JP2017095603A - Room temperature curable polyorganosiloxane composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a room temperature curable polyorganosiloxane composition less in reduction of physical properties such as hardness of a cured article or the like and adhesiveness under high temperature and high humidity environment.SOLUTION: There is provided a room temperature curable polyorganosiloxane composition containing (A) polyorganosiloxane of which a molecular chain terminal is encapsulated by a hydroxyl group or an alkoxy group of 100 pts.mass, (B) one or more kind selected from calcium carbonate and silica of 1 to 300 pts.mass, (C) polyorganosiloxane represented by (RSiO)(RSiO)(RSiO)(1), where p+q+r is 1, q/(p+q+r) is 0.01 to 0.8 and r/(p+q+r) is 0.01 to 0.8, and having viscosity at 23°C of 20 to 200,000 mPa s of 0.1 to 30 pts.mass, (D) a trivalent or tetravalent silane compound of 0.1 to 20 pts.mass and (E) a titanium chelate catalyst of 0.1 to 10 pts.mass.SELECTED DRAWING: None

Description

  The present invention relates to a condensation reaction type polyorganosiloxane composition that cures at room temperature to produce a rubbery elastic body.

  Curing at room temperature by contact with moisture in the air for applications such as adhesives and sealing materials for solar system parts, automotive parts, electrical / electronic equipment parts, sealing materials for FIPG (field forming gasket), potting materials, etc. Thus, a condensation reaction type silicone rubber composition that produces a rubber-like elastic body is used.

  Such a composition is obtained by blending a silanol group-terminated polyorganosiloxane whose molecular terminal is blocked with a hydroxyl group with a crosslinking agent having more than two hydrolyzable groups in the molecule. Depending on the conditions, carboxylic acid such as acetic acid, organic amine, amide, organic hydroxylamine, oxime compound, alcohol, acetone and the like are released during curing.

  Of these, the dealcohol-free type can be obtained not only at a low cost from alkoxysilane as a cross-linking agent, but also from an easily volatile alcohol such as methanol or ethanol, and has no unpleasant odor. It is widely used as a coating agent for electrical and electronic equipment.

  However, the dealcohol-free type is generally slow to cure, and the alcohol generated by hydrolysis of the cross-linking agent with a small amount of moisture present in the system during storage cleaves the molecular chain of the base polymer. There was the difficulty that stability was bad. Also, the adhesiveness was not sufficient depending on the application.

  In order to solve these problems, polyorganosiloxane having both ends or one end as a dialkoxysilyl group or trialkoxysilyl group is used as a base polymer, and surface-treated silica or a surface treatment is not used as a filler. By combining silica or the like with alkoxysilane as a crosslinking agent and further with a catalyst such as titanium chelate, various physical properties after curing such as adhesion, adhesion durability, and releasability are improved (for example, Patent Documents 1 to 3). 3).

  In addition, a polyorganosiloxane having dialkoxysilyl groups bonded to both ends, two to three alkoxy groups bonded to silicon atoms at one end, and one alkoxy group bonded to silicon atoms at the other end The base polymer is a mixture with polyorganosiloxane, and fine powder silica is used as a filler to improve adhesion durability and modulus, etc. to the substrate, and have a silicon atom-bonded alkoxy group at the end of the molecular chain. Non-sag, extrusion by using diorganopolysiloxane as a base polymer, using surface-hydrophobized silica and non-hydrophobized silica as filler, and further adding light stabilizer and / or UV absorber. Proposals have been made to improve the performance (see, for example, Patent Documents 4 to 6).

  However, all of the polyorganosiloxane compositions described in Patent Documents 1 to 6 have a problem that physical properties such as hardness of the cured product and adhesiveness are remarkably lowered at high temperature and high humidity. there were.

JP 2013-124343 A JP 2005-82734 A JP 2004-269818 A JP 2003-49072 A JP 2002-302606 A JP 2002-356616 A

  The present invention has been made to solve such problems of the prior art, and does not cause a decrease in physical properties such as hardness of a cured product under a high temperature and high humidity atmosphere, or a decrease in physical properties. An object of the present invention is to provide a room temperature-curable polyorganosiloxane composition having excellent properties such as low content and excellent adhesion durability.

The room temperature-curable polyorganosiloxane composition of the present invention has (A) 100 parts by mass of a polyorganosiloxane having a molecular chain terminal blocked with a hydroxyl group or an alkoxy group and a viscosity at 23 ° C. of 100 to 200,000 mPa · s, (B) 1 to 300 parts by mass selected from calcium carbonate and silica as filler, and (C) average unit formula: (R ¹ ₃ SiO _1/2 ) _p (R ¹ ₂ SiO _2/2 ) _Q (R ¹ SiO _3/2 ) _r (1) (In the formula (1), R ¹ is the same or different unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and p + q + r is 1. Q / (p + q + r) is from 0.01 to 0.8, and r / (p + q + r) is from 0.01 to 0.8), and the viscosity at 23 ° C. is from 20 to 200, Poly is 000 mPa · s Lugano siloxane, 0.1 to 30 parts by weight, (D) the general _{^{formula: R 2 n Si (OR 3}} ) 4-n ... (2) ( wherein, ^{R 2} are the same or different substituted or unsubstituted monovalent R ³ is the same or different unsubstituted monovalent hydrocarbon group, and n is 0 or 1.), and a trifunctional or tetrafunctional silane compound And / or 0.1-20 parts by mass of a partially hydrolyzed condensate thereof and (E) 0.1-10 parts by mass of a titanium chelate catalyst.

