Polyorganosiloxane

Abstract

This polyorganosiloxane has a structure represented by formula (1). (In formula (1), R's are each independently a group represented by a bond X-Y or a C1-4 monovalent hydrocarbon group; at least one R is a group represented by the bond X-Y; X is a divalent organic group that contains at least one B-O bond; Y has 3 to 6 aromatic six-membered rings that are conjugated; and n is an integer of 1 or greater.)

Description

Polyorganosiloxane

[0001] This invention relates to polyorganosiloxanes.

[0002] In recent years, due to the increasing heat generation associated with the high integration of circuits in electronic devices, thermal management has become crucial, leading to a growing demand for heat dissipation materials. For example, heat dissipation materials using fillers such as graphite are known for their high heat dissipation properties. Generally, fillers have poor dispersibility in solvents, and graphite, in particular, which is a compound with a π-conjugated system, has poor dispersibility, making improvement in terms of heat dissipation necessary.

[0003] It is widely known that dispersants are used to improve the dispersibility of fillers. For example, Patent Document 1 discloses an organopolysiloxane having multiple aromatic rings at one end of a specific structural formula as a surface treatment agent for various functional fillers, and further states that n, the polymerization number of O-Si bonds, is an integer between 0 and 200. In addition, polyorganosiloxanes with polycyclic aromatic groups introduced (hereinafter also referred to as "polycyclic aromatic-introduced polyorganosiloxanes") have also been considered as dispersants to appropriately surface-treat π-electron fillers such as nanocarbon and graphite (π-electron fillers) (see, for example, Patent Documents 2 and 3).

[0004] Japanese Patent Publication No. 2016-534161, Japanese Patent Publication No. 2018-197300, International Publication No. 2024 / 111519

[0005] Conventional polycyclic aromatic polyorganosiloxanes have a problem in which the silicon atoms constituting the silicone structure and the aromatic ring structure are linked by chemical bonds that are easily decomposed under acidic or basic conditions. After the dispersant is prepared, for example, when the dispersant is incorporated into a resin composition containing a filler, the dispersant is decomposed by acidic or basic substances derived from the filler, and the dispersibility is not maintained.

[0006] Patent documents 1 and 2 provide specific examples of bonding sites that connect silicon atoms constituting a silicone structure with an aromatic ring structure, but they do not describe or suggest how to impart acid resistance and base resistance to these bonding sites.

[0007] Therefore, the object of the present invention is to provide a polyorganosiloxane that has excellent adsorption properties to π-electron fillers and excellent acid and base resistance.

[0008] The inventors believed that the above problems could be solved by introducing polycyclic aromatics into silicones that do not have chemical bonds that are weak against acids and bases. After diligent research, they found that the above problems could be solved by linking a silicon atom and a group having three to six conjugated aromatic six-membered rings in a polyorganosiloxane with a divalent organic group containing at least one B-O bond. That is, the present invention provides the following [1] to [9].

[0009] [1] A polyorganosiloxane having a structure represented by the following formula (1). (In formula (1), each R is independently a group represented by bond X-Y, or a monovalent hydrocarbon group having 1 to 4 carbon atoms, at least one of the Rs is the group represented by bond X-Y, X is a divalent organic group containing at least one B-O bond, Y has three to six conjugated aromatic six-membered rings, and n is an integer of 1 or more.) [2] The polyorganosiloxane according to [1] having a structure represented by the following formula (2). (In formula (2), R is a monovalent hydrocarbon group having 1 to 4 carbon atoms, and X, Y, and n are the same as those in formula (1).) [3] The polyorganosiloxane according to [1] or [2], wherein X comprises a boronic acid ester structure. [4] The polyorganosiloxane according to any one of [1] to [3], wherein Y comprises at least one fused ring structure. [5] The polyorganosiloxane according to any one of [1] to [4], wherein Y comprises two or fewer hydrogen atoms directly bonded to the aromatic six-membered ring directly bonded to X. [6] The polyorganosiloxane according to any one of [1] to [5], wherein X comprises a structure represented by the following formula (5). (In equation (5), * is a coupling, R １ ~R ３(wherein is a hydrogen atom or a monovalent hydrocarbon group having 1 to 4 carbon atoms.) A resin composition comprising a polyorganosiloxane according to any one of [1] to [6], a filler, and a resin. [8] The resin composition according to [7], wherein the filler comprises a filler having π electrons. [9] The resin composition according to [7] or [8], wherein the resin comprises a silicone resin.

[0010] According to the present invention, it is possible to provide a polyorganosiloxane that has excellent adsorption properties to π-electron fillers and excellent acid and base resistance.

[0011] [Polyorganosiloxane] <Polyorganosiloxane represented by formula (1)> The polyorganosiloxane of the present invention has a structure represented by the following formula (1). (In formula (1), each R is independently a group represented by a bond X-Y, or a monovalent hydrocarbon group having 1 to 4 carbon atoms, at least one of the Rs is the group represented by the bond X-Y, X is a divalent organic group containing at least one B-O bond, Y has three to six conjugated aromatic six-membered rings, and n is an integer of 1 or more.)

[0012] In the polyorganosiloxane of the present invention, X is a divalent organic group containing at least one B-O bond. The inclusion of a B-O bond can impart excellent acid and base resistance to the polyorganosiloxane. The reason for this is not entirely clear, but it is presumed that the B-O bond is highly stable and resistant to hydrolysis by acidic and basic components. X may have one B-O bond or two or more, but it is preferable to have two or more, more preferably in the range of two to five, and even more preferably two. As will be described later, it is preferable for X to have an O-B-O bond, in which case the B-O bond is counted as two.

[0013] X is a divalent organic group bonded to the silicon atom of formula (1) and Y. Preferably, X is a divalent organic group having 11 or fewer carbon atoms, and more preferably a divalent organic group having 10 or fewer carbon atoms. Polyorganosiloxanes in which the number of carbon atoms of X is below a certain limit are preferable because, when blended into a resin composition, for example, described later, they blend well with matrix resins such as silicone resins, and the dispersibility of the filler is easily improved. Furthermore, there is no particular lower limit to the number of carbon atoms of X, but preferably Y is a divalent organic group having 4 or more carbon atoms, and more preferably a divalent organic group having 5 or more carbon atoms.

[0014] X preferably contains a boronic acid ester structure. The inclusion of a boronic acid ester structure further improves the acid and base resistance of the polyorganosiloxane. The boronic acid ester preferably has an O-B-O bond, and more preferably the O-B-O bond constitutes a cyclic ester. The cyclic ester composed of the boronic acid ester is preferably a 5- to 8-membered ring, more preferably a 5-membered or 6-membered ring, and even more preferably a 6-membered ring. However, the B-O bond does not need to constitute a cyclic ester; R ＊ -B-O is also acceptable. ＊ -B-O, R ＊ This is a hydrocarbon group, preferably an alkyl group, and it is preferable that the O (oxygen atom) is bonded to another atom.

