Epoxy resin composition

Abstract

The present invention is an epoxy resin composition containing (A) an epoxy resin containing two or more epoxy groups in one molecule, (B) a mesogenic group-containing polyorganosiloxane represented by formula (1), and (C) an epoxy resin curing agent. An epoxy resin composition including a polyorganosiloxane having a mesogenic group may be provided. In formula (1), R1 each independently represents a hydroxyl group or a group selected from the group consisting of an alkyl group having 1-12 carbon atoms, an aryl group having 6-12 carbon atoms, and an aralkyl group having 7-12 carbon atoms, p is an integer of 0-100, R2 each independently represents formula (2) or formula (3), in formula (2) and formula (3), R3 and R4 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1-10 carbon atoms, L is a divalent hydrocarbon group having 1-12 carbon atoms, and n is an integer of 1-10. A and b are integers from 0 to 4, and G is glycidyl. # imgabs0 # # imgabs1 # # imgabs2 #

Description

Technical Field

[0001] The invention relates to an epoxy resin composition. Background Art

[0002] Epoxy resins are used in various fields due to their excellent physical strength, electrical insulation, heat resistance, chemical resistance, water resistance, low shrinkage, and adhesiveness. In recent years, the performance requirements of epoxy resins have increased, and the technical problem of low toughness of epoxy resins has been developed (Patent Documents 1 to 4).

[0003] Epoxy-modified silicone is a polyorganosiloxane having an epoxy group as a reactive group, and is used in applications such as resin modifiers, fiber treatment agents, and coating additives that utilize its reactivity. In addition, although the effect of imparting flexibility as a characteristic of silicone can be expected, when epoxy-modified silicone is added to epoxy resin, there is a technical problem that it has poor compatibility with other polar compounds such as curing agents and separates.

[0004] Patent Document 5 describes an epoxy resin having a mesogenic group and reports that the epoxy resin has excellent handleability and excellent physical, thermodynamic and chemical properties. However, it is not clear how the properties of the epoxy resin change when the epoxy resin having a mesogenic group is mixed with a common epoxy resin such as a bisphenol epoxy resin.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2008-239890

[0008] Patent Document 2: Japanese Patent Application No. 2014-505761

[0009] Patent Document 3: Japanese Patent Application No. 2017-536440

[0010] Patent Document 4: International Publication No. 2018 / 008741

[0011] Patent Document 5: Japanese Patent Application Publication No. 2008-214599 Summary of the invention

[0012] 1. Technical issues to be resolved

[0013] The effect when adding epoxy resins with mesogenic groups has not been studied in detail.

[0014] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an epoxy resin composition containing a polyorganosiloxane having a mesogenic group.

[0015] (II) Technical solution

[0016] In order to solve the above technical problems, the present invention provides an epoxy resin composition comprising:

[0017] 100 parts by mass of (A) an epoxy resin having two or more epoxy groups in one molecule,

[0018] 5 to 20 parts by mass of (B) a mesogenic group-containing polyorganosiloxane represented by the following formula (1),

[0019] 1 to 20 parts by weight of (C) an epoxy resin curing agent.

[0020] [Chemical formula 1]

[0021]

[0022] In the formula (1), R 1 each independently represents a group selected from an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms, or a hydroxyl group; p represents a repeating unit of a siloxane structure and is an integer of 0 to 100; R 2 Independently of each other, they represent the following formula (2) or formula (3),

[0023] [Chemical formula 2]

[0024]

[0025] [Chemical formula 3]

[0026]

[0027] In the above formula (2) and the above formula (3), R 3 and R 4 Each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, L is a connecting group to the formula (1) and is a divalent hydrocarbon group having 1 to 12 carbon atoms, a and b represent the number of substituents of the phenyl group in the formula (2) and the formula (3) and are integers of 0 to 4, and G is a glycidyl group.

[0028] Such an epoxy resin composition, when made into a cured product, is excellent in tensile shear strength and elongation at break.

[0029] Furthermore, in the present invention, it is preferred that the mesogenic group-containing polyorganosiloxane represented by the formula (1) has a number average molecular weight of 500 to 100,000 in terms of polystyrene standard substance.

