Indian Patents. 270136:ROTOMOLDING PROCESS USING SECONDARY STERICALLY HINDERED AMINES AS ADDITIVES

Title of Invention	ROTOMOLDING PROCESS USING SECONDARY STERICALLY HINDERED AMINES AS ADDITIVES
Abstract	The instant invention pertains to the use of secondary sterically hindered amines as processing additives in rotational molding processes. These additives increase process stability, since they provide a broader temperature range towards higher temperatures during the melt processing step.

Full Text	Use of Secondary Stericallv Hindered Amines as Processing Additives in Rotomoldina Processes The instant invention pertains to the use of secondary sterically hindered amines as processing additives in rotational molding processes. These additives increase process ^ stabihty, since they provide a broader temperature range towards higher temperatures during the melt processing step. Rotational molding is a highly versatile manufacturing option that allows for unhmited design possibihties with the added benefit of low production costs. The rotational molding process (rotomolding process) starts with a good quahty mold that is placed in a molding machine that has a loading, heating, and coohng area. Several molds may be placed on the machine at the same time. Pre-measured plastic resin is loaded into each mold, and then the molds are moved into the oven where they are slowly rotated on both the vertical and horizontal axis. The melting resin sticks to the hot mold and coats every surface evenly. The mold continues to rotate during the coohng cycle so the parts retain an even wall thickness. Once the parts are cooled, they are released from the mold. The rotational speed, heating and coohng times may be all controlled throughout the process. Rotational molding offers design advantages over other molding processes. With proper design, parts that are assembled from several pieces can be molded as one part, ehminating expensive fabrication costs. The process also has a number of inherent design strengths, such as consistent wall thickness and strong outside corners that are virtually stress free. If additional strength is required, reinforcing ribs can be designed into the part. Rotational molding dehvers the product the designer envisions. Designers can select the best material for their apphcation, including materials that meet FDA requirements. Additives to help make the part weather resistant, flame retardant, or static free can be specified. And because parts are formed with heat and rotation, rather than pressure, molds don't need to be engineered to withstand the high pressure of injection molding. Production costs for product conversions are reduced because hghtweight plastics replace heavier, often more costly materials, which makes rotational molding as cost effective for one-of-a-kind prototypes as it is for large production runs Rotational molding is versatile and able to handle a vast variety of shapes and sizes. Many parts cannot be readily produced by any other method. Typical examples are specialty tanks and containers for fuel, water, and chemical processing, hvestock feeders, drainage systems, food service containers, instrument housings, vending machines, highway barriers and road markers. Other apphcation areas are consumer products, toys and transportation. Many aspects of the rotational molding process are, for example, described by R. J. Crawford and J. L. Throne in Rotational Molding Technology, Plastics Design hbrary, Wilham Andrew Pubhshing, 2001. As mentioned above rotational speed, heating and coohng times may be all controlled throughout the process. The maximum temperature of the air, which is reached inside the hollow molded article, depends strongly on the heating time. This temperature is also called peak internal air temperature (PIAT). It correlates with the temperature of the molten resin. The concept of peak internal air temperature (PIAT) and the consequences, if a too low or too high PIAT is apphed, is for example described by M. C. Cramez et al. in Proc. Instn Mech. Engrs. Vol. 217 Part B: J. of Engineering Manufacture, 2003. The peak internal air temperature can influence the final properties of the molded product. For example, if the temperature becomes too high, a strong yellowing may occur and also the mechanical properties are negatively affected, for example, the impact strength decreases significantly. If the temperature remains too low the final properties can also be adversely affected because the resins have not been properly molten. In other words, there is only a small temperature range for achieving the desired final properties. It is therefore of high interest to widen this temperature range or processing window, within which almost constant mechanical properties are obtained. Botkin et al in "An additive approach to cycle time reduction in rotational molding" Rotational Molding by Design Conference, Society of Plastics Engineers, 2004 have demonstrated that by using a proprietary process stabihzer, the PIAT can be shifted towards lower temperatures maintaining good impact strength. This con-esponds to broadening the processing window towards lower temperatures. Surprisingly it has now been found that when a secondary hindered amine compound is added to the resin formulation a significantly broader processing window towards higher temperatures is achieved without adversely affecting color and mechanical properties of the molded article. Consequently one aspect of the invention is the use of a secondary stericahy hindered amine compound as processing additive for enlarging the processing window towards higher peak internal air temperatures in rotational molding processes of thermoplastic polymers. Under processing window there Is understood the temperature range, as measured by the peak internal air method (PIAT), within which the mechanical properties and/or the color of the molded article remain essentially the same. A particularly suitable mechanical property to measure is impact strength, for example at low temperatures. Low temperature means in this context from 0° to -50° C, particularly -20° C to -40° C. Preferred are the following commercial compounds. Chimassorb 2020®, Chlmassorb 944®, Tinuvin 770® and Tinuvin 783®, Cyasorb UV 3346®, Cyasorb UV 3581®, Dastib 845®, Dastib 1082®, Diacetam 5, Fero 806-X®, Goodrlte 3034®, Goodrite 3150®, HALS IC-TAM, Hostavin N 20®, Hostavin N 24®, Hostavin N 30®, Huls S-95®, ICI PA 500®, hchtschutzstoff UV 31, Luchem HA-B 18®, Mark LA 55®, Mark LA 57®, Mark LA 67®, Mark LA 68®, Sanduvor 3050®, Sumillzer 61®, Sumillzer 70®, Suimisorb TM 61®, UVASORB HA 88®, Uvinul 4049®, Uvlnul 5050®, Uvasll 299®, Uvasil 125®. These compounds are commercially available and described In: US-A-5,679,733, US-A-3,640,928, US-A-5,204,473, US-A-4,619,958, US-A-4,110,306, US-A-4,110,334, US-A-4,689,416, US-A-4,408,051, SU-A-768,175 (Denwent 88-138,751/20), US-A-5,049,604, US- A-4,769,457, US-A-4,356,307, US-A-4,619,956, US-A-5,182,390, GB-A-2,269,819, US-A-4,292,240, US-A-5,026,849, US-A-5,071,981, US-A-4,547,538, US-A-4,976,889, US-A-4,086,204, US-A-6,046,304, US-A-4,331,586, US-A-4,108,829, US-A-5,051,458, WO-A-94/12,544 (Derwent 94-177,274/22), DD-A-262,439 (Derwent 89-122,983/17), US-A-4,857,595, US-A-4,529,760, US-A-4,477,615 (CAS 136,504-96-6), US-A-4,340,534, WO-A-98/51,690, EP-A-1,803, the disclosures of which are incorporated by reference, The sterically hindered amine compound according to the invention is preferably added in an amount from 0.01 to 5%, more preferably from 0.05 to 2% and most preferably from 0.1 to 1 % by weight, based on the weight of the thermoplastic polymer. For instance the thermoplastic polymer is a polyolefin, a polyvinylchloride or a polyamide. Examples are given below. 1. Polymers of monoolefins and diolefins, for example polypropylene, polyisobutylene, po-lybut-1-ene, poly-4-methylpent-1-ene, polyvinylcyclohexane, polyisoprene or polybutadiene, as well as polymers of cycloolefins, for instance of cyclopentene or norbornene, polyethylene (which optionally can be crosshnked), for example high density polyethylene (HOPE), high density and high molecular weight polyethylene (HDPE-HMW), high density and ultrahigh molecular weight polyethylene (HDPE-UHMW), medium density polyethylene (MDPE), low density polyethylene (LDPE), hnear low density polyethylene (LLDPE), (VLDPE) and (ULDPE). Polyolefins, i.e. the polymers of monoolefins exemphfied in the preceding paragraph, prefe¬rably polyethylene and polypropylene, can be prepared by different, and especially by the following, methods: a) radical polymerisation (normally under high pressure and at elevated temperature). b) catalytic polymerisation using a catalyst that normally contains one or more than one metal of groups IVb, Vb, VIb or VIII of the Periodic Table. These metals usually have one or more than one hgand, typically oxides, hahdes, alcoholates, esters, ethers, amines, alkyls, alkenyls and/or aryls that may be either n- or a-coordinated. These metal complexes may be in the free form or fixed on substrates, typically on activated magnesium chloride, titanium(lll) chloride, alumina or sihcon oxide. These catalysts may be soluble or insoluble in the polymerisation medium. The catalysts can be used by themselves in the polymerisation or further activators may be used, typically metal alkyls, metal hydrides, metal alkyl hahdes, metal alkyl oxides or metal alkyloxanes, said metals being elements of groups la, lla and/or Iha of the Periodic Table. The activators may be modified conveniently with further ester, ether, amine or silyl ether groups. These catalyst systems are usually termed Philhps, Standard Oil Indiana, Ziegler (-Natta), TNZ (DuPont), metallocene or single site catalysts (SSC). 2. Mixtures of the polymers mentioned under 1), for example mixtures of polypropylene with polyisobutylene, polypropylene with polyethylene (for example PP/HDPE, PP/LDPE) and mixtures of different types of polyethylene (for example LDPE/HDPE). 3. Copolymers of monoolefins and diolefins with each other or with other vinyl monomers, for example ethylene/propylene copolymers, hnear low density polyethylene (LLDPE) and mixtures thereof with low density polyethylene (LDPE), propylene/but-1-ene copolymers, propylene/isobutylene copolymers, ethylene/but-1-ene copolymers, ethylene/hexene copo¬lymers, ethylene/methylpentene copolymers, ethylene/heptene copolymers, ethylene/octene copolymers, ethylene/vinylcyclohexane copolymers, ethylene/cycloolefin copolymers (e.g. ethylene/norbornene hke COC), ethylene/1-olefins copolymers, where the 1-olefin is gene¬rated in-situ; propylene/butadiene copolymers, isobutylene/isoprene copolymers, ethylene/vi-nylcyclohexene copolymers, ethylene/alkyi acrylate copolymers, ethylene/alkyi methacrylate copolymers, ethylene/vinyl acetate copolymers or ethylene/acryhc acid copolymers and their salts (ionomers) as well as terpolymers of ethylene with propylene and a diene such as hexadiene, dicyclopentadiene or ethyhdene-norbornene; and mixtures of such copolymers with one another and with polymers mentioned in 1) above, for example polypropylene/ethy-lene-propylene copolymers, LDPE/ethylene-vinyl acetate copolymers (EVA), LDPE/ethylene-acryhc acid copolymers (EAA), LLDPE/EVA, LLDPE/EAA and alternating or random polyal-kylene/carbon monoxide copolymers and mixtures thereof with other polymers, for example polyamides. 4. Polyamides and copolyamides derived from diamines and dicarboxyhc acids and/or from aminocarboxyhc acids or the corresponding lactams, for example polyamide 4, polyamide 6, polyamide 6/6, 6/10, 6/9, 6/12, 4/6, 12/12, polyamide 11, polyamide 12, aromatic polyamides starting from m-xylene diamine and adipic acid; polyamides prepared from hexamethylenediamine and isophthahc or/and terephtlnahc acid and with or without an ela¬stomer as modifier, for example poly-2,4,4,-trimethylhexamethylene terephthalamide or poly-m-phenylene isophthalamide; and also block copolymers of the aforementioned polyamides with poiyolefins, olefin copolymers, ionomers or chemically bonded or grafted elastomers; or with polyethers, e.g. with polyethylene glycol, polypropylene glycol or polytetramethylene glycol; as well as polyamides or copolyamides modified with EPDI\/I or ABS; and polyamides condensed during processing (Rll\/I polyamide systems). Particular preference is given to polyethylene preferably hnear low density polyethylene (LLDPE). For example the peak internal air temperature range in rotational molding processes is enlarged up to 10 to 50° C, preferably up to 15 to 40° C towards higher temperatures. The reference being without the addition of a sterically hindered amine. Preferably the peak internal air temperature range is from 210 to 250° C, more preferably from 215 to 250° C and most preferably from 220 to 250° C. The above temperature range corresponds to the preferred processing window, within which the mechanical properties and/or the color of the article are not adversely affected. In a specific embodiment of the invention an additional stabihzer selected from the group consisting of a UV-absorber, a sterically hindered amine, different from that of formula (I) or (II), a phenohc antioxidant, a phosphite or phosphonite and a benzofuranone or indohnone is present. Examples for the above mentioned additives are given below. 1. Antioxidants 1.1. Alkviated monophenols. for example 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-di-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-bu-tyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, 2-(a-methylcyclohexyl)-4,6-dimethyl- phenol, 2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-di-tert-butyl-4-meth-oxymethylphenol, nonylphenols which are hnear or branched in the side chains, for example, 2,6-di-nonyl-4-methylphenol, 2,4-dimethyl-6-(1'-methylundec-1'-yl)phenol, 2,4-dimethyl-6-(1'-methylheptadec-1'-yl)phenol, 2,4-dimethyl-6-(r-methyltridec-r-yl)phenol and mixtures there¬of. 1.2. AlkvlthiomethvlDhenols. for example 2,4-dioctylthiomethyl-6-tert-butylpheno!, 2,4-dloctyl-thiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-ethylphenol, 2,6-di-dodecylthiomethyl-4-nonylphenol. 