Copolymer

Abstract

A copolymer according to the present invention has a specific silicone macro-monomer unit, a specific aromatic ring-containing unit, and a specific reactive functional group-containing unit, wherein the number average molecular weight (Mn) of the silicone macro-monomer unit is 1,500 or greater.　The present invention can provide a copolymer that has high adsorptivity to a π-conjugated filler and is capable of improving fluidity of the π-conjugated filler in a silicone resin.

Description

Copolymer

[0001] This invention relates to copolymer polymers.

[0002] In recent years, due to the increased 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. Heat dissipation materials are generally formed from resin compositions containing resin and fillers. Conductive materials for forming conductive layers and color materials containing pigments also often utilize resin compositions containing resin and fillers.

[0003] Fillers such as boron nitride, graphite, and carbon black have a six-membered ring structure and are known as fillers with a π-electron conjugated system (hereinafter sometimes referred to as π-conjugated fillers), and are used in various applications as inks and resin composites. However, because π-conjugated fillers have low affinity for resins, it is common to use dispersants to improve affinity. Polymer-based dispersants are particularly often used to improve the dispersibility of fillers.

[0004] Polymeric dispersants generally consist of a site that interacts with fillers (sometimes referred to as a filler linker) and a polymer backbone. Examples of using polycyclic aromatic compounds such as pyrene as filler linkers are known. For example, Patent Document 1 describes that a siloxane-modified polymer having a structural unit containing a siloxane structure and a vinyl monomer unit containing a polycyclic aromatic group can effectively disperse carbon nanocomposites. Patent Document 2 also describes a linear compound having a polycyclic aromatic group at the end of a polyorganosiloxane, which can be used as a treatment agent to improve the dispersibility of nanocarbons in silicone resins.

[0005] Japanese Patent Publication No. 2009-227845 Japanese Patent Publication No. 2018-197300

[0006] However, even when a compound having the above-mentioned polycyclic aromatic compound as a filler linker is used as a dispersant for dispersing a π-conjugated filler such as boron nitride or graphite in a silicone resin, the fluidity of the filler in the resin is not sufficiently improved, so the flexibility of the resin composition is reduced and there is room for improvement. Therefore, an object of the present invention is to provide a copolymer polymer having a high adsorptivity to a π-conjugated filler and capable of improving the fluidity of the π-conjugated filler in a silicone resin.

[0007] The inventors of the present invention considered that the dispersant having the above-mentioned polycyclic aromatic compound disclosed in the past has a low filler fluidity because the filler linker is only a polycyclic aromatic compound and the interaction with the π-conjugated filler is weak because it is only a π-π interaction. On the other hand, in order to enhance the interaction with the π-conjugated filler, it is also conceivable to increase the amount of the polycyclic aromatic compound in the dispersant. In this case, however, it is considered that the dispersant does not function as a dispersant because it self-aggregates intramolecularly or intermolecularly or the molecular weight becomes too large and gels.

[0008] As a result of intensive studies to solve the above problems, the inventors of the present invention have found that the above problems can be solved by a copolymer polymer having a specific silicone macromonomer unit, an aromatic ring-containing unit, and a reactive functional group-containing unit, and the number average molecular weight (Mn) of the silicone macromonomer unit is a certain value or more, and have completed the present invention.

[0009] That is, the present invention relates to the following [1] to [7]. [1] A copolymer polymer having a silicone macromonomer unit represented by the following formula (1), an aromatic ring-containing unit represented by formula (2), and a reactive functional group-containing unit represented by formula (3), and the number average molecular weight (Mn) of the silicone macromonomer unit is 1,500 or more. (In formulas (1) to (3), R １ , R ２ , R ３ are each independently a hydrogen atom or a methyl group, and R ４ and R ５Each is independently a hydrocarbon group having 1 to 6 carbon atoms. A plurality of Rs ４ may be the same or different from each other. n1 is 10 or more, and X １ , X ２ , X ３ are each independently an organic group having 1 to 20 carbon atoms. A is a group containing an aromatic ring, B is a group containing a reactive functional group, k represents the number of silicone macromonomer units in the copolymer polymer, l represents the number of aromatic ring-containing units in the copolymer polymer, m represents the number of reactive functional group-containing units in the copolymer polymer, and k, l, and m are each values exceeding 0. ) [2] The copolymer polymer according to [1] above, wherein the ratio (l / k) of l to k is 0.2 or more and 3 or less. [3] The copolymer polymer according to [1] or [2] above, wherein the reactive functional group possessed by B has hydrogen bonding properties. [4] The copolymer polymer according to any one of [1] to [3] above, wherein the weight ratio of the silicone macromonomer unit represented by the following formula (I) to the reactive functional group-containing unit is 5 or more and 80 or less. (Number average molecular weight of silicone macromonomer unit × k) / (Number average molecular weight of reactive functional group-containing unit × m) Formula (I) [5] The copolymer polymer according to any one of [1] to [4] above, having a number average molecular weight (Mn) of 10,000 or more and 30,000 or less and a molecular weight distribution (Mw / Mn) of 5 or less. [6] A resin composition comprising the copolymer polymer according to any one of [1] to [5] above, a silicone resin, and an inorganic filler. [7] The resin composition according to [6] above, wherein the inorganic filler contains a π-conjugated filler.

[0010] According to the present invention, it is possible to provide a copolymer polymer having high adsorptivity to a π-conjugated filler and capable of improving the fluidity of the π-conjugated filler in a silicone resin.

[0011] [Copolymer Polymer] The copolymer polymer of the present invention has a silicone macromonomer unit represented by the following formula (1), an aromatic ring-containing unit represented by formula (2), and a reactive functional group-containing unit represented by formula (3), and the number average molecular weight (Mn) of the silicone macromonomer unit is 1,500 or more.

