Sag control of high solid polyurethane clearcoats by urea thixotrope/acrylic microgel systems
US4540734A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 30, 1984 |
| Grant date | Sep 10, 1985 |
| Priority date | — |
| Expiry date | Jul 30, 2004 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G18/10
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Novel, high solids urethane clearcoat compositions having improved flow characteristics by the incorporation of a flow control system composed of urea thixotrope/acrylic microgel additives. The urea thixotrope constituent is prepared by reacting a polyether polyol with a stoichiometric excess of a saturated cyclic aliphatic polyisocyanate to produce isocyanate-terminated prepolymers. These prepolymers are then modified by reaction with an ethanolamine to form urea end-capped thixotropes which are compatible in structure with any urethane clearcoat system. A combination of one of these urea thixotropes and a polymethyl methacrylate microgel of fine particle size is used effectively to reduce sagging of high solids urethane clearcoat systems. In fact, the combination of the two components produces a synergistic effect which is greater than that expected from any one of the components in the flow control system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.