CA2045192C - Preparation of cellular plastics by the polyisocyanate polyaddition process in the presence of tertiary alcohols - Google Patents

Abstract

A process for the preparation of cellular plastics, preferably hard structural poly-urethane foams, by the polyisocyanate polyaddition process involves reacting a) an organic and/or modified organic polyisocyanate with b) at least one high-molecular-weight compound contain-ing at least two reactive hydrogen atoms and, if desired, c) a low-molecular-weight chain extender and/or cross-linking agent, in the presence of d) a blowing agent from the group comprising tertiary alcohols (di), preferably tertiary butanol, or a mixture of at least one tertiary alcohol (di) and water (dii), e) a catalyst and, if desired, f) assistants and/or additives.

Description

The present invention relates to a process for the preparation of cellular pla6tics, especially integral skin moldings having a compacted peripheral z:one and a cellular core comprised of a polyurethane and/or polyisocyanurate polymer, comprising reacting:
a ) an organic polyisocyanate with b) at least one high-molecular-weight compound containing at least two reactive hydrogen atoms, with the exception of olefinically unsaturated polyesters or alkyd resins, lo and, if desired, c ) a low-molecular-weight chain extender and/or cross-linking agent, in the presence of d) an acid free blowing agent containing at least one tertiary alcohol and preferably a mixture of at least one tertiary alcohol and water, e) a catalyst in an amount effective to promote urethane and/or isocyanurates linkages, and, if desired, f ) assistants and/or additives.
The preparation of cellular polyisocyanate polyaddition products, for example cellular polyurethane elastomers and flexible, semihard or hard polyurethane foams, by reacting an organic polyisocyanate and/or a modif ied organic polyisocyanate witll a high-molecular-weight compound containing at least two reactive hydrogen atoms, for example a polyoxyalkylene-polyamine and/or preferably an organic polyhydroxyl compound having a molecular weight of, for example, from 500 to 12,000, and, if desired, a chain extender and/or cross linking agent ~laving a molecular weight of about 30 500, in the presence of a catalyst, a blowing agent, assistants and/or additives has been disclosed in numerous patent and other publications. 13y a suitable choice of the B~ 2 polyisocyanate, the high-molecular-weight c ~t~nlng reactive ~Iy~ ~yt~l ntoms and, lf used, the chain Yt~n l~r and/or crosslinXing agent, this method allows the prep2r2tion of elastic or rigid, c~ 1 ul ~r polyisocyanate polyaddition products and or modifications in between.
A review on the preparation of c~ l Ar poly-urethane (PU~ el2stomers, polyurethane (PU~ foams and polyisocyanurate (PIR~ foams and moldings having a compacted peripheral zone and a cellular core made from polyaddition products of this type, their ~~bAnir~l properties and their use is given, for example, in the monographs High Polymers, Volume XVI, Polyurethanes, Parts I and II by J.H. SA~nr~rs and ~.C. Frisch (Inter-science pl~hli~h~rs, NewYork 1962 and 1964 respectively~, l~unststoff-7~n~hurh, Volume VII, Polyurethane, 1st Edition, 1966, edited by Dr. R. Vieweg and Dr A. Hochtlen and 2nd Edition, 1983, edited by Dr G. Oertel (Carl Hanser Verlag, ~unich~ and IntergrA ~ch~lm~toffe, edited 2 0 by Dr H . Piechota and Dr H . Rohr ( Carl Hanser Verlag, ~lunich, Vienna, 1975 ~ .
The preparation of CDl 1 ~11 Ar plastics by the polyisocyanate polyaddition process uses essent$ally two types of blowing agent:
10w-boiling, inert liguids which evaporate under the influence of the exothermic polyadditlon re2ction, for example alkanes, such as butane, pentane, inter alia, or preferably halogenated hydrori~rhon~, 6uch as methylene chloride, dichloromonofluoromethane, trirhl~rofluoro-methane, inter alia, nnd rh~ rAl c sunds which ~orm blowiny gases by a rh~m~rAl reaction or thermal dec _ 6ition. Examples which may be mentioned are the reaction of water with isocyanates to form amines and carbon di-oxide, which proceeds ~ynchronously with the polyurethane preparation, and the cleavage of th -rr l ly labile com-pounds, for example azoisobutyronitrile, which gives, as a cleavage product, toxic tetramethylsuccinodinitrile in 3 204~
, additlon to nitrogen, or ~7o~icArho~mirio~ the use of ~hich as ~ constituent of ~ blowLng agent co~inatlon is dosrrihed in EP-A 0 Og2 740 (CA 1,208,912). While the last-mentioned method, in which the thorr-l ly labile _ '~, for example azo _u--~s, hydrazides, semi-CArhA7irloC~ N-nitroso _ -c, bon7nYA7inos~ inter alia, (~unststoffe 66 (1976), 10, pages 698 to 701), are usually inco-~o- ated into a previously prepared polymer or drum-coated on to the plastic granules and f~amed by extrusion, have ~ nod of minor industrial importance, the physical, low-boiling liquids, in particular chloro-fluoroAlkAnocl are used world-wide on a large scale for the preparation of polyurethane foams or polyisocyanurate foam~ he only dLsadvantage of these blowing gases is environmental pollution. By contrzst, when blowing gases are formed by thermal cleavage or rhomirAl reaction, cleavage products andfor reactive byproducts are produced and are included in the polyaddition product or rhomirAl-ly bonded and may result in an undesired change in the ^hAnic~l properties of the plastic. In the ca~e of the formation of carbon dioxide from water and isocyanate, urea groups are formed in the polyaddition product, and, rlopon~linr on their amount, may result in an i uv L
in the compressive strength as far as embrittlement of the polyurethane.
The h~nicm of foam formation in the prepara-tion of polyisocyanate polyaddition products and the effect of surface-active assistants based on siloxane-oxaalkylene copolymer_ on this reaction has been descri-bed by B. ~anner et al. (J. of C~o~ Ar Plastics, January 1969, pages 32 to 39 ) .
According to these and other publications, an es6ential requirement for the formation of coll~lAr polyisocyanate polyaddition products having a uniform cell structure and good --h~nirAl properties is a - us solution of the blowing agent, for example the carbon dioxide nnd/or the inert, low-boiling liquid, _4 - 2n~ 2 in the organic polyisocyanate and/or the ~ _ ~
~ontA~nin~ reactive l~yd~oy~ atoms ~Blowing Agents for Polyurethanefi, by L.~l. Zwolinski in Rubber Age, July 1975, pages 50 to 55, and GB-A-904,003). If the blowing agent is not soluble in the ab.~,~ Lioned _ ~ ts, only large-pore foams or in most cases no foams at all are obtained.
In order to avoid this disadvantage, US-A-4,544,679 j~.uj~sed employing specific polyol mix-tures of increased chlorofluorohydrocarbon solubility and/or it is attempted to obtain h' -Iy~ OUS solutlons of blowing agent and polyisocyanate and/or polyol by adding in some cases considerable amounts of solllhi 1 i 7-,rS
(R. Tanabe, I. lri r?~ and S. Rozawa, 28th SPI
Conference, 1984, pages 53 to 57).
Furt~ , DE-B-l 126 131 ~US 2, 865, 869 ) Aicrlosos a process for the preparation of polyester-polyurethane foams by reacting an alkyd resin and a polyisocyanate with addition of a reaction material which forms a gas at elevated tL_.jt,e.~.Lure. Suitable gas-forming reaction materials are mixtures of tertiary alcohols and a catalytically effective amount of an inorganic or organic conr~nt-ated acid, eg. sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, picric acid or trifluoroacetic acid, or 2 Lewis acid, eg. aluminum chloride or boron trifluoride. A disadvantage of polyester-urethane foams of this type is their low ~tability to hydrolysis. Due to the formation of new carboxyl groupi~ by hydrolysis of the ester groups, hydrolytic degradation of the polyaddition product is additionally accelerated autocatalytically, fiO that the polyester-urethane foams prepared on the basis of olefin-ically unsaturated polyesters and preferably mixtureS of 2, 4- and 2, 6-tolylene diisocyanate have only inadequate -~hi~n;cal properties. The patent does not ~ srrihe processes for the preparation of ~!SLLU- LuLGl foams and microcol 1 ul Ar moldings by reaction injection molding 5- 2o4~192 (RIM) .
It is an object of the present invention to improve the flow properties of reaction mixtures for the preparation of polyisocyanate polyaddition products, making possible uniform filling of the mold, even under pressure, by reaction injection molding (RIM), and giving moldings having a smooth, essentially pore-free surface.
A further object was to replace the fluorochlorohydrocarbons known as blowing agents for the 10 preparation of cellular plastics by the polyisocyanate polyaddition process by other, environmentally friendly blowing agents.
It ha6 now been found that, surprisingly, these objects can be achieved by using a tertiary alcohol, in the pre6ence or absence of water, as the blowing agent.
The present invention accordingly provides a process for the production of integral skin moldings having a compacted peripheral zone and a cellular core comprised of a polyurethane or polyisocyanurate polymer, comprising reacting:
20 a) an organic polyisocyanate with b ) at least one high-molecular-weight compound containing at least two reactive hydrogen atoms and, if desired, c ) a low-molecular-weight chain extender and/or cross-linking agent, in the presence of d) an acid free blowing agent selected from the group consisting of di ) at least one tertiary alcohol having one isocyanate reactive hydrogen; and dii) at least one tertiary alcohol in admixture with water;
e ) a catalyst in an amount ef f ective to promote urethane and/or isocyanurate linkages, and, if desired, f ) assistants and/or additives, in a closed mold with compaction.
.,,:D.

