Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1990-06-07
1996-12-03
Schofer, Joseph L.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525338, 526281, C08F23208, C08F 804
Patent
active
055809340
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a novel ring-opening hydrogenated copolymer excellent in thermal resistance, optical property and moldability. In more particular, it relates to a polycyclic norbornene or its derivative ring-opening hydrogenated copolymer which is excellent in thermal resistance and gives moldings with little optical strain, and a process for producing the same.
BACKGROUND ART
Polymers hitherto mainly used as optical materials are polymethyl methacrylate and polycarbonate. However, the former has a problem of rather high water absorption and the latter has a problem of development of birefringence in injection molding. Accordingly, it is becoming difficult for these polymers to meet recent requirements, which are becoming increasingly more severe.
in recent years, polymers which use polycyclic norbornene or allied monomers have been developed as polymeric materials improved in said properties in question. For example, Japanese Patent Application Kokai (Laid-open) No. 60-26024 describes that the hydrogenation products of ring-opening polymers of tetracyclodecenes or of ring-opening copolymers of tetracyclododecenes and norbornenes are excellent in transparency, water resistance and thermal resistance. However, the hydrogenation products of ring-opening polymers of tetracyclododecenes are not fully satisfactory in moldability and their birefringence values are not so small as can meet the property requirement sufficiently. The hydrogenation products of ring-opening copolymers of tetracyclododecenes and norbornenes also have similar problems. Although hydrogenation products of this kind having a high proportion of norbornenes in copolymerization of 40-50% by mole are somewhat improved in said properties, they have a low glass transition temperature (Tg) of 95.degree.-105.degree. C. and hence their thermal resistance is not fully satisfactory.
Japanese Patent Application Kokoku (Post-Exam. Publn.) No. 58-43412 describes that the hydrogenation product of dicyclopentadiene ring-opening polymer can be easily heat-melt processed to give a tough, transparent sheet. The hydrogenation product, however, is unsatisfactory in thermal resistance for use as optical disks because it has a low glass transition temperature (Tg) of about 95.degree. C.
On the other hand, polymers obtained by using polycyclic norbornene or allied monomers, when they have not been hydrogenated, are poor in resistance to oxidative degradation and hence unsuitable for use as optical materials.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a novel polymeric material which is excellent in thermal resistance, optical property and moldability.
Another object of the present invention is to provide a polycyclic norbornene or its derivative ring-opening hydrogenated copolymer which has a high glass transition temperature and gives moldings with little optical strain.
The present inventors have made extensive study to develop a novel synthetic resin suitable as optical polymer or as the raw material thereof by using polycyclic norbornene or allied monomers. As the result it has been found out that the hydrogenation products of ring-opening copolymers obtainable by ring-opening copolymerization of (A) pentacyclopentadecadienes and/or pentacyclopentadecenes, (B) tetracyclododecenes and, as desired, (C) as least one monomer selected from dicyclopentadienes, dihydrodicyclopentadienes and norbornenes are excellent in thermal property and moldability and give moldings with little of optical strain. The present invention has been accomplished on the basis of above finding.
BEST MODE FOR CARRYING OUT THE INVENTION
The first aspect of the present invention relates to a polycyclic norbornene or its derivative ring-opening hydrogenated copolymer which contains [I] or the alkyl-substituted derivative thereof, and [II] or the alkyl-substituted derivative thereof, has an intrinsic viscosity [.eta.] of 0.01-20 dl/g as determined in toluene at 25.degree. C., and in which at least 50% of the (C-----
REFERENCES:
WPIL, File supplier, accession No. 89-210066, Derwent Publications, Ltd. London, GB: & JP-A-1 146 923.
Kohara Teiji
Natsuume Tadao
Nishi Yoshikatsu
Oshima Masayoshi
Cheng Wu C.
Nippon Zeon Co. Ltd.
Schofer Joseph L.
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