[0030] Such a molecular weight is a molecular weight sufficient to allow the epoxy groups at both terminals to react with the curing agent to obtain a cured product.

[0031] Furthermore, in the present invention, it is preferred that the epoxy equivalent (g / mol) of the mesogenic group-containing polyorganosiloxane represented by the formula (1) is 300 to 5,000 g / mol.

[0032] Such an epoxy equivalent is an amount sufficient to allow the epoxy groups at both terminals to react with the (C) epoxy resin curing agent to obtain a cured product with good physical properties.

[0033] Furthermore, in the present invention, it is preferred that the mesogenic group-containing polyorganosiloxane represented by the formula (1) contains 3,000 ppm or less of hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) in total.

[0034] By reducing the amount of these cyclic low-molecular siloxanes, it is possible to avoid a decrease in adhesion due to the bleeding of low-molecular components onto the surface of the cured product, and to avoid contamination of the surrounding environment due to the volatilization of low-molecular components.

[0035] Furthermore, in the present invention, it is preferred that the (A) epoxy resin is a bisphenol epoxy resin.

[0036] Such an epoxy resin composition can enhance the properties of the bisphenol-type epoxy resin used through various selections, and can increase both tensile properties and tensile shear strength compared to the case of using the bisphenol-type epoxy resin alone.

[0037] Furthermore, in the present invention, it is preferred that the (C) epoxy resin curing agent is an amine curing agent.

[0038] With such an epoxy resin composition, good curing characteristics can be obtained.

[0039] Furthermore, in the present invention, it is preferred that (D) a filler is further contained.

[0040] Such an epoxy resin composition can enhance physical strength.

[0041] (III) Beneficial effects

[0042] The present invention relates to an epoxy resin composition containing a polyorganosiloxane, and a cured product obtained by reacting and curing the composition, and more specifically, to an epoxy resin composition having epoxy groups at both ends and containing a polyorganosiloxane having a mesogen group in the main chain, and a cured product obtained by reacting and curing the composition.

[0043] The epoxy resin composition of the present invention has improved toughness when formed into a cured product by being blended with a predetermined structure, and exhibits good adhesive strength when formed into a cured product between substrates, and thus has high usefulness. DETAILED DESCRIPTION

[0044] As described above, there is a demand for the development of an epoxy resin composition containing a polyorganosiloxane having a mesogenic group.

[0045] The inventors of the present application have conducted intensive studies on the above-mentioned technical problems and have found that an epoxy resin composition blended with a specified structure has improved toughness when formed into a cured product and exhibits good adhesion when formed into a cured product between substrates, and is therefore highly useful, thereby completing the present invention.

[0046] That is, the present invention is an epoxy resin composition comprising

[0047] 100 parts by mass of (A) an epoxy resin having two or more epoxy groups in one molecule,

[0048] 5 to 20 parts by mass of (B) a mesogenic group-containing polyorganosiloxane represented by the following formula (1),

[0049] 1 to 20 parts by weight of (C) an epoxy resin curing agent.

[0050] [Chemical formula 4]

[0051]

[0052] In the formula (1), R 1 each independently represents a group selected from an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms, or a hydroxyl group; p represents a repeating unit of a siloxane structure and is an integer of 0 to 100; R 2 Independently of each other, they represent the following formula (2) or formula (3),

[0053] [Chemical formula 5]

[0054]

[0055] [Chemical formula 6]

[0056]

[0057] In the above formula (2) and the above formula (3), R 3 and R 4Each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, L is a connecting group to the formula (1) and is a divalent hydrocarbon group having 1 to 12 carbon atoms, a and b represent the number of substituents of the phenyl group in the formula (2) and the formula (3) and are integers of 0 to 4, and G is a glycidyl group.

[0058] [Epoxy resin composition]

[0059] The epoxy resin composition of the present invention comprises (A) an epoxy resin, (B) a mesogenic group-containing polyorganosiloxane and (C) an epoxy resin curing agent, wherein the component (B) is 5 to 20 parts by mass based on 100 parts by mass of the component (A).

