CA2122502A1 - Process for the manufacture of polyurethane foams - Google Patents

Abstract

PROCESS FOR THE MANUFACTURE OF POLYURETHANE FOAMS
ABSTRACT OF THE DISCLOSURE
A novel process for the manufacture of polyurethane foams by reacting a reaction mixture comprising a) a polyisocyanate component, with b) a polyol component containing no salt groups; in the presence of c) at least one blowing agent, d) catalysts. The catalyst comprise at least one carboxylic acid salt containing ether groups and no ester groups.
The reaction mixture may optionally contain e) further auxiliary substances and additives. This invention also relates to back-foaming of a plastics sheet as skin for the purpose of manufacturing composite bodies, and the composite bodies thus manufactured.

Description

21225~2 ~: Mo-4056 LeA29,sg7-us PROCESSFORTHE MANUFACTUREOFPOLYURETHANEFOAMS
BACKGROUND OFTHEINVENTION
This inven~ion relates to a novel process for the manufacture of water-blown polyurethane foams from starting materials which are known per se, in the presence of a catalyst comprising at least one carboxylic acid containing ether groups, and which is present at least partially in the form of alkali metal salt. These foams are useful in the manufacture of composite bodies by back-foaming plas~ic sheets with reaction mixtures containing these catalysts, which react fully to polyurethane foam. The invention also relates to the composite bodies thus obtained.
Water-blown foams, in particular sheet composite bodies, which ~ 10 are manufactured by back-foamin~ a plastic sheet with a reaction mixture -~; which reacts fully to form a sof~ or semi-rigid polyurethane foam, are of great importance industrially. These are widely used, for example, for interior fiffings for motor vehicles, aircraft or in the manufacture of upholstered furniture. It is essential in the majority of these fields of application that, in addition to good mechanical propcrties, influence on thermal ageing of the skin by the foams should be nil or only minimal.
~` The thermal ageing characteristics of the known back-charged foam~ (i.e. the tendency of the PVC skin toward embrittlement and crack formation) in particular constitute a problem in need of a solution.
Poor thermal stabllity results from certain constituents of the reaction mixture which reacts fully to polyurethane foam. For example, there have been attempts to replace the tertiary amines which are frequently utilized as catalysts, for example, with alkali metal salts of carboxylic acids such as, for example, potassium acetate. The use of such catalysts alone to catalyze the reaction is, however, associated with ~, ~
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- the disadvantage of an excessively long mold removal time or, in the case of elevated catalyst concentration, too short an initiation time.
Admittedly, the use of organic tin compounds generally leads to improved ageing characteristics, but the hydrolytic stability of the organic tin 5 compounds in water-containing polyol makes it difficult to ensure that activation of the polyol component remains constant over an extended storage period. In addition to improving thermal stability, compounds known as "amine trapping agents" are added to the foam system.
However, these result only to a degree of improvement, and they cannot 10 be used in amine-catalyzed systems.
U.S. Patent 4,868,043 recommends using catalysts comprising ester carboxylic acids, present in the form of alkali metal salts, of (i~ intramolecular carboxylic acid anhydrides and (ii) monohydric alcohols having no ether groups; and, in particular, of semi-esters, present in the 15 alkali metal salt form, of (i) intramolecular carboxylic acid anhydrides and long-chain diols. The compatibility of the hydroxyl and ester carboxylic ~ acid salts having no ether groups with the other partners in the reaction ;, is unsatisfactory. Finally, a feature common to both catalyst types of this patent is that their use leads to reaction mixtures which sUII fall short 20 of the optimum in terms of the practical requirement regarding the relationship between a desirably, long initiation time and a desirably, short mold removal time.
It has now been found that the problems described hereinabove can be resolved in optimal manner using the catalysts described 25 hereinbelow which are essential to the invention. The essential point of the process according to the invention, hereinafter described in greater detail, using as catalysts comprising ether carboxylates which are ` sufficiently compatible with the other constituents of the reaction mixture because of their ether group content, and which do not affect reaction Mo4056 . .
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mixture reactivity as a result of hydrolytic decomposition of the catalysts, because ester groups, which are known to be susceptible to hydrolysis, are absent. In particular, the reaction mixtures containing the catalysts according to the invention show a favorable relationship between long , -~ 5 initiation times and satisfactorily short mold rernoval times.
DESCRIPTION OF THE INVENTION
The present invention relates to a process for the manufacture of polyurethane foams by reacting a reaction mixture comprising:
a) a polyisocyanate component, 10 b) a polyol component having no salt groups, :.;
- c~ at least one blowing agent, and d) at least one catalyst.
wherein the catalyst comprises at least one carboxylic acid salt containing ether groups and no ester groups, and containing (as a .i statistical average) less than 0.3 or more than 1.3 hydroxyl groups per molecule, and is present in an amount of from 0.01 to 100 wt-%, based on the weight of component b).
The reaction mixture may additionally comprise:
e) further auxiliary substances and additives known per se in polyurethane chemistry.
The present invention also relates to the manufacture of composite bodies by back-foaming a plastics sheet as a skin with a reaction mixture ~, of the aforementioned type which reacts fully to a polyurethane foam, ' 25 and to the composite bodies thus obtained.
Suitable polyisocyanates to be utilized as component a) in the process according to the invention include any diisocyanates or polyisocyanates, and in particular those having aromatically bonded isocyanate groups. Suitable compounds include, for example, Mo4û56 I