[0012] (In formulas (1) to (3), R １ , R ２ , R ３ are each independently a hydrogen atom or a methyl group, R ４ and R ５ are each independently a hydrocarbon group having 1 to 6 carbon atoms, and a plurality of R ４ may be the same or different from each other, n1 is 10 or more, X １ , X ２ , X ３ are each independently an organic group having 1 to 20 carbon atoms, A is a group containing an aromatic ring, B is a group containing a reactive functional group, k represents the number of silicone macromonomer units in the copolymer polymer, l represents the number of aromatic ring-containing units in the copolymer polymer, m represents the number of reactive functional group-containing units in the copolymer polymer, and k, l, m are each values exceeding 0.)

[0013] The copolymer polymer of the present invention, when incorporated into a composition of a silicone resin and a π-conjugated filler, can enhance adsorption to the π-conjugated filler and improve fluidity. The reason for this is not entirely clear, but it is presumed to be as follows: The copolymer polymer of the present invention has silicone macromonomer units with a number average molecular weight of 1,500 or more, thus increasing its compatibility with the silicone resin matrix. Furthermore, the copolymer polymer of the present invention has aromatic ring-containing units and reactive functional group-containing units, and it is thought that both of these units function as filler linkers. In more detail, it is thought that the aromatic ring-containing units and reactive functional group-containing units function as units having sites that can interact with the π-conjugated filler, resulting in strong adsorption to the π-conjugated filler. Examples of "sites that can interact" with the π-conjugated filler include sites that can π-π interact (for example, aromatic ring-containing groups such as pyrene, described later), sites that can Lewis acid-base interact, and sites that can interact by intermolecular forces such as hydrogen bonds. More specifically, "interactable sites" include sites where π-π interactions are possible with the smooth surface (Miller constant 001 plane) of the π-conjugated filler (e.g., boron nitride or boron nitride nanotubes), sites where Lewis acid-base interactions are possible with the smooth surface (Miller constant 001 plane) of the π-conjugated filler, and sites where interactions are possible with the filler end face (Miller constant 100 plane) through intermolecular forces such as hydrogen bonding. In the case of nanocarbon fillers (e.g., carbon nanotubes, carbon black, graphene), examples include sites where π-π interactions are possible with the smooth surface (Miller constant 001 plane) of the π-conjugated filler, and sites where interactions are possible with the filler end face (Miller constant 100 plane) through intermolecular forces such as hydrogen bonding. In this way, it is presumed that the dispersibility of the π-conjugated filler in the silicone resin is improved, and the fluidity in the composition is increased. The copolymer polymer of the present invention will be described in detail below.

[0014] <Silicone Macromonomer Unit> The copolymer polymer of the present invention has a silicone macromonomer unit represented by formula (1).

[0015] In equation (1), R１ R is a hydrogen atom or a methyl group, preferably a methyl group. ４ and R ５ Each of these is an independent hydrocarbon group having 1 to 6 carbon atoms, and multiple R ４ These may be the same or different. ４ The group is preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 to 2 carbon atoms, and even more preferably a methyl group. ５ n1 is preferably an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 3 to 4 carbon atoms, and more preferably a butyl group. n1 is 10 or more. n1 is the siloxane moiety (-Si(R ４ ) ２ This is the number of repeating siloxane moieties (-Si(R)) that each of the multiple molecular chains constituting the copolymer has. ４ ) ２ k is the average number of repeats of -O-). n1 is preferably 30 or more, more preferably 40 or more, and even more preferably 50 or more, from the viewpoint of improving the compatibility between the copolymer polymer and the silicone resin. Also, from the viewpoint of lowering the viscosity of the copolymer polymer, n1 is preferably 200 or less, and even more preferably 100 or less. k is the number of silicone macromonomer units represented by formula (1) in the copolymer polymer, and is a value greater than 0. k is more specifically the average number of silicone macromonomer units that each of the multiple molecular chains constituting the copolymer polymer has. k is preferably 0.5 or more, more preferably 0.8 or more, even more preferably 1 or more, even more preferably 1.5 or more, even more preferably 2 or more, and preferably 10 or less, and even more preferably 5 or less, from the viewpoint of improving the compatibility between the copolymer polymer and the silicone resin. k, and l and m described later, which represent the number of repeats of each unit, are the copolymer polymer １ It can be calculated from the molar ratio of each unit obtained by H-NMR measurement and the number-average molecular weight measured by GPC of the copolymer polymer.

[0016] X １This is an organic group having 1 to 20 carbon atoms. This organic group may contain heteroatoms such as oxygen, nitrogen, and sulfur atoms, and may also contain groups such as ether groups, ester groups, amino groups, and amide groups. Among these, X １ It is preferably an organic group having 1 to 20 carbon atoms that contains an ester group, more preferably an organic group having 1 to 10 carbon atoms that contains an ester group, and even more preferably an organic group having 2 to 6 carbon atoms that contains an ester group. In particular, X １ It is preferable that the structure is represented by the following formula (4). R in equation (4) ６ This is an alkylene group having 1 to 5 carbon atoms, preferably an alkylene group having 2 to 5 carbon atoms, and more preferably an alkylene group having 3 to 4 carbon atoms. *1 is a bond that connects to the main chain of the copolymer polymer, and *2 is a bond that connects to Si in formula (1).

[0017] X １ When the structure is represented by formula (4), the silicone macromonomer unit is a constituent unit derived from a (meth)acrylate monomer having a polysiloxane structure. Note that (meth)acrylate refers to both acrylate and methacrylate.

