DE4203754A1 - Chloro:fluorocarbon free polyurethane moulded articles - with cellular core and compressed outer edge use acetone-water mixts. as propellant and are useful for the prodn. of steering wheels - Google Patents

Abstract

A process for the prodn. of chlorofluorohydrocarbon (CFC) free, urethane gp. contg. moulded articles (I) with a cellular core and a compressed outer edge by reaction of: (A) organic and/or modified polyisocyanates with (B) at least one higher mol. wt. cpd. with at least 2 reactive hydrogen atoms and opt. (C) lower mol. wt. chain extenders and/or crosslinking agents in the presence of (D) propellants, (E) catalysts, and opt. (F) processing aids and/or additives in a closed mould under compression whereby (D) is acetone. Also claimed is the prepn. of CFC free, soft elastic polyurethane foam moulded articles (II) with a compressed outer edge and a cellular core by reaction of (A), (B), (C), (D), (E) and (F) in a closed mould under compression whereby (D) is acetone (D1) or a mixt. of (D1) and water (D2). USE/ADVANTAGE - The process enables prodn. of integral polyurethane foam moulded articles with a pore-free smooth outer surface without the need for CFC propellant. RIM or low pressure techniques may be used to produce soft elastic moulded articles such as arm rests, head rests, interiors for motor vehicles, sports articles, bicycle and motor cycle saddles, inner shoes for ski-boots, shoe soles and steering wheels for motor vehicles. Half-hard moulded articles are suitable as side mouldings for motor vehicles and for the covering of metallic containers such as metal casks for alcoholic and non-alcoholic drinks.

Description

Process for the production of chlorofluorocarbons free moldings with a cellular core and a ver sealed edge zone, preferably of steering wheels for Ver sweeping gear.

description

The invention relates to a method for manufacturing of moldings preferably containing urethane groups, ins special motor vehicle steering wheels, with a compacted Marginal zone and a cellular nucleus, so-called integral foams, from starting materials known per se, however using acetone or mixtures of acetone and Water as a blowing agent.

The production of moldings with a cellular core and a densified edge zone by conversion of organic Polyisocyanates, higher molecular weight compounds with min at least two reactive hydrogen atoms and optionally Chain extenders and / or crosslinking agents in counter were blowing agents, preferably physically active Blowing agents, catalysts, auxiliaries and / or additives in a closed, possibly tempered form Tool has been known for a long time and is, for example, be wrote in DE-A-16 94 138 (GB-A-12 09 243), DE-C-19 55 891 (GB-A-13 21 679) and DE-B-17 69 886 (US-A-38 24 199).

A summary overview of such shaped bodies, so-called polyurethane integral foams, was at published for example in plastic manual, volume 7, Polyurethanes, edited by Dr. G. Oertel, Carl-Hanser- Verlag, Munich, Vienna, 2nd edition, 1983, pages 333ff. and in integral foams from Dr. H. Piechota and Dr. H. Röhr, Carl Hanser Verlag, Munich, Vienna, 1975.

Although the production of flexible, semi-hard or rigid polyurethane (PU) integral foam molded articles has acquired an extraordinary technical importance sen the methods described due to the increased Environmental awareness of the blowing agents used Defects. As blowing agents are used to a large extent worldwide  fluorochloroalkanes, preferably trichlorofluoromethane, used under the influence of exothermic polyadditi Vaporize the reaction first, then at elevated pressure Partially on the cooler inner wall of the mold siert and stored in the molded body. Disadvantageous these propellants are only pollution of the environment, since they are suspected in the stratosphere of mining the Ozone layer to be involved.

To reduce the fluorochloroalkane is used as a blowing agent Mainly water used, the un with the polyisocyanate The development of carbon dioxide reacts, which is actually ch propellant acts. A disadvantage of this method is that the carbon dioxide formed among those in the mold reaction conditions on the inside of the tool is condensed and so to form moldings with egg leads to a porous surface.

To avoid these disadvantages, according to the EP-A-03 64 854 for the production of moldings with a compacted edge zone and a cellular core, preferably of soft, flexible shoe soles, low as a blowing agent boiling aliphatic and / or cycloaliphatic coal water used with 4 to 8 carbon atoms.

Although with this process PU integral foams with a densified edge zone with a smooth, essentially non-porous surface and good mechanical properties can be produced, at least with the using trichlorofluoromethane as a blowing agent manufactured products are comparable, this Me method has so far been reluctant to use. prejudices exist especially with regard to the use of flammable Alkanes as blowing agents and the associated safety safety measures.

In addition to a variety of other low-boiling substances Acetone is also used as a suitable blowing agent for production hard polyester urethane foams at an early stage described. We would like to refer to the A-33 91 093 state of the art. According to the US-A-35 58 531 can be closed cell, hard PU foam fabrics are made using polyethylene  powder as nucleating agent and a mixture of cyclo pentane and acetone in a volume ratio of 85:15 to 60: 40. Her is not described in US-A-35 58 531 position of shaped bodies and in particular shaped bodies with a densified edge zone and a cellular core.

The object of the present invention was to: form containing soft elastic urethane groups body with a cellular core and a condensed margin zone with an essentially non-porous, smooth surface without the use of chlorofluorocarbons to manufacture by a simple, inexpensive process len. Suitable polyurethane formulations should be light easy to handle, flowable and even in the absence of flu hydrocarbon hydrocarbons, which act as diluents, be easy to process using RIM or low pressure technology.

Surprisingly, this task was solved by the use of acetone as a blowing agent in the manufacture the PU integral foam molded body.

