| abstract |
PURPOSE: The titled material having a small photoelastic constant and a high sensitivity of reading information recorded on a disk, obtained by reacting a specified compound with a halogenated methane. n CONSTITUTION: 4,4'-Dihydroxytetraphenylmethane of formula I , 1-phenyl-1,1-bis(4- hydroxyphenyl)ethane of formula II, or a compound of formula III (wherein m is 4W10) is reacted with a halogenated methane (e.g., CH 2 Cl 2 ) in the presence of a catalyst and an MW modifier to obtain a material for optical instruments and devices comprising a polyformal polymer having repeating units of formula IV(wherein R 1 is a group of one of formulas VWVII) and a reduced viscosity [ηsp/ c] as measured in a methylene chloride solution at a concentration of 0.5g/dl at 20°C, ≥0.2dl/g. n USE: Audiodisk and optical memory disk. n COPYRIGHT: (C)1985,JPO&Japio |