Curable silicone composition, method for producing the same and curing method, cured silicone product and method for producing the same, and [2+2+2] cycloaddition reaction product and method for producing the same

Abstract

To provide a curable type silicone composition that can reduce environmental impact by not requiring special temperature control during storage or transportation and that is less susceptible to the effect of a substance that causes cure inhibition to conventionally known addition-curable type silicone compositions.SOLUTION: Provided is a curable type silicone composition and that is characterized by containing (A) an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule: 100 pts.mass and (B) a transition metal compound, typical metal compound or combination thereof capable of catalyzing [2+2+2] cycloaddition reaction: an effective amount.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable silicone composition, a cured silicone product, a method for producing a curable silicone composition, a method for producing a cured silicone product, a method for curing a curable silicone composition, a [2+2+2] cycloaddition reaction product, and a method for producing a [2+2+2] cycloaddition reaction product. [Background technology]

[0002] Curable silicone compositions harden to form silicone gels, silicone rubbers, hard coat films, etc., which have excellent electrical properties, cold resistance, heat resistance, and chemical stability. Therefore, they are widely used as encapsulants, fillers, or coatings for electrical and electronic components and semiconductor devices, as well as as insulating coatings and protective agents for optoelectronic semiconductors. Furthermore, by incorporating various fillers, it is possible to increase the strength of the composition or impart heat resistance. They are also utilized as heat dissipation and conductive materials for electronic components such as semiconductor devices and LED substrates. In recent years, against the backdrop of growing momentum toward carbon neutrality, there has been a demand for curable silicone compositions that can reduce environmental impact by not requiring special temperature control during storage or transportation.

[0003] Curing methods for curable silicone compositions can be broadly classified into three types: "addition curing," "condensation curing," and "peroxide curing." Addition-curing silicone compositions generally have poor storage properties at room temperature, requiring freezing or refrigerated storage and transportation. While a two-component curing type, with the catalyst and crosslinking agent components separated, allows for room temperature storage and transportation, it is essential to introduce equipment for accurately and uniformly mixing the two components. Furthermore, while using a UV-activated catalyst instead of a conventional temperature-responsive catalyst allows for room temperature storage and transportation under light-shielding conditions, it is essential to introduce equipment for UV irradiation to cure the composition. In addition, regardless of whether it is a one-component or two-component curing type, or whether the catalyst is temperature-responsive or UV-activated, the catalyst component may be deactivated by amine compounds contained in cutting oils, epoxy molding materials, etc., which can lead to curing failures.

[0004] Condensation-curing silicone compositions harden due to moisture in the air, allowing for room temperature storage and transport if moisture is blocked. However, they produce low-boiling-point desorbed components during the curing reaction, which is undesirable from an environmental perspective. Furthermore, due to the curing system that utilizes moisture in the air, they suffer from poor deep curing properties.

[0005] While peroxide-curable silicone compositions can be stored and transported at room temperature by selecting an appropriate peroxide catalyst, they face the challenge of curing inhibition by oxygen in the air.

[0006] While a one-component addition-curing silicone composition is deemed most suitable considering its curability and handling properties, as mentioned above, it is difficult to store and transport at room temperature. One way to improve the room-temperature storage of a one-component addition-curing silicone composition is to incorporate an appropriate amount of an addition-curing reaction control agent, such as acetylene alcohol (Patent Document 1). However, if these addition-curing reaction control agents are incorporated to the extent that room-temperature storage and transport are possible, the curing reaction does not proceed sufficiently in the subsequent curing process of the addition-curing silicone composition, leading to curing failure.

[0007] Another approach, for example, is to use a microcapsule structure in which the catalyst component is embedded in a polymer compound (e.g., Patent Documents 2 and 3). However, the catalyst component embedded inside the microcapsule structure has a slow diffusion rate into the composition, making it difficult to initiate the addition curing reaction. As a result, the curing reaction may not proceed sufficiently during the curing process, potentially leading to curing failure.

[0008] An addition-curable silicone composition may contain a compound having a carbon-carbon triple bond as a curing retarder (reaction controller). The curing retarder not only controls the reaction rate of the addition reaction (hydrosilylation) to extend the pot life of the addition-curable silicone composition, but also has the function of preventing a part of the silicone composition from starting to cure during work because the curing of the silicone composition is too fast. On the other hand, in Patent Document 4, a substituted polyacetylene compound is obtained by polymerizing an organosilicon compound having a carbon-carbon triple bond in the presence of a catalyst. A compound having a carbon-carbon triple bond can polymerize to give a linear polymer as described above, and can also undergo a cycloaddition reaction to give a hyperbranched polymer which is a polymer having a multi-branched structure (Patent Documents 5 and 6). Further, Non-Patent Document 1 describes that an alkyne and a nitrile undergo a [2+2+2] cycloaddition reaction to give a cyclic compound such as pyridine.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Non-Patent Documents

[0010]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0011] As described above, various studies have been conducted on the curing of curable silicone compositions, and further improvements are needed from the viewpoint of reducing environmental impact and improving workability. Considering curability and handling, one-component addition-curing silicone compositions are preferable, but even then, good storage at room temperature and a good curing reaction have not been achieved simultaneously. In other words, conventional addition-curing silicone compositions have problems such as the difficulty in reducing environmental impact due to the need for temperature control, and susceptibility to curing inhibitors such as amine compounds contained in cutting oils and epoxy molding materials. Furthermore, while compounds containing carbon-carbon triple bonds undergo addition reactions to form polymers, the [2+2+2] cycloaddition reaction of organopolysiloxanes containing triple bonds has not been previously known.

