Method for producing curable composition and mixture for curable composition

Abstract

One embodiment of the present invention relates to a method for producing a curable composition, the method comprising: mixing a liquid A, which contains a solvent and a compound having a vinylphenyl group, with a polymerization inhibitor B to obtain a liquid B, and removing the solvent from the liquid B to obtain a mixture containing a compound having a vinylphenyl group and the polymerization inhibitor B; and obtaining a curable composition by using the mixture.

Description

Method for producing curable composition and mixture for curable composition

[0001] The present disclosure relates to a method for producing a curable composition and a mixture for the curable composition.

[0002] Semiconductor devices are used in a variety of electronic devices. As electronic devices become smaller, lighter, and more sophisticated, the amount of heat generated by semiconductor devices that handle large amounts of information at high speeds increases. Furthermore, in recent years, semiconductor devices have increasingly been used in high-current or high-voltage environments, such as in cars, trains, wind power generation, and solar power generation. The larger the current or voltage, the greater the amount of heat generated by the semiconductor device. Accordingly, the heat resistance of semiconductor devices has become increasingly important.

[0003] Conventionally, in semiconductor devices, a cured product of a thermosetting resin composition containing a thermosetting resin, a curing agent, and an inorganic filler has been widely used as an encapsulant for semiconductor elements because it has excellent heat resistance, moldability, productivity, mechanical properties, and the like (see Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2021-130743

[0005] Generally, in order to obtain a cured product with excellent heat resistance, it is desirable that the thermosetting resin has high reactivity and the thermosetting resin composition has good curability. High reactivity of the thermosetting resin can increase the crosslink density of the cured product, thereby improving the heat resistance of the cured product. On the other hand, high reactivity of the thermosetting resin can reduce the fluidity of the thermosetting resin composition during molding, which can result in reduced moldability, productivity, etc.

[0006] Therefore, the present disclosure provides a method for producing a curable composition having high fluidity from the viewpoints of moldability, productivity, etc. The present disclosure also provides a mixture used in the curable composition having high fluidity.

[0007] The present invention includes the following embodiments. The present invention is not limited to the following embodiments. One embodiment relates to a method for producing a curable composition, comprising: mixing a liquid A containing a compound having a vinylphenyl group and a solvent with a polymerization inhibitor B to obtain a liquid B, removing the solvent from the liquid B to obtain a mixture containing the compound having a vinylphenyl group and the polymerization inhibitor B; and using the mixture to obtain a curable composition. Another embodiment relates to a mixture for a curable composition, which contains a compound having a vinylphenyl group and the polymerization inhibitor B, has a solvent content of 1.0 mass% or less, and has a viscosity at 60°C of 5.0 Pa s or less.

[0008] According to the present disclosure, it is possible to provide a method for producing a curable composition having high fluidity, and also to provide a mixture for use in the curable composition having high fluidity.

[0009] The following describes embodiments of the present invention. The present invention is not limited to the following embodiments. The following embodiments can be implemented alone or in combination. Combinations of multiple embodiments are also included in the present invention.

[0010] In the present disclosure, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in the present disclosure, the upper or lower limit of a certain numerical range may be replaced with the upper or lower limit of another numerical range. The upper or lower limit of a numerical range described in the present disclosure may be replaced with a value shown in the Examples. A stepped numerical range may be created by selecting a numerical value from the upper and lower limit numerical values ​​described in stages in the present disclosure. The upper and lower limit numerical values ​​described in the present disclosure may be replaced with a value shown in the Examples. In the present disclosure, each component may contain multiple corresponding substances. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified. In the present disclosure, each structure in the polymer may contain multiple corresponding structures. When a polymer contains multiple structures corresponding to each structure, the content or amount of each structure refers to the total content or amount of the multiple structures present in the polymer, unless otherwise specified. In the present disclosure, the particles corresponding to each component may contain multiple types of particles. When a composition contains multiple types of particles corresponding to each component, the particle size of each component refers to the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified. In the present disclosure, the term "process" includes not only processes that are independent of other processes, but also processes that cannot be clearly distinguished from other processes, as long as the intended effect of the process is achieved.

[0011] <Method for Producing Curable Composition> The method for producing a curable composition includes mixing a liquid A containing a compound having a vinylphenyl group and a solvent with a polymerization inhibitor B to obtain a liquid B, removing the solvent from the liquid B to obtain a mixture containing the compound having a vinylphenyl group and the polymerization inhibitor B (sometimes referred to as "step (1)" in the present disclosure); and obtaining a curable composition using the mixture (sometimes referred to as "step (2)" in the present disclosure). The method for producing a curable composition may further include an optional step as necessary. For example, step (2) may be mixing the mixture with a polymerization inhibitor C to obtain a curable composition. In the present disclosure, a compound having a vinylphenyl group is sometimes referred to as a "vinylphenyl compound." Liquid A may contain the polymerization inhibitor A. Liquid A, Liquid B, the mixture, and the curable composition may contain optional components. The polymerization inhibitor A, the polymerization inhibitor B, and the polymerization inhibitor C may each be present in a state combined with the vinylphenyl compound and a component that may be optionally contained in the liquid A, liquid B, the mixture, or the curable composition.

[0012] [Step (1)] In step (1), Liquid A containing a compound having a vinylphenyl group and a solvent is mixed with a polymerization inhibitor B to obtain Liquid B, and the solvent is removed from Liquid B to obtain a mixture containing the vinylphenyl compound and the polymerization inhibitor B. In Liquid A, the vinylphenyl compound is dissolved or dispersed in the solvent. Liquid A can be a solution. Liquid A can be a commercially available product or a liquid prepared using the vinylphenyl compound and a solvent. The vinylphenyl compound used in the preparation can be a commercially available product or a synthesized compound. The solvent contained in Liquid A can be, for example, the solvent used in synthesizing the vinylphenyl compound. Liquid A can be, for example, a liquid obtained by synthesis using raw material compounds and a solvent, containing the vinylphenyl compound and the solvent used in the synthesis. In this case, for example, the liquid obtained after synthesis can be used as Liquid A as is, or a liquid obtained by removing a portion of the vinylphenyl compound, a portion of the solvent used in the synthesis, or a portion of the vinylphenyl compound and a portion of the solvent used in the synthesis from the liquid obtained after synthesis can be used as Liquid A. Alternatively, a solvent may be added to the liquid obtained after synthesis, or to a liquid obtained by removing a portion of the liquid obtained after synthesis, and the resulting mixture may be used as Liquid A. The vinylphenyl compound can be synthesized, for example, by a method using styrene having a halogenated methyl group, which will be described later. Liquid A may contain a polymerization inhibitor A.

[0013] The solvent content in Liquid A is, for example, 20 to 60% by mass, 30 to 50% by mass, or 35 to 45% by mass, based on the mass of Liquid A. When the solvent content is 60% by mass or less, the time required to remove the solvent can be shortened, and when removing the solvent by heating, the heating temperature can be lowered. As a result, an increase in the molecular weight and viscosity of the vinylphenyl compound tend to be suppressed. When the solvent content is 20% by mass or more, mixing of Liquid A and the polymerization inhibitor B tends to be facilitated. The vinylphenyl compound content is, for example, 40 to 80% by mass, 50 to 70% by mass, or 55 to 65% by mass, based on the mass of Liquid A. When the vinylphenyl compound content is 80% by mass or less, mixing of Liquid A and the polymerization inhibitor B tends to be facilitated. When the vinylphenyl compound content is 40% by mass or more, the solvent can be removed from Liquid B at a low temperature in a short time, which tends to suppress an increase in the molecular weight and viscosity of the vinylphenyl compound.

[0014] In Liquid A, the content of the vinylphenyl compound is, based on the mass of the solid content contained in Liquid A, for example, 95.00 to 100.00 mass %, 99.00 to 99.99 mass %, or 99.20 to 99.90 mass %.

[0015] The method for mixing liquid A and polymerization inhibitor B is not particularly limited. Examples of methods include adding polymerization inhibitor B to liquid A and stirring; adding a liquid containing polymerization inhibitor B and a solvent to liquid A and stirring; adding liquid A to polymerization inhibitor B and stirring; and adding liquid A to a liquid containing polymerization inhibitor B and a solvent and stirring. The amount of polymerization inhibitor B used is, for example, 0.05 to 2.00 mass%, 0.10 to 1.50 mass%, or 0.50 to 1.00 mass%, based on the mass of the vinylphenyl compound. When the amount of polymerization inhibitor B used is 0.05 mass% or more, it tends to be possible to suppress an increase in the molecular weight and viscosity of the vinylphenyl compound. Furthermore, the resulting mixture tends to exhibit good storage stability. When the amount of polymerization inhibitor B used is 2.00 mass% or less, it tends to be possible to suppress a decrease in the curability of the curable composition.

[0016] The solvent content of Liquid B is, for example, 20 to 60% by mass, 30 to 50% by mass, or 35 to 45% by mass, based on the mass of Liquid B. When the solvent content is 60% by mass or less, the time required to remove the solvent can be shortened, and when removing the solvent by heating, the heating temperature can be lowered. As a result, an increase in the molecular weight and viscosity of the vinylphenyl compound tend to be suppressed. When the solvent content is 20% by mass or more, Liquid B tends to become a homogeneous solution or dispersion. The vinylphenyl compound content is, for example, 40 to 80% by mass, 50 to 70% by mass, or 55 to 65% by mass, based on the mass of Liquid B. When the vinylphenyl compound content is 80% by mass or less, Liquid B tends to become a homogeneous solution or dispersion. When the vinylphenyl compound content is 40% by mass or more, the solvent can be removed at a low temperature in a short time, which tends to suppress an increase in the molecular weight and viscosity of the vinylphenyl compound.

[0017] In Liquid B, the content of the vinylphenyl compound is, for example, 95.00 to 100.00 mass %, 99.00 to 99.99 mass %, or 99.20 to 99.80 mass %, based on the mass of the solid content contained in Liquid B.

[0018] An example of a method for removing the solvent from Liquid B is a method of evaporating the solvent. The solvent can be evaporated and removed by placing Liquid B under a reduced pressure, heating, or a combination of these. The mixture obtained after removing the solvent contains the vinylphenyl compound and the polymerization inhibitor B.

[0019] The solvent can be removed under normal pressure or under reduced pressure. The pressure is, for example, 0.1 MPa or less. The pressure may be 0.05 MPa or more. The solvent can be removed by heating Liquid B. The heating temperature is, for example, 40°C or more, 50°C or more, or 60°C or more. The heating temperature may be 100°C or less. A general vacuum dryer used to dry compounds can be used to remove the solvent.

[0020] The amount of solvent remaining in the mixture is, for example, 1.0% by mass or less, based on the mass of the mixture. When the amount of solvent is 1.0% by mass or less, the occurrence of voids and cracks can be prevented. The amount of solvent may be 0.8% by mass or less, 0.6% by mass or less, or 0.5% by mass or less. The amount of solvent can be measured according to the method described in the examples.

[0021] The vinylphenyl compound contained in the mixture may include the vinylphenyl compound itself, a polymer, a decomposition product, etc., contained in Liquid A or Liquid B. The polymerization inhibitor B may be present in the mixture in a state bound to other components such as the vinylphenyl compound and optional components that may be contained.

[0022] The difference in weight-average molecular weight between the vinylphenyl compound contained in Liquid A or Liquid B and the vinylphenyl compound contained in the mixture obtained by removing the solvent is, for example, 700 or less. The smaller the difference in weight-average molecular weight, the more the polymerization reaction of the vinylphenyl compound is suppressed during the solvent removal process. The difference in weight-average molecular weight may be 600 or less, 400 or less, 100 or less, or 50 or less. The weight-average molecular weight can be measured according to the method described in the Examples. The difference in weight-average molecular weight can be calculated using the formula: Difference in weight-average molecular weight = (weight-average molecular weight of the mixture obtained by removing the solvent) - (weight-average molecular weight of the vinylphenyl compound before removing the solvent). The difference in weight-average molecular weight may be, for example, -100 or more, -50 or more, or 0 or more.

[0023] The viscosity of the mixture at 60°C is, for example, 5.0 Pa·s or less. When the viscosity of the mixture at 60°C is 5.0 Pa·s or less, the curable composition tends to have good fluidity. The viscosity of the mixture at 60°C may be 4.0 Pa·s or less, 3.0 Pa·s or less, 2.0 Pa·s or less, or 1.0 Pa·s or less. The viscosity of the mixture at 60°C can be measured according to the method described in the Examples. The viscosity of the mixture at 60°C may be, for example, 0.1 Pa·s or more, 0.2 Pa·s or more, or 0.3 Pa·s or more.

[0024] The mixture containing the vinylphenyl compound and the polymerization inhibitor B can be used as a mixture for a curable composition for producing a curable composition. The mixture for a curable composition contains a compound having a vinylphenyl group and the polymerization inhibitor B, and has, for example, a solvent content of 1.0 mass% or less and a viscosity at 60°C of 5.0 Pa s or less.

[0025] [Step (2)] In step (2), a curable composition is obtained using the mixture. For example, in step (2), the mixture is mixed with a polymerization inhibitor C to obtain a curable composition. The mixture, the polymerization inhibitor C, and optional components such as a compound having a vinyl bond, a filler, and a solvent, as described below, may be mixed to obtain a curable composition.

[0026] The amount of polymerization inhibitor C used is, for example, 1.0 to 20.0 mass%, 5.0 to 18.0 mass%, or 10.0 to 15.0 mass%, based on the vinylphenyl compound. When the content of polymerization inhibitor C is 1.0 mass% or more, it tends to be possible to suppress reactions between vinylphenyl compounds or between vinylphenyl compounds and other components such as vinyl compounds described below. When the content of polymerization inhibitor C is 20.0 mass% or less, it tends to be possible to suppress a decrease in the curability of the curable composition.

