Polyorganosiloxane and resin composition

Abstract

Provided is a polyorganosiloxane having a structure represented by formula (1), wherein the number-average molecular weight of the polyorganosiloxane is 10,000-40,000 and the ratio of the number-average molecular weight to the average number (N(A-B)) of bonds A-B contained in one molecule of the polyorganosiloxane, Mn / N(A-B), is 5,000 or greater. (In formula (1), the R moieties each independently represent a group represented by the A-B or a C1-C4 monovalent hydrocarbon group, at least one of the R moieties represents the group represented by A-B, the A represents a divalent organic group bonded to a silicon atom, the B represents three or more conjugated ring structures that form a shared conjugated system, and n is an integer of 1 or larger.)

Description

Polyorganosiloxane, resin composition

[0001] The present invention relates to a polyorganosiloxane and a resin composition containing the polyorganosiloxane.

[0002] In recent years, with the development of communication technologies such as 5G, heat dissipation measures have become important for electronic devices, and the demand for heat dissipation materials is increasing. Heat dissipation materials are generally formed from resin compositions containing a resin and a filler. To achieve high heat dissipation, it is effective to increase the filler loading or use a filler with higher thermal conductivity. However, in resin compositions containing a resin and a filler, poor compatibility between the resin and the filler can lead to a decrease in the flexibility of the composition and other impairments to the functionality of the material. To improve poor compatibility between the resin and the filler, it is known to add additives that have affinity with both the resin and the filler or to add additives that improve dispersibility in the resin.

[0003] For example, Patent Document 1 discloses a polycyclic aromatic group-terminated polyorganosiloxane represented by a specific structural formula as a treatment agent for improving the dispersibility of nanocarbons in silicone resins, and further states that n, the number of polymerizations of O-Si bonds, is preferably an integer of 2 or more and 100 or less. Patent Document 2 discloses a diol-terminated polyorganosiloxane as a dispersant capable of imparting excellent filler dispersibility in a liquid medium, and further states that the number average molecular weight of the organopolysiloxane is preferably 15,000 or more. Furthermore, Patent Document 3 discloses an organopolysiloxane having multiple aromatic rings at one end represented by a specific structural formula as a surface treatment agent for various functional fillers, and further states that n, the number of polymerizations of O-Si bonds, is an integer of 0 or more and 200 or less.

[0004] JP 2018-197300 A JP 2022-81264 A JP 2016-534161 A

[0005] However, conventional dispersants adsorb to fillers solely through the π-π interactions of the conjugated filler linkers, resulting in insufficient adsorption to fillers and in some cases failing to fully enhance the functionality of heat-dissipating materials. To obtain dispersants with higher adsorption to fillers, it is conceivable to introduce multiple filler linkers into the dispersant. However, the introduction of multiple linkers can cause aggregation of dispersant molecules originating from the linkers, reducing the compatibility of the dispersant with the resin and causing phase separation from the resin, resulting in failure to obtain the desired effect of addition. Patent Documents 1 to 3 do not describe or suggest at all the important issues of the adsorption of dispersants to fillers and filler aggregation caused by dispersants, and do not anticipate achieving both adsorption to fillers and compatibility with resins.

[0006] Therefore, an object of the present invention is to provide a polyorganosiloxane that has high adsorption properties for fillers and excellent compatibility with resins.

[0007] After extensive research, the inventors discovered that increasing the van der Waals force acting between the polymer backbone and the filler surface to a certain level enhances the adsorption of dispersants on the filler surface. While conventional dispersants rely primarily on π-π interactions between the filler linker and the filler, they discovered that dispersants with a polymer backbone and filler linker of a certain molecular weight or greater can adsorb to the filler surface through the dual effects of van der Waals forces and π-π interactions, resulting in a greater dispersant addition effect. Furthermore, they discovered that if the polymer backbone becomes too large and the dispersant has an excessively high molecular weight, entropy makes it difficult for the dispersant molecules to adsorb planarly to the filler surface, making it more likely to form a loop structure, leading to aggregation between fillers via the loop-structured dispersant. Therefore, excessively large dispersant molecular weights reduce the effectiveness of dispersant addition. In light of the above, they discovered that the above-mentioned problems can be solved by using a polyorganosiloxane having a polymer chain and a specific filler linker, with the molecular weight and number of filler linkers adjusted to a predetermined standard, and thus completed the following invention. That is, the present invention provides the following [1] to [9].

[0008] [1] A polyorganosiloxane having a structure represented by the following formula (1), wherein the number average molecular weight of the polyorganosiloxane is 10,000 or more and 40,000 or less, and the average number of bonds A-B contained in one molecule of the polyorganosiloxane (N （Ａ－Ｂ） ) to the number average molecular weight (Mn) ratio (Mn / N （Ａ－Ｂ） ) is 5000 or more. (In formula (1), each R is independently a group represented by A-B or a monovalent hydrocarbon group having 1 to 4 carbon atoms, at least one R among the R is a group represented by A-B, A is a divalent organic group bonded to a silicon atom, B is a conjugated ring structure having three or more conjugated rings forming a common conjugated system, and n is an integer of 1 or more.) [2] The average number of bonds A-B (N （Ａ－Ｂ） The polyorganosiloxane according to [1], wherein the number of groups is 1 to 8. [3] The polyorganosiloxane according to [1] or [2], wherein A has a cyclic ether or ester in its structure. [4] The polyorganosiloxane according to any one of [1] to [3], wherein B is a condensed ring compound. [5] The polyorganosiloxane according to any one of [1] to [4], represented by the following formula (2): (In formula (2), R is a monovalent hydrocarbon group having 1 to 4 carbon atoms, and A, B, and n are the same as those in formula (1).) [6] A polyorganosiloxane according to any one of [1] to [4], represented by the following formula (3): (In formula (3), R is a monovalent hydrocarbon group having 1 to 4 carbon atoms, and A, B, and n are the same as those in formula (1).) [7] A polyorganosiloxane according to any one of [1] to [4], represented by the following formula (4): (In formula (4), R is a monovalent hydrocarbon group having 1 to 4 carbon atoms, m is an integer of 1 to 8, and A, B, and n are the same as those in formula (1).) [8] The polyorganosiloxane according to [7], wherein m is 1 or 2. [9] A resin composition comprising the polyorganosiloxane according to any one of [1] to [8], a silicone resin, and a filler.

[0009] According to the present invention, it is possible to provide a polyorganosiloxane that has high adsorption properties for fillers and excellent compatibility with resins.

[0010] [Polyorganosiloxane] 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-B or a monovalent hydrocarbon group having 1 to 4 carbon atoms; at least one R is a group represented by A-B; A is a divalent organic group bonded to a silicon atom; B is three or more conjugated ring structures that form a common conjugated system; and n is an integer of 1 or greater.)

