Curable silicone composition containing diyne-containing amino-modified organopolysiloxane compound

Abstract

The present invention provides a curable silicone composition which is characterized by containing 100 parts by mass of (A) an organopolysiloxane compound that has a substituent represented by general formula (1) in each molecule and an effective amount of (B) a metal compound that is capable of catalyzing a [2+2+2] cycloaddition reaction. (In the formula, R1 independently represents a substituted or unsubstituted monovalent hydrocarbon group or a hydrogen atom, R2 independently represents a substituted or unsubstituted divalent hydrocarbon group, and R3 represents a divalent linking group.) As a result, the present invention provides: a curable silicone composition which is capable of having a [2+2+2] cycloaddition reaction progress under mild conditions; and a silicone cured product of the curable silicone composition.

Description

Curable silicone composition containing diyne-containing amino-modified organopolysiloxane compound

[0001] The present invention relates to a curable silicone composition containing an amino-modified organopolysiloxane compound that has a diyne in the molecule and is curable, a cured product thereof, and a method for producing said composition.

[0002] Silicone elastomers are elastic materials based on silicone resin, and because silicone itself has excellent heat and chemical resistance, they are widely used as coating agents, sealants, and encapsulants for semiconductor elements.

[0003] Curable silicone compositions are liquid silicone compositions during use, and can cure to form silicone elastomers when triggered by heat, light, or moisture in the air. Specific curing modes include radical addition reactions, hydrosilylation addition reactions, and condensation reactions. Radical addition reactions generally use peroxides, often requiring high temperatures to generate initiating species, and can suffer from poor surface curing due to oxygen inhibition. Hydrosilylation addition reactions can be cured at room temperature or by heating, depending on the catalyst and reaction inhibitor used. However, the presence or contact of curing inhibitors such as sulfur, phosphorus, nitrogen compounds, water, and organometallic salts can result in poor curing. Condensation reactions can cure at room temperature using moisture in the air, but they generate gas during curing, resulting in volumetric shrinkage and poor deep curing.

[0004] Many curable silicone compositions are used as materials in the periphery of electrical and electronic components and semiconductor elements. However, an increasing number of electrical and electronic components are heat-sensitive and cannot be exposed to high temperatures during mounting. This has created a demand for curable silicone compositions that can be cured under mild conditions of 100°C or less.

[0005] One reaction that can be used as a curing system is the [2+2+2] cycloaddition reaction of alkynes, which uses a transition metal as a catalyst to form carbon-carbon bonds between multiple bonds. The [2+2+2] cycloaddition reaction forms an aromatic ring from three triple bonds. It is a very useful reaction, producing no by-product gases during the reaction. However, there have been few reported examples of its application to organopolysiloxane compounds or their cured products. Furthermore, this reaction has a high activation barrier, and when using a catalyst stable at room temperature, high temperatures of 100°C or higher are required to drive the reaction. On the other hand, to drive the reaction under mild conditions below 100°C, a highly active catalyst is required. However, such catalysts require prior preparation and are deactivated under normal humidity conditions, making their use as compositions and long-term storage at room temperature or humidity difficult (Non-Patent Documents 1-3).

[0006] Reppe, W. et al. Justus Liebigs Ann. , 1948, 560, 104 Vollhardt, K. P. C. Angew. Chem. Int. Ed. Engl. 1984, 23, 539 Saito, S. ; Yamamoto, Y. Chem. Rev. 2000, 100, 2901

[0007] In view of the above circumstances, an object of the present invention is to provide a curable silicone composition that is capable of undergoing a [2+2+2] cycloaddition reaction under particularly mild conditions, and a cured silicone product thereof.

[0008] In order to solve the above problems, the present invention provides a curable silicone composition comprising: (A) 100 parts by mass of an organopolysiloxane compound having a substituent group represented by the following general formula (1) in the molecule; (In the formula, R １ are independently a substituted or unsubstituted monovalent hydrocarbon group or a hydrogen atom, R ２ are independently substituted or unsubstituted divalent hydrocarbon groups, R ３ is a divalent linking group; and (B) an effective amount of a metal compound capable of catalyzing a [2+2+2] cycloaddition reaction.

[0009] With such a curable silicone composition of the present invention, it is possible to proceed with a [2+2+2] cycloaddition reaction under mild conditions, and the composition can be cured to give a cured silicone product.

[0010] In the curable silicone composition of the present invention, R ２ is preferably a methylene group, and R １ It is also preferred that is a hydrogen atom.

[0011] Such organopolysiloxane compounds as component (A) are easy to synthesize.

[0012] In the composition of the present invention, the component (A) is preferably an organopolysiloxane compound having, on average, two or more substituents represented by the general formula (1) per molecule.

[0013] Such component (A) has, on average, four or more ethynylene groups per molecule that contribute to the [2+2+2] cycloaddition and are linked to each other via nitrogen atoms, allowing the [2+2+2] cycloaddition reaction to proceed more smoothly.