1.3. Hvdroquinones and alkylated hvdroquinones. for example 2,6-di-tert-butyl-4-methoxy-phenol, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octade-cyloxyphenol, 2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-bu-tyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenyl stearate, bis(3,5-di-tert-butyl-4-hy-droxyphenyl) adipate. 1.4. Tocopherols, for example a-tocopherol, p-tocopherol, y-tocopherol, 5-tocopherol and mixtures thereof (vitamin E). 1.5. Hvdroxvlated thiodiphenvl ethers, for example 2,2'-thiobis(6-tert-butyl-4-methylphenol), 2,2'-thiobis(4-octylphenol), 4,4'-thiobis(6-tert-butyl-3-methylphenol), 4,4'-thiobis(6-tert-butyl-2-methylphenol), 4,4'-thiobis(3,6-di-sec-amylphenol), 4,4'-bis(2,6-dimethyl-4-hydroxyphenyl)-disulfide. 1.6. Alkvhdenebisphenols. for example 2,2'-methylenebis(6-tert-butyl-4-methylphenol), 2,2'-methylenebis(6-tert-butyl-4-ethylphenol), 2,2'-methylenebis[4-methyl-6-(a-methylcyclohexyl)-phenol], 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,2'-methylenebis(6-nonyl-4-methylphenol), 2,2'-methylenebis(4,6-di-tert-butylphenol), 2,2'-ethyhdenebis(4,6-di-tert-butyl-phenol), 2,2'-ethylldenebis(6-tert-butyl-4-isobutylphenol), 2,2'-methylenebis[6-(a-methylben-2yl)-4-nonylphenol], 2,2'-methylenebis[6-(a,a-dimethylbenzyl)-4-nonylphenol], 4,4'-methy-lenebis(2,6-di-tert-butylphenol), 4,4'-methylenebis(6-tert-butyl-2-methylphenol), 1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol, 1,1,3-trls(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 1,1-bis(5-tert-butyl-4-hydroxy-2-methyl-phenyl)-3-n-dodecylmercaptobutane, ethylene glycol bis[3,3-bis(3'-tert- butyl-4'-hydroxyphenyl)butyrate], bis(3-tert-butyl-4-hyclroxy-5-methyl-phenyl)dicyclopenta- diene, bis[2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephtha- late, 1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane, 2,2-bis(3,5-di-tert-butyl-4-hydroxyphe- nyl)propane, 2,2-bis(5-tert-butyl-4-hydroxy2-methylphenyl)-4-n-dodecylmercaptobutane, 1,1,5,5-tetra-(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane. 1.7. 0-. N- and S-benzvl compounds, for example 3,5,3',5'-tetra-tert-butyl-4,4'-dihydroxydi-benzyl ether, octadecyl-4-hydroxy-3,5-dimethylbenzylmercaptoacetate, tridecyl-4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate, tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine, bls(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dlthloterephthalate, bis(3,5-di-tert-butyl-4-hydroxy-benzyl)sulflde, Jsooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate. 1.8. Hvdroxvbenzvlated malonates. for example dioctadecyl-2,2-bis(3,5-dl-tert-butyl-2-hy-droxybenzyOmalonate, di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)malonate, dl-dodecylmercaptoethyl-2,2-bis (3,5-di-tert-butyl-4-hydroxybenzyl)malonate, bis[4-{ 1,1,3,3-te-tramethylbutyl)phenyl]-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate. 1.9. Aromatic hvdroxvbenzv! compounds, for example 1,3,5-tris(3,5-di-tert-butyl-4-hydroxy-benzyl)-2,4,6-trJmethylbenzene, 1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetrame-thylbenzene, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol. 1.10. Triazine compounds, for example 2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxy-ani!ino)-1,3,5-triazlne, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanlhno)-1,3,5-trl-azine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine, 2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine, 1,3,5-trls(3,5-dl-tert-butyl-4-hydroxyben-zyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-trlazine, 1,3,5-tris(3,5-dl-tert-butyl-4-hydroxy-phenylproplonyl)-hexahydro-1,3,5-triazine, 1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)iso-cyanurate. 1.11. Benzvlphosphonates. for example dimethyl-2,5-di-tert-butyl-4-hydroxybenzylphospho-nate, diethyl-3,5-dl-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl3,5-di-tert-butyl-4-hy-droxybenzylphosphonate, dioctadecyl-5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate, the calcium salt of the monoethyl ester of 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid. 1.12. Acvlaminophenols, for example 4-hydroxylauranihde, 4-hydroxystearanihde, octyl N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate. 1.13. Esters of p-(3.5-di-tert-butvl-4-hvdroxvphenvl)propionic acid with mono- or polyiiydric alcohols, e.g. with methanol, ethanol, n-octanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethy-lene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis(hy-droxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylol-propane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane. 1.14. Esters of p-f5-tert-butvl-4-hvdroxv-3-methvlphenvhproplonic acid with mono- or poly-hydric alcohols, e.g. with methanol, ethanol, n-octanol, i-octanol, octadecanol, 1,6-hexanedi¬ol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis-(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethyl-olpropane, 4-hydroxymethyl-1 -phospha-2,6,7-trioxabicyclo[2.2.2]octane; 3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1 -dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]-undecane. 1.15. Esters of p-(3.5-dicvclohexvl-4-hvdroxvphenvl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, tri¬ethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxyethyl)ox-amide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hy-droxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane. 1.16. Esters of 3.5-di-tert-butvl-4-hvdroxvphenvl acetic acid with mono- or polyhydric alco¬hols, e.g. with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxyethyl)ox-amide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hy-droxymethyl-1 -phospha-2,6,7-trioxabicyclo[2.2.2]octane. 1.17. Amides of B-f3.5-di-tert-butvl-4-hvdroxvphenvnpropionic acid e.g. N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamide, N,N'-bis(3,5-di-tert-butyl-4-hydroxy-phenyipropionyl)trimethylenediamide, N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylproplonyl)hy-drazide, N,N'-bis[2-(3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyloxy)ethyl]oxamide (Nau-gard®XL-1, supphed by Uniroyal). 1.18. Ascorbic acid (vitamin C) 1.19. Aminic antioxidants, for example N,N'-di-isopropyl-p-phenylenediamine, N,N'-di-sec-bu-tyl-p-phenylenediamine, N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine, N,N'-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine, N,N'-bis(1-methylheptyl)-p-phenylenediamine, N,N'-dicy-clohexyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, N,N'-bis(2-naphthyl)-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phe-nyl-p-phenylenediamlne, N-(1-methylheptyl)-N'-phenyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, 4-(p-toluenesulfamoyl)diphenylamlne, N,N'-dimethyl-N,N'-di-sec-butyl-p-phenylenediamine, diphenylamine, N-allyldiphenylamine, 4-isopropoxydiphenyl-amine, N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine, N-phenyl-2-naph-thylamine, octylated diphenylamine, for example p,p'-di-tert-octyldiphenylamine, 4-n-butyl-aminophenol, 4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol, 4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine, 2,6-di-tert-butyl-4-dimethylamino-methylphenol, 2,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, N,N,N',N'-tetra-methyl-4,4'-diaminodiphenylmethane, 1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenyl-amino)propane, (o-tolyl)biguanide, bis[4-(1',3'-dimethylbutyl)phenyl]amine, tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- and dialkylated tert-butyl/tert-octyldiphenyl-amines, a mixture of mono- and dialkylated nonyldiphenylamines, a mixture of mono- and dialkylated dodecyldiphenylamines, a mixture of mono- and dialkylated isopropyl/isohexyl-diphenylamines, a mixture of mono- and dialkylated tert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine, phenothiazine, a mixture of mono- and dialkylated tert-butyl/tert-octylphenothiazines, a mixture of mono- and dialkylated tert-octyl-phenothiazines, N-allyiphenothiazine, N,N,N',N'-tetraphenyl-1,4-diaminobut-2-ene. 2. UV absorbers and hght stabihzers 2.1 ■ 2-(2'-Hvdroxvphenvl)benzotriazoles. for example 2-(2'-hydroxy-5'-methylphenyl)-benzo-triazole, 2-(3',5'-ch-tert-butyl-2'-hydroxyphenyl)benzotriazole, 2-(5'-tert-butyl-2'-hydroxyphe-nyl)benzotriazole, 2-(2'-hydroxy-5'-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-methyiphe-nyl)-5-chloro-benzotriazole, 2-(3'-sec-butyl-5'-tert-butyl-2'-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-4'-octyloxyphenyl)benzotriazole, 2-(3',5'-di-tert-amyl-2'-hydroxyphenyl)benzotriazole, 2-(3',5'-bis-(a,a-dinnethylbenzyl)-2'-hydroxyphenyl)benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-octyloxycarbonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3'-tert-butyl-5'-[2-(2-ethylhexyl-oxy)-carbonylethyl]-2'-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-methoxycarbonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-meth-oxycarbonylethyl)phenyl)benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-octyloxycarbonyl-ethyl)phenyl)benzotriazole, 2-(3'-tert-butyl-5'-[2-(2-ethylhexyloxy)carbonylethyl]-2'-hydroxy-phenyl)benzotriazole, 2-(3'-dodecyl-2'-hydroxy-5'-methylphenyl)benzotriazoie, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-isooctyloxycarbonylethyl)phenylbenzotriazole, 2,2'-methylene-bis[4-( 1,1,3,3-tetramethylbutyl)-6-benzotriazole-2-ylphenol]; the transesterification product of 2-[3'-tert-bu-tyl-5'-(2-methoxycarbonylethyl)-2'-hydroxyphenyl]-2H-benzotriazole with polyethylene glycol 300; [R-CHjCHg—COO-CH2CH2-3- ■ where R = 3'-tert-butyl-4'-hydroxy-5'-2H-benzotri- azol-2-ylphenyl, 2-[2'-hydroxy-3'-(a,a-dlmethylbenzyl)-5'-(1,1,3,3-tetramethylbutyl)-phenyl]-benzotriazole; 2-[2'-hydroxy-3'-(1,1,3,3-tetramethylbutyl)-5'-(a,a-dimethylbenzyl)-phenyl]ben-zotriazole. 2.2. 2-Hvdroxvbenzophenones. for example the 4-hydroxy, 4-methoxy, 4-octyloxy, 4-decyl-oxy, 4-dodecyloxy, 4-benzyloxy, 4,2',4'-trihydroxy and 2'-hydroxy-4,4'-dimethoxy derivatives. 2.3. Esters of substituted and unsubstituted benzoic acids, for example 4-tert-butyl-phenyl sahcylate, phenyl sahcylate, octylphenyl sahcylate, dibenzoyi resorcinol, bis(4-tert-butylben-zoyl)resorcinol, benzoyl resorcinol, 2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzo-ate, hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl 3,5-di-tert-butyl-4-hydroxyben-zoate, 2-methyl-4,6-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate. 2.4. Acrvlates. for example ethyl a-cyano-p,p-diphenylacrylate, isooctyl a-cyano-p,p-diphe-nylacrylate, methyl a-carbomethoxycinnamate, methyl a-cyano-p-methyl-p-methoxycinna-mate, butyl a-cyano-p-methyl-p-methoxy-cinnamate, methyl a-carbomethoxy-p-methoxycin- namate, N-(p-carbomethoxy-p-cyanovinyl)-2-methyhndohne, neopentyl tetra(a-cyano-p,p-di-phenylacrylate. 2.5. Nickel compounds, for example nickel complexes of 2,2'-thio-bls[4-(1,1,3,3-tetramethyl-butyl)phenol], such as the 1:1 or 1:2 complex, with or without additional hgands such as n-butylamine, triethanolamine or N-cyclohexyldiethanolamine, nickel dibutyldithiocarbamate, nickel salts of the monoalkyi esters, e.g. the methyl or ethyl ester, of 4-hydroxy-3,5-di-tert-butylbenzylphosphonic acid, nickel complexes of ketoximes, e.g. of 2-hydroxy-4-methylphe-nylundecylketoxime, nickel complexes of 1-phenyl-4-lauroyl-5-hydroxypyrazole, with or with¬out additional hgands. 2.6. Stericallv hindered amines, for example bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)succinate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1 -octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperi-dyl) n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensate of 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, hnear or cychc condensates of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-tert-octylamino-2,6-di-chloro-1,3,5-triazine, tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate, tetrakis(2,2,6,6-tetra-methyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, 1,1'-(1,2-ethanediyl)-bis(3,3,5,5-tetrame-thylpiperazinone), 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethyl-piperidine, bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)-malonate, 3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, bis(1-octyl-oxy-2,2,6,6-tetramethylplperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)succi-nate, hnear or cychc condensates of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylene-diamine and 4-morphohno-2,6-dichloro-1,3,5-triazlne, the condensate of 2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)-ethane, the condensate of 2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)ethane, 8-acetyl-3-dodecyl-7,7,9,9-tetrame-thyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, 3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyr-rohdine-2,5-dione, 3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperldyl)pyrrohdine-2,5-dione, a mixture of 4-hexadecyloxy- and 4-stearyloxy-2,2,6,6-tetramethylpiperidine, a condensate of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, a condensate of 1,2-bis(3-aminopropylamino)ethane and 2,4,6-trlchloro-1,3,5-triazine as well as 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No. [136504-96-6]); a condensate of 1,6-hexanediamine and 2,4,6-trichloro-1,3,5-triazine as well as N,N-dibutylamlne and 4-butylamino-2,2,6,6-tetramethylplperidine (CAS Reg. No. [192268- 64-7]); N-(2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsucclnimide, N-(1,2,2,6,6-pentamethyl-4- piperldyl)-n-dodecylsuccinimide, 2-undecyl-7,7,9,9-tetramethyl-1 -oxa-3,8-diaza-4-oxo-splro- [4,5]decane, a reaction product of 7,7,9,9-tetranriethyl-2-cycloundecyl-1-oxa-3,8-dlaza-4-oxo- spiro-[4,5]decane and epichlorohydrin, 1,1-bis(1,2,2,6,6-pentamethyl-4-plperidyloxycarbo- nyl)-2-(4-methoxyphenyl)ethene, N,N'-bis-formyl-N,N'-bis(2,2,6,6-tetramethyl-4-piperldyl)- hexamethylenediamlne, a diester of 4-methoxymethylenemalonlc acid with 1,2,2,6,6- pentamethyl-4-hydroxypiperldlne, poly[methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4-plperi- dyl)]siloxane, a reaction product of maleic add anhydrlde-a-olefin copolymer with 2,2,6,6- tetramethyl-4-aminopiperldlne or 1,2,2,6,6-pentamethyl-4-amlnopiperidine, 2,4-bls[N-(1- cyclohexyloxy-2,2,6,6-tetramethylplperidine-4-yl)-N-butylamino]-6-(2-hydroxyethyl)amlno- 1,3,5-triazine, 1 -(2-hydroxy-2-methylpropoxy)-4-octadecanoyloxy-2,2,6,6-tetramethylpiperl- dlne, 5-(2-ethylhexanoyl)oxymethyl-3,3,5-trimethyl-2-nnorphollnone, Sanduvor (Clarlant; CAS Reg. No. 106917-31-1], 5-(2-ethylhexanoyl)oxymethyl-3,3,5-trlmethyl-2-morphohnone, the reaction product of 2,4-bis[(1-cyclohexyloxy-2,2,6,6-plperidlne-4-yl)butylamino]-6-chloro-s- triazlne with N,N'-bls(3-aminopropyl)ethylenedlamine), 1,3,5-trls(N-cyclohexyl-N-(2,2,6,6- tetramethylplperazlne-3-one-4-yl)amino)-s-triazine, 1,3,5-trls(N-cyclohexyl-N-(1,2,2,6,6- pentamethylplperazlne-3-one-4-yl)amlno)-s-triazlne. 