[0011] The polyorganosiloxane having the structure represented by formula (1) has a number average molecular weight of 10,000 or more and 40,000 or less. If the number average molecular weight is less than 10,000, the polyorganosiloxane and the filler are not sufficiently adsorbed, making it difficult to disperse the filler in the resin using the polyorganosiloxane. Furthermore, if the number average molecular weight exceeds 40,000, a loop structure is formed due to the polymer chain of the polyorganosiloxane, and the filler may aggregate through this loop structure. From these viewpoints, the number average molecular weight of the polyorganosiloxane is preferably 10,200 or more and 35,000 or less, more preferably 10,500 or more and 30,000 or less, even more preferably 15,000 or more and 25,000 or less, and even more preferably more than 16,000 and 25,000 or less. The number average molecular weight is a value obtained by performing gel permeation chromatography (GPC) measurement and converting it into polystyrene. The same applies to the number average molecular weight of the silicone resin described below.

[0012] The polyorganosiloxane of the present invention has an average number of bonds A-B contained in one molecule (N （Ａ－Ｂ） ) to the number average molecular weight ratio (Mn / N （Ａ－Ｂ） ) is 5000 or more. （Ａ－Ｂ）If Mn / N is less than 5000, the proportion of the polymer main chain in the entire polyorganosiloxane molecule will be too low, resulting in insufficient compatibility with the resin, and there is a risk that the filler cannot be sufficiently dispersed in the resin by the polyorganosiloxane. （Ａ－Ｂ） is preferably 5,200 or more, more preferably 8,000 or more, and even more preferably 10,000 or more. （Ａ－Ｂ） is preferably 40,000 or less, more preferably 30,000 or less, and even more preferably 20,000 or less, from the viewpoint of making the number average molecular weight of the polyorganosiloxane within an appropriate numerical range, making it easier to improve adsorption to the filler, and making it easier to suppress aggregation of the filler via the loop structure. In this specification, the bond A-B has the same meaning as the group represented by A-B.

[0013] Also, N （Ａ－Ｂ） can be calculated, for example, by the following procedures (1) to (4). (1) A mass spectrum or an NMR spectrum is measured to identify the structure of the bonds A-B. (2) A UV-Vis absorption spectrum or a quantitative NMR spectrum is measured to calculate the amount of substance (mol / g) of the bonds A-B per unit amount of polyorganosiloxane. (3) The number average molecular weight of the polyorganosiloxane is measured (the method for measuring the number average molecular weight is as described above). From the number average molecular weight, the number of polyorganosiloxane molecules (mol / g) per unit amount of polyorganosiloxane is calculated. (4) The average number of bonds A-B contained in one molecule of polyorganosiloxane (N （Ａ－Ｂ） However, for example, when the structure of the raw material of the polyorganosiloxane is known, some of the steps (1) to (4) above can be omitted.

[0014] <Polyorganosiloxane represented by formula (1)> In formula (1), each R is independently a group represented by A-B or a monovalent hydrocarbon group having 1 to 4 carbon atoms. At least one R among the multiple Rs is a group represented by A-B. A is a divalent organic group and is bonded to the silicon atom of formula (1).

[0015] A is a divalent organic group bonded to the silicon atom of formula (1), preferably a divalent organic group having 11 or less carbon atoms, more preferably a divalent organic group having 10 or less carbon atoms. Thus, polyorganosiloxanes in which A has a certain number of carbon atoms or less are preferred because they tend to improve the dispersibility of the filler. In addition, although the lower limit of the carbon number of A is not particularly limited, it is preferable that A is a divalent organic group having 4 or more carbon atoms.

[0016] A may be a hydrocarbon group, but may also have a heteroatom. When A has a heteroatom, it is preferable that any of the α-, β-, and γ-position atoms among the atoms constituting A is a heteroatom. This makes it easier to improve compatibility with the resin. From the viewpoint of improving compatibility with the resin, it is preferable that the α- or β-position atom is a heteroatom, and it is more preferable that the α-position atom is a heteroatom. Here, the α-position atom is an atom among the atoms constituting A that is bonded to a conjugated ring possessed by B (i.e., one of the three or more conjugated rings possessed by B). The β-position atom is an atom among the atoms constituting A that is bonded to the α-position atom. The γ-position atom is an atom bonded to the β-position atom but is other than the α-position atom. Note that A may also have heteroatoms in portions other than the α-, β-, and γ-position atoms.

[0017] The heteroatom is not particularly limited and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, and a boron atom. Among these, an oxygen atom is preferred from the viewpoint of effectively improving compatibility with resins.

[0018] When A has a heteroatom, A has a structural unit having a heteroatom. Examples of the structural unit include ether, ester, amide, urethane, thioether, and thioester. Among them, from the viewpoint of improving the adsorption to the filler and improving the compatibility with the resin, ether or ester is preferred, ether is more preferred, and cyclic ether is particularly preferred. Note that the cyclic ether is an ether having a structure in which carbon of a cyclic hydrocarbon is substituted with oxygen.

[0019] Furthermore, from the viewpoint of improving the adsorption to the filler and improving the compatibility with the resin, A preferably has a skeleton represented by the following formula (5-1) or formula (5-2). In formula (5-1), *1 and *2 are bonds, and R ４ is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, preferably a hydrogen atom. ４ may be the same or different. ３ is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, preferably a hydrocarbon group having 1 to 4 carbon atoms, more preferably a hydrocarbon group having 1 to 3 carbon atoms, and even more preferably an ethyl group. ５ is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, preferably a hydrogen atom. The oxygen atom in formula (5-1) is the above-mentioned β-position atom or γ-position atom, preferably a β-position atom. In formula (5-2), *3 and *4 are bonds. The oxygen atom having the bond *3 is the above-mentioned α-position atom, β-position atom or γ-position atom. Among the above, it is preferable that A has a skeleton represented by formula (5-1).

[0020] Furthermore, from the viewpoint of improving the adsorption to the filler and compatibility with the resin, A preferably has any of the structures represented by the following formulas (6) to (10). In formulas (6) to (10), *5 represents a bond bonded to the conjugated ring possessed by B, and *6 represents a bond bonded to the silicon atom of formula (1). Furthermore, A may be a group other than those in which any of the α-, β-, and γ-position atoms is a heteroatom. Specifically, A may be a hydrocarbon group such as an alkylene group such as a methylene group or an ethylene group, or an arylene group such as a phenylene group. Furthermore, A may be a group in which an atom other than the α-, β-, and γ-position atoms is a heteroatom, or may be an oxygen-containing hydrocarbon group composed of an alkylene group and an ester group.

[0021] In formula (1), B is a conjugated ring structure of three or more that constitute a common conjugated system. Conjugation refers to the alternating connection of unsaturated bonds and single bonds in a molecular structure, resulting in stabilization due to the interaction of p orbitals and delocalization of electrons (spread throughout the conjugated system). B preferably has three or more aromatic ring structures, and more preferably has three to six conjugated aromatic six-membered rings. When the number of aromatic six-membered rings is three or more, adsorption to the filler is improved, making it easier to disperse the filler in the resin. Furthermore, when the number of aromatic six-membered rings is six or less, the compatibility of the polyorganosiloxane with the resin is likely to be improved. From the viewpoint of improving adsorption to the filler and compatibility with the resin, the number of aromatic six-membered rings is preferably four to five.

