JP2019189798A - Epoxy resin composition, cured article, and sheet-like molded body - Google Patents

Abstract

To provide an epoxy resin composition excellent in heat resistance, transparency and flexibility in good balance, and applicable in various fields requiring elasticity, especially electric and electronic fields, a cured article and a sheet-like molded body by curing the epoxy resin composition.SOLUTION: There is provided an epoxy resin composition containing an epoxy resin obtained by reacting a bifunctional aliphatic epoxy compound (X) having purity of a diglycidyl body obtained by distillate purification of a reaction product of bivalent alcohol having 2 to 12 carbon atoms, and epihalohydrin of 90 mass% or more, and a total chlorine amount of 0.3 mass% or less, and a bivalent phenol compound (Y) in a presence of a catalyst, and a curing agent having an alicyclic structure. There is provided a cured article by curing the epoxy resin composition. There is provided a sheet-like molded body consisting of the cured article.SELECTED DRAWING: None

Description

  The present invention is well balanced in heat resistance, flexibility, stretchability and transparency, and is applied to various fields where heat resistance, flexibility, stretchability and transparency are required, especially in the electrical and electronic fields such as sensors and displays. The present invention relates to a possible epoxy resin composition, a cured product obtained by curing the epoxy resin composition, and a sheet-like molded body.

Epoxy resins are used in various fields because they are excellent in heat resistance, adhesion, water resistance, mechanical strength, electrical properties, and the like.
On the other hand, in recent years, demands for wearability and shape followability are increasing in the field of electronics, in particular, in various interface applications such as sensors, displays, and artificial skin for robots. That is, a flexible device that can be arranged on a curved surface or an uneven surface or can be freely deformed, and a flexible substrate that supports the device are being demanded. Moreover, in order to mount a semiconductor material, heat resistance that can withstand a solder reflow process is required.

  In order to satisfy these requirements, an epoxy resin composition using a specific highly flexible epoxy resin and a phenol novolac curing agent has been reported (for example, Patent Document 1). However, this epoxy resin composition has good flexibility, but has insufficient elongation and has a problem with transparency.

JP 2005-320477 A

  An object of the present invention is to solve the above problems, have excellent balance of heat resistance, transparency, and flexibility, and an epoxy resin composition that can be applied to various fields that require stretchability, particularly electric and electronic fields, It is providing the hardened | cured material and sheet-like molded object which harden this epoxy resin composition.

As a result of repeated studies to solve the above-mentioned problems, the present inventor uses a curing agent having an alicyclic structure as a curing agent for a specific highly flexible epoxy resin. It was found that a cured product having excellent flexibility and stretchability can be obtained.
That is, Patent Document 1 described above describes aromatic polyamines, dicyandiamides, acid anhydrides, various phenol novolac resins, and the like as curing agents used for highly flexible epoxy resins. Specifically, bisphenol A novolac resins are used. Although there is no disclosure of a curing agent having an alicyclic structure, the present inventor has sufficiently exhibited the flexibility of a highly flexible epoxy resin with the curing agent described in Patent Document 1. The cured product obtained is insufficient in stretchability, and becomes inferior in transparency by using a curing agent having an aromatic ring, and this curing agent has a cycloaliphatic structure. It was found that heat resistance, flexibility, stretchability, and transparency can be improved in a balanced manner by changing to.
The present invention has been achieved based on such findings, and the gist thereof is as follows.

[1] Bifunctional aliphatic having a diglycidyl purity of 90% by mass or more and a total chlorine content of 0.3% by mass or less obtained by distillation purification of a reaction product of a dihydric alcohol having 2 to 12 carbon atoms and an epihalohydrin An epoxy resin composition comprising an epoxy resin obtained by reacting an epoxy compound (X) and a divalent phenol compound (Y) in the presence of a catalyst, and a curing agent having an alicyclic structure.

[2] The epoxy resin composition according to [1], wherein the curing agent is an alicyclic polyamine.

[3] The epoxy resin composition according to [1] or [2], wherein the epoxy resin has a number average molecular weight of 1,000 to 20,000.

[4] A cured product obtained by curing the epoxy resin composition according to any one of [1] to [3].

[5] A sheet-like molded body comprising the cured product according to [4].

[6] The sheet-like molded product according to [5], wherein haze is 1.5% or less and YI is 6 or less.

[7] The sheet-like molded product according to [5] or [6], which has a tensile elongation of 350% or more.

[8] The sheet-like molded product according to any one of [5] to [7], wherein Tg is 30 ° C. or lower.

According to the present invention, heat resistance, flexibility, stretchability, and transparency are well balanced and various fields that require heat resistance, flexibility, stretchability, and transparency, especially sensors, displays, artificial skin for robots, etc. An epoxy resin composition applicable to the electric / electronic field such as various interfaces, and a cured product and a sheet-like molded body obtained by curing the epoxy resin composition are provided.
The epoxy resin composition of the present invention and the cured product thereof and a sheet-like molded product made of the cured product can be suitably used for optical materials as well as insulating materials, sealing materials, base materials, etc. for electric / electronic parts. it can.

  Hereinafter, embodiments of the present invention will be described in detail.

[1] Epoxy resin composition The epoxy resin composition of the present invention has a diglycidyl purity of 90% by mass or more obtained by distilling and purifying a reaction product of a dihydric alcohol having 2 to 12 carbon atoms and an epihalohydrin. An epoxy resin obtained by reacting a bifunctional aliphatic epoxy compound (X) having an amount of 0.3% by mass or less and a dihydric phenol compound (Y) in the presence of a catalyst (hereinafter referred to as “the epoxy resin of the present invention” or “ It may be referred to as “the highly flexible epoxy resin of the present invention”) and a curing agent having an alicyclic structure.