[0014] In the present invention, it is preferred to further contain (C) at least one inorganic or organic filler in an amount of 0.1 to 5,000 parts by mass per 100 parts by mass of component (A).

[0015] Component (C) of this kind is capable of imparting various properties to the curable silicone composition of the present invention, such as thermal conductivity, heat resistance, reinforcing properties, electrical conductivity, and design properties, and is also capable of providing a homogeneous composition that is not too viscous and therefore easy to handle.

[0016] In this case, the component (C) is preferably a filler made of one or more materials selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, carbon allotropes, resins, dyes, and pigments.

[0017] With such a component (C), it is possible to obtain a composition having the desired properties depending on the material.

[0018] The present invention also provides a cured silicone product obtained by curing the above-described curable silicone composition.

[0019] The silicone cured product of the present invention is an elastic material, and since the silicone itself has excellent heat resistance and chemical resistance, it is useful as a silicone elastomer used as a coating agent, sealing agent, or encapsulant for semiconductor elements.

[0020] The present invention also provides a method for producing a curable silicone composition, comprising the steps of: (A) 100 parts by mass of an organopolysiloxane compound having a substituent group represented by the following general formula (1) in the molecule; (In the formula, R １ are independently a substituted or unsubstituted monovalent hydrocarbon group or a hydrogen atom, R ２ are independently substituted or unsubstituted divalent hydrocarbon groups, R ３ is a divalent linking group; and (B) an effective amount of a metal compound capable of catalyzing a [2+2+2] cycloaddition reaction.

[0021] The method for producing a curable silicone composition of the present invention allows the silicone composition to be produced easily and efficiently.

[0022] According to the present invention, by introducing a specific structure into an organopolysiloxane compound, it is possible to provide organopolysiloxane compounds and silane compounds useful for [2+2+2] cycloaddition reactions. In particular, it is possible to provide a silicone composition that can be cured under mild conditions of 100°C or less. Because of this curing performance, it can be cured even when using heat-sensitive components that cannot be exposed to high temperatures during assembly, making it highly useful as a material used in the periphery of electrical and electronic components and semiconductor devices. Furthermore, the silicone cured product obtained by curing the composition is an elastic material, and since the silicone itself has excellent heat resistance and chemical resistance, it is useful as a silicone elastomer used as a coating agent, a sealant, an encapsulant for semiconductor devices, and the like. Furthermore, the method for producing a curable silicone composition of the present invention allows the above composition to be produced easily and efficiently.

[0023] As described above, there has been a need for the development of a curable silicone composition that can be cured under mild conditions of 100°C or below without the use of a highly active catalyst, that does not become deactivated under normal humidity conditions, and that can be easily used as a composition or stored at normal temperature or humidity for long periods of time.

[0024] As a result of intensive research aimed at solving the above problems, the present inventors discovered that by introducing a substituent having a specific structure into an organopolysiloxane compound, a [2+2+2] cycloaddition reaction can proceed under mild conditions, leading to the present invention.

[0025] That is, the present invention provides a curable silicone composition comprising: (A) 100 parts by mass of an organopolysiloxane compound having a substituent group represented by the following general formula (1) in the molecule; (In the formula, R １ are independently a substituted or unsubstituted monovalent hydrocarbon group or a hydrogen atom, R ２ are independently substituted or unsubstituted divalent hydrocarbon groups, R ３ is a divalent linking group; and (B) an effective amount of a metal compound capable of catalyzing a [2+2+2] cycloaddition reaction.

[0026] The present invention will be described in detail below, but the present invention is not limited thereto.

[0027] The present invention relates to a curable silicone composition and cured silicone product that contain an amino-modified organopolysiloxane compound that has a diyne in its molecule and is curable under mild conditions, for example, at 100°C or below, via a [2+2+2] cycloaddition reaction, and a metal catalyst that can catalyze the [2+2+2] cycloaddition reaction, as well as a method for producing such a composition.

[0028] [Component (A)] The organopolysiloxane compound that is component (A) of the present invention is an organopolysiloxane compound having a substituent group represented by the following general formula (1) in the molecule: Component (A) is a compound that contains a diyne having two carbon-carbon triple bonds, and this diyne contributes to [2+2+2] cycloaddition. (In the formula, R １are independently a substituted or unsubstituted monovalent hydrocarbon group or a hydrogen atom, R ２ are independently substituted or unsubstituted divalent hydrocarbon groups, R ３ is a divalent linking group.

[0029] In the above formula (1), R １ are independently a substituted or unsubstituted monovalent hydrocarbon group or a hydrogen atom. Specific examples of the monovalent hydrocarbon group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, cyclohexyl, octyl, and dodecyl; aryl groups such as phenyl, 1-naphthyl, 2-naphthyl, and tolyl; aralkyl groups such as benzyl and 2-phenylethyl; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, chlorine, and bromine, such as a chloromethyl group or a 3,3,3-trifluoropropyl group. From the viewpoint of ease of synthesis, etc., a methyl group, an ethyl group, a phenyl group, and a hydrogen atom are preferred, with a hydrogen atom being particularly preferred.

