Curable composition and method of forming cured product

Patent metadata

Field	Value
Publication number	US-12534619-B2
Application number	US-202319100020-A
Country	US
Kind code	B2
Filing date	Jul 26, 2023
Priority date	Jul 31, 2022
Publication date	Jan 27, 2026
Grant date	Jan 27, 2026

Abstract

A curable composition comprises: (A) an organopolysiloxane having an average of at least two silicon-bonded aliphatically unsaturated groups per molecule; (B) an organopolysiloxane free from aliphatically unsaturated groups and having an average of at least two mercapto groups per molecule; (C) a photoinitiator; (D) an acryloxy-functional silane; and (E) a tetraorthosilicate.

First claim

What is claimed is:

1 . A curable composition, comprising:
(A) an organopolysiloxane having an average of at least two silicon-bonded aliphatically unsaturated groups per molecule; wherein the (A) organopolysiloxane comprises:
(A1) a first linear organopolysiloxane having a degree of polymerization of from 550 to 2000; and
(A2) a second organopolysiloxane having a degree of polymerization of from 50 to 500;
(B) an organopolysiloxane free from aliphatically unsaturated groups and having an average of at least two mercapto groups per molecule; (C) a photoinitiator; (D) an acryloxy-functional silane represented by the following formula:

wherein X is a divalent hydrocarbon group, each R is independently a hydrocarbyl group, each R 1 is independently an alkyl group having from 1 to 8 carbon atoms, subscript x is 2 or 3, and R 2 is H or R 1 ; and

(E) a tetraorthosilicate of the formula: Si(OR 3 ) 4 , wherein each R 3 is independently an alkyl group having from 1 to 10 carbon atoms.

2 . The composition of claim 1 , wherein the composition further comprises: (F) a filler; or (G) a condensation catalyst; or both.

3 . The composition of claim 1 , wherein:
the (A) organopolysiloxane is present in an amount of from 5 to 95 wt. %; the (C) photoinitiator is present in an amount of from 0.01 to 10 wt. %; the (D) acryloxy-functional silane is present in an amount of from 0.05 to 5 wt. %; and the (E) tetraorthosilicate is present in an amount of from 0.05 to 5 wt. %; each based on the total weight of the composition.

4 . The composition of claim 1 , wherein the total molar ratio of mercapto groups of component (B) to silicon-bonded aliphatically unsaturated groups in components (A) and (D) is from 0.1:1 to 3:1.

5 . The composition of claim 1 , wherein the (A) organopolysiloxane is represented by the following average formula:
(R 4 3-m R 5 m SiO 1/2 ) a (R 4 2-n R 5 n SiO 2/2 ) b (R 5 SiO 3/2 ) c (SiO 4/2 ) d (ZO 1/2 ) e wherein each R 4 is an independently selected substituted or unsubstituted hydrocarbyl group free from aliphatic unsaturation; each R 5 is independently R 4 or an aliphatically unsaturated group having from 1 to 10 carbon atoms; each subscript m is independently an integer from 0 to 3 in each unit indicated by subscript a; each subscript n is an integer from 0 to 2 in each unit indicated by subscript b; with the proviso that at least two of R 5 are aliphatically unsaturated groups; each Z is independently H or an alkyl group; and wherein a, b, c, d, and e are mole fractions satisfying the following: a>0; b>0; c≥0; d≥0; 0≤e≤0.05; and a+b+c+d+e=1.

6 . The composition of claim 5 , wherein c>0 and/or d>0 such that the (A) organopolysiloxane is branched or resinous.

7 . The composition of claim 1 , wherein the (A) organopolysiloxane is represented by the following average formula:
(R 4 3-m R 5 m SiO 1/2 ) 2 (R 4 2-n R 5 n SiO 2/2 ) y wherein y is an integer from 10 to 10,000; each R 4 is an independently selected substituted or unsubstituted hydrocarbyl group free from aliphatic unsaturation; each R 5 is independently R 4 or an aliphatically unsaturated group having from 1 to 10 carbon atoms; each subscript m is independently an integer from 0 to 3; each subscript n is an integer from 0 to 2 in each unit indicated by subscript y; with the proviso that at least two of R 5 are aliphatically unsaturated groups.

8 . The composition of claim 7 , wherein each subscript m is 1 and each subscript n is 0 such that the (A) organopolysiloxane is represented by the following average formula:
(R 4 2 R 5 SiO 1/2 ) 2 (R 4 2 SiO 2/2 ) y .

9 . The composition of claim 1 , wherein the (B) organopolysiloxane is represented by the following average formula:
(R 4 3-o R 6 o SiO 1/2 ) f (R 4 2-p R 6 p SiO 2/2 ) g (R 6 SiO 3/2 ) h (SiO 4/2 ) i (ZO 1/2 ) j wherein each R 4 is an independently selected substituted or unsubstituted hydrocarbyl group free from aliphatic unsaturation; each R 6 is independently R 4 or comprises a mercapto group; each subscript o is independently an integer from 0 to 3 in each unit indicated by subscript f; each p is independently an integer from 0 to 2 in each unit indicated by subscript g; with the proviso that at least two of R 6 independently comprise mercapto groups; each Z is independently H or an alkyl group; wherein f, g, h, i, and j are mole fractions satisfying the following: f>0; g>0; h≥0; i≥0; 0≤j≤0.05 and f+g+h+i+j=1.

10 . The composition of claim 9 , wherein h>0 and/or i>0 such that the (B) organopolysiloxane is branched or resinous.

11 . The composition of claim 1 , wherein the (B) organopolysiloxane is represented by the following average formula:
(R 4 3-o R 6 o SiO 1/2 ) 2 (R 4 2-p R 6 p SiO 2/2 ) z wherein z is an integer from 10 to 10,000; each R 4 is an independently selected substituted or unsubstituted hydrocarbyl group free from aliphatic unsaturation; each R 6 is independently R 4 or comprises a mercapto group; each subscript o is independently an integer from 0 to 3; each p is independently an integer from 0 to 2 in each unit indicated by subscript z; with the proviso that at least two of R 6 independently comprise mercapto groups.

12 . The composition of claim 11 , wherein subscript o is 0 and the (B) organopolysiloxane is represented by the following average formula:
(R 4 3 SiO 1/2 ) 2 (R 4 R 6 SiO 2/2 ) z′ (R 4 2 SiO 2/2 ) z″ wherein z′ is an integer from 2 to 100, subscript z″ is an integer of from 8 to 9998, with the proviso that 10≤z′+z″≤10,000.

13 . The composition of claim 1 , wherein: (i) the (E) tetraorthosilicate comprises tetraethyl orthosilicate (TEOS) and/or tetrapropyl orthosilicate (TPOS); or (ii) the (D) acryloxy-functional silane comprises 3-methacryloxypropyl trimethoxysilane; or (iii) both (i) and (ii).

14 . A method of forming a cured product, the method comprising:
applying the composition of claim 1 to a surface of a substrate; and irradiating the composition on the substrate to give the cured product.

15 . A cured product disposed on a substrate formed in accordance with the method of claim 14 .

Assignees

• Dow Silicones Corp

Inventors

• Liu Junying
• Zhu Bizhong
• Shephard Nick Evan

Classifications

• C08K5/5425

  containing at least one C=C bond · CPC title

• C08K5/5415

  containing at least one Si—O bond · CPC title

• C08K5/0025

  Crosslinking or vulcanising agents; including accelerators · CPC title

• C08L83/00

  Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers · CPC title

• C09D183/04

  Polysiloxanes · CPC title