JP2009244756A - Transparent substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent substrate having a high surface flatness and an excellent blocking property against gas such as water vapor. <P>SOLUTION: The transparent substrate comprises a transparent laminated plate 1 manufactured by impregnating and curing a resin composition, of which the refractive index is adjusted to approximate that of a glass fiber by mixing a high refractive index resin having a refractive index larger than that of the glass fiber with a low refractive index resin having a refractive index smaller than that of the glass fiber, into a glass fiber base material. A transparent flattening layer 2 is formed on the transparent laminated plate 1 for forming a flat surface by painting a coating agent containing an inorganic filler. By painting the coating agent, the flattening layer 2 is formed in a state that the irregularity of the transparent laminated plate 1 is filled up and flattened, thus the surface flatness is enhanced. Further, the flattening layer 2 contains an inorganic filler, thus the curing and contraction of the flattening layer 2 is reduced, the flattening effect is enhanced and the blocking property of the flattening layer 2 against gas such as water vapor is improved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a transparent substrate used for a liquid crystal display or the like.

  A transparent substrate formed of a transparent laminated plate has been studied as a material to replace a glass plate in flat panel displays such as a liquid crystal display, a plasma display, and an EL display (for example, Patent Document 1).

  As an example of such a transparent laminate used as a transparent substrate, a prepreg is prepared by impregnating a substrate made of glass fiber such as glass cloth with a transparent thermosetting resin having a refractive index similar to that of glass fiber. What was produced by heat-press-molding can be mentioned. An epoxy resin is generally used as the transparent thermosetting resin. In order to approximate the refractive index of the resin to the refractive index of the glass fiber, an epoxy resin having a higher refractive index than the glass fiber and a refractive index higher than that of the glass fiber are used. A resin composition is used in which a small epoxy resin is mixed and the mixing ratio is adjusted so that the refractive index approximates the refractive index of the glass fiber. Thus, by combining the refractive index of the glass fiber of the base material and the matrix resin, the refraction of light in the transparent laminate can be suppressed and used as a transparent substrate of a display excellent in visibility.

FIG. 4 shows an example of a schematic configuration of a liquid crystal display manufactured using a transparent substrate A formed by such a transparent laminated plate. A pair of transparent substrates A are arranged in parallel, and the space between the transparent substrates A is shown. The drive element 10 is mounted on the board. The drive element 10 includes a pixel electrode 11 and TFT 12 provided on one transparent substrate A, a common electrode 13 provided on the other transparent substrate A, and liquid crystal molecules 14 filled between the transparent substrates A. It is what is done.
JP 2004-307851 A

  In the liquid crystal display as described above, if the distance between the transparent substrates A arranged opposite to each other is non-uniform, the thickness of the liquid crystal molecules 14 filled becomes non-uniform, and the orientation of the liquid crystal molecules 14 May be partially disturbed and light scattering may occur. Further, the liquid crystal molecules 14 are liable to deteriorate when water vapor, oxygen, or the like acts on them, and the life of the liquid crystal display may be shortened by the action of water vapor or the like.

  However, since the transparent substrate A is formed by a transparent laminated plate prepared by impregnating and curing a resin on a glass base material, it is difficult to form a surface with high smoothness like a glass substrate. The unevenness of the glass substrate formed by cloth or the like appears on the surface, and the smoothness tends to be lowered. Accordingly, when such a transparent substrate A is used as a substrate for a liquid crystal display, the interval between the transparent substrates A arranged opposite to each other becomes non-uniform, and the alignment of the liquid crystal molecules 14 that are filled is disturbed. There is a problem that scattering may occur and a clear image may not be obtained.

  In addition, the transparent substrate A is formed by a transparent laminated plate prepared by impregnating and curing a resin on a glass substrate, and has a high gas barrier property like a glass plate because the resin is used as a matrix. is not. Therefore, when such a transparent substrate A is used as a substrate for a liquid crystal display, it is not possible to completely block gas such as water vapor or oxygen from passing through the transparent substrate A, and water vapor or oxygen acts on the liquid crystal molecules 14. There was a problem that it may deteriorate.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a transparent substrate having a high surface smoothness and a high barrier property to gas such as water vapor.

  The transparent substrate according to the present invention is a mixture of a high refractive index resin having a refractive index larger than that of glass fiber and a low refractive index resin having a refractive index smaller than that of glass fiber so that the refractive index approximates that of glass fiber. The transparent smoothed layer 2 for forming a smooth surface is provided with a transparent laminate 1 prepared by impregnating and curing a glass fiber base material with a resin composition adjusted to contain an inorganic filler. It is characterized by being formed on the surface of the transparent laminate 1 by coating with a coating agent.

