Title: Prepn. of block polymers
Application Number: 85102259 Application Date: 1985.04.01
Publication Number: 1002132 Publication Date: 1986.08.06
Approval Pub. Date: Granted Pub. Date: 1987.12.02
International Classifi-cation: C08F297/04
Applicant(s) Name: Beijing Research Inst. of Yanshan Petrochemical Co Address:
Inventor(s) Name: Guo Wenli, Wang Dechong
Attorney & Agent:
Abstract:
     The SDS is block polymerized in the presence of n-butyl lithium or sec-butyl lithium as initiator and cyclohexane as solvent. In order to reduce the permanent set of SDS, during the first stage of polymerization it is added to styrene small amount of conjugated dieues, which is 0.01-5.0 wt% of the total butadiene, preferably 0.05-1.50%. The time of adding conjugated diene is 0.2-15 min. of the first stage of styrene polymerization, preferably at 0.5-6.0 min. SDS thus produced has permanent set less than 30% without any deficiency of other physical mechanical properties.
Time: 3