Rohm and Haas Company

Jack C Thibeault

William D Emmons

Willie Lau

Paul Ralph Van Rheenen

Peter Reeves Sperry

Martin Vogel

Edward Charles Kostansek

Karl Allen Bromm

David Michael Fasano

David A Larson

Chao-Jen Chung

An aqueous coating composition comprising a comb copolymer is disclosed. A method of forming a coating from the aqueous coating composition, and a coating formed by that method are also disclosed, as is a method of forming the comb copolymer. The comb copolymer is characterized in that aqueous dispersions of the comb copolymer have a Hard/Soft Balance Advantage value of at least 25%. The aqueous coating composition is capable of producing coatings having an excellent balance of hard and soft properties.

Aqueous dispersions of comb copolymers and coatings produced therefrom

An aqueous dispersion of a segmental copolymer, wherein the aqueous dispersion has a Hard/Soft Balance Advantage value of at least 25% is disclosed. A method for preparing the aqueous dispersion of a segmental copolymer is also disclosed, as is a film produced thereby.

Segmental copolymers and aqueous dispersions and films therefrom

Titanium dioxide particles are dispersed in an aqueous medium with a polymeric latex which adsorbs to the surface of the titanium dioxide to give a low-viscosity slurry or pigment grind of composite titanium dioxide-polymeric latex particles. A high glass transition polymeric latex can be used as the dispersant, and a low glass transition temperature binder latex can be added. The zeta potential of the polymeric latex can be at least about 30 millivolts more negative than the zeta potential of the titanium dioxide. The adsorbed polymeric latex provides more optimal spacing of the titanium dioxide particles in films formed from coating compositions formulated using the composite particles, and consequently greater film opacity and hiding at a given pigment volume concentration. Coatings formulated using the composite particles can be prepared to give the same hiding as coatings including titanium dioxide dispersed with conventional polyelectrolyte pigment dispersants, but with lower levels of costly titanium dioxide. Alternatively, a single selected polymeric latex can be used to both strongly adsorb to the pigment particles and to serve as binder, or a mixture of a selected, strongly adsorbing polymeric latex having a low effective glass transition temperature and a conventional binder latex can be employed.

Process for preparing an aqueous dispersion of composite particles

Inorganic material particles are dispersed in an aqueous medium with surface charge adjusting additives to give a moderately stable slurry or pigment grind. The dispersion can be used to prepare fully formulated compositions. Products formulated using the aqueous dispersion can be prepared to give the same performance as products including inorganic material dispersed with conventional polyelectrolyte pigment dispersants, but with higher levels of inorganic material, or superior performance properties with like levels of inorganic material.

Process for preparing an aqueous dispersion

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Doylestown, PA, United States of America

Jack C Thibeault