The epoxy resin composition of the present invention contains at least the epoxy resin of the present invention and a curing agent having an alicyclic structure as a curing agent. The epoxy resin composition of the present invention includes, as necessary, the present invention. Other epoxy compounds other than the epoxy resin, curing accelerator, other components, and the like can be appropriately blended.
In addition, the epoxy resin composition of this invention may contain only 1 type of the epoxy resin of this invention, and may contain 2 or more types. Similarly, the curing agent having an alicyclic structure may include only one type, or may include two or more types.

[1-1] Epoxy resin of the present invention [1-1-1] Bifunctional aliphatic epoxy compound (X)
The bifunctional aliphatic epoxy compound (X) which is a raw material for producing the epoxy resin of the present invention is obtained by distilling and purifying diglycidyl ether of a dihydric alcohol which is a reaction product of a dihydric alcohol having 2 to 12 carbon atoms and an epihalohydrin. The obtained diglycidyl body purity, that is, diglycidyl ether purity is 90% by mass or more and the total amount of chlorine is 0.3% by mass or less aliphatic epoxy resin. Examples of the dihydric alcohol include ethylene glycol, propylene Glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 2,2-dimethyl-1,3-propanediol, diethylene glycol, triethylene glycol, tetra Ethylene glycol, hexaethylene glycol, 1,4-cyclohexane dimethyl Nord, and the like. Among these, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol or 2,2-dimethyl-1,3-propanediol is effective for reducing the viscosity of the resulting epoxy resin. Is particularly preferred in that it is large and the heat resistance of the cured product is small.

  The bifunctional aliphatic epoxy compound (X) is produced by reacting a dihydric alcohol and epihalohydrin in the presence of an acidic catalyst such as sulfuric acid, boron trifluoride ethyl ether, tin tetrachloride or the like to produce a halohydrin ether body. Subsequently, the reaction product obtained by the two-step method in which the halohydrin ether is reacted with a dehydrohalogenating agent to cyclize is purified by distillation.

  The amount of the catalyst used is preferably from 0.1 to 20 mol%, particularly preferably from 0.5 to 10 mol%, based on the dihydric alcohol. If the amount of the catalyst used is too large, the amount of chlorine-containing substances produced as a by-product increases. Conversely, if the amount is too small, the reaction slows down, and in an extreme case, the reaction stops halfway.

  The epihalohydrin is preferably epichlorohydrin, and the amount used is preferably 0.8 to 1.5 equivalents, particularly 0.9 to 1.2 equivalents per hydroxyl group of the dihydric alcohol. When the amount of epichlorohydrin used is less than 0.8 equivalent, the yield of the target chlorohydrin ether body decreases, and conversely, when it exceeds 1.5 equivalents, there are many epichlorohydrin high molar adducts and chlorine-containing substances. It is not preferable because it is a by-product.

  The reaction temperature is usually 0 to 100 ° C., preferably 25 to 85 ° C. When the reaction temperature is lower than 0 ° C., the progress of the reaction is very slow. On the other hand, when the reaction temperature is higher than 100 ° C., the amount of by-produced chlorine-containing substance is not preferable.

  The reaction product of the above dihydric alcohol and epihalohydrin is reacted with the dehydrohalogenating agent without the isolation and purification of the produced halohydrin ether after the reaction is completed and after aging as necessary. Let As the dehydrohalogenating agent, sodium hydroxide is preferable. The dehydrohalogenating agent is preferably used as an aqueous solution, but in some cases, the powder or solid dehydrohalogenating agent can be added simultaneously or separately with water. The dehydrohalogenating agent is preferably added as a 10 to 50% by mass aqueous solution, more preferably as a 20 to 50% by mass aqueous solution.

  The usage-amount of dehydrohalogenating agents, such as sodium hydroxide, is 1-2 equivalent normally with respect to the hydroxyl group of a bihydric alcohol, Preferably it is 1-1.5 equivalent. When the amount of the dehydrohalogenating agent used is too small, chlorohydrin ether groups that are not glycidyl etherified remain, resulting in an increase in the amount of chlorine. Moreover, when there is too much usage-amount of a dehydrohalogenating agent, since the hydration reaction of the produced | generated glycidyl ether is accelerated | stimulated and glyceryl etherified substance increases, it is unpreferable.

  The reaction temperature with the dehydrohalogenating agent is usually in the range of 20 to 100 ° C, preferably in the range of 30 to 80 ° C. Although the reaction time with a dehydrohalogenating agent changes with the usage-amount of a dehydrohalogenating agent and the presence or absence of solvent use, it is 0.1 to 10 hours normally.

  Isolation of the diglycidyl ether after completion of the dehydrohalogenation reaction can be performed by a conventional method. For example, a diglycidyl ether can be obtained by adding a non-water-soluble solvent such as a hydrocarbon as necessary, washing with water to remove the generated salt, and then removing the solvent, dehydrating, and filtering.

  Further, the diglycidyl ether is purified by distillation in order to achieve a purity of 90% by mass or more and a total chlorine content of 0.3% by mass or less. In order to prevent decomposition of diglycidyl ether, distillation purification is usually performed under reduced pressure, the number of distillation stages is preferably 5 or more, and it is preferable to use equipment with high vacuum and low pressure loss.

