Transparent resin composition

Abstract

To provide a transparent resin composition which enables formation of a cured product which is excellent in warpage suppression and yellowing resistance.SOLUTION: A transparent resin composition contains (A) an epoxy resin having a fluoroalkyl group and / or an alicyclic structure, (B) a phosphite-based antioxidant, and (C) a curing accelerator.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a transparent resin composition.

Background Art

[0002] Transparent resin compositions are used as encapsulating materials and adhesive materials for transparent parts of electronic devices such as LED devices and transparent FPCs. As such a transparent resin composition, for example, Patent Document 1 discloses a resin composition containing a bisphenol AF type epoxy resin, a thermoplastic resin, and a curing accelerator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The thermosetting resin composition as described in Patent Document 1 may warp due to shrinkage during curing. Therefore, there is a demand for a resin composition capable of forming a cured product excellent in warp suppression. Further, in order to be used for transparent parts of electronic devices such as LED devices and transparent FPCs, there is a demand for a transparent resin composition capable of forming a cured product excellent in yellowing resistance.

[0005] The present invention has been made paying attention to the above circumstances, and an object thereof is to provide a transparent resin composition capable of forming a cured product excellent in warp suppression and yellowing resistance.

Means for Solving the Problems

[0006] The present invention capable of achieving the above object is as follows. [1] The following components (A) to (C): (A) An epoxy resin having a fluoroalkyl group and / or an alicyclic structure, (B) A phosphite antioxidant, and (C) A curing accelerator A transparent resin composition containing the same. [2] The transparent resin composition according to [1] above, wherein component (B) has a bisphenol structure or a hydrogenated bisphenol structure. [3] The transparent resin composition according to [1] or [2] above, wherein the content of component (B) is 0.1 to 10% by mass based on the non-volatile content of the transparent resin composition. [4] The transparent resin composition according to any one of [1] to [3] above, further containing a liquid epoxy resin having neither a fluoroalkyl group nor an alicyclic structure as component (D). [5] The transparent resin composition according to any one of [1] to [4] above, further containing a phenoxy resin as component (E). [6] The transparent resin composition according to any one of [1] to [5] above, further containing a silane coupling agent selected from the group consisting of a (meth)acryloyl group-containing silane coupling agent, an epoxy group-containing silane coupling agent, and a vinyl group-containing silane coupling agent as component (F). [7] The transparent resin composition according to any one of [1] to [6] above, further containing a light stabilizer as component (G). [8] The transparent resin composition according to any one of [1] to [7] above, wherein the average value of the total light transmittance of a 60-μm-thick transparent resin composition layer formed from the transparent resin composition is 80% or more at a wavelength of 380 to 780 nm. [9] The transparent resin composition according to any one of [1] to [8] above, wherein the haze of a 60-μm-thick transparent resin composition layer formed from the transparent resin composition is 5% or less.

[10] A resin sheet having a laminated structure including a support and a transparent resin composition layer formed from the transparent resin composition according to any one of [1] to [9] above.

[11] The resin sheet according to

[10] above, wherein the average value of the total light transmittance of the transparent resin composition layer is 80% or more at a wavelength of 380 to 780 nm.

[12] The resin sheet according to

[10] or

[11] , wherein the haze of the transparent resin composition layer is 5% or less.

[13] An electronic device including a cured product layer formed from the transparent resin composition according to any one of [1] to [9].

Advantages of the Invention

[0007] According to the present invention, a transparent resin composition capable of forming a cured product excellent in warpage suppression and yellowing resistance can be obtained.

Embodiments for Carrying Out the Invention

[0008] The present invention relates to the following components (A) to (C): (A) An epoxy resin having a fluoroalkyl group and / or an alicyclic structure, (B) A phosphite antioxidant, and (C) A curing accelerator A transparent resin composition containing the same is provided. Unless otherwise specified, in the present invention, each component may be used alone or in combination of two or more. Hereinafter, components (A) to (C) will be described in order.

[0009] <(A) An epoxy resin having a fluoroalkyl group and / or an alicyclic structure> The transparent resin composition of the present invention contains, as component (A), an epoxy resin having a fluoroalkyl group and / or an alicyclic structure. A cured product excellent in yellowing resistance can be formed from the resin composition containing component (A). Component (A) is preferably an epoxy resin having two or more epoxy groups in one molecule and having a fluoroalkyl group and / or an alicyclic structure.

[0010] In this specification, the "epoxy resin" means a thermosetting resin having an epoxy group and an epoxy equivalent of 5,000 g / eq or less. Here, the epoxy equivalent means the number of grams of a resin containing 1 gram equivalent of epoxy groups (unit: g / eq). In other words, the epoxy equivalent means the value obtained by dividing the molecular weight of the resin by the number of epoxy groups the resin has, that is, the molecular weight per epoxy group. The epoxy equivalent is measured according to the method specified in JIS K 7236.

[0011] From the viewpoint of the yellowing resistance of the cured product, the fluoroalkyl group that component (A) may have is preferably C 1-6 fluoroalkyl group, more preferably C 1-6 perfluoroalkyl group, and particularly preferably trifluoromethyl group.

[0012] In this specification, "C x-y "(x and y: integers) means that the number of carbon atoms is from x to y. In this specification, the "fluoroalkyl group" means an alkyl group substituted with a fluorine atom, and the "perfluoroalkyl group" means an alkyl group in which all hydrogen atoms are substituted with fluorine atoms.

[0013] In this specification, examples of the "C 1-6 fluoroalkyl group" include, for example, fluoromethyl group, difluoromethyl group, perfluoromethyl group (i.e., trifluoromethyl group), 2-fluoroethyl group, 2,2,2-trifluoroethyl group, perfluoroethyl group, 2,2-difluoropropyl group, perfluoropropyl group, perfluorobutyl group, perfluoropentyl group, perfluorohexyl group.

[0014] In this specification, examples of the "C 1-6 perfluoroalkyl group" include those that are perfluoroalkyl groups among the examples of the above "C 1-6 fluoroalkyl group".

[0015] The alicyclic structure that component (A) may have is preferably a C 3-12 alicyclic structure from the viewpoint of the yellowing resistance of the cured product. The alicyclic structure may be any of a monocyclic structure, a bicyclic structure, a condensed polycyclic structure, and a condensed polycyclic structure containing a bicyclic ring. Component (A) may have one kind of alicyclic structure or two or more kinds of alicyclic structures. The alicyclic structure that component (A) may have is more preferably a C 3-8 cycloalkane ring structure and / or dicyclopentadiene ring structure. In this specification, the "C 3-8 cycloalkane ring" includes, for example, a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, and a cyclooctane ring. The alicyclic structure that component (A) may have is even more preferably a C 5-6 cycloalkane ring structure (i.e., cycloheptane ring structure, cyclohexane ring structure), and particularly preferably a cyclohexane ring structure.

[0016] Component (A) is more preferably an epoxy resin having at least one selected from the group consisting of a fluoroalkyl group, a C 3-8 cycloalkane ring structure, and a dicyclopentadiene ring structure.

