EP0000389A1 - Process for the preparation of polyurethane resins - Google Patents

Abstract

Process for the production of optionally cellular polyurethane plastics by reacting a) polyisocyanates with b) compounds having at least 2 hydrogen atoms which are reactive toward isocyanates, in the presence of c) tertiary amines as catalysts, optionally with the use of d) blowing agents, stabilizers and other additives known per se , characterized in that as catalysts, optionally in a mixture with known tertiary amine catalysts, compounds are used which, in addition to at least 2 tertiary nitrogen atoms, contain at least one primary or secondary nitrogen atom.

Description

The present invention relates to a process for the production of polyurethane plastics, preferably foams, using novel catalysts having tertiary nitrogen atoms which are incorporated into the polyurethane and at the same time act as aging and light stabilizers.

Polyurethane foams with a wide variety of physical properties are made by the known isocyanate polyaddition process from compounds with several active hydrogen atoms, in particular compounds containing hydroxyl and / or carboxyl groups, and polyisocyanates, with the use of water and / or blowing agents and, if appropriate, catalysts, emulsifiers and other additives, has long been produced on an industrial scale (Angew. Chem. A, 59 (1948), p. 257). With a suitable choice of components, either elastic or rigid foams or all products lying between these extremes are obtained.

Polyurethane foams are preferably produced from liquid starting components, the starting materials to be reacted with one another either in one step process are mixed together or an NCO group-containing pre-adduct is first prepared from a polyol and an excess of polyisocyanate, which is then foamed, for example by reaction with water.

Tertiary amines have proven themselves as catalysts in the production of polyurethane foams primarily because they accelerate both the reaction between hydroxyl or carboxyl groups and NCO groups (urethane reaction) and the reaction between water and isocyanates (blowing reaction), also in the case of One-step process ("one-shot") the speeds of the two reactions running side by side can be coordinated.

In addition to the reactions already mentioned, additional crosslinking reactions take place during the foaming process, with the formation of allophanate, biuret and cyanurate structures.

In view of this large number of reactions, it is necessary to choose the catalyst in such a way that, on the one hand, the synchronous course of the reactions is ensured and, on the other hand, the catalyst is not fixed too early by incorporation into the foam or later accelerates the hydrolytic degradation of the finished foam. This problem has not yet been fully satisfactorily resolved. In addition, the unpleasant smell of many tertiary amines used in practice is disadvantageous. In addition, polyurethane foams tend to be present in the presence of tech The most commonly used amine catalysts such as Dabco or bis (dialkylaminoalkyl) ethers (DOS 1 804 361 and US Pat. No. 3,330,782) on their own or also laminated with colored plastic films (for example PVC films) for yellowing or discoloration and blackening thermal load or exposure to light. Is particularly disturbing case, the blackening of colored plastic, _w it ie to cladding of polyurethane foams technically eg car seats, refrigerators and electrical appliances are used. These adverse effects block the polyurethane foams and polyurethane plastics in many other possible areas of application.

Surprisingly, catalysts have now been found which, on their own or in a mixture with known amine catalysts, prevent discoloration of foam-backed plastic films (e.g. PVC films) under thermal stress and / or exposure to light, as well as aging effects in the case of free-foamed polyurethane plastics.

• (a) Polyisocyanaten mit
• (b) Verbindungen mit mindestens 2 gegenüber Isocyanaten reaktionsfähigen Wasserstoffatomen, in Gegenwart von
• (c) tertiären Aminen als Katalysatoren, gegebenenfalls unter Mitverwendung von
• (d) Treibmitteln, Stabilisatoren und weiteren an sich bekannten Zusatzstoffen,
  welches dadurch gekennzeichnet ist, daß als Komponente (c) (A) Verbindungen der allgemeinen Formel
  
  und/oder
  
  und/oder
  
  und/oder
  
  gegebenenfalls im Gemisch mit (B) anderen tertiären Aminen als Co-Katalysator, eingesetzt werden, wobei
  • die Reste _R unabhängig voneinander gegebenenfalls verzweigte Alkylgruppen mit 1 - 4 C-Atomen, vorzugsweise Methylgruppen,darstellen,
  • die Zahlen n unabhängig voneinander für 2 oder 3, vorzugsweise für 3,
  • die Zahlen m unabhängig voneinander für 2 oder 3, vorzugsweise für 2, und
  • k für eine ganze Zahl zwischen 1 und 5 stehen.