In this specification, R is a monovalent organic group, a monofunctional siloxy unit represented by the formula: R ₃ SiO _1/2 , and a bifunctional siloxy represented by the formula: R ₂ SiO _2/2 Unit and Formula: The trifunctional siloxy unit formula represented by RSiO _3/2 may be referred to as M unit, D unit, and T unit, which are abbreviations commonly used in the art, respectively.

  According to the room temperature curable polyorganosiloxane composition of the present invention, a cured product having good physical properties such as hardness is obtained, and the cured product has physical properties such as hardness even in a high temperature / high humidity atmosphere. There is little deterioration of the physical properties or physical properties are not deteriorated, and it has excellent adhesion durability.

Embodiments of the present invention will be described.
The room temperature-curable polyorganosiloxane composition according to an embodiment of the present invention includes (A) a polyorganosiloxane whose molecular chain end is blocked with a hydroxyl group or an alkoxy group, (B) a filler, and (C) a three-dimensional network structure. (D) a trifunctional or tetrafunctional silane compound or a partial hydrolysis condensate thereof, and (E) a titanium chelate catalyst. The polyorganosiloxane composition comprises (F) an adhesion-imparting agent and (G) a linear polyorgano in which the molecular chain ends are blocked with a group other than a hydrolyzable group such as a hydroxyl group or an alkoxy group. Siloxane can further be contained. Specifically, the component (G) can contain polydimethylsiloxane having molecular chain terminals blocked with methyl groups or vinyl groups.
Hereinafter, each component contained in the room temperature curable polyorganosiloxane composition of the present invention will be described.

<(A) Terminal hydroxyl group or alkoxy group-blocked polyorganosiloxane>
The component (A) is a polyorganosiloxane whose molecular chain end is blocked with a hydroxyl group (hydroxyl group) or an alkoxy group, and is a base component of the room temperature curable composition of the present invention. If the viscosity of the component (A) is too low, the rubber elasticity after curing becomes poor, and if it is too high, the workability is lowered. Therefore, the viscosity at 23 ° C. is preferably in the range of 100 to 200,000 mPa · s. The range of 000 to 100,000 mPa · s is more preferable.

The molecular structure of the polyorganosiloxane is preferably a straight chain represented by the following general formula (3), but may have a partially branched structure.

In formula (3), ^{R 4} represents a monovalent hydrocarbon group which may substituted or unsubstituted be the same or different, monovalent organic ^{R 5} is represented by -ZSiR ⁶ _{3-a X} a Represents a group. Here, Z represents oxygen (oxo group) or a divalent hydrocarbon group, and R ⁶ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same as or different from each other. X represents a hydroxyl group (hydroxyl group) or an alkoxy group, and a is an integer of 1 to 3. Moreover, m is a number which makes the viscosity at 23 degreeC of the said (A) component the range of 100-200,000 mPa * s.

R ⁴ includes methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, decyl group, alkyl group such as dodecyl group; alkenyl group such as vinyl group and allyl group; phenyl group And aryl groups such as tolyl group and xylyl group; and aralkyl groups such as 2-phenylethyl group and 2-phenylpropyl group. In addition, hydrogen atoms of these hydrocarbon groups are substituted with other atoms or groups, that is, halogens such as chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group A substituted hydrocarbon group such as a cyanoalkyl group such as a 3-cyanopropyl group. It is easy to synthesize, and the component (A) has a low viscosity with respect to the molecular weight, gives good extrudability to the composition before curing, and gives good physical properties to the composition after curing. it from is preferably 85% or more of the total R ⁴ is a methyl group, and more preferably substantially all R ⁴ are methyl groups.

In particular, when imparting heat resistance, radiation resistance, cold resistance or transparency to the composition, a necessary amount of phenyl groups as part of R ⁴ , when imparting oil resistance and solvent resistance, When a 3,3,3-trifluoropropyl group or 3-cyanopropyl group is provided as a part of R ⁴ or a surface having coating suitability is provided, a long chain alkyl group or an aralkyl group is provided as a part of R ^4. Can be arbitrarily selected depending on the purpose, for example, in combination with a methyl group.

The terminal group R ^{5 of the} component (A) is a silicon-functional siloxy unit represented by the formula: —ZSiR ⁶ _3-a X _a and having at least one hydroxyl group or hydroxyl group that is a silicon functional group. is there. Therefore, the component (A) of the embodiment has at least one hydroxyl group (hydroxyl group) or alkoxy group X at both ends of the molecule.

In the terminal group R ⁵ , R ⁶ bonded to the silicon atom is a substituted or unsubstituted monovalent hydrocarbon group which may be the same as or different from each other, and examples thereof are the same as those described above for R ⁴ . R ⁶ may be the same as or different from R ⁴ . A methyl group or a vinyl group is preferred because synthesis is easy and the reactivity of the hydrolyzable group X is excellent. Z is a divalent oxygen (oxy group) or a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include an alkylene group such as a methylene group, an ethylene group and a trimethylene group; a phenylene group and the like. Is done. From the viewpoint of easy synthesis, an oxy group or an ethylene group is preferable, and an oxy group is particularly preferable.

