Rohm and Haas Company

Andrew G Batzell

Ward Thomas Brown

Nathan Tait Allen

Karl Allen Bromm

Martin Heuts

A process for forming an opacifying pigment encapsulated in polymer including (a) dispersing a pigment particle having an average particle diameter of from 150 to 500 nm and an index of refraction of at least 1.8 such as, for example, TiO2 in a medium with from 0.1% to 10% by weight, based on the weight of said pigment particle, sulfur acid-functional first polymer whereby the zeta potential of the dispersed pigment particle is less than &#x2212;28 mV between pH 5 and pH 8; and (b) performing an emulsion polymerization in the presence of the dispersed pigment particle to provide from 10% to 200%, by weight, based on the weight of the pigment particle, second polymer that at least partially encapsulates the dispersed pigment particle. Also provided are the encapsulated pigment particle so formed and compositions including the encapsulated pigment particle.

Opacifying pigment particle

An opacifying pigment that includes a pigment particle having an average particle diameter of from 0.005 to 5 microns and an index of refraction of at least 1.8 such as, for example TiO2, at least partially encapsulated in polymer is provided. Also provided are processes for forming the encapsulated pigment particle and compositions including the encapsulated pigment particle.

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Philadelphia, PA, United States of America

Andrew G Batzell