| 摘要 |
Polyvinyl chloride compositions, vinyl chloridevinylidene chloride and vinyl chloride-vinyl acetate copolymer compositions are stabilized against heat deterioration by addition of a dialkyl, diaralkyl, diaryl or dialkaryl tin salt of a thiocarboxylic acid or of a mixture of thiocarboxylic acid and an a , b -unsaturated carboxylic acid, The specified acids are thioacetic, thiobenzoic, and mono-esters of maleic acid e.g. mono-octyl maleate. Plasticizers (dioctyl phthalate) and lubricants (stearic acid, 'Ferrolube') may also be present.ALSO:The invention comprises dialkyl, diaralkyl, diaryl or dialkaryl tin salts of thiocarboxylic acids and dialkyl, diaralkyl, diaryl or dialkaryl tin mixed salts of thiocarboxylic acids and a , b -unsaturated carboxylic acids. Preferably the hydrocarbon groups attached to the tin atom have from two to eight carbon atoms. The thiocarboxylic acids are the thiono-and thiolocarboxylic acids, thioacetic and thiobenzoic acids being specified. Mono-esters of maleic acid, especially mono-octyl maleate, are the preferred a , b -unsaturated carboxylic acid. The salts of the invention may be prepared by reacting a hydrocarbon tin oxide with a thiocarboxylic acid with or without a a , b -unsaturated carboxylic acid at a temperature between 100 DEG and 120 DEG C., or by reacting a dihydrocarbon tin dichloride with the sodium potassium or ammonium salts of the thiocarboxylic acid and if desired of the a , b -unsaturated carboxylic acid. In the case of the mixed acids, the weight of unsaturated acid can vary between the limits 10-90%. The prepared salts may be used as heat stabilisers in polyvinyl chloride compositions, vinyl chloride-vinylidene chloride compositions and vinyl chloride-vinyl acetate compositions. |