[0027] When the curable composition does not contain a solvent, for example, a method can be used in which predetermined amounts of the vinylphenyl compound, the polymerization inhibitor C, and any optional components are thoroughly mixed using a mixer or the like, followed by melt-kneading, cooling, and pulverization. For melt-kneading, kneaders such as twin-screw kneaders; rolls such as mixing rolls; extruders such as extruders, and the like can be used. The melt-kneading temperature is, for example, 70 to 140°C, or 80 to 130°C. The curable composition may be solid at room temperature and normal pressure (e.g., 25°C, atmospheric pressure). The shape of the solid curable composition is not particularly limited, and examples include powder, granules, tablets, and the like.

[0028] When the curable composition contains a solvent, for mixing, for example, a ball-type mixer such as a ball mill, sand mill, bead mill, paint shaker, or rocking mill; a blade-type mixer such as a kneader, paddle mixer, planetary mixer, or Henschel mixer; a roll-type mixer such as a three-roll mixer; a Raikai mixer; or a colloid mill can be used.

[0029] [Raw Materials, etc.] Examples of optional components such as the vinylphenyl compound, solvent, polymerization inhibitor B, and polymerization inhibitor C used as needed are as described below in the description of the curable composition. The solvent may be an aromatic solvent or toluene. The polymerization inhibitor A preferably contains at least one selected from a TEMPO compound and a phenothiazine compound, more preferably a phenothiazine compound. The polymerization inhibitor B preferably contains at least one selected from a TEMPO compound and a phenothiazine compound, more preferably a TEMPO compound. The polymerization inhibitor C preferably contains at least one selected from a TEMPO compound and a phenothiazine compound, more preferably a TEMPO compound. Both the polymerization inhibitor B and the polymerization inhibitor C may contain a TEMPO compound.

[0030] <Curable composition> The curable composition contains at least a compound having a vinylphenyl group (vinylphenyl compound) and a polymerization inhibitor. The curable composition may further contain a compound having a vinyl bond. In the present disclosure, a compound having a vinyl bond is a compound different from a compound having a vinylphenyl group, and is a compound that does not fall under the category of a compound having a vinylphenyl group. A compound having a vinyl bond does not have a vinylphenyl group. In the present disclosure, a compound having a vinyl bond may be referred to as a "vinyl compound".

[0031] [Compound Having a Vinylphenyl Group] A vinylphenyl compound is a compound having at least one vinylphenyl group. The vinylphenyl compound has, for example, 1 to 20, 1 to 15, or 1 to 10 vinylphenyl groups. The vinylphenyl compound may consist of one type of vinylphenyl compound or may contain two or more types of vinylphenyl compounds. When a curable composition contains a vinylphenyl compound, the heat resistance of the cured product is improved. One reason for this is the high reactivity of the vinylphenyl compound. High reactivity of the vinylphenyl compound facilitates sufficient curing reaction of the curable composition. As a result, the crosslink density of the resulting cured product increases, thereby increasing the thermal decomposition temperature and improving heat resistance. In some embodiments, an increased crosslink density also reduces the amount of expansion of the cured product with increasing temperature. A smaller amount of expansion can suppress warping of electronic component devices. However, these are speculations, and the present invention is not limited by these speculations.

[0032] The vinylphenyl group can be represented by any of the following formulas: From the viewpoint of obtaining a cured product with a low dielectric constant and dielectric dissipation factor, the vinylphenyl compound may contain a compound having a group represented by formula (p): * indicates the bonding position to other atoms.

[0033] In the total amount of vinylphenyl compounds contained in the curable composition, the ratio of groups represented by formula (p), groups represented by formula (m), and groups represented by formula (o) (molar ratio of groups represented by formula (p): groups represented by formula (m): groups represented by formula (o)) is, for example, 40 to 100: 0 to 60: 0 to 60, 70 to 90: 0: 10 to 30, or 40 to 60: 40 to 60: 0. The greater the ratio of groups represented by formula (p), the lower the dielectric constant and dielectric dissipation factor of the cured product tend to be.

[0034] The vinylphenyl compound may be a compound having a vinylphenylmethyl group (also referred to as a "vinylbenzyl group"). In the present disclosure, a compound having a vinylbenzyl group may be referred to as a "vinylbenzyl compound". The vinylbenzyl compound is an example of a vinylphenyl compound. The vinylphenyl compound may be a compound having a vinylphenylmethyloxy group (also referred to as a "vinylbenzyl ether group"). In the present disclosure, a compound having a vinylbenzyl ether group may be referred to as a "vinylbenzyl ether compound". The vinylbenzyl ether compound is an example of a vinylbenzyl compound and a vinylphenyl compound.

[0035] The vinylphenyl compound may be a monomer or polymer capable of radical polymerization. The vinylphenyl compound includes, for example, a monomer having a vinylphenyl group. In the present disclosure, a monomer having a vinylphenyl group may be referred to as a "vinylphenyl group-containing monomer." The vinylphenyl compound includes, for example, a polymer having a vinylphenyl group. In the present disclosure, a polymer having a vinylphenyl group may be referred to as a "vinylphenyl group-containing polymer." In the present disclosure, a monomer may be a compound that does not contain a repeating structural unit. A polymer may be a compound that contains a repeating structural unit. A polymer may be a polymer with a low degree of polymerization (i.e., an oligomer) or a polymer with a high degree of polymerization.

[0036] In some embodiments, the vinyl phenyl compound includes a compound having two vinyl phenyl groups. The compound having two vinyl phenyl groups may be a monomer or a polymer. In some embodiments, the vinyl phenyl compound includes a compound having three or more vinyl phenyl groups. The compound having three or more vinyl phenyl groups may be a monomer or a polymer.

[0037] The vinylphenyl compound includes, for example, a compound having a structural unit represented by the following formula (Bb): (In the formula, X represents an organic group; each B independently represents a group containing a vinylphenyl group; each R independently represents a substituent; l represents an integer of 1 to 5; m represents an integer of 0 to 10; and * represents the bonding position to another atom.)

[0038] The term "independently" with respect to B means that, for example, when l is 2 or more and the structural unit represented by formula (Bb) has a plurality of Bs, the plurality of Bs may be the same "group containing a vinylphenyl group", or some or all of the Bs may be different "groups containing a vinylphenyl group". In this case, "independently" does not preclude l from being 1, and the structural unit represented by formula (Bb) may be a structural unit having one "group containing a vinylphenyl group". In the present disclosure, "(B) ｌ The same applies to statements similar to ".

[0039] Examples of X include X ｂ１ and X Ｂ１ Examples of the compound having a structural unit represented by formula (Bb) include a compound represented by formula (b1) described below and a polymer represented by formula (B1) described below.

[0040] (Vinylphenyl Group-Containing Monomer) In some embodiments, the vinylphenyl compound includes a vinylphenyl group-containing monomer. The vinylphenyl group-containing monomer includes a monomer having two vinylphenyl groups and may further include at least one selected from the group consisting of a monomer having one vinylphenyl group and a monomer having three vinylphenyl groups; or may include a monomer having two vinylphenyl groups, a monomer having one vinylphenyl group, and a monomer having three vinylphenyl groups. When the vinylphenyl group-containing monomer includes two or more vinylphenyl group-containing monomers, the average number of vinylphenyl groups contained in the vinylphenyl group-containing monomer is, for example, 1.2 to 2.8, 1.4 to 2.7, or 1.6 to 2.6.

[0041] The vinylphenyl group-containing monomer may further have an aromatic ring. The vinylphenyl group-containing monomer may have only one aromatic ring, or two or more aromatic rings. The number of carbon atoms in the aromatic ring may be, for example, 2 to 30, 6 to 20, or 9 to 15. The aromatic ring may be an aromatic hydrocarbon ring or an aromatic heterocyclic ring. The aromatic ring may be a monocyclic ring or a condensed polycyclic ring. Examples of aromatic hydrocarbon rings include benzene, naphthalene, anthracene, tetracene, fluorene, phenanthrene, indene, indane, and biphenylene. Examples of aromatic heterocyclic rings include pyridine, pyrazine, quinoline, isoquinoline, acridine, phenanthroline, furan, pyrrole, thiophene, carbazole, oxazole, oxadiazole, thiadiazole, triazole, benzoxazole, benzoxadiazole, benzothiadiazole, benzotriazole, and benzothiophene. From the viewpoint of the dielectric properties of the cured product, the aromatic ring may be an aromatic hydrocarbon ring or a fused polycyclic aromatic hydrocarbon ring. From the viewpoint of the dielectric constant and the dielectric loss tangent, the aromatic ring may be, for example, fluorene or indene; or may be indene. When the vinylphenyl group-containing monomer contains indene, it tends to be possible to obtain a cured product exhibiting a lower dielectric constant and dielectric loss tangent.

[0042] The aromatic ring, the aromatic hydrocarbon ring, the aromatic heterocycle, and the fused polycyclic aromatic hydrocarbon ring, which are examples of the aromatic ring, as well as the rings specifically mentioned above, may all be substituted or unsubstituted. In the case of substitution, examples of the substituent include an alkyl group, an alkenyl group, an aryl group, a heteroaryl group, and a monovalent group formed by bonding two or more groups selected from these. The number of carbon atoms in the alkyl group and the alkenyl group may be 1 to 18, 2 to 12, or 3 to 6. The number of carbon atoms in the aryl group and the heteroaryl group may be 2 to 30, 6 to 20, or 9 to 15. Examples of the monovalent group include an alkylaryl group, an arylalkyl group, and an alkylarylalkyl group.

[0043] The vinylphenyl group-containing monomer may include, for example, a monomer having one aromatic ring and 1 to 3 vinylphenyl groups bonded to the aromatic ring directly or via a linking group; a monomer having one aromatic hydrocarbon ring and 1 to 3 vinylphenyl groups bonded to the aromatic hydrocarbon ring directly or via a linking group; or a monomer having one indene ring and 1 to 3 vinylphenyl groups bonded to the indene ring directly or via a linking group. In these embodiments, the aromatic ring, aromatic hydrocarbon ring, and indene ring may each be substituted or unsubstituted. Examples of substituents are as described above. The linking group may be, for example, a group selected from the group consisting of an alkylene group (having, for example, 1 to 5 carbon atoms), an oxy group, a thio group, a sulfonyl group, a sulfinyl group, a carbonyl group, a carbonyloxy group, an imino group, and a divalent group formed by bonding two or more groups selected from these. The phrase "having one aromatic ring and 1 to 3 vinylphenyl groups bonded to the aromatic ring via linking groups" means "having one aromatic ring and 1 to 3 'linking groups bonded to the aromatic ring and 1 to 3 vinylphenyl groups bonded to the linking groups'."

[0044] The vinylphenyl group-containing monomer may have a saturated or unsaturated aliphatic hydrocarbon group, a saturated or unsaturated alicyclic hydrocarbon group, a group containing a hetero atom, or the like, instead of or in addition to the aromatic ring.

[0045] The weight average molecular weight (Mw) of the vinylphenyl group-containing monomer is, for example, 200 to 2,000, 200 to 1,000, 200 to 800, 250 to 750, or 300 to 700 from the viewpoint of moldability and handleability. In the present disclosure, the weight average molecular weight (Mw) and number average molecular weight (Mn) refer to values ​​measured in polystyrene equivalent terms by gel permeation chromatography (GPC). Specifically, the weight average molecular weight (Mw) and number average molecular weight (Mn) in the present disclosure can be measured by the method described in the examples.

[0046] In some embodiments, the vinyl phenyl compound includes a compound represented by formula (b1): (In the formula, X ｂ１ represents an organic group, each B independently represents a group containing a vinylphenyl group, 1 represents an integer of 1 to 5, each R independently represents a substituent, and m represents an integer of 0 to 5.

[0047] The organic group may be a group containing at least one carbon atom, for example, a group containing at least one selected from the group consisting of saturated aliphatic hydrocarbon groups, unsaturated aliphatic hydrocarbon groups, saturated alicyclic hydrocarbon groups, unsaturated alicyclic hydrocarbon groups, aromatic hydrocarbon ring groups, and aromatic heterocyclic groups. The organic group may or may not further contain a group containing a heteroatom. The organic group may be, for example, an aromatic hydrocarbon ring group or an aromatic heterocyclic group; or it may be an aromatic hydrocarbon ring group. Examples of the aromatic hydrocarbon ring in the aromatic hydrocarbon ring group and the aromatic heterocyclic ring in the aromatic heterocyclic group are as described above.

[0048] l may be 1 to 3. The vinylphenyl group-containing monomer, for example, in formula (b1), includes a compound in which l is 2, and may further include at least one compound selected from the group consisting of a compound in which l is 1 and a compound in which l is 3; or may include a compound in which l is 2, a compound in which l is 1, and a compound in which l is 3. When the vinylphenyl group-containing monomer includes multiple compounds represented by formula (b1), the average value of l in the compounds represented by formula (b1) is, for example, 1.2 to 2.8, 1.4 to 2.7, or 1.6 to 2.6.

[0049] Examples of the substituent represented by R include alkyl groups, alkenyl groups, aryl groups, heteroaryl groups, and monovalent groups formed by the bonding of two or more selected from these. The number of carbon atoms in the alkyl and alkenyl groups may be 1 to 18, 2 to 12, or 3 to 6. The number of carbon atoms in the aryl and heteroaryl groups may be 2 to 30, 6 to 20, or 9 to 15. Examples of the monovalent group include alkylaryl groups, arylalkyl groups, and alkylarylalkyl groups. m may be 0 to 2, or 0 or 1. When the vinylphenyl group-containing monomer contains multiple compounds represented by formula (b1), the average value of m in the compounds represented by formula (b2) is, for example, 0.0 to 1.8, 0.0 to 1.6, or 0.0 to 1.4. In some embodiments, the average value of m may be greater than 0.0, 0.1 or greater, 0.5 or greater, or 1.0 or greater.

