| 摘要 |
<p>There is described a substantially planar, self supporting, sheet or film (optionally oriented) which comprises at least one layer comprising a first material which is very highly crystalline polymer (preferably polypropylene of 99% or greater isotacity) together with at least one second material in an amount sufficient to improve one or more of the barrier properties, mechanical properties and/or optical properties of the sheet. The second material comprises a (a) nucleating agent; (b) a polymeric material having a ring and ball softening point from about 110° C. to about 170° C. and/or (c) a hydrogenated resin such as dicyclopentadiene hydrogenated resin, a hydrogenated mixed monomer resin; and/or a resin obtainable from a mixture of a-methyl styrene, indene and/or vinyl toluene monomers. Processes for making such films and compositions for use in the process are also described. Such films are useful in shrink wrap applications for example wrapping tobacco products.</p> |
