JP5196705B2 - Optical sheet - Google Patents

Description

  The present invention relates to an optical sheet having a small coefficient of linear expansion, excellent surface smoothness, transparency, heat resistance and solvent resistance, and capable of replacing glass. This optical sheet is preferable for a liquid crystal display substrate, an organic EL display element substrate, a color filter substrate, a touch panel substrate, a solar cell substrate, and the like.

  In general, glass plates are widely used for active matrix type liquid crystal display elements, display element substrates for organic EL display elements, color filter substrates, solar cell substrates, and the like. However, in recent years, various plastic materials have been studied as alternatives because glass plates are easily broken, cannot be bent, have a large specific gravity, and are not suitable for weight reduction.

For example, Patent Document 1 discloses that a member obtained by curing an active energy ray with respect to a resin composition made of an amorphous thermoplastic resin and bis (meth) acrylate capable of curing an active energy ray is a liquid crystal substrate. For example, it can be used instead of a glass substrate. Patent Document 2 describes a liquid crystal display element using a transparent substrate obtained by curing a composition containing a specific bis (meth) acrylate such as an alicyclic structure or aromatic with active energy rays or the like. .
Patent Document 3 and Patent Document 4 describe a transparent resin substrate for a liquid crystal display element comprising a cured product obtained by curing an epoxy resin composition containing an epoxy resin, an acid anhydride curing agent, and a curing catalyst. ing.

  However, all of these conventional plastic materials for glass replacement have a larger coefficient of linear expansion than glass plates, and when used for display element substrates, particularly active matrix display element substrates, warpage and disconnection of aluminum wiring in the manufacturing process. May be difficult to use for these purposes. Thus, there is a demand for a plastic material having a small coefficient of linear expansion while satisfying the transparency, solvent resistance, heat resistance, etc. required for a display element substrate, particularly an active matrix display element substrate.

  In order to reduce the coefficient of linear expansion, various composites of materials in which an inorganic filler such as glass powder or glass cloth is blended with a resin have been performed. For example, Patent Document 5 discloses a resin sheet including an epoxy resin and a glass fiber cloth. However, especially when glass cloth is used, the effect of reducing the linear expansion coefficient is great, but due to differences in the linear expansion coefficient between resin and glass, curing shrinkage of the resin, etc., unevenness derived from glass cloth is formed on the sheet surface after molding. Therefore, an optical sheet that requires surface smoothness has been required to be improved.

JP 10-77321 A JP-A-10-90667 JP-A-6-337408 Japanese Patent Laid-Open No. 7-210740 JP 2004-51960 A

An object of the present invention is to provide an optical sheet that has sufficient smoothness, a small linear expansion coefficient, excellent transparency, heat resistance, and solvent resistance and can be substituted for glass. The optical sheet of the present invention is suitable for applications such as active matrix type liquid crystal display element substrates, organic EL display element substrates, color filter substrates, touch panel substrates, and solar cell substrates.

  The present inventors diligently studied to solve this problem. As a result, the organic coat layer (c) is laminated on the sheet (A) composed of the transparent resin (a) and the glass fiber (b) to reduce the unevenness derived from the glass fiber, and at least one surface unevenness is 150 nm or less. The optical sheet has a low linear expansion coefficient and excellent surface smoothness, such as a liquid crystal display element substrate including an active matrix type, an organic EL display element substrate, a color filter substrate, a touch panel substrate, and a solar cell substrate. It has been found that it can be suitably used for applications, and the present invention has been completed.

  The transparent composite composition of the present invention has sufficient smoothness and has a low coefficient of linear expansion and excellent transparency, heat resistance, solvent resistance, and the like. For example, a plastic substrate for a liquid crystal display element, a substrate for a color filter It can be suitably used for a plastic substrate for an organic EL display element, a solar cell substrate, a touch panel, and the like, and is particularly preferable as an optical sheet for an active matrix type liquid crystal display element substrate or an organic EL element substrate.