[0015] Among the atoms constituting X, it is preferable that any one of the α-position atom, β-position atom, and γ-position atom is a boron atom or an oxygen atom, and it is more preferable that the α-position atom is a boron atom and the β-position atom is an oxygen atom. Thereby, the acid resistance and base resistance of the polyorganosiloxane are likely to be improved. Here, the α-position atom is an atom bonded to the conjugated ring possessed by Y (that is, one of the aromatic 6-membered rings among the three or more aromatic 6-membered rings possessed by Y) among the atoms constituting X. The β-position atom is an atom bonded to the α-position atom among the atoms constituting X. The γ-position atom is an atom bonded to the β-position atom and other than the α-position atom. In addition, X may also have at least either a boron atom or an oxygen atom in the part other than the α-position atom, β-position atom, and γ-position atom.

[0016] X may have heteroatoms other than the B—O bond. The heteroatoms other than the B—O bond are not particularly limited, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, etc. Among them, an oxygen atom is preferable. Therefore, X may have a structural unit having a heteroatom other than the B—O bond. Examples of the structural unit include ether, ester, amide, urethane, thioether, thioester, etc. Among them, ether or ester is preferable, and from the viewpoints of acid resistance and base resistance, ether is more preferable.

[0017] From the viewpoint of more easily further improving the acid resistance and base resistance, X preferably contains a structure represented by the following formula (5). In formula (5), * is a bond, and R １ ~R ３ is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. R １ ~R ３ may all be the same or at least any one of them may be different, but it is preferable that R ２ and R ３ are the same and only R １ is different, and it is more preferable that R １ is a hydrocarbon group having 1 to 4 carbon atoms and the others are hydrogen atoms. R １ is preferably a hydrocarbon group having 1 to 3 carbon atoms, and more preferably an ethyl group.

[0018] Furthermore, from the viewpoint of improving adsorption to fillers and compatibility with resins, it is more preferable that X has a skeleton represented by either formula (6) or formula (7) below. In formulas (6) and (7), *5 is a bond that attaches to the aromatic six-membered ring of Y, and *6 is a bond that attaches to the silicon atom in formula (1).

[0019] In formula (1), Y has three to six conjugated aromatic six-membered rings. Conjugation refers to a molecular structure in which unsaturated bonds and single bonds alternate, leading to stabilization through p-orbital interactions and electron delocalization (spread throughout the entire conjugated system). If the number of aromatic six-membered rings is seven or more, the fluidity of the polyorganosiloxane deteriorates, resulting in poor filler dispersibility. If the number of aromatic six-membered rings is two or less, the adsorption to the filler decreases, resulting in poor filler dispersibility. From the viewpoint of improving both adsorption to the filler and fluidity in a balanced manner, it is preferable that the number of aromatic six-membered rings be three to five, and more preferably four to five.

[0020] The conjugated aromatic six-membered rings, comprising three to six aromatic six-membered rings, may include a fused ring structure or a non-fused ring structure composed of three to six aromatic six-membered rings. If the conjugated aromatic six-membered rings, comprising three to six aromatic six-membered rings, may consist of one fused ring structure composed of three to six aromatic six-membered rings, a combination of a fused ring structure and a non-fused ring structure, or a combination of two or more fused ring structures. In the case of a combination of a fused ring structure and a non-fused ring structure, or a combination of two or more fused ring structures, it is preferable that the fused ring structure and the non-fused ring structure or fused ring structure are linked via a single bond. The conjugated aromatic six-membered rings, comprising three to six aromatic six-membered rings, preferably include at least one fused ring structure, and more preferably consist of one fused ring structure composed of three to six aromatic six-membered rings. In the polyorganosiloxane of the present invention, if Y includes at least one fused ring structure, the adsorption to fillers tends to be further improved.

[0021] The conjugated aromatic six-membered ring, comprising three to six atoms, may have substituents. Examples of substituents include organic groups having 1 to 10 carbon atoms. More specifically, examples include hydrocarbon groups such as alkyl groups, benzyl groups, and aralkyl groups such as phenethyl groups. Among these, benzyl groups and alkyl groups are preferred. When the substituent of the aromatic six-membered ring is an alkyl group, the alkyl group may be linear, branched, or cyclic. Furthermore, in the conjugated aromatic six-membered ring, it is preferable that all atoms constituting the ring are carbon atoms.

[0022] When a conjugated aromatic six-membered ring of three to six atoms constitutes a single fused ring structure, examples of substituted compounds include anthracene, phenanthrene, triphenylene, pyrene, tetracene, picene, perylene, pentaphene, pentacene, or hexaphene. Among these, anthracene, triphenylene, pyrene, or perylene substituted compounds are preferred, anthracene, pyrene, or perylene substituted compounds are more preferred, anthracene or pyrene substituted compounds are even more preferred, and pyrene substituted compounds are even more preferred. Here, "substituted compound" means that it may have substituents; for example, anthracene substituted compound means that it includes both anthracene and anthracene with substituents. However, the anthracene referred to here is not only a substituent, but also a compound in which one of the hydrogen atoms constituting the conjugated aromatic ring structure of three to six atoms is substituted by a bonding bond. The same applies to other substituted compounds described above or later. Furthermore, when a conjugated aromatic six-membered ring of three to six atoms has substituents, at least one of the hydrogen atoms constituting the conjugated aromatic six-membered ring of three to six atoms is substituted by the substituent. Examples of substituents include organic groups having 1 to 10 carbon atoms, and the details are as described above. The same applies to cases other than those described below, where a aromatic six-membered ring of three to six atoms is composed of a single fused ring structure.

[0023] When the conjugated aromatic six-membered rings, comprising three to six members, have a non-condensed ring structure, for example, a structure in which multiple aromatic six-membered rings are linked by single bonds, specifically, examples include terphenyl substituted compounds such as para-terphenyl substituted compounds and meta-terphenyl substituted compounds, quaterphenyl substituted compounds, quinkiphenyl substituted compounds, sexiphenyl substituted compounds, triphenylbenzene substituted compounds, and tetraphenylbenzene substituted compounds. Furthermore, when the conjugated aromatic six-membered rings, comprising three to six members, have a combination of a condensed ring structure and a condensed ring structure or a non-condensed ring structure, examples include anthracene derivative substituted compounds such as phenylanthracene substituted compounds, diphenylanthracene substituted compounds, and naphthylanthracene substituted compounds, as well as pyrenylbenzene substituted compounds, phenylnaphthalene substituted compounds, and naphthylbenzene substituted compounds. Note that anthracene derivative substituted compounds preferably have bonds on the anthracene skeleton, and pyrenylbenzene substituted compounds preferably have bonds on the benzene skeleton.

[0024] From the viewpoint of improving compatibility with resins when the polyorganosiloxane of the present invention is blended into resin compositions, for example, as described later, it is preferable that the conjugated aromatic six-membered rings, consisting of three to six members, do not have substituents other than the aromatic six-membered rings. Therefore, the conjugated aromatic six-membered rings, consisting of three to six members, are preferably anthracene, triphenylene, pyrene, perylene, pyrenylbenzene, terphenylene, phenylanthracene, diphenylanthracene, or naphthylanthracene, more preferably anthracene, pyrene, or perylene, and even more preferably anthracene or pyrene.

