PRODUCTION METHOD FOR THERMOPLASTIC POLYMER SHEET AND OPTICAL SHEET

摘要

The present invention provides a process for continuously producing a thermoplastic polymer sheet superior in surface smoothness, small in plane retardation, i.e. small in optical phase difference, and small in warpage. The present invention lies in a process for producing a thermoplastic polymer sheet, which comprises converting a thermoplastic polymer sheet formed by melt extrusion from a T die or a coat hanger die, to a cooled sheet by using a metal belt having a maximum surface roughness (Rmax) of 0.1 mu m or less and also such a length that the time of contact of the extruded thermoplastic polymer sheet with the metal belt portion free from any curvature in the flow direction of the extruded thermoplastic polymer sheet becomes 20 seconds or more.