Hereinafter, the present invention will be described more specifically.
At least one surface of the optical sheet of the present invention has a surface unevenness of 150 nm or less, preferably 100 nm or less, and most preferably 30 nm or less. In particular, when used for liquid crystal applications, the smoothness of the cell inner surface is preferably 100 nm or less, and when used for STN liquid crystal, it is preferably 30 nm or less. When the surface unevenness is 150 nm or more, the cell gap becomes non-uniform, which may cause display unevenness.
The thickness of the organic coat layer (c) is 1 μm to 30 μm, preferably 2 μm to 15 μm, on one side of the sheet. When the thickness is 1 μm or less, the thickness is less than the unevenness of the sheet, and the organic coating layer (c) is not sufficiently embedded. A thickness of 30 μm or more is not preferable because warpage and cracks after curing occur.

As described above, the sheet (A) prepared from the transparent resin (a) and the glass cloth (b) is likely to have irregularities on the surface due to the difference in curing shrinkage rate and linear expansion coefficient between the glass cloth and the resin. In many cases, since the surface unevenness exceeds 150 nm, it is preferable to fill the surface unevenness by laminating the organic coat layer (c).
The thickness of the organic coat layer (c) is 1 μm to 30 μm, preferably 2 μm to 15 μm, on one side of the sheet. When the thickness is 1 μm or less, the organic coating layer (c) is not sufficiently embedded. In the case of 30 μm or more, it is not preferable because warping and cracking occur after curing.

  The glass transition temperature of the resin used for the organic coat layer (c) is preferably 150 ° C. or higher, more preferably 200 ° C. or higher. When the glass transition temperature of the resin is lower than this, particularly when used in an active matrix type display element substrate, the organic coat layer (c) may be deformed in the TFT element forming step, and the surface unevenness may increase.

Examples of the resin used for the organic coat layer (c) include a resin obtained by crosslinking a reactive monomer such as acrylate or epoxy with active energy rays and / or heat. Among these, since it is excellent in heat resistance, transparency, solvent resistance, and scratch resistance, a crosslinked resin containing a bifunctional or higher functional acrylate as a constituent component, or a cured resin containing a bifunctional or higher functional epoxy resin as a constituent component Is preferred.
Examples of the bifunctional or higher acrylate include epoxy acrylate, urethane acrylate, polyester acrylate, acrylate having an isocyanurate structure, acrylate having a cyclic ether structure, acrylate having an alicyclic structure, and the like. A structural acrylate having a cyclic ether and an acrylate having an alicyclic structure are more preferable because of excellent heat resistance and transparency. Furthermore, as an acrylate having an isocyanurate structure, an acrylate having the following formula (1) and an acrylate having a cyclic ether structure are more preferable because the acrylate having the following formula (2) is more excellent in heat resistance.

The bifunctional or higher epoxy resin is more preferably a curable resin containing one or more selected from triglycidyl isocyanurate and epoxy having an alicyclic structure as a constituent component. Among these, one or more selected from alicyclic epoxy resins represented by the following chemical formulas (3) to (5) are more preferable.

  In general, in order to obtain excellent heat resistance, an acrylate resin or an epoxy resin having a ring having a conjugated double bond such as aromatic is used, but the light transmittance on the short wavelength side (around 400 nm) of visible light. , And tends to give a yellowish color, which is not preferable as an optical film. The above acrylate resins and epoxy resins have a cyclic structure with no conjugated double bonds, so they have excellent heat resistance, little change in light transmittance over the entire visible light range, and almost no coloration, so they are used preferably I can do it.

  In the organic coat layer (c) of the present invention, if necessary, thermoplastic or thermosetting oligomers or polymers may be used in combination as long as the properties such as transparency, solvent resistance, and heat resistance are not impaired. In this case, it is preferable to use an oligomer or polymer having an alicyclic structure or a cardo skeleton for the purpose of reducing water absorption.

