JPH0436353A - Photocurable organopolysiloxane composition and its cured product - Google Patents

Abstract

PURPOSE:To obtain the title composition improved in storage stability, UV curability and adhesiveness by mixing a specified organopolysiloxane with an alkoxysilane compound, an acyloxysilane and a photopolymerization initiator. CONSTITUTION:100 pts.wt. organopolysiloxane having at least one group of formula I [wherein R<1> is H or methyl; R<2> to R<4> are each an (un) substituted monovalent hydrocarbon group; R<5> is O or a bivalent hydrocarbon group; and (a) and (b) are each 1-3] in the molecule is mixed with 0.1-10 pts.wt. alkoxysilane compound of formula II [wherein R<6> is an (un)substituted monovalent hydrocarbon group; R<7> is a bivalent hydrocarbon group and R<8> is H or methyl], 0.01-10 pts.wt. acyloxysilane of formula III [wherein R<9> to R<11> are each an (un) substituted monovalent hydrocarbon group; (c) is 1-3; (d) is 0-3; and (c+d)= 1-4] and 0.01-10 pts.wt. photopolymerization initiator (e.g. acetophenone).

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a photocurable organopolysiloxane composition, which has particularly excellent storage stability, is cured by ultraviolet irradiation, and is highly resistant to glass, metals, plastics, etc. Adhesives,
The present invention relates to a photocurable organopolysiloxane composition useful as a sealing agent, coating agent, and botting agent, and a cured product thereof.

(Prior art) It is well known that when organopolysiloxane is heated in the presence of an organic peroxide, it becomes a silicone rubber elastic body with excellent heat resistance, cold resistance, weather resistance, and electrical properties. Some of these organosiloxanes are known to be cured by light irradiation in the presence of a photoinitiator.

As for this photocurable organopolysiloxane composition, for example, one is known which is obtained by curing a vinyl group-containing polysiloxane and a mercapto group-containing polysiloxane through a photoradical addition reaction (Japanese Patent Publication No.
2-40334, JP-A-60-104158), but this has problems with the odor of the mercapto group and the corrosivity of metals. Furthermore, for compositions that harden by irradiation with light, a composition comprising an acrylic group-containing polysiloxane and a sensitizer has been proposed (Japanese Patent Publication No. 53-36
515, JP-A No. 60-215009),
In order to obtain a rubber-like elastic body, it is necessary to use a linear polymer with a high molecular weight, so the amount of acrylic groups located at the end is relatively small, resulting in poor curing properties, and when in contact with air, Due to the disadvantage that the surface portion of the rubber hardly hardens due to the inhibition of hardening by oxygen, only resin-like materials with a relatively large amount of acrylic groups have been put into practical use, and a satisfactory rubber-like elastic material has not been obtained. .

(Problem to be Solved by the Invention) Therefore, the present inventors first used a novel compound called acryloxyalkylsilanol to combine a polysiloxane with a plurality of acrylic groups introduced at the ends of a linear polymer and a sensitizer. proposed a composition consisting of
(Refer to Publication No. 3911) However, although this product provides a practical silicone rubber elastic body, it was found that it was not suitable for various adhesives and seals because it did not adhere to glass or metal at all. When an organic silicon compound having an amino group or an acrylic group was added to this,
We found that it exhibits adhesion to glass, but it takes several hours for glass adhesion to develop.
However, it had the disadvantage that its adhesive strength to materials other than glass was not strong enough.

(Means for Solving the Problems) The present invention relates to a photocurable organopolysiloxane composition and a cured product thereof that solve the above-mentioned disadvantages. or methyl group, R2, R3,
R4 is an unsubstituted or substituted same or different monovalent hydrocarbon group, R5 is an oxygen atom or a divalent hydrocarbon group, and a and b are 1.2 or 3) at least one group in one molecule. 100 parts by weight of organopolysiloxane, 2)
- Alkoxysilane compound represented by the formula (where RG is the same or different unsubstituted or substituted monovalent hydrocarbon group, R7 is a divalent hydrocarbon group, and R8 is a hydrogen atom or a methyl group) 0.
1 to 10 parts by weight, 3) - Formula (where Rg, R10, R
11 is the same or different unsubstituted or substituted monovalent hydrocarbon group, C is 1.2.3 or 4, d is Oll, 2, or 3, and C0d is 1.2.3 or 4 A photocurable organopolysiloxane comprising 0.01 to 10 parts by weight of an acyloxysilane represented by This relates to a cured product.

