Dry, water-dispersible pigment compositions
AssigneeHercules Incorporated
InventorsJohn Guzi, Jr., William J. Hart
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Abstract
Dry pigment compositions which are easily dispersed in aqueous systems are described. The compositions contain 55 to 80% of a pigment and 45 to 20% of a nonionic material comprising, by weight of the pigment, 15 to 45% of a nonionic dispersing agent and 10 to about 67% of a water-dispersible, at least partially hydrolyzed polymer of vinyl acetate or a polymer of an N-vinyl pyrrolidone.
Claims11
A process for preparing a dry, water-dispersible pigment composition comprising the steps of:
- forming a homogeneous mixture comprising milled or homogenized pigment, water and, by weight of the pigment, (a) from 15 to 45% of a nonionic dispersing agent selected from the group consisting of polyether alcohols, alkylene oxide-alkylene diamine block copolymers, polyoxyethylene glycol esters and polyoxyethylene glycerol esters, (b) from 10 to about 67% of at least one water-dispersible nonionic polymer selected from the group consisting of (1) an at least partially hydrolyzed polymer of vinyl acetate and (2) a polymer of an N-vinyl pyrrolidone and (c) from 0 to 40% of a nonionic colloid;
- and removing the water from said mixture until a dry composition is obtained, the total amount of dispersing agent, polymer and colloid being from 20 to 45% by weight of the dry composition.
A process for preparing a dry, water-dispersible pigment composition comprising the steps of:
- (a) milling or homogenizing pigment in water in the presence of from 15 to 45% by weight of the pigment of a nonionic dispersing agent selected from the group consisting of polyether alcohols, alkylene oxide-alkylene diamine block polymers, polyoxyethylene glycol esters and polyoxyethylene glycerol esters to form an aqueous pigment dispersion;
- (b) mixing said pigment dispersion with from 10 to about 67% by weight of the pigment of at least one water-dispersible nonionic polymer selected from the group consisting of (1) an at least partially hydrolyzed polymer of vinyl acetate and (2) a polymer of an N-vinyl pyrrolidone, and from 0 to about 40% by weight of the pigment of a nonionic colloid until a homogeneous mixture is formed;
- and
- (c) removing the water from said mixture until a dry composition is obtained, the total amount of dispersing agent, polymer and colloid being from 20 to 45% by weight of the dry composition.
A dry, water-dispersible pigment composition exhibiting good flocculation resistance and developing upon dispersion in aqueous systems good strength and color values, said composition comprising from 55 to 80% of pigment and from 45 to 20% of a nonionic material comprising, based on the weight of the pigment, from 15 to 45% of a nonionic dispersing agent selected from the group consisting of polyether alcohols, alkylene oxide-alkylene diamine block polymers, polyoxyethylene glycol esters and polyoxyethylene glycerol esters, from 10 to about 67% of at least one water-dispersible nonionic polymer selected from the group consisting of (1) an at least partially hydrolyzed polymer of vinyl acetate and (2) a polymer of an N-vinyl pyrrolidone, and from 0 to 40% of a nonionic colloid.
Dependencies are inferred from the claim text.