Curable polyorganosiloxane composition and cured product thereof, protective agent or adhesive and electrical / electronic device

Abstract

Provided is a curable polyorganosiloxane composition which has excellent storage stability in the form of a single liquid, has good curability and adhesiveness even at relatively low temperatures, and has an appropriate usable time. Specifically, provided is a curable polyorganosiloxane composition which has excellent curability even at a temperature of 80 DEG C or less and which has excellent adhesion to resins such as polyesters and polyphenylene sulfide. A one-pack type curable polyorganosiloxane composition comprising the following components (A) to (E): (A) a polyorganosiloxane having at least two alkenyl groups in one molecule; (B) a polyorganosiloxane having at least two silicon atoms bonded to hydrogen atoms in one molecule; (C) a hydrosilylation reaction catalyst; (D) a condensation reaction catalyst selected from the group consisting of titanium tetra-tert-butoxy, titanium bis (isopropoxy) bis (ethyl acetoacetate), and a chelate aluminum complex, or a condensation reaction product thereof; and (E) a curing inhibitor. The silicone rubber composition having a JIS A hardness of 5 or more is provided by curing. The composition may optionally contain a large amount of (H) an inorganic filler or the like.

Description

Technical Field

[0001] The present invention relates to a curable polyorganosiloxane composition, a cured product thereof, a protective agent or an adhesive, and an electric / electronic device. Background Art

[0002] Curable polyorganosiloxane compositions are widely used as protective agents or adhesives for electric / electronic components. As protective agents or adhesives for electric / electronic components, excellent reliability and durability are important. In particular, when contacting a substrate before complete curing, excellent self-adhesiveness is required. In recent years, miniaturization, multi-functionality, and light-weighting of electric / electronic components have been promoted, and the shapes of electric / electronic components have become more complex in accordance with the uses. Therefore, curable polyorganosiloxanes are sometimes used in different protective or adhesive methods such as bonding in small amounts and bonding in a thin film form, which are different from the past.

[0003] Patent Document 1 discloses a composition which is a curable polyorganosiloxane capable of bonding well to an uncleaned aluminum die-cast, PPS resin, etc., and contains a specific polyorganosiloxane containing an alkoxysilyl group and an alkenyl group. However, the composition disclosed in Patent Document 1 cannot be cured unless heated to about 100°C. In addition, depending on the substrate, excellent adhesiveness may not be obtained. Moreover, when used as an adhesive in the form of a thin film, sufficient initial adhesiveness and adhesive strength may not be obtained.

[0004] In order to provide a curable polyorganosiloxane composition having lower temperature curability and excellent self-adhesiveness, Patent Document 2 discloses a curable polyorganosiloxane composition which simultaneously uses a catalyst for hydrosilylation reaction and a catalyst for condensation reaction, and contains a specific siloxane containing a trialkoxysilyl group. However, since the composition disclosed in Patent Document 2 is a two-component type, it is necessary to mix the two components before use. In addition, the pot life after mixing is short, and there are problems with operability and stability.

[0005] Patent Document 3 discloses a self-adhesive silicone rubber composition which contains a platinum-based catalyst and a specific titanium compound and / or its partial hydrolysis condensate. However, since the composition disclosed in Patent Document 3 is in a gel form, sufficient adhesive force cannot be obtained when used for electric / electronic components, and it cannot be used for applications requiring the properties of an elastomer. In addition, Patent Document 4 discloses a curable polyorganosiloxane composition which simultaneously uses a catalyst for hydrosilylation reaction and a catalyst for condensation reaction, and contains a silanol-modified siloxane and alkoxysilanes as crosslinking agents, but its main component is not a polyorganosiloxane containing an alkenyl group, and it will not be sufficiently cured in a short time unless at a high temperature of 120°C or higher, and the adhesiveness to the substrate is also insufficient.

[0006] Prior art documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Laid-Open No. 2006-348119

[0009] Patent Document 2: International Publication No. 2018 / 043270

[0010] Patent Document 3: Japanese Patent Laid-Open No. 2018-119021

[0011] Patent Document 4: U.S. Patent Application Publication No. 2014 / 0356620 Summary of the invention

[0012] Problems to be solved by the invention

[0013] The present invention has been completed in order to solve the above problems of the prior art, and an object thereof is to provide a curable polyorganosiloxane composition having excellent storage stability in a single-component form, having good curability even at relatively low temperatures and practically sufficient adhesiveness, and having an appropriate pot life. Another object of the present invention is to provide a curable polyorganosiloxane composition, particularly, having excellent curability even at temperatures of 80°C or lower, and having excellent adhesiveness during low-temperature curing to resins with poor adhesiveness such as polycarbonate and polyphenylene sulfide and metal substrates.

[0014] Furthermore, an object of the present invention is to provide a protective agent or adhesive containing the above curable polyorganosiloxane composition, a cured product thereof, and an electrical / electronic device. In particular, an object of the present invention is to provide an electrical / electronic component having excellent reliability and durability by using the curable polyorganosiloxane composition of the present invention, thereby providing an excellent electrical / electronic device.

[0015] Solutions for solving the problems

[0016] The present inventors have conducted in-depth research on the above technical problems, and as a result, the present invention has been achieved. That is, the object of the present invention is achieved by a one-component curable polyorganosiloxane composition containing the following components (A) to (E):

[0017] (A) A polyorganosiloxane having at least two alkenyl groups in one molecule;

[0018] (B) A polyorganosiloxane having at least two silicon-bonded hydrogen atoms in one molecule;

[0019] (C) A catalyst for hydrosilylation reaction;

[0020] (D) A catalyst for condensation reaction selected from the group consisting of titanium tetra-tert-butoxide, bis(isopropoxy)bis(ethyl acetoacetate)titanium, and chelated aluminum complex, or a condensation reaction product thereof; and

[0021] (E) A curing inhibitor,

[0022] A silicone rubber composition having a JIS A hardness of 5 or more is provided by curing.

[0023] Preferably, the component (B) is contained in an amount such that the molar ratio of the silicon atom-bonded hydrogen atom to the alkenyl group in all components of the curable polyorganosiloxane composition is in the range of 0.3 to 10.

[0024] Preferably, the content of the component (D) is 0.5% by mass or less based on the total mass of the curable polyorganosiloxane composition. It should be noted that bis(isopropoxy)bis(ethyl acetoacetate)titanium has the advantage that a preferable effect can be achieved even in an amount of less than 0.1% by mass.

[0025] Preferably, the content of the compound having a carbon-carbon triple bond in the molecule in the component (E) is 0.001 to 0.5% by mass based on the total mass of the curable polyorganosiloxane composition.

[0026] The curable polyorganosiloxane composition of the present invention may further contain:

[0027] (F) A trialkoxysilyl group-containing siloxane having one silicon atom-bonded hydrogen atom in one molecule,

[0028] and having at least one trialkoxysilyl group.

[0029] Preferably, the component (F) is a trialkoxysilyl group-containing siloxane represented by the following formula:

[0030] [Chemical formula 1]

[0031]

[0032] (In the formula, R 1 are the same or different monovalent hydrocarbon groups having no aliphatic unsaturated bond, R 2 is an alkyl group, R 3 is an alkylene group, and p is an integer of 1 to 50).

[0033] Preferably, the content of the component (F) is 0.05 to 10% by mass based on the total mass of the curable polyorganosiloxane composition.

[0034] The curable polyorganosiloxane composition of the present invention may further contain:

[0035] (G) Adhesion promoter.

[0036] The curable polyorganosiloxane composition of the present invention may further comprise:

[0037] (H) Inorganic filler.

[0038] In particular, it may contain a conductive filler, and silver particles or alumina or glass fine particles coated with silver may preferably be used.

[0039] Preferably, the curable polyorganosiloxane composition of the present invention can be cured at a temperature of 80°C or lower.

[0040] The present invention also relates to a protective agent or adhesive for electrical / electronic components containing the curable polyorganosiloxane composition of the present invention.

[0041] The present invention also relates to a curable composition having conductivity or heat conductivity containing the curable polyorganosiloxane composition of the present invention.

[0042] In addition, the present invention also relates to a cured product of the curable polyorganosiloxane composition of the present invention.

[0043] In addition, the present invention also relates to an electrical / electronic device having the cured product of the present invention.

[0044] In addition, the present invention also relates to an electrical / electronic device in which electrical / electronic components are bonded, encapsulated or sealed with the curable polyorganosiloxane composition of the present invention.

[0045] Advantages of the Invention

[0046] According to the curable polyorganosiloxane composition of the present invention, even when stored in a single-component form, the storage stability is excellent, and it is easily cured even at a relatively low temperature of 80°C or lower and can exhibit excellent adhesiveness. In particular, even under low-temperature curing conditions, it exhibits excellent adhesiveness to resins with poor adhesiveness such as polycarbonate and polyphenylene sulfide and metal substrates such as aluminum. Moreover, even when a large amount of inorganic filler (in particular, conductive filler such as silver) is incorporated, it exhibits excellent adhesiveness to resins and metal substrates.

[0047] In addition, by using the curable polyorganosiloxane composition of the present invention, the reliability and durability of electrical / electronic components can be maintained for a long time, and excellent adhesiveness can be exhibited. In addition, the curable polyorganosiloxane composition of the present invention can be used as a heat-conductive material or a conductive material having excellent adhesion to a substrate. Detailed Embodiments

[0048] The curable polyorganosiloxane composition of the present invention is a one-component curable polyorganosiloxane composition, and the one-component curable polyorganosiloxane composition contains the following components (A) to (E):

[0049] (A) A polyorganosiloxane having at least two alkenyl groups in one molecule;

[0050] (B) A polyorganosiloxane having at least two silicon-bonded hydrogen atoms in one molecule;

[0051] (C) A catalyst for hydrosilylation reaction;

[0052] (D) A catalyst for condensation reaction or its condensation reaction product selected from the group consisting of tetra-tert-butoxytitanium, bis(isopropoxy)bis(ethyl acetoacetate)titanium, and chelated aluminum complex; and

[0053] (E) A curing inhibitor,

[0054] A silicone rubber composition having a JIS A hardness of 5 or more is provided by curing.