[0012] Accordingly, the present invention has been made in view of the above circumstances, and aims to provide a curable silicone composition that can reduce environmental impact by not requiring special temperature control during storage or transportation, and that is less susceptible to the influence of substances that cause curing inhibition compared to conventionally known addition-curing silicone compositions. Furthermore, the present invention aims to provide a [2+2+2] cycloaddition reaction product of an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule, which is a novel substance, and a method for producing the same. [Means for solving the problem]

[0013] To solve the above problems, the present invention provides a curable silicone composition, (A) Organopolysiloxane having at least one alkynyl group or nitrile group in one molecule: 100 parts by mass, (B) Transition metal compounds, typical metal compounds, or combinations thereof capable of catalyzing [2+2+2] cycloaddition reactions: effective amount, The present invention provides a curable silicone composition characterized by containing the following:

[0014] Such a curable silicone composition does not require special temperature control during storage or transportation, thereby reducing the environmental impact, and is less susceptible to substances that inhibit curing compared to conventionally known addition-curing silicone compositions.

[0015] In this invention, the kinematic viscosity of component (A) at 25°C is 1 to 20,000,000 mm². 2 It is preferable that the organopolysiloxane is of type / s.

[0016] The above kinematic viscosity is 1 mm 2 If the temperature is 20,000,000 mm² or higher, the physical properties of the curable silicone composition are good, and the temperature is 20,000,000 mm². 2 If the value is less than or equal to / s, the spreadability of the curable silicone composition will be sufficient.

[0017] In the present invention, component (A) is preferably an organopolysiloxane having at least one alkynyl group in one molecule, and more preferably an organopolysiloxane having at least one ethynyl group in one molecule.

[0018] Such organopolysiloxanes are preferred as component (A).

[0019] In the present invention, it is preferable that component (B) is a transition metal complex capable of catalyzing a [2+2+2] cycloaddition reaction.

[0020] As for component (B), such transition metal complexes are suitable as catalysts for the [2+2+2] cycloaddition reaction.

[0021] In the present invention, it is preferable that (C) at least one inorganic or organic filler is included in an amount of 0.1 to 5,000 parts by mass per 100 parts by mass of component (A).

[0022] Such 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. If the amount added is within the above range, the viscosity is not too high, making it easy to handle and resulting in a uniform composition.

[0023] In this case, it is preferable that 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, allotropes of carbon, resins, dyes, and pigments.

[0024] By selecting such materials and using them as fillers, properties such as thermal conductivity, heat resistance, reinforcement, electrical conductivity, smoothness, and aesthetic appeal can be imparted to the composition.

[0025] Furthermore, the present invention provides a cured silicone product obtained by curing the above-mentioned curable silicone composition.

[0026] The silicone cured product of the present invention exhibits excellent electrical properties, cold resistance, heat resistance, and chemical stability, and is widely used in the form of silicone gel, silicone rubber, hard coat film, etc., as a encapsulant, filler, or coating agent for electrical and electronic components and semiconductor elements, as well as an insulating coating protective material for optical semiconductors. Furthermore, by including various fillers, it is possible to increase strength or impart heat resistance. Moreover, it can be used as a heat dissipation material or conductive material for electronic components such as semiconductor elements and LED substrates.

[0027] Furthermore, the present invention relates to a method for producing a curable silicone composition, (A) Organopolysiloxane having at least one alkynyl group or nitrile group in one molecule: 100 parts by mass, (B) Transition metal compounds, typical metal compounds, or combinations thereof capable of catalyzing [2+2+2] cycloaddition reactions: effective amount, The present invention provides a method for producing a curable silicone composition, characterized by mixing [a certain substance].

[0028] The method for producing the curable silicone composition of the present invention allows for the efficient production of the above-mentioned curable silicone composition.

[0029] Furthermore, the present invention relates to a method for producing a silicone cured product, (A) Organopolysiloxane having at least one alkynyl group or nitrile group in one molecule: 100 parts by mass, (B) Transition metal compounds, typical metal compounds, or combinations thereof capable of catalyzing [2+2+2] cycloaddition reactions: effective amount, The present invention provides a method for producing a cured silicone product, characterized by comprising the steps of mixing and curing the resulting mixture.

[0030] Furthermore, the present invention relates to a method for curing a curable silicone composition, (A) An organopolysiloxane having at least one alkynyl group or nitrile group in one molecule, (B) A method for curing a curable silicone composition is provided, characterized by curing a mixture containing an effective amount of a transition metal compound, a typical metal compound, or a combination thereof that can catalyze a [2+2+2] cycloaddition reaction.

[0031] In this way, the above-mentioned curable silicone composition can be suitably cured, and the cured silicone product can be manufactured efficiently.

[0032] Furthermore, the present invention provides a [2+2+2] cycloaddition reaction product of an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule.

[0033] The [2+2+2] cycloaddition reaction product of the present invention does not require special temperature control during storage or transportation, thus reducing the environmental burden. Furthermore, it is less susceptible to substances that inhibit curing, making it an excellent main component of curable silicone compositions.

[0034] Furthermore, the present invention provides a method for producing a [2+2+2] cycloaddition reaction product, characterized in that (A) an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule is subjected to a [2+2+2] cycloaddition reaction using (B) a transition metal compound, a typical metal compound, or a combination thereof capable of catalyzing a [2+2+2] cycloaddition reaction to obtain the product.

[0035] The present invention's method for producing [2+2+2] cycloaddition reaction products allows for the efficient production of [2+2+2] cycloaddition reaction products from organopolysiloxanes having alkynyl groups or nitrile groups. [Effects of the Invention]

[0036] The curable silicone composition of the present invention utilizes an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule, and a transition metal compound, a typical metal compound, or a combination thereof capable of catalyzing a [2+2+2] cycloaddition reaction. This allows for storage and transport at room temperature and has the advantage of being less susceptible to substances that inhibit curing compared to conventionally known addition-curable silicone compositions. As a result, environmental impact can be reduced by eliminating the need for special temperature control during storage and transport. Furthermore, even if substances that inhibit curing are present in conventionally known addition-curable silicone compositions, the curing reaction is not inhibited in the present invention. Therefore, the curable silicone composition of the present invention can be applied to areas containing curing-inhibiting substances such as amine compounds, cutting oils, and epoxy molding materials. [Modes for carrying out the invention]

[0037] As mentioned above, there has been a need to develop an addition-curing silicone composition that does not require special temperature control during storage or transportation, and is less susceptible to substances that inhibit curing compared to conventional addition-curing silicone compositions.

