MX2008007217A - Fast curing aliphatic rim elastomers - Google Patents

Abstract

This invention relates to polyurethane elastomers and to a process for their production. These elastomers comprise the reaction product of a (cyclo)aliphatic isocyanate component having an NCO group content of about 20 to about 45%, with an isocyanate-reactive component comprising one or more polyether polyols which is free of amine groups, and a low molecular weight organic compound containing two hydroxyl groups and which is free of amine groups, in the presence of one or more catalysts.

Description

ELASTOMEROS RIM ALIFATICOS OF QUICK CURING BACKGROUND OF THE INVENTION This invention relates to rapidly curing aliphatic RIM elastomers and to a process for their production. The production of molded articles of polyurethane through the technique of reactive injection molding (ie RIM) is well known and is described, for example, in U.S. Patent No. 4,218,543. The RIM procedure involves a mold loading technique by means of which the highly reactive liquid starting components are injected into the mold in a very short time by means of a high-performance, high-pressure dosing apparatus after they have been mixed in the so-called "positively controlled mixing heads". In the production of molded articles of polyurethane through the RIM process, the reaction mixture generally comprises a part A with a base of polyisocyanates and a part B with a base of organic compounds containing hydrogen atoms reactive with isocyanate, in addition to extenders of suitable chain, catalysts, blowing agents, and other additives. The Polyisocyanates which are suitable for a commercial RIM process are aromatic isocyanates such as, for example, 4,4'-diphenylmethane diisocyanate (ie MDI). While different patents describe cycloaliphatic isocyanates broadly in a long list of isocyanates that are described as being suitable for use in a RIM process, few patents have any working examples where a cycloaliphatic isocyanate is used. U.S. Patent No. 4,772,639 describes a process for the production of molded articles of polyurethane by reacting organic polyisocyanates with organic compounds containing isocyanate-reactive hydrogen atoms in the presence of catalysts and auxiliary agents within a mold closed. The isocyanate component is based on (a) mixtures of (i) 1-isocyanato-3, 3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), and (ii) polyisocyanates containing isocyanurate groups prepared by the trimerization of a portion of the isocyanate groups of 1,6-diisocyanatohexane, or (a2) (i) IPDI and (iii) polyisocyanates containing isocyanurate groups prepared by trimerization of a portion of the isocyanate groups of a mixture of 1,6- diisocyanatohexane and IPDI. These reaction mixtures are widely described as being suitable for transformation by RIM. U.S. Patent No. 4,642,320 describes a process for the preparation of a molded polymer comprising reacting within a closed mold a reaction mixture comprising (a) an active hydrogen-containing material comprising a finished polyether in primary or secondary amine having an average equivalent weight of at least 500, (b) at least one chain extender, and (c) a polyisocyanate (cyclo) aliphatic, polyisothiocyanate, or mixture thereof, wherein the NCX index is from about 0.6 to 1.5. This method requires that component (a) have at least 25%, and preferably 50% of its active hydrogen atoms present in the form of amine hydrogens. All the examples describe a system based on an HDI prepolymer with polyethers terminated in amine and diethyl toluene diamine at high mold temperatures and long demold times. U.S. Patent No. 4,764,543 discloses aliphatic RIM systems utilizing aliphatic polyamines that react very rapidly. This patent is restricted to total polyurea systems based on chain extenders which are diamines and cycloaliphatic polyethers which are polyethers terminated in amine, with a polyisocyanate linked aliphatically. RIM systems are also described in U.S. Patent No. 4,269,945. These systems are based on compositions comprising a polyisocyanate, a hydroxyl-containing polyol, and a specific chain extender. The specific chain extender comprises (1) at least one component selected from the group consisting of (a) a hydroxyl-containing substance that essentially lacks aliphatic amine hydrogen atoms, and (b) substances containing aromatic amines containing at least two aromatic amine hydrogen atoms and essentially lacking aliphatic amine hydrogen atoms; and (2) at least one substance containing aliphatic amines having at least one primary amine group and a mean aliphatic amine hydrogen functionality of about 2 to 16. Both the aromatic polyisocyanates and the (cyclo) aliphatic polyisocyanates are described as being suitable for this procedure. All the working examples in this patent use aromatic isocyanates that They can be polymeric in nature. U.S. Patent No. 5,260,346 also discloses reaction systems for preparing elastomers through the RIM process. These systems require an allophanate-modified polyisocyanate, a polyol containing hydroxyl groups, and an aromatic polyamine in which at least one of the ortho positions with respect to the amine group is substituted with a lower alkyl substituent. U.S. Patent No. 5,502,147 describes an aliphatic (cyclo) isocyanate based on the RI systems. These (cyclo) aliphatic isocyanates have a viscosity of less than 20,000 mPa. s at 25 ° C, an NCO functionality of 2.3 to 4.0, and are modified with isocyanurate groups, biuret groups, urethane groups, allophanate groups, carbodiimide groups, oxydiazine-trione groups, uretdione groups, and combinations thereof. Part B comprises a high molecular weight polyol and a low molecular weight chain extender in which the ratio 0H: NH is from 1: 1 to 25: 1. U.S. Patent No. 5,502,150, which is commonly assigned, discloses a RIM process utilizing a hexamethylene diisocyanate prepolymer having a functionality of less than 2.3, an NCO content of 5 to %, and a monomer content of less than 2% by weight. This prepolymer is reacted with a high molecular weight isocyanate-reactive compound, a chain extender selected from diols and aminoalcohols, and a crosslinking compound with a hydroxyl base containing not more than one aliphatic amine hydrogen atom. Light stable polyurethanes are also described in U.S. Patent Nos. 5,656,677 and 6,242,555. The polyurethanes of U.S. Patent No. 5,656,677 comprise the reaction product of a (cyclo) aliphatic isocyanate with a compound containing isocyanate-reactive hydrogen atoms, in the presence of a chain extender and / or an agent of cross-linking, and a specific catalyst system. The catalyst system comprises 1) at least one organic lead compound, 2) at least one organic bismuth compound, and / or 3) at least one organic tin compound. The stable elastomers in the light of U.S. Patent No. 6,242,555 comprise the reaction product of A) a trimeric / monomer mixture of isophorone diisocyanate having an NCO group content of 24.5 to 34%, with B) an isocyanate-reactive component, in the presence of C) at less a catalyst selected from compounds of organoplome (II), organobismuto (III) and organotin (IV). The advantages of the present invention include improved curing, and simplified catalysis, without the need for a catalyst with a lead base. The present invention also does not require polyols with an amine base as part of the isocyanate reactive component.

