JP5426330B2 - Transparent substrate / glass plate / transparent substrate composite film and its use - Google Patents

Description

  The present invention relates to a composite film in which a glass plate is laminated on a transparent substrate containing a resin and its use.

  The organic electroluminescence light emitting element has a structure in which a light transmissive substrate such as glass or plastic, an anode made of a transparent conductive film, an organic light emitting layer made of an organic thin film, and a cathode made of a metal thin film are laminated. In recent years, various types of lighting, backlights for liquid crystal display devices, flat panel displays, etc. have been developed. Used in the field.

  In addition, portable display devices are required to be thin, lightweight, and have low power consumption. Electrophoretic electronic paper is expected to meet these requirements. For example, electrophoretic electronic paper has a configuration in which a microcapsule in which a dispersion liquid in which white negatively charged particles and black positively charged particles are dispersed is enclosed between a plurality of pixel electrodes and a transparent common electrode. doing. When an electric field is applied between these electrodes, the positively charged particles and the negatively charged particles are moved to either the pixel electrode or the common electrode by receiving an electrostatic force in a direction corresponding to the positive or negative charge, and a contrast is obtained. It is like that.

  In recent years, organic electroluminescence light-emitting elements, electrophoretic electronic paper, and the like have been further reduced in weight and thickness, and those having flexibility have been demanded.

  Therefore, for example, a surface protection film that protects the surface of a top emission type organic electroluminescence display, a top emission type organic electroluminescence illumination, an electrophoretic electronic paper, or the like is required to have flexibility.

  Such surface protective film has characteristics such as transparency, heat resistance, mechanical strength, chemical resistance, suppression of thermal expansion, suppression of gas release in a high vacuum in the device manufacturing process, gas barrier property, surface smoothness, etc. Need to be satisfied.

  As a lightweight, thin and flexible film considering such various characteristics, a composite film in which a glass plate is laminated on a transparent substrate such as a resin has been studied. For example, Patent Document 1 proposes a composite film in which a thin glass plate having a thickness of less than 0.25 mm is directly laminated on both surfaces of a polyvinyl butyral transparent adhesive resin layer as a base material used in a liquid crystal display device or the like. .

  Patent Document 2 does not have flexibility, but as a technique for laminating a glass plate on a transparent substrate, a glass fiber base material is impregnated with a resin composition, dried and semi-cured. Making a prepreg, laminating a glass plate having a thickness of 1.8 to 6 mm on both sides of the prepreg, and heating and pressing to cure the prepreg, thereby producing a laminated glass used for an automobile windshield or the like. Proposed.

Japanese Patent No. 3059866 JP 2004-338965 A

  However, the technique described in Patent Document 1 has a problem that cracks occur in the composite film due to bending.

  Moreover, like the technique of patent document 2, when laminating | stacking a glass plate to a prepreg and heat-press-molding, if a thin glass plate is used in order to obtain a flexible base material, a glass plate will be carried out by heat-press molding. There was a problem that cracks occurred.

  The present invention has been made in view of the circumstances as described above, and satisfies various properties required for a surface protection film of a display device or a lighting device, has flexibility, and further is flexible. It is an object to provide a composite film having crack resistance and its application.

  The present invention is characterized by the following in order to solve the above problems.

  First, the transparent substrate / glass plate / transparent substrate composite film of the present invention comprises two transparent substrates in which a transparent resin is held on a glass fiber substrate, and one glass plate having a thickness of 50 μm or less. In addition, a transparent substrate is laminated on each of both surfaces of the glass plate, and it is assumed that cracks do not occur when the glass substrate is wound and installed on the outer peripheral surface of a cylinder having a diameter of 15 cm for 60 seconds.

  Second, the first transparent substrate / glass plate / transparent substrate composite film has an adhesive layer between the transparent substrate and the glass plate.

  Third, in the second transparent substrate / glass plate / transparent substrate composite film, the refractive index of the adhesive layer is in the range of n−0.02 to n + 0.02 with respect to the refractive index n of the glass fiber of the transparent substrate. It is.

  Fourthly, a top emission type organic electroluminescence display of the present invention includes any one of the first to third transparent substrate / glass plate composite films as a surface protective film.