[0060] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0061] [(A) Epoxy resin]

[0062] The epoxy resin (A) of the present invention includes two or more epoxy groups in one molecule. Known epoxy resins can be used, and there is no particular limitation. For example, bisphenol-type epoxy resins such as bisphenol A epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin can be listed, alicyclic epoxy resins such as dicyclopentadiene epoxy resin, 3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexene carboxylate, multifunctional phenol-type epoxy resins such as resorcinol epoxy resin, stilbene epoxy resin, epoxy resin containing triazine skeleton, epoxy resin containing fluorene skeleton, trisphenol alkane type epoxy resin, biphenyl type epoxy resin, xylene type epoxy resin, biphenyl aralkyl type epoxy resin, naphthalene type epoxy resin and diglycidyl ether compounds of polycyclic aromatics such as anthracene can be used alone. These epoxy resins can be used alone or in combination. Preferably, bisphenol-type epoxy resin.

[0063] The epoxy equivalent of the epoxy resin (A) is not particularly limited, but is preferably 50 to 5,000 g / eq, more preferably 75 to 2,500 g / eq, per unit solid content, from the viewpoint of usable time after mixing and strength of a cured product.

[0064] The properties of the (A) epoxy resin are not particularly limited, but it is preferably liquid at 25° C. When it is liquid, its viscosity is preferably 10 to 100,000 mPa·s, more preferably 20 to 50,000 mPa·s. The viscosity is a value measured at 25° C. using a B-type viscometer described in JIS K7117-1:1999.

[0065] In addition, as is clear from the above examples, the component (A) of the present invention does not have an organosiloxy group in the molecule. This point is different from the component (B) described below.

[0066] [(B) Mesogen Group-Containing Polyorganosiloxane]

[0067] The component (B) of the present invention is a mesogenic group-containing polyorganosiloxane represented by the following formula (1).

[0068] [Chemical formula 7]

[0069]

[0070] In the formula (1), R 1 each independently represents a group selected from an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms, or a hydroxyl group; p represents a repeating unit of a siloxane structure and is an integer of 0 to 100; R 2 Each independently represents the following formula (2) or formula (3).

[0071] In formula (1), R 1 Independently of each other, there can be mentioned a group selected from an alkyl group having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, an aryl group having 6 to 12 carbon atoms, preferably 6 to 9 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms, preferably 7 to 10 carbon atoms, or a hydroxyl group. Specific examples thereof include straight-chain or branched-chain alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl, cycloalkyl groups such as cyclohexyl, aryl groups such as phenyl and naphthyl, and aralkyl groups such as benzyl. Among them, methyl or phenyl is preferred.

[0072] p represents a repeating unit of a siloxane structure and is an integer of 0 to 100, preferably 0 to 40, more preferably 0 to 10, and particularly preferably p=1.

[0073] In formula (1), R 2 They are independently of each other represented by the following formula (2) or (3).

[0074] [Chemical formula 8]

[0075]

[0076] [Chemical formula 9]

[0077]

[0078] In the above formula (2) and the above formula (3), R 3 and R 4Each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, L is a connecting group to the formula (1) and is a divalent hydrocarbon group having 1 to 12 carbon atoms, a and b represent the number of substituents of the phenyl group in the formula (2) and the formula (3) and are integers of 0 to 4, and G is a glycidyl group.

[0079] In formulas (2) and (3), R 3 and R 4 Each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms.

[0080] The monovalent hydrocarbon group having 1 to 10 carbon atoms is a group selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms, and specific examples thereof include the aforementioned groups.

[0081] a and b represent the number of substituents of the phenyl group in formula (2) and (3), and represent an integer of 0 to 4.

[0082] G in formula (2) and (3) is a glycidyl group (2,3-epoxypropyl group).

[0083] L in formula (2) and (3) is a linking group to formula (1), and is a divalent hydrocarbon group having 1 to 12 carbon atoms.

[0084] Examples of the divalent hydrocarbon group include an alkylene group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms, and an aralkylene group having 7 to 12 carbon atoms.

[0085] The alkylene group having 1 to 12 carbon atoms may be any of a linear, branched or cyclic group, and specific examples thereof include linear or branched alkylene groups such as n-pentenyl, n-hexenyl, n-heptenyl, n-octenyl, 2-ethylhexenyl, n-decenyl, n-undecenyl and n-dodecenyl.