The invention thus relates to a method for producing position of moldings with a cellular core and a densified edge zone by implementation of

• a) organic and / or modified organic polyiso cyanates with
• b) at least one higher molecular weight compound with mind at least two reactive hydrogen atoms and given if
• c) low molecular chain extension and / or crosslinking agents

in the presence of

• d) blowing agents,
• e) catalysts and optionally
• f) auxiliaries and / or additives

in a closed mold under compression, that characterized in that the blowing agent d) Ace clay or a mixture of acetone and water.  

The z. B. semi-hard or preferably soft elastic PU integral foam molded parts have a Border zone of higher density and a smooth essentially pore-free and bubble-free outer skin. The Shore A hardness of the The outer skin corresponds to the other mechanical egg properties foamed with chlorofluorocarbon ter integral foam molded articles. It is also advantageous the good solubility of acetone in water and its good Compatibility with polyhydroxyl compounds, so that the System components very well flowable and according to the RIM or Low pressure technology can be easily processed. Is acetone also completely biodegradable.

On the usable for the inventive method building components (a), (b) and (d) to (f) and optionally (c) Do the following:

The organic polyisocyanates (a) are aliphatic, cycloaliphatic, araliphatic and preferably aromatic polyvalent isocyanates in question.

Examples include: alkylene diisocyanates with 4 to 12 carbon atoms in the alkylene radical, such as. B. 1,12-dodecane diisocyanate, 2-ethyl-tetramethylene diiso cyanate-1,4, 2-methyl-pentamethylene-diisocyanate-1,5, tetrame ethylene-1,4-diisocyanate and preferably hexamethylene di isocyanate-1,6; cycloaliphatic diisocyanates, such as. B. Cyclohexane-1,3-and -1,4-diisocyanate and any mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanato methyl-cyclohexane (isophorone diisocyanate), 2,4- and 2,6-hexahydrotoluylene diisocyanate and the corresponding Mixtures of isomers, 4,4'-, 2,2'- and 2,4'-dicyclohexylmethane diisocyanate and the corresponding isomer mixtures, araliphatic diisocyanates, such as. B. 1,4-xylylene diiso cyanate and xylylene diisocyanate isomer mixtures and before preferably aromatic di- and polyisocyanates, such as. B. 2.4- and 2,6-tolylene diisocyanate and the corresponding Mixtures of isomers, 4,4'-, 2,4'- and 2,2'-diphenylmethane-di isocyanate and the corresponding isomer mixtures, mix gene from 4,4'- and 2,4'-diphenylmethane diisocyanates, poly phenyl-polymethylene-polyisocyanates, mixtures of 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanates and polyphenyl polymethylene polyisocyanates (raw MDI) and mixtures of  Crude MDI and tolylene diisocyanates. The organic di and Polyisocyanates can be used individually or in the form of mixtures be used.

So-called modified polyvalent iso are also common cyanate, d. H. Products by chemical conversion orga African di- and / or polyisocyanates are obtained, use det. Examples include ester, urea, biuret, Allophanate, uretonimine, carbodiimide, isocyanurate, uret Di- and / or poly containing dione and / or urethane groups isocyanates. In particular, the following may be considered: Organic, preferably aromatic, urethane groups cal polyisocyanates with NCO contents of 33.6 to 15% by weight, preferably from 31 to 21% by weight, based on the total important, for example with low molecular weight diols, triplets, Dialkylene glycols, trialkylene glycols or polyoxyalkylene glycols with molecular weights up to 4200 modified 4,4'-diphenylmethane diisocyanate or 2,4- or 2,6-tolylene diisocyanate, the di- or polyoxyalkylene glycols being the can be used individually or as mixtures, at Examples include: diethylene, dipropylene, polyoxy ethylene, polyoxypropylene and polyoxypropylene polyoxy ethylene glycols. NCO groups are also suitable Prepolymers with NCO contents of 25 to 3.5 wt.%, Preferred from 21 to 14% by weight, based on the total weight, made from the polyester described below and / or preferably polyether polyols and 4,4'-diphenyl methane diisocyanate, mixtures of 2,4'- and 4,4'-diphenyl methane diisocyanate, 2,4- and / or 2,6-tolylene diisocyanates or raw MDI. Liquid carbodi have also proven successful polyiso containing imide groups and / or isocyanurate rings cyanates with NCO contents of 33.6 to 15% by weight, preferably 31 to 21 wt.%, Based on the total weight, for. B. on Ba sis of 4,4'-, 2,4'- and / or 2,2'-diphenylmethane diiso cyanate and / or 2,4- and / or 2,6-tolylene diisocyanate.

The modified polyisocyanates can be used together or with unmodified organic polyisocyanates, such as. B. 2,4'-, 4,4'-diphenylmethane diisocyanate, crude MDI, 2,4- and / or 2,6-tolylene diisocyanate may be mixed.  

Organic polyisocyanates have proven particularly useful and therefore come preferably for the production of Weichela rigid or semi-rigid integral polyurethane foam Moldings for use: prepoly containing NCO groups mers with an NCO content of 25 to 9 wt.%, In particular based on polyether or polyester polyols and one or more diphenylmethane diisocyanate isomers, advantageous fortunately 4,4'-diphenylmethane diisocyanate and / or modifi Ornamental organic polyisocyanates containing urethane groups with an NCO content of 33.6 to 15% by weight, preferably of 31 to 21 wt .-%, especially based on 4,4'-diphenyl methane diisocyanate or diphenylmethane diisocyanate isomers mixtures, mixtures of 2,4- and 2,6-tolylene diiso cyanates, mixtures of tolylene diisocyanates and crude MDI or in particular mixtures of the aforementioned Prepolymers based on diphenylmethane diisocyanate isomes and raw MDI. Aromatic polyisocyanates, modified graced aromatic polyisocyanates or polyisocyanate mixtures advantageously have an average Functionality from 2 to 2.6, preferably 2 to 2.4 and especially 2 to 2.2.