COMPENDIUM OF THE INVENTION This invention relates to rapidly curing aliphatic RIM elastomers and to a process for their production. These polyurethane elastomers comprise the reaction product of: (A) an isocyanate component having an NCO group content of about 20 to about 45% by weight, a functionality of about 2.0 to about 2.7, preferably about 2.1 to about 2.3, and comprising a trimerized (cyclo) aliphatic polyisocyanate, with the proviso that (i) when the polyisocyanate (cyclo) aliphatic is isophorone diisocyanate trimerized, component (A) contains less than 20% (preferably less than 10% and more preferably less than 5%) by weight of trimerized hexamethylene diisocyanate, and (ii) when the (cyclo) aliphatic polyisocyanate is trimerized hexamethylene diisocyanate, component (A) contains less than 10% by weight. Weight of isophorone diisocyanate; with (B) an isocyanate-reactive component comprising: (1) from about 70 to about 90% by weight, based on 100% by weight of (B), of one or more polyether polyols having a functionality of about 2 to about 8 (preferably 2 to 4), a molecular weight of about 1000 to about 8000 (preferably 2000 to 6000) and lack amine groups (primary, secondary and / or tertiary); and (2) from about 10 to about 30% by weight, based on 100% by weight of (B), of one or more organic compounds having a molecular weight of from about 62 to about 400, (preferably 62 to 90) , who have a hydroxyl functionality from 2 to 3, and lack amine groups (primary, secondary and / or tertiary), in the presence of (C) one or more catalysts corresponding to the formula: where: m: represents an integer from 3 to 8, preferably from 3 to 4; and n: represents an integer from 3 to 8, preferably from 3 to 5, and, optionally, (D) one or more additives (including ultraviolet stabilizers, pigments, etc.). The relative amounts of the components (A) and (B) are such that the isocyanate number of the resulting elastomer ranges from about 100 to about 120.

In an alternative embodiment of the present invention, the polyisocyanate component (A) comprises a prepolymer comprising the reaction product of (1) at least about 65% to less than 100% by weight, based on 100% by weight of the component polyisocyanate, of the trimerized (cyclo) aliphatic polyisocyanate described above, and (2) of more than 0% to about 35% by weight, based on 100% by weight of the polyisocyanate component, of an isocyanate-reactive component having about to about 6, preferably 2 to 4 hydroxyl groups capable of reacting with the NCO groups of (1) and a molecular weight of about 60 to about 4,000, wherein the NCO group content of the prepolymer is from about 10% to about 35% The process for the production of these polyurethane elastomers comprises reacting a reaction mixture by a reactive injection molding technique. This reaction mixture corresponds to that described above.

