Sequential heteropolymer dispersion and a particulate material obtainable therefrom, useful in coating compositions as a thickening and/or opacifying agent
US4427836A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 25, 1982 |
| Grant date | Jan 24, 1984 |
| Priority date | — |
| Expiry date | Feb 25, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S525/902
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The present invention is concerned with the production and use of water-insoluble particulate heteropolymers made by sequential emulsion polymerization in dispersed particles of which a "core" of a polymeric acid is at least partially encased in a "sheath" polymer that is permeable to a volatile base, such as ammonia or an organic amine, adapted to cause swelling of the core by neutralization. The aqueous dispersion of the acid-containing core/sheath particles is useful in making water-base coating compositions wherein it may serve as an opacifying agent when a volatile base is used to at least partially (to a pH of at least 6) neutralize the heteropolymer, microvoids being formed in cores of the swollen particles in the film during the drying thereof. Thus, the heteropolymer dispersion can serve as an opacifying agent in coating compositions, such as water-base paints, as a supplement or replacement of part or all of the pigmentary material or extenders that would otherwise be used in such coating compositions. For convenience of description herein, the terms "core", "sheath", and "core/sheath polymr" are frequently used to refer to the distinct functional components of the indivi…
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