[0030] In the above formula (1), R ２ are independently substituted or unsubstituted divalent hydrocarbon groups. ２ may itself be the substituent represented by general formula (1) (in this case, a dendritic structure is formed via a tertiary nitrogen atom). Specific examples of the divalent hydrocarbon group include alkylene groups such as methylene, ethylene, ethylidene, propylene, trimethylene, propylidene, and isopropylidene. From the viewpoint of ease of synthesis, the methylene and ethylene groups are preferred, with the methylene group being particularly preferred.

[0031] In the above formula (1), R ３is a divalent linking group. The divalent linking group is not particularly limited, but examples include linear, branched, or ring-containing aliphatic hydrocarbon groups or aromatic hydrocarbon groups. The number of carbon atoms in the aliphatic / aromatic hydrocarbon group can be, for example, 1 to 20. The aliphatic hydrocarbon group or aromatic hydrocarbon group may have a substituent, and examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and a carbonyl group. Furthermore, a portion of the carbon atoms or hydrogen atoms constituting the hydrocarbon group may be substituted with a bond such as an ether bond, an ester bond, a carbonyl bond, a carbonate bond, a carbamate bond, an amino bond, a urethane bond, or a urea bond. As the divalent linking group, a linear aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a hydrocarbon group having an amino bond is preferred, with a linear aliphatic hydrocarbon group being particularly preferred. The linear aliphatic hydrocarbon group preferably has 1 to 20 carbon atoms, more preferably 1 to 10, and particularly preferably 1 to 3.

[0032] Specific examples of the substituent include: In the structural formulas described above, Me represents a methyl group, Et represents an ethyl group, and Ph represents a phenyl group.

[0033] Among the above substituents, the following structures are particularly preferred from the viewpoints of ease of synthesis and reactivity in the [2+2+2] cycloaddition reaction.

[0034] The component (A) preferably contains one or more, and particularly preferably two or more, of the substituents shown in formula (1) above per molecule. Such component (A) has at least two, and more preferably four or more, ethynylene groups that contribute to the [2+2+2] cycloaddition, and these ethynylene groups are linked to each other via nitrogen atoms, making it easy to synthesize and allowing the [2+2+2] cycloaddition reaction to proceed smoothly.

[0035] In the present invention, the component (A) is preferably an organopolysiloxane compound having, on average, two or more substituents per molecule represented by the general formula (1). Here, "having, on average, two or more per molecule" means that if the compound of component (A) is one type, it has two or more of the above substituents per molecule, and if it is two or more types, the sum of the number of the above substituents per molecule and the molar fraction of each molecule is two or more.

[0036] The molecular structure of component (A) is not particularly limited as long as it is a compound containing the substituent represented by formula (1), and examples thereof include a linear structure, a branched structure, a partially branched structure, and a linear structure having a cyclic structure. In particular, it is preferable for the main chain to have a linear structure in which the diorganosiloxane unit is repeated and both molecular chain terminals are blocked with triorganosiloxy groups. The organopolysiloxane having such a linear structure may also have a partially branched or cyclic structure. The substituent represented by formula (1) may be borne by the triorganosiloxy group at the molecular chain terminal, or by the partially branched or cyclic structure.

[0037] The component (A) preferably has an average molecular weight of 150 to 500,000 g / mol, particularly preferably 250 to 150,000 g / mol. The average molecular weight here means the sum of the products of the molecular weights and molar fractions of each compound, i.e., the number average molecular weight. The average molecular weight can be measured by GPC (gel permeation chromatography) using tetrahydrofuran as an eluent and polystyrene as a standard.

[0038] The kinematic viscosity of the component (A) at 25°C is preferably 1 to 500,000 mm ２ / s, more preferably in the range of 5 to 300,000 mm ２ / s. This kinematic viscosity is 10 to 100,000 mm ２ When the kinematic viscosity is 1 / s, the cured product obtained from the composition has excellent strength, fluidity, and workability. The kinematic viscosity is a value measured with an Ostwald viscometer at 25°C.

[0039] The component (A) preferably has an amine value of 0.1 to 2000 mg KOH / g, where the amine value is the number of mg of potassium hydroxide (KOH: 56.11) equivalent to the acid required to neutralize 1 g of sample.