  Fifth, the top emission type organic electroluminescence illumination of the present invention includes any one of the first to third transparent substrate / glass plate composite films as a surface protective film.

  Sixth, an electrophoretic electronic paper of the present invention includes any one of the first to third transparent substrate / glass plate composite films as a surface protective film.

  According to the first aspect of the present invention, two transparent substrates obtained by impregnating a glass fiber base material with a transparent composition, in which a transparent resin is held on the glass fiber base material, and curing the resin composition are used. Since the glass plate having a thickness of 50 μm or less is sandwiched between the two transparent substrates and the transparent substrate is laminated on each of both surfaces of the glass plate, the surface protective film for display devices and lighting devices Various properties required for such as transparency, heat resistance, mechanical strength, chemical resistance, suppression of thermal expansion, suppression of gas release in high vacuum in the element manufacturing process, gas barrier properties, surface smoothness, etc. Satisfied and flexible. Further, it has a high crack resistance against bending, and no cracks are generated even when it is wound around the outer peripheral surface of a cylinder having a diameter of 15 cm for 60 seconds.

  According to the second invention, since the transparent substrate and the glass plate are bonded by the adhesive layer, in addition to the effects of the first invention, the transparent substrate and the glass plate are not required without excessive heating or pressurization. Even when a glass plate having a thickness of 50 μm or less is used, generation of cracks can be prevented during production of the transparent substrate / glass plate / transparent substrate composite film.

  According to the third aspect of the invention, the refractive index of the adhesive layer is in the range of n−0.02 to n + 0.02 with respect to the refractive index n of the glass fiber of the transparent substrate, so In addition to the effects of the invention, the transparency of the transparent substrate / glass plate / transparent substrate composite film can be enhanced.

  According to the fourth to sixth inventions, since the transparent substrate / glass plate / transparent substrate composite film of the first to third inventions is provided as a surface protective film, the top emission type organic electroluminescence display, the top While satisfying various properties required for the surface protection film of emission organic electroluminescence illumination and electrophoretic electronic paper, it can provide flexibility and also has crack resistance against bending.

  Hereinafter, the present invention will be described in detail.

  The transparent substrate used in the present invention is one in which a transparent resin is held on a glass fiber base material, and the resin composition used for its production is a high refractive index resin having a refractive index larger than that of glass fiber, It is prepared by mixing a low refractive index resin having a refractive index smaller than that of glass fiber so that the refractive index approximates that of glass fiber.

  As the high refractive index resin having a higher refractive index than that of glass fiber, for example, a cyanate ester resin can be used.

  Examples of cyanate ester resins include 2,2-bis (4-cyanatephenyl) propane, bis (3,5-dimethyl-4-cyanatephenyl) methane, 2,2-bis (4-cyanatephenyl) ethane, and the like. Or an aromatic cyanate ester compound can be used. These may be used alone or in combination of two or more.

  Cyanate ester resin generates a triazine ring or an oxazoline ring by causing a curing reaction together with the epoxy resin, increases the crosslink density of the epoxy resin, and forms a rigid structure to give the cured product a high glass transition temperature. Can do. In addition, since the cyanate ester resin is solid at room temperature, when preparing a prepreg by impregnating the resin composition into a glass fiber base material and drying it as described later, it becomes easy to dry by touch. The handleability of the prepreg is improved.

  Further, as the high refractive index resin, an epoxy resin such as a polyfunctional epoxy resin can be used alone or in combination with a cyanate ester resin. As a polyfunctional epoxy resin, what is represented, for example by following formula (I) can be used.

(In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents a divalent organic group, and R ^{3 to} R ¹⁰ each independently represent a hydrogen atom, a substituent, or an epoxy group-containing molecular chain. .)
By using this polyfunctional epoxy resin represented by the above formula (I), it is possible to increase the heat resistance of the cured product because of its high glass transition temperature while maintaining high transparency, and further discoloration due to heat. Can also be suppressed.

Examples of the divalent organic group represented by R ² in the formula (I) include a substituted or unsubstituted arylene group such as a phenylene group, or a structure in which a substituted or unsubstituted arylene group is bonded to a carbon atom or a carbon chain. Groups and the like. Examples of the carbon atom or carbon chain include an alkylene group such as a methylmethylene group and a dimethylmethylene group, and a carbonyl group.

