DE2149613A1 - METHOD FOR MANUFACTURING FOAM SHAPED BODIES - Google Patents

Description

2149613 FARBENFABRIKEN BAYER AG

LEVERKUSEN-Bayerwerk

Central area GM / Bn patents, trademarks and licenses

k, OKi. Ϊ9 / Ι

Process for the production of foam moldings

It is known that molded bodies can be produced by foam molding polyurethanes which have a dense, closed outer skin and a microporous cellular core. Here, polyisocyanates, compounds that carry isocyanate-reactive hydrogen atoms, additives and low-boiling solvents are introduced into a closed, temperature-controlled mold. The mold is filled with the plastic while the reactive mass is foamed. The molded part has a dense outer skin and a differential density distribution across the cross-section, the minimum of which is approximately in the middle of the molded part. The molded parts produced in this way have good mechanical properties, such as Ε module, deflection and outer fiber expansion. By suitable choice of the polyol components and the isocyanate components, the mechanical properties can be largely varied and adapted to the later intended use. For example, by using long-chain linear polyethers (molecular weight 1000 to 5000) as polyol components, elastic molded parts are obtained, while the use of short-chain tri- and multifunctional polyethers (molecular weight less than 1000) results in hard products with a high E-Mudul but less Elasticity leads. So far, however, it has not been possible to improve the impact strength of the products beyond a f>-wii;; e Greta: -: beyond. For areas of application with very

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such molded body based on polyurethane.

It has long been known to crosslink polyepoxides with polyols or amines to form resins, which are usually hard and are brittle and are also unsuitable for applications that are exposed to impact stress.

It has now surprisingly been found that impact-resistant, hard moldings are obtained if polyepoxides are used at the same time Reacts with polyols and isocyanates under the conditions of foam molding. It is advantageous to adjust the amount of isocyanate to be chosen so that part of the epoxide reacts with the excess isocyanate to form oxazolidone derivatives can and at the same time part of the isocyanate under epoxy catalysis reacts further to form isocyanurate structures. The moldings obtained in this way have a dense, closed shape Outer skin and a cellular core. At the same time, in terms of their impact strength, they outperform moldings without Concomitant use of polyepoxides were produced by far.

The invention thus provides a process for the production of foam moldings with a compact surface and cellular core and with integral density distribution over the cross section of the moldings by foaming a foamable reaction mixture of polyisocyanates, hydroxyl group-containing polyethers with a molecular weight of 50 to 4000, optionally mixed with others compounds having at least two active hydrogen atoms, blowing agents and optionally auxiliaries in a closed mold, wherein the temperature of the mold inner surfaces of at least about 20 ⁰ C, preferably at least about 50 ° C under the maximum reaction temperature of the foaming reaction mixture is maintained, characterized in that 30- 100 wt.-fo, based on the rily ether and the possibly mLtzuver-

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Compounds with active hydrogen atoms polyepoxides are also used in the foaming mixture.

The production of foams is in the presence of a blowing agent, a catalyst and optionally of surface-active substances, fillers, dyes, buildable release agents, anti-aging agents, flame retardants or similar additives carried out, as they are customary in this field.

For example, detailed information on the manufacture of these types of polymer foam compositions is available from the Saunders factory & Frisch, Polyurethanes, Chemistry and Technology, Part II (1964), Interscience New York, in the work of T.H. Ferrigno, Rigid Plastic Foams (1963), pages 51 to 61, Reinhold Publishing Corporation New York and in the American patents 3,198,851, 3,242,108, 3,282 and 3,300,420 and British patent 1,070 contain.

Of course, these prior publications are only intended to provide exemplary embodiments for the production of the various Represent types of porous polymers and in no way limit the scope of the invention. Your citation is done rather, only with the aim of having to repeat very detailed repetitions of things of knowledge that are called are already known and available to the relevant specialist community.

