| 摘要 |
A process for preparing a cross-linked cellular vinyl chloride polymer material comprises heating a blend of a vinyl chloride polymer with a blowing agent and an azidoformate having a boiling point of at least 100 DEG C. at a pressure of 70 mm. of mercury and having the general formula <FORM:1021706/C3/1> where x is at least 1 and R is an organic radical inert to cross-linking reactions and containing at least one carbon atom per azidoformate group, at a temperature sufficient to release gas from the blowing agent whereby blowing and cross-linking of the polymer are effected. In the examples the preferred azidoformates are tetramethylene bis(azidoformate) and 1,4-cyclohexane dimethyl bis(azidoformate) and the preferred vinylchloride polymers are poly(vinyl chloride) a vinyl chloride-vinyl acetate copolymer and a blend of poly(vinyl chloride) with chlorinated polyethylene. The blowing agent may be a chemical blowing agent, e.g. p,p1-oxy bis(benzene sulfonyl hydrazide/N,N1-dinitrosopentanethylene tetramine and azo bis (formamide) or a solvent blowing agent such as toluene. |
