JP4910871B2 - Epoxy resin composition and transparent composite sheet - Google Patents

Description

  The present invention relates to an epoxy resin composition and a transparent composite sheet.

In general, glass plates are widely used as display substrates for liquid crystal display elements and organic EL elements, color filter substrates, and solar cell substrates. However, in recent years, plastic materials have been investigated as an alternative to glass plates because they are easily broken, cannot be bent, have large specific gravity, and are not suitable for weight reduction.

  Examples of the resin used for the plastic substrate for the display element include a composition comprising an alicyclic epoxy resin, alcohol and a curing catalyst (see, for example, Patent Document 1), an alicyclic epoxy resin, and an acid anhydride partially esterified with alcohol. Resin composition comprising a curing agent and a curing catalyst (for example, Patent Document 2), an alicyclic epoxy resin, an acid anhydride curing agent having a carboxylic acid, a resin composition comprising a curing catalyst (for example, Patent Document 3), etc. It is shown. However, the linear expansion coefficient of a plastic substrate made of these resin compositions is considerably larger than that of a thin film material such as Si laminated thereon. For this reason, such mismatch of linear expansion coefficients causes thermal stress, distortion, cracks and peeling of the formed layer, and causes the plastic substrate on which the layer is formed to bend. (For example, Non-Patent Document 1)

  Therefore, in recent years, a transparent composite optical sheet comprising an alicyclic epoxy resin having an ester group, a bisphenol A type epoxy resin, an acid anhydride-based curing agent, and a catalyst and glass cloth as a plastic substrate for a display element (for example, Patent Documents) 4), an alicyclic epoxy resin having an ester group and an epoxy resin having a dicyclopentadiene skeleton, a transparent composite optical sheet (for example, Patent Document 5) comprising an acid anhydride curing agent and glass cloth, a bisphenol A type epoxy resin, It has been proposed to use a transparent composite sheet (for example, Patent Document 6) composed of a bisphenol A novolac type epoxy resin, an acid anhydride curing agent, and glass cloth.

In the transparent composite sheet which consists of these resin compositions and glass cloth, a linear expansion coefficient can be reduced significantly compared with the plastic substrate which consists of the resin composition described in the said patent documents 1-3. However, when these transparent composite sheets are used as a plastic substrate for a display element, the heat resistance of the resin is insufficient, the optical anisotropy is large, the display performance is lowered, and the flatness is low, so the display quality is lowered. Problems occur.
JP-A-6-337408 JP 2001-59015 A JP 2001-59014 A JP 2004-51960 A JP 2005-146258 A JP 2004-233851 A Monthly display January 2000 issue p35

  An object of the present invention is to provide a transparent composite sheet having a low linear expansion coefficient, excellent transparency and heat resistance, and low optical anisotropy, and to provide an epoxy resin composition for the transparent composite sheet. .

  As a result of intensive studies to achieve the above object, the present inventors have obtained the following knowledge. That is, an alicyclic epoxy compound obtained by adding hydrogen to the benzene nucleus of a bisphenol having a specific molecular structure, dehydrating the resulting dihydroxybicyclohexyl compound, and further epoxidizing the obtained cyclic diolefin compound The present inventors have found that a transparent composite using a material has a low optical anisotropy, and optical properties are extremely superior to those of conventional transparent composites.

（２）（１）記載の脂環式エポキシ化合物と硬化剤とを含むエポキシ樹脂組成物。
（３）前記硬化剤がカチオン系硬化触媒を含むものである（２）記載のエポキシ樹脂組成物。
（４）前記エポキシ樹脂組成物はさらにカチオン重合可能な化合物を含有する（２）又は（３）記載のエポキシ樹脂組成物。
（５）前記カチオン重合可能な成分が、エポキシ基を有する化合物、オキセタニル基を有する化合物、及びビニルエーテル基を有する化合物より選ばれた１種または２種以上の化合物である（４）記載のエポキシ樹脂組成物。
（６）（２）〜（５）いずれか記載のエポキシ樹脂組成物と、ガラスフィラーとを含有してなる複合組成物を硬化させて得られる透明複合シート。
（７）前記ガラスフィラーの含有量が透明複合シートに対し１〜９０重量％である（６）記載の透明複合シート。
（８）前記ガラスフィラーがガラス繊維布である（６）又は（７）記載の透明複合シート。
（９）波長４００ｎｍにおける光線透過率が８０％以上である（６）〜（８）いずれか記載の透明複合シート
（１０）３０℃〜２５０℃における平均線膨張係数が２０ｐｐｍ以下である（６）〜（９）いずれか記載の透明複合シート。
（１１）（６）〜（１０）いずれか記載の透明複合シートから構成される表示素子用基板。 That is, the present invention is as follows.
(1) An alicyclic epoxy compound represented by the following chemical formula (1).