[0022] The conjugated ring may be a fused ring compound or a non-fused ring compound, but is preferably a fused ring compound. In this way, when B contains a fused ring compound or when B is a fused ring compound, the adsorption to the filler is improved, and the filler can be easily dispersed in the resin. In addition, the fused ring is preferably an aromatic ring, and the fused ring compound is preferably a fused aromatic ring compound.

[0023] Examples of fused ring compounds include anthracene-substituted compounds, phenanthrene-substituted compounds, triphenylene-substituted compounds, pyrene-substituted compounds, tetracene-substituted compounds, picene-substituted compounds, perylene-substituted compounds, pentaphene-substituted compounds, pentacene-substituted compounds, and hexaphene-substituted compounds. Among these, anthracene-substituted compounds, pyrene-substituted compounds, and perylene-substituted compounds are preferred, and pyrene-substituted compounds and perylene-substituted compounds are more preferred. Here, "substituted compounds" means that they may have a substituent. For example, anthracene-substituted compounds include both anthracene and anthracene having a substituent, and the same applies to other substituents. When a fused ring compound has a substituent, at least one of the hydrogen atoms constituting the fused ring compound is substituted with a substituent. Examples of the substituent include organic groups having 1 to 10 carbon atoms. From the viewpoint of easily improving the compatibility of the polyorganosiloxane of the present invention with resins, it is preferable that the fused ring compound does not have a substituent. Therefore, B is more preferably anthracene, pyrene, or perylene, and particularly preferably pyrene or perylene. In addition, the fused ring compound may be any compound as long as any carbon atom constituting the fused ring is bonded to the above-mentioned A. In addition, the non-fused ring compound is preferably a non-fused aromatic ring compound, for example, a compound having a structure in which multiple aromatic rings are linked by single bonds, such as a substituted terphenyl. In addition, the non-fused ring compound may be any compound as long as any carbon atom constituting the aromatic ring is bonded to the above-mentioned A.

[0024] In the present invention, B can be any of the above-mentioned compounds without any particular limitation, but the preferred structure of B is shown below. In the above formulas (11) to (14), * represents a bond to A.

[0025] Among the above formulas (11) to (14), the compounds of any of formulas (11) to (13), which are fused ring compounds, are preferred, and among these, pyrene of formula (11) or perylene of formula (12) is more preferred, and perylene of formula (12) is even more preferred.

[0026] In formula (1), at least one R is a group represented by A-B, and the remaining R are hydrocarbon groups having 1 to 4 carbon atoms. In formula (1), the number of groups represented by A-B among the multiple R is, for example, 1 to 8, preferably 1 to 5, more preferably 1 to 4, and even more preferably 1 or 2, and the remaining are monovalent hydrocarbon groups having 1 to 4 carbon atoms. When there are multiple groups represented by A-B, the multiple groups represented by A-B may be the same or different. Examples of monovalent hydrocarbon groups having 1 to 4 carbon atoms include methyl, ethyl, propyl, and butyl, with methyl being preferred. When there are multiple monovalent hydrocarbon groups having 1 to 4 carbon atoms, the multiple monovalent hydrocarbon groups having 1 to 4 carbon atoms may be the same or different.

[0027] In formula (1), n ​​means 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 keeping the number average molecular weight of the polyorganosiloxane within a certain range, it is, for example, 530 or less, preferably 500 or less, more preferably 400 or less, and even more preferably 350 or less, and for example, 30 or more, preferably 50 or more, more preferably 100 or more, and even more preferably 150 or more.

[0028] The polyorganosiloxane having the structure represented by formula (1) may have the group represented by A-B at one end, at both ends, on a side chain, at one end and a side chain, or at both ends and a side chain.

[0029] <Polyorganosiloxane Represented by Formula (2)> A 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 A-B at one end. (In formula (2), each R is independently a monovalent hydrocarbon group having 1 to 4 carbon atoms, and A, B, and n are defined as in formula (1).) Examples of the monovalent hydrocarbon group having 1 to 4 carbon atoms include alkyl groups such as methyl, ethyl, propyl, and butyl, and among these, methyl is preferred. The alkyl group is preferably linear, but may be branched. Multiple R groups may be the same or different. In formula (2), A, B, and n are defined as described above in formula (1). The polyorganosiloxane represented by formula (2) has a group represented by A-B at one end, which is preferred because it easily improves adsorption to fillers.

[0030] <Polyorganosiloxane Represented by Formula (3)> A polyorganosiloxane according to one embodiment of the present invention has a structure represented by the following formula (3). The polyorganosiloxane has groups represented by A-B at both ends. (In formula (3), each R is independently a monovalent hydrocarbon group having 1 to 4 carbon atoms, and A, B, and n are defined as those in formula (1).) R in formula (3) is defined as R in formula (2), and A, B, and n are defined as those in formula (1).

[0031] <Polyorganosiloxane Represented by Formula (4)> A 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 A-B on a side chain. (In formula (4), R is a monovalent hydrocarbon group having 1 to 4 carbon atoms or a hydrogen atom, m is an integer of 1 to 10, and A, B, and n are the same as those in formula (1).) R in formula (4) is the same as R in formula (2), and A, B, and n are the same as those in formula (1). In formula (4), m is an integer of 1 to 8, preferably an integer of 1 to 6, more preferably an integer of 1 to 5, and even more preferably 1 or 2. When m is in this range, the adsorption to the filler is improved and self-aggregation of polyorganosiloxanes is suppressed, which is preferable. The polyorganosiloxane represented by formula (4) may be a random polymer or a block polymer. More specifically, the unit shown in parentheses of m and the unit shown in parentheses of n may be present in the molecule in a block form or random form.

[0032] Of the polyorganosiloxanes used in the present invention, those having a structure represented by the above formula (2) or (3) are preferred, and those having a structure represented by the above formula (2) are more preferred.

[0033] <Method for producing polyorganosiloxane> The method for producing the polyorganosiloxane of the present invention is not particularly limited, and can be obtained by reacting a commonly available polyorganosiloxane having a functional group with a compound having three or more conjugated rings that form a common conjugated system and a functional group that can react with the functional group of the polyorganosiloxane. For example, the polyorganosiloxane of the present invention can be produced by using an acetalization reaction between an aldehyde and a diol, or a hydrosilylation reaction between a hydrosilyl group and a carbon-carbon unsaturated bond. For example, the polyorganosiloxane of the present invention can be produced by reacting a polyorganosiloxane having a diol structure with a compound having an aldehyde group and three or more conjugated rings that form a common conjugated system. Alternatively, the polyorganosiloxane of the present invention can be produced by reacting a polyorganosiloxane having hydrosilyl groups at the terminals and / or side chains with a compound having a group having a carbon-carbon unsaturated bond, such as an acrylate group or a methacrylate group, and three or more conjugated rings that form a common conjugated system. The polyorganosiloxane of the present invention may also be obtained by further chain extension of a compound having the structure shown in formulas (1) to (4) with a chain extender. Chain extension makes it easier to increase the number average molecular weight of the polyorganosiloxane of the present invention. The chain extender may be a linear polyorganosiloxane or a cyclic polyorganosiloxane such as octamethylcyclotetrasiloxane or decamethylcyclopentasiloxane.

