Chemically opening chrysotile asbestos and encapsulating
US3965284A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 19, 1973 |
| Grant date | Jun 22, 1976 |
| Priority date | — |
| Expiry date | Jan 19, 1993 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2998
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
Chrysotile asbestos is chemically opened into the individual fibrils by soluble vinylic polymer polyelectrolytes containing carboxylic acid groups in aqueous media. Polyacrylic acids, polymethacrylic acids, maleic anhydride polymers and water-soluble copolymers thereof are preferred polyelectrolytes and form stable colloidal dispersions. The polyelectrolytes are neutralized to alkaline pH with inorganic or organic bases, but preferably with basic vinylic monomers when complete encapsulation is desired. By a further aspect of the invention the polyelectrolyte-coated fibrils in aqueous dispersion are encapsulated by copolymerization with (a) a basic vinylic comonomer (used for pH control) such as dimethylaminoethyl methacrylate, t-butylaminoethyl methacrylate or a vinylpyridine; and (b) a non-basic vinylic comonomer such as styrene, divinylbenzene, vinyl chloride or fluoride, vinyl acetate, methyl methacrylate, ethyl acrylate, acrylonitrile, and methacrylonitrile. The encapsulated fibrils are advantageous for forming reinforced composites including laminates and foamed or cellular products.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.