  In order to crosslink the acrylate resin or the epoxy resin used for the organic coat layer (c), there are a method of curing with active energy rays, a method of heat polymerization by applying heat, and the like, and these may be used in combination. When an acrylate resin is used, a method of curing with active energy rays is preferable. Further, for the purpose of completing the reaction and improving the adhesion to the sheet, it is preferable to further use a heat treatment at a higher temperature after the step of curing with active energy rays and / or heat polymerization. In particular, when the reaction is not completed, the reaction proceeds during the heating process in the display element manufacturing process, and the surface unevenness may increase. The active energy ray used is preferably ultraviolet rays. Examples of the ultraviolet light source include a metal halide type and a high-pressure mercury lamp lamp. When heat treatment is performed at a high temperature after crosslinking by active energy rays and / or thermal polymerization, it is preferably performed in a nitrogen atmosphere or in a vacuum state in order to suppress coloring due to heating, and a heating temperature of 150 to 300 ° C. for 1 to 24 hours. It is preferable to add the heat treatment step.

In order to crosslink and cure the acrylate resin used for the organic coat layer (c) with active energy rays such as ultraviolet rays, it is preferable to add a photopolymerization initiator that generates radicals in the resin composition. Examples of such photopolymerization initiator include benzophenone, benzoin methyl ether, benzoin propyl ether, diethoxyacetophenone, 1-hydroxy-cyclohexyl-phenyl ketone, 2,6-dimethylbenzoyl diphenylphosphine oxide,
2,4,6-trimethylbenzoyldiphenylphosphine oxide is mentioned. Two or more of these photopolymerization initiators may be used in combination.

The content of the photopolymerization initiator in the composite composition may be an appropriate amount to be cured, and is preferably 0.01 to 5 parts by weight with respect to a total of 100 parts by weight of the bifunctional or higher acrylate,
More preferred is 0.02 to 1 part by weight, and most preferred is 0.1 to 0.5 part by weight. When the amount of the photopolymerization initiator added is too large, the polymerization proceeds rapidly, and problems such as coloring and cracking during curing occur. Moreover, when there is too little, there exists a possibility that a composition cannot fully be hardened.

  The epoxy resin used for the organic coat layer (c) is used after being cured by heating or irradiation with active energy rays in the presence of a curing agent or a polymerization initiator. The curing agent to be used is preferably an acid anhydride curing agent or a cationic catalyst because an excellent transparent cured product can be easily obtained. Acid anhydride curing agents include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyl nadic anhydride, nadic anhydride, glutaric anhydride, methyl Examples include hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl hydrogenated nadic acid anhydride, hydrogenated nadic acid anhydride, etc. Among them, methyl hexahydrophthalic anhydride and methyl hydrogenated nadic acid anhydride are excellent in transparency. Is preferred.

  When using an acid anhydride curing agent, it is preferable to use a curing accelerator in combination. Examples of the curing accelerator include 1,8-diaza-bicyclo (5,4,0) undecene-7, tertiary amines such as triethylenediamine, 2-ethyl-4-methylimidazole and 1-benzyl-2-phenyl. Examples include imidazoles such as imidazole, phosphorus compounds such as triphenylphosphine and tetraphenylphosphonium tetraphenylborate, quaternary ammonium salts, organometallic salts, and derivatives thereof. Among these, phosphorus is excellent because of its excellent transparency. Compounds and imidazoles such as 1-benzyl-2-phenylimidazole are preferred. These curing accelerators may be used alone or in combination of two or more.

The blending ratio of the epoxy resin and the acid anhydride curing agent is set such that the acid anhydride group in the acid anhydride curing agent is 0.5 to 1.5 equivalents with respect to 1 equivalent of the epoxy group in the epoxy resin. It is preferably 0.7 to 1.2 equivalents.
Cationic catalysts include organic acids such as acetic acid, benzoic acid, salicylic acid, paratoluenesulfonic acid, boron trifluoride amine complex, boron trifluoride ammonium salt, aromatic diazonium salt, aromatic sulfonium salt, aromatic iodonium. Examples thereof include a cationic catalyst containing a salt and an aluminum complex. Among these, a cationic catalyst containing an aluminum complex, an aromatic sulfonium salt and an aromatic iodonium salt are preferable.
Depending on the application, it is not always necessary that both sides of the optical sheet are smooth. However, when the organic coat layer (c) is laminated only on one side of the sheet (A), a problem such as insufficient chemical resistance and killing resistance may occur. In that case, the organic coat layer (c) is attached to the sheet ( It is necessary to laminate on both sides of A).