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,,, ~22~2 2,4-diisocyanatotoluene, industrial mixtures thereof with 2,6-diisocyanato-toluene ~TDI), and, in particular, polyisocyanate mixtures of the diphenyl-methane series (MDI) which are liquid at room temperature, are preferably utilized. Of particular interest are the polyisocyanate mixtures 5 such as, for example, those obtained by reacting aniline formaldehyde condensates with phosgene, or distiliation fractions or distillation residues prepared from such products of phosgenation, or such modification products of such polyisocyanates or polyisocyanate mixtures of the diphenyimethane series such as those containing, for example, urethane, 10 carbodiimide and/or uretdione groups. The preferred, optionally chemically modified polyisocyanate mixtures of the diphenylmethane series generally exhibit an NCO content of from about 25 to 33 wt-%.
~ Component b) includes, for example, polyether polyols or mixtures `, of polyether polyols having a (average) molecular weight, calculatable 15 from the hydroxyl group content and the hydroxyl functionality, of from .
~ ! 400 to 12,000, preferably from 2,000 to 6,000, and a (average3 hydroxyl `~ functionality of from 2 to 8, preferably from 2 to 4. Suitable compounds for component b) also include mixtures of such polyether polyols with polyhydric alcohols having molecular weights below 400, which may be 20 optionally used in addition to the polyether poiyols, in a quantity of up to 25 wt-%, based on the weight of the polyether polyols.
The suitable polyether polyols include, for example, those of the type known per se, such as are obtainable by alkoxylation of suitable starter molecules in a manner which is known per se. Some examples of 25 suitable starter moiecules include ethylene glycol, propylene glycol, ` trimethylolpropane, glycerol, sorbitol, pentaerythritol or saccharose, and mixtures of such polyhydric alcohols. Utilization of polyether polyols which have been prepared by alkoxylation of trifunctional starter ~ :
molecules, in particular, trimethylolpropane and/or glycerol, is most Mo4056 .

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.:- 21~2~2 particuiarly preferred. Some of the suitable alkylene oxides for the alkoxylation reaction include, for example, propylene oxide, ethylene oxide, and mixtures of the latter two alkylene oxides. The specific alkylene oxides mentioned hereinabove may also be used sequentially in 5 the alkoxylation reaction. Additional polyols suitable for component b) -~ include those described in, for example, in ~uropean Patent 380,993, the . disclosure of which is herein incorporated by reference.
~;~ Some suitable examples of low-molecular weight polyhydric alcohols having a molecular weight below 400 include ethylene glycol, 10 propylene glycol, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, mixtures thereof, etc.
.~ Water is the preferred blowing agent for the presently claimed ; invention. However, other blowing agents may be used too. Some examples of suitable b!owing agents include, for example, halogenated 15 hydrocarbons such as trifluorochloromethane, fluoridated hydrocarbons, highly volatile organic solvents such as pentane, scetone or diethylether, , ~,...
etc. It is less preferred to use another blowing agents in addition to '`iJ water.
.
Suitable catalysts for the invention include any organic carboxylic ~ -20 acids having no ester groups and containing ether groups, which are present at least partially in the form of salt, preferably in the form of alkalimetal salt, and which contain (as a statistical average) less than 0.3 or ~ ., more than 1.3 hydroxyl groups per molecule. Preferred salts include compounds such as, for example, ether carboxylic acids present to the .
25 extent of ~rom 20 to 100% in the form of an alkali metal salt, preferably the sodium or potassium salt, which conform in terms of hydroxyl group content to the conditions mentioned; and have a molecular weight of from ~;~ 250 to 8,000, preferably from 300 to 1,000; and which (as a statistical average) contain at least 2 ether bridges per molecule; from 0 to 5, Mo4056 `!