  The temperature of the crude liquid during distillation is usually 270 ° C. or lower, preferably 240 ° C. or lower. When the temperature of the crude liquid exceeds 270 ° C., the decomposition of the high boiling point chlorine-containing substance becomes remarkable, and the decomposed chlorine-containing substance is mixed into the product fraction, so that the total chlorine amount of the product becomes high. Moreover, the dimerization reaction between diglycidyl ethers also occurs, which is not preferable because the product recovery rate decreases.

  The diglycidyl purity of the bifunctional aliphatic epoxy compound (X) used for the production of the epoxy resin of the present invention is 90% by mass or more, preferably 92% by mass or more, and more preferably 95% by mass or more. The total chlorine content is 0.3% by mass or less, preferably 0.25% by mass or less, more preferably 0.2% by mass or less.

  Examples of impurities other than the diglycidyl compound contained in the bifunctional aliphatic epoxy compound (X) include those in which alcoholic hydroxyl groups remain unreacted and those that remain as chlorohydrin groups without being dehydrochlorinated. In these, since the terminal group is not an epoxy group, the copolymerization reaction with the dihydric phenol compound (Y) stops here and does not reach a predetermined molecular weight, or the number of functional groups of the resulting highly flexible epoxy resin is Since it becomes smaller than 2 and the performance of hardened | cured material falls, it is unpreferable when diglycidyl body purity is lower than 90 mass%. Further, when the total chlorine content of the bifunctional aliphatic epoxy compound (X) is more than 0.3% by mass, it is not preferable because a minute circuit pattern is corroded by chlorine impurities particularly when used as an electronic insulating material.

  In addition, the diglycidyl body purity and total chlorine amount of bifunctional aliphatic epoxy compound (X) are measured by the method as described in the term of the below-mentioned Example.

  In the production of the epoxy resin of the present invention, such bifunctional aliphatic epoxy compound (X) may be used alone or in combination of two or more.

[1-1-2] Dihydric phenol compound (Y)
The divalent phenol compound (Y) that is a raw material for producing the epoxy resin of the present invention may be any one as long as two hydroxyl groups are bonded to an aromatic ring. Examples thereof include bisphenols such as bisphenol A, bisphenol F, bisphenol S, bisphenol B, bisphenol AD, and bisphenol acetophenone, biphenol, catechol, resorcin, hydroquinone, dihydroxynaphthalene, and the like. Further, those in which the hydrogen atom of these dihydric phenol compounds is substituted with a non-interfering substituent such as an alkyl group, an aryl group, an ether group, or an ester group can be mentioned. Among these dihydric phenols, preferred are bisphenol A, bisphenol F, bisphenol S, bisphenol acetophenone, 4,4′-biphenol, 3,3 ′, 5,5′-tetramethyl-4,4′-biphenol. , Resorcin, hydroquinone, dihydroxynaphthalene.

  In producing the epoxy resin of the present invention, these dihydric phenol compounds (Y) may be used alone or in combination of two or more.

[1-1-3] Compounding Equivalent Ratio of Bifunctional Aliphatic Epoxy Compound (X) and Divalent Phenol Compound (Y) Bifunctional Aliphatic Epoxy Compound (X) and Divalent Phenol Used for Production of Epoxy Resin of the Present Invention The blending equivalent ratio of (Y) is preferably an epoxy group derived from the bifunctional aliphatic epoxy compound (X): a phenolic hydroxyl group derived from the divalent phenol compound (Y) = 1: 0.1-3, The ratio is preferably 1: 0.3 to 1.5, particularly preferably 1: 0.5 to 0.995. When the equivalent of the phenolic hydroxyl group to the epoxy group is less than 1 and the phenolic hydroxyl group is small, the end of the highly flexible epoxy resin obtained theoretically is an epoxy group, and conversely, the phenolic hydroxyl group equivalent is from 1. When large, the terminal of the highly flexible epoxy resin obtained becomes a phenolic hydroxyl group. In order to obtain a high-flexibility epoxy resin having a high molecular weight with a number average molecular weight of 10,000 or more, it is preferable that epoxy group: phenolic hydroxyl group = 1: 0.90 to 1.10, and further 1: 0. 92 to 1.05 is preferable, particularly 1: 0.93 to 1.00 is preferable, and 1: 0.95 to 0.995 is most preferable. Even if the equivalent ratio is less than 0.90 or greater than 1.10, the molecular weight cannot be sufficiently increased.

[1-1-4] Other raw materials As a raw material of the epoxy resin of the present invention, other bifunctional epoxy resins can be used in combination with the bifunctional aliphatic epoxy compound (X). Examples of bifunctional epoxy resins that can be used in combination include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, biphenyl type epoxy resins, and other bifunctional glycidyl ether type epoxy resins and bifunctional glycidyl ester type epoxies. Hydrogenated epoxy resin such as resin, bifunctional glycidylamine type epoxy resin, bifunctional linear aliphatic epoxy resin, bifunctional alicyclic epoxy resin, bifunctional heterocyclic epoxy resin, hydrogenated bisphenol A type epoxy resin Is mentioned. Moreover, it is also possible to use a trifunctional or higher functional epoxy compound in combination so that the resulting highly flexible epoxy resin does not gel. Further, it is possible to use a small amount of a monofunctional epoxy compound, but in this case, since the terminal group of the resulting highly flexible epoxy resin becomes a non-reactive group, it is not preferable to use a large amount in combination.

