CA1115900A

CA1115900A - Process for the production of cold setting foams which contain urethane groups

Info

Publication number: CA1115900A
Application number: CA289,078A
Authority: CA
Inventors: Jurgen Ick; Hans J. Meiners; Gunter Oertel; Gunter Hauptmann; Klaus Konig
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1976-10-21
Filing date: 1977-10-17
Publication date: 1982-01-05
Also published as: MX145634A; FR2368506A1; IT1090532B; AU505253B2; JPS58458B2; NL186171C; SE460793B; AT369759B; SE7711820L; DE2647482A1; GB1585901A; ES463396A1; CH636364A5; BR7707032A; NL186171B; JPS5351299A; BE859937A; FR2368506B1; NL7711432A; AU2993477A

Abstract

Mo-1780-JG
LeA 17,468 LeA 17,964 PROCESS FOR THE PRODUCTION OF COLD SETTING
FOAMS WHICH CONTAIN URETHANE GROUPS

ABSTRACT OF THE DISCLOSURE

The instant invention is directed to a process for the production of cold setting, flexible foams which contain urethane groups by the reaction of polyethers with a molecular weight of 400 to 10,000 which contain at least two hydroxyl groups and in which at least 10% by weight of the hydroxyl groups are primary hydroxyl groups, with a mixture of diphenyl methane diisocyanates and oligomeric polyphenyl-polymethylene polyisocyanates in the presence of blowing agents and optionally in the presence of catalysts and other foaming aids, the improvement wherein the mixture of diphenylmethane diisocyanates and polyphenyl-polymethylene polyisocyanate mixtures contains from 60 to 90% by weight of 4,4'-diphenylmethane diisocyanate and from 3 to 30% by weight of 2,4'-diphenylmethane diisocyanate.

LeA 17,468

Description

591:~

.

PROCESS FOR THE PRODUGTION OF CGLD SETTING
FOAMS WHIC~ CONTAIN URETh NE GROUPS_ BACKGROU~D OF THE INVENTION

Foams which contain urethane groups are widely used, for ~xample, in the field of insulation for the manufacture of structural elements and for upholstery I ~
: purposes. It is known that cold set-ting foams which con-tain urethane groups can be produced from higher molecular welght polyols such as hydroxyl polyethers, special poly-isocyanates, water and/or other blowing agents, : optionally in the presence of catalysts and other auxiliary agents. The higher molecular weight polyols ~ used are frequently polyethers, for example, having .~ 15 molecular weights of 400 - 10,000, which contain at least two hydroxyl groups and in which at least about 10~ of '~'' ~
LeA 17~468 ~

S~

the hydroxyl groups are primary hydroxyl groupsO These polyethers are used, for example, in combination with special polyisocyanates. The special isocyanates used may be, for example, a mixture of diphenylmethane diisocyanates and polyphenyl-polymethylene polyisocyanates.
The previously known cold setting foams based on polyphenyl-polymethylene polyisocyanates, for example, those described in German Offenlegungsschrift 2J425/657~ (see particularly Examples 1-5) have a serious disadvantage, which 10 is particularly disturbing when the foams are produced inside molds. Thus, even when the reaction mixture has been inside the mold for abou~ 10 minutes, the foams formed during this time are still irreversibly deformable. Although this tendency to deformation can be overcome by storage of the reaction 15 mixture for about 24 h~urs or by subsequent heating of the foams after their removal from the mold, for about thirty minutes at 120C, it is always a disadvantageous characteristic.
Furthermore, molding times of less than five minutes cannot generally be achieved.
An improved process for the production of cold setting, flexible foams which contain urethane groups has now been found. This process reduces or substantially obviates the disadvantages described above and is based on the use of a certain mixture of diphenylmethane diisocyanates and oligomer ~5 polyphenyl-polymethylene polyisocyanates.
DESCRIPTION OF THE INVENTION
The present invention thus relates to a process for the production of molded cold setting, flexible foams, having a cellular structure on the sur'ace thereof, and the LeA 17,468 -2-B

55~

foams produced thereby, which foams contain urethane groups by the reaction in a mold of polyethers with amolecular weight of 400 to 10,000 which contains at least two hydroxyl groups and in which at least 10% by weight of the hydroxyl groups are primary hydroxyl groups, mixed with a mixture of diphenyl-methane diisocyanates and oligomeric polyphenyl-polymethylene polyisocyanates in the presence of blowing agents and in the presence of one or more amine catalysts and optionally other catalysts and foaming aids, characterized in that the mixture 10 of diphenylmethane diisocyanates and polyphenyl-polymethylene polyisocyanates, which is substantially free of carbodiimide groups and contains from 60 to 90% by weight, preferably 65-80% by weight of 4,4'-diphenylmethane diisocyanate and from 3 to 30% by weight, preferably 10~30% by weight of 2,4'-diphenyl-15 methane diisocyanate and wherein the reaction is carried outin the absence of foam stabilizers and wherein the amine catalysts are selected from the group consisting of diaza-bicyclo-2,2,2-octane, 2,2'-dimethyl-aminodiethyl ether, tetra-methyl ethylene diamine, and N-methyl morpholine. The amount 20 of polyphenyl-polymethylene polyisocyanates in this isocyanate mixture is from 0-37% by weight, preferably from 10-20% by weight.
The invention has surprisingly been found to show the following practical advantages:
(1) Due to the very rapid hardening of these foam systems, molding times of between 3 minutes and less than 1 minute can be obtained.