[0025] In the present invention, Y can be any of the above-mentioned structures without particular limitation, but preferred structures of Y are shown below. In equations (8) to (18) above, * represents a combination that combines with X.

[0026] Among the above formulas (8) to (18), it is preferable that it be any of formulas (8), (11), or (13) to (18), and more preferably any of formulas (8), (11), (13), or (16) to (18).

[0027] In the polyorganosiloxane of the present invention, the number of hydrogen atoms directly bonded to the aromatic six-membered ring directly bonded to X in Y may be four or less, but is preferably two or less, more preferably one or less, and even more preferably zero. When the number of hydrogen atoms is below a certain level, the steric hindrance near the B-O bond is strengthened, making it less susceptible to attack by bases under basic conditions and improving base resistance. Therefore, Y preferably includes a structure represented by any of the above formulas (8) to (11), formula (16), or formula (18), more preferably includes a structure represented by any of the above formulas (11), formula (16), or formula (18), and even more preferably includes a structure represented by any of the above formulas (16) or formula (18).

[0028] In formula (1), at least one R is a group represented by X-Y, and the remaining R is a hydrocarbon group having 1 to 4 carbon atoms. In formula (1), of the multiple Rs, the number of groups represented by X-Y is preferably 1 to 5, more preferably 1 or 2, and the remainder is preferably a monovalent hydrocarbon group having 1 to 4 carbon atoms. If there are multiple groups represented by X-Y, these multiple X-Y groups may be the same or different. As monovalent hydrocarbon groups having 1 to 4 carbon atoms, saturated hydrocarbon groups are preferred, such as alkyl groups such as methyl, ethyl, propyl, and butyl groups, and at least one selected from methyl and butyl groups is preferred. If there are multiple monovalent hydrocarbon groups having 1 to 4 carbon atoms, these multiple monovalent hydrocarbon groups having 1 to 4 carbon atoms may be the same or different. Furthermore, of the multiple Rs that are monovalent hydrocarbon groups having 1 to 4 carbon atoms in one molecule, it is preferable that 80 mol% or more of the Rs are methyl groups, and it is more preferable that 90 mol% or more are methyl groups. Furthermore, while all of the multiple R groups, which are monovalent hydrocarbon groups having 1 to 4 carbon atoms, may be methyl groups, the R group bonded to the terminal silicon atom may include a butyl group or other non-methyl group, while the other R groups may be methyl groups.

[0029] In formula (1), n represents the number of repetitions, and n is an integer of 1 or more. Although n is not particularly limited as long as it is an integer of 1 or more, from the viewpoint of improving fluidity, it is preferably 500 or less, more preferably 300 or less, still more preferably 250 or less, and preferably 20 or more, more preferably 100 or more, still more preferably 150 or more.

[0030] <Polyorganosiloxane represented by formula (2)> The polyorganosiloxane according to one embodiment of the present invention has a structure represented by the following formula (2). The polyorganosiloxane has a group represented by X-Y at one end. (In formula (2), R is a monovalent hydrocarbon group having 1 to 4 carbon atoms, and X, Y, and n have the same meanings as those in formula (1).) Examples of the monovalent hydrocarbon group having 1 to 4 carbon atoms include alkyl groups such as methyl group, ethyl group, propyl group, and butyl group. Among them, at least one selected from methyl group and butyl group is preferable. The alkyl group preferably has a straight chain, but may have a branch. A plurality of Rs may be the same or different. In formula (2), X, Y, and n have the same meanings as those in formula (1) and are as described above. The polyorganosiloxane represented by formula (2) has a group represented by X-Y at one end, and is preferable because the adsorptivity to the filler is likely to be stable.

[0031] <Polyorganosiloxane represented by formula (3)> The polyorganosiloxane according to one embodiment of the present invention has a structure represented by the following formula (3). The polyorganosiloxane has groups represented by X-Y at both ends. (In formula (3), each R is independently a monovalent hydrocarbon group having 1 to 4 carbon atoms, and X, Y, and n have the same meanings as those in formula (1).) R in formula (3) has the same meaning as R in formula (2), and X, Y, and n have the same meanings as those in formula (1).

[0032] <Polyorganosiloxane represented by formula (4)> The polyorganosiloxane according to one embodiment of the present invention has a structure represented by the following formula (4). The polyorganosiloxane has a group represented by X-Y in the side chain. (In formula (4), R is a monovalent hydrocarbon group having 1 to 4 carbon atoms, m is an integer of 1 or more and 10 or less, and X, Y and n are as defined in formula (1).) R in formula (4) is synonymous with R in formula (2), and X, Y and n are as defined in formula (1). In formula (4), m is an integer of 1 or more and 10 or less, preferably an integer of 1 or more and 8 or less, more preferably an integer of 1 or more and 6 or less, still more preferably 1 or more and 4 or less, and even more preferably 1 or 2. When m is within such a range, it is preferable because the adsorptivity to the filler is improved and the self-aggregation of polyorganosiloxanes is suppressed. The polyorganosiloxane represented by formula (4) may be a random polymer or a block polymer. More specifically, the unit shown in the parentheses of m and the unit shown in the parentheses of n may be present in a block or randomly in the molecule.)

[0033] As the polyorganosiloxane used in the present invention, among those described above, it preferably has a structure represented by the above formula (2) or (3), and more preferably has a structure represented by the above formula (2).

[0034] The polyorganosiloxane of the present invention preferably has a number average molecular weight of 5000 or more, more preferably 10000 or more, and still more preferably 15000 or more. When the number average molecular weight of the polyorganosiloxane is at least the above lower limit value, the adsorptivity to the filler is more excellent. Also, from the viewpoint of making it difficult for the filler to aggregate, the number average molecular weight of the polyorganosiloxane is preferably 100000 or less, more preferably 50000 or less, and still more preferably 40000 or less. The number average molecular weight is a value determined by gel permeation chromatography (GPC) measurement and converted to polystyrene. The same applies to the number average molecular weight of the silicone resin described later.

[0035] <Method for Producing Polyorganosiloxanes> The method for producing the polyorganosiloxanes of the present invention is not particularly limited, but for example, the polyorganosiloxanes may be produced by the method shown below. First, a polyorganosiloxane having a generally available functional group (hereinafter also referred to as "polyorganosiloxane (X)") is prepared. Then, the polyorganosiloxanes of the present invention can be produced by reacting the polyorganosiloxane (X) with a compound having at least one B-O bond and three to six conjugated aromatic six-membered rings. Specifically, a boric acid esterification reaction between boric acid and an alcohol may be used. In the method using a boric acid esterification reaction, a polyorganosiloxane (X) having a hydroxyl group such as a diol may be reacted with a compound having a boric acid group such as a dihydroxyboryl group or a hydroxyboryl group and three to six conjugated aromatic six-membered rings.

