JP2005037738A - Particle dispersed resin sheet, substrate for image display apparatus, and image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin sheet having excellent heat resistance and strength, high transmittance for light, and a light diffusing function. <P>SOLUTION: The particle dispersed resin sheet contains an epoxy resin having a terpene skeleton and a light diffusing agent having a refractive index different from that of the epoxy resin, with the light diffusing agent unevenly distributed in the thickness direction. The resin sheet having the light diffusing agent unevenly distributed in the thickness direction can be produced by spreading a coating liquid containing the above terpene-type epoxy resin and the light diffusing agent on a substrate, sedimenting or suspending the light diffusing agent in the spread layer, and hardening the layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a particle-dispersed resin sheet, various image display device substrates or solar cell substrates such as a liquid crystal cell substrate and an electroluminescence (EL) display substrate using the same, and various image display devices or the like using them. It relates to solar cells.

  As a liquid crystal cell substrate or EL display substrate in a liquid crystal display device or EL display device, a glass substrate has generally been used from the viewpoint of strength and heat resistance. However, in recent years, with the increase in size of various display devices as described above, it has been required to reduce the thickness and weight of the various substrates. Therefore, in place of a heavy and bulky glass substrate, it has been proposed and actually developed to use a resin sheet such as an epoxy-based resin as a substrate for the purpose of reducing the thickness and weight. 1). However, although the strength of such a resin sheet such as an epoxy resin is at a level that can be used, it may be broken, for example, during transportation or assembly of various display devices as compared with the glass substrate. For this reason, development of a resin sheet having even higher strength is required.

  Further, in the liquid crystal display device, for example, by attaching a light diffusion sheet containing transparent particles to the viewing side of the liquid crystal cell, glare caused by illumination light or the backlight built in the display device can be prevented and visually recognized. A method for improving the property is known (for example, see Patent Document 2). However, as described above, since the liquid crystal display device is required to be thin and light, instead of attaching the light diffusion sheet to the viewing side of the liquid crystal cell, for example, the light diffusion function is applied to the liquid crystal cell substrate itself. Is also being considered.

In recent years, with the development of satellite communication and mobile communication technologies, the demand for small portable information terminal devices is increasing. As for display devices mounted on many of the small portable information terminal devices, liquid crystal display devices are most frequently used in order to achieve thinning. In addition, since this display device is required to have, for example, low power consumption and high visibility under external light, a reflective liquid crystal display device is used more frequently than a transmissive liquid crystal display device. Yes. Further, it is desired that a display device used for such a small portable information terminal device achieves further reduction in thickness and weight and improves visibility.
Japanese Patent No. 3197716 JP-A-11-333866

  Accordingly, an object of the present invention is to provide a thin, lightweight, tough and hard-to-break resin sheet that prevents glare caused by, for example, illumination light or a backlight with a built-in display device, and a liquid crystal cell using the same The present invention provides a substrate for various image display devices such as a substrate and an EL display device substrate, and an image display device such as a liquid crystal display device and an organic EL display device using the substrate.

In order to achieve the above object, the present invention is a particle-dispersed resin sheet comprising an epoxy resin and a particulate light diffusing agent, wherein the light diffusing agent is dispersed,
The epoxy resin includes an epoxy resin having a terpene skeleton (hereinafter referred to as “terpene epoxy resin”),
The light diffusing agent is a light diffusing agent having a refractive index different from that of the epoxy resin,
The light diffusing agent is unevenly distributed in the thickness direction.

  Thus, the resin sheet of the present invention exhibits excellent toughness by including a terpene type epoxy resin, and even when applied to various display devices as described later, it is difficult to break and is lightweight. In addition, a display device or the like that exhibits not only thinning but also excellent strength can be obtained. Furthermore, since a light diffusing function is imparted by containing a light diffusing agent having a refractive index different from that of the terpene epoxy resin, the resin sheet itself can diffuse light incident on the sheet. Moreover, since the light diffusing agent is unevenly distributed in the thickness direction in the resin sheet, for example, when used as a liquid crystal cell substrate, the light diffusing agent is distributed only in a portion close to the liquid crystal layer in the liquid crystal cell. Can do. For this reason, for example, it is possible to prevent glare caused by illumination light or a backlight built in a liquid crystal display device to improve visibility, and to suppress excessive diffusion of light due to uneven distribution of the diffusing agent. Can provide.

  Further, by using such a resin sheet of the present invention, for example, a substrate for an image display device or a substrate for a solar cell of the present invention such as a liquid crystal cell substrate can be provided. Furthermore, these various substrates for image display devices For example, the image display device of the present invention such as a liquid crystal display device or an EL display device can be provided.

As described above, the resin sheet of the present invention is a particle-dispersed resin sheet containing an epoxy resin and a particulate light diffusing agent, wherein the light diffusing agent is dispersed,
The epoxy resin includes a terpene type epoxy resin,
The refractive index of the light diffusing agent is different from the refractive index of the epoxy resin,
The light diffusing agent is unevenly distributed in the thickness direction of the sheet.

  “The light diffusing agent is unevenly distributed” means that the light diffusing agent is unevenly distributed, and there is no light diffusing agent other than the portion where the light diffusing agent is unevenly distributed (the unevenly distributed portion). Even if it exists, it is sufficient if the density is relatively lower than that of the unevenly distributed portion.

  In the resin sheet of the present invention, the unevenly distributed portion of the light diffusing agent is not particularly limited, but it is preferable that the light diffusing agent is unevenly distributed on one surface side for the following reasons. When such a resin sheet is used as a liquid crystal cell substrate, for example, the sheet may be arranged so that the unevenly distributed surface of the light diffusing agent is on the liquid crystal side to be carried. With this arrangement, the light diffusing agent is in a state adjacent to the liquid crystal, and thus, for example, the display quality of the liquid crystal display device becomes clearer and glare can be suppressed.

  The uneven distribution site of the light diffusing agent in the resin sheet is preferably a region from one surface to 1/50 to 1/2 of the total thickness, more preferably 1/40 to 1/3, and particularly preferably. Is 1/30 to 1/4.

  In the present invention, examples of the terpene type epoxy resin include structures represented by the following chemical formula (1).

前記式において、ｎは重合度であって、０〜５の整数である。なお、テルペン型エポキシ樹脂は、ｎが異なるテルペン型エポキシ樹脂の混合物であってもよい。

In the above formula, n is the degree of polymerization and is an integer of 0-5. The terpene type epoxy resin may be a mixture of terpene type epoxy resins having different n.

  Among the terpene type epoxy resins, for example, those having an epoxy equivalent of 180 to 400 (g / eq) are preferable, more preferably an epoxy equivalent of 220 to 350 (g / eq), and particularly preferably an epoxy equivalent of 230 to 300 (g). / Eq).

  The epoxy resin may further contain other epoxy resins in addition to the terpene type epoxy resin.

  The other epoxy resin is not particularly limited, and examples thereof include bisphenol A type, bisphenol F type, bisphenol S type and bisphenol types such as water additives thereof, novolak types such as phenol novolak type and cresol novolak type, Nitrogen-containing ring type such as triglycidyl isocyanurate type and hydantoin type, aromatic type such as alicyclic type and aliphatic type, naphthalene type, low water absorption type such as glycidyl ether type and biphenyl type, dicyclo type, ester type , Ether ester type, or modified versions thereof can be used.