(2) An epoxy resin composition comprising the alicyclic epoxy compound according to (1) and a curing agent.
(3) The epoxy resin composition according to (2), wherein the curing agent contains a cationic curing catalyst.
(4) The epoxy resin composition according to (2) or (3), wherein the epoxy resin composition further contains a compound capable of cationic polymerization.
(5) The epoxy resin according to (4), wherein the cationically polymerizable component is one or more compounds selected from a compound having an epoxy group, a compound having an oxetanyl group, and a compound having a vinyl ether group. Composition.
(6) A transparent composite sheet obtained by curing a composite composition comprising the epoxy resin composition according to any one of (2) to (5) and a glass filler.
(7) The transparent composite sheet according to (6), wherein the content of the glass filler is 1 to 90% by weight with respect to the transparent composite sheet.
(8) The transparent composite sheet according to (6) or (7), wherein the glass filler is a glass fiber cloth.
(9) The light transmittance at a wavelength of 400 nm is 80% or more. (6) The transparent composite sheet according to any one of (8) (10) The average linear expansion coefficient at 30 ° C to 250 ° C is 20 ppm or less (6) -(9) The transparent composite sheet in any one.
(11) A display element substrate comprising the transparent composite sheet according to any one of (6) to (10).

  By the epoxy resin composition of the present invention, a transparent composite sheet having a low coefficient of linear expansion, excellent transparency and heat resistance, particularly low optical anisotropy and high flatness can be obtained. This transparent composite sheet is suitably used for a liquid crystal display element substrate, an organic EL display element substrate, a color filter substrate, a touch panel substrate, an electronic paper substrate, an optical sheet such as a solar cell substrate, and a transparent plate.

The present invention is an epoxy resin composition comprising an alicyclic epoxy compound having a skeleton obtained by hydrogenating fluorene-type bisphenol represented by the following chemical formula (1) and a curing agent, the epoxy resin composition, and a glass filler Is a transparent composite sheet obtained by curing a composite composition comprising

  The epoxy resin composition of the present invention may contain a component capable of cationic polymerization in addition to the alicyclic epoxy resin represented by the chemical formula (1). The component capable of cationic polymerization is preferably a compound having an epoxy group, a compound having an oxetanyl group, or a compound having a vinyl ether group, and may be used alone or in combination.

  As the compound having these epoxy groups, it is sufficient that at least one epoxy group is contained in the molecule, and various epoxy resins can be used. For example, glycidyl type epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, naphthalene type epoxy resins or hydrogenated products thereof, epoxy resins having a dicyclopentadiene skeleton, triglycidyl isocyanurate. Examples include epoxy resins having a skeleton, epoxy resins having a fluorene skeleton, hydrogenated products thereof, and epoxy resins having a polysiloxane structure. Examples of alicyclic epoxy resins include 3,4-epoxycyclohexylmethyl 3 ′ and 4 ′. -Epoxycyclohexanecarboxylate, 1,2,8,9-diepoxy limonene, epsilon-caprolactone oligomer at both ends of 3,4-epoxycyclohexyl methanol and 3,4-epoxy cyclohexane carbo Which acid is ester bonded, hydrogenated biphenyl skeleton, and cycloaliphatic epoxy resins having hydrogenated bisphenol A skeleton.