(2) The rapid hardening substantially reduces the tendency of the foam to deformation, so that any intermediate 30 storage time can be considerably reduced. Reheating of the molded articles after removal from the mold is no longer necessary. The foams can be packaged a-fter 10 minutes without risk of defo~mation.
LeA 17,468 -3-~59~

The polyisocyanate mixture itself is known in the art. In addition to the polyisocyanate mixture used accord-ing to the invention, other isocyanates may be used as starting materials in quantities of up to 20~ by weight, based on the quantity of polyisocyanate mixture according to the invention. These additional, optional, isocyanates include aliphatic, cycloaliphatic and other aromatic and heterocyclic polyisocyanates such as those described, for example, by W. Siefken in Jus~us Liebigs Annalen der Chemie 562, pages 75 to 136. Specific examples include ethylene diisocyanate; 1,4-tetramethylene diisocyanate; 1,6-hexa-methylene diisocyanate; 1,12-dodecane di}socyanate;
cyclobutane-1,3-diisocyanate; cyclohexane 1,3- and 1,4-: diisocyanate and mixtures of these isomers; l-isocyanato-

3,3,5-trimethyl-5-isocyanatomethy~-cyclohexane as described in German Auslegeschrift 1,202,785 and U. S. Patent ; ~ : 3,401,190; 2,4- and 2,6-hexahydrotolylene diisocyanate arld mixtures of these isomers; hexahydro-1,3- and/or -1,4-phenylene diisocyanate; perhydro-2,4'- and/or -4,4'-diphenylmethane diiæocyanate; 1,3- and 1,4-phenylene diisocyanate; 2,4 and 2,6-tolyene diisocyanate and mixtures of these isomers naphthylene-1,5-diisocyanate; triphenyl-methane-4,4',4"-triisocyanate; m- and p-isocyanatophenyl-~
sulphonyl isocyanate as described in U. S. Patent 3,454,606;
perchlorinated aryl polyisocyanates as described, for example, in German Auslegeschrift 1,157,601 and U. S. Patent 3,277,138; polyisocyanates having carbodiimide groups as de~cribed in German Patent 1,092,007 and U. S. Patent 3,152,162l the diisocyanates described in U. S. Patent : LeA 17,468 -4_ 3,492,330; polyisocyanates having allophanate groups as described, e.g., in British Patent 994,890; Belgian Patent 761,626 and published Dutch Patent Application 7,102,524;
polyisocyanates having isocyanurate groups as described, for example, in U. S. Patent 3,001,973, German Patents 1,022,789, 1,222,067 and 1,027,394, and in German Offenlegungsschriften 1,929,034 and 2,004,048; polyisocyanates having urethane groups, e.g., as described in Belgian Patent 752,261 and in U. S. Patent 3,394,164; polyisocyanates having acylated urea groups, as described in German Patent 1,230,778; polyisocyan-ates having biuret groups, e.g., as described in ~erman Patent 1,101,394, U. S. Patents 3,124,605 and 3,201,372, and in British Patent 889,050; polyisocyanates prepared by te~omerization reactions, as described, for example, in U. S.
Patent 3,654,106; polyisocyanates with ester groups, e.g , such as those described in British Patents 965,474 and 1,072,956, U. S. Patent 3,567,763 and German Patent 1,231,688, reacti.on products of the above-mentioned isocyanates with acetals, as described in German Patent 1,072,385; and poly-isocyanates containing polymeric fatty acid groups, as described in U. S. Patent Specification 3,455,883.

~ The distillation residues obtained from the commercial production of isocyanates and still containing isocyanate groups may also be used, if desired as solutions in one or more o~ the above-mentioned polyisocyanates. Any mixtures of the above-mentioned polyisocyanates may, of course, be used.

LeA 1~1,468 -5_ r~

Monofunctional isocyanates, such as propyl iso_yan-ate, cyclohexyl isocyanate, phenyl isocyanate, tolyl isocyanate and p-chlorophenyl isocyanate may also be inc:Luded.

