Abstract
Various characteristics of biaxially oriented polyester film that is laminated on to steel for can use are controlled by the degree of biaxial orientation and the thickness of amorphous layer of the laminated film. The adhesive property and the corrosion resistance of the steel deteriorate with increasing laminating speed because of decreasing thickness of amorphous layer even at the same degree of orientation. We found that it is effective to maintain the enough contact cooling time of laminated film in order to prevent the amorphous thickness reduction. Because high speed laminating is indispensable for the better productivity, it is important to find the method of keeping the contact cooling time constant.
Therefore, this report deals with the result of numerical analysis applied to characterize heat transfer in new laminating process, which was considered and accepted to maintain the contact cooling time by winding the steel along the laminating roll for prevention of decreasing thickness of amorphous layer with increasing laminating speed. Based on the result of numerical analysis, we obtained the transient crosssectional temperature distribution of polyester film in the laminating process compared with the ordinary laminating process.
The thickness of amorphous layer with the numerical analysis obtained by the cross-sectional variation of maximum temperature of film in the roll nip agrees well with the one observed by polarizing microscope. The estimation of the thickness of amorphous layer was found possible by this method with a good accuracy.
The variations of biaxial orientation of the laminated film on non-contact side after leaving roll nip in this laminating process is also discussed.
