This patent of Kao Soap describes the anti caking properties of granular urea by treatment of an aqueous solution of a (1) substantially water insoluble polymer of polyvinyl acetate, polyvinyl acetals, partially saponified acetate, partially acetylated polyvinyl alcohol, esters of polyacryclic acid and an aliphatic alcohol, or copolymers thereof with another copolymerizable monomer, dissolved in (2) an aqueous solution of alkyl sulfates, alfa-olefin sulfonates containing six to ten carbon atoms or alkylbenzenesulfonates in which the alkyl radical contains four to eight atoms.

1972 Maruta 3660070 Anti Caking.pdf