| 摘要 |
In a method of making water-soluble polyvinyl alcohol derivatives, a mixture of polyvinyl alcohol (containing at least 50 mol. per cent of vinyl alcohol units), 2 to 50% by weight of the polyvinyl alcohol of urea, and up to 8% by weight of the polyvinyl alcohol of water or organic solvent is heated at 150 DEG to 230 DEG C. under conditions such that air is not supplied to the mixture, and preferably in an inert atmosphere. The polyvinyl alcohol is preferably in powder form, and may be mixed with an aqueous or organic solvent solution of the urea, or with powdered urea. The products may be used in sizes and finishing agents, and in the manufacture of water-soluble films. Specification 934,086 is referred to. |