As the divalent organic group represented by R ^2, a group that forms a glycidyloxyphenyl group by bonding a phenylene group to the glycidyloxy group on the right side of the formula (I) is preferably used. Further, from the viewpoint of suppressing discoloration of the transparent film due to heat, a carbon atom or carbon chain interposed between arylene groups preferably does not contain a methylene group (—CH ₂ —).

Examples of the divalent organic group represented by R ² include the following structures (inside square brackets).

Examples of the substituent of R ³ to R ¹⁰ in the formula (I), is not particularly limited, for example, hydrocarbon groups such as lower alkyl groups, such as other organic groups. Examples of the molecular chain containing an epoxy group of R ^{3 to} R ¹⁰ include the following structures (inside square brackets).

(In the formula, p represents a positive integer.)
As the polyfunctional epoxy resin represented by the formula (I), for example, polyfunctional epoxy resins represented by the following formulas (Ia), (Ib), and (Ic) can be used.

(In the formula, q represents a positive integer.)

  The refractive index of the high refractive index resin is preferably 1.58 to 1.63. For example, when the refractive index of the glass fiber is 1.563, the high refractive index resin preferably has a refractive index of around 1.6. When the refractive index of the glass fiber is n, n + 0.03 to n + 0.06. Those within the range are preferred.

  In the present invention, the refractive index of the resin means the refractive index in the state of cured resin (cured resin), and is a value tested by ASTM D542.

  In the present invention, an epoxy resin can be used as the low refractive index resin having a refractive index smaller than that of the glass fiber. Among these, a polyfunctional epoxy resin having a structure represented by the following formula (II) is preferably used.

(In the formula, R represents an m-valent organic group, and m and n represent positive integers.)
The polyfunctional epoxy resin having a structure represented by the formula (II) is alicyclic and highly transparent, has a high glass transition temperature, and can improve the heat resistance of the cured product.

  In the formula (II), the organic group R may be arbitrary as long as the effect of the present invention based on the alicyclic epoxy structure in the square brackets is not impaired. Examples include branched hydrocarbon groups. M in the formula (II) is not particularly limited, but is, for example, 1 to 5, and n is not particularly limited, but is preferably in a range that loses fluidity at normal temperature (25 ° C.) and becomes solid. By being solid at normal temperature, the production of the transparent substrate can be facilitated.

  As a polyfunctional epoxy resin having a structure represented by the formula (II), for example, 1,2-epoxy-4- (2-oxiranyl) cyclohexane is added to 2,2-bis (hydroxymethyl) -1-butanol. What is obtained can be used. Specifically, for example, those represented by the following formula (II-a) can be used.

(In the formula, three n's each independently represent a positive integer.)
For example, the polyfunctional epoxy resin has a melting point of about 85 ° C. and the molecular weight is not particularly limited, but is, for example, 2000 to 3000 in terms of weight average molecular weight.

  In addition to the polyfunctional epoxy resin having a structure represented by the formula (II), for example, a hydrogenated bisphenol type epoxy resin can be used as the low refractive index resin. As the hydrogenated bisphenol type epoxy resin, for example, bisphenol A type, bisphenol F type, bisphenol S type and the like can be used. Preferably, a hydrogenated bisphenol type epoxy resin that is solid at room temperature is used. Although hydrogenated bisphenol-type epoxy resin that is liquid at room temperature can be used, when preparing a prepreg by impregnating the resin composition into a glass fiber base material and drying it, it becomes sticky to the touch. However, in many cases, the prepreg cannot be dried, and the handling property of the prepreg may be deteriorated.

  In the present invention, the refractive index of the low refractive index resin is preferably 1.47 to 1.53. For example, when the refractive index of the glass fiber is 1.563, the low refractive index resin preferably has a refractive index of around 1.5. When the refractive index of the glass fiber is n, n−0.04 to n−. The thing of the range of 0.08 is preferable.

  The mixing ratio of the high refractive index resin and the low refractive index resin in the resin composition is arbitrarily adjusted so as to approximate the refractive index of the glass fiber. Here, it is desirable that the refractive index of the resin composition is as close as possible to the refractive index of the glass fiber, but when the refractive index of the glass fiber is n, it is approximated within a range of n−0.02 to n + 0.02. It is preferable to adjust.

