JP2005037737A - Particle dispersed resin sheet, substrate for image display device, and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin sheet, which has excellent heat resistance and mechanical strength, has high light transmittance, and has a light diffusion function. <P>SOLUTION: The particle dispersed resin sheet comprises an epoxy resin 102 having a terpene skeleton and a light diffusion agent 101 having a refractive index different from that of the epoxy resin, wherein the light diffusion agent is uniformly dispersed. Such a resin sheet can be used, for example, for a substrate for an image display device such as a liquid crystal cell substrate and a substrate for a solar cell and, furthermore, can provide image display devices such as a liquid crystal display device and an EL display device. <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 built in a display device.

In order to achieve the above object, the resin sheet of the present invention is a particle-dispersed resin sheet containing an epoxy resin and a particulate light diffusing agent,
The epoxy resin includes an epoxy resin having a terpene skeleton (hereinafter referred to as “terpene 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 uniformly dispersed in the sheet.

  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.

  Further, by using such a resin sheet of the present invention, for example, a substrate for an image display device of the present invention such as a liquid crystal cell substrate or a substrate for an EL device, or a substrate for a solar cell can be provided. By using various image display device substrates, for example, the image display device of the present invention, such as a liquid crystal display device or an EL display device, and a solar cell 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,
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 uniformly dispersed in the sheet.

  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 another epoxy resin 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, tri Nitrogen-containing ring type such as glycidyl 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, An ether ester type or a modified version 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 14-30% 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 resin sheet of the present invention, the content ratio of the light diffusing agent 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 with respect to the total epoxy resin. Is 1 to 30% by weight.

  The resin sheet of the present invention may be a single-layer epoxy resin layer containing the epoxy resin and a light diffusing agent, or may be a laminate including the epoxy resin layer as described later. Good.

  An example of the resin sheet which consists of a single-layer epoxy resin layer is shown in the side view of FIG. As shown in the figure, the resin sheet 1 is composed of a single epoxy resin layer including an epoxy resin 102 and a light diffusing agent 101, and the light diffusing agent 101 is uniformly dispersed in the epoxy resin layer. .

  The thickness of the epoxy resin layer is not particularly limited and can be appropriately determined depending on the application, but is, for example, 50 μm or more, preferably 50 μm to 1 mm from the viewpoint of characteristics such as rigidity, flexibility, thinness and lightness. More preferably, it is the range of 50-900 micrometers, Most preferably, it is the range of 50-800 micrometers. Moreover, especially when using for optical uses, such as a liquid crystal cell board | substrate, the range of 50-800 micrometers is preferable, More preferably, it is the range of 200-500 micrometers.

  The surface of the epoxy resin layer 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.

  Although the manufacturing method in particular of such a resin sheet 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, or if necessary, these are dispersed in an appropriate solvent to prepare an epoxy resin coating solution. Then, this may be developed into a sheet on a substrate, and the developed layer may be formed into a film by drying or curing. As described above, an epoxy resin coating liquid in which a light diffusing agent is dispersed can be prepared, for example, by mixing the epoxy resin and the light diffusing agent without using a solvent.

  The solvent for dispersing the light diffusing agent and the like is not particularly limited, and examples thereof include toluene, xylene, acetone, methyl ethyl ketone, and methyl isobutyl ketone.

  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.

  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. The curing conditions of the epoxy resin containing the terpene type epoxy resin are not particularly limited, but for example, it is preferably cured at 100 to 200 ° C. for 1 to 2 hours. Further, the curing temperature may be raised stepwise, for example, after curing at 150 ° C. for 1 hour, it may be subsequently cured at 200 ° C. for 1 hour.

  Further, as described above, the resin sheet of the present invention may be a laminate including the epoxy resin layer. An example of such a laminate resin sheet is shown in the side view of FIG. As illustrated, the resin sheet 2 includes an epoxy resin layer 1, a gas barrier layer 201, and a hard cover layer 202, and the epoxy resin layer 1 is laminated on the hard cover layer 202 via the gas barrier layer 201. The epoxy resin layer 1 is the same as in FIG. 1 and includes an epoxy resin 102 and a light diffusing agent 101, and the light diffusing agent 101 is uniformly dispersed in the layer.