Provided shaped bodies with light for special areas of application resistant surface, such as B. for automotive linings or neck supports, are required for their preparation preferably aliphatic or cycloali phatic polyisocyanates, especially modified polyiso cyanates based on 1,6-hexamethylene diisocyanate or isophorone diisocyanate or mixtures of said di isocyanates optionally with diphenylmethane diisocyanate and / or tolylene diisocyanate isomers used.

As higher molecular weight compounds b) with at least two reactive hydrogen atoms become polyoxyalkylene polyamines and / or preferably polyhydroxyl compounds more expedient wise those with a functionality of 2 to 6 and one Molecular weight from 500 to 8500 used, the Her position of flexible and semi-hard polyurethane-in tegral foam moldings the higher molecular weight Ver bonds (b) a functionality of preferably 2 to 3 and in particular 2.0 to 2.6 and a molecular weight of preferably 2800 to 6800 and in particular 3200 to 6000 have. Polyhydroxyl compounds have proven particularly useful  dungen, selected from the group of polyether polyols, Po polyester polyols, polythioether polyols, hydroxyl groups containing polyester amides, hydroxyl-containing poly acetal, hydroxyl-containing aliphatic polycarbonates and polymer modified polyether polyols or mixtures from at least two of the polyhydroxy compounds mentioned. Polyester polyols and / or are used in particular Polyether polyols.

Suitable polyester polyols can, for example, from orga African dicarboxylic acids with 2 to 12 carbon atoms preferably aliphatic dicarboxylic acids with 4 to 6 carbons atoms and polyhydric alcohols, preferably diols, with 2 to 12 carbon atoms, preferably 2 to 6 carbons atoms are manufactured. Come as dicarboxylic acids for example: succinic acid, glutaric acid, Adipic acid, suberic acid, azelaic acid, sebacic acid, decandi carboxylic acid, maleic acid, fumaric acid, phthalic acid, iso phthalic acid and terephthalic acid. The dicarboxylic acids can ver both individually and in a mixture with each other be applied. Instead of the free dicarboxylic acids also the corresponding dicarboxylic acid derivatives, such as. B. Tue. carboxylic acid monoesters and / or diesters of alcohols with 1 to 4 Carbon atoms or dicarboxylic anhydrides used will. Dicarboxylic acid mixtures are preferably used from succinic, glutaric and adipic acid in proportions nits from, for example, 20 to 35: 35 to 50: 20 to 32 Parts by weight, and in particular adipic acid. examples for dihydric and polyhydric alcohols, especially diols and Alkylene glycols are: ethanediol, diethylene glycol, 1,2- or 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentane diol, 1,6-hexanediol, 1,10-decanediol, glycerin, trimethylol propane and pentaerythritol. Preferably used Ethanediol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerol or mixtures of at least two the polyhydric alcohols mentioned, in particular mixtures from 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol and / or Glycerin. Polyester polyols can also be used from lactones, e.g. B. ε-caprolactone or hydroxycarboxylic acids, e.g. B. ω-hydroxycaproic acid.  

To produce the polyester polyols, the organi to z. B. aromatic and preferably aliphatic Polycarboxylic acids and / or derivatives and polyhydric alcohol le catalyst-free or preferably in the presence of Ver esterification catalysts, advantageously in one Inert gas atmosphere such as B. nitrogen, carbon mon oxide, helium, argon and the like a. in the melt at temperatures from 150 to 250 ° C, preferably 180 to 220 ° C if necessary under reduced pressure up to the desired acid number, which are advantageously less than 10, preferably less than 2 is polycondensed. According to a preferred Embodiment is the esterification mixture in the above named temperatures up to an acid number of 80 to 30, preferably 40 to 30, under normal pressure and then under a pressure of less than 500 mbar, preferably 50 up to 150 mbar, polycondensed. As esterification catalysts come for example iron, cadmium, cobalt, lead, Zinc, antimony, magnesium, titanium and tin catalysts in Form of metals, metal oxides or metal salts in Be dress. However, the polycondensation can also be in liquid Phase in the presence of diluents and / or entraining agents, such as As benzene, toluene, xylene or chlorobenzene, for azeotropic distillation of the condensation water leads.

The organic polyols are used to produce the polyester polyols Polycarboxylic acids and / or derivatives and polyhydric alcohol le advantageously in a molar ratio of 1: 1 to 1.8 preferably 1: 1.05 to 1.2 polycondensed.

The polyester polyols obtained preferably have one Functionality from 2 to 3, especially 2 to 2.6 and one Molecular weight from 1200 to 3600, preferably 1500 to 3000 and especially 1800 to 2500.

Particularly used as polyhydroxy compounds however, polyether polyols, which according to known methods for example by anionic polymerization with alkali hydroxides, such as sodium or potassium hydroxide, or alkali alcoholates, such as sodium methylate, sodium or potassium ethylate or potassium isopropylate, as catalysts and under Addition of at least one starter molecule, the 2 to 6, before preferably 2 or 3 reactive hydrogen atoms for polyethers  polyols for the production of semi-hard and soft elastic Contains PU integral foam moldings bound, or by cationic polymerization with Lewis acids, such as Antimony pentachloride, boron fluoride etherate and the like. a. or bleaching earth as catalysts with one or more alkylene oxides 2 to 4 carbon atoms in the alkylene radical can be prepared.