[0036] [Resin Composition] The polyorganosiloxane described above can be incorporated into a resin composition containing, for example, a filler and a resin. By including the polyorganosiloxane in the resin composition, the polyorganosiloxane and the filler are adsorbed together, and the filler is dispersed in the resin by the polyorganosiloxane. Furthermore, since the polyorganosiloxane of the present invention has excellent acid resistance and base resistance, even if acidic or basic components are generated from the filler in the resin composition, the decomposition of the polyorganosiloxane by these components is suppressed.

[0037] The polyorganosiloxane content in the resin composition is, for example, 0.5 parts by mass to 50 parts by mass, preferably 1 part by mass to 40 parts by mass, and more preferably 3 parts by mass to 30 parts by mass, per 100 parts by mass of filler. A polyorganosiloxane content above the lower limit facilitates proper dispersion of the filler, making it easier to impart excellent flexibility to the resin composition. Furthermore, a polyorganosiloxane content below the upper limit makes it easier to achieve effects commensurate with the polyorganosiloxane content.

[0038] <Filler> By including a filler, the resin composition can be given excellent thermal conductivity. The filler may be one that does not have π electrons or one that has π electrons, but it is preferable to include a filler that has π electrons. Furthermore, it is preferable that the filler that has π electrons has a six-membered ring atomic structure as a constituent unit, and that the six-membered ring atomic structure has π electrons. Specific examples of fillers that have π electrons include boron nitride and carbon materials. By using a filler that has π electrons, the filler is more easily adsorbed onto the linker of the polyorganosiloxane. In addition, since the polyorganosiloxane of the present invention has excellent acid resistance and base resistance, it may also contain an acidic filler or a basic filler as a filler. In particular, it is preferable that the resin composition contains either an acidic filler or a basic filler as the filler that has π electrons, and it is more preferable that it contains either an acidic filler or a basic filler as a carbon material.

[0039] Here, an acidic filler is defined as a filler that, when mixed with water and stirred, results in acidic water, while a basic filler is defined as a filler that, when mixed with water and stirred, results in basic water. For example, 10 g of filler is weighed and mixed with 30 g of water, then stirred for 15 minutes at 100°C using a heating device equipped with a Liebig condenser. After stopping the heating and allowing it to stand for 2 hours, the supernatant liquid is measured using a pH meter. A pH of 6 or less indicates acidity, and a pH of 8 or more indicates basicity. For example, a LAQUA twin pH-22 can be used as a pH meter.

[0040] Examples of boron nitride include hexagonal boron nitride, and more specifically, boron nitride nanotubes, boron nitride nanosheets, and hexagonal boron nitride particles. Boron nitride nanotubes are tubular materials formed from hexagonal boron nitride. The ideal structure of a boron nitride nanotube is one in which the planes of the six-membered ring network are parallel to the tube axis, resulting in a single-walled or multi-walled tube. Boron nitride nanotubes that are single-walled are called single-walled tubes, and those that are multi-walled are called multi-walled tubes. Either single-walled tubes or multi-walled tubes may be used as boron nitride nanotubes, or they may be used in combination.

[0041] Boron nitride nanotubes, for example, have an average diameter of 1 nm to 70 nm and an average length of 100 nm to 50 μm. By keeping the average diameter and average length within the above range, it becomes easier to improve the flexibility of the resin composition while increasing its thermal conductivity. The average diameter of the boron nitride nanotubes is preferably 3 nm or more, more preferably 4 nm or more. Furthermore, the average diameter of the boron nitride nanotubes is preferably 10 nm or less, more preferably 8 nm or less. Furthermore, the average length of the boron nitride nanotubes is preferably 500 nm or more, more preferably 1 μm or more, preferably 20 μm or less, more preferably 8 μm or less, and even more preferably 5 μm or less.

[0042] Note that the diameter of a boron nitride nanotube refers to the outer diameter in the case of a single-walled tube, and the outer diameter of the outermost tube in the case of a multi-walled tube. The diameter and length of a boron nitride nanotube can be measured from images obtained by observation with an electron microscope, such as a TEM (transmission electron microscope), and the average diameter and average length can be determined by the arithmetic mean of any 50 nanotubes. The same applies to the diameter and length of carbon nanotubes, which will be discussed later.

[0043] Boron nitride nanosheets are formed from boron nitride and have an ultra-thin two-dimensional sheet structure, for example, having a structure in which a single or multiple layers of hexagonal boron nitride are laminated. Boron nitride nanosheets with an average thickness of 20 nm or less are used. From the viewpoint of improving thermal conductivity while making the resin composition sufficiently flexible, the average thickness of the boron nitride nanosheet is preferably less than 10 nm, more preferably 6 nm or less, and even more preferably 4 nm or less. The lower limit of the average thickness of the boron nitride nanosheet is not particularly limited, but for example it is 1 nm. The size of the boron nitride nanosheet is not particularly limited, but the average longest diameter is, for example, 200 nm or more and 3 μm or less, preferably 500 nm or more and 2 μm or less. The thickness and longest diameter of boron nitride nanosheets can be measured in images obtained by observation with an electron microscope, such as a TEM (transmission electron microscope). The average thickness and average longest diameter of each boron nitride nanosheet can be determined by the arithmetic mean of any 50 images from the electron microscope. The same method can be used to determine the longest diameter and thickness of carbon nanosheets, as described later.

[0044] Hexagonal boron nitride particles are particulate boron nitride particles other than boron nitride nanosheets and boron nitride nanotubes, and their shape is not particularly limited; they may be flaky, spherical, polygonal, or irregularly shaped boron nitride particles. They may also be aggregated particles formed by the aggregation of multiple primary particles. The primary particle diameter of hexagonal boron nitride particles is not particularly limited and may be nano-sized or micro-sized. For example, the average primary particle diameter of hexagonal boron nitride particles may be, for example, 5 nm to 100 μm, preferably 10 nm to 50 μm, and more preferably 0.1 μm to 40 μm. The particle size of aggregated particles is also not particularly limited; the average particle size of aggregated particles may be, for example, 0.1 μm to 250 μm, more preferably 0.5 μm to 200 μm, and even more preferably 1 μm to 150 μm. The primary particle diameter of hexagonal boron nitride particles and the particle diameter of aggregated particles can be determined by measuring the maximum diameter of the particles in images obtained by observation using an electron microscope such as a TEM (transmission electron microscope) or SEM (scanning electron microscope). The average particle size, such as the average primary particle diameter, can be determined by the arithmetic mean of the maximum diameters of any 50 particles. The same applies to other fillers such as graphite particles, which will be discussed later.

[0045] Carbon materials are not particularly limited, but examples include carbon fibers, carbon nanotubes, carbon nanosheets, graphite, graphene, and carbon black.