  In addition to the dihydric phenol compound (Y), other compounds having a group that reacts with an epoxy group can be used in combination as a raw material for the epoxy resin of the present invention. Examples of other compounds that can be used in combination include compounds that are bifunctional in total among any of thiol groups, carboxylic acid groups, amino groups, isocyanate groups, cyanate groups, and phenolic hydroxyl groups. It is also possible to use a trivalent or higher valent phenol compound or a compound that becomes trifunctional or higher with the above reactive group to such an extent that the resulting highly flexible epoxy resin does not gel. Furthermore, it is possible to use a small amount of a monofunctional phenol compound or a monofunctional compound having the above-mentioned reactive group. In this case, the terminal group of the resulting highly flexible epoxy resin becomes a non-reactive group. Therefore, it is not preferable to use a large amount together.

[1-1-5] Catalyst The catalyst used for the production of the epoxy resin of the present invention may be any compound as long as it has a catalytic ability to promote the reaction between an epoxy group and a phenolic hydroxyl group. For example, alkali metal compounds, organic phosphorus compounds, tertiary amines, quaternary ammonium salts, cyclic amines, imidazoles and the like can be mentioned.

  Specific examples of the alkali metal compound include alkali metal hydroxides such as sodium hydroxide, lithium hydroxide and potassium hydroxide, alkali metal salts such as sodium carbonate, sodium bicarbonate, sodium chloride, lithium chloride and potassium chloride, sodium Examples include alkali metal alkoxides such as methoxide and sodium ethoxide, alkali metal phenoxides, alkali metal hydrides such as sodium hydride and lithium hydride, and alkali metal salts of organic acids such as sodium acetate and sodium stearate.

  Specific examples of organic phosphorus compounds include tri-n-propylphosphine, tri-n-butylphosphine, triphenylphosphine, tetramethylphosphonium bromide, tetramethylphosphonium iodide, tetramethylphosphonium hydroxide, trimethylcyclohexylphosphonium chloride, trimethyl. Cyclohexylphosphonium bromide, trimethylbenzylphosphonium chloride, trimethylbenzylphosphonium bromide, tetraphenylphosphonium bromide, triphenylmethylphosphonium bromide, triphenylmethylphosphonium iodide, triphenylethylphosphonium chloride, triphenylethylphosphonium bromide, triphenylethylphosphonium iodide The Phenyl benzyl phosphonium chloride, triphenyl benzyl phosphonium bromide and the like.

  Specific examples of the tertiary amine include triethylamine, tri-n-propylamine, tri-n-butylamine, triethanolamine, benzyldimethylamine and the like.

  Specific examples of the quaternary ammonium salt include tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium hydroxide, triethylmethylammonium chloride, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, tetrapropylammonium bromide, Tetrapropylammonium hydroxide, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, benzyltrimethylammonium hydroxide, benzyltributylammonium chloride Id, and a phenyl trimethyl ammonium chloride.

Specific examples of imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole and the like.
Specific examples of cyclic amines include 1,8-diazabicyclo (5,4,0) undecene-7,1,5-diazabicyclo (4,3,0) nonene-5.
These catalysts may use only 1 type and may mix and use 2 or more types.

  Usually, the amount of catalyst used is 0.001 to 1% by mass in the solid content of the reaction. However, when an alkali metal compound is used, the alkali metal component remains in the epoxy resin obtained, and the printed wiring board using the same remains. In order to extremely deteriorate the insulating properties, when an alkali metal compound is used, it is used so that the total content of Li, Na and K in the obtained epoxy resin is usually 100 ppm or less, preferably 50 ppm or less. Also, when an organophosphorus compound is used as a catalyst, it remains as a catalyst residue in the epoxy resin and deteriorates the insulating properties of the printed wiring board in the same manner as the alkali metal residue, so when using an organophosphorus compound, It is used so that the content of phosphorus in the obtained epoxy resin is usually 300 ppm or less, preferably 150 ppm or less.

[1-1-6] Solvent A solvent may be used in the synthesis reaction step during the production of the epoxy resin of the present invention, and any solvent can be used as long as it dissolves the resulting epoxy resin. Good. Examples include aromatic solvents, ketone solvents, amide solvents, glycol ether solvents, and the like.

Specific examples of the aromatic solvent include benzene, toluene, xylene and the like.
Specific examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone, 4-heptanone, 2-octanone, cyclohexanone, acetylacetone, and dioxane.
Specific examples of the amide solvent include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, 2-pyrrolidone, N-methylpyrrolidone and the like.

  Specific examples of the glycol ether solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol. Examples thereof include mono-n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol mono-n-butyl ether, propylene glycol monomethyl ether acetate.

  These solvents may be used alone or in combination of two or more.

  The solid content concentration in the synthesis reaction during the production of the epoxy resin of the present invention is preferably 35 to 100% by mass. When a highly viscous product is produced during the reaction, the reaction can be continued by adding a solvent. After completion of the reaction, the solvent can be removed as necessary, or further added.

[1-1-7] Reaction conditions The synthesis reaction during the production of the epoxy resin of the present invention is carried out at a reaction temperature at which the used catalyst does not decompose. The reaction temperature is preferably 50 to 230 ° C, more preferably 120 to 200 ° C. When using a low boiling point solvent such as acetone or methyl ethyl ketone, the reaction temperature can be ensured by carrying out the reaction under high pressure using an autoclave.

[1-1-8] Physical Properties The number average molecular weight of the epoxy resin of the present invention is preferably 1,000 to 20,000, more preferably 1,000 to 15,000, and still more preferably 1,500 to 5,000. 12,000, particularly preferably 2,000 to 10,000. If the number average molecular weight is not less than the above lower limit, the outgas amount in the reliability test is small and the flexibility tends to be excellent, and if it is not more than the above upper limit, the handleability is likely to be excellent.

  In addition, the number average molecular weight (Mn) of an epoxy resin can be measured as a polystyrene conversion value by gel permeation chromatography.