DETAILED DESCRIPTION OF THE INVENTION Suitable (cyclo) aliphatic polyisocyanates to be used as component (A) in the present invention include isocyanurates of a (cyclo) aliphatic diisocyanate such as, for example, 1,4-tetramethylene diisocyanate, diisocyanate of 1, 6 hexamethylene, 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 1,3- and 1,4-cyclohexanediisocyanate, 1-isocyanato-2-isocyanatomethylcyclopentane, 1-isocyanate -3-isocyanato-methyl-3,5,5-trimethylcyclohexane (isophorone diisocyanate or IPDI), bis- (4-isocyanatocyclohexyl) -methane, 2,4'-dicyclohexylmethane diisocyanate, 1,3- and 1,4- bis- (isocyanatomethyl) -cciohexane, bis- (4-isocyanato-3-methylcyclohexyl) -methane, a, a, a ', a'-tetramethyl-1, 3- and / or -1, 4-xylylene diisocyanate, l-isocyanato-l-methyl-4 (3) -isocyanatomethylcyclohexane, 4,4'-dicyclohexylmethane diisocyanate, 2,4- and / or, 6-hexahydrotoluylene diisocyanate, and mixtures thereof. It is preferred that the isocyanate comprises 1, 6-hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1-isocyanato-3-isocyanatomethyl-3, 5, 5-trimethylcyclohexane, etc. The most preferred isocyanates include hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and 1- isocyanate-3-isocyanatomethyl-3, 3, 5-trimethylcyanohexane. The polyisocyanurates or polyisocyanates containing isocyanurate groups, ie the so-called polyisocyanate trimers, are suitable as component (A). Suitable trimers of the polyisocyanates include compounds that can be prepared by methods such as those described, for example, in U.S. Patent Nos. 4,288,586 and 4,324,879, the disclosures of which are incorporated herein by reference; European Patents 3,765, 10,589 and 47,452, the descriptions of which are incorporated herein by reference; and German Patent Publication Nos. 2,616,416, incorporated herein by reference. The isocyanates-isocyanurates generally have an NCO functionality of from 2.0 to 2.7, preferably from 2.1 to 2.3, and an NCO content of from 20 to 45%, preferably from 20 to 40% by weight, more preferably from about 20 to about 35%, and most preferably from about 25 to about 31%. The hexamethylene diisocyanate (HDI) trimers typically have an NCO functionality of 2.0 to 2.7, preferably 2.1 to 2.3, and an NCO content of 30 to 45% and preferably 35 to 45% in weight. The trimers of dicyclohexyl diisocyanate (rMDI) typically have an NCO functionality of 2.0 to 2.7, preferably 2.1 to 2.3, and an NCO content of 19 to 31% and preferably 20 to 30% by weight. The isophorone diisocyanate (IPDI) trimers typically have an NCO functionality of 2.0 to 2.7, preferably 2.1 to 2.3, and an NCO content of 22 to 37% and preferably 26 to 32% in weight. The prepolymers of these polyisocyanates, and in particular of the trimerized polyisocyanates described above, are also suitable for use as a component (A) according to the present invention. The prepolymer preparation of the polyisocyanates of the present invention comprises reacting an aliphatic (cyclo) polyisocyanate as described above with a suitable isocyanate-reactive compound, such as, for example, a polyether polyol, polyester polyol, or a low weight polyol molecular. Isocyanate-reactive compounds suitable for the present invention typically have a molecular weight of from about 60 to about 4,000 and have a hydroxyl functionality of from about 2 to about 6. In accordance with the present invention, the compounds Isocyanate reagents used to make prepolymers typically have a molecular weight of at least about 60, preferably at least about 75, more preferably at least about 100 and most preferably at least about 130. Isocyanate-reactive compounds also typically have a molecular weight of less than or equal to about 4,000, preferably less than or equal to 1,000, more preferably less than or equal to about 400 and most preferably less than or equal to about 200. The isocyanate-reactive compounds may have a molecular weight ranging from any combination of these superior and inferior values, inclusive, p. ex. from about 60 to about 4,000, preferably from about 75 to about 1,000, more preferably from about 100 to about 400, and most preferably from about 130 to about 200. Likewise, the isocyanate-reactive compounds used to make prepolymers typically have a functionality of at least about 2, and typically less than or equal to about 6, preferably less of or equal to about 4, and more preferably less than or equal to about 3. The isocyanate-reactive compounds may have a functionality, which ranges from any combination of these higher and lower values, inclusive, e.g. ex. from about 2 to about 6, preferably from about 2 to about 4, and more preferably from about 2 to about 3. Examples of suitable isocyanate-reactive compounds include polyether polyols, polyester polyols, low molecular weight polyols, etc. All these compounds are known in the field of polyurethane chemistry. Suitable polyether polyols can be prepared by the reaction of suitable starting compounds contag hydrogen atoms reactive with alkylene oxides such as, for example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran, epichlorohydrin, and its mixtures. Suitable starting compounds contag reactive hydrogen atoms include compounds such as, for example, ethylene glycol, propylene glycol, butylene glycol, hexanediol, octanediol, neopentyl glycol, cyclohexanedimethanol, 2-methyl-1, 3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, methylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol, polybutylene glycol, glycerin, trimethylolpropane, pentaerythritol, water, methanol, ethanol, 1, 2, 6-hexanetriol, 1,2,4-butanetriol, trimethylolethane, mannitol, sorbitol, methylglycoside, sucrose, phenol, resorcinol, hydroquinone, 1,1,1- or 1,1,2-tris - (hydroxyphenyl) ethane, etc. Suitable polyester polyols include, for example, the reaction products of polyhydric alcohols, preferably dihydric alcohols (optionally in the presence of trihydric alcohols), with polyvalent carboxylic acids, preferably divalent. Instead of using the free carboxylic acids, it is also possible to use the corresponding anhydrides of polycarboxylic acids or polycarboxylic acid esters of corresponding lower alcohols or their mixtures to produce the polyesters. The polycarboxylic acids can be aliphatic, cycloaliphatic, aromatic, and / or heterocyclic and can be unsaturated or substituted, for example, with halogen atoms. Polycarboxylic acids and polyols used to prepare the polyesters are known and described for example in U.S. Patent Nos. 4,098,731 and 3,726,952, incorporated herein by reference in its entirety. Polythioethers, polyacetals, polycarbonates and other suitable polyhydroxy compounds are also described in the previously identified US Patents. Finally, representative compounds of the many and varied which can be used according to the invention can be found, for example, in High Polymers, Volume XVI, "Polyurethanes, Chemistry and Technology," by Saunders-Frisch, Interscience Publishers, New York, London, Vol. I, 1962, pages 32-42 and 44-54, and Volume II, 1964, pages 5-6 and 198-199; and in Kunststoff-Handbuch, Vol. VII, Vieweg-Hochtlen, Carl Hanser Verlag, Munich, 1966, pages 45-71. Low molecular weight polyols suitable for preparing prepolymers include, for example, diols, triols, tetraols, and alkoxylation products thereof. These include 2-methyl-1,3-propanediol, ethylene glycol, 1,2- and 1,3-propanediol, 1,3- and 1,4- and 2,3-butanediol, 1,6-hexanediol, 1, 10 -decanodol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, glycerol, trimethylolpropane, neopentyl glycol, cyclohexanedimethanol, 2,2,4-trimethylpentane-1,3-diol, pentaerythritol, etc. Alkoxylation products of these same compounds can also be used to prepare prepolymers. According to the present invention, the preferred isocyanate-reactive compounds for forming prepolymers are trimethylolpropane and tripropylene glycol. As previously mentioned, preferred polyisocyanates include the (cyclo) aliphatic polyisocyanate trimers prepolymers. These polyisocyanates are prepared by first forming the (cyclo) aliphatic polyisocyanate containing an isocyanurate group that has been described above, and then reacting the polyisocyanate containing an isocyanurate group with a suitable isocyanate-reactive compound to form the prepolymer. The polyisocyanurate prepolymers suitable for the present invention typically have a NCO group content of about 10 to 35%, preferably about 12 to about 29%, and more preferably about 16 to about 24%, and a functionality from about 2 to about 6, preferably from about 2 to about 4. The preferred polyisocyanates to be trimerized are selected from the group consisting of hexamethylene diisocyanate, isophorone diisocyanate and dicyclohexylmethane diisocyanate. For trimerized HDI prepolymers, the large NCO group content is from 12 to 29, and the functionality is from 2.0 to 6.0; and the preferred NCO group content is from 16 to 24 and the preferred functionality is from 2.0 to 4.0; for the trimerized IPDI prepolymers, the broad NCO group content is from 12 to 29, and the functionality is from 2.0 to 6.0; the preferred NCO group content is from 16 to 24 and the preferred functionality is from 2.1 to 2.3; and for the trimerized rMDI prepolymers, the broad NCO group content is from 12 to 29, and the functionality is from 2.0 to 6.0; the preferred NCO group content is from 16 to 24 and the preferred functionality is from 2.0 to 4.0. In accordance with the present invention, the isocyanate moieties which can inherently result in the production of some / all of the isocyanates described above after the treatment are not suitable for the isocyanate component of the present specification. Such residues are undesirable by-products of the process for the production of the isocyanate components. Suitable compounds to be used as component (B) (1) according to the present invention include, for example, polyether polyols. High molecular weight polyethers suitable for use in accordance with the invention are known and can be obtained, for example, by polymerizing tetrahydrofuran or epoxides such as, for example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide. or epichlorohydrin in the presence of suitable catalysts, such as, for example, BF3 or KOH, or by chemically adding these epoxides, preferably ethylene oxide and propylene oxide, mixed, alone or in succession to suitable starting materials containing reactive hydrogen atoms. Examples of suitable starting compounds include, but are not limited to, propylene glycol, glycerin, ethylene glycol, butylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, water, trimethylolpropane, tetraethylene glycol, pentaerythritol, bisphenol A, sucrose, sorbitol, etc.

