Anisotropic foam mfr from acrylonitrile-acrylate graft polymers - on diene- acrylonitrile copolymer, for insulants for low-boiling liquids

摘要

The prodn. of anisotropic foams by heating polymers contg. blowing agent (I) to a temp. at which (I) has a vapour pressure sufficient to foam the polymer compsn. at normal external pressure and keeping the compsn. under a pressure at which no cells form, and then releasing the pressure, is carried out with a copolymer obtd. by polymn. of 100 wt. pts. mixt. of (A) =50 wt. % w.r.t. (A)+(B), of an alpha, beta-unsatd. mononitrile of the formula CH2=CR.CN (in which R is H, 1-4C alkyl or halogen) and (B) 50 wt. % ester of an olefinically unsatd. carboxylic acid of the formula CH2=CR1-COOR2 (in which R1 is H, 1-4C alkyl or halogen; R2 is 1-6C alkyl) in the presence of 1-40 pts. (C) copolymer of 50-95 wt. % butadiene and/or isoprene with 50-5 wt. % olefinically unsatd. nitrile of the formula CH2=CR-CN. The polymer is treated with blowing agents(s) and nucleating agents) kept 30-90 secs. at 90-130, pref. 100-110 degrees C under a pressure at which no cells form, then the pressure is released and the foamed compsn. is kept at least 5 hrs. at 60-90 degrees and normal pressure. Used as insulant, esp. for low-boiling liquids and liquefied gases e.g. aliphatic hydrocarbons NH3, N2, H2, CH4 or air; also as lightweight, dimensionally stable composite components for insulation against heat, cold and sound in buildings, vehicles, aircraft and ships. The foam has chemical and mechanical stability towards low-boiling liquids and liquefied gases.