[0034] [Resin composition] The present invention can also provide a resin composition containing the above-mentioned polyorganosiloxane, a filler, and a silicone resin. By containing the above-mentioned polyorganosiloxane, the resin composition of the present invention can adsorb the polyorganosiloxane and the filler, and the filler is dispersed in the resin by the polyorganosiloxane, thereby reducing the viscosity. Hereinafter, the resin composition will be described in detail.

[0035] The content of polyorganosiloxane in the resin composition is, for example, 0.5 parts by mass or more and 50 parts by mass or less, preferably 1 part by mass or more and 40 parts by mass or less, more preferably 3 parts by mass or more and 30 parts by mass or less, relative to 100 parts by mass of the filler. When the content of polyorganosiloxane is equal to or more than the lower limit, the filler can be properly dispersed, making it easier to impart excellent flexibility to the resin composition. Furthermore, when the content of polyorganosiloxane is equal to or less than the upper limit, it is easier to exhibit an effect commensurate with the content of polyorganosiloxane.

[0036] (Filler) The resin composition of the present invention can be provided with excellent thermal conductivity by including a filler. The filler may be a filler without π electrons or a filler with π electrons, but it is preferable to use a filler with π electrons. In addition, the filler with π electrons has a six-membered ring atomic structure as a constituent unit, and the six-membered ring atomic structure preferably has π electrons. Specific examples of fillers with π electrons include boron nitride and carbon materials. By using a filler with π electrons, the filler is more easily adsorbed to the linker of the polyorganosiloxane.

[0037] 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, forming a single or multiple tube. A boron nitride nanotube that forms a single tube is called a single-wall tube, and a multiple tube is called a multi-wall tube. Either a single-wall tube or a multi-wall tube may be used as the boron nitride nanotube, or a combination of these may be used.

[0038] The boron nitride nanotubes have, for example, an average diameter of 1 nm or more and 70 nm or less and an average length of 100 nm or more and 50 μm or less. By setting the average diameter and average length within the above ranges, the flexibility of the resin composition can be improved while the thermal conductivity of the resin composition can be easily increased. The average diameter of the boron nitride nanotubes is preferably 3 nm or more, more preferably 4 nm or more. The average diameter of the boron nitride nanotubes is preferably 10 nm or less, more preferably 8 nm or less. The average length of the boron nitride nanotubes is preferably 500 nm or more, more preferably 1 μm or more, and preferably 20 μm or less, more preferably 8 μm or less, and even more preferably 5 μm or less.

[0039] 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 boron nitride nanotubes can be measured in images obtained by observation using 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 described later.

[0040] Boron nitride nanosheets are formed from boron nitride and have an ultrathin two-dimensional sheet structure, for example, a structure in which a single layer or multiple layers of hexagonal boron nitride are laminated. As boron nitride nanosheets, for example, those having 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 nanosheets 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 nanosheets is not particularly limited, but is, for example, 1 nm. The size of the boron nitride nanosheets is not particularly limited, but the average longest diameter is, for example, 200 nm to 3 μm, preferably 500 nm to 2 μm. The thickness and maximum diameter of the boron nitride nanosheets can be measured in images obtained by observation using an electron microscope such as a TEM (transmission electron microscope), and the average thickness and maximum diameter of each boron nitride nanosheet can be determined by taking the arithmetic mean of any 50 images in the electron microscope image. The same applies to the maximum diameter and thickness of the carbon nanosheets described below.

[0041] Hexagonal boron nitride particles are particulate boron nitride particles other than boron nitride nanosheets and boron nitride nanotubes. Their shape is not particularly limited and may be any shape, such as scale-like, spherical, polygonal, or irregular. They may also be aggregated particles formed by aggregating a plurality of primary particles. The primary particle size of the hexagonal boron nitride particles is not particularly limited and may be nano-sized or micro-sized. For example, the average primary particle size of the 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 the aggregated particles is also not particularly limited and 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 size and aggregate particle size of hexagonal boron nitride particles can be determined by measuring the maximum particle diameter in an image obtained by observation using an electron microscope such as a TEM (transmission electron microscope) or a SEM (scanning electron microscope). The average particle size, such as the average primary particle size, can be determined by taking the arithmetic mean of the maximum diameters of any 50 particles. The same applies to other fillers, such as graphite particles, which will be described later.

[0042] The carbon material is not particularly limited, but examples thereof include carbon fiber, carbon nanotube, carbon nanosheet, graphite, and graphene.

[0043] As the carbon fiber, graphitized carbon fiber is preferred. Graphitized carbon fiber has graphite crystal planes (i.e., planes of a six-membered ring network) aligned in the fiber axis direction, providing high thermal conductivity in the fiber axis direction. Graphitized carbon fiber preferably has a high degree of graphitization. The fiber diameter of the graphitized carbon fiber is not particularly limited, but for example, the average diameter is 1 μm or more and 30 μm or less, preferably 5 μm or more and 20 μm or less. A fiber diameter within the above 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 fiber is preferably 10 μm or more and 600 μm or less, more preferably 15 μm or more and 500 μm or less, and even more preferably 20 μm or more and 300 μm or less. The average diameter and average fiber length of the carbon fibers may be measured in an image obtained by observation using an electron microscope such as a TEM (transmission electron microscope) or an SEM (scanning electron microscope), and the arithmetic means of the diameters and fiber lengths of any 50 carbon fibers may be used as the average diameter and average fiber length.

[0044] Carbon nanotubes are substances with a cylindrical structure in which graphite sheets with a hexagonal mesh-like carbon atom arrangement are wound. Those wound in one layer are called single-wall carbon nanotubes, and those wound in multiple layers are called multi-wall carbon nanotubes. In the present invention, the type of carbon nanotube is not particularly limited, and single-wall carbon nanotubes, multi-wall carbon nanotubes, or combinations thereof may be used. The average diameter of the carbon nanotubes is preferably 1 nm or more and 100 nm or less, more preferably 2 nm or more and 15 nm or less. The average length of the carbon nanotubes is preferably 0.1 μm or more and 1000 μm or less, more preferably 10 μm or more and 500 μm or less.

[0045] Carbon nanosheets have a structure in which hexagonal mesh-like carbon atom arrangements are arranged along the surface direction, and have an ultrathin two-dimensional sheet structure, for example, a structure in which a single layer or multiple layers of hexagonal mesh-like carbon atom arrangements are laminated. The carbon nanosheets have, for example, an average thickness of 20 nm or less, preferably 10 nm or less. The lower limit of the average thickness of the carbon nanosheets is not particularly limited, but is, for example, 0.7 nm. The size of the carbon nanosheets is not particularly limited, but the average longest diameter is, for example, 0.2 μm to 3 μm, preferably 5 μm to 2.5 μm.