[0055] [Component (A)]

[0056] Component (A) is the main component of the composition of the present invention, and it is a polyorganosiloxane having at least two alkenyl groups in one molecule. Such component (A) is composed of one or more alkenyl-containing polyorganosiloxanes. Component (A) is preferably a polyorganosiloxane having at least two alkenyl groups in one molecule and not having a group containing an alkoxysilyl group described later in the molecule. In addition, preferably, component (A) is not pre-reacted with component (F) described later and is added to the composition.

[0057] (A) The molecular structure of the component is not particularly limited. For example, linear, branched, cyclic, three-dimensional network structures, and combinations thereof can be cited. In addition, as the alkenyl group bonded to the silicon atom in the component (A), vinyl, allyl, butenyl, pentenyl, and hexenyl are exemplified, and vinyl or hexenyl is particularly preferred. The bonding position of the alkenyl group is not particularly limited, but the molecular chain end and / or the molecular chain side chain are exemplified. In addition, as the group bonded to the silicon atom other than the alkenyl group in the component (A), substituted or unsubstituted monovalent hydrocarbon groups such as alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; and halogenated alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl are exemplified, and methyl or phenyl is particularly preferred. The component (A) may also be a mixture of two or more having these molecular structures. Particularly preferably, the molecular structure of the component (A) is chain-like (including linear and branched) or resin-like. In addition, the viscosity of the component (A) at 25 °C is not particularly limited. For example, it is preferably in the range of 20 to 1,000,000 mPa·s, and particularly preferably in the range of 100 to 100,000 mPa·s. This is because when the viscosity at 25 °C is less than the lower limit of the above range, the physical properties of the obtained cured product, particularly flexibility and elongation, may sometimes be significantly reduced. On the other hand, when the viscosity at 25 °C exceeds the upper limit of the above range, the viscosity of the obtained composition becomes high, and the operation workability may sometimes deteriorate significantly.

[0058] As such a chain-like polyorganosiloxane in the component (A), examples include: dimethylsiloxane / methylvinylsiloxane copolymer capped at both molecular chain ends with trimethylsiloxy groups, dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer capped at both molecular chain ends with trimethylsiloxy groups, dimethylpolysiloxane capped at both molecular chain ends with dimethylvinylsiloxy groups, methylphenylpolysiloxane capped at both molecular chain ends with dimethylvinylsiloxy groups, dimethylsiloxane / methylvinylsiloxane copolymer capped at both molecular chain ends with dimethylvinylsiloxy groups, dimethylsiloxane / methylvinylsiloxane copolymer capped at both molecular chain ends with dimethylphenylsiloxy groups, dimethylsiloxane / methylvinylsiloxane / diphenylsiloxane copolymer capped at both molecular chain ends with trimethylsiloxy groups, dimethylpolysiloxane / diphenylsiloxane copolymer capped at both molecular chain ends with dimethylvinylsiloxy groups;

[0059] and dimethylpolysiloxane capped at both molecular chain ends with methylvinylphenylsiloxy groups.

[0060] As the resinous polyorganosiloxane in the component (A), polyorganosiloxanes having a plurality of T units or Q units as branched siloxane units are exemplified. For example, MQ resins, MDQ resins, MTQ resins, MDTQ resins, TD resins, TQ resins, and TDQ resins formed by any combination of triorganosiloxy units (M units) (the organic group is a group selected from alkyl groups such as methyl, aryl groups such as phenyl, and alkenyl groups such as vinyl, the same applies hereinafter), diorganosiloxy units (D units) (the organic group is a group selected from alkyl groups, aryl groups, and alkenyl groups), monoorganosiloxy units (T units) (the organic group is a group selected from alkyl groups, aryl groups, and alkenyl groups), and siloxy units (Q units) are exemplified. It should be noted that the component (A) has at least two alkenyl groups in the molecule and may contain silanol groups or alkoxy groups in addition to the above-mentioned siloxane units.

[0061] [Component (B)]

[0062] The component (B) is a polyorganosiloxane having at least two silicon atom-bonded hydrogen atoms in one molecule and is a crosslinking agent for the composition of the present invention. The component (B) reacts with the component (A) to form a crosslinked structure in the cured product, enabling the cured product to achieve flexibility, strength, and strong adhesion (adhesion durability) to the substrate.

[0063] As the molecular structure of the component (B), for example, linear, partially branched linear, branched, cyclic, three-dimensional network structures, and combinations thereof are exemplified. In addition, as the bonding position of the hydrogen atom bonded to the silicon atom in the component (B), the molecular chain end and / or the molecular chain side chain are exemplified. In addition, as the group bonded to the silicon atom in the component (B) other than the hydrogen atom, for example, alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; and substituted or unsubstituted monovalent hydrocarbon groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl are exemplified, and methyl or phenyl is particularly preferred. In addition, the viscosity of the component (B) is not limited, and the viscosity at 25 °C is in the range of 1 to 1000 mPa·s, preferably in the range of 1 to 500 mPa·s. Moreover, from the viewpoint of preventing contact failures, etc., low molecular weight siloxane oligomers (octamethyltetrasiloxane, decamethylpentasiloxane) can be reduced or removed.

[0064] As the linear (B) component, examples include: dimethylpolysiloxane capped at both molecular chain ends with dimethylhydroxysilyloxy, methylphenylpolysiloxane capped at both molecular chain ends with dimethylhydroxysilyloxy, dimethylsiloxane / methylphenylsiloxane copolymer capped at both molecular chain ends with dimethylhydroxysilyloxy, diphenylpolysiloxane capped at both molecular chain ends with dimethylhydroxysilyloxy, methylhydrogenpolysiloxane capped at both molecular chain ends with trimethylsilyloxy, methylhydrogen siloxane / dimethylsiloxane copolymer capped at both molecular chain ends with trimethylsilyloxy, methylhydrogen siloxane / dimethylsiloxane copolymer capped at both molecular chain ends with dimethylhydroxysilyloxy, and mixtures of two or more of these polyorganosiloxanes.

[0065] The cyclic (B) component is composed of diorganosiloxane units and is a polysiloxane having at least two methylhydroxysiloxane units (CH 3 (H)SiO 2 / 2 ). Preferably, examples include: cyclic trisiloxane (trimer), cyclic tetrasiloxane (tetramer), and cyclic pentasiloxane (pentamer). These cyclic siloxanes can be cyclic siloxanes containing one or two or more of the following selected units as other diorganosiloxane units: alkoxymethylsiloxane unit (CH 3 (Alkoxy)SiO 2 / 2 ), epoxy methylsiloxane unit (CH 3 (Epoxy)SiO 2 / 2 ), dimethylsiloxane unit ((CH 3 ) 2 SiO 2 / 2 ), diphenylsiloxane unit ((C 6 H 5 ) 2 SiO 2 / 2 ), and phenylmethylsiloxane unit ((C 6 H 5 )(CH 3 )SiO 2 / 2 ).

[0066] The resinous or three-dimensional network (B) component can be, for example, an organohydrogenpolysiloxane represented by the following average compositional formula.

[0067] (HR 2 SiO 1 / 2 ) e (R 3 SiO 1 / 2 ) f (HRSiO 2 / 2 ) g (R 2 SiO2 / 2 ) h (HSiO 3 / 2 ) i (RSiO 3 / 2 ) j (SiO 4 / 2 ) k (R'O 1 / 2 ) l

[0068] In the above average compositional formula, R is a group selected from monovalent saturated hydrocarbon groups having 1 to 12 carbon atoms without aliphatic unsaturated bonds, hydroxyl groups, and alkoxy groups. Regarding the monovalent saturated hydrocarbon groups having 1 to 12 carbon atoms, hydroxyl groups, and alkoxy groups, it is the same as above. R' is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, propyl, butyl, and hexyl. e, f, g, h, i, j, k, and l are numbers satisfying the following conditions: e + f + g + h + i + j + k = 1, 0 ≤ l ≤ 0.1, and 0 < i + j + k ≤ 1.0.

[0069] It should be noted that the "HR 2 SiO 1 / 2 ", "R 3 SiO 1 / 2 ", "HRSiO 2 / 2 ", "R 2 SiO 2 / 2 ", "HSiO 3 / 2 ", "RSiO 3 / 2 ", and "SiO 4 / 2 " structural units are respectively called M H unit, M unit, D H unit, D unit, T H unit, T unit, Q unit, which are partial structural units of organohydrogenpolysiloxane. The resinous or three-dimensional network (B) component contains in the molecule: branched units selected from TH unit, T unit, and Q unit. "R'O 1 / 2 " is a group bonded to the oxygen atom in D unit, DH unit, T unit, T H unit or Q unit, and refers to the hydroxyl group bonded to the silicon atom (Si―OH) in the polyorganosiloxane or the alkoxy group bonded to the silicon atom remaining unreacted during the production of the polyorganosiloxane. M H unit mainly exists at the molecular chain ends of the organohydrogenpolysiloxane, and D H unit exists in the molecular chain of the organohydrogenpolysiloxane.

[0070] Practically, as the resinous or three-dimensional network (B) component, preferably, examples include:

[0071] · composed of MH An organohydrogenpolysiloxane resin composed of T units, M units and Q units

[0072] · An organohydrogenpolysiloxane resin composed of M H units and / or M units, D H units and Q units

[0073] · An organohydrogenpolysiloxane resin composed of M H units and / or M units, D units and Q units

[0074] · An organohydrogenpolysiloxane resin composed of T H units.

[0075] It should be noted that these organohydrogenpolysiloxane resins may contain a small amount of other structural units.

