| 摘要 |
PURPOSE:To obtain a synthetic paper having heat sealability, tear resistance, strength, ridigity and uniform thickness by extruding a composition having specific flow index prepared by compounding an inorg. filler in high density polyethylene from a circular die to be subjected to biaxial orientation. CONSTITUTION:A composition prepared by compounding 10-80wt% inorg. filler in high density polyethylene with density of 0.940g/cm<2> or more and having flow index (n) calculated from melt viscosity curve measured at extrusion temp. shown by a formula 2<=n<=2.8 is extruded from a circular die to obtain an unoriented tubular film and the resulting unoriented tubular film is subjected to biaxial orientation at low magnification while the tubular form is held. MFR according to JIS K6760 of the high density polyethylene to be used is pref. 0.1g/10min or less and the value of the aforementioned flow index (n) is pref. 2.2 or more. When MFR is higher than 0.1g/cm or the flow index (n) is lower than 2.2, the biaxial orientation property at low magnification is lowered and a synthetic paper having uniform thickness is not obtained. |