[0046] Examples of graphite include graphite particles. Graphite particles are particles other than the above-mentioned carbon fibers, carbon nanotubes, and carbon nanosheets. The shape of the graphite particles is not particularly limited, and they may be graphite particles of any shape, such as flaky, spherical, polygonal, or irregular. They may also be aggregated particles formed by aggregating 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, and 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.

[0047] Graphene has planar layers in a hexagonal mesh pattern and can be obtained, for example, by exfoliating graphite having a layered structure in which the planar layers in a hexagonal mesh pattern 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 calculated as the arithmetic average of any 50 images in the electron microscope image.

[0048] In the present invention, when a filler having π electrons is used as the filler, it is more preferable to include at least one selected from the group consisting of boron nitride, carbon nanotubes, carbon fibers, graphite, and graphene. Among fillers having π electrons, the use of these fillers makes it easier to improve the thermal conductivity of the resin composition. In addition, these fillers have excellent adsorption properties with polyorganosiloxane, making it easier to incorporate the filler in a state where it is properly dispersed in the resin composition.

[0049] The filler without π electrons is not particularly limited and may include, for example, oxides, nitrides, carbides, and metal hydroxides. Examples of oxides include aluminum oxides such as iron oxide, zinc oxide, and 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, as well as nitrides other than metal nitrides such as silicon nitride. Examples of carbides include metal carbides such as aluminum carbide, titanium carbide, and tungsten carbide, as well as carbides other than metal carbides such as silicon carbide and boron carbide. Examples of metal hydroxides include aluminum hydroxide, calcium hydroxide, and magnesium hydroxide.

[0050] When a filler without π electrons is used, it is preferable to use a metal oxide, and it is more preferable to use aluminum oxide. The average primary particle size of the filler without π electrons is not particularly limited, but is preferably 0.1 μm or more and 100 μm or less, more preferably 0.5 μm or more and 50 μm or less, and even more preferably 0.5 μm or more and 15 μm or less. The above-mentioned fillers may be used alone or in combination of two or more.

[0051] The content of the filler 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 setting the content of the filler within the above range, it is possible to improve the thermal conductivity while maintaining the flexibility of the resin composition. The content of the filler in the resin composition is more preferably 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.

[0052] (Silicone Resin) It is preferable to use a silicone resin other than the polyorganosiloxane described above. The silicone resin may be a matrix resin in the resin composition, and the filler may be dispersed in the silicone resin and held by the silicone resin.

[0053] Silicone resins are typically compounds that do not have three or more conjugated ring structures that constitute a common conjugated system. The three or more conjugated ring structures that constitute a common conjugated system herein have the same meaning as "B" described in formula (1). Examples of silicone resins include curable silicone resins. The curable silicone resins may be either condensation curable silicone resins or addition reaction curable silicone resins, but addition reaction curable silicone resins are preferred.

[0054] The silicone resin may have a branched or linear structure, and specifically includes organopolysiloxanes having addition reactive groups. The addition reactive group refers to a functional group that reacts by addition reaction, and representative examples include alkenyl groups, methacryloyl groups, acryloyl groups, and hydrosilyl groups. The organopolysiloxanes having addition reactive groups are preferably used as addition reaction curable silicone resins. Preferred examples of the organopolysiloxanes having addition reactive groups include organopolysiloxanes having alkenyl groups and organopolysiloxanes having hydrosilyl groups.

[0055] An organopolysiloxane having an alkenyl group is an addition reaction-curable silicone resin that cures when used in combination with an organopolysiloxane having a hydrosilyl group. The organopolysiloxane having an alkenyl group may have one or more alkenyl groups in the molecule, preferably two or more alkenyl groups. The alkenyl group may be contained at either the end or the middle of the molecular chain of the polysiloxane structure in the organopolysiloxane, or may be contained at both the end and the middle. However, it is preferable to contain the alkenyl group at least at the end, and more preferably at both ends of the molecular chain of the polysiloxane structure. The alkenyl group is not particularly limited, but examples include those having 2 to 8 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, and octenyl. Among these, vinyl is preferred from the viewpoints of ease of synthesis and reactivity. The alkenyl group may be an alkenyl group directly bonded to a silicon atom.

[0056] In organopolysiloxanes having alkenyl groups, examples of residual groups bonded to silicon atoms other than alkenyl groups include alkyl groups having about 1 to 18 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl, and dodecyl; aryl groups having about 6 to 12 carbon atoms, such as phenyl; and aralkyl groups having about 7 to 18 carbon atoms, such as 2-phenylethyl and 2-phenylpropyl. Specific examples also include substituted hydrocarbon groups, such as chloromethyl and 3,3,3-trifluoropropyl. Of these, methyl groups are preferred from the standpoint of ease of synthesis. Furthermore, of the residual groups bonded to silicon atoms, preferably 80 mol % or more are methyl groups, more preferably 90 mol % or more are methyl groups, and even more preferably 100 mol % are methyl groups. Alkenyl-containing organopolysiloxanes typically do not have hydrogen atoms as residual groups bonded to silicon atoms; that is, the silicone resin preferably does not contain hydrosilyl groups. Specific examples of organopolysiloxanes having alkenyl groups include organopolysiloxanes having vinyl groups at both ends, such as polydimethylsiloxane having vinyl groups at both ends, polyphenylmethylsiloxane having vinyl groups at both ends, a copolymer of dimethylsiloxane having vinyl groups at both ends and diphenylsiloxane, a copolymer of dimethylsiloxane having vinyl groups at both ends and phenylmethylsiloxane, and a copolymer of dimethylsiloxane having vinyl groups at both ends and diethylsiloxane.

[0057] The organopolysiloxane having a hydrosilyl group is an addition reaction curable silicone resin that cures when used in combination with the above-mentioned organopolysiloxane having an alkenyl group. The organopolysiloxane having a hydrosilyl group may have one or more hydrosilyl groups in the molecule. The hydrosilyl group may be contained either at the end of the molecular chain of the polysiloxane structure or in the middle of the molecular chain, or may be contained at both the end and the middle, but it is preferable to contain it at least at the end, and more preferably at both ends of the molecular chain of the polysiloxane structure. In the organopolysiloxane having a hydrosilyl group, specific examples of residual groups bonded to silicon atoms other than the hydrosilyl group are as described for the organopolysiloxane having an alkenyl group, and therefore their description will be omitted. Furthermore, the residual group is preferably a methyl group, and the preferred proportion is as described for the organopolysiloxane having an alkenyl group. Typically, the organopolysiloxane having a hydrosilyl group does not contain an alkenyl group.

[0058] Examples of organopolysiloxanes having hydrosilyl groups include methylhydrosiloxane-dimethylsiloxane copolymers, polymethylhydrosiloxanes, polyethylhydrosiloxanes, methylhydrosiloxane-phenylmethylsiloxane copolymers, etc. These may or may not contain hydrosilyl groups at the terminals.

