Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
  • C08G59/02—Polycondensates containing more than one epoxy group per molecule
  • C08G59/04—Polycondensates containing more than one epoxy group per molecule of polyhydroxy compounds with epihalohydrins or precursors thereof
  • C08G59/06—Polycondensates containing more than one epoxy group per molecule of polyhydroxy compounds with epihalohydrins or precursors thereof of polyhydric phenols
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
  • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
  • C08G59/20—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the epoxy compounds used
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L71/00—Compositions of polyethers obtained by reactions forming an ether link in the main chain; Compositions of derivatives of such polymers
  • C08L71/08—Polyethers derived from hydroxy compounds or from their metallic derivatives
  • C08L71/10—Polyethers derived from hydroxy compounds or from their metallic derivatives from phenols
  • C08L71/12—Polyphenylene oxides

Definitions

• the present invention relates to an epoxy resin composition used in the field of electronic materials, a resin sheet and a cured product using the epoxy resin composition, and a phenoxy resin used in the epoxy resin composition.
• Epoxy resins are widely used in electronic parts, electrical equipment, automobile parts, FRP, sports equipment and the like because they are excellent in adhesiveness, heat resistance and moldability. In particular, in recent years, it is one of materials that have attracted much attention in the field of electronic materials (for example, Non-Patent Document 1).
• an epoxy resin composition containing an epoxy resin monomer having a biphenyl group or a biphenyl derivative, a dihydric or higher phenol having a hydroxyl group disposed at least in the ortho position, and a curing accelerator has also been proposed (for example, Patent Document 1).
• the cured product using this epoxy resin composition has improved thermal conductivity, but no specific solution has been shown for the problem of crystal precipitation in the varnish state.
• an object of the present invention is to provide a resin composition having no thermal precipitation in the state of varnish dissolved in a solvent and having excellent thermal conductivity in the state of a cured product.
• the present inventors have intensively studied to increase the solubility of the epoxy resin in a varnish state, and as a result, by adding an amorphous phenoxy resin having a specific structure to the epoxy resin.
• the inventors have found that the precipitation of epoxy resin crystals in the varnish can be prevented.
• the above amorphous phenoxy resin has a highly symmetrical structure, it becomes a uniform resin solution without precipitating crystals in the varnish. It has also been found that phenoxy resin exhibits higher thermal conductivity than general-purpose phenoxy resin.
• the epoxy resin composition of the present invention comprises the following components (a) to (c): (A) epoxy resin, (B) a curing agent, and (c) an amorphous phenoxy resin having a weight average molecular weight represented by the following general formula (1) in the range of 10,000 to 200,000, Is an epoxy resin composition containing
• the component (a) contains a crystalline epoxy resin having a mesogenic group within a range of 5 to 100% by weight based on the total amount of the component (a).
• Component) is contained within a range of 5 to 90 parts by weight with respect to 100 parts by weight of the total solid content in the components (a) and (c).
• X means a biphenylene skeleton represented by the following formula (2) or a naphthalene skeleton represented by the following formula (3)
• Y represents a biphenylene represented by the following formula (2)
• Z means a hydrogen atom or a glycidyl group
• n means a number representing a repeating unit.
• R 1 to R 8 each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.
• the mesogenic group may be a biphenylene group.
• the mesogenic group may be a naphthalene group.
• the component (c) may be an amorphous phenoxy resin in which X and Y in the formula (1) have a biphenylene skeleton represented by the formula (2). .
• At least four of R 1 to R 8 in the formula (2) may be an alkyl group having 4 or less carbon atoms, and the rest May be a biphenylene skeleton in which is a hydrogen atom.
• Y may be an unsubstituted biphenylene skeleton in which all of R 1 to R 8 in the formula (2) are hydrogen atoms.
• X may be a tetraalkylbiphenylene group in which an alkyl group having 4 or less carbon atoms is substituted at the 3,3′-position and the 5,5′-position.
• Y may be an unsubstituted biphenylene group.
• the component (c) may be an amorphous phenoxy resin having a naphthalene skeleton in which X is represented by the formula (3) in the formula (1).
• X may be a naphthalene skeleton having a single bond at each of the 1-position and the 6-position, and Y is R 1 to R 1 in the formula (2).
• An unsubstituted biphenylene skeleton in which all of R 8 are hydrogen atoms may be used.
• the epoxy resin composition of the present invention further comprises the following components (d), (D) inorganic filler, May be contained.
