JPH10324806A - Curable organopolysiloxane composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition which quickly thickens at ordinary temperature, cures with moisture forming an elastomer by selecting a composition comprising a plurality of organopolysiloxanes having specified compositions, a branched siloxane/silalkylene copolymer and a plurality of catalysts and having a specified viscosity. SOLUTION: This composition comprises an organopolysiloxane represented by the average unit formula: R<1> a SiO(4-a)/2 (at least 80 mol% of R<1> s are monovalent hydrocarbon groups or alkoxyls, provided that at least 2 mol% of the hydrocarbon groups are alkenyls; and a is 0.75-2.5) and having trifunctional units of the formula: R<1> SiO3/2 or tetrafunctional units of the formula: SiO4/2 in the molecule, an alkenyl-free organopolysiloxane having at least three Si- bonded alkoxyls, an Si-bonded-H-containing branched siloxane/silalkylene copolymer of the formula, a condensation reaction promoting catalyst and an addition reaction promoting catalyst and having a viscosity of 30,000 P or below. In the formulas, R<2> is a 1-10C alkyl or an aryl; b is 3 or 4; and X<1> is a specified silylalkyl.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to curable organopolysiloxane compositions. More specifically, the present invention relates to a curable organopolysiloxane composition suitable for use as an adhesive, which can rapidly increase in viscosity at room temperature, and thereafter, the curing reaction can further proceed due to moisture in the atmosphere to become an elastic body.

[0002]

2. Description of the Related Art A moisture-curable organopolysiloxane composition that can be stored for a long time in the absence of moisture and cures at room temperature in the presence of moisture has a cured product having excellent heat resistance, electrical properties, and weather resistance. Therefore, it is used as an adhesive, a potting material, a coating material and the like. However, such a moisture-curable organopolysiloxane composition has a problem that curing is slow when used in a thick film, and that curing of a substrate gap is slow when used as an adhesive. For this reason, dual-curable silicone rubber compositions have been proposed in which an addition reaction between an alkenyl group and a silicon-bonded hydrogen atom is combined with a moisture curing reaction (Japanese Patent Publication No. 64-2626 and Japanese Patent Application Laid-Open No. 7-207164). reference). However, even with this dual-curable composition, when it was used as an adhesive, at least 5 minutes of standing was required to obtain sufficient adhesiveness to eliminate the need for fixing means. To solve this, it is possible to increase the curing rate by increasing the amount of the catalyst, but as a result, the preparation of the composition becomes difficult, and gelation occurs before bonding the substrate. There was a problem that a sufficient adhesive strength could not be obtained due to the occurrence.

[0003]

The inventors of the present invention have made intensive studies to solve the above problems, and as a result, have reached the present invention.
That is, the object of the present invention is to increase the viscosity quickly at room temperature,
Thereafter, it is an object of the present invention to provide a curable organopolysiloxane composition which can be further turned into an elastic body by a curing reaction further proceeding due to moisture in the atmosphere.

[0004]

The present invention provides (A) and (a)
Average unit formula: R ¹ _a SiO _{(4-a) / 2} (wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group or alkoxy group, and at least 80 mol% of R ¹ is substituted or unsubstituted) Is a substituted monovalent hydrocarbon group, and at least 2 mol% of the monovalent hydrocarbon group is an alkenyl group, and a is a number of 0.75 to 2.5). Formula:
A trifunctional unit represented by R ¹ SiO _3/2 (wherein R ¹ is the same as described above) or _{4 represented} by the formula: SiO _4/2
Organopolysiloxanes containing functional units
(B) an organopolysiloxane having a viscosity of 1 to 1,000 poise at 25 ° C. and containing at least three silicon-bonded alkoxy groups per molecule (provided that the organopolysiloxane is alkenyl Containing no groups.) 60 to 40% by weight,
(B) General formula:

Embedded image Wherein R ² is an alkyl or aryl group having 1 to 10 carbon atoms, b is 3 or 4, and X ¹ is i
= 1, which is a silylalkyl group represented by the following formula.

