Divinylbenzylfluorene compound and method for producing the same

Abstract

Provided is a divinylbenzylfluorene compound capable of achieving both solubility in methyl ethyl ketone and a high melting point. [Solution] A divinylbenzylfluorene compound according to an embodiment of the present invention is represented by the general formula (1). In formula (1), R1, R2, and R3 each independently represent a hydrocarbon group having 1 to 5 carbon atoms; a, b and c each independently represent an integer of 0 to 4; and the ratio of p, p-isomers, of which both of the two vinylbenzyl groups in formula (1) are para isomers, is 20 to 50%.

Description

Divinylbenzylfluorene compounds and methods for producing the same

[0001] Embodiments of the present invention relate to divinylbenzylfluorene compounds, curable resin compositions containing the same, cured products thereof, and methods for producing divinylbenzylfluorene compounds.

[0002] Conventionally, divinylbenzylfluorene compounds have been known as compounds used in resin materials such as printed circuit boards. For example, Patent Document 1 discloses a compound obtained by reacting a fluorene compound with a vinylbenzyl halide compound, where α is the number of moles of the fluorene compound, β1 is the number of moles of the para isomer and β2 is the number of moles of the meta isomer, and (β1 + β2) / α is set to 1.8 to 2.1.

[0003] Patent Document 2 discloses a divinylbenzylfluorene compound characterized by having a melting point of 130°C or less or having no melting point, and discloses that the ratio of p-isomers / (m-isomers + p-isomers) of the vinylbenzyl group of the compound is 0.6 to 1.0.

[0004] International Publication No. 2024 / 111414, Japanese Patent Publication No. 2022-167558

[0005] Because divinylbenzylfluorene compounds have two polymerizable unsaturated bonds, they can be used as components of curable resin compositions that harden with heat, light, electron beams, etc. From the viewpoint of designing the formulation of such curable resin compositions, it is desirable for divinylbenzylfluorene compounds to have improved solubility in organic solvents such as methyl ethyl ketone. Furthermore, from the viewpoint of processing conditions when manufacturing resin products using curable resin compositions, it is sometimes desirable for divinylbenzylfluorene compounds to have a high melting point.

[0006] Furthermore, Patent Document 1 discloses the number of moles of the para and meta isomers of a vinylbenzyl halide compound used in the production of a divinylbenzylfluorene compound. Patent Document 2 discloses the ratio of the para isomer to the total amount of the para and meta isomers of vinylbenzyl groups in a divinylbenzylfluorene compound. However, these patent documents do not disclose how to set the ratio of p,p-isomers, in which both vinylbenzyl groups in one molecule are para isomers, within a specific range, nor do they disclose how this can achieve both a high melting point and solubility.

[0007] The embodiments of the present invention aim to provide a divinylbenzylfluorene compound that can achieve both solubility in methyl ethyl ketone and a high melting point.

[0008] The present invention includes the embodiments shown below. [1] A divinylbenzylfluorene compound represented by the following general formula (1), R in general formula (1) １ , R ２ and R ３ A divinylbenzylfluorene compound in which each of the following groups independently represents a hydrocarbon group having 1 to 5 carbon atoms, a, b, and c independently represent an integer from 0 to 4, and the ratio of p,p-isomers, in which both vinylbenzyl groups in general formula (1) are para isomers, is 20 to 50%.

[0009] [2] The divinylbenzylfluorene compound according to [1], wherein the solubility in methyl ethyl ketone at 22°C is 20% by mass or more.

[0010] [3] The divinylbenzylfluorene compound according to [1] or [2], wherein the melting point is higher than 130°C and 200°C or lower.

[0011] [4] A curable resin composition comprising a divinylbenzylfluorene compound as described in any one of items [1] to [3].

[0012] [5] A cured product obtained by curing a divinylbenzylfluorene compound according to any one of items [1] to [3], or a curable resin composition according to [4].

[0013] [6] The method comprises reacting a fluorene compound represented by the following general formula (2) with a vinyl benzyl halide compound represented by the following general formula (3) having a meta / para molar ratio of 30 / 70 to 60 / 40 in an aprotic polar solvent with a boiling point of less than 100°C in the presence of an alkali, and precipitating the obtained product in a mixed solvent of an alcohol having 1 to 4 carbon atoms and water. R in general formula (2) １ and R ２ Each of the following independently represents a hydrocarbon group having 1 to 5 carbon atoms, and each of the following independently represents an integer from 0 to 4: R in general formula (3) ３ A method for producing a divinylbenzylfluorene compound, wherein represents a hydrocarbon group having 1 to 5 carbon atoms, c represents an integer from 0 to 4, and X represents a halogen atom.

