| 摘要 |
PROBLEM TO BE SOLVED: To continuously produce a thermoplastic polymer sheet excellent in surface smoothness, reduced in the retardation double refractive index of a plane and reduced in optical phase difference and warpage. SOLUTION: The thermoplastic polymer extruded from a T-die or coat hanger die in a molten state is allowed to flow on a roll of which the surface is subjected to mirror surface processing in an atmosphere wherein the temp. (V1) of a heating part is Tg<=V1<=Tg+100( deg.C) with respect to the glass transition point (Tg) of the thermoplastic polymer to be moved through the heating part by the rotation of the roll and the formed thermoplastic polymer sheet is brought into contact with the mirror surface of the roll under pressure by a nip roll of which the temp. (V2) is Tg-30<=V2<=Tg+100( deg.C) to be moved in the close contact state with the roll while the mirror surface is transferred to the thermoplastic polymer sheet. The temp. (V3) of the roll at a time of the peeling of the thermoplastic polymer sheet from the roll is set to V3<Tg-100( deg.C) and the temps. V1, V2, V3 are set to V3<V2<V1.
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