Method of cutting polymer film
A film, whose a glass transition temperature of a polymer is Tg, is heated so as to satisfy a formula, (Tg−90)≦T≦(Tg−30). The heating is made by feeding a warm air from a duct to the film. Temperature and flow rate of the air from the duct are controlled. The trimming is made by a shearing slitter. Further, if a distance from a heating position by the warm air to a slitting position of the shearing slitter is from 10 mm to 200 mm, no trimming dusts and the powdery materials are not adhered to a product part of the obtained film, and the slitting of the film forms adequate edges of the product part.
1 . A method of cutting with a cutter a film formed from a polymer, comprising:
controlling a temperature T (unit; ° C.) of said film at the cutting such that said temperature T may be satisfy a following formula,
Tg−90≦T≦Tg−30
wherein Tg (unit; ° C.) is a glass transition temperature of said polymer.
2 . A method according to claim 1 , wherein said film is continuously transported.
3 . A method according to claim 2 , wherein the control of said temperature T is made with use of a heating device, and a distance between a heating position by the heating device and a cutting position of the cutting is at least 10 mm and at most 200 mm.
4 . A method according to claim 3 , wherein both surfaces of said film are heated by said heating device.
5 . A method according to claim 4 , wherein said heating device is an air feeding device and an illuminating device.
6 . A method according to claim 5 , wherein said illuminating device is an incandescent lamp or an infrared ray heater.
7 . A method according to claim 2 , wherein said cutter is a rotary type shearing slitter or a rotary type razor cutter.