| 摘要 |
Vinyl esters are polymerized in conjunction with crotonic acid or such a substitution product or functional derivative thereof as contains in the molecule only one olefinic linkage. Suitable vinyl esters include vinyl formate, acetate, propionate, butyrate, stearate, chloracetate or butoxyacetate or mixtures thereof; suitable crotonic acid derivatives include crotonic acid, b -chlorocrotonic acid, a -methylcrotonic acid, b -methylcrotonic acid and the corresponding nitriles, acid chlorides, acid amides, methyl, ethyl and propyl esters. The polymerization may be effected in solution, in emulsion or in the presence of an indifferent diluent; heat, light or catalysts may accelerate the polymerization. In examples: (1) vinyl acetate and methyl crotonate are polymerized in the presence of benzoyl peroxide; (2) vinyl acetate and ethyl crotonate are polymerized in the presence of distearoyl peroxide and benzoyl peroxide, the polymerization being initiated in a portion of the mixture, the rest being slowly added; (3) vinyl formate and crotonic nitrile are polymerized in solution in methylene chloride and in the presence of benzoyl peroxide, the product be used directly as a lacquer or the resin recovered by steam distillation; (4) vinyl chloracetate and methyl crotonate are polymerized in suspension in aqueous sodium chloride containing hydrogen peroxide; (5) vinyl acetate and ethyl crotonate are polymerized in the presence of dimethyl phthalate and dibenzoyl peroxide, yielding a product that may be used as an interlayer in the manufacture of safety glass; (6) vinyl acetate and crotonic or b -chlorocrotonic acid are polymerized in the presence of acetaldehyde and benzoyl peroxide to yield products whose salts have a foaming action; (8) vinyl formate and crotonic acid, (9) vinyl stearate, crotonic acid and formic acid, (10) vinyl n-butoxyacetate and crotonic acid, (11) vinyl chloracetate and crotonic acid, (12) vinyl acetate, vinyl stearate, and formic acid, (13) vinyl butyrate and ethyl a -methylcrotonate, or (14) vinyl acetate and methyl b -methylcrotonate, are polymerized in the presence of benzoyl peroxide; (15) vinyl acetate and ethyl crotonate are polymerized in an oxygen atmosphere.
|