  According to this invention, the smoothing layer 2 can be formed in a state in which the unevenness of the transparent laminate 1 is filled and flattened by coating with a coating agent, and the smoothness of the surface can be improved. In addition, since the smoothing layer 2 contains an inorganic filler, the curing shrinkage of the smoothing layer 2 can be reduced to obtain a higher smoothing effect, and a gas such as water vapor from the smoothing layer 2 can be obtained. It is possible to improve the barrier property of the gas and prevent gas from permeating.

  In the present invention, the inorganic filler is at least one selected from silicon dioxide, titanium oxide, zirconium oxide, and zinc oxide, and the gas barrier property of the smoothing layer 2 can be increased. It can be done.

  Moreover, this invention is characterized by laminating | transparent the smooth smoothing layer 3 which does not contain a filler on the surface of said smoothing layer 2 containing an inorganic filler.

  According to the present invention, the surface smoothness can be further improved by the transparent smoothing layer 3 containing no filler.

  In addition to the above smoothing layers 2 and 3, the present invention is characterized in that a transparent gas barrier layer 4 made of at least one material selected from silicon dioxide, silicon oxynitride, and silicon nitride is formed. Is.

  According to the present invention, the gas barrier layer 4 can obtain a higher effect of blocking gas such as water vapor.

  In the present invention, the smoothing layers 2 and 3 have a glass transition point of 200 ° C. or higher.

  According to the present invention, a transparent substrate having high heat resistance can be obtained.

  Further, the present invention is characterized in that the surface roughness (Ra) formed by the smoothing layers 2 and 3 is 30 nm or less.

  When the smoothness of the surface of the transparent substrate is less than or equal to the roughness (Ra) 30 nm, the liquid crystal molecules 14 are disturbed in alignment when the transparent substrates are arranged in parallel and filled with the liquid crystal molecules 14 of the display driving element 10. It is possible to prevent the occurrence of light scattering more effectively and to prevent scattering of light, and a clear image can be obtained.

Further, the present invention is characterized in that the water vapor transmission rate is 0.1 g / m ² day or less.

When the water vapor transmission rate of the transparent substrate is 0.1 g / m ² day or less, it is possible to effectively prevent the gas such as water vapor from acting on the driving element 10 of the display and deteriorating the liquid crystal molecules 14 and the like. It is.

  According to the present invention, the smoothing layer 2 can be formed in a state where the unevenness of the transparent laminate 1 is filled and flattened by coating with a coating agent, and the smoothness of the surface can be improved. It is. In addition, since the smoothing layer 2 contains an inorganic filler, the curing shrinkage of the smoothing layer 2 can be reduced to obtain a higher smoothing effect, and a gas such as water vapor from the smoothing layer 2 can be obtained. It is possible to improve the barrier property of the gas and prevent gas from permeating.

  Hereinafter, the best mode for carrying out the present invention will be described.

  First, the transparent laminated board used in this invention is demonstrated. This transparent laminate is adjusted so that the refractive index approximates the refractive index of the glass fiber by mixing a high refractive index resin having a higher refractive index than that of the glass fiber and a low refractive index resin having a lower refractive index than that of the glass fiber. The resin composition prepared is impregnated into a glass fiber substrate and cured.

  It is preferable to use a cyanate ester resin as a resin having a higher refractive index than the glass fiber. The cyanate ester resin is obtained by polymerization of a cyanate ester compound having two or more cyanate groups in one molecule by generating a triazine ring by trimerization. Examples of the cyanate ester compound include 2,2-bis ( Aromatic cyanate ester compounds such as 4-cyanatophenyl) propane, bis (3,5-dimethyl-4-cyanatophenyl) methane, 2,2-bis (4-cyanatophenyl) ethane, and derivatives thereof Can be used. These may be used alone or in combination of a plurality of types. This cyanate ester resin has a rigid molecular skeleton, and therefore imparts a high glass transition temperature to the cured product. Further, since cyanate ester resin is solid at normal temperature, it becomes easy to dry by touch when preparing a prepreg by impregnating a resin composition into a glass fiber substrate and drying it as described later. The prepreg is easy to handle.