These types of foams can therefore be produced by the one-step, the quasi-prepolymer or the actual prepolymer process, and preferably by the former, in which all reactants are measured in correct proportions and mixed together practically at the same time. In a preferred embodiment of this one-step process, the various foaming substances are delivered in premix packs in which Lo A Yj % » · ^ -

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those components which are compatible with one another and are thus storage-stable when combined are mixed together. Usually there are two packages of this type, one of which is the polyisocyanate and possibly a propellant and the like and the other the active hydrogen-containing material to be reacted with the polyisocyanate, together with possibly the catalyst, propellants and other additives.

In all ways of carrying out the invention, one brings preferably so much foaming mixture into a mold that it is "overfilled" or "packed". So you fill more mixture than would be necessary to fill the mold with unhindered expansion of the foam mass.

The ratio of the expansion space available for the foam mass in the closed form to the volume that would be occupied by the foam during expansion in the open form is generally at least about 9:10, preferably from about 8:10 to 1:10, (corresponding to a compression factor of at least about 1.1, preferably 1.25 Ms 10). The average densities of the shaped bodies are generally between 0.05 and 1.1 g / cm ³ , preferably between 0.1 and 0.7 g / cm 3.

The method according to the invention is based, inter alia, on the finding that the distribution of density over the cross-section of foam

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bodies that occur during foaming of the mixtures described above are produced in closed molds with a restricted expansion space, a function of the temperature gradient is between the molded part surface and the molded part core, which occurs during the course of the reaction. This temperature gradient results from the maximum reaction temperature inside the foamed mass in the mold and from the specified Temperature of the inner surface of the mold.

Compliance with the temperature gradient between the surfaces and the core of the foamed mass has the consequence that the finished foam bodies have compact, i.e. non-cellular surfaces and that their density depends on the surfaces decreases towards the middle, the greater the temperature difference between the surfaces and the core is, whereby certain properties of the moldings, such as heat resistance, rigidity and flexural strength, in the Compared to corresponding foam bodies with uniform density are considerably improved.

It is preferable to use molds made of a material with the highest possible thermal capacity and the highest possible thermal conductivity, preferably made of metal. However, it is also possible to use tools made of other materials, e.g. plastics such as polyepoxides or polyester resins, polyurethanes, but also optionally coated wood, glass or concrete use. As a rule, it is expedient to clean the tool surface with air or a liquid, preferably water or oil to keep the temperature constant.

As a rule, is not critical to the overall temperature level at which the inventive method is carried out, one that is, the pour the foaming process by correspondingly selected composition to be foamed masses in a to 100 ⁰ C, preheated to, for example, 50 mold and the temperature of the mold during of foaming in this

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Range hold because with appropriate choice of formulation and in such a case, the temperature in the core of the foam increases at more than 20 ⁰ C above the temperature of the mold inner surfaces.

According to the invention, the known hydroxyl group-containing polyethers with a molecular weight of 50 to 4,000 are used. Such polyethers are obtained by adding alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide to compounds with active hydrogen atoms, which serve as starting media. Such starting media are, for example, water, polyols such as ethylene glycol, propylene glycol, butylene glycol, trimethylolpropane or glycerol, amines such as ammonia, ethylene diamine, hexamethylene diamine or aniline, amino alcohols such as aminoethanol or diethanoiami η, polyphenols such as hydroquinone, 4,4'-dihydroxy methane. The alkylene oxides can also be added on in a mixture, it being possible to obtain a block-like arrangement of the alkylene oxide radicals in the adduct or an alternating arrangement. The polyethers to be used according to the invention can have secondary or primary hydroxyl groups. In many cases, preference is given to polyethers which have primary hydroxyl groups at their terminals. Those polyethers which have a hydroxyl group content of 0.5 to 18 $ are preferred. It is possible and often preferred, in addition, known per se, containing at least two hydrogen atoms reactive with isocyanate groups, for example amines or polyalcohols such as glycol, diethylene glycol, 1,4-butanediol, 1,4-butenediol, 1,4-butynediol, hexanediol 1,6, octanediol-1,8, trimethylolpropane, glycerine, pentaerythritol, sorbitol, sucrose, also to be used. Amines to be used are, for example, aniline, arylenediamines, alkylenediamines or ammonia or 3.3 ^l -dichloro-4,4'-diaminodiphenymethane and similar diamines and polyamines whose basicity is weakened by substituents. Polyesters, such as those obtained, for example, by reacting the abovementioned polyalcohols with conventional polyfunctional carboxylic acids, are also available for use. Le A 13 9-68 - 6 -

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suitable as polyfunctional carboxylic acids are e.g. phthalic acid, terephthalic acid, succinic acid, adipic acid, 1,8 octane dicarboxylic acid, called maleic acid. Farther can also contain amide-containing polyesters, such as those obtained by using amino alcohols, diamines or aminocarboxylic acids can be used. Polycaprolactones can also be used.