Embedded image (Wherein, R ² is the same as above, and R ³ has 2 to 2 carbon atoms.
10 alkylene groups, and R ⁴ has 1 to 10 carbon atoms.
Is an alkyl group. X ^{i + 1} is a hydrogen atom or the above silylalkyl group, while X ^{i + 1} located at the terminal of the molecular chain is a hydrogen atom. i is an integer of from 1 to 10, which shows the hierarchy of the silylalkyl group, c ⁱ is an integer of 0 to 3, the average total number of c ⁱ in one molecule or less 1.5 ⁱ × b is there. ) The number of moles of silicon-bonded hydrogen atoms per mole of alkenyl groups in the branched siloxane / silalkylene copolymer (A) component containing silicon-bonded hydrogen atoms represented by｝ is from 0.3 to 3. Amount to be 0 (C) Condensation reaction accelerating catalyst Catalyst amount and (D) Addition reaction accelerating catalyst
The present invention relates to a curable organopolysiloxane composition comprising a catalyst and having a viscosity at 25 ° C of 30,000 poise or less.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION (A) used in the composition of the present invention
The component is a mixture comprising (a) 40 to 60% by weight of an alkenyl group-containing organopolysiloxane and (b) 60 to 40% by weight of an alkoxy group-containing organopolysiloxane. The organopolysiloxane of the component (a) constituting the component (A) is a component necessary for achieving an initial rapid viscosity increase, and has an average unit formula: R ¹ _a
A trifunctional unit (T unit) represented by SiO _{(4- a) / 2} and having a formula: R ¹ SiO _3/2 in the molecule or a formula: SiO _4/2
And a tetrafunctional unit (Q unit) represented by In the above formula, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group or an alkoxy group, of which at least 80 mol% is a substituted or unsubstituted monovalent hydrocarbon group. Specific examples of the monovalent hydrocarbon group include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, isopropyl group, isobutyl group, cyclopentyl group and cyclohexyl group; vinyl group, allyl group, hexenyl group Alkenyl groups such as phenyl group and naphthyl group; aralkyl groups such as benzyl group and 1-phenylethyl group; chloromethyl group, 3-chloropropyl group, 3,3,
Halogenated alkyl groups such as 3-trifluoropropyl group and nonafluorobutylethyl group; halogenated aryl groups such as 4-chlorophenyl group, 3,5-dichlorophenyl group and 3,5-difluorophenyl group; 4-chloromethylphenyl And a halogenated alkyl group-substituted aryl group such as a 4-trifluoromethylphenyl group.
Further, at least 2 mol% of the monovalent hydrocarbon group must be an alkenyl group, preferably 2 to 1 mol%.
The range is 0 mol%. The alkenyl group is preferably a vinyl group, and the monovalent hydrocarbon group other than the alkenyl group is preferably a methyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and an isopropoxy group. Among them, a methoxy group or an ethoxy group is preferable. a is a number from 0.75 to 2.5. Such this component, wherein: R ¹ ₃ SiO _1/2
(Wherein R ¹ is the same as described above), an organopolysiloxane (MQ resin) comprising a monofunctional unit (M unit) and a Q unit, and an organopolysiloxane comprising an M unit, a T unit and a Q unit. siloxane (MTQ resin), M units of the formula: R ¹ ₂ SiO _2/2 (wherein, R ¹ is as defined above.)
, An organopolysiloxane (MDQ resin) consisting of a bifunctional unit (D unit) and a Q unit, an organopolysiloxane (MDTQ resin) consisting of an M unit, a D unit, a T unit and a Q unit, consisting of only a T unit Organopolysiloxane (T resin) is exemplified. Preferably, the average composition _{^{formula: (R 5 3 SiO 1/2)}} d (SiO 4/2) organopolysiloxane or the average composition formula represented by _e: (R ⁵ ₃ S
iO _1/2 ) _f (R ⁵ SiO _3/2 ) _g (SiO _4/2 ) _h (R ⁶ O
_1/2 ) An organopolysiloxane represented by _j . In the above formulas, R ⁵ is a substituted or unsubstituted monovalent hydrocarbon radical containing at least 2 mol% of alkenyl groups, in particular R ¹
The same thing as the monovalent hydrocarbon group in it is mentioned. R ⁶ is an alkyl group, such as a methyl group, an ethyl group, or a propyl group. d / e and f / h are in the range of 0.2 to 1.5, preferably in the range of 0.5 to 1.2. g / h
Is 0.05 to 0.2 and j / h is 0.05 to 0.6. The alkoxy group represented by the formula (R ⁶ O _1/2 ) is bonded to a silicon atom. The organopolysiloxane of this component has a number average molecular weight of 1,000 to 10,000.
And more preferably 3,000.
In the range of ６6,000.