  Here, when the refractive index of the glass fiber is, for example, 1.562, the cyanate ester resin used as the high refractive index resin preferably has a refractive index of around 1.6. When the refractive index of the glass fiber is n, n + 0 It is desirable that it is in the range of 0.03 to n + 0.06. In the present invention, the refractive index of the resin refers to the refractive index in the state of the cured resin, and is a value tested by ASTM D542.

  On the other hand, as the resin having a lower refractive index than the glass fiber, any epoxy resin can be used as long as it has a low refractive index, but it is preferable to use a hydrogenated bisphenol type epoxy resin. When the refractive index of the glass fiber is 1.562, for example, the low refractive index epoxy resin preferably has a refractive index of around 1.5, where n−0.04, where n is the refractive index of the glass fiber. It is desirable to be in the range of ˜n−0.08.

  In the low refractive index hydrogenated bisphenol type epoxy resin, as the bisphenol type, bisphenol F type, bisphenol S type and the like can be used in addition to the bisphenol A type.

  Further, as the hydrogenated bisphenol type epoxy resin having a low refractive index, it is preferable to use a solid type hydrogenated bisphenol type epoxy resin that is solid at room temperature. Liquid type hydrogenated bisphenol type epoxy resin that is liquid at room temperature can be used, but when preparing the prepreg, it can only be dried to a sticky state with the touch, and the prepreg is easy to handle. Since it becomes worse, it is preferable to use a solid-type hydrogenated bisphenol-type epoxy resin. Furthermore, it is possible to use other than the hydrogenated bisphenol type epoxy resin as the low refractive index epoxy resin. For example, an epoxy resin containing 1,2-epoxy-4- (2-oxiranyl) cyclohexane is used in combination. be able to. This epoxy resin is used in combination to finely adjust the refractive index, and is an optimal resin for facilitating the production of a transparent laminate because it is solid at room temperature.

  Then, the above-described high refractive index cyanate ester resin is mixed with an epoxy resin such as a low refractive index hydrogenated bisphenol type epoxy resin to prepare and use a resin composition that approximates the refractive index of glass fiber. is there. The mixing ratio of the high refractive index cyanate ester resin and the low refractive index epoxy resin is arbitrarily adjusted so as to approximate the refractive index of the glass fiber. Here, it is desirable that the refractive index of the resin composition be as close as possible to the refractive index of the glass fiber. It is preferable to do this.

  The resin composition is preferably prepared such that the cured resin has a glass transition temperature (Tg) of 170 ° C. or higher. When the glass transition temperature is 170 ° C. or higher, the heat resistance of the transparent laminate can be increased. The upper limit of the glass transition temperature is not particularly set, but practically about 280 ° C. is the upper limit of the glass transition temperature. The glass transition temperature can be adjusted by changing the blending ratio of the cyanate ester resin in the resin composition, and depends on the type of low refractive index resin used together. If the cyanate ester resin is about 30% by mass or more in the resin component, the glass transition temperature of the resin composition can be adjusted to 170 ° C. or more.

  Furthermore, a curing initiator (curing agent) can be blended in the resin composition. An organic metal salt can be used as the curing initiator. Examples of the organic metal salt include salts of an organic acid such as octanoic acid, stearic acid, acetylacetonate, naphthenic acid, and salicylic acid with a metal such as Zn, Cu, and Fe. These may be used alone or in combination of two or more. Among them, zinc octoate is preferable. By using zinc octoate as the curing initiator, the glass transition temperature of the cured resin can be increased. The content of the organic metal salt such as zinc octoate in the resin composition is not particularly limited, but is preferably in the range of 0.01 to 0.1 PHR.

  A cationic curing agent can also be used as the curing initiator. Thus, by using a cationic curing agent, the transparency of the resin can be enhanced. The cationic curing agent is not particularly limited, and aromatic sulfonium salts, aromatic iodonium salts, ammonium salts, aluminum chelates, boron trifluoride amine complexes, and the like can be used. The content of the cationic curing agent in the resin composition is not particularly limited, but is preferably in the range of 0.2 to 3.0 PHR.

  Further, a curing catalyst such as a tertiary amine such as triethylamine or triethanolamine, 2-ethyl-4-imidazole, 4-methylimidazole, 2-ethyl-4-methyl-imidazole (2E4MZ) may be used as a curing initiator. it can. The content of the curing catalyst in the resin composition is not particularly limited, but is preferably in the range of 0.5 to 5 PHR.