  Examples of the method for applying the organic coat layer (c) onto the sheet (A) include gravure coating, kiss coating, spin coating, bar coating, and dip coating, but the method is not particularly limited. Moreover, you may use a solvent and surfactant for improvement of productivity and a coating external appearance.

  In order to improve the adhesion between the organic coat layer (c) and the sheet (A), it may be treated with a known surface treatment agent such as a silane coupling agent. Examples of the treatment method include a method of treating the coupling agent on the coated surface (direct treatment method) and a method of mixing in an organic coat resin (integral blend method), but any treatment method may be used. Specifically, when an acrylate resin having two or more functional groups is used as the reactive monomer, it is preferably treated with acrylic silane, mercaptosilane, or aminosilane.

  The resin used in the organic coating layer (c) of the present invention may contain a small amount of an antioxidant, an ultraviolet absorber, as long as it does not impair the properties such as transparency, solvent resistance, and heat resistance. You may mix | blend fillers, such as a dye and a pigment and another inorganic filler.

When the optical sheet of the present invention is used as an optical application, that is, a plastic substrate for liquid crystal display elements, a substrate for color filters, a plastic substrate for organic EL display elements, a solar cell substrate, a touch panel, etc., an average line of 30 to 150 ° C. The expansion coefficient is preferably 40 ppm or less. In particular, when used for an active matrix display element substrate, the average linear expansion coefficient is preferably 30 ppm or less, more preferably 20 ppm or less. If the above value is exceeded, problems such as warpage and disconnection of aluminum wiring may occur in the manufacturing process. However, if the linear expansion coefficient is less than the above value, the equipment when using the conventional glass substrate is greatly changed. It is possible to carry out the TFT formation process without any further.

  When the sheet of the present invention is used as a plastic substrate for liquid crystal display elements, a substrate for color filters, a plastic substrate for organic EL display elements, a solar cell substrate, a touch panel, etc., the thickness of the substrate is preferably 50 to 2000 μm, More preferably, it is 50-1000 micrometers. If the thickness of the substrate is within this range, the flatness is excellent, and the weight of the substrate can be reduced as compared with the glass substrate.

  Examples of the transparent resin (a) used in the present invention include thermoplastic resins such as polycarbonate, polyarylate, polysulfone, polyethersulfone, and cycloolefin polymer, and reactive monomers such as acrylate and epoxy as heat and / or active energy rays. And a resin cross-linked with. In the case of thermoplastic resins, there are problems such as retardation during molding and insufficient chemical resistance, but resins obtained by crosslinking reactive monomers such as acrylates and epoxies with heat and / or active energy rays have low retardation and are resistant to resistance. It is preferable because of its excellent chemical properties. In particular, when a reactive monomer having an alicyclic structure is included, since it has excellent heat resistance and light transmittance, it is an active matrix type liquid crystal display element, a display element substrate for an organic EL display element, a color filter substrate, a solar cell. It is preferably used by a substrate for use.

  Further, when the optical sheet of the present invention is used as a plastic substrate for a display substrate, the parallel light transmittance at a wavelength of 550 nm is preferably 80% or more, more preferably 85% or more, and most preferably 88% or more. . When the parallel light transmittance at a wavelength of 550 nm is lower than 80%, the display performance is not sufficient.

In such an optical sheet, a method of matching the refractive indexes of the transparent resin (a) and the glass fiber (b) is preferable in order to make the parallel light transmittance at a wavelength of 550 nm 80% or more. The refractive index difference between the transparent resin (a) and the glass fiber (b) needs to be 0.01 or less in order to obtain excellent transparency, and is more preferably 0.005 or less. If the refractive index difference is greater than 0.01, the resulting composite composition tends to have poor transparency.

