Penford Products Co.

Penford Corporation

Gary R Luebke

Edward P Pauley

Charles C Nguyen

Verne J Martin

Yakov A Letuchy

Kenneth Curtis Benton

Duane E Tupper

The invention provides methods for the preparation of a starch copolymer product which is the reaction product of starch and one or more synthetic monomers capable of undergoing free radical polymerization wherein the reaction product is in the form of an emulsion or dispersion having weight-average particle sizes less than 180 nm as measured by Capillary Hydrodynamic Fractionation. The method includes the steps of: (a) dissolving or colloidally dispersing starch in an aqueous solvent to form a starch solution or dispersion; (b) heating the starch solution or dispersion to a specified temperature range; (c) adding to the starch solution or dispersion a first portion of the synthetic monomer and a free radical initiator for initiation of polymerization of the starch member and the synthetic monomer; and (d) after free radical polymerization of the synthetic monomers has been initiated in the presence of the starch, adding additional portions of synthetic monomers capable of undergoing free radical polymerization to the starch solution or dispersion. The invention also provides improved methods for the preparation of starch copolymer products utilizing wet adhesion monomers and improved industrial and architectural coatings containing the resulting starch copolymer products.

Starch copolymer products and process

The invention provides an improved method of coating mediumweight and heavyweight papers in a size press by applying a paper coating composition comprising a binder wherein the binder comprises a stable aqueous dispersion comprising a water insoluble component and a water soluble component such that the water insoluble component comprises coalescable polymer particles which have a T.sub.g less than 55.degree. C. and a majority of which have a particle size less than 1 micron; and the water soluble component comprises a water soluble polymer capable of inhibiting coalescence of said polymer particles, or a water soluble polymer and a component capable of inhibiting coalescence of said polymer particles; and wherein said water insoluble component comprises greater that 3% and less than 75% by weight of the binder solids and said water soluble component comprises greater than 25% and less than about 97% of said solids.

Size press coating method

An aqueous, salt stable polymeric dispersion comprising the reaction product of a thinned, gelatinized starch and one or more vinyl monomers, said monomer(s) comprising at least 10% 1,3-butadiene by weight is disclosed.

Salt stable starch graft polymers

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Cedar Rapids, IA, United States of America

Gary R Luebke