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~ 2~62~2 - preferably from 2 to 3, hydroxyl groups per molecule; and from 1 to 6, :~ preferably from 1 to 3, carboxyl groups, per molecule, present at ieast partially in the form of a salt. The molecular weights set forth hereinabove are calculated on the free, unneutralized acid. The 5 particularly preferred catalysts are those which either exhibit no free hydroxyl groups or (as a statistical average) exhibit at least 2 hydroxyl groups, so that, in terms of the isocyanate addition reaction, they do not under any circumstances bring about chain scission but preferably extend chain length.
The suitable oatalysts d) according to the invention which are particularly preferred include, for example, acids corresponding to the general formula:
R' R"
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. (HO)m R(O--CH--CH--COOH)n 15 which meet the requirements set forth hereinabove and are present at ` least partially in the form of alkali metal salt, ` wherein in the formula: ~ :
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R represents a radical such as is obtained by removal of the . hydroxyl groups from a (m+n)hydric pGlyether alcohol which is .
:'! 20 free from ester groups and which has a molecular weight of ~om 300 to 1000, R' represents a hydrogen atom or a carboxyl group, -~'!`j R" represents a hydrogen atom or a methyl group when R' =
hydrogen, and represents a hydrogen atom when R' =
-COOH, 25 m represents an integer or (as a statistical average) a ; fractional number from 0 to 5, with exclusion of the range ~. 0.3 to 1.3, and ~ .
Mo4056 ~: 2~22~2 n stands for an integer or (as a statistical average) a ~ fractional number from 1 to 6, - wherein the sum of m+n results in a value of from 1 to 6.
The suitable catalysts for the present invention are prepared, for 5 example, by reacting (i) alcohols of the type hereinafter mentioned in greater detail, with (ii) derivatives of unsaturated carboxylic acids, in the presence of (iii) basic catalysts, with concurrent or subsequent conversion of the reaction products formed from (i) and (ii) into the ; corresponding salts for use in the invention.
Suitable alcohols (i) include compounds such as, for example, polyether alcohols having molecular weights of from 200 to 4,000, preferably 300 to 1,000, and having from 1 to 6, preferably from 2 to 3 hydroxyl groups per molecule. Mixtures of these polyether alcohols are 5~i also suitable. All data relative to molecular weight given in this context r ~
.~ 15 are calculated on the (where mixtures are used, average) rnolecular .
weight calculatable from OH content and OH functionality.
The suitable polyether alcohols include the alkoxylation products of alcohols having no ethergroups, such as, forexample, methanol, ethanol, the propanol isorners, the butanol isomers, the hexanol isomers, ~: 20 the octanol isomers, ethylene glycol, propylene glycol, glycerol, trimethylolpropane, sorbitol, pentaerythritol or mixtures of such starter , ,,~
molecules, wherein ethylene oxide and/or propylene oxide, optionally in mixture or in any sequence, islare used for the alkoxyiation.
The carboxylic acid dérivatives (ii) include any derivatives of a"B-~,~ 25 unsaturated carboxylic acids such as, for example, acrylic acid, methacrylic acid, maleic acid or fumaric acid, which can be easily converted in a simple manner into the corresponding free acids. Some examples of derivatives of the acids, which are suitable according to the invention, include the amides, nitriles and, in particular, the C1-C6-alkyl i ,~ Mo4056 , .

