Polydiorganosiloxane latex
US4568718A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 25, 1984 |
| Grant date | Feb 4, 1986 |
| Priority date | — |
| Expiry date | Jun 25, 2004 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G77/70
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
This invention is a method of producing an aqueous latex of crosslinked polydiorganosiloxane. The latex yields an elastomer upon removal of the water. The latex is prepared by homogenizing a mixture of hydroxyl endblocked polydiorganosiloxane; a silane of the formula R.sub.a 'Si(OR.sup.3).sub.4-a where R' is a monovalent hydrocarbon radical of up to 12 carbon atoms, R.sup.3 is an alkyl radical of 1 to 6 carbon atoms, a partial hydrolyzate, or mixture of silane and hydrolyzate, and a is 0 or 1; a surface active anionic catalyst of the formulae R.sup.2 C.sub.6 H.sub.4 SO.sub.3 H wherein R.sup.2 is a monovalent hydrocarbon radical of at least 6 carbon atoms, R.sup.2 OSO.sub.2 OH, or ##STR1## wherein R.sup.4 is H or R.sup.2 ; and water. The resulting emulsion is maintained at a temperature of 15.degree. to 30.degree. C. for at least 5 hours at a pH of less than 5 until a crosslinked polymer is formed, then this emulsion is admixed with base to a pH of greater than 7. The resulting emulsion is reinforced by adding greater than 1 part by weight of colloidal silica sol or silsesquioxane to yield a latex. Removal of water from the latex results in a reinforced elastomer. This method yields…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.