[0018] The number-average molecular weight (Mn) of the silicone macromonomer units is 1,500 or more. If the number-average molecular weight is less than 1,500, the compatibility between the copolymer polymer and the silicone resin decreases, the dispersibility of the π-conjugated filler in the silicone resin decreases, and the fluidity deteriorates. From the viewpoint of improving fluidity, the number-average molecular weight (Mn) of the silicone macromonomer units is preferably 2,000 or more, more preferably 3,000 or more, and even more preferably 6,000 or more. From the viewpoint of lowering the viscosity of the copolymer polymer, it is preferably 15,000 or less, and even more preferably 10,000 or less. The number-average molecular weight (Mn) of the silicone macromonomer units can be calculated by gel permeation chromatography (GPC) measurement and NMR measurement of the copolymer polymer. That is, the number-average molecular weight (Mn) of the copolymer polymer is determined by GPC measurement. １ H-NMR,２９ Si-NMR measurement allows for the determination of the molar ratio of each unit in the copolymer polymer and the repeating number n1 in the silicone macromonomer unit. From this information, the number-average molecular weight (Mn) of the silicone macromonomer unit can be calculated. Alternatively, since the number-average molecular weight (Mn) of the silicone macromonomer unit corresponds to the number-average molecular weight of the monomers used during polymerization to form the silicone macromonomer unit, the number-average molecular weight of these monomers can also be measured by GPC. In this specification, the number-average molecular weight measured by GPC is a value equivalent to standard polystyrene.

[0019] <Aromatic Ring-Containing Unit> The copolymer polymer of the present invention has an aromatic ring-containing unit represented by formula (2).

[0020] In equation (2), R ２ l is a hydrogen atom or a methyl group, preferably a methyl group. In formula (2), l is a value greater than 0. l is the number of aromatic ring-containing units represented by formula (2) in the copolymer polymer, and more specifically, it is the average value of the number of aromatic ring-containing units that each of the multiple molecular chains constituting the copolymer polymer has. From the viewpoint of enhancing interaction with π-conjugated fillers, l is preferably 0.5 or more, more preferably 0.8 or more, even more preferably 1 or more, even more preferably 1.2 or more, and even more preferably 1.5 or more. Also, from the viewpoint of suppressing self-aggregation of the copolymer polymer, it is preferably 5 or less, more preferably 3 or less, and even more preferably 2 or less.

[0021] In formula (2), A is a group having an aromatic ring. A is not particularly limited, but from the viewpoint of enhancing the π-π interaction with the π-conjugated filler, a structure having a long aromatic ring in a conjugated system is preferred. For example, a fused ring compound in which multiple aromatic rings are fused together, or a structure in which multiple aromatic rings are linked by single, double, or triple bonds is preferred. The aromatic ring may be a heteroaromatic ring containing heteroatoms such as oxygen, nitrogen, or sulfur atoms, and the aromatic ring may have a structure other than a six-membered ring, for example, a five-membered ring. At least one of the hydrogen atoms constituting the aromatic ring may be substituted with a substituent. Examples of substituents include organic groups having 1 to 10 carbon atoms. Among these, a fused ring compound in which multiple aromatic rings (six-membered rings) are fused together is more preferred for A. Examples of the above-mentioned fused ring compounds include naphthalene, anthracene, phenanthrene, triphenylene, pyrene, tetracene, picene, perylene, pentaphene, pentacene, and hexaphene. Note that in the fused ring compound, at least one of the hydrogen atoms constituting the fused ring compound may be substituted with a substituent. Examples of substituents include organic groups having 1 to 10 carbon atoms. Among these, from the viewpoint of improving the dispersibility of π-conjugated fillers, the fused ring compound is preferably a fused ring compound having four or more 6-membered rings fused together. Furthermore, among the fused ring compounds having four or more 6-membered rings fused together, pyrene is particularly preferred. Examples of structures in which the above-mentioned multiple aromatic rings are linked by single, double, or triple bonds include azobenzene and terthiophene. While A is preferably a fused ring compound as described above, it may also be a group having only one aromatic ring.

[0022] X ２ This is an organic group having 1 to 20 carbon atoms. This organic group may contain heteroatoms such as oxygen, nitrogen, and sulfur atoms, and may also contain groups such as ether groups, ester groups, amino groups, and amide groups. Among these, X ２ It is preferably an organic group having 1 to 20 carbon atoms that contains an ester group, more preferably an organic group having 1 to 10 carbon atoms that contains an ester group, and even more preferably an organic group having 2 to 6 carbon atoms that contains an ester group. In particular, X ２It is preferable that the structure is represented by the following formula (5).

[0023] R in equation (5) ７ is an alkylene group having 1 to 5 carbon atoms, preferably an alkylene group having 1 to 3 carbon atoms, and more preferably an alkylene group having 1 carbon atom. *3 is a bond that connects to the main chain of the copolymer polymer, and *4 is a bond that connects to A in formula (2).

[0024] X ２ When the structure is represented by formula (5), the aromatic ring-containing unit is a constituent unit derived from a (meth)acrylate monomer having an aromatic ring. As the (meth)acrylate monomer having an aromatic ring, the above-mentioned condensed ring compound (meth)acrylate monomer is preferred.

[0025] <Reactive Functional Group-Containing Unit> The copolymer polymer of the present invention has a reactive functional group-containing unit represented by formula (3).

[0026] In equation (3), R ３ m is a hydrogen atom or a methyl group, preferably a methyl group. In formula (3), m is a value greater than 0. m is the number of reactive functional group-containing units represented by formula (3) in the copolymer polymer, and more specifically, it is the average value of the number of reactive functional group-containing units that each of the multiple molecular chains constituting the copolymer polymer has. From the viewpoint of enhancing interaction with π-conjugated fillers, m is preferably 0.5 or more, more preferably 0.8 or more, even more preferably 1 or more, even more preferably 1.1 or more, and even more preferably 1.3 or more. Also, from the viewpoint of suppressing phase separation of the resin composition, it is preferably 5 or less, more preferably 4 or less, and even more preferably 2 or less.

