Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1990-07-12
1993-04-27
Seidleck, James J.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525 88, 525 92, 525 93, 525 94, 525 95, 525 96, 525 98, 525285, 525904, 525914, C08F29704, C08L 5302
Patent
active
052063011
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention relates to a special thermoplastic block copolymer having excellent weather resistance, impact resistance and coatability and suited for rubber applications and improvement of resins in impact resistance and coatability, as well as to a composition comprising said copolymer.
2. Background Art
Thermoplastic elastomers are used as an impact resistance improver for polypropylene and polystyrene. As the thermoplastic elastomer suited for this application, there have hitherto been known block copolymers composed of a polystyrene (A) and a polybutadiene (B) and represented by the general formula A--B--A, B--A--B--A or (A--B).sub.n X (X is a coupling agent residue). In order to improve the weather resistance and heat resistance of these thermoplastic elastomers, there are known a hydrogenated polybutadiene obtained by hydrogenating a block copolymer comprising a polybutadiene having a 1,2-structure adjusted to 30-50% and a polystyrene. However, when said hydrogenated polybutadiene is used as an improver for plastics such as polypropylene resin, polystyrene and the like, low temperature impact resistance of the resultant composition is low because the glass transition temperature of its elastomer block portion becomes high. It is also known that a hydrogenated block copolymer obtained by hydrogenating a block copolymer comprising a polybutadiene block high 1,4 structure and a polybutadiene polymer block high 1,2 structure, also shows dynamic properties of thermoplastic elastomer. However, when used as an improver for .alpha.-olefin resins, coatability is poor.
DISCLOSURE OF THE INVENTION
Impact resistance improvers for polypropylene, polystyrene, etc. are required to have low temperature impact resistance, weather resistance and coatability. The impact resistance improvers of thermoplastic elastomer type conventionally used, however, do not fully satisfy the above requirements; therefore, the development of a new impact resistance improver has been desired. The object of the present invention is to provide a novel thermoplastic elastomer satisfying the above requirements.
The present inventors made extensive research to solve the above-mentioned problems of the prior art. As a result, it was found that the above object can be attained by a hydrogenated block copolymer obtained by hydrogenating a block copolymer comprising a polymer block A composed mainly of a vinyl aromatic compound, a polybutadiene polymer block B medium in 1,2-vinyl structure and a polybutadiene polymer block C low 1,2-vinyl structure. The present invention has been completed based on the above finding.
BRIEF EXPLANATION OF DRAWINGS
FIG. 1 shows the DSC curves of the hydrogenated block copolymers obtained in Examples 1 and 2 and Comparative Example 1.
FIG. 2 shows the stress-strain curves of the sheets obtained by molding only the hydrogenated block copolymers obtained in Examples 1 and 2 and Comparative Example 1.
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention provides a hydrogenated block copolymer having a number-average molecular weight of 40,000-700,000, obtained by hydrogenating at least 80% of the olefinic bonds of an unhydrogenated block copolymer having in the molecule at least one each of
a polymer block A composed of 90% by weight or more of a vinyl aromatic compound,
a polybutadiene polymer block B having a 1,2-vinyl structure of 30-70%, and
a polybutadiene polymer block C having a 1,2-vinyl structure of less than 30%, is 10-50% by weight, the content of the polymer block B is 30-80% by weight, and the content of the polymer block C is 5-30% by weight, or a unit of said block copolymer is bonded, via a coupling agent residue, to a polymer unit consisting of at least one polymer block of the A, B and C and thereby the polymer molecular chain is extended or branched.
The hydrogenated block copolymer comprises, as essential components, at least one each of the polymer blocks A, B and C. The block copolymer having the simplest structure includes a block copol
REFERENCES:
patent: 3251905 (1966-05-01), Zelinski
patent: 3281383 (1966-10-01), Zelinski et al.
patent: 3639517 (1972-02-01), Kitchen et al.
patent: 3670054 (1972-06-01), De La Mare et al.
patent: 4077893 (1978-03-01), Kiovsky
patent: 4163765 (1979-08-01), Moczygemba
patent: 4628072 (1986-12-01), Shiraki et al.
patent: 4814386 (1989-03-01), Hellermann et al.
patent: 4939208 (1990-07-01), Langa et al.
Hattori Iwakazu
Oshima Noboru
Shibata Tooru
Takeuchi Yasuo
Jagannathan Vasu S.
Japan Synthetic Rubber Co. Ltd.
Seidleck James J.
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