| 摘要 |
PROBLEM TO BE SOLVED: To provide the subject film having improved light-shield, whiteness, and covering property by having a crosslinked resin dispersed into a white polyester film contg. a polyester resin and white inorganic microparticles. SOLUTION: One hundred pts.wt. of at least one kind of a resin selected from a polyester resin, an acrylic resin, and a urethane resin was added with such additives as a reaction initiator, a reaction accelerator, etc., and with 0.01-50 pts.wt. of a cross-linking agent, then made a crosslinking reaction to give a cross-linked resin in which a temp. at the 0 wt.-loss time in the heating- loss curve is 300 deg.C or above. Blending a polyester resin with 0.5-35 wt.%, pref. 10-25 wt.% of white inorganic microparticles having an average particle dia. of 0.05-5μm, pref. 0.1-3μm; 0.01-20 wt.%, pref. 0.1-15 wt.% or the crosslinked resin; and if necessary 0.005-1 wt.%, pref. 0.05-0.5 wt.% of a fluorescent whitening agent, and molding into a film form, give a white polyester film having a thickness of 10-500μm, an optical density of 0.5-2, whiteness degree of 70-120%, and a color tone of b value (color-difference meter) or 2--5.
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