[0014] [7] A method for producing a divinylbenzylfluorene compound according to [6], further comprising washing the product obtained by the above reaction with water, and then performing the above precipitation after washing with water.

[0015] [8] The method for producing a divinylbenzylfluorene compound according to [6] or [7], wherein the aprotic polar solvent is a methyl ethyl ketone.

[0016] [9] A method for producing a divinylbenzylfluorene compound according to any one of [6] to [8], wherein the amount of water in the mixed solvent is 20 to 40% by mass.

[0017] According to this embodiment, by having a p,p-isomer ratio of 20 to 50%, a divinylbenzylfluorene compound can be provided that has a high melting point while improving solubility in methyl ethyl ketone.

[0018] The production method according to this embodiment can improve the yield of the divinylbenzylfluorene compound.

[0019] The divinylbenzylfluorene compound according to this embodiment is represented by the following general formula (1).

[0020] R in equation (1) １ , R ２and R ３ each independently represents a substituent that substitutes a hydrogen atom on an aromatic ring, and each independently represents a hydrocarbon group having 1 to 5 carbon atoms, preferably represents a hydrocarbon group having 1 to 3 carbon atoms, and more preferably represents a hydrocarbon group having 1 or 2 carbon atoms. The hydrocarbon group is preferably an alkyl group. In addition, when a plurality of R １ , R ２ and R ３ are each present in one molecule, they may be the same as or different from each other.

[0021] In formula (1), a, b and c each independently represent an integer of 0 to 4, preferably 0 or 1, more preferably 0. That is, the compound is preferably unsubstituted divinylbenzylfluorene having no substituent R １ to R ３

[0022] In the divinylbenzylfluorene compound according to the present embodiment, the proportion of the p,p-isomer, in which both of the two vinylbenzyl groups in formula (1) are para-form, is 20 to 50%. For the divinylbenzylfluorene compound, the higher the proportion of the p,p-isomer, the better the solubility in organic solvents such as methyl ethyl ketone (MEK). On the other hand, if the proportion of the p,p-isomer is too high, the melting point will decrease. By setting the proportion of the p,p-isomer to 20 to 50%, the solubility in MEK can be improved while maintaining a high melting point. The proportion of the p,p-isomer is preferably 23 to 45%, more preferably 25 to 40%.

[0023] Here, the proportion of the p,p-isomer is the proportion of the peak area of peaks derived from benzylic carbon determined by １３ C-NMR, and corresponds to the amount (molar ratio) of the p,p-isomer when the total amount of all isomers of the divinylbenzylfluorene compound is taken as 100% (the same applies to the total proportion of the p,m-isomer and the m,m-isomer described below). The detailed measurement method is as described in the Examples section.

[0024] ​Regarding a vinylbenzyl group, the para-isomer (p-vinylbenzyl) refers to a structure in which the bonding position of the vinyl group relative to the benzylic carbon (benzyl carbon) is the para-position. The meta-isomer (m-vinylbenzyl) refers to a structure in which the bonding position of the vinyl group relative to the benzyl carbon is the meta-position. The same applies to the para-isomer and meta-isomer of vinylbenzyl halide compounds.

[0025] The p,p-isomer is represented by the following general formula (1-1). R in formula (1-1) １ , R ２ , R ３ , a, b and c are each R in formula (1) １ , R ２ , R ３ , which is the same as a, b and c.

[0026] In one embodiment, the divinylbenzyl fluorene compound comprises a p,p-isomer, as well as a p,m-isomer and / or an m,m-isomer. The total ratio of the p,m-isomer and the m,m-isomer is preferably 50 to 80%, more preferably 55 to 77%, and still more preferably 60 to 75%. The total ratio of the p,p-isomer, the p,m-isomer and the m,m-isomer is not particularly limited, and may be, for example, 80% or more, 85% or more, 90% or more, 95% or more, or 100%.

[0027] Here, the p,m-isomer is an isomer in which one of the two vinylbenzyl groups in the above formula (1) is a para-isomer and the other is a meta-isomer, and is thus represented by the following general formula (1-2). R in formula (1-2) １ , R ２ , R ３ , a, b and c are each R in formula (1) １ , R ２ , R ３ , which is the same as a, b and c.