[0076] More specifically, examples of the resinous or three-dimensional network (B) component include:

[0077] An organohydrogenpolysiloxane resin composed of (CH 3 ) 2 HSiO 1 / 2 units and SiO 4 / 2 units;

[0078] An organohydrogenpolysiloxane resin composed of (CH 3 ) 3 SiO 1 / 2 units and (CH 3 )HSiO 2 / 2 units and SiO 4 / 2 units;

[0079] An organohydrogenpolysiloxane resin composed of (CH 3 ) 2 HSiO 1 / 2 units, (CH 3 ) 2 SiO 2 / 2 units SiO 4 / 2 units; and

[0080] An organohydrogenpolysiloxane resin composed of (CH 3 ) 2 HSiO 1 / 2 units, SiO 4 / 2 units and (C 6 H 5 )SiO 3 / 2 units;

[0081] Optionally containing (CH 3 ) 2 HSiO1 / 2 unit or (CH 3 ) 3 SiO 1 / 2 unit, an organohydrogenpolysiloxane resin essentially composed of HSiO 3 / 2 units.

[0082] As the component (B), preferably, a linear polyorganosiloxane having at least three silicon atoms bonded to hydrogen atoms in one molecule, since it has many crosslinking reaction points, can densely form a three-dimensional crosslinked structure with the component (A) in the curing reaction of the curable polyorganosiloxane composition of the present invention. Particularly preferably, a methylhydrogenpolysiloxane capped with trimethylsiloxy groups at both ends of the molecular chain is used.

[0083] With respect to one alkenyl group in all the components of the curable polyorganosiloxane composition, the content of the component (B) is an amount in the range of 0.3 to 10 silicon atoms bonded to hydrogen atoms, preferably an amount in the range of 0.5 to 3.0, and more preferably an amount of 0.8 to 2.0. The reason is that when the number of the above-mentioned silicon atoms bonded to hydrogen atoms is less than the lower limit of the above range, the obtained composition is not sufficiently cured. On the other hand, when it exceeds the upper limit of the above range, hydrogen gas is generated during the curing process of the obtained composition, or the heat resistance of the obtained cured product sometimes significantly decreases.

[0084] In the curable polyorganosiloxane composition of the present invention, the content of the component (B) with respect to 100 parts by mass of the component (A) is 0.1 to 30 parts by mass, preferably 0.2 to 20 parts by mass, and more preferably 0.5 to 10 parts by mass. This is because when the component (B) is less than the lower limit of the above range, the adhesiveness of the film of the obtained composition is insufficient. On the other hand, when it exceeds the upper limit of the above range, the elastic modulus of the composition decreases, and there is a tendency for the adhesive strength to significantly decrease even in the case of cohesive failure. In addition, when the component (B) is less than the lower limit of the above range, the obtained composition has a tendency to be not sufficiently cured, and when it exceeds the upper limit of the above range, the obtained composition sometimes generates hydrogen gas during the curing process and causes foaming.

[0085] [Component (C) and Component (D)]

[0086] The curable polyorganosiloxane composition of the present invention, in addition to the above-mentioned components (A) and (B), further contains two different curing catalysts: (C) a catalyst for hydrosilylation reaction; and (D) a catalyst for condensation reaction or a condensation reaction product selected from the group consisting of tetra-tert-butoxytitanium, bis(isopropoxy)bis(ethyl acetoacetate)titanium, and chelated aluminum complex. By using the two catalysts in combination with the above-mentioned respective components, the technical effects of being easily curable by heating at room temperature to 80°C or below and having excellent adhesiveness to various substrates are achieved.

[0087] The component (C) is a catalyst for hydrosilylation reaction that exhibits activity in the composition, and is a component for promoting the hydrosilylation reaction to cure the curable polyorganosiloxane composition of the present invention. Such a component (C) preferably contains a catalyst that promotes the hydrosilylation reaction without the irradiation of high-energy rays, but may also be used in combination with a photoactive hydrosilylation reaction catalyst that promotes the hydrosilylation reaction by the irradiation of high-energy rays as needed.

[0088] Examples of preferred hydrosilylation reaction catalysts include: platinum-based catalysts, rhodium-based catalysts, palladium-based catalysts, nickel-based catalysts, iridium-based catalysts, ruthenium-based catalysts, and iron-based catalysts, with platinum-based catalysts being preferred. Examples of such platinum-based catalysts include: platinum micropowder, platinum black, silica micropowder loaded with platinum, activated carbon loaded with platinum, chloroplatinic acid, an alcoholic solution of chloroplatinic acid, platinum olefin complexes, platinum vinylsiloxane complexes and other platinum-based compounds, with platinum vinylsiloxane complexes being particularly preferred. Examples of such vinylsiloxanes include: 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, vinylsiloxanes in which a part of the methyl groups of these vinylsiloxanes are substituted by ethyl, phenyl, etc., and vinylsiloxanes in which the vinyl groups of these vinylsiloxanes are substituted by allyl, hexenyl, etc. In particular, since the platinum-vinylsiloxane complex has good stability, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane is preferred. In addition, since the stability of the platinum-vinylsiloxane complex can be improved, it is preferred to add vinylsiloxanes such as 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, 1,3-diallyl-1,1,3,3-tetramethyldisiloxane, 1,3-divinyl-1,3-dimethyl-1,3-diphenyldisiloxane, 1,3-divinyl-1,1,3,3-tetraphenyldisiloxane, and 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, and organosiloxane oligomers such as dimethylsiloxane oligomers, with vinylsiloxanes being particularly preferred. In addition, as other platinum-based catalysts, thermoplastic resin particles containing platinum-based catalysts are exemplified.

[0089] The hydrosilylation reaction catalyst herein is preferably a catalyst that exhibits activity without the irradiation of high-energy rays, and among them, a catalyst that exhibits activity even at a relatively low temperature is preferred. Specifically, a catalyst that exhibits activity in the composition in the temperature range of 0 to 200 °C, preferably in the temperature range of 40 to 100 °C or lower, and promotes the hydrosilylation reaction is preferred.

[0090] (C) The content of the component is a catalytic amount that varies depending on the type of catalyst and the type of composition. However, generally, for the curable polyorganosiloxane composition, the metal atoms in this catalyst are preferably in the range of 0.01 ppm to 100 ppm, more preferably in the range of 0.1 ppm to 50 ppm, in terms of mass unit.

[0091] (D) By using the component in combination with the (C) component, the curability of the composition of the present invention at room temperature to heating below 80 °C and the adhesiveness to various substrates can be improved. Specifically, the (D) component is a catalyst for condensation reaction or its condensation reaction product selected from the group consisting of tetra-tert-butoxytitanium, bis(isopropoxy)bis(ethyl acetoacetate)titanium, and chelated aluminum complex, which promotes the condensation reaction of polyorganosiloxane to cure it. Examples of the chelated aluminum complex include: alkylaluminum diisopropyl acetoacetate, aluminum acetylacetonate, and mixtures thereof.

[0092] (D) The content of the component is a catalytic amount that varies depending on the type of catalyst and the type of composition. The amount is preferably 0.5% by mass or less, more preferably in the range of 0.001 to 0.500% by mass, relative to the total mass of the curable polyorganosiloxane composition.

[0093] (D) Bis(isopropoxy)bis(ethyl acetoacetate)titanium or its condensation reaction product in the component has the following advantages. Even when used in a small amount, sufficient improvement in adhesiveness during low-temperature curing can be expected. For example, even when it is 0.050% by mass or less, preferably in the range of 0.001 to 0.050% by mass, sufficient curability and adhesiveness can be achieved for metal substrates such as aluminum.

[0094] [(E) component]

[0095] The curable polyorganosiloxane composition of the present invention contains a curing inhibitor as a component for improving storage stability, operability, and shelf life. Examples of the (E) component include: acetylene compounds such as 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, 2-phenyl-3-butyn-2-ol, 1-ethynyl-1-cyclohexanol, and 1-ethynyl-2-cyclohexanol; enyne compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; triazoles such as 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, and benzotriazole; phosphines; thiols; and hydrazines.

[0096] The content of component (E) should be appropriately selected according to the curing conditions of the curable polyorganosiloxane composition of the present invention, and is preferably in an amount of 0.001 to 1.0% by mass, more preferably in an amount of 0.01% to 0.8% by mass, relative to the total mass of the curable polyorganosiloxane composition. In particular, relative to the total mass of the curable polyorganosiloxane composition, the content of the compound having a carbon-carbon triple bond in the molecule in component (E) is preferably in an amount of 0.001 to 0.5% by mass, more preferably in an amount of 0.01% to 0.3% by mass.

[0097] [Component (F)]

[0098] Component (F) is a trialkoxysilyl group-containing siloxane having one silicon atom-bonded hydrogen atom in one molecule and having at least one trialkoxysilyl group, and is an optional component that achieves firm and flexible adhesion to a substrate even in a small amount of adhesion mode other than low-temperature adhesiveness. Since component (F) has a trialkoxysilyl group, it has excellent reactivity and multiple condensation-reactive functional groups react simultaneously. Therefore, compared with an organohydrogenpolysiloxane having a hydroxyl group or an alkoxy group, it has the advantage of significantly improving adhesiveness even in a low-temperature and short-time curing reaction.

[0099] This trialkoxysilyl group-containing siloxane has a silicon atom-bonded hydrogen atom in the molecule, and thus reacts with component (A) together with other crosslinking agents (component (B)) during the curing reaction and is introduced into the cured product. Here, with respect to component (F), at least a part of it can be premixed with component (A) to cause an addition reaction in advance, or it can be added as a separate component. In addition, the trialkoxysilyl group is preferably a trimethoxysilyl group or a triethoxysilyl group, and the groups other than the silicon atom-bonded hydrogen atom and the alkoxysilyl group in component (F) are preferably non-reactive functional groups selected from alkyl groups and aryl groups.

