Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1995-06-26
1997-09-09
Hoke, Veronica P.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
523220, 524493, 524494, 524495, 524496, 524497, 524554, C08K 718, C08K 720
Patent
active
056657951
DESCRIPTION:
BRIEF SUMMARY
This application is the national stage application under 35 USC .sctn.371 of International Application No. PCT/JP94/00318, filed Feb. 28, 1994, which claims the priority of Japanese Patent Application No. 05-64743 filed Mar. 1, 1993, and Japanese Patent Application No. 05-164060, filed Jun. 8, 1993.
TECHNICAL FIELD
The present invention relates to resin compositions excellent in moldability and molded articles obtained therefrom which are excellent in dimensional stability and surface precision against environmental changes such as temperature and humidity.
BACKGROUND ART
Attempts to use resins as materials for precision molded articles have been increasingly made. However, since resins generally have a high linear expansion coefficient, they are apt to undergo dimensional change owing to change in environmental temperatures and furthermore, when molded into articles of thick wall, considerable shrinkage occurs, and thus, they have many problems as materials for precision molded articles.
Recently, thermoplastic norbornene resins excellent in heat resistance and moisture resistance have been noticed as molding materials in various fields. Thermoplastic norbornene resins can be precision molded and are superior in dimensional stability against change of humidity, but like other resins, have a high linear expansion coefficient. Therefore, they have problems in dimensional stability against temperature change and cannot be used as materials for precision molded articles used in an environment where temperatures are apt to change. Furthermore, even if precision molding is possible, shrink marks have sometimes been formed.
In order to decrease linear expansion coefficient and inhibit formation of shrink marks, it has been attempted to add inorganic fillers to thermoplastic norbornene resins, but when inorganic fillers are added, there are problems that flowability decreases to cause deterioration in moldability and furthermore, transferability of mold configuration to the surface of molded articles deteriorates and smoothness of the surface of the molded articles lowers.
DISCLOSURE OF INVENTION
The inventors have found that when a specific spherical inorganic filler is added to thermoplastic norbornene resins, there can be obtained resin compositions excellent in moldability and molded articles excellent in surface precision and dimensional stability against environmental changes such as change of temperature and humidity. Thus, the present invention has been accomplished.
That is, the present invention provides a resin composition comprising 30-95 parts by weight of a thermoplastic norbornene resin and 5-70 parts by weight of a spherical inorganic filler having an average particle diameter of 0.05-50 .mu.m and a molded article obtained therefrom.
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be explained below.
Thermoplastic Norbornene Resin
The thermoplastic norbornene resins used in the present invention are resins known in JP-A-3-14882, 3-12213.7 and 4-63807, and examples thereof are ring opening polymers of norbornene monomers and hydrogenation products thereof, addition polymers of norbornene monomers, addition polymers of norbornene monomers and olefins, and modification products of these polymers.
The norbornene monomers are also known monomers in the above patent publications and JP-A-2-227424, 2-276842, etc. Examples are norbornene and alkyl-, alkylidene or aromatic-substitution derivatives thereof, and these substituted and unsubstituted olefins which are substituted with polar groups such as halogen, hydroxyl group, ester group, alkoxy group, cyano group, amide group, imide group and silyl group, for example, 2-norbornene, 5-methyl-2-norbornene, 5,5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, 5-ethylidene-2-norbornene, 5-methoxycarbonyl-2-norbornene, 5-cyano-2-norbornene, 5-methyl-5-methoxycarbonyl-2-norbornene, 5-phenyl-2-norbornene, 5-phenyl-5-methyl-2-norbornene, etc.; monomers of polycyclic structure which are monomers of cyclopentadien
REFERENCES:
patent: 3991139 (1976-11-01), Kokuryo et al.
Database WPI, Derwent Publications Limited, London, GB; AN 94-039902.
Kohara Teiji
Koushima Yuji
Natsuume Tadao
Hoke Veronica P.
Nippon Zeon Co. Ltd.
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