[0027] B is a group containing a reactive functional group. The reactive functional group is not particularly limited, but it is preferably one or more selected from the group consisting of vinyl group, acid anhydride group, carboxyl group, amino group, hydroxyl group, isocyanate group, urethane group, oxazoline group, oxetane group, cyanate group, phenol group, hydrazide group, alkoxysilyl group, and phenol group. As a reactive functional group, it is preferable that it has hydrogen bonding properties because it readily interacts with the functional groups on the filler surface. Examples of functional groups with hydrogen bonding properties include acid anhydride group, carboxyl group, amino group, hydroxyl group, phenol group, amide group, and alkoxysilyl group, with the hydroxyl group being preferred.

[0028] If B is a group containing a hydroxyl group, it is preferable that B has a polyoxyalkylene structure from the viewpoint of enhancing interaction with the filler. From this viewpoint, it is preferable that B has the structure shown in the following formula (6).

[0029] In equation (6), R ８ is an alkylene group having 2 to 4 carbon atoms, preferably an ethylene group. Also, n ２ is an oxyalkylene group (R ８ -O) represents the number of repetitions, which is 1 to 50, preferably 2 to 20, and more preferably 4 to 10. In formula (6), *5 is X in formula (3). ３ This is a bonding operation that connects to [another bond].

[0030] X in equation (3) ３ This is an organic group having 1 to 20 carbon atoms, preferably an organic group having 1 to 10 carbon atoms. This organic group may contain heteroatoms such as oxygen, nitrogen, and sulfur atoms, and may also contain groups such as ether groups, ester groups, amino groups, and amide groups. Among these, X ３ It is preferably an organic group containing an ester group, and more preferably a structure represented by the following formula (7).

[0031] In equation (7), R ９R is a single bond or an alkylene group having 1 to 5 carbon atoms, and a single bond is preferred. *6 is a bond that connects to the main chain of the copolymer polymer, and *7 is a bond that connects to B in formula (3). ９ If it is a single bond, then formula (7) becomes an ester group. That is, X ３ It is preferable that it is an ester group.

[0032] X ３ When the structure is represented by formula (7), the reactive functional group-containing unit is a constituent unit derived from a (meth)acrylate monomer having a reactive functional group. As the (meth)acrylate monomer having a reactive functional group, a (meth)acrylate monomer having a hydroxyl group is preferred, and a (meth)acrylate monomer having a polyoxyalkylene structure is more preferred.

[0033] As described above, in the copolymer polymer of the present invention, X １ Equation (4), X ２ Equation (5), X ３ The structure of formula (7) is preferred, in which case the copolymer polymer is a polymer having a (meth)acrylate-derived backbone.

[0034] <Unit Ratio> The ratio of the number of units in formulas (1) to (3) described above is preferably as follows: The ratio of l to k (l / k), which is the number of silicone macromonomer units in the copolymer polymer and the number of aromatic ring-containing units in the copolymer polymer, is preferably 0.2 or more and 3 or less, more preferably 0.4 or more and 2 or less, and even more preferably 0.6 or more and 1 or less. When the ratio (l / k) is above the lower limit, the interaction of the copolymer polymer with the π-conjugated filler can be further enhanced. When the ratio (l / k) is below the upper limit, self-aggregation and phase separation of the copolymer polymer can be more easily suppressed, and the compatibility of the copolymer polymer with the silicone resin is further enhanced. As a result, when the ratio (l / k) is within the above numerical range, the dispersibility of the π-conjugated filler in the silicone resin is further enhanced, and the fluidity can be further improved.

[0035] Furthermore, the weight ratio of the silicone macromonomer unit to the reactive functional group-containing unit, as shown in the following formula (3), is preferably 5 to 80, more preferably 8 to 70, and even more preferably 12 to 60. (Number average molecular weight of the silicone macromonomer unit × k) / (Number average molecular weight of the reactive functional group-containing unit × m) Formula (3)

[0036] If the weight ratio shown in equation (3) is above the lower limit, the compatibility of the copolymer polymer with the silicone resin is further enhanced. If the weight ratio shown in equation (3) is below the upper limit, the viscosity increase of the copolymer polymer is more easily suppressed. As a result, if the weight ratio shown in equation (3) is within the above numerical range, the dispersibility of the π-conjugated filler in the silicone resin is further enhanced, and the fluidity can be further improved.

[0037] The method for measuring the number-average molecular weight of silicone macromonomer units is as described above. The number-average molecular weight of reactive functional group-containing units can be calculated by GPC and NMR measurements of the copolymer polymer, similar to the number-average molecular weight of silicone macromonomer units. Alternatively, since the number-average molecular weight of reactive functional group-containing units corresponds to the number-average molecular weight of the monomers used during polymerization to form the reactive functional group-containing units, the number-average molecular weight of the monomers may be measured by GPC. The number-average molecular weight measured by GPC is a standard polystyrene equivalent value.

[0038] The copolymer polymer of the present invention may contain other units besides the silicone macromonomer unit represented by formula (1), the aromatic ring-containing unit represented by formula (2), and the reactive functional group-containing unit represented by formula (3), to the extent that they do not impede the effects of the present invention. The number of other units is preferably small from the viewpoint of interaction with π-conjugated fillers and compatibility with silicone resins. The number of other units relative to the total number of units in the copolymer polymer is preferably 5% or less, more preferably 3% or less, and even more preferably 0%.

[0039] The copolymer polymer of the present invention can also be represented by the following formula (8).

[0040] In equation (8), R １ ~R ５ , X １ ~X ３ A, B, k, l, m, and n1 are equivalent to those in formulas (1) to (3) above. In formula (8), Y represents the terminal structure of the copolymer polymer, and the two Ys may be the same or different. Y is a group derived from a reagent (polymerization initiator, chain transfer agent, etc.) used when polymerizing the copolymer polymer, and is usually an organic group having 1 to 20 carbon atoms.

[0041] The arrangement of the silicone macromonomer units, aromatic ring-containing units, and reactive functional group-containing units in the copolymer polymer is not particularly limited and may be in a blocky arrangement or a random arrangement.