21225~2 .
'~ esters of the acids. Preferred carboxylic acid derivatives (ii) are C1-C6-~ alkyl esters of acrylic acid, with t-butyl acrylate being most preferred.
Some examples of suitable catalysts (iii) which accelerate the addition of hydroxyl groups of component (i) to the olefinic double bonds 5 of the components (ii) include alkali megal organyls such as phenyllithium, - butyllithium; Grignard reagents such as ethylmagnesium bromide, ammonium hydroxide; alkali metal hydroxides such as sodium hydroxide or potassium hydroxide; alkali metal alcoholates and alkali metal phenolates; alkali metal hydrides such as sodium hydride; amines such 10 as, for example, guanidine; phosphines such as, for example, ~- tributylphosphine; ion exchangers present in the OH form such as nickel acetylacetonate; and dialkyl tin oxides such as dibutyl oxide. Powdered . potassium hydroxide or potassium t-butanolate are preferred catalysts If basic alkali metal compounds of the type mentioned hereinabove by way of example are used as catalysts (iii), these not only accelerate the reaction of hydroxyl group addition to the olefinic double bonds, but also the saponification reaction with formation of the corresponding free carboxylic acids. It is frequently expedient to consider the saponification 20 reaction taking- place in situ contemporaneo.usly with the addition reaction with formation of addition compounds from the starting components (i) ~ and (ii), by either adding additional catalyst during the reaction or by : using a correspondingly greater quantity of catalyst from the outset in order to make up the quantity of catalyst consumed during the 25 saponification reaction with formation of salts. Accordingly, during the reaction of the starting components (i) and (ii), the quantity of the catalyst (iii) used may vary over a broad range of from 0.05 to 10, preferably from , 0.5 to 5, mole-%, based on the OH equivalents contained in the starting component (i).

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9 2~22~2 The starting materials (i) and (ii) in the presence of the catalysts (iii) react in a manner which is known per se in a solvent or preferably in substance within the temperature range of 0 to 100C, until the theoretical hydroxyl number of the reaction product is reached. If a 5 deficiency of the a"B-unsaturated carboxylic acid derivatives (ii) is used, calculated on the quantity of hydroxyl groups contained in the alcohol component (i), products are obtained which still exhibit free hydroxyl groups and which are hence incorporated in the process products when ~: ~ the process according to the invention is carried out. if an excess of 10 component (ii) is used in order to ensure complete reaction with the , ~, hydroxyl groups of the alcohols (i), the excess can be removed from the :
~` reaction mixture, for example by distillation, after the reaction has taken place, and may then be used again.
. The quantitative ratios of the starting components (i) and (ii) are `i 15 generally selected such that a molar ratio of alcoholic OH groups of component (i) to olefinic compounds of component (ii) of from 5:1 to 0.6:1 is present in the reaction rnixture. In accordance with the details set forth hereinabove, it is preferably ensured that the final hydroxyl functionality of the reaction products is beiow 0.3 or above 1.3.
Suitable solvents for this reaction include those solvents that are inert under the reaction conditions. Some examples of those solvents include diethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, dioxane, t-butanol, benzene, toluene, chlorobenzene, dimethylformamide, ' dimethyl sulphoxide, N-methylpyrrolidone and acetonitrile. It is preferred `' 25 that the reaction occurs in the absence of solvent.
The ether carboxylic acid derivatives which are obtained as an intermediate stage are hydrolyzed using processes which are known per ~it se. This includes, for example, by reaction with aqueous acids such as, for example, hydrohalic acids, sulfuric acid, phosphoric acid, sulfonic .
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21225~2 acids and halocarboxylic acids. Hydrochloric acid is preferred. It is in some cases advantageous to effect the hydrolysis in the presence of a solvent which can be removed again by distillation after the reaction is completed, and be used again. Suitable solvents include those solvents 5 that are inert under the reaction conditions, i.e. solvents which do not themselves undergo hydro~ysis or protonization. Some examples include diethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, dioxane, t-butanol, benzene, toluene, chlorobenzene, dimethylformamide, dimethyl sulphoxide, N-methylpyrrolidone and acetonitrile. The ether carboxylic 10 acid derivatives are generally hydrolyzed within the temperature range 50 to 11 0C.
In order to convert the alkoxy carboxylic acids which are formed into the corresponding salts, hydroxides, carbonates or bicarbonates of sodium or potassium or amine catalysts such as are conventional in 15 polyurethane chemistry are used. The bases are preferably used in the form of aqueous solutions, so that mixtures of catalyst d) according to the ~! invention and blowing agent c) occur directly, and are then mixed down with the remaining components b) and e). The salts which are used as catalysts, which are prepared by neutralization of the corresponding ether 20 carboxylic acids, may also be prepared in component b) or in a portion of the alcohols being used as component b3, so that soiutions of the catalysts d) occur directly in the polyol component b), or in a portion thereof.
If greater quantities of water are necessary to prepare the salts 25 than are required subsequently as blowing agent, the excess water may naturally be removed by distillation before carrying out the process `~ according to the invention.
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The ether carboxylic acid salts which are essential to the invention may also be prepared directly from the reaction products of the starting components (i~ and (ii), which are obtained as intermediates, by : saponiflcation with caustic liquor. Singie-stage preparation of the ` 5 catalysts d) is also possible if alkali metal hydroxides are used as catalysts for reacting the starting components (i) and (ii).
Some examples of additional ways of possibly preparing the : catalysts d) which are essential to the invention include: reacting ether . alcohols with chloroacetic acid derivatives, followed by hydrolysis and ; 10 salting out of the alkoxy acetic acid derivatives obtained; grafting of ether alcohols with acrylic acid derivatives, followed by hydrolysis and salting out of the ether carboxylic acid derivatives obtained; and partial or complete oxidation of ether alcohols using oxidants such as, for example, chromates, permanganates, nitrates, oxygen or peroxides, followed by salting out the ether carboxylic acids obtained.
The catalysts d) necessary to the invention are used in the . .
process according to the invention in a quantity of from 0.01 to 100, preferably from 0.1 to 10 wt-%, based on the weight of component b).
The reaction mixture may, in addition to the catalysts according to the invention, also contain other catalysts which are known per se.
~ However, this is less preferable. Some examples of such catalysts i~ include any alkali metal salts of c~rboxylic acids not conforming to the definition of component d), such as, for example, potassium acetate, ~ ~
potassium tartrate or potassium succinate; or classic catalysts such as ~ ~ -25 triethylenediamine, bis-(2-dimethylaminoethyl3 ether, N,N-dimethylethanol-amine, N,N,N',N",N"-pentamethyldiethylenetriamine, N-methylmorpholine, dimethylbenzylamine, tertiary alkyl phosphines, tin(ll) octoate, or dibutyl-tin-(lV) dilaurate; and metal chelates, such as, for example, acetyl acetonate chelates of magnesium, zirconium or nickel. These catalysts , ;~
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which may be optionally used in addition to those necessary to the invention, are considered to be part of group e) of the starting materials ; of the invention. If these catalysts are used, they are present in quantities of a maximum of 1.0 wt-%, based on the weight of component b).
Further auxiliary agents e) which may be optionally used include the conventional additives such as, for example, flameproofing agents, fillers, pigments, plasticizers, antistats, or cell regulating agents.
In carrying out the process according to the invention, the starting . materials described hereinabove are reacted together in quantitative ~ 10 ratios such as to correspond to an NCO index of from 60 to 140. The .~ components b) to e) are generally mixed to form a "polyol component", which is then reacted with the poiyisocyanate component using the usual methods for manufacturing polyurethane foam.
By the term NCO index, is meant the number of NCO groups divided by the number of NCO-reactive groups, multiplied by 100.
The process according to the invention is suitable for manufacturing any foam. The products of the process according to the invention are preferably, however, soft or semi-rigid polyurethane foams .~ (i.e. having a compression hardness of 20 to 400 KPa-s at 40%
deformation) having a gross density of from 30 to 500, preferably from 30 to 200 kg/m, and of the type such as those used in known manner for back-foaming plastics sheets for the purpose of manufacturing sheet composite materiais for upholstery purposes or for the interior of motor vehicles, aircraft or ships (instrument panels, inside door moldings, armrests, headrests, etc.).
Plastic sheets which are suitable for this particular purpose include those sheets which are known per se, and have been used in the manufacture of sheet composite materials by back-foaming plastic sheets with polyurethane ~oams. Some examples include sheets of polyvinyl Mo4056 ~., .. ;~ . .. . . .