[0028] The m,m-isomer is an isomer in which both of the two vinylbenzyl groups in the above formula (1) are meta-isomers, and is thus represented by the following general formula (1-3). R in formula (1-3) １ , R ２, R ３ a, b, and c are R in equation (1), respectively. １ , R ２ , R ３ , are the same as a, b, and c.

[0029] As described above, the divinylbenzylfluorene compound according to the embodiment has a high melting point while exhibiting excellent solubility in MEK due to the ratio of p,p-isomers being 20 to 50%. In one embodiment, the solubility of the divinylbenzylfluorene compound in MEK is preferably 20% by mass or more. Here, solubility is the concentration of the saturated solution at 22°C, i.e., the mass percentage of the divinylbenzylfluorene compound in 100% by mass of the saturated solution, and the detailed measurement method is described in the Examples section. The solubility in MEK is more preferably 21% by mass or more. Since a higher solubility is preferable, there is no particular upper limit, but it may be 30% by mass (for example, 20 to 30% by mass) or 28% by mass (for example, 21 to 28% by mass).

[0030] In one embodiment, the melting point of the divinylbenzylfluorene compound is preferably higher than 130°C and 200°C or lower. Here, the melting point is the melting point under 1 atmosphere, and the detailed measurement method is as described in the Examples section. The melting point of the divinylbenzylfluorene compound is more preferably higher than 130°C and 150°C or lower, and more preferably between 131°C and 140°C.

[0031] In one embodiment, the solubility of the divinylbenzylfluorene compound in toluene at 22°C is preferably greater than 20% by mass, and more preferably 20.5% by mass or more. Since higher solubility is preferable, there is no particular upper limit, but it may be 30% by mass (for example, 20-30% by mass) or 25% by mass (for example, 20.5-25% by mass).

[0032] In one embodiment, the exothermic peak temperature of the divinylbenzylfluorene compound is preferably 135°C to 200°C, more preferably 140°C to 160°C, and even more preferably 140°C to 150°C. Here, the exothermic peak temperature is the temperature at the exothermic peak measured by differential scanning calorimetry (DSC), and the detailed measurement method is described in the Examples section.

[0033] The method for producing the divinylbenzylfluorene compound according to this embodiment is not particularly limited. In one embodiment, a fluorene compound represented by the following general formula (2) and a vinylbenzyl halide compound represented by the following general formula (3) are reacted in a specific solvent in the presence of an alkali, and the resulting product is precipitated in a mixed solvent of alcohol and water to obtain the divinylbenzylfluorene compound.

[0034] Here, the vinylbenzyl halide compound used has a molar ratio of 30 / 70 to 60 / 40 for the meta-isomer and para-isomer. The solvent used during the reaction is an aprotic polar solvent with a boiling point of less than 100°C. The solvent used for precipitation is a mixed solvent of an alcohol having 1 to 4 carbon atoms and water. By employing this production method, a divinylbenzylfluorene compound with a p,p-isomer ratio of 20 to 50% can be obtained, and the yield can be improved.

[0035] R in equation (2) １ , R ２ a and b are R in equation (1), respectively. １ , R ２ , are the same as a and b. Note that the fluorene compound may be used alone, or two or more compounds with different substituents may be used in combination.

[0036] R in equation (3) ３ and c are R in equation (1), respectively. ３And is the same as c. X represents a halogen atom, preferably a chlorine atom or a bromine atom, and more preferably a chlorine atom. Note that the vinyl benzyl halide compound may be used alone, or two or more compounds with different substituents may be used in combination.

[0037] In the vinyl benzyl halide compound represented by formula (3), the molar ratio of the meta-isomer to the para-isomer is 30 / 70 to 60 / 40, preferably 35 / 65 to 55 / 45, as described above. By having a molar ratio of 60 / 40 or less, the proportion of p,p-isomers can be increased. By having a molar ratio of 30 / 70 or more, the proportion of p,p-isomers can be decreased.

[0038] In vinyl benzyl halide compounds, the total ratio of the meta-isomer to the para-isomer is preferably 80 mol% or more, more preferably 90 mol% or more, more preferably 95 mol% or more, and may even be 100 mol%.