• the epoxy resin composition of the present invention further comprises the following components (e), (E) solvent, May be contained.
• the resin sheet of the present invention is obtained by forming any of the above epoxy resin compositions into a film.
• the cured product of the present invention is obtained by curing any of the above epoxy resin compositions.
• the phenoxy resin of the present invention has a tetramethylbiphenylene group substituted with a methyl group at the 3,3′-position and the 5,5′-position, and an unsubstituted biphenylene group, and has a weight average molecular weight of 10,000 to 200,000. Is within the range.
• the molar ratio of the tetramethylbiphenylene group substituted with a methyl group at the 3,3′-position and the 5,5′-position to the unsubstituted biphenylene group may be approximately 1: 1.
• the epoxy resin composition of the present invention comprises a combination of a crystalline epoxy resin having a mesogenic group and an amorphous phenoxy resin represented by the formula (1), so that the epoxy resin is solubilized in a solvent and varnished. It is possible to impart excellent thermal conductivity to the cured product while preventing precipitation of crystals therein. That is, by blending the amorphous phenoxy resin represented by the formula (1), the crystalline epoxy resin having a mesogenic group is solubilized, and a uniform resin composition can be obtained in a varnish state. Further, by applying and drying, molding into a resin sheet or the like can be easily performed. Moreover, the hardened
• the epoxy resin composition of the present invention can provide molded products and cured products such as a curable resin sheet, a curable high heat dissipation resin sheet, an insulating sheet, a prepreg, and an adhesive film excellent in thermal conductivity.
• the epoxy resin composition of the present embodiment contains the above components (A) to (C). Hereinafter, each component will be described.
• Epoxy resin for example, biphenyl type epoxy resin, naphthalene type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, o-cresol novolak Exemplified epoxy resins with two or more epoxy groups in the molecule such as epoxy resin, biphenyl novolac epoxy resin, triphenylmethane epoxy resin, dicyclopentadiene epoxy resin, alicyclic epoxy resin, brominated epoxy resin can do. These epoxy resins can be used alone or in combination of two or more.
• the component (a) preferably contains a crystalline epoxy resin having a mesogenic group within a range of 5 to 100% by weight with respect to the total amount of the component (a).
• the crystalline epoxy resin having a mesogenic group is a solid epoxy resin having a softening point of 40 ° C. or higher.
• the mesogenic group for example, a biphenylene group or a naphthalene group is preferable.
• the biphenyl type epoxy resin and the naphthalene type epoxy resin are preferable as the crystalline epoxy resin having a mesogenic group.
• the crystallinity means that an endothermic peak temperature based on the melting point can be confirmed in DSC (differential scanning calorimetry).
• Specific examples of crystalline epoxy resins having mesogenic groups include Nippon Steel & Sumikin Chemical Co., Ltd.
• GK-3007 (biphenol aralkyl type epoxy resin), Mitsubishi Chemical Corporation YX-4000 (tetramethylbiphenol type epoxy resin), Mitsubishi Chemical Examples include YL-6121H manufactured by Nippon Kayaku Co., Ltd., NC-3000 (biphenylene aralkylphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd., EPPN-501H (triphenylmethane type epoxy resin) manufactured by Nippon Kayaku Co., Ltd., and the like.
• the content of the component (a) epoxy resin is preferably within the range of 10 to 95 parts by weight, for example, with respect to 100 parts by weight of the total solids in the components (a) and (c), and 30 to 90 parts. More preferably within the range of parts by weight.
• the content of the epoxy resin as the component (a) is more than 95 parts by weight with respect to 100 parts by weight of the solid content, the workability of the epoxy resin composition in the B-stage state is deteriorated or the cured product becomes brittle. In some cases, the adhesive strength, heat resistance, temperature cycle resistance, etc. may decrease.
• the component (a) is a crystalline epoxy resin and the above upper limit is exceeded, the solvent solubility is lowered, and it becomes difficult to form a film of the epoxy resin composition.
• the content of the epoxy resin of component (a) is less than 10 parts by weight with respect to 100 parts by weight of the solid content, the epoxy resin composition is insufficiently cured, resulting in a decrease in adhesive strength and a decrease in heat resistance. May occur.
• the component (b) is a crystalline epoxy resin, if the component is below the lower limit, the resin sheet in the B-stage state becomes hard and easily broken.
• the solid content in the components (A) and (C) is, for example, when the epoxy resin composition is a varnish containing a predetermined solvent, and uses this varnish to form a cured product such as an insulating adhesive layer.