  The ratio between the high refractive index resin and the low refractive index resin is that, from the point of matching the refractive index of the resin to the refractive index of the E glass fiber when using E glass fiber that is inexpensive and stable in supply quality as the glass fiber. The mass ratio is preferably in the range of 40:60 to 55:45.

  The resin composition is preferably prepared so that the glass transition temperature (Tg) of the cured resin is 150 ° C. or higher. When the glass transition temperature is 150 ° C. or higher, the heat resistance of the transparent substrate can be increased. The upper limit of the glass transition temperature is not particularly limited, but practically about 280 ° C. is the upper limit of the glass transition temperature.

  In the present invention, the glass transition temperature is a value measured according to the JIS C6481 TMA method.

  In the present invention, a curing initiator (curing agent) can be blended in the resin composition. As the curing initiator, for example, an organic metal salt can be used. Examples of the organic metal salts include salts of organic acids such as octanoic acid, stearic acid, acetylacetonate, naphthenic acid, and salicylic acid with metals such as Zn, Cu, and Fe. These may be used alone or in combination of two or more. Of these, zinc octoate is preferable. By using zinc octoate as the curing initiator, the glass transition temperature of the cured resin can be increased. The amount of the organic metal salt such as zinc octoate in the resin composition is preferably in the range of 0.01 to 0.1 PHR.

  A cationic curing agent can also be used as the curing initiator. By using a cationic curing agent, the transparency of the cured resin can be increased. Examples of the cationic curing agent include aromatic sulfonium salts, aromatic iodonium salts, aromatic ammonium salts, aluminum chelates, and boron trifluoride amine complexes. The blending amount of the cationic curing agent in the resin composition is preferably in the range of 0.2 to 3.0 PHR.

  Further, a curing catalyst such as a tertiary amine such as triethylamine or triethanolamine, 2-ethyl-4-imidazole, 4-methylimidazole, 2-ethyl-4-methylimidazole or the like can also be used as a curing initiator. The blending amount of the curing catalyst in the resin composition is preferably in the range of 0.5 to 5.0 PHR.

  The resin composition can be prepared by blending the high refractive index resin, the low refractive index resin, and a curing initiator as necessary. This resin composition can be prepared as a varnish by diluting with a solvent as necessary. Examples of the solvent include benzene, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, acetone, methanol, ethanol, isopropyl alcohol, 2-butanol, ethyl acetate, butyl acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diacetone. Alcohol, N, N′-dimethylacetamide and the like can be mentioned.

  Although it does not specifically limit as a glass fiber which comprises the base material of a glass fiber, From the point which raises the impact resistance of a transparent film, and the point that supply quality is stable cheaply, the fiber of E glass or NE glass is used. Preferably used. The E glass fiber is also called an alkali-free glass fiber, and is a glass fiber that is widely used as a glass fiber for resin reinforcement. NE glass is NewE glass. T glass fibers can also be used. T glass has better mechanical and thermal properties than general-purpose E glass.

  Moreover, it is preferable to surface-treat glass fiber with the silane coupling agent normally used as a glass fiber processing agent in order to improve impact resistance. The refractive index of the glass fiber is preferably 1.55 to 1.57, more preferably 1.555 to 1.565. If the refractive index of glass fiber is this range, the transparent substrate excellent in visibility can be obtained. As the glass fiber substrate, a glass fiber woven fabric or non-woven fabric can be used.

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

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

  In the transparent substrate obtained as described above, a resin matrix formed by polymerizing a high refractive index resin and a low refractive index resin has a high glass transition temperature, and a transparent film excellent in heat resistance is obtained. be able to.

  Moreover, the high refractive index resin and the low refractive index resin as exemplified above are excellent in transparency, and a transparent substrate ensuring high transparency can be obtained. In this transparent substrate, the glass fiber base material content is preferably in the range of 25 to 65 mass%, more preferably in the range of 35 to 60 mass%. If it is this range, while being able to obtain high impact resistance with the reinforcement effect by glass fiber, sufficient transparency can be obtained. Moreover, when there are too many glass fibers, the surface unevenness | corrugation will become large and transparency will also fall. On the other hand, when there are too few glass fibers, the thermal expansion coefficient of a transparent substrate may become large.