Suitable alkylene oxides are, for example, tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide, styrene oxide and preferably ethylene oxide and 1,2-propylene oxide. The alkylene oxides can be used individually, alternately in succession or as Mixtures are used. Come as starter molecules Examples include: water, organic dicarboxylic acids, such as succinic acid, adipic acid, phthalic acid and terephthalate acid, aliphatic and aromatic, optionally N-mono-, N, N- and N, N'-dialkyl-substituted diamines with 1 to 4 Carbon atoms in the alkyl radical, such as mono- and dialkyl-substituted ethylenediamine, 1,3-propylenediamine, 1,3- or 1,4-butylenediamine, 1,2-, 1,3-, 1,4-, 1,5- and 1,6-hexamethylenediamine, phenylenediamines, 2,3-, 2,4- and 2,6-toluenediamine and 4,4'-, 2,4'- and 2,2'-diamino-di phenylmethane.

Other suitable starter molecules are: alkanolamines, such as B. ethanolamine, N-methyl and N-ethylethanolamine, Di alkanolamines such as B. diethanolamine, N-methyl and N-ethyl diethanolamine and trialkanolamines, such as. B. Triethanolamine and ammonia. Polyvalent, in particular di- and / or trihydric alcohols and / or Dialkylene glycols, such as. B. ethanediol, 1,2-propanediol and -1,3, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerol, trimethylol propane and penta erythritol or mixtures of at least two polyvalent ones Alcohols and possibly additional water.

The polyether polyols, preferably polyoxypropylene and Polyoxypropylene-polyoxyethylene polyols, such as a functionality of 2 to 6 has already been carried out and molecular weights from 500 to 8500, and suitable poly oxytetramethylene glycols have a molecular weight of up to approximately 3500, preferably from 600 to 2200.  

Polymer-modified polyols are also suitable as polyether polyols Polyether polyols, preferably graft polyether polyols, especially those based on styrene and / or acrylonitrile, by in situ polymerization of acrylonitrile, styrene or preferably mixtures of styrene and acrylonitrile, e.g. B. in a weight ratio of 90:10 to 10:90, preferably 70: 30 to 30: 70, expediently in the aforementioned Polyether polyols analogous to the information in the German patent publications 11 11 394, 12 22 669 (US 33 04 273, 33 83 351, 35 23 093), 11 52 536 (GB 10 40 452) and 11 52 537 (GB 9 87 618) are produced, as well as polyether-polyol dispersions, that as a disperse phase, usually in an amount of 1 up to 50% by weight, preferably 2 to 25% by weight, contain: e.g. B. Polyureas, polyhydrazides, tert. Amino groups bound containing polyurethanes and / or melamine and the z. B. be are written in EP-B-0 11 752 (US 43 04 708), US-A- 43 74 209 and DE-A-32 31 497.

The polyether polyols can, just like the polyester polyo le can be used individually or in the form of mixtures. You can also use the polymer modified polyether polyols or polyester polyols and the hydroxyl groups containing polyester amides, polyacetals and / or polycarbona be mixed.

Polyether polyols with an Functionality from 2 to 3 and a molecular weight of 3200 to 6000, preferably with glycerin or trimethylol propane started polyoxypropylene-polyoxyethylene-polyols or mixtures of such polyether polyols and poly mer modified polyether polyols with functionality from 2 to 3 and a molecular weight from 3200 to 6000 selected from the group of graft polyether polyols and Polyether-polyol dispersions, the disperse phase poly ureas, polyhydrazides or tertiary amino groups contain the containing polyurethanes.

Contain polyether-polyol mixtures of the type mentioned, be pulled on the total weight, appropriately 60 to 95 wt .-%, preferably 70 to 90 wt .-% of a poly ether polyols with a functionality of 2 to 3 and one Molecular weight from 3200 to 6000 and 40 to 5% by weight, preferably 30 to 10% by weight of a graft  polyether-polyols with a functionality of 2 to 3 and a molecular weight of 3200 to 6000.

As polyacetals containing hydroxyl come z. B. from Glycols, such as diethylene glycol, triethylene glycol, 4,4'-dihydroxyethoxy-diphenyl-dimethylmethane, hexanediol and Formaldehyde-producible compounds in question. Also through Polymerization of cyclic acetals can be suitable Manufacture polyacetals.

Polycarbonates containing hydroxyl groups are such of the type known per se, for example by reacting diols, such as 1,3-propanediol, butane diol-1,4 and / or hexanediol-1,6, diethylene glycol, Trioxyethylene glycol or tetraoxyethylene glycol with diaryl carbonates, e.g. B. diphenyl carbonate, or phosgene can be.

The hydroxyl-containing polyester amides include, for. B. those of polyvalent, saturated and / or unsaturated Carboxylic acids or their anhydrides and polyvalent sown saturated and / or unsaturated amino alcohols or mixtures from polyhydric alcohols and amino alcohols and / or poly amines, mainly linear condensates.

