The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 20, 1990
Filed:
Jul. 26, 1988
Mune Iwamoto, Yokohama, JP;
Norifumi Ito, Kamakura, JP;
Kazuo Sugazaki, Yokohama, JP;
Tetsuyuki Matsubara, Yokohama, JP;
Toshihiko Ando, Yokohama, JP;
Yasuo Furuta, Hiratsuka, JP;
Mitsui Toatsu Chemicals, Inc., Tokyo, JP;
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.