JP2019112509A - Room-temperature-curable polyorganosiloxane composition, cured product and laminate thereof - Google Patents

Abstract

To provide a room temperature-curable polyorganosiloxane composition that excels in storage stability, and surface curability and depth curability, and provides cured products excellent in mechanical property.SOLUTION: There is provided a room temperature-curable polyorganosiloxane composition including: (A) 100 pts.mass of a polyorganosiloxane mixture composed of (A1) 20 to 100 pts.mass of a polyorganosiloxane blocked with trialkoxysilyl groups at both terminals and (A2) 80 to 0 pts.mass of a polyorganosiloxane blocked with dialkoxysilyl groups at both terminals; (B) 1 to 100 pts.mass of an inorganic filler; (C) 0.5 to 15 pts.mass of a partial hydrolytic condensate of alkoxysilane represented by general formula: RSi(OR); (D) 0.1 to 10 pts.mass of a titanium chelate catalyst; and (E) 0.01 to 5 pts.mass of a tackifier.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a room temperature curable polyorganosiloxane composition and a cured product thereof and a laminate, and in particular, a room temperature curable polyorganosiloxane composition having good surface curability and deep area curability, and excellent storage stability. The present invention relates to a cured product and a laminate.

  Among polyorganosiloxane compositions which cure at room temperature to form a rubbery elastomer, those of the type in which a curing reaction takes place by contact with moisture in the air are the main body (base polymer) and the crosslinking immediately before use. As an elastic adhesive or coating agent in the electric / electronic industry, etc., since there is no complication in weighing the agent or catalyst and mixing these, there is no mistake in the formulation, and the adhesion is excellent. It is also widely used as a sealing agent for construction.

  Among them, polyorganosiloxanes having a dialkoxysilyl group or a trialkoxysilyl group, or a hydroxysilyl group at both or one end are used as a base polymer, to which light calcium carbonate and heavy calcium carbonate are used as inorganic fillers. And silica, etc., and by combining an alkoxysilane as a crosslinking agent and a titanium chelate catalyst etc., improvement of various physical properties after curing such as adhesiveness, adhesion durability, modulus and the like is achieved (for example, Patent Documents 1 to 3) reference).

JP 2001-152020 A Japanese Patent Application Publication No. 2003-49072 Japanese Patent Application Publication No. 2003-269818

  The present inventors mentioned that when the cured product of the conventional silicone rubber composition (silicone rubber) is formed on the surface of the transparent substrate, thin stains are generated in the vicinity of the outer periphery of the silicone rubber. The observation was made from the side opposite to the formed side of silicone rubber. This stain is considered to be that the unreacted component of the silicone rubber composition exudes to the outside of the silicone rubber due to insufficient deep curing. When such stains occur, the appearance may be impaired depending on the application.

  The present invention has been made to solve the above-mentioned problems, and is a room temperature curable polyorganosiloxane which is excellent in storage stability, excellent in surface curability and deep area curability, and gives a cured product of excellent mechanical properties. It is intended to provide a composition.

The room temperature-curable polyorganosiloxane composition of the present invention comprises (A) (A1) 20 to 100% by mass of a linear polyorganosiloxane blocked at both ends with a trialkoxysilyl group and (A2) both ends 100 parts by mass of a polyorganosiloxane mixture consisting of a mixture of 80 to 0% by mass of linear polyorganosiloxane blocked with alkoxysilyl group, 1 to 100 parts by mass of (B) inorganic filler, (C) general formula R ¹ _a Si (OR ² ) _4-a (wherein R ¹ is a monovalent hydrocarbon group, R ² is an alkyl group or an alkoxy substituted alkyl group, and a is 0, 1 or 2). Containing 0.5 to 15 parts by mass of the partially hydrolyzed condensate of alkoxysilane, 0.1 to 10 parts by mass of (D) a titanium chelate catalyst, and 0.01 to 5 parts by mass of (E) an adhesion imparting agent Characterized by To.

  In the room temperature curable polyorganosiloxane composition of the present invention, the (B) inorganic filler preferably comprises calcium carbonate or silica powder. Moreover, it is preferable that calcium carbonate consists of 1 or more types chosen from heavy calcium carbonate and light calcium carbonate.

  In the room temperature curable polyorganosiloxane composition of the present invention, the average degree of polymerization of the partially hydrolyzed condensate of (C) alkoxysilane is preferably 3 to 50.

  The cured product of the present invention is characterized in that the room temperature curable polyorganosiloxane composition of the present invention is cured.

  The laminate of the present invention is a laminate comprising a metal base, an adhesive resin disposed on the surface of the metal base, and a heat-resistant plate made of glass or glass ceramic disposed on the surface of the adhesive resin, The adhesive resin comprises the cured product of the present invention. Moreover, in the laminate of the present invention, it is preferable to provide a colored coating on the main surface on the adhesive resin side of the heat-resistant plate.