The present invention relates to a process for the production of optionally cellular polyurethane plastics by reacting

• (a) Polyisocyanates with
• (b) Compounds with at least 2 isocyanate-reactive hydrogen atoms, in the presence of
• (c) tertiary amines as catalysts, optionally with the use of
• (d) blowing agents, stabilizers and other additives known per se,
  which is characterized in that as component (c) (A) compounds of the general formula
  
  and or
  
  and or
  
  and or
  
  optionally in a mixture with (B) other tertiary amines as cocatalyst, are used, wherein
  • the radicals _R independently of one another are optionally branched alkyl groups having 1 to 4 carbon atoms, preferably methyl groups,
  • the numbers n independently of one another for 2 or 3, preferably for 3,
  • the numbers m independently of one another for 2 or 3, preferably for 2, and
  • k represents an integer between 1 and 5.

According to the invention, preferred catalysts (A) are compounds of the general formulas (1) and (2).

The catalysts characterized by the general formulas (1) to (4) have a special position compared to the tertiary amines previously used due to their stabilizing action against thermal and photochemical aging. This is probably due to the fact that despite their content of active hydrogen atoms - due to steric hindrance - they are only very slowly incorporated into the polyurethane during the foaming process. As a result, they can surprisingly develop their stabilizing effect at the phase interfaces.

und

wobei R und n die oben angegebene Bedeutung haben.In the process according to the invention, in addition to the compounds (A) of the general formulas (1) to (4), amine catalysts (B) known per se in an amount of 3 to 97 mol%, preferably 10 to 90 mol%, particularly preferably 30 up to 70 mol%, based on the total amount of catalyst, can also be used, for example tertiary amines containing ether groups according to US Pat. No. 3,330,782, DAS 1 030 558 or DOS 1 804 361 or the ether-free catalysts from DOS having at least 4 tertiary nitrogen atoms 2,624,527 and DOS 2,624,528. However, preferred co-catalysts (B) according to the invention are compounds which, in addition to at least one tertiary nitrogen atom, contain at least one amide group, in particular one formamide group. Such acylated amines are described in detail in DOS 2 523 633. According to the invention, the formylation products of the compounds (A) of the general formulas (1) to (4) and the compounds are particularly preferred in this context

and

where R and n have the meaning given above.

Examples of catalysts or co-catalysts to be used according to the invention are the following tertiary amines:

The catalysts to be used according to the invention can be prepared in a manner known per se, for example in DAS 1 154 269, DOS 2 523 633 and in "Die Angewandte Makromolekulare Chemie" 34, pp. 111-132 (1973), and from F Möller in Houben-Weyl, XI / 2 (pp. 27-29).

According to the invention, a total of 0.01-5% by weight, preferably 0.1-3% by weight, based on the entire reaction mixture, of catalyst is generally used.

As the starting components to be used according to the invention, aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates come into consideration, as described, for. B. by W. Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136, for example ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, cyclobutane-1, 3-diisocyanate, cyclohexane-1,3- and -1,4-diiaocyanate and any mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (DAS 1 202 785, American patent specification 3 401 190), 2,4- and 2,6-hexahydrotoluiene diisocyanate and any mixtures of these isomers, hexahydro-1,3- and / or 1,4-phenylene diisocyanate, perhydro-2,4'- and / or -4, 4'-diphenylmethane diisocyanate, 1,3- and 1,4-phenylene diisocyanate, 2,4- and 2,6-tolylene diisocyanate as well as any mixtures of these isomers, diphenylmethane-2,4'- and / or -4,4'- diisocyanate, naphthylene-1,5-diisocyanate, triphenylmethane-4,4 ', 4 "-triisocyanate, polyphenyl-polymethylene-polyisocyanates as obtained by aniline-formaldehyde condensation and subsequent phosgenation and, for example, in the b Ritische patent specifications 874 430 and 848 671 are described, m- and p-isocyanatophenylsulfonyl-isocyanates according to the American patent specification 3 454 606, perchlorinated aryl polyisocyanates, as described for example in the German patent specification 1 157 601 (American patent specification 3,277,138), carbodiimide groups polyisocyanates comprising, as described in German Patent 1,092,007 (US Pat. No. 3,152,162), diisocyanates as described in American Patent 3,492,330, polyisocyanates containing allophanate groups, as described, for example, in British Patent 994,890, Belgian patent 761 626 and published Dutch patent application 7 102 524, which contain isocyanurate groups Polyisocyanates as described, for example, in US Pat. No. 3,001,973, in German Patents 1,022,789, 1,222,067 and 1,027,394 and in German Laid-Open Publications 1,929,034 and 2,004,048, polyisocyanates containing urethane groups, as described, for example are described in Belgian patent specification 752 261 or in American patent specification 3 394 164, polyisocyanates containing acylated urea groups according to German patent specification 1 230 778, polyisocyanates containing biuret groups, as described, for example, in German patent specification 1 ₁ 01 394 (American patent specifications 3 124 605 and 3,201,372) and in British Patent 889,050, polyisocyanates prepared by telomerization reactions, such as are described, for example, in American Patent 3,654,106, and polyisocyanates containing ester groups, such as, for example, in British Patents 965,474 and 1,072 956, in the American Patentsch rift 3 567 763 and in German Patent 1,231,688, reaction products of the above isocyanates with acetals and according to German Patent 1,072,385 and polyisocyanates containing polymeric fatty acid residues according to American Patent 3,455,883.

