Polymer-encapsulated pigment particle
AssigneeSwimc LLC
InventorJason Ness
Life of this patent
Estimating the term…
Abstract
A polymer-encapsulated pigment dispersion is prepared from a mixture of (a) a carrier; (b) pigment particles; and (c) a polymeric dispersing agent having a polymer backbone, and an alkali-swellable copolymer component. The dispersing agent may provide efficient pigment wetting and dispersion using relatively low and thus economical dispersant amounts, and subsequently enable formation of polymer-encapsulating pigment dispersions that, when used in coatings, provide good opacity and good hiding characteristics, especially in titanium dioxide-containing coating compositions.
Claims23
A pigment grind dispersion comprising a mixture of:
- a) a carrier comprising water;
- b) opacifying inorganic pigment particles having an index of refraction of at least 1.8 and being at least partially encapsulated by at least one polymer layer;
- c) alkali;
- and
- d) a polymeric dispersing agent having one or more alkali-swollen or alkali-dissolved copolymer components, wherein the alkali-swollen or alkali-dissolved component is derived from ingredients including one or more ethylenically unsaturated hydrophilic monomers that include a hydroxyl group, acidic group, amino group or ethylene oxide group, and the polymeric dispersing agent is present at about 0.1 to about 25 wt. % of the opacifying pigment particle weight.
A method for making a polymer-encapsulated pigment dispersion, which method comprises:
- a) forming a dispersion of a carrier comprising water;
- opacifying inorganic pigment particles having an index of refraction of at least 1.8;
- alkali;
- and a polymeric dispersing agent having one or more alkali-swollen or alkali-dissolved copolymer components, wherein the alkali-swollen or alkali-dissolved component is derived from ingredients including one or more ethylenically unsaturated hydrophilic monomers that include a hydroxyl group, acidic group, amino group or ethylene oxide group, and the polymeric dispersing agent is present at about 0.1 to about 25 wt. % of the opacifying pigment particle weight;
- b) including in or adding to the dispersion one or more ethylenically unsaturated monomers and a free-radical initiator;
- and
- c) polymerizing the ethylenically unsaturated monomers to at least partially encapsulate the pigment particles with at least one polymer layer.
A coating composition comprising a dispersion of:
- a) a carrier comprising water;
- b) opacifying inorganic pigment particles having an index of refraction of at least 1.8, the pigment particles being at least partially encapsulated by at least one polymer layer;
- c) alkali;
- d) a polymeric dispersing agent having one or more alkali-swollen or alkali-dissolved copolymer components, wherein the alkali-swollen or alkali-dissolved component is derived from ingredients including one or more ethylenically unsaturated hydrophilic monomers that include a hydroxyl group, acidic group, amino group or ethylene oxide group, and the polymeric dispersing agent is present at about 0.1 to about 25 wt. % of the opacifying pigment particle weight;
- and
- e) one or both of:
- i) a film-forming binder containing a polymer other than the polymer layer polymer;
- or
- ii) one or more thickeners, rheology modifiers, surfactants or coalescents.
Dependencies are inferred from the claim text.