[0086] Furthermore, the alkylene group may have one or more ether bonds in the middle of the molecular chain. Specifically, it is a group containing an ether bond, such as an ethoxy group, a propoxy group, or a butoxy group, and the ether bonds may be multiple.

[0087] Examples of the aromatic hydrocarbon group having 6 to 12 carbon atoms include o-phenylene, m-phenylene, p-phenylene, 3,5-benzylidene, 2,4-benzylidene, 2,6-benzylidene, 1,2-naphthylene, 1,8-naphthylene, 2,3-naphthylene and 4,4′-biphenylene.

[0088] Examples of the aralkylene group having 7 to 12 carbon atoms include o-xylylene, m-xylylene, and p-xylylene.

[0089] In the above formula (1), R2 The following formula (4) is more preferred.

[0090] [Chemical formula 10]

[0091]

[0092] In formula (4), c represents the number of carbon atoms of the connecting group to the siloxane skeleton, which is an integer of 0 to 6, and the dotted line represents the connecting position to formula (1). 3 , R 4 , a and b and the aforementioned R 3 , R 4 , a and b are the same.

[0093] c represents the number of carbon atoms of the group connecting to the siloxane skeleton in formula (4), and is an integer of 0 to 6, and preferably c=1.

[0094] The dotted line indicates the connection position with formula (1).

[0095] The number average molecular weight of the mesogen group-containing polyorganosiloxane (B) in the present invention is preferably 500 to 100,000, more preferably 500 to 50,000, and further preferably 500 to 20,000. Within this range, the molecular weight is sufficient to allow the epoxy groups at both ends to react with the curing agent and obtain a cured product. In addition, the number average molecular weight refers to the number average molecular weight calculated based on polystyrene standard substances in the gel permeation chromatography (GPC) measurement under the following measurement conditions.

[0096] [Measurement conditions]

[0097] Elution solvent: tetrahydrofuran (THF)

[0098] Flow rate: 0.6mL / min

[0099] Detector: Differential refractive index detector (RI)

[0100] Column: TSK Guardcolumn SuperH-H

[0101] TSKgel SuperHM-N(6.0mmI.D.×15cm×1)

[0102] TSKgel SuperH2500(6.0mmI.D.×15cm×1)

[0103] (Both manufactured by TOSOH CORPORATION)

[0104] Column temperature: 40°C

[0105] Sample injection volume: 50 μL (0.3 mass % THF solution)

[0106] The epoxy equivalent (g / mol) of the mesogenic group-containing polyorganosiloxane (B) in the present invention is preferably 300 to 5,000 g / mol, and more preferably 400 to 2,500 g / mol. If it is within this range, it is an amount sufficient to react the epoxy groups at both ends with the epoxy resin curing agent (C) described later and obtain a cured product with good physical properties. The epoxy equivalent (g / mol) can be calculated by adding hydrochloric acid to a sample of a specified mass dissolved in 1,4-dioxane, and performing back titration using an aqueous sodium hydroxide solution.

[0107] As described in International Publication No. 2016 / 111104, etc., low molecular weight cyclic siloxanes may cause various adverse conditions, and are preferably reduced. In component (B), a polyorganosiloxane containing hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) in a total amount of preferably more than 0 ppm and 3,000 ppm or less, more preferably 0.1 to 2,000 ppm, and further preferably 0.1 to 1,000 ppm can be used.

[0108] The amount of the low molecular weight cyclic siloxanes (D3 to D6) is a value obtained by quantifying the amount of the component (B) by gas chromatography (GC) using a sample obtained by extracting and diluting the component (B) with an organic solvent. In addition, the term "more than 0 ppm" means that even a very small amount detected as a peak when quantified by the method described above is regarded as "more than 0 ppm".

[0109] [(C) Epoxy resin curing agent]

[0110] The epoxy resin curing agent (C) of the present invention can use a known curing agent that can react with the epoxy resin to cure it. The purpose of adding the curing agent is to react the reactive functional groups (amino, phenolic hydroxyl, acid anhydride, mercapto, etc.) in the molecules of the curing agent with the epoxy groups in the components (A) and (B) to form a cured product with a three-dimensional crosslinked structure.