[0046] Graphitized carbon fibers are preferred as the carbon fibers. Graphitized carbon fibers have graphite crystal planes (i.e., planes of the six-membered ring network) aligned along the fiber axis, and possess high thermal conductivity in that fiber axis direction. Graphitized carbon fibers with a high degree of graphitization are preferred. The fiber diameter of the graphitized carbon fibers is not particularly limited, but for example, the average diameter is 1 μm to 30 μm, preferably 5 μm to 20 μm. A fiber diameter within this range facilitates industrial production and makes it easier to increase the thermal conductivity of the resin composition. As described above, the average fiber length of the carbon fibers is preferably 10 μm to 600 μm, more preferably 15 μm to 500 μm, and even more preferably 20 μm to 300 μm. The average diameter and average fiber length of carbon fibers can be measured using images obtained from observations with an electron microscope, such as a TEM (transmission electron microscope) or SEM (scanning electron microscope). The arithmetic mean of the diameters and fiber lengths of any 50 carbon fibers can then be used as the average diameter and average fiber length.

[0047] Carbon nanotubes are materials having a structure in which a graphite sheet with a hexagonal network of carbon atoms is wound into a cylindrical shape. Those wound in a single layer are called single-wall carbon nanotubes, and those wound in multiple layers are called multi-wall carbon nanotubes. In this invention, the type of carbon nanotube is not particularly limited and may be single-wall carbon nanotubes, multi-wall carbon nanotubes, or combinations thereof. The average diameter of the carbon nanotubes is preferably 1 nm to 100 nm, and more preferably 2 nm to 15 nm. The average length of the carbon nanotubes is preferably 0.1 μm to 1000 μm, and more preferably 10 μm to 500 μm.

[0048] Carbon nanosheets have a structure in which hexagonal network-like arrangements of carbon atoms are aligned along the plane direction, and have an ultra-thin two-dimensional sheet structure. For example, they have a structure in which layers of hexagonal network-like arrangements of carbon atoms are stacked in single or multiple layers. For example, the average thickness of a carbon nanosheet is 20 nm or less, preferably 10 nm or less. The lower limit of the average thickness of a carbon nanosheet is not particularly limited, but for example it is 0.7 nm. The size of a carbon nanosheet is not particularly limited, but the average longest diameter is for example 0.2 μm to 3 μm, preferably 0.5 μm to 2.5 μm.

[0049] Graphite can be defined as graphite particles. Graphite particles are particles other than the carbon fibers, carbon nanotubes, and carbon nanosheets mentioned above, and their shape is not particularly limited; they may be flaky, spherical, polygonal, or irregularly shaped. They may also be aggregated particles formed by the aggregation of multiple primary particles. For example, the average primary particle diameter of the graphite particles may be, for example, 5 nm to 100 μm, preferably 10 nm to 50 μm, and more preferably 0.1 μm to 40 μm. The particle size of the aggregated particles is also not particularly limited; the average particle size of the aggregated particles may be, for example, 0.1 μm to 250 μm, more preferably 0.5 μm to 200 μm, and even more preferably 1 μm to 150 μm.

[0050] Graphene has a hexagonal mesh-like planar layer and can be obtained, for example, by exfoliating the interlayers of graphite, which has a layered structure in which hexagonal mesh-like planar layers are stacked by van der Waals forces. The average thickness of graphene is, for example, 3 nm to 100 nm, preferably 7 nm to 50 nm. The average thickness can be measured, for example, in an image obtained by observation with a TEM (transmission electron microscope), and can be determined by the arithmetic mean of any 50 points in the electron microscope image.

[0051] Examples of carbon black include channel black, oil furnace black, gas furnace black, thermal black, acetylene black, bone black, graphitized carbon, and Ketjen black. The average primary particle size of the carbon black is not particularly limited, but is often 0.001 to 1 μm, preferably 0.005 to 0.5 μm, and more preferably 0.01 to 0.3 μm.

[0052] In the present invention, when a filler having π electrons is used as the filler, it is preferable to include at least one selected from the group consisting of boron nitride, carbon nanotubes, carbon fibers, graphite, graphene, and carbon black, and it is more preferable to include carbon black. Among the fillers having π electrons, using these fillers makes it easier to improve the thermal conductivity of the resin composition. Furthermore, since these fillers have excellent adsorption properties with polyorganosiloxanes, it is easier to incorporate the fillers into the resin composition in a properly dispersed state.

[0053] Fillers that do not have π electrons are not particularly limited and include, for example, oxides, nitrides, carbides, and metal hydroxides. Examples of oxides include iron oxide, zinc oxide, aluminum oxide such as alumina, metal oxides such as magnesium oxide, titanium oxide, cerium oxide, and zirconium oxide, and oxides other than metal oxides such as silicon oxide (silica). Examples of nitrides include metal nitrides such as aluminum nitride, gallium nitride, chromium nitride, tungsten nitride, magnesium nitride, molybdenum nitride, and lithium nitride, and nitrides other than metal nitrides such as silicon nitride. Examples of carbides include metal carbides such as aluminum carbide, titanium carbide, and tungsten carbide, and carbides other than metal carbides such as silicon carbide and boron carbide. Examples of metal hydroxides include aluminum hydroxide, calcium hydroxide, and magnesium hydroxide.

[0054] The filler content in the resin composition is preferably 10% by mass or more and 95% by mass or less, based on the total amount of the resin composition. By keeping the filler content within the above range, the thermal conductivity can be improved while maintaining the flexibility of the resin composition. More preferably, the filler content in the resin composition is 20% by mass or more and 90% by mass or less, and even more preferably 30% by mass or more and 85% by mass or less.

[0055] <Resin> The resin is not particularly limited, but it is preferable to include a silicone resin. It is preferable to use a silicone resin different from the polyorganosiloxane described above. The silicone resin may serve as the matrix resin in the resin composition, and the filler may be dispersed in the silicone resin and held by the silicone resin.

[0056] The silicone resin is a compound that does not have the structure of formula (1) described above, and is typically a compound that does not have three to six conjugated aromatic six-membered rings. Here, the three to six conjugated aromatic six-membered rings are synonymous with "Y" as explained in formula (1). Examples of silicone resins include curable silicone resins. The curable silicone resin may be either a condensation-curing silicone resin or an addition-curing silicone resin, but an addition-curing silicone resin is preferred.

[0057] The silicone resin may have a branched or linear structure, and specifically, organopolysiloxanes having addition reaction groups are mentioned. Addition reaction groups refer to functional groups that react by addition reactions, and typical examples include alkenyl groups, methacryloyl groups, acryloyl groups, and hydrosilyl groups. Organopolysiloxanes having addition reaction groups are preferably used as addition-curing type silicone resins. Preferably, organopolysiloxanes having alkenyl groups and organopolysiloxanes having hydrosilyl groups are mentioned.

[0058] Organopolysiloxanes having alkenyl groups are addition-curing silicone resins that harden when used in combination with organopolysiloxanes having hydrosilyl groups. Organopolysiloxanes having alkenyl groups may have one or more alkenyl groups in their molecule, preferably two or more. The alkenyl groups may be contained at the ends or in the middle of the polysiloxane molecular chain in the organopolysiloxane, or both ends and in the middle, but it is preferable that they be contained at least at the ends, and even more preferable that they be contained at both ends of the polysiloxane molecular chain. The alkenyl groups are not particularly limited, but examples include those having 2 to 8 carbon atoms, such as vinyl groups, allyl groups, butenyl groups, pentenyl groups, hexenyl groups, heptenyl groups, and octenyl groups. Among these, vinyl groups are preferred from the viewpoint of ease of synthesis and reactivity. Furthermore, the alkenyl group is preferably an alkenyl group directly bonded to a silicon atom.