[0038] As a result of diligent research into the above-mentioned problems, the present inventors have discovered that when an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule is combined with a catalyst active in a [2+2+2] cycloaddition reaction, the organopolysiloxane can be cured even if substances that cause curing inhibition in conventional addition-curing silicone compositions are present, and that special temperature control is not required during storage or transportation. Thus, the present invention was completed.

[0039] In other words, the present invention is a curable silicone composition, (A) Organopolysiloxane having at least one alkynyl group or nitrile group in one molecule: 100 parts by mass, (B) Transition metal compounds, typical metal compounds, or combinations thereof capable of catalyzing [2+2+2] cycloaddition reactions: effective amount, This is a curable silicone composition characterized by containing [a specific ingredient].

[0040] The present invention will be described in detail below, but the present invention is not limited to these descriptions.

[0041] This invention relates to a curable silicone composition. More specifically, it relates to a curable silicone composition that can be stored and transported at room temperature and is less susceptible to substances that cause curing inhibition compared to conventionally known addition-curing silicone compositions.

[0042] [Curing silicone composition] The curable silicone composition of the present invention is characterized by comprising (A) 100 parts by mass of an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule, and (B) an effective amount of a transition metal compound, a typical metal compound, or a combination thereof capable of catalyzing a [2+2+2] cycloaddition reaction. The above curable silicone composition comprises components (A) and (B), and may further contain, if necessary, other components such as component (C) (inorganic or organic filler) or components for adjusting the strength and viscosity of the composition, as described later.

[0043] In this invention, an organopolysiloxane having an alkynyl group or a nitrile group undergoes a catalytic [2+2+2] cycloaddition reaction. The [2+2+2] cycloaddition referred to here is a process in which, for example, a carbon-carbon triple bond is cyclized to form a six-membered ring, as shown below, to create a benzene skeleton. In the following formula, R represents an organic group. [ka] Furthermore, if a carbon-nitrogen triple bond (cyano group) is used instead of a carbon-carbon triple bond in the above formula, a corresponding heterocyclic skeleton such as a pyridine ring is formed. The components included in the curable silicone composition of the present invention will be described below.

[0044] (A) component (A) Component is an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule.

[0045] The alkynyl group is preferably a monovalent hydrocarbon group having 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, having a carbon-carbon triple bond. Examples include terminal alkynes such as ethynyl and propagyl groups, and internal alkynes having a group other than a hydrogen atom on the carbon atom forming the carbon-carbon triple bond. Preferably a terminal alkyne, and particularly preferably an ethynyl group. The nitrile group is preferably a monovalent hydrocarbon group having a carbon-nitrogen triple bond, having 2 to 8 carbon atoms. 1 ~8, more preferably the number of carbon atoms 1 It is a monovalent functional group of ~6. Examples include a cyano group, a cyanomethyl group, a cyanoethyl group, etc., and a cyano group is preferred.

[0046] The alkynyl group or nitrile group may be bonded to either a silicon atom at the end of the molecular chain, a silicon atom in the middle of the molecular chain, or both.

[0047] The organic groups other than alkynyl or nitrile groups bonded to the silicon atoms of the organopolysiloxane are unsubstituted or substituted monovalent hydrocarbon groups having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms. For example, alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl groups; aryl groups such as phenyl, tolyl, xylyl, and naphthyl groups; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl groups; or halogenated elements such as fluorine, bromine, and chlorine, which are used to bond some or all of the hydrogen atoms of these groups. children etc. Substituted with, for example, chloromethyl group, chloropropyl group, bromoethyl group, trifluoropropyl Moto etc. These include, in particular, methyl groups and trifluoropropyl groups.

[0048] The organopolysiloxane has a kinematic viscosity of 1 to 20,000,000 mm² at 25°C. 2 / s, preferably 10 to 1,000,000 mm 2 / s, more preferably 60-30,000 mm 2 The kinematic viscosity is 1 mm³ / s. 2 If the temperature is 20,000,000 mm² or higher, the physical properties of the curable silicone composition are good, and the temperature is 20,000,000 mm². 2 If the value is less than or equal to / s, the spreadability of the curable silicone composition will be sufficient.

[0049] In this invention, the kinematic viscosity is the value measured at 25°C using an Ubbelohde-type Ostwald viscometer (the same applies hereinafter).

[0050] The organopolysiloxane described above is not particularly limited in its molecular structure as long as it possesses the above properties, and examples include linear structures, branched structures, partially branched structures, or linear structures having a cyclic structure. In particular, it is preferable that the main chain consists of repeating diorganosiloxane units and has a linear structure in which both ends of the molecular chain are sealed with triorganosiloxy groups. The organopolysiloxane having a linear structure may also have a partially branched or cyclic structure.

[0051] The organopolysiloxanes can be used individually or in combination of two or more.

[0052] (B) Component Component (B) is a transition metal compound, a main group metal compound, or a combination thereof that can catalyze a [2+2+2] cycloaddition reaction (e.g., Non-Patent Document 1), and is incorporated 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.

[0053] Examples of transition metal compounds that have catalytic activity for [2+2+2] cycloaddition reactions include the following:

[0054] Transition metal compounds can be composed of a central metal atom, ligands, and counterions. Examples of the central metal atom include those from Group 4 to Group 12. Specifically, Group 4 (titanium (Ti), zirconium (Zr), hafnium (Hf)), Group 5 (vanadium (V), niobium (Nb), tantalum (Ta)), Group 6 (chromium (Cr), molybdenum (Mo), tungsten (W)), Group 7 (manganese (Mn), rhenium (Re)), Group 8 (iron (Fe), ruthenium (Ru), osmium (Os)), Group 9 (cobalt (Co), rhodium (Rh), iridium (Ir)), Group 10 (nickel (Ni), palladium (Pd), platinum (Pt)), Group 11 (copper (Cu)), Group 12 (zinc (Zn)) can be mentioned. The central metal atom can be one type or two or more types. In the case of two or more types, they can all be the same metal or a combination of different metals.