[0111] (C) As a component, an amine type curing agent, a phenol type curing agent, an acid anhydride type curing agent, a thiol type curing agent etc. are mentioned, for example.

[0112] Among them, amine curing agents are preferred, and examples of amine curing agents include aromatic polyamines, aliphatic polyamines, polyamidoamines, polyether polyamines, etc. Aromatic polyamines are more preferred.

[0113] Examples of the aromatic polyamine include compounds represented by the following formulae (I) to (IV).

[0114] [Chemical formula 11]

[0115]

[0116] In formulas (I) to (IV), R is independently a hydrogen atom or a monovalent alkyl group having 1 to 6 carbon atoms, and R' is independently a hydrogen atom, a monovalent alkyl group having 1 to 12 carbon atoms, a phenyl group or an aminophenyl group, and two R' groups may be bonded to form a ring structure.

[0117] Specific examples of the aromatic polyamine include aromatic diaminodiphenylmethane compounds such as 4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetraethyl-4,4'-diaminodiphenylmethane, 2,4-diaminotoluene, 1,4-diaminobenzene, 1,3-diaminobenzene, etc. These aromatic polyamines can be used alone or in combination of two or more.

[0118] In the present invention, when (A) component is set to 100 parts by mass, (B) component is 5 to 20 parts by mass, preferably 10 to 20 parts by mass, and (C) component is 1 to 20 parts by mass, preferably 1 to 10 parts by mass. If the mass parts of (B) component or (C) component exceed 20 parts by mass, the strength of the cured product of epoxy resin is reduced, and the adhesive force cannot be fully obtained. In addition, since Tg is reduced, the heat resistance is also reduced. If the mass parts of (B) component are less than 5 parts by mass, the desired effect of adding (B) component is reduced. If the mass parts of (C) component are less than 1 part by mass, the desired effect of adding (C) component is reduced.

[0119] [Other ingredients]

[0120] The epoxy resin composition of the present invention may further include (D) fillers. As fillers, for example, silicas such as fused silica, crystalline silica, cristobalite, metal oxides such as aluminum oxide, titanium oxide, and magnesium oxide, etc., can be listed, and one can be used alone, or two or more can be used simultaneously. Among them, from the perspective of ease of acquisition or stability of quality, silicas are preferred. The average particle size is preferably 0.1 to 50 μm, which can be selected according to the purpose. The average particle size is as long as the volume average particle size measured, for example, by a laser diffraction method.

[0121] The filler is preferably surface-treated in advance using a coupling agent such as a silane coupling agent. The amount of the coupling agent used for the surface treatment and the surface treatment method are not particularly limited.

[0122] The epoxy resin composition of the present invention may be added with other additives as needed according to the purpose of the present invention. Examples of the additives include reactive diluents, curing accelerators, flame retardants, ion trapping agents, antioxidants, adhesion promoters, colorants, coupling agents, and the like.

[0123] The preparation method of the epoxy resin composition of the present invention can be, for example, by heat-treating component (A), component (B) and component (C), while mixing, stirring, dissolving and dispersing, thereby obtaining a composition. In addition, component (A), component (B) or component (C) can be heat-treated, while mixing, stirring, dissolving and dispersing, thereby obtaining a composition. Preferably, component (B) and component (C) can be heat-treated, while mixing, stirring, dissolving and dispersing, and then adding component (A) to obtain a composition in which component (B) is well dispersed.

[0124] In addition, component (D) and / or other additives may be added as needed. They may be added to component (A), component (B) and component (C), while being heat treated simultaneously or separately, while being mixed, stirred, dissolved and dispersed. Alternatively, component (B) and component (C) may be heat treated, while being mixed, stirred, dissolved and dispersed, and then component (D) and / or other additives may be added simultaneously with component (A).

[0125] The curing conditions of the epoxy resin composition of the present invention are not particularly limited, and for example, heating at 60 to 200° C., preferably 80 to 180° C., for 30 minutes to 10 hours, preferably 1 to 5 hours may be sufficient. In addition, in order to efficiently react, for example, the above-mentioned time may be heated in 1 to 5 stages from a lower temperature to a higher temperature.