[0039] As the reaction solvent, an aprotic polar solvent with a boiling point of less than 100°C is used, as described above. This allows for precipitation in a mixed solvent of alcohol and water after the reaction. More preferably, an aprotic polar solvent with low solubility in water is used as the reaction solvent. Specifically, it is preferable that the solubility in water at 22°C is 30% by mass or less, more preferably 5 to 30% by mass, more preferably 10 to 28% by mass, and even more preferably 15 to 25% by mass. Examples of such aprotic polar solvents include methyl ethyl ketone (MEK) and 2-methyltetrahydrofuran, with MEK being particularly preferred among these.

[0040] The alkali used in the reaction can be an alkali metal or alkaline earth metal hydroxide, alkoxide, or hydride, such as sodium hydroxide, potassium hydroxide, sodium methoxide, sodium ethoxide, sodium hydride, or potassium hydride. One of these may be used, or two or more may be used in combination. The amount of alkali used is not particularly limited; for example, it may be about 1.1 to 3.0 equivalents per equivalent of hydrogen at position 9 of the fluorene compound. In one embodiment, the alkali may be added to the reaction system containing the reaction solvent as an aqueous solution. When a reaction solvent with low solubility in water is used, the aqueous alkali solution and the reaction solvent will not be miscible, even if some dissolve, and the reaction will proceed in a finely dispersed state by stirring.

[0041] A phase transfer catalyst may be used during the reaction. Onium salts can be used as phase transfer catalysts, including, for example, quaternary ammonium compounds such as tetrabutylammonium bromide, tetrabutylammonium bisulfate, benzyltrimethylammonium chloride, and tricaprylmethylammonium chloride, and quaternary phosphonium compounds such as tetrabutylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium chloride, and tetraphenylphosphonium bromide. These may be used individually or in combination of two or more. The amount of phase transfer catalyst used is not particularly limited; for example, it may be around 0.01 to 0.2 equivalents per equivalent of hydrogen at position 9 of the fluorene compound.

[0042] The reaction temperature and reaction time are not particularly limited; for example, they may be 30 to 100°C for 0.5 to 20 hours.

[0043] After the reaction is complete, it is preferable to wash the obtained product with water and then perform the precipitation described above, which can increase the purity of the divinylbenzylfluorene compound. Specifically, an acid is added to the liquid after the reaction, which contains the solution of the aprotic polar solvent in which the product is dissolved and an aqueous solution of alkali, to neutralize it, and the aqueous layer is separated and removed to remove the salt produced by neutralization. After removing the aqueous layer, water is added to the organic layer (the solution of the aprotic polar solvent in which the product is dissolved) and stirred, and the aqueous layer is separated and removed to wash the product with water. The washing with water may be repeated several times. Next, the organic layer containing the above product after removing the aqueous layer is added to a mixed solvent of alcohol and water as a precipitation solvent, and precipitated in the mixed solvent. This yields the divinylbenzylfluorene compound according to the embodiment.

[0044] As the precipitation solvent, a mixed solvent of an alcohol having 1 to 4 carbon atoms (hereinafter also referred to as a lower alcohol) and water can be used to improve the yield. Examples of lower alcohols include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, and tert-butyl alcohol. Any one of these may be used, or two or more may be used in combination. Preferably, methanol and / or ethanol is used, and more preferably methanol.

[0045] Regarding the ratio of lower alcohol to water in the mixed solvent, it is preferable that the amount of water in the mixed solvent is 20 to 40% by mass, that is, 20 to 40% by mass of water and 60 to 80% by mass of lower alcohol. By setting the water ratio in this way, it becomes easier to adjust the ratio of p,p-isomers within the range of 20 to 50%. In addition, a small water ratio can improve the drying efficiency of the product after precipitation. More preferably, the mixed solvent contains 25 to 35% by mass of water and 65 to 75% by mass of lower alcohol.

[0046] The divinylbenzylfluorene compound according to this embodiment can be cured alone by heating or the like, but it may also be formed into a curable resin composition by blending it with various components such as a curing agent. By curing the divinylbenzylfluorene compound or the curable resin composition with heat, light, electron beam, or the like, a cured product according to this embodiment can be obtained.

[0047] The curable resin composition according to this embodiment contains the above-mentioned divinylbenzylfluorene compound, and may also contain various additives such as curing agents, copolymerizable monomers, oligomers and / or polymers, inorganic fillers, photopolymerization initiators, polymerization inhibitors, flame retardants, and colorants.