X is a hydroxyl group (hydroxyl group) or an alkoxy group present in at least one of R ⁵ as a terminal group. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. The plurality of alkoxy groups may be the same or different.

In the terminal group R ⁵ , the number a of the hydroxyl group or alkoxy group X is preferably 1 to 3. A silicon-functional polydiorganosiloxane in which X is a hydroxyl group is a ring-opening polymerization or ring-opening copolymerization of a cyclic diorganosiloxane low monomer such as octamethylcyclosiloxane in the presence of water using an acidic catalyst or an alkaline catalyst. And by introducing a hydroxyl group bonded to a silicon atom into the terminal of the linear polydiorganosiloxane.

The silicon-functional polydiorganosiloxane in which X is an alkoxy group can be synthesized, for example, by condensing a silane having two or more arbitrary alkoxy groups with a polyorganosiloxane having a hydroxyl group at the terminal. In this case, since one alkoxy group of the silane is consumed by the condensation reaction, the number of X in the terminal group R ² of the polyorganosilosan obtained by the reaction is the alkoxy group of the alkoxy group-containing silane used. One less than the number of.

Examples of the siloxy group at the end of the molecular chain blocked with a hydroxyl group include a dimethylhydroxysiloxy group and a methylphenylhydroxysiloxy group. Examples of the siloxy group at the end of the molecular chain blocked with an alkoxy group include vinyl dimethoxysiloxy group, methyldimethoxysiloxy group, trimethoxysiloxy group, methyldiethoxysiloxy group, triethoxysiloxy group and the like.
Specific examples of the component (A) include the following polyorganosiloxanes in which these siloxy groups are bonded to at least one terminal of a molecular chain, that is, dimethylpolysiloxane, methylethylpolysiloxane, methyloctylpolysiloxane, methyl Vinyl polysiloxane, methylphenyl polysiloxane, methyl (3,3,3-trifluoropropyl) polysiloxane, copolymer of dimethylsiloxane and methylphenylsiloxane, dimethylsiloxane and methyl (3,3,3-trifluoropropyl) Examples include siloxane copolymers.

  As the component (A), the terminal hydroxyl group or alkoxy group-blocked polyorganosiloxane may be used alone or in combination of two or more.

<(B) Filler>
In the room temperature curable polyorganosiloxane composition of the present invention, the filler as component (B) functions to impart consistency to the composition and to impart mechanical strength to the cured product. (B) The filler is calcium carbonate or silica. The filler which is (B) component may be used individually by 1 type, and may use 2 or more types together.

  As calcium carbonate, both heavy calcium carbonate and synthetic (light) calcium carbonate can be used. As silica, fumed silica, calcined silica, precipitated silica, quartz fine powder, and the like can be used.

  Moreover, you may use what processed the surface of these calcium carbonate or silica by silanes, silazanes, low polymerization degree siloxane, or an organic compound. Examples of the organic compound include fatty acids such as stearic acid and palmitic acid, resin (rosin) acid, ester compounds, and the like.

  Calcium carbonate is preferably used as the filler (B) because it imparts high fluidity to the composition before curing and imparts high mechanical strength to the cured product. When calcium carbonate is used, the particle size (average particle size) is preferably in the range of 0.005 to 10 μm. When the average particle size of calcium carbonate exceeds 10 μm, not only the mechanical properties of the cured product are deteriorated, but also the extensibility of the cured product is not sufficient. When the average particle size is less than 0.005 μm, the viscosity of the composition before curing increases and the fluidity decreases. The value of the average particle diameter may be a value measured by image analysis with an electron microscope, or may be obtained from an average particle diameter converted from a specific surface area, or a 50% diameter by weight conversion from a particle size distribution. Alternatively, the average particle diameter or an average particle diameter measured by a laser diffraction / scattering method may be used.

  Further, as described above, calcium carbonate having a surface treated with a fatty acid, a resin (rosin) acid, an ester compound, or the like may be used in addition to the surface of the calcium carbonate that has not been treated. When calcium carbonate surface-treated with a fatty acid or the like is used, the dispersibility of calcium carbonate is improved, so that the processability of the composition is improved. As the surface treatment agent for calcium carbonate, stearic acid, an ester compound of stearic acid, and rosin acid are particularly preferable. The surface treatment degree is preferably in the range of 2.0 to 3.5% by mass. When the surface treatment degree exceeds 3.5% by mass, not only the storage stability is lowered and the curability is lowered, but also the cured product has insufficient mechanical properties. When the degree of surface treatment is less than 2.0% by mass, the effects of improving dispersibility, improving appearance, and improving adhesiveness and workability due to surface treatment are not sufficiently improved. The surface treatment degree is a value measured by differential thermal analysis.

  (B) The compounding quantity of a filler is 1-300 mass parts with respect to 100 mass parts of said (A) component, Preferably it is 5-150 mass parts. If the amount is less than 1 part by mass, sufficient effects such as reinforcement by blending cannot be obtained. If the amount exceeds 300 parts by mass, workability such as dischargeability and flow characteristics are deteriorated.

