JPH0525907B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a photocurable organopolysiloxane composition, in particular a rubber-like composition which has excellent storage stability, cures by ultraviolet irradiation, and exhibits excellent adhesion to glass etc. The present invention relates to a photocurable organopolysiloxane composition that is useful as an adhesive, a sealant, a coating agent, and a potting agent because it is an elastic body. (Prior Art) It is well known that when organopolysiloxane is heated in the presence of an organic peroxide, it becomes a silicone rubber elastomer with excellent heat resistance, cold resistance, weather resistance, and electrical properties. However, some 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 by a photoradical addition reaction (especially (See Japanese Patent Publication No. 52-40334 and Japanese Patent Application Laid-Open No. 60-104158), but this has the disadvantage that its uses are limited due to problems with the odor of the mercapto group and the corrosivity of metals. Furthermore, as for compositions that harden by irradiation with light, compositions consisting of an acrylic group-containing polysiloxane and a sensitizer have been proposed (Japanese Patent Publication No. 53-36515, Japanese Patent Application Laid-Open No. 60-215009). However, in order to obtain a rubber-like elastic body, it is necessary to use a linear polymer with a high molecular weight, so the acrylic mass at the end is relatively very small, resulting in poor curability. However, due to the drawback that the surface area in contact with air hardly hardens due to the inhibition of hardening by oxygen, only resin-like materials with relatively large acrylic mass have been put into practical use, and there is no satisfactory rubber-like elastic material. has not been obtained. Therefore, the present inventors previously proposed a composition consisting of a polysiloxane in which multiple acrylic groups were introduced at the ends of a linear polymer and a sensitizer using a novel compound called acryloxyalkylsilanol (especially Although this product provides a practical silicone rubber elastic body, it does not adhere to glass or metal at all, making it unsuitable for various types of adhesive seals. I found out. (Structure of the Invention) The present invention relates to a photocurable organopolysiloxane composition that solves these disadvantages, and is composed of (1) general formula (Here, R ¹ is a hydrogen atom or a methyl group, R ² , R ³ ,
R ⁴ is an unsubstituted or substituted same or different monovalent hydrocarbon group, R ⁵ is an oxygen atom or a divalent hydrocarbon group, a is 1, 2 or 3, and b is 1, 2 or 3) 100 parts by weight of organopolysiloxane having at least one group in one molecule, (2) General formula [Here, R ⁶ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R ⁷ is the same or different divalent hydrocarbon group having 1 to 8 carbon atoms, and X is a hydrogen atom, unsubstituted or Substituted monovalent hydrocarbon group or formula (R ⁸ is a divalent hydrocarbon group having 1 to 8 carbon atoms; R ⁹ is a hydrogen atom or an unsubstituted or substituted 1 to 8 carbon group;
and (3) 0.01 to 10 parts by weight of a photoinitiator. be. That is, as a result of various studies aimed at developing a photocurable organopolysiloxane composition with particularly excellent adhesive properties and storage stability, the present inventors found that acryloxy as the first component represented by formula (1) When a small amount of an organosilicon compound as a second component represented by the above formula (2) is added to a composition consisting of an organopolysiloxane containing an organosilyl group and a photoinitiator as a third component, this composition completely cures in 1 to 10 seconds to become a rubber-like silicone elastic body, and the silicone elastic body thus obtained has strong adhesion to various substrates, and this composition has good storage stability. We confirmed that it has excellent viscosity and does not thicken even if left at 70℃ for 7 days.We conducted research on the types and amounts of each ingredient used and completed the present invention. . The organopolysiloxane as the first component constituting the composition of the present invention has a general formula in its molecule. , and this R ¹ is a hydrogen atom or a methyl group,
R ² , R ³ , R ⁴ are methyl group, ethyl group, propyl group,
Alkyl groups such as butyl groups, cycloalkyl groups such as cyclohexyl groups, alkenyl groups such as vinyl groups and aryl groups, aryl groups such as phenyl groups and tolyl groups, or some of the hydrogen atoms bonded to the carbon atoms of these groups. , or all halogen atoms,
the same or different unsubstituted or substituted monovalent hydrocarbon group selected from chloromethyl group substituted with cyano group, trifluoropropyl group, cyanoethyl group, etc., R ⁵ is an oxygen atom or a divalent hydrocarbon group, a is 1, 2 or 3, and b is 1, 2 or 3. This is a compound previously created by the present inventors. , Examples of this include the following: (n and m in the above formula are integers of 1 or more). Note that this organopolysiloxane can be obtained, for example, by the following method. In other words, this synthesis begins with the general formula (Here, R ¹⁰ is a divalent hydrocarbon group, R ¹¹ and R ¹² are unsubstituted or substituted monovalent hydrocarbon groups, and c is 0 or 1) Organosiloxane containing one or more groups, such as (d in the formula is 1, 2 or 3, e is 1 or 2,
n, m are integers of 1 or more) and an organopolysiloxane with the general formula and b is 1, 2 or 3, such as (CH ₃ ) ₂ HSiCl, CH ₃ HSiCl ₂ , HSiCl ₃
The general formula is An organopolysiloxane having the group shown at the end of the molecular chain, such as the following, is synthesized. Next, the general formula for this organopolysiloxane is , and R ¹ , R ² , R ³ , and a are as defined above, an acryloxyorganosilanol, e.g. is mixed in the organopolysiloxane described above so that the chloro group and the silanol group in this silanol are equimolar, and then reacted at room temperature in the presence of a dehydrochlorination agent such as triethylamine, and then desalted. Then, the desired organopolysiloxane as described above can be easily obtained. Next, the organosilicon compound as the second component constituting the composition of the present invention is expressed by the above formula (2). R ⁶ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms similar to R ² described above, preferably a methyl group, and R ⁷ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms as described above.
Divalent hydrocarbon group similar to R ⁵ , X is a hydrogen atom, unsubstituted or substituted monovalent hydrocarbon group or formula (Here, R ⁶ is a divalent hydrocarbon group having 1 to 8 carbon atoms,