Polyethers containing at least two hydroxyl groups and generally having a molecular weight of from 400 to 10,000 are also used as a starting component according to the inven-tion. Particularly preferred polyethers containing from 2 - 8, preferably 2 - 4 hydroxyl groups and especially those with a molecular weight of from 800 to 10,000, and most preferably 1,000 to 6,000. At least 10%, by weight, of the nydroxyl groups in these polyethers are primary hydroxyl groups.

These polyethers are known in the art and may be prepared, for example, by the polymerization of epoxides, such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin, alone, e.g., in the presence of boron trifluoride, or by addition of these epoxides, either as mixtures or successively, to start-ing components with reactive hydrogen atoms. Suitable start-ing components include water, alcohols, ammonia:or amines.
Suitable examples include ethylene glycol; propylene glycol-(1,3) or -(1,2); trimethylolpropane; glycerol, 4,~'-dihydroxy-diphenylpropane; anniline; ethanolamine; ethylenediamine;
and the like. In these polyethers, the pr.imary hydroxyl ~end) groups are preferably formed by the reaction of ethylene oxide.
Sucrose polyethers may also be used according to the inven-tion, for example, those described in German Auslegeschriften 1,176,358 and 1,064,938. Polyethers modified by vinyl : LeA 17,468 t - 6-:; ~ ,.

9/~

polymers, for example, the compounds obtained by the poly-merization of styrene and acrylonitrile in the presence of polyethers, as described in U. S. Patents 3,383,351; 3,3~4,273;
3,523,093 and 3,110,695 and German Patent 1,152,536 and polybutadienes which contain hydroxyl groups are also suitable.

The starting components which may be used according to the invention in addition to -the polyethers may al50 include in quantities of up to 50~, by weight, based on the polyethers, hydroxyl polyesters, hydroxyl polyethers which are substantially free from primary hydroxyl grou~s, hydroxyl polythioethers, hydroxyl polyacetals, hydroxyl polycarbonates and hydroxyl polyester amides, all of which are known in the art for the production of both homoqeneous and cellular poly-urethanes. These hydroxyl polymers contain at least two hydroxyl groups, generally 2 to 8, preferably 2 to 4 hydroxyl groups and they generally have molecular weights of from 400 to 10,000, pre~erably 800 to 10,000 and most preferably 1,000 to 6,000.

Suitable polyesters with hydroxyl groups include, for example, the reaction products of polyhydric, preferably dihydric alcohols to which trihydric alcohols, may be added and polybasic, preferably dibasic carboxylic acids. Instead of rree polycarboxylic acids, the corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof may be used for preparing the polyesters. The polycarboxylic acids may be aliphatic, cycloaliphatic, aromatic and/or heterocyclic and they may be substituted, e.g., by halogen atoms and/or unsaturated. The following are mentioned as examples of LeA 17,468 -7-~s~

useful acidic materials: succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, trimellitic acid, phthalic acid anhydride, tetrahyclro-phthalic acid anhydride; hexahydrophthalic acid anhydride;
tetrachlorophthalic acid anhydride; endomethylene tetra-hydrophthalic acid anhydride; glutaric acid anhydride; male:ic acid, maleic acid anhydride, fumaric acid, dimeric and trimeric fatty acids such as oleic acid which may he mixed with mono-meric fatty acids; dimethyl terephthalate and terephthalic acid-bis-glycol esters, and the like. The following are~
examples of suitable polyvalent alcohols: ethylene glycol, propylene glycol (1,2~ and -~1,3), butylene glycol-(1,4) and -(2,3), hexanediol-(1,6), octanediol-(1,8), neopentylglycol, cyclohexanedimethanol (1,4-bis-hydroxymethylcyclohexane), 2-methyl-1,3-propanediol, glycerol, trimethylolpropane, hexanetriol-(1,2l6), butane~riol-(1,2,4), trimethylolethane, pentaerythritol, quinitol, mannitol and sorbitol, methyl-glycoside, diethylene glycol, triethylene glycol, tetra-ethylene glycol, polyethylene glycols, dipropylene glycol, polypropylene glycols, dibutylene glycol, poly~utyIene glycols, and the like. The polyesters may also contain a proportion of carboxyl end groups. Polyesters of lactones such as ~-caprolactone or hydroxycarboxylic acids such as (~-hydroxycaproic acid may also be used.

The optional hydroxyl polyethers used according to the invention which have at least 2, generally 2 to 8 and preferably 2 to 3 hydroxyl groups (which are not primary hydroxyl groups) are also known and are prepared, for example, by polymerizatlon of epoxides such as ethylene oxides, v Le~ 17,468 -8-s' : -, ~lS,~

propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin, either alone, e.g., in the presence of boron trifluoride, or by addition of these epoxides, either as mixtures ox succes~ively, to starting components having reactive hydrogen atoms, such as water, alcohols, ammonia or amines. Suitable starting components include ethylene glycol, propylene glycol-(1,3) or -(1,2), trimethylolpropane, 4,4'-dihydroxy diphenylpropane, aniline, ethanolamine, ethylene diamine and the like. Sucrose polyethers may also be used accord~ng to the invention, e.g., those described in German Auslegeschriften 1,176,358 and l,064,938. All these poly-ethers are substantially free from primary hydroxyl groups.