[0059] The organopolysiloxane may be an organopolysiloxane that does not have an addition reaction group, such as silicone oil. Examples of silicone oils include straight silicone oils such as dimethylsilicone oil (polydimethylsiloxane), polyphenylmethylsiloxane, dimethylsiloxane-diphenylsiloxane copolymer, and phenylmethylsilicone oils such as dimethylsiloxane-phenylmethylsiloxane, as well as non-reactive modified silicone oils in which a non-reactive organic group has been introduced into a main chain having a polysiloxane structure, a side chain bonded to the main chain, or the end 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, dimethylsilicone oil is more preferred.

[0060] The organopolysiloxane may be other than those mentioned above, and may be an organopolysiloxane having an alkoxy group, an organopolysiloxane having a silanol group, etc. The silicone resin may be used alone from among those mentioned above, or two or more may be used in combination.

[0061] The silicone resin preferably has a number average molecular weight of 5,000 or more and 50,000 or less. When the number average molecular weight is within the above range, the resin composition can be easily formed into a heat-dissipating material, since it can maintain a constant shape after coating or application while improving the coatability and workability of the resin composition. Furthermore, it is easy to properly disperse and incorporate a large amount of filler while ensuring the flexibility of the resin composition, and it also becomes easy to improve thermal conductivity. The number average molecular weight is more preferably 7,000 or more and 40,000 or less, and even more preferably 10,000 or more and 30,000 or less.

[0062] The silicone resin is preferably liquid at room temperature (25°C) and atmospheric pressure (1 atmosphere). Being liquid, the silicone resin facilitates the coating and application properties of the resin composition. Furthermore, the resin composition maintains a low viscosity, allowing the filler to be properly dispersed and incorporated in large quantities.

[0063] The resin composition may be curable or non-curable. In the case of a curable type, it may be a one-component curable type or a two-component curable type. In the case of a one-component curable type, the silicone resin may contain a silicone resin as a main component and a silicone resin as a curing agent. More specifically, it is preferable to contain an organopolysiloxane having an alkenyl group and an organopolysiloxane having a hydrosilyl group.

[0064] In the case of a two-component curing type, the resin composition may comprise any one of the two components. Therefore, the resin composition may contain either a silicone resin as a base component or a silicone resin as a 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 an organopolysiloxane having a hydrosilyl group or an organopolysiloxane having an alkenyl group in addition to an organopolysiloxane having an alkenyl group or an organopolysiloxane having a hydrosilyl group, as long as the curing does not proceed. In the case of a two-component curing type, the resin composition of the present invention may be a mixture of the first and second components.

[0065] In the case of a two-component type, it is preferable that both the first and second components are made of a resin composition containing a polyorganosiloxane, a filler, and a silicone resin. It is also preferable that the first component contains an organopolysiloxane having an alkenyl group, and the second component contains an organopolysiloxane having a hydrosilyl group.

[0066] Furthermore, the curable resin composition may contain the above-described non-reactive organopolysiloxane as the silicone resin, and may contain, for example, an organopolysiloxane having no addition reactive group in addition to the above-described organopolysiloxane having an alkenyl group or organopolysiloxane having a hydrosilyl group.

[0067] The resin composition may also be a non-curable resin composition, and in such a case, for example, silicone oil may be used as the silicone resin. Note that a part of the silicone resin may be a by-product produced in the process of producing the above-mentioned polyorganosiloxane. When the silicone resin contains a by-product produced in the process of producing the polyorganosiloxane, it is preferable that the silicone resin further contains components other than the by-product.

[0068] The content of the silicone resin 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 setting the content of the silicone resin 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 content of the silicone resin 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.

[0069] (Additives) The resin composition of the present invention may contain additives other than the polyorganosiloxane, filler, and silicone resin described above, as needed, as long as they do not impair the effects of the present invention. For example, when the silicone resin is a curable silicone resin, the resin composition may typically contain a curing catalyst. When the silicone resin is an addition reaction silicone resin, examples of the curing catalyst include platinum-based catalysts, palladium-based catalysts, and rhodium-based catalysts. The curing catalyst is used to cure the base resin and curing agent. The amount of the curing catalyst is typically 0.1 to 200 ppm, preferably 0.5 to 100 ppm, based on 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 added. The other components may be used alone or in combination.

[0070] [Physical properties and uses of resin composition] The resin composition of the present invention preferably has a piercing load of 100 mN or less, more preferably 90 mN or less, and even more preferably 80 mN or less. When the piercing load is as low as described above, the adsorption between the polyorganosiloxane and the filler is excellent, and it can be said that the filler can be sufficiently dispersed in the resin by the polyorganosiloxane. The piercing load is not particularly limited in its lower limit, but may be, for example, 1 mN or more, or 2 mN or more. The piercing load is measured by the method described in the examples below.

[0071] As described above, the resin composition of the present invention has excellent thermal conductivity and low viscosity, and therefore can be suitably used as a heat-dissipating material such as a heat-dissipating silicone grease or a heat-dissipating silicone sheet. The resin composition of the present invention can also be used in electronic devices to dissipate heat from various electronic components. Specifically, the resin composition of the present invention, in a cured state as needed, can be placed between an electronic component such as a semiconductor element and a heat sink, for example, to effectively dissipate heat generated from the electronic component.

[0072] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0073] [Number Average Molecular Weight] The number average molecular weight of polyorganosiloxane was measured under the following conditions: A Waters "APC System" was used as the measuring device, an HSPgel HR MB-M 6.0 x 150 mm column was used, and THF was used as the solvent, at a flow rate of 0.5 mL / min and a temperature of 40°C.

[0074] [Piercing Load] The piercing load of the resin composition was measured by the following method. The resin composition was degassed, and 30 g of the degassed thermally conductive composition was introduced into a cylindrical container with a diameter of 25 mm. Next, a piercing rod (rod diameter: 1.8 mm) having a disk-shaped member with a diameter of 2 mm and a thickness of 1 mm at its tip was pressed against the thermally conductive composition introduced into the container from the tip side of the piercing rod at a speed (piercing speed) of 10 mm / min, and the load (mN) was measured when the tip of the piercing rod reached a depth of 2 mm from the liquid surface. Based on the measured load, evaluation was performed according to the following evaluation criteria. The piercing rod was made of stainless steel. Measurements were performed at 25°C, and load measurements were performed using an IMADA "ZTS-5N" piercing rod. Furthermore, the adsorption of the filler was evaluated based on the measured piercing load. The evaluation criteria are as follows. AA: 80mN or less A: More than 80mN and less than 90mN B: More than 90mN and less than 100mN C: More than 100mN

[0075] [Materials Used] The materials used in the Examples and Comparative Examples are as follows: (Filler) Graphite: having π electrons, graphite powder, average particle size 10 μm, flake shape

