公开(公告)号：ES2041250T3

公开(公告)日：1993-11-16

申请号：ES87104253

申请日：1987-03-23

Applicant: PHILLIPS PETROLEUM COMPANY

Inventor： KITCHEN, ALONZO GENE ,  SZALLA, FRANK JOHN

IPC: C08F4/08 ,  C08F4/42 ,  C08F4/48 ,  C08F297/04 ,  C08L53/00 ,  C08L53/02

Abstract: Sequential charging of initiator and monomers in a multistage solution polymerization process involving conjugated diene and monovinylaromatic monomers wherein the final charge is a mixture of these monomers results in the production of resinous polymodal linear block copolymers each with a terminal tapered block. A typical 5-stage charge sequence is as follows: Stage 1: (Si); Stage 2: (Si); Stage 3: (B); Stage 4: (Si); Stage 5: (S+B) wherein (Si) is monovinylaromatic monomer and initiator; (B) is conjugated diene monomer and (S+B) is monovinylaromatic monomer and conjugated diene monomer. At each stage, polymerization is allowed to continue until no free monomer is present. The trimodal block copolymer products comprise high, medium and low molecular weight species designated, respectively, as S1-S2-B1-S3-B2->S4; S2-B1-S3-B2->S4; and S3-B2->S4 wherein S1, S2 and S3 represent, respectively, polyvinylaromatic blocks resulting from polymerization of the first, second and third charges of monovinylaromatic monomer (stages 1,2 and 4); B1 represents a polydiene block resulting from polymerization of the first charge of conjugated diene monomer (stage 3); and B2->S4 represents a terminal tapered copolymer block resulting from polymerization of the conjugated diene and monovinylaromatic monomers (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.