R ⁹ is a group represented by a hydrogen atom or a monovalent hydrocarbon group having 1 to 8 carbon atoms similar to R ⁶ , and this is a group represented by the general formula (R ⁶ O) ₃ Si-R ⁷ A trialkoxysilane having an isocyanate group represented by -NCO- has the general formula It can be easily synthesized by mixing it with a hydroxyalkyl unsaturated ester represented by and reacting it in the presence of a condensation catalyst such as dibutyltin maleate. This organosilicon compound has _the formula ( _CH3O ) _{3Si ( CH2} ) _3NH2 , ( _CH3O ) _3Si ( _CH2 ) _3NH ( _CH2 ) _2NH2 ( _CH3O ) _3Si (CH ₂ ) ₃ NH (CH ₂ ) ₆ NH ₂ (CH ₃ O) ₃ Si (CH ₂ ) ₃ NHCH ₃ , (CH ₃ O) ₃ Si (CH ₂ ) ₃ NHCOCH=CH ₂ , (CH ₃ O) ₃ Si(CH ₂ ) ₃ NHCH ₂ CH=CH ₂ , Examples include. If the amount of this substance added is less than 0.01 part per 100 parts by weight of organophorisiloxane as the first component, the adhesive strength of the silicone rubber elastic body obtained from this composition will be weak, and if it is less than 10 parts, the adhesive strength of the silicone rubber elastic body obtained from this composition will be weak. This should be in the range of 0.01 to 10 parts by weight since curing will be adversely affected. Further, the photoinitiator as the third component in this composition is for promoting the photopolymerization of the acrylic group in the organopolysiloxane as the first component, which is well known in the art. These include acetophenone, propiophenone, benzophenone, xanthol, fluorein, benzaldehyde, anthraquinone, triphenylamine, carbazole,
-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, benzylmethoxyketanol, 2-chlorothioxanthone. diethoxyacetophenone,
1-hydroxycyclohexyl phenyl ketone,
2-Methyl-[4-(methylthio)phenyl]2-
Examples include morpholino-1-propanone and 2,2-dimethoxy-2-phenylacetophenone. This amount is based on 100 parts by weight of the organopolysiloxane as the first component mentioned above.
If it is less than 0.01 parts by weight, it will not have any 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, so it is necessary to keep it in the range of 0.01 to 10 parts by weight. There is. In the present invention, the composition can be obtained by uniformly mixing predetermined amounts of the first to third components described above. If necessary, a fumed silica filler that does not inhibit photocuring may be added, and furthermore, it is optional to add a thixotropy agent, a heat resistance improver, a coloring agent, etc. for the purpose of adjusting the physical properties. Ru. In the composition of the present invention thus obtained, since the organopolysiloxane as the first component contains a photopolymerizable acryloxyorganosilyl group, it can be easily irradiated with ultraviolet light in a short period of 1 to 20 seconds. The silicone rubber is cured into a silicone rubber, which is non-corrosive and odorless, and the addition of the second component makes this composition have good storage stability. Rubber elastic bodies adhere well to various base materials, so they can be used as potting materials, sealing materials, etc. for various electrical and electronic components.
It is said to be particularly useful as a coating material. Next, examples of synthesis of organopolysiloxane as the first component and examples of the present invention will be given.
In the examples, parts are parts by weight, and viscosity is a value measured at 25°C. Synthesis Example 1 A formula with a viscosity of 1000 cS is placed in the reaction flask from 2 equipped with a thermometer, condenser, and stirrer. Add 1000 g of α,ω-divinyldimethylpolysiloxane (vinyl value 0.018 mol/100 g) represented by the formula, heat it at 120°C for 2 hours under a nitrogen gas stream to dehydrate it, and after cooling, add isopropyl alcohol of chloroplatinic acid. Add 0.1 g of the solution (platinum content: 2% by weight) and 12.3 g of methyldichlorosilane and react at 90°C for 2 hours. At the same temperature, nitrogen gas is passed through the solution to remove unreacted methyldichlorosilane from the system. It was removed. Next, add 23.8g of triethylamine and 2.
6-di-t-butyl-4-methylphenol 0.4
After adding 17.2 g of α-acryloxymethyldimethylsilanol over 30 minutes, the mixture was heated at 60℃ for 2 hours.
After reacting for an hour, 500g of toluene was added, the salt produced was separated, and the strip was stripped at 100°C/2mmHg to remove toluene and excess triethylamine under reduced pressure, resulting in a viscosity of 3400cS.
the formula of 920 g of a colorless and transparent organopolysiloxane (hereinafter abbreviated as polysiloxane) was obtained. Synthesis Example 2 A formula with a viscosity of 3400 cS was placed in the reaction flask 2 equipped with a thermometer, condenser, and stirrer. Add 1000 g of α,ω-divinyldimethylphenylpolysiloxane (vinyl value 0.018 mol/100 g, phenyl group content 30 mol%) shown by the formula, heat it at 120°C for 2 hours under a nitrogen gas stream to dehydrate it, and after cooling. Here, 0.1 g of isopropyl alcohol solution of chloroplatinic acid (platinum amount: 2% by weight) and methyldichlorosilane
After adding 12.2 g of the solution and reacting at 50° C. for 1 hour and then at 80° C. for 3 hours, unreacted methyldiglorosilane was removed from the system by flowing nitrogen gas into the solution at the same temperature. Next, add 21.5 g of triethylamine and 2,
6-di-t-butyl-4-metholphenome 0.4
After adding 34.1 g of α-acryloxymethyldimethylsilanol over 30 minutes,
Separate the salt produced after reacting for 100 hrs.
When the excess triethylamine was removed under reduced pressure by stripping under the conditions of ℃/2 mmHg, the following formula was obtained. 900 g of a colorless and transparent organopolysiloxane (hereinafter abbreviated as polysiloxane) was obtained. Synthesis Example 3 The α,ω-divinyldimethyldiphenylpolysiloxane in the above synthesis example is Processed in the same manner as in Synthesis Example 1, except that the amount of methyldichlorosilane added was 33.8g, the amount of triethylamine added was 59.4g, and the amount of α-acryloxymethyldimethylsilanol was changed to 94.1g. As a result, the following colorless and transparent formula 880 g of organopolysiloxane (hereinafter abbreviated as polysiloxane) represented by the formula was obtained. Example 1, Comparative Example 1 Polysiloxane obtained in Synthesis Example 1 described above
To 100 parts, 0.5 part of γ-aminopropyltrimethoxysilane (hereinafter abbreviated as aminosilane) and 1.0 part of 1-hydroxycyclohexyl phenyl ketone (hereinafter abbreviated as photoinitiator) were added and mixed uniformly to form a siloxane composition. In addition, for comparison, a siloxane composition was prepared in the above manner without the addition of aminosilane. Then this siloxane composition, from 120×
A sheet of 120 x 2 mm was formed, and it was cured by irradiating it with ultraviolet light three times at a speed of 1 m/min using an ultraviolet irradiation device ASE-20 (trade name manufactured by Nippon Battery Co., Ltd.). JISK-6301 physical properties of rubber elastic bodies
(Vulcanized Rubber Physical Test Method), a sample for glass shear adhesion measurement as shown in Figure 1 was made from this composition, and it was irradiated with ultraviolet rays from the above-mentioned ultraviolet irradiation device. When the glass shear adhesive strength was measured 24 hours after curing, the results shown in Table 1 were obtained.