[0042] The number-average molecular weight (Mn) of the copolymer polymer of the present invention is not particularly limited, but is preferably 10,000 to 30,000, and more preferably 10,000 to 25,000. When the number-average molecular weight of the copolymer polymer is above these lower limits, the compatibility with silicone resin is improved, and the dispersibility of the filler is enhanced. When the number-average molecular weight of the copolymer polymer is below these upper limits, the viscosity of the copolymer polymer is reduced, and the diffusivity to silicone resin is improved, making it easier to enhance the dispersibility of the filler. From the viewpoint of lowering the viscosity of the copolymer polymer, the molecular weight distribution (Mw / Mn) of the copolymer polymer of the present invention is preferably 5 or less, more preferably 4.5 or less, and even more preferably 4.2 or less. The lower limit of the molecular weight distribution (Mw / Mn) is 1. The molecular weight distribution is the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn). The number-average molecular weight and weight-average molecular weight are standard polystyrene equivalent values ​​obtained by GPC measurement.

[0043] The molecular structure of the copolymer polymer of the present invention is not limited to a structure having linear dimethylsiloxane units (D-isomer), but may also include branched trimethylsiloxane units (T-isomer) or tetrafunctional siloxane units (Q-isomer).

[0044] <Method for producing copolymer polymers> The method for producing copolymer polymers of the present invention is not particularly limited, but includes polymerizing a monomer composition containing a monomer represented by formula (a1), a monomer represented by formula (a2), and a monomer represented by formula (a3).

[0045] In the above equations (a1), (a2), and (a3), R １ ~R ５ , X １ ~X ３ A, B, and n1 are equivalent to those in equations (1) to (3) above.

[0046] Furthermore, as a copolymer polymer, X １ ~X ３ Since it is preferable that each of these has the respective structures of formula (4), formula (5), and formula (7), it is preferable to use (meth)acrylate monomers as monomers when polymerizing the copolymer polymer. That is, the copolymer polymer of the present invention is preferably produced by polymerizing a monomer composition containing the monomer represented by formula (b1), the monomer represented by formula (b2), and the monomer represented by formula (b3). When polymerizing, polymerization initiators, chain transfer agents, etc., that are commonly used for polymerizing (meth)acrylate monomers can be used. In the above equations (b1), (b2), and (b3), R １ ~R ５ A, B, and n1 are equivalent to those in equations (1) to (3) above. Also, R ６ , R ７ , R ９ This is equivalent to the formulas (4), (5), and (7) described above.

[0047] <Resin Composition> In the present invention, a resin composition comprising the copolymer polymer described above, a silicone resin, and an inorganic filler can be provided.

[0048] (Silicone Resin) A specific example of a silicone resin is a curable silicone resin. The curable silicone resin may be either a condensation-curing silicone resin or an addition-reaction-curing silicone resin, but an addition-reaction-curing silicone resin is preferred. The curable silicone resin preferably consists of a silicone resin that constitutes the main component and a silicone resin that constitutes the curing agent for curing the main component. In the case of an addition-reaction-curing silicone resin, the silicone resin used as the main component is preferably an organopolysiloxane having alkenyl groups. The organopolysiloxane having alkenyl groups is more preferably having two or more alkenyl groups. 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 groups, and among these, the vinyl group is 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. Examples of organopolysiloxanes having alkenyl groups include vinyl-terminated polydimethylsiloxanes, vinyl-terminated polyphenylmethylsiloxanes, vinyl-terminated dimethylsiloxane-diphenylsiloxane copolymers, vinyl-terminated dimethylsiloxane-phenylmethylsiloxane copolymers, and vinyl-terminated dimethylsiloxane-diethylsiloxane copolymers.

[0049] The silicone resin used as a curing agent in addition-curing type silicone resins is not particularly limited as long as it can cure the silicone resin that is the main component as described above, but organohydrogenpolysiloxane, which is an organopolysiloxane having hydrosilyl groups (SiH), is preferred. The organohydrogenpolysiloxane preferably has two or more hydrosilyl groups.

[0050] Examples of organohydrogenpolysiloxanes include methylhydrosiloxane-dimethylsiloxane copolymer, polymethylhydrosiloxane, polyethylhydrosiloxane, and methylhydrosiloxane-phenylmethylsiloxane copolymer. These may or may not contain hydrosilyl groups at their terminal ends.

[0051] Furthermore, the silicone resin may be, for example, silicone oil. Examples of silicone oils include methylphenyl silicone oil, dimethyl silicone oil, and modified silicone oil. Silicone oil is liquid at room temperature and atmospheric pressure when compounded, and remains liquid or gel-like when used. In other words, silicone oil is not cured by curing agents, and even if it is cured, it remains liquid or gel-like after curing, making it substantially non-curable. Therefore, when silicone oil is used alone as a resin component, or in a relatively high compounding ratio, it can be used to create paste-like heat dissipation members and other materials formed from the resin composition.

[0052] The silicone resin contained in the resin composition preferably has a viscosity at 25°C of 5 mPa·s to 1000 mPa·s, more preferably 30 mPa·s to 700 mPa·s, and even more preferably 100 mPa·s to 600 mPa·s. The viscosity of the silicone resin is preferably measured using a viscometer (BROOKFIELD rotational viscometer DV-E) with a rotor of spindle No. 14, at a rotation speed of 5 rpm and a measurement temperature of 25°C. By setting the viscosity range of the silicone resin within the above range, the viscosity of the resin composition can be set within a predetermined range, improving the coatability of the resin composition while maintaining a constant shape after coating, making it easy to place on electronic components and the like.

[0053] Furthermore, if the resin composition is a two-component curing type and consists of either one or two components, it may contain either a silicone resin as the main component or a silicone resin as the curing agent, as described above. More specifically, it is preferable that the resin composition contains either an organopolysiloxane having an alkenyl group or an organohydrogenpolysiloxane. However, even if it consists of either one or two components of a two-component curing type, the silicone resin may contain, in addition to the organopolysiloxane having an alkenyl group or organohydrogenpolysiloxane, an organohydrogenpolysiloxane or an organopolysiloxane having an alkenyl group, as long as curing does not progress.