Double and triple bonds as well as modifying residues of unsaturated or saturated fatty acids or fatty acid alcohols containing polyesters or polyester amides can also be used.

Thioethers containing hydroxyl and / or mercapto groups as well as carboxyl groups and / or cyclic anhydride groups can also be used containing compounds which also contain ether, ester, amide, urea, urethane or ether groups can also be used.

The amounts of the optionally. connection to be used »· fertilize with several reactive Η-atoms are from 0 to 60 wt .- #, based on the polyether.

Furthermore, unsaturated aldehydes such as acrolein, glycid, oC-ß-imsaturated esters, acrylonitrile, unsaturated Acids and acid anhydrides, unsaturated ketones and their derivatives, unsaturated ethers, amides, imides, hydrazides and unsaturated hydrocarbons are also used (up to 60% by weight, based on polyether). This takes place at the Reaction according to the invention is a polymerization of these compounds. · Also polyepoxides, which are produced by converting olefins into The presence of nitriles with hydroperoxides are suitable according to the invention.

The polyepoxides can be mixed with the polyisocyanates or the polyethers before foaming. The polyepoxides are generally used in amounts of 30-100% by weight, based on the polyether and any compounds with active hydrogen atoms to be used. Le A 15 968 . - - 7 -

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In the production of the foams according to the invention, activators are preferably used in a manner customary per se, e.g. dimethylbenzylamine, N-methyl-N- (N, N-dimethylaminoethyl) piperazine, Triethylenediamine, permethylated diethylenediamine, tetramethylguanidine, trioxymethylhexahydrotriazine and / or organotin compounds, for example dibutyltin dilaurate or tin (II) octoate.

Stabilizers such as polyether-polysiloxanes, sulfonated castor or oleic acid derivatives and their sodium salts can also be used be used. The silicone stabilizers known for the production of polyurethane foams are primarily used used.

The propellant used is water and / or low boiling point Solvents such as trichloromonofluoromethane, dichlorodifluoromethane, methylene chloride and difluorotetrachloroethane. In addition, compounds that release gases when heated, such as azodicarboxylic acid esters, can easily be used decomposable carbonic acid ester anhydrides, also combinations of carbonates with acids, of isocyanates with acids or of isocyanates with water. Such propellants are generally up to 30 parts by weight, preferably 4 to 12 parts by weight per 100 parts by weight of that with isocyanate reactive components used. To achieve a low volume weight, it is also possible in extreme cases in foam production up to 50% by weight Use propellants.

Any polyisocyanates can be used according to the invention. Diisocyanates are preferred. Examples include: tetramethylene diisocyanate, hexamethylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, cyclohexane-1,4-diisocyanate, dicyclohexylmethane-4,4 ^! -diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 1-alkylbenzene-2,4- and / or 2,6-diisocyanates such as toluylene-2,4- and 2,6-diisocyanate and their technical mixtures, 3- (1 -Isocyanatoethyl) -

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phenyl isocyanate, 1-benzylbenzene-2,6-diisocyanate, 2,6-diethylbenzene-1,4-diisocyanate, Diphenylmethane-4,4'-diisocyanate, 3,3'-dimethoxydiphenylmethane-4,4'-diisocyanate, naphthylene-1,5-diisocyanate. Tri- and multifunctional polyisocyanates can of course also be used, e.g. Toluene-2,4,6-triisocyanate or obtained by aniline-formaldehyde condensation and subsequent phosgenation Polymethylene polyphenyl polyisocyanate. In addition, you can Isocyanates are also used which contain carbodiimide, uretonimine, allophanate, biuret or isocyanurate groups contain. Mixtures of the aforementioned isocyanates can also be used. In addition, can one can also use reaction products of polyhydric alcohols with polyhydric isocyanates or such polyisocyanates, as described in German patents 1,022,789 and 1,027,394.