The presence of a tertiary alcohol considerably improves the f low propertie5 of the reaction mixture so that it is possible to fill even large-volume molds having complicated geometries uniformly. Moldings having uniform mechanical properties are consequently obtained. I~lthough the foaming i8 carried out in the absence of physical blowing agents and preferably in the presence of carbon dioxide formed by reaction of water with polyi60cyanates, cellular moldings having an essentially pore-free, highly pronounced peripheral 10 zone and a compact, smooth surface are obtained with compaction in a closed, expediently thermostatted mold. this highly pronounced peripheral zone occurs, in particular, in the preparation of urethane-containing hard structural foams having an overall density of from 0 . 3 to 1 g/cm3, i .e.
thermosets. The mechanical properties of the thermoset6 prepared according to the invention are at least comparable, but usually better than those of products foamed using trichlorofluoromethane; however, the homegeneity of mechanical properties over the entire molding is advantageous, and 20 therefore worthy of note.
The following applies to components (a) to (f ), in particular the blowing agents (d) which can be used according to the invention, for the preparation of the cellular polyisocyanate polyaddition products, preferably the urethane-o ~

-foams: 20~5192 a) Suitable organic polyisocyanates are the conventional aliphatic, cycloaliphatic, ~r2~ hAtic and preferably ~romatic polyisocyanates.
The followlng may be ~nn~cl as examples:
alkylene dilsocyanates havLng from 4 to 12 carbon atoms in the alkylene moiety, such as 1,12-dodecane dLisocyanate, 2-ethyltetramethylene 1, 4-diisocyanate, 2-methylpentamethylene 1, 5-diisocyanate, tetra-methylene 1,4-diisocyanate and prefera~ly hexa-methylene 1,6-diisocyanate; cycloaliphatic diisocyanates, such a5 cycloh~YAno 1,3- and 1,4-diiso-cyanate and any desired mixtures of these isomers, l-isocyanato-3, 3, 5-trimethyl-5-isocyanatomethylcyclo-hexane (isophorone diisocyanate), 2,4- and 2,6-hexa-hydrotolylene diisocyanate, and the coL~ onding isomer mixtures, 4,4'-, 2,2'- and 2,4'-dicyclohexyl-methane diisocyanate and the COl~ ~u.~ding isomer mixtures, and preferably arom~tic diisocyanates and polyisocyanates, eg. 2,4- and 2,6-tolylene diiso-cyanate and the cc, as~.,nding isomer mixtures, 4,4~-, 2, 4 ~ - and 2, 2 ' -diphenylmethane diisocyanate and the co, as~ol,ding isomer mi~ctures, mixtures of 4,4~- and 2, 4 '-diphenylmethane diisocyanates, polyphenyl-poly-methylene polyisocyanates, mixtures of 4, 4 ~ -, 2, 4 ~ -and 2,2~-diphenylmethane diisocyanates and polyphenyl-polymethylene polyisocyanates (crude ~qDI), preferably those having a diphenylmeth~ne dii~ocyanate isomer content of from 30 to 80% by weight, based on the weight of crude ~T, and mixtures of crude ~I and tolylene di$socyanates. ~rhe organic diisocyanates and polyisocyanates may be enLployed individually or in the form of mixtures.
Fl~=~u_l-Lly, - ' i f i ~d polyisocyanates are also used, ~e. plGdu- ~ which are obtained by rhDmiCAl reaction of organic diisocyanates and~or polyiso-cyanates. Specific ~ are ester-, urea-, - _ j - 8 - 2 0 451~2 biuret-, Al lophAn~te-~ carbodiimLde-, isocyanurate-, uretdione- ~ndJor urethane-containing diisocyanates ~nd/or polyisocyanates. Individual ~YAmrl~s are urethane-containing organic, preferably aromatic, polyisocyanates cont~1n~n~ from 33.6 to 159~ by weight, preferably from 31 to 21% by weight, of NCO, based on the total weight, for example 4,4'-diphenylmethane diisocyanate or 2, 4- or 2, 6-tolylene diisocyanate ~ i f i e~1 by means of low-molecular-weight diols, triols, dialkylene glycols, trialkylene glycols or polyoxyalkylene glycols having molecular weights of up to 1800, specific ~Y~mr10~C of di- and polyoxyalkylene glycols, which can be employed individually or as mixtures, being diethylene glycol, dipropylene glycol, polyoxyethylene glycol, polyu~yyLu~ylene glycol and polyu.-yyLu~ylene-polyoxyethylene glycol. NCO-contain-ing prepolymers contAining from 25 to 3.5% by weight, preferably from 21 to 14% by weight, of NCO, based on the total weight, and prepared from the polyester-and/or preferably polyether-polyols described below and 4,4 '-diphenylmethane diisocyanate, mixtures of 2, 4 ' - and 4, 4 ' -diphenylmethane diisocyanate, 2, 4-and/or 2, 6-tolylene diisocyanates or crude ~DI are also suitable. Furth- ~, liquid polyisocyanates cnntA~n~n~ c~rho~ mirl~ groups and/or isouy~ uL~Ite rings and cnntA1nin~ from 33.6 to 15% by weight, preferably from 31 to 21% by weight, of NCO, based on the total weight, eg . based on 4, 4 ~ -, 2, 4 ~ - and/or 2, 2 ' -diphenylmethane diisocyanate and/or 2, 4- and/or 2,6-tolylene diisocyanate, have also proved success f ul .
q~he ~ified polyisocyanates may be used alone or mixed with one another or with , ~ i f i ~d organic polyisocyanates, eg . 2, 4 ~ - or 4, 4 ~ -diphenylmethane diisocyanate, crude ~DI or 2,4- and/or 2,6-tolylene diisocyanate .
Further organic polyisocyanates which have " - 9 - 2~1g2 proven part~ Arly successful and are preferred for use for the preparation of C~1 1111Ar elastomers are NCO-contaLning prepolymers c~tA~nin~ from 25 to 996 by weight of NCO, in particular based on polyether- or polyester-polyols ~nd one or more diphenylmethane diisocyanate isomers, advantageously 4,4'--diphenyl-methane diisocyanate andJor modified urethane-containing organic polyisocyanates containing from 33 . 6 to 1596 by weight of NCO, in particular based on 4, 4 '-diphenylmethane diisocyanate or diphenylmethane diisocyanate isomer mixtures, and those which are preferred for the preparation of flexible polyurethane foams are mixtures of 2,4- and 2,6-tolylene diiso-cyanates, mixtures of tolylene diisocyanates and crude MDI or, in particular, mixtures of the ab~ n~d prepolymers based on diphenylmethane diisocyanate isomers and crude ~DI, and that which is preferred for the preparation of hard polyurethane foams or hard polyurethane polyiso~ y~l,.u~ te foams is crude MDI.
b) The high-molecular-weight compounds b) con-taining at least two reactive hydrogen ntoms are rP~e~ ntly those having a functionality of from 2 to 8 and a molecul2r weight of from 400 to 8000. Examples of compounds which have proven successful are polyether-polyamines and/or preferably polyols selected from the group comprising the polyether-polyols, polyester-polyols, prepared from ;~ n~
carboxylic acids and polyhydric alcohols, polythioether-polyols, polyester-amides, hydroxyl-containing polyacetal~ and hydroxyl-c~n~AIn1ns aliphatic polycarbonates, or mixtures of at least two of said polyols. Preference is given to polyester-polyols and/or polyether-polyols. sy contrast, alkyd resins and polyester molding materials containing reactive, ol~flnic~l ly unsaturated double bonds are unsuitable as high-molecular-weight - _ 'R b) containing at least two reactive l~y~.sgen atoms.

