CA1336350C - Internal mold release agent for use in reaction injection molding - Google Patents

Abstract

The present invention is directed to a mold release, a composition containing the mold release, and a process of using the mold release. The mold release comprises an internal mold release composition comprising (a) a zinc carboxylate containing from 8 to 24 carbon atoms per carboxylate group, and (b) a compatibilizer comprising an amidine group-containing compound of the formula

Description

INTERNAL MOLD R~.TF.A~E AGENT FOR
USE IN REACTION INJECTION MOLDING
BACKGROUND OF THE I~V~:~LlON
Reaction injection molding (RIM) has become an 5 important process for the production of external automotive body parts and other types of molded products. The RIM process involves the intimate mixing of a polyisocyanate component and an isocyanate-reactive component followed by the injection of this mixture into 10 a mold for subsequent rapid curing. The polyisocyanate component is typically based on a liquid polyisocyanate.
The isocyanate-reactive component contains a high molecular weight isocyanate-reactive component, typically a polyol and/or an amine polyether, and 15 usually contains a chain extender containing amino and/or hydroxyl groups. U.S. Patent 4,218,543 describes a RIM process currently being commercially used on a large scale.
While products produced by the RIM process have 20 excellent physical properties, the use of the RIM
process was previously limited by the necessity of using sprayed external mold release agents (e.g., waxes, soaps, and the like). These agents had to be sprayed onto the mold surface before each shot or every several 25 shots. Recently, internal mold release agents have become available which obviate the need for external release agents. Specifically, internal mold release agents containing zinc carboxylates where the carboxylate group contains from 8 to 24 carbon atoms has 30 met with widespread commercial use. Release agents o this type are described in U.S. Patents 4,519,965, 4,581,386 and 4,585,803; and British Patent 2,101,140.
In using such zinc carboxylates it is necessary to mix the carboxylate with a compatibilizer which will solubi-35 lize the zinc carboxylate so that when the resultantMo-3106 ~r mixture is mixed with the isocyanate reactive components, the zinc carboxylate will possess improved resistance to precipitation. British Patent 2,101,140 describes the mixture of a zinc stearate and an 5 epoxidized vegetable oil (such as epoxidized soybean oil).
U.S. Patents 4,519,965 and 4,581,386 describe the use of compatibilizer selected from the group consisting of nitrogen-containing, isocyanate-reactive 10 acylic compounds and nitrogen-containing, isocyanate-reactive polymers. Preferred compatibilizers include polyether polyamines and amine- or hydroxy-terminated, amine-initiated polyethers. U.S. Patent 4,585,803 describes the use of compatibilizers which are tertiary 15 amine compounds which contain at least one tertiary nitrogen. The tertiary amine compounds described advan-tageously contain one or more hydroxy groups. Although the combination of the zinc carboxylates and the compatibilizer noted have met with substantial 20 commercial success, the search continues for other satisfactory compatibilizers.
DESCRIPTION OF THE lNv~NLION
The present invention is directed to a novel internal mold release agent for use in a RIM process, to 25 an isocyanate-reactive component containing the mold release agent, and to the use of the mold release agent in a RIM process.
The internal mold release agent of the present invention comprises:
(a) a zinc carboxylate containing from 8 to 24 carbon atoms per carboxylate group, and (b) a compatibilizer comprising an amidine group-containing compound of the formula Mo-3106 -2-~ 1 336350 R

C
R / \ N-R2 wherein Rl, R2 and R3 are straight or branched, saturated or unsaturated hydrocarbon chains having up to 30 carbon atoms which may be substituted by ether groups, ester groups, amide groups or amidine groups and may also be terminated by isocyanate-reactive groups such as hydroxyl or amino groups, R4 corresponds to the definition of Rl, R2 and R3, but may additionally represent an aromatic substituent having 6 to 15 carbon atoms or may represent the group -NR2R3, with the proviso that when R4 represents the ~roup -NR2R3, Rlcan be hydrogen, and wherein Rl, R2, R3 and R4 may, with one or both of the amidine nitrogens, form a heterocyclic ring, in an amount sufficient to solubilize the zinc carboxylate.
SuitabLe zinc carboxylates which may be used in the internal release agent mixture of the present inven-tion are based on C8-C24, branched or straight chain fatty acids which may be saturated or unsaturated. The carboxylates also include the commercial preparations of a specific carboxylate which also contains impurities or by-products of other fatty acid derivatives. For example, commercial "stearates" may also contain significant quantities of palmitates, myristates, and the like and commercial "tall oil" derivatives normally contain mixtures of stearates, palmitates, oleates, etc.
Examples of specific zinc carboxylates include zinc stearate, zinc oleate, zinc octoate, zinc laurate, zinc ricinoleate and the like.
Mo-3106 -3~