  Although the refractive index of the glass fiber (b) mix | blended with the transparent composite composition of this invention is not specifically limited, The range of 1.50-1.57 is easy so that adjustment of the refractive index of resin to combine is easy. It is preferable that it exists in. In particular, when the refractive index of the glass fiber (b) is 1.50 to 1.54, a resin close to the Abbe number of glass can be selected, which is preferable. When the Abbe numbers of the resin and glass are close, the refractive indexes of the two coincide in a wide wavelength region, and a high light transmittance is obtained in a wide wavelength region.

  Examples of the glass include E glass, C glass, A glass, S glass, D glass, NE glass, T glass, quartz, low inductivity glass, and high inductivity glass. E glass, S glass, T glass, and NE glass, which have few impurities and are easily available, are preferred.

  The blending amount of the glass fiber in the sheet (A) is preferably 1 to 90% by weight, more preferably 10 to 80% by weight, and still more preferably 30 to 70% by weight. When the blending amount of the glass fiber is less than this, the effect of reducing the linear expansion due to the composite is not recognized, whereas when it is more than this, the molded appearance tends to be lowered.

There are no restrictions on the method of forming the sheet (A). For example, when a reactive monomer is used as the transparent resin, (1) the reactive monomer and glass cloth are directly mixed and cast into the required mold. Crosslinking method, (2) Dissolving reactive monomer in solvent and dispersing and casting glass cloth, then crosslinking, and (3) impregnating reactive monomer into glass fiber cloth and crosslinking, if necessary To make a sheet.

When the optical sheet of the present invention is used for a liquid crystal display substrate, an organic EL display element substrate, a color filter substrate, or the like, a laminate in which an inorganic oxide is laminated as the gas barrier layer (e) is preferably used. Among these, silicon oxide and SiOx (x = 1.5 to 1.8) are more preferable because of excellent transparency and barrier properties against water vapor and oxygen. When x is larger than 1.8, the transparency of the resulting inorganic layer increases, but the barrier property decreases. On the other hand, when x of SiOx is 1.5 or less, the barrier property is increased, but the silicon oxide is slightly brown and the transparency is deteriorated. The inorganic layer may be formed by a conventional method such as a physical method (vacuum deposition method, reactive deposition method, sputtering method, reactive sputtering method, ion plating method, reactive ion plating method, etc.), chemical method (CVD The surface of the organic coating layer (c) can be formed by coating with the inorganic oxide by a method, a plasma CVD method, a laser CVD method or the like.
If the gas barrier layer (e) is flawed or cracked, the gas barrier property is lowered and the performance is not sufficiently exhibited. Therefore, in order to protect the gas barrier layer, the organic coat layer (c) having excellent killing resistance is preferably laminated on the outside thereof.

  Examples of the method for forming the gas barrier layer (e) include, but are not limited to, sputtering, vacuum deposition, ion plating, chemical vapor deposition, and sol-gel method.

  When the optical sheet of the present invention is used for a liquid crystal display substrate, an organic EL display substrate, a touch panel substrate, a solar cell substrate, or the like, a laminate in which a conductive layer (d) is laminated on the outermost layer is more preferably used. The conductive layer (d) provided on the optical sheet of the present invention may be a conventionally known one. The conductive layer material is indium oxide, indium-tin alloy oxide (ITO), tin oxide, tin oxide with addition of fluorine, zinc oxide, aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, tantalum oxide, oxide Examples thereof include a single layer or a stack of oxides made of at least one of niobium and selenium oxide. Of these, indium oxide, ITO, tin oxide added with fluorine, and zinc oxide are particularly preferable. The thickness of the conductive layer is usually preferably 100 to 3000 mm. If the thickness of the conductive layer is thinner than this, the conductivity is not sufficient, while if it is too thick, the transparency is impaired. From the balance of transparency and conductivity, a conductive layer mainly composed of indium oxide is more preferable, and ITO (mixture of indium oxide and tin oxide) is most preferable. Moreover, when using it for display elements, the unevenness | corrugation of the surface which forms a conductive layer (d) needs to be 150 nm or less. If it exceeds 150 nm, a display defect may occur due to a non-uniform cell gap.

