| 摘要 |
A closed cell expanded plasticized vinyl chloride polymer or copolymer contains from 5 to 25 per cent. of a solid wax having a melting point of at least 120 DEG F. uniformly dispersed throughout the plastic. Specified copolymers are those of vinyl chloride with from 2 to 30 per cent. of one of vinyl acetate, vinylidene chloride, styrene, a dialkyl maleate, an alkyl maleate, an alkyl chloromaleate, an alkyl chlorofumarate, an alkyl acrylate or an alpha-substituted alkyl acrylate. Specified waxes are paraffin, ceresin, ozokerite, carnauba and montan wax. Specified plasticizers are dibutyl and dioctyl phthalates, octyl, diphenyl and tricresyl phosphates, dioctyl sebacate, and diphenyl adipate. The wax may be added to a plastisol of the plastic containing a flowing agent, then heated in a closed mould to decompose the flowing agent, cooled, removed from the mould and further heated to expand. Specified flowing agents are alpha-alpha1-azobisisobutyronitrile, diazoaminobenzene, benzene sulphonyl hydrazide, dinitropentamethylene tetramine, the pentazdienes, the organic carbonyl azides and p-tertiary butyl benzazide. Magnesium oxide may be added as a stabilizer. |