The preferred zinc carboxylates are those which remain soluble in combination with the compatibilizer when in admixture with the high molecular weight isocyanate-reactive component and the chain extender.
The most preferred zinc carboxylate is ~inc stearate, especially those having a high purity such as Zinc Stearate Polymer Grade Type N from Witco, Zinc Stearate RSN 131 HS and IPS from Mallinckrodt and Zinc Stearate Heat Stable Polymer Grade from Nuodex. The zinc carboxylates are used in amounts of about 0.5 to 10~, preferably about 1 to 6% and most preferably about 1 to 4% by weight, based on the weight of the isocyanate-reactive components.
Suitable compatibilizers are those of the type noted which assist in compatibilizing or solubilizing the zinc carboxylates without substantially affecting the processing characteristics of the RIM reaction mixture or the physical properties or paintability of the resultant molded articles. More particularly, the compatibilizers of the present invention comprise an amidine group containing compound of the formula N (I) R ~ C ~ N,-R2 wherein Rl, R2 and R3 are straight or branched, saturated or unsaturated hydrocarbon chains having up to 30, preferably up to 22 carbon atoms which may optionally be substituted by ether groups, ester groups, amide groups or amidine groups and may also optionally be terminated by isocyanate-reactive groups such as hydroxyl or amino groups.
Mo-3106 -4-R4 corresponds to the definition of Rl, R2 and R3, but may additionally represent an aromatic substituent having 6 to 15 carbon atoms or may represent the group -NR2R3, with the proviso that when R4 represents the group -NR2R3, ~lcan be hydrogen, and wherein Rl, R2, R3 and R4 may, with one or both of the amidine nitrogens, form a heterocyclic ring.
Examples of suitable amidine group-containing compounds include diazabicycloundecene, the tetraalkyl guanidines such as tetramethyl guanidine, cyclic amidines of the above formula wherein Rl and R2 form a heterocyclic ring such as compounds corresponding to the formula (I) N

wherein R4 contains a saturated or unsaturated fatty group having 8 to 30, preferably 8 to 22 carbon atoms such as l-heptadec-8-7-enyl and preferably l-heptadecyl and R3 is as defined above. Commercial examples of amidine group containing compounds corresponding to formula I are Monazoline*O available from Mona Industries, wherein R4 is 1-heptadec-8-7-enyl and R3 is hydroxy ethyl; MonazoLine*S available from Mona Industries, wherein R4 is l-heptadecyl and R3 is hydroxy ethyL; Varisoft*~75 available from Sherex Chemical, wherein R4 is a mixture of saturated and unsaturated hydrocarbons and R3 corresponds to the formula * Txa~de~Rrk Mo-3106 -5-.

o wherein R5 corresponds to R4; Monazoline B-219 available from Mona Industries, wherein R4 is l-heptadecyl and R3 corresponds to the formula Monazoline*CY, available from Mona Industries, wherein R3 is hydroxyethyl, and R4 is derived from caprylic acid; Monazoline*T, available from Mona Industries wherein R3 is hydroxyethyl and R4 is derived from tall oil; and Varisoft*3690 imidazoline available from Sherex which is a compound o~ formula (II), wherein R3 is oleylamidoethyl and R4 is oleyl. Also useful are such materials as Polycat*~BU, and Polycat~DBN, both available from Air Products (diazobicyclo-undecene and diazobicyclononane, respectively).
The mold release compositions of the presentinvention are suitable for use with either flexible or rigid, optionally cellular, polyurethane or polyurea elastomers. The molded articles may possess various combinations of these properties such as rigid, non-cellular elastomers or flexible, cellular products for use, e.g., as shoe soles. "Polyurethanes" as defined throughout this application are polyaddition products wherein urethane groups and optionally urea groups are formed during the RIM process according to the invention. "Polyureas~' are defined as polyaddition products wherein only urea groups are formed during the RIM process according to the invention.