2.7. Oxamides. for example 4,4'-dioctyloxyoxanihde, 2,2'-diethoxyoxanihde, 2,2'-dioctyloxy-5,5'-dl-tert-butoxanillde, 2,2'-dldodecyloxy-5,5'-di-tert-butoxanihde, 2-ethoxy-2'-ethyloxanlllde, N,N'-bls(3-dimethylaminopropyl)oxamide, 2-ethoxy-5-tert-butyl-2'-ethoxanihde and its mixture with 2-ethoxy-2'-ethyl-5,4'-di-tert-butoxaniiide, mixtures of o- and p-methoxy-disubstituted oxanihdes and mixtures of o- and p-ethoxy-disubstltuted oxanllldes. 2.8. 2-(2-Hvdroxvphenvn-1.3.5-triazines. for example 2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-octyloxyphenyI)-4,6-bls(2,4-dimethylphenyl)-1,3,5-triazlne, 2-(2,4-dlhydroxyphenyl)-4,6-bis(2,4-dlmethylphenyl)-1,3,5-trlazine, 2,4-bls(2-hydroxy-4-propyl-oxyphenyl)-6-(2,4-dlmethyiphenyl)-1,3,5-triazlne, 2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bls(2,4-dlmethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dlmethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropoxy)phenyl]-4,6-bis(2,4-dlmethyl)-1,3,5-trlazine, 2-[2-hydroxy-4-(2-hydroxy-3-octyloxypropyloxy)phenyl]-4,6-bls(2,4-dimethy!)-1,3,5-trlazlne, 2-[4- (clodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)- 1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxypropoxy)phenyl]-4,6-bis(2,4-dimethyl- phenyl)-1,3,5-tria2ine, 2-(2-hydroxy-4-hexyloxy)phenyl-4,6-diphenyl-1,3,5-triazine, 2-(2-hydr- oxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2,4,6-tris[2-hydroxy-4-(3-butoxy-2- hydroxypropoxy)phenyl]-1,3,5-triazine, 2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine, 2-{2-hydroxy-4-[3-(2-ethyihexyl-1-oxy)-2-hydroxypropyloxy]phenyl}-4,6-bis(2,4-dimethyiphenyl)-1,3,5-triazine, 2,4-bis(4-[2-ethylhexyloxy]-2-hydroxyphenyi)-6-(4-methoxy-p[ienyl)-1,3,5-triazine. 3. IVIetal deactivators, for example N,N'-diphenyloxamide, N-sahcylal-N'-sahcyloyI hydrazine, N,N'-bis(sahcyloyl)hiydrazine, N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine, 3-sahcyloylamino-1,2,4-triazole, bis(benzyhdene)oxalyl dihydrazide, oxanihde, isophttialoyl dihydrazide, sebacoyi bisphenylhydrazide, N,N'-diacetyladipoyl ditiydrazide, N,N'-bis(sahcyl-oyl)oxalyl dihydrazide, N,N'-bis(sahcyloyl)thiopropionyl ditiydrazlde. 4. Phosphites and phosphonites. for example triphenyl phosphite, diphenylall The following phosphites are especially preferred: Tris(2,4-di-tert-butylpheny!) phosphite (lrgafos®168, Ciba Specialty Chemicals Inc.), tris(no-nylphenyl) phosphite. 5. Hvdroxvlamines. for example N,N-dibenzylhydroxylamine, N,N-diethylhydroxylamine, N,N- dioctylhydroxylamine, N,N-dilaurylhydroxylamine, N,N-ditetradecylhydroxylamine, N,N- dihexadecylhydroxylamine, N,N-dioctadecylhydroxylamine, N-hexadecyl-N-octadecylhydrox- ylamine, N-heptadecyl-N-octadecylhydroxylamine, N,N-dialkylhydroxylamine derived from hydrogenated tallow amine. 6. Nitrones, for example, N-benzyl-alptia-pfienylnitrone, N-etiiyl-alpha-methylnitrone, N-octyl- alpha-heptylnitrone, N-lauryl-alpha-undecylnitrone, N-tetradecyl-alpha-tridecylnnitrone, N- hexadecyl-alpha-pentadecylnitrone, N-octadecyl-alpha-heptadecyinitrone, N-hexadecyl-al- piia-heptadecylnitrone, N-ocatadecyl-alpha-pentadecylnitrone, N-iieptadecyl-alpha-hepta- decylnitrone, N-octadecyl-alpha-hexadecylnitrone, nitrone derived from N,N-dialkylhydroxyl- amine derived from hydrogenated tallow amine. 7. Thiosvneroists. for example dilauryl thiodipropionate, dimistryl thiodipropionate, distearyl thiodipropionate or distearyl disulfide. 8. Peroxide scavengers, for example esters of p-thiodipropionic acid, for example the lauryl, stearyl, myristyl or tridecyl esters, mercaptobenzimidazole or the zinc salt of 2-mercapto-benzimidazole, zinc dibutyldithiocarbamate, dioctadecyl disulfide, pentaerythritol tetrakis(p-dodecylmercapto)propionate. 9. Polvamide stabihzers, for example copper salts in combination with iodides and/or phos¬ phorus compounds and salts of divalent manganese. 10. Basic co-stabihzers, for example melamine, polyvinylpyrrohdone, dicyandiamide, triallyl cyanurate, urea derivatives, hydrazine derivatives, amines, polyamides, polyurethanes, alkah metal salts and alkahne earth metal salts of higher fatty acids, for example calcium stearate, zinc stearate, magnesium behenate, magnesium stearate, sodium ricinoleate and potassium palmitate, antimony pyrocatecholate or zinc pyrocatecholate. 11 ■ Nucleating agents, for example inorganic substances, such as talcum, metal oxides, such as titanium dioxide or magnesium oxide, phosphates, carbonates or sulfates of, preferably, alkahne earth metals; organic compounds, such as mono- or polycarboxyhc acids and the salts thereof, e.g. 4-tert-butylbenzoic acid, adipic acid, diphenylacetic acid, sodium succinate or sodium benzoate; polymeric compounds, such as ionic copolymers (ionomers). Especially preferred are 1,3:2,4-bis(3',4'-dimethylbenzyhdene)sorbitol, 1,3:2,4-di(paramethyl-dibenzyhdene)sorbitol, and 1,3:2,4-di(benzyhdene)sorbitol. 12. Fillers and reinforcing agents, for example calcium carbonate, sihcates, glass fibres, glass beads, asbestos, talc, kaohn, mica, barium sulfate, metal oxides and hydroxides, car¬bon black, graphite, wood flour and flours or fibers of other natural products, synthetic fibers. 13. Other additives, for example plasticisers, lubricants, emulsifiers, pigments, rheology additives, catalysts, flow-control agents, optical brighteners, flameproofing agents, antistatic agents and blowing agents. 14. Benzofuranones and indohnones. for example those disclosed in U.S. 4,325,863; U.S. 4,338,244; U.S. 5,175,312; U.S. 5,216,052; U.S. 5,252,643; DE-A-4316611; DE-A-4316622; DE-A-4316876; EP-A-0589839, EP-A-0591102; EP-A-1291384 or 3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-tert-butylbenzofuran-2-one, 5,7-di-tert-butyl-3-[4-(2-stearoyloxy-ethoxy)phenyl]benzofuran-2-one, 3,3'-bis[5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)ben-zofuran-2-one], 5,7-di-tert-butyl-3-(4-ethoxyphenyl)benzofuran-2-one, 3-(4-acetoxy-3,5-di-methylphenyl)-5,7-di-tert-butyibenzofuran-2-one, 3-(3,5-dimethyl-4-pivaloyloxyphenyI)-5,7-di-tert-butylbenzofuran-2-one, 3-(3,4-dimethylphenyl)-5,7-di-tert-butylbenzofuran-2-one, 3-(2,3-dimethylphenyl)-5,7-di-tert-butylbenzofuran-2-one, 3-(2-acetyl-5-isooctylphenyl)-5-isooctyl-benzofuran-2-one. The above additives are in general apphed in an amount between 0.01 and 2% by weight based on the weight of the thermoplastic polymer. A further aspect of the invention is a method for enlarging the optimal peak temperature range in rotational molding processes of thermoplastic polymers by the use of a secondary sterically hindered amine compound as processing additive. Accordingly disclosed is a method for enlarging the processing window towards higher peak internal air temperatures in rotational molding processes of thermoplastic polymers, which method comprises incorporating a secondary sterically hindered amine into a thermoplastic polymer and subjecting the polymer to a rotational molding process.. Yet another embodiment of the invention is a process for the production of thermoplastic hollow articles, which process comprises mixing a thermoplastic polymer with a secondary sterically hindered amine and subjecting this mixture to a rotational molding process where the peak internal temperature range is from about 215 to about 250C, wherein when the thermoplastic polymer is polyethylene, the hindered amine is not a hnear or cychc condensate of N,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)- hexamethylenediamine and 4-morphohno-2,6-dichloro-1,3,5-triazine. Definitions and preferences given above apply also for the other aspect of the invention. The following examples illustrate the invention. Example 1: Preparation of Polyolefin Hollow Articles by a rotational molding process 100 parts medium density polyethylene, copolymerized with hexene (nominal melt index 3.3 g/10 min., density 0.938 g/cm^) are dry blended with 0.050 parts of zinc stearate and a combination of additional stabihzers as given in Table 1. The mixtures are melt compounded into pellets at 190 °C in a Superior/MPM extruder using a 24:1 L/D screw with Maddock mixing head at 100 rpm. The compounded pellets are ground to a uniform particle size (150-500 \|hm) prior to the rotational molding process. This grinding step increases the surface area of the particles leading to faster heat absorption, and thus reducing overall energy consumption. The rotational molding process is performed in laboratory scale equipment FSP M20 "Clamshell". The ground resin is placed in an aluminum mold, which is rotated biaxially in a gas fired oven. Hot air is circulated by blowers in the chamber while the temperature is increased to 274°C. This temperature is maintained for a specific time, which will give a certain peak internal air temperature (PIAT) as given in Table 2. Subsequently, the oven is opened and while still rotating, the mold is cooled with forced air circulation for 7.3 minutes, followed by water spray mist for 1.5 minutes, air coohng for 2 minutes, water spray 2.9 minutes and air coohng 4.4 minutes. Throughout the entire heating and coohng cycles, i the speed of the major axis is maintained at 6 rpm with a 4 : 1 ratio of rotation. After the coohng cycles, the mold is opened and the hollow object removed. The processing range is defined as peak internal air temperature range (PIAT) in which a part with high impact strength can be produced. The impact strength is measured with the Dynatup Falhng weight method (25lb/20"") according to ASTM D-3763 at -40° C. The data clearly indicate that the useful process range can be significantly shifted towards higher temperatures by the use of secondary sterically hindered amine compounds without sacrificing the impact strength. Example 2: Preparation of Polyolefin Hollow Articles by a rotational molding process The procedure given in example 1 has been repeated with further additives as outhned in Table 3. The results are presented in Table 4 Whereas the processing temperature, as measured by the peak internal air temperature, (PIAT) should not exceed 198° C if no sterically hindered amine is present, 210° are acceptable when a tertiary sterically hindered amine is present. However, this temperature can further be extended up to 221° C, when, according to the invention, a secondary sterically hindered amine has been added. ®Irganox 3114 is a phenohc antioxidant from Ciba Specialty Chemicals, ®Irgastab FS042 is N,N-di(tallow alkyl)hydroxylamine from Ciba Specialty Chemicals, ®Irgafos 168 is a trisaryl phosphite from Ciba Specialty Chemicals, ®Tinuvin 622 is a tertiary sterically hindered amine from Ciba Specialty Chemicals, ®Cyasorb UV 3346 is a secondary sterically hindered amine from Cytech Industries, ®Chimassorb 944 is a secondary sterically hindered amine from Ciba Specialty Chemicals, ®Chimassorb 2020 is a secondary sterically hindered amine from Ciba Specialty Chemicals, ®Chimassorb 119 is a tertiary sterically hindered amine from Ciba Specialty Chemicals, ®Hostavin N 30 is a tertiary sterically hindered amine from Clariant, ®Tinuvin 770 is a secondary sterically hindered amine from Ciba Specialty Chemicals, ®Tinuvin 783 is a mixture of a secondary and tertiary sterically hindered amine from Ciba Specialty Chemicals. Claims 1. Use of a secondary sterically hindered amine compound as processing additive for enlarging the processing window towards higher peak internal air temperatures in rotational molding processes of thermoplastic polymers. 2. Use according to claim 1 wherein the sterically hindered amine is a compound containing at least one group of the formula (I) or (II) in which * indicates a bond G is hydrogen or methyl, and G1 and G2, independently of one another, are hydrogen, methyl or together are a substituent =0. 3. Use according to claim 2 wherein the sterically hindered amine is a compound containing at least one group of formula (la). 4. Use according to claim 1 wherein the sterically hindered amine compound is added in an amount from 0.01 to 5% by weight, based on the weight of the thermoplastic polymer. 5. Use according to claim 1 wherein the thermoplastic polymer is a polyolefin, polyvinylchloride or polyamide. 6. Use according to claim 1 wherein the thermoplastic polymer is polyethylene. 7. Use according to claim 1 wherein the peak internal air temperature range in rotational molding processes is enlarged up to 10 to 50° C towards higher temperatures. 8. Use according to claim 1 wherein the peak internal air temperature range is from 215 to 250° C 9. Use according to claim 1 wherein in the rotational molding process an additional stabilizer selected from the group consisting of a UV-absorber, a sterically hindered amine, different from that of formula (I) or (II), a phenolic antioxidant, a phosphite or phosphonite and a benzofuranone or indolinone is present. 10. A method for enlarging the processing window towards higher peak internal air temperatures In rotational molding processes of thermoplastic polymers, which method comprises incorporating a secondary sterically hindered amine into a thermoplastic polymer and subjecting the polymer to a rotational molding process. 11. A method of using a secondary sterically hindered amine compound as processing additive for enlarging the processing window towards higher peak internal air temperatures in rotational molding processes of thermoplastic polymers.