The compound having an oxetanyl group is not particularly limited, and examples thereof include 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene (Aron oxetane OXT-121 (XDO)), di [2- (3-Oxetanyl) butyl] ether (Aron oxetane OXT-221 (DOX)), 1,4-bis [(3-ethyloxetane-3-yl) methoxy] benzene (HQOX), 1,3-bis [(3-Ethyloxetane-3-yl) methoxy] benzene (RSOX), 1,2-bis [(3-ethyloxetane-3-yl) methoxy] benzene (CTOX), 4,4′-bis [(3 -Ethyloxetane-3-yl) methoxy] biphenyl (4,4'-BPOX), 2,2'-bis [(3-ethyl-3-oxetanyl) methoxy ] Biphenyl (2,2′-BPOX), 3,3 ′, 5,5′-tetramethyl [4,4′-bis (3-ethyloxetane-3-yl) methoxy] biphenyl (TM-BPOX), 2 , 7-bis [(3-ethyloxetane-3-yl) methoxy] naphthalene (2,7-NpDOX), 1,6-bis [(3-ethyloxetane-3-yl) methoxy] -2,2,3 , 3,4,4,5,5-octafluorohexane (OFH-DOX), 3 (4), 8 (9) -bis [(1-ethyl-3-oxetanyl) methoxymethyl] -tricyclo [5.2 1.0 ^2.6 ] decane, 1,2-bis [2-{(1-ethyl-3-oxetanyl) methoxy} ethylthio] ethane, 4,4′-bis [(1-ethyl-3-oxetanyl) methyl] Thiodibenzene thioether, 2, 3 Bis [(3-ethyloxetane-3-yl) methoxymethyl] norbornane (NDMOX), 2-ethyl-2-[(3-ethyloxetane-3-yl) methoxymethyl] -1,3-O-bis [( 1-ethyl-3-oxetanyl) methyl] -propane-1,3-diol (TMPTOX), 2,2-dimethyl-1,3-O-bis [(3-ethyloxetane-3-yl) methyl] -propane -1,3-diol (NPGOX), 2-butyl-2-ethyl-1,3-O-bis [(3-ethyloxetane-3-yl) methyl] -propane-1,3-diol, 1,4 -O-bis [(3-ethyloxetane-3-yl) methyl] -butane-1,4-diol, 2,4,6-O-tris [(3-ethyloxetane-3-yl) methyl] cyanuric acid ,Screw Enol A and 3-ethyl-3-chloromethyloxetane (abbreviated as OXC) etherified product (BisAOX), bisphenol F and OXC etherified product (BisFOX), phenol novolac and OXC etherified product (PNOX), cresol novolac and OXC Etherified product (CNOX), oxetanylsilsesquioxane (OX-SQ), silicon alkoxide of 3-ethyl-3-hydroxymethyloxetane (OX-SC) 3-ethyl-3- (2-ethylhexyloxymethyl) ) Oxetane (Aron Oxetane OXT-212 (EHOX)), 3-ethyl-3- (dodecyloxymethyl) oxetane (OXR-12), 3-ethyl-3- (octadecyloxymethyl) oxetane (OXR-18) 3-ethyl-3- (phenoxymethi And oxetane (Aron oxetane OXT-211 (POX)), 3-ethyl-3-hydroxymethyloxetane (OXA), 3- (cyclohexyloxy) methyl-3-ethyloxetane (CHOX) and the like. Here, the above parentheses are product names or abbreviations of Toagosei Co., Ltd.

The compound having a vinyl ether group is not particularly limited, but 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol vinyl ether, triethylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, cyclohexanedimethanol monovinyl ether, Examples thereof include tricyclodecane vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, pentaerythritol type tetravinyl ether, and the like.

  The weight ratio of the alicyclic epoxy resin represented by the chemical formula (1) and the component capable of cationic polymerization is preferably 100: 0 to 1:99. More preferably, it is 100: 0-10: 90, More preferably, it is 100: 0-15: 85.

  The curing agent of the epoxy resin composition of the present invention is not particularly limited, but a curing agent such as an acid anhydride or an aliphatic amine, or a curing agent such as a cationic curing catalyst or an anionic curing catalyst can be used.

  When the transparent composite sheet obtained by using the epoxy resin composition of the present invention is applied to a substrate for a display element, in order to realize low optical anisotropy of the substrate, stress generated at the interface between the glass filler and the resin is used. In order to make it as small as possible, a resin that can be cured using a cationic curing catalyst is preferred. This is because if the alicyclic epoxy resin is cured using a cationic curing catalyst, the resin material can be cured at a low temperature. If it can be cured at a low temperature, the interface stress between the glass filler and the resin can be reduced, and if the generated stress is reduced, the optical anisotropy of the composite substrate can be reduced.