lo 2~192 Suitable polyester-polyols may be prepared, for e~ample, from AllrAn~ rArhnYylic acids having from 2 to 12 carbon atoms, preferably All~Ane~lirA~hnYylic acids having from 4 to 6 carbon atoms, or mi~tures of alkAn~irA~hoYylic acids and aromatic polycarboxylic acids and polyhydric alcohols, preferably diols, having from 2 to 12 carbon atoms, preferably from 2 to 6 carbon atoms, and/or alkylene glycols. Examples of l;uitable ~ n~A~rA-hnYylic acids are succinic acid, glutaric acid, adipic acid, suberic acid, a2elaic acid, sebacic acid and ~ rAn~lirArhn~ylic acid.
r l"c Of suitable aromatic polyc2rboxylic ncids are FhthAl ir acid, isophthalic acid and terephthalic acid.
The All~A~ rArhnYylic acids may be used either individually or mixed with one another. The free ~IrArhnYylic acids may also be replaced by the corres-ponding rl;cArhoYylic acid derivatives, for example ~?irArhnYylic acid esters of ~l~rohnlc having 1 to 4 carbon atoms or ~l~rA~hrYylic anhydrides. Preference is given to ~iicarhoYylic acid mixtures comprising ~uccinic acid, glutaric acid and adipic acid in ratios of, for example, from 20 to 35: 35 to 50: 20 to 32 parts by weight, and in particular adipic acid.
~YAmr~ ~c Of dihydric and polyhydric alcohols, in particular diols or alkylene glycols, are ethAn~rl, diethylene glycol, 1, 2- and 1, 3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-p~nt~n~ nl, 1~6_h~YAnF-~linl~ 1~1O-~i~cF~ne~ glycerol and tri-methylolpropane. Preference is given to ethAn~ rl~
diethylene glycol, 1,4-butanediol, 1~5_pent~n~-~inl, 1,6-h~YAn~ol and mixtures of at least two of said diols, in pnrticular mixtures of 1, 4-butanediol, 1, 5 -pen~An~i i ol and 1, 6-h~YAn~ i nl . Furf h~ e:
polyester-polyols made from lactones, eg.
35~-caprolactone, or l-y~y- arboxylic acids, eg.
y~u~y~aproic acid, may also be employed.
The polyester-polyols may be prepared by 2~ gZ~
poly~ orldensing the mixtures of aromatlc and aliphatic ~ Arhoxylic acids and preferably Alk~no~irArhorylic acids and/or derivatives thereof and polyhydric ~lcohols without u~ing a catalyst or preferably in the ~ nce of an est~rif~r~tion catalyfit, ~pe~ ntly in an inert gas atmosphere eg. nitrogen, helium, argon, inter alia, in the melt at from 150 to 250-C, prefer-ably from 180 to 220-C, at atmospheric ~ ~_SbUL~ or under reduced p~2Sb U~ until the desired acid number, which is advantageously less than 10, preferably less than 2, is reached. In a preferred rmhoAi~ the esterification mi~ture is poly. ~ d at the above-~nnPd ~ _Lures under ai -:~heLic ~esbuL~ and subseyuellLly under a pressure of less than 500 moar, preferably from 50 to 150 mbar, until an acid number of from 80 to 30, preferably from 40 to 30, has been reached. Examples of suitable est~rif~ ation catalysts are $ron, cadmium, cobalt, lead, zinc, antimony, magnesium, titanium and tin catalysts in the form of metals, metal oxides or metal salts. However, the polycnn~l~nc~tion may also be carried out in the liquid phase in the presence of diluents and/or entrainers, eg. benzene, toluene, sylene or chlor~h~n7G-nP, for removal of the water of c~n~l~n~ation ~y azeotropic distillation.
The polye~ter-polyols are ~dvantageously prepared by polycondensing the organic polycarboxylic acids and~or derivatives thereof with polyhydric alcohols in a molar ratio of from 1:1 to 1.8, prefer-ably from 1:1.05 to 1.2.
The polyester-polyols obtained preferably have a functionality of from 2 to 4, in particular from 2 to 3, and a molecular weight of from 480 to 3000, prefer-ably from 1200 to 3000, in particular from 1800 to 2500.
However, the preferred polyols are polyether-polyols prepared by conv~nti~nAl ~.v~.esses, for example by anionic polymerization using alkali metal - 12 ~ 9 2 hydroxides, such as sodium hydroxide or potassium hydroxide, or alkali metal A~ YiA~5, such as sodium methoxide, ~odium ethoxide, potassium ethoxide or potassium isu~Luuù,~de as catalysts and with addition of at least one initiator molecule containing from 2 to 8 reactive l-ydLuyt:ll atoms in bound form, or by cationic polymerization using Lewis acids, such as antimony pentachloride, boron fluoride etherate, inter alia, or hl~Arh~n~ earth as catalysts, from one or more alkylene oxides having from 2 to 4 carbon atoms in the alkylene moiety.
Examples of suitable alkylene oYides are tetrahydrofuran, 1,3-propylene oxide, 1,2- and 2,3-butylene oxide, styrene oxide and preferably ethylene oxide and 1, 2-propylene oxide . I'he alkylene oxides may be used individually, alternatively one after the other or as mixtures. Examples of suitable initiator molecules are water, organic ~irArhoxylic acids, ~uch ~s 6uccinic acid, adipic acid, ph1-h~
acid and terephthalic acid, aliphatic and aromatic, unsubstituted or N-mono-, N,N- and ~,N~-dialkyl-substituted riiAmin~s hAving from 1 to 4 carbon atoms in the alkyl moiety, such as unsubstituted or mono-or dialkyl-substituted ethyl-~n~ri~Am~n~, diethylenetri-amine, triethylenetetramine, 1~3-propyl~n~ Amin~
1,3- and 1,4-buty~Pn~rllAm~n~, 1,2-, 1,3-, 1,4-, 1,5-~nd 1,6-hexamethyl~n~ Aminl~, phenyl--n~ Am1n~-C, 2,3-, 2, 4 - and 2, 6-toly~ ~n~ m ~ n~ and 4, 4 ' -, 2, 4 ' - and 2, 2 ~ --1 i Am i n- -l i rh~nylmethane .
Other suitable initiator molecules are alkanolamines, such as ethanolamine, diethanolamine, N-methyl- and N-ethyl-ethanolamine, N-methyl- and N-ethyl-diethanolamine and triethAn~lAmin~, and ~monia. Preference is given to polyhydric alcohols, in particular dihydric to octahydric Alcoh~lR, such as ethAn~ 1, 1, 2- and 1,3-propanediol, diethylene glycol, dipropylene glycol, 1, 4-butanediol, " -13 ~G~51~2 ~ .