Examples of the organopolysiloxane of the component (a) include compounds represented by the following formula. ｛(CH ₃ ) ₃ SiO _1/2 ｝ ₃₆ ｛CH ₂ ＣＨCH (CH ₃ ) ₂ SiO
_1/2 ｝ ₅ (SiO _4/2 ) ₅₉ ｛(CH ₃ ) ₃ SiO _1/2 ｝ ₄₀ ｛CH ₂ ＣＨCH (CH ₃ ) ₂ SiO
_1/2 ｝ ₅ (SiO _4/2 ) ₅₅ ｛(CH ₃ ) ₃ SiO _1/2 ｝ ₃₆ ｛CH ₂ ＣＨCH (CH ₃ ) ₂ SiO
_1/2 ｝ ₅ (CH ₃ SiO _3/2 ) ₅ (SiO _4/2 ) ₅₉ ｛(CH ₃ ) ₃ SiO _1/2 ｝ ₄₀ ｛CH ₂ ＣＨCH (CH ₃ ) ₂ SiO
_1/2 ｝ ₇ (SiO _4/2 ) ₆₀ (CH ₃ O _1/2 ) ₁₀ ｛(CH ₃ ) ₃ SiO _1/2 ｝ ₃₆ ｛CH ₂ ＣＨCH (CH ₃ ) ₂ SiO
_1/2 ｝ ₅ (CH ₃ SiO _3/2 ) ₅ (SiO _4/2 ) ₅₉ (CH ₃ O
_1/2 ) ₁₅ ｛(CH ₃ ) ₃ SiO _1/2 ｝ ₃₅ ｛CH ₂ ＣＨCH (CH ₃ ) ₂ SiO
_1/2 ｝ ₅ (SiO _4/2 ) ₆₀ (CH ₃ O _1/2 ) ₁₀

The organopolysiloxane of component (b), which is another component of component (A), is a component that causes crosslinking by the action of moisture and contains at least three silicon-bonded alkoxy groups per molecule. I do. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group,
A butoxy group and an isopropoxy group are exemplified, and among them, a methoxy group or an ethoxy group is preferable. The viscosity of this component at 25 ° C. is in the range of 1 to 1,000 poise, preferably in the range of 10 to 800 poise. When the viscosity is less than 1 poise, the viscosity of the composition of the present invention becomes too low and the tackiness may decrease. This is because workability and coating workability are reduced. As the group bonded to a silicon atom other than the alkoxy group, a substituted or unsubstituted monovalent hydrocarbon group other than an alkenyl group is preferable, and specifically, a methyl group, an ethyl group, a propyl group, a butyl group, Alkyl groups such as pentyl group, isopropyl group, isobutyl group, cyclopentyl group and cyclohexyl group; aryl groups such as phenyl group and naphthyl group; aralkyl groups such as benzyl group and 1-phenylethyl group;
Halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group and nonafluorobutylethyl group; 4-chlorophenyl group;
Examples thereof include a halogenated aryl group such as a 3,5-dichlorophenyl group and a 3,5-difluorophenyl group; and a halogenated alkyl group-substituted aryl group such as a 4-chloromethylphenyl group and a 4-trifluoromethylphenyl group. Among these, a methyl group is preferred. The molecular structure of the organopolysiloxane of the present component is preferably linear, but may have some branches.

Examples of the organopolysiloxane of the component (b) include compounds represented by the following formula.

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The branched siloxane / silalkylene copolymer of the component (B) used in the composition of the present invention is a component necessary for achieving an initial and rapid increase in viscosity. Because it contains
The component (D) reacts with an alkenyl group in the component (a) by the action of an addition reaction promoting catalyst. This component has the general formula:

Embedded image Indicated by In the above formula, R ² is an alkyl group or an aryl group having 1 to 10 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, an isopropyl group, an isobutyl group and a cyclopentyl group. , Cyclohexyl group and phenyl group and naphthyl group as aryl group. Among these, a methyl group is preferred. b is 3 or 4, and X ¹
Is a silylalkyl group represented by the following formula when i = 1.