  Moreover, when the resin composition is cured using the cationic curing catalyst, the heat resistance (for example, glass transition temperature) of the cured product is higher than that of a cured product cured using another curing agent (for example, an acid anhydride). Because it becomes higher. The reason why the heat resistance of the cured product using the cationic curing catalyst is higher than that using the other catalyst is that the crosslinking density of the cured product obtained by curing the resin composition using the cationic curing catalyst is: This is considered to be because it becomes higher than the crosslink density of a cured product cured using another curing agent (for example, an acid anhydride).

  Examples of the cationic curing catalyst include those that release a substance that initiates cationic polymerization by heating, such as an onium salt cationic curing catalyst or an aluminum chelate cationic curing catalyst), and substances that initiate cationic polymerization by active energy rays. (For example, an onium salt-based cationic curing catalyst). Among these, a thermal cationic curing catalyst is preferable. Thereby, the hardened | cured material which is more excellent in heat resistance can be obtained.

Examples of the thermal cationic curing catalyst include aromatic sulfonium salts, aromatic iodonium salts, ammonium salts, aluminum chelates, and boron trifluoride amine complexes. Specifically, examples of aromatic sulfonium salts include hexafluoroantimonate salts such as SI-60L, SI-80L, SI-100L manufactured by Sanshin Chemical Industries, and SP-66 and SP-77 manufactured by Asahi Denka Kogyo. Examples of the aluminum chelate include ethyl acetoacetate aluminum diisopropylate and aluminum tris (ethyl acetoacetate). Examples of the boron trifluoride amine complex include boron trifluoride monoethylamine complex, boron trifluoride imidazole complex, and trifluoride. Examples thereof include boron bromide piperidine complexes.
Examples of the photocationic curing catalyst include SP170 manufactured by Asahi Denka Kogyo.

  The content of the cationic catalyst is not particularly limited, but is preferably 0.1 to 5 parts by weight, particularly preferably 0.5 to 3 parts by weight with respect to 100 parts by weight of the epoxy resin represented by the chemical formula (1). . When the content is within this range, the curability does not decrease and the cured product has high transparency.

In the case of photocuring, a sensitizer, an acid proliferating agent and the like can be used together to accelerate the curing reaction as necessary.

In the present invention, a transparent composite sheet is obtained by curing a composite composition comprising the epoxy resin composition and a glass filler.
In the transparent composite sheet of the present invention, when the diameter of the glass filler to be used is 100 nm or less, light scattering at the interface is small, but when it exceeds 100 nm, the refractive index between the glass filler and the resin is increased to improve transparency. It is necessary to control and improve transparency

  The refractive index of the glass filler used in the present invention is not particularly limited as long as the diameter is 100 nm or less because scattering at the interface between the glass filler and the matrix resin is small. When the diameter exceeds 100 nm, 1.4 to 1.6 is preferable to suppress scattering, and 1.5 to 1.55 is particularly preferable. This is because it is particularly preferable that the refractive index is in the above range since a transparent resin that is a cured product of the epoxy resin composition close to the Abbe number of the glass filler can be selected. Further, the closer the Abbe number of the transparent resin and the Abbe number of the glass filler are, the higher the refractive index becomes in a wide wavelength region, and a high light transmittance can be obtained in a wide range.

  In the transparent composite sheet of the present invention, the difference between the refractive index after curing of the epoxy resin composition and the refractive index of the glass filler is preferably 0.01 or less, and more preferably 0.005 or less. When the difference in refractive index exceeds the upper limit, the transparency of the obtained transparent composite sheet tends to be inferior. In order to control the difference in refractive index between the glass filler and the resin, the above-described cationic polymerizable component can be appropriately added in addition to the alicyclic epoxy resin which is the main component of the epoxy resin composition.

  Examples of the glass filler used in the present invention include fiber cloths such as cloth and non-woven cloth. Among them, glass cloth and non-woven glass cloth are preferable because the effect of reducing the linear expansion coefficient is high, and glass cloth is more preferable.