[0040] The organopolysiloxane compound of the present invention that satisfies the above requirements is, for example, an organopolysiloxane compound represented by the following general formula (2): (In the formula, R ４ are each independently an unsubstituted or substituted monovalent hydrocarbon group, provided that R ４ at least one of the groups is a substituent represented by the above formula (1), and a+b+c+d is a number of 0 or more. However, in the case of a linear organopolysiloxane compound, a=2, b is preferably 2 or more and 800 or less, and c=d=0. In the case of a branched-chain organopolysiloxane compound, a or b is a number of 0 or more, b is preferably 2 or more and 800 or less, and c or d is 1 or more. In the case of a cyclic organopolysiloxane compound, a=0, b is preferably in the range of 3 to 10, more preferably in the range of 3 to 6, and c or d is a number of 0 or more.) Examples of the organopolysiloxane compound include organopolysiloxane compounds represented by the following formula: ４ ３ SiO １／２ ) or D unit (R ４ ２ SiO ２／２ At least one R in ４ is preferably a substituent represented by the above formula (1).

[0041] Specific examples of the organopolysiloxane compound and silane compound include those represented by the following structural formulas.

[0042] (In the formula, e, f, or g is a number of 0 or more, and e or f is more preferably a number of 2 or more and 800 or less. g is more preferably a number of 0 or more and 800 or less. h or i is preferably 0 or more, and h+i is preferably 20 or more and 800 or less.) In the structural formula described above, Me represents a methyl group, and Ph represents a phenyl group.

[0043] The metal-catalyzed [2+2+2] cycloaddition reaction is a direct and atom-efficient method for synthesizing fused polycyclic aromatic compounds. Component (A) of the present invention is a metal compound capable of catalyzing the [2+2+2] cycloaddition reaction, and has the advantage that the reaction proceeds under relatively mild conditions, particularly at temperatures below 100°C.

[0044] The component (A) may be used alone or in combination of two or more.

[0045] [Component (B)] Component (B) is a metal compound capable of catalyzing a [2+2+2] cycloaddition reaction, and is blended as a catalyst for curing the curable silicone composition of the present invention. Here, "capable of catalyzing a [2+2+2] cycloaddition reaction" means having catalytic activity for a [2+2+2] cycloaddition reaction. Hereinafter, this metal compound will also be referred to simply as a "catalyst," "metal catalyst," etc.

[0046] The metal compound of component (B) can be composed of a central metal atom, a ligand, and a counter ion. Examples of central metal atoms include those from Groups 4 to 12. Specific examples include those from Group 4 (titanium (Ti), zirconium (Zr), and hafnium (Hf)), Group 5 (vanadium (V), niobium (Nb), and tantalum (Ta)), Group 6 (chromium (Cr), molybdenum (Mo), and tungsten (W)), Group 7 (manganese (Mn), rhenium (Re)), Group 8 (iron (Fe), ruthenium (Ru), and osmium (Os)), Group 9 (cobalt (Co), rhodium (Rh), and iridium (Ir)), Group 10 (nickel (Ni), palladium (Pd), and platinum (Pt)), and Group 12 (zinc (Zn)). Among these, Ti, Nb, Ta, Co, Rh, Fe, Ru, Ir, or Pd is preferred, and Co, Rh, or Pd is more preferred. The central metal atom may be one type or two or more types, and when two or more types are used, they may all be the same metal or a combination of different metals.

[0047] The ligand is not particularly limited, and may be carbonyl (CO), ammonia, water, F － , Cl － ,Br－ , I － Halide ions such as cyanide ions (CN － ), P.F. ６ － , B.F. ４ － , NO ３ － , B.P.h. ４ － , ClO ４ － anions such as ammonium, sulfonium, and phosphonium; onium cations such as ammonium, sulfonium, and phosphonium; organic phosphorus compounds such as triphenylphosphine and 1,2-bis(diphenylphosphino)ethane; cyclopentadienyl (Cp) groups; pentamethylcyclopentadienyl (Cp) groups; ＊ ) group, cyclooctadiene (COD) group, cyclooctatriene (COT) group, norbornene group, norbornadiene group, and other olefins; dibenzylidene acetone, and other α,β-unsaturated ketones; acetyl group, benzoyl group, and other acyl groups; acetylacetone (acac), and other β-diketones; acetoethyl acetate, and other β-ketoesters; alkylamines; alkylenediamines; aniline; pyridine, and other amines; and alkoxy groups. Among these, carbonyl (CO), halide ions, cyclopentadienyl (Cp) group, triphenylphosphine, and dibenzylidene acetone are preferred. The ligand may be a monodentate ligand or a multidentate ligand (bidentate or higher).

[0048] The counter ion is not particularly limited, and may be a halide ion, a cyanide ion, a carbonate ion, or PF , which can also serve as a ligand. ６ － , B.F. ４ － , NO ３ － , B.P.h. ４ － , ClO ４ － and onium cations such as ammonium, sulfonium, and phosphonium. － is more preferred.

[0049] Particularly preferred metal compounds capable of catalyzing the [2+2+2] cycloaddition reaction are cyclopentadienylcobalt(I) dicarbonyl, tetrakis(triphenylphosphine)palladium(0), tris(dibenzylideneacetone)dipalladium(0), and tris(triphenylphosphine)rhodium(I) chloride.