Embedded image In the above formula, R ³ is an alkylene group having 2 to 10 carbon atoms, and a linear alkylene group such as ethylene group, propylene group, butylene group, hexylene group; methylmethylene group, methylethylene group, 1-methylpentene Examples thereof include a branched alkylene group such as a len group and a 1,4-dimethylbutylene group. Among them, an ethylene group, a methylmethylene group, a hexylene group, a 1-methylpentylene group, and a 1,4-dimethylbutylene group are preferred. R ⁴ is an alkyl group having 1 to 10 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and an isopropyl group. Among these, a methyl group or an ethyl group is preferable. X
^{i + 1} is a hydrogen atom or the above silylalkyl group,
X ^{i + 1} located at the terminal of the molecular chain is a hydrogen atom. i is 1
Is an integer of 10 to 10, which indicates the number of levels of the silylalkyl group, that is, the number of repetitions of the silylalkyl group. Therefore, when the number of layers is 1, the branched siloxane / silalkylene copolymer of this component has the general formula:

Embedded image In the case where the number of layers is 2 and the branched siloxane / silalkylene copolymer of this component is represented by the general formula:

Embedded image In the case where the number of ranks is 3 and the branched siloxane / silalkylene copolymer of this component is represented by the general formula:

Embedded image Indicated by C ⁱ is an integer of 0 to 3, and the average total number of c ^{i in} one molecule is 1.5 ⁱ × b or less. Note that c ⁱ
Is not 0, that is, when an alkoxy group is present in the component, the component contributes to crosslinking by the action of moisture similarly to the organopolysiloxane of the component (b). The amount of this component is the amount of alkenyl group 1 in component (A).
The amount is such that the number of moles of silicon-bonded hydrogen atoms in this component is from 0.3 to 3.0, and preferably from 0.5 to 3.0.
It is an amount that becomes .about.2.0.

Examples of the branched siloxane / silalkylene copolymer of the component (B) include polymers represented by the following average composition formula.

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The catalyst for promoting the condensation reaction of the component (C) used in the composition of the present invention is a component for promoting the hydrolysis and condensation reaction of the alkoxy groups in the components (A) and (B). As this component, a conventionally known condensation reaction accelerating catalyst can be used, and a tetraalkoxytitanium compound such as tetraisopropoxytitanium or tetrabutoxytitanium; diisopropoxybis (ethyl acetoacetate) titanium, diisopropoxybis (acetylacetone) titanium, Titanium complex compounds such as dibutoxybis (methyl acetoacetate) titanium;
Examples thereof include dialkyltin carboxylate compounds such as dibutyltin diacetate, dibutyltin dioctoate, and dibutyltin dilaurate; and tin carboxylate compounds such as stannas octoate. Among these, a tetraalkoxy titanium compound or a titanium complex compound is preferable. The amount of this component used is a catalytic amount, but (A)
0.01 with respect to 100 parts by weight of the total of the component and the component (B)
It is preferably in the range of 10 to 10 parts by weight.

The catalyst for accelerating the addition reaction of component (D) used in the composition of the present invention is a catalyst for the addition reaction between the alkenyl group in component (a) and the silicon-bonded hydrogen atom in component (B). It is. This component includes a platinum compound,
Rhodium compounds, palladium compounds, ruthenium,
Compounds such as iridium, iron, cobalt, manganese, zinc, lead, aluminum, nickel and the like can be mentioned. Of these, platinum compounds are preferred, and specific examples thereof include chloroplatinic acid, alcohol-modified platinum chloride, a reaction product of chloroplatinic acid with an olefin or vinyl siloxane, and a platinum-supported carrier such as alumina or silica. Is done. The amount of this component depends on the type and is a catalytic amount,
When a platinum compound is used as this component,
It is preferable that the amount is such that the platinum atomic weight is in the range of 0.000001 to 0.01 parts by weight based on 100 parts by weight of the total of the components (A) and (B).

