C CHEMISTRY; METALLURGY
C08 ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
C08J WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
C08J9/00 Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
C08J9/04 using blowing gases generated by a previously added blowing agent
C08J9/12 by a physical blowing agent
C08J9/142 Compounds containing oxygen but no halogen atom