Process for preventing segregation of a component in a mixture of powders
US3974089A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 20, 1974 |
| Grant date | Aug 10, 1976 |
| Priority date | — |
| Expiry date | Sep 20, 1994 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/90
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A method is disclosed for preventing segregation of particles within a finely divided powder having disparate particle size ranges, compositions or densities. The method includes working the powder with a minute amount, preferably less than about 1% by weight of the powder, of a finely divided fibrillatable polytetrafluoroethylene resin (hereinafter referred to as PTFE) to form a mixture with the powder. The PTFE resin may be added to the powder as a colloidal aqueous dispersion or as a fine powder obtained by coagulation of the colloidal dispersion. Whichever form is used, the PTFE is intimately mixed with the finely divided powder to form a dry mixture. Alternatively, the PTFE resin may be blended with the powder in a wet treatment to facilitate the homogenous dispersion of the resin. In any event, the mixture of resin and powder is worked either in the wet state, preferably as a paste, or as a dry blend, using a masticating or kneading action to fibrillate the PTFE. Sufficient working is carried out to produce a random network of PTFE fibers sufficient to loosely entrap the powdery material and to prevent segregation thereof.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.