1, 6-h~YAn~ i ol, slycerol, trimethylolpropane, penta-erythritol, sorbitol and s_ccharose.
~ he polyether-polyols, preferably polyoxy-propylene- and polyu,.y~Lv~ylene-polyoxyethylene-polyols, have, for the preparation of elastic or ~emi-hard ce~ r polyisocyanate polyaddition products, a functionAlity of, preferably, 2 to 4, in particular 2 and/or 3, and molecular weights of preferably from 1800 to 6000, in particular from 2400 to 4000, and suitable polyoxytetramethylene glycols have a mole-cular weight of up to approximately 3500, ~nd, for the preparation of hard cellular polyisocyanate poly-addition products, in particular ~h- -cts, have a functionality of, preferably, from 3 to 8, in particu-lS lar from 3 to 6, and a molecular weight of preferably from 400 to 3200, in particular from 600 to 2400.
Other suitable polyether-polyols are polymer-~lifiedpolyether-polyolg~ preferablygraftpolyether-polyols, in particular those based on styrene and/or acrylonitrile and prepared by in situ polymerisation of acrylonitrile, styrene or rref~-r~hly mixtures of styrene and acrylonitrile, for example in a weight ratio of from 90:10 to 10:90, preferably from 70:30 to 30:70, -~e~ 7tly in the ab~v, -Lioned polyether-polyols by n method similar to that of German patents ll ll 394, 12 22 66g (us 3,304,273), 3,383,351 and 3,523,093), ll 52 536 (GB 1,040,452) and 11 52 537 tGB 987,618), and polyether-polyol dLsp~r~ion~ which contain, as the disperse phase, usually in an amount of from l to 5096 by weight, preferably from 2 to 25 by weight, for example polyureas, polyhydrazides, polyurethanes c~nt~in~n~ tert-amino groups in bound form, end/or l~ljn~ and are ri~c-~rihed, for example, in EP-s-011 752 (US 4,304,708), US-A-4,374,209 and DE--A--32 31 497.
Like the polyester-polyols, the polyether-polyols can be used individually or in the form of - 14 2~192 . ~
mixtures. To prepare elastic th~- -ets, it may be expedient, for example, to use suitable mixtures of polyether-polyols having molecular weights of up to 2400 and those having molecular weights of from 2800 S to 4000. Furth~ e~ they may be mixed with the yraft polyether-polyols or polyester-polyols and the hydroxyl-contA; n; n~ polyester-amides, polyacetals, polycarbonates and~or polyether-polyamines.
Examples of suitable hydroxyl-contA;n;n5 polyacetals are the _ _ ~c which can be prepared from glycols, such as diethylene glycol, triethylene glycol, 4~4'-dil-ydLu~y~Lhoxydiphenyldimethylmethane~
hF-Y~n-~A;--l and f~ hyde. Suitable polyacetals can also be prepared by polymerizing cyclic acetals.
Suitable hydroxyl-containing polycarbonates are those of a convPnt;t nAl type, which can be pre-pared by reacting diols, such as 1, 3 -propanediol, 1, 4-butanediol and/or 1, 6-h~-~n~ diethylene glycol, triethylene glycol or tetraethylene glycol, with diaryl carbonates, eg. diphenyl carbonate, or phosgene .
The polyester-amides including, for example, the pr~' ;nAntly linear con~?~ncates obtained from polybasic, saturated and/or unsaturated carboxylic acids or anhydrides thereof and polyhydric, saturated and/or unsaturated amino alcohols, or mixtures of polyhydric alcohols and amino alcohols and/or poly-amines .
Suitable polyether-polyamines can be prepared from the abuv ~ioned polyether-polyols by conven-tional processes. Specific examples are the cyano-alkylation of polyoxyalkylene-polyols and subsequent llydl ug~l~ation of the resultant nitrile (US 3~267,050) or the partial or complete amination of polyoxy-alkylene-polyols using amines or ammonia in the plese.-ce of l-y~uy~ll and catalysts (DE 12 15 373).
c ) The polyisocyan~te polyaddition products and - 15 - 20 ~ S 19 2 preferably the ~L u~Lu.~l foams contaLning urethane groups or urethane and isocyanurate groups _ay be prepared with or without the use of chain ~ n~
and/or crosslinking agents. However, it ~nay prove advantageous, in order to modify She -h~n~cAl properties, for example the hardness, to ~dd chain ~t~-n~?~r-C-, crosslinking agents or, if desired, mixtures thereof. The chain ~ and/or cros6-linking agents used are diols and/or triols having a molecular weight of less than 400, preferably from 60 to 300. r ~ C are aliphatic, cyrloAl iph~tic and/or ~rAl Irh;~tiC diols having from 2 to 14 carbon atoms, preferably from 4 to 10 carbon atoms, eg. ethylene glycol, 1,3-propanediol, 1,10-~c~ nF~ O-~ m- and p-dil~y~u~y~y~lr~hY~n~ diethylene glycol, dipropylene glycol and preferably 1,4-but~n~ ol, 1,6-hF-Y~n~ ol and bis ( 2-lly~J.sy~ Lhyl ) hydroquinone, triols, such as 1,2,4- and 1,3,5-tril.y~L~ y~y~ h~AnF~ glycerol and trimethylolpropane, and low-molecular-weight hydroxyl-containing polyalkylene oxides based on ethylene oxide and/or 1,2-propylene oxide, and the ab~,v~ Lioned diols and/or triols ~8 initiator molecules.
C~ Ar polyurethane-polyurea elastomers can be prepared usLng, besides the ab~ on~d diols and/or triols, or a mixture of these, secon~Ary aromatic ~IAmin~C~ primary aromatic ~ min~c~ 3,3~-di-and/or 3,3 ' ,5,5 '-tetraalkyl-substituted ~i ~min~
phenylmethanes as chain extenders or crosslLnking agents .
Specific ~ c of secondary aromatic min~c are N,N~-dialkyl-substituted aromatic min~ which m y be unsubstituted or fiubstituted on the aromatic ring by alkyl r~riic~lc~ having from 1 to 20, preferably from 1 to 4, carbon atoms in the N-alkyl radical, such as N,N~-diethyl-, N,N~-di-sec-pentyl-, N,N'-di-sec-hexyl-, N,N~-di-sec-decyl-, N,N~-dicyclohexyl-p- or -m-phenylene~ min."

