Colorless, non-toxic, stabilized aqueous solution of a C1-C5 alkyl vinyl ether and maleic acid copolymers
US5449715A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 1993 |
| Grant date | Sep 12, 1995 |
| Priority date | — |
| Expiry date | Jul 15, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08K5/175
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
What is provided herein is a colorless, stabilized aqueous solution of a C.sub.1 -C.sub.5 alkyl vinyl ether and maleic acid copolymer which includes about 100 to 1,000 ppm of an additive mixture of (a) about 30-70% by weight of ethylenediaminetetraacetic acid (EDTA) or its salts, such as the disodium, trisodium, tetrasodium or disodium-calcium salts, and (b) about 30-70% by weight of a secondary additive which is an organic antioxidant and/or free radical scavenger selected from t-butylhydroquinone, propyl gallate, butylated hydroxy-anisole (BHA), butylated hydroxy-toluene (BHT), 4-hydroxymethyl-2,6-di-tert-butylphenol, 2,4,5-trihydroxy-butyrophenone (THBP) and N,N-diethylhydroxylamine, said stabilized solution exhibiting a retention of at least about 85-90% of its original viscosity after 3 months. Preferably, the solution is prepared by hydrolyzing the corresponding anhydride in the presence of said additive mixture.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.