[0059] In organopolysiloxanes having alkenyl groups, examples of residual groups bonded to silicon atoms other than the alkenyl groups include alkyl groups having about 1 to 18 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl, and dodecyl groups; aryl groups having about 6 to 12 carbon atoms, such as phenyl groups; and aralkyl groups having about 7 to 18 carbon atoms, such as 2-phenylethyl and 2-phenylpropyl groups. Furthermore, substituted hydrocarbon groups such as chloromethyl and 3,3,3-trifluoropropyl groups are also given as specific examples. Of these, methyl groups are preferred from the viewpoint of ease of synthesis. It is also preferable that 80 mol% or more of the residual groups bonded to silicon atoms are methyl groups, more preferably 90 mol% or more are methyl groups, and even more preferably 100 mol% are methyl groups. Typically, organopolysiloxanes having alkenyl groups do not have hydrogen atoms as residual groups bonded to silicon atoms; that is, silicone resins do not contain hydrosilyl groups. Examples of organopolysiloxanes having alkenyl groups include vinyl-terminated polydimethylsiloxanes, vinyl-terminated polyphenylmethylsiloxanes, vinyl-terminated dimethylsiloxane-diphenylsiloxane copolymers, vinyl-terminated dimethylsiloxane-phenylmethylsiloxane copolymers, vinyl-terminated dimethylsiloxane-diethylsiloxane copolymers, and other vinyl-terminated organopolysiloxanes.

[0060] Organopolysiloxanes having hydrosilyl groups are addition-curing silicone resins that harden when used in combination with the above-mentioned organopolysiloxanes having alkenyl groups. Organopolysiloxanes having hydrosilyl groups may have one or more hydrosilyl groups in their molecules. The hydrosilyl groups may be contained at the ends of the molecular chains of the polysiloxane structure, or in the middle of the molecular chain, or both ends and in the middle, but it is preferable that they be contained at least at the ends, and more preferably at both ends of the molecular chains of the polysiloxane structure. Specific examples of the remaining groups bonded to silicon atoms other than the hydrosilyl groups in organopolysiloxanes having hydrosilyl groups are as described for organopolysiloxanes having alkenyl groups, and their explanation is omitted here. Furthermore, methyl groups are preferred as the remaining groups, and their preferred proportion is as described for organopolysiloxanes having alkenyl groups. Furthermore, organopolysiloxanes containing hydrosilyl groups are typically preferable to be free of alkenyl groups.

[0061] Examples of organopolysiloxanes having hydrosilyl groups include methylhydrosiloxane-dimethylsiloxane copolymer, polymethylhydrosiloxane, polyethylhydrosiloxane, and methylhydrosiloxane-phenylmethylsiloxane copolymer. These may or may not contain hydrosilyl groups at their terminal ends.

[0062] The organopolysiloxane may be an organopolysiloxane that does not have an addition reaction group, for example, silicone oil. Examples of silicone oils include straight silicone oils such as dimethyl silicone oil (polydimethylsiloxane), polyphenylmethylsiloxane, dimethylsiloxane-diphenylsiloxane copolymer, and phenylmethylsiloxane oil such as dimethylsiloxane-phenylmethylsiloxane, as well as non-reactive modified silicone oils in which a non-reactive organic group is introduced into the main chain having a polysiloxane structure, the side chains attached to the main chain, or the ends of the main chain. A non-reactive organic group is an organic group that does not have an addition reaction group. Examples of non-reactive modified silicone oils include polyether-modified silicone oil, aralkyl-modified silicone oil, fluoroalkyl-modified silicone oil, long-chain alkyl-modified silicone oil, higher fatty acid ester-modified silicone oil, higher fatty acid amide-modified silicone oil, and phenyl-modified silicone oil. Among the above, straight silicone oil is preferred as the silicone oil, and among straight silicone oils, dimethyl silicone oil is more preferred.

[0063] Furthermore, the organopolysiloxane may be other than those listed above, including organopolysiloxanes having alkoxy groups or organopolysiloxanes having silanol groups. The silicone resin may be used alone from the above-mentioned types, or two or more types may be used in combination.

[0064] The silicone resin preferably has a number average molecular weight of 5,000 to 50,000. When the number average molecular weight is within this range, the resin composition maintains a consistent shape after coating or application while ensuring good coatability and workability, thus easily forming a heat dissipation material. Furthermore, it becomes easier to appropriately disperse and incorporate fillers in large quantities while maintaining the flexibility of the resin composition, thereby improving thermal conductivity. The number average molecular weight is more preferably 7,000 to 40,000, and even more preferably 10,000 to 30,000.

[0065] The silicone resin should be liquid at room temperature (25°C) and atmospheric pressure (1 atm). Being liquid makes it easier to improve the coating and workability of the resin composition. Furthermore, it allows for the proper dispersion of fillers while maintaining a low viscosity of the resin composition, making it easier to incorporate large quantities.

[0066] The resin composition may be curable or non-curable. If it is curable, it may be a one-component curable or a two-component curable. If it is a one-component curable, the silicone resin may contain a silicone resin as the main component and a silicone resin as the curing agent, and more specifically, it is preferable to contain an organopolysiloxane having an alkenyl group and an organopolysiloxane having a hydrosilyl group.

[0067] Furthermore, in the case of a two-component curing type, the resin composition may consist of either one of the two components. Therefore, the resin composition may contain either a silicone resin as the main component or a silicone resin as the curing agent. More specifically, the resin composition may contain either an organopolysiloxane having an alkenyl group or an organopolysiloxane having a hydrosilyl group. However, even in the case of a two-component curing type, the silicone resin may contain, in addition to the organopolysiloxane having an alkenyl group or the organopolysiloxane having a hydrosilyl group, an organopolysiloxane having a hydrosilyl group or an organopolysiloxane having an alkenyl group, as long as curing does not progress. Also, in the case of a two-component curing type, the resin composition may be a mixture of the first and second components.

[0068] In the case of a two-component type, it is preferable that both the first and second components consist of a resin composition containing a polyorganosiloxane, a filler, and a silicone resin. Furthermore, it is preferable that the first component contains an organopolysiloxane having an alkenyl group, and the second component contains an organopolysiloxane having a hydrosilyl group.

[0069] Furthermore, the curable resin composition may contain the above-mentioned non-reactive organopolysiloxane as the silicone resin. For example, in addition to the above-mentioned organopolysiloxane having an alkenyl group or an organopolysiloxane having a hydrosilyl group, it may also contain an organopolysiloxane that does not have an addition reaction group.

