JPH04268378A - Photocurable silicone composition - Google Patents

Abstract

PURPOSE:To improve curability by adding a curing catalyst to a reaction product of a specific silicone compd. with an organopolysiloxane having terminal silanol groups. CONSTITUTION:1mol of a silicone compd. having an o-nitrobenzyloxy group of formula I (wherein R1 is 1-1OC alkyl, 2-10C alkenyl, or 6-1OC aryl; X and Y are each H, halogen, amino, aminoxy, 1-1OC alkoxy, amido, acyloxy, 2-1OC alkenyloxy, or 3-1OC ketoxime; and n is 0 or 1) is reacted with 0.5-2mol of an organopolysiloxane having terminal silanol groups of formula II [wherein R2 and R3 are each 1-1OC (substd.) alkyl, alkenyl, or 6-1OC (substd.) aryl; and m is 2 or higher] to give a reaction product. 0.1-10 pts.wt. curing catalyst is added to 100 pts.wt. the product.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable silicone composition, which can be used for coatings, release materials, lithographic printing plate materials, and the like.

0002

BACKGROUND OF THE INVENTION Conventionally, the following photocurable silicone compositions are known.

(1) Acrylic or methacrylic group-containing silicone compositions disclosed in Japanese Patent Publication No. 49-39200.

(2) Maleimide group-containing silicone compositions disclosed in Japanese Patent Publication No. 5302/1983.

(3) Epoxy group-containing silicone compositions disclosed in US Pat. No. 4,279,717.

(4) Polyene-polythiol-containing silicone compositions disclosed in US Pat. No. 4,064,027.

However, (1) is susceptible to curing inhibition by air, (2) and (3) require materials that are difficult to obtain, and (4) requires a thiol component that remains in the cured product. There were problems in that there was an unpleasant odor associated with the curing process, and the curing speed was not sufficient. Furthermore, (1) to (4
), in order to obtain a sufficient curing speed, it is necessary to increase the concentration of photoreactive groups in the silicone, which reduces the releasability and ink repellency derived from the silicone structure. There was a problem with letting it work.

[0008]

OBJECTS OF THE INVENTION The object of the present invention is to solve the above-mentioned problems, to obtain a sufficient photocuring speed, and to avoid deterioration of releasability and ink repulsion. An object of the present invention is to provide a photocurable silicone composition that can be easily and inexpensively produced.

[0009]

[Means for Solving the Problems] The objects of the present invention are achieved by the following configuration.

(A) Silicone compound represented by general formula (I)

[0011]

[Chemical formula 3]

(In the formula, R1 is an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and an alkenyl group having 6 to 10 carbon atoms.
at least one selected from the group of 10 aryl groups, and X and Y are each a hydrogen atom, a halogen atom, an amino group, an aminooxy group, an alkoxy group having 1 to 10 carbon atoms,
It is at least one selected from the group consisting of an amide group, an acyloxy group, an alkenyloxy group having 2 to 10 carbon atoms, and a ketoxime group having 3 to 10 carbon atoms, and each of them may be the same or different. n is 0 or 1. )and(
B) Organopolysiloxane having a silanol structure at the terminal represented by general formula (II)

[0013]

[C4]

(In the formula, R2 and R3 are a substituted or unsubstituted alkyl group or alkenyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms.
is an integer greater than or equal to 2. ) A photocurable silicone composition prepared by adding (C) a curing catalyst to the reactant.

That is, the present invention involves the photodecomposition of a silicone compound having a specific o-nitrobenzyloxy group,
The present invention was achieved by discovering that a photocurable silicone composition that utilizes a crosslinking reaction of a silanol structure by a curing catalyst exhibits remarkable effects.

General formula (I) of (A) used in the present invention

[0017]

[C5]

In the formula, R1 is an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkenyl group having 6 carbon atoms.
It is at least one kind selected from the group of ~10 aryl groups. In addition, X and Y are each a hydrolyzable functional group, such as a hydrogen atom, a halogen atom, an amino group, an aminooxy group, an alkoxy group having 1 to 10 carbon atoms, an amide group, an acyloxy group, and an alkenyloxy group having 2 to 10 carbon atoms. and carbon number 3
at least one selected from the group of ~10 ketoxime groups
species, each of which may be the same or different, n
is 0 or 1.