[0017] Examples of the epoxy resin having a fluoroalkyl group include bisphenol AF type epoxy resin having a trifluoromethyl group. Also, the fluorine-containing epoxy resin described in WO2011 / 089947 can also be used as an epoxy resin having a fluoroalkyl group. In this specification, the "X type epoxy resin" (example of X: bisphenol AF) means an epoxy resin having a structure derived from X as is well known in the field of epoxy resins.

[0018] Examples of the epoxy resin having an alicyclic structure include bisphenol TMC type epoxy resin having a cyclohexane ring structure, bisphenol Z type epoxy resin having a cyclohexane ring structure, dicyclopentadiene type epoxy resin, and the like. Further, an epoxy resin having a cyclohexane ring structure other than bisphenol TMC type epoxy resin and bisphenol Z type epoxy resin (for example, "EHPE3150" manufactured by Daicel Corporation) can also be used as the component (A).

[0019] From the viewpoint of the yellowing resistance of the cured product, the component (A) (i) is preferably an epoxy resin having a fluoroalkyl group and / or an epoxy resin having an alicyclic structure, (ii) more preferably at least one selected from the group consisting of an epoxy resin having a C 1-6 fluoroalkyl group, an epoxy resin having a C 3-8 cycloalkane ring structure, and an epoxy resin having a dicyclopentadiene ring structure, (iii) even more preferably an epoxy resin having a C 1-6 perfluoroalkyl group, an epoxy resin having a C 5-6 cycloalkane ring structure, or an epoxy resin having a dicyclopentadiene ring structure, (iv) still more preferably an epoxy resin having a trifluoromethyl group, an epoxy resin having a cyclohexane ring structure, or an epoxy resin having a dicyclopentadiene ring structure, (v) particularly preferably a bisphenol AF type epoxy resin, an epoxy resin having a cyclohexane ring structure, or an epoxy resin having a dicyclopentadiene ring structure.

[0020] Component (A) may be a commercially available product or a product manufactured by a known method (for example, the reaction of bisphenol AF, bisphenol TMC or bisphenol Z with epichlorohydrin). Examples of commercially available products include "YX7760", "YX8000", "YX8034" manufactured by Mitsubishi Chemical Corporation, "EHPE3150", "EHPE3150CE", "Celloxide 2021P", "Celloxide 2081P", "Celloxide 2000", "Celloxide 8000" manufactured by Daicel Corporation, "HP-7200", "HP-7200L", "HP-7200H" manufactured by DIC Corporation, "XD-1000" manufactured by Nippon Kayaku Co., Ltd., "Denacol EX-252" manufactured by Nagase ChemteX Corporation, "Sho-Free CDMDG" manufactured by Showa Denko K.K., "THI-DE", "DE-102", "DE-103" manufactured by ENEOS Corporation, "DCPD-DE" manufactured by Nippon Materials Technology Co., Ltd., "KR-470" manufactured by Shin-Etsu Chemical Co., Ltd., "LDO" manufactured by SYMERISE, "EP-4088S" manufactured by ADEKA Corporation, etc.

[0021] From the viewpoint of the adhesion strength of the cured product, the epoxy equivalent of component (A) is preferably 50 to 5,000 g / eq, more preferably 80 to 2,000 g / eq, and still more preferably 100 to 1,500 g / eq.

[0022] From the viewpoint of the yellowing resistance of the cured product, the content of component (A) is preferably 20 to 94% by mass, more preferably 40 to 89% by mass, and still more preferably 50 to 84% by mass based on the non-volatile content of the transparent resin composition. When a plurality of component (A) is used, the content means the total content of the plurality of component (A). Regarding the content of components other than component (A), when a plurality of such components are used, the content means the total content of the components.

[0023] Component (A) may be used alone or in combination of two or more. Further, component (A) may be in solid form or in liquid form. In this specification, "solid form" means having no fluidity under room temperature (25 °C) and atmospheric pressure (0.1 MPa), and "liquid form" means having fluidity under room temperature (25 °C) and atmospheric pressure (0.1 MPa). "Liquid form" preferably has a viscosity of 2,000 Pa·s or less, more preferably 1,500 Pa·s or less, still more preferably 1,200 Pa·s or less at 25 °C under atmospheric pressure. The viscosity can be measured using an E-type viscometer at 25 °C under atmospheric pressure and a cone rotation speed of 0.5 rpm. Examples of the E-type viscometer include E-type viscometer: RE-85U (cone rotor: 3°×R9.7) (manufactured by Toki Sangyo Co., Ltd.).

[0024] From the viewpoint of the flexibility of the transparent resin composition layer formed by the transparent resin composition and its cured product, when a solid component is used as component (A), it is preferable to use a liquid component in combination with component (A), or to further contain a liquid epoxy resin (component (D)) having neither a fluoroalkyl group nor an alicyclic structure as described below. In this case, the mass ratio of the solid component (A) to the liquid component (A) and / or component (D) (solid component (A): liquid component (A) and / or component (D)) is preferably 1:5 to 1:0.05, more preferably 1:4 to 1:0.1, still more preferably 1:3 to 1:0.2, and particularly preferably 1:2 to 1:0.3.

[0025] <(B) Phosphite-based antioxidant> The transparent resin composition of the present invention contains a phosphite-based antioxidant as component (B). By using component (B), it is possible to reduce the warpage of the cured product while maintaining the excellent yellowing resistance of the cured product obtained from the resin composition containing component (A).

[0026] Examples of phosphite antioxidants include tris(nonylphenyl) phosphite, triphenyl phosphite, tridecyl phosphite, trioctadecyl phosphite, tris(2,4-di-t-butylphenyl) phosphite (trade name "Irgafos 168" manufactured by BASF, etc.), bis(2,4-di-t-butylphenyl)pentaerythritol-diphosphite (trade name "Irgafos 126" manufactured by BASF, trade name "Adekastab PEP-24G" manufactured by ADEKA, etc.), bis(2,4-di-t-butyl-6-methylphenyl)ethyl phosphite (trade name "Irgafos 38" manufactured by BASF, etc.), 3,9-bis(2,6-di-t-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (trade name "Adekastab PEP-36" manufactured by ADEKA, etc.), distearyl-pentaerythritol-diphosphite (trade name "Adekastab PEP-8" manufactured by ADEKA, trade name "JPP-2000" manufactured by Johoku Chemical Co., Ltd., etc.), [bis(2,4-di-t-butyl-5-methylphenoxy)phosphino]biphenyl (trade name "GSY-P101" manufactured by Osaki Kogyo Co., Ltd., etc.), 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenz[d,f][1,3,2]dioxaphosphepine (trade name "Sumilizer GP" manufactured by Sumitomo Chemical Co., Ltd., etc.), N,N-bis[2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenz[d,f][1,3,2]dioxaphosphepin-6-yl]oxy]-ethyl]ethanamine (trade name "Irgafos 12" manufactured by BASF, etc.), hydrogenated bisphenol A·pentaerythritol phosphite polymer (trade name "JPH-3800" manufactured by Johoku Chemical Co., Ltd.), 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite) (trade name "JPH-1200" manufactured by Johoku Chemical Co., Ltd.), and the like.