  In the present specification, “dialkoxysilyl group” is a terminal silicon atom in which two alkoxy groups and one monovalent hydrocarbon group (including a substituted hydrocarbon group) are bonded to each other. "Dialkoxymonoorganosilyl group".

According to the present invention, it is possible to provide a room temperature curable polyorganosiloxane composition which is excellent in storage stability, excellent in surface curability and deep area curability, and gives a cured product of excellent mechanical properties.
Further, according to the present invention, a cured product having excellent mechanical properties is obtained by curing the room temperature curable polyorganosiloxane composition of the present invention which is excellent in storage stability and excellent in surface curability and deep area curability. be able to.
Further, according to the present invention, by having a cured product obtained by the composition excellent in the above-mentioned surface curing property and deep part curing property, it is possible to obtain a laminate excellent in appearance without stain from the cured product. .

It is a sectional view showing an IH cooking appliance concerning an embodiment roughly.

Hereinafter, embodiments of the present invention will be described.
The room temperature curable polyorganosiloxane composition of the embodiment comprises 100 parts by mass of (A) polyorganosiloxane mixture, 1 to 100 parts by mass of (B) inorganic filler, (C) general formula: R ¹ _a Si (OR ² ) Partial hydrolysis of alkoxysilane represented by _4-a (wherein, R ¹ is a monovalent hydrocarbon group, R ² is an alkyl group or an alkoxy substituted alkyl group, and a is 0, 1 or 2) It contains 0.5 to 15 parts by mass of the decomposition condensate, (D) 0.1 to 10 parts by mass of a titanium chelate catalyst, and (E) 0.01 to 5 parts by mass of an adhesion promoter. Each of the above components will be described below.

  In this embodiment, the (A) polyorganosiloxane mixture is a base polymer of a room temperature curable polyorganosiloxane composition. (A) The polyorganosiloxane mixture is (A1) a linear polyorganosiloxane in which both ends are blocked with a trialkoxysilyl group (hereinafter also referred to as "both-end trialkoxysilyl group blocked polyorganosiloxane") and optional And (A2) a linear polyorganosiloxane in which both ends are blocked with a dialkoxysilyl group (hereinafter also referred to as “both-end dialkoxysilyl group blocked polyorganosiloxane”). The content of the component (A1) in the component (A) is 20 to 100% by mass with respect to the total amount of the component (A), and the content of the component (A2) is 80 to 80% with respect to the total amount of the component (A). It is 0 mass%.

  The component (A1) is, for example, an organopolysiloxane represented by the following general formula (A1).

In the above general formula (A1), R ³ is an alkyl group, and X is a divalent oxygen (oxy group) or a divalent hydrocarbon group. R ⁴ is a group selected from a monovalent hydrocarbon group, a halogenated hydrocarbon group and a cyanoalkyl group. The plurality of R ³ , R ⁴ and X may be identical to or different from one another.

  In the above general formula (A1), n represents the average polymerization degree of (A1) both terminal trialkoxysilyl group-blocked polyorganosiloxane, and the viscosity at 23 ° C. is preferably 0.02 to 1000 Pa · s, more preferably 0 .1 to 500 Pa.s, which is a positive number. Specifically, n is preferably 20 to 2500, and more preferably 80 to 2000.

  The viscosity at 23 ° C. of the component (A1) is preferably 0.02 to 1000 Pa · s, more preferably 0.1 to 500 Pa · s, as described above. The higher the viscosity of the component (A1), the better the surface curability. However, when the viscosity of the component (A1) is too low, the rubber elasticity after curing becomes poor, and when it is too high, the workability decreases.

Examples of the alkyl group of R ³ include lower alkyl groups such as methyl, ethyl, propyl and butyl.

  Examples of the divalent hydrocarbon group for X include alkylene groups such as methylene, ethylene and trimethylene; and phenylene. From the viewpoint of easiness of synthesis, X is preferably an oxy group or an ethylene group, particularly preferably an oxy group.

The monovalent hydrocarbon group for R ⁴ is an alkyl group such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, cycloalkyl group such as cyclohexyl group, Examples thereof include alkenyl groups such as vinyl group and allyl group; aryl groups such as phenyl group, tolyl group and xylyl group; and aralkyl groups such as 2-phenylethyl group and 2-phenylpropyl group. Further, as a halogenated hydrocarbon group, a chloromethyl group, a 3-chloropropyl group, a 3,3,3-trifluoropropyl group, etc. are exemplified, and as a cyanoalkyl group, a 2-cyanoethyl group, a 3-cyanopropyl group, etc. Can be mentioned. In terms of ease of synthesis, and the fact that the component (A1) has a viscosity that is relatively low for the molecular weight, and that both the workability of the composition and the good mechanical properties of the cured product are compatible, 85% of the entire R ⁴ It is preferable that the above is a methyl group, and it is more preferable that substantially all of R ⁴ is a methyl group.