  Examples of the method for forming the conductive layer (d) include, but are not limited to, a sputtering method, a vacuum deposition method, an ion plating method, and a chemical vapor deposition method.

The layer structure of the optical sheet of the present invention is not particularly limited, but examples include (1) organic coating layer (c
) / Gas barrier layer (e) / Organic coat layer (c) / Sheet (A) / Organic coat layer (c) / Gas barrier layer (e) / Organic coat layer (c) / Conductive layer (d), (2) Organic Coat layer (c) / gas barrier layer (e) / organic coat layer (c) / sheet (A) / organic coat layer (c) / conductive layer (d), (3) organic coat layer (c) / gas barrier layer ( e) / organic coating layer (c) / sheet (A)
/ Organic coating layer (c) / gas barrier layer (e) / organic coating layer (c), (4) organic coating layer (
c) / gas barrier layer (e) / organic coating layer (c) / sheet (A) / organic coating layer (c), (5) organic coating layer (c) / gas barrier layer (e) / organic coating layer (c) / Sheet (A), (6)
Organic coating layer (c) / sheet (A) / organic coating layer (c), (7) organic coating layer (c) / sheet (A), etc. In order to protect the gas barrier layer (e) and improve adhesion, it is preferable to provide an organic coat layer (c) in a layer adjacent to the gas barrier layer (e). If the required gas barrier property is low, the gas barrier layer (e) may be omitted, and if a high level of barrier property is required, the gas barrier layer (e) may be formed in multiple layers. The coat layer (c) and the gas barrier layer (e) may be alternately formed.

  The present invention will be described in more detail below by way of examples, but these examples do not limit the scope of the present invention.

Example 1
NE glass-based glass cloth (thickness 100 μm, refractive index 1.510, manufactured by Nittobo) was baked to remove organic substances, and then treated with γ-glycidoxypropyltrimethoxysilane (epoxysilane). To this glass cloth, 40 parts by weight of triglycidyl isocyanurate (TEPIC manufactured by Nissan Chemical Industries), 59 parts by weight of methylhexahydrophthalic anhydride (Ricacid MH-700 manufactured by Shin Nippon Chemical Co., Ltd.), 1-benzyl-2-phenylimidazole (1B2PZ) One part by weight was impregnated with a resin melt-mixed at 100 ° C. and defoamed. This glass cloth impregnated with resin is sandwiched between release-treated glass plates, heated in an oven at 100 ° C. for 2 hours, further at 120 ° C. for 2 hours, at 150 ° C. for 2 hours, and at 175 ° C. for 2 hours. Heat for time, thickness 0.1m
m transparent sheet was obtained.

Isocyanuric acid ethylene oxide modified acrylate (Made by Toagosei Co., Ltd.)
-315) A resin composition for organic coating comprising 100 parts by weight, 1 part by weight of a photopolymerization initiator Irgacure 907 (manufactured by Ciba Specialty Chemical) and 0.5 part by weight of Irgacure 651 (manufactured by Ciba Specialty Chemical) at 80 ° C. After dissolution by heating, it was applied to a thickness of about 5 μm with a bar coater, and cured by irradiation with UV light of about 300 mJ / cm ² . Similarly, the opposite surface of the sheet was coated and irradiated with UV light, and further heated in a vacuum oven at about 200 ° C. for 1 hour to form an organic coating layer.