[0055] The ligands are not particularly limited, and examples include carbonyl (CO), ammonia, water, F - , Cl - , Br - , I - and other halide ions, cyanide ions (CN - ), phosphines such as triphenylphosphine (PR3), cyclopentadienyl (Cp) groups, pentamethylcyclopentadienyl (Cp * ) groups, olefins such as cyclooctadiene (COD) groups, cyclooctatriene (COT) groups, norbornene groups, norbornadiene groups, α,β-unsaturated ketones such as dibenzylideneacetone, acyl groups such as acetyl groups and benzoyl groups, β-diketones such as acetylacetone (acac), β-ketoesters such as ethyl acetoacetate, amines such as alkylamines, alkylenediamines, aniline, pyridine, or alkoxy groups. Among them, carbonyl (CO), cyclopentadienyl (Cp) groups, triphenylphosphine, and dibenzylideneacetone are preferred. The ligands can be monodentate ligands or polydentate ligands with two or more coordination sites.

[0056] The counterions are not particularly limited and can include halide ions, cyanide ions, carbonates, and PF6, which can also act as ligands. - BF4 - NO3 - , BPh4 - ClO4 - Examples include anions such as ammonium, sulfonium, and onium cations such as phosphonium. Among these, halide ions are preferred, and Cl - This is preferable.

[0057] Transition metal compounds, MQ n In this representation, M is Ti, Nb, Ta, Fe, Ru, Co, Rh, Ir, Ni, or Pd, with Ti, Nb, Ta, Co, Rh, or Pd being preferred, and Co, Rh, or Pd being more preferred. Q is a cyclopentadienyl group, a halogen atom, an OAc group (Ac representing an acetyl group), an acetylacetonate group, or an alkoxy group. Examples of halogen atoms include I, Br, Cl, and F, with I, Br, and Cl being preferred. n is the number corresponding to the valency of M. MQ n In this case, two or more different types of Q may be included.

[0058] Transition metal complexes are MQ n Preferably, it contains a transition metal salt represented by or a complex of the hydrate thereof with ligand L, MQ n -L m The complex represented by MQ is also preferred. n The details are as described above. Ligand L can be 2-(2,6-diisopropylphenyl)iminomethylpyridine (dipimp), triphenylphosphine (PPh3), 1,2-bis(diphenylphosphin)ethane (dppe), 2,6-bis(2,6-diisopropylphenyliminomethyl)pyridine, or cyclooctadienyl (cod), etc. m is an integer. The transition metal complex may be mononuclear or dinuclear.

[0059] More specifically, transition metal salts include Ti(Oi-Pr) 4、Examples include CpTi(Oi-Pr)3, CpTiCl3, NbCl5, TaCl5, FeCl2, FeCl3, FeBr2, FeBr3, FeI2, FeI3, Fe(OAc)2, Fe(OAc)3, Fe(acac)2, Fe(acac)3, CoCl2, CoCl3, CoBr2, CoBr3, CoI2, CoI3, Co(OAc)2, Co(OAc)3, Co(acac)2, Co(acac)3, RhCl3, RuCl3, IrCl3, etc. i-Pr represents an isopropyl group, and acac represents an acetylacetonate group.

[0060] Catalysts obtained by reacting a transition metal salt or its hydrate selected from the above, or a complex of these transition metal salts or their hydrates (for example, a complex with the above-mentioned ligand L), with a reducing agent (for example, a reducing agent such as a metal, organometallic, metal hydride, or alkylamine described later) can also be used.

[0061] As for transition metal salts, CoQ a 2(Q a Salts represented by CoQ (where represents a cyclopentadienyl group, a halogen atom, an OAc group, or an acetylacetonate group) are also preferred. a A transition metal salt represented by 2 or its hydrate, or CoQ a Catalysts obtained by reacting a transition metal salt represented by 2 or a complex of its hydrate (for example, a complex with the above-mentioned ligand L) with a reducing agent (for example, a reducing agent such as a metal, organometallic, metal hydride, or alkylamine described later) can also be used.

[0062] Examples of reducing agents include metals (e.g., Zn, Mn, Al, Mg, etc.), organometallic compounds (e.g., Grignard reagents, organolithium compounds, etc.), metal hydrides (e.g., NaBH4, LiAlH4, etc.), and alkylamines (e.g., trialkylamines such as triethylamine). For metals such as Zn, Mn, Al, and Mg, powder form is preferred.

[0063] Examples of such transition metal complexes include [Mo(CO)3Cp]2, [W(CO)3Cp]2, Co2(CO)8, NbCl5, TaCl5, cyclopentadienylcobalt(I) dicarbonyl (CpCo(CO)2), tetrakis(triphenylphosphine)palladium(O), tris(dibenzylideneacetone)dipalladium(O), tris(triphenylphosphine)rhodium(I) chloride, and Pd(Ph3P)2Cl2-CuI. When CpCo(CO)2 is used, it can be activated by UV irradiation.

[0064] The transition metal complex may be used diluted by dissolving or dispersing it in a solvent as needed. Any known solvent may be used as such, 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 those with trimethylsilyl groups encapsulated at both ends and a kinematic viscosity of 50,000 mmHg at 25°C. 2 Examples of polysiloxanes include dimethylpolysiloxane ( / s).

[0065] Typical metal compounds that exhibit catalytic activity for [2+2+2] cycloaddition reactions include the following:

[0066] Typical metal compounds can be composed of a central metal atom, a ligand, and a counterion. Examples of central metal atoms include those from Group 13 and Group 14. Specifically, these include Group 13 (aluminum (Al), gallium (Ga), indium (In), thallium (Tl)) and Group 14 (tin (Sn), lead (Pb)). Examples of organometallic compounds of these metals include organoaluminum compounds such as triethylaluminum and organotin compounds such as Ph4Sn.