-- 16 - 2~192 N,N~-dihethyl-, N,N'-diethyl-, N,N'-diisopropyl-, N,N'-di-sec-butyl- andN,N'-dicyclohexyl-4,4 '-diamino-diphenylmethane and N,N'-di-sec-butylh~n7~-l;nf-.
~ he aromatic ~;Am;n~8 used ~re o~ n~ly those which have at least one alkyl substituent in the ortho-position to the amino groups, are liquLd ~t room aLul:e and are _iscible with ~: _ 7. L (b), in particular the polyether-polyols. Furth~ _, alkyl-substituted meta-phenyl--n~;Amin~s of the f~ le7~

H2~l and/or where R3 and R2 are identical or dif ferent and are methyl, ethyl, propyl or isopropyl, and R1 iB linear or branched alkyl having 1 to 10, preferal71y 4 to 6, carbon atoms, have proven successful.
Particularly successful alkyl ~2~rl;r~ Rl are those in which the hrAnr~;rl~ point is on the Cl carbon atom. Specific examples of r~;rAl~ Rl are methyl, ethyl, isopropyl, l-methyloctyl, 2-ethyloctyl, 1-methylhexyl, 1, l-dimethylpentyl, 1, 3, 3-trimethyl-hexyl, 1-ethylpentyl, 2-ethylpentyl and preferaL71y cyclohexyl, l-methyl-n-propyl, tert-butyl, 1-ethyl-n-propyl, 1-methyl-n-butyl and 1,1-dimethyl-n-propyl.
r 1~ of suitable alkyl-substituted m-phenyl~n~ Am;n~ are 2,4-dimethyl-6-cyclohexyl-, 2-cyclohexyl-4, 6-diethyl-, 2-cyclohexyl-2, 6-iso-propyl-, 2, 4-dimethyl-6- ( l-ethyl-n-propyl ) -, 2, 4-di-methyl-6- ( 1, l-dimethyl-n-propyl ) -, 2- ( l-methyl-n-butyl ) -4, 6-dimethyl-1, 3 -phenyl~A; ~m i n~ . Pref erence is given to 1-methyl-3, 5-diethyl-2, 4- and --2,6-phenyl-~t7~ m;n~-s, 2,4-dimethyl-6-tert-butyl-, 2,4-dimethyl-6-i~ooctyl- and 2,4-dimethyl-6-cyclo-hexyl- 1, 3 m phe.. y 1 ~ m; n~ .

7 - 2~4~192 r l~c of s~àble 3,3'-di- and 3, 3 ~, 5, 5 ' -tetra-n-alkyl-substituted 4, 4 ~ -~ i Am i nnr~ i -phenylmethanes are 3, 3 '-di- and 3, 3 ', 5, 5 ' -tetra-methyl-, 3, 3 ' -di- and 3, 3 ', 5, 5 ' -tetraethyl- and 3, 3 ~ -di- and 3, 3 ', 5, 5 ' -tetra-n-propyl-4, 4 '--diamino-diphenylmethane .
Preference is given to ~liAm~nn~lirh~nylmethanes of the formula H 2~H 2 ~NH 2 R4 R~
where R~, R5, R6 and R7 nre iri~ntir~l or different and are methyl, ethyl, propyl, isopropyl, sec-butyl or tert-butyl, but at least one must be isopropyl or sec-butyl. The 4,4~ min~ rh~nylmethanes may also be used in ~ mixture with isomer~ of the f- 1 Af:-R~H2 ~NH2 and/or ~ H2~R6 where R~, R5, RE and R7 are as defined above.
Preference is given to 3,5-dimethyl-3~,5~-di-isopropyl- and 3, 3 ~, 5, 5 ' -tetraisopropyl-4, 4 ' -diamino-diphenylmethane . The ri ~ Am ~ n r~l i r~ ~nylmethanes may be employed individually or in the form of mixture~.
The chain -Yt~n~rS and/or crosslinking agents (c) mentioned m~y be used individually or ns mixtures of identical or different types of compound.
If used, the chain extender~, crosslinking agents or mixture~ thereof are -Yre~ ntly employed in ~mounts of from 2 to 609c by weight, preferably from 8 to 5096 by weight, in particular from 10 to 409~ by weight, based on the weight Of ~ _- (b) and (c).
d) The blowing agent (d) used according to the - 18 ~ 204~192 invention i8 a tertiary alcohol (di) or E~r~ff~rAhly a mixture of at least one tertiary ~lcohol (di) and water ( dii ) .
Suitable tertiary alcohols are those of the formula OH
where R~ i5 an aliphatic group containing at least one llydluy n atom bonded to the carbon attached directly to the carbinol group, while R~ and R10 are org2nic groups, eg. aromatic, cycln~ h~tic or preferably Al ~rh~t~ groups. The aliphatic groups ~Yro~7iFntly have from 1 to 6 carbon atoms, preferably 1 or 2 carbon atoms.
Examples of suitable tertiary alcohols are 2-ethyl-2-butanol, 2-ethyl-2-pentanol, 2-methyl-2-pentanol, 3-methyl-3-hexanol, 4-methyl-4-heptznol, 4-propyl-4-heptanol, 4-ethyl-4-heptanol, 2, 3-dimethyl-3-butano~, 2, 3-dimethyl-3-pentanol, 2, 3, 4-trimethyl-3-pentanol, 3-ethyl-2, 4-dimethyl-3-pentanol, 3-iso-propyl-2, 4-dimethyl-3-pentanol, 3-isopropyl-2, 4-dimethyl-3-pentanol and preferably tertiary amyl alcohol, in particular tertiary butyl alcohol. The tertiary ~ nhnl~ may be employed individually or in the form of mixtures of two or more tertiary alcohols.
Particularly successful and therefore preferred blowing agents (d) are mi~ctures comprising di) at least one tertiary alcohol and dii) water.
Since the water reacts with the organic, modified or unmodified polyisocyanate (a) to form carbon dioxide and urea groups, this reaction simul-taneously affects the compressive strength of the cellular moldings.