  The epoxy equivalent of the epoxy resin of the present invention is preferably 300 to 12,000 g / eq, more preferably 400 to 11,000 g / eq, and particularly preferably 900 to 10,000 g / eq. If the epoxy equivalent is greater than or equal to the above lower limit, the amount of outgas in the reliability test is small and the flexibility tends to be excellent, and if it is less than or equal to the above upper limit, it crosslinks with other components to improve heat resistance.

  The “epoxy equivalent” is defined as “a mass of an epoxy resin containing one equivalent of an epoxy group” and can be measured according to JIS K7236.

[1-2] Curing Agent The epoxy resin composition of the present invention is characterized by using a curing agent having an alicyclic structure as a curing agent for the epoxy resin of the present invention.

The curing agent having an alicyclic structure may be any substance that has an alicyclic structure and contributes to the crosslinking reaction and / or chain extension reaction between epoxy groups of the epoxy resin, and is not particularly limited. Examples thereof include alicyclic polyamines and alicyclic acid anhydrides. More specifically, 1,4-diazabicyclo-2,2,2-octane, 1,8-diazabicyclo-5,4,0-undec-7-ene, N, N′-dimethylpiperazine, N-aminoethylpiperazine , Mensendiamine, isophoronediamine, hexamethylenetetramine, methylenebiscyclohexanamine, 1,3-bisaminomethylcyclohexane, norbornenediamine, 1,2-diaminocyclohexane, and alicyclic polyamines modified with epoxy or ethylene oxide , Dimer acid modified, Mannich modified, Michael addition, thiourea condensation, ketiminated modified alicyclic polyamine, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, and the like.
Among these, alicyclic polyamines are preferable, and among them, isophoronediamine, hexamethylenetetramine, methylenebiscyclohexanamine, 1,3-bisaminomethylcyclohexane, norbornenediamine, 1,2-diaminocyclohexane, and modified products thereof are particularly preferable. preferable.

  Commercially available products may be used as the curing agent having an alicyclic structure, such as “jER Cure 113”, “jER Cure ST-14” manufactured by Mitsubishi Chemical Corporation, “Licacid MH-700” manufactured by Shin Nippon Rika Co., Ltd. be able to.

  The epoxy resin composition of the present invention may contain a curing agent other than the above-described curing agent having an alicyclic structure, and in that case, as a curing agent other than the curing agent having an alicyclic structure, , Polyfunctional phenols, polyisocyanate compounds, amine compounds, acid anhydride compounds, imidazole compounds, amide compounds, cationic polymerization initiators, organic phosphines, etc., but curing with an alicyclic structure In order to obtain the effect of the present invention more reliably by using an agent, when using other curing agents other than the curing agent having an alicyclic structure, the total of the curing agent having an alicyclic structure and the other curing agent The ratio of the other curing agent with respect to is preferably 70% by mass or less, more preferably 50% by mass or less, and particularly preferably 0 to 30% by mass.

  Content of curing agent in epoxy resin composition of the present invention (when using other curing agent other than curing agent having alicyclic structure, total amount of curing agent having alicyclic structure and other curing agent Content) is 100 parts by mass of the epoxy resin of the present invention (when other epoxy compounds described later other than the epoxy resin of the present invention are included), the total content of the epoxy resin of the present invention and other epoxy resins) The amount is preferably 0.1 to 100 parts by weight. Further, it is more preferably 80 parts by weight or less, still more preferably 60 parts by weight or less, and particularly preferably 40 parts by weight or less.

  In the present invention, “solid content” means a component excluding a solvent, and includes not only a solid epoxy resin or an epoxy compound but also a semi-solid or viscous liquid. The “total epoxy component” means the total of the epoxy resin of the present invention and other epoxy compounds described later.

[1-3] Other epoxy compounds When the epoxy resin composition of the present invention contains other epoxy compounds other than the epoxy resin of the present invention, examples of the other epoxy compounds include bisphenol A type epoxy resins and bisphenols. F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, glycidyl ether type epoxy resin such as cresol novolac type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, linear fat 1 type (s) or 2 or more types of various epoxy resins, such as a group epoxy resin, an alicyclic epoxy resin, and a heterocyclic epoxy resin, are mentioned.

  When the epoxy resin composition of the present invention contains the epoxy resin of the present invention and another epoxy compound, the proportion of the other epoxy compounds in the total epoxy component as a solid content in the epoxy resin composition is preferably It is 5% by mass or more, more preferably 10% by mass or more, on the other hand, preferably 95% by mass or less, more preferably 90% by mass or less. When the ratio of the other epoxy compound is not less than the above lower limit value, the effect of improving physical properties by blending the other epoxy compound can be sufficiently obtained. On the other hand, when the ratio of the other epoxy compound is not more than the above upper limit value, the effect of improving the flexibility and flexibility by the epoxy resin of the present invention can be sufficiently obtained.

[1-4] Solvent The epoxy resin composition of the present invention may be diluted by blending a solvent in order to appropriately adjust the viscosity of the epoxy resin composition during handling such as when a coating film is formed. In the epoxy resin composition of the present invention, the solvent is used in order to ensure the handleability and workability in the molding of the epoxy resin composition, and the amount used is not particularly limited. In the present invention, the term “solvent” and the term “solvent” are distinguished from each other depending on the form of use, but the same or different ones may be used independently.