[0076] (Polyorganosiloxane) The polyorganosiloxanes used in the examples and comparative examples were those synthesized in the following Synthesis Examples 1 to 11 and Comparative Synthesis Examples 1 to 8. Synthesis Example 1 110 g of an organosiloxane compound (n = 236) having a 1,3-diol group represented by formula (15), 1.4 g of 1-pyrenecarboxaldehyde as a monomer, 50 g of toluene as a solvent, and 0.6 g of a catalyst ("Amberlyst 15 dry" manufactured by Organo Corporation) were reacted in a nitrogen atmosphere at 100°C for 24 hours. After the reaction, the catalyst was removed by filtration through a 5.0 μm PTFE filter, and the filtrate was concentrated using a rotary evaporator and a vacuum dryer to obtain the polyorganosiloxane of Synthesis Example 1 (polyorganosiloxane (1)). The reaction formula is as follows: １ The progress of the following reaction was confirmed by H NMR measurement. The NMR measurement was performed using a JEOL "ECX-400" NMR measurement device under the conditions of a sample concentration of 1% by weight using deuterated chloroform as the solvent, 25°C, a measurement frequency of 400 MHz, and 8 accumulations. The progress of the reaction was also confirmed for other synthesis examples and comparative synthesis examples. １ This was confirmed by H NMR measurement.

[0077] Synthesis Example 2 Synthesis was performed in the same manner as in Synthesis Example 1, except that the organosiloxane compound of formula (15) was changed to a compound in which n = 263 and the amount of the compound was changed to 122 g, to obtain polyorganosiloxane (polyorganosiloxane (2)) of Synthesis Example 2. The reaction formula is the same as in Synthesis Example 1, except that the compound of formula (15) was changed to a compound in which n = 263, and therefore is omitted here.

[0078] <Synthesis Example 3> 10 g of the polyorganosiloxane (1) obtained in Synthesis Example 1, 5 g of octamethylcyclotetrasiloxane as an extender, 10 g of toluene as a solvent, and 0.3 g of a catalyst (Organo Corporation, "Amberlyst 15 dry") were reacted in a nitrogen atmosphere at 80 ° C. for 24 hours. After the reaction, the catalyst was removed by filtration through a 5.0 μm PTFE filter, and the filtrate was concentrated using a rotary evaporator and a vacuum dryer. The concentrated residue was then washed with 20 g of acetone to extract and remove unreacted octamethylcyclotetrasiloxane, and then concentrated again using a rotary evaporator and a vacuum dryer to remove traces of acetone. Polyorganosiloxane (polyorganosiloxane (3)) of Synthesis Example 3 was obtained. The reaction formula is shown below. In the polyorganosiloxane (3) obtained as described above, n' was 330.

[0079] Synthesis Example 4 Synthesis was performed in the same manner as in Synthesis Example 1, except that the organosiloxane compound of formula (15) was changed to 67.1 g of a compound in which n = 142, to obtain organopolysiloxane (polyorganosiloxane (4)) of Synthesis Example 4. The reaction scheme is the same as in Synthesis Example 1, except that the compound of formula (15) was changed to a compound in which n = 142, and therefore is omitted here.

[0080] Synthesis Example 5 A polyorganosiloxane (polyorganosiloxane (5)) of Synthesis Example 5 was obtained in the same manner as in Synthesis Example 1, except that the monomer was changed to 1.2 g of 9-anthracenecarboxaldehyde. The reaction formula is as follows:

[0081] Synthesis Example 6 Polyorganosiloxane 6 (polyorganosiloxane (6)) of Synthesis Example 6 was obtained in the same manner as in Synthesis Example 1, except that the monomer was changed to 1.7 g of 3-perylenecarboxaldehyde. The reaction formula is as follows:

[0082] Synthesis Example 7 17 g of an organosiloxane compound (n = 216) having a hydrosilyl group represented by formula (17), 0.6 g of (1-pyrene)methyl methacrylate as a monomer, 50 g of toluene as a solvent, and 0.01 g of Karstedt catalyst (platinum catalyst) as a catalyst were reacted in a nitrogen atmosphere at 100°C for 24 hours. The reaction solution was concentrated using a rotary evaporator and a vacuum dryer to obtain polyorganosiloxane (polyorganosiloxane (7)) of Synthesis Example 7. The reaction formula is as follows:

[0083] Synthesis Example 8 Synthesis was performed in the same manner as in Synthesis Example 7, except that the organosiloxane compound of formula (17) was changed to a compound in which n = 364 and the amount of the compound was changed to 28 g, to obtain polyorganosiloxane (polyorganosiloxane (8)) of Synthesis Example 8. The reaction formula is the same as in Synthesis Example 7, except that the compound of formula (17) was changed to a compound in which n = 364, and therefore is omitted here.

[0084] Synthesis Example 9 Synthesis was performed in the same manner as in Synthesis Example 7, except that the organosiloxane compound of formula (17) was changed to a compound in which n = 135 and the amount of the compound was changed to 11 g, to obtain polyorganosiloxane (polyorganosiloxane (9)) of Synthesis Example 9. The reaction formula is the same as in Synthesis Example 7, except that the compound of formula (17) was changed to a compound in which n = 135, and therefore is omitted here.

[0085] Synthesis Example 10 25 g of an organosiloxane compound having a hydrosilyl group represented by formula (18) (m = 1, n = 335), 0.3 g of 1-pyrenemethyl methacrylate as a monomer, 50 g of toluene as a solvent, and 0.01 g of Karstedt catalyst (platinum catalyst) as a catalyst were reacted in a nitrogen atmosphere at 100°C for 24 hours. The reaction solution was concentrated using a rotary evaporator and a vacuum dryer to obtain polyorganosiloxane of Synthesis Example 10 (polyorganosiloxane (10)). The reaction formula is as follows:

[0086] Synthesis Example 11 A polyorganosiloxane (polyorganosiloxane (11)) of Synthesis Example 11 was obtained by synthesis in the same manner as in Synthesis Example 10, except that the organosiloxane compound of formula (18) was changed to a compound in which m = 4 and the amount of 1-pyrenemethyl methacrylate was changed to 1.2 g. The reaction formula is the same as in Synthesis Example 10, except that the compound of formula (18) was changed to a compound in which m = 4, and therefore is omitted here.

[0087] Synthesis Example 12 A polyorganosiloxane of Synthesis Example 12 (polyorganosiloxane (12)) was obtained in the same manner as in Synthesis Example 1, except that the monomer was changed to 1.5 g of [1,1':4',1"]terphenylcarboxaldehyde. The reaction formula is as follows:

[0088] Comparative Synthesis Example 1 Synthesis was carried out in the same manner as in Synthesis Example 1, except that the organosiloxane compound of formula (15) was changed to a compound where n = 74 and the amount of 1-pyrenecarboxaldehyde was changed to 4.2 g, to obtain polyorganosiloxane (polyorganosiloxane (13)) of Comparative Synthesis Example 1. The reaction formula is the same as in Synthesis Example 1, except that the compound of formula (15) was changed to a compound where n = 74, and therefore is omitted here.