[0027] From the viewpoint of the transparency of the resin composition, the component (B) is preferably a phosphite antioxidant having a bisphenol structure or a hydrogenated bisphenol structure. The phosphite antioxidant having a bisphenol structure or a hydrogenated bisphenol structure has excellent compatibility with the component (A), and the resin composition containing such a phosphite antioxidant as the component (B) has good transparency. Examples of the phosphite antioxidant having a structure derived from bisphenols include 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite) (trade name "JPH-1200" manufactured by Johoku Chemical Industry Co., Ltd.), 4,4'-isopropylidenediphenol C 12 - 15 alcohol phosphite (trade name "ADEKA STAB 1500" manufactured by ADEKA Corporation), 2,2'-methylenebis(4,6-di-t-butylphenyl) 2-ethylhexyl phosphite (trade name "ADEKA STAB HP-10" manufactured by ADEKA Corporation), and the like. Examples of the phosphite antioxidant having a hydrogenated bisphenol structure include hydrogenated bisphenol A·pentaerythritol phosphite polymer (trade name "JPH-3800" manufactured by Johoku Chemical Industry Co., Ltd.), and the like.

[0028] From the viewpoints of suppressing warpage of the cured product and flexibility of the cured product, the content of the component (B) is preferably 0.1 to 10% by mass, more preferably 0.3 to 5% by mass, and still more preferably 1 to 3% by mass based on the non-volatile content of the transparent resin composition.

[0029] <(C) Curing accelerator> The transparent resin composition of the present invention contains a curing accelerator as the component (C). In this specification, the "curing accelerator" means an additive that promotes the curing reaction between the components (A) (i.e., epoxy resins having a fluoroalkyl group and / or an alicyclic structure). In the field of epoxy, an additive that promotes the curing reaction between epoxy resins is sometimes called a curing agent (especially a catalyst-type curing agent).

[0030] Examples of the curing accelerator include phosphorus-based curing accelerators (e.g., phosphonium salts, phosphines), imidazole-based curing accelerators, amine-based curing accelerators, guanidine-based curing accelerators, and metal-based curing accelerators.

[0031] Examples of the phosphonium salt include phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate. Commercially available phosphonium salts can be used. Examples of such commercially available products include "TBP-DA" manufactured by Hokko Chemical Industry Co., Ltd.

[0032] Examples of the phosphine include triphenylphosphine, tricyclohexylphosphine, tributylphosphine, and methyldiphenylphosphine.

[0033] Examples of imidazole-based curing accelerators include imidazole compounds such as 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, and adducts of imidazole compounds and epoxy resins. As the imidazole-based curing accelerator, commercially available products can be used. Examples of such commercially available products include "P200-H50" manufactured by Mitsubishi Chemical Corporation and "1B2PZ-10M" manufactured by Shikoku Kasei Kogyo Co., Ltd.

[0034] Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, and the like.

[0035] Examples of guanidine-based curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, 1-(o-tolyl)biguanide, and the like.

[0036] Examples of metal-based curing accelerators include organometallic complexes or organometallic salts in which the metal is cobalt, copper, zinc, iron, nickel, manganese, or tin. Examples of organometallic complexes include organocobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organocopper complexes such as copper(II) acetylacetonate, organozinc complexes such as zinc(II) acetylacetonate, organoiron complexes such as iron(III) acetylacetonate, organonickel complexes such as nickel(II) acetylacetonate, and organomanganese complexes such as manganese(II) acetylacetonate. Examples of organometallic salts include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0037] From the viewpoints of the heat curability and storage stability of the resin composition, the content of component (C) is preferably 0.1 to 5% by mass, more preferably 0.3 to 4% by mass, and still more preferably 0.5 to 3% by mass based on the nonvolatile content of the transparent resin composition.

[0038] From the viewpoint of the yellowing resistance of the cured product, it is preferable to use a phosphonium salt as the curing accelerator. The content of the phosphonium salt in the transparent resin composition of the present invention is preferably 90 to 100% by mass, more preferably 95 to 100% by mass based on the whole of component (C). From the viewpoint of the yellowing resistance of the cured product, it is most preferable that component (C) is a phosphonium salt, that is, the whole of component (C) consists of a phosphonium salt.

[0039] <Other components> The transparent resin composition of the present invention may contain components other than components (A) to (C) (which may be described as "other components" in this specification) as long as the effects of the present invention are not inhibited. Examples of other components include a liquid epoxy resin (component (D)) having neither a fluoroalkyl group nor an alicyclic structure, a high molecular compound (including a phenoxy resin (component (E))), an epoxy resin other than components (A) and (D), an organic solvent, a silane coupling agent (component (F)), an ultraviolet absorber, and a light stabilizer (component (G)). Any of the other components may be used alone or in combination of two or more. Hereinafter, these other components will be described in order.

[0040] ((D) A liquid epoxy resin having neither a fluoroalkyl group nor an alicyclic structure) The transparent resin composition of the present invention may contain, as component (D), a liquid epoxy resin having neither a fluoroalkyl group nor an alicyclic structure (which may be referred to as "component (D)" or "liquid epoxy resin" in this specification). As described above, from the viewpoint of the flexibility of the transparent resin composition layer formed by the transparent resin composition and its cured product, particularly when only an epoxy resin having a solid fluoroalkyl group and / or an alicyclic structure is used as component (A), the transparent resin composition of the present invention preferably further contains a liquid epoxy resin.

[0041] As the liquid epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule is preferable. As the liquid epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin having an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, and epoxy resin having a butadiene structure are preferable.

[0042] Specific examples of the liquid epoxy resin include "HP4032", "HP4032D", "HP4032SS" (naphthalene-type epoxy resin) manufactured by DIC Corporation; "828US", "828EL", "jER828EL", "825", "Epicoat 828EL" (bisphenol A-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER807", "1750" (bisphenol F-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER152" (phenol novolac-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "630", "630LSD", "604" (glycidylamine-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "ED-523T" (glycerol-type epoxy resin) manufactured by ADEKA Corporation; "EP-3950L", "EP-3980S" (glycidylamine-type epoxy resin) manufactured by ADEKA Corporation; "ZX1059" (a mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; "EX-721" (glycidyl ester-type epoxy resin) manufactured by Nagase ChemteX Corporation; "PB-3600" manufactured by Daicel Corporation, "JP-100", "JP-200" (epoxy resin having a butadiene structure) manufactured by Nippon Soda Co., Ltd., and the like. These may be used alone or in combination of two or more.

[0043] From the viewpoint of the adhesion strength of the cured product, the epoxy equivalent of the liquid epoxy resin is preferably 50 to 5,000 g / eq, more preferably 80 to 2,000 g / eq, and still more preferably 100 to 1,500 g / eq.

