Organo polysiloxane, hard coating composition, and resin substrate having hard coating layer

摘要

An organo polysiloxane to improve the abrasion and weather resistance of a hard coating layer obtained from a silicone-type hard coating composition. The hard coating composition contains a first organo polysiloxane having silicone-containing bond units selected from the group consisting of R—Si(—OX)2(—O*—), R—Si(—OX)(—O*—)2 and R—Si(—O*—)3) and a second organo polysiloxane having the same, where the second organo polysiloxane has a weight average molecular weight of 1/10 to 1/1.5 times that of the first organo polysiloxane. Further, a resin substrate having a hard coating layer made of a cured product of the hard coating composition that has improved abrasion and weather resistance. For resin substrates used in a bent state, the hard coating layer also improves the cracking resistance associated with mechanical stress.

主权项

1. A hard coating composition comprising an organo polysiloxane component consisting of an organo polysiloxane (a) having silicon-containing bond units represented by the following formulae T1 to T3 and an organo polysiloxane (b) having silicon-containing bond units represented by formulae T1 to T3, wherein the organo polysiloxane (a) contains silicon-containing bond units represented by formulae T1 to T3 in a ratio of T1:T2:T3=0-5:15-40:55-85 and in a ratio of T3/T2=1.5-4.0, in a number of such units, wherein a ratio of the number (B) of hydroxy groups bonded to silicon atoms to the number (A) of alkoxy groups bonded to silicon atoms in the organo polysiloxane (a), (B)/(A), is from 12 to 58.7, and which has a weight average molecular weight of from 800 to 8,000, and wherein the organo polysiloxane (b) is an organo polysiloxane having a weight average molecular weight between 1/10 and 1/1.5 of the weight average molecular weight of the organo polysiloxane (a):
R—Si(—OX)2(—O*—)  T1: R—Si(—OX)(—O*—)2  T2: R—Si(—O*—)3  T3: wherein R is a hydrogen atom or a C1-10 substituted or unsubstituted monovalent organic group, X is a hydrogen atom or a C1-6 alkyl group, and O* is an oxygen atom linking two silicon atoms, and the ratio of the content of the organo polysiloxane (b) to the organo polysiloxane (a) is from 1.5 to 30 by mass ratio; wherein a proportion of the number of T units in said organo polysiloxane (a) is 95 to 100% based on the total number of units T, M, D and Q, wherein M is of formula R3—Si(—O*—), Q is of formula Si(—O*—)4 and D is of formula R2—Si(—O*—)2; and wherein the total number of units D in the organo polysiloxane (b) is 0.