[0067] Typical metal compounds, like transition metal complexes, may be used after being diluted by dissolving or dispersing them in a solvent as needed. The solvents listed for transition metal complexes can be used for this purpose.

[0068] The concentration of the transition metal complex or typical metal compound in the solvent (catalyst concentration) can be set as needed. For example, it can be 0.01 to 10% by mass, preferably 0.1 to 5% by mass, based on the mass of the central metal. The desired composition can be prepared by adding the diluent in an amount corresponding to the amount of component (B) described later.

[0069] For component (B), conventionally known catalysts used in [2+2+2] cycloaddition reactions (disclosed in, for example, Patent Documents 5 and 6, and Non-Patent Document 1) can be used. Specifically, examples include transition metal compounds such as cobalt-based, palladium-based, rhodium-based, ruthenium-based, iron-based, titanium-based, zirconium / nickel-based, zirconium / copper-based, and tantalum-based catalysts, and typical metal compounds such as silicon-based and germanium-based catalysts. It is preferable that the catalyst is a transition metal compound capable of catalyzing the [2+2+2] cycloaddition reaction, and more preferably a transition metal complex. Among these, cobalt-based, palladium-based, rhodium-based, and ruthenium-based catalysts (transition metal complexes), which are relatively easy to obtain, are preferred. Component (B) may be used alone or in combination of two or more, or any combination of transition metal compounds and typical metal compounds. Examples include NbCl5-Ph4Sn and TaCl5-Ph4Sn. Here, "system" means "containing," for example, "cobalt-based" means containing cobalt, and "transition metal-based compound" means a compound containing a transition metal.

[0070] As the (B) component, which is an active catalyst for the [2+2+2] cycloaddition reaction, cyclopentadienylcobalt(I) dicarbonyl, tetrakis(triphenylphosphine)palladium(O), tris(dibenzylideneacetone)dipalladium(O), and tris(triphenylphosphine)rhodium(I) chloride are particularly preferred.

[0071] Transition metal compounds may be obtained by reacting a transition metal salt or its hydrate, or a complex of a transition metal salt or its hydrate, with a reducing agent. In this way, transition metals can be reduced and catalytically active species can be generated.

[0072] Reactions involving alkynyl groups include, for example, the catalytic synthesis of substituted polyacetylenes as described in Patent Document 4, and the formation of a benzene skeleton by cyclotrimerization of alkynyl groups. In relation to the latter, polymerization reactions using the cycloaddition trimerization reaction of alkynes ([2+2+2] cycloaddition reaction) as a bond formation reaction are expected to be a useful polymer synthesis method for producing branched polymers (hyperbranched polymers) (Patent Documents 5 and 6). Furthermore, it is known that heterocycles such as pyridine rings can be formed by catalytic [2+2+2] cycloaddition reactions between alkynyl groups and carbon-nitrogen triple bonds (cyano groups) or isocyanate groups (Non-Patent Document 1). Thus, while the application of [2+2+2] cycloaddition reactions to specific ring formation and branched polymer synthesis is known, its application to curing reactions has not been investigated until now.

[0073] This invention combines an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule with a catalyst active in a [2+2+2] cycloaddition reaction. This is based on the inventors' first discovery that silicone compositions can be cured by a reaction mechanism called [2+2+2] cycloaddition, which is completely different from conventional curing reactions (addition curing by hydrosilylation). Because this invention employs a curing reaction by [2+2+2] cycloaddition, the curing reaction proceeds even if a substance that inhibits curing is present in the addition-curing type silicone composition, and it has excellent features not found in conventional curing methods, such as not requiring a reaction control agent and not requiring special temperature control during storage or transportation. In the present invention, the curing reaction proceeds catalytically with an organopolysiloxane having an alkynyl group or a nitrile group undergoing a [2+2+2] cycloaddition reaction. As described above, [2+2+2] cycloaddition allows, for example, a carbon-carbon triple bond to trimerize and form a benzene skeleton, or a carbon-carbon triple bond to cyclize with a carbon-nitrogen triple bond (CN group) to form a heterocycle such as a pyridine ring. These cyclic skeletons formed in the curing reaction are planar and chemically stable structures. Therefore, the cured products obtained in the present invention are expected to have excellent electrical properties, cold resistance, heat resistance, and chemical stability.

[0074] The amount of component (B) should be an effective amount as a catalyst, that is, 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, based on the mass of the central metal atoms relative to the entire composition. If the amount of catalyst is above the lower limit, the catalytic effect will be obtained, and if it is below the upper limit, the catalytic effect will be sufficient and economical.

[0075] (C) Component The curable silicone composition of the present invention may further contain an inorganic or organic filler as component (C). Component (C) is used to impart various properties to the curable silicone composition of the present invention, such as thermal conductivity, heat resistance, reinforcement, electrical conductivity, and design properties. Preferably, the filler is made of at least one material selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, allotropes of carbon, resins, dyes, and pigments. Examples 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 nanoparticles. Examples include tubes, allotropes of carbon such as graphene, resins such as silicone resin powder, dyes such as indigo, and pigments such as red iron oxide. To impart thermal conductivity to the composition, aluminum, silver, alumina, zinc oxide, and aluminum nitride are preferred. To impart heat resistance, cerium oxide, cerium hydroxide, and iron oxide are preferred. To impart reinforcing properties, silicon dioxide such as hydrophobic fumed silica is preferred. To impart conductivity, silver, copper, and allotropes of carbon are preferred. To impart smoothness, silicone resin powder is preferred. To impart design appeal, dyes and pigments such as indigo and red iron oxide are preferred.

[0076] The average particle size of the filler is preferably in the range of 500 μm or less, more preferably in the range of 100 μm or less, and even more preferably in the range of 40 μm or less, as reducing it to less than 500 μm results in a more uniform composition. Furthermore, it is preferable that it be 0.01 μm or more, and particularly 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 by laser diffraction. The shape of the filler is not particularly limited and can be spherical, irregularly shaped, needle-shaped, plate-shaped, etc.

