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:
Feb. 22, 2022
Filed:
Jul. 20, 2018
Jsp Corporation, Tokyo, JP;
Kenji Haraguchi, Yokkaichi, JP;
Jumpei Goto, Yokkaichi, JP;
JSP Corporation, Tokyo, JP;
Abstract
The present invention relates to a styrene-based resin having a weight average molecular weight Mw' as determined by the GPC-MALS method of 1,000,000 or more and 5,000,000 or less, a degree of long-chain branching of 0.2 or more per 1,000 styrene units, and a tetrahydrofuran-insoluble matter of 0.1% by weight or less (including 0), the styrene-based resin being free from a component derived from a polyfunctional monomer in a molecular chain thereof. In a method for producing this styrene-based resin, in an impregnation step of adding a polymerization initiator and a styrene monomer in an aqueous medium, thereby impregnating the polymerization initiator and the styrene monomer in the seed particle at a temperature at which polymerization of the styrene monomer does not substantially proceed, the amount of the styrene monomer is 20 to 200 parts by weight based on 100 parts by weight of the seed particle; and in an additional impregnation polymerization step of graft polymerizing the styrene monomer on the styrene-based resin, the addition amount of the styrene monomer is 50 to 700 parts by weight based on 100 parts by weight of the seed particle, and the content of the styrene monomer in the seed particle is held at 10% by weight or less.