Ralston Purina Company

Paul M Graham

Thomas L Krinski

Charles E Coco

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.

Modified protein adhesive binder and method of producing

A method of producing a paper coating composition containing a soy protein adhesive binder which is thermally sensitive or coagulates with heating is described wherein a soy protein isolate is solubilized to form a proteinaceous adhesive binder, said binder is mixed with a mineral pigment to provide a slurry having a solids level of at least about 36% by weight of the slurry, followed by control of the pH of the slurry to between about 5.7 to 6.2 and the addition of a salt selected from the group consisting of Zinc Acetate and Zinc Formate in amounts effective to cause heat coagulation of said slurry upon heating thereof. The coating is particularly used in cast coating processes, involving the application of heat to achieve uniform smoothness of the applied coating on paper.

Growing community of inventors

Ballwin, MO, United States of America

Paul M Graham