[0044] When the solid component (A) is used in combination with the liquid component (A) and / or component (D), from the viewpoint of the flexibility of the transparent resin composition layer formed by the transparent resin composition and its cured product, the mass ratio of the solid component (A) to the liquid component (A) and / or component (D) (solid component (A): liquid component (A) and / or component (D)) is preferably 1:5 to 1:0.05, more preferably 1:4 to 1:0.1, still more preferably 1:3 to 1:0.2, and particularly preferably 1:2 to 1:0.3.

[0045] (Polymer compound) In order to form a film of the transparent resin composition of the present invention, it preferably contains a high molecular compound. In this specification, the "high molecular compound" means a compound having a weight average molecular weight (hereinafter sometimes referred to as "Mw") of 1,000 or more. This Mw can be measured by gel permeation chromatography (GPC).

[0046] Examples of the high molecular compound include phenoxy resin, polyester polyol, polyether polyol, polycarbonate polyol, (meth)acrylic resin, etc. The preferred Mw of the phenoxy resin will be described later. The Mw of the polyester polyol is preferably 1,000 to 10,000. The Mw of the polyether polyol is 1,000 to 10,000. The Mw of the polycarbonate polyol is 1,000 to 10,000. The Mw of the (meth)acrylic resin is preferably 1,000 to 500,000.

[0047] The high molecular compound is preferably a phenoxy resin (sometimes referred to as "component (E)" in this specification). In this specification, the "phenoxy resin" means a high molecular weight polyhydroxy polyether having a structure derived from bisphenols. Examples of the phenoxy resin include those obtained by the reaction of bisphenols and epichlorohydrin, and those obtained by the reaction of bisphenol type epoxy resins. Here, the "bisphenol type epoxy resin" means an epoxy resin having a structure derived from bisphenols (for example, bisphenol AF). Note that the phenoxy resin may have a structure other than the structure derived from bisphenols.

[0048] The phenoxy resin may or may not have an epoxy group. In the present invention, "phenoxy resin having an epoxy group" and "epoxy resin" are distinguished by epoxy equivalent. That is, in the present invention, those with an epoxy equivalent exceeding 5000 g / eq are classified as "phenoxy resin having an epoxy group", and those with an epoxy equivalent of 5000 g / eq or less are classified as "epoxy resin". From the viewpoints of film formation of the transparent resin composition and adhesion strength of the cured product, the epoxy equivalent of the phenoxy resin having an epoxy group is preferably more than 5,000 g / eq and 40,000 g / eq or less, more preferably 7,000 to 35,000 g / eq, and still more preferably 8,000 to 30,000 g / eq.

[0049] From the viewpoints of compatibility in the transparent resin composition and adhesion strength of the cured product, the weight average molecular weight of the phenoxy resin is preferably more than 10,000 and 100,000 or less, more preferably 20,000 to 80,000, and still more preferably 25,000 to 60,000.

[0050] Commercially available products of the phenoxy resin may be used, or those produced by known methods (for example, the reaction of bisphenols and epichlorohydrin) may be used. Examples of commercially available products include "YX7200B35", "1256", "4250", "YX8100", "YX6954BH30", "YX7553BH30", "YL7769BH30", "YX7876B40", "YL9008B40", "YL6794", "YL7213", "YL7891BH30", "YL7482" manufactured by Mitsubishi Chemical Corporation, and "YP-50", "YP-70S", "FX-293", "FX280S" manufactured by Nippon Steel Chemical & Material Co., Ltd.

[0051] From the viewpoint of yellowing resistance of the cured product, the phenoxy resin (i) is preferably a phenoxy resin having a fluoroalkyl group and / or a phenoxy resin having an alicyclic structure, (ii) more preferably a C 1-6 phenoxy resin having a fluoroalkyl group, C 3-8At least one selected from the group consisting of a phenoxy resin having a cycloalkane ring structure and a phenoxy resin having a dicyclopentadiene ring structure, (iii) More preferably C 1-6 A phenoxy resin having a perfluoroalkyl group, C 5-6 A phenoxy resin having a cycloalkane ring structure, or a phenoxy resin having a dicyclopentadiene ring structure, (iv) Even more preferably a phenoxy resin having a trifluoromethyl group, a phenoxy resin having a cyclohexane ring structure, or a phenoxy resin having a dicyclopentadiene ring structure, (v) Particularly preferably a bisphenol AF type phenoxy resin, a phenoxy resin having a cyclohexane ring structure, or a phenoxy resin having a dicyclopentadiene ring structure. In the present specification, the "bisphenol AF type phenoxy resin" means a phenoxy resin having a structure derived from bisphenol AF.

[0052] When using a polymer compound, its content is preferably 5 to 50% by mass, more preferably 7.5 to 45% by mass, and even more preferably 10 to 40% by mass with respect to the non-volatile content of the transparent resin composition, from the viewpoints of film formation of the transparent resin composition and adhesion strength of the cured product.

[0053] When using a phenoxy resin as component (E), its content is preferably 5 to 50% by mass, more preferably 7.5 to 45% by mass, and even more preferably 10 to 40% by mass with respect to the non-volatile content of the transparent resin composition, from the viewpoints of film formation of the transparent resin composition and adhesion strength of the cured product.

[0054] (Epoxy resin other than component (A) and component (D)) The transparent resin composition of the present invention may contain an epoxy resin other than component (A) and component (D) (which may be referred to as "other epoxy resin" in the present specification) as long as the effects of the present invention are not inhibited. Only one kind of other epoxy resin may be used, or two or more kinds may be used in combination.

[0055] As other epoxy resins, there is no particular limitation, and known epoxy resins can be used. Examples of other epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, biphenyl alkyl type epoxy resin, naphthol type epoxy resin, and naphthalene type epoxy resin. As other epoxy resins, a mixture of multiple types of epoxy resins (for example, a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) may be used.

[0056] From the viewpoint of the adhesion strength of the cured product of the transparent resin composition, the epoxy equivalent of other epoxy resins is preferably 50 to 5,000 g / eq, more preferably 80 to 2,000 g / eq, and still more preferably 100 to 1,500 g / eq.

[0057] From the viewpoint of the yellowing resistance of the cured product, the transparent resin composition of the present invention does not contain other epoxy resins, or contains other epoxy resins in a content of 50% by mass or less based on the total of other epoxy resins and component (A) (when component (D) is used, this is also included. The same applies hereinafter). That is, it is preferable to limit the content of other epoxy resins to 50% by mass or less based on the total of other epoxy resins and component (A). The content of other epoxy resins is more preferably 30% by mass or less, and still more preferably 20% by mass or less based on the total of other epoxy resins and component (A).

[0058] (Organic solvent) The transparent resin composition of the present invention may contain an organic solvent. That is, the transparent resin composition of the present invention may be a varnish-like transparent resin composition containing an organic solvent.

[0059] Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone (MEK, 2-butanone), and cyclohexanone; acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; cellosolves such as cellosolve; carbitols such as butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide, dimethylacetamide, and N-methylpyrrolidone.