Full Text

Use of Secondary Stericallv Hindered Amines as Processing Additives in Rotomoldina Processes
The instant invention pertains to the use of secondary sterically hindered amines as processing additives in rotational molding processes. These additives increase process ^ stabihty, since they provide a broader temperature range towards higher temperatures during the melt processing step.
Rotational molding is a highly versatile manufacturing option that allows for unhmited design possibihties with the added benefit of low production costs.
The rotational molding process (rotomolding process) starts with a good quahty mold that is placed in a molding machine that has a loading, heating, and coohng area.
Several molds may be placed on the machine at the same time. Pre-measured plastic resin is loaded into each mold, and then the molds are moved into the oven where they are slowly rotated on both the vertical and horizontal axis. The melting resin sticks to the hot mold and coats every surface evenly. The mold continues to rotate during the coohng cycle so the parts retain an even wall thickness.
Once the parts are cooled, they are released from the mold. The rotational speed, heating and coohng times may be all controlled throughout the process.
Rotational molding offers design advantages over other molding processes. With proper design, parts that are assembled from several pieces can be molded as one part, ehminating expensive fabrication costs.
The process also has a number of inherent design strengths, such as consistent wall thickness and strong outside corners that are virtually stress free. If additional strength is required, reinforcing ribs can be designed into the part.
Rotational molding dehvers the product the designer envisions. Designers can select the best material for their apphcation, including materials that meet FDA requirements. Additives to help make the part weather resistant, flame retardant, or static free can be specified.