2122~02 chloride (PVC), polyurethane, polymer blends of PVC and ABS, or thermoplastic polyoleflnes.
-~ The process according to the invention is preferably carried out such that the internal walls of a mold are lined at least partially with the . . .
plastic sheet to be back-foamed and the molding tool is then charged , with the foamable mixture. The sheets used for lining the molds internally may be preformed in a manner which is known per se, making - use of the known technique of deep-drawing or "powder slush".
-- The quantity of the foamable mixture introduced into the mold is ~ 10 generally calculated so as to result in foams falling within the gross ; density range set forth hereinabove.
The following examples further illustrate details for the process of this invention. The invention, which is set forth in the foregoing disclosure, is not to be limited either in spirit or scope by these exampies.
- 15 Those skilled in the art will readily understand that known variations of the conditions of the following procedures can be used. Unless otherwise noted, all percentages are by weight and all temperatures are degrees celsius. ~ -i EXAMPLES
Catalvst 1: i a) Acrylate addition ~; 1 9 powdered potassium hydroxide was dissolved or dispersed, - ~ -with slight heating, in 1500 g (1.66 OH equivalents) dehydrated polyether ;
alcohol, OH number 62, prepared from butanol and EO. At 35 to 40C, 319 g (2.49 mole) t-butyl acrylate were added dropwise to this over a period of 2 hours, with continuous stirring for 5 hours at 40C. After this, .
the catalyst was neutralized with a 37%-concentration of hydrochloric acid, and excess t-butyl acrylate was distilled in a water jet vacuum until i the sump temperature reached 80C. The resulting intermediate product `~ Mo4056 :!
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2~%25~2 had a hydroxyl number of 6.8. This corresponded to a 90% conversion , of the hydroxyl groups present initially. An ester equivalent weight of 1134.4 was calculated from this. The hydroxyl functionality of the ; reaction product was around zero.
; 5 b) Hvdrolysis 1700 9 of product (1.5 ester equivalents) from 1a), 1700 ml water and 29.6 ml (0.3 mole) 37%-concentration hydrochloric acid were stirred at 95C until distillation of t-butanol was complete. The dilute hydrochloric acid was then distilled off in a water jet vacuum until a maximum sump temperature of 80C was reached. The resulting ether acid had an acid number of 53.2. This corresponded to a carboxyl equivaient weight of 1054.5.
c) Neutralization 1400 9 (1.33 acid equivalents) of intermediate product according to 1b) were neutralized by drop-wise addition of 141.4 9 (1.26 mole) of a ~, 50%-concentration potassium hydroxide solution (degree of neutralization ' 95%, calculated on acid equivalents), with the intemal temperature held - between 25 and 35C by cooling. An 80%-concentration solution was -~, then formed by the addition of the calculated quantity of water. The ;.~ 20 resultant product had a viscosity of 130 mPa-s/25C and a base number of 42. This gave a carboxylate equivalent weight of 1335.
CatalYst 2:
. a) Acrvlate addition ~ In a manner similar to that set forth in Example 1a), 1500 9 (7.14 !'~ 25 Otl equivalents) of polyether diol, OH number 265, was prepared from propylene glycol and PO, and 1371 9 (10.71 mole) t-butyl acrylate were reacted in the presence of 4 9 powdered potassium hydroxide. The resulting intermediate product had a hydroxyl number of 23.4. This corresponded to 87% conversion of the hydroxyl groups present initially.
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~ 212~5~2 This gave an ester equivalent weight of 370.4. The hydroxyl functionality of the reaction product was around 0.25.
- b~ Hydrolysis In a manner similar to that set forth in Example 1b), 2340 g (6.32 ester equivalents) of intermediate product according to 2a), 2340 g water and 124.6 g (1.26 mole) of 37%-concentration hydrochloric acid were reacted with the addition of 500 ml of dioxane. The resulting etheric acid had an acid number of 187.4. This corresponded to a carboxyl : equivalent weight of 299.4.
c) Neutralization 1712 g (5.72 acid equivalents) of intermediate product produced according to 2b) were neutralized with 449 g (4.01 mole) of a 50%-concentration potassium hydroxide solution (degree of neutralization was 70%, calculated on acid equivalents), and a solids content of 80% was 1~ formed by the addition of water. The resulting product had a viscosity of `, 360 mPa-s/25C and a base number of 102.5. This gave a carboxylate , equivalent weight of 547.3.
~, CatalYst 3:
a) Acrylate addition ~-9 20 In a manner similar to that set forth in Example 1a~, 1500 9 (14.71 OH equivalents3 of polyether triol, OH number 550, were prepared from trimethylolpropane and PO, and 659 9 (5.15 mole) t-butyl acrylate were reacted in the presence of 8.2 g powdered potassium hydroxide. The 'I resulting intermediate product had a hydroxyl number of 272.1. This corresponded to a 31% conversion of the hydroxyl groups present initially. This gave an ester equivalent weight of 455.2. The hydroxyl functionality of the reaction product was around 2.07.