  Among these, when combined with the terpene type epoxy resin, for example, the heat resistance and toughness are exhibited in an excellent balance, and therefore the alicyclic epoxy resin is preferable.

  The alicyclic epoxy resin is not particularly limited. For example, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 1,2-bis (hydroxylmethyl) -1-butanol, 2-epoxy-4- (2-oxiranyl) cyclohexane adducts and the like. Among them, for example, since it is excellent in fluidity of coating liquid and heat resistance after curing, 3,4-epoxycyclohexylmethyl- 3,4-epoxycyclohexanecarboxylate is preferred.

  In the present invention, the content ratio of the terpene type epoxy resin is preferably in the range of 9 to 60% by weight, more preferably 14 to 40% by weight, and particularly preferably, with respect to the total epoxy resin. Is in the range of 20-30% by weight. If the content ratio of the terpene type epoxy resin is 9% by weight or more, for example, even more excellent toughness can be maintained, and the possibility of breakage during transportation or assembly of the liquid crystal display device can be sufficiently avoided. Moreover, if the said content rate is 60 weight% or less, for example, since the coating liquid for forming a resin sheet becomes the viscosity excellent in handling, and it is excellent also in fluidity | liquidity, coating becomes much simpler.

  For example, the epoxy resin may contain various additives as necessary. Examples of the additive include a curing agent, a curing accelerator, an anti-aging agent, a modifier, a surfactant, a dye, Conventionally known additives such as pigments, discoloration inhibitors, ultraviolet absorbers and the like can be mentioned. Any one of these additives may be added, or two or more of them may be used in combination.

  The curing agent is not particularly limited, and examples thereof include organic acid compounds such as tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, and methylhexahydrophthalic acid, ethylenediamine, propylenediamine, diethylenetriamine, and triethylenetetramine. And amine compounds such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone. Any one of these curing agents may be used, or two or more of them may be used in combination.

  In addition to the curing agent as described above, for example, amide compounds such as dicyandiamide and polyamide, hydrazide compounds such as dihydragit, methylimidazole, 2-ethyl-4-methylimidazole, ethylimidazole, isopropylimidazole, Imidazole compounds such as 2,4-dimethylimidazole, phenylimidazole, undecylimidazole, heptadecylimidazole, 2-phenyl-4-methylimidazole, methylimidazoline, 2-ethyl-4-methylimidazoline, ethylimidazoline, isopropylimidazoline Imidazoline compounds such as 2,4-dimethylimidazoline, phenylimidazoline, undecylimidazoline, heptadecylimidazoline, 2-phenyl-4-methylimidazoline, Examples include enol compounds, urea compounds, polysulfide compounds and the like.

  Furthermore, acid anhydride compounds and the like can be used as the curing agent, and such acid anhydride compounds are preferable from the viewpoint of, for example, discoloration prevention. Specific examples include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, nadic anhydride, glutaric anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic acid Anhydride, methylhexahydrophthalic anhydride, methyl nadic acid anhydride, dodecenyl succinic anhydride, dichlorosuccinic anhydride, benzophenone tetracarboxylic anhydride, chlorendic acid anhydride, methyl nadic acid anhydride, etc. It is done. Among these acid anhydride compounds, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic acid anhydride, etc. are colorless or light yellow. Preferred are those having a molecular weight of about 140 to about 200.

  The blending ratio of the epoxy resin and the curing agent is not particularly limited, but when an acid anhydride curing agent is used as the curing agent, for example, an acid anhydride equivalent relative to 1 equivalent of epoxy group of the epoxy resin. It is preferable to mix | blend so that it may become 0.5-1.5 equivalent, More preferably, it is 0.7-1.2 equivalent. If the blending amount of the acid anhydride is 0.5 equivalents or more, the hue after curing is further excellent, and if it is 1.5 equivalents or less, sufficient moisture resistance can be maintained. In addition, when using another hardening | curing agent, or when using together 1 type, or 2 or more types of hardening | curing agents, it can mix | blend according to the above ratios, for example.

  The curing accelerator is not particularly limited, and examples thereof include tertiary amines, imidazoles, quaternary ammonium salts, organometallic salts, phosphorus compounds, urea compounds, and the like. Phosphorus compounds are preferred. These curing accelerators may be, for example, one type or a combination of two or more types.

  The mixing ratio of the curing accelerator is not particularly limited, and can be appropriately determined according to the amount and type of the epoxy resin, for example. Specifically, the curing accelerator is preferably, for example, 0.05 to 7.0 parts by weight, more preferably 0.2 to 3.0 parts by weight with respect to 100 parts by weight of the epoxy resin. It is. When the blending amount of the curing accelerator is 0.05 parts by weight or more, a sufficient curing accelerating effect can be obtained, and when it is 7.0 parts by weight or less, the hue after curing is further excellent. It becomes.

  Although it does not restrict | limit especially as said anti-aging agent, For example, conventionally well-known things, such as a phenol type compound, an amine type compound, an organic sulfur type compound, a phosphine type compound, can be used.

  Although it does not restrict | limit especially as said modifier | denaturant, For example, conventionally well-known things, such as glycols, silicones, alcohol, can be used.

  The addition of the surfactant is not particularly limited. For example, when the epoxy resin sheet is cured by contacting the epoxy resin with air to form an epoxy resin sheet, it can be added to smooth the sheet surface. As said surfactant, various surfactants, such as silicone type, an acryl type, a fluorine type, can be used, for example, Among these, a silicone type is preferable.

  In the present invention, examples of the light diffusing agent include inorganic particles such as silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide, acrylic resins, melamine resins, and silicones. Examples thereof include organic particles made of resin and the like, and particles obtained by coating the inorganic particles with the organic resin. Of these, inorganic particles such as silica and alumina, and organic particles such as silicone resin and acrylic resin are preferable.

  The average particle diameter of the light diffusing agent is, for example, preferably in the range of 0.2 μm to 100 μm, more preferably in the range of 1 μm to 80 μm, and particularly preferably in the range of 1 μm to 50 μm because sufficient light diffusibility is obtained. . The method for measuring the average particle diameter of the light diffusing agent is not particularly limited. For example, based on JIS B 9925, a scattering type particle size distribution measuring device (for example, trade name LA-910 (manufactured by Horiba, Ltd.)). It can be measured.

  The light diffusing agent is not particularly limited as long as its refractive index is different from that of the epoxy resin, but as described above, the absolute difference in refractive index between the epoxy resin and the light diffusing agent is not limited. The value is preferably in the range of 0.03 to 0.30, more preferably in the range of 0.03 to 0.20. If the absolute value of the refractive index difference is in the range of 0.03 to 0.30, for example, a sufficient light diffusion function can be provided. The refractive index of the epoxy resin is, for example, a refractive index indicated by a cured layer (no light diffusing agent added) formed by curing the epoxy resin without adding a light diffusing agent, and the light diffusion. A combination in which the absolute value of the difference from the refractive index of the agent is in the range of 0.03 to 0.30 is preferable. The term “cured layer” as used herein is used only for the measurement of the refractive index of an epoxy resin, and does not limit the resin sheet of the present invention, its use, use, or the like.

