| 摘要 |
PROBLEM TO BE SOLVED: To provide an improving method for manufacturing a polyester multilayer film with its central layer composed of straight-chain low density polyethylene(LLDPE) by the cast extrusion molding. SOLUTION: LLDPE polyethylene of density of 0.915-0.935g/cm<3> having at least bonding properties is extrusion molded by a series of extruders, and layers are formed by the function of the extruders by which the material is extruded, and the material forming the layers is pressed through a lip of an enlarging head and discharged to the peripheral environment. The material discharged out of the enlarging head is collected to a first cooling roll cooled by water kept at 10-25 deg.C, and then the film coming out of the first cooling roll is cooled by water kept at 10-20 deg.C, which is lower than the temperature of the first roll, and transferred to a second cooling roll, the peripheral speed or the rotation speed of which is faster than that of the first roll by 10-40%. |