Suitable polyepoxides to be used according to the invention are those which are broadly described in the Houben-Weil handbook, Vol 458, 2,716,123, 2,745,847, 2,745,285, 2,872,427, 2,902,518, 2,884,408, 3,268,619, 3,325,452, for example: epoxy resins made from phenols and epihalohydrins, preferably reaction products from 2.2 -Bis- (phydroxyphenyl) -propane or from polymethylene diphenols or polyalcohols and epichlorohydrin; also polyepoxides from epichlorohydrins with primary monoamines or secondary diamines such as aniline or bis (4-aminophenyl) methane. In addition, reaction products of epihalohydrins with dithiophenols, sulfonic acid amides and sulfonic acid hydrazides, polycarboxylic acids, such as glycolic acid or phthalic acid, can be used. Polyepoxides obtained by epoxidation in the presence of peracids (for example peracetic acid) with olefins are also particularly suitable. The polyepoxides usually have a molecular weight of 100 to 1000 and can have active Η atoms that react with isocyanates. However, they can also be free of active Η atoms. Le A 13 968 - 9 -

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Of course, flame-retardant additives can also be used in the process according to the invention, which can either contain groups that react with isocyanates, such as reaction products of phosphoric acid, phosphorous acid or phosphonic acid with alkylene oxides or alkylene glycols, reaction products of dialkyl phosphites, Formaldehyde and dialkanolamines as well as flame retardants that do not react with isocyanates Contain groups, e.g. tris-2-chloroethyl phosphate, tricresyl phosphate, Tris-dibromopropyl phosphate. Phosphorus compounds containing isocyanate groups can also be used in the invention Process can also be used.

The foamed moldings are suitable for the production of parts for the construction industry, e.g. for formwork elements, ceiling elements, cassettes, window frames and sashes, skylight elements, sewer gullies, swimming pool elements, excavator cabins, doors, door frames, handrails, stairs and accessories, panels, covers, Facade cladding, prefabricated walls, friction boards, furthermore for the production of everyday objects, e.g. snow shovels, shoe sole reinforcement, sandals, prosthetic parts, flower pots, furthermore for the production of parts for the locomotion industry, e.g. for crash barriers, battery boxes, shipbuilding bodies, parts for wagons, cars and ships -, aircraft construction (e.g. car bodies) as well as seating groups, dashboards, boat hulls, bumpers, also for the production of furniture parts, e.g. for furniture and furniture accessories, such as decorative parts applications, furniture feet, doors, seating furniture, office furniture and office furniture parts, complete cupboards and beds , Drawers and panels, lamp frames, p shoe furniture, kitchen furniture, shelves, panels, wood imitations, serving trolleys, picture and mirror frames. Also technical parts such as containers and container lids, handwheels, people booms, cable drums, fan blades, tapping machines, audio furniture housings, clock and barometer housings, TV housings, switch boxes, Aiffangwamen ai Le A 13 968 - 10 -

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Machines, computer cases and tables, calculating machines and writing instrument cases, cases for reading devices, accessories for Refrigerated cabinets and complete refrigerated cabinets, support rollers, machine housings, floating elements, sanitary items such as toilet sets and cupboards, urinals, cisterns, sinks, bathtubs, shower trays, humidifiers, pipes, cladding, Yarn spindles, handles of all kinds and sporting goods such as skis, ski cores, sledges, bobsleighs, cones, rifle butts, toys, Boats, balls, water skis, golf carts, paddles, sports equipment and accessories can represent process products.