  Moreover, it is preferable to use the light diffusing agent whose absolute value of the difference in refractive index is within the above range for the terpene type epoxy resin. The refractive index can be set by a conventionally known method.

  In the epoxy resin layer, the content ratio of the light diffusing agent with respect to the total epoxy resin is, for example, in the range of 0.1 to 60% by weight, more preferably 0.5 to 40% by weight, and still more preferably 1 to 30% by weight.

  As a form of the resin sheet of the present invention, for example, as shown below, the first embodiment including a single-layer epoxy resin layer in which the light diffusing agent is unevenly distributed, two epoxy resin layers are integrated. In addition to the resin sheet in the second embodiment and the first or second embodiment in which the light diffusing agent is unevenly distributed, the third embodiment further includes at least one of a hard coat layer or a gas barrier layer. can give. These forms will be described below with reference to FIGS.

(First embodiment)
The resin sheet of this embodiment includes the single-layer epoxy resin layer in which the light diffusing agent is unevenly distributed in the thickness direction. An example of this single-layer epoxy resin layer is shown in the side view of FIG.

  As illustrated, the resin sheet 1 of this embodiment is a single-layer epoxy resin layer including an epoxy resin 102 including a terpene type epoxy resin and a light diffusing agent 101. The light diffusing agent 101 is unevenly distributed in the thickness direction of the epoxy resin layer. That is, in the resin layer, the resin layer is separated into a part containing a large amount of the light diffusing agent 101 (lower side in the figure) and a part containing little or no light diffusing agent (upper side in the figure). Yes.

  Although the thickness of the said resin sheet 1 can be suitably determined according to the use purpose etc., for example, it is preferable that it is 50 micrometers or more. In general, for example, it is preferably 50 μm to 1 mm, more preferably 50 to 900 μm, particularly preferably from the viewpoint of taking advantage of characteristics as a sheet such as rigidity, flexibility, thin and light weight, and the like. Is in the range of 50-800 μm. Moreover, when using the resin sheet 1 for optical uses, such as the above optical cell substrates, it is preferable that it is the range of 200-500 micrometers.

  In the resin sheet composed of such a single-layer epoxy resin layer, for example, it is preferable that the light diffusing agent is unevenly distributed on one surface side as described above. When such a resin sheet is used as a liquid crystal cell substrate, for example, the sheet may be arranged so that the unevenly distributed surface of the light diffusing agent is on the liquid crystal side to be carried. With this arrangement, the light diffusing agent is in a state adjacent to the liquid crystal, and thus, for example, the display quality of the liquid crystal display device becomes clearer and glare can be suppressed.

  The surface on which the light diffusing agent is unevenly distributed is preferably smooth. By smoothing the surface in this way, for example, when used as a liquid crystal cell substrate, it becomes even easier to form an alignment film, a transparent electrode, etc. on the surface. Specifically, the surface roughness (Ra) of the surface is preferably 1 nm or less, for example.

  The unevenly distributed portion of the light diffusing agent in the epoxy resin layer is preferably a region from one surface to 1/50 to 1/2 of the total thickness, and more preferably 1/40 to 1/3. And particularly preferably 1/30 to 1/4.

  Moreover, it is preferable that the ratio of the said light-diffusion agent in the said uneven distribution location is 0.1 to 80 weight%, for example, More preferably, it is 0.5 to 60 weight%. Further, the density of the light diffusing agent in the unevenly distributed portion is preferably 5 times or more, more preferably 10 times or more, and particularly preferably 20 times or more of the ratio of the light diffusing agent in other portions. . Of course, the light diffusing agent does not have to be contained in the part other than the unevenly distributed part.

  Although the manufacturing method in particular of such a resin sheet 1 is not restrict | limited, For example, it can manufacture by the method shown below.

  An epoxy resin containing a terpene type epoxy resin and a light diffusing agent are mixed to prepare an epoxy resin coating solution. Further, it may be prepared by appropriately dispersing in an appropriate solvent. And the said coating liquid is expand | deployed in a sheet form on a board | substrate. For example, by setting various conditions such as the ratio between the epoxy resin and the light diffusing agent, the particle size and weight of the light diffusing agent, the amount of the solvent, etc., until the spread layer is formed into a film by drying or curing In addition, the light diffusing agent can be naturally settled or suspended in the spreading layer. Thus, a resin sheet composed of a single-layer epoxy resin layer in which the light diffusing agent is unevenly distributed in the thickness direction can be formed.

  To settle or float the light diffusing agent, for example, there is a method of setting the specific gravity of the light diffusing agent and the specific gravity of the epoxy resin to different values. Thus, if the specific gravity of both is set to a different value, the light diffusing agent settles or floats based on the specific gravity difference between the two. That is, if the specific gravity of the light diffusing agent is larger than the specific gravity of the epoxy resin, the light diffusing agent settles downward, and the spreading layer is in a state where the light diffusing agent is unevenly distributed below in the thickness direction. The epoxy resin layer 1 is formed by drying. On the other hand, if the specific gravity of the light diffusing agent is smaller than the specific gravity of the epoxy resin, the light diffusing agent floats upward, and the development is performed in a state where the light diffusing agent is unevenly distributed above the thickness direction. The layer dries and the epoxy resin layer 1 is formed.

  When the light diffusing agent or floating is used as described above, the absolute value | A−B | of the difference between the specific gravity (A) of the light diffusing agent and the specific gravity (B) of the epoxy resin is set to, for example, 0. It is set to 3 or more, preferably 0.5 or more, more preferably 0.7 or more.

  The developing method of the coating liquid is not particularly limited, and examples thereof include a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, an extrusion method, a curtain coating method, and a spray coating method. The development layer may be formed by fluid development on the substrate surface.

  The substrate on which the coating liquid is developed is not particularly limited, and examples thereof include a suitable substrate such as stainless steel. As will be described later, when other layers such as a hard coat layer and a gas barrier layer are provided, the coating liquid may be developed using these layers as a substrate.

  The method for drying the spreading layer is not particularly limited, and examples include natural drying, air drying, and heat drying. The drying conditions are not particularly limited as long as the light diffusing agent is sufficiently settled or floated, for example, and is appropriately determined according to the specific gravity difference and the thickness of the epoxy resin layer to be formed. it can.

  Moreover, what is necessary is just to perform hardening processes, such as a heat processing and a light irradiation process, with respect to the said expansion | deployment layer or the epoxy-type resin layer after drying as needed.

Such a single-layer epoxy resin layer may be laminated with another layer, for example. In that case, either one of the outermost layers of the laminate is the epoxy resin layer, the light diffusing agent is unevenly distributed on the outermost surface side of the epoxy resin layer, and the light diffusing agent is unevenly distributed. The surface of is preferably smooth. As described above, when such a resin sheet is used as a liquid crystal cell substrate, for example, if the light diffusing agent is unevenly distributed on the outermost surface, the surface is arranged so as to be on the liquid crystal side to be supported. The light diffusing agent is adjacent to the liquid crystal. This is because, for example, the display quality of the liquid crystal display device becomes clearer and glare can be suppressed. Also, if the surface on which the light diffusing agent is unevenly distributed is smooth, for example, when used as a liquid crystal cell substrate, it becomes easier to form an alignment film, a transparent electrode, etc. on the surface. Yes (second embodiment)
The resin sheet of this embodiment includes a laminate in which two epoxy resin layers containing the epoxy resin are integrated, and the volume ratio of the light diffusing agent in one epoxy resin layer (first layer). And the volume ratio of the light diffusing agent in the other epoxy resin layer (second layer) is different, and as a whole, the light diffusing agent is unevenly distributed in the thickness direction of the laminate. In such a resin sheet, since two layers having different volume ratios of the light diffusing agent are integrated, the light diffusing agent is not unevenly distributed in the epoxy resin layer as in the first embodiment, but is uniformly dispersed. May be.

  The ratio of the light diffusing agent in the two layers may be different from each other. For example, the ratio in the layer having a small amount of the light diffusing agent is preferably 1/5 or less of the ratio in the layer having a large amount of the light diffusing agent. More preferably, it is 1/10 or less, and particularly preferably 1/20 or less. Further, the other layer may be a layer containing no light diffusing agent.

  In the side view of FIG. 2, the epoxy resin layer containing the epoxy resin and the light diffusing agent and the epoxy resin layer containing the epoxy resin and not containing the light diffusing agent are integrated. An example of the resin sheet which is a laminated body is shown.

  As shown in the drawing, the resin sheet 2 of this embodiment includes an epoxy resin layer 201 containing an epoxy resin 102 containing the terpene type epoxy resin and a light diffusing agent 101 (hereinafter referred to as “light diffusing agent-containing layer”). And an epoxy resin layer 202 containing the epoxy resin 102 and not containing the light diffusing agent 101 (hereinafter referred to as “light diffusing agent non-containing layer”). In the resin sheet of the present embodiment, unlike the first embodiment, the light diffusing agent 101 does not have to be unevenly distributed in the light diffusing agent-containing layer 201. In the light diffusing agent-containing layer 201, even if the light diffusing agent 101 is in a uniformly dispersed state, the light dispersing agent 101 is unevenly distributed in the thickness direction of the laminate 2 by further including the light diffusing non-containing layer 202. This is because it becomes a state. That is, in the resin sheet 2, the resin sheet 2 is separated into a part containing a large amount of the light diffusing agent 101 (light dispersing agent-containing layer 201) and a part not containing the light diffusing agent (light dispersing agent non-containing layer 202). It is. In the light diffusing agent-containing layer 201, it is preferable that the light diffusing agent 101 is uniformly dispersed.

  The total thickness of the resin sheet 2 can be appropriately determined according to, for example, the purpose of use, but is preferably 50 μm or more. In general, for example, it is preferably 50 μm to 1 mm, more preferably 50 to 900 μm, particularly preferably from the viewpoint of taking advantage of characteristics as a sheet such as rigidity, flexibility, thin and light weight, and the like. Is in the range of 50-800 μm. Moreover, when using the resin sheet 1 for optical uses, such as the above optical cell substrates, it is preferable that it is the range of 200-500 micrometers.

  When the resin sheet of such a laminate is used as a liquid crystal cell substrate, by placing the light diffusing agent-containing layer 201 side surface on the liquid crystal side, the light diffusing agent is adjacent to the liquid crystal, For example, the display quality of the liquid crystal display device becomes clearer and glare can be suppressed.

  The surface of the resin sheet on the light diffusing agent-containing layer 201 side is preferably smooth. This is because, as described above, when this is used as a liquid crystal cell substrate, for example, formation of an alignment film, a transparent electrode or the like on the surface is further facilitated.

  Although the manufacturing method in particular of such a resin sheet 2 is not restrict | limited, For example, it can manufacture with the method shown below. Unless otherwise indicated, the same processing as in the first embodiment can be performed.

  An epoxy resin containing a terpene type epoxy resin and a light diffusing agent are mixed to prepare a light diffusing agent-containing coating liquid (dispersed in a suitable solvent as necessary), while the epoxy resin is used as the solvent. Disperse to prepare a coating solution containing no light diffusing agent. Then, the light diffusing agent-containing coating solution is spread on a substrate in a sheet shape, and the spread layer is made into a semi-dried or semi-cured state, and then the light diffusing agent-free coating is further formed on the spread layer. Expand the working fluid. Then, both spreading layers may be completely dried or cured. As a result, a resin sheet in which the light diffusing agent non-containing layer 202 is laminated on the light diffusing agent-containing layer 201 can be formed. Thus, after the former spreading | diffusion layer is semi-hardened, by forming the latter spreading | diffusion layer, it can prevent or suppress that a light-diffusion agent mixes in the other spreading | diffusion layer, for example. The development order of the two coating liquids is not particularly limited, and for example, the light diffusing agent-free coating liquid may be developed first. In the present invention, if the uneven distribution of the light diffusing agent is, for example, the volume ratio as described above, both of the two kinds of coating liquids may contain the light diffusing agent.

In this embodiment, since it is not necessary to unevenly distribute the light diffusing agent in the single layer, for example, the sedimentation / floating of the light diffusing agent, such as the specific gravity of the light diffusing agent and the epoxy resin, is not particularly considered. Also good.
(Third embodiment)
The resin sheet of the present embodiment further includes at least one of a hard coat layer and a gas barrier layer, in addition to the resin sheet in the first or second embodiment. FIG. 3 shows a side view of an example of a resin sheet in which a hard coat layer and a gas barrier layer are further laminated on the laminate of the second embodiment.

  As illustrated, the resin sheet 3 of the present embodiment includes the laminate 2 of the light diffusing agent-containing layer 201 and the light diffusing agent-free layer 202 in the second embodiment, the gas barrier layer 304, and the hard coat layer 303. The laminate 2 is laminated on the hard coat layer 303 via the gas barrier layer 304, and the light diffusing agent-free layer 202 of the laminate 2 faces the gas barrier layer 304.

  If the hard coat layer 303 is formed as the outermost layer of the resin sheet as described above, the scratch resistance and the like of the resin sheet can be further improved. In addition, in a liquid crystal display device, for example, when moisture or oxygen penetrates the liquid crystal cell substrate and enters the cell, there is a risk of deterioration of the liquid crystal, appearance of bubbles due to formation of bubbles, disconnection of the transparent conductive film pattern, or the like. However, as described above, if a gas barrier layer is provided between the epoxy resin layer and the hard coat layer, the permeation of moisture and gas is further prevented.

  The resin sheet 3 may have only one of a hard coat layer and a gas barrier layer, but has both chemical resistance, scratch resistance and moisture resistance, and becomes a high-performance resin sheet. It is preferable to have. When both the hard coat layer and the gas barrier layer are included, the stacking order is not particularly limited. However, as shown in FIG. 3, it is preferable to stack the epoxy resin layer, the gas barrier layer, and the hard coat layer in this order. In particular, the hard coat layer is preferably laminated as the outermost layer because it is excellent in impact resistance and chemical resistance. Further, a hard coat layer may be further laminated on the light diffusing agent-containing layer 201 side of the laminate 2.

  The material for forming the hard coat layer is not particularly limited, and examples thereof include urethane resins, acrylic resins, and polyester resins. Also, for example, polyarylate resins, sulfone resins, amide resins, imide resins, polyethersulfone resins, polyetherimide resins, polycarbonate resins, silicone resins, fluorine resins, polyolefin resins, styrene Resin, vinyl pyrrolidone resin, cellulose resin, acrylonitrile resin and the like can also be used. Among these, urethane resin is preferable, and urethane acrylate is more preferable. These resins may be one kind or a blend resin in which two or more kinds are mixed.