  The types of glass include E glass, C glass, A glass, S glass, T glass, D glass, NE glass, quartz, low dielectric constant glass, and high dielectric constant glass, among which ionic impurities such as alkali metals E glass, S glass, and T glass NE glass, which are easy to obtain with little, are preferable.

  It is preferable that content of a glass filler is 1 to 90 weight% with respect to a transparent composite sheet, More preferably, it is 10 to 80 weight%, More preferably, it is 30 to 70 weight%. If the content of the glass filler is within this range, molding is easy, and the effect of reducing linear expansion by compounding is recognized. Moreover, if there is much glass filler amount, the uniformity of the resin amount per unit volume will improve, and the uniformity of stress will improve. When the uniformity is improved, the waviness of the transparent composite substrate is reduced.

  In the present invention, the composite composition, if necessary, is an oligomer or monomer of a thermoplastic resin or a thermosetting resin, as long as it does not impair the properties such as transparency, solvent resistance, low heat resistance, optical properties, and flatness, or A coupling agent or the like may be used in combination. When these oligomers and monomers are used, it is necessary to adjust the composition ratio so that the overall refractive index matches the refractive index of the glass filler. In addition, the composite composition may contain a small amount of an antioxidant, an ultraviolet absorber, a dye / pigment, and other inorganic fillers as long as the properties such as transparency, solvent resistance, and heat resistance are not impaired. May be.

  The production method of the transparent composite sheet of the present invention is not limited, for example, a method in which an uncured epoxy resin composition and a glass filler are directly mixed, cast into a desired one, and then cross-linked into a sheet, uncured The resin composition is dissolved in a solvent and the glass filler is dispersed and cast, and then crosslinked to form a sheet. An uncured epoxy resin composition or a varnish obtained by dissolving an epoxy resin composition in a solvent is used as a glass cloth or Examples include a method of impregnating a glass nonwoven fabric and then crosslinking to form a sheet.

  When the transparent composite sheet of the present invention is used for optical applications such as a liquid crystal display element plastic substrate, a color filter substrate, an organic EL display element plastic substrate, an electronic paper substrate, a solar cell substrate, and a touch panel, the thickness is preferably Is 40 to 200 μm, more preferably 50 to 100 μm.

  When this transparent composite sheet is used as an optical application, the average linear expansion coefficient at 30 ° C. to 150 ° C. is preferably 40 ppm or less, more preferably 20 ppm or less, most preferably 10 ppm or less, and the glass transition temperature is Preferably it is 200 degreeC or more, More preferably, it is 250 degreeC or more.

  When the transparent composite sheet of the present invention is used as a display plastic substrate, the total light transmittance at a wavelength of 400 nm is preferably 80% or more, more preferably 85% or more, and further preferably 88% or more. If the total light transmittance at a wavelength of 400 nm is less than the lower limit, the display performance may not be sufficient.

When the transparent composite sheet of the present invention is used as a plastic substrate for a display element, a resin coat layer may be provided on both sides of the substrate in order to improve smoothness. The resin used for the coat layer preferably has excellent heat resistance, transparency, and chemical resistance. The thickness of the coat layer is preferably 0.1 μm to 30 μm, more preferably 0.5 to 30 μm.

  EXAMPLES Hereinafter, although the content of this invention is demonstrated in detail by an Example, this invention is not limited to the following examples, unless the summary is exceeded.

    The alicyclic epoxy resin represented by the chemical formula (1) is obtained by dehydrating alcohol having a skeleton obtained by hydrogenating a raw material fluorene-type bisphenol according to known information (for example, JP-A No. 2003-13001), followed by peracetic acid. It was synthesized by epoxidation. The synthesis method is described below. Further, the synthesized compound was identified by measuring GC-MS (manufactured by Agilent Technologies) by an electron impact ionization method.

