초록 ▼

A thermoplastic resin film at least oriented in the transverse direction with minimized bowing phenomenon is provided. The thermal shrinkage stress in the transverse direction of the film satisfies the following formula I, and the thermal shrinkage factor of said film in the transverse direction at

A thermoplastic resin film at least oriented in the transverse direction with minimized bowing phenomenon is provided. The thermal shrinkage stress in the transverse direction of the film satisfies the following formula I, and the thermal shrinkage factor of said film in the transverse direction at a temperature that is 40°C. higher than the glass transition temperature of said resin is 5% or less: (s2/s1)≤ 1.0(I) wherein s1 is the thermal shrinkage stress (kg/mm2) of the film in the transverse direction at a temperature that is 70°C. higher than the glass transition temperature of said resin, and s2 is the thermal shrinkage stress (kg/mm2) of the said film in the transverse direction at a temperature that is 80°C. lower than the melting temperature of said resin.

대표청구항 ▼

A method for producing a thermoplastic polyamide resin film at least oriented in the transverse direction, wherein the difference between the molecular orientation angles at any different two points on a straight line in the transverse direction measured by microwave techniques satisfies the followi

A method for producing a thermoplastic polyamide resin film at least oriented in the transverse direction, wherein the difference between the molecular orientation angles at any different two points on a straight line in the transverse direction measured by microwave techniques satisfies the following formula V: DQor×w/wf≤64.0 (V) wherein DQor is the difference of the molecular orientation angles (°) measured at said two points, wf is the distance (m) of said points, and w is the width (m) of said film, which comprises the steps of drawing a thermoplastic polyamide resin film in the transverse direction in a drawing zone, said film containing at least 1.0% by weight of water based on the total weight of said film and water, cooling said film to a temperature lower than the glass transition temperature of said polyamide resin in a cooling zone, heat-setting said film in a heat-setting zone, and allowing said film to shrink by a positive amount in the longitudinal direction, wherein the length of said cooling zone satisfies the following formula VI: (L/W)≥1.0 (VI) wherein L is the length (m) of said cooling zone, and W is the width (m) of said film after the drawing is carried out.