And because parts are formed with heat and rotation, rather than pressure, molds don't need to be engineered to withstand the high pressure of injection molding.
Production costs for product conversions are reduced because hghtweight plastics replace heavier, often more costly materials, which makes rotational molding as cost effective for one-of-a-kind prototypes as it is for large production runs
Rotational molding is versatile and able to handle a vast variety of shapes and sizes. Many parts cannot be readily produced by any other method. Typical examples are specialty tanks and containers for fuel, water, and chemical processing, hvestock feeders, drainage systems, food service containers, instrument housings, vending machines, highway barriers and road markers. Other apphcation areas are consumer products, toys and transportation. Many aspects of the rotational molding process are, for example, described by R. J. Crawford and J. L. Throne in Rotational Molding Technology, Plastics Design hbrary, Wilham Andrew Pubhshing, 2001.
As mentioned above rotational speed, heating and coohng times may be all controlled throughout the process. The maximum temperature of the air, which is reached inside the hollow molded article, depends strongly on the heating time. This temperature is also called peak internal air temperature (PIAT). It correlates with the temperature of the molten resin.
The concept of peak internal air temperature (PIAT) and the consequences, if a too low or too high PIAT is apphed, is for example described by M. C. Cramez et al. in Proc. Instn Mech. Engrs. Vol. 217 Part B: J. of Engineering Manufacture, 2003.
The peak internal air temperature can influence the final properties of the molded product. For example, if the temperature becomes too high, a strong yellowing may occur and also the mechanical properties are negatively affected, for example, the impact strength decreases significantly. If the temperature remains too low the final properties can also be adversely affected because the resins have not been properly molten. In other words, there is only a small temperature range for achieving the desired final properties. It is therefore of high interest to widen this temperature range or processing window, within which almost constant mechanical properties are obtained.

Botkin et al in "An additive approach to cycle time reduction in rotational molding" Rotational Molding by Design Conference, Society of Plastics Engineers, 2004 have demonstrated that by using a proprietary process stabihzer, the PIAT can be shifted towards lower temperatures maintaining good impact strength. This con-esponds to broadening the processing window towards lower temperatures.
Surprisingly it has now been found that when a secondary hindered amine compound is added to the resin formulation a significantly broader processing window towards higher temperatures is achieved without adversely affecting color and mechanical properties of the molded article.
Consequently one aspect of the invention is the use of a secondary stericahy hindered amine compound as processing additive for enlarging the processing window towards higher peak internal air temperatures in rotational molding processes of thermoplastic polymers.
Under processing window there Is understood the temperature range, as measured by the peak internal air method (PIAT), within which the mechanical properties and/or the color of the molded article remain essentially the same. A particularly suitable mechanical property to measure is impact strength, for example at low temperatures. Low temperature means in this context from 0° to -50° C, particularly -20° C to -40° C.

Preferred are the following commercial compounds.
Chimassorb 2020®, Chlmassorb 944®, Tinuvin 770® and Tinuvin 783®, Cyasorb UV 3346®, Cyasorb UV 3581®, Dastib 845®, Dastib 1082®, Diacetam 5, Fero 806-X®, Goodrlte 3034®, Goodrite 3150®, HALS IC-TAM, Hostavin N 20®, Hostavin N 24®, Hostavin N 30®, Huls S-95®, ICI PA 500®, hchtschutzstoff UV 31, Luchem HA-B 18®, Mark LA 55®, Mark LA 57®, Mark LA 67®, Mark LA 68®, Sanduvor 3050®, Sumillzer 61®, Sumillzer 70®, Suimisorb TM 61®, UVASORB HA 88®, Uvinul 4049®, Uvlnul 5050®, Uvasll 299®, Uvasil 125®.
These compounds are commercially available and described In: US-A-5,679,733, US-A-3,640,928, US-A-5,204,473, US-A-4,619,958, US-A-4,110,306, US-A-4,110,334, US-A-4,689,416, US-A-4,408,051, SU-A-768,175 (Denwent 88-138,751/20), US-A-5,049,604, US-

A-4,769,457, US-A-4,356,307, US-A-4,619,956, US-A-5,182,390, GB-A-2,269,819, US-A-4,292,240, US-A-5,026,849, US-A-5,071,981, US-A-4,547,538, US-A-4,976,889, US-A-4,086,204, US-A-6,046,304, US-A-4,331,586, US-A-4,108,829, US-A-5,051,458, WO-A-94/12,544 (Derwent 94-177,274/22), DD-A-262,439 (Derwent 89-122,983/17), US-A-4,857,595, US-A-4,529,760, US-A-4,477,615 (CAS 136,504-96-6), US-A-4,340,534, WO-A-98/51,690, EP-A-1,803, the disclosures of which are incorporated by reference,
The sterically hindered amine compound according to the invention is preferably added in an amount from 0.01 to 5%, more preferably from 0.05 to 2% and most preferably from 0.1 to 1 % by weight, based on the weight of the thermoplastic polymer.
For instance the thermoplastic polymer is a polyolefin, a polyvinylchloride or a polyamide. Examples are given below.
1. Polymers of monoolefins and diolefins, for example polypropylene, polyisobutylene, po-lybut-1-ene, poly-4-methylpent-1-ene, polyvinylcyclohexane, polyisoprene or polybutadiene, as well as polymers of cycloolefins, for instance of cyclopentene or norbornene, polyethylene (which optionally can be crosshnked), for example high density polyethylene (HOPE), high density and high molecular weight polyethylene (HDPE-HMW), high density and ultrahigh molecular weight polyethylene (HDPE-UHMW), medium density polyethylene (MDPE), low density polyethylene (LDPE), hnear low density polyethylene (LLDPE), (VLDPE) and (ULDPE).
Polyolefins, i.e. the polymers of monoolefins exemphfied in the preceding paragraph, prefe¬rably polyethylene and polypropylene, can be prepared by different, and especially by the following, methods:
a) radical polymerisation (normally under high pressure and at elevated temperature).
b) catalytic polymerisation using a catalyst that normally contains one or more than one
metal of groups IVb, Vb, VIb or VIII of the Periodic Table. These metals usually have
one or more than one hgand, typically oxides, hahdes, alcoholates, esters, ethers,
amines, alkyls, alkenyls and/or aryls that may be either n- or a-coordinated. These
metal complexes may be in the free form or fixed on substrates, typically on
activated magnesium chloride, titanium(lll) chloride, alumina or sihcon oxide. These

catalysts may be soluble or insoluble in the polymerisation medium. The catalysts can be used by themselves in the polymerisation or further activators may be used, typically metal alkyls, metal hydrides, metal alkyl hahdes, metal alkyl oxides or metal alkyloxanes, said metals being elements of groups la, lla and/or Iha of the Periodic Table. The activators may be modified conveniently with further ester, ether, amine or silyl ether groups. These catalyst systems are usually termed Philhps, Standard Oil Indiana, Ziegler (-Natta), TNZ (DuPont), metallocene or single site catalysts (SSC).
2. Mixtures of the polymers mentioned under 1), for example mixtures of polypropylene with polyisobutylene, polypropylene with polyethylene (for example PP/HDPE, PP/LDPE) and mixtures of different types of polyethylene (for example LDPE/HDPE).
3. Copolymers of monoolefins and diolefins with each other or with other vinyl monomers, for example ethylene/propylene copolymers, hnear low density polyethylene (LLDPE) and mixtures thereof with low density polyethylene (LDPE), propylene/but-1-ene copolymers, propylene/isobutylene copolymers, ethylene/but-1-ene copolymers, ethylene/hexene copo¬lymers, ethylene/methylpentene copolymers, ethylene/heptene copolymers, ethylene/octene copolymers, ethylene/vinylcyclohexane copolymers, ethylene/cycloolefin copolymers (e.g. ethylene/norbornene hke COC), ethylene/1-olefins copolymers, where the 1-olefin is gene¬rated in-situ; propylene/butadiene copolymers, isobutylene/isoprene copolymers, ethylene/vi-nylcyclohexene copolymers, ethylene/alkyi acrylate copolymers, ethylene/alkyi methacrylate copolymers, ethylene/vinyl acetate copolymers or ethylene/acryhc acid copolymers and their salts (ionomers) as well as terpolymers of ethylene with propylene and a diene such as hexadiene, dicyclopentadiene or ethyhdene-norbornene; and mixtures of such copolymers with one another and with polymers mentioned in 1) above, for example polypropylene/ethy-lene-propylene copolymers, LDPE/ethylene-vinyl acetate copolymers (EVA), LDPE/ethylene-acryhc acid copolymers (EAA), LLDPE/EVA, LLDPE/EAA and alternating or random polyal-kylene/carbon monoxide copolymers and mixtures thereof with other polymers, for example polyamides.
4. Polyamides and copolyamides derived from diamines and dicarboxyhc acids and/or from aminocarboxyhc acids or the corresponding lactams, for example polyamide 4, polyamide 6, polyamide 6/6, 6/10, 6/9, 6/12, 4/6, 12/12, polyamide 11, polyamide 12, aromatic polyamides