* Trade= mark Mo-3106 -6-1 3~63~
-~ The present invention is also directed to an isocyanate-reactive mixture comprising (i) a high molecular weight polymer having at least two isocyanate-reactive groups and having a molecular weight of from 400 to about 10,000, (ii) from about 5 to 50% by weight, based on the weight of component (i) of a chain-extender having at least two isocyanate-reactive groups and (iii) an internal mold release agent mixture comprising:
(a) from about 0.05 to about 10% by weight, based on the weight of components (i) and (ii) of a zinc carboxylate containing from 8 to 24 carbon atoms per carboxylate groups, and (b) a compatibilizer comprising an amidine group-containing compound of the formula ,Rl N
R4-''' ~ N-R2 wherein Rl, R2 and R3 are straight or branched, saturated or unsaturated hydrocarbon chains having up to 30 carbon atoms which may be substituted by ether groups, ester groups, amide groups or amidine groups and may also be terminated by isocyanate-reactive groups such as hydroxyl or amino groups, Mo-3106 -7-R4 corresponds to the definition of ~1~ R2 and R3, but may additionally represent an aromatic substituent having 6 to 15 carbon atoms or may represent the group -NR2R3, with ~& proviso that when R4 represents the 5 group -NR2R3~ Rlcan be hydrogen, and wherein R1, R2, R3 and R4 may, wlth one or both of the amidine nitrogens, form a heterocyclic ring, in an amount sufficient to solubilize the zinc carboxylate so that when component (iii) is in admixture with components (i) and (ii), the 10 zinc carboxylate possesses improved resistance to precipitation. Finally the present invention is directed to a process for the production of optionally cellular parts by reacting a reaction mixture comprising the isocyanate-reactive component which contains the 15 internal mold release with a polyisocyanate, said reaction mixtures being processed by the RIM process at an isocyanate index of from 70 to 130.
Suitable polyisocyanates for use in the present invention are aliphatic, cycloaliphatic, araliphatic, 20 aromatic and heterocyclic polyisocyanates which are known and described for example by W. Siefken in Justus Liebigs Annalen der Ghemie, 562, pages 75-136. Specific examples include ethylene diisocyanate, 1,4-tetra-~ethylene diisocyanate, 1,6-hexamethylene diisocyanate, 25 1,12-dodecane diisocyanate, cyclobutane- 1,3-diiso-cyanate, cyclohexane-1,3- and -1,4-diisocyanate and mixtures thereof, l-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (isophorone diisocyanate or IPDI), 2,4- and 2,6-hexahydrotoluylene diisocyanate and 30 mixtures thereof, hexahydro-1,3- and/or -1,4-phenylene dlisocyanate, perhydro-2,4'- and/or -4,4'-diphenyl methane diisocyanate, 1,3- and 1,4-phenylene diisocyanate, 2,4- and 2,6-toluylene diisocyanate and mixtures thereof, diphenyl methane 2,4'- and/or 35 4,4'-diisocyanate, naphthylene 1,5-diisocyanate, triphenyl methane-4,4',4"-triisocyanate and polyphenyl Mo-3106 -8-.. ..

polymethylene polyisocyanates of the type ob~ained by condensing aniline with formaldehyde, followed by condensation.
It is preferred to use the readily available 5 polyisocyanates such as 2,4- and 2,6-toluene diisocyanate and mixtures of these isomers, polyphenyl polymethylene polyisocyanates of the type obtained by condensing aniline with formaldehyde, followed by phosgenation, and polyisocyanates containing 10 carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret groups. Particularly preferred are the liquid derivatives of 4,4'-diphenyl methane diisocyanate (MDI) which may be liquefied inter alia by introducing 15 carbodiimide groups, blending with 2,4l-diphenyl methane diisocyanate or by introducing urethane groups.
Especially preferred are the liquefied derivatives of MDI prepared by reacting MDI with 0.1 to 0.3 mols of a polypropylene glycol having a molecular weight of up to 20 about 700, in particular, dipropylene glycol, tripropylene glycol or mixtures thereof as disclosed, for example, in U.S. Patent 3,644,457.
Also suitable for use as the polyisocyanate component are isocyanate-terminated prepolymers based on 25 the above-mentioned polyisocyanates and the isocyanate-reactive compounds, preferably hydroxyl compounds, disclosed hereinafter for use in accordance with the present invention. Prepolymers of this type are disclosed in U.S. Patent 4,374,210. The prepolymers are 30 preferably based on the polyether or polyester polyols disclosed hereinafter and, optionally, the low molecular weight, hydroxyl group-containing chain extenders which are also disclosed hereinafter. Blends of any of the previously disclosed polyisocyanates may also be used in 35 accordance with the present invention.

