pdf

1039-kolnp-2003-granted-translated copy of priority document.pdf

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Patent Number

219062

Indian Patent Application Number

01039/KOLNP/2003

PG Journal Number

17/2008

Publication Date

25-Apr-2008

Grant Date

23-Apr-2008

Date of Filing

14-Aug-2003

Name of Patentee

CELANESE INTERNATIONAL CORPORATION

Applicant Address

1601 WEST LBJ FREEWAY, DALLAS, TX 75234 USA.

Inventors:

#	Inventor's Name	Inventor's Address
1	BOYLAN JOHN RICHASRD	3235 ALTONAH ROAD BETHLEHEM PA 18017, USA

PCT International Classification Number

B61

PCT International Application Number

PCT/US02/06544

PCT International Filing date

2002-03-05

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	09/802,091	2001-03-08	U.S.A.