Method for extending pigments
US5700319A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 28, 1995 |
| Grant date | Dec 23, 1997 |
| Priority date | — |
| Expiry date | Sep 28, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S106/04
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Unusually high loading levels of smectite minerals are found to provide excellent pigment spacing in aqueous-based coatings, as will enable desired improved hiding, thereby extending the pigment. The level of smectite used in accordance with the invention is sufficiently high that the high gelling efficiency smectites previously used as thixotropes would be inappropriate, and would yield viscosities so high as to render the aqueous coating composition lacking in desired flowability properties. Thus in accordance with the present invention, there is mixed with the aqueous carrier and pigment at least 0.5% by weight of the total composition, of a particulate water swellable smectite which has a gelling efficiency such as to display a 20 rpm Brookfield viscosity of less than 900 cps when subjected to the standard gelling test herein, with the amount of the smectite in the composition not exceeding that which would raise the viscosity of the composition above 110 Krebs Units (KU).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.