starting from m-xylene diamine and adipic acid; polyamides prepared from hexamethylenediamine and isophthahc or/and terephtlnahc acid and with or without an ela¬stomer as modifier, for example poly-2,4,4,-trimethylhexamethylene terephthalamide or poly-m-phenylene isophthalamide; and also block copolymers of the aforementioned polyamides with poiyolefins, olefin copolymers, ionomers or chemically bonded or grafted elastomers; or with polyethers, e.g. with polyethylene glycol, polypropylene glycol or polytetramethylene glycol; as well as polyamides or copolyamides modified with EPDI\/I or ABS; and polyamides condensed during processing (Rll\/I polyamide systems).
Particular preference is given to polyethylene preferably hnear low density polyethylene (LLDPE).
For example the peak internal air temperature range in rotational molding processes is enlarged up to 10 to 50° C, preferably up to 15 to 40° C towards higher temperatures. The reference being without the addition of a sterically hindered amine.
Preferably the peak internal air temperature range is from 210 to 250° C, more preferably from 215 to 250° C and most preferably from 220 to 250° C.
The above temperature range corresponds to the preferred processing window, within which the mechanical properties and/or the color of the article are not adversely affected.
In a specific embodiment of the invention an additional stabihzer selected from the group consisting of a UV-absorber, a sterically hindered amine, different from that of formula (I) or (II), a phenohc antioxidant, a phosphite or phosphonite and a benzofuranone or indohnone is present.
Examples for the above mentioned additives are given below.
1. Antioxidants
1.1. Alkviated monophenols. for example 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-di-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-bu-tyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, 2-(a-methylcyclohexyl)-4,6-dimethyl-

phenol, 2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-di-tert-butyl-4-meth-oxymethylphenol, nonylphenols which are hnear or branched in the side chains, for example, 2,6-di-nonyl-4-methylphenol, 2,4-dimethyl-6-(1'-methylundec-1'-yl)phenol, 2,4-dimethyl-6-(1'-methylheptadec-1'-yl)phenol, 2,4-dimethyl-6-(r-methyltridec-r-yl)phenol and mixtures there¬of.
1.2. AlkvlthiomethvlDhenols. for example 2,4-dioctylthiomethyl-6-tert-butylpheno!, 2,4-dloctyl-thiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-ethylphenol, 2,6-di-dodecylthiomethyl-4-nonylphenol.
1.3. Hvdroquinones and alkylated hvdroquinones. for example 2,6-di-tert-butyl-4-methoxy-phenol, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octade-cyloxyphenol, 2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-bu-tyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenyl stearate, bis(3,5-di-tert-butyl-4-hy-droxyphenyl) adipate.
1.4. Tocopherols, for example a-tocopherol, p-tocopherol, y-tocopherol, 5-tocopherol and mixtures thereof (vitamin E).
1.5. Hvdroxvlated thiodiphenvl ethers, for example 2,2'-thiobis(6-tert-butyl-4-methylphenol), 2,2'-thiobis(4-octylphenol), 4,4'-thiobis(6-tert-butyl-3-methylphenol), 4,4'-thiobis(6-tert-butyl-2-methylphenol), 4,4'-thiobis(3,6-di-sec-amylphenol), 4,4'-bis(2,6-dimethyl-4-hydroxyphenyl)-disulfide.
1.6. Alkvhdenebisphenols. for example 2,2'-methylenebis(6-tert-butyl-4-methylphenol), 2,2'-methylenebis(6-tert-butyl-4-ethylphenol), 2,2'-methylenebis[4-methyl-6-(a-methylcyclohexyl)-phenol], 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,2'-methylenebis(6-nonyl-4-methylphenol), 2,2'-methylenebis(4,6-di-tert-butylphenol), 2,2'-ethyhdenebis(4,6-di-tert-butyl-phenol), 2,2'-ethylldenebis(6-tert-butyl-4-isobutylphenol), 2,2'-methylenebis[6-(a-methylben-2yl)-4-nonylphenol], 2,2'-methylenebis[6-(a,a-dimethylbenzyl)-4-nonylphenol], 4,4'-methy-lenebis(2,6-di-tert-butylphenol), 4,4'-methylenebis(6-tert-butyl-2-methylphenol), 1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol, 1,1,3-trls(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 1,1-bis(5-tert-butyl-4-hydroxy-2-methyl-phenyl)-3-n-dodecylmercaptobutane, ethylene glycol bis[3,3-bis(3'-tert-

butyl-4'-hydroxyphenyl)butyrate], bis(3-tert-butyl-4-hyclroxy-5-methyl-phenyl)dicyclopenta-
diene, bis[2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephtha-
late, 1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane, 2,2-bis(3,5-di-tert-butyl-4-hydroxyphe-
nyl)propane, 2,2-bis(5-tert-butyl-4-hydroxy2-methylphenyl)-4-n-dodecylmercaptobutane,
1,1,5,5-tetra-(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane.
1.7. 0-. N- and S-benzvl compounds, for example 3,5,3',5'-tetra-tert-butyl-4,4'-dihydroxydi-benzyl ether, octadecyl-4-hydroxy-3,5-dimethylbenzylmercaptoacetate, tridecyl-4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate, tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine, bls(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dlthloterephthalate, bis(3,5-di-tert-butyl-4-hydroxy-benzyl)sulflde, Jsooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate.
1.8. Hvdroxvbenzvlated malonates. for example dioctadecyl-2,2-bis(3,5-dl-tert-butyl-2-hy-droxybenzyOmalonate, di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)malonate, dl-dodecylmercaptoethyl-2,2-bis (3,5-di-tert-butyl-4-hydroxybenzyl)malonate, bis[4-{ 1,1,3,3-te-tramethylbutyl)phenyl]-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate.
1.9. Aromatic hvdroxvbenzv! compounds, for example 1,3,5-tris(3,5-di-tert-butyl-4-hydroxy-benzyl)-2,4,6-trJmethylbenzene, 1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetrame-thylbenzene, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol.

1.10. Triazine compounds, for example 2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxy-ani!ino)-1,3,5-triazlne, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanlhno)-1,3,5-trl-azine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine, 2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine, 1,3,5-trls(3,5-dl-tert-butyl-4-hydroxyben-zyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-trlazine, 1,3,5-tris(3,5-dl-tert-butyl-4-hydroxy-phenylproplonyl)-hexahydro-1,3,5-triazine, 1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)iso-cyanurate.
1.11. Benzvlphosphonates. for example dimethyl-2,5-di-tert-butyl-4-hydroxybenzylphospho-nate, diethyl-3,5-dl-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl3,5-di-tert-butyl-4-hy-droxybenzylphosphonate, dioctadecyl-5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate, the calcium salt of the monoethyl ester of 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid.

1.12. Acvlaminophenols, for example 4-hydroxylauranihde, 4-hydroxystearanihde, octyl N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.
1.13. Esters of p-(3.5-di-tert-butvl-4-hvdroxvphenvl)propionic acid with mono- or polyiiydric alcohols, e.g. with methanol, ethanol, n-octanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethy-lene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis(hy-droxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylol-propane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.
1.14. Esters of p-f5-tert-butvl-4-hvdroxv-3-methvlphenvhproplonic acid with mono- or poly-hydric alcohols, e.g. with methanol, ethanol, n-octanol, i-octanol, octadecanol, 1,6-hexanedi¬ol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis-(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethyl-olpropane, 4-hydroxymethyl-1 -phospha-2,6,7-trioxabicyclo[2.2.2]octane; 3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1 -dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]-undecane.
1.15. Esters of p-(3.5-dicvclohexvl-4-hvdroxvphenvl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, tri¬ethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxyethyl)ox-amide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hy-droxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.
1.16. Esters of 3.5-di-tert-butvl-4-hvdroxvphenvl acetic acid with mono- or polyhydric alco¬hols, e.g. with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxyethyl)ox-amide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hy-droxymethyl-1 -phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.17. Amides of B-f3.5-di-tert-butvl-4-hvdroxvphenvnpropionic acid e.g. N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamide, N,N'-bis(3,5-di-tert-butyl-4-hydroxy-phenyipropionyl)trimethylenediamide, N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylproplonyl)hy-drazide, N,N'-bis[2-(3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyloxy)ethyl]oxamide (Nau-gard®XL-1, supphed by Uniroyal).
1.18. Ascorbic acid (vitamin C)
1.19. Aminic antioxidants, for example N,N'-di-isopropyl-p-phenylenediamine, N,N'-di-sec-bu-tyl-p-phenylenediamine, N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine, N,N'-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine, N,N'-bis(1-methylheptyl)-p-phenylenediamine, N,N'-dicy-clohexyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, N,N'-bis(2-naphthyl)-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phe-nyl-p-phenylenediamlne, N-(1-methylheptyl)-N'-phenyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, 4-(p-toluenesulfamoyl)diphenylamlne, N,N'-dimethyl-N,N'-di-sec-butyl-p-phenylenediamine, diphenylamine, N-allyldiphenylamine, 4-isopropoxydiphenyl-amine, N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine, N-phenyl-2-naph-thylamine, octylated diphenylamine, for example p,p'-di-tert-octyldiphenylamine, 4-n-butyl-aminophenol, 4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol, 4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine, 2,6-di-tert-butyl-4-dimethylamino-methylphenol, 2,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, N,N,N',N'-tetra-methyl-4,4'-diaminodiphenylmethane, 1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenyl-amino)propane, (o-tolyl)biguanide, bis[4-(1',3'-dimethylbutyl)phenyl]amine, tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- and dialkylated tert-butyl/tert-octyldiphenyl-amines, a mixture of mono- and dialkylated nonyldiphenylamines, a mixture of mono- and dialkylated dodecyldiphenylamines, a mixture of mono- and dialkylated isopropyl/isohexyl-diphenylamines, a mixture of mono- and dialkylated tert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine, phenothiazine, a mixture of mono- and dialkylated tert-butyl/tert-octylphenothiazines, a mixture of mono- and dialkylated tert-octyl-phenothiazines, N-allyiphenothiazine, N,N,N',N'-tetraphenyl-1,4-diaminobut-2-ene.
2. UV absorbers and hght stabihzers

