Substantially homogeneous copolymers of acrylic or methacrylic acid and maleic acid
US4710537A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 11, 1985 |
| Grant date | Dec 1, 1987 |
| Priority date | — |
| Expiry date | Oct 11, 2005 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F222/04
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Substantially homogeneous acrylate/maleate copolymers of number average molecular weight of 500 to 5000 are prepared by copolymerizing 35 to 65 mole percent acrylic or methacrylic acid with 65 to 35 mole percent maleic anhydride at 80.degree. to 150.degree. C. in the presence of a polymerization initiator and a chain-transfer solvent such that both the monomers and the formed polymer remain in solution and the mole ratio of the acrylic or methacrylic acid monomer to the maleic anhydride monomer in the solvent is maintained below about 0.2 throughout the polymerization. The copolymers in hydrolyzed form are employed at a level of from about 0.1 to 100 ppm for prevention of alkaline calcium and magnesium scale formation, such as during seawater evaporative desalination.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.