<(C) Polyorganosiloxane>
(C) Average unit formula contained in the room temperature curable polyorganosiloxane composition of the present invention: (R ¹ ₃ SiO _1/2 ) _p (R ¹ ₂ SiO _2/2 ) _q (R ¹ SiO _3/2 ) _R (1) (In the formula (1), R ¹ is the same or different unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and q / (p + q + r) is 0.01 to 0.00. The polyorganosiloxane (hereinafter also referred to as “MDT oil”) represented by 8) has all of M units, D units, and T units, and has a three-dimensional network structure. Therefore, the apparent crosslink density of the cured product is increased, thereby suppressing a decrease in physical properties and adhesive strength of the cured product in a high temperature / high humidity atmosphere. As the component (C), one type may be used alone, or two or more types may be used in combination, but since it is easy to mix, it is preferable to use one type alone.

In Formula (1), R ¹ is a monovalent hydrocarbon group having 1 to 20 carbon atoms which may be the same or different from each other. Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, and a dodecyl group; A cycloalkyl group such as a group; an alkenyl group such as a vinyl group or an allyl group; an aryl group such as a phenyl group, a tolyl group or a xylyl group; a benzyl group, a 2-phenylethyl group or a 2-phenylpropyl group; Aralkyl group and the like can be mentioned. Preferably they are an alkyl group, an alkenyl group, and an aryl group, More preferably, they are a methyl group, a vinyl group, and a phenyl group.

  As for the viscosity of (C) component, the viscosity in 23 degreeC is 20-200,000 mPa * s. If the viscosity of the component (C) is too low, the rubber after curing becomes brittle, and if it is too high, the workability deteriorates, such as a decrease in dischargeability. Therefore, the viscosity at 23 ° C. is 40-100,000 mPa · s. A range is more preferred.

  In the component (C), the ratio (q / (p + q + r)) of D units to the total number of moles of M units, D units, and T units is 0.01 to 0.8. q / (p + q + r) is preferably from 0.1 to 0.7, more preferably from 0.2 to 0.7, and even more preferably from 0.2 to 0.6.

  In the component (C), the ratio of M units to the total number of moles of units (p / (p + q + r)) is preferably 0.005 to 0.5, more preferably 0.05 to 0.4. Preferably, it is 0.05 to 0.3, more preferably 0.1 to 0.3. When the ratio of the M unit is 0.005 or more, it is possible to obtain an effect of suppressing deterioration of physical properties of the cured product under high temperature and high humidity. On the other hand, if the proportion of M units exceeds 0.5, the crosslinking density of the MDT oil itself is reduced, and the effect of suppressing the deterioration of the physical properties of the cured product under high temperature and high humidity and the effect of improving the adhesion durability. Is difficult to obtain.

  From the viewpoint of improving the effect of suppressing deterioration of physical properties and the like under high temperature and high humidity of the cured product and the effect of improving adhesion durability, the ratio of T unit to the number of moles of all units (r / ( p + q + r)) is 0.01 to 0.8. r / (p + q + r) is preferably from 0.1 to 0.7, more preferably from 0.2 to 0.7, and even more preferably from 0.2 to 0.6.

  From the same viewpoint, the ratio (p / r) of the number of moles of M units and T units in the component (C) is preferably 0.006 to 1, and 0.07 to 0.6. It is more preferable. When p / r is within the above range, the three-dimensional network structure of the component (C) can further reduce the deterioration of physical properties of the cured product under high temperature and high humidity and the effect of improving the adhesion durability. Can be improved.

  Furthermore, the weight average molecular weight (Mw) of (C) component has the preferable range of 500-300,000, and the range of 500-150,000 is more preferable. The weight average molecular weight (Mw) is a value determined by GPC (gel permeation chromatograph) based on polystyrene.

  As a method for producing the (C) component polyorganosiloxane, a known method may be used. For example, there is a method in which a compound such as organochlorosilane, which is a source of each unit of M unit, D unit, and T unit, is mixed at the above-mentioned ratio, then co-hydrolyzed in the presence of an acid or alkali, and then condensed. Can be mentioned.

  (C) The compounding quantity of a component is 0.1-30 mass parts with respect to 100 mass parts of said (A) component, Preferably it is 0.5-15 mass parts. If it is less than 0.1 mass part, the effect which improves the fall of the physical characteristic etc. in the high temperature and high-humidity atmosphere of hardened | cured material is not fully acquired. When it exceeds 30 mass parts, physical properties, such as elasticity of hardened | cured material, will fall.

<(D) Silane compound or partially hydrolyzed condensate thereof>
In the room temperature curable polyorganosiloxane composition of the present invention, (D) the silane compound or a partially hydrolyzed condensate thereof is a trifunctional compound represented by the formula: R ² _n Si (OR ³ ) _4-n (2) Or a tetrafunctional silane compound, or a partially hydrolyzed condensate thereof, and acts as a crosslinking agent for the components (A) and (C).

In formula (2), R ² is a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other. Examples thereof include the same groups as those described above for R ⁴ in formula (3) representing the component (A). All of the above statements regarding R ⁴ also apply to R ² . R ³ is an unsubstituted monovalent hydrocarbon group which may be the same or different from each other. Examples of R ³ include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, decyl group, and dodecyl group. R ² and R ³ are preferably a methyl group, an ethyl group, or a propyl group. n is 0 or 1.