[0100] Preferably, component (F) is an alkoxysilyl group-containing siloxane having a silicon atom-bonded hydrogen atom and an alkoxysilyl group at both ends of the polysiloxane represented by the following formula.

[0101] [Chemical formula 2]

[0102]

[0103] (In the formula, R 1 is the same or different and is a monovalent hydrocarbon group not having an aliphatic unsaturated bond, R 2 is an alkyl group, R 3 is an alkylene group, and p is an integer of 1 to 50).

[0104] In the above formula, R 1is the same as or different from a monovalent hydrocarbon group having no aliphatic unsaturated bond, examples of which include: alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, and octadecyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, phenethyl, and phenylpropyl; and halogenated alkyl groups such as 3-chloropropyl and 3,3,3-trifluoropropyl. Preferably, it is an alkyl group or an aryl group, and particularly preferably, it is a methyl group or a phenyl group. Further, in the above formula, R 2 is an alkyl group, examples of which include: methyl, ethyl, propyl, butyl, pentyl, and hexyl. Preferably, it is a methyl group or an ethyl group. R 3 is an alkylene group, preferably an alkylene group having 2 to 10 carbon atoms, and particularly preferably an ethylene group or a propylene group. Further, in the above formula, p is an integer of 1 to 50, preferably an integer of 1 to 10, and particularly preferably an integer of 1 to 5.

[0105] As such a component (F), examples include: a siloxane containing an alkoxysilyl group represented by the formula:

[0106] [Chemical formula 3]

[0107]

[0108] a siloxane containing an alkoxysilyl group represented by the formula:

[0109] [Chemical formula 4]

[0110]

[0111] a siloxane containing an alkoxysilyl group represented by the formula:

[0112] [Chemical formula 5]

[0113]

[0114] a siloxane containing an alkoxysilyl group represented by the formula:

[0115] [Chemical formula 6]

[0116]

[0117] a siloxane containing an alkoxysilyl group represented by the formula: For these siloxanes containing an alkoxysilyl group, one kind can be used, or two or more kinds can be used in combination. Also, a part or all of the methyl groups can be replaced with other alkyl groups, halogenated alkyl groups, aryl groups, or the like.

[0118] From the viewpoint of technical effects, the component (F) is preferably a compound represented by the formula:

[0119] [Chemical formula 7]

[0120]

[0121] Trimethoxysilyl group-containing disiloxane represented.

[0122] More specifically, relative to the entire curable polyorganosiloxane composition, a polyorganosiloxane having at least one silicon atom bonded in one molecule and represented by the general formula:

[0123] [Chemical formula 8]

[0124]

[0125] (In the formula, R 1 is the same or different and is a monovalent hydrocarbon group not having an aliphatic unsaturated bond, R 2 is an alkyl group, R 3 is the same or different and is an alkylene group, a is an integer of 0 to 2, and p is an integer of 1 to 50.)

[0126] The content of the polyorganosiloxane having an alkoxysilyl group represented is less than 5.0% by mass, preferably less than 3.0% by mass, and more preferably less than 1.0% by mass. Most preferably, the composition of the present invention does not contain the polyorganosiloxane having an alkoxysilyl group as described above. It should be noted that the functional groups exemplified as R 1 , R 2 and R 3 are the same as the respective functional groups in the (F) component.

[0127] Relative to the total mass of the curable polyorganosiloxane composition, the content of the (F) component is preferably in an amount of 0.05% by mass to 10% by mass, and more preferably in an amount of 0.1% by mass to 5.0% by mass.

[0128] [(G) component]

[0129] Component (G) is a component different from component (F) and is used to impart good adhesiveness to the crosslinked product of the above composition. It is at least one adhesion promoter, preferably at least one adhesion promoter selected from the group consisting of the following components: (i) a siloxane having at least one silicon atom-bonded alkenyl or silicon atom-bonded hydrogen atom and silicon atom-bonded alkoxy group in one molecule; (ii) an organosiloxane having at least one silicon atom-bonded alkenyl, silicon atom-bonded alkoxy group, and silicon atom-bonded monovalent organic group containing an epoxy group in one molecule; (iii) a mixture or reaction mixture of a silane or siloxane having at least one silicon atom-bonded alkoxy group in one molecule and an organosiloxane having at least one silicon atom-bonded hydroxyl group and silicon atom-bonded alkenyl group in one molecule; (iv) a mixture or reaction mixture of an organosilane or organosiloxane having at least one silicon atom-bonded alkoxy group and silicon atom-bonded monovalent organic group containing an epoxy group in one molecule and an organosiloxane having at least one silicon atom-bonded hydroxyl group and silicon atom-bonded alkenyl group in one molecule; (v) an alkylalkoxysilane; and (vi) a silane or alkane having at least one terminal trialkoxysilyl group that does not belong to the above component (F) or (v).

[0130] As the molecular structure of the siloxane having at least one silicon atom-bonded alkenyl or silicon atom-bonded hydrogen atom and silicon atom-bonded alkoxy group in one molecule in component (G), examples include linear, partially branched linear, branched, cyclic, and network structures, and linear, branched, or network structures are particularly preferred. As the silicon atom-bonded alkenyl group in the siloxane, examples include vinyl, allyl, butenyl, pentenyl, and hexenyl groups, and vinyl group is particularly preferred. In addition, as the silicon atom-bonded alkoxy group in the siloxane, examples include methoxy, ethoxy, propoxy, butoxy, and methoxyethoxy groups, and methoxy group is particularly preferred. In addition, as the group bonded to the silicon atom other than the alkenyl group, hydrogen atom, and alkoxy group in the siloxane, examples include substituted or unsubstituted monovalent hydrocarbon groups such as alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl groups; aryl groups such as phenyl, tolyl, xylyl, and naphthyl groups; aralkyl groups such as benzyl and phenethyl groups; halogenated alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl groups; epoxypropoxyalkyl groups such as 3-glycidoxypropyl and 4-glycidoxybutyl groups; (3,4-epoxycyclohexyl)alkyl groups such as 2-(3,4-epoxycyclohexyl)ethyl and 3-(3,4-epoxycyclohexyl)propyl groups; and epoxyethanealkyl groups containing an epoxy group such as 4-epoxyethanebutyl and 8-epoxyethaneoctyl groups. From the viewpoint of imparting good adhesiveness to various substrates, it is preferred to have at least one monovalent organic group containing an epoxy group in one molecule. The viscosity of such a siloxane is not limited, but it is preferably in the range of 1 to 500 mPa·s at 25°C.

[0131] In addition, in a mixture of a silane or siloxane having at least one alkoxysilyl bond in one molecule and an organosiloxane having at least one hydroxylsilyl bond and at least one vinylsilyl bond in one molecule in the component (G), examples of the alkoxysilyl bond in the former silane include methoxy, ethoxy, propoxy, butoxy, and methoxyethoxy, with methoxy being particularly preferred. In addition, in addition to the above alkoxysilyl bonds, the silicon atom of the silane may have at least one group selected from the group consisting of alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; alkenyl groups such as vinyl, allyl, butenyl, pentenyl, and hexenyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; substituted or unsubstituted monovalent hydrocarbon groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl; epoxypropylalkyl groups such as 3-glycidoxypropyl and 4-glycidoxybutyl; (3,4-epoxycyclohexyl)alkyl groups such as 2-(3,4-epoxycyclohexyl)ethyl and 3-(3,4-epoxycyclohexyl)propyl; and epoxyethanealkyl groups such as 4-epoxybutyl and 8-epoxyoctyl. From the viewpoint of imparting good adhesiveness to various substrates, a monovalent organic group containing at least one epoxy group in one molecule is preferred.

[0132] In addition, examples of the molecular structure of the former siloxane include linear, linear with some branched chains, branched, cyclic, and network structures, with linear, branched, or network structures being particularly preferred. Examples of the alkoxysilyl bond in the siloxane include methoxy, ethoxy, propoxy, butoxy, and methoxyethoxy, with methoxy being particularly preferred. In addition, in addition to the above alkoxysilyl bonds, the silicon atom of the siloxane may have at least one group selected from the group consisting of alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; alkenyl groups such as vinyl, allyl, butenyl, pentenyl, and hexenyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; substituted or unsubstituted monovalent hydrocarbon groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl; epoxypropylalkyl groups such as 3-glycidoxypropyl and 4-glycidoxybutyl; (3,4-epoxycyclohexyl)alkyl groups such as 2-(3,4-epoxycyclohexyl)ethyl and 3-(3,4-epoxycyclohexyl)propyl; and epoxyethanealkyl groups such as 4-epoxybutyl and 8-epoxyoctyl. From the viewpoint of imparting good adhesiveness to various substrates, a monovalent organic group containing at least one epoxy group in one molecule is preferred. The viscosity of such a siloxane is not limited, but it is preferably in the range of 1 to 500 mPa·s at 25°C.

[0133] In addition, as the molecular structure of the latter silicone oxide, examples include: linear, linear with some branched chains, branched, cyclic, and network structures, with linear, branched, or network structures being particularly preferred. As the alkenyl group bonded to the silicon atom in the silicone oxide, examples include: vinyl, allyl, butenyl, pentenyl, and hexenyl, with vinyl being particularly preferred. In addition, as the group bonded to the silicon atom in the silicone oxide other than the hydroxyl group and the alkenyl group, examples include: alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; and substituted or unsubstituted monovalent hydrocarbon groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl. The viscosity of such a silicone oxide is not limited, but it is preferably in the range of 1 to 500 mPa·s at 25°C.

[0134] The ratio of the silane or silicone oxide having at least one alkoxysilyl group bonded to a silicon atom in one molecule to the silicone oxide having at least one hydroxylsilyl group and at least one alkenylsilyl group bonded to a silicon atom in one molecule is not limited. From the viewpoint of imparting particularly good adhesiveness, the weight ratio of the former silane or silicone oxide to the latter silicone oxide is preferably in the range of 1 / 99 to 99 / 1.