• the solid content in the components (a) and (c) that remains after the solvent is removed by drying or curing is meant.
• the varnish is a solvent containing a solvent for the purpose of reducing the viscosity of the epoxy resin composition and improving the workability. By doing so, a B-stage resin sheet can be obtained. Moreover, after impregnating the obtained varnish in a glass cloth etc., it can obtain a prepreg by drying. The solvent is removed by these drying steps.
• the content rate of the component in the epoxy resin composition of this Embodiment was prescribed
• ⁇ (B) component curing agent>
• the component (b) curing agent is blended for the purpose of curing the epoxy resin.
• an insulating layer an adhesive layer or a resin film is produced from the epoxy resin composition, sufficient insulation and adhesion are obtained. , Impart heat resistance, mechanical strength, etc.
• an imidazole curing agent or a non-imidazole curing agent can be used as the (b) component curing agent used in the present embodiment.
• the imidazole curing agent is preferably composed only of an imidazole compound.
• the imidazole-based curing agent can suppress the increase in viscosity of the epoxy resin composition, and the handling of the epoxy resin composition after blending becomes relatively easy.
• Examples of the imidazole compound include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-methyl-2-phenylimidazole, and 2-phenyl. Examples include -4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole.
• 2-phenyl-4,5-dihydroxymethylimidazole is most preferably used.
• 2-Phenyl-4,5-dihydroxymethylimidazole is a high-potency curing agent, and does not proceed with the curing reaction in the drying process when preparing a B-stage resin sheet, and is stable during long-term storage. Has excellent characteristics.
• the imidazole compound is usually often blended as a curing accelerator in a resin composition mainly composed of an epoxy resin.
• a resin composition mainly composed of an epoxy resin.
• the epoxy resin composition of the present embodiment when an imidazole-based curing agent is used, since no curing agent component other than the imidazole compound is used, the epoxy resin composition is subjected to anionic polymerization that proceeds from the imidazole compound. Can be cured. From such reaction characteristics, in the epoxy resin composition of the present embodiment, the imidazole compound can function as a curing agent, and compared with a reaction system in which an addition type curing agent component is blended, the blending as a curing agent. The amount can be kept low.
• the imidazole compound is a catalyst type curing agent, for example, if an addition type curing agent component such as dicyandiamide or a novolac type phenol resin is present, the addition type curing agent component and the epoxy resin react preferentially. However, the condensation reaction with the epoxy resin alone is unlikely to occur.
• an addition type curing agent component such as dicyandiamide or a novolac type phenol resin
• the content when using an imidazole-based curing agent comprising an imidazole compound as the component (b) is, for example, 0.01 to 10 parts by weight relative to a total of 100 parts by weight of the solid content in the components (a) to (c). Is preferably within the range of 0.01 to 5 parts by weight.
• the content of the imidazole curing agent is more than 10 parts by weight, there is a risk of inducing a halogen element derived from the epoxy resin as a halogen ion.
• the content of the imidazole-based curing agent is less than 0.01 parts by weight, the curing reaction does not proceed sufficiently, the adhesive strength is reduced, or the curing time is prolonged and the usability is reduced. There is.
• non-imidazole curing agent examples include those known as epoxy resin curing agents such as novolak-type phenol resin, dicyandiamide, diaminodiphenylmethane, and diaminodiphenylsulfone.
• the non-imidazole curing agent is preferably blended so that the equivalent ratio ((b) / (b)) to the epoxy resin of component (b) is 0.5 to 1.5.
• the range when using a phenol resin-based curing agent, the range is preferably 0.8 to 1.2, and when using an amine-based curing agent, the range is preferably 0.5 to 1.0.
• a curing accelerator in addition to the components (a) to (c).
• a curing accelerator for example, organophosphorus compounds such as triphenylphosphine, imidazoles such as 2-phenylimidazole and 2-ethyl-4-methylimidazole, and the like can be used.
• the blending ratio is appropriately selected according to the required curing time, but is generally 0.01 to 3.0 with respect to 100 parts by weight of the total solids in the components (a) to (c). Within the range of parts by weight is preferred.
• the amorphous phenoxy resin as the component (c) has a biphenylene skeleton or a naphthalene skeleton.
• Amorphous phenoxy resin prevents precipitation of crystals when the epoxy resin composition is in a varnish state and maintains a dissolved state in an organic solvent, and from the epoxy resin composition to an insulating layer, an adhesive layer, and a resin film. It is a component which improves the flexibility at the time of producing.
