Anionically-polymerized-rubber-modified styrene copolymers
US4972024A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 1988 |
| Grant date | Nov 20, 1990 |
| Priority date | — |
| Expiry date | Jul 26, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F297/04
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Disclosed herein is a rubber-modified styrene copolymer which contains as an impact strength modifier a rubbery polymer having a viscosity of 2-250 centipoises as measured at 25.degree. C. as a 5 wt. % styrene solution and a styrene insoluble content lower than 0.1 wt. %, produced by anionic polymerization and dispersed in a continuous phase of a styrene-acrylonitrile copolymer. The rubbery polymer contains small particles of the same styrene-acrylonitrile copolymer occluded in the form of cells. The areas of particles in each of which the maximum cell diameter is smaller than 0.1 .mu.m are at least 40% of the area of all the particles of the rubbery polymer and the volume average particle size of these particles is 0.1-0.4 .mu.m. The weight ratio of the monomers in the styrene-acrylonitrile copolymer is 90/10.gtoreq.styrene/acrylonitrile.gtoreq.55/45. Per 100 parts by weight of the copolymer, the proportions of polymers having a molecular weight greater than 1,000,000 is smaller than 0.5 part by weight while the proportion of polymers having a molecular weight greater than 1,200,000 is smaller than 0.01 part by weight.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.