[0135] As the tackifier of the present invention, a reaction mixture of an alkoxysilane having an amino-containing organic group and an alkoxysilane having an epoxy-containing organic group can be used. Preferably, the reaction ratio is in the range of (1:1.5) to (1:5) in terms of molar ratio, and particularly preferably in the range of (1:2) to (1:4). This component can be easily synthesized by mixing the alkoxysilane having an amino-containing organic group and the alkoxysilane having an epoxy-containing organic group as described above and reacting them at room temperature or by heating.

[0136] In particular, in the present invention, it is particularly preferred to contain a compound cyclized by transesterification, especially when reacting an alkoxysilane having an amino-containing organic group with an alkoxysilane having an epoxy-containing organic group by the method described in Japanese Patent Laid-Open No. 10-195085, and having the general formula:

[0137] [Chemical formula 9]

[0138]

[0139] {In the formula, R 1 is an alkyl group or an alkoxy group, and R 2 are the same or different and are selected from those represented by the general formula:

[0140] [Chemical formula 10]

[0141]

[0142] -R 7 -O-R 8

[0143] (wherein, R 4 is an alkylene or an alkyleneoxyalkylene, R 5 is a monovalent hydrocarbon group, R 6 is an alkyl group, R 7 is an alkylene group, R 8 is an alkyl group, an alkenyl group or an acyl group, and a is 0, 1 or 2.)

[0144] A group in the group consisting of the represented groups, R 3 is the same or different and is a hydrogen atom or an alkyl group.}

[0145] A carbocyclic silatrane derivative represented by. As such a carbocyclic silatrane derivative, for example, is shown: A silatrane derivative having an alkenyl group and a silicon atom-bonded alkoxy group in one molecule represented by the following structure.

[0146] [Chemical formula 11]

[0147]

[0148] This component is an organic compound having at least two alkoxysilyl groups in one molecule, and having a bond other than a silicon-oxygen bond between these silyl groups. In addition to improving the initial adhesiveness when used alone, particularly by using it in combination with other tackifiers, it plays a role in improving the adhesive durability of the cured product containing this adhesion promoter under severe conditions.

[0149] The alkylalkoxysilane as the component (G) is a component widely used as a silane coupling agent or a crosslinking agent in a condensation reaction, and is a component selected from alkyltrialkoxysilanes, dialkyldialkoxysilanes, and trialkylalkoxysilanes. Specifically, preferably exemplified are: methyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane or the like.

[0150] Silanes or alkanes that are not the above-mentioned (F) component and alkylalkoxysilanes and have at least one terminal trialkoxysilyl group include: 3-glycidoxyprolyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, bis(trimethoxysilyl)ethane, 1,2-bis(trimethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethane, 1,1-bis(trimethoxysilyl)ethane, 1,4-bis(trimethoxysilyl)butane, 1,4-bis(triethoxysilyl)butane, 1-methyldimethoxysilyl-4-trimethoxysilylbutane, 1-methyldiethoxysilyl-4-triethoxysilylbutane, 1,5-bis(trimethoxysilyl)pentane, 1,5-bis(triethoxysilyl)pentane, 1,4-bis(trimethoxysilyl)pentane, 1,4-bis(triethoxysilyl)pentane, 1-methyldimethoxysilyl-5-trimethoxysilylpentane, 1-methyldiethoxysilyl-5-triethoxysilylpentane, 1,6-bis(trimethoxysilyl)hexane, 1,6-bis(triethoxysilyl)hexane, 1,4-bis(trimethoxysilyl)hexane, 1,5-bis(trimethoxysilyl)hexane, 2,5-bis(trimethoxysilyl)hexane, 1-methyldimethoxysilyl-6-trimethoxysilylhexane, 1-phenyldiethoxysilyl-6-triethoxysilylhexane, 1,7-bis(trimethoxysilyl)heptane, 2,5-bis(trimethoxysilyl)heptane, 2,6-bis(trimethoxysilyl)heptane, 1,8-bis(trimethoxysilyl)octane, 2,5-bis(trimethoxysilyl)octane, 2,7-bis(trimethoxysilyl)octane, 1,9-bis(trimethoxysilyl)nonane, 2,7-bis(trimethoxysilyl)nonane, 1,10-bis(trimethoxysilyl)decane, 3,8-bis(trimethoxysilyl)decane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane.

[0151] The compounding amount of the (G) component is an amount sufficient to impart good adhesiveness to the crosslinked product of the above composition. For example, it is preferably an amount in the range of 0.01 to 20 parts by mass, particularly preferably in the range of 0.1 to 10 parts by mass, relative to 100 parts by mass of the (A) component. The reason is that when the compounding amount of the (G) component is less than the amount in this range, the adhesiveness of the cured product tends to decrease. On the other hand, even if it exceeds this range, it does not affect the adhesiveness, but rather the stability of the obtained silicone elastomer tends to decrease.

[0152] [Component (H)]

[0153] The curable polyorganosiloxane composition of the present invention may optionally further contain (H) inorganic filler. When the inorganic filler is included, it is preferably one or more selected from the following fillers: reinforcing filler, thermally conductive filler, and electrically conductive filler. In particular, the curable polyorganosiloxane composition of the present invention has the following advantages. Even when a large amount of inorganic filler, especially a thermally conductive filler or an electrically conductive filler such as silver powder and fine particles coated with silver, is incorporated, it has good adhesiveness to resin and metal substrates through a low-temperature and short-time curing reaction.

[0154] The reinforcing filler is a component for imparting mechanical strength to the silicone rubber cured product obtained by curing the curable polyorganosiloxane composition of the present invention and improving the performance as a protective agent or an adhesive. Examples of such reinforcing fillers include inorganic fillers such as fumed silica fine powder, precipitated silica fine powder, calcined silica fine powder, fumed titanium dioxide fine powder, quartz fine powder, calcium carbonate fine powder, diatomaceous earth fine powder, alumina fine powder, aluminum hydroxide fine powder, zinc oxide fine powder, and zinc carbonate fine powder. It may also contain inorganic fillers surface-treated with treatment agents such as organoalkoxysilanes such as methyltrimethoxysilane, organohalosilanes such as trimethylchlorosilane, organosilazanes such as hexamethyldisilazane, and siloxane oligomers such as α,ω-silanol group-terminated dimethylsiloxane oligomer, α,ω-silanol group-terminated methylphenylsiloxane oligomer, and α,ω-silanol group-terminated methylvinylsiloxane oligomer.

[0155] There is no particular limitation on the particle size of the fine powder of the reinforcing filler. For example, the median particle size measured by laser diffraction / scattering particle size distribution may be in the range of 0.01 μm to 1000 μm.

[0156] The content of the reinforcing filler is not limited, but relative to the total mass of the curable polyorganosiloxane composition excluding the (H) component, it is preferably in an amount of 0.1 to 200% by mass, more preferably in an amount of 1 to 100% by mass.

[0157] The thermally conductive filler or the electrically conductive filler is a component for imparting thermal conductivity or electrical conductivity to the silicone rubber cured product obtained by curing the curable polyorganosiloxane composition of the present invention as desired, and is preferably at least one or more powders and / or fibers selected from the group consisting of pure metal, alloy, metal oxide, metal hydroxide, metal nitride, metal carbide, metal silicide, carbon, soft magnetic alloy, and ferrite, preferably metal-based powder, metal oxide-based powder, metal nitride-based powder, or carbon powder.

[0158] As pure metals, bismuth, lead, tin, antimony, indium, cadmium, zinc, silver, copper, nickel, aluminum, iron, and metallic silicon can be cited. As alloys, alloys composed of two or more metals selected from the group consisting of bismuth, lead, tin, antimony, indium, cadmium, zinc, silver, aluminum, iron, and metallic silicon can be cited. As metal oxides, aluminum oxide, zinc oxide, silicon oxide, magnesium oxide, beryllium oxide, chromium oxide, and titanium oxide can be cited. As metal hydroxides, magnesium hydroxide, aluminum hydroxide, barium hydroxide, and calcium hydroxide can be cited. As metal nitrides, boron nitride, aluminum nitride, and silicon nitride can be cited. As metal carbides, silicon carbide, boron carbide, and titanium carbide can be cited. As metal silicides, magnesium silicide, titanium silicide, zirconium silicide, tantalum silicide, niobium silicide, chromium silicide, tungsten silicide, and molybdenum silicide can be cited. As carbon, diamond, graphite, fullerene, carbon nanotube, graphene, activated carbon, and amorphous carbon black can be cited. As soft magnetic alloys, Fe-Si alloys, Fe-Al alloys, Fe-Si-Al alloys, Fe-Si-Cr alloys, Fe-Ni alloys, Fe-Ni-Co alloys, Fe-Ni-Mo alloys, Fe-Co alloys, Fe-Si-Al-Cr alloys, Fe-Si-B alloys, and Fe-Si-Co-B alloys can be cited. As ferrites, Mn-Zn ferrites, Mn-Mg-Zn ferrites, Mg-Cu-Zn ferrites, Ni-Zn ferrites, Ni-Cu-Zn ferrites, and Cu-Zn ferrites can be cited. In addition, fine powders obtained by vapor deposition or plating of metals such as gold, silver, nickel, and copper on the surfaces of fine powders of ceramics, glass, quartz, and organic resins can be cited.

[0159] It should be noted that silver powder, glass coated with metals such as silver, fine powders such as aluminum oxide, aluminum powder, aluminum oxide powder, zinc oxide powder, aluminum nitride powder, or graphite are preferred. In addition, when electrical insulation is required for this composition, metal oxide-based powders or metal nitride-based powders are preferred, and aluminum oxide powder, zinc oxide powder, or aluminum nitride powder is particularly preferred.