[0050] The metal compound may be used after dilution, such as dissolving or dispersing, in a solvent as needed. As such a solvent, known solvents may be used, for example, alcohols such as methanol, ketones such as acetone, hydrocarbon solvents such as hexane, toluene, and xylene, halogenated hydrocarbon solvents such as methylene chloride, chloroform, and 1,2-dichloroethane, esters such as ethyl acetate, and solvents having a kinematic viscosity of 50,000 mm at 25°C, both ends of which are blocked with trimethylsilyl groups. ２ Examples of suitable polysiloxanes include dimethylpolysiloxane of formula (I) / s.

[0051] The concentration of the metal compound in the solvent (catalyst concentration) may be set as needed, for example, to 0.01 to 10% by mass, preferably 0.1 to 5% by mass, calculated as the mass of the central metal. A desired composition can be prepared by adding the diluted solution in an amount sufficient to contain a metal compound capable of catalyzing the [2+2+2] cycloaddition reaction described below.

[0052] The amount of the metal compound capable of catalyzing the [2+2+2] cycloaddition reaction should be an effective amount as a catalyst, i.e., an effective amount necessary to promote the curing reaction and cure the curable silicone composition of the present invention. Preferably, the amount is 0.1 to 10,000 ppm, more preferably 1 to 5,000 ppm, and even more preferably 10 to 3,000 ppm by mass, calculated as the central metal atom, relative to the total composition. If the amount of catalyst is equal to or greater than the lower limit, the catalytic effect can be obtained, and if it is equal to or less than the upper limit, the catalytic effect is sufficient and economical.

[0053] [Component (C)] The curable silicone composition of the present invention can optionally contain an inorganic or organic filler as component (C). Component (C) can impart various properties to the curable silicone composition of the present invention, such as thermal conductivity, heat resistance, reinforcing properties, electrical conductivity, and design properties. Component (C) is preferably a filler made of at least one material selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, carbon allotropes, resins, dyes, and pigments. Examples of fillers include metals such as aluminum, silver, copper, and metallic silicon; metal oxides such as alumina, zinc oxide, magnesium oxide, silicon dioxide, cerium oxide, and iron oxide; metal hydroxides such as aluminum hydroxide and cerium hydroxide; metal nitrides such as aluminum nitride and boron nitride; metal carbides such as silicon carbide; diamond, graphite, and carbon nanotubes. Examples of suitable materials include carbon allotropes such as graphene, tubes, and graphene; resins such as silicone resin powder; dyes such as indigo; and pigments such as red iron oxide. In order to impart thermal conductivity to the composition, it is preferable to use aluminum, silver, alumina, zinc oxide, and aluminum nitride. In order to impart heat resistance, it is preferable to use cerium oxide, cerium hydroxide, and iron oxide. In order to impart reinforcement, it is preferable to use silicon dioxide such as hydrophobic fumed silica. In order to impart conductivity, it is preferable to use silver, copper, and carbon allotropes. In order to impart smoothness, it is preferable to use silicone resin powder. In order to impart design properties, it is preferable to use dyes and pigments such as indigo and red iron oxide.

[0054] The average particle size of the filler is preferably 500 μm or less, more preferably 300 μm or less, and even more preferably 150 μm or less, since the resulting composition becomes more uniform if the average particle size is less than 500 μm. It is also preferably 0.01 μm or more, particularly preferably 0.1 μm or more. The average particle size can be determined, for example, as the volume average value (or median diameter) in particle size distribution measurement using laser diffraction. The shape of the filler is not particularly limited and may be spherical, irregular, acicular, plate-like, or the like.

[0055] The amount of component (C) blended is preferably in the range of 5,000 parts by mass or less, and more preferably 2,000 parts by mass or less, per 100 parts by mass of component (A), because the viscosity is not too high and the composition is easy to handle and homogeneous. If component (C) is blended, the amount is preferably 0.1 part by mass or more, and particularly preferably 1 part by mass or more.

[0056] [Component (D)] The curable silicone composition of the present invention may further contain a component (D) other than the components (A) to (C) above, as needed. For example, a non-reactive organo(poly)siloxane such as methylpolysiloxane may be added to adjust the strength and viscosity of the composition. Furthermore, hydrolyzable organopolysiloxanes, various modified silicones, and hydrolyzable organosilanes may be added to improve the filler loading or to impart adhesive properties to the composition. Furthermore, a solvent may be added to adjust the viscosity of the composition. Furthermore, a conventionally known antioxidant, such as 2,6-di-tert-butyl-4-methylphenol, may be added as needed to prevent deterioration of the curable silicone composition. Furthermore, a flame retardant, an anti-settling agent, a thixotropy improver, or the like may be added as needed.

