| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively obtain a stretched film high in thickness accuracy and having high function and high value added. SOLUTION: Hot air heated to predetermined temp. by a radiator 1 is injected to the upper and rear surfaces of a stretched film 7 and the injected hot air is returned to the rediator 1 by upper and lower return passages to be again heated to the predetermined temp. to be injected to the stretched film 7. When stretching is performed while this operation is repeated, in the respective upper and lower return passages, the hot air injected at a place relatively near to the radiator 1 and the hot air injected at a relatively remote place are mixed by first and second buffle plates 30, 30..., 40, 40.... The mixed hot air in the upper hot air return passage is guided to the lower part 1b of the radiator 1 by mixing ducts 10, 10 and the hot air mixed in the same way in the lower hot air return passage is guided to the upper part 1u of the radiator 1. |