[0050] In some embodiments, the vinyl phenyl compound includes a compound represented by the following formula (b2): When the vinyl phenyl compound includes a compound represented by the following formula (b2), better heat resistance tends to be obtained. (In the formula, X ｂ２ represents an aromatic hydrocarbon ring group, B ｐ each independently represents a group represented by the following formula (Ph), each L independently represents a direct bond or a linking group, 1 represents an integer of 1 to 3, each R independently represents a substituent, and m represents an integer of 0 to 3. (In the formula, * represents the bonding position.)

[0051] Examples of the aromatic hydrocarbon ring in the aromatic hydrocarbon ring group are as described above. ｂ２ may be, for example, a fused polycyclic aromatic hydrocarbon ring group.

[0052] Examples of the linking group are as described above. The linking group may be, for example, an alkylene group (having, for example, 1 to 5 carbon atoms) or a methylene group. ｂ２ and B ｐ The same applies to descriptions similar to "L is a direct bond" in the present disclosure.

[0053] The vinylphenyl group-containing monomer may, for example, in formula (b2), include a compound in which l is 2, and may further include at least one compound selected from the group consisting of a compound in which l is 1 and a compound in which l is 3; or may include a compound in which l is 2, a compound in which l is 1, and a compound in which l is 3. When the vinylphenyl group-containing monomer includes multiple types of compounds represented by formula (b2), the average value of l in the compounds represented by formula (b2) is, for example, 1.2 to 2.8, 1.4 to 2.7, or 1.6 to 2.6.

[0054] Examples of the substituent represented by R are as set forth in formula (b1). m may be 0 to 2, or 0 or 1. When the vinylphenyl group-containing monomer includes multiple compounds represented by formula (b1), the average value of m in the compounds represented by formula (b2) is, for example, 0.0 to 1.8, 0.0 to 1.6, or 0.0 to 1.4. In some embodiments, the average value of m may be greater than 0.0, 0.1 or greater, 0.5 or greater, or 1.0 or greater.

[0055] From the viewpoint of obtaining a cured product having a low dielectric constant and a low dielectric loss tangent, the group represented by formula (Ph) may include a group represented by formula (p) above.

[0056] In some embodiments, the vinyl phenyl compound includes a compound represented by the following formula (b3): ​​When the vinyl phenyl compound includes a compound represented by the following formula (b3), better heat resistance is obtained, the expansion amount is small, and further, a low dielectric constant and a low dielectric loss tangent tend to be obtained. (In the formula, B ｈｂ each independently represents a hydrogen atom, a group represented by the following formula (Ba), or a group represented by the following formula (Bz), and at least one B ｈｂ is a group represented by the following formula (Bz). (In the formula, A represents an alkyl group, and * represents a bonding position.) (In the formula, * represents the bonding position.)

[0057] The alkyl group represented by A has, for example, 1 to 6 carbon atoms.

[0058] The vinylphenyl group-containing monomer may include a compound of formula (b3) in which the number of groups represented by formula (Bz) is 2, and may further include at least one selected from the group consisting of a compound in which the number of groups represented by formula (Bz) is 1 and a compound in which the number of groups represented by formula (Bz) is 3; or may include a compound in which the number of groups represented by formula (Bz) is 2, a compound in which the number of groups represented by formula (Bz) is 1, and a compound in which the number of groups represented by formula (Bz) is 3. When the vinylphenyl group-containing monomer includes multiple compounds of formula (b3), the average number of groups represented by formula (Bz) in the compounds represented by formula (b3) is, for example, 1.2 to 2.8, 1.4 to 2.7, or 1.6 to 2.6. The average number of groups represented by formula (Ba) in the compounds represented by formula (b3) is, for example, 0.0 to 1.8, 0.0 to 1.6, or 0.0 to 1.4. In some embodiments, the average number of groups represented by formula (Ba) may be greater than 0.0, 0.1 or more, 0.5 or more, or 1.0 or more.

[0059] From the viewpoint of obtaining a cured product having a low dielectric constant and a low dielectric loss tangent, the group represented by formula (Bz) may include a group represented by formula (Bz) in which the bonding position of the vinyl group to the benzene ring is para to the bonding position of the methylene group to the benzene ring.

[0060] The method for synthesizing the vinylphenyl group-containing monomer is not particularly limited. For example, when the vinylphenyl group-containing monomer is a compound represented by formula (b2), a method of reacting an aromatic hydrocarbon ring with a styrene having a halogenated methyl group in the presence of a basic compound can be mentioned. When synthesized by this method, the compound represented by formula (b2) has a methylene group as a linking group.

[0061] Examples of styrenes having a halogenated methyl group include o-chloromethylstyrene, m-chloromethylstyrene, and p-chloromethylstyrene, and these can be used alone or in combination of two or more. Examples of basic compounds include alkali metal hydroxides and alkali metal alkoxides. A phase transfer catalyst may be used in this reaction. Examples of phase transfer catalysts include tetrabutylphosphonium bromide and tetra-n-butylammonium bromide. The reaction can be carried out in a solvent. The reaction may be carried out under heating and stirring. A polymerization inhibitor A may be added to the reaction system. The obtained product may be purified, as necessary, by known methods such as concentration, reprecipitation, and washing.

[0062] (Vinylphenyl Group-Containing Polymer) In some embodiments, the vinylphenyl compound includes a vinylphenyl group-containing polymer. The vinylphenyl compound may include a polymer having two vinylphenyl groups; or a polymer having three or more vinylphenyl groups. Examples of the vinylphenyl group-containing polymer include a polymer having a hydrocarbon chain skeleton and a vinylphenyl group; a polymer having a phenolic resin skeleton and a vinylphenyl group, and the like. Examples of polymers having a hydrocarbon chain skeleton include polyolefins, vinyl-based polymers, acrylic polymers, polydicyclopentadiene, and the like. Examples of phenolic resins include novolac-type phenolic resins, aralkyl-type phenolic resins, dicyclopentadiene-type phenolic resins, triphenylmethane-type phenolic resins, and resins of these phenolic resins that contain a naphthol structure instead of or in addition to the phenol structure.

[0063] From the viewpoints of moldability and handleability, the weight average molecular weight (Mw) of the vinylphenyl group-containing polymer is, for example, 300 to 50,000, 500 to 30,000, or 1,000 to 10,000. From the viewpoints of improving the fluidity of the curable composition and obtaining good moldability, the weight average molecular weight (Mw) may be 5,000 or less, or 2,500 or less.

[0064] In some embodiments, the vinyl phenyl compound comprises a polymer comprising a structure represented by formula (B1): (In the formula, X Ｂ１ represents an organic group, B represents a group containing a vinylphenyl group, R each independently represents a substituent, and m represents an integer of 0 to 10. * represents the bonding position to other atoms.

[0065] The organic group may be a group containing at least one carbon atom, for example, a group containing at least one selected from the group consisting of a saturated aliphatic hydrocarbon group, an unsaturated aliphatic hydrocarbon group, a saturated alicyclic hydrocarbon group, an unsaturated alicyclic hydrocarbon group, an aromatic hydrocarbon ring group, and an aromatic heterocyclic group. The organic group may or may not further contain a group containing a heteroatom.

[0066] Examples of the substituent represented by R include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, and n-pentyl. When the alkyl group has 3 or more carbon atoms, it may be a linear alkyl group. m represents, for example, an integer of 0 to 5, an integer of 0 to 2, or 0.

[0067] In some embodiments, the vinyl phenyl compound includes a polymer represented by the following formula (B2): When the vinyl phenyl compound includes a polymer represented by the following formula (B2), better heat resistance tends to be obtained. (In the formula, X Ｂ２ each independently represents a benzene ring or a naphthalene ring; each Y independently represents an organic group; B ｐ each independently represent a group represented by the following formula (Ph); each L independently represents a direct bond or a linking group; each R independently represents a substituent; each m independently represents an integer of 0 to 5; and n represents a number of 2 to 10. (In the formula, * represents the bonding position.)

[0068] The organic group may be a group containing at least one carbon atom, and examples thereof include alkylene groups such as a methylene group and an ethylene group; cycloalkylene groups such as tetrahydrodicyclopentadiene; arylalkylene groups such as a phenylmethylene group; and divalent organic groups containing an alkylene group and an arylene group.

[0069] From the viewpoint of obtaining a cured product having a low dielectric constant and a low dielectric loss tangent, the group represented by formula (Ph) may include a group represented by formula (p) above.

[0070] Examples of the linking group include an alkylene group (having, for example, 1 to 5 carbon atoms), an oxy group, a thio group, a sulfonyl group, a sulfinyl group, a carbonyl group, a carbonyloxy group, an imino group, and a divalent group formed by bonding two or more groups selected from these.

[0071] Examples of the substituent represented by R are as given in formula (B1). The substituent may be an alkyl group having 1 to 5 carbon atoms, or may be a methyl group. When the number of carbon atoms is 3 or more, the alkyl group may be a linear alkyl group. Each m independently represents, for example, an integer of 0 to 4, an integer of 0 to 2, or 0.

[0072] n is an average value in the polymer represented by formula (B2), and n is, for example, a number from 2 to 8, or a number from 3 to 5.

[0073] In some embodiments, the vinyl phenyl compound may comprise at least one selected from the group consisting of polymers represented by the formula: (In each formula, B ｐ each independently represents a group represented by the above formula (Ph), each L independently represents a direct bond or a linking group, and n represents a number from 2 to 10. The benzene ring and the naphthalene ring may each independently have a substituent at a substitutable position.

[0074] From the viewpoint of obtaining a cured product having a low dielectric constant and a low dielectric loss tangent, the group represented by formula (Ph) may include a group represented by formula (p) above.

[0075] Examples of the linking group are as given in formula (B2). The linking group may contain an oxy group from the viewpoint of obtaining good tracking resistance. The linking group may contain, for example, a methyleneoxy group. In this case, the polymer represented by the above formula may contain, for example, a methyleneoxy group. ｐ -CH ２ It includes a structure represented by -O-*.

[0076] When the benzene ring and the naphthalene ring in each formula have a substituent, examples of the substituent are as given for R in formula (B1). The substituent may be an alkyl group having 1 to 5 carbon atoms, or may be a methyl group. When the alkyl group has 3 or more carbon atoms, it may be a linear alkyl group. Alternatively, the benzene ring and the naphthalene ring in each formula may be unsubstituted, or may be a group selected from the group consisting of B ｐ It may not have any substituent other than -L-*.

[0077] n is an average value in the polymer represented by each formula, and n is, for example, a number from 2 to 8, or a number from 3 to 5.

[0078] When the vinylphenyl compound contains at least one selected from the group consisting of polymers represented by formula (B2-1) to formula (B2-11), excellent heat resistance tends to be easily obtained and the expansion amount tends to be small. When the vinylphenyl compound contains at least one selected from the group consisting of polymers represented by formula (B2-3) and polymers represented by formula (B2-7), low dielectric constants and dielectric loss tangents tend to be easily obtained. In particular, when the vinylphenyl compound contains a polymer represented by formula (B2-3), even lower dielectric constants and dielectric loss tangents tend to be obtained.

[0079] In some embodiments, the vinyl phenyl compound includes a polymer represented by formula (B3-3) below, a polymer represented by formula (B3-7) below, or both. (In the formula, B ｂ each independently represents a group represented by the following formula (Bz), and n represents a number of 3 to 5. (In the formula, B ｂ each independently represents a group represented by the following formula (Bz), and n represents a number of 3 to 5. (In the formula, * represents the bonding position.)

[0080] From the viewpoint of obtaining a cured product having a low dielectric constant and a low dielectric loss tangent, the group represented by formula (Bz) may include a group represented by formula (Bz) in which the bonding position of the vinyl group to the benzene ring is para to the bonding position of the methylene group to the benzene ring.

[0081] The method for synthesizing the vinylphenyl group-containing polymer is not particularly limited. For example, when the vinylphenyl group-containing polymer is a compound represented by formula (B2), a method of reacting a phenolic resin with a styrene having a halogenated methyl group in the presence of a basic compound can be mentioned. When synthesized by this method, the compound represented by formula (B2) has a methyleneoxy group as a linking group.

[0082] Examples of the styrene having a halogenated methyl group, the basic compound, and the phase transfer catalyst are as described above. The reaction can be carried out in a solvent. The reaction can be carried out under heating and stirring. A polymerization inhibitor A can be added to the reaction system. The obtained product can be purified, if necessary, by known methods such as concentration, reprecipitation, and washing.

[0083] Examples of phenolic resins include novolac-type phenolic resins, aralkyl-type phenolic resins, dicyclopentadiene-type phenolic resins, biphenyl-type phenolic resins, triphenylmethane-type phenolic resins, and resins containing a naphthol structure instead of or in addition to the phenol structure in these phenolic resins. Commercially available phenolic resins can be used.

[0084] The weight average molecular weight (Mw) of the phenolic resin is, for example, 300 to 30,000, 500 to 10,000, or 1,000 to 5,000 from the viewpoint of moldability and handleability of the curable composition. The number average molecular weight (Mn) of the phenolic resin is, for example, 200 to 10,000, 300 to 5,000, or 400 to 1,500 from the viewpoint of moldability and handleability. The hydroxyl group equivalent of the phenolic resin is, for example, 50 to 500 g / eq, 100 to 400 g / eq, or 150 to 300 g / eq from the viewpoint of heat resistance of the cured product. The hydroxyl group equivalent can be measured by a method in accordance with JIS K 0070:1992.

