| 摘要 |
PURPOSE:To obtain a film excellent in lubricity and transparency, by applying an aqueous dispersion of a special polyester resin at least onto one surface of a polyester film that has been melt-extruded and unstretched or uniaxially stretched, and stretching it uniaxially or biaxially. CONSTITUTION:An aqueous dispersion of a polyester resin comprising a water- insoluble polyester copolymer (A) containing a sulfonic acid metal base-containing dicarboxylic acid in an amount of 0.5-15mol% based on all the mixed dicarboxylic acid constituents, a water-soluble organic compound (B) having a boiling point of 60-200 deg.C, water (C), inorganic particles (D) and a polyfunctional reactive compound (E) in a weight ratio given in equation 1 is applied to at least one surface of a melt-extruded polyester film that has been unstretched or uniaxially stretched. Then the film is stretched uniaxially or biaxially. If (A)/(B) is higher than 5, the dispersibility lowers. If (A)/(B) is lower than 0.02, or (A)/ (B) is higher than 2, there will be a risk of explosion due to the solvent. If (B)/(C) is lower than 0.01, the surface tension becomes large and speckles appear. A ratio of (A)/(D)=100,000/0.5-300 is favorable, and if the ratio of (A)/(E) is outside of 1-40, the lubricity is unsatisfactory. |
