Water-soluble film from copolymers of vinyl alcohol and itaconic acid, and paper coating articles therefrom
View Patent ↗The present invention is a composition useful for coating the surface of paper wherein the coating composition is an aqueous solution comprising less than 40 wt % water and consisting essentially of a polyvinyl alcohol copolymer that is at least about 95 % hydrolyzed, and a process for preparing the same.
1. A water-soluble film useful for coating the surface of paper wherein said film is prepared from a coating composition having an aqueous phase, said aqueous phase comprising a copolymer comprising units of vinyl alcohol, alkyl acrylate, itaconic acid and optionally vinyl acetate, said copolymer comprising i) less than about 5 mol % vinyl acetate units; (ii) about 1 mol % to about 10 mol % itaconic acid units; (iii) at least about 90 mol % vinyl alcohol units and (iv) about 1 mol % to about 9 mol % alkyl acrylate units, wherein said copolymer is completely dissolved in said aqueous phase of the coating composition and the amount of water present in said aqueous phase is such that the concentration of water in the coating composition is less than 40% by weight, based on the total weight of the coating composition.
2. An article comprising the water-soluble film of claim 1 .
3. The film of claim 1 wherein the copolymer comprises less than about 3 mol % vinyl acetate units and from about 2 mol % to about 8 mol % itaconic acid units.
4. The film of claim 3 wherein the copolymer comprises less than about 1 mol % vinyl acetate units and from about 3 mol % to about 6 mol % itaconic acid units.
5. The film of claim 1 wherein the copolymer comprises from about 2 mol % to about 8 mol % itaconic acid units and from about 1 mol % to about 9 mol % alkyl acrylate units.
6. The film of claim 5 wherein the copolymer comprises from about 3 mol % to about 6 mol % itaconic acid units and from about 1 mol % to about 9 mol % alkyl acrylate units.
7. A water-soluble film comprising a hydrolyzed, lactonized vinyl acetate terpolymer composition comprising vinyl alcohol, methyl acrylate, and itaconic acid moieties, wherein: (i) the terpolymer comprises less than about 5 mol % of vinyl acetate moieties; (ii) the methyl acrylate comonomer units in the terpolymer are present in an amount of at least about 1 mol % up to about 9 mol %; (iii) the itaconic acid comonomer units in the terpolymer are is present in an amount of at least about 1 mol % up to about 9 mol %, and, (iv) the methyl acrylate comonomer units of the terpolymer exists in the form of lactones.
8. An article comprising the water-soluble film of claim 7 .