That is, the present inventors conducted various studies to develop a photocurable organopolysiloxane composition with particularly excellent adhesive properties and storage stability.
) and a photopolymerization initiator as the fourth component, and acrylic as the second component represented by the above formulas (2) and (3). When a group-containing alkoxysilane and an acyloxysilane as a third component are added,
This composition cures in a short time when exposed to ultraviolet rays, and unexpectedly develops adhesive strength instantaneously.
They discovered that it adheres well to metals, plastics, etc., and completed research on the types and amounts of each component used. This will be explained in further detail below.

(Function) The present invention relates to a photocurable organopolysiloxane whose main ingredient is an organopolysiloxane containing an acryloxyorganosilyl group, and a cured product thereof.

The organopolysiloxane as the first component constituting the composition of the present invention has a general formula in the molecule, where R1 is a hydrogen atom or a methyl group, and R2, R3, and R4 are methyl, ethyl, or propyl groups. , alkyl groups such as butyl groups,
Cycloalkyl groups such as cyclohexyl groups, vinyl groups,
Alkenyl groups such as allyl groups, aryl groups such as phenyl groups and tolyl groups, chloromethyl groups in which some or all of the hydrogen atoms bonded to carbon atoms of these groups are substituted with halogen atoms, cyano groups, etc., trifluoro Selected from propyl group, cyanoethyl group, etc., usually with 1 carbon number
~10, preferably the same or different unsubstituted or substituted hydrocarbon groups having 1 to 8 carbon atoms, R5 is an oxygen atom or a divalent hydrocarbon group usually having 1 to 8 carbon atoms, a and b are each It is said to have at least one acryloxyorganosilyl group of 1.2 or 3, but this is a compound previously created by the present inventors,
Examples of this include the following.

(m and n in the above formula are integers of 1 or more).

Next, the alkoxysilane compound as the second component constituting the composition of the present invention is added to impart adhesiveness to this composition, and this is expressed by the general formula % (2). and R6 is the same as R2, R゛, R4 described above,
Same or different unsubstituted or substituted monovalent hydrocarbon groups, usually having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms.

R7 usually has 1 to 20 carbon atoms, preferably 1 to 8 carbon atoms.
The divalent hydrocarbon group R8 is required to be a hydrogen atom or a methyl group. Examples of the acrylic group-containing alkoxysilane include those represented by the following formula %.

The amount of this acrylic group-containing alkoxysilane is the same as the organopolysiloxane as the first component described above.
If the amount is less than 0.1 parts by weight, the silicone rubber made from the resulting composition will not exhibit sufficient adhesion, and if it is more than 10 parts by weight, the curing of this composition will be adversely affected. A range of 0.1 to 10 parts by weight is required.

Furthermore, acyloxysilane as a third component constituting the composition of the present invention is added to accelerate the rate at which the adhesive strength of this composition develops, and is represented by the general formula R9. , R", R" are the above-mentioned R2, R3R4
Similar to, usually 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms
the same or different unsubstituted or substituted monovalent hydrocarbon groups,
C is 1, 2.3, or 4, d is Oll, 2, or 3, and C+d is 1.2.3 or 4, and examples thereof include the following.

If the amount of this compound is less than 0.0 parts by weight per 100 parts by weight of the organopolysiloxane as the first component, the adhesive strength of the silicone rubber elastic body obtained from this composition will be weak, If the amount exceeds 0.01 to 10 parts by weight, the curing of the composition will be adversely affected.