  Such a partial hydrolysis-condensation product of a trifunctional or tetrafunctional silane compound preferably has 3 to 20 Si atoms, more preferably 4 to 15 molecules. If the number of Si is less than 3, sufficient curability cannot be obtained. Moreover, when Si number exceeds 20, sclerosis | hardenability and the mechanical characteristic after hardening will fall. As the component (D), the silane compound or its partial hydrolysis-condensation product may be used alone or in combination of two or more.

  (D) The compounding quantity of a component is 0.1-20 mass parts with respect to 100 mass parts of said (A) component, Preferably it is 1-10 mass parts. If the amount is less than 0.1 part by mass, crosslinking is not sufficiently performed and not only a cured product having low hardness is obtained, but also the storage stability of the composition containing the crosslinking agent becomes poor. If it exceeds 20 parts by mass, the shrinkage rate during curing increases, and the physical properties such as elasticity of the cured product decrease.

<(E) Titanium chelate catalyst>
In the present invention, the titanium chelate catalyst as the component (E) promotes the condensation reaction between the hydroxyl group (hydroxyl group) and / or the alkoxy group of the component (A) and the alkoxy group of the component (D). It is a catalyst that works to promote the curing of. (E) Titanium chelate catalysts include diisopropoxy bis (ethyl acetoacetate) titanium, diisopropoxy bis (methyl acetoacetate) titanium, diisopropoxy bis (acetylacetone) titanium, dibutoxy bis (ethyl acetoacetate) titanium, dimethoxy bis Well-known titanium chelate compounds, such as (ethyl acetoacetate) titanium, are mentioned.

  (E) It is preferable that the compounding quantity of a titanium chelate catalyst shall be 0.1-10 mass parts with respect to 100 mass parts of said (A) component, and 1-5 mass parts is more preferable.

<(F) Adhesiveness imparting agent>
The room temperature curable polyorganosiloxane composition of the present invention preferably contains, as an optional component, (F) an adhesion-imparting agent that further improves the adhesion and adhesion durability of the composition. (F) As an adhesion imparting agent, an isocyanurate compound having a dialkoxysilylpropyl group or a trialkoxysilylpropyl group as shown in the following chemical formula can be used. Among these isocyanurate compounds, tris (N-trialkoxysilylpropyl) isocyanurate is particularly preferable.

Further, as the (F) tackifier, the general ^formula: the silane compound represented by _{R 7} 4-s SiY _q it can also be used. In the formula, R ⁷ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same as or different from each other, and Y represents a hydrolyzable group. Further, s is a number exceeding 2 on average and 4 or less. Examples of R ⁷ include substituted amino groups, epoxy groups, isocyanato groups, (meth) acryloxy groups, mercapto groups, alkyl groups substituted with halogen atoms, and phenyl groups. Examples of the substituted alkyl group include a substituted methyl group, a 3-substituted propyl group, and a 4-substituted butyl group, but a 3-substituted propyl group is preferable because of easy synthesis.

  (F) Examples of the silane compound having the general formula that can be used as an adhesion-imparting agent include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltriisopropoxysilane, and 3-aminopropyl. Triacetamidosilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, N-methyl-3-aminopropyltrimethoxysilane, Substituted or unsubstituted amino group-containing silanes such as N-phenyl-3-aminopropyltrimethoxysilane, N, N-dimethyl-3-aminopropyltrimethoxysilane; 3-glycidoxytrimethoxysilane, 3-glycid Xymethyldimethoxysilane, 3,4-epoxycyclohexane Epoxy group-containing silanes such as xylethyltrimethoxysilane; 3-isocyanatopropyltrimethoxysilane, isocyanato group-containing silanes such as 3-isocyanatopropylmethyldimethoxysilane; 3-acryloxypropyltrimethoxysilane, 3-methacrylate (Meth) acryloxy group-containing silanes such as loxypropyltrimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane; mercapto group-containing silanes such as 3-mercaptopropyltrimethoxysilane; and Illustrative are halogen atom-containing silanes such as 3-chloropropyltrimethoxysilane. Among these, (E) the epoxy group-containing silane and the isocyanato group-containing silane that have little influence on the titanium chelate catalyst are more preferable. Further, it is preferable to use a mixture or reaction product of an amino group-containing silane and an epoxy group-containing silane.

  From the viewpoint of compatibility with the composition, the (F) adhesion promoter is preferably blended in an amount of 0.01 to 5 parts by mass with respect to 100 parts by mass of the component (A). If it is less than 0.01 parts by mass, the effect of improving the adhesiveness is small and the onset thereof is slow. When the amount exceeds 5 parts by mass, not only separation during storage and shrinkage of the cured product occurs, but storage stability and workability deteriorate, and yellowing may occur. A range of 0.1 to 2 parts by mass is more preferable.

  In the room temperature curable polyorganosiloxane composition of the present invention, (G) molecular chain terminals are blocked with methyl groups or vinyl groups in order to adjust the viscosity and facilitate the blending of the (B) filler. It is preferable to blend polyorganosiloxane (hereinafter referred to as a blocked polyorganosiloxane such as a terminal methyl group). (G) As the terminal methyl group-capped polyorganosiloxane, a linear polydimethylsiloxane having a trimethylsilyl group bonded to both ends of the molecular chain, a linear polydimethylsiloxane having a vinyldimethylsilyl group bonded to both ends of the molecular chain Examples include polydimethylsiloxane.