(Synthesis Example 1)
46.83 g (125 mmol) of alcohol having a skeleton in which a fluorene-type bisphenol is hydrogenated in a four-necked 500 mL flask equipped with a stirrer, equipped with a thermometer, a nitrogen introduction tube and a reflux tube, and triphenyl phosphite 85. 33 g (275 mmol), 35.52 g (275 mmol) of quinoline and 200 ml of N-methylpyrrolidone were charged and heated at 200 ° C. for 7 hours in a nitrogen atmosphere. After cooling to room temperature, the reaction solution was poured into a 2 L separatory funnel, 300 ml of ethyl acetate, 300 ml of pure water, and 200 ml of 1 mol / L sulfuric acid were added, and the organic layer (ethyl acetate layer) was recovered. The aqueous layer was extracted twice with 200 ml of ethyl acetate, and all the organic layers (ethyl acetate layer) were combined and washed twice with 500 ml of 1 mol / L sulfuric acid and twice with 500 ml of 1 mol / L sodium carbonate aqueous solution. After potassium carbonate was added and dried, ethyl acetate was removed with an evaporator. Purification by silica gel column chromatography (developing solvent: hexane) and removal of hexane with an evaporator gave 32.16 g of a cyclic olefin compound dehydrated from an alcohol having a skeleton in which fluorene-type bisphenol was hydrogenated (yield) 76%). Since it has a maximum molecular weight of 338 by GC-MS measurement, it was confirmed that the obtained compound was the target cyclic olefin compound.
Subsequently, the method of the literature (K. Sato, M. Aoki, M. Ogawa, T. Hashimoto, D. Panyella, and R. Noyori; Bull. Chem. Soc. Jpn., 70, 905-915 (1997)). Then, the epoxidation of the cyclic olefin compound was performed. A 300 mL eggplant flask equipped with a nitrogen introduction tube and a reflux tube and containing a stirring bar was charged with 1.30 g (3.54 mmol) of sodium tungstate dihydrate, 0.20 g (1.77 mmol) of aminomethanephosphonic acid, 30% excess. Charge 15.07 g (132.9 mmol) of hydrogen oxide water and 0.83 g (1.77 mmol) of trioctylmethylammonium sulfate, and stir at room temperature for 20 minutes. Subsequently, 30.00 g of the cyclic olefin compound obtained above and 30 ml of toluene were added, and the mixture was stirred at 70 ° C. for 2 hours. The organic layer was collected, and the aqueous layer was extracted twice with 30 ml of toluene. All the organic layers were combined and about 60 ml of toluene was removed with an evaporator. Purification by silica gel chromatography (developing solvent: toluene / ethyl acetate = 10/1), and removal of toluene and ethyl acetate by an evaporator gave 21.67 g of the desired epoxy compound (yield 66%). Since the maximum molecular weight was 370 as measured by GC-MS, it was confirmed that the obtained compound was an epoxy compound represented by the target chemical formula (1).

[Create transparent composite sheet]
Example 1
It was obtained in Synthesis Example 1 with a T glass-based glass cloth (thickness 95 μm, refractive index 1.526, manufactured by Nittobo), 80 parts by weight of hydrogenated biphenyl type alicyclic epoxy resin (manufactured by Daicel Chemical Industries, E-BP). A resin composition in which 20 parts by weight of an alicyclic epoxy compound and 1 part by weight of an aromatic sulfonium-based thermal cation catalyst (SI-100L manufactured by Sanshin Chemical Co., Ltd.) were mixed was impregnated and defoamed. This glass cloth was sandwiched between release-treated glass plates, heated at 80 ° C. for 2 hours, and further heated at 250 ° C. for 2 hours to obtain a 97 μm thick transparent composite sheet.

(Example 2)
It was obtained in Synthesis Example 1 with a T glass-based glass cloth (thickness 95 μm, refractive index 1.526, manufactured by Nittobo Co., Ltd.), 70 parts by weight of a hydrogenated biphenyl type alicyclic epoxy resin (manufactured by Daicel Chemical Industries, E-BP). A resin composition mixed with 30 parts by weight of an alicyclic epoxy compound and 1 part by weight of an aromatic sulfonium-based thermal cation catalyst (SI-100L, manufactured by Sanshin Chemical) was impregnated and defoamed. This glass cloth was sandwiched between release-treated glass plates, heated at 80 ° C. for 2 hours, and further heated at 250 ° C. for 2 hours to obtain a 97 μm thick transparent composite sheet.