As would be appreciated by one of ordinary skill in the art, these types of polyether polyols contain relatively high amounts of unsaturation. Preferred polyethers include, for example, alkoxylation products (preferably ethylene oxide, propylene oxide or both) based on di- or tri- functional initiators such as, for example, water, ethylene glycol, propylene glycol, glycerin, trimethylolpropane, etc . The appropriate compounds that are to be used as (B) (1) according to the present invention include those ha a molecular weight of from about 1,000 to about 8,000, preferably 2,000 to about 6,000, and a hydroxyl functionality of from about 2 to about 8, and preferably from about 2 to about 4. In accordance with the present invention, compounds suitable for component (B) (1) in the present specification lack primary, secondary and / or tertiary amine groups. The appropriate compounds that are to be used as (B) (2) according to the present invention include those ha a molecular weight of about 62 to about 400, a hydroxyl functionality of about 2 or 3 and lacking primary, secondary and / or tertiary amine groups. These compounds preferably have a molecular weight of from about 62 to about 90. Some examples of suitable compounds to be used as component (B) (2) herein include compounds such as 2-methyl-1,3-propanediol. , ethylene glycol, 1,2- and 1,3-propanediol, 1,3- and 1,4- and 2,3-butanediol, 1,6-hexanediol, 1,10-decanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, cyclohexanedimethanol, and 2,2,4-trimethylpentane-1,3-diol, trimethylolpropane, pentaerythritol, glycerol. Preferred diols include, for example, ethylene glycol, and trimethylolpropane. According to the present invention, the reaction of the component (A) with the component (B) is in the presence of (C) one or more catalysts corresponding to the formula: where : m: represents an integer from 3 to 8, preferably from 3 to 4; and n: represents an integer from 3 to 8, preferably from 3 to 5; Some examples of suitable catalysts corresponding to the formula identified above include 1,8-diaza-7-bicyclo [5, 4, 0] undec-7-ene (ie DBU), 1,5-diazabicyclo [4, 4, 0] dec-5-ene (ie DBD), 1,5-diazabicyclo- [4, 3, 0] non-5-ene (ie DBN), 1,8-diazabicyclo [7.5.0] tetra -dec-8-ene, 1, 8 -diazabicyclo- [7, 4, 0] tridec-8-ene, 1,8-diazabicyclo [7,, 0] dodec-8-ene, etc.

According to the present invention, the amount of catalyst corresponding to the above structure present is such that there is at least from about 0.1% to about 6.0% by weight, preferably from about 0.5% to about 2.5. %, and more preferably from about 1% to about 1.5% by weight, based on 100% by weight of component (B). In accordance with the present invention, it is also possible that other catalysts which are known to be suitable for the preparation of polyurethanes may be present.