[0070] Furthermore, the resin composition may be a non-curing type resin composition, in which case, for example, silicone oil may be used as the silicone resin. Note that a portion of the silicone resin may be a by-product generated in the process of producing the polyorganosiloxane described above. If the silicone resin contains a by-product generated in the process of producing the polyorganosiloxane, it may further contain components other than the by-product.

[0071] The silicone resin content in the resin composition is preferably 3% by mass or more and 80% by mass or less, based on 100% by mass of the resin composition. By keeping the silicone resin content within the above range, the filler can be properly held by the silicone resin. This makes it easier to improve the thermal conductivity while maintaining the flexibility of the resin composition. The silicone resin content in the resin composition is more preferably 5% by mass or more and 70% by mass or less, and even more preferably 10% by mass or more and 60% by mass or less.

[0072] <Additives> The resin composition may contain additives other than the polyorganosiloxane, filler, and resin mentioned above, as needed, within a range that does not hinder the effects of the present invention. For example, if the silicone resin is a curable silicone resin, the resin composition may usually contain a curing catalyst. Examples of curing catalysts include platinum-based catalysts, palladium-based catalysts, and rhodium-based catalysts when the silicone resin is an addition-reaction type silicone resin. The curing catalyst is a catalyst for curing the main agent and the curing agent. The amount of curing catalyst is usually 0.1 to 200 ppm, preferably 0.5 to 100 ppm, relative to the mass of the silicone resin. In addition to the curing catalyst, additives such as alkoxysilane compounds, antioxidants, heat stabilizers, colorants, flame retardants, and antistatic agents may also be included. Other components may be used individually or in combination of two or more.

[0073] The resin composition containing the polyorganosiloxane of the present invention can be suitably used, for example, as a heat dissipation material such as heat dissipation silicone grease or heat dissipation silicone sheet. Furthermore, the resin composition can be used in electronic devices to dissipate heat from various electronic components. Specifically, the resin composition can be placed, for example, between an electronic component such as a semiconductor element and a heat sink, in a cured state as needed, to effectively dissipate heat generated from the electronic component. In addition, as described above, the polyorganosiloxane of the present invention has excellent acid and base resistance, so even if the resin composition contains at least one of an acidic filler and a basic filler, the decomposition of the polyorganosiloxane by acidic and basic components derived from the filler is suppressed, and good dispersibility can be maintained.

[0074] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by these examples.

[0075] [Filler Adsorption] The retention time of the graphite column was measured based on the following measurement conditions. (Measurement conditions) Column: Porous graphite carbon column, packing particle size 3 μm, column length 100 mm Column inner diameter: 1 mm Concentration: 0.1 mass% Flow rate: 0.25 mL / min Column temperature: 40°C Injection volume: 10 μL Detector: PDA (measurement wavelength: 190-600 nm) Mobile phase: THF

[0076] Furthermore, filler adsorption was evaluated based on the measured graphite column retention time. The evaluation criteria are as follows. Note that a longer graphite column retention time indicates higher filler adsorption. (Evaluation Criteria) AA: Graphite column retention time of 10 minutes or more A: Graphite column retention time of 5 minutes or more but less than 10 minutes B: Graphite column retention time of 1 minute or more but less than 5 minutes C: Graphite column retention time of less than 1 minute

[0077] [Acid Resistance] 20 mg of carbon black (1), 20 g of solvent, and 20 mg of polyorganosiloxane prepared in each synthesis example were mixed for 1 hour using the ultrasonic nanodispersant PR-1 manufactured by THINKY Corporation, and the mixture was left to stand for 48 hours. After the above standing period, the volume-based average diameter (μm) of carbon black (1) was measured using the laser diffraction / scattering particle size distribution analyzer Partica LA-960V2 manufactured by HORIBA. Based on the measured volume-based average diameter, the acid resistance was evaluated. The evaluation criteria are as follows: (Evaluation Criteria) AA: Volume-based average diameter is less than 1.2 μm A: Volume-based average diameter is 1.2 μm or more and less than 1.3 μm B: Volume-based average diameter is 1.3 μm or more and less than 2 μm C: Volume-based average diameter is 2 μm or more

[0078] [Inhibition of decomposition by acidic components] The mixture prepared above was centrifuged for 1 hour using a KUBOTA high-speed, high-capacity refrigerated centrifuge 7000 to remove carbon black (1), and then the mixture of polyorganosiloxane and solvent obtained as the supernatant was concentrated using a rotary evaporator to remove the solvent. The purity of the polyorganosiloxane obtained as the residue was １The degradation rate (%) of polyorganosiloxanes in the mixture was calculated by 1H NMR measurement. Based on the calculated degradation rate, the inhibitory effect on degradation of acidic components was evaluated. The evaluation criteria are as follows: (Evaluation Criteria) AA: Degradation rate less than 10% A: Degradation rate 10% or more and less than 30% B: Degradation rate 30% or more and less than 50% C: Degradation rate 50% or more

[0079] [Basic Resistance] The volume-based average diameter (μm) of carbon black (2) was measured using the same method as for acid resistance evaluation, except that the filler was changed from carbon black (1) to carbon black (2). Based on the measured volume-based average diameter, basic resistance was then evaluated. The evaluation criteria are as follows: (Evaluation Criteria) A: Volume-based average diameter is less than 0.5 μm B: Volume-based average diameter is 0.5 μm or more and less than 1 μm C: Volume-based average diameter is 1 μm or more

[0080] [Inhibition of Decomposition against Basic Components] The decomposition rate (%) of polyorganosiloxane in the mixture was calculated using the same method as when evaluating the inhibition of decomposition against acidic components, except that the filler was changed from carbon black (1) to carbon black (2). Then, the inhibition of decomposition against basic components was evaluated based on the calculated decomposition rate. The evaluation criteria are as follows: (Evaluation Criteria) AA: Decomposition rate less than 10% A: Decomposition rate 10% or more and less than 30% B: Decomposition rate 30% or more and less than 50% C: Decomposition rate 50% or more

[0081] [Materials Used] The materials used in the examples and comparative examples are as follows: (Fillers) Carbon black (1): Contains π electrons, manufactured by Mitsubishi Chemical Corporation, "MA-100R" Carbon black (2): Contains π electrons, manufactured by Mitsubishi Chemical Corporation, "#4000B"

[0082] (Polyorganosiloxane) The polyorganosiloxanes used in the examples and comparative examples were those prepared in the following Synthesis Examples 1 to 7 and Comparative Synthesis Examples 1 to 3. <Synthesis Example 1> 75 g of an organosiloxane compound having a 1,3-diol group represented by formula (19) (n=210), 1.3 g of 1-pyreneboronic acid as a monomer, and 75 g of toluene as a solvent were reacted at 100°C for 24 hours in a nitrogen atmosphere. The reaction solution was concentrated using a rotary evaporator and a vacuum dryer, the concentrated residue was washed with 150 g of acetone, and the solution was concentrated again using a rotary evaporator and a vacuum dryer to obtain the polyorganosiloxane of Synthesis Example 1 (polyorganosiloxane (1)). １ The reaction process and the chemical structure of the products were confirmed by 1H NMR measurement. A JEOL "ECX-400" NMR analyzer was used, with deuterated chloroform as the solvent. Measurements were performed at a sample concentration of 1% by mass, at 25°C, a measurement frequency of 400 MHz, and 8 cumulative measurements. The reaction process was similarly investigated for other synthesis examples and comparative synthesis examples. １ This was confirmed by 1H NMR measurement.