  When the hard coat layer 202 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 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 has both because it becomes a high-performance resin sheet. It is preferable. 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. 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 other surface side of the epoxy resin layer 1.

  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 190 ° C. or higher, particularly preferably 200 ° C. or higher. is there. 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.

  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. 4 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 (11a in FIG. 4: 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 12, 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 13. Next, from the vertical direction of the laminate (arrow A in FIG. 3), 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.

  In the case where the EL display device of the present invention is an organic EL display device provided with a transparent electrode on the front surface side of the organic light emitting layer that emits light by voltage application and a metal electrode on the back surface side of the organic light emitting layer, for example, It is preferable that a polarizing plate is provided on the surface side and a phase plate is provided 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 display 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”.
(Examples 1-7, Comparative Example 1)
The terpene novolak type epoxy resin (epoxy equivalent 253) represented by the above formula (1) as the terpene type epoxy resin, and the 3,4-epoxycyclohexyl represented by the following formula (2) as another epoxy resin (alicyclic) Methyl-3,4-epoxycyclohexanecarboxylate as a curing agent, methylhexahydrophthalic anhydride represented by the following formula (3) as a curing agent, and tetra-n-butylphosphonium o represented by the following formula (4) as a curing catalyst , O-diethyl phosphorodithioate was used, and these were stirred and mixed so as to have the composition shown in Table 1 to prepare an epoxy resin solution. The epoxy resin represented by the formula (1) has an average value of n of 1.3. To this 840 parts of the epoxy resin liquid, 8.4 parts of silica particles having an average particle diameter of 12 nm were further added as a light diffusing agent, and mixed by stirring to prepare a light diffusing agent-containing epoxy resin liquid. The silica particles have a refractive index of 1.46 and a specific gravity of 2.2. 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.

（表１）
Ａ（重量部） Ｂ（重量部） Ｃ（重量部） Ｄ（重量部） 屈折率
実施例１ ２６．６ ２６．６ ４８．５ １．０ １．５１
実施例２ １４．９ ３４．７ ５３．０ １．０ １．５０
実施例３ ４０．０ １７．２ ４４．９ １．０ １．５１
実施例４ ９．６ ３８．４ ５４．７ １．０ １．４９
実施例５ ３．３ ４３．３ ５６．２ １．０ １．４９
実施例６ ５６．２ ６．３ ３９．１ １．０ １．５２
実施例７ ６３．３ １．３ ３６．９ １．０ １．５２
実施例８ ２６．６ ２６．６ ４８．５ １．０ １．５１
実施例９ ２６．６ ２６．６ ４８．５ １．０ １．５１
比較例１ ０ ４５．１ ５３．９ １．０ １．４９
Ａ：テルペン型エポキシ樹脂
Ｂ：３，４−エポキシシクロヘキシルメチル−３，４−エポキシシクロヘキサンカルボキシレート
Ｃ：メチルヘキサヒドロフタル酸無水物
Ｄ：テトラ−ｎ−ブチルホスホニウムｏ，ｏ−ジエチルホスホロジチオエート
屈折率：光拡散剤無添加エポキシ樹脂層の屈折率

そして、図５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、前記図２に示す樹脂シートを作製した。図５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。

(Table 1)
A (parts by weight) B (parts by weight) C (parts by weight) D (parts by weight) Refractive index
Example 1 26.6 26.6 48.5 1.0 1.51
Example 2 14.9 34.7 53.0 1.0 1.50
Example 3 40.0 17.2 44.9 1.0 1.51
Example 4 9.6 38.4 54.7 1.0 1.49
Example 5 3.3 43.3 56.2 1.0 1.49
Example 6 56.2 6.3 39.1 1.0 1.52
Example 7 63.3 1.3 36.9 1.0 1.52
Example 8 26.6 26.6 48.5 1.0 1.51
Example 9 26.6 26.6 48.5 1.0 1.51
Comparative Example 1 0 45.1 53.9 1.0 1.49
A: Terpene type epoxy resin B: 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate C: Methyl hexahydrophthalic anhydride D: Tetra-n-butylphosphonium o, o-diethyl phosphorodithioate Refractive index: Refractive index of epoxy resin layer without light diffusing agent