  Examples of the solvent that can be contained in the epoxy resin composition of the present invention include acetone, methyl ethyl ketone, toluene, xylene, methyl isobutyl ketone, ethyl acetate, ethylene glycol monomethyl ether, N, N-dimethylformamide, N, N-dimethylacetamide, Methanol, ethanol and the like can be mentioned, and these solvents can be used as a mixed solvent of two or more as appropriate.

[1-5] Other components The epoxy resin composition of the present invention may contain other components in addition to the components listed above. Other components can be used in appropriate combination depending on the desired physical properties of the epoxy resin composition.

  For example, for the purpose of improving various properties such as the effect of lowering the curing shrinkage of the resulting cured product and the effect of reducing the coefficient of thermal expansion, an inorganic filler is blended in the epoxy resin composition of the present invention. Applications can be developed in the electronic field, particularly in liquid semiconductor encapsulants. In order to impart toughness, organic fillers such as rubber particles and acrylic particles may also be included.

Inorganic fillers that can be used include powdered reinforcing agents and fillers, such as metal oxides such as aluminum oxide and magnesium oxide, metal carbonates such as calcium carbonate and magnesium carbonate, diatomaceous earth powder, and basic magnesium silicate. Fired clay, finely divided silica, fused silica, crystalline silica and other metal compounds, aluminum hydroxide and other metal hydroxides, kaolin, mica, quartz powder, graphite, molybdenum disulfide and the like.
These inorganic fillers are usually 10 to 900 parts by mass with respect to 100 parts by mass of the sum of the epoxy resin (the epoxy resin of the present invention and other epoxy compounds used as necessary, the same applies hereinafter) and the curing agent. Can be blended.

  Furthermore, it is also possible to mix | blend a fibrous reinforcement and a filler. For example, glass fiber, ceramic fiber, carbon fiber, alumina fiber, silicon carbide fiber, boron fiber and the like can be mentioned. Also, organic fiber, inorganic fiber cloth or non-woven fabric can be used. Furthermore, these inorganic fillers, fibers, cloths, and nonwoven fabrics are also used after surface treatment such as silane coupling agent, titanate coupling agent, aluminate coupling agent or primer treatment on the surface thereof. it can.

  Furthermore, the following components (1) and (2) can be added to the epoxy resin composition of the present invention as required.

(1) Coupling agents, plasticizers, diluents, flexibility imparting agents, dispersants, wetting agents, colorants, pigments, UV absorbers, hindered amine light stabilizers and other light stabilizers, antioxidants, de-binding agents Foaming agent, flow control agent, etc.
These are usually blended in an amount of 0.1 to 20 parts by mass per 100 parts by mass of the sum of the epoxy resin and the curing agent.

(2) Various curable monomers, oligomers and synthetic resins for the purpose of improving the properties of the resin in the final coating. For example, one or more of cyanate ester resin, acrylic resin, silicone resin, polyester resin and the like.
The blending ratio of these resins is preferably 50 parts by mass or less with respect to an amount within a range not impairing the original properties of the epoxy resin composition of the present invention, that is, 100 parts by mass of the sum of the epoxy resin and the curing agent.
In order to impart flame retardancy, non-halogen type P-based, N-based, Si-based flame retardants, and the like may be added.

[2] Cured product A cured product can be obtained by curing the epoxy resin composition of the present invention. Here, “curing” means that the epoxy resin is intentionally cured by heat and / or light or the like, and the degree of curing may be controlled by desired physical properties and applications.

  The curing method of the epoxy resin composition when curing the epoxy resin composition of the present invention to obtain a cured product varies depending on the blending component and blending amount in the epoxy resin composition, and the shape of the blend, but usually 23 A heating condition of ˜200 ° C. for 5 minutes to 24 hours can be mentioned. This heating is a two-stage treatment of a primary heating at 23 to 160 ° C. for 5 minutes to 24 hours and a secondary heating at 80 to 200 ° C. that is 40 to 177 ° C. higher than the primary heating temperature for 5 minutes to 24 hours. It is preferable to carry out by a three-stage treatment in which tertiary heating is performed at 100 to 200 ° C., which is higher than the secondary heating temperature, for 5 minutes to 24 hours, from the viewpoint of reducing poor curing.

  When producing a cured product as a semi-cured product, the curing reaction of the epoxy resin composition may be advanced to such an extent that the shape can be maintained by heating or the like. When the epoxy resin composition contains a solvent, most of the solvent is removed by techniques such as heating, reduced pressure, and air drying, but 5% by weight or less of the solvent may be left in the semi-cured product.

[3] Sheet-shaped molded product The sheet-shaped molded product of the present invention is a sheet-shaped molded product made of the cured product of the present invention obtained by curing the epoxy resin composition of the present invention.

  The sheet-like molded product of the present invention can be produced by curing the epoxy resin composition of the present invention in a state adjusted to a sheet shape having a predetermined thickness. Alternatively, it can be produced by molding a semi-cured product obtained from the epoxy resin composition of the present invention into a sheet having a predetermined thickness and further curing it.

  In addition, there is no restriction | limiting in particular in the thickness of the sheet-like molded object of this invention, Preferably it is 0.05 mm or more, More preferably, it is 0.1 mm or more, Most preferably, it is 0.2 mm or more.

  The sheet-like molded product of the present invention preferably has a haze of 1.5% or less and a YI of 6 or less as measured in the Examples section below. If the haze and YI are less than or equal to the above upper limits, it is easy to satisfy the required characteristics of transparency. From the viewpoint of transparency, the haze of the sheet-like molded product of the present invention is more preferably 1.3% or less, and further preferably 1.0% or less. YI is more preferably 4 or less, and still more preferably 1 or less.