[0048] Examples of curing agents include benzoyl peroxide, cumene hydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyn-3, t-butylcumyl peroxide, methyl ethyl ketone peroxide, and dicumyl peroxide.

[0049] Examples of monomers, oligomers, and / or polymers copolymerizable with divinylbenzylfluorene compounds include oligomers or polymers having polymerizable unsaturated groups, such as vinyl ester resins, unsaturated polyester resins, and diallyl phthalate resins, as well as monofunctional or polyfunctional (meth)acrylic acid derivatives such as styrene, vinyltoluene, and divinylbenzene.

[0050] The applications of the divinylbenzylfluorene compound and curable resin composition according to this embodiment are not particularly limited and include various resin materials such as printed circuit boards, semiconductor encapsulants, and optical components.

[0051] The present invention will be described in more detail below based on examples and comparative examples, but it is not limited thereto.

[0052] <Measurement and Evaluation Method> [p,p-isomer ratio] For each product of the Examples and Comparative Examples, approximately 30 mg was dissolved in approximately 1 g of deuterated chloroform (containing 0.03% by mass TMS (tetramethylsilane)) to prepare a sample. The sample was transferred to a 5 mm diameter NMR measuring tube and analyzed using a nuclear magnetic resonance spectrometer (manufactured by JEOL Ltd.) by the reversed decoupling method. １３ ¹³C-NMR was measured. The measurement conditions were room temperature, pulse width 45°, delay time 50 seconds, and number of integrations 512 times.

[0053] １３ 13C-NMR measurements revealed that in Examples 1 and 2 and Comparative Examples 1 and 2, four peaks originating from benzyl carbon were detected, each with a peak top at 45.0 ppm, 45.2 ppm, 45.3 ppm, and 45.5 ppm, respectively. On the other hand, in Comparative Example 3, which was synthesized using vinyl benzyl chloride with a meta / para molar ratio of 5 / 95, no peak was detected at 45.3 ppm, while a significantly larger peak area was detected at 45.2 ppm.

[0054] In the following examples and comparative examples, fluorene is reacted with vinylbenzyl chloride, and a mixture of the meta and para isomers of vinylbenzyl chloride is used. Therefore, divinylbenzylfluorene compounds (9,9-bis(vinylbenzyl)fluorene) can be synthesized as a p,p-isomer represented by the following formula (1-1A), a p,m-isomer represented by the following formula (1-2A), and an m,m-isomer represented by the following formula (1-3A).

[0055] ​Therefore, the four types of benzyl carbons mentioned above are the benzyl carbon of the p,p-isomer, the meta-isomer of the p,m-isomer, the para-isomer of the p,m-isomer, and the m,m-isomer of the benzyl carbon. As described above, in Comparative Example 3, the 45.3 ppm peak was not detected, and the 45.2 ppm peak area was detected as being exceptionally large. This indicates that the 45.2 ppm peak belongs to the p,p-isomer of the benzyl carbon, and the 45.3 ppm peak belongs to the m,m-isomer of the benzyl carbon. Accordingly, the ratio of the 45.2 ppm peak area to the sum of the four peak areas around 45 ppm was calculated as the p,p-isomer ratio.

[0056] [Melting Point and Exothermic Peak Temperature] For each product in the Examples and Comparative Examples, the melting point and exothermic peak temperature were measured using a differential scanning calorimetry device (manufactured by Rigaku Corporation) under a nitrogen atmosphere, by raising the temperature from room temperature to 350°C at a heating rate of 10°C / min.

[0057] [Solubility] For each product in the examples and comparative examples, 5 g was placed in a screw-top bottle, 11.7 g of toluene or methyl ethyl ketone (MEK) was added, and the mixture was shaken well. The mixture was then left to stand overnight in a constant temperature and humidity chamber at 22°C. The supernatant was filtered through a syringe filter (pore size 0.45 μm) to obtain the saturated solution. For approximately 1 g of the saturated solution, the solid content was measured using an infrared moisture meter (manufactured by Kett Scientific Research Institute Co., Ltd.) at a temperature of 120°C for 30 minutes. The concentration of the saturated solution was calculated from the solid content and was used as the solubility of each product.