In particular, in the case of imparting heat resistance, radiation resistance, cold resistance or transparency to a cured product, in the case of imparting oil resistance and solvent resistance to a required amount of phenyl groups as part of R ⁴ , when the 3,3,3-trifluoropropyl group or 3-cyanopropyl group as part of R ^4, also impart a surface with a coating aptitude, long-chain alkyl group or aralkyl as part of R ⁴ The structure of R ⁴ can be optionally selected according to the purpose, such as using a group in combination with a methyl group.

  The component (A1) is obtained by condensing the silanol group-terminated polyorganosiloxane and an excessive mole of tetraalkoxysilane relative to the silanol group of the polyorganosiloxane in the presence or absence of a catalyst. As the catalyst, known amines, carboxylic acids, metal carboxylates such as zinc, tin, iron and the like are used. If the condensation reaction is carried out in the absence of a catalyst, it is preferred to heat the reaction mixture to the reflux temperature of the tetraalkoxysilane. The molar ratio of tetraalkoxysilane / SiOH in the condensation reaction is preferably about 5-15.

  The component (A1) can also be obtained by adding a trialkoxysilane to a vinyl group-terminated polyorganosiloxane, or adding a vinyltrialkoxysilane to a hydrogen group-terminated polyorganosiloxane.

  The content of the component (A1) in the component (A) is 20 to 100% by mass with respect to the total amount of the component (A). When the content of the component (A1) is 20% by mass or more, the surface curability is good, and it is possible to suppress stains of the cured product, and excellent in storage stability, and mechanical of the cured product. The property is good. It is preferable that content of (A1) component is 40-80 mass% with respect to whole quantity of (A) component at the point which improves surface hardenability and the mechanical property of hardened | cured material.

  Adhesion is improved by blending both terminal trialkoxysilyl group-blocked polyorganosiloxane which is the component (A1), and mechanical properties such as hardness, tensile strength, elongation and adhesion of the cured product are improved. It can be improved.

  The component (A2) is, for example, an organopolysiloxane represented by the following general formula (A2).

In the above general formula representing the component (A2), R ⁵ is an alkyl group, and the same groups as the aforementioned R ³ can be mentioned. Furthermore, X is a divalent oxygen (oxy group) or a divalent hydrocarbon group, and the same groups as X in the general formula (A1) can be mentioned. R ⁶ is a group selected from a monovalent hydrocarbon group, a halogenated hydrocarbon group and a cyanoalkyl group, and is the same monovalent hydrocarbon group, a halogenated hydrocarbon group and a cyanoalkyl group as R ⁴ described above It can be mentioned. The plurality of R ^{5 's} , R ^{6' s} and X's may be the same as or different from one another.

  In the above general formula (A2), m represents the average polymerization degree of the (A2) both terminal dialkoxysilyl group-blocked polyorganosiloxane, and the viscosity at 23 ° C. is preferably 0.02 to 1000 Pa · s, more preferably 0 .1 to 500 Pa.s, which is a positive number. Specifically, m is preferably 20 to 2500, and more preferably 80 to 2000.

The average polymerization degrees n and m of the components (A1) and (A2) can be values estimated by the following equation using the weight (mass) average molecular weights of the components (A1) and (A2), respectively. .
n = weight-average molecular weight of component (A1) / (molecular weight of [SiOR ⁴ ₂ ] unit)
m = weight average molecular weight of component (A2) / (molecular weight of [SiOR ⁶ ₂ ] unit)

In addition, the weight average molecular weight (Mw) of (A1) component, (A2) component, and (C) component mentioned later is calculated | required by GPC (gel permeation chromatograph) on the basis of a polystyrene. The molecular weight of the [SiOR ⁴ ₂ ] unit and the molecular weight of the [SiOR ⁶ ₂ ] unit are both 74 when R ⁴ and R ⁶ are methyl groups.

  The viscosity at 23 ° C. of the component (A2) is preferably 0.02 to 1000 Pa · s, more preferably 0.1 to 500 Pa · s, as described above. The higher the viscosity of the component (A2), the better the surface curability. However, when the viscosity of the component (A2) is too low, the rubber elasticity after curing becomes poor, and when it is too high, the workability decreases.

  The component (A2) can be obtained in the same manner as the component (A1). That is, it can be obtained by using trialkoxysilane instead of tetraalkoxysilane and condensing with a silanol group-terminated polyorganosiloxane. The molar ratio of trialkoxysilane / SiOH in the condensation reaction is preferably about 5-15. Component (A2) can also be obtained by the same addition reaction as component (A1) using vinyl dialkoxysilane.

  Content of (A2) component in (A) component is 80-0 mass% with respect to the whole quantity of (A) component, and it is preferable that it is 60-20 mass%.

  The curing speed of the room temperature-curable polyorganosiloxane composition of the present invention and the hardness of the cured product can be controlled by blending the both terminal dialkoxysilyl group-blocked polyorganosiloxane which is the component (A2).