Specific examples of the silicone compound represented by the general formula (I) include diacetoxymethyl (o-nitrobenzyloxy)silane, diacetoxyethyl (o-nitrobenzyloxy)silane, and diacetoxybutyl (o-nitrobenzyloxy)silane.
-nitrobenzyloxy)silane, diacetoxyhexyl(o-nitrobenzyloxy)silane, diacetoxyoctyl(o-nitrobenzyloxy)silane, diacetoxyvinyl(o-nitrobenzyloxy)silane, diacetoxydi(o-nitrobenzyloxy)silane ) silane, methyl(o-nitrobenzyloxy)dichlorosilane, dimethoxymethyl(o-nitrobenzyloxy)silane,
Dimethoxyethyl(o-nitrobenzyloxy)silane, dimethoxybutyl(o-nitrobenzyloxy)silane, diethoxymethyl(o-nitrobenzyloxy)silane, diethoxyethyl(o-nitrobenzyloxy)
Silane, dimethoxydi(o-nitrobenzyloxy)silane, diethoxydi(o-nitrobenzyloxy)silane, dibutoxydi(o-nitrobenzyloxy)silane, dihexyloxydi(o-nitrobenzyloxy)silane, di(methylethylketoxime)(o- nitrobenzyloxy)silane, di(methylethylketoxime)
Examples include, but are not limited to, di(o-nitrobenzyloxy)silane, methyldi(methylethylketoxime)(o-nitrobenzyloxy)silane, diisopropenylmethyl(o-nitrobenzyloxy)silane, and the like.

[0020] Furthermore, the organopolysiloxane having a silanol structure at the terminal represented by the general formula (II) of (B) is
Those having a molecular weight of 1,000 to 1,000,000 are preferred. Specific examples include dimethylpolysiloxane, diethylpolysiloxane, dibutylpolysiloxane, dihexylpolysiloxane, dioctylpolysiloxane, methylethylpolysiloxane, methylphenylpolysiloxane, methylvinylpolysiloxane, and mixtures of these polysiloxanes. However, those containing more than 60% of methyl groups are particularly preferred.

The reaction between the silicone compound represented by the general formula (I) and the organopolysiloxane having a silanol structure at the terminal represented by the general formula (II) is as shown in the formula (III).

[0022]

[C6]

(In the formula, R1, Any catalyst may be used, but tin or titanium catalysts are particularly preferred. Specific examples include dimethyltin diacetate and diethyltin diacetate.
Examples include dibutyltin diacetate, dihexyltin diacetate, dibutyltin dilaurate, dibutyltin dimaleate, tetramethoxytitanium, tetraethoxytitanium, and tetrabutoxytitanium.

One of the characteristics of the present invention is that a silico-silico-containing compound having an o-nitrobenzyloxy group as shown in formula (IV)
This method utilizes photodecomposition of carbon compounds and crosslinking reactions of silanol structures using curing catalysts.

[0025]

[C7]

(In the formula, R1 is the same as described above.) First, as shown in formula (III), a silicone compound having an o-nitrobenzyloxy group and an organometallic compound having a silanol structure at the end are combined. It reacts with polysiloxane to produce an organopolysiloxane having an o-nitrobenzyloxy group in its molecule. Next, by adding a curing catalyst to this organopolysiloxane and irradiating it with ultraviolet light, etc., the o-nitrobenzyloxy group is photodecomposed as shown in formula (IV), and o-nitrosobenzaldehyde and silanol structure are formed. is produced, but the silanol structure produced here causes a crosslinking reaction by the curing catalyst and becomes rubber.

The proportion of each component in the photocurable silicone composition of the present invention is not particularly limited, but is preferably a silicone compound represented by general formula (I) and a silicone compound represented by general formula (II). 0.1 to 10 parts by weight of a curing catalyst is added to 100 parts by weight of a reactant obtained by reacting an organopolysiloxane having a silanol structure at a molar ratio of 1:0.5 to 1:2. Good.

In addition to the above-mentioned components, it is also possible to add 0.1 to 10 parts by weight of a crosslinking agent such as methyltriacetoxysilane prior to irradiation with ultraviolet rays or the like to effect crosslinking in advance.

As a preferred application example of the photocurable silicone composition of the present invention, this photocurable silicone composition is applied to a thin film having a thickness of 0.1 to 100μ, more preferably 0.5 to 50μ. Examples include plate materials for waterless planographic printing obtained by forming a transparent coating.