Particularly to be mentioned among the polythio-ethers are the condensation products obtained by reacting thiodiglycol on its own and/or with other glycols, dicarboxylic acids, formaldehyde, aminocarboxylic acids or arnino alcohols.
The products obtained are polythio mixed ethers, polythio ether esters or polythio ether ester amides, depending on the cocomponents.

Suitable polyacetals include, for example, the com-pounds which can be prepared from glycols such as diethylene glycol, triethylene glycol, 4,4'-dioxethoxydiphenyl dimethyl-methane, hexanediol and formaldehyde. Suitable polyacetals for the purpose of the invention may also be prepared by the polymerization of cyclic acetals.

The polycarbonates with hydroxyl groups used may be of the kind known in the art. Such as, for examples, those Le~ 17,468 -9-1 ~ ,' 9~aD

which can be prepared by the reaction of diols such as propanediol-(1,3), butanediol-(1,4) and/or hexanediol-(l t 6), diethylene glycol, triethylene glycol or tetraethylene glycol with diarylcarbonates, e.g., with diphenylcarbonate or phosgene.

Suitable polyester amides and polyamides include, for example~ the predominantly linear condensates prepared from polyvalent saturated and unsaturatecl carboxylic acids or their anhydrides and polyvalent saturated and unsaturated amino alcohols, diamines, polyamines and mixtures thereof.

Polyhydroxyl compounds already con~aining urethane or urea groups and modified or unmodified natural polyols 5uch as castor oil, carbohydrates or starch may also be used.
Addition products of al]cylene oxides and phenol formaldehyde resins or of alkylene oxides and urea formaldehyde resins are also suitable for he purpose of the invention.

Representatives of the many compounds which may be used according to the invention are known and have heen described, for example, in High Polymers, Volume XVI, "Poly-urethanes, Chemistry and Technology" by Saunders Frisch, Interscience Publishers, New York, London, Volume I, 1962, pages 32 - 42 and pages 44 - 45 and Volume II 7 1964, pages 5 - 6 and 198 - 199 and in Kunststof~-Handbuch, Volume VII, Vieweg-Hochtlen, Carl-Hanser-Verlag, Munich, 1966, e.g., on pages 45 to 71.

Mixtures of the above-mentioned compounds which contain at least two hydrogen atoms capable of react:ing with LeA 17,468 -10-9~

isocyanates and have a molecular weight of from 400 to 1()l00 may, of course, also be used, for example, mixtures of poly-ethers and polyesters.

The starting componnts used according to the inven-tion may also include compounds with a molecular weight of from 32 to 400 which have at least two hydrogen a-toms capable of reacting with isocyanates in amounts of up to 50%, by weight, based on the weight of primary hydroxyl group con-taining polyethers. These materials include compounds con-taining hydroxyl groups and/or amino groups and/or thiol groups and/or carboxyl groups, preferably hydroxyl groups and/or amino groups, and they serve as chain-lengthening agents or cross-lillklng agenks. They generally have from 2 to 8 hydrogen atoms capable of reacting with isocyanates, pre-ferab1y 2 or 3 such hydrogen atoms. ~he following are examples of such compounds: ethylene glycol, propylene glycol-(1,2) and (1,3), butylene glycol-(1,4) and -(2,3), pentanediol-(1,5), hexanediol-(1,6), octanediol-(1,8), neopentyl glycol, 1,4-bis-hydroxymethyl-cyclohexane, 2-methyl-1,3-propanediol, glycerol, trimethylol propane, hexanetriol-(1,2,6), trimethylol-ethane, pentaerythritol, quinitol, mannitol and sorbitol, diethylene glycol, triethylene glycol, tetraethylene glycol r polyethylene glycols with a molecular weight of up to 400, dipropylene glycol, polypropylene glycols with a molecular weight o up to 400, dibutylene glycol, polybutylene glycols with a molecular weight of up to 400, 4~4'-dihydroxy-diphenyl propane, dihydroxymethyl-hydroquinone, ethanolamine, diethanol amine, triethanolamine, 3 aminopropanol, ethylene diamine, ' LeA 17,468 ;' : `

~L5~

1,3-diaminopropane, l-mercapto 3-aminopropane, 4-hydroxy-phthalic acid, 4-aminoph-thalic acid, succinic acid, adipic acid, hydrazine, N,N-dimethylhydrazine, 4,4'-diaminodiphenyl-methane, tolylenediamine, methylene-bis-chloraniline, methylene-bis-anthranilic acid ester, diaminobenzoic acid esters, the isomeric chlorophenylene diamines, and the like.

