Abstract: An improved process of cast coating and the coating composition used therein produces a paper coating which has exceptional brightness, gloss, smoothness, flexibility, resistance to drum adhesions and pick resistance. The paper coating is especially effective in cast coating where extremely high smoothness and gloss is essential. The paper coating composition utilizes soy protein binder which has been modified by copolymerization to add a synthetic component to modify the properties of the soy protein.

Abstract: A polymeric or plastic pigment, useful as a partial replacement for the inorganic pigment conventionally employed in paper coating compositions is disclosed. The pigment comprises a copolymer of an animal or vegetable protein and a monomer havingh a glass transition temperature (Tg) greater than about 70.degree. C. polymerized in a surfactant free system. When employed in paper coating compositions the pigment provides a coating of improved gloss and ink holdout, as compared to a coating in which the pigment composition consists only of an inorganic material. Improved water resistance, improved water holding and a potential for reduction in the coating sticking to the calender during the paper finishing process are obtained as compared to conventional polymeric pigments.

Abstract: A modified vegetable protein adhesive binder and a process for producing the same is disclosed wherein an alkaline protein dispersion is formed of a vegetable protein material and said dispersion is treated with a cationic monomer, preferably a cationic monomer selected from the group consisting of cationic epoxide monomers and cationic acrylate monomers, in an amount sufficient to modify the protein material. The modified vegetable protein adhesive binder has a greater affinity for pigments in a paper coating composition. This greater pigment affinity results in an improvement in the porosity of the final coating, thereby improving ink receptivity and printability on the coating surface.

Abstract: A conjugated diene such as butadiene-1,3 and a vinyl aryl monomer such as styrene are graft or over copolymerized on a dissolved or finely divided anionic fully caustic treated soy protein in aqueous alkaline media using minor effective amounts of an oil soluble azo catalyst, a chelating agent and a chain transfer agent to form a latex which can be used in paper coating compositions.

Abstract: A modified vegetable protein adhesive binder and a process for producing the same is disclosed wherein an alkaline protein dispersion is formed of the protein material and said dispersion is treated with a reducing agent in an amount sufficient to react with the disulfide bonds of the protein material in said dispersion. Initial treatment of the protein material with a reducing agent is followed by reaction of the treated dispersion with a carboxylic acid anhydride such as dicarboxylic acid anhydride, preferably phthalic anhydride in an amount sufficient to modify the protein material such that resultant alkali dispersions of the modified unhydrolyzed protein material have a relatively high viscosity but when used in paper coating compositions containing pigment and other materials such as latex produce relatively low and desirable coating viscosities. Improvements in pick strength, gloss, water holding and ink receptivity of coatings produced with the modified binder of the present invention is achieved.

Abstract: A silicate containing adhesive is disclosed which is suitable for the production of laminated paper products comprising an aqueous solution of an alkali metal silicate together with soy polysaccharides in an amount effective to thicken the silicate solution, thereby providing a silicate adhesive which has good adhesive properties and may be used for bonding of two surfaces without excess penetration of the adhesive into either of the surfaces to be bonded.