Mo-3106 -9-1 3~63~
~ Other suitable reactants for preparing the products of the present invention include compounds containing at least two isocyanate-reactive groups.
These compounds may be divided into two groups, high 5 molecular weight compounds having a molecular weight of 400 to about 10,000 and low molecular weight compounds, i.e, chain extenders, having a molecular weight of 62 to 399. Examples of suitable high molecular weight compounds include the polyesters, polyethers, polythio-10 ethers, polyacetals and polycarbonates containing atleast 2, preferably 2 to 8 and most preferably 2 to 4 isocyanate-reactive groups of the type known for the production of polyurethanes.
The high molecular weight polyethers suitable 15 for use in accordance with the invention are known and may be obtained, for example, by polymerizing epoxides such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin in the presence of BF3 or by chemically adding these epoxides, 20 preferably ethylene oxide and propylene oxide, in admixture or successively to components containing reactive hydrogen atoms such as water, alcohols or amines. Examples of alcohols and amines include the low molecular weight chain extenders set forth hereinafter, 25 4,4'-dihydroxy diphenyl propane, sucrose, aniline, ammonia, ethanolamine and ethylene diamine. It is preferred to use polyethers which contain substantial amounts of primary hydroxyl groups in terminal positions (up to 90% by weight, based on all of the terminal 30 hydroxyl groups present in the polyether). Polyethers modified by vinyl polymers, of the type formed, for example, by polymerizing styrene or acrylonitrile in the presence of polyether (U.S. Patents 3,383,351;
3,304,273; 3,523,093; and 3,110,695; and German Patent 35 1,152,536), are also suitable, as are polybutadienes containing OH groups.
Mo-3106 -10-~ 1 336350 In additlon, polyether polyols which contain high molecular weight polyadducts or polycondensates in finely dispersed form or in solution may be used. Such modified polyether polyols are obtained when poly-5 addition reactions (e.g. reac~ions between poly-isocyanates and amino functional compounds) or polycon-densation reactions (e.g., between formaldehyde and phenols and/or amines) are directly carried out in situ in the polyether polyols.
Suitable examples of high molecular weight polyesters include the reaction products of polyhydric, preferably dihydric alcohols (optionally in the presence o~ trihydric alcohols), with polyvalent, preferably ~ divalent, carboxylic acids. Instead of using the free 15 carboxylic acids, it is also possible to use the corre-sponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures ~hereof for producing the polyesters. The polycar-boxylic acids may be aliphatic, cycloaliphatic, 20 aromatic, and/or heterocyclic and may be unsaturated or substituted, for ex~mple, by halogen atoms. The poly-carboxylic acids and polyols used to prepare the polyesters are known and described for example in U.S.
Patents 4,098,731 and 3,726,952. Suitable polythioethers, 25 polyacetals, polycarbonates and other polyhydroxyl compounds are also disclosed in the above identified U.S. patents. Finally, representatives of the many and varied compounds which may be used in accordance with the invention may be found for example in High Polymers, 30 Volume XVI, "Polyurethanes, Che~istry 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 198-19g; and in Kunststoff-Handbuch, Vol. VII, Vieweg-Hochtlen, Carl Hanser Verlag, 35 Munich, 1966, pages 45-71.
Mo-3106 -11-Suitable aminopolyethers which may be used in accordance with the present invention as high molecular weight compounds (the molecular weight is always the average molecular weight which may be calculated from 5 the functionality and the content of isocyanate-reactive groups) are those wherein at least about 30 and preferably about 60 to 100 equivalent ~ of the isocyanate-reactive groups are primary and/or secondary (preferably primary) aromatically or aliphatically 10 (preferably aromatically) bound amino groups and the remainder are primary and/or secondary aliphatically bound hydroxyl groups.
In these compounds, the terminal residues carrying the amino groups may also be attached to the 15 polyether chain by urethane or ester groups. These "aminopolyethers" are prepared by methods known per se.
For example, polyhydroxypolyethers such as polypropylene glycol ethers may be aminated by reaction with ammonia in the presence of Raney nickel and hydrogen (BE-PS
20 634,741). US-PS 3,654,370 describes the production of polyoxyalkylene polyamines by reaction of the corre-sponding polyol with ammonia and hydrogen in the presence of a nickel, copper, chromium catalyst. DE-PS
1,193,671 describes the production of polyethers 25 containing terminal amino groups by hydrogenation of cyanoethylated polyoxypropylene ethers. Other methods for the production of polyoxyalkylene (polyether) amines are described in US-PS 3,155,728, US-PS 3,236,895 and FR-PS 1,551,605. The production of polyethers 30 containing terminal secondary amino groups is described, for example, in FR-PS 1,466,708.
Polyhydroxypolyethers of relatively high molecular weight may be converted into the corresponding anthranilic acid esters by reaction with isatoic acid 35 anhydride, as described, for example, in DE-OS Nos.