[0126] Example

[0127] Hereinafter, the present invention will be specifically described using Examples, Comparative Examples, and Synthesis Examples, but the present invention is not limited thereto.

[0128] Bisphenol A type epoxy resin: jER828EL manufactured by Mitsubishi Chemical Corporation

[0129] (Epoxy equivalent: 186 g / mol, viscosity: 13,000 mPa·s)

[0130] (Hereinafter, referred to as DGEBA.)

[0131] Amine curing agent: 4,4'-diaminodiphenylmethane (NH equivalent: 49.6 g / mol) manufactured by Tokyo Chemical Industry Co., Ltd. (hereinafter referred to as DDM.)

[0132] [Synthesis Example 1] Synthesis method of SM epoxy resin

[0133] 360 mL of ethanol, 17.9 g (0.164 mol) of p-aminophenol, 20 g (0.164 mol) of 4-allyloxybenzaldehyde and a small amount of zinc chloride were added to a glass reactor, and the mixture was reacted in an oil bath at 60° C. for 4 hours. The mixture was allowed to stand in a refrigerator for 2 hours, and the precipitated crystals were filtered to obtain 27 g of 4-((4-allyloxy)benzylideneamino)phenol.

[0134] Next, 7 g (0.033 mol) of the obtained 4-((4-allyloxy)benzylideneamino)phenol, 5 mL of dimethyl sulfoxide, 37 g of epichlorohydrin (0.394 mol), and a small amount of tetra-n-butylammonium chloride were added to a 500 ml separatory bottle, and reacted at 60° C. for 2 hours, and then 3.16 g (0.04 mol) of a 50% aqueous sodium hydroxide solution was added dropwise over 1 hour, and further reacted for 3 hours. The obtained solution was cooled, and the precipitated crystals were filtered, washed thoroughly with distilled water, and then dried to obtain 3.9 g of 4-((4-allyloxy)benzylideneamino)phenol glycidyl ether.

[0135] 2 g (6.5 mmol) of 4-((4-allyloxy)benzylideneamino)phenol glycidyl ether was placed in a separatory flask and dissolved in 40 mL of 1,4-dioxane. Further, 0.667 g (3.24 mmol) of 1,1,3,3,5,5-hexamethyltrisiloxane and 0.02 g (0.06 mmol) of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex were added. The temperature of the oil bath was raised to 90°C and the mixture was heated with stirring for 6 hours.

[0136] The reaction solution was cooled, the precipitated crystals were filtered, and washed thoroughly with methanol to obtain white crystals. The amount of low molecular weight cyclic siloxanes (D3 to D6) in the obtained SM epoxy resin was measured, and the results were all below the detection limit.

[0137] [Examples 1 to 3]

[0138] The defoamed DGEBA and the SM epoxy resin of Synthesis Example 1 were placed in an aluminum cup and heated on a hot plate at 130°C to reduce the viscosity. Next, a chemically equivalent amount of DDM was placed in another aluminum cup and stirred on a hot plate at the same temperature until it was completely dissolved. Then, the dissolved DDM was added to the aluminum cup containing DGEBA and the SM epoxy resin of Synthesis Example 1 and stirred for 5 minutes to prepare a composition.

[0139] Then, the aluminum cup containing the above composition was heat-cured in three steps: heat-cured at 120°C for 2 hours, heat-cured at 150°C for 2 hours, and heat-cured at 180°C for 2 hours. In addition, the heating rate was set to 5°C / min. The blending amount and the physical properties of the cured product are recorded in Table 1.

[0140] [Example 4]

[0141] The SM epoxy resin of Synthesis Example 1 and the dissolved DDM in a chemical equivalent relative to all epoxy groups were added to an aluminum cup and stirred on a hot plate at 140° C. for 15 minutes. Next, the defoamed DGEBA was placed in another aluminum cup and heated on a hot plate at 130° C. for the purpose of reducing the viscosity. Then, the DGEBA with reduced viscosity was added to the aluminum cup containing the SM epoxy resin of Synthesis Example 1 and DDM, and heated and stirred for 2 minutes to prepare a composition.