  In the room temperature curable polyorganosiloxane composition of this embodiment, the component (A) may contain components other than the components (A1) and (A2) as long as the effects of the present invention are not impaired. It is preferable to consist only of A1 component and (A2) component. As components other than the component (A1) and the component (A2) which can be contained in the component (A), terminal alkoxysilyl group-blocked polyorganosiloxane having a branch in the molecule, or terminal alkoxysilyl group having an alkoxy group in the molecular chain Blockade polyorganosiloxane and the like.

  The room temperature curable polyorganosiloxane composition of the present embodiment contains 1 to 100 parts by mass of the (B) inorganic filler. The inorganic filler of component (B) imparts mechanical strength to the cured product of the room temperature curable polyorganosiloxane composition. (B) As the inorganic filler, wet silica such as precipitated silica, dry silica such as fumed silica (fumed silica) or calcined silica, fine quartz powder, calcium carbonate, carbon black, diatomaceous earth, aluminum oxide, oxidized oxide Zinc, aluminosilicate, etc. can be used.

  From the viewpoint of the reinforcing property of the cured product, as the (B) inorganic filler, silica powder such as precipitated silica powder, fumed silica and the like are preferable. Moreover, it is preferable to mix | blend calcium carbonate as a (B) inorganic filler from the point which provides high mechanical strength to hardened | cured material.

As the silica powder, particularly, a silica powder having a specific surface area (hereinafter referred to as BET specific surface area) according to the BET method of 50 m ² / g or more, or its surface such as organochlorosilanes, polyorganosiloxanes, organosilazanes, etc. It is preferable to use one that has been surface-treated with a known treatment agent. The silica powder thus surface-treated imparts appropriate fluidity to the composition before curing, and imparts high mechanical strength required for the rubber-like elastic body obtained by curing depending on its application. can do.

  As calcium carbonate, for example, ground calcium carbonate or synthetic (light) calcium carbonate can be used. Calcium carbonate is a reinforcing filler, imparts high fluidity and consistency to the composition before curing, and imparts slump resistance and thixotropy. The particle size (average particle size) of calcium carbonate is preferably in the range of 0.01 to 10 μm. When the average particle size of calcium carbonate exceeds 10 μm, not only the mechanical properties of the cured product are degraded, but also the extensibility of the cured product is not sufficient. When the average particle size is less than 0.01 μm, the viscosity of the composition before curing is significantly increased and the flowability is reduced. The value of the average particle diameter is a value measured by image analysis with an electron microscope, an average particle diameter converted from a specific surface area, an average particle diameter determined from a 50% diameter by mass conversion from a particle size distribution, or It may be any of the average particle sizes measured by the laser diffraction / scattering method.

  In addition, the surface of such calcium carbonate is surfaced with higher fatty acids such as stearic acid and palmitic acid, resin (rosin) acids, or salts thereof (metal salts such as sodium salts, potassium salts, calcium salts) and esters. You may use what was processed. When calcium carbonate surface-treated with a higher fatty acid or an ester thereof is used, the dispersibility of calcium carbonate in the composition is improved, and the processability is improved.

  (B) When calcium carbonate is used as the inorganic filler, it is preferable to use light calcium carbonate and ground calcium carbonate in combination, and further, light calcium carbonate at this time is light calcium carbonate surface-treated as described above. Is more preferred. The hardness and adhesion of the cured product can be controlled by combining light calcium carbonate and ground calcium carbonate and adjusting their ratio.

  The blending amount of the inorganic filler which is the component (B) is not limited as long as the purpose of use of the composition is not impaired, and is usually 1 to 100 parts by mass with respect to 100 parts by mass of the component (A). When silica powder such as precipitated silica and fumed silica is blended, the blending amount is preferably 1 to 30 parts by weight, and 3 to 25 parts by weight with respect to 100 parts by weight of component (A). The range is particularly preferred. When the inorganic filler other than such silica powder, such as calcium carbonate, is blended, the blending amount is preferably 5 to 100 parts by mass with respect to 100 parts by mass of the component (A), The range of 30 to 70 parts by mass is more preferable, and about 40 to 60 parts by mass is more preferable. In any case, when the blending amount of the (B) inorganic filler is too large, the viscosity of the composition significantly increases and the workability in coating and the like becomes worse, and when too small, the mechanical strength of the cured product is sufficient. It may go away.

  (B) When light calcium carbonate and heavy calcium carbonate are used in combination as an inorganic filler, the weight ratio of light calcium carbonate to heavy calcium carbonate is that from the point of obtaining excellent mechanical properties, light calcium carbonate: heavy carbonate Preferred is 10: 0 to 5: 5 for calcium.

