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. 03, 1987
Filed:
Mar. 24, 1986
Alonzo G Kitchen, Bartlesville, OK (US);
Phillips Petroleum Company, Bartlesville, OK (US);
Abstract
Sequential charging of initiator and monomers in a multistage solution polymerization process involving conjugated diene and monovinylaromatic monomers wherein the initial and final charges are monovinylaromatic monomer results in the production of polymodal linear block copolymers with terminal resinous blocks. A typical 6-stage charge sequence is as follows: stage 1: (S.sub.i); stage 2: (S.sub.i); stage 3: (B); stage 4: (S.sub.i); stage 5: (B) and stage 6: (S) wherein (S.sub.i) is monovinylaromatic monomer and initiator, (B) is conjugated diene monomer and (S) is monovinylaromatic monomer. At each stage, polymerization is allowed to continue until no free monomer is present. The polymodal block copolymer products comprise high, medium and low molecular weight species designated, respectively, as S.sub.1 -S.sub.2 -B.sub.1 -S.sub.3 -B.sub.2 -S.sub.4 ; S.sub.2 -B.sub.1 -S.sub.3 -B.sub.2 -S.sub.4 ; and S.sub.3 -B.sub.2 -S.sub.4 wherein S.sub.1, S.sub.2, S.sub.3 and S.sub.4 represent, respectively, polyvinylaromatic blocks resulting from polymerization of the first, second, third and fourth charges of monovinylaromatc monomer (stages 1,2,4 and 6); B.sub.1 represents a polydiene block resulting from polymerization of the first charge of conjugated diene monomer (stage 3); and B.sub.2 represents a polydiene block resulting from polymerization of the second charge of conjugated diene monomer (stage 5). The subject copolymers can be fabricated into sheets and molded objects possessing little color, a high degree of transparency and excellent impact resistance. These fabricated products do not craze on being impacted.