[0160] The shape of the heat-conductive filler or conductive filler is not particularly limited, and examples thereof include spherical, needle-like, disc-like, rod-like, and amorphous shapes, with spherical or amorphous shapes being preferred. In addition, the average particle size of component (H) is not particularly limited, but it is preferably in the range of 0.01 to 500 μm, and more preferably in the range of 0.01 to 300 μm.

[0161] Preferably, these heat-conductive fillers or conductive fillers are heated and mixed with the component (F) and the like under reduced pressure at a temperature of 100 to 200 °C. In particular, when the component (F) is a siloxane having an alkoxysilyl group-containing group, a composition with low viscosity and excellent handling workability can sometimes be obtained even with high filling through surface treatment of the heat-conductive filler or conductive filler.

[0162] The compounding amount of such a heat conductive filler or an electrically conductive filler is not particularly limited, but is preferably in an amount of 0.1 to 3000% by mass, more preferably in an amount of 1 to 1500% by mass, relative to the total mass of the curable polyorganosiloxane composition excluding the component (H). This is because, due to the constitution of the curable polyorganosiloxane composition containing the components (A) to (E) of the present invention, particularly by using the component (C) and the component (D) in combination, even in the case of containing a large amount of a heat conductive filler or an electrically conductive filler, good adhesiveness to a substrate can be achieved by a curing reaction at a low temperature and for a short time.

[0163] In addition, within the scope not impairing the object of the present invention, the curable polyorganosiloxane composition of the present invention may optionally contain: organic solvents such as toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, hexane, and heptane; non-crosslinkable dimeric organosiloxanes such as α,ω-trimethylsiloxy-terminated dimethylpolysiloxane and α,ω-trimethylsiloxy-terminated methylphenylpolysiloxane; flame retardants such as carbon black; antioxidants such as hindered phenol antioxidants; heat resistant agents such as iron oxide; plasticizers such as dialkylsiloxane oligomers having hydroxyl dialkylsiloxy groups at both ends of the molecular chain; and other pigments, thixotropy imparting agents, and mildew proof agents.

[0164] The curable polyorganosiloxane composition of the present invention can be produced by uniformly mixing the above-mentioned polyorganosiloxanes, two different curing catalysts, an adhesion promoter, and other optional components. The mixing method of each component of the polyorganosiloxane composition may use a conventionally known method and is not particularly limited, but usually a uniform mixture is formed by simple stirring. In addition, in the case of containing solid components such as inorganic fillers as optional components, it is more preferable to use a mixing device for mixing. There is no particular limitation on such a mixing device, and examples thereof include: single-screw or twin-screw continuous mixers, two-roll mixers, Ross mixers, Hobart mixers, dental material mixers, planetary mixers, kneaders, Henschel mixers, and drum mixers.

[0165] The curable polyorganosiloxane composition of the present invention can be used as a one-component curable polyorganosiloxane composition, and is stable even when stored in a one-component state and has excellent durability.

[0166] Specifically, the curable polyorganosiloxane composition of the present invention can be produced by uniformly mixing the components (A) to (E) under moisture isolation, mixing the components (F) to (H) as needed, and further mixing other optional components. The produced curable polyorganosiloxane composition can be rapidly cured by heating from room temperature to 80°C to form a silicone rubber.

[0167] The curable polyorganosiloxane composition of the present invention adheres well to various adherends or substrates. Examples of the adherends or substrates include: adherends or substrates such as glass, ceramics, mortar, concrete, wood, aluminum, copper, brass, zinc, silver, stainless steel, iron, galvanized iron sheet, tin-plated iron sheet, nickel-plated surface, epoxy resin, and phenolic resin. In addition, examples include adherends or substrates of thermoplastic resins such as polycarbonate resin, polyester resin, ABS resin, nylon resin, polyvinyl chloride resin, polyphenylene sulfide resin, polyphenylene ether resin, and polybutylene terephthalate resin. In addition, in the case where stronger adhesiveness is required, the above-mentioned adhesion promoter can be blended. However, in addition to this, an appropriate primer can be coated on the surface of these adherends or substrates so that the curable polyorganosiloxane composition of the present invention adheres to the primer-coated surface.

[0168] The method of applying the curable polyorganosiloxane composition of the present invention to an adherend or substrate is not limited and can be carried out by coating or dispensing. For example, coating methods such as gravure coating, offset coating, offset gravure, roll coating, air knife coating, curtain coating, comma coating, and rod coating can be used, or a method of applying a small amount of the composition to a specific position by using a dispenser using a discharge method such as syringe type, volumetric metering type, non-contact type, tube type, or plunger type can be used.

[0169] The curable polyorganosiloxane composition of the present invention is preferably used as a caulking agent, potting material, sealing material, and adhesive for building components, electrical / electronic components, and vehicle components. Specifically, it can be suitably used as a caulking agent for bonding glass; a sealing material for a bathtub unit; an adhesive and a sealing material for lighting components of vehicles such as automobiles; a protective agent or an adhesive (sealing material, coating material, potting agent, adhesive) for electrical / electronic components, etc.

[0170] The curable polyorganosiloxane composition of the present invention has an excellent effect of improving the initial adhesiveness to various substrates contacted during the curing process, especially metal substrates such as unwashed aluminum die-castings; organic resins such as polybutylene terephthalate (PBT) resin, polyphenylene sulfide (PPS) resin, and polycarbonate (PC) resin. After curing, especially the adhesive durability is excellent, and high adhesive strength can be achieved. Therefore, it is particularly useful as a protective agent or an adhesive composition for electrical / electronic components. In addition, the curable polyorganosiloxane composition of the present invention can be cured at a lower temperature. Therefore, it can be particularly suitably used as a protective agent or an adhesive for plastic components that do not have heat resistance, an adhesive for optical components such as IR filters and camera lenses that are easily deteriorated due to deformation, and a protective agent or an adhesive for components such as motors and coils using magnets or microphones and speakers that are easily affected by magnetic force in electrical / electronic components.

[0171] Similarly, with respect to the curable polyorganosiloxane composition of the present invention, even when a large amount of inorganic fillers, particularly thermally conductive fillers or electrically conductive fillers such as silver powder or silver-coated fine particles, are incorporated, there is no problem of poor curing. The effect of improving the initial adhesiveness to various substrates in contact during the curing process is excellent, and the adhesiveness durability after curing is particularly excellent, enabling high adhesive strength. Therefore, it is useful as a thermally conductive or electrically conductive curable composition (for example, the same protective agent and adhesive as described above).

[0172] The curable polyorganosiloxane composition of the present invention can be cured at a lower temperature and can be cured at a temperature of 80°C or lower. The curable silicone composition of the present invention will cure even when heated at room temperature, but in order to cure it rapidly, it is preferably heated at a low temperature. The heating temperature is preferably from room temperature to 100°C, more preferably in the range of 40 - 80°C. It should be noted that the curable polyorganosiloxane composition of the present invention has the following advantages: it can undergo a good curing reaction even without being at a high temperature exceeding 120°C, and can achieve excellent initial adhesiveness and strong adhesive strength. Moreover, as described below, the curable polyorganosiloxane composition of the present invention can be stably stored as a one-component composition at a low temperature (particularly -20°C to 5°C).

[0173] [One-component composition]

[0174] The curable polyorganosiloxane composition of the present invention is a one-component composition in which all components are premixed. Even without using a multi-component dosage form in which a catalyst as a curing agent is separately separated, it can be stably stored and used as a one-component composition at a low temperature, and as described above, excellent adhesiveness to substrates can be achieved even when cured at around 80°C. Thus, it has the following advantages: it does not require processes such as prior mixing required for multi-component compositions, can be used simply, and does not cause problems such as material loss. Moreover, the curable polyorganosiloxane composition of the present invention can be stably stored even when a premixed package is formed on a small scale, and thus has the following advantages: it can provide stable and economical products in micro-amount coating that requires small-scale discharge and use.

[0175] [Cured product]

[0176] The present invention also relates to a cured product of the curable polyorganosiloxane composition of the present invention. The curable polyorganosiloxane of the present invention can provide a silicone rubber composition having a JIS A hardness of 5 or more, preferably 10 - 90, by curing. That is, the JIS A hardness of the cured product of the curable polyorganosiloxane composition of the present invention is 5 or more, preferably 10 - 90. Since the hardness of the cured product of the curable polyorganosiloxane composition is within the above range, a cured product having excellent adhesiveness can be obtained.

[0177] [Protective agent or adhesive and electronic device]

[0178] The curable polyorganosiloxane composition of the present invention can provide an electrical / electronic device having a cured product thereof. In particular, the composition has the following characteristics. With the above configuration, even in a small amount and in a thin layer form, it can be firmly and initially adhered to the adherend, and high adhesive strength can be achieved. In addition, it has the following characteristics. Whether it is a one-component type or not, it can be cured at low temperature to achieve firm adhesion. Therefore, the adhesive layer formed from the curable polyorganosiloxane composition of the present invention is firmly bonded to various adherends, forming an adhesive and sealing state that is not easily peeled off by interface peeling or the like (cohesive failure mode occurs during forced peeling). Specifically, the curable polyorganosiloxane composition of the present invention is preferably used for electrical / electronic devices having an adhesive layer or a protective layer. In addition, with respect to the curable polyorganosiloxane composition of the present invention, even for bonding methods other than thin film bonding, it exhibits high initial adhesiveness and adhesive force to the adherend. Therefore, it is also useful as a thick coating, potting agent, encapsulant or sealant used in the past, and can provide an electrical / electronic device having an adhesive layer or a protective layer.