2,019,432 and 2,619,840 and in US-PS Nos. 3,808,250, Mo-3106 -12-~ 1 336350 3,975,428 and 4,016,143. Polyethers cont~lning terminal aromatic amino groups are formed in this way.
Accordlng ~o DE-OS 2,546,536 and US-PS
3,865,791, relatively high molecular weight compounds 5 containing terminal amino groups are o~tained by reaction of NCO prepolymers based on polyhydroxypoly-ethers with enamines, aldimines or ketimines containing hydroxyl groups and subsequent hydrolysis.
It is preferred to use amino polyethers 10 obtained Sy hydrolysis of compounds containing terminal isocyanate groups, or example in accordance with DE-OS
2,948,419 or U.S. Patent 4,515,923. In this process, poly-ethers most preferably containlng 2 to 4 hydroxyl groups L.. are reacted with polyisocyanates to form NCO prepolymers 15 and, in a second step, the isocyanate groups are converted by hydrolysis into amino groups.
The "aminopolyethers" used in accordance with the invention are often mixtures of the compounds mentioned by way of example and (on a statistical 20 average) most preferably contain 2 to 4 terminal isocyanate-reactive groups. In the process according to the invention, the "aminopolyethers" may be used in a~mixture with polyhydroxypolyethers free from amino groups.
In accordance with the present invention, the hlgh molecular weight compounds are used in ad~ixture with up to about 952 by weight, preferably up to about 5G~ by weight, more preferably about 8 to 30~ by weight and most preferably about 12 to 26~ by weight, based on 30 the total ~uantity of the high molecul~r weight compound~, of the low molecular weight chain extenders.
Examples of suitable hydroxyl group-contalning chain extenders include ethylene glycol, 1,2- and 1,3-propane diol, 1,3- and 1,4- and 2,3-butane diol, 1,6-hexane 35 diol, 1,10-decane diol, diethylene glycol, triethylene Mo-3106 -13-A