[Table] Examples 2 to 4, Comparative Examples 2 to 4 Polysiloxane 100 obtained in Synthesis Example 2 described above
0.5 part of the aminosilane used in Example 1, 2.0 parts of the photoinitiator, and fumed silica (hereinafter abbreviated as silica) as a reinforcing filler with a specific surface area of 200 m ² /g hydrophobized with hexamethyldisilazane. ) was added in the amount shown in Table 2 and kneaded uniformly to prepare the siloxane composition ~, and for comparison, the same procedure as above was performed except that the aminosilane was not added to create the siloxane composition ~. The siloxane composition ~ was treated in the same manner as in Example 1, and the physical properties and glass shear adhesive strength of the rubber elastic body obtained were examined, and the results are shown in Table 2. Ta.

[Table] Examples 5 to 8, Comparative Example 5 N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (hereinafter abbreviated as aminosilane) was added to 100 parts of the polysiloxane obtained in Synthesis Examples 1 to 3 above. ), N-[N-(β-aminoethyl)
-β-Aminoethyl]-γ-aminopropyltrimethoxysilane (hereinafter abbreviated as aminosilane) or N-allyl-γ-aminopropyltrimethoxysilane (hereinafter abbreviated as aminosilane) and the photoinitiator used in Example 1 or 1-
The specific surface area after hydrophobizing with hydroxy-1-methyl-ethyl phenyl ketone (hereinafter abbreviated as photoinitiator) and dimethyldichlorosilane is 200 m ² /g.
Atomized silica (hereinafter abbreviated as silica) as a reinforcing filler was blended in the amount shown in Table 3 and mixed uniformly to prepare siloxane composition ~XII. 2.0 parts of a photoinitiator was blended and mixed uniformly to prepare a siloxane composition, and these compositions were treated in the same manner as in Example 1 to determine the physical properties and glass shear adhesion of the rubber elastic body obtained from them. When we investigated the results, we obtained the results shown in Table 3.