  As described above, a resin composition can be prepared by blending an epoxy resin such as a high refractive index cyanate ester resin, a low refractive index hydrogenated bisphenol type epoxy resin, and a curing initiator. This resin composition is used as a resin varnish after being dissolved or dispersed in a solvent as required. The solvent is not particularly limited, but benzene, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, acetone, methanol, ethanol, isopropyl alcohol, 2-butanol, ethyl acetate, butyl acetate, propylene glycol monomethyl ether, Propylene glycol monomethyl ether acetate, diacetone alcohol, N, N′-dimethylacetamide and the like can be used.

  On the other hand, the glass fiber is preferably E glass or NE glass in view of the effect of increasing the impact resistance of the transparent laminate. E glass is also called non-alkali glass and is a glass that is widely used as a glass fiber for resin reinforcement, and NE glass is NewE glass. Moreover, it is preferable to surface-treat glass fiber with the silane coupling agent normally used as a glass fiber processing agent in order to improve impact resistance. The refractive index of the glass fiber is preferably in the range of 1.55 to 1.57, and more preferably in the range of 1.555 to 1.565. If the refractive index of glass fiber is this range, the transparent laminated board excellent in visibility can be obtained. As the glass fiber base material, a glass fiber woven fabric or non-woven fabric can be used.

  A prepreg can be prepared by impregnating a glass fiber base material with a varnish of a resin composition, heating and drying. The drying conditions are not particularly limited, but a drying temperature of 100 to 160 ° C. and a drying time of 1 to 10 minutes are preferable.

  Next, one or a plurality of the prepregs are stacked and heated and pressed to cure the resin composition, thereby obtaining a transparent laminate. The conditions for the heat and pressure molding are not particularly limited, but a temperature range of 150 to 200 ° C., a pressure of 1 to 4 MPa, and a time of 10 to 120 minutes are preferable.

  In the transparent laminate obtained as described above, a resin matrix formed by polymerizing an epoxy resin such as a high refractive index cyanate ester resin and a low refractive index hydrogenated bisphenol type epoxy resin is a cyanate ester resin. By containing the glass, a glass transition temperature is high, and a transparent laminate having excellent heat resistance can be obtained. In addition, epoxy resins such as cyanate ester resin and hydrogenated bisphenol type epoxy resin are all excellent in transparency, and a transparent laminate having high transparency can be obtained. In this transparent laminated plate, the glass fiber base material content is preferably in the range of 25 to 65% by mass, and within this range, high impact resistance can be obtained due to the reinforcing effect of the glass fiber. Sufficient transparency can be obtained.

  Here, as a glass fiber base material, in order to obtain high transparency, it is preferable to use a plurality of thin ones in a stacked manner. Specifically, it is preferable to use a glass fiber substrate having a thickness of 50 μm or less and to use two or more glass fiber substrates having a thickness of 50 μm or less. Although the minimum of the thickness of a glass fiber base material is not specifically limited, About 10 micrometers is a practical minimum. The number of glass fiber substrates is not particularly limited, but about 20 is the practical upper limit. When producing a transparent laminate using a plurality of glass fiber base materials in this way, each glass fiber base material is impregnated with a resin composition and dried to produce a prepreg, and a plurality of the prepregs are stacked and heated. A transparent laminate can be obtained by pressure molding, but a prepreg is produced by impregnating and drying a resin composition in a state where a plurality of glass fiber base materials are stacked, and this prepreg is heated and pressure-molded. A transparent laminate may be obtained.

  And the transparent substrate A which concerns on this invention as shown in FIG. 1 can be obtained by forming the transparent smoothing layer 2 on the surface of the transparent laminated board 1 produced as mentioned above.

  The smoothing layer 2 is formed by coating the surface of the transparent laminate 1 with a coating agent containing an inorganic filler.

  The binder material for the coating agent is not particularly limited. For example, any material such as acrylic resin, urethane resin, epoxy resin, polyester resin, polyvinyl alcohol, ethylene vinyl alcohol copolymer, polyamide, and cellulose can be used. Can be used.

  Also, the inorganic filler is not particularly limited, but it is preferable to use one selected from silicon dioxide, titanium oxide, zirconium oxide, and zinc oxide. Among these, one is used alone, and two or more are used. Can also be used together. In particular, among these inorganic fillers, titanium oxide, zirconium oxide, and zinc oxide have an ultraviolet absorbing action, and therefore, the use of these can prevent discoloration of the transparent substrate A. The particle size of the inorganic filler is not particularly limited, but the average particle size is preferably in the range of 3 to 100 nm, and more preferably in the range of 3 to 20 nm. In the present invention, the average particle diameter is a value measured by a laser diffraction / scattering method.