It is also possible to use the distillation residues obtained in the industrial production of isocyanate and containing isocyanate groups, optionally dissolved in one or more of the aforementioned polyisocyanates. It is also possible to use any mixtures of the aforementioned polyisocyanates.

The technically easily accessible polyisocyanates, e.g. 2,4- and 2,6-tolylene diisocyanate as well as any mixtures of these isomers ("TDI"), polyphenyl-polymethylene polyisocyanates, such as those produced by aniline-formaldehyde condensation and subsequent phosgenation ("crude MDI") and carbodiimide groups, Urethane groups, allophanate groups, isocyanurate groups, urea groups and polyisocyanates containing biuret groups ("modified polyisocyanates").

Starting components to be used according to the invention are furthermore compounds having at least two isocyanate-reactive hydrogen atoms with a molecular weight of generally 400-10,000. These include compounds containing amino groups, thiol groups or carboxyl groups, preferably polyhydroxyl compounds, in particular two to eight compounds containing hydroxyl groups, especially those of Molecular weight 800 to 10,000, preferably 1000 to 6000, e.g. at least two, usually 2 to 8, but preferably 2 to 4, hydroxyl-containing polyesters, polyethers, polythioethers, polyacetals, polycarbonates and polyesteramides, as are known per se for the production of homogeneous and cellular polyurethanes.

The hydroxyl group-containing polyesters are e.g. Reaction products of polyhydric, preferably dihydric and optionally additionally trihydric alcohols with polyhydric, preferably dihydric, carboxylic acids. Instead of the free polycarboxylic acids, the corresponding polycarboxylic anhydrides or corresponding polycarboxylic esters of lower alcohols or mixtures thereof can also be used to produce the polyesters. The polycarboxylic acids can be aliphatic, cycloaliphatic, aromatic and / or heterocyclic in nature and optionally, e.g. by halogen atoms, substituted and / or unsaturated.

mentioned as examples: succinic acid, adipic acid, azelaic acid, phthalic acid, trimellitic anhydride, phthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic endomethylenetetrahydrophthalic, glutaric anhydride, maleic anhydride, Fumärsäure, dimeric and trimeric fatty acids such as oleic acid, optionally mixed with monomeric fatty acids, dimethyl terephthalate and bis-glycol terephthalate. As polyhydric alcohols are e.g. 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, glycerin, trimethylolpropane, hexanetriol- (1,2,6), butanetriol- (1,2,4), trimethylolethane, pentaerythritol , Quinite, mannitol and sorbitol, methylglycoside, also diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycols, dipropylene glycol, polypropylene glycols, dibutylene glycol and polybutylene glycol in question. The polyesters can have a proportion of terminal carboxyl groups. Lactone polyester, e.g. E-caprolactone or hydroxycarboxylic acids, e.g. ω-hydroxycaproic acid can be used.