[0085] (Content) The curable composition may contain only one type of vinylphenyl compound, or may contain two or more types of vinylphenyl compounds. The content of the vinylphenyl compound is, for example, 10% by mass or more but less than 100% by mass, 15 to 98% by mass, or 20 to 95% by mass, based on the mass of the curable composition (excluding the mass of the filler if the curable composition contains a filler). The content of the vinylphenyl compound may be 75% by mass or less, 55% by mass or less, 35% by mass or less, or 30% by mass or less. When the content of the vinylphenyl compound is 10% by mass or more, the cured product tends to exhibit better heat resistance. From the viewpoint of obtaining particularly excellent heat resistance, the content of the vinylphenyl compound may be, for example, 70% by mass or more, 80% by mass or more, or 90% by mass or more.

[0086] When the vinylphenyl compound contains a vinylbenzyl compound, the content of the vinylbenzyl compound is, for example, 70% by mass or more, 80% by mass or more, or 90% by mass or more, based on the mass of the vinylphenyl compound. The upper limit of the content of the vinylbenzyl compound may be 100% by mass. When the vinylphenyl compound contains a vinylbenzyl ether compound, the content of the vinylbenzyl ether compound is, for example, 70% by mass or more, 80% by mass or more, or 90% by mass or more, based on the mass of the vinylphenyl compound. The upper limit of the content of the vinylbenzyl ether compound may be 100% by mass. When the curable composition contains a vinylbenzyl ether compound, tracking resistance tends to be improved.

[0087] When the vinylphenyl compound contains a vinylphenyl group-containing monomer and a vinylphenyl group-containing polymer, the content of the vinylphenyl group-containing monomer is, for example, 5 to 95 mass%, 50 to 90 mass%, or 70 to 88 mass%, based on the mass of the vinylphenyl compound. The content of the vinylphenyl group-containing polymer is, for example, 5 to 95 mass%, 10 to 50 mass%, or 12 to 30 mass%, based on the mass of the vinylphenyl compound.

[0088] When the curable composition contains a vinyl compound, the total content of the vinyl phenyl compound and the vinyl compound is, for example, 70% by mass or more but less than 100% by mass, 80 to 99% by mass, or 90 to 98% by mass, based on the mass of the curable composition (excluding the mass of the filler if the curable composition contains a filler). When the total content is 70% by mass or more, the cured product tends to exhibit better heat resistance. The total content may be 75 to 95% by mass, or 80 to 90% by mass.

[0089] When the curable composition contains a vinyl compound, the content of the vinylphenyl compound is, for example, 10 to 90% by mass, 15 to 80% by mass, or 20 to 70% by mass, based on the total mass of the vinylphenyl compound and the vinyl compound. When the content of the vinylphenyl compound is 10% by mass or more, the cured product tends to exhibit better heat resistance. From the viewpoint of obtaining a sufficient effect of the vinyl compound, the content of the vinylphenyl compound may be 90% by mass or less, or may be 60% by mass or less, 50% by mass or less, 45% by mass or less, or 30% by mass or less.

[0090] [Polymerization inhibitor] The curable composition contains a polymerization inhibitor. The polymerization inhibitor is added to the curable composition as at least the polymerization inhibitor B described above, and may further be added as at least one selected from the group consisting of the polymerization inhibitor A and polymerization inhibitor C described above. The polymerization inhibitor may be present in the curable composition in a state bonded to another compound such as a vinylphenyl compound, in a decomposed state, or the like. The polymerization inhibitor may include a stable radical compound that reacts with radicals generated in the polymerization reaction to form a bond, a compound that reacts with radicals generated in the polymerization reaction to generate stable radicals, or both of these compounds. The polymerization inhibitor may include a compound that can temporarily stop the polymerization reaction, a compound that can slow down the progress of the polymerization reaction, or both of these compounds.

[0091] When the curable composition contains a polymerization inhibitor, the progress of the reaction of the vinylphenyl compound can be suppressed, for example, during the preparation, storage, or molding of the curable composition, thereby preventing a decrease in fluidity. By using a curable composition with excellent fluidity, the moldability of the cured product can also be improved. Furthermore, when the curable composition contains a polymerization inhibitor, the cured product can be prevented from becoming non-uniform, and the strength of the cured product also tends to be improved.

[0092] Examples of polymerization inhibitors include TEMPO compounds, phenothiazine compounds, DPPH compounds, hindered amine compounds, phenol compounds, quinone compounds, and hydroquinone compounds. In some embodiments, from the viewpoint of the fluidity and storage stability of the curable composition, the polymerization inhibitor includes a nitrogen-containing compound. In some embodiments, from the viewpoint of the fluidity and storage stability of the curable composition, the polymerization inhibitor includes at least a TEMPO compound. The TEMPO compound can be used as a stable radical compound and as a compound that can temporarily stop the polymerization reaction. In some embodiments, from the viewpoint of the fluidity and storage stability of the curable composition, the polymerization inhibitor includes at least a phenothiazine compound. The phenothiazine compound can be used as a compound that generates stable radicals and as a compound that can slow down the progress of the polymerization reaction.

[0093] The TEMPO compound may be a compound containing a structure represented by the following formula (It): (In the formula, * indicates the bonding position to other atoms.)

[0094] In the structure represented by formula (It), the two * marks on at least one carbon atom included in the six-membered ring may be bonding positions to another atom. For example, the two * marks may be bonding positions to one oxygen atom. In this case, at least one of the carbon atoms included in the six-membered ring is bonded to the oxygen atom by a double bond, and the structure represented by formula (It) has an oxo group (O=).

[0095] Examples of TEMPO compounds include 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (OH-TEMPO), 4-oxo-2,2,6,6-tetramethylpiperidine 1-oxyl (4-Oxo-TEMPO), N-(3,3,5,5-tetramethyl-4-oxypiperidyl)pyrene-1-carboxamide (Pyrene-TEMPO), 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl radical (MeO-TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxybenzoate (BzO-TEMPO), 4-acetamido-2,2,6,6-tetramethyl-1-piperidinyloxy oxy (Ac-TEMPO), bis(2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl) sebacate (sebacic acid BisTEMPO), 4-(2-hydroxypropoxy-3-(2-hydroxyethoxy))-2,2,6,6-tetramethylpiperidin-1-ol, 4-(3-hydroxypropoxy-2-(2-hydroxyethoxy))-2,2,6,6-tetramethylpiperidin-1-ol, a mixture of 4-(2-hydroxypropoxy-3-(2-hydroxyethoxy))-2,2,6,6-tetramethylpiperidin-1-ol and 4-(3-hydroxypropoxy-2-(2-hydroxyethoxy))-2,2,6,6-tetramethylpiperidin-1-ol (EGG-TEMPO), and the like.

[0096] In some embodiments, the polymerization inhibitor includes at least one selected from the group consisting of a compound represented by the following formula (It-1) and a compound represented by the following formula (It-2): (In the formula, R ３ａ ~R ５ｂ each independently represents a hydrogen atom or a substituent. (In the formula, R ３ａ ~R ３ｄ and R ５ａ ~R ５ｄ each independently represents a hydrogen atom or a substituent, and L represents a linking group.

[0097] Examples of the substituent include an alkyl group, an alkoxy group, an alkylthio group, an alkylaryl group, an alkylheteroaryl group, an aryl group, an arylalkyl group, an aryloxy group, an arylthio group, a heteroaryl group, a heteroarylalkyl group, a heteroaryloxy group, a heteroarylthio group, an alkenyl group, an alkenyloxy group, an alkenylthio group, a hydroxy group, a mercapto group, a carboxy group, an alkylcarbonyl group, an alkylcarbonyloxy group, an alkyloxycarbonyl group, an amino group, an alkylamino group, a cyano group, an isocyanato group, a thiocyanato group, a halogen atom, a (meth)acryloyloxy group, a (meth)acryloylamino group, a maleimide group, and a group containing an epoxy group.

[0098] Examples of the linking group include an alkylene group, an arylene group, a heteroarylene group, an alkenylene group, an oxy group, a thio group, a carbonyl group, an oxycarbonyl group, an imino group, and a group containing two or more selected from these groups. The linking groups exemplified above may have a substituent, and examples of the substituent are as described above.

[0099] The linking group may be, for example, a group represented by the following formula (L1). (In the formula, each Y independently represents an oxy group (—O—), a carbonyl group (—C(═O)—), or a carbonyloxy group (—C(═O)—O—), and n is an integer of 1 to 20.)

[0100] The linking group may be, for example, a group represented by the following formula (L2). (In the formula, n is an integer from 1 to 20.)

[0101] In the compound represented by formula (It-1), R ３ａ ~R ５ｂ In the compound represented by formula (It-2), L may be a linking group containing a linear alkylene group, or may be a linking group containing a linear alkylene group having 4 to 20 carbon atoms, from the viewpoint of the fluidity of the curable composition.

[0102] The TEMPO compound is, for example, represented by formula (It-1), ３ａ , R３ｂ , and R ４ｂ ~R ５ｂ is a hydrogen atom, and R ４ａ is a hydrogen atom or a substituent. ４ａ may be a hydroxy group, an amino group, an alkoxy group (e.g., a methoxy group, an ethoxy group), a carboxy group, a (meth)acryloyloxy group, a maleimide group, or a group containing an oxetane group (e.g., a glycidyl ether group); or may be a hydroxy group. ３ａ ~R ５ｂ is a hydrogen atom, and L is a group represented by the above formula (L1) or (L2). In the above formulas (L1) and (L2), n may be 4 to 16, 6 to 12, or 8.

[0103] The molecular weight of the TEMPO compound is 156 or more, and from the viewpoint of flowability of the curable composition, it is, for example, 250 or more, 350 or more, or 450 or more. The molecular weight of the TEMPO compound is, for example, 800 or less, 700 or less, or 600 or less. The molecular weight of the TEMPO compound may be 156 to 800, 250 to 700, or 350 to 600.

[0104] The 5% weight loss temperature (Td5) of the TEMPO compound measured by thermogravimetry-differential thermal analysis (TG-DTA) is, from the viewpoint of the fluidity of the curable composition, for example, 105°C or higher, 115°C or higher, 150°C or higher, 180°C or higher, 200°C or higher, or 215°C or higher. The upper limit of Td5 is not particularly limited, but is, for example, 300°C or lower. The Td5 of the TEMPO compound may be 105 to 300°C, 150 to 300°C, or 200 to 300°C. In the present disclosure, the Td5 of the polymerization inhibitor can be measured using a TG-DTA device (for example, Hitachi High-Tech Science Corporation's "TG / DTA7300") under conditions of a nitrogen atmosphere and a heating rate of 5°C / min.

[0105] The phenothiazine compound may be a compound containing a structure represented by the following formula (Ip):

[0106] (In the formula, X represents a thio group (—S—) or a sulfinyl group (—S(═O)—), and * represents the bonding position to other atoms.)

[0107] Examples of the phenothiazine compound include phenothiazine, 2-methylphenothiazine, 2-ethylphenothiazine, 2-methoxyphenothiazine, 2-acetylphenothiazine, 2-methylthiophenothiazine, 2-ethylthiophenothiazine, 2-cyanophenothiazine, 2-chlorophenothiazine, 2-bromophenothiazine, 2-trifluoromethylphenothiazine, 3-methoxyphenothiazine, 10-methylphenothiazine, 10-ethylphenothiazine, 10-isopropylphenothiazine, 10-tert-butylphenothiazine, Examples of the phenothiazine include 10-acetylphenothiazine, 10-phenylphenothiazine, 2,8-dioctylphenothiazine, 2-cyano-8-methoxyphenothiazine, 3,7-dibutylphenothiazine, 3,7-dioctylphenothiazine, 3,7-dicumylphenothiazine, 3,7-dichloro-10-ethylphenothiazine, 3,7-dibromo-10-ethylphenothiazine, 3,7-bis(trifluoromethyl)-10-ethylphenothiazine, bis-(1-dimethylbenzyl)phenothiazine, and bis-(1-methylbenzyl)phenothiazine.

[0108] In some embodiments, the polymerization inhibitor comprises a compound represented by formula (Ip-1): (In the formula, R １ ~R ４ and R ６ ~R １０ each independently represents a hydrogen atom or a substituent.

[0109] Examples of the substituent include an alkyl group, an alkoxy group, an alkylthio group, an alkylaryl group, an alkylheteroaryl group, an aryl group, an arylalkyl group, an aryloxy group, an arylthio group, a heteroaryl group, a heteroarylalkyl group, a heteroaryloxy group, a heteroarylthio group, an alkenyl group, an alkenyloxy group, an alkenylthio group, a hydroxy group, a mercapto group, a carboxy group, an alkylcarbonyl group, an alkylcarbonyloxy group, an alkyloxycarbonyl group, an amino group, an alkylamino group, a cyano group, an isocyanato group, a thiocyanato group, a halogen atom, a (meth)acryloyloxy group, a (meth)acryloylamino group, a maleimide group, and a group containing an epoxy group.

[0110] R １ ~R ４ and R ６ ~R １０ may be a substituent from the viewpoint of flowability of the curable composition, and R １ ~R ４ and R ６ ~R １０ At least two selected from may be substituents.

[0111] The substituent may be a group containing carbon atoms, and from the viewpoint of the flowability of the curable composition, the number of carbon atoms in the substituent is, for example, 2 to 20, 4 to 16, or 6 to 12.

[0112] The phenothiazine compound is, for example, represented by formula (Ip-1), １ , R ２ , R ４ , R ５ , R ６ , and R ８ ~R １０ is a hydrogen atom, and R ３ and R ７ are each independently a hydrogen atom or a substituent. ３ and R ７may each independently be an alkyl group, an arylalkyl group, an alkylcarbonyl group, an alkenyl group, an amino group, or a carboxyalkylcarbonyl group; may be an alkyl group (such as a butyl group, a hexyl group, or an octyl group) or an arylalkyl group (such as a cumyl group).