2.1 ■ 2-(2'-Hvdroxvphenvl)benzotriazoles. for example 2-(2'-hydroxy-5'-methylphenyl)-benzo-triazole, 2-(3',5'-ch-tert-butyl-2'-hydroxyphenyl)benzotriazole, 2-(5'-tert-butyl-2'-hydroxyphe-nyl)benzotriazole, 2-(2'-hydroxy-5'-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-methyiphe-nyl)-5-chloro-benzotriazole, 2-(3'-sec-butyl-5'-tert-butyl-2'-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-4'-octyloxyphenyl)benzotriazole, 2-(3',5'-di-tert-amyl-2'-hydroxyphenyl)benzotriazole, 2-(3',5'-bis-(a,a-dinnethylbenzyl)-2'-hydroxyphenyl)benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-octyloxycarbonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3'-tert-butyl-5'-[2-(2-ethylhexyl-oxy)-carbonylethyl]-2'-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-methoxycarbonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-meth-oxycarbonylethyl)phenyl)benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-octyloxycarbonyl-ethyl)phenyl)benzotriazole, 2-(3'-tert-butyl-5'-[2-(2-ethylhexyloxy)carbonylethyl]-2'-hydroxy-phenyl)benzotriazole, 2-(3'-dodecyl-2'-hydroxy-5'-methylphenyl)benzotriazoie, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-isooctyloxycarbonylethyl)phenylbenzotriazole, 2,2'-methylene-bis[4-( 1,1,3,3-tetramethylbutyl)-6-benzotriazole-2-ylphenol]; the transesterification product of 2-[3'-tert-bu-tyl-5'-(2-methoxycarbonylethyl)-2'-hydroxyphenyl]-2H-benzotriazole with polyethylene glycol
300; [R-CHjCHg—COO-CH2CH2-3- ■ where R = 3'-tert-butyl-4'-hydroxy-5'-2H-benzotri-
azol-2-ylphenyl, 2-[2'-hydroxy-3'-(a,a-dlmethylbenzyl)-5'-(1,1,3,3-tetramethylbutyl)-phenyl]-benzotriazole; 2-[2'-hydroxy-3'-(1,1,3,3-tetramethylbutyl)-5'-(a,a-dimethylbenzyl)-phenyl]ben-zotriazole.
2.2. 2-Hvdroxvbenzophenones. for example the 4-hydroxy, 4-methoxy, 4-octyloxy, 4-decyl-oxy, 4-dodecyloxy, 4-benzyloxy, 4,2',4'-trihydroxy and 2'-hydroxy-4,4'-dimethoxy derivatives.
2.3. Esters of substituted and unsubstituted benzoic acids, for example 4-tert-butyl-phenyl sahcylate, phenyl sahcylate, octylphenyl sahcylate, dibenzoyi resorcinol, bis(4-tert-butylben-zoyl)resorcinol, benzoyl resorcinol, 2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzo-ate, hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl 3,5-di-tert-butyl-4-hydroxyben-zoate, 2-methyl-4,6-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate.
2.4. Acrvlates. for example ethyl a-cyano-p,p-diphenylacrylate, isooctyl a-cyano-p,p-diphe-nylacrylate, methyl a-carbomethoxycinnamate, methyl a-cyano-p-methyl-p-methoxycinna-mate, butyl a-cyano-p-methyl-p-methoxy-cinnamate, methyl a-carbomethoxy-p-methoxycin-

namate, N-(p-carbomethoxy-p-cyanovinyl)-2-methyhndohne, neopentyl tetra(a-cyano-p,p-di-phenylacrylate.
2.5. Nickel compounds, for example nickel complexes of 2,2'-thio-bls[4-(1,1,3,3-tetramethyl-butyl)phenol], such as the 1:1 or 1:2 complex, with or without additional hgands such as n-butylamine, triethanolamine or N-cyclohexyldiethanolamine, nickel dibutyldithiocarbamate, nickel salts of the monoalkyi esters, e.g. the methyl or ethyl ester, of 4-hydroxy-3,5-di-tert-butylbenzylphosphonic acid, nickel complexes of ketoximes, e.g. of 2-hydroxy-4-methylphe-nylundecylketoxime, nickel complexes of 1-phenyl-4-lauroyl-5-hydroxypyrazole, with or with¬out additional hgands.
2.6. Stericallv hindered amines, for example bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)succinate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1 -octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperi-dyl) n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensate of 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, hnear or cychc condensates of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-tert-octylamino-2,6-di-chloro-1,3,5-triazine, tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate, tetrakis(2,2,6,6-tetra-methyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, 1,1'-(1,2-ethanediyl)-bis(3,3,5,5-tetrame-thylpiperazinone), 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethyl-piperidine, bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)-malonate, 3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, bis(1-octyl-oxy-2,2,6,6-tetramethylplperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)succi-nate, hnear or cychc condensates of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylene-diamine and 4-morphohno-2,6-dichloro-1,3,5-triazlne, the condensate of 2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)-ethane, the condensate of 2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)ethane, 8-acetyl-3-dodecyl-7,7,9,9-tetrame-thyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, 3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyr-rohdine-2,5-dione, 3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperldyl)pyrrohdine-2,5-dione, a mixture of 4-hexadecyloxy- and 4-stearyloxy-2,2,6,6-tetramethylpiperidine, a condensate of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, a condensate of 1,2-bis(3-aminopropylamino)ethane and 2,4,6-trlchloro-1,3,5-triazine as well as 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No.

[136504-96-6]); a condensate of 1,6-hexanediamine and 2,4,6-trichloro-1,3,5-triazine as well
as N,N-dibutylamlne and 4-butylamino-2,2,6,6-tetramethylplperidine (CAS Reg. No. [192268-
64-7]); N-(2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsucclnimide, N-(1,2,2,6,6-pentamethyl-4-
piperldyl)-n-dodecylsuccinimide, 2-undecyl-7,7,9,9-tetramethyl-1 -oxa-3,8-diaza-4-oxo-splro-
[4,5]decane, a reaction product of 7,7,9,9-tetranriethyl-2-cycloundecyl-1-oxa-3,8-dlaza-4-oxo-
spiro-[4,5]decane and epichlorohydrin, 1,1-bis(1,2,2,6,6-pentamethyl-4-plperidyloxycarbo-
nyl)-2-(4-methoxyphenyl)ethene, N,N'-bis-formyl-N,N'-bis(2,2,6,6-tetramethyl-4-piperldyl)-
hexamethylenediamlne, a diester of 4-methoxymethylenemalonlc acid with 1,2,2,6,6-
pentamethyl-4-hydroxypiperldlne, poly[methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4-plperi-
dyl)]siloxane, a reaction product of maleic add anhydrlde-a-olefin copolymer with 2,2,6,6-
tetramethyl-4-aminopiperldlne or 1,2,2,6,6-pentamethyl-4-amlnopiperidine, 2,4-bls[N-(1-
cyclohexyloxy-2,2,6,6-tetramethylplperidine-4-yl)-N-butylamino]-6-(2-hydroxyethyl)amlno-
1,3,5-triazine, 1 -(2-hydroxy-2-methylpropoxy)-4-octadecanoyloxy-2,2,6,6-tetramethylpiperl-
dlne, 5-(2-ethylhexanoyl)oxymethyl-3,3,5-trimethyl-2-nnorphollnone, Sanduvor (Clarlant; CAS
Reg. No. 106917-31-1], 5-(2-ethylhexanoyl)oxymethyl-3,3,5-trlmethyl-2-morphohnone, the
reaction product of 2,4-bis[(1-cyclohexyloxy-2,2,6,6-plperidlne-4-yl)butylamino]-6-chloro-s-
triazlne with N,N'-bls(3-aminopropyl)ethylenedlamine), 1,3,5-trls(N-cyclohexyl-N-(2,2,6,6-
tetramethylplperazlne-3-one-4-yl)amino)-s-triazine, 1,3,5-trls(N-cyclohexyl-N-(1,2,2,6,6-
pentamethylplperazlne-3-one-4-yl)amlno)-s-triazlne.
2.7. Oxamides. for example 4,4'-dioctyloxyoxanihde, 2,2'-diethoxyoxanihde, 2,2'-dioctyloxy-5,5'-dl-tert-butoxanillde, 2,2'-dldodecyloxy-5,5'-di-tert-butoxanihde, 2-ethoxy-2'-ethyloxanlllde, N,N'-bls(3-dimethylaminopropyl)oxamide, 2-ethoxy-5-tert-butyl-2'-ethoxanihde and its mixture with 2-ethoxy-2'-ethyl-5,4'-di-tert-butoxaniiide, mixtures of o- and p-methoxy-disubstituted oxanihdes and mixtures of o- and p-ethoxy-disubstltuted oxanllldes.
2.8. 2-(2-Hvdroxvphenvn-1.3.5-triazines. for example 2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-octyloxyphenyI)-4,6-bls(2,4-dimethylphenyl)-1,3,5-triazlne, 2-(2,4-dlhydroxyphenyl)-4,6-bis(2,4-dlmethylphenyl)-1,3,5-trlazine, 2,4-bls(2-hydroxy-4-propyl-oxyphenyl)-6-(2,4-dlmethyiphenyl)-1,3,5-triazlne, 2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bls(2,4-dlmethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dlmethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropoxy)phenyl]-4,6-bis(2,4-dlmethyl)-1,3,5-trlazine, 2-[2-hydroxy-4-(2-hydroxy-3-octyloxypropyloxy)phenyl]-4,6-bls(2,4-dimethy!)-1,3,5-trlazlne, 2-[4-

(clodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-
1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxypropoxy)phenyl]-4,6-bis(2,4-dimethyl-
phenyl)-1,3,5-tria2ine, 2-(2-hydroxy-4-hexyloxy)phenyl-4,6-diphenyl-1,3,5-triazine, 2-(2-hydr-
oxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2,4,6-tris[2-hydroxy-4-(3-butoxy-2-
hydroxypropoxy)phenyl]-1,3,5-triazine, 2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine, 2-{2-hydroxy-4-[3-(2-ethyihexyl-1-oxy)-2-hydroxypropyloxy]phenyl}-4,6-bis(2,4-dimethyiphenyl)-1,3,5-triazine, 2,4-bis(4-[2-ethylhexyloxy]-2-hydroxyphenyi)-6-(4-methoxy-p[ienyl)-1,3,5-triazine.
3. IVIetal deactivators, for example N,N'-diphenyloxamide, N-sahcylal-N'-sahcyloyI hydrazine, N,N'-bis(sahcyloyl)hiydrazine, N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine, 3-sahcyloylamino-1,2,4-triazole, bis(benzyhdene)oxalyl dihydrazide, oxanihde, isophttialoyl dihydrazide, sebacoyi bisphenylhydrazide, N,N'-diacetyladipoyl ditiydrazide, N,N'-bis(sahcyl-oyl)oxalyl dihydrazide, N,N'-bis(sahcyloyl)thiopropionyl ditiydrazlde.
4. Phosphites and phosphonites. for example triphenyl phosphite, diphenylall The following phosphites are especially preferred:
Tris(2,4-di-tert-butylpheny!) phosphite (lrgafos®168, Ciba Specialty Chemicals Inc.), tris(no-nylphenyl) phosphite.