Suitable catalysts include, for example, metal carboxylate catalysts, metal halides, known ammonium, tin-sulfur carboxylates, and tertiary amine catalysts. Suitable metals for these catalysts include, but are not limited to, tin, bismuth, lead, mercury, etc. Of these catalysts, it is preferred to use tin carboxylates and / or tertiary amines combined with the "diazabicyclo" catalysts described above. Suitable metal carboxylates include tin carboxylates such as, for example, dimethyltin dilaurate, dibutyltin dilaurate, dibutyltin di-2-ethylhexoate, dibutyltin maleate, and bismuth carboxylates, such as, for example, bismuth trineodecanoate. Some suitable examples of metal halides include, for example, tin halides and particularly, tin chlorides such as, for example, dimethyltin dichloride and dibutyltin dichloride. Suitable examples of the ammonium carboxylates include, for example, trimethylhydroxyethylammonium 2-ethylhexanoate (i.e. TMR of Dabco). As previously mentioned, tin carboxylates such as, for example, dimethyltin dilaurate, and dilaurate of dibutyltin are preferred metal carboxylate catalysts to be used together with the above-described catalysts of the specified formula. Other suitable catalysts include tin-sulfur catalysts such as, for example, dialkyltin dilaurylmercaptides such as, for example, dibutyltin dilaurylmercaptide and dimethyltin dilaurylmercaptide. Some examples of suitable tertiary amine catalysts include compounds such as, for example, triethylamine, triethylenediamine, tributylamine, N-methyl-morpholine, N-ethylmorpholine, triethanolamine, triisopropanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, and N, N-dimethylethanolamine. . According to a preferred embodiment of the present invention, it is preferred to use a catalyst corresponding to the above-shown combined formula comprising one or more tin carboxylate catalysts. Preferred tin carboxylates comprise dimethyltin dilaurate and / or dibutyltin dilaurate. When a combination of two or more catalysts is used according to the preferred embodiment of the present invention, the total amount of both catalysts it must be generally in the quantities previously described. In other words, the total amount of all the catalysts present should be such that there is at least from about 0.1% to about 6.0% by weight of all the catalysts, preferably from about 0.5% to about 2.5. %, more preferably from about 1% to about 1.5% by weight of all the catalysts, based on 100% by weight of component (B). If the preferred combination of an amine catalyst having a structure corresponding to that described above and a tin carboxylate catalyst in the present invention is used, it is preferred that the amine catalyst (of the above structure) be present in an amount 50 to 90% by weight, and the tin carboxylate catalyst is present in an amount of 10 to 50% by weight, totaling the sum of 100% by weight by weight of the catalyst component. More specifically, this would typically produce the amine catalyst corresponding to the specified formula representing from 50 to 90% by weight from 0.1 to 6.0% by weight of the total catalyst; and the tin carboxylate catalyst representing from about 10 to about 50% by weight of 0.1 to 6.0% by weight of the total catalyst, totaling the sum of the% by weight of the individual catalysts 100% by weight of the catalysts. Suitable stabilizers for the present invention include light stabilizers that are considered to include any of the known compositions that are capable of preventing significant yellowing in the elastomers of the present invention. As used herein, it can be understood that the light stabilizers include amine light stabilizers with steric hindrance, ultraviolet (UV) absorbers, and / or antioxidants. Some examples of sterically hindered amine light stabilizers include, but are not limited to, compounds such as, for example, those derived from 2, 2, 6, 6-tetraalkylpiperidine radicals, other types of sterically hindered amines such as those containing morpholinones, piperazinones, piperazinodiones, oxazolidines, imidazolines, and the like. Specific examples of sterically hindered amine light stabilizers include compounds such as, but not limited to, bis (2, 2, 6, 6-tetramethyl-4-piperidyl) sebacate, bis (1, 2, 2, 6, 6-pentamethyl-4-piperidyl) sebacate, 2-me-il-2- (2,2,6,6-tetramethyl-4-piperidyl) amino-N- (2,2 , 6, 6-tetramethyl-4-piperidyl) propionamide, bis (1, 2, 2, 6, 6-pentamethyl-4-piperidyl) -2- (3,5-di-tert-butyl-4-hydroxybenzyl) - 2-n-butylmalonate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, poly [. { 6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazino-2,4-diyl} . { (2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene. { (2,2,6,6-tetramethyl-4-piperidyl) imino} ], poly [(6-morpholino-1, 3, 5-triazino-2,4-diyl). { (2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene. { (2,2,6,6-tetramethyl-4-piperidyl) imino} ], a polycondensed product of dimethyl succinate and 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine, a polycondensate product of N, N-bis (3-aminopropyl) ethylenediamine and 2, 4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine, a polycondensed product of 1, 2, 2,6,6-pentamethyl-piperidinol and 3,9-bis- (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5, 5] undecane with acid 1,2,3 , 4-butanetetracarboxylic acid and bis (l-octoxy-2, 2,6,6,6-tetramethyl-4-piperidyl) sebacate.

