| 摘要 |
Process for the preparation of water-soluble copolymers, and the use thereof as sizing agents A b s t r a c t Process for the preparation of aqueous solutions of hydrolysed styrene/acrylonitrile copolymers, the carboxyl groups of which are entirely or partly present as NH4 and/or alkali metal salt, characterized in that a) 40-90% by weight of acrylonitrile, b) 10-60% by weight of styrene and c) 0-20% by weight of further monomer which can be hydrolysed by alkali are subjected to suspension or emulsion polymerization, the aqueous dispersion or emulsion is subsequently hydrolysed at 90-220.degree.C in the presence of alkali metals and/ or alkaline earth metals, and, if appropriate, the copolymer solution is treated with hydrogen peroxide wherein a part of the styrene may be replaced by a further monomer which cannot be hydrolysed by alkali. |