(Example 2)
A plastic sheet (thickness: about 0.1 mm) prepared in the same manner as in Example 1, 100 parts by weight of isocyanuric acid ethylene oxide-modified acrylate (M-315 manufactured by Toagosei Co., Ltd.), and photopolymerization initiator Irgacure 907 (Ciba) A resin composition for organic coating consisting of 1 part by weight (speciality chemical) and 0.5 part by weight Irgacure 651 (manufactured by Ciba Specialty Chemical) is heated and dissolved at 80 ° C. and then applied to a thickness of about 5 μm with a bar coater. 300 mJ / c
It was cured by irradiating m ² UV light. Furthermore, it heated at about 200 degreeC in the vacuum oven for 1 hour, and formed the organic coating layer.
Subsequently, a silicon oxide film having a thickness of 50 nm was formed on one surface of the optical sheet using a sputtering apparatus. The silicon oxide film uses silicon as a raw material target, the pressure inside the sputtering apparatus is reduced to 10 ⁻³ Pa or less, argon is introduced as a discharge gas at a partial pressure of 0.04 Pa, and oxygen is used as a reaction gas at a partial pressure of 0.04 Pa. Then, reactive sputtering was performed to form a film. Further, an organic coat layer was applied as a protective layer to a thickness of about 5 μm on the silicon oxide film by the same method. Subsequently, a mixed gas of oxygen / argon gas 4% was introduced from the state of the initial vacuum degree of 3 × 10 ⁻⁴ Pa by the DC magnetron method on the surface opposite to the silicon oxide film formed as the transparent conductive layer. Then, sputtering was performed under the condition of 1 × 10 ⁻¹ Pa to obtain a transparent conductive film made of indium tin oxide (ITO) having an In / (In + Sn) atomic ratio of 0.98. As a result of the measurement, the film thickness was 1600 mm and the specific resistance was 4 × 10 ⁻⁴ Ω-cm.

(Example 3)
A NE glass-based glass cloth of 100 μm (Nittobo # 2116 type, refractive index 1.510) was baked to remove organic substances, and then treated with acryloyloxypropyltriethoxysilane (acrylic silane). To this glass cloth, 80 parts by weight of caprolactone-modified hydroxypivalate ester neopentyl glycol diacrylate (Nippon Kayaku Co., Ltd. KAYARAD HX-220, refractive index 1.493 after crosslinking), dicyclopentadienyl diacrylate ( M-203 manufactured by Toagosei Co., Ltd., 3 parts by weight of refractive index after crosslinking 1.527), 17 weights of bis [4- (acryloyloxyethoxy) phenyl] fluorene (prototype TO-2065) manufactured by Toagosei Co., Ltd. And impregnated with a resin (refractive index after cross-linking 1.510) of 0.5 parts by weight of 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184 manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator, and defoamed did. The cloth impregnated with the resin was sandwiched between release-molded glass plates and cross-linked by irradiation with a total of about 2000 mJ / cm ² of UV light from both sides. Further in a vacuum oven at 100 ° C. for 2 hours, further 2
Heat treatment was performed at 50 ° C. for 3 hours to obtain a 0.1 mm transparent sheet.
An organic coat layer, a silicon oxide film, and a transparent conductive layer were formed on this sheet in the same manner as in Example 2.

Example 4
A plastic sheet (thickness of about 0.1 mm) prepared in the same manner as in Example 1 is represented by chemical formula (3)
A resin composition for organic coating comprising 100 parts by weight of an alicyclic epoxy resin (trade name Celoxide 2021, manufactured by Daicel Chemical Industries, Ltd.) and 3 parts by weight of a cationic photopolymerization initiator CP170 (Asahi Denka Kogyo Co., Ltd.) The product is applied to a thickness of about 5 μm with a bar coater and about 300 mJ / cm.
² UV light was applied to cure. Furthermore, it heated at about 200 degreeC in the vacuum oven for 1 hour, and formed the organic coating layer. Further, a silicon oxide film and a transparent conductive layer were formed in the same manner as in Example 2.

(Example 5)
100 parts by weight of an alicyclic epoxy resin (E-BP manufactured by Daicel Chemical Industries, Ltd.) represented by the chemical formula (4) on one surface of a plastic sheet (thickness: about 0.1 mm) prepared in the same manner as in Example 1. And an organic coating resin composition comprising 3 parts by weight of a cationic photopolymerization initiator CP170 (manufactured by Asahi Denka Kogyo Co., Ltd.) with a bar coater to a thickness of about 5 μm, and irradiated with UV light of about 300 mJ / cm ^2. Cured. Furthermore, it heated at about 200 degreeC in the vacuum oven for 1 hour, and formed the organic coating layer. Further, a silicon oxide film and a transparent conductive layer were formed in the same manner as in Example 2.