The urethane groups containing, for example, semi-hard and preferably soft-elastic molded body with compact ter edge zone and cellular core can be without or using chain extension and / or Ver wetting agents (c) are produced. For modification the mechanical properties, e.g. B. the hardness, can however the addition of chain extenders, Vernet agents or optionally mixtures thereof as prove advantageous. As chain extension and / or ver wetting agents are used for. B. low molecular weight, more valuable alcohols, preferably diols and / or triols and Alkanolamines, preferably dialkanolamines and / or tri alkanolamines with molecular weights less than 480, before preferably from 60 to 300. Consider, for example aliphatic, cycloaliphatic and / or araliphatic Diols with 2 to 14, preferably 4 to 10, carbon atoms and dialkylene glycols with 4 to 12, preferably 4 to 6 carbon atoms such as B. ethylene glycol, 1,3-propanediol,  1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,10-decanediol, o-, m-, p-dihydroxycyclohexane, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol and Bis (2-hydroxyethyl) hydroquinone, triols, such as 1,2,4-, 1,3,5-trihydroxycyclohexane, trimethylolethane, glycerin and Trimethylolpropane, alkanolamines such as e.g. B. diethanolamine and Triethanolamine and low molecular weight hydroxyl groups Polyalkylene oxides, e.g. B. with molecular weights up to 480 Based on ethylene and / or 1,2-propylene oxide and the aforementioned ten called polyether polyol production starter molecules. As chain extension and / or crosslinking agent tel have proven themselves excellently and are therefore used especially ethylene glycol and 1,4-butanediol.

If the compounds of component (c) are also used the, these can be in the form of mixtures or individually are and are advantageously in quantities of 1 up to 30 parts by weight, preferably from 2 to 15 parts by weight and in particular 3 to 6 parts by weight, based on 100 Parts by weight of the higher molecular weight compounds (b) applied.

According to the invention, acetone, for example, is used as blowing agent (d) in an amount of 2 to 20 parts by weight, preferably 4.0 to 16.0 parts by weight and in particular 6.0 to 12 parts by weight, based on 100 parts by weight of the higher molecular compound with at least two reactive water atoms (b) used. The formation of the densified Edge zone with the smooth and very well trained compact th outer skin, the thickness of which can be up to 4 mm and the when using an amount of acetone in the Be mentioned as preferred Rich is preferably 1.5 to 3 mm thick, depends on the amount of acetone used, with increasing acetone amount of skin thickness is increased. Suitable as a blowing agent are also mixtures of acetone and water, whereby these are expediently based on 100 parts by weight of (b) contain or preferably consist of 2 to 20 parts by weight, preferably 4.0 to 16 parts by weight and in particular 6.0 to 12 parts by weight of acetone (d1) and bis to 4 parts by weight, preferably up to 0.2 parts by weight and in particular 0.2 to 0.6 part by weight of water (d2).

As the secondary pro in the polyester and polyether polyols sufficient amount of water contained in the product is required  often no separate water addition. The exact blowing agent quantity, usually in the above areas with the help of manual tests e.g. B. on the type of mold and its surfaces temperature, the desired density of the molded body and its outer skin thickness, the degree of compression and given if other characteristics can be easily determined.

As catalysts (e) for the production of the PU foam Shaped bodies are used in particular compounds that the reaction of the compounds containing hydroxyl groups the structural component (b) and optionally (c) with the or ganic, optionally modified polyisocyanates (a) speed up hard. Orga may be considered, for example African metal compounds, e.g. B. zinc stearate, zinc oleate and preferably organic tin compounds, such as. B. Tin (II) salts of organic carboxylic acids, e.g. B. Tin (II) acetate, Tin (II) octoate, Tin (II) ethylhexoate and tin (II) laurate and the dialkyltin (IV) salts of or ganic carboxylic acids, e.g. B. dibutyl tin diacetate, dibutyl tin dilaurate, dibutyltin maleate and dioctyltin diacetate, organic amidines, such as B. 2,3-Dimethyl-3,4,5,6-tetra hydropyrimidine, tertiary amines, such as. B. triethylamine, tri butylamine, methyldicyclohexylamine, dimethylbenzylamine, N-Me ethyl, N-ethyl, N-cyclohexylmorpholine, dimethylamino propylamine, bis (dimethylamino-N-propyl) methylamine, N, N, N ', N'-tetramethyl-ethylenediamine, N, N, N'N'-tetramethyl butanediamine, N, N, N'N'-tetramethyl-hexanediamine-1,6, pentams ethyl diethylene triamine, tetramethyl diaminoethyl ether, 2-hydroxy-2'-dimethylamino-diethyl ether, bis (dimethylamino propyl) urea, dimethylpiperazine, 1,2-dimethylimidazole, 1-aza-bicyclo- (3,3,0) -octane and preferably 1,4-diaza-bi cyclo (2,2,2) octane and alkanolanine compounds, such as. B. Triethanolamine, triisopropanolamine, N-methyl and N-ethyl diethanolamine and dimethylethanolamine. Use preferably 1,4-Diaza-bicyclo- (2,2,2) -octane are detected, especially in Form of a solution in ethylene glycol or 1,4-butanediol, dime thylaminopropylamine and combination of these tertiary amines with tin salts. 0.01 to are preferably used 3% by weight, in particular 0.8 to 1.4% by weight, of catalyst or Catalyst combination based on the weight of the compo nente (b). The organic metal compounds and strongly ba sische amines, preferably tertiary amines, can each  as sole catalysts or in combination with each other be used.

(f) The reaction mixture for producing the urethane groups containing, preferably soft-elastic molded body with a cellular core, a densified edge zone and one essentially pore-free, smooth outer skin can be if necessary also auxiliaries and / or additives (f) be incorporated. Examples include upper surface-active substances, foam stabilizers, cell regulators, Lubricants, fillers, dyes, pigments, flame retardants medium, internal release agent, hydrolysis protection, fungi static and bacteriostatic substances.