[0054] Furthermore, in the case of a one-component curing type, or in the case of a two-component curing type where the one-component and two-component components are mixed, the resin composition may contain both the main component silicone resin and the curing agent silicone resin. That is, in the case of a one-component curing type, or in the case of a two-component curing type where the one-component and two-component components are mixed, it is preferable that the resin composition contains both an organopolysiloxane having an alkenyl group and an organohydrogenpolysiloxane.

[0055] Furthermore, the curable resin composition may contain a non-curable 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 silicone oil. Of course, the resin composition may also be a non-curable silicone resin composition, in which case, for example, silicone oil may be used alone as the silicone resin.

[0056] (Inorganic Fillers) Inorganic fillers are not particularly limited, but examples include oxides, nitrides, carbides, carbon-based materials, and metal hydroxides. Examples of oxides include metal oxides such as iron oxide, zinc oxide, alumina, 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 and boron 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 carbon-based materials include carbon black, graphite, carbon fiber, graphene, fullerene, carbon nanotubes, carbon nanofibers, and diamond. Examples of metal hydroxides include aluminum hydroxide, calcium hydroxide, and magnesium hydroxide.

[0057] The copolymer polymer of the present invention can disperse π-conjugated fillers well in a silicone resin and improve fluidity; therefore, it is preferable that the inorganic filler contains a π-conjugated filler. The π-conjugated filler is a filler having a π-electron conjugation system such as a six-membered ring structure, and examples include boron nitride and carbon-based materials. Examples of boron nitride include boron nitride nanotubes, boron nitride nanosheets, and hexagonal boron nitride (flaky boron nitride). Examples of carbon-based materials include graphite, carbon black, carbon fibers, and carbon nanotubes. One type of inorganic filler may be used alone, or two or more types may be used in combination.

[0058] The average particle size of the inorganic filler is not particularly limited, but is, for example, 0.5 to 100 μm, preferably 1 to 50 μm, and more preferably 1 to 10 μm. The average particle size refers to the particle size at which the volume integration is 50% (D50) in the particle size distribution of insulating fine particles determined by laser diffraction and scattering.

[0059] The amount of inorganic filler in the resin composition is not particularly limited and can be adjusted as appropriate depending on the application, but is, for example, 10 to 1000 parts by mass, preferably 50 to 900 parts by mass, per 100 parts by mass of silicone resin.

[0060] (Copolymer polymers and other dispersants) Copolymer polymers function as dispersants for dispersing inorganic fillers in silicone resin. The structure of copolymer polymers is as described above, so a detailed explanation is omitted here. The content of copolymer polymers in the resin composition is not particularly limited, but is preferably 5 to 50 parts by mass, and more preferably 15 to 40 parts by mass, per 100 parts by mass of silicone resin.

[0061] The resin composition may contain dispersants other than the copolymer polymer described above. Examples of other dispersants include functional group-containing polymer dispersants having a structure different from that of the copolymer polymer. Examples of functional groups in the functional group-containing polymer dispersants include carboxyl groups, phosphate groups, sulfonic acid groups, carboxylic acid ester groups, phosphate ester groups, sulfonic acid ester groups, hydroxyl groups, amino groups, quaternary ammonium bases, amide groups, etc. Examples of polymers in the functional group-containing polymer dispersants include acrylic, vinyl, polyester, polyurethane, polyether, epoxy, polystyrene, and amino types.

[0062] Furthermore, other dispersants do not have to be polymers; for example, alkoxysilane compounds can also be used. An alkoxysilane compound is a compound having a structure in which one to three of the four bonds of a silicon atom (Si) are bonded to an alkoxy group, and the remaining bond is bonded to an organic substituent. The alkoxy group of an alkoxysilane compound is a hydrolyzable group, and examples include a methoxy group, ethoxy group, protoxy group, butoxy group, pentoxy group, and hexatoxy group. Among these, alkoxysilane compounds having a methoxy group or an ethoxy group are preferred. From the viewpoint of increasing affinity with inorganic fillers, the number of alkoxy groups in an alkoxysilane compound is preferably three. Therefore, it is more preferable that the alkoxysilane compound is at least one selected from trimethoxysilane compounds and triethoxysilane compounds.

[0063] Examples of functional groups included in the organic substituents of alkoxysilane compounds include acryloyl groups, alkyl groups, carboxyl groups, vinyl groups, methacrylic groups, aromatic groups, amino groups, isocyanate groups, isocyanurate groups, epoxy groups, hydroxyl groups, and mercapto groups.

[0064] Alkylalkoxysilane compounds are preferred because they readily blend with silicone resins and improve the dispersibility of inorganic fillers, and they have an alkyl group bonded to a silicon atom. The alkyl group bonded to the silicon atom preferably has four or more carbon atoms. Furthermore, the alkyl group bonded to the silicon atom preferably has 16 or fewer carbon atoms, from the viewpoint of keeping the viscosity of the resin composition low, as the viscosity of the alkoxysilane compound itself is relatively low.

[0065] Preferred alkylalkoxysilane compounds include n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltriethoxysilane, and n-decyltrimethoxysilane. Other alkoxysilane compounds besides alkylalkoxysilanes include 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-isocyanatetopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, and 3-phenylaminopropyltrimethoxysilane.

[0066] The content of other dispersants in the resin composition is, for example, 5 parts by mass or less, preferably 1 part by mass or less, and more preferably 0 parts by mass, per 100 parts by mass of silicone resin.