In the room temperature curable polyorganosiloxane composition of the present embodiment, the partial hydrolysis condensate of the alkoxysilane which is the (C) component is (C) a general formula: R ¹ _a Si (OR ² ) _4-a (wherein And R ¹ is a monovalent hydrocarbon group, R ² is an alkyl group or an alkoxy-substituted alkyl group, and a is 0, 1 or 2.) a partial hydrolytic condensate of an alkoxysilane represented by the formula:

In the above formula (C), R ¹ is a monovalent hydrocarbon group include the same groups as R ^4. R ² is an alkyl group or an alkoxy substituted alkyl group. Also, a is 0, 1 or 2.

  As the alkoxysilane, specifically, methyltrimethoxysilane, vinyltrimethoxysilane, decyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, methyltri (ethoxymethoxy) silane, tetramethoxysilane, tetraethoxysilane, Dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane and the like are exemplified.

  The partial hydrolysis condensate of the alkoxysilane which is the component (C) is a compound having a structure in which two or more molecules of the above-mentioned alkoxysilane are hydrolyzed and condensed via an alkoxy group. The average degree of polymerization of the (C) alkoxysilane partial hydrolytic condensate is preferably 3 to 50, more preferably 5 to 30, and still more preferably 7 to 15. (C) The degree of polymerization of the alkoxysilane partial hydrolytic condensate is 3 or more, so the deep-part curability is good, and by being 50 or less, with other essential components of the room-temperature curable polyorganosiloxane composition The workability is improved because of the excellent compatibility of

  (C) Alkoxysilane partial hydrolytic condensate is obtained, for example, by dropwise addition of aqueous hydrochloric acid to the above-mentioned alkoxysilane, heating to 60 to 80 ° C. to cause a condensation reaction, neutralization, and desolvation. The reaction time at this time is, for example, about 4 to 6 hours. Further, the average degree of polymerization of (C) alkoxysilane partial hydrolytic condensate is calculated from the weight average molecular weight of (C) alkoxysilane partial hydrolytic condensate, the formula: average degree of polymerization = weight average molecular weight / (alkoxysilane partial hydrolytic condensation The molecular weight of the polymerization unit of the product can be approximated as an approximation.

(C) Alkoxysilane partial hydrolytic condensate has a structure in which both are mixed, whether it is a structure in which an alkoxysilane monomer is linearly polymerized or a branched polymerization. It is also good. Although the structure of such a (C) alkoxysilane partial hydrolytic condensate can not necessarily be analyzed clearly, the average degree of polymerization becomes a value equal to or similar to the value estimated by the above equation. As such an approximate value, for example, when using a partial hydrolysis condensate obtained by partially hydrolytic condensation of methyltrimethoxysilane under the above conditions as the partial hydrolysis condensate of (C) alkoxysilane, the polymerization degree is obtained The weight average molecular weight of (C) methyltrimethoxysilane partial hydrolytic condensate can be estimated by (molecular weight of (CH ₃ (SiO) (OCH ₃ ) = 90). The average degree of polymerization of the (C) alkoxysilane partial hydrolytic condensate in the present embodiment may be within the preferable range of the approximation calculated by the above-mentioned formula.

  The room temperature-curable polyorganosiloxane of the present embodiment can improve surface curability and deep-part curability by including (C) alkoxysilane partial hydrolytic condensate. Therefore, it is difficult for unreacted components to remain in the cured product after curing, and it is possible to suppress bleeding from the cured product. In addition, excellent mechanical properties can be imparted to the cured product.

  The compounding quantity of (C) alkoxysilane partial hydrolysis condensation product is 0.5-15 mass parts with respect to 100 mass parts of (A) polyorganosiloxane mixture, and 1-10 mass parts is preferable. The amount of the (C) alkoxysilane partial hydrolytic condensate is 0.5 parts by mass or more, whereby a cured product with excellent mechanical strength can be obtained. By being 15 mass parts or less, it is excellent in deep part curability and it is easy to control a stain.

  In the embodiment of the present invention, as the titanium chelate catalyst which is the component (D), (diisopropoxybis (ethylacetoacetate) titanium, diisopropoxybis (methylacetoacetate) titanium, diisopropoxybis (acetalacetone) Well-known titanium chelate compounds, such as titanium, dibutoxy bis (ethyl aceto acetate) titanium, dimethoxy bis (ethyl aceto acetate) titanium, etc. are mentioned.

  The compounding amount of the (D) titanium chelate catalyst is 0.1 to 10 parts by mass, preferably 1 to 5 parts by mass with respect to 100 parts by mass of the (A) polyorganosiloxane mixture.

  In the embodiment of the present invention, the adhesiveness imparting agent which is the component (E) is a component which further enhances the adhesiveness and the adhesive durability of the composition.

  (E) As an adhesion imparting agent, it is also possible to use an isocyanurate compound such as 1,3,5-tris [isocyanuric acid 3- (trimethoxysilyl) propyl] represented by the following formula (3).

  (E) As an isocyanurate compound used as an adhesion imparting agent, a (trimethoxysilyl) propyl group bonded to the nitrogen atom of the above 1,3,5-tris [3- (trimethoxysilyl) propyl] isocyanuric acid compound The 1 or 2 may use the compound converted into 2-propenyl group or (dimethoxy silylmethyl) propyl group.