As surface-active substances such. B. Connections in Consider which to support the homogenization of the Serve as starting materials and are also suitable if necessary, regulate the cell structure. For example Emulsifiers, such as the sodium salts of castor oil sulfates or of fatty acids and salts of fatty acids with amines, e.g. B. oleic acid diethylamine, stearic acid diethanolamine, ricinol acidic diethanolamine, salts of sulfonic acids, e.g. B. Alkali or ammonium salts of dodecylbenzene or dinaphthylmethane disulfonic acid and ricinoleic acid; Foam stabilizers, such as Siloxane-oxalkylene copolymers and other organopoly siloxanes, ethoxylated alkylphenols, ethoxylated fat alcohols, paraffin oils, castor oil or ricinoleic acid esters, Turkish red oil and peanut oil and cell regulators such as paraffins, Fatty alcohols and dimethylpolysiloxanes. To improve the Emulsifying effect, the cell structure and / or stabilization of the foam are also suitable with oligomeric polyacrylates Polyoxyalkylene and fluoroalkane residues as side groups. The Surface-active substances are usually used in quantities from 0.01 to 5 parts by weight, based on 100 parts by weight of the Component (b) applied.

The addition of a ricinoleic acid poly has become a lubricant esters with a molecular weight of 1500 to 3500 especially proven from 2000 to 3000, the expedient preferably in an amount of 0.5 to 10% by weight, preferably two se 5 to 8 wt .-%, based on the weight of the component (b) or components (b) and (c) is used.  

As fillers, in particular reinforcing fillers fe, are the usual organic and known per se understand organic fillers and reinforcing agents. Examples include: inorganic fillers fabrics such as B. silicate minerals, for example Layered silicates such as antigorite, serpentine, hornblende, Am phibole, chrysotile, talc; Metal oxides, such as kaolin, Aluminum oxides, aluminum silicate, titanium oxides and iron oxides, Metal salts such as chalk, heavy spar and inorganic pigments such as cadmium sulfide, zinc sulfide and glass particles. As Organic fillers can be considered, for example: Carbon black, melamine, rosin, cyclopentadienyl resins and Graft polymers.

The inorganic and organic fillers can be used individually or used as mixtures and are the reaction mixture advantageously in quantities of 0.5 to 50% by weight, preferably 1 to 40 wt .-%, based on the weight of the Components (a) to (c) incorporated.

Suitable flame retardants are, for example, tricresyl phosphate, tris (2-chloroethyl) phosphate, tris (2-chloro propyl) phosphate, tris (1,3-dichloropropyl) phosphate, Tris (2,3-dibromopropyl) phosphate and tetrakis (2-chloro ethyl) ethylenediphosphate.

In addition to the halogen-substituted phosphates already mentioned inorganic flame retardants, such as red phosph hor, expandable graphite, aluminum oxide hydrate, antimony trioxide, Ar senoxide, ammonium polyphosphate and calcium sulfate or cyanur acid derivatives, such as. B. melamine or mixtures of minde least two flame retardants, such as. B. Expandable graphite and Ammonium polyphosphate, ammonium polyphosphates and melamine so such as expandable graphite and / or starch to the flame moor the molded article according to the invention ver be applied. In general, it has proven useful had 2 to 50 parts by weight, preferably 5 to 25 parts by weight the flame retardants or mixtures mentioned for each To use 100 parts by weight of components (a) to (c).

Details of the other usual above mentioned Auxiliaries and additives are in the specialist literature, for example the monograph by J.H. Saunders and K.C. Fresh  "High Polymers" Volume XVI, Polyurethanes, Parts 1 and 2, Ver Interscience Publishers 1962 or 1964, or art fabric manual, polyurethane, Volume VII, Carl Hanser Verlag, Munich, Vienna, 1st and 2nd edition, 1966 and 1983 men.

To produce the moldings, the organic, are also modified polyisocyanates (a), higher molecular compounds with at least two reactive Hydrogen atoms (b) and optionally low molecular weight Chain extender and / or crosslinking agent (c) in sol Chen amounts implemented that the equivalence ver Ratio of NCO groups of the polyisocyanates (a) to the sum of reactive hydrogen atoms of components (b) and given otherwise (c) 0.85 to 1.50: 1, preferably 0.95 to 1.15: 1 and in particular 0.9 to 1.1: 1.

The urethane groups according to the invention contain z. B. half hard or preferably soft-elastic moldings after the prepolymer or preferably after the one shot Ver drive with the help of low pressure technology or high pressure technology in closed, expediently temperature-controlled Molding tools, for example metallic molding tools, e.g. B. made of aluminum, cast iron or steel, or molds made of fiber-reinforced polyester or epoxy molding compounds be put. Because of the good flowability and verbes Processability of the formulations becomes the form body, however, in particular by means of reaction injection molding technology (RIM technology). These practices are described for example by Piechota and Röhr in "Integral foam", Carl-Hanser-Verlag, Munich, Vienna 1975; D.J. Prepelka and J.L. Wharton in Journal of Cellular Plastics, March / April 1975, pages 87 to 98, U. Knipp in Journal of Cellular Plastics, March / April 1973, pages 76 to 84 and in the plastics manual, volume 7, polyurethane, 2nd edition location, 1983, pages 333 ff.

It has proven to be particularly advantageous after the Two component process to work and build components (b), (d), (e) and optionally (c) and (f) in to combine component (A) and as component (B) the  organic polyisocyanates, modified polyisocyanates or mixtures thereof (a).

