Cycloolefin copolymer formed by ring-opening polymerization, process for producing the same, and optical material

Abstract

Disclosed herein are a ring-opened cycloolefin copolymer excellent in optical properties such as transparency, low in water (moisture) absorption property, high in affinity for other materials, good in post processing properties such as adhesive property and printability, and excellent in heat resistance and mechanical strength, a production process thereof, and an optical material. The ring-opened cycloolefin copolymer of the invention contains a structural unit (A) represented by any one of general formulae (1-1) to (1-3) and a structural unit (B) derived from a specific cycloolefin having an ester group in a proportion of 10:90 to 50:50 in terms of a molar ratio, wherein a monomer for obtaining the structural unit (A) is a tricyclomonoolefin compound containing an endo form in a proportion of at least 80 mol % and has a glass transition temperature of 120 to 250° C.: wherein in the general formulae (1-1) to (1-3), R1 to R13 individually represent a group selected from a hydrogen atom, halogen atoms, and alkyl groups and halogenated alkyl groups having 1 to 4 carbon atoms, and X1 to X3 mean individually an ethylene group or vinylene group.

Description

TECHNICAL FIELD [0001] The present invention relates to a ring-opened cycloolefin copolymer and a production process thereof, and an optical material, and particularly relates to a ring-opened cycloolefin copolymer excellent in optical properties such as transparency, high in affinity for other materials, good in post processing properties such as adhesive property and printability, excellent in balance between affinity for other materials and low water (moisture) absorption property and also excellent in heat resistance and mechanical strength and a production process thereof, and an optical material. BACKGROUND ART [0002] With the demand for weight saving, miniaturization and high-density packaging of electronic apparatus in recent years, replacement of inorganic glass with optically transparent resins is proceeded in fields of optical parts and liquid crystal display parts such as lenses, backlights, light guide plates and liquid crystal substrates, in which the inorganic glass h...

AI Technical Summary

Benefits of technology

[0034] The present invention has been made on the basis of the foregoing circumstances and has as its first object the provision of a ring-opened cycloolefin copolymer excellent in optical properties such as transparency, high in affinity for other materials, good in post processing properties such as adhesive property and printability, excellent in balance between affinity for other materials and low water (moisture) absorption property and also excellent in heat resistance and mechanical strength.

[0035] A second object of the present invention is to provide a process capable of advantageously producing the ring-opened cycloolefin copolymer.

Problems solved by technology

However, these cycloolefin addition polymers exhibit a glass transition temperature exceeding 300° C., and so they have very high heat resistance, but involve such problems that thermal molding and forming such as injection molding and extrusion molding become difficult on the other hand.

Since these catalyst systems scarcely exhibit polymerizing ability to monomers containing polar groups such as an ester group and alkoxysilyl groups, however, it is difficult to impart functions such as adhesive property to the resulting copolymer or introduce crosslinking groups such as a hydrolyzable silyl group.

In addition, the cycloolefin addition copolymers may become low in transparency due to crystallinity of an ethylene chain, or the like in some cases and are not always suitable for use as optical materials.

However, such ring-opened cycloolefin (co)polymers or hydrogenated products thereof are low in affinity for other materials because they have no polar group, and involve a problem in properties as to post processing such as adhesion, printing and vapor deposition.

However, such ring-opened cycloolefin (co)polymers or hydrogenated products thereof are low in mechanical strength, so that a problem may arise in some cases when thin molded products such as sheets or films are formed.

Therefore, when DCP is used as a raw material for industrially producing a cycloolefin polymer, there is a problem that it may interfere with the production of the cycloolefin polymer.

However, such a ring-opened (co)polymer is that obtained through ring-opening the 5-membered ring in tricyclo[5.2.1.02.6]dec-3-ene, and its hydrogenated product contains a chain of 3 methylene groups in the structural unit, so that a problem that only a polymer relatively low in glass transition temperature can be obtained arises.

However, the glass transition temperatures of these ring-opened (co)polymers are all lower than 120° C., and so they do not have any performance satisfied as materials of which heat resistance is required.

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