[0142] Then, the aluminum cup containing the above composition was heat-cured in three stages using a thermostatic bath, namely, heat-cured at 120°C for 2 hours, heat-cured at 150°C for 2 hours, and heat-cured at 180°C for 2 hours. In addition, the heating rate was set to 5°C / min. The blending amount and the physical properties of the cured product are recorded in Table 1.

[0143] [Comparative Example 1]

[0144] The defoamed DGEBA was placed in an aluminum cup and heated on a hot plate at 130°C to reduce viscosity. Next, a chemically equivalent amount of DDM was placed in another aluminum cup and stirred on a hot plate at the same temperature until it was completely dissolved. The dissolved DDM was then added to the aluminum cup containing DGEBA and stirred for 5 minutes to prepare a composition.

[0145] Then, the aluminum cup containing the above composition was heat-cured in three stages using a thermostatic bath at 120°C for 2 hours, 150°C for 2 hours, and 180°C for 2 hours. In addition, the heating rate was set to 5°C / min. The blending amount and the physical properties of the cured product are recorded in Table 1.

[0146] [Dynamic viscoelasticity measurement]

[0147] The cured products of Examples 1 to 4 and Comparative Example 1 were cut into test pieces with a length of 30 mm × a width of 4.0 mm × a thickness of 0.40 mm, and measured using Rheogel-E40000 manufactured by UBM CORPORATION under the conditions of a temperature range of -150 to 250°C, a sine wave, a heating rate of 2.5°C / min, a tensile mode, and a frequency of 10 Hz. For the obtained results, the peak value of the loss tangent tanδ, which is the loss modulus (G") / storage modulus (G'), was taken as Tg.

[0148] [Tensile test]

[0149] The cured products of Examples 1 to 4 and Comparative Example 1 were cut into test pieces with a length of 30 mm × a width of 2.0 mm × a thickness of 2.0 mm. The breaking strength and breaking elongation of the test pieces were measured using AGS-J manufactured by SHIMADZU CORPORATION at a die speed of 2 mm / min. The breaking strength and breaking elongation were set as the average values ​​of N=5.

[0150] [Table 1]

[0151]

[0152] [Examples 5 to 8, Comparative Example 2]

[0153] [Tensile shear adhesion test]

[0154] The mild steel plate was immersed in acetone and ultrasonically cleaned for 30 minutes. Next, the mild steel plate was ground using an electric sander equipped with #240 abrasive paper to remove the oxide film on the surface, immersed in acetone, and ultrasonically cleaned twice for 30 minutes. Then, a plate (length 25mm×width 25mm×thickness 1.6mm) was attached to the portion 62.5mm away from the end of the mild steel plate. Then, the composition prepared in each example was applied to 12.5mm away from the end of the mild steel plate, and another mild steel plate was superimposed, and heated at 120°C for 2 hours at 5MPa using a hot press. Then, a weight (weight: 1700g, pressure: 960Pa) was placed on the test piece in a constant temperature bath, and after heating at 150°C for 2 hours, the temperature was raised to 180°C at a heating rate of 5°C / min, and heated and cured at 180°C for 2 hours to prepare a test piece. After slowly cooling, the test piece was taken out, and the resin exposed from the joint was removed using a utility knife.

[0155] AGS-X manufactured by SHIMADZU CORPORATION was used to perform a tensile shear adhesion test on the obtained test piece by the method described in JIS K6850:1999 at a head speed of 50 mm / min. The tensile shear strength and elongation at break were set to an average value of N=5. The failure morphology was confirmed by the naked eye. The composition used in the evaluation and the results of the tensile shear adhesion test are recorded in Table 2.

[0156] [Table 2]

[0157]

[0158] In Examples 5 to 8, the cured products formed from the epoxy resin compositions of the present invention showed increases in tensile shear strength and elongation at break based on the tensile shear adhesion test compared to Comparative Example 2, demonstrating the usefulness of the epoxy resin compositions of the present invention.

[0159] This manual contains the following protocols.