  The sheet-like molded product of the present invention preferably has a glass transition temperature (Tg) of 30 ° C. or less as measured in the Examples section described below. If Tg is below the above upper limit, the change in storage elastic modulus at room temperature or higher is small, which is preferable. From this viewpoint, the Tg of the sheet-like molded product of the present invention is more preferably 25 ° C. or less, further preferably 10 ° C. or less, and particularly preferably 0 ° C. or less.

  The sheet-like molded product of the present invention preferably has a 5% thermal decomposition temperature (Td5) of 260 ° C. or higher as measured in the Examples section below. If Td5 is at least the above lower limit, it is preferable because it can withstand a reflow soldering (solder reflow) step. From this viewpoint, Td5 of the sheet-like molded body of the present invention is more preferably 300 ° C. or higher, and further preferably 350 ° C. or higher.

  The sheet-like molded product of the present invention preferably has a tensile elongation measured in the section of Examples below of 350% or more. If the tensile elongation is not less than the above lower limit, the required properties of flexibility and stretchability are easily satisfied. From the viewpoints of flexibility and stretchability, the tensile elongation of the sheet-like molded body of the present invention is more preferably 355% or more, for example, 355 to 400%.

  The sheet-like molded product of the present invention preferably has an elastic modulus of 8 MPa or less as measured in the Examples section described below. If the elastic modulus is less than or equal to the above upper limit, the required characteristics of flexibility are easily satisfied. From the viewpoint of flexibility, the elastic modulus of the sheet-shaped molded body of the present invention is more preferably 5 MPa or less, for example, 5 to 0.1 MPa.

[4] Use The epoxy resin composition of the present invention provides a cured product excellent in heat resistance, flexibility, stretchability, and transparency, and is a laminate, sealing material, adhesive, paint, and electrical insulating material. Can be used for etc. In particular, flexible devices for various interfaces such as sensors, displays, and artificial skin for robots, flexible substrates that support them, sealing materials for semiconductor encapsulation, powder coatings for electrical insulation, resist inks, electrical / electronics It can be used for casting materials for parts, adhesives for electrical and electronic parts, insulating films, and the like.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited at all by the following example. In addition, the value of various manufacturing conditions and evaluation results in the following examples has a meaning as a preferable value of the upper limit or the lower limit in the embodiment of the present invention, and the preferable range is the above-described upper limit or lower limit value. A range defined by a combination of values of the following examples or values of the examples may be used. Hereinafter, all “parts” indicate “parts by mass”.

[Various analysis / evaluation / measurement methods]
The methods for analyzing, evaluating, and measuring various physical properties and characteristics are as follows.

  The evaluation method of the obtained cured epoxy resin is as follows.

1) Elastic modulus About the epoxy resin hardened | cured material (test piece thickness 4mm), it cut out to length 50mm and width 10mm, and produced the test piece. The test piece was measured using a dynamic viscoelasticity measuring device (EXSTAR DMS6100, manufactured by SII Nano Technology Co., Ltd.) at a frequency of 1 Hz, a heating rate of 2 ° C./min, and a measurement condition of a double-end bending mode. The storage elastic modulus E ′ in was taken as the elastic modulus.

2) Glass transition temperature (Tg)
About the epoxy resin hardened | cured material (test piece thickness 4mm), it cut out to length 50mm and width 10mm, and produced the test piece. The test piece was measured using a dynamic viscoelasticity measuring apparatus (EXSTAR DMS6100, manufactured by SII Nano Technology Co., Ltd.) at a frequency of 1 Hz, a heating rate of 2 ° C./min, and measurement conditions of a double-end bending mode. The temperature at which the tan δ curve showed the maximum value was defined as the glass transition temperature (Tg).

3) 5% weight loss temperature (Td5)
About the cured epoxy resin (test piece thickness 4mm), differential thermothermal weight simultaneous measurement device (SII Nano Technology,
EXSTAR TG / DTA7200) was used, and the temperature was increased at a rate of 5 ° C./minute, the measurement temperature range: 30 ° C. to 600 ° C., and the nitrogen: flow rate 200 mL / min. The temperature at the time was 5% weight loss temperature (Td5).

4) Tensile elongation The epoxy resin cured product (test piece thickness 0.12 mm) was subjected to a tensile test at a test speed of 200 mm / min according to JIS K7161, and the tensile elongation at that time was measured.

5) Haze About the epoxy resin hardened | cured material (test piece thickness 0.12mm), haze was measured using the haze meter (Nippon Denshoku Industries Co., Ltd. make, NDH-5000) according to JISK7105.

6) YI
About cured epoxy resin (test piece thickness 0.12 mm), YI was measured using a color meter (manufactured by Suga Test Instruments Co., Ltd., SC-T) according to JIS K7373.

The analysis method of the bifunctional aliphatic epoxy compound (X) is as follows.
Diglycidyl purity: Analysis was carried out by gas chromatography using an FDI detector, and the area% of the total peak area of the diglycidyl peak was measured as mass%.
Total chlorine content: quantified by fluorescent X-ray method.

Moreover, the epoxy equivalent of bifunctional aliphatic epoxy compound (X), the number average molecular weight of the obtained epoxy resin, and the measuring method of an epoxy equivalent are as follows.
Number average molecular weight: It was measured as a polystyrene equivalent value by gel permeation chromatography.
Epoxy equivalent: Measured by potentiometric titration according to JIS K7236 and converted to a value as resin solids.

[Manufacture of epoxy resin]
As an epoxy resin, what was manufactured as follows was used.