In this case, again there may be used mixtures of various compounds having a molecular weight of from 32 to 400 and containing at least two hydrogen atoms capable of reacting with isocyanates.

According to the invention, polyhydroxyl compounds in which high molecular weight polyadducts or polycondensates are finely dispersed or dissolved may also be used in quantities of up to 50% by weight based on the primary hydroxyl lS group containing polyether. These modified polyhydroxyl com-pounds are obtained when polyaddition reactions, e.g., reactions between polyisocyanates and amino functional com-pounds, or polycondensation reaotions, e.g., between formalde-hyde and p,henols and/or amines, are carried out ln situ in any of the above-mentioned hydroxyl compounds. Processes of this kind have been described, for example, in German Auslege-schriften 1,168,075 and 1,260,142 and in German Offenlegung-sschriften 2,324,134: 2,423,984; 2,512,385; 2,513/185;
2,550,796; 2,550,797; 2,550,833 and 2,550,862. Alternatively, these modified polyhydroxyl compounds may be obtained according to U. S. Patent 3,869,413 or German Offenlegungsschrift 2,550,860 by mixing a previously prepared aqueous polymer dispersion with a polyhydroxyl compound and then removing the water from the mixture.

LeA 17,468 -12 Accorcling to the invention, water and/or readily volatile organic substances are used as blowing agents.
Suitable organic blowing agents include, for example, acetone, ethyl acetate and halogen substituted alkanes such as methylene chloride, chloroform, ethylidene chloride, vinylidene chloride, monofluorotrichlorome-thane r chlorodifluoromethane, and dichlorodifluoromethane as well as butane, hexane, heptane and diethyl ether. The effect of a blowing agent can also be obtained by the addition of compounds which decompose at temperatures above room temperature to release gases such as nitrogen, e.g., azo compounds such as azoisobutyric acid nitrile. Further examples of blowing agents and the use o~
blowing agents are known and have been described, e.g., in Kunststoff-Handbuch, Volume VII, published by Vieweg and Hochtlen, Carl-Hanser-Verlag, Munich 1966, e.g., on pages 108 and 109, 453 to 455 and 507 to 510.

Catalysts are also ~requently used accordin~ to the invention. The catalysts added are generally known and include tertiary amines such as triathylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, N-cocomorpholine, N,N,N',N'-tetramethyl-ethylenediamine, 1,4-diaza-bicyclo-(2,2,2)-octane, N-methyl-N'-dimethyl-aminoethylpiperazine, N,N-dimethylbenzylamine, bis-(N,N-diethyl-aminoethyl)-adipate, N,N diethylbenæylamine, pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamlne, N,N,N',N'-tetramethyl-1,3 butane-diamine, N,N-dimethyl-6-phenylethylamine, 1,2-dimethylimi-dazole and 2-methylimidazole. Mannich bases known per se obtained from secondary amines such as dimethylamine and LeA 17,468 -13 , ~ , `~ ~

~5~

aldehydes, preferably formaldehyde, or ketones such as acetone, methyl ethyl ketone or cyclohexanone and phenols such as phenol, nonylphenol or bis-phenol may also be used as catalysts.
Examples of catalysts which consist of tertiary amines having hydrogen atoms which are reactive with isocyanate groups include triethanolamine, triisopropanolamine, N-methyl-diethanolamine, N-ethyl-diethanolamine, N,N-dimethyl-ethanol-amine and their reaction products with alkylene oxides such as propylene oxide and/or ethylene oxide.

Silaamines having carbon-silicon bonds as described, e.g., in German Patent 1,229,290 and U. S. Patent 3,620,984 may also be used as catalysts. Examples include 2,2,4-trimethyl-2-silamorpholine and 1,3-diethylaminoethyl-tetramethyldisiloxane.

Basic nitrogen compounds such as tetraalkylammonium hydroxides, alkali metal hydroxides such as sodium hydroxide, alkali metal phenolates such as sodium phenolate and alkali metal alcoholates such as sodium methylate may also be used as catalysts. ~exahydrotriazines are al50 suitable catalysts.

Organic metal compounds may also be used as catalysts according to the invention, in particular organic tin compounds. The organic tin compounds used are preEexably tin(II) salts of carboxy~ic acids such as tin(II) acetate, tin(II) octoake, tin(II) ethyl hexoate and tin(II) laurate and tin(IV) compounds such as dibutyl tin oxide, dibutyl tin dichloride, dibutyl tin diacetate, di.butyl tin dilaurate, dibutyl~ tin maleate or clioctyl tin diacetate~ ~11 the above--mentioned catalysts may, of course, be used as mixtures.

l~e~ 1~,468 ~14 , Further examples of catalysts which may be use~
according to the inven-tion and details concerning the activity of the catalysts are known and are described, e.g., in Kunststoff-Handbuch, Volume VII, published by Viewe~ and Hochtlen, Carl-Hanser-Verlag, Munich 1966, pages 96 to 102.

