| 摘要 |
<p>1300722 Foamed polyamides IMPERIAL CHEMICAL INDUSTRIES Ltd 25 Nov 1970 [16 Jan 1970] 2245/70 Addition to 1226340 Heading C3C Polyamide foams are made by mixing a normally solid polyamide with a blowing agent comprising an oxalic acid derivative wherein one COOH group has been esterified with an alcohol or polyol, and the other COOH group has been esterified with an alcohol, polyol, or phenol or converted to a substituted amide group, and heating the mixture above the melting point of the polyamide. Specified polyamides are polyhexamethyleneadipamide, polycaprolactam, polyundecanolactam, polydodecanolactam, polyhexamethylene sebacamide, polyhexamethylene isophthalimide, polyhexamethylene terephthalimide, and polymetaxylylene adipamide and copolymers therefrom. Exemplified blowing agents are 1,6- bis - (butoxydicarbonylamino) - hexane, 1,6- bis - (ethoxydicarbonylamino) - hexane, poly- (ethylene oxalate), poly-(trimethylene oxalate), the reaction product of glycerol and diethyloxalate, poly(tetramethylene oxalate), dilauryloxalate, di-isooctyl oxalate, ethoxydicarbonylaminobenzene, and 1,4-bis/ethoxydicarbonyloxy)-benzene. A surface active agent, preferably of the non-ionic type may be present during heating of the polymer.</p> |
