| 摘要 |
Polyvinyl compounds soluble or dispersible in water are manufactured by partially hydrolysing a polyvinyl ester, in the presence of a solvent therefor, with the aid of aqueous acid hydrolysing agents. The process is advantageously carried out by subjecting the polyvinyl ester, dissolved in acetic or other lower fatty acid, to the action of water in the presence of a strong mineral or other acid. Compounds in which hydrogen atoms in the vinyl residue are replaced by other atoms or groups are manufactured analogously. The products are valuable materials for sizing or impregnating fibrous materials, particularly textile yarns or other textile materials, being readily removable by washing or scouring in aqueous liquids. In an example, polyvinyl acetate is hydrolysed in 90 per cent acetic acid in the presence of sulphuric acid. The product, after separating from acetic acid, e.g. by dilution and dialysis, may be used for sizing textile yarns. Poly-(methylvinyl) acetate (obtainable by polymerizing methylvinyl acetate which may be prepared by condensing methylacetylene with acetic acid in the presence of a mercury compound) may be similarly treated. Reference has been directed by the Comptroller to Specification 351,082.ALSO:Partially hydrolysed polyvinyl esters (in which hydrogen atoms in the vinyl residue may be replaced by other atoms or groups) are valuable materials for sizing fibrous materials, especially textile yarns or other textile materials. The compounds are soluble or dispersible in water and are thus readily removable from the material by washing or scouring in aqueous solutions. An example describes the use of the compound obtained by hydrolysing polyvinyl acetate or poly-(methylvinyl) acetate in 90 per cent acetic acid in the presence of sulphuric acid, the acetic acid being removed, e.g. by dilution and dialysis. Reference has been directed by the Comptroller to Specification 351,082, [Group IV]. |