  The viscosity at 23 ° C. of the terminal methyl group-capped polyorganosiloxane as component (G) is preferably 10 to 20,000 mPa · s. In particular, the viscosity is preferably lower than the viscosity of the component (A) so that the viscosity of the composition can be easily adjusted.

  The amount of component (G) is adjusted so that the finally obtained composition has a desired viscosity. (A) 0.1-100 mass parts is preferable with respect to 100 mass parts of component, More preferably, you may be 5-40 mass parts.

<Other ingredients>
The room temperature curable polyorganosiloxane composition of the present invention includes various kinds of agents such as a thixotropic agent, a pigment, a flame retardant, an organic solvent, an antifungal agent, an antibacterial agent, an ultraviolet absorber, and a heat resistance improver as necessary. Functional additives can be added.

  The room temperature-curable polyorganosiloxane composition of the present invention is prepared by drying predetermined amounts of the components (A) to (E) and, if necessary, the components (F), (G), and other components described above. By mixing uniformly in the atmosphere, it is obtained as a one-component room temperature curable composition. When this composition is exposed to air, the crosslinking reaction proceeds due to moisture, and the composition is cured into a rubber elastic body. It can also be prepared as a two-component room temperature curable composition. In the two-pack type composition, the main agent and the curing agent are mixed in the air to be cured in the same manner as the one-pack type room temperature curable composition.

The room temperature curable polyorganosiloxane composition of the present invention is stable under sealed conditions in the absence of moisture, and is cured at room temperature upon contact with moisture in the air to produce a rubbery elastic body. In particular, a composition having a high curing rate and excellent deep part curability and excellent adhesion to various substrates can be obtained. And even if it is left in a high temperature and high humidity atmosphere for a long time, the physical properties such as the hardness of the cured product are hardly decreased, or the physical properties of the cured product are hardly decreased, and the adhesive durability is excellent. Yes.
Therefore, the composition of the present invention is useful as an elastic adhesive, coating material, potting material, etc. for solar parts, automobile parts, parts for electric and electronic devices, and also as a field forming gasket, a sealing material for construction, etc. Useful.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In Examples and Comparative Examples, “part” means “part by mass”, and all physical properties such as viscosity are values at 23 ° C. and 50% relative humidity.

The compounds used in the examples are as follows.
(A) component (A1) α, ω-dihydroxypolydimethylsiloxane (viscosity: 50,000 mPa · s)
(A2) Polydimethylsiloxane blocked at both ends with methyldimethoxysilyl groups (viscosity: 40,000 mPa · s)
(A3) Polydimethylsiloxane blocked at both ends with a trimethoxysilyl group (viscosity: 20,000 mPa · s)

(B) Component (B1) Light calcium carbonate surface-treated with fatty acid (stearic acid) (average particle size: 0.05 μm)
(B2) Light calcium carbonate surface-treated with fatty acid (stearic acid) ester (average particle size: 0.05 μm)
(B3) Dry silica surface-treated with octamethylcyclotetrasiloxane (specific surface area by BET method: 160 m ² / g)
(B4) Heavy calcium carbonate not subjected to surface treatment (average particle size: 2.2 μm)

Component (C) _{(C1) M p D q T} r dimethyl oil (p = 0.1, q = 0.6 , r = 0.3)
_{(C2) M p D q T} r dimethyl oil (p = 0.2, q = 0.4 , r = 0.4)
_{(C3) M p D q T} r dimethyl oil (p = 0.3, q = 0.2 , r = 0.5)
_{(C4) M p D q T} r dimethyl oil (p = 0.600, q = 0.395 , r = 0.005)

(D) Component (D1) Methyltrimethoxysilane (D2) Vinyltrimethoxysilane

(E) component (E1) diisopropoxybis (ethylacetoacetate) titanium (E2) diisopropoxybis (acetylacetate) titanium

(F) component (F1) 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate (F2) aminoethylaminopropyltrimethoxysilane

    (G) Trimethylsilyl group-blocked polydimethylsiloxane (viscosity: 100 mPa · s)

<(C) Production of MDT dimethyl oil>
MDT dimethyl oil was produced as follows.

(C1) M _0.1 D _0.6 T _0.3 dimethyl oil (M _p D _q T _r dimethyl oil (p = 0.1, q = 0.6, r = 0.3))
100 parts of dimethyldichlorosilane, 30 parts of methyltrichlorosilane, and 4 parts of trimethylchlorosilane were blended, and while stirring and stirring for 1 hour, 320 parts of water was added dropwise to this mixture over 3 hours, followed by addition at 40 ° C or lower. Water splitting and subsequent condensation reaction were performed. After completion of the dropwise addition, the mixture was stirred for 1 hour and then allowed to stand for 10 minutes to separate the hydrochloric acid layer. Thereafter, washing with water and standing were repeated, and the aqueous phase and the oil phase were separated to obtain MDT dimethyl oil as the oil phase. The obtained (C1) M _p D _q T _r dimethyl oil has a viscosity at 23 ° C. of 56 mPa · s, a weight average molecular weight (Mw) of 3,500, and D units relative to the total of M units, D units, and T units. The molar ratio (q / (p + q + r)) was 0.6. The average unit formula is (Me ₃ SiO _1/2 ) _0.1 (Me ₂ SiO _2/2 ) _0.6 (MeSiO _3/2 ) _0.3 (wherein Me is a methyl group (—CH ₃ )). ).