• the amorphous phenoxy resin having a biphenylene skeleton or a naphthalene skeleton is represented, for example, by the following general formula (1).
• X means a biphenylene skeleton represented by the following formula (2) or a naphthalene skeleton represented by the following formula (3)
• Y represents a biphenylene skeleton represented by the following formula (2).
• Z represents a hydrogen atom or a glycidyl group, and n represents a number representing a repeating unit.
• R 1 to R 8 each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.
• the ratio of X and Y is about 1: 1, but there may be a slight difference in the contents of X and Y.
• the molecular weight of the component (c) amorphous phenoxy resin is designed by the molar ratio of the starting compounds, and the desired product is generally obtained while controlling the reaction temperature and reaction time. It can be designed so that the end of the main chain is an epoxy group or a phenolic hydroxyl group depending on the molar ratio of the raw materials used.
• the non-crystalline phenoxy resin represented by the general formula (1) is substantially the same compound as the epoxy resin, but is called because it has different properties due to a difference in molecular weight. That is, the epoxy resin refers to those having a small molecular weight, and the phenoxy resin refers to those having a large molecular weight. Although there is no clear boundary, generally those having a weight average molecular weight of 10,000 or more are called phenoxy resins.
• the phenoxy resin is distinguished from the epoxy resin because the characteristic as a thermoplastic resin appears more strongly than the characteristic as a thermosetting resin because there are few epoxy groups as reaction points with respect to the molecular size.
• Epoxy resins and phenoxy resins are produced in various molecular weights depending on the purpose. Since the average molecular weight of the epoxy resin described in Patent Document 1 is about 300 to 400, it corresponds to the epoxy resin according to the above classification.
• the weight average molecular weight of the amorphous phenoxy resin as component (c) is, for example, in the range of 10,000 to 200,000, and more preferably in the range of 20,000 to 100,000.
• the weight average molecular weight of the amorphous phenoxy resin is less than 10,000, the self-film forming property is poor, and the sheet or film becomes fragile and is difficult to handle.
• a weight average molecular weight exceeds 200,000, the problem that an amorphous phenoxy resin becomes difficult to melt
• the weight average molecular weight here is a value in terms of polystyrene by GPC (gel permeation chromatography) measurement.
• amorphous phenoxy resin of component (c) include those in which X and Y in formula (1) are both a biphenylene skeleton represented by formula (2).
• X and Y in formula (1) are both a biphenylene skeleton represented by formula (2).
• at least for X, in formula (2) at least four of R 1 to R 8 are preferably alkyl groups having 4 or less carbon atoms, and the rest are hydrogen atoms, and Y is the same as X Or an unsubstituted biphenyl skeleton in which R 1 to R 8 in formula (2) are all hydrogen atoms.
• X in the formula (1) is in the 3,3 ′ position and the 5,5 ′ position, or the 2,2 ′ position and the 6,6 ′ position.
• a phenoxy resin having a weight average molecular weight in the range of 10,000 to 200,000 is more preferable.
• X in the formula (1) may be 3,3 ′, 5,5′-tetramethylbiphenylene group, and Y may be an unsubstituted biphenylene group. Particularly preferred.
• X in the formula (1) is a naphthalene skeleton represented by the formula (3), and Y is represented by the formula (2). And those having a biphenylene skeleton.
• X is preferably an asymmetrical position of the single bond of the naphthalene skeleton in Formula (3), and Y is an unsubstituted group in which R 1 to R 8 in Formula (2) are all hydrogen atoms.
• the biphenyl skeleton is preferable.
• the position of the single bond of the naphthalene skeleton is asymmetric
• the formula (3) one having a single bond at the 1-position and 6-position, or the 1-position and the 7-position of the naphthalene skeleton is preferable.
• the position of the single bond of the naphthalene skeleton is asymmetric, the molecular chain is difficult to be oriented due to structural hindrance, so that a liquid phenoxy resin soluble in a solvent can be obtained.
• the non-crystalline phenoxy resin of component (c) is preferably one in which X in formula (1) is a naphthalene skeleton having a bond at an asymmetric position, and Y is an unsubstituted biphenylene skeleton.
• X in formula (1) is a naphthalene skeleton having a bond at an asymmetric position
• Y is an unsubstituted biphenylene skeleton.