~ 336350 glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, glycerol and trimethylol propane.
Other suitable chain extenders include aromatic polyamines, preferably diamines, having molecular 5 weights of less than 400, especially the sterically hindered aromatic polyamines, preferably diamines, having molecular weights of less than 400, especially the sterically hindered aromatic diamines which contain at least one linear or branched alkyl substituent in the 10 ortho-position to the first amino group and at least one, preferably two linear or branched alkyl substituents containing from 1 to 4, preferably 1 to 3, carbon atoms in the ortho-position to a second amino group. These aromatic diamines include l-methyl-3,5-15 diethyl-2,4-diamino benzene, 1-methyl-3,5-diethyl-2,6-diamino benzene, 1,3,5-trimethyl-2,4-diamino benzene, 1,3,5-triethyl-2,4-diamino benzene, 3,5,3',5'-tetra-ethyl-4,4'-diamino diphenylmethane, 3,5,3',5'-tetra-isopropyl-4,4'-diamino diphenylmethane, 3,5-diethyl-20 3',5'-diisopropyl-4,4'-diamino diphenylmethane, 3,5-diethyl-5,5'-diisopropyl-4,4'-diamino diphenyl-methane, l-methyl-2,6-diamino-3-isopropylbenzene and mixtures of the above diamines. Most preferred are mixtures of l-methyl-3,5-diethyl-2,4-diamino benzene and 25 1-methyl-3,5-diethyl-2,6-diamino benzene in a weight ratio between about 50:50 to 85:15, preferably about 65:35 to 80:20.
In addition, aromatic polyamines may be used in admixture with the sterically hindered chain extenders 30 and include, for example, 2,4- and 2,6-diamino toluene, 2,4'- and/or 4,4'-diamino diphenylmethane, 1,2- and 1,4-phenylene diamine, naphthalene-1,5-diamine and triphenylmethane-4,4',4"-triamine. The difunctional and polyfunctional aromatic amine compounds may also 35 exclusively or partly contain secondary amino groups such as,4,4'-di-(methylamino)-diphenylmethane or Mo-3106 -14-l-methyl-2-methylamino-4-amino-benzene. Liquid mixtures of polyphenyl polymethylene-polyamines, of the type obtained by condensing aniline with formaldehyde, are also suitable. Generally, the nonsterically hindered 5 aromatic diamines and polyamines are too reactive to provide sufficient processing time in a RIM system.
Accordingly, these diamines and polyamines should generally be used in combination with one or more of the previously mentioned sterically hindered diamines or 10 hydroxyl group-containing chain extenders.
Other additives which may be used in the present invention include catalysts, especially tin(II) salts of carboxylic acids, dialkyl tin salts of carboxylic acids, dialkyl tin mercaptides, dialkyl tin 15 dithioesters and tertiary amines. Preferred among these catalysts are dibutyl tin dilaurate and 1,4-diaza-bicyclo-(2,2,2)-octane (triethylene diamine), especially mixtures of these catalysts. The catalysts are generally used in amounts of about 0.01 to 10~, 20 preferably about 0.05 to 2~, based on the weight of the high molecular weight component.
It is also possible to use surface-active additives such as emulsifiers and foam stabilizers.
Examples include N-stearyl-N',N'-bis-hydroxyethyl urea, 25 oleyl polyoxyethylene amide, stearyl diethanol amide, isostearyl diethanolamide, polyoxyethylene glycol monoleate, a pentaerythritol/adipic acid/oleic acid ester, a hydroxy ethyl imidazole derivative of oleic acid, N-stearyl propylene diamine and the sodium salts 30 of castor oil sulfonates or of fatty acids. Alkali metal or ammonium salts of sulfonic acid such as dodecyl benzene sulfonic acid or dinaphthyl methane sulfonic acid and also fatty acids may also be used as surface-active additives.
Suitable foam stabilizers include water-soluble polyether siloxanes. The structure of these compounds Mo-3106 -15-r ~ 3i 3 ~ 3 ~i ~
-~ is generally such that a copolymer of ethylene oxide and propylene oxide is attached to a polydimethyl siloxane radical. Such foam stabilizers are described in U.S.
Patent 2,764,565. In addition to the catalysts and 5 surface-active agents, other additives which may be used in the molding compositions of the present invention include known blowing agents, cell regulators, flame retarding agents, plasticizers, dyes, fillers and reinforcing agents such as glass in the form of fibers 10 or flakes or carbon fibers.
The compositions according to the present invention may be molded using conventional processing techniques and are especially suited for processing by the RIM process. In general, two separate streams are 15 intimately mixed and subsequently injected into a suitable mold, although it is possible to use more than two streams. The first stream contains the polyiso-cyanate component, while the second stream contains the polyol component, chain extender, the internal mold 20 release agent mixture and any other additive which is to be included.
The invention is further illustrated but is not intended to be limited by the following examples in which all parts and percentages are by weight unless 25 otherwise specified.

Mo-3106 -16-EXAMPLES
Example 1 The amidine used was Monazoline*CY, available from Mona Industries, and having the structure:

N- CH
It 1 2 \ /
N

where R3 is hydroxyethyl and R4 is derived from caprylic acid. In each case, 2 parts of the zinc carboxylic were dissolved in 4 parts of the amidine. In each instance, the mixtures were heated at a rate of 1C per minute until dissolution began. The mixtures were then held at that temperature until dissolution was complete. Zinc oleate and zinc stearate yielded clear liquids, while zinc laurate yielded a cloudy liquid.
Example 2 2 parts each of zinc oleate, zinc laurate and zinc stearate were dissolved in 4 parts of Polycat DBU
using the identical technique of Example 1. Clear liquids were obtained in the case of zinc oleate and zinc stearate, while a cloudy liquid was obtained in the case of zinc laurate. Polycat*DBU is available from Air Products, and has the structure:

J

~ * Trade-mark Mo-3106 -17-5 ~
Example 3 2 parts of zinc oleate, zinc laurate and zinc stearate were dissolved in 4 parts of Polycat DBN using the exact technique of Example 1. A clear liquid was 5 obtained in the case of zinc oleate, a cloudy liquid was obtained in the case of zinc stearate and the components separated in the case of zinc laurate. Polycat DBN is available from Air Products, and has the following structure:

/~~
~ ~ N J

Example 4 2 parts each of zinc oleate, zinc laurate and zinc stearate were dissolved in 4 parts of Sherex's Varisoft 3690 imidazoLine using the exact technique of 15 Example 1. In the case of zinc oleate, a clear liquid resulted, while in the case of zinc laurate and zinc stearate, a solid resulted. Varisoft*3690 imidazoline is of the structure:

\ /
N

where R3 is oleylamido ethyl, and R4 is oleyl.
* Trade-mark Mo-3106 -18-Example 5 2 parts each of zinc oleate, zinc laurate and zinc stearate were dissolved in 4 parts of Monazoline*0 from Mona Industries using the exact technique of Example 1. In the case of zinc oleate, a clear liquid resulted. In the case of zinc laurate, a cloudy viscous liquid resulted, while in the case of zinc stearate, a solid resulted. Monazoline 0 is of the structure:

N - CH
~t 1 2 \ /
N

where R3 is hydroxy ethyl and R4 is l-heptodecyl.
Example 6 2 parts each of zinc oleate, zinc laurate and zinc stearate were dissolved in 4 parts of tetramethyl guanidine using the exact technique of Example 1. Clear liquids resulted in the cases of zinc oleate and zinc stearate, while a separated liquid resulted with zinc laurate.
Example 7 2 parts each of zinc oleate, zinc laurate and zinc stearate were dissolved in 4 parts of Monazolin~*T
using the exact technique of Example 1. There was slight separation of components in the case of zinc oleate. A cloudy liquid resulted in the case of zinc laurate, a solid resulted in the case of zinc stearate.
RIM Examples 8-14 Zinc laurate solubilized by Monazoline*:0 was tested in several RIM systems. In the RIM examples, the following materials were used:
* Trade-mark Mo-3106 -19-, a) POLYOL: An ethylene oxide-tipped, glycerine-initiated, propylene oxide/ethylene oxide polyether (weight ratio of propylene oxide to ethylene oxide of about 7:1) having an OH number of about 28.
b) DETDA: An 80/20 mixture of 1-methyl-3,5-diethyl-2,4- and -2,6-diamino benzene.
c) SOLUBILIZER A: An ethylene diamine/-propylene oxide adduct having an OH number of about 630.
d) SOLUBILIZER B: An amine terminated 10 polyether having a molecular weight of about 400, containing three primary amino groups, and available from Texaco as Jeffamine T-403.
e) DBTDL: Dibutyltin dilaurate.
f) TEDA: Triethylenediamine g) ISO: A tripropylene glycol/4,4'-methylene bis(phenylisocyanate) adduct having an NCO content of about 23X.
See Table I. Examples 8 and 9 were comparative examples, while Examples 10 through 14, which use 20 Monazoline O, fall under the present invention. These systems show much higher elongation, notched Izod impact and tear strength. In addition, tin and amine catalysts were not needed for good green strength (System F). All systems showed good release and green strength.
RIM plaques were prepared using an LK-06 laboratory RIM machine. A rectangular mold, 300 mm x 200 mm x 8 mm, was used to mold the samples under the following conditions:
Component A Temperature 32C
Component B Temperature 40C
Isocyanate Index 110 A/B Weight Ratio (125-140)/100 Mold Temperature 60C
Impingement Pressure2646 PSI
External Mold ReleaseCHEM-TREND

* Trade-mark Mo-3106 -20-Demolding Time 2 minutes Postcure Conditions 120C for 1 hour The external release agent was only applied to the mold prior to the production of the first sample. The 5 samples were tested for density (ASTM D-792), flex modulus (ASTM D-790), elongation (ASTM D-638), heat sag (ASTM D-3769), tear strength-die "C" (ASTM D-624) and notched Izod (ASTM D-256).
The results and formulations (in parts by 10 weight) were as set forth in Table I.