And the resin sheet shown in the said FIG. 2 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 FIG. 5 includes a drive 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 (33) at a running speed of 0.3 m / min, and dried at 100 ° C. for 10 minutes using the dryer (29). A 3.7 μm gas barrier layer (34) was formed. Further, the light diffusing agent-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 30 ° C. at 150 ° C. using the dryer (30). The epoxy resin layer (39) having a thickness of 400 μm was formed by curing for minutes. In this way, a laminate (40) is obtained in which the epoxy resin layer (39) in which the light diffusing agent is uniformly dispersed is laminated on the hard coat layer (33) via the gas barrier layer (34). It was. In addition, except not containing the said light diffusing agent, the result of having similarly formed the light diffusing agent addition epoxy-type resin layer and measuring the refractive index is shown according to the said Table 1 (hereinafter the same). .

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 laminate thus obtained was used as a resin sheet (Examples 1 to 7 and Comparative Example 1).
(Example 8)
As the light diffusing agent, silsesquisiloxane having an average particle diameter of 4 μm and a refractive index of 1.45 (trade name Tospearl 145: manufactured by Toshiba Silicone Co., Ltd.) was used instead of silica particles, and the addition amount was 7.56 parts. A resin sheet was prepared in the same manner as in Example 1 except for the above.
Example 9
As the light diffusing agent, a benzoquamine / melamine / formamide condensate (trade name: Eposta M30: manufactured by Nippon Shokubai Co., Ltd.) having an average particle diameter of 3 μm and a refractive index of 1.52 is used instead of silica particles. A resin sheet was produced in the same manner as in Example 1 except that the amount was 56 parts.

  The following evaluation tests were performed on the resin sheets of Examples 1 to 9 and Comparative Example 1 obtained as described above.

1. Glass transition temperature (℃)
About each said resin sheet, a viscoelastic spectrum was measured using the viscometer spectrometer apparatus (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 the 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. 3 as mentioned above using the autograph (made by Shimadzu Corporation). The thickness of the solid surface flat plate 12 and the flat plate 13 having a hole with a diameter of 20 mm was 30 mm, and the material was stainless steel. Further, the back surface of the resin sheet 40 (the back surface of the hard coat layer 33) was scratched with paper having a particle size of # 2000. And when the depth of the damage | wound was measured with 5 points | pieces and the roughness meter (brand name P-11: product made from a Tencor company) at random, all the points were 0.3 micrometer. In addition, all the resin sheets were the same result.

4). Evaluation of glare Using each of the resin sheets as a liquid crystal cell substrate, a liquid crystal display device was produced by a conventionally known method. And the glare of the display screen was observed visually.

5. Comprehensive evaluation From the evaluation results 1 to 4, the practicality of using each resin sheet as a liquid crystal cell substrate was evaluated based on the following evaluation criteria.

  A: Evaluation of glass transition point, light transmittance, breaking strength, and glare were all good.

  B: One of glass transition point, light transmittance, breaking strength, and glare can withstand practical use but is inferior.

  C: Two of the evaluations of glass transition point, light transmittance, breaking strength, and glare can be practically used, but they are inferior.

  D: At least one of the evaluation of glass transition point, light transmittance, breaking strength, and glare was a level that could not be continued in practical use.

  These results are shown in Table 2 below.