  Note that a plurality of thin glass fiber substrates can be used in order to obtain high transparency. Specifically, a glass fiber substrate having a thickness of 50 μm or less can be used, and two or more of them can be used in an overlapping manner. The thickness of the glass fiber substrate is not particularly limited, but about 10 μm is a practical lower limit. The number of glass fiber substrates is not particularly limited, but about 20 is the practical upper limit. Thus, when manufacturing a transparent substrate using a plurality of glass fiber base materials, each glass fiber base material is impregnated with a resin composition and dried to prepare a prepreg, and a plurality of the prepregs are stacked. A transparent substrate can be obtained by heat and pressure molding. However, the resin composition is impregnated and dried in a state in which a plurality of glass fiber base materials are stacked, and a prepreg is produced by heating and pressure molding the prepreg. Thus, a transparent substrate may be obtained.

  The transparent substrate / glass plate / transparent substrate composite film of the present invention can be produced as follows using the transparent substrate and glass plate described above.

  A glass plate having a thickness of 50 μm or less, preferably 20 to 40 μm is used. By using a glass plate having such a thickness, crack resistance against bending can be obtained.

  The material of the glass plate is not particularly limited, and for example, borosilicate glass, soda lime glass, alkali-free glass, sol-gel glass, or the like can be used. The method for producing the glass plate is not particularly limited, and for example, a redraw method, a downdraw method, a fusion method, a microsheet method, a sol-gel method, or the like can be used.

  The transparent substrate and the glass plate are bonded by an adhesive layer. As the resin composition for forming an adhesive layer for forming this adhesive layer, a resin composition containing a resin that is solid at room temperature (20 ° C.) containing an epoxy resin can be used.

  As an epoxy resin, if it is solid at normal temperature as a whole resin component of the resin composition for contact bonding layer formation, in addition to a solid at normal temperature, a liquid thing at normal temperature can be combined and used. The epoxy resin is not particularly limited. For example, 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, ε-caprolactone modified 3,4-epoxycyclohexenylmethyl-3 ′, 4 ′. -An alicyclic epoxy resin containing a 3,4-epoxycyclohexenyl skeleton such as epoxycyclohexanecarboxylate, a polyfunctional epoxy resin having a structure represented by the above formula (II), other polyfunctional epoxy resins, solid or liquid Bisphenol type epoxy resin, novolac type epoxy resin and the like.

  It is preferable that the resin component of the resin composition for forming an adhesive layer adjusts the glass transition temperature and the refractive index of the adhesive layer by mixing a plurality of types of resins, particularly a plurality of types of epoxy resins.

  The resin composition for forming an adhesive layer is preferably prepared so that the glass transition temperature of the adhesive layer is 150 ° C. or higher. When the glass transition temperature is 150 ° C. or higher, the heat resistance of the transparent substrate can be increased.

  The resin composition for forming an adhesive layer is desirably adjusted so that the refractive index of the adhesive layer is as close as possible to the refractive index of the glass fiber, where n−0.02 to n + 0. It is preferable to adjust so as to approximate within the range of 02. For example, an epoxy resin having a refractive index larger than that of glass fiber and an epoxy resin having a refractive index smaller than that of glass fiber can be mixed and adjusted so that the refractive index approximates the refractive index of glass fiber.

  A curing initiator (curing agent) can be blended in the adhesive layer forming resin composition. As this curing initiator, it is preferable to use a photocationic curing initiator such as a boron-based onium salt that can be cured by ultraviolet rays.

  The resin composition for forming an adhesive layer can be prepared by blending the above resin component and, if necessary, a curing initiator. This adhesive layer-forming resin composition can be prepared as a varnish by diluting with a solvent. Examples of the solvent include benzene, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, acetone, methanol, ethanol, isopropyl alcohol, 2-butanol, ethyl acetate, butyl acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, Acetone alcohol, N, N'-dimethylacetamide, etc. are mentioned.

  When two transparent substrates and a glass plate are laminated and integrated using this adhesive layer forming resin composition, for example, the adhesive layer forming resin composition is first applied to a transfer film and dried to form an adhesive layer. The forming resin layer is used. Then, the adhesive layer forming resin layer provided on the transfer film is transferred to both surfaces of the glass plate, a transparent substrate is arranged on both sides of the transferred adhesive layer forming resin layer, and vacuum lamination is performed to integrate them. Alternatively, the adhesive layer forming resin layer provided on the transfer film is transferred to one side of two transparent substrates, and a glass plate is placed between the two transparent substrates with the transferred adhesive layer forming resin layer inside. And vacuum laminate to integrate.