_{(C2) M p D q T} r dimethyl oil (p = 0.2, q = 0.4 , r = 0.4)
In the production of (C1) M _p D _q T _r dimethyl oil (p = 0.1, q = 0.6, r = 0.3), the ratio of dimethyldichlorosilane, methyltrichlorosilane, and trimethylchlorosilane was changed. in addition to the changes, in the same manner as in the production of _{(C1) M p D q T} r dimethyl oil was produced _{(C2) M p D q T} r dimethyl oil. The resulting _{(C2) M p D q T} r dimethyl oil has a viscosity at 23 ° C. is 115 mPa · s, a weight average molecular weight (Mw) of 6,800. The average unit formula is (Me ₃ SiO _1/2 ) _0.2 (Me ₂ SiO _2/2 ) _0.4 (MeSiO _3/2 ) _0.4 (wherein Me is a methyl group (—CH ₃ )). Is shown.)

_{(C3) M p D q T} r dimethyl oil (p = 0.3, q = 0.2 , r = 0.5)
(C1) M _p D _q T _r Dimethyl oil (p = 0.1, q = 0.6, r = 0.3) In the production of dimethyl oil, dimethyldichlorosilane, methyltrichlorosilane, and trimethylchlorosilane (C3) M _p D _q T _r dimethyl oil was produced in the same manner as in the production of (C1) M _p D _q T _r dimethyl oil, except that the ratio was changed. The obtained (C3) M _p D _q T dimethyl oil had a viscosity at 23 ° C. of 188 mPa · s and a weight average molecular weight (Mw) of 8,400. The average unit formula is (Me ₃ SiO _1/2 ) _0.3 (Me ₂ SiO _2/2 ) _0.2 (MeSiO _3/2 ) _0.5 (wherein Me is a methyl group (—CH ₃ )). Is shown.)

_{(C4) M p D q T} r dimethyl oil (p = 0.600, q = 0.395 , r = 0.005)
In the production of (C1) M _p D _q T _r dimethyl oil (p = 0.1, q = 0.6, r = 0.3), the ratio of dimethyldichlorosilane, methyltrichlorosilane, and trimethylchlorosilane was changed. (C4) M _p D _q T _r dimethyl oil was produced in the same manner as in the production of (C1) M _p D _q T _r dimethyl oil, except for the change. The resulting _{(C4) M p D q T} r dimethyl oil has a viscosity at 23 ° C. is 22 mPa · s, a weight average molecular weight (Mw) of 1,800. The average unit formula is (Me ₃ SiO _1/2 ) _0.6 (Me ₂ SiO _2/2 ) _0.395 (MeSiO _3/2 ) _0.005 (wherein Me is a methyl group (—CH ₃ )). Is shown.)

Example 1
(A1) 100 parts of α, ω-dihydroxypolydimethylsiloxane (viscosity 50,000 mPa · s) blocked at both ends of the molecular chain with hydroxyl groups, (B1) light calcium carbonate surface-treated with stearic acid (average particle size 0) .05 μm, surface treatment degree 2.7% by mass) 128 parts, (G) 21 parts of polydimethylsiloxane (viscosity 100 mPa · s) having trimethylsiloxy groups bonded to both ends of the molecular chain, obtained above (C1) After 7 parts of M _p D _q T _r dimethyl oil (p = 0.1, q = 0.6, r = 0.3) were uniformly mixed, 6.8 parts of (D1) methyltrimethoxysilane, (E1) 2.0 parts of di (isopropoxy) bis (ethylacetoacetate) titanium and 0.3 part of (F1) 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate In addition, and mixed until uniform under a moisture-blocking, to give a polyorganosiloxane composition.

(Examples 2 to 15)
A polyorganosiloxane composition was prepared under the same conditions and steps as in Example 1 except that the types and blending amounts of components (A) to (G) were changed as shown in Table 1.

(Comparative Example 1)
In Example 1, instead of 7 parts of (C1) M _p D _q T _r dimethyl oil (p = 0.1, q = 0.6, r = 0.3), (G) trimethyl at both ends of the molecular chain 7 parts of polydimethylsiloxane having a siloxy group bonded thereto (viscosity: 100 mPa · s) was used in addition to 21 parts used for the same purpose as in the examples. Otherwise in the same manner as in Example 1, a polyorganosiloxane composition was prepared.

(Comparative Examples 2 to 4)
A polyorganosiloxane composition was prepared under the same conditions and steps as in Example 1 except that the types and blending amounts of components (A) to (G) were changed as shown in Table 1.

  Next, with respect to the polyorganosiloxane compositions obtained in Examples and Comparative Examples, physical properties and adhesive strength of the cured products were measured and evaluated at the initial stage and after being left in a high-temperature and high-humidity atmosphere by the following methods. In addition, as a physical characteristic of hardened | cured material, hardness, tensile strength, and elongation were measured. Table 1 shows the compositions and measurement results of the polyorganosiloxane compositions of Examples and Comparative Examples.