As the adhesion promoter (E), the general ^formula: silane compound represented by _{R 7} 4-q SiYq the like. 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. In addition, q is a number that exceeds 2 on average and 4 or less. Examples of R ⁷ include a substituted amino group, an epoxy group, an isocyanato group, a (meth) acryloxy group, a mercapto group, an alkyl group substituted with a halogen atom and a phenyl group. 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.

  (E) As a silane compound which has the said general formula which can be used as an adhesiveness imparting agent, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-aminopropyl triisopropoxysilane, 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-epoxycyclohexene Epoxy-containing silanes such as ethyltrimethoxysilane; 3-isocyanatopropyltrimethoxysilane; isocyanato-containing silanes such as 3-isocyanatopropylmethyldimethoxysilane; 3-acryloxypropyltrimethoxysilane, 3-methacrylic acid (Meth) acryloxy group-containing silanes such as roxypropyltrimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane; mercapto group-containing silanes such as 3-mercaptopropyltrimethoxysilane; and A halogen atom-containing silane such as 3-chloropropyltrimethoxysilane is exemplified. Among them, epoxy group-containing silanes and isocyanato group-containing silanes having less influence on the above-mentioned (D) titanium chelate catalyst are more preferable. Further, it is preferable to use a mixture or a reaction product of an amino group-containing silane and an epoxy group-containing silane.

  From the viewpoint of compatibility in the room temperature curable polyorganosiloxane composition, the amount of the component (E) is 0.01 to 5 parts by mass with respect to 100 parts by mass of the component (A). When the compounding amount of the component (E) is 0.01 or more with respect to 100 parts by mass of the component (A), a sufficient adhesive improvement effect can be obtained, and the expression thereof is also fast. Moreover, it can suppress that isolation | separation during storage and shrinkage | contraction of hardened | cured material arise because it is 5 mass parts or less, and generation | occurrence | production of the storage stability and workability fall, and yellowing phenomenon can be suppressed. The blending amount of the component (E) is preferably in the range of 0.1 to 2 parts by mass with respect to 100 parts by mass of the component (A).

  The room temperature-curable polyorganosiloxane composition of the present embodiment may be, as necessary, a thixotropy-imparting agent, a viscosity modifier, a flowability modifier, a pigment, a flame retardant, an organic solvent, an antifungal agent, an antibacterial agent, and an ultraviolet ray absorption. Various functional additives such as an agent, a heat resistance improver, etc. may be included.

  The room-temperature-curable polyorganosiloxane composition of this embodiment is generally non-crosslinkable, such as a dialkylpolysiloxane compounded for the purpose of adjusting the viscosity of the composition and imparting plasticity to a cured product, to the polyorganosiloxane composition. It is preferable not to contain substantially polyorganosiloxane of Moreover, it is preferable not to contain substantially alkoxysilanes (monomers), such as a methyl trimethoxysilane and a methyl triethoxysilane, mix | blended normally as a crosslinking agent to a polyorganosiloxane composition. By substantially not containing these non-crosslinkable polyorganosiloxanes and alkoxysilanes, the room temperature-curable polyorganosiloxane composition of the present embodiment can significantly suppress stains from the cured product. In addition, "does not substantially contain" unavoidably in the composition, for example, by being derived from these raw materials and impurities and contained together with each component of (A) to (E) which are essential components. It says that the said non-crosslinkable polyorganosiloxane and alkoxysilane are not mix | blended other than what is contained.

  The room temperature curable polyorganosiloxane composition of the present embodiment is a one-part type room temperature by uniformly mixing predetermined amounts of the components (A) to (E) and the other optional components described above in a dry atmosphere. It is obtained as a curable composition. When exposed to air, the composition undergoes a crosslinking reaction due to moisture and cures to a rubber elastic material. It can also be prepared as a two-part, room temperature curable composition. In the two-pack composition, the main agent and the curing agent are mixed in the air to cure in the same manner as the one-pack room temperature curable composition.

  And the room temperature curable polyorganosiloxane composition of embodiment is excellent in storage stability, and excellent in surface curability and deep part curability. In addition, the cured product obtained by curing the composition as described above is excellent in mechanical properties such as hardness, tensile strength, elongation, adhesiveness and the like.

  The room temperature curable polyorganosiloxane composition of the embodiment is excellent in surface curability and deep area curability, and the cured product thereof has excellent mechanical properties as described above. It is suitable as an adhesive and sealing agent in applications such as structures and civil engineering structures. In particular, because there is no stain from the cured product, it is suitable for applications where the appearance is important.