  Although the compounding quantity of the inorganic filler in a coating agent is not specifically limited, It is preferable to set so that it may become the range of 10-70 mass% in solid content of a coating agent. If the blending amount of the inorganic filler is less than this range, the effect of blending the inorganic filler cannot be sufficiently obtained. Conversely, if the amount of the inorganic filler exceeds this range, the viscosity of the coating agent becomes high and it becomes difficult to paint with a uniform thickness.

  And the smoothing layer 2 can be formed by apply | coating this coating agent to the surface of the transparent laminated board 1, heating and drying, and also making it harden | cure. The coating agent can be applied using an appropriate method such as spraying, gravure printing, roll coating, spin coating, or bar coating. Among these, printing such as gravure is preferable because it can be applied uniformly with a thin film thickness. The thickness of the smoothing layer 2 is not particularly limited, but is preferably in the range of 1 to 10 μm. If the film thickness of the smoothing layer 2 is less than 1 μm, the effect of smoothing the surface of the transparent substrate A becomes insufficient. Conversely, if it exceeds 10 μm, the transparency of the smoothing layer 2 may be reduced.

  In the transparent substrate A formed by laminating the smoothing layer 2 on the surface of the transparent laminate 1 as described above, since the smoothing layer 2 is formed by coating with a coating agent, the transparent laminate 1 The transparent substrate A having a high smoothness can be obtained by the smoothing layer 2. Further, since the smoothing layer 2 contains an inorganic filler, it is possible to reduce curing shrinkage when the smoothing layer 2 is cured by applying a coating agent, and to obtain higher smoothness. It is something that can be done. Thus, by increasing the smoothness of the surface of the transparent substrate A, when the liquid crystal molecules 14 of the driving element 10 are filled with the pair of transparent substrates A arranged in parallel as shown in FIG. The interval between the electrodes can be set to a uniform size, the liquid crystal molecules 14 can be prevented from being disturbed in alignment, and light scattering can be prevented from occurring. Can be produced.

  As for the smoothness of the surface of the transparent substrate A formed by the smoothing layer 2, the surface roughness Ra is desirably 30 nm or less. When the surface roughness Ra is 30 nm or less, the interval between the transparent substrates A can be set more uniformly, and the liquid crystal molecules 14 are more reliably prevented from being disturbed in alignment, and light scattering occurs. It is possible to prevent this. Since the smaller the surface roughness Ra is, the lower the surface roughness Ra is not particularly set.

  In addition, since the smoothing layer 2 contains an inorganic filler as described above, it is possible to improve the barrier property of gases such as water vapor and oxygen that pass through the smoothing layer 2, Gases such as oxygen can be blocked by the smoothing layer 2 and these gases can be prevented from passing through the transparent substrate A. Therefore, when the display driving element 10 is mounted on the transparent substrate A, it is possible to prevent these gases from acting on the driving element 10 and deteriorating the liquid crystal molecules 14 of the driving element 10.

The gas permeability of the transparent substrate A formed by laminating the smoothing layer 2 on the transparent laminate 1 is desirably a water vapor permeability (WVTR) of 0.1 g / m ² · day or less. When the water vapor transmission rate (WVTR) of the transparent substrate A is 0.1 g / m ² · day or less, it is possible to effectively prevent a gas such as water vapor from acting on the driving element 10 and deteriorating. . The lower the water vapor transmission rate (WVTR), the better. The lower limit is not particularly set. In the present invention, the water vapor transmission rate is a value measured by a method according to JIS Z 0208 (1976).

  Moreover, after forming the smoothing layer 2 containing an inorganic filler on the surface of the transparent laminated board 1 as mentioned above, the coating agent which does not contain an inorganic filler is applied to the surface of this smoothing layer 2, and an inorganic filler is applied. You may make it form the transparent smoothing layer 3 which does not contain as shown in FIG. Thus, the smoothness of the surface of the transparent substrate A can be further improved by laminating and forming the smoothing layer 3 containing no inorganic filler on the smoothing layer 2 containing the inorganic filler. It is.

  As the coating agent for forming the smoothing layer 3 containing no inorganic filler, the coating agent for forming the smoothing layer 2 described above can be used without blending the inorganic filler. The film thickness of the smoothing layer 3 not containing the inorganic filler is not particularly limited, but is preferably in the range of 0.1 to 10 μm. The film thickness of the smoothing layer 3 is 0. If it is less than μm, the effect of forming the smoothing layer 3 containing no inorganic filler becomes insufficient. Conversely, if it exceeds 10 μm, the transparency of the smoothing layer 3 may be lowered.