Benzofuranone stabilizers include compounds such as, for example, 5,7-di-tert-butyl-3- (3,4-dimethylphenyl) -3H-benzofuran-2-one and the like. The semicarbazide stabilizer includes, for example, 1,6-hexamethylenebis (N, N-dimethylsemicarbazide), 4,4'- (ethylene-p-phenylene) bis (N, N-diethylsemicarbazide), 4,4 '- (methylene) -p-phenylene) bis (N, N-diethylsemicarbazide), 4,4 '- (methylene-p-phenylene) bis (N, N-diisopropylsemicarbazide), a, o, - (p-xylylene) bis (N, N -dimethyl semicarbazide), 1,4-cyclohexylenebis (N, N-dimethylsemicarbazide) and the like. Ultraviolet (UV) stabilizers suitable for the present invention include compounds such as, for example, 2- (3-tert-butyl-2-hydroxy-5-methyl-phenyl) -5-chlorobenzotriazole, 2- (3, 5 -di-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- (2-hydroxy-5-methylphenyl) -benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) -benzotriazole, 2- (3, 5 - di-tere-amyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (a, a-dimethylbenzyl) phenyl] -benzotriazole, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4- methoxybenzophenone, 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, n-hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate, ethyl-2-cyano- 3, 3-diphenylacrylate, 2,4- dihydroxybenzophenone, 2, 2 ', 4, 4-tetrahydroxyabenzophenone, 2- (2-hydrox- 4-octox-phenyl) benzotpazol, 2- [2-hydrox? -3, 5-b] (a, -dimethyl-benzyl) phenyl] -2H-benzotrolzole, 2- (3,5-di-tere-butyl-2-hydroxyphenyl) -5-chlorobenzotpazole, a condensed product of 3 - [methyl 3-tert-butyl-l-5- (2H-benzotpazol-2-yl) -4-hydroxyphenyl] propionate and polyethylene glycol (molecular weight: about 300), a hydroxyphenylbenzotriazole derivative, 2- (4, 6-d? Phen? L-1, 3,5-tpazmo-2-yl) -5-hex? Lox? Phenol and 2- [4,6-b? S (2,4-dimethylphenyl) -1, 3 , 5-tpazmo-2-? L] -5-oct? Lox? Phenol, etc., as well as their mixtures. Some examples of suitable antioxidants that are useful in the present invention include compounds such as n-octadec-l, 3,5-d? -tert-but? L-4-hydrox? H? Droc? Namat ?; tetrakis (3,5-d? -terc-but? l-4-hydrox? 3-n-octadecyl 3, 5-d? - tert -but? L-4-hydroxybenzylphosphonate; 1, 3, 5-tr? S (3, 5-d? -terc-but? L-4-hydroxyl benzyl) isocyanurate; 1,3,5-tpmet? L-2,4,6-tr? S (3,5-d? -terc-but? L-4-hydroxyl benzyl) benzene; bis (3-met? l-5-tert-but? l-4-hydroxy-hydrocmamate) of 3,6-d? oxaoctamethelene; 2,2'-ethylidene-bis (4,6-di-tere-butylphenol); 1, 3, 5-tr? S (2,6-d? Meth? L-4-tert-but? L-3-hydroxyl benzyl) isocyanurate; l, l, 3, -tr? s (2- methyl-4-hydroxy-5-tere-butylphenyl) butane; l, 3,5-tris [2- (3,5-di-tere-butyl-4-hydroxyhydrocinnamoyl-oxy) ethyl] isocyanurate; 3, 5-di- (3, 5-di-tert-butyl-4-hydroxybenzyl) mesitol; 1- (3,5-di-tert-butyl-4-hydroxyanilino) -3,5-di (octylthio) -s-triazine; N, N '-hexamethylene-bis (3,5-di-tert-butyl-hydroxyhydro-cinnamamide); bis [3,3-di (3-tert-butyl-4-hydroxyphenyl) butyrate] ethylene; bis (3,5-di-tert-butyl-4-hydroxyhydrocinnamoyl) hydrazide; N, N-di- (C 2 -C 2 alkyl) -N-methyl-amine oxides; etc. Other suitable compounds to be used as antioxidants herein include alkylated monophenols such as, for example, 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol, 2 , 6-dicyclo-pentyl-4-methylphenol, 2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-di-tert-butyl-4-methoxytriethylphenol, etc .; alkylated hydroquinones such as, for example, 2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butyl-hydroquinone, 2,5-di-tert-amyl-hydroquinone, 2,6- diphenyl-4-octadecyloxyphenol, etc .; alkylated thiodiphenyl ethers such as, for example, 2,2'-thio-bis- (6-tert-butyl-4-methyl-phenol), 2, 2'-thio-bis- (4-octylphenol), 4, 4 '-thio-bis- (6-tert-butyl-2-methyl-phenol), etc .; alkylidene bisphenols such as, for example, 2'-methylene bis- (6-tert-butyl-4-methylphenol), 2, 2'-methylene-bis- (4-methyl-6-cyclohexylphenol), 2,2'-methylene-bis- (6 -nonyl -4 -methyl phenol), 2,2 '-methylene-bis- [6- (a-methylbenzyl) -4-nonylphenol], 2,2'-methylene-bis- [6- (a, a-dimethylbenzyl) -4- nonylphenol], 4, 4'-methylene-bis- (2,6-di-tert-butyl-phenol), 2,6-di- (3-tert-butyl-5-methyl-2-hydroxybenzyl) -4- methylphenol, 1,1,3-tris- (5-tert-butyl-4-hydroxy-2-methylphenyl) butane, di- (3-tert-butyl-4-hydroxy-5-methyl phenyl) dicyclopentadiene, di- [ 2- (3'-tere -butyl-2'-hydroxy-5'-methyl-benzyl) -6-tert-butyl-4-ethylphenyl] -terephthalate, etc .; benzyl compounds such as, for example, 1,3-tri- (3, 5-di-tert-butyl-4-hydroxy-di- (3,5-di-tert-butyl-4-hydroxybenzyl) -sulfide , bis- (4-tert-butyl-3-hydroxy-2, 6-dimethylbenzyl) dithiol terephthalate, etc., acylaminophenols such as, for example, 4-hydroxylauric acid anuide, 4-hydroxy-stearic acid anuide, 2,4-bis-octylmercapto-6- (3, 5-tert-butyl-4-hydroxynyl) -s-triazine, etc .; β- (3, 5-di-tert-butyl-4-) amide. hydroxy-phenyl) propionic such as, for example, N, N'-di- (3, 5-di-tere-butyl-4-hydroxyphenyl-propionyl) hexamethylenediamine, etc., diarylamines such as, for example, diphenylamine, N -phenyl-1-naphthyl-amine, N- (4-tert- octylphenyl) -1-naphthylamine, etc. In accordance with the present invention, one or more pigments and / or dyes, including organic and inorganic compounds, may be present. Suitable inorganic pigments include, for example, oxide pigments such as iron oxides, titanium dioxide, nickel oxides, chromium and cobalt blue oxides and also zinc sulphides, ultramarine, rare earth sulfides, bismuth vanadate and also carbon black, which is considered a pigment for the purposes of this invention. The particular carbon blacks are the acid to alkaline carbon blacks obtained by the gas or furnace process and also the carbon blacks with chemically modified surface, for example carbon blacks containing sulfo or carboxyl. Suitable organic pigments include, for example, those of monoazo, disazo, azo lacquers, β-naphthol, Naphthol AS, benzimidazolone, diazo condensation, azo metal complex, isoindolinone and of the isoindoline series, also polycyclic pigments for example from the phthalocyanine, quinacridone, perylene, perinone, thioindigo, anthraquinone, dioxazine, quinofone and diketopyrrolopyrrole series. Suitable pigments also include solid solutions of the pigments mentioned, mixtures of organic and / or inorganic pigments with organic and / or inorganic pigments such as, for example, metallic pigments, mica or talc coated with carbon black, for example mica CVD coated with iron oxide, and also mixtures between pigments mentioned. Other suitable pigments include lacquered dyes such as Ca, Mg and Al lacquers of dyes containing sulfo and / or carboxyl. Also suitable are pigments from the group of pigments of the azo metal complex or their tautomeric forms which are known. Other suitable pigments include, for example, metallic flake pigments, for example, aluminum, zinc, or magnesium. It is also possible that the metal flake, particularly the aluminum flake, is floating or non-floating. Other suitable additives that may be present according to the invention include surfactant additives such as emulsifiers and foam stabilizers. Examples include N-stearyl-N ', N' -bis-hydroxyethylurea, oleyl polyoxielenamide, stearyl-diethanolamide, isostearyldiethanolamide, polyoxyethylene glycol monooleate, an ester of pentaerythritol / adipic acid / oleic acid, a hydroxyethylimidazole derivative of oleic acid, N - stearylpropylenediamine and the sodium salts of castor oil or fatty acid sulphonates. Alkali metal or ammonium salts of sulfonic acid such as dodecylbenzenesulfonic acid or dinaphthylmethanesulfonic acid and also fatty acids as additive surfactants can also be used. Suitable foam stabilizers include water-soluble polyethersiloxanes. The structure of these compounds is generally such that a copolymer of ethylene oxide and propylene oxide is attached to a polydimethylsiloxane radical. Such foam stabilizers are described, for example, in U.S. Patent No. 2,764,565. In addition to the foam stabilizers and surfactants, other additives that can be used in the molding compositions of the present invention include known blowing agents including nitrogen, cellular regulators, flame retardants, plasticizers, adhesion promoters, fillers. and reinforcing agents such as glass in the form of fibers or flakes or carbon fibers. It is also possible to use the known internal mold releasing agents, such as, for example, stearate of zinc, in the RIM process of the invention. As is known to one of ordinary skill in the art, in the RIM process, an isocyanate, and the active hydrogen-containing compounds are mixed and injected into molds, where the reactants are allowed to react completely. The molded products of the present invention are prepared by reacting the components in a closed mold through the RIM process. The compositions according to the present invention can be molded using conventional transformation techniques at isocyanate rates ranging from about 90 to 120. (preferably from 100 to 110. By the term "index of Isocyanate "(also commonly referred to as NCO index), isocyanate equivalents are defined herein, divided by the total equivalents of substances containing isocyanate-reactive hydrogen, multiplied by 100. In general, in a RIM process, they are mixed intimately two separate streams and subsequently injected into a suitable mold, although it is possible to use more than two streams.The first stream contains the polyisocyanate component, while the second Current contains the isocyanate-reactive components and any other additives that are to be included. The following examples further illustrate details for the preparation and use of the compositions of this invention. The invention, which is shown in the preceding description, will not be limited in its spirit or in its scope by these examples. Those skilled in the art will readily understand that variations in the conditions and procedures of the following preparative procedures can be used to prepare these compositions. Unless otherwise indicated, all temperatures are in degrees Celsius and all parts and percentages are in parts by weight and percentages by weight, respectively.