Furthermore, the photopolymerization initiator as the fourth component constituting this composition is for promoting the photopolymerization of the acrylic group in the organopolysiloxane as the first component, which is known in the art. It is well known,
These include acetophenone, propiophenone, benzophenone, fluorein, benzaldehyde, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-methylacetophenone, 3-pentylacetophenone, 4-methoxyacetophenone, 3-
Bromoacetophenone, 4-allylacetophenone, p
-Diacetylbenzene, 3-methoxybenzophenone,
4-methylbenzophenone, 4-chlorobenzophenone, 4.4'dimethoxybenzophenone, 4-chloro-4
'Benzylbenzophenone, 3-chloroxanthone,
3,9-dichloroxanthone, 3-chloro-8-nonylxanthone, benzoin, benzoin methyl ether, benzoin butyl ether, bis(4-dimethylaminophenyl) ketone, benzyl methoxy ketal, 2
-chlorothioxanthone, diethylacetophenone,
Examples include 1-hydroxycyclohexylphenylketone, 2-methyl-[4-(methylthio)phenyl]2-morpholino-1-propanone, and 2,2-dimethoxy-2-phenylacetophenone. In addition, this blending amount is the organopolysiloxane 1 as the first component described above.
If the amount is less than 0.01 parts by weight, there will be no effect, and if it is more than 10 parts by weight, the silicone rubber obtained will have low strength and the physical properties of the cured product will deteriorate. It is necessary to range from .01 to 10 parts by weight.

The composition of the present invention can be obtained by uniformly mixing predetermined amounts of the above-mentioned first to fourth components. Depending on the situation, a fumed silicate filler that does not inhibit photocuring may be added, and it is also optional to add a thixotropy agent, a heat resistance improver, a coloring agent, etc. for the purpose of adjusting the physical properties. .

Since the organopolysiloxane as the first component of the composition of the present invention thus obtained contains a photopolymerizable acryloxyorganosilyl group, it can be used in a short time of 1 to 20 seconds when irradiated with ultraviolet rays. It hardens easily to become silicone rubber, and the rubber elastic body of the present invention thus obtained has excellent heat resistance, weather resistance, and low-temperature properties that are characteristic of silicone rubber, and is suitable for various materials. It is useful as an adhesive for electrical and electronic parts, optical materials, potting materials, coating materials, sealing materials, etc. because it adheres well.

(Example) Next, examples of synthesis of organopolysiloxane as the first component constituting the composition of the present invention and examples of the present invention will be given. This shows the measured values of .

Synthesis Example 1 A 2Q reaction flask equipped with a thermometer, a condenser, and a stirrer was used to react at a temperature of 1.0 OOcS for 2 hours, and then nitrogen gas was passed through the liquid at the same temperature to remove unreacted methyl. Dichlorosilane was removed from the system.

Next, add 23.8 g of triethylamine and 2.6 g of triethylamine to this N.
After adding 0.4 g of -di-t-butyl-4-methylphenol, 17.2 g of α-acryloxymethyldimethylsilanol was added dropwise over 30 minutes, and after reacting at 60°C for 2 hours, 500 g of toluene was added. The resulting salt was spread out and stripped under conditions of 100°C/2 Hg to remove toluene and excess triethylamine under reduced pressure. Dimethylpolysiloxane (
Add 1,000 g of vinyl having a vinyl value of 0.018 mol/100 g, heat it at 120°C for 2 hours under a nitrogen gas stream to dehydrate it, and after cooling, add an isopropyl alcohol solution of chloroplatinic acid (platinum amount: 2% by weight). 0.1 g and 12.3 g of methyldichlorosilane were added to obtain 920 g of a colorless and transparent organopolysiloxane designated by 90 (hereinafter abbreviated as polysiloxane-I).

Synthesis Example 2 0.4 g of 2.6-di-t-butyl-4-methylphenol with a formula with a viscosity of 3,400 cS was added to a 2Q reaction flask equipped with a thermometer, condenser, and stirrer, and then α-acryloxy 34.1g of methyldimethylsilanol
After reacting at 60°C for 2 hours, the salt produced was separated in a furnace and stripped under the conditions of 100°C/2 kg Hg to remove excess triethylamine under reduced pressure. 1.000 g of α,ω-divinyldimethyldiphenylpolysiloxane (vinyl value 0.018 mol/100 g, phenyl group content 30 mol%) was heated at 120°C for 2 hours under a nitrogen gas stream to dehydrate, and then cooled. Add 0.1 g of an isopropyl alcohol solution of chloroplatinic acid (platinum amount: 2% by weight) and 12.2 g of methyldichlorosilane to the second solution, react at 50°C for 1 hour, and then at 80°C for 3 hours, and then add the same solution. Unreacted methyldichlorosilane was removed from the system by flowing nitrogen gas into the solution at a certain temperature.

Next, 900 g of a colorless and transparent organopolysiloxane (hereinafter abbreviated as polysiloxane-■) represented by N and 21.5 g of triethylamine was obtained.

