Claims
- 1. A block copolymer mixture of conjugated diene and vinylaromatic hydrocarbon produced by the following two step polymerization:
- a first step (A) for preparing (a) a living block copolymer having the following general formula:
- --A--B).sub.n+1 Li or A--B--A).sub.n Li,
- where A is a polymer block consisting mainly of conjugated diene, B a polymer block consisting mainly of vinylaromatic hydrocarbons, and n is an integer of 1 or more, by polymerizing a conjugated diene and a vinylaromatic hydrocarbon, in a ratio by weight of vinylaromatic hydrocarbon to conjugated diene of 60/40 or less, the monomers being employed in an amount of 1 to 80% by weight of the total monomers to be used in the two polymerization steps, using an organomonolithium compound as a catalyst and a solvent consisting mainly of aliphatic hydrocarbon, the polymers not being inactivated with an inactivating agent, and
- a second step (B) of (1) preparing (b) a vinylaromatic hydrocarbon polymer and (2) simultaneously extending block copolymer chains obtained in said step (A), by adding to the living block copolymer obtained in said step (A), a vinylaromatic hydrocarbon, the monomer being employed in an amount of 99 to 20% by weight of total monomers to be used in the two polymerization steps, and adding an organolithium compound as a catalyst and a solvent consisting mainly of an aliphatic hydrocarbon, and polymerizing the said monomer to simultaneously obtain polymer (b) by the freshly added organolithium compound and an ultimate block copolymer by extending the chains of the living block copolymer obtained in said step (A), thereby obtaining a block copolymer mixture;
- the block copolymer mixture being characterized in that the structure of the polymer (b) obtained in the second polymerization step (B) alone is substantially the same as the structure of the portion of the ultimate block copolymer obtained by extending, in the second step, the chains of the living block copolymer obtained in the first polymerization step (A), and the block copolymer mixture having a ratio of the vinylaromatic hydrocarbon content, in weight percent, of the ultimate block copolymer to the vinylaromatic hydrocarbon content, in weight percent, of the polymer (b) of at least 1/1.8, and having a ratio of vinylaromatic hydrocarbon content to conjugated diene content of 60/40 to 95/5.
Priority Claims (2)
Number |
Date |
Country |
Kind |
49-105970 |
Sep 1974 |
JPX |
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50-27064 |
Mar 1975 |
JPX |
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Parent Case Info
This is a continuation of application Ser. No. 58,940, filed July 19, 1979, abandoned and which is a division of application Ser. No. 609,684, filed Sept. 2, 1975, now U.S. Pat. No. 4,208,356.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
4073831 |
Tabana |
Feb 1978 |
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Divisions (1)
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Number |
Date |
Country |
Parent |
609684 |
Sep 1975 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
58940 |
Jul 1979 |
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