[0060] When using an organic solvent, its content is preferably 5 to 50% by mass, more preferably 10 to 45% by mass, and still more preferably 15 to 40% by mass based on the total amount of the transparent resin composition.

[0061] ((F) Silane coupling agent) From the viewpoint of the adhesion strength of the cured product to glass, the transparent resin composition of the present invention preferably further contains a silane coupling agent (which may be referred to as "component (F)" in this specification). In addition, although the cured product obtained from the resin composition containing component (A) tends to have a reduced fracture toughness, the fracture toughness of the cured product can be improved by using component (F). Component (F) is selected from the group consisting of (meth)acryloyl group-containing silane coupling agents, epoxy group-containing silane coupling agents, and vinyl group-containing silane coupling agents.

[0062] Examples of the (meth)acryloyl group-containing silane coupling agent include 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropylmethyldimethoxysilane 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 8-methacryloxyoctyltrimethoxysilane.

[0063] Examples of the epoxy group-containing silane coupling agent include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, and 8-glycidoxyoctyltrimethoxysilane.

[0064] Examples of the vinyl group-containing silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, and 7-octenyltrimethoxysilane.

[0065] As the component (F), commercially available products can be used. Examples of such commercially available products include "KBM-5103", "KBM-502", "KBM-503", "KBE-502", "KBE-503", "KBM-5803", "KBM-303", "KBM-402", "KBM-403", "KBE-402", "KBE-403", "KBM-4803", "KBM-1003", "KBE-1003", and "KBM-1083" manufactured by Shin-Etsu Chemical Co., Ltd.

[0066] From the viewpoint of the adhesion strength of the cured product, the component (F) is preferably at least one selected from the group consisting of 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 8-methacryloxyoctyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, vinyltrimethoxysilane, and 7-octenyltrimethoxysilane.

[0067] In order to suppress the occurrence of warping due to the shrinkage during curing of the transparent resin composition, the component (F) is preferably an epoxy group-containing silane coupling agent and / or a (meth)acryloyl group-containing silane coupling agent.

[0068] From the viewpoint of the adhesion strength of the cured product, the content of component (F) is preferably 0.1 to 20% by mass, more preferably 0.75 to 15% by mass, and still more preferably 1.0 to 10% by mass based on the non-volatile content of the transparent resin composition.

[0069] Depending on the type of silane coupling agent used (for example, a mercapto group-containing silane coupling agent), the storage stability of the transparent resin composition may decrease. However, in the present invention, by using at least one selected from the group consisting of a (meth)acryloyl group-containing silane coupling agent, an epoxy group-containing silane coupling agent, and a vinyl group-containing silane coupling agent as component (F), the storage stability can be made good.

[0070] From the viewpoint of storage stability, the transparent resin composition of the present invention does not contain a silane coupling agent other than component (F) (which may be described as "other silane coupling agent" in this specification), or contains the other silane coupling agent in a content of 25% by mass or less based on the total of the other silane coupling agent and component (F) (that is, the content of the other silane coupling agent is limited to 25% by mass or less based on the total of the other silane coupling agent and component (F)). The content of the other silane coupling agent is more preferably 15% by mass or less, and still more preferably 10% by mass or less based on the total of the other silane coupling agent and component (F).

[0071] ((G) Light stabilizer) The transparent resin composition of the present invention preferably further contains a light stabilizer (which may be described as "component (G)" in this specification) from the viewpoint of improving the yellowing resistance. Examples of the light stabilizer include hindered amine light stabilizers. Examples of hindered amine light stabilizers include bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-2-butyl-2-(4-hydroxy-3,5-di-t-butylbenzyl) propanedioate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidinyl) butane-1,2,3,4-tetracarboxylate, tetrakis(2,2,6,6-tetramethyl-4-piperidinyl) butane-1,2,3,4-tetracarboxylate, a mixed ester of butane-1,2,3,4-tetracarboxylic acid with 1,2,2,6,6-pentamethyl-4-piperidinol and 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, and bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate.

[0072] Commercially available products can be used as the light stabilizer. Examples of such commercially available products include "Tinuvin 770 DF" and "Tinuvin PA 144" manufactured by BASF, and "ADEKA STAB LA-52", "ADEKA STAB LA-57", "ADEKA STAB LA-63P", "ADEKA STAB LA-68", "ADEKA STAB LA-72", "ADEKA STAB LA-81", and "ADEKA STAB LA-87" manufactured by ADEKA.

[0073] From the viewpoint of improving yellowing resistance, the content of component (G) is preferably 0.1 to 10% by mass, more preferably 0.5 to 8% by mass, and still more preferably 1 to 5% by mass based on the non-volatile content of the transparent resin composition.

[0074] (Ultraviolet absorber) Examples of the ultraviolet absorber include benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, salicylic acid-based ultraviolet absorbers, and triazine-based ultraviolet absorbers.

[0075] Examples of benzophenone-based ultraviolet absorbers include 2-hydroxy-4-octyloxybenzophenone, 2,4-dihydroxy-benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2-hydroxy-4-n-octyl-benzophenone, 2-hydroxy-4-n-dodecyloxy-benzophenone, bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane, 2,2'-dihydroxy-4-methoxy-benzophenone, and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone.

[0076] Examples of benzotriazole-based ultraviolet absorbers include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-[2'-hydroxy-3',5'-bis(α,α-dimethylbenzyl)phenyl]-benzotriazole, 2-(2'-hydroxy-3',5-di-tert-butylphenyl)-benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-amyl)benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, and 2,2-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol].

[0077] Examples of salicylic acid-based UV absorbers include phenyl salicylate, 4-tert-butylphenyl-2-hydroxybenzoate, phenyl-2-hydroxybenzoate, 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate, ethylene-2-cyano-3,3'-diphenyl acrylate, 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone.

[0078] Examples of triazine-based UV absorbers include 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-hexyloxyphenol, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]phenol, 2-[4,6-bis(dimethylphenyl)-1,3,5-triazin-2-yl]-5-「3-[(2-ethylhexyl)oxy]-2-hydroxypropoxy」-phenol, 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine.

[0079] Commercially available products can be used as the ultraviolet absorber. Examples of such commercially available products include "Chimassorb 81 FL", "Tinuvin P", "Tinuvin 213", "Tinuvin 234", "Tinuvin 326", "Tinuvin 360", "Tinuvin 571", "Tinuvin 1577 ED", "Tinuvin 120" manufactured by BASF; "EVERSORB 11", "EVERSORB 12", "EVERSORB 40", "EVERSORB 71", "EVERSORB 73", "EVERSORB 78", "EVERSORB 80", "EVERSORB 109" manufactured by Sanyo Trading Co., Ltd.; "5405" manufactured by Kusumoto Chemical Co., Ltd.; "ADEKA STAB LA-46", "ADEKA STAB LA-F70" manufactured by ADEKA.

[0080] From the viewpoint of improving yellowing resistance, the content of the ultraviolet absorber is preferably 0.1 to 10% by mass, more preferably 0.5 to 8% by mass, and still more preferably 1 to 5% by mass based on the non-volatile content of the transparent resin composition.

