Verfahren zur Herstellung von Epoxidschaumstoffen

摘要

Foaming and hardening epoxy resins under the action of a carbamate of at least one primary or secondary polyamine optionally in admixture with at least one primary or secondary polyamine as additional hardener. Foaming is achieved by thermal decomposition of the carbamate in the temperature range 20-200 DEG C. to give carbon dioxide and the free polyamine. Polyepoxy compounds based on specified mono-nuclear phenols containing two hydroxyl groups, multi-nuclear phenols or bis-phenols, aliphatic poly-epoxides of diols or polyols and their high molecular weight reaction products with ethylene oxide and/or propylene oxide may be used. In particular epichlorhydrin derivatives of mono-nuclear dihydric phenols, bis-phenols such as 2,2-di-(p-hydroxyphenyl) propane, aliphatic diols or aliphatic polyols such as glycerol are specified. The preferred carbamates are compounds of the formula wherein R is a straight or branched chain aliphatic, cycloaliphatic, aromatic or araliphatic radical and n is an integer from 0 to 30, compounds of the formula wherein R1 and R2 have the same significance as R above, R3 is branched or unbranched saturated or unsaturated aliphatic, cycloaliphatic or araliphatic and n is an integer in the range 0 to 10 as well as carbamates obtained by the action of carbon dioxide on specified aliphatic or cycloaliphatic primary, secondary or primary-secondary polyamines, aromatic diamines and di-(aminophenyl)alkanes. The free polyamines corresponding to the above-mentioned carbamates can also be present as the additional hardening agents. Specified surface active agents such as polysiloxanes or polyepoxides may be incorporated and, if desired, a filler, a dyestuff, a plasticizer, a fire-retarding agent or a mixture of any two or more of these substances may be present. The foamed products may find application in thermal, acoustic or electrical insulation. Carbamates of the first general formula above, which are soluble in amines and polyepoxide resins, are obtained by treating acrylonitrile with the appropriate specified di- or poly-ol and reacting the hydrogenated product with carbon dioxide. Carbamates of the second general formula above are obtained by treating specified 1,2-alkylene oxides with specified di- or poly-amines and reacting the product with carbon dioxide.