  Here, the smoothing layer 2 containing the inorganic filler or the smoothing layer 3 containing no inorganic filler preferably has a glass transition point (Tg) of 200 ° C. or higher. As described above, when the glass transition point of the smoothing layers 2 and 3 is 200 ° C. or higher, the heat resistance of the smoothing layers 2 and 3 can be improved and a transparent substrate A having high heat resistance can be obtained. It is. The upper limit of the glass transition point is not particularly set, but about 300 ° C. is practically the upper limit of the glass transition point.

  In addition to the smoothing layers 2 and 3 as described above, a transparent gas barrier layer 4 can be provided. For example, as shown in FIG. 3 (a), after the smoothing layer 2 is formed on the surface of the transparent laminated plate 1, the gas barrier layer 4 may be provided on the smoothing layer 2 and laminated. The gas barrier layer 4 may be formed on the surface of the transparent laminate 1 as shown in FIG. 2 and then the smoothing layer 2 may be provided thereon for lamination. Further, as shown in FIG. 3C, the smoothing layer 2 may be provided on one surface of the transparent laminate 1 and the gas barrier layer 4 may be provided on the other surface.

  In this way, by providing the gas barrier layer 4 in addition to the smoothing layers 2 and 3, gas such as water vapor can be blocked by the gas barrier layer 4, and the gas blocking performance of the transparent substrate A is improved. It is something that can be done. In particular, as shown in FIG. 3A, by forming the gas barrier layer 4 on the smoothing layers 2 and 3, a high effect of smoothing the surface can be obtained.

  The gas barrier layer 4 can be formed of a material selected from silicon dioxide, silicon oxynitride, and silicon nitride. The gas barrier layer 4 can be formed using a vapor deposition method, for example, a chemical vapor deposition method (CVD) such as thermal CVD, plasma CVD, or laser CVD, vacuum deposition, ion plating, or sputtering. Physical vapor deposition (PVD) such as laser ablation can be employed. The film thickness of the gas barrier layer 4 is not particularly limited, but is preferably in the range of about 10 to 200 nm.

  Next, the present invention will be specifically described with reference to examples.

Example 1
As a high refractive index resin, solid cyanate ester resin (“BADCy” manufactured by Lonza, 2,2-bis (4-cyanatophenyl) propane: refractive index 1.59) is 52 parts by mass, as a low refractive index resin. 48 parts by mass of an epoxy resin containing solid 1,2-epoxy-4- (2-oxiranyl) cyclohexane (“EHPE3150” manufactured by Daicel Chemical Industries, Ltd .: refractive index 1.51) was added, and further curing started 0.02 parts by mass of zinc octoate was blended as an agent, 50 parts by mass of toluene and 50 parts by mass of methyl ethyl ketone were added thereto, and the mixture was stirred and dissolved at a temperature of 70 ° C. to prepare a varnish of the resin composition. The refractive index of the cured product of this resin composition was 1.56.

  Next, a glass fiber cloth having a thickness of 25 μm (Asahi Kasei Electronics Co., Ltd., product number “1037”, E glass, refractive index 1.562) is impregnated with the varnish of the above resin composition and heated at 150 ° C. for 5 minutes. Thus, the solvent was removed and the resin was semi-cured to prepare a prepreg.

  Then, two sheets of this prepreg are stacked, sandwiched between release-molded glass plates, set in a press machine, and heated and pressed under conditions of 170 ° C., 2 MPa, 15 minutes, whereby the resin content is 63% by mass. A transparent laminate 1 having a thickness of 80 μm was obtained.

  On the other hand, an ultraviolet curable acrylic resin (“X-12-2427D” manufactured by Shin-Etsu Chemical Co., Ltd., glass transition point 80 ° C.) containing 50% by mass of silicon dioxide particles having an average particle diameter of 10 nm is used as a coating agent. The surface of the plate 1 was painted. The coating is applied by a gravure coating method using a gravure with 90 lines / inch, under the condition of a conveyance speed of 5 m / min, 35 ° C. for 12 seconds, 60 ° C. for 12 seconds, 120 ° C. for 12 seconds, 130 After drying at 20 ° C. for 12 seconds, it was performed by irradiating and curing ultraviolet rays to obtain a transparent substrate A in which a smoothing layer 2 having a thickness of 2 μm was formed on the surface of the transparent laminate 1 (see FIG. 1).