5. Hvdroxvlamines. for example N,N-dibenzylhydroxylamine, N,N-diethylhydroxylamine, N,N-
dioctylhydroxylamine, N,N-dilaurylhydroxylamine, N,N-ditetradecylhydroxylamine, N,N-
dihexadecylhydroxylamine, N,N-dioctadecylhydroxylamine, N-hexadecyl-N-octadecylhydrox-
ylamine, N-heptadecyl-N-octadecylhydroxylamine, N,N-dialkylhydroxylamine derived from
hydrogenated tallow amine.
6. Nitrones, for example, N-benzyl-alptia-pfienylnitrone, N-etiiyl-alpha-methylnitrone, N-octyl-
alpha-heptylnitrone, N-lauryl-alpha-undecylnitrone, N-tetradecyl-alpha-tridecylnnitrone, N-
hexadecyl-alpha-pentadecylnitrone, N-octadecyl-alpha-heptadecyinitrone, N-hexadecyl-al-
piia-heptadecylnitrone, N-ocatadecyl-alpha-pentadecylnitrone, N-iieptadecyl-alpha-hepta-
decylnitrone, N-octadecyl-alpha-hexadecylnitrone, nitrone derived from N,N-dialkylhydroxyl-
amine derived from hydrogenated tallow amine.
7. Thiosvneroists. for example dilauryl thiodipropionate, dimistryl thiodipropionate, distearyl thiodipropionate or distearyl disulfide.
8. Peroxide scavengers, for example esters of p-thiodipropionic acid, for example the lauryl, stearyl, myristyl or tridecyl esters, mercaptobenzimidazole or the zinc salt of 2-mercapto-benzimidazole, zinc dibutyldithiocarbamate, dioctadecyl disulfide, pentaerythritol tetrakis(p-dodecylmercapto)propionate.
9. Polvamide stabihzers, for example copper salts in combination with iodides and/or phos¬
phorus compounds and salts of divalent manganese.
10. Basic co-stabihzers, for example melamine, polyvinylpyrrohdone, dicyandiamide, triallyl
cyanurate, urea derivatives, hydrazine derivatives, amines, polyamides, polyurethanes, alkah

metal salts and alkahne earth metal salts of higher fatty acids, for example calcium stearate, zinc stearate, magnesium behenate, magnesium stearate, sodium ricinoleate and potassium palmitate, antimony pyrocatecholate or zinc pyrocatecholate.
11 ■ Nucleating agents, for example inorganic substances, such as talcum, metal oxides, such as titanium dioxide or magnesium oxide, phosphates, carbonates or sulfates of, preferably, alkahne earth metals; organic compounds, such as mono- or polycarboxyhc acids and the salts thereof, e.g. 4-tert-butylbenzoic acid, adipic acid, diphenylacetic acid, sodium succinate or sodium benzoate; polymeric compounds, such as ionic copolymers (ionomers). Especially preferred are 1,3:2,4-bis(3',4'-dimethylbenzyhdene)sorbitol, 1,3:2,4-di(paramethyl-dibenzyhdene)sorbitol, and 1,3:2,4-di(benzyhdene)sorbitol.
12. Fillers and reinforcing agents, for example calcium carbonate, sihcates, glass fibres, glass beads, asbestos, talc, kaohn, mica, barium sulfate, metal oxides and hydroxides, car¬bon black, graphite, wood flour and flours or fibers of other natural products, synthetic fibers.
13. Other additives, for example plasticisers, lubricants, emulsifiers, pigments, rheology additives, catalysts, flow-control agents, optical brighteners, flameproofing agents, antistatic agents and blowing agents.
14. Benzofuranones and indohnones. for example those disclosed in U.S. 4,325,863; U.S. 4,338,244; U.S. 5,175,312; U.S. 5,216,052; U.S. 5,252,643; DE-A-4316611; DE-A-4316622; DE-A-4316876; EP-A-0589839, EP-A-0591102; EP-A-1291384 or 3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-tert-butylbenzofuran-2-one, 5,7-di-tert-butyl-3-[4-(2-stearoyloxy-ethoxy)phenyl]benzofuran-2-one, 3,3'-bis[5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)ben-zofuran-2-one], 5,7-di-tert-butyl-3-(4-ethoxyphenyl)benzofuran-2-one, 3-(4-acetoxy-3,5-di-methylphenyl)-5,7-di-tert-butyibenzofuran-2-one, 3-(3,5-dimethyl-4-pivaloyloxyphenyI)-5,7-di-tert-butylbenzofuran-2-one, 3-(3,4-dimethylphenyl)-5,7-di-tert-butylbenzofuran-2-one, 3-(2,3-dimethylphenyl)-5,7-di-tert-butylbenzofuran-2-one, 3-(2-acetyl-5-isooctylphenyl)-5-isooctyl-benzofuran-2-one.
The above additives are in general apphed in an amount between 0.01 and 2% by weight based on the weight of the thermoplastic polymer.

A further aspect of the invention is a method for enlarging the optimal peak temperature range in rotational molding processes of thermoplastic polymers by the use of a secondary sterically hindered amine compound as processing additive.
Accordingly disclosed is a method for enlarging the processing window towards higher peak internal air temperatures in rotational molding processes of thermoplastic polymers, which method comprises incorporating a secondary sterically hindered amine into a thermoplastic polymer and subjecting the polymer to a rotational molding process..
Yet another embodiment of the invention is a process for the production of thermoplastic
hollow articles, which process comprises
mixing a thermoplastic polymer with a secondary sterically hindered amine and subjecting this mixture to a rotational molding process where the peak internal
temperature range is from about 215 to about 250C,
wherein when the thermoplastic polymer is polyethylene, the hindered amine is not a
hnear or cychc condensate of N,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)-
hexamethylenediamine and 4-morphohno-2,6-dichloro-1,3,5-triazine.
Definitions and preferences given above apply also for the other aspect of the invention.
The following examples illustrate the invention.
Example 1: Preparation of Polyolefin Hollow Articles by a rotational molding process 100 parts medium density polyethylene, copolymerized with hexene (nominal melt index 3.3 g/10 min., density 0.938 g/cm^) are dry blended with 0.050 parts of zinc stearate and a combination of additional stabihzers as given in Table 1. The mixtures are melt compounded into pellets at 190 °C in a Superior/MPM extruder using a 24:1 L/D screw with Maddock mixing head at 100 rpm. The compounded pellets are ground to a uniform particle size (150-500 |hm) prior to the rotational molding process. This grinding step increases the surface area of the particles leading to faster heat absorption, and thus reducing overall energy consumption. The rotational molding process is performed in laboratory scale equipment FSP M20 "Clamshell". The ground resin is placed in an aluminum mold, which is rotated biaxially in a gas fired oven. Hot air is circulated by blowers in the chamber while the temperature is increased to 274°C. This temperature is maintained for a specific time, which

will give a certain peak internal air temperature (PIAT) as given in Table 2. Subsequently, the oven is opened and while still rotating, the mold is cooled with forced air circulation for 7.3 minutes, followed by water spray mist for 1.5 minutes, air coohng for 2 minutes, water spray 2.9 minutes and air coohng 4.4 minutes. Throughout the entire heating and coohng cycles, i the speed of the major axis is maintained at 6 rpm with a 4 : 1 ratio of rotation. After the coohng cycles, the mold is opened and the hollow object removed.
The processing range is defined as peak internal air temperature range (PIAT) in which a part with high impact strength can be produced. The impact strength is measured with the Dynatup Falhng weight method (25lb/20"") according to ASTM D-3763 at -40° C.

The data clearly indicate that the useful process range can be significantly shifted towards higher temperatures by the use of secondary sterically hindered amine compounds without sacrificing the impact strength.
Example 2: Preparation of Polyolefin Hollow Articles by a rotational molding process
The procedure given in example 1 has been repeated with further additives as outhned in
Table 3. The results are presented in Table 4

Whereas the processing temperature, as measured by the peak internal air temperature, (PIAT) should not exceed 198° C if no sterically hindered amine is present, 210° are acceptable when a tertiary sterically hindered amine is present. However, this temperature can further be extended up to 221° C, when, according to the invention, a secondary sterically hindered amine has been added.
®Irganox 3114 is a phenohc antioxidant from Ciba Specialty Chemicals,
®Irgastab FS042 is N,N-di(tallow alkyl)hydroxylamine from Ciba Specialty Chemicals,
®Irgafos 168 is a trisaryl phosphite from Ciba Specialty Chemicals,
®Tinuvin 622 is a tertiary sterically hindered amine from Ciba Specialty Chemicals,
®Cyasorb UV 3346 is a secondary sterically hindered amine from Cytech Industries,
®Chimassorb 944 is a secondary sterically hindered amine from Ciba Specialty Chemicals,
®Chimassorb 2020 is a secondary sterically hindered amine from Ciba Specialty Chemicals,
®Chimassorb 119 is a tertiary sterically hindered amine from Ciba Specialty Chemicals,
®Hostavin N 30 is a tertiary sterically hindered amine from Clariant,
®Tinuvin 770 is a secondary sterically hindered amine from Ciba Specialty Chemicals,
®Tinuvin 783 is a mixture of a secondary and tertiary sterically hindered amine from Ciba
Specialty Chemicals.

Claims
1. Use of a secondary sterically hindered amine compound as processing additive for
enlarging the processing window towards higher peak internal air temperatures in rotational
molding processes of thermoplastic polymers.
2. Use according to claim 1 wherein the sterically hindered amine is a compound containing
at least one group of the formula (I) or (II)

in which
* indicates a bond
G is hydrogen or methyl, and
G1 and G2, independently of one another, are hydrogen, methyl or together are a substituent
=0.
3. Use according to claim 2 wherein the sterically hindered amine is a compound containing
at least one group of formula (la).

4. Use according to claim 1 wherein the sterically hindered amine compound is added in an
amount from 0.01 to 5% by weight, based on the weight of the thermoplastic polymer.
5. Use according to claim 1 wherein the thermoplastic polymer is a polyolefin,
polyvinylchloride or polyamide.

6. Use according to claim 1 wherein the thermoplastic polymer is polyethylene.
7. Use according to claim 1 wherein the peak internal air temperature range in rotational
molding processes is enlarged up to 10 to 50° C towards higher temperatures.
8. Use according to claim 1 wherein the peak internal air temperature range is from 215 to 250° C
9. Use according to claim 1 wherein in the rotational molding process an additional stabilizer selected from the group consisting of a UV-absorber, a sterically hindered amine, different from that of formula (I) or (II), a phenolic antioxidant, a phosphite or phosphonite and a benzofuranone or indolinone is present.
10. A method for enlarging the processing window towards higher peak internal air
temperatures In rotational molding processes of thermoplastic polymers,
which method comprises incorporating a secondary sterically hindered amine into a thermoplastic polymer and subjecting the polymer to a rotational molding process.
11. A method of using a secondary sterically hindered amine compound as processing
additive for enlarging the processing window towards higher peak internal air temperatures in
rotational molding processes of thermoplastic polymers.

Documents:

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Patent Number

270136

Indian Patent Application Number

4024/CHENP/2008

PG Journal Number

49/2015

Publication Date

04-Dec-2015

Grant Date

30-Nov-2015

Date of Filing

31-Jul-2008

Name of Patentee

BASF SE

Applicant Address

KLYBECKSTRASSE 141, CH-4057 BASEL,

Inventors:

#	Inventor's Name	Inventor's Address
1	THURMER, ANDREAS,	FAULACKER 9, 79576 WEIL AM RHEIN,
2	MINDER, ERNST,	BERNHARDSMATTWEG 1, CH-4450 SISSACH,
3	THURMER, ANDREAS,	FAULACKER 9, 79576 WEIL AM RHEIN,
4	BOTKIN, James, Harold	28 Reservoir Hill Road, Parsonsfield, ME -04047,

PCT International Classification Number

C08K5/3435

PCT International Application Number

PCT/EP07/50678

PCT International Filing date

2007-01-24

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	6101127.6	2006-02-01	EUROPEAN UNION