[0057] [Method for Producing Silicone Composition] The method for producing the curable silicone composition of the present invention will be described. The method for producing the curable silicone composition of the present invention is not particularly limited, but may include producing a silicone composition comprising (A) an organopolysiloxane compound having a substituent group represented by the following general formula (1) in the molecule, (In the formula, R １ are independently a substituted or unsubstituted monovalent hydrocarbon group or a hydrogen atom, R ２ are independently substituted or unsubstituted divalent hydrocarbon groups, R ３ is a divalent linking group. ), and (B): an effective amount of a metal compound capable of catalyzing a [2+2+2] cycloaddition reaction. That is, the method comprises a step of mixing the above-mentioned components (A) and (B), and, if necessary, the curable silicone composition containing the components (C) and other components.

[0058] The above-mentioned components (A) and (B), and optionally also component (C) and other components, are mixed using a mixer such as ATAWATORI MIXER (registered trademark of THINKY CORPORATION), TRIMIX, TWINMIX, or PLANETARY MIXER (all registered trademarks of mixers manufactured by Inoue Seisakusho Co., Ltd.), ULTRA MIXER (registered trademarks of mixers manufactured by Mizuho Kogyo Co., Ltd.), or HIBISU DISPERMIX (registered trademarks of mixers manufactured by Tokushu Kika Kogyo Co., Ltd.), or by hand mixing using a spatula or the like at 25°C for typically 3 minutes to 24 hours, preferably 5 minutes to 12 hours, and particularly preferably 10 minutes to 6 hours. Deaeration may be performed during mixing.

[0059] The curable silicone composition of the present invention preferably has an absolute viscosity measured at 25°C of 0.1 to 1,000 Pa·s, more preferably 1 to 700 Pa·s, and even more preferably 5 to 500 Pa·s. A viscosity of 0.1 Pa·s or higher improves workability, such as good shape retention. A viscosity of 1,000 Pa·s or lower improves workability, such as easy discharge and application. The above viscosity can be obtained by adjusting the blend of the above-mentioned components. In the present invention, the absolute viscosity is the value measured at 25°C using a Malcolm viscometer (rotor A at 10 rpm, shear rate 6 [1 / s]).

[0060] [Cured Silicone Product] The cured silicone product of the present invention is obtained by curing the curable silicone composition described above. The method for producing this cured silicone product comprises: (A) 100 parts by mass of an organopolysiloxane compound having a substituent group represented by the following general formula (1) in the molecule; (In the formula, R １ are independently a substituted or unsubstituted monovalent hydrocarbon group or a hydrogen atom, R ２ are independently substituted or unsubstituted divalent hydrocarbon groups, R ３ is a divalent linking group.) and (B) an effective amount of a metal compound capable of catalyzing a [2+2+2] cycloaddition reaction; and curing the resulting mixture.

[0061] The method for curing the curable silicone composition described above comprises: (A) 100 parts by mass of an organopolysiloxane compound having a substituent group represented by the following general formula (1) in the molecule; (In the formula, R １ are independently a substituted or unsubstituted monovalent hydrocarbon group or a hydrogen atom, R ２ are independently substituted or unsubstituted divalent hydrocarbon groups, R ３ is a divalent linking group, and (B) an effective amount of a metal compound capable of catalyzing a [2+2+2] cycloaddition reaction is cured.

[0062] The curing conditions for curing the curable silicone composition of the present invention are not particularly limited, but the temperature is typically 0 to 200°C, preferably 10 to 150°C, and particularly preferably 20 to 100°C, and the curing time is typically 3 minutes to 72 hours, preferably 5 minutes to 48 hours, and particularly preferably 10 minutes to 24 hours. The state of the curable silicone composition after curing is not particularly limited, and examples include gel, low-hardness rubber, and high-hardness rubber. In this regard, Japanese Patent Laid-Open Publication No. 2015-93958 discloses an organopolysiloxane composition containing an organopolysiloxane containing an amic acid structure with a carbon-carbon triple bond and a non-platinum catalyst that promotes a trimerization cycloreaction. While the publication describes the composition as being heat-curable, high temperatures of 150 to 250°C are required for curing, and further heating to 250°C is required to convert the amic acid structure to a phthalimide structure. Because of these high-temperature curing characteristics, there is the problem that the composition cannot be applied to compositions containing heat-sensitive components that cannot be exposed to high temperatures during mounting. In contrast, the organopolysiloxane compound (A) of the curable silicone composition of the present invention does not have an amic acid structure and can provide a silicone composition that can be cured at lower temperatures, particularly under mild conditions of 100°C or less, and therefore has the advantage of being able to be cured even when heat-sensitive components are used.

[0063] The silicone cured product of the present invention is an elastic material, and since the silicone itself has excellent heat resistance and chemical resistance, it is useful as a silicone elastomer used as a coating agent, sealing agent, or encapsulant for semiconductor elements.