[0077] The amount of component (C) should be in the range of 5,000 parts by mass or less, preferably 2,000 parts by mass or less, per 100 parts by mass of component (A). This ensures that the viscosity is not too high, making it easy to handle and resulting in a uniform composition. When component (C) is added, it is preferable that the amount be 0.1 parts by mass or more, and particularly 1 part by mass or more.

[0078] Other ingredients The curable silicone composition of the present invention may contain non-reactive organo(poly)siloxanes such as methylpolysiloxane to adjust the strength and viscosity of the composition. Hydrolyzable organopolysiloxanes, various modified silicones, and hydrolyzable organosilanes may be added to improve the filling properties of the filler or to impart adhesion to the composition. Furthermore, solvents may be added to adjust the viscosity of the composition. In addition, conventionally known antioxidants such as 2,6-di-tert-butyl-4-methylphenol may be added as needed to prevent deterioration of the curable silicone composition. Furthermore, flame retardants, anti-settling agents, or thixotropic enhancers may be added as needed.

[0079] Method for preparing a curable silicone composition The method for producing the curable silicone composition according to the present invention will now be described. The method for producing the curable silicone composition according to the present invention is not particularly limited, but is characterized by mixing (A) 100 parts by mass of an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule, and (B) an effective amount of a transition metal compound, a typical metal compound, or a combination thereof capable of catalyzing a [2+2+2] cycloaddition reaction. In other words, the method involves mixing the above-mentioned components (A) and (B), and optionally adding component (C) or other components in addition to prepare a curable silicone composition.

[0080] The above-mentioned components (A) and (B), and optionally component (C) and other components, are mixed at 25°C for typically 3 minutes to 24 hours, preferably 5 minutes to 12 hours, and particularly preferably 10 minutes to 6 hours.

[0081] The curable silicone composition of the present invention has an absolute viscosity, measured at 25°C, preferably 0.1 to 1,000 Pa·s, more preferably 1 to 700 Pa·s, and even more preferably 5 to 500 Pa·s. When the viscosity is 0.1 Pa·s or higher, workability is improved, such as good shape retention. When the viscosity is 1,000 Pa·s or lower, workability is improved, such as easy dispensing and application. The above viscosity can be obtained by adjusting the blending of each component described above. 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]).

[0082] The curable silicone composition of the present invention can be suitably used in a wide range of applications, similar to conventional general curable silicone compositions, and is particularly effective for applications that do not require special temperature control during storage or transportation, and for applications where substances that cause curing inhibition in conventionally known addition-curing silicone compositions are present.

[0083] [Cured silicone product] The silicone cured product of the present invention is obtained by curing the above-mentioned curable silicone composition. The method for producing this silicone cured product is characterized by comprising the steps of: mixing (A) 100 parts by mass of an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule, and (B) an effective amount of a transition metal compound, a typical metal compound, or a combination thereof capable of catalyzing a [2+2+2] cycloaddition reaction, and curing the resulting mixture. Furthermore, the curing method for the above-mentioned curable silicone composition is characterized by curing a mixture containing (A) an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule, and (B) an effective amount of a transition metal compound, a typical metal compound, or a combination thereof capable of catalyzing a [2+2+2] cycloaddition reaction.

[0084] The curing conditions for curing the curable silicone composition of the present invention are not particularly limited, but the temperature is usually 25 to 200°C, preferably 60 to 180°C, and particularly preferably 80 to 170°C, and the curing time is usually 3 minutes to 24 hours, preferably 5 minutes to 12 hours, and particularly preferably 10 minutes to 6 hours. The properties of the curable silicone composition after curing are not particularly limited and include gel-like, low-hardness rubber-like, high-hardness rubber-like, etc.

[0085] [[2+2+2] Cycloaddition reaction product] The present invention provides a [2+2+2] cycloaddition reaction product of an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule. The above method for producing the [2+2+2] cycloaddition reaction product is characterized by obtaining the product by (A) an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule, and (B) a transition metal compound, a typical metal compound, or a combination thereof capable of catalyzing the [2+2+2] cycloaddition reaction. The structure of the [2+2+2] cycloaddition reaction product (silicone cured product) can be confirmed by known measurement methods such as nuclear magnetic resonance spectroscopy, infrared spectroscopy, and gel permeation chromatography. [Examples]

[0086] 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 the value measured as described above, the catalyst concentration is based on the mass of the central metal atom relative to the entire composition, and the average particle size is the volume-based average value obtained from particle size distribution measurement by laser diffraction. Furthermore, the structure of the obtained silicone cured product was confirmed by nuclear magnetic resonance spectroscopy, infrared spectroscopy, and gel permeation chromatography.

[0087] First, the following components were prepared to create the curable silicone composition of the present invention.

[0088] (A) component A-1: Both ends are sealed with ethynyl groups, and the kinematic viscosity at 25°C is 600 mmHg. 2 / s Dimethylpolysiloxane A-2: Both ends are sealed with ethynyl groups, and the kinematic viscosity at 25°C is 900 mmHg. 2 / s Dimethylpolysiloxane A-3:M E 5T 10 (Kinematic viscosity at 25°C is 15 mm 2 / s) (M E HC≡CMe2SiO 1 / 2 T is MeSiO 3 / 2 (is) A-4: The kinematic viscosity at 25°C is 500 mm², as shown in formula (1) below. 2 / s organopolysiloxane [ka] A-5 (for comparison): Both ends are sealed with vinyl groups, and the kinematic viscosity at 25°C is 600 mmHg. 2 / s Dimethylpolysiloxane

[0089] (B) Component B-1: Cyclopentadienylcobalt(I)dicarbonyl B-2: Solution of tetrakis(triphenylphosphine)palladium(0) dissolved in methylene chloride (catalyst concentration: 1% by mass) B-3: A solution of Tris(dibenzylideneacetone)dipalladium(0) dissolved in methylene chloride (catalyst concentration: 1% by mass) B-4: Solution of tris(triphenylphosphine)rhodium(I) chloride dissolved in methylene chloride (catalyst concentration: 1% by mass) B-5: Tris(dibenzylideneacetone)dipalladium(0) with both ends capped with trimethylsilyl groups, and a kinematic viscosity of 50,000 mmHg at 25°C. 2 Solution of dimethylpolysiloxane at 1 / s (catalyst concentration: 5% by mass) B-6 (for comparison): A solution of platinum-divinyltetramethyldisiloxane complex dissolved in the same dimethylpolysiloxane as A-5 (platinum atom content: 1% by mass).

