| 摘要 |
PURPOSE:To manufacture a polyamide film with a high flatness capable of sufficiently coping with even the improvement of production speed by the use of a specific method of humidity control. CONSTITUTION:The manufacture of biaxially stretched film is such to that after being subjected to biaxial stretching, the polyamide film is so heat-fixed that the contraction coefficient in a hot water of 100 deg.C is allowed to be 3% or less in both the longitudinal and transverse directions and, after that, while continuously blowing humidified air of temperature of 150 deg.C or lower, the moisture content of the film is controlled within the range of 0.5-2.0%, and the film is wound subsequently, wherein the film is cooled below the dew point of humidified air. Thus, a biaxially stretched polyamide film is obtained which has an excellent flatness, and is not liable to crease when rolled, and also has reduced in the occurrence of curl, slack, wrinkle and the like due to moisture absorption which has been a problem in the after working process, in the past. |