The at least two, usually two to eight, preferably two to three, hydroxyl groups-containing polyethers which are suitable according to the invention are also of the type known to aich and are, for example, by poly merization of epoxides such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin with themselves, for example in the presence of BF ₃ , or by addition of these epoxides, optionally in a mixture or in succession, to starting components with reactive hydrogen atoms such as water, alcohols, ammonia or Amines, for example ethylene glycol, propylene glycol (1,3) or - (1,2), trimethylolpropane, 4,4'-dihydroxy-diphenylpropane, aniline, ethanolamine or ethylenediamine. Sucrose polyethers, such as are described, for example, in German publications 1 176 358 and 1 064 938, are also suitable according to the invention. In many cases, those polyethers are preferred which predominantly (up to 90% by weight, based on all the OH groups present in the polyether) have primary OH groups. Polyethers modified by vinyl polymers, such as those formed, for example, by polymerizing styrene and acrylonitrile in the presence of polyethers (American patents 3,383,351, 3,304,273, 3,523,093, 3,110,695, German patent 1,152,536), are also suitable Polybutadienes containing OH groups.

Among the polythioethers, the condensation products of thiodiglycol with themselves and / or with other glycols, dicarboxylic acids, formaldehyde, aminocarboxylic acids or amino alcohols should be mentioned in particular. Depending on the co-components, the products are polythio ether, polythio ether ester or polythio ether ester amide.

As polyacetals e.g. the compounds which can be prepared from glycols, such as diethylene glycol, triethylene glycol, 4,4'-dioxethoxydiphenyldimethylmethane, hexanediol and formaldehyde, are suitable. Polyacetals suitable according to the invention can also be prepared by polymerizing cyclic acetals.

Suitable polycarbonates containing hydroxyl groups are those of the type known per se, which e.g. by reacting diols such as propanediol (1,3), butanediol (1,4) and / or hexanediol (1,6), diethylene glycol, triethylene glycol or tetraethylene glycol with diaryl carbonates, e.g. Diphenyl carbonate, or phosgene can be produced.

The polyester amides and polyamides include e.g. the predominantly linear condensates obtained from polyvalent saturated and unsaturated carboxylic acids or their anhydrides and polyvalent saturated and unsaturated amino alcohols, diamines, polyamines and their mixtures.

Polyhydroxyl compounds already containing urethane or urea groups and optionally modified natural polyols such as castor oil, carbohydrates or starch can also be used. Addition products of alkylene oxides on phenol-formaldehyde resins or also on urea-formaldehyde resins can also be used according to the invention.

Representatives of these compounds to be used according to the invention are e.g. in High Polymers, Vol. XVI, "Polyurethanes, Chemistry and Technology", written by Saunders-Frisch, Interscience Publishers, New York, London, Volume I, 1962, pages 32-42 and pages 44-54 and Volume II, 1964, Pages 5-6 and 198-199, as well as in the plastics manual, volume VII, Vieweg-Höchtlen, Carl-Hanser-Verlag, Munich, 1966, e.g. on pages 45-71.

Of course, mixtures of the above-mentioned compounds with at least two isocyanate-reactive hydrogen atoms with a molecular weight of 400-10,000, e.g. Mixtures of polyethers and polyesters can be used.

Compounds with at least two isocyanate-reactive hydrogen atoms with a molecular weight of 32-400 are also suitable as starting components to be used according to the invention, if appropriate in a mixture with the higher molecular weight compounds mentioned. In this case too, this means hydroxyl groups and / or amino groups and / or thiol groups and / or carboxyl groups, preferably compounds having hydroxyl groups and / or amino groups, which serve as chain extenders or crosslinking agents. These compounds generally have 2 to 8 isocyanate-reactive hydrogen atoms, preferably 2 or 3 reactive hydrogen atoms.

Examples of such compounds are: ethylene glycol, (1,2) and - (1,3) propylene glycol, (1,4) and - (2,3) butylene glycol, (1,5) pentanediol, hexanediol (1,6), octanediol- (1,8), neopentyl glycol, 1,4-bishydroxymethyl-cyclohexane, 2-methyl-1,3-propanediol, glycerin, trimethylolpropane, hexanetriol- (1,2,6), trimethylolethane, Pentaerythritol, quinite, mannitol and sorbitol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycols with a molecular weight of up to 400, dipropylene glycol, polypropylene glycols with a molecular weight of up to 400, dibutylene glycol, polybutylene glycols with a molecular weight of up to 400, 4,4'-propylene-dihydroxy hydroquinone, ethanolamine, diethanolamine, triethanolamine, 3-aminopropanol, ethylenediamine, 1,3-diaminopropane, 1-mercapto-3-aminopropane, 4-hydroxy- or aminophthalic acid, succinic acid, adipic acid, hydrazine, N, N ' -Dimethylhydrazine, 4,4'-diaminodiphenylmethane, toluenediamine, methylene-bis-chloroaniline, methylene-bis-anthrani oleic acid ester diaminobenzoic acid ester and the isomeric chlorophenylene diamines.