  As an application where such an appearance is emphasized, for example, an IH-like instrument will be described as an example. FIG. 1 is a cross-sectional view schematically showing the structure of the IH cooking apparatus 1. The IH cooker 1 includes, for example, an induction coil 10 and a glass or glass ceramic heat-resistant top plate 11 covering the upper side of the induction coil 10. On the top surface of the top plate 11, cooking equipment for IH, such as cooking pots for IH, frying pans for IH, frying pans for IH, etc., are placed. And the cooking appliance itself for IH is made to heat-generate by induction heating, and the to-be-cooked things, such as a meat piece in the cooking appliance for IH, and a vegetable piece, are cooked. The induction coil 10 is accommodated in a housing 12 made of a nonmagnetic metal plate such as nonmagnetic stainless steel or aluminum.

  In the IH tuning instrument 1, the top plate 11 is bonded via the adhesive resin 13 onto the surface of the metal plate 12 a above the induction coil 10, which constitutes the housing 12. On the lower surface 11a of the top plate 11 opposite to the upper surface on which the IH cookware is placed, a colored coating made of a noble metal coating or a colored glass coating is provided for the purpose of improving design and the like. May be applied.

  Here, when a cured product of a conventional room temperature curable polyorganosiloxane composition is used as the adhesive resin 13, stains from the cured product may adhere to the colored coating and infiltrate into the inside. In this case, this stain is visible from above the top rate, and the appearance is impaired. On the other hand, according to the room temperature curable polyorganosiloxane composition of the present embodiment, since the stains from the cured product are significantly suppressed, the appearance of the top plate of the IH cooker as described above can be improved. it can.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following examples and comparative examples, "parts" indicates parts by mass, and the viscosity is a value at 23 ° C.

Each component used in the following Examples and Comparative Examples is as follows.
A1-1: Polydimethylsiloxane blocked at both ends with a trimethoxysilyl group (viscosity 22 Pa · s, average polymerization degree 1020)
A2-1: Polydimethylsiloxane blocked at both ends with methyldimethoxysilyl group (viscosity 11 Pa · s, average degree of polymerization 820)
A3: Polydimethylsiloxane blocked at both ends with a trimethylsilyl group (viscosity: 0.1 Pa · s, average polymerization degree 90)

B1: Light calcium carbonate surface-treated with fatty acid (stearic acid) (average particle size: 0.05 μm)
B2: unprocessed ground calcium carbonate (average particle size: 2.2 μm)
B3: Dry silica (specific surface area by BET method: 130 m ² / g)

C1: Partially hydrolyzed condensate of methyltrimethoxysilane (average degree of polymerization: 7 (heptamer))
C2: methyltrimethoxysilane

D: Diisopropoxybis (ethylacetoacetate) titanium E: 1,3,5-trisocyanate [3- (trimethoxysilyl) propyl]

(C1: Preparation of partial hydrolytic condensate of methyltrimethoxysilane)
The partial hydrolytic condensate of (C1) methyltrimethoxysilane was prepared as follows. Hydrochloric acid water was added dropwise to methyltrimethoxysilane, heated to 70 ° C., and stirred for about 5 hours to cause condensation reaction. Then, neutralization and desolvation were performed to obtain a partial hydrolytic condensate of (C1) methyltrimethoxysilane. The approximate value of the average degree of polymerization of the obtained partially hydrolyzed condensate of (C1) methyltrimethoxysilane was approximated by the weight average molecular weight / 90 of the partially hydrolyzed condensate of (C1) methyltrimethoxysilane.

Example 1
(A1-1) 80 parts by mass of polydimethylsiloxane (viscosity 22 Pa · s, average degree of polymerization 1020) blocked at both ends with a trimethoxysilyl group, and (A2-1) both ends blocked with a methyldimethoxysilyl group 20 parts by mass of the polydimethylsiloxane (viscosity 11 Pa · s, average degree of polymerization 820) was mixed to prepare 100 parts by mass of a polyorganosiloxane mixture. In 100 parts by mass of this polyorganosiloxane mixture, 45 parts by mass of light calcium carbonate surface-treated with fatty acid (B1), 5 parts by mass of untreated heavy calcium carbonate (B2), partial hydrolysis of (C1) methyltrimethoxysilane 3.5 parts by mass of decomposition condensate (average degree of polymerization: 7), 1.0 parts by mass of (D) diisopropoxy bis (ethylacetoacetate) titanium, (E) 1,3,5-trisocyanate of isocyanuric acid [3- 0.5 parts by mass of (trimethoxysilyl) propyl] was mixed to obtain a polyorganosiloxane composition.

(Examples 2 to 7, Comparative Examples 1 to 3)
The types and blending amounts of the components (A) to (E) were changed as shown in Table 1 to obtain polyorganosiloxane compositions of Examples 2 to 7 and Comparative Examples 1 to 3.

  Next, with regard to the polyorganosiloxane compositions obtained in the above Examples and Comparative Examples, the tack free time and hardness of the cured product, tensile strength, elongation, shear adhesion, deep-part curability, and stain resistance are described below. It measured and evaluated by the method of The results of these measurements and evaluations are shown in the lower column of Table 1.

