Method for hydrophobing gypsum
US5776245A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 4, 1997 |
| Grant date | Jul 7, 1998 |
| Priority date | — |
| Expiry date | Mar 4, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B2103/65
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method for preparing an aqueous gypsum mixture having hydrophobic additive substantially uniformly dispersed therein, which method comprises admixing in water gypsum, a silane of the general formula (RO).sub.3 SiR' or the general formula (RO).sub.2 SiRR' and non-emulsified polysiloxane of the general formula; ##STR1## wherein each R is the same or different and represents a hydrocarbon group having from one to eight carbon atoms, R' represents a lower alkyl group which is optionally substituted by an amino, amino-loweralkylene-amino or dialkylenetriamine group, and a has an average value of between 20 and 200. The silane is preferably N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and the polysiloxane preferably trimethyl end-blocked linear methylhydrogen polysiloxane. The method may further include adding surfactant. Also disclosed is a gypsum product which includes gypsum mixture prepared according to the above method.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.