The composition of the present invention comprises the above components (A) to (D). If necessary, a storage stabilizer such as alkoxysilane, a filler such as fumed silica, etc.
A functional or non-functional organopolysiloxane gum, a plasticizer, a thixotropy-imparting agent, a heat-resistant additive, a coloring agent, an adhesion-imparting agent and the like can be added and compounded.

The viscosity of the composition of the present invention at 25 ° C. is 3
Less than 0000 poise, preferably 100 to 20,
000 poise. This is because if it exceeds 30,000 poise, it becomes difficult to apply it to various substrates.

The composition of the present invention can be produced by uniformly mixing the above components (A) to (D). However, the reaction starts simultaneously with the mixing to increase the viscosity, so that it is necessary to mix the components promptly. . For that purpose, for example, the component (A)
Mix the components (C) uniformly beforehand, add the components (D) immediately before use and mix them quickly.
A mixture comprising the components (A) and (B);
It is preferable to prepare a mixture comprising the component, the component (C) and the component (D) so as to have equal viscosities, and to mix and use these at a predetermined ratio quickly.

The curable organopolysiloxane composition of the present invention as described above rapidly thickens at room temperature and then undergoes a cross-linking reaction due to the action of atmospheric moisture to become an elastic body. Is good and the final adhesiveness is high. For this reason, the composition of the present invention is suitably used as an adhesive.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. In the examples, the viscosity is a value measured at 25 ° C.
The tensile shear adhesive strength of the curable organopolysiloxane composition was measured according to the following method.

○ Tensile shear adhesive strength The curable organopolysiloxane composition immediately after preparation was uniformly applied to an aluminum test panel having a thickness of 1 mm and a width of 2.5 cm so as to have a thickness of about 0.2 mm. .
After standing for 1 minute, the same aluminum test panel as described above was bonded to the coated surface so that the bonding area was 2.5 cm ² . Then, for a certain period of time (5 minutes, 30 minutes, 1
After 4 hours, 1 day, 5 days), the tensile shear adhesive strength (kg / cm ² ) was measured according to the method specified in JIS K6850. The state of destruction of the cured product after the measurement after 5 days was visually observed.

[0019]

Reference Example 1 103.6 g of vinyltrimethoxysilane and 0.04 g of a 3% solution of chloroplatinic acid in isopropanol were charged into a 200 ml four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a dropping funnel. Heat to 100 ° C. with stirring. Next, 49.4 g of tetrakis (dimethylsiloxy) silane was slowly added dropwise thereto using a dropping funnel so that the reaction temperature was maintained at 100 to 110 ° C. After the addition was completed, the reaction solution was heated at 120 ° C. for 1 hour. After cooling, the reaction solution was transferred to a mold flask and concentrated under reduced pressure by a rotary evaporator to obtain 138.4 g of a slightly brown liquid. Subsequently, 141.0 g of 1,1,3,3-tetramethyldisiloxane, 100 ml of concentrated hydrochloric acid, 200 ml of water and 200 ml of isopropanol were placed in a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a dropping funnel. 200 ml were charged and stirred. Next, 80.6 g of the slightly brown liquid obtained above was slowly dropped over 1 hour using a dropping funnel. After the addition was completed, the reaction solution was stirred at room temperature for 1 hour. Next, the reaction solution was transferred to a separating funnel to separate the lower layer, and the remaining upper layer solution was washed twice with 200 ml of water and once with 50 ml of a saturated aqueous solution of sodium hydrogen carbonate, and dried over anhydrous magnesium sulfate. The generated solid was filtered off, transferred to a mold flask containing the obtained solution, and concentrated under reduced pressure by a rotary evaporator to obtain a branched siloxane / silalkylene copolymer represented by the following average composition formula.

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[0020]

[Reference Example 2] In a 1-liter four-necked flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel, 1,1,
134.3 g of 3,3-tetramethyldisiloxane, 100 ml of concentrated hydrochloric acid, 200 ml of water and isopropanol 20
0 ml was added and stirred. This is then followed by the average composition formula:

Embedded image Was dropped slowly over 1 hour using a dropping funnel. After the addition was completed, the reaction solution was stirred at room temperature for 1 hour. Next, the reaction solution was transferred to a separating funnel to separate the lower layer, and the remaining upper layer solution was washed twice with 200 ml of water and once with 50 ml of a saturated aqueous solution of sodium hydrogen carbonate, and dried over anhydrous magnesium sulfate. The generated solid was filtered off, transferred to a mold flask containing the obtained solution, and concentrated under reduced pressure by a rotary evaporator to obtain a branched siloxane / silalkylene copolymer represented by the following average composition formula.