(Example 2)
Using the transparent substrate A obtained in Example 1, a smoothing layer 3 containing no filler was formed on the smoothing layer 2 containing a silicon dioxide filler by the following method.

  As a coating agent, an ultraviolet curable acrylic resin containing no filler (“HC202” manufactured by Adeka Co., Ltd., glass transition point 210 ° C.) was used. Then, the transparent substrate A obtained in Example 1 is attached to a lead film and supplied, and a gravure coating method is applied to the surface of the smoothing layer 2 of the transparent substrate A by a gravure coating method. Was applied under the condition of a conveyance speed of 5 m / min. Next, after drying at 35 ° C. for 12 seconds, at 60 ° C. for 12 seconds, at 120 ° C. for 12 seconds, and at 130 ° C. for 12 seconds, it was cured by irradiating with ultraviolet rays to form a smoothing layer 3 having a thickness of 1 μm. .

  Thus, the transparent substrate A which provided the smoothing layer 2 containing a silicon dioxide filler and the smoothing layer 3 which does not contain the filler on the transparent laminated board 1 was obtained (refer FIG. 2).

(Example 3)
Using the transparent substrate A obtained in Example 1, the surface of the smoothing layer 2 containing the silicon dioxide filler, using a vacuum film formation apparatus “SUPLaDUO” manufactured by Chugai Kogyo Kogyo Co., Ltd. A gas barrier layer 4 was formed.

SiO was used as the vapor deposition material, and a gas barrier layer 4 made of a SiO ₂ film having a thickness of 100 nm was formed under the conditions of a set pressure of 0.12 Pa, an oxygen introduction amount of 120 sccm, a film forming time of 60 seconds, and a discharge output of 5 kw.

  Thus, the transparent substrate A which provided the smoothing layer 2 containing a silicon dioxide filler and the gas barrier layer 4 on it on the transparent laminated board 1 was obtained (FIG. 3 (a)).

Example 4
Solidify UV curable acrylic resin (“HC202” manufactured by Adeka Co., Ltd., glass transition point 210 ° C.) with a zirconia particle dispersion (“ZRDMA20WT20% -G22” manufactured by CI Kasei Co., Ltd., average particle diameter of zirconia particles 20 nm). A coating agent was prepared by blending 45% by mass in minutes.

  And this coating agent was apply | coated to the surface of the transparent laminated board 1 produced in Example 1 by the gravure coating method on the conditions of the conveyance speed of 5 m / min using the gravure of 90 lines / inch, and 35 degreeC. The film was dried for 12 seconds, 60 ° C. for 12 seconds, 120 ° C. for 12 seconds, and 130 ° C. for 12 seconds, and then cured by irradiation with ultraviolet rays to form a smoothing layer 2 having a thickness of 2 μm.

  Thus, the transparent substrate which formed the smoothing layer 2 containing a zirconia filler on the surface of the transparent laminated board 1 was obtained (refer FIG. 1).

(Example 5)
Solid titanium oxide particle dispersion (“TS-019” manufactured by Teika Co., Ltd., average particle diameter of titanium oxide particles 20 nm) in UV curable acrylic resin (“HC202” manufactured by Adeka Co., Ltd., glass transition point 210 ° C.) A coating agent was prepared by blending 45% by mass in minutes.

  And this coating agent was apply | coated to the surface of the transparent laminated board 1 produced in Example 1 by the gravure coating method on the conditions of the conveyance speed of 5 m / min using the gravure of 90 lines / inch, and 35 degreeC. The film was dried for 12 seconds, 60 ° C. for 12 seconds, 120 ° C. for 12 seconds, and 130 ° C. for 12 seconds, and then cured by irradiation with ultraviolet rays to form a smoothing layer 2 having a thickness of 2 μm.

  Thus, the transparent substrate A which formed the smoothing layer 2 containing a titanium oxide filler on the surface of the transparent laminated board 1 was obtained (refer FIG. 1).

(Example 6)
Solid zinc-oxide dispersion (“TS-034” manufactured by Teika Co., Ltd., average particle size of zinc oxide particles 20 nm) in an ultraviolet curable acrylic resin (“HC202” manufactured by Adeka Co., Ltd., glass transition point 210 ° C.) A coating agent was prepared by blending 45% by mass in minutes.

  And this coating agent was apply | coated to the surface of the transparent laminated board 1 produced in Example 1 by the gravure coating method on the conditions of the conveyance speed of 5 m / min using the gravure of 90 lines / inch, and 35 degreeC. The film was dried for 12 seconds, 60 ° C. for 12 seconds, 120 ° C. for 12 seconds, and 130 ° C. for 12 seconds, and then cured by irradiation with ultraviolet rays to form a smoothing layer 2 having a thickness of 2 μm.