[0089] Comparative Synthesis Example 2 Polyorganosiloxane (polyorganosiloxane (14)) of Comparative Synthesis Example 2 was obtained in the same manner as in Synthesis Example 3, except that the amount of octamethylcyclotetrasiloxane was changed to 20 g. The reaction formula is the same as in Synthesis Example 3 except that n' = 667, and therefore is omitted here.

[0090] Comparative Synthesis Example 3 Synthesis was carried out in the same manner as in Synthesis Example 7, except that the organosiloxane compound of formula (17) was changed to a compound where n = 73 and the amount of organosiloxane compound was changed to 5 g, to obtain polyorganosiloxane (polyorganosiloxane (15)) of Comparative Synthesis Example 3. The reaction formula is the same as in Synthesis Example 7, except that the compound of formula (17) was changed to a compound where n = 73, and therefore is omitted here.

[0091] Comparative Synthesis Example 4 Synthesis was carried out in the same manner as in Synthesis Example 7, except that the organosiloxane compound of formula (17) was changed to a compound in which n = 836 and the amount of the compound was changed to 63 g, to obtain polyorganosiloxane (polyorganosiloxane (16)) of Comparative Synthesis Example 4. The reaction formula is the same as in Synthesis Example 7, except that the compound of formula (17) was changed to a compound in which n = 836, and therefore is omitted here.

[0092] Comparative Synthesis Example 5 A polyorganosiloxane (polyorganosiloxane (17)) of Comparative Synthesis Example 5 was obtained in the same manner as in Synthesis Example 1, except that the monomer was changed to 0.97 g of 2-naphthaldehyde. The reaction formula is as follows:

[0093] Comparative Synthesis Example 6 Synthesis was carried out in the same manner as in Synthesis Example 10, except that the organosiloxane compound of formula (18) was changed to a compound where m = 8, the amount of 1-pyrenemethyl methacrylate was changed to 2.4 g, and the amount of toluene was changed to 150 g, to obtain polyorganosiloxane (polyorganosiloxane (18)) of Comparative Synthesis Example 6. The reaction formula is the same as in Synthesis Example 10, except that the compound of formula (18) was changed to a compound where m = 8, and so is omitted here.

[0094] Comparative Synthesis Example 7 Polyorganosiloxane (polyorganosiloxane (19)) of Comparative Synthesis Example 7 was obtained in the same manner as in Synthesis Example 1, except that the monomer was changed to 0.97 g of 2-naphthaldehyde and the organosiloxane compound was changed to 65.7 g of a compound in which n = 142. The reaction formula is the same as in Comparative Synthesis Example 5, except that the compound of formula (15) was changed to n = 142, and therefore is omitted here.

[0095] Comparative Synthesis Example 8 Polyorganosiloxane (polyorganosiloxane (20)) of Comparative Synthesis Example 8 was obtained in the same manner as in Synthesis Example 3, except that the organosiloxane compound was changed to 7 g of polyorganosiloxane (19) obtained in Comparative Synthesis Example 7 and the amount of octamethylcyclotetrasiloxane was changed to 20 g. The reaction formula is as follows. In the polyorganosiloxane (3) obtained as described above, n' was 330.

[0096] (Resin) Polydimethylsiloxane with a number average molecular weight of 20,000

[0097] [Examples 1 to 12, Comparative Examples 1 to 8] 100 parts by mass of resin, 75.5 parts by mass of filler, and 11.1 parts by mass of polyorganosiloxane were mixed to obtain a silicone resin composition. The piercing load of the obtained silicone resin composition was measured, and the filler adsorption was evaluated based on the measured value. The evaluation results are shown in Table 1. Table 1 also shows the polyorganosiloxane used in each example and comparative example and its details.

[0098] *In Table 1, the number of linkers is the number of R groups represented by A-B among the R groups in formula (1).

[0099] As is clear from the above examples, when polyorganosiloxanes satisfying the requirements of the present invention were blended into a resin composition, the composition had a low piercing load, high adsorption to fillers, and excellent compatibility with resins. In contrast, the polyorganosiloxanes used in Comparative Examples 1 and 3 had number average molecular weights below the specified value, so they had low adsorption to fillers, and the filler could not be sufficiently dispersed by the polyorganosiloxane, resulting in a high piercing load for the resin composition. The polyorganosiloxanes used in Comparative Examples 2 and 4 had number average molecular weights above the specified value, resulting in a high piercing load for the resin composition. This is thought to be because the filler aggregated through the loop structure, making it impossible to sufficiently disperse the filler using the polyorganosiloxane. In addition, the polyorganosiloxanes used in Comparative Examples 5, 7 and 8 had less than three conjugated rings constituting the common conjugated system of the polyorganosiloxanes, so the adsorption to the filler was low, and the filler could not be sufficiently dispersed by the polyorganosiloxane, resulting in a high piercing load of the resin composition. （Ａ－Ｂ）Because the ratio of the polymer main chain to the entire molecule was too low, the polyorganosiloxane was not sufficiently compatible with the resin. As a result, the filler could not be sufficiently dispersed by the polyorganosiloxane, resulting in a high piercing load of the resin composition.

Claims

1. A polyorganosiloxane having a structure represented by the following formula (1), wherein the number average molecular weight of the polyorganosiloxane is 10,000 or more and 40,000 or less, and the average number of bonds A-B (N （Ａ－Ｂ） ) to the number average molecular weight (Mn) ratio (Mn / N （Ａ－Ｂ） ) is 5000 or more. (In formula (1), each R is independently a group represented by A-B or a monovalent hydrocarbon group having 1 to 4 carbon atoms; at least one R among the R is a group represented by A-B; A is a divalent organic group bonded to a silicon atom; B is three or more conjugated ring structures that form a common conjugated system; and n is an integer of 1 or greater.) 2. The average number of bonds A-B (N （Ａ－Ｂ） 2. The polyorganosiloxane according to claim 1, wherein the number of groups is 1 or more and 8 or less.

3. The polyorganosiloxane according to claim 1 or 2, wherein A has a cyclic ether or ester in its structure.

4. The polyorganosiloxane according to claim 1 or 2, wherein B is a fused ring compound.

5. The polyorganosiloxane according to claim 1 or 2, which is represented by the following formula (2): (In formula (2), R is a monovalent hydrocarbon group having 1 to 4 carbon atoms, and A, B, and n are defined as in formula (1).) 6. The polyorganosiloxane according to claim 1 or 2, which is represented by the following formula (3): (In formula (3), R is a monovalent hydrocarbon group having 1 to 4 carbon atoms, and A, B, and n are defined as in formula (1).) 7. The polyorganosiloxane according to claim 1 or 2, which is represented by the following formula (4): (In formula (4), R is a monovalent hydrocarbon group having 1 to 4 carbon atoms, m is an integer of 1 to 8, and A, B, and n are defined as in formula (1).) 8. The polyorganosiloxane according to claim 7, wherein m is 1 or 2.

9. A resin composition comprising the polyorganosiloxane according to claim 1 or 2, a silicone resin, and a filler.

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