[0113] The molecular weight of the phenothiazine compound is 199 or more, and from the viewpoint of the flowability of the curable composition, it is, for example, 250 or more, 300 or more, or 400 or more. The molecular weight of the phenothiazine compound is, for example, 800 or less, 700 or less, or 600 or less. The molecular weight of the phenothiazine compound may be 199 to 800, 250 to 700, or 400 to 600.

[0114] The 5% weight loss temperature (Td5) of the phenothiazine compound measured by thermogravimetry-differential thermal analysis (TG-DTA) is, from the viewpoint of the fluidity of the curable composition, for example, 170°C or higher, 180°C or higher, 200°C or higher, 220°C or higher, or 230°C or higher. The upper limit of Td5 is not particularly limited, but is, for example, 300°C or lower. The Td5 of the phenothiazine compound may be 170 to 300°C, 200 to 300°C, or 230 to 300°C.

[0115] An example of a DPPH compound is 2,2-diphenyl-1-picrylhydrazyl.

[0116] Examples of the hindered amine compound include 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethyl-1-hydroxypiperidine, 4-oxo-2,2,6,6-tetramethyl-1-oxypiperidine, and 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl.

[0117] Examples of phenolic compounds include p-methoxyphenol, pyrogallol, tert-butylcatechol, 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2,6-di-tert-butyl-4-methylphenol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), bis(2-hydroxy-3-t-butyl-5-ethylphenyl)methane, triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], pentaerythrityl tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, etc. In view of ease of handling or environmental considerations, the phenol compound may be a compound other than nitrophenol.

[0118] Examples of quinone compounds include 4-benzoquinone, tert-butylbenzoquinone, 2,6-di-tert-butyl-1,4-benzoquinone, 2,5-di-tert-butyl-1,4-benzoquinone, etc. Examples of hydroquinone compounds include hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, 2-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2,6-di-tert-butylhydroquinone, etc.

[0119] When the polymerization inhibitor includes at least one selected from the group consisting of a TEMPO compound and a phenothiazine compound, excellent fluidity tends to be obtained and the strength of the cured product tends to be high. In some embodiments, the polymerization inhibitor includes a TEMPO compound, and may include, for example, a TEMPO compound having a molecular weight of 156 to 800, 250 to 700, or 350 to 600; a TEMPO compound having a Td5 of 105 to 300°C, 150 to 300°C, or 200 to 300°C; a compound having a structure represented by formula (It); at least one selected from the group consisting of a compound represented by formula (It-1) and a compound represented by formula (It-2); or a compound represented by formula (It-2). In some embodiments, the polymerization inhibitor may include a phenothiazine compound, for example, a phenothiazine compound having a molecular weight of 199 to 800, 250 to 700, or 400 to 600; a phenothiazine compound having a Td5 of 170 to 300° C., 200 to 300° C., or 230 to 300° C.; a compound having a structure represented by formula (Ip); or a compound represented by formula (Ip-1). In some embodiments, the polymerization inhibitor may include at least one selected from the group consisting of phenothiazine, 3,7-dioctylphenothiazine, 3,7-dicumylphenothiazine, OH-TEMPO, and sebacate BisTEMPO.

[0120] The curable composition may contain only one type of polymerization inhibitor, or may contain two or more types of polymerization inhibitors. The content of the polymerization inhibitor is, for example, 0.05 to 7.0 mass%, 0.1 to 5.0 mass%, 0.5 to 4.0 mass%, or 1.0 to 3.0 mass%, based on the mass of the curable composition (excluding the mass of the filler if the curable composition contains a filler). When the content of the polymerization inhibitor is 0.1 mass% or more, the curable composition tends to exhibit better fluidity and the strength of the cured product tends to be higher. The content of the polymerization inhibitor may be 2.0 mass% or more. When the content of the polymerization inhibitor is 5.0 mass% or less, a decrease in curability tends to be suppressed. The content of the polymerization inhibitor may be 2.0 mass% or less.

[0121] When the polymerization inhibitor contains at least one compound selected from the group consisting of a TEMPO compound and a phenothiazine compound, the total content of the at least one compound is, for example, 70% by mass or more, 80% by mass or more, or 90% by mass or more, based on the mass of the polymerization inhibitor. The upper limit of the total content of the at least one compound may be 100% by mass. When the polymerization inhibitor contains the at least one compound, good fluidity tends to be obtained.

[0122] When the polymerization inhibitor contains a TEMPO compound, the content of the TEMPO compound is, for example, 70 mass% or more, 80 mass% or more, or 90 mass% or more, based on the mass of the polymerization inhibitor. The upper limit of the content of the TEMPO compound may be 100 mass%. When the polymerization inhibitor contains a TEMPO compound, good fluidity tends to be obtained.

[0123] When the polymerization inhibitor contains a phenothiazine compound, the content of the phenothiazine compound is, for example, 70 mass% or more, 80 mass% or more, or 90 mass% or more based on the mass of the polymerization inhibitor. The upper limit of the content of the phenothiazine compound may be 100 mass%. When the polymerization inhibitor contains a phenothiazine compound, good fluidity tends to be obtained.

[0124] When the polymerization inhibitor contains a TEMPO compound and a phenothiazine compound, the content of the TEMPO compound is, for example, 0.01% by mass or more but less than 100.0% by mass, 0.1 to 99.9% by mass, or 1.0 to 99.0% by mass, based on the mass of the polymerization inhibitor. The content of the TEMPO compound may be 50.0% by mass or more, 70.0% by mass or more, or 80.0% by mass or more. The content of the phenothiazine compound is, for example, 0.01% by mass or more but less than 100.0% by mass, 0.1 to 99.9% by mass, or 1.0 to 99.0% by mass, based on the mass of the polymerization inhibitor. The content of the phenothiazine compound may be 50.0% by mass or less, 30.0% by mass or less, or 20.0% by mass or less.

[0125] When the curable composition contains a TEMPO compound, the content of the TEMPO compound is, for example, 0.1 to 5.0 mass%, 0.5 to 4.0 mass%, or 1.0 to 3.0 mass%, based on the mass of the curable composition (however, when the curable composition contains a filler, the mass of the filler is excluded). When the content of the TEMPO compound is 0.1 mass% or more, the curable composition tends to exhibit better fluidity and the strength of the cured product also tends to be higher.

[0126] When the curable composition contains a phenothiazine compound, the content of the phenothiazine compound is, for example, 0.01 to 5.0 mass%, 0.05 to 4.0 mass%, or 0.1 to 3.0 mass%, based on the mass of the curable composition (however, when the curable composition contains a filler, the mass of the filler is excluded). When the content of the phenothiazine compound is 0.1 mass% or more, the curable composition tends to exhibit better fluidity and the strength of the cured product also tends to be higher.

[0127] [Compound Having a Vinyl Bond] The curable composition may further contain a vinyl compound. The vinyl compound is a compound having at least one vinyl bond (excluding compounds corresponding to vinylphenyl compounds and compounds corresponding to polymerization inhibitors). The vinyl bond may be a radically polymerizable carbon-carbon unsaturated bond. Examples of vinyl compounds include those in which the vinyl bond is CH ２Examples of suitable vinyl compounds include a compound having a vinyl bond as a monovalent group represented by =CH-*, a compound having a vinyl bond as a divalent group represented by *-CH=CH-*, and a compound having both the monovalent group and the divalent group. The vinyl compound has, for example, 1 to 20, 1 to 15, or 1 to 10 vinyl bonds. The vinyl compound may consist of one type of vinyl compound or may contain two or more types of vinyl compounds. The vinyl compound does not have a vinylphenyl group. When the curable composition contains a vinyl compound, the curability is good, and a cured product having a high glass transition temperature and excellent heat resistance can be obtained.

[0128] The vinyl compound may be a monomer or polymer capable of radical polymerization. The vinyl compound includes, for example, a monomer having a vinyl bond. In the present disclosure, a monomer having a vinyl bond may be referred to as a "vinyl bond-containing monomer." The vinyl compound includes, for example, a polymer having a vinyl bond. In the present disclosure, a polymer having a vinyl bond may be referred to as a "vinyl bond-containing polymer."

[0129] In some embodiments, the vinyl compound includes a compound having two vinyl bonds. The compound having two vinyl bonds may be a monomer or a polymer. In some embodiments, the vinyl compound includes a compound having three or more vinyl bonds. The compound having three or more vinyl bonds may be a monomer or a polymer.

[0130] Examples of vinyl bond-containing monomers include olefin compounds such as ethylene, propylene, butadiene, isoprene, dimethylbutadiene, chloroprene, and 1,3-pentadiene; (meth)acrylic acid ester compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tetra(meth)acrylate, and bisphenol A diglycidyl ether di(meth)acrylate; and carboxyl group-containing vinyl compounds such as (meth)acrylic acid, itaconic acid, maleic acid, and fumaric acid. halogen-containing vinyl compounds such as vinyl chloride and vinylidene chloride; nitrile group-containing vinyl compounds such as acrylonitrile and methacrylonitrile; amide group-containing vinyl compounds such as acrylamide, methacrylamide, N-methylolacrylamide and N-methylolmethacrylamide; maleimide compounds such as maleimide, N-phenylmaleimide and 4,4'-diphenylmethane bismaleimide; and nitrogen-containing vinyl compounds other than those mentioned above such as N-vinylpyrrolidone, 1-vinylimidazole and vinylcarbazole.

[0131] Examples of the vinyl bond-containing polymer include polymers having a hydrocarbon chain skeleton and a vinyl bond, polymers having a phenolic resin skeleton and a vinyl bond, polyamides, polyamideimides, or polyimides having a vinyl bond, etc. Examples of polymers having a hydrocarbon chain skeleton and phenolic resins are the same as those listed for the vinylphenyl group-containing polymer.

[0132] (Maleimide Compound) In some embodiments, the vinyl compound includes a compound having a maleimide group. In the present disclosure, a compound having a maleimide group may be referred to as a "maleimide compound." A maleimide compound is a compound having at least one maleimide group. The maleimide compound has, for example, 1 to 20, 1 to 15, or 1 to 10 maleimide groups. The maleimide compound may consist of one type of maleimide compound or may include two or more types of maleimide compounds. When the curable composition includes a maleimide compound, the curability is improved and a cured product with a small amount of expansion can be obtained.

[0133] The maleimide group can be represented by the following formula: * indicates the bonding position to other atoms.

[0134] In some embodiments, the maleimide compound includes a compound having two maleimide groups, which may be referred to as a "bismaleimide" in the present disclosure.

[0135] In some embodiments, the vinyl compound includes a compound represented by formula (m1): (In the formula, X ｍ represents an organic group, and M represents a maleimide group.

[0136] The organic group may be a group containing at least one carbon atom, for example, a group containing at least one selected from the group consisting of saturated aliphatic hydrocarbon groups, unsaturated aliphatic hydrocarbon groups, saturated alicyclic hydrocarbon groups, unsaturated alicyclic hydrocarbon groups, aromatic hydrocarbon ring groups, and aromatic heterocyclic groups. The organic group may or may not further contain a group containing a heteroatom. From the viewpoint of improving the heat resistance of the cured product, the organic group is preferably a group containing at least one selected from the group consisting of aromatic hydrocarbon ring groups and aromatic heterocyclic groups.

[0137] In some embodiments, the vinyl compound may include at least one selected from the group consisting of compounds represented by the following formula: (In each formula, M represents a maleimide group, L ２ represents a direct bond or a linking group, Rｈａ each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and n represents an integer of 1 to 8. The benzene ring may each independently have a substituent at a substitutable position.

[0138] L ２ Examples of the linking group represented by the formula (m-2L) include an alkylene group (having, for example, 1 to 5, 2 to 5, or 3 to 5 carbon atoms), an oxy group, a thio group, a sulfonyl group, a sulfinyl group, a carbonyl group, a carbonyloxy group, an imino group, and a group represented by the following formula (m-2L). Examples of the alkylene group having 1 to 5 carbon atoms include linear alkylene groups such as a methylene group, a 1,2-dimethylene group, a 1,3-trimethylene group, a 1,4-tetramethylene group, and a 1,5-pentamethylene group, and branched alkylene groups such as an isopropylene group, an isobutylene group, and a t-butylene group. (In the formula, L ２Ｌ represents a direct bond or a linking group. Each benzene ring may independently have a substituent at a substitutable position. * represents a bonding position.

[0139] L ２Ｌ Examples of the linking group represented by the formula (I) include an alkylene group (having, for example, 1 to 5 carbon atoms), an oxy group, a thio group, a sulfonyl group, a sulfinyl group, a carbonyl group, a carbonyloxy group, and an imino group. Examples of alkylene groups having 1 to 5 carbon atoms include L ２ As mentioned above.

[0140] In the above formulas (m-1), (m-2), and (m-2L), the benzene rings may each independently be unsubstituted or may have a substituent at a substitutable position. Examples of the substituent include alkyl groups having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, and an n-pentyl group. The substituent may be an alkyl group having 1 to 3 carbon atoms, or may be a methyl group.

[0141] In the above formula (m-3), R ｈａ Examples of the alkyl group having 1 to 5 carbon atoms represented by the formula (I) are as described above. n represents, for example, an integer of 1 to 6, an integer of 1 to 3, or an integer of 4 to 6.

[0142] When the vinyl compound contains at least one selected from the group consisting of compounds represented by formula (m-1) and compounds represented by formula (m-2), excellent heat resistance tends to be easily obtained. ２ The vinyl compound may include a compound represented by formula (m-3) in which n is 4 to 8.

[0143] In some embodiments, the vinyl compound includes a polymer having a maleimide group. In the present disclosure, a polymer having a maleimide group may be referred to as a "maleimide group-containing polymer." The vinyl compound may include a polymer having two maleimide groups; or a polymer having three or more maleimide groups. Examples of maleimide compounds include polymers having a hydrocarbon chain skeleton and a maleimide group; polymers having a phenolic resin skeleton and a maleimide group; and polyamides, polyamideimides, or polyimides having maleimide groups. Examples of polymers having a hydrocarbon chain skeleton and phenolic resins are the same as those listed for the vinylphenyl group-containing polymer.