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b) HvdrolYsis In a manner similar to that of Example 1b), 2040 9 (4.48 ester equivalents) of intermediate product from 3a), 2040 9 water and 88 g (0.9 - mole) of 37%-concentration hydrochloric acid were reacted. The 5 resulting etheric acid had an acid number of 104. This corresponded to a carboxyl equivalent weight of 539.4.
c) Neutralization 1474 9 (2.73 acid equivalents) of intermediate product from 3b) were neutralized with 307 g ~2.73 mole) of a 50%-concentration 10 potassium hydroxide solution (degree of neutralization 100%, calculated on acid equivalents), and a solids content of 80% was formed by the addition of water. The resulting product has a viscosity of 500 mPa~s/25C and a base number of 75.6. This gave a carboxylate equivalent weight of 742.1.
15 CatalYst 4 . a) Acrylate addition :.i ' ~. In a manner similar to that set forth in Example 1a), 1500 9 (12 :~ OH equivalents) of polyether polyol, OH number 450 and having a functionality of 6, prepared from sorbitol and PO, and 829 9 (6.48 mole) 20 t-butyl acrylate were reacted in the presence of 6.7 9 powdered potassiurn hydroxide. The resulting intermediate product had a hydroxyl number of 157. This corresponded to 48% conversion of the hydroxyl groups present initially. This gave an ester equivalent weight of 389.1.
The hydroxyl functionality of the reaction product was around 3.12.
25 b) HYdrolysis In a manner similar to Example 1b), 2030 g (5.22 ester equivalents) of intermediate product according to 4a), 2030 g water and 103 g (1.04 mole) of a 37%-concentration hydrochloric acid were reacted.

