| 摘要 |
Oriented syndiotactic polystyrene-type film (I) has 3D surface roughness S delta a of 0.004-0.04 on at least one side and air permeability rate of 900 s or less. Pref. the air permeability rate is 700 s or less. (I) contains inert lubricant particles (II), consisting of metal oxides or salts or organic polymers, pre.f SiO2, TiO2, talc, kaolinite, CaCO3, Ca phosphate, BaSO4 or silicone resin. (II) pref. have an average particle dia. of 0.01-2.0 microns and scatter of 25% or less and pref. include at least one type of particles with an areal shape factor of 60% or more. The amt. is 0.005-2.0 (wt.% (II) w.r.t. (I). (I) consists of polymer with Mw = 1000-1500000. It is drawn in at least one direction to give a refractive index of 1.600-1.623, pref. 1.600-1.620 in the thickness direction and thermal shrinkage of max. 3, pref. max. 2% at 150 deg. C. (I) is drawn at least once at a rate of at least 10000%/min. at 115-140 deg. C, then subjected to heat treatment at 170-270 deg. C and to relaxation treatment with a ratio of 2% or more in the machine and/or transverse direction, during or after heat treatment. USE/ADVANTAGE - (I) is used as capacitor dielectric film, wrapping film, film for use in photochemical processes, laminates with metal or metal oxide or film base for adhesive tape or printed circuits (claimed). It is useful e.g. making copies for overhead projectors, gravure printing, stacks of film for copiers or printing machines. The handling properties (slip, blocking coefft.) of this film are not impaired, even if high operating speeds are used. |