[0144] In some embodiments, the maleimide compound comprises a polymer represented by formula (M1): (In the formula, X Ｍ each independently represents a benzene ring or a naphthalene ring; each independently represents an organic group; M represents a maleimide group; each independently represents a direct bond or a linking group; each independently represents a substituent; each independently represents an integer of 0 to 5; and n represents a number of 2 to 10.

[0145] The organic group may be a group containing at least one carbon atom, and examples thereof include alkylene groups such as a methylene group and an ethylene group; cycloalkylene groups such as tetrahydrodicyclopentadiene; arylalkylene groups such as a phenylmethylene group; and divalent organic groups containing an alkylene group and an arylene group.

[0146] Examples of the linking group include an alkylene group (having, for example, 1 to 5 carbon atoms), an oxy group, a thio group, a sulfonyl group, a sulfinyl group, a carbonyl group, a carbonyloxy group, an imino group, and a divalent group formed by bonding two or more groups selected from these.

[0147] Examples of the substituent represented by R include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, and n-pentyl. The substituent may be an alkyl group having 1 to 3 carbon atoms, or a methyl group. Each m independently represents, for example, an integer of 0 to 4, an integer of 0 to 2, or 0.

[0148] n is an average value in the polymer represented by formula (M1), and n is, for example, a number from 2 to 8, or a number from 3 to 5.

[0149] In some embodiments, the maleimide compound may include at least one selected from the group consisting of polymers represented by the following formula: When the vinyl compound includes at least one selected from the group consisting of polymers represented by the following formula: (In each formula, M represents a maleimide group, each L independently represents a direct bond or a linking group, and n represents a number from 2 to 10. The benzene ring and the naphthalene ring may each independently have a substituent at a substitutable position.)

[0150] When the benzene ring and the naphthalene ring in each formula have a substituent, examples of the substituent are as given for R in formula (M1). The substituent may be an alkyl group having 1 to 3 carbon atoms or a methyl group. Alternatively, the benzene ring and the naphthalene ring in each formula may be unsubstituted or may not have a substituent other than M-L-*.

[0151] n is an average value in the polymer represented by each formula, and n is, for example, a number from 2 to 8, or a number from 3 to 5.

[0152] Specific examples of the maleimide compound include novolak-type maleimide compounds such as bis(4-maleimidophenyl)methane, polyphenylmethane maleimide, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, m-phenylene bismaleimide, 2,2-bis(4-(4-maleimidophenoxy)phenyl)propane, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, and polyphenylmethane maleimide, and aralkyl-type maleimide compounds. The maleimide compound includes, for example, at least one selected from the group consisting of 2,2-bis(4-(4-maleimidophenoxy)phenyl)propane, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane, and polyphenylmethanemaleimide.

[0153] Commercially available maleimide compounds can be used. Examples of commercially available maleimide compounds include "BMI-80" (2,2-bis[4-(4-maleimidophenoxy)phenyl]propane), "BMI-1000, BMI-1000H, BMI-1100, BMI-1100H" (all 4,4'-diphenylmethane bismaleimide), and "BMI-2000, BMI-2300" (all phenylmethane bismaleimide), manufactured by Daiwa Chemical Industry Co., Ltd. maleimide), "BMI-3000, BMI-3000H" (both m-phenylene bismaleimide), "BMI-4000" (bisphenol A diphenyl ether bismaleimide), "BMI-5100" (3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide), "BMI-7000, BMI-7000H" (both 4-methyl-1,3-phenylene bismaleimide), "BMI-TMH" (1,6'-bismaleimide-(2,2,4-trimethyl)hexane); Designer Molecules Inc. Examples of such a polymer include "BMI-2500, BMI-2560, BMI-3000, BMI-5000, BMI-6100" manufactured by Isuzu Corporation; "NE-X470S" manufactured by DIC Corporation; and "MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd.

[0154] (Content) When the curable composition contains a vinyl compound, the curable composition may contain only one type of vinyl compound, or may contain two or more types of vinyl compounds. When the curable composition contains a vinyl compound, the content of the vinyl compound is, for example, 10 to 90 mass%, 20 to 80 mass%, or 30 to 75 mass%, based on the mass of the curable composition (however, when the curable composition contains a filler, the mass of the filler is excluded). When the content is 10 mass% or more, a sufficient effect of the vinyl compound tends to be easily obtained. The content of the vinyl compound may be 40 mass% or more, 50 mass% or more, 55 mass% or more, 60 mass% or more, or 65 mass% or more. When the content of the vinyl compound is 90 mass% or less, the effect of improving heat resistance due to the vinyl phenyl compound tends to be easily obtained.

[0155] When the curable composition contains a vinyl compound, the content of the vinyl compound is, for example, 10 to 90% by mass, 20 to 85% by mass, or 30 to 80% by mass, based on the total mass of the vinyl phenyl compound and the vinyl compound. When the content is 10% by mass or more, a sufficient effect of the vinyl compound tends to be easily obtained. The content of the vinyl compound may be 40% by mass or more, 50% by mass or more, 60% by mass, or 70% by mass or more. When the content of the vinyl compound is 90% by mass or less, the effect of improving heat resistance due to the vinyl phenyl compound tends to be easily obtained.

[0156] When the vinyl compound contains a maleimide compound, the content of the maleimide compound is, for example, 70% by mass or more, 80% by mass or more, or 90% by mass or more based on the mass of the vinyl compound. The upper limit of the content of the maleimide compound may be 100% by mass.

[0157] When the curable composition contains a maleimide compound, the curable composition may contain only one type of maleimide compound, or may contain two or more types of maleimide compounds. When the curable composition contains a maleimide compound, the content of the maleimide compound is, for example, 10 to 90 mass%, 20 to 80 mass%, or 30 to 75 mass%, based on the mass of the curable composition (excluding the mass of the filler if the curable composition contains a filler). When the content of the maleimide compound is 10 mass% or more, the cured product tends to exhibit a smaller amount of expansion. In particular, from the viewpoint of reducing the amount of expansion, the content of the maleimide compound may be 40 mass% or more, 50 mass% or more, 55 mass% or more, or 60 mass% or more. When the content of the maleimide compound is 90 mass% or less, the effect of improving heat resistance due to the vinylphenyl compound tends to be easily obtained.

[0158] When the curable composition contains a maleimide compound, the content of the maleimide compound is, for example, 10 to 90% by mass, 20 to 85% by mass, or 30 to 80% by mass, based on the total mass of the vinylphenyl compound and the maleimide compound. When the content of the maleimide compound is 10% by mass or more, the cured product tends to exhibit a smaller amount of expansion. In particular, from the viewpoint of reducing the amount of expansion, the content of the maleimide compound may be 40% by mass or more, 50% by mass or more, 60% by mass, or 70% by mass or more. When the content of the maleimide compound is 90% by mass or less, the effect of improving heat resistance due to the vinylphenyl compound tends to be easily obtained.

[0159] When the curable composition contains a maleimide compound, from the viewpoints of dielectric properties, curability, moldability, and conductor adhesion, the ratio of the content of vinylphenyl groups to the content of maleimide groups in the curable composition (vinylphenyl groups (mol) / maleimide groups (mol)) may be, for example, 0.05 to 5.0, 0.20 to 3.0, or 0.30 to 1.0.

[0160] [Optional Components] The curable composition may contain optional components. Examples of optional components include various additives such as the above-mentioned vinyl compounds, radical polymerization initiators, fillers, coupling agents, mold release agents, colorants, ion exchangers, flame retardants, and stress relaxation agents. The curable composition may contain various additives as needed in addition to the following examples.

[0161] (Radical Polymerization Initiator) The curable composition may contain a radical polymerization initiator. When the curable composition is used for molding by heating, the radical polymerization initiator may be a thermal radical polymerization initiator that generates free radicals by heating. The thermal radical polymerization initiator may be, for example, an organic peroxide such as peroxyketal or dialkyl peroxide, or an azo compound such as azobisbutyronitrile or azobispropionitrile.

[0162] Examples of organic peroxides include 1,1,3,3-tetramethylbutylperoxyneodecanoate, di(4-t-butylcyclohexyl)peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, cumylperoxyneodecanoate, dilauroyl peroxide, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, and t-butylperoxyneodecanoate. Pivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyneoheptanoate, t-amylperoxy-2-ethylhexanoate, di-t-butylperoxyhexahydroterephthalate, t-amylperoxy-3,5, 5-trimethylhexanoate, 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate, t-amylperoxyneodecanoate, di(3-methylbenzoyl) peroxide, dibenzoyl peroxide, di(4-methylbenzoyl) peroxide, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2, Examples of such peroxyalkylene compounds include 5-dimethyl-2,5-di(3-methylbenzoylperoxy)hexane, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butyl peroxybenzoate, dibutyl peroxytrimethyl adipate, t-amyl peroxy normal octoate, t-amyl peroxy isononanoate, and t-amyl peroxybenzoate.

[0163] Examples of azo compounds include 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-azobis(1-acetoxy-1-phenylethane), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 4,4'-azobis(4-cyanovaleric acid), and 1,1'-azobis(1-cyclohexanecarbonitrile).

[0164] When the curable composition contains a radical polymerization initiator, the curable composition may contain only one type of radical polymerization initiator, or may contain two or more types of radical polymerization initiators. When the curable composition contains a radical polymerization initiator, the content of the radical polymerization initiator may be 0.1 to 5 mass%, or 0.2 to 3 mass%, based on the total mass of the vinylphenyl compound and the vinyl compound contained as needed (when the curable composition does not contain a vinyl compound, the mass of the vinylphenyl compound is omitted; the same applies below). When the curable composition does not contain a radical polymerization initiator, the content of the radical polymerization initiator may be 0.0 mass%. For example, when the curable composition does not contain a vinyl compound, the curable composition may contain a radical polymerization initiator. For example, when the curable composition contains a vinyl compound, the curable composition does not need to contain a radical polymerization initiator.

[0165] (Filler) The curable composition may contain a filler. When the curable composition contains a filler, the properties of the cured product, such as the thermal expansion coefficient, thermal conductivity, and elastic modulus, tend to be improved. Examples of fillers include inorganic fillers and organic fillers. In some embodiments, the curable composition contains an inorganic filler.

[0166] The inorganic filler may have an average particle size of 5 μm or more. From the viewpoint of improving the filling property of the curable composition, the inorganic filler may have an average particle size of 100 μm or less. The inorganic filler may have an average particle size of, for example, 5 to 100 μm, 8 to 50 μm, or 10 to 30 μm.

[0167] The average particle size of the inorganic filler can be determined by the following method. A thin section sample is prepared from the curable composition or a cured product of the curable composition. 100 particles of the inorganic filler are randomly selected from an image of the thin section sample taken with a scanning electron microscope. The major axis of each particle is measured, and the arithmetic mean value is used as the average particle size of the inorganic filler.

[0168] The type of inorganic filler is not particularly limited. Examples include silica such as fused silica and crystalline silica; alumina, zirconia, titania, glass, talc, clay, and mica. The inorganic filler may be an inorganic filler having a flame retardant effect. Examples of inorganic fillers having a flame retardant effect include aluminum hydroxide; magnesium hydroxide; composite metal hydroxides such as a composite hydroxide of magnesium and zinc; and zinc borate.

[0169] The inorganic filler may contain silica to reduce the linear expansion coefficient, or alumina to improve thermal conductivity. The inorganic filler may be in the form of powder, spherical beads formed from powder, or fibers.

[0170] When the curable composition contains a filler, the curable composition may contain only one type of filler, or may contain two or more types of fillers. When the curable composition contains a filler, the filler content is, for example, 100 to 2,000 mass%, 250 to 1,500 mass%, or 350 to 700 mass%, based on the mass of the curable composition (excluding the mass of the filler). When the filler content is 100 mass% or more, the properties of the cured product, such as the thermal expansion coefficient, thermal conductivity, and elastic modulus, tend to be further improved. When the filler content is 2,000 mass% or less, the increase in viscosity of the curable composition is suppressed, and the fluidity tends to be further improved, resulting in better moldability. When the curable composition contains a filler, the filler content (excluding carbon black) is, for example, 50 to 90 volume%, 55 to 85 volume%, or 60 to 80 volume%, based on the volume of the curable composition. When the filler content is 50% by volume or more, the properties of the cured product, such as the thermal expansion coefficient, thermal conductivity, and elastic modulus, tend to be further improved.When the filler content is 90% by volume or less, an increase in the viscosity of the curable composition is suppressed, and the flowability is further improved, tending to result in better moldability.

[0171] (Coupling Agent) The curable composition may contain a coupling agent. When the curable composition contains a coupling agent, the adhesiveness of the cured product, or the adhesiveness between the resin component (vinylphenyl compound, vinyl compound included as needed, etc.) and the inorganic filler tends to be improved. Examples of coupling agents include silane coupling agents, titanate coupling agents, aluminum chelate coupling agents, and aluminum / zirconium coupling agents. Examples of silane coupling agents include epoxy silane coupling agents, mercapto silane coupling agents, amino silane coupling agents, alkyl silane coupling agents, ureido silane coupling agents, vinyl silane coupling agents, (meth)acrylic silane coupling agents, and disilazane coupling agents. In the present disclosure, when the curable composition contains a coupling agent, coupling agents having a vinylphenyl group are excluded from the scope of the above-mentioned vinylphenyl compound, and coupling agents having a vinyl group are excluded from the scope of the above-mentioned vinyl compound. In other words, vinylphenyl compounds and vinyl compounds are compounds other than compounds that fall under the category of coupling agents. When the curable composition contains a mercapto-based silane coupling agent or an amino-based silane coupling agent, the adhesiveness of the cured product tends to be improved.When the curable composition contains a vinyl-based silane coupling agent or a (meth)acrylic silane coupling agent, the moldability and the strength of the cured product tend to be improved.

