A random copolymer comprising ethylene, a 1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene and optionally an alpha-olefin having at least three carbon atoms or cycloolefin. The mole ratio of polymerized units from the 1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene to polymerized units from ethylene is from 3:97 to 95:5 and the 1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene is incorporated in the polymer chain as polymerized units without ring-opening. The copolymer is prepared by copolymerizing ethylene with the 1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene in a hydrocarbon medium in the presence of a catalyst formed from a vanadium compound and an organoaluminum compound which are soluble in the hydrocarbon medium. The copolymer has excellent transparency and a well balanced combination of heat resistance, heat aging resistance, chemical and solvent resistance, dielectric properties and mechanical properties such as rigidity.
In an optical disc structure for information recording comprising two discs in the form of an annular coaxial plate having optical recording thin layers of one surface thereof, the discs being melt-adhered by ultrasonication via annular coaxial sealing members composed of an outer annular spacer and an inner annular spacer to form an air sandwich structure so that the optical recording thin layers face each other through an air space, provided that one of the optical recording thin layers may be omitted. The sealing members and said discs are formed of a copolymer of ethylene. The ethylene copolymer forming the sealing members has an ethylene content (a) of 55 to 80 mole % and the ethylene copolymer forming the discs has an ethylene content (b) of 50 to 70 mole %, where (a) is larger than (b).
(1) A solvent-soluble ring-opened polymer constituted of 100-50% by weight of a norbornene derivative of monomer (A) represented by the formula ##STR1## wherein, R.sub.1 and R.sub.2 are the same or different and each denote hydrogen or alkyl and m denotes an interger of 0 to 2, and 0-50% by weight of another norbornene derivative of monomer (B) capable of undergoing ring-opening copolymerization with the preceding monomer (A), the polymer having a number average molecular weight of 10,000 to 50,000, a weight average molecular weight-to-number average molecular weight ratio (Mw/Mn) of up to 3, and a glass transition temperature of at least 80.degree. C., and (2) a process for producing such ring-opened polymers as stated above.
In accordance with the present invention, there are provided cycloolefin type random copolymer compositions excellent in heat resistance, chemical resistance, rigidity, impact resistance, etc., which comprise (A) a cycloolefin type random copolymer containing an ethylene component and a cycloolefin component and having an intrinsic viscosity [.eta.] of 0.05-10 dl/g as measured at 135.degree. C. in decalin and a softening temperature (TMA) of not lower than 70.degree. C., and (B) one or more non-rigid copolymers selected from the group consisting of: (i) a cycloolefin type random copolymer containing an ethylene component, at least one other .alpha.-olefin component and a cycloolefin component and having an intrinsic viscosity [.eta.] of 0.01-10 dl/g as measured at 135.degree. C. in decalin and a softening temperature (TMA) of below 70.degree. C., (ii) a non-crystalline to low crystalline .alpha.-olefin type elastomeric copolymer formed from at least two .alpha.-olefins, (iii) an .alpha.-olefin-diene type elastomeric copolymer formed from at least two .alpha.-olefins and at least one non-conjugated diene, and (iv) an aromatic vinyl type hydrocarbon-conjugated diene copolymer or a hydrogenated product thereof, and optionally (c) an inorganic filler or organic filler.
Compositions comprising (A) cycloolefin random copolymer containing an ethylene component, and a cycloolefin component represented by the general formula [I] or [II] and having an intrinsic viscosity of 0.05-10 dl/g as measured at 135.degree. C. in decalin and a softening temperature (TMA) not lower than 70.degree. C., and (B) a cycloolefin random copolymer containing an ethylene component, and a cycloolefin component represented by the general formula [I] or [II] and having an intrinsic viscosity of 0.01-5 dl/g as measured at 135.degree. C. in decalin and a softening temperature (TMA) of below 70.degree. C., the weight ratio of said (A) component/(B) component ranging from 100/0.1 to 100/10. The composition is particularly useful for molding an information recording base board.
The laminate of the invention comprises a substrate and a resin surface layer having a glossiness of not less than 60% when measured at an incidence angle of 60.degree. laminated on at least one side surface of the substrate, and the substrate is formed from at least one cycloolefin polymer (A) selected from the group consisting of a random copolymer (a-1) of specific cycloolefin and ethylene, a ring opening polymer (a-2) of specific cycloolefin, a ring opening copolymer (a-3) of specific cycloolefin and a hydrogenation product (a-4) of the ring opening polymer or the ring opening copolymer, or formed from a cycloolefin resin composition (B) comprising the cycloolefin polymer (A) and crystalline polyolefin and/or an .alpha.-olefin elastomeric copolymer. The substrate shows excellent resistance to flon gas, so that the resin surface layer is effectively prevented from occurrence of cracks caused by influence of flon gas.
