Use of poly-indane(s) as optical data storage substrates - esp. compact discs

摘要

Use is claimed of polyindanes of formula (I) as substrates for optical data storage. R1-5 = H, 1-6C alkyl, 6-10C aryl or 5 or 6 C cycloalkyl Y = H or Ph; t = 1, 2 or 3; and n = integer of 8-250, esp. 20-120. USE/ADVANTAGE - (I) have very low double refraction and are esp. used in compact discs. In an example, polymer (I; R1 = R2 = Me; R3 = R4 = H; R5 = Me; and Y = H) (prepd. from 1,4-bis(2-chloro-2-propyl) benzene and BCl3) has Mw = 9905, Mn = 3516, Tg = 2.30% and, in the melt at 286 deg.C, D6 = 50,000 Pa, Dn = 8 x 10-6 and C is less than 1.4 x 10-10 m2/N. The constant C (polymer specific contribution to double refraction) is thus very low when compared to the value for bisphenol A homo-polycarbonate which has C less than 7.5 x 10-10 m2/N.