The catalysts, when used, are generally used in a quantity of between about 0.001 and 10%, by weight, based on the quantity of primary hydroxyl group containing polyethers.

Surface active additives such as emulsifiers and foam stabilizers may also be used according to the invenlxion.
Suitable emulsifiers include, e.g., the sodium salts of ricinoleic sulphonates or salts of fa-tty acids with amines such as oleic acid diethylamine or stearic acid diethano]-amine. Alkali metal or ammoni~n salts of sulphonic acids such as dodecylbenzene sulphonic acid or dinaphthylmethane disulphonic acid or of fatty acids such as ricinoleic acid or of polymeric fatty acids may also be used as surface active additives.

Polyether siloxanes are particularly suitable foam stabilizers, especially useful are those which are water soluble. These compounds generally have a polydimethyl siloxane group attached to a copolymer of ethylene oxide and pxopylene oxide. Foam stabilizers of this kind are known and have been described, ~or e~ample, in U. S. Patents 2,834,748;
2,917,480 and 3,629,308. It may, however, be advantageou;, to carry out the process according to the invention without Eoam stabilizers.

LeA 17,468 -15-~5~

Other additives which may also be used according to the invention include reaction retarders, e.g., substances which are acid in reaction such as hydrochloric acid or orga:nic acid halides, cell regulators such as paraffins or fatty S alcohols or dimethyl polysiloxanes, pigments, dyes, flame retarding agents such as tris-chloroethyl phosphate, tricresyl phosphate or ammoni~n phosphate and polyphosphates, stab:ilizers against ageing and weathering/ plasticizers, fungistatic and bacteriostatic substances, and fillers such as barium sulphate, kieselguhr, carbon black or whiting.

Qther examples o:f surface active additives, foam stabilizers, cell regulators, reaction retarders, sta~
zersj flame retarding substances, plasticizers, dyes, fillers, and fungistatic and bacteriostatic substances which may be used according to the invention and details concerning the use and mode of action of these additives are known and may be found, e.g., in Kunststoff-Handbuch, Volume VII, published by Vieweg and Hochtlen, Carl-Hanser-Verlag, Munich 1966, on pages 103 to 113.

According to the invention, the components may be reacted together by the known one-shot prepolymer or semi-prepolymer process, often using mechanical devices such as those described in U. S. Patent 2,764,565. Details concerning pxocessing apparatus which may be used according to the inven-tion may be found in Kunststoff-Handbuch, Volume VII, published by Vieweg and Hochtlen, Carl-Hanser-Verlag, Munich 1966, pages 121 and 205.

Le~ 17,468 -16-According to the invention, the foaming reaction i-or producing foam products is ~ften carried out inside molds. In this process~ the foamable reaction mixture is introduced into a mold which rnay be made of a metal such as aluminum or a plastics material such as an epoxide resin. The reaction mixture foams up inside the mold to produce the shaped product.
The process of foaming in molds may be carried out to produce a product having a cellular structure on its surface or it may be carried out to produce a product having a compact skin and cellular core. ~ccording to the invention, the desired result can be obtained by either introducing just sufficient foamable reaction mixture to fill the mold with foam after the reaCtiQn is completed or introducing a larger quantity of reaction mixture than is necessary to fill the mold with foam. The second method is known as "overpacking", a procedure whi~h is known and has been disclosed, 2 . g ., in U. S. Patents 3,178,490 and 3~182,1~4.

So-called external mold release agents known in the art, such as silicone oils, are frequently used when foaming is carried out inside molds. The process may also be carri~d out with the aid of so-called internal mold release agents, i~
desired, in combination with external mold release agents, e.g., as described in German Offenlegungsschriften 2,121,670 and 2,307,589.

Cold setting foams may also be produced, as described~
in British Patent 1,162,517 and German Offenlegungsschrift 2,153,086.

LeA 17,46B -17-~, ~XlS9~V~

Foams may, of çourse, also be produced by the process of block foaming or by the laminator process known in the art. The products obtainable according to the inven~
tion may be used, for example, as upholstery or paddlng materials. : :

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~ ~ LeA 17,458 ;~ ?

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EXAMP~ES
-In all examples metal molds were used~ Foaming was c~rried out at a mold temperature of 50~.

Example 1 (Comparison Example) A) 100 parts by weight of a polypropylene glycol which had been started on trimethylolpropane and modified with ethylene oxide, having a hydroxyl number of 28 with 80% of primary hydroxyl end groups, 3.2 parts by weight of water, 0~15 parts by weight of diazabicyclo-2,2,2-octane, 0.10 parts by weight of 2,2'-dimethyl-aminodiethylether, and 5 parts by weight of trichlorofluoromethane and B:) 54.8 parts by weight of a polyisocyanate mixture con-sisting of 34% by weight of 2,4'-diphenylmethane diisocyanate, : :l5 51% by weight of 4,4'-diphenylmethane diisocyanate, and 15% ~y welght of oligomeric polyphenylpolymethylene poly-: isocyanates were reacted together in~a closed mold. Moldrelease time: 8 minutes.