[0067] The resin composition of the present invention can be applied to various uses depending on the type of inorganic filler. For example, if the inorganic filler is a thermally conductive filler, the resin composition of the present invention can be used as a heat dissipation material; if the inorganic filler is electrically conductive, it can be used as a conductive material; and if the inorganic filler is colorable, such as a pigment, it can be used as a coloring material. As described above, the copolymer polymer in the present invention can improve the fluidity of the filler in the silicone resin, so it is possible to provide a flexible and easy-to-handle resin composition while increasing the content of various fillers.

[0068] The present invention will be clarified below by providing specific examples and comparative examples of the present invention. However, the present invention is not limited to the following examples.

[0069] [Molecular Weight] The measurement conditions for number-average molecular weight and weight-average molecular weight by GPC were as follows: A Waters ACQUITY APC system was used as the GPC instrument, an LF-604 6.0 × 150 mm column was used, and THF was used as the solvent. Measurements were taken at a flow rate of 0.3 mL / min and a temperature of 40°C. A polystyrene standard was used as the standard sample.

[0070] [１ [H-NMR] Measurements were performed using a JEOL "ECX-400" with deuterated chloroform as the solvent, under the following conditions: sample concentration of 1% by weight, temperature of 25°C, measurement frequency of 400 MHz, and 8 integration cycles.

[0071] [Evaluation of piercing load] 50.6 parts by mass of silicone resin (Toray Industries, Inc. "CY-52-291 BASE"), 8.9 parts by mass of copolymer polymer described in each example and comparative example, and 40.5 parts by mass of artificial graphite (Nippon Graphite Co., Ltd. "TGU-15N") were introduced into a container and stirred at 1400 rpm for 1 minute using a planetary stirrer to obtain a resin composition. A piercing rod (with a diameter of 1 mm) having a disc-shaped member with a diameter of 3 mm and a thickness of 1 mm at its tip was pressed into the resin composition introduced into the container from the tip side of the piercing rod at a speed of 10 mm / min (piercing speed), and the load (mN) when the tip of the piercing rod reached a depth of 10 mm from the liquid surface was measured. The material of the piercing rod was stainless steel. The measurement was performed at 25°C. The following criteria were used for evaluation. A lower value of piercing load (mN) indicates higher fluidity of the filler. (Evaluation Criteria) AAA Less than 50 mN AA 50 mN or more but less than 70 mN A 70 mN or more but less than 80 mN B 80 mN or more

[0072] <Example 1> 12.6 g of silicone macromonomer (Shin-Etsu Chemical Co., Ltd. "KF2012"), 0.72 g of polyethylene glycol methacrylate (Tokyo Chemical Industries, Ltd. "PEGMA360"), and 0.6 g of pyrene methyl methacrylate (Angene International Limited) were added to a three-necked flask and completely dissolved with 24 g of toluene. Then, the mixture was purged with nitrogen for 10 minutes using a syringe needle, heated to 80°C, and then 0.56 g of azo polymerization initiator (V-601) was added. The mixture was heated and stirred at 80°C for 18 hours. After the reaction was complete, 50 mL of methanol was added to the beaker containing the solution and stirred for about 5 minutes. After standing for 30 minutes to 1 hour, the supernatant was discarded when the liquid separated into two layers. This process was repeated three times, and the solvent was completely removed to obtain 12 g of the copolymer polymer product. The various structures of copolymer polymers were analyzed using GPC and NMR. The results are shown in Table 1.

[0073] The structures of the monomers used in polymerization in Example 1 are as follows: Silicone macromonomer (left), pyrene methyl methacrylate (center), polyethylene glycol methacrylate (right).

[0074] <Example 2> A copolymer polymer was obtained in the same manner as in Example 1, except that the reaction temperature was changed to 60°C. The results are shown in Table 1.

[0075] <Example 3> A copolymer polymer was obtained in the same manner as in Example 1, except that the amount of pyrene methyl methacrylate was changed to 0.9 g. The results are shown in Table 1.

[0076] <Example 4> A copolymer polymer was obtained in the same manner as in Example 1, except that the amount of pyrene methyl methacrylate was changed to 2.1 g. The results are shown in Table 1.

[0077] <Example 5> A copolymer polymer was obtained in the same manner as in Example 1, except that the amount of polyethylene glycol methacrylate was changed to 2.16 g. The results are shown in Table 1.

[0078] <Example 6> A copolymer polymer was obtained in the same manner as in Example 1, except that the silicone macromonomer was changed to "X-22-174-BX" manufactured by Shin-Etsu Chemical Co., Ltd. The results are shown in Table 1.

[0079] <Example 7> A copolymer polymer was obtained in the same manner as in Example 1, except that the type of silicone macromonomer was changed to the same one as in Example 6, and 1 g of a monomer with the following structure (PEGMA500, manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of the polyethylene glycol methacrylate used in Example 1. The results are shown in Table 1.

[0080] <Example 8> A copolymer polymer was obtained in the same manner as in Example 1, except that 1 g of the same monomer as in Example 7 was used instead of the polyethylene glycol methacrylate used in Example 1. The results are shown in Table 1.

[0081] <Example 9> A copolymer polymer was obtained in the same manner as in Example 1, except that the amount of silicone macromonomer was changed to 37.8 g. The results are shown in Table 1.

[0082] <Example 10> A copolymer polymer was obtained in the same manner as in Example 1, except that the silicone macromonomer was changed to 6.3 g and pyrene methyl methacrylate to 1.2 g. The results are shown in Table 1.

[0083] <Example 11> A copolymer polymer was obtained in the same manner as in Example 1, except that the silicone macromonomer was changed to 9.4 g and PEGMA360 to 2.16 g. The results are shown in Table 1.

[0084] <Example 12> A copolymer polymer was obtained in the same manner as in Example 1, except that the silicone macromonomer was changed to 37.8 g and PEGMA360 to 0.48 g. The results are shown in Table 1.

[0085] <Example 13> A copolymer polymer was obtained in the same manner as in Example 1, except that V-601 was changed to 0.21 g. The results are shown in Table 1.

