CYCLOOLEFIN COPOLYMERS HAVING HIGH TEAR STRENGTH AND LOW OPTICAL ATTENUATION

Cycloolefin copolymers having high tear strength and low optical attenuation A process for the preparation of a copolymer of cycloolefin copolymer (COC) having high tear strength by copolymerization of 0.1 to 99.9% by weight, based on the total amount of the monomers, of at least one monomer in which R1, R2, R3, R4, R5, R6, R7 and R8 are identical or different and are a hydrogen atom or a C1-C8-alkyl radical or a C6-C16-aryl radical, where identical radicals in the various formulae can have different meanings, from 0 to 99.9% by weight, based on the total amount of the monomers, of a cycloolefin in which n is a number from 2 to 10, and from 0.1 to 99.9% by weight, based on the total amount of the monomers, of at least one acyclic 1-olefin in which R9, R10, R11 and R12 are identical or different and are a hydrogen atom or a C1-C8-alkyl radical or a C6-C16-aryl radical, in solution, in suspension, in a liquid cycloolefin monomer or cycloolef in monomer mixture or in the gas phase, at a temperature of from -78 to 150.degree.C, at a pressure of from 0,5 to 64 bar, in the presence of a catalyst comprising a metallocene as transition-metal component and an aluminoxane for the linear type and/or for the cyclic type, where, in the formulae VII and VIII, R13 is a C1-C6- alkyl group or phenyl or benzyl, and n is an integer from 2 to 50, where the polymerization is carried out in the presence of a catalyst whose transition-metal component is at least one compound of the formula IX in which M1 is titanium, zirconium, hafnium, vanadium, niobium or tantalum, R14 and R15 are identical or different and are a hydrogen atom, a halogen atom, a C1-C10-alkyl group, a C1-C10-alkoxy group, a C6-C10-aryl group, a C6-C10-aryloxy group, a C2-C10-alkenyl group, a C7-C40-arylalkyl group, a C7-C40-alkylaryl group or a C8-C40-arylalkenyl group, and -32- m may be one or two, depending on the valency of the central atom M R18 is =BR19, =AIR19, -Ge-, -Sn-, -O-, -S-, =SO, =SO2, =NR19, =CO, = PR19 or =P (O) R19, where R19, R20 and R21 are identical or different and are a hydrogen atom, a halogen atom, a C1-C10-alkyl group, a C1-C10-fluoroalkyl group, a C6-C10-fluoro-aryl group, a C6-C10-aryl group, a C1-C10-alkoxy group, a C2-C10-alkenyl group, a C7-C40-arylalkyl group, a C8-C40-arylalkenyl group or a C7-C40-alkylaryl group, or R19 and R20 or R19 and R21, in each case with the atoms connecting them, form a ring, M2 is silicon, germanium or tin, R16 and R17 are identical or different and are