In this case too, mixtures of different compounds with at least two isocyanate-reactive hydrogen atoms with a molecular weight of 32-400 can be used.

According to the invention, however, polyhydroxyl compounds can also be used in which high molecular weight polyadducts or polycondensates are contained in finely dispersed or dissolved form. Such modified polyhydroxyl compounds are obtained if polyaddition reactions (for example reactions between polyisocyanates and amino-functional compounds) or polycondensation reactions (for example between formaldehyde and phenols and / or amines) are carried out directly in situ in the above-mentioned compounds containing hydroxyl groups. Such methods are described, for example, in German Patent Specifications 1 168 075 and 1 260 142, and German Offenlegungsschriften 2 324 134, 2 423 984, 2 512 385, 2 513 815, .2 550 796, 2 550 797, 2 550 833 and 2 55 ₀ 862. However, it is also possible to mix a finished aqueous polymer dispersion with a polyhydroxyl compound in accordance with US Pat. No. 3,869,413 or German Offenlegungsschrift 2,550,860 and then remove the water from the mixture.

In the modified polyhydroxyl compounds of the above _A rt as a starting component in the polyisocyanate polyaddition arise in many cases polyurethane plastics with substantially improved mechanical properties.

According to the invention, water and / or volatile organic substances can also be used as blowing agents. Acetone, ethyl acetate, halogen-substituted alkanes such as methylene chloride, chloroform, ethylidene chloride, vinylidene chloride, monofluorotrichloromethane, chlorodifluoromethane, dichlorodifluoromethane, butane, hexane, heptane or diethyl ether are also suitable. A blowing effect can also be achieved by adding compounds which decompose at temperatures above room temperature with the elimination of gases, for example nitrogen. Azo compounds such as azoisobutyronitrile can be achieved. Further examples of propellants as well as details on the use of propellants can be found in the Kunststoff-Handbuch, Volume VII, published by Vieweg and Höchtlen, Carl-Hanser-Verlag, Munich 1966, e.g. on pages 108 and 109, 453 to 455 and 507 to 510.

According to the invention, other catalysts known per se can of course also be used, e.g. tertiary amines such as triethylamine, tributylamine, N-methyl-morpholine, N-ethyl-morpholine, N-cocomorpholine, N, N, N ', N'-tetramethyl-ethylenediamine, 1,4-diaza-bicyclo- (2.2 , 2) octane, N-methyl-N'-dimethylaminoethyl-piperazine, N, N-dimethylbenzylamine, bis (N, N-di-ethylaminoethyl) adipate, N, N-diethylbenzylamine, pentamethyldiethylenetriamine, N, N -Dimethylcyclohexylamine, N, N, N ', N'-tetramethyl-1,3-butanediamine, N, N-dimethyl-β-phenylethylamine, 1,2-dimethylimidazole and 2-methylimidazole. Mannich bases known per se from secondary amines such as dimethylamine and aldehydes, preferably formaldehyde, or ketones such as acetone, methyl ethyl ketone or cyclohexanone and phenols such as phenol, nonylphenol or bisphenol are also suitable as additional catalysts.

Tertiary amines which have hydrogen atoms active against isocyanate groups as catalysts are e.g. Triethanolamine, triisopropanolamine, N-methyldiethanolamine, N-ethyl-diethanolamine, N, N-dimethyl-ethanolamine, and their reaction products with alkylene oxides, such as propylene oxide and / or ethylene oxide.

Silaamines with carbon-silicon bonds, such as those e.g. in German Patent 1,229,290 (corresponding to American Patent 3,620,984) are in question, e.g. 2,2,4-trimethyl-2-silamorpholine and 1,3-diethylaminomethyltetramethyl-disiloxane.

