Sheet or film composed of cyclo-olefin polymer

A sheet of a film composed of an intimate mixture of:

• (A) at least one cyclo-olefin polymer selected from the group consisting of ring-opened polymers of at least one cyclo-olefin of formula (I) ##STR110## wherein R.sup.1 to .sup.12, independently from each other, represent a member selected from the class consisting of a hydrogen atom, halogen atoms and hydrocarbon groups;
• two of R.sup.9 to R.sup.12 may be linked to each other together with the carbon atoms to which they are bonded to form a monocyclic or polycyclic group which may contain a double bond;
• R.sup.9 and R.sup.10, or R.sup.11 and R.sup.12 may each form an alkylidene group together with the carbon atoms to which they are bonded;
• and n is 0 or a positive integer, hydrogenation products of said polymers;
• and addition polymers of the cyclo-olefins of formula (I) with ethylene, said cyclo-olefin polymer having an intrinsic viscosity [.eta.], measured in decalin at 135.degree. C., of 0.01 to 10 dl/g and a softening temperature of at least 70.degree. C.
• (B) at least one flexible polymer in which a crosslinked structure is formed, said flexible polymer being selected from (1) flexible copolymer of ethylene, another alpha-olefin, and the cyclo-olefin of formula (I) which has an intrinsic viscosity, measured in decalin at 135.degree. C., of 0.01 to 10 dl/g, and a glass transition temperature of not more than 20.degree. C., (2) amorphous or low-crystalline alpha-olefin copolymers formed from at least two alpha-olefins and having a glass transition temperature of not more than 0.degree. C., (3) alpha-olefin/diene copolymers formed from at least two alpha-olefins and at least one conjugated diene and having a glass transition temperature of not more than 0.degree. C., (4) aromatic vinyl hydrocarbon/conjugated diene random or block copolymers having a glass transition temperature of not more than 0.degree. C. and (5) flexible polymers formed from isobutylene and flexible copolymers formed from isobutylene and conjugated dienes.