[0179] Regarding the electrical / electronic components of the present invention, there is no particular limitation as long as they can be encapsulated or sealed with the above-described composition. For example, electronic devices such as circuits or electrodes formed with metal electrodes such as silver, copper, aluminum or gold, or metal oxide film electrodes such as ITO (Indium Tin Oxide) on substrates such as glass, epoxy resin, polyimide resin, phenolic resin or ceramic are exemplified. The protective agent or adhesive containing the curable polyorganosiloxane composition of the present invention is a one-component type and has low-temperature curability. Therefore, it has excellent operability. In addition, the effect of improving the initial adhesiveness is excellent, and the adhesive durability after curing is particularly excellent, and high adhesive strength can be achieved. Therefore, when used as an adhesive, potting material, coating material or sealing material for bonding, encapsulating or sealing electrical / electronic components, the reliability and durability of these electrical / electronic components can be improved. In particular, it can be suitably used as a protective agent or adhesive for plastic components, an adhesive for optical components, and a protective agent or adhesive for components such as motors, coils, microphones and speakers.

[0180] The protective agent or adhesive for electrical / electronic components of the present invention is also useful as a sealing material for structures composed of metal and / or resin, such as peripheral components of electrical / electronic devices, in-vehicle component boxes, terminal boxes, lighting components, and modules for solar cells, etc., which require durability, water resistance, etc. For example, when applied to circuit boards and their storage boxes for power semiconductor applications such as engine control, power transmission systems, and air-conditioning control in transport aircraft, the initial adhesiveness and adhesive durability are also excellent. Moreover, when assembled in in-vehicle electronic components such as electronic control units (ECUs) and used in harsh environments, it has the following advantages: achieving excellent adhesive durability and improving the reliability, durability, and water resistance to rain, etc. of these power semiconductors, in-vehicle components, etc. Its usage method is not particularly limited. For example, it can be used in the form of an elastic sealing material in the waterproof structure of an in-vehicle engine control circuit described in Japanese Patent Application Laid-Open No. 2007-235013. Similarly, it can also be used as a sealing material for waterproofing purposes in an automotive wire harness with terminals described in Japanese Patent Application Laid-Open No. 2009-135105, and can also be used as a water-stopping agent formed of silicone resin in the water-stopping method of wires and the water-stopping structure of wires described in Japanese Patent Application Laid-Open No. 2012-204016. Moreover, it can also be used as a sealing resin in solar cell modules, terminal boxes, and connection methods of solar cell modules as described in Japanese Patent Application Laid-Open No. 2002-170978, etc.

[0181] The protective agent or adhesive for electrical / electronic components of the present invention can be used as a thermally conductive or electrically conductive material. Specifically, in order to cool heat-generating components through heat conduction, it is useful as a heat transfer material (thermally conductive member) sandwiched between the thermal boundary surface of the heat-generating component and a heat dissipation member such as a radiator or a circuit board, and can form a heat dissipation structure having it. Here, the type, size, and detailed structure of the heat-generating component are not particularly limited. In addition, depending on the filling amount of the thermally conductive filler, it can have a thermal conductivity of 2.0 W / mK or more, preferably 3.5 W / mK or more, and more preferably 4.0 W / mK or more. The electrical / electronic device having such a thermally conductive member is not particularly limited. For example, it includes: secondary batteries such as battery-type lithium-ion electrode secondary batteries and battery stack-type fuel cells; electronic circuit boards such as printed circuit boards; IC chips encapsulating optical semiconductor elements such as diodes (LEDs), organic field elements (organic ELs), laser diodes, and LED arrays; CPUs used in electronic devices such as personal computers, digital video discs, mobile phones, and smart phones; and LSI chips such as driver ICs and memories. In addition, when used as an electrically conductive material, it can be used for grounding, eliminating electricity, and EMI shielding of electrical / electronic components.

[0182] Examples

[0183] Hereinafter, examples are given to illustrate the present invention, but the present invention is not limited thereto. In addition, the adhesiveness of the curable polyorganosiloxane composition was evaluated by the following method.

[0184] (Examples 1 to 4 and Comparative Examples 1 to 3)

[0185] ><Preparation Method of Curable Polyorganosiloxane Composition>

[0186] The curable polyorganosiloxane compositions shown in Table 1 below were prepared. Specifically, components (A-1), (A-2), (A-3), (B), (E-1), and (E-2) were premixed to form a mixed solution. Then, component (C) was added to the mixed solution, and after thorough stirring, a defoaming process was carried out. In addition, components (D-1), (D-2), (D-3), (D-4), (F-1), (G-1), (G-2), and (G-3) were mixed, and then added to the above mixed solution through a barrel mixer for mixing. The resulting liquid was filled into a plastic tube sealed with aluminum.

[0187] [Evaluation of Curing Behavior]

[0188] The prepared curable polyorganosiloxane composition was measured in a moving die rheometer (MDR, manufactured by ALPHA TECHNOLOGY) under the condition of heating at 130°C for 30 minutes, and the initial values of T10 and the final torque value were set. Then, after standing for 7 days under the conditions of temperature 25 ± 2°C and humidity 50 ± 5%, when T10 in the measurement of the uncured curable polyorganosiloxane composition by the same method was 150% or more relative to the initial value or the final torque value was less than 80% relative to the initial value, it was set as "NG", and otherwise it was set as "OK".

[0189] [Evaluation of Adhesiveness (Failure Mode) in Adhesion Test]

[0190] As adherends, one polycarbonate (PC) resin plate and one polyphenylene sulfide (PPS) resin plate were respectively prepared. The surfaces of the adherends were pre-cleaned with isopropyl alcohol. For the prepared curable polyorganosiloxane composition, using a spacer made of Teflon (registered trademark), a 10 × 10 × 1 mm aluminum mold was pressed to a thickness of 360 μm, cured by heating at 110°C for two hours, and then left to stand and cool under the conditions of temperature 25 ± 2°C and humidity 50 ± 5% in a mold shear testing machine for the measurement of the failure mode in the adhesion test.

[0191] The failure state of the adhesive after fracture of the obtained adhesion test specimen was confirmed. The failure state of the adhesive is divided into three types: cohesive failure, thin-layer cohesive failure, and interfacial peeling (failure modes of the adhesive layer). In the case of an ideal adhesion state, the failure mode is cohesive failure. Here, "CF", "tCF", and "AF" in Table 1 below respectively represent the failure modes of "cohesive failure", "thin-layer cohesive failure", and "interfacial peeling".

[0192] "PPS" in Table 1 below is the result of using a polyphenylene sulfide resin plate as the adherend, and "PC" is the result of using a polycarbonate resin plate as the adherend. Furthermore, Si-H / Si-Vi in the table represents the ratio of the number of moles of silicon atoms bonded to hydrogen atoms to the number of moles of vinyl groups in the composition.

[0193] In Table 1, the respective components used are as follows. Note that the viscosity is the value measured by a rotational viscometer at 25°C.

[0194] (A-1)

[0195] A mixture of 70% by mass of dimethylpolysiloxane with dimethylvinylsilanyloxy groups capped at both ends of the molecular chain (viscosity: 2000 mPa·s, Vi content: 0.23% by mass) and 30% by mass of a siloxane resin represented by the formula: (CH 2 =CH(CH 3 ) 2 SiO 0.5 ) 4 ((CH 3 ) 3 SiO 0.5 ) 40 (SiO 2.0 ) 56 (Vi content: 2.0% by mass, weight-average molecular weight: 20000)

[0196] (A-2)

[0197] Dimethylpolysiloxane with dimethylvinylsilanyloxy groups capped at both ends of the molecular chain (viscosity: 10000 mPa·s, Vi content: 0.13% by mass)

[0198] (A-3)

[0199] A mixture of 74% by mass of dimethylpolysiloxane with dimethylvinylsilanyloxy groups capped at both ends of the molecular chain (viscosity: 2000 mPa·s, Vi content: 0.23% by mass) and 26% by mass of fumed silica surface-treated with hexamethyldisilazane

[0200] (B)

[0201] Methylhydrogensiloxane capped at both ends of the molecular chain with trimethylsilyloxy groups (SiH content: 1.6% by mass)

[0202] (C)

[0203] Platinum complex with 1,3 - divinyl - 1,1,3,3 - tetramethyldisiloxane (mass unit of platinum metal: 1.6% by mass)

[0204] (D - 1)

[0205] Tetra - tert - butoxytitanium

[0206] (D - 2)

[0207] Aluminum acetylalkoxydipropanolate represented by the following formula ( = aluminum diisopropyl acetylacetate containing C18 alkyl group)

[0208] [Chemical formula 12]

[0209]

[0210] (D - 3)

[0211] Diisopropyl titanate bis(acetylacetonate)

[0212] (D - 4)

[0213] Zirconium tetrakis(acetylacetonate)

[0214] (E - 1)

[0215] 1 - Ethynyl - 2 - cyclohexanol

[0216] (E - 2)

[0217] Tetramethyltetravinylcyclotetrasiloxane

[0218] (F - 1)

[0219] Siloxane containing SiH and trialkoxysilyl group represented by the following formula (viscosity: 1.6 mPa / s, SiH content: 0.35% by mass)

[0220] [Chemical formula 13]

[0221]

[0222] (G - 1)

[0223] Condensate of 3 - glycidoxypropyltrimethoxysilane and hydroxysilyl - terminated dimethylmethylvinylsilane (ratio 1:1, viscosity: 30 mPa / s)

[0224] (G - 2)

[0225] Hexamethoxysilylhexane

[0226] (G-3)

[0227] 3-Glycidoxypropyltrimethoxysilane

[0228] [Table 1]

[0229] Composition, Curing Behavior, and Adhesion of Curable Polyorganosiloxane Compositions

[0230]

[0231]

[0232] In Comparative Example 1 and Comparative Example 2, diisopropyl bis(acetylacetonato)titanate or zirconium tetra(acetylacetonato) was used as a catalyst for the condensation reaction, respectively. Compared with the case where a catalyst for the condensation reaction selected from the group consisting of tetra-tert-butoxytitanium and chelated aluminum complexes of the present invention or a condensation reaction product thereof was used, the curing behavior was poor. In addition, in the composition of Comparative Example 3 that did not contain a catalyst for the condensation reaction, interfacial peeling occurred from the beginning in the case of evaluating the failure mode with respect to PES.

