| 摘要 |
PURPOSE:To improve the flatness, slipperiness and abrasion resistance of a film surface, by incorporating a number of surface projections of a specified height based on crosslinked polymer particles in a polyester film. CONSTITUTION:Crosslinked polymer particles are obtd. by copolymerizing a compound contg. an aliph. unsatd. bond in its molecule (e.g., methyl methacrylate) and a compound contg. two or more aliph. unsatd. bonds in its molecule (e.g., divinylbenzene) as a crosslinking agent in the presence of a polymn. initiator, grinding the obtd. polymer and removing particles of large sizes. The obtd. particles are compounded in a desired stage of preparation of a polyester (A) which is a polymer contg. polyethylene terephthalate as a main component and, if necessary, diluted with another polyester and the mixture is made into a film to obtain the title film having an average roughness on the center line of the film of 0.03mum or less and a height of projection in the range of 0.05-0.3mum wherein a relation between the height of projection [X(mum)] and the number of projections [Y/mm<2>] satisfies the formula and the number of the projections having a height of 0.4mum or larger are 20/mm<2> or less. |