  In addition to the forming material, the hard coat layer contains transparent particles for the purpose of providing an antiglare function for preventing a so-called ghost phenomenon in which an external environment such as illumination light or a keyboard is reflected on the screen. May be. Examples of the material for the transparent particles include inorganic materials such as glass and silica, acrylic resins, polyester resins, epoxy resins, melanin resins, urethane resins, polycarbonate resins, polystyrene resins, silicone resins, benzoguanamines. , Organic materials such as melanin / benzoguanamine condensate, benzoguanamine / formaldehyde condensate, etc., and the average particle size thereof is, for example, in the range of 0.5 to 30 μm, preferably 1 to 25 μm, more preferably 5 to 20 μm. Moreover, since the volume ratio with respect to the said hard-coat layer of the said transparent particle can provide favorable anti-glare property, it is preferable that it is 1-50 volume%. The volume ratio can be calculated from [volume of transparent particles / volume of hard coat layer].

  The thickness of the hard coat layer is not particularly limited, but is usually in the range of, for example, 1 to 10 μm, preferably 1.5 from the viewpoint of preventing the occurrence of peeling during production and cracking during peeling. It is the range of -8 micrometers, More preferably, it is the range of 2-5 micrometers.

  Examples of the gas barrier layer include an organic gas barrier layer and an inorganic gas barrier layer. The material for forming the organic gas barrier layer is not particularly limited, but, for example, polyvinyl alcohol and its partially saponified products, vinyl alcohol polymers such as ethylene-vinyl alcohol copolymer, and oxygen permeation such as polyacrylonitrile and polyvinylidene chloride. Small materials can be used, and among these, vinyl alcohol polymers are particularly preferable from the viewpoint of high gas barrier properties.

  The thickness of the organic gas barrier layer is, for example, preferably 15 μm or less from the viewpoint of transparency, coloration prevention, functionality such as gas barrier properties, thinness, flexibility of the obtained resin sheet, and the like. It is 13 micrometers or less, More preferably, it is 2-10 micrometers, Most preferably, it is the range of 3-5 micrometers. If the thickness is 15 μm or less, the resin sheet can maintain a lower yellowness index (YI value), and if it is 2 μm or more, a sufficient gas barrier function is maintained.

  On the other hand, as a material for forming the inorganic gas barrier layer, for example, transparent materials such as silicon oxide, magnesium oxide, aluminum oxide, and zinc oxide can be used. Among these, for example, gas barrier properties and adhesion to the base material layer can be used. From the viewpoint of excellent properties, silicon oxide and silicon nitride are preferable.

  As said silicon oxide, it is preferable that the ratio of the number of oxygen atoms with respect to the number of silicon atoms is 1.5-2.0, for example. This is because, at such a ratio, for example, the inorganic gas barrier layer is further excellent in terms of gas barrier properties, transparency, surface flatness, flexibility, film stress, cost, and the like. In the silicon oxide, the maximum value of the ratio of the number of oxygen atoms to the number of silicon atoms is 2.0.

  As the silicon nitride, for example, the ratio of the number of nitrogen atoms to the number of silicon atoms is preferably 1.0 to 4/3.

  The thickness of the inorganic gas barrier layer is not particularly limited, but is preferably in the range of 5 to 200 nm, for example. If the thickness is 5 nm or more, for example, more excellent gas barrier properties can be obtained, and if the thickness is 200 nm or less, the transparency, flexibility, film stress, and cost are also excellent.

  The method for forming such a resin sheet is not particularly limited. For example, after forming a hard coat layer on the base material as described above, a gas barrier layer is formed thereon, and an epoxy resin layer is further formed. do it.

  The formation method in particular of the said hard-coat layer and a gas barrier layer is not restrict | limited, A conventionally well-known method is employable. For example, the forming material may be mixed with the solvent to prepare a coating solution, which may be applied on a substrate by the above-described coating method and dried. Moreover, you may perform hardening processes, such as heat processing and a light irradiation process, as needed.

  In the case of a resin sheet including a gas barrier layer, for example, the hard coat layer may be formed on a substrate, the gas barrier layer may be formed thereon, and then the epoxy resin layer may be further formed. The method for forming the gas barrier layer is not particularly limited, and for example, a conventionally known method can be appropriately employed.

  The resin sheet of the present invention as described above has a glass transition temperature (Tg) of, for example, 170 ° C. or higher, preferably 180 ° C. or higher, more preferably 200 ° C. or higher. Moreover, it is preferable that the glass transition temperature (Tg) of the said epoxy-type resin layer is also the same range, and if it is 170 degreeC or more, for example, the lamination | stacking of an inorganic gas barrier layer, etc. can prevent warping and a deformation | transformation further.

  The light transmittance is, for example, 88% or more, preferably 89% or more, more preferably 90% or more, still more preferably 91% or more, and particularly preferably close to 100% or 100%. When the light transmittance is 88% or more, when an image display device such as a liquid crystal display device is assembled using this resin sheet, the display becomes sufficiently bright and the display quality is further improved.

  The light transmittance can be obtained, for example, by measuring the transmittance at λ = 550 nm using a high-speed spectrophotometer.

  For example, the resin sheet of the present invention has a breaking strength of 45 N or more, preferably 60 N or more, more preferably 70 N or more, and particularly preferably 80 N or more.

  The breaking strength refers to a scratch having a depth of about 0.3 μm on the back side of the resin sheet, a solid surface flat plate on the back side of the resin sheet, and a flat plate having a hole with a diameter of 20 mm on the front side. After the laminated body is arranged horizontally and the four corners are fixed, a load is applied by a stainless steel ball having a diameter of 10 mm to the center of the exposed portion of the resin sheet in the hole from the vertical direction of the flat plate having the hole. Is the force when the resin sheet breaks.

  The method for measuring the breaking strength will be specifically described with reference to FIG. (A) is a perspective view showing an example of a breaking strength measuring device, (B) is a cross-sectional view in the II direction of (A), and parts other than the cut surface are shown in FIG. Omitted. First, the resin sheet 11 is cut into a size of about 30 mm × 30 mm, and a scratch having a depth of about 0.3 μm is made on the back surface thereof. Specifically, as shown in the plan view of FIG. 5 showing the inside of the hole 14, at least a range of 15 mm × 15 mm in the center of the exposed portion of the resin sheet 11 in the hole 14 (11 a in FIG. 5: inside the dotted line) What is necessary is just to scratch the back of the. Such a scratch having a depth of about 0.3 μm can be formed, for example, by rubbing the back surface with a paper having a particle size of # 2000. In measuring the breaking strength, the depth of the scratches made on the back surface of the resin sheet in advance is confirmed by a conventionally known method using, for example, a surface roughness meter.

  And the resin sheet 1 is laminated | stacked on the surface solid flat plate 2, and the flat plate 13 which has the hole 14 is laminated | stacked on it so that the back surface which gave this damage | wound may contact. And this laminated body is installed horizontally and the four corners are fixed with the stoppers 15. The hole 14 has a diameter of 20 mm, and the hole 14 is provided substantially at the center of the flat plate 14. Next, from the vertical direction of the laminate (arrow A in FIG. 4), a stainless steel ball 16 having a diameter of 10 mm provided at the tip of the rod 17 is provided at the center of the resin sheet 11 exposed inside the hole 14. A pressing load is applied at a speed of 100 mm / min. And what is necessary is just to let the force at the time of the said resin sheet 11 fracture | rupture be fracture strength. This measuring method is used only for the measurement of the breaking strength, and does not limit the resin sheet of the present invention, its use, use, or the like.

  The size of the solid surface flat plate or the flat plate having holes is not particularly limited, and is, for example, in the range of 50 mm × 50 mm to 200 mm × 200 mm, and the thickness is not particularly limited, but is, for example, about 5 mm to 30 mm. It is preferable.

  The resin sheet of this invention can be used for various uses, for example, can also be used preferably as a substrate for image displays, such as a liquid crystal cell substrate and a substrate for EL displays, and a substrate for solar cells. When used as various substrates in this way, for example, it may be used in the same manner as a conventionally used transparent substrate such as a glass substrate.

  The liquid crystal cell substrate of the present invention can be used for a liquid crystal display device, the EL display substrate of the present invention can be used for an EL display device, and the solar cell substrate of the present invention can be used for a solar cell substrate. These various substrates can be used, for example, as substitutes for glass substrates used in various conventional display devices and solar cells. If such various substrates of the present invention are used, for example, a sufficient strength can be maintained, and a reduction in thickness and weight can be realized.

  A liquid crystal display device generally includes a liquid crystal cell in which liquid crystal is held on a liquid crystal cell substrate having electrodes, a polarizing plate, a reflector, and a backlight, and is configured by incorporating a drive circuit and the like. In the liquid crystal display device of the present invention, the resin sheet of the present invention may be used as a liquid crystal cell substrate, and there is no particular limitation except for this point, and various conventionally known components may be provided. Therefore, in the liquid crystal display device of the present invention, the liquid crystal cell substrate of the present invention is further provided with, for example, a light diffusing plate, an antiglare layer, an antireflection film, a protective layer, a protective plate provided on the polarizing plate on the viewing side, Or you may combine optical components, such as a phase difference plate for compensation provided between a liquid crystal cell and the polarization | polarized-light side of a visual recognition side, and a board.

  An EL display device is generally configured by sequentially laminating a transparent electrode, an organic light emitting layer including a light emitter (organic EL light emitter), and a metal electrode on a transparent substrate (EL display substrate). Yes. In the EL display device of the present invention, the resin sheet of the present invention may be used as an EL display substrate. Except for this point, there is no particular limitation, and various conventionally known components may be provided.

  The organic light emitting layer is a laminate of organic thin films containing various light emitters. Examples of such a laminate include a laminate of a hole injection layer containing a triphenylamine derivative and a light emitting layer made of a fluorescent organic solid such as anthracene, a light emitting layer and a perylene derivative as described above, and the like. Various combinations are known, such as a laminate with an electron injection layer containing, a laminate with a hole injection layer, a light emitting layer, and an electron injection layer as described above.

  In organic EL display devices, holes and electrons are usually injected into an organic light emitting layer by applying a voltage to a transparent electrode and a metal electrode, and the energy generated by recombination of these holes and electrons is a fluorescent substance. The phosphor emits light based on the principle that it emits light when the excited phosphor returns to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be expected from this, the current and the light emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

  In an organic EL display device, in order to extract light emitted from the organic light emitting layer, at least one of the electrodes needs to be transparent, and is usually a transparent electrode formed of a transparent conductor such as indium tin oxide (ITO). Is used as the anode. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are used.

  In the organic EL display device having such a configuration, the organic light emitting layer is preferably formed of an extremely thin film having a thickness of about 10 nm, for example. With such a thin thickness, for example, the organic light emitting layer can transmit light almost completely, like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate when not emitting light, passes through the transparent electrode and the organic light-emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. In addition, the display surface of the organic EL display device looks like a mirror surface.

  For example, in the case where the EL device of the present invention is an organic EL device provided with a transparent electrode on the surface side of the organic light emitting layer that emits light by applying a voltage and provided with a metal electrode on the back surface side of the organic light emitting layer, the surface of the transparent electrode It is preferable to provide a polarizing plate on the side and a phase plate between the transparent electrode and the polarizing plate.

  Since the phase plate and the polarizing plate have an action of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, if a quarter-wave plate is used as the phase plate and the angle between the polarization directions of the polarizing plate and the phase plate is adjusted to π / 4, the mirror surface of the metal electrode can be completely shielded. . That is, external light incident on the organic EL device can transmit only the linearly polarized light component by the polarizing plate. This linearly polarized light is generally elliptically polarized light depending on the phase plate, but is particularly circularly polarized when the phase plate is a quarter wave plate and the angle between the polarization directions of the polarizing plate and the phase plate is π / 4. For example, the circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light again by the phase plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot permeate | transmit a polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “parts” means “parts by weight”.

(Example 1)
A present Example is an example of the resin sheet containing the single layer epoxy-type resin layer in which the light-diffusion agent is unevenly distributed.

  A terpene novolak type epoxy resin (epoxy equivalent 253) represented by the above formula (1) as a terpene type epoxy resin and 3,4-epoxycyclohexylmethyl represented by the following formula (2) as another epoxy resin (alicyclic) -3,4-epoxycyclohexanecarboxylate (specific gravity about 1.2), methylhexahydrophthalic anhydride represented by the following formula (3) as a curing agent, and tetra represented by the following formula (4) as a curing catalyst. -N-Butylphosphonium o, o-diethyl phosphorodithioate was used, respectively, and these were stirred and mixed so that it might become the following composition, and the epoxy resin liquid was prepared. The epoxy resin represented by the formula (1) has an average value of n of 1.3. An alumina-containing epoxy resin liquid was prepared by stirring and mixing 100 parts of this epoxy resin liquid with 0.8 parts of alumina particles having a specific gravity of about 3.9 and an average particle diameter of 5 μm as a light diffusing agent. The refractive index of the alumina particles was 1.77. On the other hand, a urethane acrylate represented by the following formula (5) is suspended in toluene to prepare a 17% by weight urethane acrylate solution, and polyvinyl alcohol (PVA) (degree of polymerization: 1800) is suspended in water. A 5 wt% PVA aqueous solution was prepared.

組成 重量部
・ テルペン型エポキシ樹脂 ２６．６
・ 3,4-エホ゜キシシクロヘキシルメチル-3,4-
エホ゜キシシクロヘキサンカルボキシレート ２６．６
・ メチルヘキサヒドロフタル酸無水物 ４８．５
・ テトラ-n-フ゛チルホスホニウム o,o-
シ゛エチルホスホロシ゛チオエート １．０
そして、図６に例示した装置を用いて、流延法に従い、エポキシ系樹脂層とガスバリア層とハードコート層との積層体である樹脂シートを作製した。同図に示す製造装置は、駆動ドラム（２２）、従動ドラム（２３）、前記両ドラムを介して矢印方向に一定速度で走行するステンレス製エンドレスベルト（２１）、ハードコート層塗布用ダイ（２４）、ガスバリア層塗布用ダイ（２５）、エポキシ樹脂塗布用ダイ（２６）、ＵＶ硬化装置（２８）、乾燥機（２９）、（３０）を備える。

Composition parts by weight
・ Terpene type epoxy resin 26.6
・ 3,4-Epoxycyclohexylmethyl-3,4-
Ethoxycyclohexanecarboxylate 26.6
・ Methylhexahydrophthalic anhydride 48.5
・ Tetra-n-butylphosphonium o, o-
Diethyl phosphorothioate 1.0
And the resin sheet which is a laminated body of an epoxy resin layer, a gas barrier layer, and a hard-coat layer was produced according to the casting method using the apparatus illustrated in FIG. The manufacturing apparatus shown in the figure includes a driving drum (22), a driven drum (23), a stainless steel endless belt (21) that travels at a constant speed in the direction of the arrow through the two drums, and a hard coat layer coating die (24). ), Gas barrier layer coating die (25), epoxy resin coating die (26), UV curing device (28), dryers (29), (30).

  First, the urethane acrylate solution was cast and applied from the die (24) to the surface of the endless belt (21) at a running speed of 0.3 m / min, air-dried to volatilize toluene, and then the UV curable apparatus (28 ) To form a hard coat layer (33) having a thickness of 2.0 μm. Subsequently, the aqueous PVA solution was cast and applied from the die (25) onto the hard coat layer (34) at a running speed of 0.3 m / min, and dried at 100 ° C. for 10 minutes using a dryer (29). A 3.7 μm gas barrier layer (34) was formed. Further, the alumina-containing epoxy resin liquid is cast-applied from the die (26) onto the gas barrier layer (34) at a running speed of 0.3 m / min, and cured at 200 ° C. for 60 minutes using the dryer (30). Thus, an epoxy resin layer (39) having a film thickness of 400 μm was formed. The alumina in the epoxy resin liquid starts to settle immediately after coating, and most of the distribution is unevenly distributed in the 50 μm-thick layer from the lower gas barrier layer (34) side. And separated into a light diffusing agent-containing side (35) and a light diffusing agent-free side (36). Thus, a laminate (40) was obtained in which the epoxy resin layer (39) was laminated on the hard coat layer (33) via the gas barrier layer (34). The refractive index of the epoxy resin layer without addition of light diffusing agent, which was formed in the same manner except that alumina as a light diffusing agent was not added, was 1.52.

  Next, the laminate (40) was peeled off from the endless belt and left on a glass plate at 180 ° C. for 0.5 hours in an atmosphere in which the oxygen concentration was changed to 0.5% by nitrogen substitution, and after-curing was performed. The laminated body thus obtained was used as a resin sheet (Example 1).

(Example 2)
A present Example is an example of the resin sheet containing the laminated body of the epoxy resin layer containing a light-diffusion agent, and the epoxy resin layer which does not contain the said light-diffusion agent.

  In the same manner as in Example 1, an alumina-containing epoxy resin solution, a urethane acrylate solution, and a PVA aqueous solution were prepared. Furthermore, an alumina-free epoxy resin solution was prepared in the same manner as in Example 1 except that alumina was not mixed.

  And the resin sheet which is a laminated body of an epoxy resin layer and a hard-coat layer was produced according to the casting method using the apparatus illustrated in FIG. The manufacturing apparatus shown in the figure includes a driving drum (22), a driven drum (23), a stainless steel endless belt (21) that travels at a constant speed in the direction of the arrow through the two drums, and a hard coat layer coating die (24). ), An alumina-containing epoxy resin coating die (26), an alumina-free epoxy resin layer coating die (27), a UV curing device (28), and dryers (31) and (32).

  First, in the same manner as in Example 1, a hard coat layer (33) was formed on the endless belt (21). Then, an alumina-free epoxy resin liquid is cast on the hard coat layer (33) from the die (27) at a running speed of 0.3 m / min, and treated at 120 ° C. for 30 minutes by the dryer (31). After forming a semi-cured state by forming an alumina-free layer (38), a light diffusing agent-containing epoxy resin liquid is cast and applied from the die (26) at a rate of 0.3 m / min. Layer (37) was formed. The light diffusing agent-free layer (38) and the light diffusing agent-containing layer (37) are completely cured by treating them at 200 ° C. for 60 minutes with the dryer (32), and the light diffusing agent is unevenly distributed. A body epoxy resin layer (39) was obtained. The light diffusing agent-free layer (38) had a thickness of 350 μm, and the light diffusing agent-containing layer (37) had a thickness of 50 μm. Thus, a laminate (41) was obtained in which the light diffusing agent-free layer (38) and the light diffusing agent-containing layer (37) were laminated on the hard coat layer (33).

  Next, the laminate (41) was peeled off from the endless belt and left on a glass plate at 180 ° C. for 1 hour in an atmosphere in which the oxygen concentration was changed to 0.5% by nitrogen substitution to perform after-cure. The laminate thus obtained was used as a resin sheet (Example 2).

(Comparative Example 1)
A resin sheet was produced in the same manner as in Example 1 except that the epoxy resin solution did not contain alumina.

(Comparative Example 2)
The terpene type epoxy resin represented by the formula (1) was replaced with 26.6 parts by weight, except that 26.6 parts by weight of the epoxy resin represented by the formula (2) was used (total 53.2 parts by weight). In the same manner as in Example 1, a resin sheet was produced.

  For the resin sheets obtained in Examples 1 and 2 and Comparative Example 1, various physical properties were evaluated by the following methods. These results are shown in Table 1 below.

1. Glass transition temperature (℃)
About each said resin sheet, a viscoelastic spectrum was measured using the viscoelastic spectrometer (brand name Ares; product made from a rheometric scientific company), and the peak value of tan-delta was made into the glass transition temperature (Tg).

2. Light transmittance (%)
About each said resin sheet, the transmittance | permeability of (lambda) = 550nm was measured using the high-speed spectrophotometer (brand name DOT-3C; Murakami Color Research Laboratory make).

3. Breaking strength (N)
About each said resin sheet, the force at the time of the fracture | rupture of a resin sheet was measured by the measuring method illustrated in FIG. 4 as mentioned above using the autograph (made by Shimadzu Corporation). The thickness of the solid surface flat plate 2 and the flat plate 3 having a hole with a diameter of 20 mm were 30 mm, and the material was stainless steel. Further, the back surface of the resin sheet 30 (the back surface of the hard coat layer 32) was scratched with paper having a particle size of # 2000. And when the depth of the flaw was measured at random by 5 points with a roughness meter (trade name P-11: manufactured by Tencor), each point was 0.3 μm, and any resin sheet was Similar results were obtained.

4). Yellowness index: YI value The yellowness index of each resin sheet was measured according to JIS standard K-7103 using a high-speed spectrophotometer device (trade name: CMS-500: manufactured by Murakami Color Research Laboratory). The size of the resin sheet sample was 30 × 50 mm.

5. Display quality A liquid crystal display device was assembled by a conventionally known method except that each resin sheet was used as a liquid crystal cell substrate. Then, each of the manufactured liquid crystal display devices is placed in a dark room, and the liquid crystal display device is irradiated with light from a ring illumination device so as to have an angle of 20 ° with respect to the normal line of the display screen in the liquid crystal display device. The display quality of black display in the voltage application state of was examined. In addition, the display quality of white display in the state where no voltage was applied was also examined. And about these display quality, it evaluated based on the following reference | standard.

  ○: Glare was suppressed in white display.

X: Glare was seen in white display.
(Table 1)
Tg Light transmittance Intensity Yellowness index Display quality
(℃) (%) (N)
Example 1 213 88 89 0.9 ○
Example 2 212 89 90 0.6
Comparative Example 1 213 91 90 0.9 ×
Comparative Example 2 226 88 25 0.9 ○
As shown in Table 1, according to Examples 1 and 2, the resin sheet is extremely excellent in strength as compared with Comparative Example 2, and when this is used as a liquid crystal cell substrate, a liquid crystal display device excellent in display quality. Was found to be obtained. Moreover, since the resin sheet of the comparative example 1 did not contain a light diffusing agent, glare was seen and there was a problem in display quality.

  As described above, according to the resin sheet of the present invention, since it contains a terpene type epoxy resin, it can be reduced in thickness and weight, and exhibits high light transmittance and excellent strength. Further, since the light diffusing agent is unevenly distributed in the thickness direction, for example, when used as a liquid crystal cell substrate of a liquid crystal display device, glare caused by external light such as illumination light or a backlight built in the liquid crystal display device. Can be prevented. When used as the liquid crystal cell substrate, the resin sheet itself is provided with a light diffusing function. For example, it is not necessary to separately provide a light diffusing sheet or the like, and the liquid crystal cell can be made thinner and lighter. Become. Further, since the light diffusing agent is unevenly distributed, the liquid crystal display device can be configured such that the light diffusing agent is disposed only near the liquid crystal, so that the clearness of the display can be further improved.

It is a side view which shows one Embodiment of the resin sheet of this invention. It is a side view which shows other embodiment of the resin sheet of this invention. It is a side view which shows other embodiment of the resin sheet of this invention. It is a schematic diagram of the intensity | strength measuring apparatus used in this invention, Comprising: (A) is the perspective view, (B) is a fragmentary sectional view. It is a partial top view of the resin sheet of this invention when using for the said intensity | strength measuring apparatus. It is a side view which shows the manufacturing process of the resin sheet in one Example of this invention. It is a side view which shows the manufacturing process of the resin sheet in another Example in this invention.

Explanation of symbols

1, 2, 3, 11, 40, 41: Resin sheet 101: Light diffusing agent 102: Epoxy resin 201: Light diffusing agent-containing layer 202: Light diffusing agent non-containing layer 33, 303: Hard coat layer 34, 304: Gas barrier layer 12: Solid surface flat plate 13: Flat plate 14: Hole 15: Stopper 16: Stainless steel ball 17: Support rod 21: Endless belt 22: Drive drum 23: Drive drum 24, 25, 26, 27: Die 28: UV curing Apparatus 29-32: Dryer 35: Light diffusing agent containing side 36: Light diffusing agent non-containing side 37: Light diffusing agent containing layer 38: Light diffusing agent non-containing layer 39: Epoxy resin layer in which light diffusing agent is unevenly distributed

Claims (24)

A particle-dispersed resin sheet comprising an epoxy resin and a particulate light diffusing agent, wherein the light diffusing agent is dispersed,
The epoxy resin includes an epoxy resin having a terpene skeleton,
The refractive index of the light diffusing agent is different from the refractive index of the epoxy resin,
The particle-dispersed resin sheet, wherein the light diffusing agent is unevenly distributed in the thickness direction of the sheet. The resin sheet according to claim 1, wherein the epoxy resin having a terpene skeleton has a structure represented by the following formula (1).

In the above formula, n is the degree of polymerization and is an integer of 0-5. The particle-dispersed resin sheet according to claim 1 or 2, wherein the epoxy resin further contains an alicyclic epoxy resin. The content rate of the epoxy resin which has the said terpene type frame | skeleton is the range of 9-60 weight% with respect to all the epoxy resins, The particle-dispersed resin sheet as described in any one of Claims 1-3. The particle-dispersed resin sheet according to any one of claims 1 to 4, wherein a light diffusing agent is unevenly distributed on any one surface side of the resin sheet. The particle-dispersed resin sheet according to any one of claims 1 to 5, wherein the unevenly distributed portion of the light diffusing agent in the resin sheet is a region from one surface to 1/50 to 1/2 of the total thickness. The particle-dispersed resin sheet according to claim 5 or 6, wherein a ratio of the light diffusing agent in the unevenly distributed portion of the light diffusing agent is 0.1 to 80% by weight. The particle-dispersed resin sheet according to any one of claims 1 to 7, wherein the resin sheet comprises a single-layer epoxy resin layer in which the light diffusing agent is unevenly distributed. The particle-dispersed resin sheet according to claim 8, wherein the light diffusing agent is unevenly distributed on any one surface side of the epoxy resin layer, and the surface on which the light diffusing agent is unevenly distributed is smooth. The resin sheet is a laminate including a single-layer epoxy resin layer in which a light diffusing agent is unevenly distributed, and one of the outermost layers of the laminate is the epoxy resin layer, and the epoxy resin layer The particle-dispersed resin sheet according to claim 8, wherein the light diffusing agent is unevenly distributed on the outermost surface side, and the surface on which the light diffusing agent is unevenly distributed is smooth. The resin sheet includes a laminate in which two epoxy resin layers containing the epoxy resin are integrated, and the volume ratio of the light diffusing agent in one epoxy resin layer and the light in the other epoxy resin layer. The particle-dispersed resin sheet according to any one of claims 1 to 7, wherein the light diffusing agent is unevenly distributed in a thickness direction of the laminate, which is different from a volume ratio of the diffusing agent. The particle-dispersed resin sheet according to claim 11, wherein the light diffusing agent is uniformly dispersed in the epoxy resin layer. The particle-dispersed resin sheet according to any one of claims 1 to 12, wherein the content ratio of the light diffusing agent to the epoxy resin is in the range of 0.1 to 60% by weight. The particle-dispersed resin sheet according to any one of claims 1 to 13, wherein the average particle diameter of the light diffusing agent is in the range of 0.2 to 100 µm. The light diffusing agent is at least one particle selected from the group consisting of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like. Particle dispersion resin sheet. The particle dispersion system according to any one of claims 1 to 15, wherein an absolute value of a difference between a refractive index of the epoxy resin and a refractive index of the light diffusing agent is in a range of 0.03 to 0.30. Resin sheet. Furthermore, the particle-dispersed resin sheet as described in any one of Claims 1-16 containing a hard-coat layer. The particle-dispersed resin sheet according to any one of claims 1 to 17, further comprising a gas barrier layer. Glass dispersion temperature (Tg) is 170 degreeC or more, The particle-dispersed resin sheet as described in any one of Claims 1-18. The particle-dispersed resin sheet according to any one of claims 1 to 19, wherein the light transmittance is 88% or more. Breaking strength is 45N or more, The particle-dispersed resin sheet as described in any one of Claims 1-20. A substrate for an image display device, comprising the particle-dispersed resin sheet according to any one of claims 1 to 21. An image display device comprising the image display device substrate according to claim 22. The board | substrate for solar cells containing the particle-dispersed resin sheet as described in any one of Claims 1-21.

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