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[0021]

Embodiment 1 Formula: {(CH ₃ ) ₃ SiO _1/2 } ₃₆ ｛CH ₂ ＣC
H (CH ₃ ) ₂ SiO _1/2 ｝ ₅ (CH ₃ SiO _3/2 ) ₅ (SiO
25.5 g of a 77.3% by weight xylene solution of an organopolysiloxane represented by _4/2 ) ₅₉ (CH ₃ O _1/2 ) ₁₅ and having a number average molecular weight in terms of polystyrene of 3,100;
formula:

Embedded image Was uniformly mixed with 26.6 g of a methoxy group-containing dimethylpolysiloxane having a viscosity of 20 poise and then heated under reduced pressure to remove xylene (weight mixing ratio: 40: 6).
0). After cooling, the average composition formula obtained in Reference Example 1:

Embedded image 2.1 g of a branched siloxane / silalkylene copolymer represented by the following formula (an amount in which the number of moles of silicon-bonded hydrogen atoms is 1.0 with respect to 1 mole of the alkenyl group in the organopolysiloxane), diisopropoxydiamine 0.5 g (1% by weight) of titanium (ethyl acetylacetonate) and 1.5 g of methyltrimethoxysilane were blended and uniformly mixed in a dry atmosphere to obtain a reaction mixture having a viscosity of 120 poise. Then, a toluene solution of a platinum divinyltetramethyldisiloxane complex having a platinum concentration of 0.5% was added to this in an amount of 0.3%.
g (atomic weight of platinum 0.003% by weight) was added and mixed quickly to prepare a curable organopolysiloxane composition. Tensile shear adhesive strength of the obtained curable organopolysiloxane composition was measured. The results are shown in Table 1.

[0022]

Embodiment 2 Formula: {(CH ₃ ) ₃ SiO _1/2 ｝ ₄₀ } CH ₂ ＣC
_{H (CH 3) 2 SiO 1/2} } 5 indicated by _{(SiO 4/2) 55,} 70 wt% xylene solution 3 organopolysiloxane number average molecular weight terms of polystyrene is 3,200
1.6 g and the formula:

Embedded image Was uniformly mixed with 22.1 g of a methoxy group-containing dimethylpolysiloxane having a viscosity of 130 poise, and then heated under reduced pressure to remove xylene (weight mixing ratio: 50: 5).
0). After cooling, the average composition formula obtained in Reference Example 2 was:

Embedded image 1.7 g of a branched siloxane / silalkylene copolymer represented by the following formula (the amount of moles of silicon-bonded hydrogen atoms to 0.6 with respect to 1 mole of alkenyl groups in the organopolysiloxane) and tetrabutoxytitanium 0 .5g
(1% by weight) and uniformly mixed in a dry atmosphere to obtain a reaction mixture having a viscosity of 160 poise. Next, 0.3 g of a toluene solution of a platinum divinyltetramethyldisiloxane complex having a platinum concentration of 0.5% (a platinum atomic weight of 0.3%) was added thereto.
003% by weight) and mixed quickly to prepare a curable organopolysiloxane composition. Tensile shear adhesive strength of the obtained curable organopolysiloxane composition was measured. The results are shown in Table 1.

