# US 4,391,963 A · Organopolysiloxane photosensitizers and methods for their preparation

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- Number: US 4,391,963 A
- Document ID: US4391963A
- Status: Granted
- Kind: A
- Application number: 06/382,504
- Filed: 1982-05-27
- Granted: 1983-07-05
- Earliest claimed: 1981-06-18
- Assignees: Toray Silicone Company, Ltd.
- Inventors: Akihiko Shirahata
- Web page: https://patentgrep.com/patent/US4391963A

## CPC

- G03F 7/0757: {Macromolecular compounds containing Si-O, Si-C or Si-N bonds (G03F7/0752 takes precedence)}
- C08G 77/14: containing silicon bound to oxygen-containing groups
- C08G 77/38: Polysiloxanes modified by chemical after-treatment
- C08L 83/04: Polysiloxanes
- C08G 77/12: containing silicon bound to hydrogen
- C08G 77/18: to alkoxy or aryloxy groups
- C08G 77/20: containing silicon bound to unsaturated aliphatic groups
- C08G 77/24: halogen-containing groups
- C08G 77/26: nitrogen-containing groups
- C08G 77/28: sulfur-containing groups
- C08G 77/70: {Siloxanes defined by use of the MDTQ nomenclature}
- Y10S 522/904: Monomer or polymer contains initiating group
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Novel photosensitizers are disclosed which are particularly useful in photopolymerizable organopolysiloxane and silicone resins. The photosensitizers are themselves organopolysiloxanes which contain at least one silicon-bonded benzoin-containing radical. Synthesis methods are disclosed for preparing these photosensitizers which employ, as starting materials, an alkenyl-substituted benzoin and a silicon compound containing at least one silicon-bonded hydrogen atom.

## Claims

### Claim 1

An organopolysiloxane photosensitizer comprising an average of at least two siloxane units, of which at least an average of one siloxane unit per organopolysiloxane molecule has the formula Q.sub.a R.sub.b.sup.5 SiO.sub.(4-a-b)/2, wherein Q denotes a benzoin-containing group having the formula ##STR17## R.sup.1 and R.sup.2 each denote, independently, a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having from 1 to 10 carbon atoms, an alkoxy group, a thioalkoxy group, an amino group or a dialkylamino group; R.sup.3 denotes a hydrogen atom or a monovalent hydrocarbon group having from 1 to 10 carbon atoms; R.sup.4 denotes a divalent hydrocarbon group having from 2 to 10 carbon atoms; R.sup.5 denotes a monovalent hydrocarbon group having from 1 to 10 carbon atoms or a halogenated monovalent hydrocarbon group; m is an integer of from 1 to 5, n is an integer of from 1 to 5, a is an integer of from 1 to 3, b is an integer of from 0 to 2 and a+b is an integer of from 1 to 3.

### Claim 2 (depends on 1)

A composition according to claim 1 wherein any siloxane unit in the organopolysiloxane photosensitizer molecules not bearing a Q group has the formula R.sub.c.sup.5 H.sub.d SiO.sub.(4-c-d)/2 wherein c, d and c+d are integers of from 0 to 3.

### Claim 3 (depends on 2)

A composition according to claim 2 wherein the average number of Q groups in the organopolysiloxane molecule is equal to from 0.2% to 50% of the total number of Q groups plus R.sup.5 groups in the organopolysiloxane molecule.

### Claim 4 (depends on 1, 2, 3)

A composition according to claim 1, 2 or 3 wherein each R.sup.5 denotes a methyl group and a has a value of 1.

### Claim 5 (depends on 4)

A composition according to claim 4 wherein the organopolysiloxane photosensitizer has the formula ##STR18## wherein x, y and z denote integers whose sum has a value of less than 1000.

### Claim 6

A method for preparing an organopolysiloxane photosensitizer comprising an average of at least two siloxane units, of which at least an average of one siloxane unit per organopolysiloxane molecule has the formula Q.sub.a R.sub.b.sup.5 SiO.sub.(4-a-b)/2, said method comprising reacting, by a hydrosilylation reaction, an alkenyl-substituted benzoin reactant having the formula ##STR19## and an organohydrogenpolysiloxane reactant containing at least than two siloxane units and at least one silicon-bonded hydrogen atom per molecule, wherein Q denotes a benzoin-containing group having the formula ##STR20## at each occurrence R.sup.1 and R.sup.2 denote, independently, a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having from 1 to 10 carbon atoms, an alkoxy group, a thioalkoxy group, an amino group or a dialkylamino group; R.sup.3 denotes a hydrogen atom or a monovalent hydrocarbon group having from 1 to 10 carbon atoms; R.sup.4 denotes a divalent hydrocarbon group having from 2 to 10 carbon atoms; R.sup.5 denotes a monovalent hydrocarbon group having from 1 to 10 carbon atoms or a halogenated monovalent hydrocarbon group; R.sup.6 denotes an aliphatically unsaturated monovalent hydrocarbon group having the same number of carbon atoms as the R.sup.4 group; m is an integer of from 1 to 5, n is an integer of from 1 to 5, a is an integer of from 1 to 3, b is an integer of from 0 to 2 and a+b is an integer of from 1 to 3 whereby the R.sup.6 group becomes the R.sup.4 group during said reaction.