Mo-3106 -21-o ~ U~ U~
~D O I I ~ e~ I I ~ a~
U~ ~ ~

,_ o o ~ oo o I , c~

o~ ~ ~C~ C~ o ~ CO oo o a~ o I I c~ ~ o ~ ~ c~ oo oo ~ ~ ,_ ~ o ~ o o ~o H

O o o o U~

ao ~ _I o 1~ o ~ 1-- o ~o I~ æ~ O~D

U~
CO O O l--.. . . . O
00 ~ O ~ I I C~ ~ ~ ~ ~ O
~ ~ U~

0 1 C~
t F

~8 o ~ ` C
¢ ~ ~ O
O 1:~ C C ~ ~rl Y~ ~ I cn ~ ~ N
p.~ ~ U. C ' ;~: ~1 ~ ~ ¢ H

Mo- 3106 - 22-Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and ~hat variations can be made therein by 5 those skilled in the art without depar~ing from the spirit and scope of the invention egcept as it may be limited by the claims.

Mo-3106 -23-

Claims (8)

1. An internal mold release composition comprising (a) a zinc carboxylate containing from 8 to 24 carbon atoms per carboxylate group, and (b) a compatibilizer comprising an amidine group-containing compound of the formula wherein R1, R2 and R3 are straight or branched, saturated or unsaturated hydrocarbon chains having up to 30 carbon atoms which may be substituted by ether groups, ester groups, amide groups or amidine groups and may also be terminated by isocyanate-reactive groups wherein R4 corresponds to the definition of R1, R2 and R3, but may additionally represent an aromatic substituent having 6 to 15 carbon atoms or may represent the group -NR2R3, with the proviso that when R4 represents the group -NR2R3, R1 can be hydrogen, and wherein R1, R2, R3 and R4 may, with one or both of the amidine nitrogens, form a heterocyclic ring, in an amount sufficient to solubilize the zinc carboxylate.

2. The composition of Claim 1 wherein component (a) is zinc stearate.

3. The composition of Claim 1 wherein said isocyanate-reactive groups are hydroxyl groups or amino groups.

4. An isocyanate-reactive composition comprising (i) a high molecular weight polymer having at least two isocyanate-reactive groups and having a molecular weight of from 400 to about 10,000, (ii) from about 5 to about 50% by weight, based on the weight of component (i) of a chain extender having at least two isocyanate-reactive groups, and (iii) an internal mold release composition comprising (a) a zinc carboxylate containing from 8 to 24 carbon atoms per carboxylate group, and (b) a compatibilizer comprising an amidine group-containing compound of the formula wherein R1, R2 and R3 are straight or branched, saturated or unsaturated hydrocarbon chains having up to 30 carbon atoms which may be substituted by ether groups, ester groups, amide groups or amidine groups and may also be terminated by isocyanate-reactive groups wherein R4 corresponds to the definition of R1, R2 and R3, but may additionally represent an aromatic substituent having 6 to 15 carbon atoms or may represent the group -NR2R3, with the proviso that when R4 represents the group -NR2R3, R1 can be hydrogen, and wherein R1, R2, R3 and R4 may, with one or both of amidine nitrogens, form a heterocyclic ring, in an amount sufficient to solubilize the zinc carboxylate.

5. The composition of Claim 4 wherein component (iii) (a) is a zinc stearate.

6. The composition of Claim 4 wherein said isocyanate-reactive groups are hydroxyl groups or amino groups.

7. A process for the preparation of a molded part comprising introducing a reaction mixture into a closed mold via the RIM process, wherein the reaction mixture comprises an organic isocyanate, at least one active hydrogen containing material, and an internal mold release composition comprising (a) a zinc carboxylate containing from 8 to 24 carbon atoms per carboxylate group, and (b) a compatibilizer comprising an amidine group-containing compound of the formula wherein R1, R2 and R3 are straight or branched, saturated or unsaturated hydrocarbon chains having up to 30 carbon atoms which may be substituted by ether groups, ester groups, amide groups or amidine groups and may also be terminated by isocyanate-reactive groups wherein R4 corresponds to the definition of R1, R2 and R3, but may additionally represent an aromatic substituent having 6 to 15 carbon atoms or may represent the group -NR2R3, with the proviso that when R4 represents the group -NR2R3, R1 can be hydrogen, and wherein R1, R2, R3 and R4 may, with one or both of the amidine nitrogens, form a heterocyclic ring, in an amount sufficient to solubilize the zinc carboxylate.

8. The process of Claim 7 wherein said isocyanate-reactive groups are hydroxyl groups or amino groups.