• a phenoxy resin having a weight average molecular weight in the range of 10,000 to 200,000 is more preferable.
• the content of the amorphous phenoxy resin as the component (c) is preferably in the range of 5 to 90 parts by weight, for example, with respect to 100 parts by weight of the total solids in the components (a) and (c). A range of 10 to 70 parts by weight is more preferable.
• the content of the amorphous phenoxy resin is more than 90 parts by weight with respect to the total of 100 parts by weight of the solid content, the viscosity of the varnish increases, and the workability and adhesion as an insulating layer and an adhesive layer are increased. May deteriorate, the surface condition may deteriorate, and the heat resistance may be reduced.
• it when it is set as a resin sheet, it will become hard and it will be easy to break, and handling property will fall.
• the content of the amorphous phenoxy resin is less than 5 parts by weight with respect to the total solid content of 100 parts by weight, crystals of the epoxy resin of the component (a) precipitate in the varnish state, resulting in poor curing. Cause it to happen.
• the (a) component epoxy resin containing the crystalline epoxy resin having a mesogenic group is blended with the (c) component amorphous phenoxy resin, thereby combining the varnish. While effectively preventing crystal formation in this state, excellent thermal conductivity can be imparted to the cured product.
• the compounding ratio of the component (c) to the crystalline epoxy resin having a mesogenic group of the component (a) in the epoxy resin composition of the present embodiment [crystals having a mesogenic group at (ha) / (a) The epoxy resin] is preferably in the range of 0.35 to 10, for example.
• the amorphous phenoxy resin represented by the general formula (1) is represented by, for example, an epoxy compound having two epoxy groups in one molecule represented by the following general formula (4) and the following general formula (5).
• a method of reacting a compound having two aromatic hydroxyl groups in one molecule in the presence of a polymerization catalyst, or two aromatic hydroxyl groups in one molecule represented by the following general formula (5) It can be produced by a publicly known and commonly used method of reacting a compound having an epihalohydrin with an alkali metal hydroxide.
• an epihalohydrin with an alkali metal hydroxide.
• an alkali metal hydroxide For example, epichlorohydrin is preferable.
• X and Y in the above formulas (4) and (5) have the same meanings as described above.
• an epoxy compound having two epoxy groups in one molecule represented by the general formula (4) for example, YX-4000 (tetramethylbiphenol type epoxy resin) manufactured by Mitsubishi Chemical Corporation, manufactured by Mitsubishi Chemical Corporation YL-6121H and the like.
• a solvent, a rubber component, a fluorine-based or silicone-based antifoaming agent, a leveling agent, and the like can be added to the epoxy resin composition of the present embodiment as necessary.
• an adhesion imparting agent such as a silane coupling agent or a thermoplastic oligomer can be added.
• the inorganic filler examples include alumina, silica, boron nitride, aluminum nitride, silicon nitride, calcium carbonate, magnesium carbonate and the like.
• the organic filler examples include silicon powder, nylon powder, acrylonitrile-butadiene-based crosslinked rubber, and the like. About these fillers, 1 type (s) or 2 or more types can be used.
• the epoxy resin composition of the present embodiment can be blended with a colorant such as phthalocyanine / green, phthalocyanine / blue, or carbon black, if necessary.
• examples of the alumina as the inorganic filler include crystalline alumina, fused alumina and the like, and among these, crystalline spherical alumina powder is particularly preferable.
• Crystalline alumina is excellent in the effect of increasing the thermal conductivity as compared with fused alumina.
• the use of spherical alumina also has an effect of lowering the viscosity when used as a varnish or the melt viscosity when used as a resin film as compared with crushed alumina. From the viewpoint of achieving high thermal conductivity by close packing, it is preferable that the sphericity of the spherical alumina powder is 95% or more.
• the maximum particle size of spherical alumina powder has a great influence on thermal conductivity and insulation.
• a conductive path when a voltage is applied is formed on the surface of the spherical alumina powder. Therefore, if the maximum particle diameter is set so that a plurality of spherical alumina particles can be arranged in the thickness direction of the cured product, the conductive path becomes longer and the number of insulation points between the particles increases, so that the withstand voltage increases, but heat dissipation Sex is reduced. Therefore, the maximum particle diameter of the spherical alumina powder is preferably determined in consideration of the balance between voltage resistance and heat dissipation.
• the content is preferably 50 to 95% by weight with respect to the solid content of the epoxy resin composition, and is preferably 75 to 94. More preferably, it is% by weight.
