| 摘要 |
PURPOSE:To obtain a substrate with very little double refraction, excellent light permeability, little warpage due to water absorption, excellent mechanical strength and heat resistance by forming the substrate from specific polyester, polyester carbonate or polycarbonate resin. CONSTITUTION:The substrate consists of polyester, polycarbonate or polyester carbonate having recurrent units expressed by formula I. In the formula, R1 and R2 represent a bond or alkylene group, alkylidene group, etc., having <=8 carbons. There may be a bond or cross-linkage comprising alkylene group or alkylidene group with <=6 carbons between R1 and R2. It is inhibited that both of R1 and R2 are bonds. R3 and R4 represent hydrogen atom or alkyl group with <=4 carbons. x and y represent the proportion of copolymerization, x:y=100:0 to 0:100 (in molar ratio). (n) is 0, 1 or 2. By this method, the obtd. substrate has very little double refraction, excellent light permeability, little warpage due to water absorption, and excellent heat resistance and mechanical strength. |