[0160] [1]: An epoxy resin composition, characterized in that it comprises:

[0161] 100 parts by mass of (A) an epoxy resin having two or more epoxy groups in one molecule,

[0162] 5 to 20 parts by mass of (B) a mesogenic group-containing polyorganosiloxane represented by the following formula (1),

[0163] 1 to 20 parts by weight of (C) epoxy resin curing agent,

[0164] [Chemical formula 12]

[0165]

[0166] In the formula (1), R 1 each independently represents a group selected from an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms, or a hydroxyl group; p represents a repeating unit of a siloxane structure and is an integer of 0 to 100; R 2 Independently of each other, they represent the following formula (2) or formula (3),

[0167] [Chemical formula 13]

[0168]

[0169] [Chemical formula 14]

[0170]

[0171] In the above formula (2) and the above formula (3), R 3 and R 4 Each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, L is a connecting group to the formula (1) and is a divalent hydrocarbon group having 1 to 12 carbon atoms, a and b represent the number of substituents of the phenyl group in the formula (2) and the formula (3) and are integers of 0 to 4, and G is a glycidyl group.

[0172] [2]: The epoxy resin composition according to [1] above, wherein the mesogenic group-containing polyorganosiloxane represented by the formula (1) has a number average molecular weight of 500 to 100,000 in terms of polystyrene standard substance.

[0173] [3]: The epoxy resin composition according to [1] or [2], characterized in that the epoxy equivalent (g / mol) of the mesogenic group-containing polysiloxane represented by the formula (1) is 300 to 5,000 g / mol.

[0174] [4]: The epoxy resin composition according to [1], [2] or [3], characterized in that the mesogenic group-containing polysiloxane represented by the formula (1) contains hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) in a total amount of 3,000 ppm or less.

[0175] [5]: The epoxy resin composition according to [1], [2], [3] or [4], wherein the epoxy resin (A) is a bisphenol-type epoxy resin.

[0176] [6]: The epoxy resin composition according to [1], [2], [3], [4] or [5] above, characterized in that the (C) epoxy resin curing agent is an amine curing agent.

[0177] [7]: The epoxy resin composition according to [1], [2], [3], [4], [5] or [6], further comprising (D) a filler.

[0178] The present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any technical solution having substantially the same configuration and having the same function and effect as the technical concept described in the claims of the present invention is included in the technical scope of the present invention.

Claims

1. An epoxy resin composition, characterized in that It contains: 100 parts by mass of (A) an epoxy resin having two or more epoxy groups in one molecule, 5 to 20 parts by mass of (B) a mesogenic group-containing polyorganosiloxane represented by the following formula (1), 1 to 20 parts by weight of (C) epoxy resin curing agent, [Chemical formula 1] In the formula (1), R 1 each independently represents a group selected from an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms, or a hydroxyl group; p represents a repeating unit of a siloxane structure and is an integer of 0 to 100; R 2 Independently of each other, they represent the following formula (2) or formula (3), [Chemical formula 2] [Chemical formula 3] In the above formula (2) and the above formula (3), R 3 and R 4 Each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, L is a connecting group to the formula (1) and is a divalent hydrocarbon group having 1 to 12 carbon atoms, a and b represent the number of substituents of the phenyl group in the formula (2) and the formula (3) and are integers of 0 to 4, and G is a glycidyl group.

2. The epoxy resin composition according to claim 1, characterized in that The number average molecular weight of the mesogen group-containing polyorganosiloxane represented by the formula (1) is 500 to 100,000 in terms of polystyrene standard substance.

3. The epoxy resin composition according to claim 1, characterized in that The epoxy equivalent (g / mol) of the mesogenic group-containing polyorganosiloxane represented by the formula (1) is 300 to 5,000 g / mol.

4. The epoxy resin composition according to claim 1, characterized in that The mesogenic group-containing polyorganosiloxane represented by the formula (1) contains 3,000 ppm or less of hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) in total.

5. The epoxy resin composition according to claim 1, characterized in that The (A) epoxy resin is a bisphenol epoxy resin.

6. The epoxy resin composition according to claim 1, characterized in that The (C) epoxy resin curing agent is an amine curing agent.

7. The epoxy resin composition according to any one of claims 1 to 6, characterized in that It further comprises (D) a filler.

Images