  As the transfer film, for example, a release film based on a resin film such as PET can be used.

  Alternatively, the adhesive layer forming resin composition is applied to one side of two transparent substrates and dried to provide an adhesive layer forming resin layer, and between the two transparent substrates with the adhesive layer forming resin layer inside. A glass plate can also be arranged and integrated by vacuum lamination.

  The vacuum lamination is preferably performed by heating two transparent substrates and one glass plate to a temperature not lower than the melting temperature of the adhesive layer forming resin layer and lower than the glass transition temperature of the transparent substrate. By doing in this way, a transparent substrate and a glass plate can be closely_contact | adhered and adhere | attached with the fuse | melted resin layer for adhesive layer formation, without carrying out the heat deformation of a transparent substrate.

  Vacuum lamination can be performed using a commercially available pressure-type vacuum laminator. For example, since lamination can be performed under conditions of about 0.2 MPa, cracks are generated in a thin glass plate having a thickness of 50 μm or less due to excessive pressure. Can be prevented.

  In this way, when the transparent substrate and the glass plate are integrated with the adhesive layer forming resin layer sandwiched therebetween, and the above-mentioned photocationic curing initiator is blended in the adhesive layer forming resin composition, the adhesive layer is formed. The adhesive resin layer can be formed by semi-curing the resin layer by irradiation with light such as ultraviolet rays and then thermally curing the semi-cured adhesive layer-forming resin layer. For example, if the thermosetting is performed at 150 ° C. for about 30 minutes, the adhesive layer can be completely cured.

The transparent substrate / glass plate / transparent substrate composite film of the present invention has transparency, heat resistance, mechanical strength, chemical resistance, suppression of thermal expansion, suppression of gas release in a high vacuum in a device manufacturing process, gas barrier property, surface While satisfying smoothness etc., it has flexibility, and also has crack resistance against bending. For example, it is assumed that cracking does not occur in a flexibility test of 10 cmφ or less, the water vapor transmission rate is 1 × 10 ⁻² g / m ² d or less, and the average thermal expansion coefficient at 50 to 150 ° C. is less than 10 ppm. it can. Therefore, the transparent substrate / glass plate / transparent substrate composite film of the present invention can be applied to various fields, and among them, surface protection films for display devices and lighting devices, in particular, top emission type organic electroluminescence displays, top emission. It can be suitably used as a surface protective film for type organic electroluminescence illumination and electrophoretic electronic paper.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.
<Example 1>
As a high refractive index resin, a solid cyanate ester resin (Lonza, BADCy, 2,2-bis (4-cyanatophenyl) propane, refractive index 1.59) is 52 parts by mass, as a low refractive index resin, 48 parts by mass of a solid epoxy resin containing a skeleton derived from 1,2-epoxy-4- (2-oxiranyl) cyclohexane (manufactured by Daicel Chemical Industries, Ltd., EHPE3150, refractive index 1.51) and further cured Prepare 0.02 parts by mass of zinc octoate as an initiator, add 50 parts by mass of toluene as a solvent and 50 parts by mass of methyl ethyl ketone, and prepare a varnish of a resin composition by stirring and dissolving at 70 ° C. did. The refractive index of the cured product of this resin composition was 1.56.

  Next, a glass fiber cloth having a thickness of 25 μm (manufactured by Asahi Kasei Electronics Co., Ltd., product number 1037, E glass fiber, refractive index 1.56) is used as the glass fiber base material. And the solvent was removed by heating at 150 ° C. for 5 minutes, and the resin was semi-cured to prepare a prepreg.

  Then, the prepreg is sandwiched between the mold glass plates subjected to the mold release treatment and set in a press machine, and the resin content is 48% by mass and the thickness is formed by heating and pressing under conditions of 170 ° C., 2 MPa, 15 minutes. A 26 μm transparent substrate was obtained. The glass transition temperature of the obtained transparent substrate was 230 ° C.