EXAMPLES The following components were used in the examples of the present application: Isocyanate A: an isophorone diisocyanate trimer having an NCO group content of about 29% and a functionality of about 2.3, prepared by partial trimerization of isophorone diisocyanate in the presence of a N, N, N-trimethylbenzene-methanamine hydroxide catalyst at a trimer to monomer ratio of about 65% by weight to 35% by weight. Polyol A: a polyetherpolyol having a nominal functionality of about 3, a hydroxyl number of about 28, a molecular weight of about 6000, and comprising the reaction product of glycerin with propylene oxide and end-capped with ethylene oxide in presence of a KOH catalyst EG: ethylene glycol Catalyst A: dimethyltin dilaurate catalyst, commercially available as Fomrez UL-28 from GE Silicones Catalyst B: catalyst from 1.8- diazabicyclo (5.4.0) undec-7-ene, commercially available as Polycat DBU from Air Products Surfactant A: a silicone surfactant, commercially available as Niax L-1000 from GE Silicones General Procedure: The components described above were used to produce molded articles by means of reactive injection. The specific substances and the amounts of the substances used are referred to in Table 1 below. The polyurethane forming systems of Examples 1-2 were injected using a MiniRIM cylinder machine. The isocyanate-reactive substances and the different additives were placed in part B of the machine, and the appropriate quantities of the isocyanate component were loaded into part A. The miniRIM was equipped with a Henqecke mq8 mixing head. Part B was preheated to 32.22 ° C (90 ° F) and part A was heated to 32.22 ° C (90 ° F). The substances were injected at an injection pressure of 200 bar and an injection speed of 400 grams / sec. The The substance was injected into a flat plate mold of 3 x 200 x 300 mm heated to about 73.88 ° C (165 ° F). After a period of 60 seconds, the piece was demolded. Physical properties were determined in accordance with ASTM standards. The following ASTM test methods were used in the working examples of the present application.

Table 1: Formulations for Examples 1-2 Table 2: Properties of Examples 1-2 Of the six samples prepared according to the formulation of Table 1 for each of Examples 1 and 2, two of the samples were subjected to physical tests. There was 2-3 replicates of each test for each sample. The results reported in Table 2 represent the average of these for each of Examples 1 and 2. While the invention has been described in detail in the foregoing for illustrative purposes, it should be understood that such detail is solely for this purpose and that those skilled in the art can make variations therein without departing from the spirit and scope of the invention except as may be limited by the claims.