[0030]

[Examples] Hereinafter, the present invention will be explained in detail using examples.

Example 1 11 g of "PS340" manufactured by Chisso Corporation (dimethylpolysiloxane having a silanol structure at both ends) and 2 g of diacetoxymethyl (o-nitrobenzyloxy)silane were reacted in 20 g of toluene at room temperature for 3 hours. I let it happen. (Hereinafter, the polymer obtained by this reaction will be abbreviated as Polymer (I).) Thickness: 0.
A 5 μm thick silicone coating having the following composition was formed on a 3 mm aluminum plate.

(a) Polymer (I)

100 parts by weight (b) dibutyltin diacetate

0.2 parts by weight (c) Toluene

325 parts by weight of the above coating film
When exposed for 60 seconds using a W high-pressure mercury lamp, a sufficiently cured film was obtained.

Comparative Example 1 A silicone coating film with a thickness of 5μ and having the following composition was formed on an aluminum plate with a thickness of 0.3mm.

(a) "S" manufactured by Toray Dow Corning Silicone Co., Ltd.
H413X” (vinyl group-containing polydimethylsiloxane)

100 parts by weight (b) “P” manufactured by Chisso Corporation
S927” (polymercaptopropylmethylsiloxane)

10 parts by weight (c) dimethyldiacetoxysilane
12 parts by weight (d) “Irgacure 651” manufactured by Ciba Geigy
5 parts by weight (e) toluene

325 parts by weight Example 1
Similarly, the above coating film was exposed using a 3 kW high pressure mercury lamp, but a sufficiently cured film could not be obtained even after 300 seconds of exposure.

Example 2 20 g of “PS341” (dimethylpolysiloxane with silanol structure at both ends) manufactured by Chisso Corporation and diacetoxydi(
2.1 g of o-nitrobenzyloxy)silane was reacted in 34 g of toluene at room temperature for 3 hours. (Hereinafter, the polymer obtained by this reaction will be abbreviated as Polymer (II).) A coating film similar to that in Example 1 was prepared using Polymer (II) instead of Polymer (I) in Example 1. He made a profit and obtained the original printing plate.

A positive film with an image of 150 lines/inch was vacuum-adhered to the surface of this coating film, exposed for 55 seconds using a 3kW high-pressure mercury lamp, and developed with xylene, resulting in an image faithful to the positive film. Formed. When printing was carried out using this printing plate, it was found that printed matter that faithfully reproduced the image of the positive film was obtained, and that it was possible to print more than 10,000 sheets.

Example 3 40 g of "PS342.5" (dimethylpolysiloxane having a silanol structure at both ends) manufactured by Chisso Corporation and 0.9 g of dimethoxydi(o-nitrobenzyloxy)silane were mixed in 63 g of toluene at 60°C. The reaction was carried out for 3 hours (hereinafter, the polymer obtained by this reaction is abbreviated as polymer (III)). After similar exposure and development, 6
An image faithful to a positive film was formed in 5 seconds. When printing was carried out using this printing plate in the same manner as in Example 2, printed matter that faithfully reproduced the image of the positive film was obtained, and it was found that printing of 9000 sheets or more was possible.

[0038]

Effects of the Invention Since the present invention is constructed as described above, it is possible to obtain a photocurable silicone composition that exhibits high curability against irradiation with ultraviolet rays and the like.

Claims (1)

[Claims] Claim 1: (A) A silicone compound represented by the general formula (I) [Formula 1] (wherein R1 is an alkyl group having 1 to 10 carbon atoms, 2 carbon atoms
~10 alkenyl groups, and aryl groups having 6 to 10 carbon atoms
X and Y are each a hydrogen atom, a halogen atom, an amino group, an aminooxy group, an alkoxy group having 1 to 10 carbon atoms, an amide group, an acyloxy group, and a group having 2 to 10 carbon atoms. It is at least one selected from the group consisting of 10 alkenyloxy groups and 3 to 10 carbon atoms ketooxime groups, which may be the same or different. n is 0 or 1. ) and (B) an organopolysiloxane having a silanol structure at the terminal represented by the general formula (II) (wherein R2 and R3 are substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms, An alkenyl group, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, m is an integer of 2 or more), and (C) a curing catalyst is added to the reactant. A photocurable silicone composition.