前記表２に示すように、テルペン型エポキシ樹脂を含まない比較例１の樹脂シートは、ガラス転移温度（Ｔｇ）および光透過性は優れるものの、破断強度が１５Ｎと低い値であり、強靭性が不十分な結果であった。そして、この比較例１の樹脂シートを用いて液晶表示装置を組み立て、運送した際には、前記樹脂シートが割れるという現象が見られた。これに対して、実施例１〜９の樹脂シートは、ガラス転移温度（Ｔｇ）および光透過性に優れるだけでなく、さらに優れた破断強度も併せ持つという特性を示した。このため、例えば、液晶セル基板等に適用すれば、耐熱性、光透過性、耐熱性、強靭性に優れ、軽量化や薄型化の液晶表示装置の提供が可能になる。これらの実施例の中でも、特に、エポキシ樹脂液におけるテルペン型エポキシ樹脂の含有割合を１２〜２８％に設定した実施例１、２、８、９においては、透過率およびガラス転移温度が高く、耐熱性と強靭性のバランスに優れた樹脂シートを得ることができた。

As shown in Table 2, the resin sheet of Comparative Example 1 that does not contain a terpene type epoxy resin has excellent glass transition temperature (Tg) and light transmittance, but has a low breaking strength of 15 N and high toughness. The result was insufficient. When the liquid crystal display device was assembled and transported using the resin sheet of Comparative Example 1, a phenomenon that the resin sheet cracked was observed. On the other hand, the resin sheet of Examples 1-9 showed the characteristic that it not only was excellent in glass transition temperature (Tg) and light transmittance, but also had the outstanding breaking strength. For this reason, for example, when applied to a liquid crystal cell substrate or the like, it is possible to provide a liquid crystal display device that is excellent in heat resistance, light transmittance, heat resistance, and toughness and is light and thin. Among these examples, in Examples 1, 2, 8, and 9 in which the content ratio of the terpene type epoxy resin in the epoxy resin liquid is set to 12 to 28%, the transmittance and the glass transition temperature are high, and the heat resistance is high. Resin sheet excellent in balance between strength and toughness could be obtained.

  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, when the light diffusing agent is further uniformly dispersed, 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 is prevented. be able to. Further, since the resin sheet itself has a light diffusion function, for example, it is not necessary to separately provide a light diffusion sheet or the like, and the liquid crystal cell can be made thinner and lighter.

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 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.

Explanation of symbols

1, 2, 11: Resin sheet 101: Light diffusing agent 102: Epoxy resin 201: Gas barrier layer 202: Hard coat 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: Driven drums 24, 25, 26, 27: Die 28: UV curing devices 29-32: Dryer 39: Epoxy resin layer in which the light diffusing agent is uniformly dispersed

Claims (16)

A particle dispersion resin sheet containing an epoxy resin and a particulate light diffusing agent,
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,
A particle-dispersed resin sheet, wherein the light diffusing agent is uniformly dispersed in 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 content ratio of the light diffusing agent is in a range of 0.1 to 60 parts by weight with respect to all epoxy resins. The particle-dispersed resin sheet according to any one of claims 1 to 5, wherein the average particle size of the light diffusing agent is in the range of 0.2 µm 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, and antimony oxide, according to any one of claims 1 to 6. Particle dispersion resin sheet. The absolute value of the difference between the refractive index of the epoxy resin and the refractive index of the light diffusing agent is a combination in a range of 0.03 to 0.30. Particle dispersion resin sheet. Furthermore, the particle-dispersed resin sheet as described in any one of Claims 1-8 containing a hard-coat layer. Furthermore, the particle-dispersed resin sheet as described in any one of Claims 1-9 containing a gas barrier layer. The particle transition resin sheet according to any one of claims 1 to 10, wherein a glass transition temperature (Tg) is 170 ° C or higher. The particle-dispersed resin sheet according to any one of claims 1 to 11, which has a light transmittance of 88% or more. The particle-dispersed resin sheet according to any one of claims 1 to 12, which has a breaking strength of 45 N or more. The board | substrate for image displays containing the particle-dispersed resin sheet as described in any one of Claims 1-13. An image display device comprising the substrate for an image display device according to claim 14. The board | substrate for solar cells containing the particle-dispersed resin sheet as described in any one of Claims 1-13.

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