[0081] (Inorganic filler) The transparent resin composition of the present invention may contain an inorganic filler as long as the transparency is maintained. From the viewpoint of the transparency of the cured product, the transparent resin composition of the present invention preferably does not contain an inorganic filler or contains the inorganic filler in an amount of 30% by mass or less based on the non-volatile content of the transparent resin composition (that is, the content of the inorganic filler is limited to 30% by mass or less based on the non-volatile content of the transparent resin composition). The content of the inorganic filler is more preferably 20% by mass or less, still more preferably 10% by mass or less, and particularly preferably 5% by mass or less based on the non-volatile content of the transparent resin composition.

[0082] <Average value of the total light transmittance of the transparent resin composition layer with a thickness of 60 μm in the wavelength range of 380 to 780 nm> The average value of the total light transmittance of the transparent resin composition layer with a thickness of 60 μm formed from the transparent resin composition of the present invention at wavelengths of 380 to 780 nm is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. This average value can be measured by the method described in the Examples section below.

[0083] <Average value of the total light transmittance of the cured product layer with a thickness of 60 μm at wavelengths of 380 to 780 nm> The average value of the total light transmittance of the cured product layer with a thickness of 60 μm formed from the transparent resin composition of the present invention at wavelengths of 380 to 780 nm is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. This average value can be measured by the method described in the Examples section below.

[0084] <Haze (%) of the transparent resin composition layer with a thickness of 60 μm> The haze (%) of the transparent resin composition layer with a thickness of 60 μm formed from the transparent resin composition of the present invention is preferably 5% or less, more preferably 4% or less, and even more preferably 3% or less. This haze can be measured by the method described in the Examples section below.

[0085] <Haze (%) of the cured product layer with a thickness of 60 μm> The haze (%) of the cured product layer with a thickness of 60 μm formed from the transparent resin composition of the present invention is preferably 5% or less, more preferably 4% or less, and even more preferably 3% or less. This haze can be measured by the method described in the Examples section below.

[0086] <Resin sheet> The present invention also provides a resin sheet having a laminated structure including a support and a transparent resin composition layer formed from the transparent resin composition of the present invention. A protective film may be used in the present invention. That is, the resin sheet of the present invention may have a laminated structure including a support, a transparent resin composition layer, and a protective film in this order. Other layers (for example, a release layer, an adhesive layer) may be present between the support and the transparent resin composition layer and between the transparent resin composition layer and the protective film.

[0087] The thickness of the transparent resin composition layer is not particularly limited, but the thickness is preferably 1 μm or more, more preferably 1.5 μm or more, still more preferably 2 μm or more, particularly preferably 5 μm or more, and preferably 150 μm or less, preferably 120 μm or less, more preferably 100 μm or less, still more preferably 80 μm or less.

[0088] Examples of the support include plastic films such as polyethylene, polypropylene, polyvinyl chloride, cycloolefin polymer, polyethylene terephthalate (hereinafter sometimes abbreviated as "PET"), polyethylene naphthalate, polycarbonate, and polyimide, and metal foils such as aluminum foil, stainless steel foil, and copper foil. Among them, polyethylene terephthalate and polyethylene naphthalate are preferable, and inexpensive polyethylene terephthalate is particularly preferable. The support may have a release layer on the surface that joins with the transparent resin composition layer. Examples of the release agent for forming the release layer include silicone resin-based release agents, alkyd resin-based release agents, and fluororesin-based release agents. The support may be subjected to a mat treatment, a corona treatment, or an antistatic treatment on the surface that joins with the transparent resin composition layer.

[0089] The thickness of the support is not particularly limited, but the thickness is preferably 5 to 75 μm, more preferably 10 to 60 μm. When using a support with a release layer, it is preferable that the total thickness of the support with the release layer is within the above range.

[0090] The resin sheet can be produced, for example, by (1) producing a varnish-like transparent resin composition, (2) applying this onto a support using a die coater or the like to form a coating film, and (3) drying the obtained coating film to form a transparent resin composition layer. The method for producing the varnish-like transparent resin composition is not particularly limited, and it can be produced by mixing an organic solvent and each component using a known device such as a rotary mixer.

[0091] Drying of the coating film can be carried out by known methods such as heating and hot air blowing. The drying conditions are not particularly limited. It is preferable to perform drying until the content of the organic solvent in the transparent resin composition layer becomes 10% by mass or less. The content of the organic solvent in the dried transparent resin composition layer is more preferably 5% by mass or less. The drying time and drying temperature vary depending on the content of the organic solvent in the varnish-like transparent resin composition and its boiling point. The drying temperature is, for example, about 50 to 150°C, and the drying time is, for example, about 3 to 10 minutes.

[0092] The resin sheet can be wound into a roll for storage. When the resin sheet has a protective film, the resin sheet can be used by peeling off the protective film.

[0093] The average value of the total light transmittance of the transparent resin composition layer of the resin sheet of the present invention at wavelengths of 380 to 780 nm is preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more, regardless of the thickness of the transparent resin composition layer. This average value can be measured by the method described in the Examples section below. The haze (%) of the transparent resin composition layer of the resin sheet of the present invention is preferably 5% or less, more preferably 4% or less, and still more preferably 3% or less, regardless of the thickness of the transparent resin composition layer. This haze can be measured by the method described in the Examples section below.

[0094] <Electronic device> The present invention also provides an electronic device including a cured product layer formed of the transparent resin composition of the present invention. Examples of the electronic device include an LED device and a transparent FPC.

[0095] The average value of the total light transmittance of the cured product layer of the electronic device of the present invention at wavelengths of 380 to 780 nm is preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more, regardless of the thickness of the cured product layer. This average value can be measured by the method described in the Examples section below. The haze (%) of the cured product layer of the electronic device of the present invention is preferably 5% or less, more preferably 4% or less, and even more preferably 3% or less, regardless of the thickness of the cured product layer. This haze can be measured by the method described in the Examples section below.

[0096] The cured product layer is preferably formed by heating a transparent resin composition layer. The heating method is not particularly limited, and the transparent resin composition layer can be heated by known equipment (for example, a hot air circulation oven, an infrared heater, a heat gun, a high frequency induction heating device). From the viewpoint of promoting the curing reaction, the curing temperature is preferably 100 °C or higher, more preferably 120 °C or higher, and from the viewpoint of preventing coloring of the cured product layer, it is preferably 210 °C or lower, more preferably 190 °C or lower. Also, the curing time is preferably 10 minutes or longer, more preferably 20 minutes or longer, and preferably 180 minutes or shorter, more preferably 120 minutes or shorter.

Examples

[0097] Hereinafter, the present invention will be described more specifically with reference to Examples. However, the present invention is not limited by the following Examples, and it is also possible to appropriately modify and implement within the range that conforms to the above and below gists, and all of them are included in the technical scope of the present invention. In addition, "parts" and "% " in the amounts of the components mean "parts by mass" and "mass%", respectively, unless otherwise specified.