[0090] (C) Component C-1: Aluminum powder with an average particle size of 8 μm C-2: Zinc oxide powder with an average particle size of 0.4 μm

[0091] Other ingredients D-1: Hydrolyzable organosilane represented by the following formula (2) [ka]

[0092] D-2 (for comparison): 1-ethynyl-1-cyclohexanol represented by the following formula (3) [ka]

[0093] D-3 (for comparison): Methylhydrogendimethylpolysiloxane represented by formula (4) below (Kinematic viscosity at 25°C = 100 mm²) 2 / s) [ka]

[0094] D-4 (for comparison): Methylhydrogendimethylpolysiloxane represented by formula (5) below (Kinematic viscosity at 25°C = 28 mm²) 2 / s) [ka]

[0095] D-5 (for comparison): Methylhydrogendimethylpolysiloxane represented by formula (6) below (Kinematic viscosity at 25°C = 17 mm²) 2 / s) [ka]

[0096] [Examples 1-4] Preparation of curable silicone compositions [1] Components (A) and (B) above were mixed by hand using a spatula in the amounts shown in Table 1 below to prepare a curable silicone composition. The properties of each resulting curable silicone composition were confirmed after heat curing at 150°C for 1.5 hours. The results are shown in Table 1.

[0097] [Table 1]

[0098] The results in Table 1 show that the curable silicone compositions of Examples 1 to 4, which satisfy the requirements of the present invention, can be cured into a gel-like to rubber-like state by heating. Furthermore, it was confirmed that the obtained cured silicone products were [2+2+2] cycloaddition reaction products by nuclear magnetic resonance spectroscopy, infrared spectroscopy, and gel permeation chromatography.

[0099] [Examples 5-8, Comparative Examples 1-3] Preparation of curable silicone compositions [2] Components (A), (B), (C), and (D) above were mixed in the amounts shown in Tables 2 and 3 below using Awatori Rentaro (manufactured by Thinky Co., Ltd.) to prepare curable silicone compositions. The curing time for each obtained curable silicone composition at 25°C was measured. In addition, a predetermined amount of 2-phenylimidazole, represented by formula (7) below, which is a substance that causes curing inhibition in conventionally known addition-curing silicone compositions, was added, and the properties of the composition were confirmed after heating and curing at 150°C for 1.5 hours. The results are shown in Tables 2 and 3. [ka]

[0100] [Table 2]

[0101] [Table 3]

[0102] The results in Tables 2 and 3 show that the silicone compositions of Examples 5 to 8, which satisfy the requirements of the present invention, take a very long time to cure at 25°C, and that even when 10 to 100 ppm of 2-phenylimidazole, a substance that inhibits curing compared to conventionally known addition-curing silicone compositions, can be cured into a rubbery state by heating. Furthermore, it was confirmed that the obtained cured silicone product was a [2+2+2] cycloaddition reaction product by nuclear magnetic resonance spectroscopy, infrared spectroscopy, and gel permeation chromatography.

[0103] On the other hand, Comparative Examples 1 to 3 are conventionally known addition-curing silicone compositions. Although Comparative Example 1 can be cured into a rubbery state by heating even when 100 ppm of 2-phenylimidazole is added, the curing time at 25°C is extremely short at 30 hours. Comparative Examples 2 and 3 have an extended curing time of 7 days at 25°C, but this is still very short compared to Examples 5 to 8. Furthermore, the properties of the compositions after heat curing show that when 1.0 ppm of 2-phenylimidazole is added, it becomes gel-like, and when 10 ppm is added, it does not cure, indicating that the curability has also decreased.

[0104] As shown in Tables 1-3, the curable silicone compositions of the present invention (Examples 1-8) have a sufficiently long curing time at room temperature (25°C), and can be sufficiently cured by heating even when substances that cause curing inhibition in conventional addition-curing silicone compositions are present. This is based on the characteristic of the present invention that the curable silicone composition cures by a [2+2+2] cycloaddition reaction (in other words, the resulting cured silicone product is a [2+2+2] cycloaddition reaction product).

[0105] Therefore, the curable silicone composition of the present invention has the advantage of being able to be stored and transported at room temperature and being less susceptible to substances that cause curing inhibition compared to conventionally known addition-curing silicone compositions. As a result, it is possible to reduce the environmental burden by not requiring special temperature control during storage or transport, and it can be applied to locations where substances that cause curing inhibition compared to conventionally known addition-curing silicone compositions are present.

[0106] Furthermore, the [2+2+2] cycloaddition reaction product of the present invention can be easily and efficiently obtained by a catalytic cycloaddition reaction of an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule. It also has the advantages of not requiring a reaction control agent and being less affected by substances that cause curing inhibition in conventional hydrosilylation reactions, making it an excellent main component of curable silicone compositions.