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Example 1:
Component_A

57 parts by weight of a polyester consisting of adipic acid

and propylene glycol, OH number 60,

37 parts by weight of dipropylene glycol and 6 parts by weight of a polyester consisting of adipic acid,

Phthalic acid, butylene glycol and trimethylolpropane with an OH number of 210,

10 parts by weight of methylene chloride,

1 part by weight of silicone stabilizer,

0.5 part by weight of activator 1,4-diaza-bicyclo- (2,2,2) -octane,

2 parts by weight of activator N-methyl-N '- (ß-dimethyl-amino-

ethyl) piperazine
Viscosity of the mixture: ^ ₂ 5 ⁼ 1300 cP

Component_B

172 parts by weight of isocyanate based on diphenylmethane-4,4'-di-

isocyanate, which is liquefied by a 15% share of uretone imine,

32 parts by weight of diepoxide, consisting of a mixture of

70 $ 4,4'-dihydroxy-diphenylpropane, which was reacted with epichlorohydrin to diandiglycidether, and 30 # of a reaction product of aniline and epichlorohydrin

Viscosity of the mixture: ^ ₂ S ⁼ ^ ^{00 0} ^

Components A and B were mixed using a two-component metering mixer and poured into a closed, temperature-controlled metal mold. The temperature of this mold is 6O ⁰ C. '

The plastic mixture begins to foam after 13 seconds and sets after a further 11 seconds.

The molded part is removed from the mold after 10 minutes. The molding has a total density of 0.60 (g / cnr) and a material thickness of 10 mm with a massive edge zone on both sides.

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Mechanical values of the plastic produced. Flexural strength based on DIN 53 423 <? _hB ^{: 387} ( ^k P ^cm ~)

2 E-module from bending test E,: 7800 (kp. Cm ")

Tensile strength at break £ 14.5%

Practical dimensional stability in the heat under bending stress based on DIN 53 424 bending stress approx. 3 kp / cm with 10 mm deflection Heat resistance_ 68 ° C

Impact strength

from falling ball test, falling weight = 1.7 kg

Ball radius 15 mm, specimen impact surface radius = 27 mm Test specimen 60 60 χ 10 mm

Fall height 80 cm

Example 2:
Component_A

85 parts by weight of a polyether, which by accumulation

of 87 # propylene oxide and 13 # ethylene oxide of propylene glycol is formed (OH number: 28)

15 parts by weight of 1,4-butanediol

10 parts by weight of monofluorotrichloromethane

1 part by weight of silicone stabilizer

2 parts by weight of activator, N-methyl-N '- (ß-dimethyl-amino-

ethyl) piperazine

Viscosity of the mixture: ^ ₂ 5 ^{= 800 cP} Komp_onente_B

140 parts by weight of an isocyanate based on diphenylmethane

4> 4'-diisocyanate, which is liquefied by a 15 # portion of uretone imine is

35 parts by weight of diepoxide, consisting of a mixture of

70 ia dihydroxydiphenylpropane, which with

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Epichlorohydrin reacts to diandiglycidether and 30 $ of a reaction product aue aniline and epichlorohydrin.

Viscosity of the mixture: ^ 25 ^{= 57} ° ^cP

Components A and B were mixed using a two-component metering mixer and poured into a closed, temperature-controlled metal mold. The temperature of this mold is 60 ⁰ C.

The plastic mixture begins to foam after 16 seconds and sets after a further 22 seconds.

The molded part is removed from the mold after 10 minutes. The molding has an overall density of 0.60 (g / cm) and a material thickness of 10 mm with a massive edge zone on both sides.

e_sJ ^

-2 Flexural strength based on DIN 53423 _bß = 193 (kp · cm ")

ο E-module from bending test ε = 4100 (kp cm)

Elongation at break from tensile test 2. ~ = 13.8%

Practical dimensional stability in the heat

Our bending stress based on I) IN 53 424 Bending stress approx. 3 kp / cm ^ at 10 mm deflection Heat resistance: 115 ° C

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example 3:
Component A

80 parts by weight of a polyether, which is formed by the addition of 87% propylene oxide and 13% ethylene oxide to propylene glycol. OH number: 28
20 "of an adduct of propylene

oxides of trimethylolpropane. OH number: 850 10 "monofluorotrichloromethane

1 »silicone stabilizer

2 "activator tetramethylguanidine

Viscosity of the mixture ^ ₂₅ ^: 950 cP

Component B

46 parts by weight of isocyanate based on diphenylmethane-4,4'-

diisocyanate, which by a 15% Portion of uretonimine is liquefied.