[0098] The components used in the Examples and Comparative Examples are shown below. <Component (A): Epoxy resin having a fluoroalkyl group and / or an alicyclic structure> "YX7760" (manufactured by Mitsubishi Chemical Corporation, bisphenol AF type epoxy resin, solid, epoxy equivalent: 245 g / eq) "EHPE3150" (manufactured by Daicel Corporation, epoxy resin having a cyclohexane ring structure (1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol), solid, epoxy equivalent: 180 g / eq) "EP-4088S" (manufactured by ADEKA, dicyclopentadiene dimethanol type epoxy resin, liquid (viscosity at 25°C: 230 mPa·s), epoxy equivalent: 170 g / eq)

[0099] <Component (D): A liquid epoxy resin having neither a fluoroalkyl group nor an alicyclic structure (abbreviated as "liquid epoxy resin")> "ZX1059" (a mixture of bisphenol A type epoxy resin (50%) and bisphenol F type epoxy resin (50%) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., liquid (viscosity at 25°C: 2,000 mPa·s), epoxy equivalent: 165 g / eq)

[0100] <Component (B): A phosphite-based antioxidant> "JPH-3800" (manufactured by Johoku Chemical Industry Co., Ltd., hydrogenated bisphenol A·pentaerythritol phosphite polymer, CAS number: 101320-77-8) "JPH-1200" (manufactured by Johoku Chemical Industry Co., Ltd., 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite), CAS number: 13003-12-8) "PEP-36" (manufactured by ADEKA, 3,9-bis(2,6-di-t-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane), CAS number: 80693-00-1)

[0101] <Other antioxidants> "AO-60" (manufactured by ADEKA, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], CAS number: 6683-19-8 "AO-412S" (manufactured by ADEKA, 2,2-bis{[3-(dodecylthio)-1-oxopropoxy]methyl}propane-1,3-diyl bis[3-(dodecylthio)propionate], CAS number: 29598-76-3

[0102] The structures of the antioxidants used are shown below.

[0103]

Chemical

[0104] <Component (C): Curing accelerator> 「TBP-DA」(manufactured by Kitakyo Chemical Industry Co., Ltd., tetrabutylphosphonium decanoate)

[0105] <Component (E): Phenoxy resin> 「YX7200B35」(manufactured by Mitsubishi Chemical Corporation, solution of phenoxy resin having a biphenyl structure and a structure derived from bisphenol TMC, organic solvent: methyl ethyl ketone, non-volatile content: 35%, weight average molecular weight: 30,000, epoxy equivalent: 9,000 g / eq)

[0106] <Component (G): Light stabilizer> 「LA-52」(manufactured by ADEKA, tetrakis(2,2,6,6-tetramethyl-4-piperidinyl) 1,2,3,4-butanetetracarboxylate, CAS No.: 91788-83-9

[0107] <Component (F): Silane coupling agent> 「KBM-403」(manufactured by Shin-Etsu Chemical Co., Ltd., 3-glycidoxypropyltrimethoxysilane) 「KBM-5103」(manufactured by Shin-Etsu Chemical Co., Ltd., 3-acryloxypropyltrimethoxysilane)

[0108] <Organic solvent> 「2-butanone (also called methyl ethyl ketone)」(manufactured by Kanto Chemical Co., Inc.)

[0109] The varnish-like transparent resin compositions of the examples and comparative examples were prepared according to the procedure shown below. In the following description, "parts" of the amount of use of each material means "parts by mass" unless otherwise specified.

[0110] <Example 1> As component (E), 24 parts of a solution of phenoxy resin "YX7200B35" (8.4 parts of phenoxy resin), 9 parts of an epoxy resin "YX7760" having a fluoroalkyl group as component (A), 9 parts of a liquid epoxy resin "ZX1059" as component (D), and 0.26 part of a phosphite antioxidant "JPH-3800" as component (B) were mixed, and the resulting mixture was heated to dissolve component (A) and component (B). Thereto, 0.40 part of a curing accelerator "TBP-DA" was mixed as component (C) to prepare a varnish-like transparent resin composition.

[0111] <Example 2> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that 9 parts of component (A) "EHPE3150" was used instead of 9 parts of component (A) "YX7760".

[0112] <Example 3> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that 18 parts of component (A) "EP-4088S" was used instead of 9 parts of component (A) "YX7760" and component (D) "ZX1059" was not used.

[0113] <Example 4> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that the amount of component (B) "JPH-3800" used was changed from 0.26 part to 1.4 parts.

[0114] <Example 5> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that 0.26 part of component (B) "JPH-1200" was used instead of 0.26 part of component (B) "JPH-3800".

[0115] <Example 6> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that 0.26 part of component (B) "PEP-36" was used instead of 0.26 part of component (B) "JPH-3800".

[0116] <Example 7> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that component (E) "YX7200B35" was not used, the amount of component (B) "JPH-3800" was changed from 0.26 parts to 0.18 parts, and 4.0 parts of the organic solvent "2-butanone" was used.

[0117] <Example 8> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that 0.26 parts of the light stabilizer "LA-52" was further added as component (G).

[0118] <Example 9> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that 0.26 parts of the silane coupling agent "KBM-403" was further added as component (F).

[0119] <Example 10> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that 0.26 parts of the silane coupling agent "KBM-5103" was further added as component (F).

[0120] <Example 11> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that component (D) "ZX1059" was not used and 9 parts of "EP-4088S" was further added as component (A).

[0121] <Comparative Example 1> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that component (A) "YX7760" was not used and the amount of component (D) "ZX1059" was changed from 9 parts to 18 parts.

[0122] <Comparative Example 2> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that component (B) "JPH-3800" was not used.

[0123] <Comparative Example 3> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that 0.26 part of another antioxidant "AO-60" was used instead of 0.26 part of component (B) "JPH-3800".

[0124] <Comparative Example 4> A varnish-like transparent resin composition was prepared in the same manner as in Example 1, except that 0.26 part of another antioxidant "AO-412S" was used instead of 0.26 part of component (B) "JPH-3800".

[0125] <Preparation of Evaluation Samples> The varnish-like transparent resin composition prepared in the example or comparative example was applied onto a PET film ("Lumirror Film 188μm" manufactured by AS ONE Corporation) with a die coater so that the thickness of the dried transparent resin composition layer became 60μm, and dried at 100°C for 7 minutes to form a transparent resin composition layer, thereby obtaining a resin sheet having a laminated structure of "PET film / transparent resin composition layer" (hereinafter referred to as resin laminated sheet). The obtained laminate was heated at 150°C for 60 minutes to thermoset the transparent resin composition layer, thereby obtaining a sheet having a laminated structure of "PET film / resin cured product layer" (hereinafter referred to as resin cured product laminated sheet).