<Manufacture of epoxy resin (A-1)>
First, 141.8 parts of 1,6-hexanediol and 0.51 part of boron trifluoride ethyl ether previously heated to 45 ° C. were charged into a 1 L glass flask equipped with a stirrer, a dropping funnel and a thermometer, and 80 ° C. Until heated. Epichlorohydrin (244.3 parts) was added dropwise over a period of time so as not to exceed 85 ° C. The mixture was aged for 1 hour while maintaining at 80 to 85 ° C, and then cooled to 45 ° C. To this was added 528.0 parts of a 22% by weight aqueous sodium hydroxide solution, heated to 45 ° C. and vigorously stirred for 4 hours. The mixture was cooled to room temperature, the aqueous phase was separated and removed, and heated under reduced pressure to remove unreacted epichlorohydrin and water to obtain 283.6 parts of crude 1,6-hexanediol diglycidyl ether.
This crude 1,6-hexanediol diglycidyl ether was purified by distillation in an Oldshaw distillation column (15 stages), and a fraction at a pressure of 1300 Pa and 170-190 ° C. was used as the main fraction, 127.6 parts of glycidyl ether were obtained.
The 1,6-hexanediol diglycidyl ether had the following diglycidyl purity, total chlorine content, and epoxy equivalent.
Diglycidyl purity: 97% by mass
Total chlorine content: 0.15% by mass
Epoxy equivalent: 116 g / eq

100 parts of the obtained bifunctional epoxy compound (1,6-hexanediol diglycidyl ether) and 69.3 parts of bisphenol F (phenolic hydroxyl group equivalent: 100 g / eq), ethyltriphenylphosphonium iodide (30 mass% methyl) 0.13 parts of a cellosolve solution) was put in a pressure resistant reactor, and a polymerization reaction was performed at 165 to 170 ° C. for 5 hours in a nitrogen gas atmosphere to obtain an epoxy resin (A-1).
The epoxy equivalent of the obtained epoxy resin (A-1) was 1,000 g / eq, and the number average molecular weight was 3,000.

<Manufacture of epoxy resin (A-2)>
Bisphenol F (phenolic hydroxyl group equivalent: 100 g / eq) 53.5 is added to 100 parts of a bifunctional epoxy compound (1,6-hexanediol diglycidyl ether) produced in the same manner as in the production of the epoxy resin (A-1). The epoxy resin (A-2) was prepared in the same manner as in the production of the epoxy resin (A-1) except that 0.08 part of ethyltriphenylphosphonium iodide (30 mass% methyl cellosolve solution) was used. Obtained.
The epoxy equivalent of the obtained epoxy resin (A-2) was 500 g / eq, and the number average molecular weight was 1,600.

[Curing agent]
As the curing agent, the following curing agents (B-1) and (B-2) were used.
Curing agent (B-1): Alicyclic polyamine (JER Cure ST-14, manufactured by Mitsubishi Chemical Corporation)
Curing agent (B-2): aromatic polyamine (Mitsubishi Chemical Co., Ltd. jER Cure W)

[Examples 1-2, Comparative Examples 1-2]
The epoxy resin composition is prepared by blending the epoxy resin (A-1) or (A-2) with the curing agent (B-1) or (B-2) in the ratio shown in Table 1. The composition was sandwiched between Si-coated mold release PET, adjusted to a desired thickness and cured to obtain cured epoxy resins.
When the curing agent (B-1) is used, the curing conditions are 40 ° C. for 16 hours, and then 80 ° C. for 6 hours. When the curing agent (B-2) is used, the curing condition is 40 ° C. for 16 hours, and then 100 ° C. For 3 hours, and further at 160 ° C. for 4.5 hours.
The evaluation results of the properties (elastic modulus, Tg, Td5, tensile elongation, haze, YI) of the obtained cured epoxy resin are shown in Table 1.

[Evaluation results]
From the results of Table 1, the cured epoxy resins of Examples 1 and 2 obtained from the epoxy resin composition of the present invention using an alicyclic polyamine as a curing agent were compared using an aromatic polyamine as a curing agent. Compared to the cured epoxy resins of Examples 1 and 2, it can be seen that the balance of transparency (haze, YI) and flexibility (low elasticity, high elongation) is excellent.
Moreover, it turns out that Td5 is higher than solder reflow temperature (260 degreeC), and the epoxy resin hardened | cured material of Example 1, 2 is excellent in heat resistance. Further, the cured epoxy resins of Examples 1 and 2 are practically preferable because of low Tg and small change in storage elastic modulus at 30 ° C. or higher.

Claims (8)

A difunctional aliphatic epoxy compound having a diglycidyl purity of 90% by mass or more and a total chlorine content of 0.3% by mass or less obtained by distillation purification of a reaction product of a dihydric alcohol having 2 to 12 carbon atoms and epihalohydrin ( An epoxy resin obtained by reacting X) with a dihydric phenol compound (Y) in the presence of a catalyst;
An epoxy resin composition containing a curing agent having an alicyclic structure.   The epoxy resin composition according to claim 1, wherein the curing agent is an alicyclic polyamine.   The epoxy resin composition according to claim 1 or 2, wherein the epoxy resin has a number average molecular weight of 1,000 to 20,000.   Hardened | cured material formed by hardening | curing the epoxy resin composition in any one of Claim 1 thru | or 3.   The sheet-like molded object which consists of hardened | cured material of Claim 4.   The sheet-like molded product according to claim 5, wherein the haze is 1.5% or less and the YI is 6 or less.   The sheet-like molded product according to claim 5 or 6, wherein the tensile elongation is 350% or more.   Tg is 30 degrees C or less, The sheet-like molded object in any one of Claim 5 thru | or 7.