[Table] Example 9, Comparative Example 6 Polysiloxane obtained in Synthesis Example 1 above
100 copies, formula 1 part of an organosilicon silicon compound (hereinafter abbreviated as acryloxysilane) shown by and Example 5,
Add 2 parts of the photoinitiator used in 7 and 8;
In addition to uniformly mixing the siloxane composition, the acryloxysilane described above was used for comparison.
A siloxane composition was prepared in the same manner as above, except that . Next, a sheet of 120 x 120 x 2 mm was formed from this composition, and this was exposed to an 80 W/cm ultraviolet irradiation device.
UD-20-2 [trade name manufactured by Nippon Battery Co., Ltd.] When irradiated with ultraviolet light using two lamps, it completely cured into a silicone rubber elastic body in 1 to 4 seconds, so this physical property was measured in accordance with JIS K-6301 (mentioned above), and a sample for glass shear adhesion measurement was made from this composition, and was cured by irradiation with ultraviolet rays in the same manner as above, and then cured for 24 hours. When the adhesive strength was measured afterwards, the results shown in Table 4 were obtained.

[Table] Examples 10 to 12, Comparative Examples 7 to 9 To 100 parts of the polysiloxane obtained in Synthesis Examples 2 and 3 above, the acryloxysilane used in Example 9, a photoinitiator, and a reinforcing filler were added. Silica as an agent was added in the amount shown in Table 5 and mixed uniformly to prepare the composition, and for comparison, the same process as above was carried out except that acryloxysilane was not added. Composition ~XI was made. Next, this composition - .

[Table] Examples 13 to 16 Polysiloxanes obtained in Synthesis Example 2 above
100 copies, formula An organosilicon compound (hereinafter abbreviated as acryloxysilane) represented by the formula An organosilicon compound (hereinafter abbreviated as acryloxysilane) represented by the formula A ratio of an organosilicon compound (hereinafter abbreviated as acryloxysilane) or γ-aminopropyltrimethoxysilane (aminosilane) shown in the formula, hydrophobized with a photoinitiator and hexamethyldisilazane as a reinforcing filler. surface area is 300
^Compositions The viscosity did not increase even after several days, and these
When the rubber physical properties and glass shear adhesive strength of the obtained silicone gel elastomer were measured in the same manner as above, the results shown in Table 6 were obtained.

【table】 [Brief explanation of the drawing]

FIG. 1 shows the shape and dimensions of a test piece for measuring the glass shear adhesion of a silicone rubber elastic body.

Claims (1)

[Claims] 1 (1) General formula (Here, R ¹ is a hydrogen atom or a methyl group, R ² is
R ³ and 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 is 1, 2 or 3, and b is 1 or 2
or 100 parts by weight of an organopolysiloxane having at least one group represented by 3) in the molecule, (2) General formula [Here, R ⁶ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R ⁷ is the same or different divalent hydrocarbon group having 1 to 8 carbon atoms, X is a hydrogen atom,
unsubstituted or substituted monovalent hydrocarbon group or formula (R ⁸ is a divalent hydrocarbon group having 1 to 8 carbon atoms, R ⁹ is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms) Compound or its partial hydrolyzate
0.01 to 10 parts by weight; (3) 0.01 to 10 parts by weight of a photoinitiator. 2 (2) Component is general formula (R ⁶ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R ⁷ and R ⁸ are the same or different divalent hydrocarbon groups having 1 to 8 carbon atoms, and R ⁹ is a hydrogen atom. or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms) or a partial hydrolyzate thereof. 3 (2) Component is a general formula The photocurable organopolysiloxane composition according to claim 1, which is an organosilicon compound represented by (wherein Z is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group).