  Thus, the transparent substrate which formed the smoothing layer 2 containing the zinc oxide filler on the surface of the transparent laminated board 1 was obtained (refer FIG. 1).

(Comparative Example 1)
The transparent laminate 1 produced in Example 1 was used as it was without forming a smoothing layer.

(Comparative Example 2)
As a coating agent, an ultraviolet curable acrylic resin containing no filler (“HC202” manufactured by Adeka Co., Ltd., glass transition point 210 ° C.) was used. And this coating agent was apply | coated to the surface of the transparent substrate A obtained in Example 1 by the gravure coating method on the conditions of the conveyance speed of 5 m / min using gravure of 90 lines / inch, and 35 degreeC. The film was dried for 12 seconds, 60 ° C. for 12 seconds, 120 ° C. for 12 seconds, and 130 ° C. for 12 seconds, and then cured by irradiation with ultraviolet rays to form a smoothing layer 2 having a thickness of 6 μm.

  About the transparent substrate of said Examples 1-6 and Comparative Examples 1-2, surface discoloration Ra of the surface in which the smoothing layer was formed, water vapor transmission rate (WVTR), and the discoloration after a weather resistance test were evaluated. The results are shown in Table 1.

  Here, the surface roughness Ra is measured at three points in the vertical, horizontal and 45 ° bias directions by using a stylus type surface roughness meter “SURFCOM 130A” manufactured by Tokyo Seimitsu Co., Ltd. The average value of a total of nine measured values was taken as the Ra value.

  In addition, the weather resistance test is performed by irradiating for 1000 hours using a carbon arc type sunshine weatherometer (“WEL-SUN-HCT” manufactured by Suga Test Co., Ltd.) in accordance with JIS K 5400 9-8. The color difference ΔE (JIS Z 8730) before and after the test was measured.

As can be seen from Table 1, in each of the examples in which the smoothing layer contains an inorganic filler, the discoloration is small, and in particular, TiO ₂ , ZrO ₂ , and ZnO having an ultraviolet absorbing action are used as the inorganic filler. The used Examples 4-6 had a small discoloration.

  In addition, the surface roughness Ra of each example is small and the surface smoothness is improved. In particular, in Example 2 in which a smoothing layer without a filler is laminated, the surface roughness Ra is 30 nm or less. And, the effect of improving the surface smoothness was high.

Further, each example has a low water vapor transmission rate, and in Example 3 in which a gas barrier layer is laminated, the water vapor transmission rate is 0.1 g / m ² day or less, and the effect of blocking moisture is high. It was something that could be done.

It is the schematic which shows an example of embodiment of this invention. It is the schematic which shows an example of other embodiment of this invention. An example of other embodiments of the present invention is shown, and (a) (b) (c) is a schematic diagram, respectively. It is a figure which shows schematic structure of a liquid crystal display.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent laminated board 2 Smoothing layer containing an inorganic filler 3 Smoothing layer which does not contain an inorganic filler 4 Gas barrier layer

Claims (7)

  A resin composition prepared by mixing a high refractive index resin having a refractive index higher than that of glass fiber and a low refractive index resin having a refractive index lower than that of glass fiber so that the refractive index approximates the refractive index of glass fiber. A transparent smoothing layer is provided with a transparent laminated plate made by impregnating and curing a glass fiber substrate, and the surface of the transparent laminated plate is coated with a coating agent containing an inorganic filler. A transparent substrate characterized by being formed.   The transparent substrate according to claim 1, wherein the inorganic filler is at least one selected from silicon dioxide, titanium oxide, zirconium oxide, and zinc oxide.   The transparent substrate according to claim 1 or 2, wherein a transparent smoothing layer not containing a filler is laminated on the surface of the smoothing layer containing an inorganic filler.   4. The transparent gas barrier layer made of at least one material selected from silicon dioxide, silicon oxynitride, and silicon nitride is formed in addition to the smoothing layer. The transparent substrate as described.   The transparent substrate according to any one of claims 1 to 4, wherein the smoothing layer has a glass transition point of 200 ° C or higher.   6. The transparent substrate according to claim 1, wherein the surface roughness (Ra) is 30 nm or less. The water vapor transmission rate is 0.1 g / m ² day or less, and the transparent substrate according to any one of claims 1 to 6.

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