Suitable additional catalysts are also nitrogenous bases such as tetraalkylammonium hydroxides, alkali metal hydroxides such as sodium hydroxide, alkali phenolates such as sodium phenolate or alkali metal alcoholates such as sodium methylate. Hexahydrotriazines can also be used as catalysts.

According to the invention, organic metal compounds, in particular organic tin compounds, can also be used as catalysts.

Preferred organic tin compounds are tin (II) salts of carboxylic acids such as tin (II) acetate, tin (II) octoate, tin (II) ethylhexoate and tin (II) laurate and the tin (IV) compounds, For example, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate or dioctyltin diacetate can be considered. Of course, all of the above catalysts can be used as mixtures.

Other representatives of catalysts which may be used according to the invention and details of the activity The catalysts are described in the plastics manual, volume VII, published by Vieweg and Höchtlen, Carl-Hanser-Verlag, Munich 1966, for example on pages 96 to 102.

According to the invention, surface-active additives, such as emulsifiers and foam stabilizers, can also be used.

The emulsifiers are e.g. the sodium salts of castor oil sulfonates or salts of fatty acids with amines such as oleic acid diethylamine or stearic acid diethanolamine. Alkali or ammonium salts of sulfonic acids such as dodecylbenzenesulfonic acid or dinaphthylmethane disulfonic acid or of fatty acids such as ricinoleic acid or of polymeric fatty acids can also be used as surface-active additives.

Polyether siloxanes, especially water-soluble representatives, are particularly suitable as foam stabilizers. These compounds are generally constructed in such a way that a copolymer of ethylene oxide and propylene oxide is linked to a polydimethylsiloxane radical. Such foam stabilizers are e.g. in U.S. Patents 2,834,748, 2,917,480, and 3,629,308.

According to the invention, reaction retarders, e.g. acid-reacting substances such as hydrochloric acid or organic acid halides, furthermore cell regulators of the type known per se such as paraffins or fatty alcohols or dimethylpolysiloxanes as well as pigments or dyes and flame retardants of the type known per se, e.g. Tris-chloroethyl phosphate, tricresyl phosphate or ammonium phosphate and polyphosphate, also stabilizers against aging and weather influences, plasticizers and fungistatic and bacteriostatic substances, and fillers such as barium sulfate, diatomaceous earth, carbon black or sludge chalk are also used.

Further examples of surface-active additives and foam stabilizers to be used according to the invention, as well as cell regulators, reaction retarders, stabilizers, flame-retardant substances, plasticizers, dyes and fillers, as well as fungistatic and bacteriostatic substances, and details on the use and action of these additives are published in the Plastics Manual, Volume VT by Vieweg and Höchtlen, Carl-Hanser-Verlag, Munich 1966, e.g. described on pages 103 to 113.

According to the invention, the reaction components are reacted according to the one-step process, the prepolymer process or the semi-prepolymer process, which are known per se, machine equipment often being used, e.g. those described in U.S. Patent 2,764,565. Details of processing devices that are also suitable according to the invention are given in the plastics manual, volume VI, published by Vieweg and Höchtlen, Carl-Hanser-Verlag, Munich 1966, e.g. described on pages 121 to 205.

In foam production, foaming is often carried out in molds according to the invention. The reaction mixture is introduced into a mold. Metal, for example aluminum, or plastic, for example epoxy resin, can be used as the molding material. The foamable reaction mixture foams in the mold and forms the shaped body. The foaming of the mold can be carried out in such a way that the molded part has a cell structure on its surface, but it can also be carried out in such a way that the molded part has a compact skin and a cellular core. According to the invention, one can proceed in this connection in such a way that so much foamable reaction mixture is introduced into the mold that the foam formed just fills the mold. But you can also work so that you have more foamable Enters the reaction mixture into the mold than is necessary to fill the interior of the mold with foam. In the latter case, "overcharging" is used; such a procedure is known, for example, from US Pat. Nos. 3178 490 and 3 182 104.

In the case of mold foaming, known "external release agents" such as silicone oils are often used. However, so-called "internal release agents", optionally in a mixture with external release agents, can also be used, as described, for example, in German Offenlegungsschriften 2 121 670 and 2 307 589 have become known.

Cold-curing foams can also be produced according to the invention (cf. British patent specification 1 162 517, German patent application specification 2 153 086).

Of course, foams can also be produced by block foaming or by the double conveyor belt process known per se.