Claims (20)

1. A process for the production of a polyurethane elastomer comprising reacting a reaction mixture by a reactive injection molding technique, wherein the reaction mixture comprises: (A) a polusocyanate component having an NCO group content of about 20. at about 45% by weight, a functionality of about 2.0 to about 2.7, and comprising a polusocyanate (tricylated aliphatic cycle), with the proviso that (i) when the aliphatic polusocyanate (cyclo) is dimecyanate of isophorone, the component (A) contains less than 20% by weight of hexamethylene dusocyanate, and (n) when the aliphatic (cyclo) polusocyanate is trimerized hexamethylene dusocyanate, the component (A) contains less than 10% by weight of isophorone dusocyanate; with (B) an isocyanate-reactive component comprising: (1) from about 70 to about 90% in weight, based on 100% by weight of (B), of one or more polyether polyols having a functionality of about 2 to about 8, a molecular weight of about 1,000 to about 8,000 and lack amine groups; (2) from about 10 to about 30% by weight, based on 100% by weight of (B), of one or more organic compounds having a molecular weight of from about 62 to about 400, having a hydroxyl functionality of 2. to 3, and lack amine groups, in the presence of (C) one or more catalysts corresponding to the formula: where: m: represents an integer from 3 to 8, and n: represents an integer from 3 to 8; and, optionally, (D) one or more additives; where the relative amounts of (A) and (B) are such that the isocyanate index ranges from about 90 to about 120.

2. The method of Claim 1, wherein the polyisocyanate component comprises a prepolymer comprising the reaction product of: (1) at least about 65% to less than 100% by weight, based on 100% by weight of the polyisocyanate component, of the trimerized (cyclo) aliphatic polyisocyanate, and (2) of more than 0% to not more than about 35 % by weight, based on 100% by weight of the polyisocyanate component, of an isocyanate-reactive component having from about 2 to about 6 hydroxyl groups capable of reacting with the NCO groups of (1) and a molecular weight of about 60 to approximately 4,000, wherein the NCO group content of the prepolymer is from about 10% to about 35%.

3. The process of Claim 1, wherein the (cyclo) aliphatic polyisocyanate is selected from the group consisting of l-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane, 4,4'-dicyclohexyl methane diisocyanate and diisocyanate 1, 6-hexamethylene.

4. The process of Claim 2, wherein the (cyclo) aliphatic polyisocyanate is selected from the group consisting of l-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane, 4,4'-dicyclohexyl methane diisocyanate and diisocyanate 1, 6-hexamethylene.

5. The method of Claim 1, wherein (B) (1) has a functionality of 2 to 4 and a molecular weight of 2,000 to 6,000.

6. The method of Claim 1, wherein (B) (2) has a molecular weight of 62 to 90.

7. The method of Claim 2, wherein (A) (2) has a molecular weight of 100 to 400 and a functionality of 2 to 3.

8. The process of Claim 1, wherein (C) further comprises a tin catalyst.

9. The method of Claim 1, wherein (D) said one or more additives comprise one or more stabilizers selected from the group consisting of antioxidants, light stabilizers of sterically hindered amines and ultraviolet stabilizers.

The method of Claim 1, wherein (D) said one or more additives comprise one or more pigments and / or dyes.

11. A polyurethane elastomer comprising the reaction product of: (A) a polyisocyanate component having an NCO group content of about 20 to about 45% by weight, a functionality of from about 2.0 to about 2.7, and comprising a polyisocyanate (tricylated aliphatic cycle), with the proviso that (i) when the (cyclo) aliphatic polyisocyanate is trimerized isophorone diisocyanate, the component (A) contains less than 20% by weight of trimerized hexamethylene diisocyanate, and (ii) when the (cyclo) aliphatic polyisocyanate is trimerized hexamethylene diisocyanate, the component (A) contains less than 10% by weight of isophorone diisocyanate; with (B) an isocyanate-reactive component comprising: (1) from about 70 to about 90% by weight, based on 100% by weight of (B), of one or more polyether polyols having a functionality of about 2 to about 8, a molecular weight of about 1,000 to about 8,000 and lack amine groups; (2) from about 10 to about 30% by weight, based on 100% by weight of (B), of one or more organic compounds having a molecular weight of from about 62 to about 400, having a hydroxyl functionality of 2. to 3, and lack amine groups, in the presence of (C) one or more catalysts corresponding to the formula: where: m: represents an integer from 3 to 8, and n: represents an integer from 3 to 8; and, optionally, (D) one or more additives; where the relative amounts of (A) and (B) are such that the isocyanate index ranges from about 90 to about 120.

12. The elastomer of Claim 11, wherein the polyisocyanate component comprises a prepolymer comprising the reaction product of: (1) at least about 65% to less than 100% by weight, based on 100% by weight of the component polyisocyanate, of the trimerized (cyclo) aliphatic polyisocyanate, and (2) of more than 0% to not more than about 35% by weight, based on 100% by weight of the polyisocyanate component, of an isocyanate-reactive component having from about 2 to about 6 hydroxyl groups capable of reacting with the NCO groups of (1) and a molecular weight of about 60 to about 4,000, wherein the NCO group content of the prepolymer is from about 10% to about 35%.

The elastomer of Claim 11, wherein the (cyclo) aliphatic polyisocyanate is selected from the group consisting of l-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane, 4,4'-dicyclohexyl methane diisocyanate and 1,6-hexamethylene diisocyanate.

14. The elastomer of Claim 12, wherein the (cyclo) aliphatic polyisocyanate is selected from the group consisting of l-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane, 4,4'-dicyclohexyl diisocyanate-methane and 1,6-hexamethylene diisocyanate.

15. The elastomer of Claim 11, wherein (B) (1) has a functionality of 2 to 4 and a molecular weight of 2,000 to 6,000.

16. The elastomer of Claim 11, wherein (B) (2) has a molecular weight of 62 to 90.

17. The elastomer of Claim 12, wherein (A) (2) has a molecular weight of 100 to 400 and a functionality of 2 to 3.

18. The elastomer of Claim 11, wherein (C) further comprises a tin catalyst.

19. The elastomer of Claim 11, wherein (D) said one or more additives comprise one or more stabilizers selected from the group consisting of antioxidants, light stabilizers of sterically hindered amines and ultraviolet stabilizers.

20. The elastomer of Claim 11, wherein (D) said one or more additives comprise one or more pigments and / or dyes.