[0172] Examples of silane coupling agents include vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and N-phenyl-3-aminopropyl Trimethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropyltriethoxysilane, γ-(N,N-dimethyl)aminopropyltrimethoxysilane, γ-(N,N-diethyl)aminopropyltrimethoxysilane, γ-(N,N-dibutyl)aminopropyltrimethoxysilane, γ-(N-methyl)anilinopropyltrimethoxysilane, γ-(N-ethyl)anilinopropyltrimethoxysilane γ-(N,N-dimethyl)aminopropyltrimethoxysilane, γ-(N,N-diethyl)aminopropyltriethoxysilane, γ-(N,N-dibutyl)aminopropyltriethoxysilane, γ-(N-methyl)anilinopropyltriethoxysilane, γ-(N-ethyl)anilinopropyltriethoxysilane, γ-(N,N-dimethyl)aminopropylmethyldimethoxysilane, γ-(N,N-diethyl)aminopropylmethyldimethoxysilane, γ-(N,N-dibutyl)aminopropyl Examples of such silane include methyldimethoxysilane, γ-(N-methyl)anilinopropylmethyldimethoxysilane, γ-(N-ethyl)anilinopropylmethyldimethoxysilane, N-(trimethoxysilylpropyl)ethylenediamine, N-(dimethoxymethylsilylisopropyl)ethylenediamine, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, vinyltrimethoxysilane, and γ-mercaptopropylmethyldimethoxysilane.

[0173] When the curable composition contains a coupling agent, the curable composition may contain only one type of coupling agent, or may contain two or more types of coupling agents. When the curable composition contains an inorganic filler and a coupling agent, the content of the coupling agent is, for example, 0.01 to 10 mass%, 0.05 to 5 mass%, or 0.1 to 2 mass%, based on the mass of the inorganic filler. When the content of the coupling agent is 0.1 mass% or more, the adhesiveness of the cured product tends to be improved. When the content of the coupling agent is 2 mass% or less, the moldability of the cured product tends to be improved.

[0174] (Mold release agent) The curable composition may contain a mold release agent. When the curable composition contains a mold release agent, good mold releasability from the mold during molding is easily obtained. Examples of the mold release agent include known mold release agents such as carnauba wax; higher fatty acids such as montanic acid and stearic acid, higher fatty acid metal salts; ester waxes such as montanic acid esters; and polyolefin waxes such as oxidized polyethylene and non-oxidized polyethylene.

[0175] When the curable composition contains a release agent, the curable composition may contain only one type of release agent, or may contain two or more types of release agents. When the curable composition contains a release agent, the content of the release agent is, for example, 0.01 to 10 mass%, 0.05 to 5 mass%, or 0.1 to 2 mass%, based on the total mass of the vinyl phenyl compound and the vinyl compound contained as needed. When the content of the release agent is 0.01 mass% or more, sufficient release properties tend to be obtained. When the content of the release agent is 10 mass% or less, better adhesion tends to be obtained.

[0176] (Colorant) The curable composition may contain a colorant. Examples of the colorant include known colorants such as carbon black, organic dyes, organic pigments, titanium oxide, red lead, and red iron oxide. The content of the colorant can be appropriately selected depending on the purpose, etc. The colorant may also function as a filler.

[0177] When the curable composition contains a colorant, the curable composition may contain only one colorant or two or more colorants. When the curable composition contains a colorant, the content of the colorant is, for example, 0.01 to 10 mass % or 0.1 to 5 mass % based on the total mass of the vinyl phenyl compound and the vinyl compound that is optionally contained.

[0178] (Ion Exchanger) The curable composition may contain an ion exchanger. When the curable composition contains an ion exchanger, the moisture resistance and high-temperature storage characteristics of the electronic component device tend to be improved. Examples of the ion exchanger include hydrotalcite compounds; and hydrous oxides of at least one element selected from the group consisting of magnesium, aluminum, titanium, zirconium, and bismuth. The ion exchanger may also function as a filler. The curable composition may contain only one type of ion exchanger, or two or more types of ion exchangers.

[0179] (Flame Retardant) The curable composition may contain a flame retardant. Examples of the flame retardant include organic or inorganic compounds containing a halogen atom, an antimony atom, a nitrogen atom, or a phosphorus atom, and metal hydroxides. The curable composition may contain only one type of flame retardant, or may contain two or more types of flame retardants.

[0180] (Stress Relaxant) The curable composition may contain a stress relaxation agent. When the curable composition contains a stress relaxation agent, warpage and cracking of electronic component devices tend to be reduced. Examples of stress relaxation agents include silicone oil; thermoplastic elastomers such as silicone, styrene, olefin, urethane, polyester, polyether, polyamide, and polybutadiene elastomers; rubber particles such as NR (natural rubber), NBR (acrylonitrile-butadiene rubber), acrylic rubber, urethane rubber, and silicone powder; and rubber particles having a core-shell structure such as methyl methacrylate-styrene-butadiene copolymer (MBS), methyl methacrylate-silicone copolymer, and methyl methacrylate-butyl acrylate copolymer (excluding compounds corresponding to vinyl phenyl compounds or vinyl compounds). When the curable composition contains a stress relaxation agent, the curable composition may contain only one type of stress relaxation agent, or may contain two or more types of stress relaxation agents. Commercially available flexibility-imparting agents can be used as the stress relaxation agent.

[0181] (Solvent) The curable composition may contain a solvent. Examples of the solvent include alcohol-based solvents such as butyl carbitol acetate, methyl alcohol, ethyl alcohol, propyl alcohol, and butyl alcohol, ketone-based solvents such as acetone and methyl ethyl ketone, glycol ether-based solvents such as ethylene glycol ethyl ether, ethylene glycol methyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol methyl ether acetate, lactone-based solvents such as γ-butyrolactone, δ-valerolactone, and ε-caprolactone, amide-based solvents such as dimethylacetamide and dimethylformamide, and aromatic solvents such as toluene and xylene.

[0182] When the curable composition contains a solvent, the curable composition may contain only one type of solvent, or may contain two or more types of solvents. The curable composition may not contain a solvent. The solvent content can be adjusted depending on the application of the curable composition. The solvent content may be, for example, 0.00 to 100% by mass based on the solid content mass of the curable composition (excluding the mass of the filler). When the curable composition is a solid such as a powder, granule, or tablet, the solvent content may be, for example, 5.00% by mass or less, 1.00% by mass or less, 0.50% by mass or less, or 0.10% by mass or less.

[0183] [Applications] The curable composition can be cured by applying heat, light, or both. The curable composition may be a thermosetting composition. The cured product obtained using the curable composition has good heat resistance and can be used for members, parts, or products that require heat resistance. Examples of members, parts, or products that require heat resistance include adhesive layers, protective layers, sealing materials, circuit boards, electronic components, semiconductor devices, semiconductor modules, cooking utensils, image display devices, electrical components, automotive parts, mechanical parts, industrial products, and home appliances. The adhesive layers, protective layers, and sealing materials may be used for electronic components, semiconductor devices, or semiconductor modules, for example. The curable composition has good fluidity and can be used to produce cured products in various shapes. Examples of the shape of the cured product include films, thin films, and molded products.

[0184] <Encapsulant> In some embodiments, the encapsulant includes a cured product obtained using the curable composition of the above embodiment. The encapsulant can be used to encapsulate electronic components, electronic component devices, semiconductor elements, semiconductor devices, etc. The cured product can be produced, for example, by molding the curable composition and heating the resulting molded product. Heating conditions are, for example, 150 to 180°C for 2 to 16 hours.

[0185] <Electronic Component Device> In some embodiments, an electronic component device includes the encapsulant of the above embodiment. The electronic component device includes, for example, an electronic component and the encapsulant of the above embodiment that encapsulates at least a portion of the electronic component. The electronic component device may be, for example, an electronic component module that includes a plurality of electronic components and electronic component devices and the encapsulant of the above embodiment that encapsulates at least a portion of the plurality of electronic components.

[0186] Examples of electronic components include active elements or components such as diodes, transistors, integrated circuits, and relays; passive elements or components such as resistors, capacitors, and coils; connectors, support members, terminals, and switches. Examples of electronic component devices include electronic component devices having the electronic components; and modules having one or both of the electronic components and the electronic component devices. The electronic component device may have a support member. Examples of support members include lead frames, pre-wired tape carriers, wiring boards, glass, silicon wafers, and organic substrates.

[0187] The semiconductor device may be, for example, a semiconductor module including a plurality of semiconductor elements and semiconductor devices, and the sealing material of the above embodiment that seals at least a portion of the plurality of semiconductor elements.

[0188] Examples of semiconductor elements include diodes, transistors, thyristors, power semiconductor elements, photoelectric conversion elements, sensors, ICs (integrated circuits), memories, etc. The semiconductor device may be in a known package form, such as an insertion mount package or a surface mount package. Examples of surface mount packages include a lead frame type and a bump type. Specific examples include resin-sealed integrated circuits (ICs) such as SIP (Single Inline Package), DIP (Dual Inline Package), PGA (Pin Grid Array), PLCC (Plastic Leaded Chip Carrier), QFP (Quad Flat Package), SOP (Small Outline Package), SOJ (Small Outline J-lead package), TSOP (Thin Small Outline Package), and TQFP (Thin Quad Flat Package). Examples of the semiconductor device include a PCB (Chip Size Package), a TCP (Tape Carrier Package), a COB (Chip On Board), a BGA (Ball Grid Array), and a CSP (Chip Size Package). Specific examples include a MCP (Multi-Chip Package) such as a MCM (Multi-Chip Module), and a hybrid IC.

[0189] A resin-encapsulated IC, for example, has a structure in which a semiconductor element is fixed on a lead frame, and terminal portions of the semiconductor element, such as bonding pads, are connected to lead portions via wire bonding, bumps, or the like, and then encapsulated using a curable composition by transfer molding or the like. A TCP, for example, has a structure in which a semiconductor element connected to a tape carrier via bumps is encapsulated with a curable composition. A COB, for example, has a structure in which a semiconductor element connected to wiring formed on a support member via wire bonding, flip-chip bonding, solder, or the like, is encapsulated with a curable composition. BGA, CSP, and MCP, for example, have a structure in which a semiconductor element is mounted on the surface of a support member having terminals for wiring board connection formed on the back surface, and the semiconductor element is connected to the wiring formed on the support member via bumps or wire bonding, and then the semiconductor element is encapsulated with a curable composition. An MCM, for example, has a structure in which multiple semiconductor elements connected to wiring formed on a support member via wire bonding, flip-chip bonding, solder, or the like, are encapsulated with a curable composition.

[0190] For example, a method for manufacturing an electronic component device includes placing an electronic component on a support member and encapsulating at least a portion of the electronic component using the curable composition of the above embodiment. Examples of methods for encapsulating electronic components or electronic component devices include transfer molding, compression molding, and injection molding. Transfer molding can be performed under conditions of, for example, a mold temperature of 130 to 180°C, a molding pressure of 6 to 10 MPa, and a molding time of 60 to 120 seconds. The heating conditions for post-curing are, for example, 150 to 180°C and 2 to 16 hours.

[0191] <Examples of Embodiments> Examples of embodiments are listed below. The present invention is not limited to the following embodiments. (1) A method for producing a curable composition, comprising: mixing a liquid A containing a compound having a vinylphenyl group and a solvent with a polymerization inhibitor B to obtain a liquid B, removing the solvent from the liquid B to obtain a mixture containing the compound having a vinylphenyl group and the polymerization inhibitor B, and obtaining a curable composition using the mixture. (2) A method for producing a curable composition according to (1) above, wherein obtaining a curable composition using the mixture comprises mixing the mixture with a polymerization inhibitor C to obtain a curable composition. (3) A method for producing a curable composition according to (1) or (2) above, wherein the polymerization inhibitor B contains at least one compound selected from the group consisting of a phenothiazine compound and a TEMPO compound. (4) A method for producing a curable composition according to (2) or (3) above, wherein the polymerization inhibitor C contains a TEMPO compound. (5) A method for producing a curable composition according to any of (2) to (4) above, wherein the polymerization inhibitor B and the polymerization inhibitor C contain a TEMPO compound. (6) The method for producing a curable composition according to any one of (1) to (5) above, wherein the amount of the solvent remaining in the mixture is 1.0 mass% or less. (7) The method for producing a curable composition according to any one of (1) to (6) above, wherein the difference between the weight-average molecular weight of the compound having a vinylphenyl group contained in Liquid A or Liquid B and the weight-average molecular weight of the mixture is 700 or less. (8) The method for producing a curable composition according to any one of (1) to (7) above, wherein the viscosity of the mixture at 60°C is 5.0 Pa s or less. (9) The method for producing a curable composition according to any one of (1) to (8) above, wherein the compound having a vinylphenyl group includes a compound represented by the following formula (b3): (In the formula, B ｈｂ each independently represents a hydrogen atom, a group represented by the following formula (Ba), or a group represented by the following formula (Bz), and at least one B ｈｂ is a group represented by the following formula (Bz). (In the formula, A represents an alkyl group, and * represents a bonding position.) (wherein * represents a bonding position.)) (10) A mixture for a curable composition, comprising a compound having a vinylphenyl group and a polymerization inhibitor B, having a solvent content of 1.0 mass% or less, and having a viscosity of 5.0 Pa s or less at 60°C. The disclosure of this application is related to the subject matter described in Japanese Patent Application No. 2024-122662, filed on July 29, 2024, the entire disclosure of which is incorporated herein by reference.

[0192] The embodiments of the present invention will be described in more detail with reference to examples, but the embodiments of the present invention are not limited to the following examples.

