| 摘要 |
1,133,556. Olefin-vinyl ester copolymers. RHONE-POULENC S.A. 27 June, 1967 [28 June, 1966], No. 29531/67. Heading C3P. A process for the copolymerization of vinyl esters of monocarboxylic acids with z-olefins gaseous under the polymerization temperature and pressure, comprises introducing a solution of the α-olefin in the vinyl ester progressively into an autoclave charged with water, a polymerization initiator, an emulsifier and optionally a protective colloid, said autoclave having an oxygen-free atmosphere and being connected to a source of the α-olefin to be copolymerized. The autoclave charge may comprise a dispersion of the copolymer arising from an earlier operation. The initiator, which may be introduced in stages throughout the reaction, may be an alkali metal sulphate or mixture thereof with an alkali metal bisulphite. Specified emulsifiers and protective colloids are alkali metal soaps and sulphonates, polyoxyethylene glycols and hydroxyethyl cellulose. Particle size regulators, e.g. sodium sulphate, and buffers, e.g. sodium acetate, may also be present. Specified vinyl esters are vinyl acetate, propionate, butyrate and benzoate. The products may be used in paints, varnishes and coatings. Examples describe the copolymerization of ethylene and vinyl acetate in the presence of sodium dodecylbenzene sulphonate, sodium vinyl sulphonate, hydroxyethyl cellulose, potassium persulphate and sodium acetate. |