• the higher the content of the spherical alumina powder in the epoxy resin composition the higher the thermal conductivity and the lower the thermal expansion. If the content of the spherical alumina powder with respect to the solid content of the epoxy resin composition is less than 50% by weight, the effect of improving the thermal conductivity becomes insufficient, and sufficient heat dissipation may not be exhibited.
• the content of the spherical alumina powder with respect to the solid content of the epoxy resin composition is more than 95% by weight, the viscosity when used as a varnish increases or the melt viscosity when used as an adhesive film increases.
• the workability, withstand voltage characteristics, and adhesiveness of the adhesive layer may be deteriorated or the surface state may be deteriorated.
• the epoxy resin composition of the present embodiment can be prepared by mixing the above essential components and optional components. In this case, it is preferable to use a varnish containing a solvent. That is, the epoxy resin composition of the present embodiment may be dissolved or dispersed in a predetermined solvent to form a varnish.
• Solvents that can be used for the varnish include amide solvents such as N, N-dimethylformamide (DMF), N, N-dimethylacetamide, N-methyl-2-pyrrolidone (NMP), 1-methoxy-2-propano- A mixture of one or more of ether solvents such as methyl ether, methyl ethyl ketone, methyl isobutyl ketone (MIBK), ketone solvents such as cyclohexanone and cyclopentanone, aromatic solvents such as toluene and xylene, etc. it can.
• amide solvents such as N, N-dimethylformamide (DMF), N, N-dimethylacetamide, N-methyl-2-pyrrolidone (NMP), 1-methoxy-2-propano-
• ether solvents such as methyl ether, methyl ethyl ketone, methyl isobutyl ketone (MIBK), ketone solvents such as
• the varnish can be prepared, for example, according to the following procedure. First, the amorphous phenoxy resin of component (c) is dissolved in a suitable solvent while stirring in a container with a stirrer. Next, the varnish can be prepared by mixing the epoxy resin of the component (A), the curing agent of the component (B), and an optional component with this solution, stirring, and dissolving or uniformly dispersing. Depending on the type of component (a) epoxy resin, an epoxy resin may be separately prepared in a solvent and mixed. As described above, the epoxy resin composition of the present embodiment is a combination of a crystalline epoxy resin having a mesogenic group and a non-crystalline phenoxy resin, whereby a varnish of a crystalline epoxy resin having a mesogenic group is used. The precipitation of crystals can be suppressed. Therefore, it becomes possible to obtain a uniform epoxy resin composition in the state of varnish, and further, it is easy to mold the resin sheet or the like by coating and drying.
• the viscosity of the varnish is preferably in the range of 1000 to 20000 Pa ⁇ s, more preferably in the range of 2000 to 10000 Pa ⁇ s.
• the viscosity of the varnish is less than 1000 Pa ⁇ s, the spherical filler is liable to settle, and unevenness and repelling during coating are likely to occur.
• the viscosity of the varnish is larger than 20000 Pa ⁇ s, the coating property is lowered due to the decrease in fluidity, and it becomes difficult to produce a uniform coating film.
• the resin sheet of a B-stage state can be formed by apply
• the copper foil with a resin sheet can also be formed by apply
• the epoxy resin composition of the present embodiment is obtained by combining the crystalline epoxy resin having a mesogenic group and the amorphous phenoxy resin, thereby improving the flexibility of the resin sheet, and further varnishing. As a result of suppressing the precipitation of crystals therein, the generation of cracks can also be suppressed.
• the ratio of the solid resin component which occupies for an epoxy resin composition can be restrained low.
• the amount of the imidazole compound as a curing agent can be reduced as compared with, for example, a case where a phenol novolac-based curing agent component is blended. Therefore, it becomes possible to mix
• the higher the solvent residual rate the better the film supportability.
• the solvent residual ratio is preferably 5% by weight or less.
• a solvent residual rate is the value calculated
• the support material used when forming a resin sheet or a copper foil with a resin sheet examples include polyethylene terephthalate (PET), polyethylene, copper foil, aluminum foil, release paper, and the like.
• PET polyethylene terephthalate
• the thickness of the support material can be set to 10 to 100 ⁇ m, for example.
• metal foil such as copper foil and aluminum foil, as the support material
• the metal foil may be manufactured by, for example, an electrolytic method, a rolling method, or the like.
• the surface on the side in contact with the insulating layer is preferably roughened from the viewpoint of enhancing the adhesion to the insulating layer.