A molded foam product havi~g the following mechanical properties was obtained:
Gross density DIN 53420 (kg/m3) 44 Tensile strength DIN 53571 (KPa) 130 Elongation at break DIN 53571 (%) 150 Compression strength DIN 53577 (KPa~ s.4 .
~ LeA 17,468 ~ ~19-~",~

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Example 2 A) 100 parts by weight of a polypropylene glycol which had been started on trimethylolpropane and modified with ethylene oxide, having a hydroxyl number o 28 and 85% of primary hydroxyl end groups, 2.7 parts by weight of water, 0.33 parts by weight of diazabicyclo-2,2,2-octane, 0.1 parts by weight of 2,2' dimethyl-aminodiethylether, 0.5 parts by weight of N methylmorpholine, 0.02 parts by weight of ibutyl tindilaurate, 1.5 parts by weight of gly~erol, and 8 parts by weight of trichlorofluoromethane and B) 54.0 parts by weight of a polyisocyanate mixture con-sisting of 5~i by weight of 2,4'-~iphenylmethane diisocyanate, 80~i by weight of 4,4'-diphenylmethane diisocyanate, and 15~i by weight of oligomeric polyphenyl polymethylene poly~
isocyanates were reacted together in a closed mold. Mold release time: 1 minute.

The molded foam product having the following mechanical properties was obtained:
Gross density ~l DIN 53420 (kg/m ) 43 Tensile strength ' DIN 53571 (KPa) 105 Elongation at break ~,.DIN 53571 (~i) 130 Compress.i.on strength ~ DIN 53577 (KPa) 5.8 , I ~

LeA 17,463 -20-:

~5~
Example 3 A) 100 parts by weight of a polypropylene glycol which has been started on trimethylolpropane and modified with ethylene oxide, having a primary hydroxyl end group content of 75% and a hydroxyl number of 35, 2.7 parts by weight of water~
0.33 parts by weight of diazabicyclo-2,2,2-octane, 0.06 parts by weight of 2,2'-dimethyl-aminodiethylether, 0.5 parts by weight of N-methylmorpholine/
: 10 0.2 parts by weight of dibutyl tindilaurate, 1.5 parts by weight of glycerol, and 8 parts by weight of trichlorofluoromethane, and B) 50.4 parts by weight of a mixture of 80~ by weight of polyisocyanate mixture consisting of ~ 10% by weight of 2,4'-diphenylmethane diisocyanate, : 75~ by weight of 4,4'-diphenylmethane diisocyanate, ancl 15% by weight of oligomeric polyphenyl polymethylene poly-: isocyanates; 20% by weight of tolylene diisocyanate (2,4- :
2,6-isomer as 80 : 20% by weight) were reacted to~ether in a closed mold. Mold release time: 1 minute, 30 seconds.

A molded foam product having the following mechanical properties was obtained:
Gross density DIN 53420 (kg/m3) 42.5 Tensile strength DIM 53571 (KPa) 85 Elongation at break DIN 53571 (~) 145 Compression strength ~ DIN 53577 (KPa) 4.7 LeA 17,468 -21-Example 4 A) 100 parts by weight of a polypropylene glycol which has been started on glycerol and modified with ethylene oxide~
having a primary hydroxyl end group content of 80~ and a hydroxy] number of 28, 3.0 parts by weight of water, 0.55 parts by weight of diazabicyclo-2,2,2-octane, 0.06 parts by weight of 2,2'-dimethyl-aminodiethylether, and 5 parts by weight of trichlorofluoromethane and B) 51.75 parts by weight of a polyisocyanate mixture con-sisting of 26~ by weight of 2,4'-diphenylmethane diisocyanate, 64% by weight of 4/4'-diphçnylmethane diisocyanate, and 10~ by weight of oligomeric polyphenyl polymethylene poly-isocyanates were reacted together in a closed mold. Mold release time: 2 minutes, 30 seconds.

