| 摘要 |
1386610 Vinyl chloride polymer/vinyl or allyl monomer foams EXXON RESEARCH & ENG CO 25 Sept 1972 [21 Oct 1971] 48957/71 Heading C3C A rigid or semirigid self-skinned cellular plastic structure which has a modulus of elasticity of at least 700 Kg/cm.<SP>2</SP>, is heat recoverable (defined in terms of a specified test) and is thermoelastic (i.e. rigid at up to 75‹ C. and elastomeric at higher temperatures) is made by heating a plastisol or pregelified dryblend of a polymer of vinylchloride, polymerizable polyallyl or polyvinyl monomer (the polyallyl monomer being a non-volatile monomer containing ester, amide, epoxy or other groups known to have a solvating and plasticizing action on the vinyl chloride polymer), and a peroxide catalyst, the heating being carried out at 10- 30‹ C. per minute at least up to the temperature at which expansion starts and the reacting mass being free to expand without restraint in at least one direction, the product being a graft polymer. In the plastisol form the vinyl or allyl monomer serves as the plasticizer. The cellular material may also contain another polymer, e.g. a styrene-butadiene-acrylonitrile or -methylacrylate resin, an acrylonitrile-butadiene acrylate resin, an ethylene/vinyl acetate copolymer or a chlorinated polyethylene. The monomer may be divinyl benzene or an allyl acrylate, maleate, fumarate, phthalate or cyanate. In the examples the cellular materials also contained dicumyl peroxide as catalyst, calcium carbonate or glass fibres as fillers, a polyadipate as plasticizer and diboric lead phosphite as stabilizer. As a test of heat recoverability the cellular material was heated, cooled under pressure to form a denser product and then re-heated to form an expanded foam. |