Example 1, Comparative Example 1 To 1100 parts of the polysiloxane obtained in Synthesis Example 1 described above,
2 parts of γ-methacryloxypropyltrimethoxysilane (hereinafter abbreviated as acrylic silane I) and 0 parts of methyltriacetoxysilane (hereinafter abbreviated as acyloxysilane 1).
5 parts and 2.5 parts of 1-hydroxycyclohexylphenyl ketone (hereinafter abbreviated as photopolymerization initiator I) were added and mixed uniformly to prepare siloxane composition 1, and for comparison, acyloxy in the above A siloxane composition (2) was prepared by adding 0.5 parts of acrylic acid in place of silane 1.

Next, a sample for measuring glass shear adhesive strength as shown in Figure 1 was made from the siloxane compositions 1 and 2, and this was exposed to an ultraviolet irradiation device ASE-20 [part name manufactured by Nippon Battery ■].
The composition was cured by irradiating it with ultraviolet rays three times at a speed of 1 m/min, and the glass shear adhesive strength was measured 1 hour after curing, and the composition was heated and stored at 70°C for 5 parts. When similar tests were conducted, the results shown in Table 1 were obtained.

Table 1 Examples 2 to 4, Comparative Examples 2 to 4 To 100 parts of the polysiloxane ■ obtained in Synthesis Example 2 described above,
Acrylic silane I, γ-acryloxypropyltrimethoxysilane (hereinafter abbreviated as acrylic silane ■), acyloxysilane I, vinyltriacequidisilane (hereinafter abbreviated as acyloxysilane ■), 1-hydroxy-1-methyl- Atomized silica (hereinafter abbreviated as silica I) as a reinforcing filler whose surface has been treated with ethyl phenyl ketone (hereinafter abbreviated as photopolymerization initiator ■) and hexamethyldisilazane and has a specific surface area of 130 m/g. Add in the amounts shown in Table 2 and mix uniformly to form a siloxane composition m~
(2) was prepared, and this composition was cured to form a rubber elastic body in the same manner as in Example 1, and the physical properties of this rubber and glass shear adhesive strength were investigated, and the results as listed in Table 2 were obtained. From this result, it was confirmed that the acrylic group-containing alkoxysilane as the second component and the acyloxysilane as the third component are essential components.

(Effects of the Invention) The present invention relates to a photo-effect organopolysiloxane composition and a cured product thereof, which comprises A) as described above.
Organopolysiloxane containing an acryloxyorganosilyl group, B) an acrylic alkoxysilane, C)
The present invention relates to a composition comprising an acyloxysilane and D) a photopolymerization initiator, and a cured product thereof, in which component A) contains an acryloxylorganosilyl group, and component B) Since the acrylic group-containing alkoxysilane as a component and the acyloxysilane as a component C) are added, it cures in a short time when exposed to ultraviolet rays, and the silicone rubber cured product obtained in this way can be used for glass, plastic, etc. This gives it the industrial advantage of being useful as adhesives, sealants, coatings, and potting agents.

[Brief explanation of the drawing]

FIG. 1 shows a plan view of a sample for glass shear adhesive force measurement used in Examples. Kaneji Arai =- Te6-Lee

Claims (1)

[Claims] 1, 1) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (Here, R^1 is a hydrogen atom or a methyl group, R^2, R
^3, R^4 are the same or different unsubstituted or substituted monovalent hydrocarbon groups, R^5 is an oxygen atom or a divalent hydrocarbon group,
a and b are 100 parts by weight of organopolysiloxane having at least one group represented by 1, 2 or 3) in the molecule; 2) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (here R^6 is the same or different unsubstituted or substituted 1
0.1 to 10 parts by weight of an alkoxysilane compound represented by a valent hydrocarbon group, R^7 is a divalent hydrocarbon group, R^8 is a hydrogen atom or a methyl group), 3) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (Here, R^9, R^1^0, R^1^1 are the same or different unsubstituted or substituted monovalent hydrocarbon groups, C is 1, 2
, 3 or 4, d is 0, 1, 2 or 3, C+d
is 1, 2, 3 or 4) 0.01 to 10 parts by weight of an acyloxysilane; 4) 0.01 to 10 parts by weight of a photopolymerization initiator. Organopolysiloxane composition. 2. A cured product obtained by curing the composition according to claim 1.