Viscosity ^ 25 ^{.: 25} ° ^cP

Components A and B are mixed using a two-component metering mixer and poured into a closed metal mold. The mold temperature is 6O ⁰ C.

The plastic mixture begins to foam after 15 seconds and sets after another 15 seconds. The molding is removed from the mold after 15 minutes. The molding has an overall bulk density of 0.65 (g / enr) and a material thickness of 10 mm with a solid edge zone on both sides.

Mechanical values of the plastic produced, flexural strength based on DIN 53 423

<r _bB : <100 (kp.cnf ² )

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Ε module from bending test

E _b : <50

Elongation at break from tensile test

E,: <500 (kp.cm ² )

Practical dimensional stability in the heat under bending stress based on DIN 53 bending stress approx. 3 kp / cm with 10 mm deflection Heat resistance ; 40 ⁰ C impact strength from falling ball test. Falling weight = 1.7 kg spherical radius 15 nm> sample support surface radius 27 mm test specimen 60x60x10 mm. Fall height : 120 cm

This example shows that a relatively high impact resistance approach, prepared without polyepoxide, an insufficient heat resistance has only 40 ⁰ C.

Example 4: Component A

65 parts by weight of a polyether, which by addition

from propylene oxide to glycerine. OH number:

20 "of an adduct of propylene oxide with dipropylene glycol. OH number: 15 "1,4-butanediol 10 "monofluorotrichloromethane

1 "silicone stabilizer

2. "Activator N-methyl-N '- (ß-dimethylamino-

ethyl) piperazine The viscosity of this mixture is “c · J 900 cP

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Component B

138 parts by weight of isocyanate based on diphenylmethane

4,4'-diisocyanate, which liquefies with a 15 $ portion of uretonimine is.

97 «Diepoxide, consisting of a mixture

Clay 70 % of a reaction product of 4,4'-dihydroxydiphenyl-2,2 · propane and epichlorohydrin and 30% of a reaction product of aniline and epichlorohydrin.

The viscosity of the mixture is ₂ c ^: 400 cP

Components A and B are mixed using a two-component metering device and poured into a closed metal mold. The mold temperature is 60 ⁰ C.

The plastic mixture begins to foam after 25 seconds and sets after a further 25 seconds. After 15 minutes the molding is removed from the mold. The molding has a total density of 0.65 (g / cm) and a material thickness of 10 mm with a massive edge zone on both sides.

Mechanical values of the plastic produced, flexural strength based on DIN 53 423

_bB

Ε module from bending test

230 (kp.cm " ² )

E _b : 4500 (kp.cm " ² )

Elongation at break from tensile test

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Practical dimensional stability in the heat

under bending stress based on DIN 53 424 » Bending stress: approx. 3 kp / cm with 10 mm deflection.

Thermal flexural strength : 112 ⁰ C impact strength from falling ball test. Drop weight = 1.7 kg ball radius 7 »5 mm, sample support surface radius = 27 mm, test specimen 60x60x10 mm, drop height : 130 cm

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Claims (1)

2H9613 Pa cent entitlement: Process for the production of foam moldings with a compact surface and. cellular core and with integral density distribution over the cross-section of the molded body by foaming a foamable reaction mixture of polyisocyanates, hydroxyl group-containing polyethers with a molecular weight of 50 to 4000, optionally mixed with other compounds with at least two active hydrogen atoms, blowing agents and optionally auxiliaries in a closed form, wherein the temperature of the mold inner surfaces of at least about 20 ⁰ C, preferably at least about 50 ⁰ C under the maximum reaction temperature of the foaming reaction mixture is maintained, characterized in that 30 to 100 wt .- #, based on the PoIyäther and the optionally used compounds having active Hydrogen atoms, polyepoxides are used in the foaming mixture. Le A 13 968 - 19 - 09817/0937