[0023]

Comparative Example 1 Formula: {(CH ₃ ) ₃ SiO _1/2 } ₃₆ ｛CH ₂ ＣC
H (CH ₃ ) ₂ SiO _1/2 ｝ ₅ (CH ₃ SiO _3/2 ) ₅ (SiO
19.0 g of a 77.3% by weight xylene solution of an organopolysiloxane represented by _4/2 ) ₅₉ (CH ₃ O _1/2 ) ₁₅ and having a number average molecular weight in terms of polystyrene of 3,100;
formula:

Embedded image Was uniformly mixed with 32.0 g of a methoxy group-containing dimethylpolysiloxane having a viscosity of 20 poise and then heated under reduced pressure to remove xylene (weight mixing ratio: 30: 7).
0). After cooling, the average composition formula obtained in Reference Example 1:

Embedded image 1.8 g of a branched siloxane / silalkylene copolymer represented by the following formula (an amount in which the number of moles of silicon-bonded hydrogen atoms is 1.0 with respect to 1 mole of alkenyl groups in the organopolysiloxane), diisopropoxydiamine 0.5 g (1% by weight) of titanium (ethyl acetylacetonate) and 1.5 g of methyltrimethoxysilane were blended and uniformly mixed in a dry atmosphere to obtain a reaction mixture having a viscosity of 60 poise. Then, 0.3 g of a toluene solution of a platinum divinyltetramethyldisiloxane complex having a platinum concentration of 0.5% was added thereto.
(A platinum atomic weight of 0.003% by weight) was added and mixed quickly to prepare a curable organopolysiloxane composition.
Tensile shear adhesive strength of the obtained curable organopolysiloxane composition was measured. The results are shown in Table 1.

[0024]

Comparative Example 2 Formula: {(CH ₃ ) ₃ SiO _1/2 } ₃₆ ｛CH ₂ ＣC
H (CH ₃ ) ₂ SiO _1/2 ｝ ₅ (CH ₃ SiO _3/2 ) ₅ (SiO
19.0 g of a 77.3% by weight xylene solution of an organopolysiloxane represented by _4/2 ) ₅₉ (CH ₃ O _1/2 ) ₁₅ and having a number average molecular weight in terms of polystyrene of 3,100;
formula:

Embedded image Was uniformly mixed with 32.0 g of a methoxy group-containing dimethylpolysiloxane having a viscosity of 20 poise and then heated under reduced pressure to remove xylene (weight mixing ratio: 7).
0:30), and solidified, making it impossible to mix other components.

[0025]

Comparative Example 3 Formula: {(CH ₃ ) ₃ SiO _1/2 ｝ ₄₀ } CH ₂ ＣC
_{H (CH 3) 2 SiO 1/2} } 5 indicated by _{(SiO 4/2) 55,} 70 wt% xylene solution 3 organopolysiloxane number average molecular weight terms of polystyrene is 3,200
1.6 g and the formula:

Embedded image Was uniformly mixed with 22.1 g of a methoxy group-containing dimethylpolysiloxane having a viscosity of 130 poise, and then heated under reduced pressure to remove xylene (weight mixing ratio: 50: 5).
0). After cooling this, the formula:

Embedded image 0.8 of methyl hydrogen polysiloxane represented by
g (an amount in which the number of moles of silicon-bonded hydrogen atoms is 0.6 with respect to 1 mole of the alkenyl group in the organopolysiloxane) and 0.5 g (1% by weight) of tetrabutoxytitanium. And mix uniformly to obtain a viscosity of 1.
A 50 poise reaction mixture was obtained. Next, 0.3 g (a platinum atomic weight of 0.003% by weight) of a toluene solution of a platinum divinyltetramethyldisiloxane complex having a platinum concentration of 0.5% was added thereto, and the mixture was quickly mixed to obtain a curable organopolysiloxane composition. Prepared. Tensile shear adhesive strength of the obtained curable organopolysiloxane composition was measured. The results are shown in Table 1.

[0026]

Comparative Example 4 Formula: {(CH ₃ ) ₃ SiO _1/2 ｝ ₄₀ } CH ₂ ｛C
_{H (CH 3) 2 SiO 1/2} } 5 indicated by _{(SiO 4/2) 55,} 70 wt% xylene solution 3 organopolysiloxane number average molecular weight terms of polystyrene is 3,200
1.6 g and the formula:

Embedded image Was uniformly mixed with 22.1 g of a methoxy group-containing dimethylpolysiloxane having a viscosity of 130 poise, and then heated under reduced pressure to remove xylene (weight mixing ratio: 50: 5).
0). After cooling, the average composition formula obtained in Reference Example 2 was:

Embedded image 0.5 g of a branched siloxane / silalkylene copolymer represented by the following formula (an amount in which the number of moles of silicon-bonded hydrogen atoms is 0.2 per mole of alkenyl groups in the organopolysiloxane) and tetrabutoxytitanium 0 .5g
(1% by weight) and uniformly mixed in a dry atmosphere to obtain a reaction mixture having a viscosity of 170 poise. Next, 0.3 g of a toluene solution of a platinum divinyltetramethyldisiloxane complex having a platinum concentration of 0.5% (a platinum atomic weight of 0.3%) was added thereto.
003% by weight) and mixed quickly to prepare a curable organopolysiloxane composition. Tensile shear adhesive strength of the obtained curable organopolysiloxane composition was measured. The results are shown in Table 1.

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[Table 1]

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The curable organopolysiloxane composition of the present invention comprises the above components (A) to (D), and particularly contains a specific amount of the branched siloxane / silalkylene copolymer (B). Therefore, it has the characteristic that it rapidly thickens at room temperature and then the curing reaction further proceeds due to moisture in the atmosphere to become an elastic body.

Claims (3)

[Claims] (A) (a) Average unit formula: R ¹ _a SiO
_{(4-a) / 2} (wherein, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group or an alkoxy group, and at least 8 of R ¹
0 mol% is a substituted or unsubstituted monovalent hydrocarbon group, and in this monovalent hydrocarbon group, at least 2 mol%
Is an alkenyl group. a is a number from 0.75 to 2.5. ) In the molecule: R ¹ SiO _3/2 (wherein R
¹ is the same as above. 40 to 60% by weight of an organopolysiloxane containing a trifunctional unit represented by the formula or a tetrafunctional unit represented by the formula: SiO _4/2 , and (b) a viscosity at 25 ° C. of 1 to 1,000 poise. An organopolysiloxane containing at least three silicon-bonded alkoxy groups in one molecule (however, the organopolysiloxane does not contain an alkenyl group) in an amount of 60 to 40% by weight, and (B) a general formula: Wherein R ² is an alkyl or aryl group having 1 to 10 carbon atoms, b is 3 or 4, and X ¹ is i
= 1, which is a silylalkyl group represented by the following formula. Embedded image (Wherein, R ² is the same as above, and R ³ has 2 to 2 carbon atoms.
10 alkylene groups, and R ⁴ has 1 to 10 carbon atoms.
Is an alkyl group. X ^{i + 1} is a hydrogen atom or the above silylalkyl group, while X ^{i + 1} located at the terminal of the molecular chain is a hydrogen atom. i is an integer of from 1 to 10, which shows the hierarchy of the silylalkyl group, c ⁱ is an integer of 0 to 3, the average total number of c ⁱ in one molecule or less 1.5 ⁱ × b is there. ) The number of moles of silicon-bonded hydrogen atoms per mole of alkenyl groups in the branched siloxane / silalkylene copolymer (A) component containing silicon-bonded hydrogen atoms represented by｝ is from 0.3 to 3. Amount to be 0 (C) Condensation reaction accelerating catalyst Catalyst amount and (D) Addition reaction accelerating catalyst
A curable organopolysiloxane composition comprising a catalyst and having a viscosity at 25 ° C. of 30,000 poise or less. Wherein component (a), the average composition formula: (R ⁵ ₃ Si
O _{1/2) d} (in SiO _{4/2) e} (wherein, R ⁵ is a substituted or unsubstituted monovalent hydrocarbon radical containing at least 2 mol% of alkenyl groups, d / e = 0.2~ The curable organopolysiloxane composition according to claim 1, which is an organopolysiloxane represented by the following formula: Wherein component (a) has an average composition formula: (R ⁵ ₃ Si
O _1/2 ) _f (R ⁵ SiO _3/2 ) _g (SiO _4/2 ) _h (R
⁶ O _1/2 ) _j (wherein, R ⁵ is a substituted or unsubstituted monovalent hydrocarbon group containing at least 2 mol% of an alkenyl group;
⁶ is an alkyl group, f / h = 0.2 to 1.5,
g / h = 0.05-0.2 and j / h = 0.05-0.2
0.6. The curable organopolysiloxane composition according to claim 1, which is an organopolysiloxane represented by the formula: