# US 9,518,192 B2 · Process for improving hiding efficiency in pigmented paints

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- Number: US 9,518,192 B2
- Document ID: US9518192B2
- Status: Granted
- Kind: B2
- Application number: 14/131,071
- Filed: 2011-07-05
- Published: 2015-01-22
- Granted: 2016-12-13
- Earliest claimed: 2011-07-05
- Assignees: Rohm and Haas Company
- Applicants: James C. Bohling; Deborah G. Fradkin; Wei Gao; John W. Hook, III; Tao Wang
- Inventors: James C. Bohling; Deborah G. Fradkin; Wei Gao; John W. Hook, III; Tao Wang; Tao Wang
- Web page: https://patentgrep.com/patent/US9518192B2

## CPC

- C09D 133/08: Homopolymers or copolymers of acrylic acid esters
- C08K 3/20: Oxides; Hydroxides {(graphene oxides C08K3/042)}
- C08K 3/22: of metals
- C09C 1/3676: {Treatment with macro-molecular organic compounds}
- C09D 5/028: {Pigments; Filters}
- C09D 7/45: Anti-settling agents
- C09D 7/61: inorganic
- C09D 7/80: Processes for incorporating ingredients
- C09D 135/06: Copolymers with vinyl aromatic monomers
- C01P 2004/62: Submicrometer sized, i.e. from 0.1-1 micrometer
- C08K 2003/2241: {Titanium dioxide}
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C09C: TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES (treatment of materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone C04B14/00, C04B18/00, C04B20/00); PREPARATION OF CARBON BLACK {; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS}
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

The present invention relates to a process comprising the steps of a) contacting an aqueous dispersion of a TiO2 slurry containing adsorbing dispersant with an adsorbing latex to form a mixture, wherein the pH of the mixture of the TiO2 slurry and adsorbing latex are sufficiently high to inhibit interaction between the TiO2 and the adsorbing latex; then b) lowering the pH of the mixture of step a) sufficiently to promote interaction between the TiO2 and the adsorbing latex, thereby forming a composite. The process of the present invention provides for improved hiding and reduced grit for coatings compositions.

## Claims

### Claim 1

A process comprising the steps of:
a) contacting an aqueous dispersion of a TiO2 slurry containing adsorbing dispersant with an adsorbing latex comprising structural units of a phosphorus acid monomer to form a mixture, wherein the pH of the mixture of the TiO2 slurry and the adsorbing latex is maintained at about 10 to 12 for a time in the range of 10 minutes to 24 hours to inhibit interaction between the TiO2 and the adsorbing latex; then
b) lowering the pH of the mixture of step a) to promote interaction between the TiO2 and the adsorbing latex, thereby forming a composite; wherein prior step to step a) the pH of the TiO2 slurry is raised from about 8 to 9 to about 10 to 12.

### Claim 2 (depends on 1)

The process of claim 1 wherein the pH of the TiO2 slurry is raised with an alkanol amine.

### Claim 3 (depends on 1)

The process of claim 1 which further includes the step of formulating the composite into a paint composition.

### Claim 4 (depends on 1)

The process of claim 1 which further includes the step of mixing the composite with an additive selected from the group consisting of rheology modifiers, pigments, extenders, binders dispersants, defoamers, preservatives, biocides, flow agents, and leveling agent, and combinations thereof.

### Claim 5

A process comprising the steps of:
a) contacting an aqueous dispersion of a TiO2 slurry containing adsorbing dispersant with an adsorbing latex comprising structural units of a phosphorus acid monomer to form a mixture, wherein the pH of the mixture of the TiO2 slurry and the adsorbing latex is maintained at about 10 to 12 for a time in the range of 10 minutes to 24 hours to inhibit interaction between the TiO2 and the adsorbing latex; then
b) lowering the pH of the mixture of step a) to a range of from 8.5 to 9 to promote interaction between the TiO2 and the adsorbing latex, thereby forming a composite wherein prior step to step a) the pH of the TiO2 slurry is raised from about 8 to 9 to about 10 to 12.

### Claim 6 (depends on 5)

The process of claim 5 wherein the pH of the TiO2 slurry is raised with an alkanol amine.

### Claim 7 (depends on 5)

The process of claim 5 which further includes the step of formulating the composite into a paint composition.

### Claim 8 (depends on 5)

The process of claim 5 which further includes the step of mixing the composite with an additive selected from the group consisting of rheology modifiers, pigments, extenders, binders dispersants, defoamers, preservatives, biocides, flow agents, and leveling agent, and combinations thereof.