[0083] <Synthesis Example 2> The synthesis was carried out in the same manner as in Synthesis Example 1, except that the monomer was changed to 1.7 g of 4-(1-pyrenyl)phenylboronic acid, to obtain the polyorganosiloxane of Synthesis Example 2 (polyorganosiloxane (2)). The reaction equation is as follows.

[0084] <Synthesis Example 3> The synthesis was carried out in the same manner as in Synthesis Example 1, except that the monomer was changed to 1.4 g of 2-p-terphenylboronic acid, to obtain the polyorganosiloxane of Synthesis Example 3 (polyorganosiloxane (3)). The reaction equation is as follows.

[0085] <Synthesis Example 4> The synthesis was carried out in the same manner as in Synthesis Example 1, except that the monomer was changed to 1.4 g of 5'-m-terphenylboronic acid, to obtain the polyorganosiloxane of Synthesis Example 4 (polyorganosiloxane (4)). The reaction equation is as follows.

[0086] <Synthesis Example 5> The synthesis was carried out in the same manner as in Synthesis Example 1, except that the monomer was changed to 1.5 g of 10-phenyl-9-anthraceneboronic acid, to obtain the polyorganosiloxane of Synthesis Example 5 (polyorganosiloxane (5)). The reaction equation is as follows.

[0087] <Synthesis Example 6> The synthesis was carried out in the same manner as in Synthesis Example 1, except that the monomer was changed to 1.9 g of 9,10-diphenylanthracene-2-boronic acid, to obtain the polyorganosiloxane of Synthesis Example 6 (polyorganosiloxane (6)). The reaction equation is as follows.

[0088] <Synthesis Example 7> The synthesis was carried out in the same manner as in Synthesis Example 1, except that the monomer was changed to 1.8 g of 10-(2-naphthyl)anthracene-9-boronic acid, to obtain the polyorganosiloxane of Synthesis Example 7 (polyorganosiloxane (7)). The reaction equation is as follows.

[0089] <Comparative Synthesis Example 1> 75 g of an organosiloxane compound having a 1,3-diol group represented by formula (19) (n=210), 1.2 g of 1-pyrenecarboxaldehyde as a monomer, 75 g of toluene as a solvent, and 0.2 g of a catalyst (Organo Corporation, "Amberlyst 15 dry") were reacted at 100°C for 24 hours in a nitrogen atmosphere. After the reaction, the catalyst was removed by filtration through a 5.0 μm PTFE filter, the filtrate was concentrated using a rotary evaporator and vacuum dryer, the concentrated residue was washed with 150 g of acetone, and the mixture was concentrated again using a rotary evaporator and vacuum dryer to obtain the polyorganosiloxane of Comparative Synthesis Example 1 (polyorganosiloxane (8)). The reaction equation is as follows.

[0090] <Comparative Synthesis Example 2> The synthesis was carried out in the same manner as in Synthesis Example 1, except that the monomer was changed to 0.7 g of phenylboronic acid, to obtain the polyorganosiloxane (polyorganosiloxane (9)) of Comparative Synthesis Example 2. The reaction equation is as follows.

[0091] <Comparative Synthesis Example 3> 10 g of an organosiloxane compound having a hydroxyl group represented by formula (20) (n=140), 0.42 g of 2-methyl-6-nitrobenzoic anhydride, 0.36 g of 4-dimethylaminopyridine, and 200 g of tetrahydrofuran as a solvent were reacted in a nitrogen atmosphere at 25°C for 24 hours. The reaction solution was concentrated using a rotary evaporator and a vacuum dryer, and purified by silica gel column chromatography to obtain the polyorganosiloxane of Comparative Synthesis Example 3 (polyorganosiloxane (10)). The reaction equation is as follows.

[0092] The structural information for each of the polyorganosiloxanes (1) to (10) prepared in the above synthesis examples 1 to 7 and comparative synthesis examples 1 to 3 is shown in Table 1 below.

[0093] (Solvent) Isopropyl alcohol: "Isopropyl alcohol" manufactured by Tokyo Chemical Industry Co., Ltd.

[0094] [Examples 1-7, Comparative Examples 1-3] Various measurements and evaluations were performed using the polyorganosiloxanes (1)-(10) prepared in the above synthesis examples 1-7 and comparative synthesis examples 1-3. The results are shown in Table 2.

[0095]

[0096] As is clear from the above examples, the polyorganosiloxanes satisfying the requirements of the present invention exhibited excellent adsorption to carbon black, which is a π-electron filler, as well as excellent acid and base resistance, indicating that decomposition by acidic and basic components was suppressed. In contrast, the polyorganosiloxanes used in Comparative Examples 1 and 3 did not contain any B-O bonds, and were decomposed by acidic or basic components derived from carbon black, resulting in a larger volume-based average value of carbon black and inferior acid and base resistance. Furthermore, the polyorganosiloxane used in Comparative Example 2 had only one aromatic six-membered ring, and its poor adsorption to the filler prevented it from reducing the volume-based average value of carbon black, resulting in a deterioration of acid resistance as well.

Claims

1. A polyorganosiloxane having a structure represented by the following formula (1). (In formula (1), each R is independently a group represented by a bond X-Y, or a monovalent hydrocarbon group having 1 to 4 carbon atoms; at least one of the Rs is the group represented by the bond X-Y; X is a divalent organic group containing at least one B-O bond; Y has a conjugated aromatic six-membered ring of 3 to 6 members; and n is an integer of 1 or more.) 2. The polyorganosiloxane according to claim 1, having a structure represented by the following formula (2). (In formula (2), R is a monovalent hydrocarbon group having 1 to 4 carbon atoms, and X, Y, and n are the same as those in formula (1).) 3. The polyorganosiloxane according to claim 1 or 2, wherein X comprises a boronic acid ester structure.

4. The polyorganosiloxane according to claim 1 or 2, wherein Y comprises at least one fused ring structure.

5. The polyorganosiloxane according to claim 1 or 2, wherein in Y, the number of hydrogen atoms directly bonded to the aromatic six-membered ring directly bonded to X is two or less.

6. The polyorganosiloxane according to claim 1 or 2, wherein X comprises a structure represented by the following formula (5). (In equation (5), * is a coupling, R １ ~R ３ (This is a hydrogen atom or a monovalent hydrocarbon group having 1 to 4 carbon atoms.) 7. A resin composition comprising the polyorganosiloxane according to claim 1 or 2, a filler, and a resin.

8. The resin composition according to claim 7, wherein the filler comprises a filler having π electrons.

9. The resin composition according to claim 7, wherein the resin comprises a silicone resin.

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