### Claim 7 (depends on 6)

A method according to claim 6 wherein the organohydrogenpolysiloxane consists of siloxane units having the formula R.sub.c.sup.5 H.sub.d SiO.sub.(4-c-d)/2 wherein c, d and c+d are integers of from 0 to 3.

### Claim 8 (depends on 7)

A method according to claim 7 wherein each R.sup.5 denotes a methyl group.

### Claim 9 (depends on 6, 7, 8)

A method according to claim 6, 7 or 8 wherein the organohydrogenpolysiloxane has the formula R.sub.3.sup.5 SiO(R.sub.2.sup.5 SiO).sub.x (R.sup.5 HSiO).sub.w SiR.sub.3.sup.5 wherein x and w denote integers whose sum has a value of less than 1000.

### Claim 10 (depends on 9)

A method according to claim 9 wherein the alkenyl-substituted benzoin reactant has the formula ##STR21##

### Claim 11

A method for preparing an organopolysiloxane photosensitizer comprising an average of at least two siloxane units, of which an average of at least one siloxane unit per organopolysiloxane molecule has the formula Q.sub.a R.sub.b.sup.5 SiO.sub.(4-a-b)/2, said method comprising
(A) reacting, by a hydrosilylation reaction to form an adduct, an alkenyl-substituted benzoin reactant having the formula ##STR22## and a silane bearing at least one silicon-bonded hydrogen atom and at least one silicon-bonded hydrolyzable group or a siloxane bearing at least two siloxane units and at least one silicon-bonded hydrogen atom; and
(B) polymerizing the adduct or copolymerizing the adduct with another silane bearing at least one silicon-bonded hydrolyzable radical or with a siloxane, both being free of Q groups, to provide the organopolysiloxane photosensitizer, wherein Q denotes a benzoin-containing group having the formula ##STR23## at each occurrence R.sup.1 and R.sup.2 denote, independently, a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having from 1 to 10 carbon atoms, an alkoxy group, a thioalkoxy group, an amino group or a dialkylamino group; R.sup.3 denotes a hydrogen atom or a monovalent hydrocarbon group having from 1 to 10 carbon atoms; R.sup.4 denotes a divalent hydrocarbon group having from 2 to 10 carbon atoms; R.sup.5 denotes a monovalent hydrocarbon group having from 1 to 10 carbon atoms or a halogenated monovalent hydrocarbon group; R.sup.6 denotes an aliphatically unsaturated monovalent hydrocarbon group having the same number of carbon atoms as the R.sup.4 group; m is an integer of from 1 to 5, n is an integer of from 1 to 5, a is an integer of from 1 to 3, b is an integer of from 0 to 2 and a+b is an integer of from 1 to 3; the R.sup.6 group becoming the R.sup.4 group during said hydrosilylation reaction.

### Claim 12 (depends on 11)

A method according to claim 11 wherein the siloxane bearing at least two siloxane units and at least one silicon-bonded hydrogen atom consists of siloxane units having the formula R.sub.c.sup.5 H.sub.d SiO.sub.(4-c-d)/2 wherein c, d and c+d are integers of from 0 to 3.

### Claim 13 (depends on 12)

A method according to claim 12 wherein the siloxane bearing at least two siloxane units and at least one silicon-bonded hydrogen atom is tetramethyltetrahydrocyclotetrasiloxane having the formula (CH.sub.3 HSiO).sub.4.

### Claim 14 (depends on 11)

A method according to claim 11 wherein the silane bearing at least one silicon-bonded hydrogen atom and at least one silicon-bonded hydrolyzable group has the formula R.sub.e.sup.5 HSiZ.sub.3-e wherein e is an integer of from 0 to 2 and Z denotes a chlorine atom, an alkoxy group or an acyloxy group.

### Claim 15 (depends on 14)

A method according to claim 14 wherein R.sup.5 denotes a methyl radical and e has a value of 1.

### Claim 16 (depends on 11, 12, 13, 14, 15)

A method according to claim 11, 12, 13, 14 or 15 wherein the alkenyl-substituted benzoin reactant has the formula ##STR24##