Preparation and use of high brightness kaolin pigments
US6514333B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 9, 2000 |
| Grant date | Feb 4, 2003 |
| Priority date | — |
| Expiry date | Nov 9, 2020 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21H19/40
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A novel clay pigment, the manufacture thereof and the use of the pigment in the coating of lightweight groundwood paper are disclosed. The kaolin clay particles initially have a shape factor between less than 10 and a particle size distribution where between 30 to 60% by weight is less than 2 microns and 20% by weight is less than 0.25 micron e.s.d. This clay is subjected to attrition grinding to produce clay particles having a shape factor between 13 and 18 and then classified to produce a particle size distribution where 80 to 90% by weight are less than 2 microns and 20% by weight are less than 0.25 micron. These pigments have a G.E. brightness ranging from 88 to 92; are deficient in ultra-fine particles; are fluid at a high solids concentration greater than 70%, and have a low shear Brookfield viscosity below 500 cps and a high shear Hercules viscosity of 18 dyne-cm above 200 rpm when using an “A” bob.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.