[Tack free time]
The polyorganosiloxane composition is applied to the surface of an aluminum petri dish having a diameter of 5 cm, the surface of which has been washed with an organic solvent, and brought into contact with the surface and dried in an environment of 23 ° C. and 50% relative humidity (RH). The time taken to confirm the presence was measured.

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

[Shear adhesion]
The composition was applied on the surface of an aluminum substrate to a length of 10 mm, a width of 25 mm, and a thickness of 1 mm, and was left in an atmosphere of 23 ° C. and 50% RH for 7 days to be cured.
And about the obtained test piece, the tension test was done by Shimadzu Corporation autograph by tension rate 10 mm / min, and shear adhesion was measured.

Deep cure
The composition was sealed in a polystyrene cup (15 ml), and the top was smoothed and then left to cure for 7 days in an atmosphere of 23 ° C. and 50% RH. And about the obtained test piece, the hardened | cured part was taken out and the thickness was measured with the thickness measuring device. The thicker the cured part is, the better the deep part curing property.

[Staining test]
1 g of the composition is applied to the printed surface (surface having a colored coating) of printed glass (100 mm × 100 mm, thickness 4 mm) having a colored coating on one main surface, and the thickness of the composition is 1 mm The substrate was loaded and allowed to cure for 2 hours in an atmosphere of 40 ° C. and 50% RH. Then, the obtained test piece was left in an atmosphere of 90 ° C. and 90% RH for 4 hours, and the presence or absence of a stain was visually confirmed from the surface on the opposite side of the printed surface.

<Storage stability test (characteristics after acceleration of heat deterioration)>
The composition is put in a container protected from moisture and heated at 70 ° C. for 5 days for deterioration, and then the tack free time, hardness, tensile strength, elongation, shear adhesion and deep part curability are measured in the same manner as above. did.

  As shown in Table 1, room temperature curing of the present invention comprising (C) an alkoxysilane partial hydrolytic condensate as a crosslinking agent in (A) polyorganosiloxane mixture and (D) a titanium chelate catalyst as a curing catalyst Polyorganosiloxane composition is excellent in surface curability and deep curability. Furthermore, since it contains (B) an inorganic filler and (E) an adhesion imparting agent, a cured product having excellent mechanical properties such as hardness, tensile strength, elongation and shear adhesion can be produced. Moreover, since it is excellent in storage stability, the fall of surface-hardening property and deep-parts hardenability, and the fall of the mechanical property of hardened | cured material are very small also after storage.

  Furthermore, since the exudation from the cured product obtained by the composition having excellent surface curability and deep curability is remarkably suppressed, the curing of the room temperature curable polyorganosiloxane composition of the present invention is carried out on the surface of the glass substrate. When an article is formed, a laminate excellent in appearance can be obtained.

  DESCRIPTION OF SYMBOLS 1 ... IH cooking appliance, 11 ... top plate, 12 ... housing | casing, 12a ... metal plate, 13 ... adhesive resin.

Claims (7)

(A) (A1) 20 to 100% by mass of a linear polyorganosiloxane blocked at both ends with a trialkoxysilyl group and (A2) a linear poly blocked at both ends with a dialkoxysilyl group 100 parts by weight of a polyorganosiloxane mixture consisting of a mixture of 80 to 0% by weight of organosiloxanes,
(B) 1 to 100 parts by mass of the inorganic filler,
(C) General formula: R ¹ _a Si (OR ² ) _4-a
(Wherein, R ¹ is a monovalent hydrocarbon group, R ² is an alkyl group or an alkoxy-substituted alkyl group, and a is 0, 1 or 2)
0.5 to 15 parts by mass of the partially hydrolyzed condensate of alkoxysilane represented by
A room temperature curable polyorganosiloxane composition comprising (D) 0.1 to 10 parts by mass of a titanium chelate catalyst and (E) 0.01 to 5 parts by mass of an adhesion promoter.   The room temperature curable polyorganosiloxane composition according to claim 1, wherein the (B) inorganic filler comprises calcium carbonate or silica powder.   The room temperature curable polyorganosiloxane composition according to claim 2, wherein the calcium carbonate comprises at least one selected from ground calcium carbonate and light calcium carbonate.   The room temperature-curable polyorganosiloxane composition according to any one of claims 1 to 3, wherein the average degree of polymerization of the partially hydrolyzed condensate of (C) alkoxysilane is 3 to 50.   A cured product obtained by curing the room temperature curable polyorganosiloxane composition according to any one of claims 1 to 4. A laminate comprising a metal base, an adhesive resin disposed on the surface of the metal base, and a heat-resistant plate made of glass or glass ceramic disposed on the surface of the adhesive resin,
The said adhesive resin is a laminated body which consists of hardened | cured material of Claim 5.   The laminate according to claim 6, wherein a colored coating is provided on the main surface on the adhesive resin side of the heat-resistant plate.

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