Example 3
It was obtained in Synthesis Example 1 with a T glass-based glass cloth (thickness 95 μm, refractive index 1.526, manufactured by Nittobo Co., Ltd.), 60 parts by weight of a hydrogenated biphenyl type alicyclic epoxy resin (manufactured by Daicel Chemical Industries, E-BP). A resin composition in which 40 parts by weight of an alicyclic epoxy compound and 1 part by weight of an aromatic sulfonium-based thermal cation catalyst (SI-100L manufactured by Sanshin Chemical Co., Ltd.) were mixed was impregnated and defoamed. This glass cloth was sandwiched between release-treated glass plates, heated at 80 ° C. for 2 hours, and further heated at 250 ° C. for 2 hours to obtain a 97 μm thick transparent composite sheet.

(Comparative Example 1)
T glass-based glass cloth (thickness 95 μm, refractive index 1.526, manufactured by Nittobo), hydrogenated biphenyl type alicyclic epoxy resin (manufactured by Daicel Chemical Industries, E-BP) 100 parts by weight, aromatic sulfonium-based thermal cation catalyst (SI-100L manufactured by Sanshin Chemical Co., Ltd.) The resin composition mixed with 1 part by weight was impregnated and defoamed. This glass cloth was sandwiched between release-treated glass plates, heated at 80 ° C. for 2 hours, and further heated at 250 ° C. for 2 hours to obtain a 97 μm thick transparent composite sheet.

Table 1 shows the composition of the transparent composite sheets of Examples and Comparative Examples and the evaluation results of the properties.
The evaluation method is as follows.

(A) Average linear expansion coefficient Using a TMA / SS6000 type thermal stress strain measuring device manufactured by SEIKO ELECTRONICS CO., LTD., The temperature is raised at a rate of 5 ° C. per minute in a nitrogen atmosphere, and the load is set to 5 g in a tensile mode. Measurement was performed and an average linear expansion coefficient in a predetermined temperature range was calculated.

(B) Heat resistance Using a DNS210 type dynamic viscoelasticity measuring device manufactured by SEIKO Electronics Co., Ltd., the maximum value of tan δ at 1 Hz was defined as the glass transition temperature (Tg).

(C) Light transmittance The total light transmittance at 400 nm was measured with a spectrophotometer U3200 (manufactured by Shimadzu Corporation).

(D) Optical anisotropy After making it into a crossed Nicol state using an optical microscope, evaluation was performed at a position where the light transmittance was strongest while rotating the transparent substrate on the stage. Each code is as follows.
A: Best (almost no light transmission)
○: Good (light transmission is slightly observed)

  The transparent composite sheet of the present invention includes, for example, a transparent plate, an optical lens, a plastic substrate for a liquid crystal display element, a substrate for a color filter, a plastic substrate for an organic EL display element, a substrate for electronic paper, a solar cell substrate, a touch panel, a light guide plate, optical It can utilize suitably for an element, an optical waveguide, LED sealing material, etc.

Claims (11)

An alicyclic epoxy compound represented by the following chemical formula (1).

An epoxy resin composition comprising the alicyclic epoxy compound according to claim 1 and a curing agent. The epoxy resin composition according to claim 2, wherein the curing agent contains a cationic curing catalyst. The epoxy resin composition according to claim 2 or 3, wherein the epoxy resin composition further contains a compound capable of cationic polymerization. The epoxy resin composition according to claim 4, wherein the cationically polymerizable component is one or more compounds selected from a compound having an epoxy group, a compound having an oxetanyl group, and a compound having a vinyl ether group. A transparent composite sheet obtained by curing a composite composition comprising the epoxy resin composition according to claim 2 and a glass filler. The transparent composite sheet according to claim 6, wherein the content of the glass filler is 1 to 90% by weight with respect to the transparent composite sheet. The transparent composite sheet according to claim 6 or 7, wherein the glass filler is a glass fiber cloth. The transparent composite sheet according to any one of claims 6 to 8, wherein the light transmittance at a wavelength of 400 nm is 80% or more. The transparent composite sheet according to any one of claims 6 to 9, wherein an average linear expansion coefficient at 30 ° C to 250 ° C is 20 ppm or less. A display element substrate comprising the transparent composite sheet according to claim 6.