(1 ) lg 2~4~1~2 The tertiary alcohol ( di ) or the mixture thereof is -Yp~ ntly used in ~n amount of from 0 . 5 to 2096 by weight, preferably from 0.7 to 1096 by weight, in particular from 1 to 59~ by weight, baxed on the total weight of ~ Ls ( a ) to t c ) . The amount of blowing gas formed from the tertiary alcohol and available for foaming is usually less than 50 percent by volume, preferably fron~ 10 to 30 percent by volume, of the amount of gas which can be calculated theoretically.
Since the amount of wzter present as a by-product in the polyester-polyol~ and in particular polyether-polyols preferably used as the high-molecular-weight compound (b) is usually sufficient, there is frequently no need for any separate addition of water when a blowing agent mixture of at least one terti2ry alcohol and water is used. Elowever, if water must be additionally inCGL~ULC~ted into the formula-tion, it is t~Yp~ Pntly used in an amount of from 0.05 to 2% by weight, preferably from 0.09 to 196 by weight, based on the weight of _ Ls (a) to (c).
e ) The catalysts ( e ) used to prepared the cellu-lar plastics by the polyisocyanate polyaddition process are, in particular, r ~ ~u~-ds which greatly Ar~ ate the reaction of the hydroxyl-containing compounds of _ ~ (b) and, if used, (c) with the organic, ' i f i~d or , ' i f i e~ polyisocyanate ( a ) .
Suitable . ul.ds are organometallic compounds, preferably organotin - ~u-~ds, such as tin(I}) salts of organic carboxylic acids, eg. tin(II) acetate, tin(II) octanoate, tin(II) ethylh~Y~nr~ate and tin(II) laurate, ~nd dialkyltin ( IV) salts of organic carboxy-lic acids, eg. dibutyltin diacetnte, dibutyltin dilaurate, dibutyltin maleate nnd dioctyltin diace-tate. The orgnnometallic _ '- are employed nlone or, preferably, in co_bination with highly basic amines, for example Amir1int~st such as 2,3-dimethyl-20 2~5192 3, 4, 5, 6-tetrahydropyrimidine, tertiary amines, such as triethylamine, tributylamine, dimethylbenzylamine, N-methyl-, N-ethyl-, N-cyclohexylmorpholine, N,N,N' ,N'-tetramethylethylen~i; Am; n~, N,N,N' ,N' -tetramethylbu-tAnf~rl;.qmine and -hpyAn~ m;ne, pentamethyldiethylene-triamine, tetramethyldiaminoethyl ether, bis(dimethyl-aminopropyl ) urea, dimethylpiperazine, 1, 2-dimethylimi-dazole, 1 -azabicyclo [ 3 . 3 . 0 ] octane and, pref erably, 1, 4 -diazabicyclo [ 2 . 2 . 2 ] octane and alkanolamine compounds such as triethanolamine, triisopropanolamine, N-methyl-and N-ethyldiethanolamine and dimethylethanolamine.
Suitable catalyst6, in particular if a relatively large excess of polyisocyanate is used, are tris(dialkylAm;nnAlkyl)-s-hexahydrotriazines, preferably tris ( N, N-dimethylaminopropyl ) -s-hexahydrotriazine, tetraalkylammonium hydroxides, such as tetra-methylammonium hydroxide, alkali metal hydroxides, such as sodium hydroxide, and alkali metal alkoxides, such as sodium methoxide and potassium i~,u~uLu~u~ide, and alkali metal salts of long-chain fatty acids having from 10 to 2 o carbon atoms and possibly containing lateral OH
groups. From 0.001 to 5% by weight, in particular from O . 05 to 296 by weight of catalyst or catalyst combination is pref erably used, based on the weight of component (b) .
f ) It is also possible to add, if desired, assistants and/or additives (f ) to the reaction mixture for the preparation of the cRlllllAr plastics by the polyisocyanate polyaddition process. Specific examples are surfactants, foam stabilizers, cell regulators, release agents, fi1lers, dyes, pigments, f1ame~roofing agents, hydrolysis-protection agents, and fungistatic and bacteriostatic substances.
Examples of suitable surfactants are compounds which serve to support homogenization of the starting materials and may also regulate the cell structure.

- ~ 2045192 --specific ~Y~mrl~s are emulsifiers, such as the sodium salts of cnstor oil sulfates, or of fatty acids, ~nd the ~alts of fatty acids with amines, for example diethylamine oleate, diethanolamine stearate and diethanolamine ricinoleate, salts of sulfonic acids, eg. alkali metal salts or ~ n 8alts of dodecyl-benzene- or dinaphthylmethAnP~ ulfonic acid and ricinoleic acld; foam stabilizers, such as siloxane-oxyalkylene copolymers and other organopolysil-~Y~nf~c, oxyethylated alkylphenols, oxyethylated fatty Alrohr~ paraffin oils, castor oil esters, ricinoleic acid esters, Turkey red oil and yluun~,uL oil, and cell regulators, such as paraffins, fatty Alcnhnlc and dimethylpolysi lOYAn~C. Suitable c _ '- for improv-ing the emulsification action, the cell ~sL~ u- Lu~ :
and/or stabilizing the foam are furt~ ol 1; - ic acrylates containing polyoxyalkylene and f luoro21kane radicals as side groups. The surfactants are usually used in amounts of from 0.01 to 5 parts by weight, based on 100 parts by weight of _ _ ~ (b).
Specif ic examples of suitable release agents are products of the reaction of fatty acid esters with polyisocyanates, salts made from amino-cont Ai nin~
polys~ yAn~c and fatty acids, salts made from satur-ated or unsaturated (cyclo)aliphatic carboxylic acids having at least 8 carbon atoms and tertiary amines, and, in particular, int~rn~l release agents, eg.
carboxylic acid esters and~or cA~h~YATnir~s~ prepared by est~-rl f i cation or amidation of a mixture of mon-tanic acid and at least one aliphatic carboxylic acid having at least 10 carbon atoms with at least difunc-tional alkanolamines, polyols and/or polyamines having molecular weights of from 60 to 400 (EP-A-153 63g), mixtures of organic amines, metal salts of stearic ncid and organic mono- and/or ~ -h~Yylic acids or anhydrides thereof (DE-A-3 607 447) or mixtures of an imino _ _-L ', the metal salt of a carboYylic acid -22 ~ 0451~2 and, if desired, a carboxylic acid (US 4,764,537).
Por the ~UL~OSe8 of the invention, fillers, in particular re I n f (~r i n~ f illers, are conv~nt ionA l organic md ~norganic fillers, r~infnrrln~ agents, weighting agents, ~gents for improving the abrasion behavior in paints, coating ~gents, etc . Specif ic e~amples are inorganic f illers, such as silicate m ~nprA1c~ for Qxample phyll nSi1ir;3 tes, such as antigorite, ~erpentine, hnrnhlPn~c, ~mrh;hQlF-chrysotile, and talc; metal oxides, such 25 kaolin, aluminum oxides, titanium oxides and iron oxides, metal 6alts, such as chalk, baryte and inorganic pi _ ' R, such as cadmium sulfide, zinc sulfide and glass, ~nter alia. Preference is given to kaolin (china clay), aluminum silicate and coprecipitates of barium sulfate and aluminum silicate, and natural and ~ynthetic fibrous minerals, such a~ wollastonite, metal fibers and in particular glass fibers of various lengths, which may or may not be sized. Ex2mples of suit2ble organic fillers are carbon black, l~min~, colophony, cyclop~ t~ nyl resins and graft polymers, and celllllnse fibers, polyamide fibers, polyacrylonit-rile fibers, poly--urethane fibers and polyester fibers based on aromatic and/or aliphatic rl 1 r~ ~rhnxylic Acid esters, and in particular carbon fibers.
The ~ nnrg~n i o and organic f illers may be used individually or as mixtures and are advantageously il-LL.-lu- ~=d into the reaction mixture in amounts of from 0.5 to 509~ by weight, preferably from 1 to 404 by weight, based on the weight of ~ t~ (a) to (c), but the content of mats, - _V~ 8 and woven materials made from natural and synthetic fibers m~y reach values of up to 804 by weight.
Ex2mples of suitable fl~ ~,, uofing agents are tricresyl phosphate, tris-2-chloroethyl phosphate, tris-chlo,v~L.,~yl phosphate and tris-2, 3~ yl phosphate .