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2~225~2 The resulting etheric acid had an acid number of 145.3. This corresponded to a carboxyl equivalent weight of 386.1.
c) Neutralization 1569 9 (4.06 acid equivalents) of intermediate product from 4b) were neutralized with 387.4 9 (3.45 mole) of a 50%-concentration potassium hydroxide solution (degree of neutralization 85%, calculated on acid equivalents~, and a solids content of 80% was formed by the addition of water. The resulting product had a viscosity of 540 mPa-s/25C and a base number of 97.7. This gave a carboxylate -equivalent weight of 574.2.
;
: Catalvst 5 :, .
a) Acrvlate addition In a manner similar to Example 1a), 224 g (1 OH equivalent) of -polyether triol, OH number ~50, prepared from trimethylolpropane, 1.1%
PO and 98.9% EO, and 192 9 (1.5 mole) t-butyl acrylate were reacted in ~, the presence of 1.2 9 of powdered potassium hydroxide. The resulting intermediate product had a hydroxyl number of 33.2. This corresponded ~, to a 81% conversion of the hydroxyl groups present initially. This gave ' an ester equivalent weight of 405.8. The hydroxyi functionality of the -~`~ 20 reaction product was around 2Ø
b) Hvdrolvsis In a manner similar to that of Example 1b), 250 9 (0.62 ester equivalents) of intermediate product according to 5a) and 113 9 (0.31 ,~ mole) of a 10%-concentration hydrochloric acid were reacted. The` 25 resulting etheric acid had an acid number of 144. This corresponded to a carboxyl equivalent weight of 389.6.
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190 g (0.49 acid equivalents) of intermediate product according to 5b) were neutralized with 38.1 g (0.34 mole) of 50%-concentration potassium hydroxide solution ~degree of neutralization 69%, calculated 5 on acid equivalents), and a solids content of 80% was formed by tha addition of water. The resulting product had a viscosity of 390 mPa-s/25C and a base number of 75.4. This gave a carboxylate equivalent weight of 744.
~,-preparation of polv-formu!ations accordina to the invention .110 100 parts by weight of a polyether polyol of OH number 28, `~ prepared by propoxylating trimethylolpropane followed by ethoxylating the propoxylation product (weight ratio of PO: EO = 85: 15) were mixed i~ with catalyst in two parallel experiments. In each case, these mixtures were then mixed with water, so that the mixture contained 3.2 parts by . 15 weight of water.
The catalyst concentrations were in all examples selected such that approximately identical rise times resulted (i.e. 150 + 10 sec.).
PolYisocvanate component A polyisocyanate mixture of the diphenylmethane series having a 20 viscosity (23C) of 200 rnPa.s and an NCO content of 32 wt-%
obtained by phosgenation of an aniline-forrnaldhyde-condensate `i consisting of a mixture of 50 wt-% of monomeric MDI-isomers and of 50 wt-% of higher horno3Ogs thereof was used in the exarnples which follow Examples accordinq to the invent on and Comparative Examples The foams were prepared using the hand foaming method. In this method, all components, with the exception of the polyisocyanate 25 component, were pre-stirred (1,000 rpm) for 30 sec. The polyisocyanate .' component was then added, and stirring continued for a further 10 sec.
at 25C. The NCO index in all examples was 100.
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Th0 initiation, rise and setting times were determined, with the poiyol formuiation being combined with the polyisocyanate component in a 660 ml cardboard beaker, while stirring at 25C. The initiation time was the time which elapsed from the ~ime of polyisocyanate addition to the commencement of foaming; the rise time was the time which elapsed from poiyisocyanate addition to the termination of foaming; the setting ; time was the time which elapsed from polyisocyanate addition until the foam ceased to be tacky.
!.' Example A was according to the invention, using 8.0 parts by weight of catalyst 1.
'; Example B was according to the invention, using 4.0 parts by weight of catalyst 2. -Example C was according to the invention, using 4.0 parts by weight of catalyst 3.
~ 15 Example D was according to ~he invention, using 4.0 parts by :~ weight of catalyst4.
Example E was acccrding to the invention, using 3.75 parts by weight of catalyst 5.
Example F was a Comparative Example, and followed the same procedure as Example A, except that the catalyst according to the invention was replaced by 0.3 parts by weight of potassium acetate.
Example G is a Comparative Example, and followed the same procedure as Example A, except that the catalyst according to the invention was replaced by 0.3 parts by weight N,N,N',N'-tetramethyi ~ 25 hexamethylenediamine.
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Initiation ::` time (s) 15 17 18 34 24 18 15 ,. , Rise time .~, 5 (s) 142 140 155 157 135 161 141 Although the invention has been described in detail in the :: foregoing for the purpose of illustration, it is to be understood that such ~; detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of -: 1û the invention except as it may be limited by the claims.

