Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1996-06-14
1998-01-27
Morgan, Kriellion S.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
523207, C08K 904
Patent
active
057123306
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a styrenic resin pellet and a molding produced therefrom. More particularly, it pertains to a styrenic resin pellet and a molding produced therefrom that are greatly improved in impact resistance as well as practical characteristics at elevated temperatures without losing the excellent heat resistance and high mechanical strength that are inherent in a styrenic resin having syndiotactic configuration.
BACKGROUND ART
Though a styrenic resin has heretofore been widely used in a variety of fields as a general-purpose resin, it has suffered the serious disadvantage of its inferior impact resistance in general. In order to improve the impact resistance of a styrenic polymer, there is industrially produced a so-called rubbery modified styrenic polymer, that is, a substantial mixture of a rubbery polymer/styrene graft copolymer and polystyrene in which a part of styrene is graft-polymerized onto a rubbery polymer and the remainder thereof constitutes polystyrene by a method in which styrene is blended with a rubbery polymer or a method in which styrene is polymerized in the presence of a rubbery polymer.
In addition, Japanese Patent Application Laid-Open No. 247292/1993 discloses that a styrenic resin composition is excellent in impact resistance and release properties from a hot mold, said composition comprising a styrenic polymer having high degree of syndiotactic configuration, a rubbery elastomer having a product of weight-average molecular weight and styrenic monomer unit content being at least 30,000 and a filler such as glass fiber. The above-mentioned styrenic polymer, although sufficiently improved in release properties from a hot mold, is not sufficiently improved in general physical-properties such as impact resistance and heat resistance, and in particular is inferior in practical characteristics such as creep at a high temperature higher than the glass transition temperature and vibrational fatigue.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide a styrenic resin pellet usable as the raw material for a molding which is improved in general physical-properties such as impact resistance and heat resistance, and is excellent in practical characteristics such as tensile creep at a high temperature higher than the glass transition temperature and vibrational fatigue at a high temperature, while preserving the excellent moldability of the pellet.
As a result of intensive research and investigation accumulated by the present inventors in order to develop a styrenic resin pellet having favorable properties as mentioned above, the foregoing disadvantage has turned out to be caused by the fact that since the aforesaid conventional styrenic resion composition is prepared only by melt-kneading each of the components, glass fiber as a filler incorporated in the composition is broken off at the time of kneading. As a result of further research continued by the present inventors, it has been found that the above-mentioned object can be achieved by impregnating glass fiber with a styrenic polymer having syndiotactic configuration and containing a polar group and equalizing the lengths of a styrenic resin pellet and the glass fiber thus treated. The present invention has been accomplished by the above-mentioned finding and information.
Specifically, the present invention provides a styrenic resin pellet having a length in the range of 2 to 100 mm, preferably 5 to 50 mm which comprises a (A) styrenic polymer having syndiotactic configuration and containing a polar group; and at least 10% by weight, preferably 30 to 80% by weight of a (B) glass fiber which is surface-treated with a coupling agent, said glass fiber being impregnated with said styrenic polymer, and having a length equal to the length of said pellet.
The present invention further provides a styrenic resin pellet having a length in the range of 2 to 100 mm, preferably 5 to 50 mm which comprises a (C) styrenic polymer having syndiotactic configuration; a (D) rubbery elast
REFERENCES:
patent: 3650810 (1972-03-01), Marzocchi
patent: 3775163 (1973-11-01), Marzocchi
patent: 4659752 (1987-04-01), Piret
Fukui Hiroki
Funayama Michio
Idemitsu Petrochemical Co. Ltd.
Morgan Kriellion S.
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