| 摘要 |
PURPOSE:To obtain a transparent plastic board which has the reduced internal distortion and the excellent stability of measurement, by using a raw material of the aromatic polyester that has a >=75 deg.C glass transition temperature and is substantially linear. CONSTITUTION:The aromatic polyester which has a >=75 deg.C glass shift temperature and is substantially linear is obtained by polycondensing with a normal process (A) an acid component containing bifunctional carboxylic acid (derivative) containing >=50% terephthalic acid and other component which is preferably isophthalic acid and (B) an alcohol component containing dihydroxy compound (derivative) such as 1,4-cyclohexane dimethanol, bis(4-hydroxyethoxyphenol)sulfone. Then this polyester receives the extrusion molding for example to obtain a nonexpanded sheet of 1-2mm. thickness, and the pit of a stamper (original board) is transcribed. The sheet is then cut into a disk shape of a prescribed size to produce the titled board. |