[0064] The curable silicone composition of the present invention is a liquid silicone composition during use, and can be cured under mild conditions in the presence of a catalyst to produce a silicone elastomer. The present invention employs a [2+2+2] cycloaddition reaction of alkynes, which uses a metal catalyst to form carbon-carbon bonds between multiple bonds. The [2+2+2] cycloaddition reaction forms an aromatic ring from three triple bonds, and is a highly useful reaction that produces no gas by-products during the reaction. The present invention is the first practical example of applying this reaction to organopolysiloxane compounds and their cured products. Furthermore, by appropriately selecting the catalyst, it is possible to achieve both the desired workability and curing characteristics.

[0065] In particular, the composition of the present invention cures via a catalytic [2+2+2] cycloaddition reaction, which provides superior curability and yields cured products with better properties than conventional radical-based addition reactions, hydrosilylation-based addition reactions, and condensation reactions. Specifically, the composition exhibits the following unprecedented curing properties: (I) unlike radical addition reactions, high temperatures are not required for the generation of initiating species, and the composition can be cured at room temperature or by heating. It is also resistant to curing inhibition by oxygen, resulting in excellent surface curability; (II) the composition has a different addition reaction mechanism from hydrosilylation, making it less susceptible to curing defects even when contaminated with or comes into contact with sulfur, phosphorus, nitrogen compounds, water, organometallic salts, and the like; and (III) unlike condensation reactions, the composition can be cured at room temperature without the use of moisture in the air, and does not generate gas or cause volumetric shrinkage during curing, resulting in excellent deep curing.

[0066] The curable silicone composition of the present invention can be cured under mild conditions of 100°C or below, even when using a catalyst that is stable at room temperature, and therefore can be cured even when using heat-sensitive parts that cannot be exposed to high temperatures during mounting, making it highly useful as a material used in the periphery of electric and electronic parts and semiconductor elements. If a highly active catalyst is used, smooth curing can be achieved even under milder conditions.

[0067] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following, the kinematic viscosity at 25°C is a value measured as described above, the catalyst concentration is a mass-based value converted into the central metal atom relative to the entire composition, the average particle size is a volume-based average value obtained by measuring particle size distribution using a laser diffraction method, and in the structural formulas described in the examples, Me represents a methyl group.

[0068] First, the following components were prepared to prepare the curable silicone composition of the present invention.

[0069] Component (A) A-1: ​​A component having a kinematic viscosity of 450 mm at 25°C, as shown in the following formula (3): ２ / s organopolysiloxane A-2: A viscosity at 25°C of 80 mm, as shown in the following formula (4): ２ / s A-3: A viscosity at 25°C of 140 mm as shown in the following formula (5) ２ / s a-4 (for comparison): Both ends are capped with ethynyl groups, and the kinematic viscosity at 25°C is 600 mm ２ / s dimethylpolysiloxane (not corresponding to component (A) of the present invention)

[0070] Component (B) B-1: A solution of tris(dibenzylideneacetone)dipalladium(0) dissolved in methylene chloride (catalyst concentration: 1% by mass) B-2: A solution of tris(dibenzylideneacetone)dipalladium(0) capped at both ends with trimethylsilyl groups and having a kinematic viscosity of 50,000 mm at 25°C ２ / s solution dissolved in dimethylpolysiloxane (catalyst concentration: 5 mass%)

[0071] Component (C) C-1: Aluminum oxide powder with an average particle size of 10 μm C-2: Zinc oxide powder with an average particle size of 0.4 μm

[0072] Component (D) D-1: Hydrolyzable organosilane represented by the following formula (6):

[0073] [Examples 1 to 8, Comparative Examples 1 to 4] Preparation of Curable Silicone Compositions [1] Curable silicone compositions were prepared by manually mixing the components (A) and (B) using a spatula in the amounts shown in Table 1 below. The properties of the resulting silicone compositions were confirmed when they were cured under the temperature conditions shown in Tables 1 and 2 below. The results are shown in Tables 1 and 2.

[0074]

[0075]

[0076] The above results indicate that the silicone compositions of Examples 1 to 8 of the present invention can be cured to a rubber-like state in as little as 0.5 hours at high temperatures of 100°C or higher, and within 48 hours at relatively low temperatures below 100°C. Comparative Example 1 demonstrates that the organopolysiloxane compounds satisfying the requirements of the present invention are not organopolysiloxane compounds that can be cured alone, since they do not cure without a metal catalyst that catalyzes the [2+2+2] cycloaddition reaction. Comparative Examples 2 to 4 are silicone compositions that use a dimethylpolysiloxane capped at both ends with ethynyl groups. These comparative compositions can be cured to a rubber-like state by heating at a high temperature of 150°C, but remain liquid even after 168 hours or more at a relatively low temperature of 25°C, demonstrating poor curability at room temperature. Therefore, it is clear that the organopolysiloxane compounds of the present invention can be cured to a rubber-like state by incorporating a metal catalyst that can catalyze the [2+2+2] cycloaddition reaction, and that they can be cured not only at high temperatures of 100°C or higher, but also at relatively low temperatures below 100°C.