[0233] On the other hand, the failure mode of the curable polyorganosiloxane compositions of the present application invention shown in Examples 1 to 4 with respect to PC was cohesive failure, and also cohesive failure under the curing conditions of 25 °C, 50% RH (relative humidity), and after 7 days with respect to PPS. That is, a strong adhesive strength with the adherend was achieved, and the curing behavior was also excellent.

[0234] (Examples 5 to 7 and Comparative Examples 4 and 5)

[0235] ><Preparation Method of Curable Polyorganosiloxane Composition>

[0236] Curable polyorganosiloxane compositions shown in Table 2 below were prepared. Specifically, components (A-1), (A-2), and (G-1) were premixed to form a mixed solution, and then component (F-2) or (G-4) was added to the mixed solution and mixed. Next, component (H-2) was added and mixed, and then component (H-3) was added and mixed. After that, component (H-1) was added and mixed. Components (B-2) and (E-2) were added to the mixed solution and mixed, and finally components (C) and (D-1) or (D-5) were added and mixed. The obtained mixed solution was defoamed, and after mixing, it was filled into a Nordson EFD syringe and allowed to stand at room temperature for 30 minutes.

[0237] [Evaluation of Adhesion (Failure Mode) in Adhesion Test]

[0238] Two aluminum-clad plates were used as substrates. The surfaces of the first substrate and the second substrate were pre-cleaned with isopropyl alcohol, and the prepared curable polyorganosiloxane composition was coated on the surface of the first substrate. The second substrate was pressed thereon, heated and cured at 80 °C for 1 hour, allowed to stand at room temperature for 1 day or 7 hours and then cooled, and used for the determination of the failure mode in the adhesion test.

[0239] The failure state of the adhesive after fracture of the obtained adhesion test specimen was confirmed. Herein, "CF" and "AF" in Table 2 below respectively indicate that the failure mode is "cohesive failure" and "interface peeling".

[0240] [Measurement of Tensile Strength]

[0241] The tensile strength of the adhesion test specimen obtained in the evaluation of adhesiveness (failure mode) was measured using a tensile testing machine (manufactured by Instron) under the conditions of a load of 1 kN, a pressing pressure of 60 psi, and a speed of 2 mm / min.

[0242] [Evaluation of Volume Resistivity]

[0243] The prepared curable polyorganosiloxane composition was molded on a 10×10×0.178 cm flat plate and cured at 80 °C under a pressure of 7 tons for 1 hour. The volume resistivity of the obtained test specimen was measured using Signatone Pro4-8000 and KeithlyMeter2400.

[0244] [Evaluation of Stability]

[0245] The prepared curable polyorganosiloxane composition was allowed to stand at -18 °C for 6 weeks, and then allowed to stand under the conditions of a temperature of 25±2 °C and a humidity of 50±5%, and it was investigated whether it was cured within 56 hours. The case where it was cured within 56 hours was set as "cured", and the case where it was not cured was set as "not cured".

[0246] In Table 2, the respective components used are as follows.

[0247] (A-1)

[0248] 70% by mass of dimethylpolysiloxane capped at both ends of the molecular chain with dimethylvinylsilanyloxy (viscosity: 2000 mPa / s, Vi content: 0.23% by mass) and 30% by mass of the compound represented by the formula: (CH 2 =CH(CH 3 ) 2 SiO 0.5 ) 4 ((CH 3 ) 3 SiO 0.5 ) 40(SiO 2.0 ) 56 A mixture of siloxane resins (Vi content: 2.0% by mass, weight average molecular weight: 20,000)

[0249] (A-2)

[0250] Dimethylpolysiloxane capped at both ends of the molecular chain with dimethylvinylsilanyloxy groups (viscosity: 10,000 mPa / s, Vi content: 0.13% by mass)

[0251] (B-2)

[0252] In the structural formula:

[0253] H(CH 3 ) 2 SiO((CH 3 ) 2 SiO) 3.34 ((CH 3 )HSiO) 5.32 Si(CH 3 ) 2 H

[0254] A dimethylsiloxane-methylhydrosiloxane copolymer capped at both ends of the molecular chain with dimethylhydrogensilanyloxy groups, represented by

[0255] (C)

[0256] Platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex

[0257] (D-1)

[0258] Tetra-tert-butoxytitanium

[0259] (D-5)

[0260] Di(isopropoxy)bis(ethyl acetoacetate)titanium

[0261] (E-2)

[0262] Tetramethyltetravinylcyclotetrasiloxane

[0263] (G-1)

[0264] The condensation reaction product of 3-glycidoxyprolyltrimethoxysilane and hydroxy-silyl-terminated dimethylmethylvinylsiloxane (ratio 1:1, viscosity: 30 mPa / s)

[0265] (F-2)

[0266] Hexamethoxysilylhexane

[0267] (G-4)

[0268] Tetraethyl orthosilicate

[0269] (H-1)

[0270] Silver sheet, manufactured by Metalor, Silver RA-0127

[0271] (H-2)

[0272] Silver-coated aluminum, manufactured by Potters Industries, Silver coated Aluminum

[0273] (H-3)

[0274] Silver-coated glass, manufactured by Potters Industries, Silver coated Glass

[0275] [Table 2]

[0276] Composition, curing behavior, tensile strength, volume shrinkage and stability of the curable polyorganosiloxane composition

[0277]

[0278]

[0279] The curable polyorganosiloxane compositions of the present invention shown in Examples 5 to 7 contain a large amount of various heat-conductive fillers, but the failure mode after heat curing at 80 °C (1 hour) for 7 days is cohesive failure, and the adhesive strength (=tensile strength) increases with time, showing good adhesiveness to the aluminum-clad plates used in this evaluation. In contrast, the adhesive strengths of the curable polyorganosiloxane compositions of Comparative Example 4 and Comparative Example 5, which do not contain tetra-tert-butoxytitanium and bis(isopropoxy)bis(ethyl acetoacetate)titanium, do not increase with time, and interfacial peeling occurs after 7 days, without sufficient improvement in adhesiveness being found. It should be noted that when tetra-tert-butoxytitanium and bis(isopropoxy)bis(ethyl acetoacetate)titanium are used within the range of the amounts used in the examples of the present application, the composition maintains good curability even when prepared as a single component and left standing at -18 °C for 6 weeks, and the single-component storage stability is also good.

[0280] Industrial applicability

[0281] The curable polyorganosiloxane composition of the present invention can be stored in a single-liquid form, so it has excellent workability. In addition, it can be cured even at a relatively low temperature and can exhibit excellent adhesiveness, so it can also exhibit good adhesive strength for substrates that are difficult to bond, such as resins. In addition, even in the case of low-temperature curing, it exhibits excellent adhesiveness, so it is useful as a protective agent or adhesive for plastic parts, an adhesive for optical parts, a protective agent or adhesive for parts such as motors, coils, microphones, and speakers. In addition, the curable polyorganosiloxane composition of the present invention can be cured even at a relatively low temperature even when a large amount of inorganic filler is incorporated, and exhibits excellent adhesiveness, so it is useful as a functional filler having thermal conductivity and conductivity.

Claims

1. A one - component curable polyorganosiloxane composition, which is composed of the following components (A) - (H): (A) A polyorganosiloxane having at least two alkenyl groups in one molecule; (B) A polyorganosiloxane having at least two silicon - bonded hydrogen atoms in one molecule; (C) A catalyst for hydrosilylation reaction; (D) Titanium bis(isopropoxide) bis(ethyl acetoacetate) or its condensation reaction product; (E) A curing inhibitor; (F) A trialkoxysilyl - containing siloxane represented by the following formula, [Chemical formula 1] In the formula, R 1 is the same or different and is a monovalent hydrocarbon group without aliphatic unsaturated bonds, R 2 is an alkyl group, R 3 is an alkylene group, and p is an integer from 1 to 50; (G) An adhesion promoter; and (H) A silver - containing inorganic conductive or heat - conductive filler, wherein, the content of component (H) is in an amount of 0.1 - 3000% by mass relative to the total mass of the curable polyorganosiloxane composition excluding component (H), wherein component (B) is included in an amount such that the molar ratio of silicon - bonded hydrogen atoms to alkenyl groups in all components of the curable polyorganosiloxane composition is in the range of 0.3 - 10, wherein, relative to the total mass of the curable polyorganosiloxane composition, the content of component (D) is 0.5% by mass or less, the content of the compound having a carbon - carbon triple bond in component (E) is in an amount of 0.001 - 0.5% by mass, and the content of component (F) is in an amount of 0.05 - 10% by mass, and the curable polyorganosiloxane composition provides a silicone rubber composition having a JIS A hardness of 5 or more upon curing.

2. The curable polyorganosiloxane composition according to claim 1, which can be cured at a temperature of 80°C or lower.

3. A protective agent or adhesive for electrical / electronic components, which comprises the curable polyorganosiloxane composition according to claim 1 or 2.

4. A conductive or heat - conductive curable composition, which comprises the curable polyorganosiloxane composition according to claim 1 or 2.

5. A cured product, which is a cured product of the curable polyorganosiloxane composition according to claim 1 or 2.

6. An electrical / electronic device, which comprises the cured product according to claim 5.

7. An electrical / electronic device, wherein, the electrical / electronic components are bonded, encapsulated, sealed or filled with the curable polyorganosiloxane composition according to claim 1 or 2.

8. A method for protecting electrical / electronic components, wherein, the curable polyorganosiloxane composition according to claim 1 or 2 is used.

9. A method for bonding electrical / electronic components, wherein, the curable polyorganosiloxane composition according to claim 1 or 2 is used.

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