Hoechst Aktiengesellschaft

Klaus-Jurgen Behme

Hans-Matthias Deger

Andreas Zimmermann

Rolf-Michael Jansen

Claudia Schutz

Bernd Hoffmann

The invention relates to a composite foam comprising from 10 to 90% by volume of SiO.sub.2 aerogel particles and from 90 to 10% by volume of a foam, preferably a polyurethane and/or polyolefin foam, a process for its preparation and its use.

Composite foams, processes for their preparation and their use

Process for the manufacture of foams with the aid of blowing agents containing fluoroalkanes and fluorinated ethers, and foams obtained by this process. The invention relates to a process for the manufacture of foams based on polyisocyanates by the reaction of polyisocyanates, compounds containing at least two hydrogen atoms reactive towards isocyanate groups, blowing agents and, if appropriate, other additives. The blowing agents used consist to the extent of at least 10 mol % of at least one fluoroalkane of formula (I), C.sub.a H.sub.b F.sub.c, where a=2-6, b=1-12, and c=2-13, and at least one fluorinated ether of formula (II), C.sub.a H.sub.b F.sub.c O-C.sub.d H.sub.e F.sub.f, where a=1-6, b=1-12, c=1-12, d=1-2, e=0-5 and f=0-5. The invention further relates to the foams obtained by this process.

Process for the manufacture of foams with the aid of blowing agents

The invention realtes to a process for producing foams based on polyisocyanates by reacting polyisocyanates, compounds having at least two hydrogen atoms reactive towards isocyanate groups, blowing agents and, if appropriate, further additives. In this process, a blowing agent is used which is composed to the extent of at least 10 mol % of one or more fluoroalkanes of the formula I

Process for producing foams with the aid of fluoroalkanes

The invention relates to a process for producing foams based on polyisocyanates by reacting polyisocyanates, compounds having at least two hydrogen atoms reactive towards isocyanate groups, blowing agents and, if appropriate, further additives. In this process, a blowing agent is used which is composed to the extent of at least 10 mol % of one or more fluorinated ethers of the formula

Process for producing foams

Mixtures which are used for the production of polyurethane foam and which contain amines having primary or secondary aliphatic hydroxyl groups, and also customary quantities of trichlorotrifluoroethane and/or trichlorofluoromethane as a blowing agent, can be stabilized against the premature reaction of the components by adding 0.05 to 5% by weight of 2,4-diphenyl-4-methylpentene in which the ratio of the 2,4-diphenyl-4-methyl-1-pentene isomer to the 2,4-diphenyl-4-methyl-2-pentene isomer is 1:1 to 9:1, the percentages relating to the chlorofluoroalkane. In particular, these mixtures can be stabilized by adding 0.1 to 5% by weight of a mixture consisting of 45 to 89% by weight of 2,4-diphenyl-4-methyl-1-pentene, 10 to 45% by weight of 2,4-diphenyl-4-methyl-2-pentene and 1 to 20% by weight of 1,1,3-trimethyl-3-phenylindane.

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Eppstein/Taunus, Germany

Klaus-Jurgen Behme