• the resin sheet or the copper foil with a resin sheet is laminated on a base film as a support material, and then the other surface that is not in contact with the copper foil is covered with a film as a protective material and wound into a roll.
• a protective material used at this time include polyethylene terephthalate, polyethylene, release paper, and the like.
• the thickness of the protective material can be in the range of 10 to 100 ⁇ m, for example.
• the cured product of this embodiment is prepared by, for example, preparing the B-stage resin sheet (or copper foil with a resin sheet) from the epoxy resin composition and then heating it to a temperature in the range of 150 ° C. to 250 ° C., for example. Can be produced by curing.
• the cured product thus obtained does not have crystallinity but has excellent thermal conductivity.
• the thermal conductivity of the cured product is preferably, for example, 10 W / mK or more, and more preferably 13 W / mK or more.
• the cured product has a thermal conductivity of 10 W / mK or more, it has excellent heat dissipation characteristics and can be applied to a circuit board or the like used in a high temperature environment.
• the thickness of the aluminum substrate is not particularly limited, but can generally be set to 0.5 to 3.0 mm, for example.
• an aluminum base circuit board composed of a conductor layer made of copper, an insulating adhesive layer, and an aluminum layer using the epoxy resin composition of the present embodiment
• a releasability is imparted.
• the release PET is peeled off, sandwiched between an aluminum substrate and a copper foil, and cured by heating and pressing, an adhesive layer is formed on the aluminum substrate surface, and this adhesive layer
• a method of placing a copper foil on the substrate and curing it while heating and pressing, or a method of forming an insulating adhesive layer on the aluminum substrate surface and curing it, and then forming a copper conductor layer by copper plating, etc. May be adopted.
• any of a method of volatilizing the solvent by heating after applying the varnish, a method of applying a solventless paste, or a method of bonding the resin sheet may be used.
• the weight average molecular weight of the phenoxy resin was analyzed using gel permeation chromatography. Specifically, an HLC-8320 main body manufactured by Tosoh Corporation and a column manufactured by Tosoh Corporation, TSK-gel GMHXL, TSK-gel GMHXL, and TSK-gel G2000H were used in series. Tetrahydrofuran was used as the eluent, and the flow rate was 1 ml / min. The temperature of the column chamber was 40 degrees. Detection was performed using an RI detector. The weight average molecular weight was determined using a standard polystyrene calibration curve.
• Non-volatile content of phenoxy resin solution The nonvolatile content of the phenoxy resin solution was obtained by weighing about 1 g of a sample in an aluminum cup, drying in a hot air circulation oven at 200 ° C. for 1 hour, and calculating the nonvolatile content based on the remaining weight without volatilization. .
• Synthesis Example 1-1 A separable flask equipped with a stirrer, a nitrogen blowing port, a pressure reducing device, a condenser, a reflux port equipped with an oil / water separation tank, and an alkali metal hydroxide aqueous solution dropping port, 300 parts by weight of 1,6-dihydroxynaphthalene, and 1387 of epichlorohydrin. .5 parts by weight, 208.1 parts by weight of high-solve MDM were charged, heated to 60 ° C. after nitrogen purge, dissolved, and 31.1 parts by weight of 48.8% by weight sodium hydroxide aqueous solution, paying attention to heat generation Charged and reacted for 1 hour.
• Synthesis Example 1-2 To a separable flask equipped with a reflux port equipped with a stirrer, nitrogen inlet, thermocouple, and cooler, 61.2% of the diglycidyl ether type epoxy resin of 1,6-dihydroxynaphthalene obtained in Synthesis Example 1-1 was obtained. Part by weight, 38.8 parts by weight of 4,4′-biphenol and 25 parts by weight of cyclohexanone were charged, heated to 145 ° C., dissolved, and stirred for 1 hour. Thereafter, 0.1 part by weight of tris- (2,6-dimethoxyphenyl) phosphine was charged as a reaction catalyst, and the temperature was raised to 165 ° C.
• the reaction was followed by gel permeation chromatography, and when the weight average molecular weight was reached, cyclohexanone was added and cooled to stop the reaction.
• the resulting solution was uniform and had a solid content of 30.5% by weight.
• the obtained phenoxy resin was a light brown liquid and had an epoxy equivalent of 5750 g / eq, a number average molecular weight of 7,800 and a weight average molecular weight of 47,600.
