Verfahren zur Herstellung von Polylactam-Schaumstoffen

摘要

1,195,707. Foamed polylactams. E. I. DU PONT DE NEMOURS & CO. 28 June, 1967 [29 June, 1966], No. 29756/67. Headings C3C and C3R. A process for preparing a foamed polylactam, comprises carrying out the anionic polymerization of a lactam at a temperature between the melting-points of the lactam and of the polylactam in the presence of an anionic catalyst and a co-catalyst and, as blowing agent (i) an organic formate of formula R A -O-C(O)-H, R B (-OC(O)-H) 2 , or Ar11-(O-C(O)-H) n , the free valences of the polyvalent aromatic radical Ar11 being joined to a plurality (n) of formate groups, wherein R A is R c or R D , R c is Ar1- or R E -Ar11-RF-, Ar1 and Ar11 being, respectively, mono- and poly-valent aromatic radicals of 1 to 3 aromatic rings, R E being H or R G -R F -, R F being divalent -C(R G ) 2 -, the R G 's being the same or different and being H, an alkyl group or an aromatic radical of up to 7 carbon atoms, R D is a tertiary alkyl group, the tertiary carbon atom being attached to the formate radical, and R B is divalent -R-Ar11-R F -, the R F 's being the same or different; (ii) an organic formamide of formula wherein the free valences of the polyvalent aromatic radical (Ar11) are joined to a plurality (n) of formamide groups, wherein the R's and Ar11 have the same meanings as indicated above for the organic formates, and R H is R D or R M -CH=CH-CH 2 - , R M is H or an alkyl group, R J is H, R c or R E -R F -CH = CH-CH 2 -, R K is R J , an alkyl group, a heterocyclic group containing 1 to 3 hetero N atoms, or an alicyclic radical containing up to 30 carbon atoms, and R L is divalent-R F -CH = CH-CH 2 -, or a divalent alkylene group having a chain of at least 4 carbon atoms between the N atoms of the formamide groups, or (iii) an organic formate/formamide of formula where X is R J or R K , a and b are integers of at least 1 whose sum equals the number of free valences of Ar11, and Ar11, R, and R K have the same meanings as indicated above. The process is particularly suitable for preparing foamed lactams of 5-12 C atoms such as caprolactam and enantholactam. The anionic catalyst may be a lactam-base salt and is usually used in an amount 0.3-1.5 mole per cent. In the examples #-caprolactam is foamed using N,N- diphenylformamide in the presence of CaCO 3 , NaH in mineral oil, potassium stearate and poly - [2,2 - propanebis - (4 - phenyl carbonate)]. Other foaming agents specified include formanilide, p-anisole formate, tert.-butyl formate, 4-formamidophenyl formate and 2-(N-formamido)-8-aminoanthracene.