| 摘要 |
PROBLEM TO BE SOLVED: To use a spacer held at an accurate gap with excellent thickness accuracy and small sheet warp by cooling a thermoplastic polymer sheet melt extruded from a T-die or a coating hanger die by a metal belt having a length so that a contact time at a non-curvature part becomes specific in a flowing direction. SOLUTION: An air gap distance until a thermoplastic polymer sheet is brought into contact with a metal belt after the sheet is extruded from a T-die or a coating hanger die having a lip gap of predetermined times as large as a thickness of the sheet is set to a predetermined length. When the gap exceeds a predetermined value, a thickness accuracy is deteriorated, and hence to fall the gap within a predetermined value, a diameter of a roll is reduced, and a lip end of the die is formed in a shape along the roll. A length of the belt is set so as to sufficiently cool the sheet by bringing a cooling time at a position having no curvature to the flowing direction of the sheet into 20 s or above. Thus, a spacer for holding the accurate gap becomes optimum with excellent thickness accuracy and small sheet warp.
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