A molded foam product having the following mechanical properties was obtained:
Gross density DIN 53420 (kg/m3)56 Tensile strength DIN 53571 (KPa) 200 Elongation at break DIN 53571 1~) 185 Compression strength ~IN 53577 (KPa) ~j.3 When the same reaction mixture is produced via tle free use technique, the resulting foam had the following mechanical properties:
Gross density DIN 53420 (kg/m3)44 Tensile strength DIN 53571 (KPa) 110 Elongation at break DIN 53571 (~) 180 Compression strength DIN 53577 (KPa) 3.2 LeA 17,468 -22-q Example 5 A) 100 parts by weight o a polypropylene glycol which has been started on trime-thylolpropane and moclified with ethylene oxide, having a primary hydroxyl end group content of 80'~ and a hydroxyl number of 28, 2.7 parts by weight oE water, 0.20 parts by weight of diazabicyclo-2,2,2-octane, 0.06 parts by weight of 2,2'-dimethyl-aminodiethylether, and 5 parts by weight of trichlorofluoromethane and B) 48.8 parts by weight of a polyisocyanate mixture con-sisting of 10~ by weight of 2,4'-diphenylmethane diisocyanate, 60~ by weight of 4,4'-diphenylmethane diisocyanate, and 30% by weight of oligomeric polyphenyl polymethylene poly-isocyanates were reacted together in a closed mold. Mold release time: 2 minutes.

A molded foam product having the following mechanical properties was obtained:
Gross density DIN 53420 (kg/m3) 43 Tensile strength DIN 53571 (KPa) 80 Elonyation at break DIN 53571 (%) 105 Compression strength DIN 53577 (KPa) 3.8 LeA 17,468 ~ -23~
,: :

~5~

Example 6 A) 100 parts by weight of a polypropylene glycol which had been started on trimethylolpropane and modified with ethylene oxide, having a hydroxyl number oE 28 with 60~ of primary hydroxyl end groups, 3.0 parts by weight of water, 0.5 parts by weight of diazabicyclo-2,2,2-octane~
0.06 parts by weight of 2,2'-dimethyl-aminodiethylether, and S parts by weight o~ trichlorofluoromethan~ and B) 51.7S parts by weight of a polyisocyanate mixture con-sisting of 26% by weight of 2,4'-diphenylmethane diisocyanate, 69~ by weight of 4,4' diphenylmethane diisocyanate, and 5~ by weight of oligomeric polyphenylpolymethylene poly-isocyanates were reacted together in a closed mold. Mold release time: 2 minutes, 30 seconds.

A molded foam product having the following mechanical properties was obtained:
Gross density DIN 53420 (kg/m3)51 Tensile strength D~N 53571 (KPa)205 Elongation at break DIN 53571 (%) 215 Compression strength DIN 53577 (KPa) 5 LeA 17,468 1~ -24-Example 7 Preparation of a flexible integral skin foam.
95 parts by weight of a polypropylene glycol which has been started on trimethylolpropane and modified with ethylene oxide, having a primary hydroxyl end group content of 80~ and a hydroxyl number of 28, ethylene ~lycol 5 parts by weight, water 0.4 parts by weight, diazabicyclo-2,2,2-octane 0.35 parts by weight, tetramethyl ethylenediamine 0.5 parts by weight, and trlchlorofluoromethane 8 parts by weight were stirred toyether. They were then mixed with 28.0 parts by weight of a polyisocyanate mixture consisting of 2,4'-diphenylmethane diisocyanate 10~ by weight I5 4,4'-diphenylmethane diisocyanate 75% by weight oligomeric polyphenyl polymethylene polyisocyanates 15% by weight The reaction mixture was poured into a closed mold.
A molded foam product having an integral skin (soft integral foam) was obtained. It had the following properties:
Gross density DIN 53420 Ikg/m ) 105 Tensile strength DIN 53571 (KPa) 135 Elongation at break DIN 53571 (%~ 115 Compression resistance DIN 53577 (KPa) 13.5 The mold release time was 2 minutes.

LeA 17,468 -25~

Claims

WHAT IS CLAIMED IS:

1. In a process for the production of molded cold setting, flexible foams, having a cellular structure on the surface thereof, which foams contain urethane groups by the reaction in a mold of polyethers with a molecular weight of 400 to 10,000 which contain at least two hydroxyl groups and in which at least 10% by weight of the hydroxyl groups are primary hydroxyl groups, mixed with a mixture of diphenyl methane diisocyanates and oligomeric polyphenyl-polymethylene-polyisocyanates in the presence of blowing agents and in the presence of one or more amine catalysts and optionally other catalysts and foaming aids, the improvement wherein the mixture of diphenyl methane diisocyanates and poly-phenyl-polymethylene polyisocyanates is substantially free of carbodiimide groups, and contains from 60 to 90%
by weight of 4,4' diphenyl methane diisocyanate and from 3 to 30% by weight of 2,4' diphenyl methane diisocyanate wherein the reaction is carried out in the absence of foam stabilizers and wherein the amine catalysts are selected from the group consisting of diazabicyclo-2,2,2-octane, 2,2'-dimethyl-aminodiethyl ether, tetramethyl ethylene diamine, and N-methyl morpholine.

2. The process of Claim 1, wherein said mixture contains 65 - 80% by weight of 4,4' diphenyl methane diisocyanate and 10 - 30% by weight of 2,4' diphenyl methane diisocyanate.

3. The urethane group containing foam produced according to the process of Claim 1.