[0077] Examples 9 to 13, Comparative Example 5 Preparation of Curable Silicone Compositions [2] Curable silicone compositions were prepared by mixing the components (A), (B), (C), and (D) in the amounts shown in Table 3 below using a Thinky Mixer. The properties of each of the resulting curable silicone compositions were confirmed when cured under the temperature conditions shown in Table 3 below. The results are shown in Table 3.

[0078]

[0079] The above results demonstrate that the silicone compositions of Examples 9 to 13 of the present invention can be cured to a rubber-like state in as little as 0.5 hours at high temperatures of 100°C or higher, and within 24 hours at relatively low temperatures below 100°C. Comparative Example 5 is a silicone composition using a dimethylpolysiloxane capped at both ends with ethynyl groups. This composition remains liquid even after 168 hours or more at the relatively low temperature of 25°C, demonstrating poor curability at room temperature. Therefore, it is clear that the organopolysiloxane compounds of the present invention, even when containing a large amount of filler, can be cured to a rubber-like state by incorporating a metal catalyst capable of catalyzing the [2+2+2] cycloaddition reaction, and that they can be cured not only at high temperatures above 100°C, but also at relatively low temperatures below 100°C.

[0080] This specification encompasses the following aspects: [1]: A curable silicone composition comprising: (A) 100 parts by mass of an organopolysiloxane compound having a substituent group represented by the following general formula (1) in the molecule; (In the formula, R １ are independently a substituted or unsubstituted monovalent hydrocarbon group or a hydrogen atom, R ２ are independently substituted or unsubstituted divalent hydrocarbon groups, R ３ is a divalent linking group, and (B) an effective amount of a metal compound capable of catalyzing a [2+2+2] cycloaddition reaction. [2]: R in the general formula (1) ２ [3]: The curable silicone composition according to [1], wherein R in the general formula (1) is a methylene group. １is a hydrogen atom. [4]: ​​The curable silicone composition of any one of [1] to [3], wherein component (A) is an organopolysiloxane compound having, on average, two or more substituents represented by general formula (1) per molecule. [5]: The curable silicone composition of any one of [1] to [4], further comprising (C) one or more inorganic or organic fillers in an amount of 0.1 to 5,000 parts by mass per 100 parts by mass of component (A). [6]: The curable silicone composition of [5], wherein component (C) is a filler composed of one or more materials selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, carbon allotropes, resins, dyes, and pigments. [7]: A silicone cured product obtained by curing the curable silicone composition of any one of [1] to [6]. [8]: A method for producing a curable silicone composition, comprising: (A) 100 parts by mass of an organopolysiloxane compound having a substituent group represented by the following general formula (1) in the molecule; (In the formula, R １ are independently a substituted or unsubstituted monovalent hydrocarbon group or a hydrogen atom, R ２ are independently substituted or unsubstituted divalent hydrocarbon groups, R ３ is a divalent linking group, and (B) an effective amount of a metal compound capable of catalyzing a [2+2+2] cycloaddition reaction.

[0081] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. A curable silicone composition comprising: (A) 100 parts by mass of an organopolysiloxane compound having a substituent in the molecule represented by the following general formula (1): (In the formula, R １ are independently a substituted or unsubstituted monovalent hydrocarbon group or a hydrogen atom; R ２ are independently substituted or unsubstituted divalent hydrocarbon groups; R ３ is a divalent linking group; and (B) an effective amount of a metal compound capable of catalyzing a [2+2+2] cycloaddition reaction.

2. R in the general formula (1) ２ 2. The curable silicone composition according to claim 1, wherein is a methylene group.

3. R ​​in the general formula (1) １ 2. The curable silicone composition according to claim 1, wherein: is a hydrogen atom.

4. The curable silicone composition according to claim 1, wherein the component (A) is an organopolysiloxane compound having, on average, two or more substituents represented by the general formula (1) per molecule.

5. A curable silicone composition according to any one of claims 1 to 4, further comprising (C) one or more inorganic or organic fillers in an amount of 0.1 to 5,000 parts by mass per 100 parts by mass of component (A).

6. The curable silicone composition according to claim 5, wherein component (C) is a filler made of one or more materials selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, carbon allotropes, resins, dyes, and pigments.

7. A silicone cured product obtained by curing the curable silicone composition according to any one of claims 1 to 4.

8. A silicone cured product obtained by curing the curable silicone composition according to claim 5.

9. A method for producing a curable silicone composition, comprising: (A) 100 parts by mass of an organopolysiloxane compound having a substituent represented by the following general formula (1) in the molecule; (In the formula, R １ are independently a substituted or unsubstituted monovalent hydrocarbon group or a hydrogen atom; R ２ are independently substituted or unsubstituted divalent hydrocarbon groups; R ３ is a divalent linking group; and (B) an effective amount of a metal compound capable of catalyzing a [2+2+2] cycloaddition reaction.

Images