• Synthesis Example 2-1 The synthesis was performed in the same manner as in Synthesis Example 1-1 except that 2,7-dihydroxynaphthalene was used, and a diglycidyl ether type epoxy resin of 2,7-dihydroxynaphthalene was obtained.
• the obtained resin was a brown liquid, but had crystallinity and became a white solid.
• the epoxy equivalent was 145.0 g / eq.
• Synthesis Example 2-2 A synthetic example except that 56.7 parts by weight of diglycidyl ether type epoxy resin of 2,7-dihydroxynaphthalene obtained in Synthesis Example 2-1 as an epoxy resin having a naphthalene skeleton and 43.3 parts by weight of bisphenol A were charged. The reaction was terminated when the weight average molecular weight reached around 40,000 in the same procedure as in 1-2, and a solution having a solid content of 30.5% by weight was obtained. The obtained phenoxy resin was a light brown liquid, and the weight average molecular weight was 44,600.
• Synthesis Example 2-3 The synthesis was performed in the same manner as in Synthesis Example 1-1 except that 1,5-dihydroxynaphthalene was used to obtain a 1,5-dihydroxynaphthalene diglycidyl ether type epoxy resin. During the synthesis, the temperature was kept so as not to precipitate crystals. The obtained resin had crystallinity and became a white solid. Moreover, the epoxy equivalent was 149.3 g / eq.
• Synthesis Example 3-1 In a 2000 ml four-necked flask, 186.0 g (1.0 mol) of 4,4′-dihydroxybiphenyl and 600 g of diethylene glycol dimethyl ether were charged and heated to 150 ° C. with stirring under a nitrogen stream. A solution in which 52.5 g (0.3 mol) of 4-bischloromethylbenzene was dissolved was dropped, and the mixture was heated to 170 ° C. and reacted for 2 hours. After the reaction, it was dropped into a large amount of pure water and recovered by reprecipitation to obtain 202 g of a pale yellow crystalline resin.
• Synthesis Example 3-2 115 g of the resin obtained in Synthesis Example 3-1 was dissolved in 549 g of epichlorohydrin and 82.4 g of diethylene glycol dimethyl ether, and 82.4 g of 48% aqueous sodium hydroxide solution was added dropwise at 62 ° C. under reduced pressure (about 130 Torr) over 4 hours. During this time, the generated water was removed from the system by azeotropy with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After completion of the dropwise addition, the reaction was continued for another hour.
• Example 1 A diglycidyl ether type epoxy resin of 3,3 ′, 5,5′-tetramethylbiphenol (manufactured by Mitsubishi Chemical Corporation) was placed in a separable flask equipped with a reflux port equipped with a stirrer, nitrogen inlet, thermocouple, and cooler. YX-4000, epoxy equivalent 186, solid) 61.2 parts by weight, 4,4′-biphenol 33.9 parts by weight, cyclohexanone 25 parts by weight, heated to 145 ° C. and dissolved. Stir for 1 hour. Thereafter, 0.1 part by weight of tris- (2,6-dimethoxyphenyl) phosphine was charged as a reaction catalyst, and the temperature was raised to 165 ° C.
• the reaction was followed by gel permeation chromatography, and when the weight average molecular weight was reached, cyclohexanone was added and cooled to stop the reaction.
• the resulting solution was uniform and had a solid content of 29.7% by weight.
• the obtained phenoxy resin was a pale yellow liquid and had an epoxy equivalent of 11,400 g / eq, a number average molecular weight of 15,300, and a weight average molecular weight of 40,600.
• Epoxy resin composition (a) Epoxy resin Epoxy resin (1): Bisphenol type epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., trade name; YD-825GS, epoxy equivalent 180, liquid) Epoxy resin (2): Biphenylene aralkylphenol type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name: NC-3000, epoxy equivalent 275, softening point 56 ° C.) Epoxy resin (3): Triphenylmethane type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name: EPPN-501H, epoxy equivalent 170, semi-solid, softening point 60 ° C.) Epoxy resin (4): 1,5-dihydroxynaphthalene type epoxy resin obtained in Synthesis Example 2-3 (softening point 172 ° C.) Epoxy resin (5): biphenol aralkyl type epoxy resin obtained in Synthesis Example 3-2 (softening point 135 ° C.) (B
• Results are shown in Tables 1-3.
• the blending amounts of epoxy resin, curing agent, phenoxy resin, alumina powder, silane coupling agent, and solvent (cyclohexanone) are shown in parts by weight.

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