[Measurement of hardness, tensile strength and elongation]
The obtained polyorganosiloxane composition was dispensed and formed into a 2 mm sheet, and then allowed to cure for 7 days in an atmosphere of 23 ° C. and 50% RH. The hardness (initial hardness) of the cured product thus obtained was measured with a type A hardness meter. Further, the tensile strength was measured in accordance with JIS K 6249. Further, the elongation was measured according to JIS K 6249.

[Measurement of physical properties after standing in high temperature and high humidity atmosphere]
The cured product was left in an atmosphere of 85 ° C. and 85% RH for 500 hours and 1000 hours, and then the hardness of the cured product was measured with a type A hardness meter. Further, the tensile strength and elongation were measured by the above methods.

[Measurement of shear bond strength]
The polyorganosiloxane composition was applied to the surface of the base material (aluminum) so as to have a length of 10 mm, a width of 25 mm, and a thickness of 1 mm, and allowed to stand in an atmosphere of 23 ° C. and 50% RH for 7 days to cure. I let you. The test piece thus obtained was subjected to a tensile test with an autograph manufactured by Shimadzu Corporation at a tensile speed of 10 mm / min, and the shear bond strength (hereinafter also referred to as shear adhesive force) was measured.

[Measurement of shear adhesive strength after standing in high temperature and high humidity atmosphere]
The specimen prepared by the measurement of the shear adhesive strength was left in an atmosphere of 85 ° C. and 85% RH for 500 hours and 1000 hours, and then the shear adhesive strength was measured by the method described above.

  As can be seen from Table 1, (A) polydimethylsiloxane in which both ends of the molecular chain are blocked with hydroxyl groups, (B) calcium carbonate as filler, (C) MDT dimethyl oil, (D) trifunctional silane Example polyorganosiloxane compositions containing certain proportions of methyltrimethoxysilane and (E) titanium chelate catalyst have initial curing physical properties (hardness, tensile strength and elongation) and shear adhesion to aluminum. Excellent power. Furthermore, even if the cured product is left in a high temperature and high humidity atmosphere for a long time, the physical properties and the decrease in the shear adhesive strength to aluminum are small.

  On the other hand, the polyorganosiloxane composition of the comparative example in which (C) MDT dimethyl oil was not blended, and instead, polydimethylsiloxane in which both molecular chain ends were blocked with trimethylsilyl groups, It can be seen that when left in a humid atmosphere for a long time, the shear adhesive strength to aluminum is reduced.

According to the room temperature curable polyorganosiloxane composition of the present invention, the initial physical characteristics and adhesiveness are excellent, and the physical characteristics and adhesiveness are hardly lowered even when left in a high temperature and high humidity atmosphere for a long time. You can get things.
Therefore, the composition of the present invention is useful as an elastic adhesive for solar parts, automobile parts, electric / electronic devices, coating materials, potting materials, etc., and also useful as an on-site forming gasket, architectural sealing material, etc. It is.

Claims (6)

(A) 100 parts by mass of a polyorganosiloxane whose molecular chain terminal is blocked with a hydroxyl group or an alkoxy group and has a viscosity at 23 ° C. of 100 to 200,000 mPa · s;
(B) 1 to 300 parts by mass of at least one selected from calcium carbonate and silica as a filler;
(C) Average unit formula: (R ¹ ₃ SiO _1/2 ) _p (R ¹ ₂ SiO _2/2 ) _q (R ¹ SiO _3/2 ) _r (1)
(In the formula (1), R ¹ is the same or different unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, p, q and r are all positive numbers, and p + q + r is 1. q / (p + q + r) is 0.01 to 0.8, and r / (p + q + r) is 0.01 to 0.8).
0.1 to 30 parts by mass of a polyorganosiloxane having a viscosity at 23 ° C. of 20 to 200,000 mPa · s,
(D) General formula: R ² _n Si (OR ³ ) _4-n (2)
(In the formula, R ² is the same or different substituted or unsubstituted monovalent hydrocarbon group, R ³ is the same or different unsubstituted monovalent hydrocarbon group, and n is 0 or 1. 0.1 to 20 parts by mass of a trifunctional or tetrafunctional silane compound and / or a partially hydrolyzed condensate thereof,
(E) 0.1 to 10 parts by mass of a titanium chelate catalyst;
A room temperature-curable polyorganosiloxane composition comprising:   2. The room temperature-curable polyorganosiloxane composition according to claim 1, wherein in the polyorganosiloxane as the component (C), p / (p + q + r) is 0.01 to 0.8.   The room temperature curable polyorganosiloxane composition according to claim 1 or 2, wherein the polyorganosiloxane as the component (C) has a weight average molecular weight (Mw) of 500 to 300,000.   The room temperature-curable polyorganosiloxane composition according to any one of claims 1 to 3, wherein the filler as the component (B) is calcium carbonate surface-treated with a fatty acid.   Furthermore, (F) 0.01-5 mass parts of adhesive provision agents are contained, The room temperature curable polyorganosiloxane composition of any one of Claims 1 thru | or 4 characterized by the above-mentioned.   The room temperature-curable polyorganosiloxane composition according to any one of claims 1 to 5, wherein the (F) adhesion-imparting agent contains tris (N-trialkoxysilylpropyl) isocyanurate.