The starting components are at a temperature of 15 to 80 ° C, preferably from 25 to 55 ° C mixed and given if necessary, under increased pressure in the closed mold brought in stuff. The mixing can be done mechanically a stirrer or a stirring screw or under high pressure carried out in the so-called countercurrent injection process will. The mold temperature is expediently 20 to 120 ° C, preferably 30 to 80 ° C and especially 45 up to 60 ° C. The degrees of compaction are in the range of 1.1 to 8.3, preferably from 2 to 7 and in particular from 2.4 to 4.5.

The amount of the mixture introduced into the mold is advantageously dimensioned such that the moldings obtained have a total density of 0.06 to 0.9 g / cm ³ , z. B. the semi-hard moldings preferably a total density of 0.1 to 0.9 g / cm ³ , in particular special from 0.35 to 0.7 g / cm ³ and the soft elastic moldings preferably a total density of 0.2 to 0.7 g / cm ³ , preferably from 0.3 to 0.5 g / cm ³ .

The white produced by the inventive method Chelastic moldings are used, for example as armrests, headrests and safety covers in the Motor vehicle interior, as sporting goods and as a bicycle or motorcycle saddle. They are also suitable as inner shoes for ski boots or as shoe soles and especially as Steering wheels for means of transport, preferably motor vehicles. The semi-hard moldings are suitable for. B. as fittings boards and side panels in transport, as skis cores and for the sheathing of metallic containers, preferably of metal drums for drinks, for example alcoholic or non-alcoholic drinks such as B. beer or Fruit juices.

Examples example 1 A component

Mixture that consisted of
39.2 parts by weight of a polyoxypropylene (86% by weight) started with trimethylolpropane - polyoxyethylene (1.4% by weight) - polyols with the OH number 26,
13.0 parts by weight of a polyoxypropylene (81.4% by weight) started with propylene glycol - polyoxyethylene (18.6% by weight) - polyols with the OH number 29,
33.0 parts by weight of a graft polyether polyol with a hydroxyl number of 28, made from a glycerol-started polyoxypropylene polyoxyethylene polyol as the graft base and a mixture of styrene and acrylonitrile in a weight ratio of 12: 8 as a graft pad (Polyurax® U -26-03 from BP, Germany),
6.8 parts by weight of ethylene glycol,
0.6 part by weight of a 33% by weight solution of triethylene diamine in ethylene glycol,
0.25 part by weight of dimethylaminopropylamine,
0.55 parts by weight of triethanolamine,
0.1 part by weight of a silicone-based foam stabilizer (Tegostab® B 4690 from Goldschmidt AG, Essen)
6.0 parts by weight of a pigment paste (black paste N from Bayer AG) and
14.0 parts by weight of acetone.

B component

Mixture that consisted of
10 parts by weight of a quasi prepolymer containing urethane groups and having an NCO content of 23% by weight, prepared by reacting 4,4'-diphenylmethane diisocyanate with a mixture of dipropylene glycol and a polyoxypropylene glycol with a hydroxyl number of 250 ,
30 parts by weight of a polyisocyanate mixture containing carbodiimide groups and having an NCO content of 29.5% by weight, produced by partial carbodiimidization of 4,4'-diphenylmethane diisocyanate and
60 parts by weight of a quasi prepolymer containing urethane groups and having an NCO content of 28% by weight, prepared by reacting a mixture of 55 parts by weight of 4,4'-di-phenylmethane diisocyanates and 45 parts by weight of one Mixture of diphenylmethane diisocyanates and polyphenyl-polymethylene polyisocyanates with 9 parts by weight of a polyoxypropylene glycol with a hydroxyl number of 250.

100 parts by weight of the A component and 43 parts by weight of the B component were mixed intensively at 23 ° C and the reaction mixture in a plate-shaped aluminum mold with a size of 20 cm and heated to 50 ° C. 20 cm × 4 cm introduced in such an amount that, after foaming and curing in the closed mold, an integral foam sheet with a total density of 0.4 g / cm ³ resulted.

A molding plate with an edge zone of approximately 3 mm was obtained Thickness and a smooth surface.

Example 2 A component

Mixture that consisted of
35.8 parts by weight of a polyoxypropylene (86% by weight) started with trimethylolpropane - polyoxyethylene (14% by weight) - polyols with the OH number 26,
13.0 parts by weight of a polyoxypropylene (81.4% by weight) started with propylene glycol - polyoxyethylene (18.6% by weight) - polyols with the OH number 29,
33.0 parts by weight of a graft polyether polyol with a hydroxyl number of 28, made from a glycerol-started polyoxypropylene polyoxyethylene polyol as the graft base and a mixture of styrene and acrylonitrile in a weight ratio of 12: 8 as a graft pad (Polyurax® U 26-03 from BP, Germany),
4.5 parts by weight of ethylene glycol,
0.6 part by weight of a 33% by weight solution of triethylene diamine in ethylene glycol,
0.25 part by weight of dimethylaminopropylamine,
0.55 parts by weight of triethanolamine,
0.1 part by weight of a silicone-based foam stabilizer (Tegostab® B 4690 from Goldschmidt AG, Essen)
6.0 parts by weight of a pigment paste (black paste N from Bayer AG),
10 parts by weight of acetone and
0.2 parts by weight of water.

B component: Analogous to example 1

100 parts by weight of the A component and 35 parts by weight of the B component were mixed intensively at 23 ° C and the reaction mixture in a plate-shaped molding tool made of aluminum with the dimensions 20 cm × 20 and heated to 50 ° C cm × 4 cm introduced in such an amount that after foaming and curing in the closed mold an integral foam sheet with a total density of 0.4 g / cm ³ resulted.

The molded plate produced had an edge zone of 2.5 mm Thick and an essentially smooth surface.  

Example 3 A component

Mixture that consisted of
35.8 parts by weight of a polyoxypropylene (86% by weight) started with trimethylolpropane - polyoxyethylene (14% by weight) - polyols with the OH number 26,
13.0 parts by weight of a polyoxypropylene (81.4% by weight) started with propylene glycol - polyoxyethylene (18.6% by weight) - polyols with the OH number 29,
33.0 parts by weight of a graft polyether polyol with a hydroxyl number of 28, made from a glycerol-started polyoxypropylene polyoxyethylene polyol as the graft base and a mixture of styrene and acrylonitrile in a weight ratio of 12: 8 as a graft pad (Polyurax® U 26-03 from BP, Germany),
4.5 parts by weight of ethylene glycol,
0.6 part by weight of a 33% by weight solution of triethylene diamine in ethylene glycol,
0.25 part by weight of dimethylaminopropylamine,
0.55 parts by weight of triethanolamine,
0.1 part by weight of a silicone-based foam stabilizer (Tegostab® B 4690 from Goldschmidt AG, Essen)
6.0 parts by weight of a pigment paste (black paste N from Bayer AG),
8.0 parts by weight of acetone and
0.3 parts by weight of water.

B component: Analogous to example 1

100 parts by weight of the A component and 34 parts by weight of the B component were mixed intensively at 23 ° C and the reaction mixture in a plate-shaped aluminum mold with the dimensions 20 cm × at a temperature of 50 ° C 20 cm × 4 cm introduced in such an amount that, after foaming and curing in the closed mold, an integral foam sheet with a total density of 0.375 g / cm ³ resulted.

A molding plate with a well-defined edge was obtained zone and an essentially smooth surface at which the following mechanical properties were measured:

Border zone:
Density according to DIN 53 420 (g / cm ³ ): 1.02,
Thickness (mm): 2.5
Tensile strength according to DIN 53 504 (N / mm ² ): 7 5,
Elongation at break according to DIN 53 504 (%): 160,
Hardness of the molding plate (edge zone and cellular core) (Shorte A): 64.

Claims (12)

1. Process for the production of chlorofluorocarbon-free, urethane-containing molded articles with a cellular core and a compressed edge zone by reaction of

• a) organic and / or modified organic polyisocyanates with,
• b) at least one higher molecular weight compound with at least two reactive hydrogen atoms and, if appropriate,
• c) low molecular weight chain extenders and / or crosslinking agents

in the presence of,

• d) blowing agents,
• e) catalysts and, if appropriate,
• f) auxiliaries and / or additives, in a closed mold with compression, characterized in that Ace ton is used as blowing agent (d).

2. The method according to claim 1, characterized in that a blowing agent (d) is a mixture of acetone and Water used. 3. The method according to claim 1, characterized in that one uses as blowing agent (d), based on 100 parts by weight of the higher molecular weight compound with at least two reactive hydrogen atoms (b)
d1) 2 to 20 parts by weight of acetone and
d2) 0 to 4 parts by weight of water. 4. Process for the production of chlorofluorocarbons free of substances, flexible, flexible polyurethane foam moldings with a compressed edge zone and a cellular core by reaction of

• a) organic and / or modified organic polyisocyanates with,
• b) at least one higher molecular weight polyhydroxy compound and, if appropriate,
• c) low molecular chain extenders and / or crosslinking agents,

in the presence of

• d) blowing agents,
• e) catalysts and, if appropriate,
• f) auxiliaries and / or additives, in a closed mold with compression, characterized in that acetone (d1) or a mixture of acetone (d1) and water (d2) is used as blowing agent (d).

5. The method according to claim 4, characterized in that one uses as blowing agent (d), based on 100 parts by weight of the higher molecular weight polyhydroxyl compound (b)
d1) 4.0 to 16.0 parts by weight of acetone and
d2) 0 to 0.8 parts by weight of water. 6. The method according to any one of claims 1 to 5, characterized ge indicates that as a modified organic poly isocyanate (a) polyisocyanate containing urethane groups mixtures with an NCO content of 31 to 21 wt .-% based on diphenylmethane diisocyanates or Mixtures of diphenylmethane diisocyanates and polyphe nyl polymethylene polyisocyanates used. 7. The method according to any one of claims 1 to 6, characterized ge indicates that one as higher molecular weight compounds with at least two reactive hydrogen atoms (b) Po lyether polyols with a functionality of 2 to 3 and a molecular weight of 3200 to 6000 or mixtures  from such polyether polyols and polymer modified ten polyether polyols with a functionality of 2 to 3 and a molecular weight of 3200 to 6000 selected from the group of graft polyether polyols and Polyether polyol dispersions that function as a disperse phase Polyureas, polyhydrazides or tertiary amino groups contain bound containing polyurethanes used. 8. The method according to any one of claims 1 to 6, characterized in that a mixture is used as the higher molecular weight compounds having at least two reactive hydrogen atoms (b), which contains based on the total weight
70 to 90 wt .-% of a polyether polyol with a functionality of 2 to 3 and a molecular weight of 3200 to 6000 and
30 to 10 wt .-% of a graft polyether polyol with a functionality of 2 to 3 and a molecular weight of 3200 to 6000. 9. The method according to any one of claims 1 to 8, characterized ge indicates that as a chain extender Ethanediol or 1,4-butanediol used. 10. Method of manufacturing steering wheels for traffic agent according to one of claims 4 to 9.