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Claims (10)

1. In a process for the manufacture of polyurethane foams by reacting a reaction mixture comprising:
a) a polyisocyanate component, b) a polyol component containing no salt groups, c) at least one blowing agent, and d) a catalyst, the improvement wherein said catalyst comprises at least one carboxylic acid salt containing ether groups and no ester groups, and containing (as a statistical average) less than 0.3 or more than 1.3 hydroxyl groups per molecule, and is present in an amount of from 0.01 to 100 wt-%, based on the weight of component b).

2. The process of Claim 1 wherein said reaction mixture additionally comprises:
e) auxiliary substances and/or additives.

3. In a process for the preparation of composite bodies comprising the steps of lining all or part of the internal walls of a mold with a plastic sheet, filling the mold with a reaction mixture, allowing the reaction mixture to fully react, and removing the composite body from the mold, wherein said reaction mixture comprises:
a) a polyisocyanate component, b) a polyol component containing no salt groups, c) at least one blowing agent, and d) a catalyst;
the improvement wherein said catalyst comprises at least one carboxylic acid salt containing ether groups and no ester groups, and containing (as a statistical average) less than 0.3 or more than 1.3 hydroxyl groups per molecule, and is present in an amount of from 0.01 to 100 wt-%, based on the weight of component b).

4. The process of Claim 3 wherein said reaction mixture additionally comprises:
e) auxiliary substances and/or additives.

5. The process of Claim 1 wherein said carboxylic acid salt is present at least partially in the form of an alkali metal salt, and corresponds to the general formula:

wherein:
R represents a radical obtained by removal of the hydroxyl groups from a(m+n)hydric polyether alcohol which is free from ester groups and which has a molecular weight of from 300 to 1000;
R' represents a hydrogen atom or a carboxyl group;
R" represents a hydrogen atom or a methyl group when R' =
hydrogen, and a hydrogen atom when R' = -COOH;
m represents an integer or as a statistical average a fractional number from 0 to 5, with exclusion of the range 0.3 to 1.3;
and n represents an integer or as a statistical average a fractional number from 1 to 6;
wherein the sum of m+n equals a number from 1 to 6.

6. The process of Claim 1 wherein said polyisocyanate component comprises a polyisocyanate or a polyisocyanate mixture of the diphenylmethane series, which are liquid at room temperature.

7. The process of Claim 6 wherein said polyisocyanate of the diphenylmethane series contains urethane, carbodiimide and/or uretdione groups.

8. The process of Claim 1 wherein said polyol component is selected from the group consisting of 1) polyether polyols or mixtures of polyether polyols having an average hydroxyl functionality of from 2 to 4 and a molecular weight of from 400 to 12,000, and 2) mixtures of polyether polyols having an average hydroxyl functionality of from 2 to 4 and a molecular weight of from 400 to 12,000, with up to 25 wt-%, based on the total weight of component b), of di- and/or tri-hydric alcohols having a molecular weight of below 400.

9. The process of Claim 1 wherein said blowing agent comprises water.

10. Composite bodies produced by the process of Claim 3.