Pigments for paper coating compositions
US5882396A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 30, 1996 |
| Grant date | Mar 16, 1999 |
| Priority date | — |
| Expiry date | Oct 30, 2016 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21H19/40
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
An inorganic particulate material suitable for use as a pigment material in a paper coating composition has a particle size distribution which when represented as a graph of percentage of weight of particles having an equivalent spherical diameter (esd) of given size versus particle esd expressed in microns and plotted on a logarithmic base 10 scale has the following features: (a) a first peak at the coarse particle size and a second peak at a finer particle size and a dip or trough between the first and second peaks; (b) the mean particle size x.sub.1 of the particles making up the first peak being 2 to 4 microns; (c) the relationship between the first and second peaks being such that the value of the mean particle size x.sub.2 of the particles making up the second peak is separated in the particle size distribution graph from the value of x.sub.1 by at least 0.5; and (d) the minimum of the dip or trough is at a given particle esd dimension of between 0.5 and 5 microns. The material may be obtained by mixing in suitable amounts a coarse pigment material and a fine pigment material having individually the appropriate particle size distributions. The coarse and fine pigments may be …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.