[0126] <Evaluation of Total Light Transmittance> Portions where the thickness of the transparent resin composition layer of the resin laminated sheet obtained in "Preparation of Evaluation Samples" was uniform, and portions where the thickness of the cured product layer of the resin cured product laminated sheet was uniform were each cut into a 3 cm square, and using a fiber-type spectrophotometer ("MCPD-7700" manufactured by Otsuka Electronics Co., Ltd.) equipped with a φ60 mm integrating sphere, the distance between the integrating sphere and the sample was set to 30 mm. In these measurements, the PET film used in the preparation was used as a reference, and the average value of the total light transmittance of the transparent resin composition layer and the cured product layer at wavelengths of 380 to 780 nm was calculated as an index of transparency. The results are shown in Table 1 below. Since the average values of the total light transmittance of the transparent resin composition layer and the cured product layer were the same, only one value is shown in Table 1 below.

[0127] <Measurement of Haze and Evaluation of Transparency> Haze (%) was measured in accordance with JIS K 7136. Specifically, a 3 cm square portion with a uniform thickness of the transparent resin composition layer of the resin laminate sheet obtained in "Preparation of Samples for Evaluation" and a 3 cm square portion with a uniform thickness of the cured product layer of the cured resin laminate sheet were each cut out, and using a haze meter HZ-V3 (halogen lamp) manufactured by Suga Test Instruments Co., Ltd., with air as the reference, the haze (%) was measured under D65 light. The results are shown in Table 1 below. Since the average values of the haze of the transparent resin composition layer and the cured product layer were the same, only one value is shown in Table 1 below.

[0128] <Measurement of b* and Evaluation of Yellowing Resistance> The cured resin laminate sheet obtained in "Preparation of Samples for Evaluation" was left standing in an oven at 180 °C for 2 hours. Then, a 3 cm square portion with a uniform thickness of the cured product layer was cut out, and using a fiber optic spectrophotometer (manufactured by Otsuka Electronics Co., Ltd., "MCPD-7700") equipped with a φ60 mm integrating sphere, with the distance between the integrating sphere and the sample set at 30 mm, air as the reference, a color calculation was performed at a viewing angle of 2 degrees and a light source of D65, the b* in the L*a*b* color system was calculated, and the yellowing resistance was evaluated according to the following criteria. The results are shown in Table 1 below. (Evaluation Criteria for Yellowing Resistance) Good (○): b* is less than 0.8 Fair (△): b* is 0.8 or more and less than 1.2 Poor (×): b* is 1.2 or more

[0129] <Evaluation of Warpage Suppression> A portion with a uniform thickness of the transparent resin composition layer of the uncured resin sheet obtained in "Preparation of Samples for Evaluation" was cut into an 8 cm square, and two adjacent sides out of the four sides were taped to a flat substrate and heated in an oven at 150 °C for 60 minutes to thermally cure the transparent resin composition layer, obtaining a laminate having a laminated structure of "PET film / cured product layer". After taking out the laminate from the oven and allowing it to cool, the height at which the corner not in contact with the tape warped up (hereinafter referred to as "warpage height") was measured, and the warpage suppression was evaluated according to the following criteria. The results are shown in Table 1 below. (Evaluation Criteria for Warpage Suppression) Good (○): Warpage height is less than 20 mm Fair (△): Warpage height is 20 mm or more and less than 30 mm Poor (×): Warpage height is 30 mm or more

[0130]

Table 1

[0131] As shown by the results in Table 1, in Examples 1 to 11, a cured product excellent in yellowing resistance could be formed as compared with Comparative Example 1 in which Component (A) was not used. Further, in Examples 1 to 11, as compared with Comparative Examples 2 to 4 in which Component (B) was not used, a cured product excellent in warpage suppression while maintaining excellent yellowing resistance could be formed.

Industrial Applicability

[0132] Since the transparent resin composition of the present invention can form a cured product excellent in warpage suppression and yellowing resistance, it is useful, for example, as a sealing material or an adhesive material for the transparent part of electronic devices such as LED devices and transparent FPCs.

Claims

1. The following components (A) to (C): (A) An epoxy resin having a fluoroalkyl group and / or an alicyclic structure, (B) A phosphite antioxidant, and (C) A curing accelerator A transparent resin composition containing the same, with respect to the non-volatile content of the transparent resin composition, the content of component (A) is 20 to 94% by mass, the content of component (B) is 0.1 to 10% by mass, and the content of component (C) is 0.1 to 5% by mass, further containing, as component (D), a liquid epoxy resin having neither a fluoroalkyl group nor an alicyclic structure, and A transparent resin composition in which component (B) has a bisphenol structure or a hydrogenated bisphenol structure.

2. The transparent resin composition according to claim 1, wherein the content of component (A) is 20 to 89% by mass with respect to the non-volatile content of the transparent resin composition.

3. The transparent resin composition according to claim 1, wherein the content of component (A) is 20 to 84% by mass with respect to the non-volatile content of the transparent resin composition.

4. The transparent resin composition according to any one of claims 1 to 3, wherein the content of component (B) is 0.3 to 5% by mass with respect to the non-volatile content of the transparent resin composition.

5. The transparent resin composition according to any one of claims 1 to 3, wherein the content of component (B) is 1 to 3% by mass with respect to the non-volatile content of the transparent resin composition.

6. The transparent resin composition according to any one of claims 1 to 5, wherein component (C) is a phosphorus-based curing accelerator.

7. The transparent resin composition according to claim 6, wherein the phosphorus-based curing accelerator is a phosphonium salt.

8. The transparent resin composition according to any one of claims 1 to 7, wherein the content of component (C) is 0.3 to 4% by mass with respect to the non-volatile content of the transparent resin composition.

9. The transparent resin composition according to any one of claims 1 to 7, wherein the content of component (C) is 0.5 to 3% by mass with respect to the non-volatile content of the transparent resin composition.

10. The transparent resin composition according to any one of claims 1 to 9, further containing a phenoxy resin as component (E).

11. The transparent resin composition according to any one of claims 1 to 10, further containing a silane coupling agent selected from the group consisting of a (meth)acryloyl group-containing silane coupling agent, an epoxy group-containing silane coupling agent, and a vinyl group-containing silane coupling agent as component (F).

12. The transparent resin composition according to any one of claims 1 to 11, further comprising a light stabilizer as component (G).

13. The transparent resin composition according to any one of claims 1 to 12, wherein the average value of the total light transmittance of a transparent resin composition layer having a thickness of 60 μm formed from the transparent resin composition is 80% or more at a wavelength of 380 to 780 nm.

14. The transparent resin composition according to any one of claims 1 to 13, wherein the haze of a transparent resin composition layer having a thickness of 60 μm formed from the transparent resin composition is 5% or less.

15. A resin sheet having a laminated structure including a support and a transparent resin composition layer formed from the transparent resin composition according to any one of claims 1 to 14.

16. The resin sheet according to claim 15, wherein the average value of the total light transmittance of the transparent resin composition layer is 80% or more at a wavelength of 380 to 780 nm.

17. The resin sheet according to claim 15 or 16, wherein the haze of the transparent resin composition layer is 5% or less.

18. An electronic device including a cured product layer formed from the transparent resin composition according to any one of claims 1 to 14.

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