[0193] <Synthesis of Vinylphenyl Compound> (Synthesis Example: Synthesis of Vinylphenyl Compound) An aromatic hydrocarbon, chloromethylstyrene, a phase transfer catalyst, a polymerization inhibitor, and a solvent listed in Table 1 were added to a 500 mL reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet. The resulting composition was stirred at 40°C while blowing nitrogen into it at a flow rate of 50 mL / min. Next, a basic compound listed in Table 1 was added dropwise over 20 minutes, and the mixture was further stirred at 60°C for 9 hours. Nitrogen blowing was continued during the reaction. The composition was cooled to room temperature (25°C), neutralized with a 10% by weight aqueous hydrochloric acid solution, and then washed twice with pure water. After that, a portion of the toluene was distilled off under reduced pressure, and the resulting viscous liquid was washed with methanol to obtain a solution of a vinylphenyl compound with a solids concentration of 60% by weight. The resulting solution was used as a measurement sample to measure the weight-average molecular weight of the vinylphenyl compound. The measurement results are shown in Table 1. The vinylphenyl compound was １ H-nuclear magnetic resonance ( １ H-NMR analysis confirmed that the compound had a structure in which substantially all of the two hydrogen atoms directly bonded to the carbon atom at position 1 of indene were substituted with vinylbenzyl groups (vinylphenylmethyl groups). GPC analysis confirmed that the vinylphenyl compound was a mixture of a compound having two vinylbenzyl groups and a compound having three vinylbenzyl groups, and that the average number of vinylbenzyl groups was in the range of 1.6 to 2.6.

[0194] In the examples, the weight-average molecular weight (Mw) was measured under the following conditions. The weight-average molecular weight (Mw) was calculated by gel permeation chromatography (GPC) from a calibration curve using standard polystyrene. The calibration curve was approximated by a cubic equation using standard polystyrene: TSKstandard POLYSTYRENE (Types: A-2500, A-5000, F-20, F-80) (Tosoh Corporation). Apparatus: High-speed GPC apparatus HLC-8320GPC (Tosoh Corporation) Detector: Ultraviolet absorption detector UV-8320 (Tosoh Corporation) Column: Guard column; TSKgel guard column Super (HZ)-M + Column; TSKgel SuperMultipore HZ-M (2 columns), Reference column; TSKgel Super H-RC (2 columns) (all Tosoh Corporation) Column size: 4.6 x 20 mm (guard column), 4.6 x 150 mm (column), 6.0 x 150 mm (reference column) Eluent: Tetrahydrofuran Sample concentration: 10 mg / 1 mL Injection volume: 20 μL or 2 μL Flow rate: 0.35 mL / min Measurement temperature: 40°C

[0195] The compounds listed in Table 1 are as follows: In Table 1, the unit for each compound is "parts by mass."

[0196] (Aromatic hydrocarbons) Indene: molecular weight 116.2 (Chloromethylstyrene) CMS: a mixture of o-chloromethylstyrene and p-chloromethylstyrene, Wujin Linchuan Chemical Co., Ltd., o-chloromethylstyrene content of 17% by mass, p-chloromethylstyrene content of 83% by mass (Phase transfer catalyst) Tetrabutylphosphonium bromide: Kanto Chemical Co., Ltd. (Polymerization inhibitor A) Phenothiazine (5% weight loss temperature (Td5): 180°C) (Organic solvent) Toluene (Basic compound) Aqueous sodium hydroxide solution: Kanto Chemical Co., Ltd., concentration 48% by mass

[0197]

[0198] (Measurement of 5% weight loss temperature (Td5) of polymerization inhibitor) In the examples, the 5% weight loss temperature (Td5) of the polymerization inhibitor was measured using a TG-DTA device ("TG / DTA7300" manufactured by Hitachi High-Tech Science Corporation). The measurement was carried out using 1.0 mg of the polymerization inhibitor under conditions of a nitrogen atmosphere, a temperature rise rate of 5°C / min, and a measurement temperature range of 40 to 600°C.

[0199] <Solvent Removal (Step (1))> (Solvent Removal Example 1 (Preparation of Mixture 1)) 100.0 parts by mass of the vinylphenyl compound solution obtained in Synthesis Example (solvent: toluene, solids concentration: 60% by mass) and 0.2 parts by mass of 3,7-dioctylphenothiazine were added to a container and stirred at room temperature (25°C) for 1 hour. The mixture obtained after stirring was placed in a metal tray and allowed to stand in a vacuum dryer at a pressure of 0.1 MPa or less and a temperature of 70°C for 5 hours to remove the solvent, thereby obtaining Mixture 1. The difference in weight-average molecular weight, the content of residual toluene in Mixture 1, and the solubility in tetrahydrofuran (THF solubility) and viscosity of Mixture 1 are shown in Table 2. The difference in weight-average molecular weight is the difference between the weight-average molecular weight when a solution of the vinylphenyl compound is used as the measurement sample and the weight-average molecular weight when Mixture 1 is used as the measurement sample (difference in weight-average molecular weight = (weight-average molecular weight of the mixture obtained by removing the solvent) - (weight-average molecular weight of the vinylphenyl compound before removing the solvent)).

[0200] (Solvent Removal Examples 2 to 10: Preparation of Mixtures 2 to 10) Mixtures 2 to 10 were prepared in the same manner as Solvent Removal Example 1, except that polymerization inhibitor B shown in Table 2 was used, and the content of residual toluene and other factors were measured. Mixture 10 is an example that did not contain polymerization inhibitor B. The results are shown in Table 2.

[0201] The compounds listed in Table 2 are as follows. In Table 2, the unit for each compound is "parts by mass." The content of polymerization inhibitor A is about 0.05 to 0.1 mass% based on the mass of the vinylphenyl compound.

[0202] (Polymerization inhibitor B) OH-TEMPO: 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (Td5: 117°C) Sebacic acid BisTEMPO: bis(2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl) sebacate (Td5: 227°C) 3,7-dioctylphenothiazine (Td5: 245°C) 3,7-dicumylphenothiazine (Td5: 313°C)

[0203] The residual toluene content, viscosity, and solubility in tetrahydrofuran (THF) were measured or evaluated by the following methods.

[0204] (Measurement of Residual Toluene Content) 1.0 g of the mixture was added to 10.0 g of THF (room temperature (25°C)) to prepare a THF solution. Using a gas chromatograph ("GC-4000 Plus" manufactured by GL Sciences Inc.), the THF solution was heated to 60°C at a heating rate of 60°C / min, then heated from 60°C to 150°C at a heating rate of 10°C / min, and then heated from 150°C to 260°C at a heating rate of 20°C / min, and then held at 260°C for 30 minutes, and the amount of toluene evaporated was measured. The amount of toluene contained in the mixture was calculated from the mass of the mixture and the amount of toluene evaporated.

[0205] (Evaluation of Solubility in Tetrahydrofuran (THF)) 1.0 g of the mixture was added to a 30 mL glass bottle containing 10.0 g of THF (room temperature (25°C)), and the mixture was shaken several times. After shaking, the glass bottle was left to stand at room temperature (25°C) for 10 minutes, and it was confirmed whether the mixture had dissolved in THF or remained as a solid. As the reaction of the vinylphenyl compound progresses within the mixture, the solubility of the mixture in THF decreases. Therefore, it can be said that if the solubility in THF is good, the reaction of the vinylphenyl compound within the mixture is suppressed, and the fluidity of the mixture is maintained.

[0206] (Viscosity Measurement) An E-type viscometer ("E-type digital viscometer TVE-25H" manufactured by Advantec Toyo Co., Ltd.) was used, and the measurement temperature was 60°C and the rotation speed was 50 min. ー１ The viscosity of the mixture was measured under the following conditions: 1.0 g of the mixture was weighed out, and after leaving it to stand for 1 minute, the measurement was started, and the value was read 1 minute after the start of the measurement.

[0207]

[0208] <Preparation of Curable Composition (Step (2))> (Curable Compositions 1 to 10) The mixture after removal of the solvent was premixed (dry blended) with the compounds listed in Table 3, and then kneaded in a twin-screw kneader (kneading temperature 120°C). The kneaded mixture was cooled and pulverized to produce a powdery curable composition. The melt viscosity and spiral flow of the curable composition were measured. The measurement results are shown in Table 3.

[0209] The compounds listed in Table 3 are as follows. In Table 3, the unit for each compound is "parts by mass." "○" indicates that the curable composition contains the compound listed in the left column. The content of polymerization inhibitor B is approximately 0.1 to 0.4 mass% based on the mass of the vinylphenyl compound. The average particle size of the inorganic filler was measured by the method described above. The content (vol %) of the inorganic filler is the ratio of the volume of silica based on the volume of the curable composition.

[0210] (Vinylphenyl compounds) Vinylphenyl compound: a mixture containing the vinylphenyl compound (vinylbenzyl compound) obtained in Synthesis Example (Polymerization inhibitor C) OH-TEMPO: 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (Td5: 117°C) Sebacic acid BisTEMPO: bis(2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl) sebacate (Td5: 227°C) TEMPO: 2,2,6,6-tetramethylpiperidine 1-oxyl (Td5: 96°C) Phenothiazine (Td5: 180°C) 3,7-dioctylphenothiazine (Td5: 245°C) (Vinyl compounds) Maleimide compound: polyphenylmethane maleimide, Daiwa Chemical Industry Co., Ltd. "BMI-2300" (Other raw materials) Coupling agent: N-phenyl-3-aminopropyltrimethoxysilane, Shin-Etsu Chemical Co., Ltd. "KBM-573" Mold release agent: Montan acid ester wax, Clariant Japan Co., Ltd. "HW-E" Colorant: Carbon black, Mitsubishi Chemical Corporation "MA600" Inorganic filler: Silica (average particle size 26.9 μm), Zhejiang Huafei Electronic Materials Co., Ltd. "SS-205"

[0211] The melt viscosity and spiral flow were measured by the following methods: (Measurement of Melt Viscosity) The melt viscosity of 2.0 g of the curable composition at 175°C was measured using a high-speed flow tester ("CFT-500EX" manufactured by Shimadzu Corporation, nozzle diameter 1 mm, nozzle length 10 mm, load 10 kg).

[0212] (Measurement of Spiral Flow (SF)) Using a spiral flow measurement mold conforming to EMMI-1-66, the curable composition was molded with a transfer molding machine (Technomarushi Co., Ltd.) under conditions of a mold temperature of 175°C, a molding time of 120 seconds, and a molding pressure of 6.9 MPa, and the flow distance was measured.

[0213] (Other Curable Compositions) Mixtures 3 and 5 to 9 were used to prepare curable compositions, and the melt viscosity and spiral flow were measured in the same manner as for curable composition 4. As with curable compositions 4 to 7, the results showed that the melt viscosity was low and the spiral flow was high.

[0214] <Preparation of Cured Product> A cured product was prepared using the curable composition, and the flexural strength was measured by the following method. The measurement results are shown in Table 3.

[0215] (Measurement of bending strength) The encapsulating composition was molded using a transfer molding machine (Technomarushi Co., Ltd.) under conditions of a mold temperature of 175°C, a molding time of 120 seconds, and a molding pressure of 6.9 MPa to produce a cured product having a shape of 70 mm x 10 mm x 3 mm. A three-point support bending test in accordance with JIS-K-6911 (2006) was performed at room temperature (25°C) using a Tensilon universal material testing machine (manufactured by A&D Co., Ltd., "RTH-2430") to determine the bending strength of the cured product.

[0216]

[0217] Cured products were prepared using each of the "other curable compositions" and their bending strengths were measured in the same manner as for curable composition 4. As with curable compositions 4 to 7, the bending strengths were found to be high.

Claims

1. A method for producing a curable composition, comprising: mixing liquid A, which contains a compound having a vinylphenyl group and a solvent, with a polymerization inhibitor B to obtain liquid B; removing the solvent from liquid B to obtain a mixture containing the compound having a vinylphenyl group and the polymerization inhibitor B; and using the mixture to obtain a curable composition.

2. The method for producing a curable composition according to claim 1, wherein obtaining a curable composition using the mixture comprises mixing the mixture with a polymerization inhibitor C to obtain a curable composition.

3. The method for producing a curable composition according to claim 1 or 2, wherein the polymerization inhibitor B comprises at least one compound selected from the group consisting of phenothiazine compounds and TEMPO compounds.

4. The method for producing a curable composition according to claim 2 or 3, wherein the polymerization inhibitor C includes a TEMPO compound.

5. The method for producing a curable composition according to any one of claims 2 to 4, wherein the polymerization inhibitor B and the polymerization inhibitor C contain a TEMPO compound.

6. The method for producing a curable composition according to any one of claims 1 to 5, wherein the amount of the solvent remaining in the mixture is 1.0 mass % or less.

7. The method for producing a curable composition according to any one of claims 1 to 6, wherein the difference between the weight average molecular weight of the compound having a vinylphenyl group contained in Liquid A or Liquid B and the weight average molecular weight of the mixture is 700 or less.

8. The method for producing a curable composition according to any one of claims 1 to 7, wherein the viscosity of the mixture at 60°C is 5.0 Pa·s or less.

9. A method for producing a curable composition according to any one of claims 1 to 8, wherein the compound having a vinylphenyl group includes a compound represented by the following formula (b3): (In the formula, B ｈｂ each independently represents a hydrogen atom, a group represented by the following formula (Ba), or a group represented by the following formula (Bz), and at least one B ｈｂ is a group represented by the following formula (Bz). (In the formula, A represents an alkyl group, and * represents a bonding position.) (In the formula, * represents the bonding position.) 10. A mixture for a curable composition, containing a compound having a vinylphenyl group and a polymerization inhibitor B, having a solvent content of 1.0 mass% or less, and having a viscosity at 60°C of 5.0 Pa·s or less.

Images