[0058] (Example 1) In a 3 L reactor equipped with a condenser and a stirrer, 149.6 g of fluorene, 274.6 g of vinyl benzyl chloride (meth / para isomer (molar ratio) = 50 / 50, trade name: CMS-P, manufactured by AGC Seimi Chemical Co., Ltd.), 13.2 g of tetrabutylammonium bromide, and 150.0 g of MEK were added and dissolved at 40°C. Next, 300.0 g of 48% by mass aqueous sodium hydroxide solution was added, and the reaction mixture was heated to 50-60°C and continued for 6 hours. Then, 1050.9 g of MEK was added to dilute it. 330.0 g of water and 196.8 g of 35% by mass hydrochloric acid were added and stirred at 45-55°C for 15 minutes, and the mixture was allowed to stand to separate and remove the aqueous layer. Furthermore, 311.9 g of water was added and the mixture was stirred at 45-55°C. After allowing it to stand and separating and removing the aqueous layer, this process was repeated twice. The resulting organic layer was then added dropwise to a mixed solvent of 1949.5 g of water and 5848.4 g of methanol (MeOH). The precipitated solid was collected and vacuum-dried overnight at 40°C to obtain 307.1 g of product (yield 85.6% by mass).

[0059] (Example 2) In a 1 L reactor equipped with a condenser and a stirrer, 74.8 g of fluorene, 103.0 g of vinyl benzyl chloride (meth / para isomer (molar ratio) = 50 / 50, trade name: CMS-P, manufactured by AGC Seimi Chemical Co., Ltd.), 34.3 g of vinyl benzyl chloride (meth / para isomer (molar ratio) = 5 / 95, trade name: CMS-14, manufactured by AGC Seimi Chemical Co., Ltd.), 6.6 g of tetrabutylammonium bromide, and 75.0 g of MEK were added and dissolved at 40°C. Next, 150.0 g of 48% by mass aqueous sodium hydroxide solution was added, and the reaction solution was heated to 50-60°C and the reaction was continued for 6 hours, after which 525 g of MEK was added to dilute it. 165.0 g of water and 95.6 g of 35% by mass hydrochloric acid were added to the mixture and stirred at 45–55°C for 15 minutes, after which the aqueous layer was allowed to stand and separated and removed. This process of adding another 165.0 g of water, stirring at 45–55°C, and allowing the aqueous layer to stand and removed was repeated twice. The resulting organic layer was then added dropwise to a mixed solvent of 904.0 g of water and 2711.0 g of methanol, and the precipitated solid was collected and vacuum-dried overnight at 40°C to obtain 147.8 g of product (yield 82.3% by mass).

[0060] (Comparative Example 1) In a 1 L reactor equipped with a condenser and a stirrer, 74.8 g of fluorene, 137.3 g of vinyl benzyl chloride (meth / para isomer (molar ratio) = 50 / 50, trade name: CMS-P, manufactured by AGC Seimi Chemical Co., Ltd.), 6.6 g of tetrabutylammonium bromide, and 75.0 g of MEK were added and dissolved at 40°C. Next, 150.0 g of 48% by mass aqueous sodium hydroxide solution was added, and the reaction mixture was heated to 50-60°C and continued for 7 hours. Then, 525 g of MEK was added to dilute it. 165.0 g of water and 95.6 g of 35% by mass hydrochloric acid were added, and the mixture was stirred at 45-55°C for 15 minutes. After standing, the aqueous layer was separated and removed. Furthermore, 151.5 g of water was added and the mixture was stirred at 45-55°C. After allowing it to stand, the aqueous layer was separated and removed twice. The resulting organic layer was then added dropwise to 3400 g of methanol, and the precipitated solid was collected and vacuum-dried overnight at 40°C to obtain 90.7 g of product (yield 50.5% by mass).

[0061] (Comparative Example 2) In a 1 L reactor equipped with a condenser and a stirrer, 74.8 g of fluorene, 137.3 g of vinyl benzyl chloride (meth / para isomer (molar ratio) = 50 / 50, trade name: CMS-P, manufactured by AGC Seimi Chemical Co., Ltd.), 6.6 g of tetrabutylammonium bromide, and 75.0 g of toluene were added and dissolved at 40°C. Next, 150.0 g of 48% by mass aqueous sodium hydroxide solution was added, and the reaction mixture was heated to 50-60°C and continued for 11 hours. Then, 343.4 g of toluene was added to dilute it. 165.0 g of water, 18.8 g of isopropanol, and 95.6 g of 35% by mass hydrochloric acid were added and stirred at 45-55°C for 15 minutes, and the mixture was allowed to stand to separate and remove the aqueous layer. Further, 30.0 g of water and 7.5 g of isopropanol were added, and the mixture was stirred at 45-55°C. After standing, the aqueous layer was separated and removed, and this process was repeated four times. Then, 181.6 g of toluene was added to dilute the mixture. The resulting organic layer was added dropwise to 3738 g of methanol, and the precipitated solid was collected and vacuum-dried overnight at 40°C to obtain 72.2 g of product (yield 40.3% by mass).

