Method for improving rheological properties of an aqueous pigment slurry and a dispersion agent

Patent metadata

Field	Value
Publication number	US-RE46649-E
Application number	US-201615142252-A
Country	US
Kind code	E1
Filing date	Apr 29, 2016
Priority date	Dec 18, 2008
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

The invention relates to a method for improving rheological properties of an aqueous pigment slurry. In the method dispersion agent is added to an aqueous phase of a slurry comprising pigment particles or to the aqueous phase into which the pigment particles are to be added. The dispersion agent comprises styrene acrylate copolymer. The invention also relates to a dispersion agent for a pigment slurry comprising a first component comprising styrene acrylate copolymer and a second component comprising a conventional dispersion agent, such as a straight-chain polyacrylate.

First claim

The invention claimed is:

1. A method for improving the rheological high shear properties of an aqueous pigment slurry comprising calcium carbonate, kaolin, calcinated kaolin, talc, titanium dioxide, gypsum, chalk, satine white, barium sulphate, sodium aluminium silicate, aluminium hydroxide or any of their mixture, the aqueous pigment slurry having a solids content of about 68%, the method comprising adding a dispersion agent to an aqueous phase of a slurry comprising pigment particles or to the aqueous phase into which the pigment particles are to be added, the dispersion agent comprising styrene acrylate copolymer, wherein the styrene acrylate copolymer comprises starch, wherein the dispersion agent improves the rheological properties of the slurry, and wherein the dispersion agent decreases the high shear viscosity of the slurry, and further comprising adding also a conventional dispersion agent comprising straight-chain polyacrylate to the aqueous phase.

2. The method according to claim 1 , comprising adding at least 0.1 parts dispersion agent comprising styrene acrylate copolymer per 100 parts pigment in the slurry.

3. The method according to claim 1 , wherein the dispersion agent comprising the styrene acrylate copolymer is used in the form of an aqueous polymer dispersion having a solids content of 10-50%.

4. The method according to claim 1 , wherein the proportion first component: second component of the dispersion agent:the conventional dispersion agent is in the range of 50:50-99:1.

5. A dispersion agent for a pigment slurry, where the pigment slurry comprises calcium carbonate, kaolin, calcinated kaolin, talc, titanium dioxide, gypsum, chalk, satine white, barium sulphate, sodium aluminium silicate, aluminium hydroxide or any of their mixture, comprising a first component comprising styrene acrylate copolymer wherein the styrene acrylate copolymer decreases the high shear viscosity of the slurry, wherein the styrene acrylate copolymer comprises starch, the aqueous pigment slurry having a solids content of about 68%, a second component comprising a conventional dispersion agent comprising straight-chain polyacrylate.

6. The dispersion agent according to claim 5 , wherein the proportion of first component:second component is in the range of 50:50-99:1.

7. The dispersion agent according to claim 5 , wherein the mean particle size of the styrene acrylate copolymer is 20-300 nm.

Assignees

• Kemira Oyj

Inventors

• Aarni Esko
• Heiska Perttu
• Huhtala Kimmo

Classifications

• D21H19/58 Primary

  Polymers or oligomers of diolefins, aromatic vinyl monomers or unsaturated acids or derivatives thereof · CPC title

• C09D17/001

  in aqueous medium (C09D17/003, C09D17/004 take precedence) · CPC title

• C09D17/004 Primary

  containing an inorganic pigment · CPC title

• C08K2003/265

  Calcium, strontium or barium carbonate · CPC title

• C09D7/02

  Chemistry & Metallurgy · mapped topic