  Meanwhile, 10 parts by mass of an epoxy resin containing 3,4-epoxycyclohexenyl skeleton (manufactured by Daicel Chemical Industries, Ltd., Celoxide 2081), 15 parts by mass of liquid bisphenol-type epoxy resin (manufactured by DIC Corporation, Epicron 830S), solid 40 parts by mass of a bisphenol type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., JER1006FS), 35 parts by mass of a solid bisphenol type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., JER4007), a photocationic curing initiator (ADEKA) Manufactured by SL-170), 1 part by weight of a surface conditioner (manufactured by DIC Corporation, F470), 21 parts by weight of toluene and 49 parts by weight of methyl ethyl ketone were weighed in a glass container and refluxed to 60 parts. PTFE membrane filter with 1 μm opening after melting at ℃ By filtration, to prepare a varnish of adhesive layer-forming resin composition.

  Next, the varnish of the resin composition for forming an adhesive layer is formed on the surface of a transfer film (manufactured by Teijin DuPont, OX-50, release film made of PET) using a multi-coater of gravure head (manufactured by Hirano Techseed Co., Ltd.). By applying and drying, a transfer laminate film having a 1 μm-thick adhesive layer-forming resin layer was obtained.

  This transfer laminate film was laminated on one side of the transparent substrate obtained above using a pressure-type vacuum laminator (manufactured by Nichigo Morton Co., Ltd., V-130) at 80 ° C. and 0.2 MPa, and then released. The film was removed. Two transparent substrates with an adhesive layer forming resin layer were prepared, and an adhesive layer forming resin layer was provided on each of both surfaces of a 0.03 mm thick glass plate (Matsunami Glass Industry Co., Ltd., D263, ultrathin glass). The transparent substrate was placed with the adhesive layer forming resin layer inside, and vacuum laminated under the same conditions as above.

Next, after semi-curing the resin composition for forming an adhesive layer with ultraviolet rays of 1800 mJ / cm ² , it was completely cured by heat treatment at 150 ° C. for 30 minutes, and a transparent substrate / glass plate / transparent substrate composite film specimen Was made.
<Example 2>
As a glass plate laminated on the transparent substrate, a glass plate having a thickness of 0.05 mm (manufactured by Matsunami Glass Industry Co., Ltd., D263, ultra-thin glass) was used, and otherwise, the transparent substrate / glass plate / A transparent substrate composite film test product was prepared.
<Example 3>
As the glass fiber base material, a glass fiber cloth having a thickness of 20 μm (manufactured by Asahi Kasei Electronics Co., Ltd., product number 1027, E glass fiber, refractive index 1.56) was used. A glass plate / transparent substrate composite film test product was prepared.
<Example 4>
As a glass plate to be laminated on the transparent substrate, a glass plate having a thickness of 0.05 mm (manufactured by Matsunami Glass Industry Co., Ltd., D263, ultra-thin glass) was used, and otherwise the transparent substrate / glass plate / A transparent substrate composite film test product was prepared.
<Comparative Example 1>
In Example 1, the transfer laminate film was laminated on both sides of the transparent substrate, the release film was removed, and a glass plate having a thickness of 0.03 mm (Matsunami Glass on each side of the transparent substrate with the adhesive layer forming resin layer). Kogyo Co., Ltd., D263, ultrathin glass) was placed and vacuum laminated.

Next, after semi-curing the resin composition for forming an adhesive layer with ultraviolet rays of 1800 mJ / cm ² , it was completely cured by heat treatment at 150 ° C. for 30 minutes, and a glass plate / transparent substrate / glass plate composite film specimen Was made.
<Comparative example 2>
Only the transparent substrate of Example 1 was used as a test product.

