Patent ID: 8821783

Claim:
A decurling method for a continuous multi-layer film including a first layer having a first film surface, and a second layer, overlaid on said first layer opposite to said first film surface, having an external second film surface, wherein there is a curling tendency in an outward direction with said second film surface, said decurling method comprising steps of: transporting said multi-layer film by a plurality of transport rollers arranged in a longitudinal direction of said multi-layer film for supporting said external second film surface, with said multi-layer film being transported in an upward direction; preheating said multi-layer film within a range of setting said second layer at a temperature equal to or lower than a glass transition temperature of a component therein; inducing a first transition of said second layer during transport into a rubber phase by supplying fluid vapor on said second film surface, the fluid vapor being discharged in a fluid vapor flow area positioned between two adjacent transport rollers among said transport rollers along said multi-layer film, a distance between said fluid vapor flow area and said transport rollers being equal to or more than 100 mm; maintaining a fluid vapor content of a contacting portion of said multi-layer film contacting said transport rollers in a range lower than a fluid vapor content of said second film surface supplied with said fluid vapor, said fluid vapor directed toward said contacting portion being aspirated or blocked, dry gas being supplied to said contacting portion; inducing a second transition of said second layer from said rubber phase into a glass phase by stopping supplying said fluid vapor; wherein during said first and second transition, said multi-layer film is transported while said multi-layer film is prevented from contacting a solid object.