The process products are preferably flexible, semi-flexible or hard polyurethane foams. You will find the known use for such products, e.g. as mattresses and upholstery material in the furniture and automotive industry, also for the manufacture of fittings such as are used in the automotive industry and finally as insulation and means for heat or cold insulation, e.g. in the construction sector or in the refrigeration industry.

The following examples illustrate the process according to the invention without limiting it. Unless otherwise noted, quantities are to be understood as parts by weight or percentages by weight.

example 1

100 g of a mixture of 100 parts of a copolyether started on trimethylolpropane and having an average molecular weight of 4800 and consisting of 87% propylene oxide and 13% ethylene oxide

2 parts of triethanolamine,

2.3 parts of water and

1.2 parts of a mixture of equal parts by weight of bis- (dimethylamino-n-propyl) amine and N-methyl-N '- (3-formylaminopropyl) piperazine

are intensively stirred with 46 g of the phosgenation product of an industrial aniline-formaldehyde condensate (viscosity: 200 cP at 25 ° C). The foam thus obtained is partially covered with a green-colored PVC film and stored at 100 ° C. in a drying cabinet. The lightfastness of the free-foamed product is determined separately based on DIN 54 004

Comparative Example 1a:

Example 1 is repeated, but using 1.2 parts of tetramethylethylenediamine instead of the catalyst mixture according to the invention.

Comparative Example 1b:

Example 1 is repeated, but using 1.2 parts of N-dimethylamino-N '- (2-dimethylamino-propionyl) aminal instead of the catalyst mixture according to the invention.

The results of the tests are summarized in the following table:

Example 2

The procedure is as described in Example 1, but 1.2 parts of bis (3-dimethylamino-n-propyl) amine are used. The following results are obtained:

Example 3

The procedure is as described in Example 1, but 1.2 parts of N, N-bis (3-dimethylamino-n-propyl) propylene diamine are used.

Example 4

The procedure is as described in Example 1, but with 1.2 parts of a mixture of equal parts by weight of bis (3-dimethylamino-n-propyl) amine and 1-N-formyl-4-N- (2-formyl-amino-ethyl) -piperazine worked.

The following results are obtained:

Example 5

The procedure is as described in Example 1, but 1.2 parts of a mixture of equal parts by weight of bis- (3-dimethylamino-n-propyl) amine and methyl-bis- (3-N-formylamino-propyl) amine are used .

The following result of the thermal and photochemical aging tests is obtained:

Example 6

The procedure is as described in Example 1, but 1.2 parts of a mixture of equal parts by weight of bis- (3-dimethylamino-n-propyl) amine and dimethylamino-n-propyl-formamide are used. The following results are obtained:

Claims (7)

1) Process for the production of optionally cellular polyurethane plastics by reacting (a) Polyisocyanates with (b) Compounds with at least 2 isocyanate-reactive hydrogen atoms, in the presence of (c) tertiary amines as catalysts, optionally with the use of (d) blowing agents, stabilizers and other additives known per se,
characterized in that as component (c) (A) compounds of the general formula

and or

and or

and or

optionally in a mixture with (B) other tertiary amines as cocatalyst, are used, wherein the radicals R independently of one another are optionally branched alkyl groups having 1-4 C atoms the numbers n independently of one another for 2 or 3, the numbers m independently for 2 or 3 and k represents an integer between 1 and 5. 2) Process according to claim 1, characterized in that in addition to the compounds (A) of the general formulas (1) to (4) 3 to 97 mol .-%, based on the entire catalyst mixture, of further tertiary amines (B) as co- Catalyst can be used. 3) Process according to claim 1, characterized in that 10 to 90 mol .-%, based on the total catalyst mixture, of co-catalysts (B) are also used. 4) Process according to claim 1, characterized in that 30 to 70 mol .-%, based on the total catalyst mixture, of co-catalysts (B) are also used. 5) Process according to claim 1 to 4, characterized in that compounds with at least one tertiary nitrogen atom and at least one amide group are used as co-catalyst (B). 6) Verf.ihren according to claim 5, characterized in that as co-catalyst (B) formylation products of the compounds (A) of the general formulas (1) to (4) from claim 1 and / or the compounds

and or

be used
wherein R and n have the meaning given in claim 1. 7.) Method according to claim 1 to 6, characterized in that R for a methyl group, m for 2 and n stand for 3.