The following evaluation was performed about each test article of the Example and comparative example which were produced above.
[transparency]
It measured based on JISK7136 using Nippon Denshoku Industries Co., Ltd. make haze meter NDH2000.
[Crack resistance (flexibility test)]
A test product was wound around the outer peripheral surface of a cylindrical resin having a diameter of 10, 15, and 20 cm for 60 seconds, and the occurrence of cracks was visually observed and evaluated according to the following criteria.
○: No cracks were observed.
X: A crack occurred.
[Gas barrier properties (water vapor permeability)]
The water vapor transmission rate of the test product was measured by the MOCON method according to JISK7129 B and ASTM F1249.
[Coefficient of thermal expansion (CTE)]
Based on JISC 6481, it was measured by the TMA method (Thermo-mechanical analysis). A thermal expansion coefficient at 30 to 100 ° C. was measured in a tensile mode using a 15 mm sample with “EXSTAR6000” manufactured by Seiko Instruments Inc.
[Surface smoothness (surface roughness)]
The surface roughness (Ra value) of the test product was measured using a stylus type surface roughness meter SURFCOM 130A manufactured by Tokyo Seimitsu Co., Ltd. The measurement range was 4 mm, and the arithmetic average Ra value was calculated during this period.

  The evaluation results are shown in Table 1.

  From Table 1, the transparent substrate / glass plate / transparent substrate composite film prepared in Examples 1 to 4, ie, a glass fiber base material impregnated with a resin composition prepared to approximate the refractive index of glass fiber, A transparent substrate / glass plate / transparent substrate composite film in which two transparent substrates formed by curing are laminated and integrated on both sides of a glass plate having a thickness of 50 μm or less has high transparency, a low thermal expansion coefficient, and a gas barrier. And high surface smoothness. Furthermore, it had crack resistance against bending, and no crack was observed at 15 cmφ.

  On the other hand, the glass plate / transparent substrate / glass plate composite film produced in Comparative Example 1 had cracks due to bending at 15 cmφ, and crack resistance to bending was lower than in Examples 1 to 4.

  In Comparative Example 2, the transparent substrate was used alone without being combined with the glass plate, but in terms of gas barrier properties and thermal expansion coefficient, characteristics were deteriorated as compared with Examples 1 to 4.

Claims (9)

It is provided with two transparent substrates in which a transparent resin is held on a glass fiber substrate and one glass plate having a thickness of 50 μm or less, and the transparent substrates are laminated on both sides of the glass plate, and the diameter is A top emission type organic electroluminescence display comprising a transparent substrate / glass plate / transparent substrate composite film that does not generate cracks when wound around an outer peripheral surface of a 15 cm cylinder for 60 seconds. . The top emission type organic electroluminescence display according to claim 1, wherein the transparent substrate / glass plate / transparent substrate composite film has an adhesive layer between the transparent substrate and the glass plate . The transparent substrate / glass plate / transparent substrate composite film is characterized in that the refractive index of the adhesive layer is in the range of n−0.02 to n + 0.02 with respect to the refractive index n of the glass fiber of the transparent substrate. The top emission type organic electroluminescence display according to claim 2 . It is provided with two transparent substrates in which a transparent resin is held on a glass fiber substrate and one glass plate having a thickness of 50 μm or less, and the transparent substrates are laminated on both sides of the glass plate, and the diameter is A top emission type organic electroluminescence illumination comprising a transparent substrate / glass plate / transparent substrate composite film that does not generate cracks when installed on an outer peripheral surface of a 15 cm cylinder for 60 seconds. . The top emission type organic electroluminescence illumination according to claim 4, wherein the transparent substrate / glass plate / transparent substrate composite film has an adhesive layer between the transparent substrate and the glass plate . The transparent substrate / glass plate / transparent substrate composite film is characterized in that the refractive index of the adhesive layer is in the range of n−0.02 to n + 0.02 with respect to the refractive index n of the glass fiber of the transparent substrate. The top emission type organic electroluminescence illumination according to claim 5 . It is provided with two transparent substrates in which a transparent resin is held on a glass fiber substrate and one glass plate having a thickness of 50 μm or less, and the transparent substrates are laminated on both sides of the glass plate, and the diameter is An electrophoretic electronic paper comprising a transparent substrate / glass plate / transparent substrate composite film as a surface protective film that does not generate cracks when wound around an outer peripheral surface of a 15 cm cylinder for 60 seconds . The electrophoretic electronic paper according to claim 7, wherein the transparent substrate / glass plate / transparent substrate composite film has an adhesive layer between the transparent substrate and the glass plate . The transparent substrate / glass plate / transparent substrate composite film is characterized in that the refractive index of the adhesive layer is in the range of n−0.02 to n + 0.02 with respect to the refractive index n of the glass fiber of the transparent substrate. The electrophoretic electronic paper according to claim 8 .