| 摘要 |
Stable, aqueous dispersions of polymers of vinyl chloride or copolymers thereof with a minor proportion of, e.g., vinyl bromide or acetate, vinylidene chloride, acrylonitrile, methyl and ethyl acrylates, methyl methacrylate and diethyl fumarate are prepared by incorporating up to 5 per cent of a water-soluble salt, e.g. the sodium salt, of polybenzyl sulphonic acid either before, or, preferably, after polymerization. The dispersions may be prepared by emulsion polymerization using emulsifying agents, e.g. sodium and ammonium salts of sulphated or sulphonated methyl oleate, alkali salts of sulphonated aliphatic hydrocarbons, oleyl sodium sulphate and sodium stearate, catalysts, e.g. ammonium persulphate, and sodium hydroxide, ethyl palmitate and hydrated copper sulphate. The polybenzyl sulphonate may be added as a 20 per cent aqueous solution. Improved colour-stable crepes are obtained when the stabilized dispersion is spray dried, compounded with dibutyl phthalate and hot-rolled. Specifications 570,330, 570,331, 573,366, 574,482, 586,796, 587,455, 587,880, 589,264, 598,777, 599,429, 622,511, 671,647, 671,648, 10076/47, 3224/48 (as open to inspection under Sect. 91), and U.S.A. Specification 1,336,759 are referred to. |
