| 摘要 |
Polymers and interpolymers of vinyl esters of monocarboxylic acids are heated with a strong base in a medium containing at least 10 per cent of a saturated secondary or tertiary alcohol of from 3 to 6 carbon atoms until between 10 and 80 per cent of the ester groups have been hydrolysed. Vinyl esters specified are vinyl formate, acetate, chloroacetate, propionate, butyrate, isobutyrate, stearate, palmitate, myristate, benzoate, toluate, cyclohexanoate, naphthoate and campholate. The interpolymers contain less than 20 mols of other polymerizable compound, for example, ethylene, propylene, isobutylene, acrylonitrile, methacrylonitrile, vinyl and vinylidene chlorides, per mol of vinyl ester; alcohols specified are isopropyl, sec.- and tert.-butyl, sec.-amyl, sec.-hexyl alcohols and cyclohexanol. Other solvents, e.g. benzene, toluene and chlorinated hydrocarbons may be present. The base may be ammonium, sodium, potassium, lithium, calcium or barium hydroxide; sodium, potassium or lithium carbonate; methylamine, dimethylamine, trimethylamine; guanidine; tetramethylammonium and trimethylsulphonium hydroxides. The solvents are removed from the hydrolysed products by evaporation, steam distillation, extraction with water or precipitation by addition of a non-solvent. The products may be plasticized if desired and used as safety glass interlayers, adhesives, coatings for fabric, paper, regenerated cellulose and polyvinyl alcohol films, and for making fibres and films. They may be cured by means of cross-linking agents. |