- 23 _ 204~92 ~n addition to the aLu~ Lioned halogen-substituted phosphates, it is ~lso possible to use inorganic f 1 l , vo~ing agents, such c~ red pho~-phorus, ~ mi oxide hydrate, antimony tr~n~ire, arsenic oxide, ~llm polyphosphate and calcium sulfate, or cyanuric acid derivatives, eg. -lrnnine-, or mixtures of two or more fl: ,_ ~fing agents, eg.
~rmonium polyphosphate and -l~m~n~ and also, if desired, starch, eg. corn starch, in order to flame-proof the polyisocyanate polyaddition products. In general, it has proven ~>e~ nt to use from 5 to 50 parts by weight, preferably from 5 to 25 parts by weight, of said fli ~ ~Dofing agents per 100 parts by weight of _ ~ - ~b ) .
Further detail~ on the other conventlonal ~ssistants and additives mentioned above can be obtained from the sp~ri~l ~Rt literature, for example from the by J.H. Saunders and lt.C. Frisch, High Polymers, Volume XVI, Polyurethanes, Parts 1 and 2, Interscience p~lhl~h~r~ 1962 and 1964 respectively, or ~unststoff-~n~hl~rh, Polyurethane, Volume VII, Hanser-Verlag, ~unich, Vienna, 1st and 2nd Editions, lg66 and 1983 .
To prepare the cellular urea- and/or preferably urethane-containing plastics, the organic polyisocyanatQ
(a), the high-molecular-weight c ~ _ ' containing at least two renctive ~ Lvy-:n atoms (b) and, if used, the chain ~ nri~'r and~or crosslinking agent (c) are reacted in such amounts that the equivalence ratio between the NC0 qroups of the polyisocyanate (a) and the total number of reactive 1~ o~ toms of ~ - (b) and, if used, (c) is from 1~0.85 to 1.25, preferably from 1:0.95 to 1.15. If the cellular plastics contain, at least parti-ally, iso- ya~ t~ group~ in bound form, a ratio between the NC0 groups of the polyisocyanate (a) and the total nu_ber of reactive l,y l v~ atoms of: , - (b) and, if used, (c) of from 1.5 to 20sl, preferably from 1.5 to - 24 ~5192 8:1, is usually used.
The c~ Ar plastics comprising polyisocyanate polyaddition products, preferably cellular elastomers or in particular foams, are advAntAgeo~ly rrerAro~ by the ~i one-shot process, for example llsing reaction ~n~ection molding, high-pressure molding or low-pressure molding in open or closed molds, for example metallic molds, eg.
made of ~ n~ cast iron or steel. It has proven partic~lAr~y advantageous to use the two-_ ~nt process and to combine _ _ - c (b), (d), (e) and, if used, (c) and (f ) ln c L (A) and to use, as _ _ ~ (B), the organic polyisocyanate, -d1fied polyisocyanate (a) or a mixture of said polyisocyanates ~md~ if desired, a blowing agent (d).
The starting _ Ls are mixed at from 15 to 90-C, preferably from 20 to 35-C, and introduced into the open mold or, if desired under .,u~e~ heric p- ~:s:,u ~:, into the closed mold. As stated above, the mixing can be carried out by means of a --h~ni~-Al stirrer or stirring screw or under high pressure by the count6L~ u ~ L
in~ection method. The mold t~ ~Lul~ is o rodi~ntly from 20 to 90-C, preferably from 30 to 60-C, in particu-lar from 45 to 50-C.
In a preferred ~ L, the cellular plastics, in particular col 3 ul Ar elastomers, are prepared using reaction in~ection molding in a closed mold and the moldings are produced with a compacted peripheral zone and a ce7 1~ r core in a closed mold with compaction to a degree of from 1. 5 to 8 . 5, preferably from 2 to 6 .
The c~ l Ar elastomers prepared by the process ~cordi nq to the invention have approximate densities of from 0.70 to 1.2 g~cm', preferably from 0.8 to 1.0 g/cm3, it being possible for the density of filler_cnntJ~ini products to achieve higher values, for example of up to 1.4 g~cm3 or more. Moldings made from cell~lAr elastomers of this type are used in the automotive industry, for example as o~tornAl p_rts, eg. rear spoilers ~nd fenders, - 25 2Q ~5 19 ~
and ~nt~rnAl pf~nPl in~ and as shoe soles.
The soft-elastic, semihard and hard foams prepared by the process according to the invention and the c~ ding 8L u.Lu.~l foams have n density of from O . 02 to 0 . 9 g/cm~, the densities of the foams prPf~r~hly being from 0.025 to 0.24 g/cmJ, in particular from 0.03 to 0.1 g/cm~, the overall densities of the ~emihard and hard ~L~ u~Lul al foams preferably being from 0.2 to 0.9 g/cm3, in particular from 0.35 to 0.8 g/cm3, and the overall densities of the soft-elastic structural foams preferahly being from 0.08 to 0.7 g/cm3, in particular from 0.12 to 0.6 g/cm3. The foams and .,L u~Lu~Gl foams are used, for esample, in the vehicle industry, eg.
automotive, nircraft and ~hirh~ in~ industries, for example for armrests, headrests or safety covers, in the furniture and sports article industries as, for example, C"~:h irn~n~ materials, casing parts, eg. for office and domestic equipment, window frames, skiboot inners, ski cores inter alia. They are particularly suitable as ~n insulation material in the construction and refrigerator ~ectors .
E2U~MPLE 1 C _ L A:
A mixture was prepared at room temperature from the following substances s 49 parts by weight of a polyether-polyol having an OH
number of 480, prepared by poly-~ddition of 1,2-propylene oxide on to ethyl ~ nc ~iI Ym~ n~
parts by weight of a polyether-polyol having an O~
nuD~ber of 56, prepared by poly-addition of 1,2-propylene oxide on to ethylene glycol, 8 parts by weight of glycerol, 2 parts by weight of a 8il ;rrnp oil (Tegostab B 8418 from Gol ~ ~r ~ ~t ), 0.75 part by weight of methylS"~ cle, l t l) - 26 ~ 4~92 0.2 part by weiqht of water and 5 parts by weight of tert-butanol.
C B:
A ~ixture of diphenylmethane dii~socyanates and polyphenyl-polymethylene polyisocyanates cont~ ~ n i ng 319~
by weight of NC0 ~Lupranat M 20 S from BASP Aktien-g~Qe-l 1 R--h~ft) .
100 parts by weight of - -nt A and 118 parts by weight of L B were mixed at 23-C with vigorous ~tirring. Some of the foamable reaction mixture was transferred into an open mold and allowed to expand. The freely foamed density of the resultant foam was 0.15 g~cm~.
Another portion of the fo -hle reaction mixture was introduced into one end of a mold, t~ atted at 60-C, compris$ng surface-~r~Yirli~ed Alllminll~l and measur-ing 100 x 30 x 1 cm, in such an amount that, nfter expansion and curing in the closed mold, a hard structu-ral foam sheet having an over~ll density of 0.6 g/cm3 was produced.
The ~h~rkn~ss, detDrmin-~d by microscopy, of the essentially compact p~'rirhDrAl zone was from 1. 3 to 1.5 mm, and the ~;hrinl~qe of the molding after cooling was from 0.4 to 0.59~.
The Shore D hardness was measured every 10 cm along the flow path. The following values were deter-mined:
Fls~w distance tcm] 10 20 30 40 50 60 70 80 90 100 Shore D h~8ess 70 70 69 71 70 70 70 69 68 69 This gives a mean of 70 and a vAr~Ation coc~ffjri~nt of 1.296 ~variation coefficient ~ standard deviation divided by the mean, as a me~sure of the lln~f~rmity of the flow part ) .
COMPARATIVE ~NPLE I
C ^nt A: As in Example 1, but with the 0 . 2 part by ~ - 27 - ~ 2"~192 .~, weight of water replaced by 0.~5 part by weight, and the addition of tertiary butanol being omitted.
C _ ~ -nt B s 2s in Ex~mple The molding was likewise produced by a method similar to that of Example 1.
The molding had 2 compacted peripheral zone in a ~hlrknD~s of only 0.6 to 0.8 mm, while the ~5hrinl~e ~ncreased to 0 . 896 .
The following Shore D hz~ ss~s were measured on the molding over the length of the flow p~th:
Flow distarce [cm] 10 20 30 40 50 60 70 80 90 100 Sh~e D hardness 69 67 67 66 66 65 65 65 64 64 The mean Shore D hardness was 66, and the varin-tion coeffir~"t- was 2.35. Due to the worse formation of the p~irhF-~al zone, the h2rdness of the molding was not only substantially lower, but the uniformity over the entire flow path was worse by a factor of almost 2.
EZAI~LE 2 C _ ~lt As A mixture was prepared at room t _ ~ILu~.:
comprising:
28 parts by weight of a polyether-polyol having an OH
n~smber of 550, prepared by poly-addition of 1,2-propylene oxide on to trimethylolpropane, 17 parts by weight of polyether-polyol having an OH
number of 400, prepared by poly-addition of 1, 2-propylene oxide on to glycerol, 23 parts by weight of a polyu,.y~ ylene (759~ by weight)-polyoxyethylene (2596 by weight)-polyol having an OH number of 35, prepared by polyadditon of 1,2-propylene oxide on ~o glycerol and sllhs~51u~nt polyaddition of -28 - 2~4~192 ethylene o~cide on to the glycerol-1, 2 -propylene o~cide adduct, 15 parts by weight of glycerol 0.3 part by weight of water, 5 6 parts by weight of tert-butanol, 2.4 parts by weight of a silicone oil (Tegostab B 8418 from r,n~ rhmirit), 1.5 pnrts by weight of N,~l-dimethylcycloheYylamine 0.8 parts by weight of methyl~m;~7~7~ and 6 parts by weight of t~ hloroethyl phosphate C B: as in l~xample 1.
100 part-~ by weight of _ ~ A and 133 parts by weight of L B were m~xed at 23-C with vigorous Etirring, and foamed by a method similar to that of E~cample 1 with compactlon using an open and a closed mold .
The density of the freely foamed molding was 0.13 g/cm3.
~rhe hard bLlu~Lu-cll foam sheet produced had an overall density of 0.5 g/cm3, a Shore D hardness of 72 and a v~ri~t~nn coefficient of the Shore D hArrln-~ss along the flow path of 1.1%.
CO!~ARA~IVE EXA~LE II
q~he p-ucc lu _ was bimilar to that of EYample 2, but the mixture of 0 . 3 parts by weight of water and 6 parts by weight of tertiary butanol in _ - L A was replaced by only 0 . 9 parts by weight of water. The resultant molding had an overall density of 0 . 6 g/l, a mean Shore D hardness of 67 and a variation coefficient of the Shore D hardness along the flow path of 3.0%.