[0062] (Comparative Example 3) In a 500 mL reactor equipped with a condenser and a stirrer, 29.9 g of fluorene, 54.9 g of vinyl benzyl chloride (meth / para isomer (molar ratio) = 5 / 95, trade name: CMS-14, manufactured by AGC Seimi Chemical Co., Ltd.), 2.6 g of tetrabutylammonium bromide, and 30.0 g of MEK were added and dissolved at 40°C. Next, 60.0 g of 48% by mass aqueous sodium hydroxide solution was added, and the reaction mixture was heated to 50-60°C and the reaction continued for 6 hours. Then, 210.2 g of MEK was added to dilute it. 66.0 g of water and 39.4 g of 35% by mass hydrochloric acid were added, and the mixture was stirred at 45-55°C for 15 minutes. After standing, the aqueous layer was separated and removed. Further, 62.4 g of water was added and the mixture was stirred at 45-55°C. After allowing it to stand and separating and removing the aqueous layer, this process was repeated twice. The resulting organic layer was then added dropwise to a mixed solvent of 389.9 g of water and 1169.7 g of methanol. The precipitated sticky solid was collected and vacuum-dried overnight at 40°C to obtain 51.5 g of product (yield 71.8% by mass).

[0063] (Comparative Example 4) In a 500 mL reactor equipped with a condenser and a stirrer, 29.9 g of fluorene, 54.9 g of vinyl benzyl chloride (meth / para isomer (molar ratio) = 50 / 50, trade name: CMS-P, manufactured by AGC Seimi Chemical Co., Ltd.), and 30.0 g of dimethyl sulfoxide (DMSO) were added and dissolved at 45°C. Next, 60.0 g of 48% by mass aqueous sodium hydroxide solution was added, and the reaction mixture was heated to 50-60°C and continued for 6 hours. Then, 210.2 g of DMSO was added to dilute it. 66.0 g of water and 39.4 g of 35% by mass hydrochloric acid were added, and the mixture was stirred at 45-55°C for 15 minutes. After standing, the product precipitated. Furthermore, the organic layer and the aqueous layer did not separate, and the subsequent operations could not be carried out.

[0064] The p,p-isomer ratio, melting point, exothermic peak temperature, solubility in toluene, and solubility in MEK were measured and evaluated for the products of Examples 1 and 2 and Comparative Examples 1 to 3. The results are shown in Table 1. In Table 1, "CMS m / p" represents the molar ratio of the meta-isomer / para-isomer of vinyl benzyl chloride used in the reaction.

[0065]

[0066] As shown in Table 1, the product obtained in Example 1 was a divinylbenzylfluorene compound with a p,p-isomer ratio of 25.2%, and a total ratio of p,m-isomers and m,m-isomers of 74.8%. The divinylbenzylfluorene compound had a melting point of 138.9°C, an exothermic peak temperature of 145.2°C, a solubility of 20.7% by mass in toluene, and a solubility of 21.1% by mass in MEK.

[0067] Furthermore, the product obtained in Example 2 was a divinylbenzylfluorene compound with a p,p-isomer ratio of 38.2%, a melting point of 131.1°C, an exothermic peak temperature of 142.4°C, a solubility of 23.9% by mass in toluene, and a solubility of 24.1% by mass in MEK.

[0068] In contrast, the products obtained in Comparative Examples 1 and 2 were divinylbenzylfluorene compounds with a lower p,p-isomer ratio compared to Examples 1 and 2, and exhibited inferior solubility in toluene and MEK. Furthermore, the yields were significantly lower compared to Examples 1 and 2.

[0069] On the other hand, in Comparative Example 3, which used vinyl benzyl chloride with a meta / para molar ratio of 5 / 95, the p,p-isomer ratio of the product was higher and the solubility in toluene and MEK was higher compared to Examples 1 and 2. Specifically, in the solubility measurement, the entire product was dissolved, meaning the solubility was 30% by mass or more. However, in Comparative Example 3, the melting point of the product was significantly lower than in Examples 1 and 2, and consequently the exothermic peak temperature was also lower, raising concerns that the processing conditions would be limited. Furthermore, the yield was also lower compared to Examples 1 and 2.