(Example 6)
A plastic sheet (thickness of about 0.1 mm) prepared in the same manner as in Example 1 is represented by the chemical formula (5)
100 parts by weight of an alicyclic epoxy resin (E-DOA manufactured by Daicel Chemical Industries, Ltd.) in which X of — (CH ₃ ) ₂ — is represented, and 3 parts by weight of a cationic photopolymerization initiator CP170 (manufactured by Asahi Denka Kogyo) The organic coating resin composition consisting of the following is applied to a thickness of about 5 μm with a bar coater, and about 300 mJ / cm.
² UV light was applied to cure. Furthermore, it heated at about 200 degreeC in the vacuum oven for 1 hour, and formed the organic coating layer. Further, a silicon oxide film and a transparent conductive layer were formed in the same manner as in Example 2.

(Comparative Example 1)
A plastic sheet having a thickness of 0.1 mm was prepared in the same manner as in Example 1, and no organic coating layer (c) was formed.

(Evaluation method)
Various characteristics of the sheet-like plastic substrate (optical sheet) produced in the above example were measured by the following evaluation methods.

a) Average linear expansion coefficient After increasing the temperature from 30 ° C. to 250 ° C. at a rate of 5 ° C. per minute in a nitrogen atmosphere using a TMA / SS120C type thermal stress strain measuring device manufactured by Seiko Electronics Co., Ltd. Once cooled to 0 ° C., the temperature was increased again at a rate of 5 ° C. per minute, and the value at 30 ° C. to 150 ° C. was measured and determined.

For the measurement, an independently designed quartz tension chuck (material: quartz, coefficient of linear expansion of 0.5 ppm) was used. Commonly used Inconel chucks have a high linear expansion per se and defects in the sample support form. When applied to thick sheets exceeding 100 μm, the linear expansion coefficient is larger than the result measured in the compression mode. Or the measurement variation becomes large. Therefore, we decided to design a quartz tensile chuck and use it to measure the linear expansion coefficient. By using this tension chuck, it has been confirmed that it can be measured with a value almost the same as that measured in the compression mode.
b) Observation with a surface irregularity surface structure analysis microscope New View 5032 (manufactured by Zygo Corporation) at a field of view: 1.44 mm × 1.08 mm, and the heights of the highest and lowest points of adjacent fiber cloths were measured. In the measurement results, Examples 2 to 6 are values on the surface on which the indium tin oxide film is formed, and Examples 1 and Comparative Example 1 are measured on both surfaces and set to the smaller value.

c) Parallel light transmittance The parallel light transmittance at 550 nm was measured with a spectrophotometer U3200 (manufactured by Hitachi, Ltd.).
The results of evaluating the samples obtained in the examples and comparative examples by these evaluation methods are shown in Table 1 below.

Claims (6)

It is an optical sheet in which one or more layers of a 1 to 30 μm thick organic coat layer (c) are laminated on at least one side of a sheet (A) comprising a transparent resin (a) and a glass fiber (b),
The surface roughness of the surface of the organic coating layer (c) was laminated an optical sheet is 150nm or less,
Curing including the transparent resin (a) as an epoxy resin and the organic coat layer (c) as a constituent component of one or more selected from alicyclic epoxy resins represented by the following chemical formula (4) or (5) An optical sheet that is a resin.


(In the formula, X is an oxygen atom, a sulfur atom, —SO—, —SO ₂ —, —CH ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ) ₂ —). ) 30-150 optical sheet of claim 1, wherein an average linear expansion coefficient is 40ppm or less in ° C.. The optical sheet according to claim 1 , wherein the optical sheet has a thickness of 50 to 2000 μm. The optical sheet according to any one of claims 1 to 3 , wherein an inorganic oxide is laminated as the gas barrier layer (e). The optical sheet according to any one of claims 1 to 4 , wherein the outermost layer is provided with a conductive layer (d) containing indium oxide as a main component. A plastic substrate for a display element or an active matrix display substrate produced using the optical sheet according to any one of claims 1 to 5 .