C ~ A
A mixture was prepared at room temperature compris ing: -35 42 parts by weight of a polyu.. y~,.u~ylene t75% by weight)-polyoxyethylene (25% by - 29 ~ ~045 192 ~weight)-polyol havlng an OH nu_ber of 23, prepared by polyaddition of 1,2-propylene oxide on to ethylene glycol and ~ub~e~uenL polyaddition of ethylene oxide on to the Qthylene glycol-1,2-propylene oxide ~dduct, 40 parts by weight of a polyuAy~L~ylene (~5% by weight)-polyoxyethylene 1259~ by -weight)-polyol having an OEI number of 35, prepared by polyadditon of 1,2-propylene oxide on to glycerol and subsequent polyaddition of ethylene oxide on to the glycerol-1, 2-propylene oxide adduct, parts by weight of Qthylene glycol 0.3 part by weight of triethylen~ min~-0.2 part by weight of water parts by weight of tert-butanol.
C -nt Bs Polyisocyanate mixture c~nt~; n i ng urethane groups and 28% by weight of NCO, prepared by partial reaction of a mixture of diphenylmethane diisocyanates and poly-phenyl-polymethylene polyisocyanates containing 319~ by weight of NCO with dipropylene glycol.
100 parts by weight of _ _ t A and 48 parts by wQight of ~ _ - B were mixed vigorously, and the reaction mi~cture wa~ tr nsferred into an All~m~n--m mold measuring 20 ~ 20 x 1 cm and ~ - _Latted at 50-C, in ~uch an amount that a molding having an overall den~ity of 0.35 g/cm~ was ~ duced.
I~fter the reaction mi~ ture had been ~ n~d and allowed to cure in the clo~ed mold, a flexible .~L~u~LuL~ll foam Kheet having a Shore A hardness of 37, a well-formed compact p~r~rh~-r~l ~one and a e~mooth, pore-free ~urface was obtained.

~ t ,,. , _ 30! ` 2~4~1~2 coMp~R~rrIvE 3~:XANPL~ III
The ~ ~,cedu~e was similar to that of l~ample 3, but O.S part by weight of water was ~Ised in , L A, ~nd the addLtion of the tertiary butanol was omitted.
The molding ~ ,du~ed had ~ Shore A hardness of 29 and a porous peripheral zone having A pore-c-~ntAi ffkin .

Claims (10)

1. A process for the production of integral skin moldings having a compacted peripheral zone and a cellular core comprised of a polyurethane and/or polyisocyanurate polymer, comprising reacting:
a) an organic polyisocyanate with b) at least one high-molecular-weight compound containing at least two reactive hydrogen atoms, in the presence of d) an acid free blowing agent selected from the group consisting of:
di) at least one tertiary alcohol having one isocyanate reactive hydrogen; and dii) at least one tertiary alcohol in admixture with water;
e) a catalyst in an amount effective to promote urethane and/or isocyanurates linkages, in a closed mold with compaction.

2. A process as claimed in claim 1, wherein the reaction is carried out in the additional presence of:
c) a low-molecular-weight chain extender and/or cross-linking agent.

3. A process as claimed in claim 1 or 2, wherein the blowing agent (d) that is used consists of at least one tertiary alcohol in admixture with water.

4. A process as claimed in claim 1 or 2, wherein the blowing agent (d) that is used comprises from 0.5 to 20%
by weight, based on the total weight of components (a), (b) and (c) whenever present, of at least one tertiary alcohol.

5. A process as claimed in claim 3, wherein the blowing agent (d) that is used is a mixture comprising:
di) from 0.5 to 20% by weight of at least one tertiary alcohol; and dii) from 0.05 to 2% by weight of water, said percentages by weight being based on the total weight of components (a), (b) and (c) whenever present.

6. A process as claimed in claim 1 or 2, wherein the at least one tertiary alcohol of the blowing agent is tertiary butanol.

7. A process as claimed in claim 1, 2 or 5, wherein the reaction is carried out in the closed mold with compaction to a degree of from 2 to 6.

8. A process as claimed in claim 1, 2 or 5, wherein the organic polyisocyanate (a) that is used is a mixture of a diphenylmethane diisocyanate and a polyphenyl-polymethylne polyisocyanate having a diphenylmethane diisocyanate isomer content of from 30 to 80% by weight.

9. A process as claimed in claim 1, 2 or 5, wherein the high-molecular-weight compound (b) that is used is a polyether-polyol, polyester-polyol made from an alkanedicarboxylic acid and a polyhydric alcohol, a polyester-amide, a hydroxyl-containing polyacetal and/or a hydroxyl-containing aliphatic polycarbonate.

10. A process as claimed in claim 1, 2 or 5, wherein the high-molecular-weight compound (b) that is used is at least one polyether-polyol having a functionality of from 3 to 8 and a molecular weight of from 400 to 3200.