[0107] This specification includes the following embodiments: [1]: A curable silicone composition, (A) Organopolysiloxane having at least one alkynyl group or nitrile group in one molecule: 100 parts by mass, (B) Transition metal compounds, typical metal compounds, or combinations thereof capable of catalyzing [2+2+2] cycloaddition reactions: effective amount, A curable silicone composition characterized by containing the following: [2]: The kinematic viscosity of component (A) at 25°C is 1 to 20,000,000 mm². 2 The curable silicone composition according to [1], characterized in that it is an organopolysiloxane of the form / s. [3]: The curable silicone composition according to [1] or [2], characterized in that component (A) is an organopolysiloxane having at least one alkynyl group in one molecule. [4]: The curable silicone composition according to any one of [1] to [3], characterized in that the (A) component is an organopolysiloxane having at least one ethynyl group in one molecule. [5]: The curable silicone composition according to any one of [1] to [4], characterized in that the component (B) is a transition metal complex capable of catalyzing a [2+2+2] cycloaddition reaction. [6]: The curable silicone composition according to any one of [1] to [5], further characterized in that (C) contains 0.1 to 5,000 parts by mass of at least one inorganic or organic filler per 100 parts by mass of component (A). [7]: The curable silicone composition according to [6], characterized in that the (C) component is a filler made of one or more materials selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, allotropes of carbon, resins, dyes, and pigments. [8]: A cured silicone product obtained by curing a curable silicone composition described in any one of [1] to [7]. [9]: A method for producing a curable silicone composition, (A) Organopolysiloxane having at least one alkynyl group or nitrile group in one molecule: 100 parts by mass, (B) Transition metal compounds, typical metal compounds, or combinations thereof capable of catalyzing [2+2+2] cycloaddition reactions: effective amount, A method for producing a curable silicone composition, characterized by mixing the following:

[10] A method for manufacturing a silicone cured product, (A) Organopolysiloxane having at least one alkynyl group or nitrile group in one molecule: 100 parts by mass, (B) Transition metal compounds, typical metal compounds, or combinations thereof capable of catalyzing [2+2+2] cycloaddition reactions: effective amount, A method for producing a cured silicone product, characterized by comprising the steps of mixing and curing the resulting mixture.

[11] : A method for curing a curable silicone composition, (A) An organopolysiloxane having at least one alkynyl group or nitrile group in one molecule, (B) A method for curing a curable silicone composition, characterized by curing a mixture containing an effective amount of a transition metal compound, a typical metal compound, or a combination thereof that can catalyze a [2+2+2] cycloaddition reaction.

[12] : A [2+2+2] cycloaddition product of an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule.

[13] : A method for producing a [2+2+2] cycloaddition reaction product, characterized in that (A) an organopolysiloxane having at least one alkynyl group or nitrile group in one molecule is subjected to a [2+2+2] cycloaddition reaction using (B) a transition metal compound, a typical metal compound, or a combination thereof capable of catalyzing a [2+2+2] cycloaddition reaction to obtain the product.

[0108] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention.

Claims

1. A curable silicone composition in which an organopolysiloxane having an alkynyl group is cured by a catalytic [2+2+2] cycloaddition reaction, (A) Organopolysiloxane having two or more alkynyl groups bonded to silicon atoms at the end of the molecular chain or to silicon atoms in the middle of the molecular chain in one molecule: 100 parts by mass, and (B) Transition metal compounds, typical metal compounds, or combinations thereof capable of catalyzing a [2+2+2] cycloaddition reaction: effective amount, A curable silicone composition characterized by containing the following:

2. The kinematic viscosity of component (A) at 25°C is 1 to 20,000,000 mm². ２ The curable silicone composition according to claim 1, characterized in that it is an organopolysiloxane that is / s.

3. The curable silicone composition according to claim 1, characterized in that component (A) is an organopolysiloxane having two or more ethynyl groups in one molecule.

4. The curable silicone composition according to claim 1, characterized in that component (B) is a transition metal complex capable of catalyzing a [2+2+2] cycloaddition reaction.

5. Furthermore, the curable silicone composition according to any one of claims 1 to 4, characterized in that (C) contains 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).

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

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

8. A cured silicone product obtained by curing the curable silicone composition described in claim 5.

9. A method for producing a curable silicone composition in which an organopolysiloxane having an alkynyl group is cured by a catalytic [2+2+2] cycloaddition reaction, (A) Organopolysiloxane having two or more alkynyl groups bonded to silicon atoms at the end of the molecular chain or to silicon atoms in the middle of the molecular chain in one molecule: 100 parts by mass, and (B) Transition metal compounds, typical metal compounds, or combinations thereof capable of catalyzing a [2+2+2] cycloaddition reaction: effective amount, A method for producing a curable silicone composition, characterized by mixing the following:

10. A method for producing a cured silicone product in which an organopolysiloxane having an alkynyl group undergoes a catalytic [2+2+2] cycloaddition reaction, (A) Organopolysiloxane having two or more alkynyl groups bonded to silicon atoms at the end of the molecular chain or to silicon atoms in the middle of the molecular chain in one molecule: 100 parts by mass, and (B) Transition metal compounds, typical metal compounds, or combinations thereof capable of catalyzing a [2+2+2] cycloaddition reaction: effective amount, A method for producing a cured silicone product, characterized by comprising the steps of mixing and curing the resulting mixture.

11. A method for curing a curable silicone composition in which an organopolysiloxane having an alkynyl group is cured by a catalytic [2+2+2] cycloaddition reaction, (A) An organopolysiloxane having two or more alkynyl groups bonded to silicon atoms at the ends of molecular chains or to silicon atoms in the middle of molecular chains in one molecule, (B) A method for curing a curable silicone composition, characterized by curing a mixture containing an effective amount of a transition metal compound, a typical metal compound, or a combination thereof that can catalyze a [2+2+2] cycloaddition reaction.

12. A [2+2+2] cycloaddition product of an organopolysiloxane having two or more alkynyl groups bonded to silicon atoms at the end of the molecular chain or to silicon atoms in the middle of the molecular chain within a single molecule.

13. A method for producing a [2+2+2] cycloaddition reaction product, characterized in that (A) an organopolysiloxane having two or more alkynyl groups bonded to silicon atoms at the end of the molecular chain or to silicon atoms in the middle of the molecular chain in one molecule is subjected to a [2+2+2] cycloaddition reaction using (B) a transition metal compound, a typical metal compound, or a combination thereof capable of catalyzing a [2+2+2] cycloaddition reaction to obtain the product.

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