[0086] <Example 14> A copolymer polymer was obtained in the same manner as in Example 1, except that 1.12 g of V-601 was used and the reaction temperature was changed to 90°C. The results are shown in Table 1.

[0087] <Example 15> A copolymer polymer was obtained in the same manner as in Example 1, except that a monomer with the following structure (CM03, manufactured by Osaka Organic Chemical Industry Co., Ltd.) was used instead of the polyethylene glycol methacrylate used in Example 1, and the reaction solvent was changed to ethyl acetate. The results are shown in Table 1.

[0088] <Example 16> A copolymer polymer was obtained in the same manner as in Example 1, except that 1.6 g of polyethylene glycol methacrylate with 16 repeating units in the oxyethylene portion was used instead of the polyethylene glycol methacrylate used in Example 1. The results are shown in Table 1.

[0089] <Example 17> A copolymer polymer was obtained in the same manner as in Example 1, except that 0.37 g of benzyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of pyrene methyl methacrylate used in Example 1. The results are shown in Table 1. <Example 18> A copolymer polymer was obtained in the same manner as in Example 1, except that the silicone macromonomer was changed to "X-22-2404" manufactured by Shin-Etsu Chemical Co., Ltd., and 18.9 g of it was used. The results are shown in Table 1.

[0090] <Example 19> A copolymer polymer was obtained in the same manner as in Example 1, except that 0.5 g of a monomer with the following structure (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of the polyethylene glycol methacrylate used in Example 1. The results are shown in Table 1.

[0091] <Example 20> A copolymer polymer was obtained in the same manner as in Example 1, except that 1.11 g of 11-[4-(4-butylphenylazo)phenoxy]undecyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of pyrene methyl methacrylate used in Example 1. The results are shown in Table 1.

[0092] <Comparative Example 1> A copolymer polymer was obtained in the same manner as in Example 1, except that pyrene methyl methacrylate was not used. The results are shown in Table 1.

[0093] <Comparative Example 2> A copolymer polymer was obtained in the same manner as in Example 1, except that polyethylene glycol methacrylate was not used. The results are shown in Table 1.

[0094] <Comparative Example 3> A copolymer polymer was obtained in the same manner as in Example 1, except that a silicone macromonomer was not used. The results are shown in Table 1.

[0095] <Comparative Example 4> Various evaluations were performed using the following compounds. The results are shown in Table 1. n = 210

[0096] <Comparative Example 5> A copolymer polymer was obtained in the same manner as in Example 1, except that the silicone macromonomer was changed to "X-22-174-BX" (number average molecular weight 1,000) manufactured by Shin-Etsu Chemical Co., Ltd. The results are shown in Table 1.

[0097]

[0098] The copolymer polymer in each example is the copolymer monomer of the present invention, having a silicone macromonomer unit represented by formula (1), an aromatic ring-containing unit represented by formula (2), and a reactive functional group-containing unit represented by formula (3), and having a number-average molecular weight (Mn) of 3000 or more of the silicone macromonomer unit. Because this copolymer polymer has two filler linkers, the aromatic ring-containing unit and the reactive functional group-containing unit, it exhibits high adsorption to π-conjugated fillers. Furthermore, evaluation results of the puncture load showed that the resin composition using the copolymer monomer of the present invention exhibited a small puncture load, indicating improved dispersibility of π-conjugated fillers in the silicone resin and increased fluidity. On the other hand, Comparative Examples 1 to 3 are copolymer polymers that do not have any of the units represented by formula (1), formula (2), or formula (3). Comparative Example 4 is not a copolymer, but a linear polymer having a polysiloxane structure, and is a polymer having a condensed ring compound at its terminal. Comparative Example 5 is a copolymer polymer having each of the units of formulas (1) to (3), but the number-average molecular weight of the silicone macromonomer unit of formula (1) is low at 1000. Since all of the polymers in Comparative Examples 1 to 5 have a different structure from the copolymer polymer of the present invention, it was found that the puncture load values ​​of the resin compositions were high and the fluidity was low.

Claims

1. A copolymer polymer having a silicone macromonomer unit represented by the following formula (1), an aromatic ring-containing unit represented by formula (2), and a reactive functional group-containing unit represented by formula (3), wherein the number average molecular weight (Mn) of the silicone macromonomer unit is 1,500 or more. (In formulas (1) to (3), R １ , R ２ , R ３ are each independently a hydrogen atom or a methyl group, R ４ and R ５ are each independently a hydrocarbon group having 1 to 6 carbon atoms, and a plurality of R ４ may be the same or different from each other, n1 is 10 or more, X １ , X ２ , X ３ are each independently an organic group having 1 to 20 carbon atoms, A is a group containing an aromatic ring, B is a group containing a reactive functional group, k represents the number of silicone macromonomer units in the copolymer polymer, l represents the number of aromatic ring-containing units in the copolymer polymer, m represents the number of reactive functional group-containing units in the copolymer polymer, and k, l, and m are each values exceeding 0.) 2. The copolymer polymer according to claim 1, wherein the ratio of l to k (l / k) is 0.2 or more and 3 or less.

3. The copolymer polymer according to claim 1 or 2, wherein the reactive functional group of B has hydrogen bonding properties.

4. The copolymer polymer according to claim 1 or 2, wherein the weight ratio of the silicone macromonomer unit represented by the following formula (I) to the reactive functional group-containing unit is 5 or more and 80 or less. (Number average molecular weight of the silicone macromonomer unit × k) / (Number average molecular weight of the reactive functional group-containing unit × m) Formula (I) 5. The copolymer polymer according to claim 1 or 2, wherein the number average molecular weight (Mn) is 10,000 or more and 30,000 or less, and the molecular weight distribution (Mw / Mn) is 5 or less.

6. A resin composition comprising the copolymer polymer according to claim 1 or 2, a silicone resin, and an inorganic filler.

7. The resin composition according to claim 6, wherein the inorganic filler comprises a π-conjugated filler.

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