[0070] As described above, Examples 1 and 2 had a higher p,p-isomer ratio compared to Comparative Examples 1 and 2, resulting in divinylbenzylfluorene compounds with high solubility in toluene and MEK. Furthermore, they had a lower p,p-isomer ratio compared to Comparative Example 3, resulting in a higher melting point. Thus, Examples 1 and 2 were able to achieve both solubility in toluene and MEK and a high melting point. In addition, Examples 1 and 2 were able to obtain divinylbenzylfluorene compounds in higher yields compared to Comparative Examples 1 to 3.

[0071] In Comparative Example 4, where DMSO was used as the reaction solvent, a solid precipitate formed when water and 35% by mass hydrochloric acid were added after the reaction, making it impossible to proceed with the subsequent steps after washing with water.

[0072] The curability of the divinylbenzylfluorene compounds obtained in Examples 1 and 2 was evaluated. Specifically, using a research and development test press (300 x 300 test press, KVHC, manufactured by Kitagawa Seiki Co., Ltd.), the temperature was raised from 20°C to 160°C at a pressure of 10 Pa and a rate of 5°C / min. Then, 10.0 g of the sample was pressed at 160°C for 10 minutes to create a 100 mm x 100 mm x 1 mm thick flat plate. The obtained flat plate was cut to create test pieces with a width of 60 mm, a thickness of 1 mm, and a length of 100 mm. The dielectric constant (Dk) and dielectric loss tangent (Df) at 10 GHz were measured using a split cylinder resonator (manufactured by EM Lab Co., Ltd.). The results are shown in Table 2.

[0073] As shown in Table 2, the cured products obtained by curing the divinylbenzylfluorene compounds of Examples 1 and 2 all exhibited good dielectric properties.

[0074] Furthermore, the various numerical ranges described in this specification can be any combination of their upper and lower limits, and all such combinations are described herein as preferred numerical ranges. Also, the description of a numerical range as "X to Y" means X or greater and Y or less.

[0075] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their omissions, substitutions, and modifications are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

Claims

1. A divinylbenzylfluorene compound represented by the following general formula (1), R in general formula (1) １ , R ２ and R ３ A divinylbenzylfluorene compound in which each of the following groups independently represents a hydrocarbon group having 1 to 5 carbon atoms, a, b, and c independently represent an integer from 0 to 4, and the ratio of p,p-isomers, in which both vinylbenzyl groups in general formula (1) are para isomers, is 20 to 50%.

2. The divinylbenzylfluorene compound according to claim 1, wherein the solubility in methyl ethyl ketone at 22°C is 20% by mass or more.

3. The divinylbenzylfluorene compound according to claim 1, wherein the melting point is higher than 130°C and 200°C or lower.

4. A curable resin composition comprising the divinylbenzylfluorene compound described in claim 1.

5. A cured product obtained by curing a divinylbenzylfluorene compound according to any one of claims 1 to 3, or a curable resin composition according to claim 4.

6. The method involves reacting a fluorene compound represented by the following general formula (2) with a vinyl benzyl halide compound represented by the following general formula (3) having a meta / para molar ratio of 30 / 70 to 60 / 40 in an aprotic polar solvent with a boiling point of less than 100°C in the presence of an alkali, and precipitating the resulting product in a mixed solvent of a carbon-1 to carbon-4 alcohol and water. R in general formula (2) １ and R ２ Each of the following independently represents a hydrocarbon group having 1 to 5 carbon atoms, and each of the following independently represents an integer from 0 to 4: R in general formula (3) ３ A method for producing a divinylbenzylfluorene compound, wherein represents a hydrocarbon group having 1 to 5 carbon atoms, c represents an integer from 0 to 4, and X represents a halogen atom.

7. A method for producing a divinylbenzylfluorene compound according to claim 6, further comprising washing the product obtained by the above reaction with water, and performing the above precipitation after washing with water.

8. The method for producing a divinylbenzylfluorene compound according to claim 6 or 7, wherein the aprotic polar solvent is methyl ethyl ketone.

9. The method for producing a divinylbenzylfluorene compound according to claim 6 or 7, wherein the amount of water in the mixed solvent is 20 to 40% by mass.

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