JP2005014599A - Resin sheet and electroluminescence display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin sheet in which is formed by laminating an inorganic protecting film on an epoxy resin substrate and wherein the inorganic protecting film is hardly peeled off. <P>SOLUTION: The resin sheet comprises an epoxy resin substrate, a plasma polymer film obtained by plasma polymerization of a material containing a carbon atom, which is tightly laminated to the epoxy resin substrate, and an inorganic protecting film which is tightly laminated to the plasma polymer film. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a resin sheet in which an inorganic protective film for improving gas barrier properties is mainly laminated on an epoxy resin substrate.

  In recent years, in the field of electronic devices, plastic substrates are being used instead of glass substrates as substrates on which electronic devices are formed in order to reduce weight and thickness.

  As a substrate for this type of electronic device, heat resistance, chemical resistance, surface hardness, optical isotropy, low water absorption, and the like are required. Epoxy resins are preferable for such necessary characteristics. Therefore, various epoxy resin substrates have been proposed as the substrate (see, for example, Patent Documents 1 to 6).

  However, since electronic devices dislike foreign impurities (for example, water, oxygen, etc.), plastics have low shielding properties (gas barrier properties), and epoxy resins are no exception, so electronic devices are formed. When an epoxy resin is used as the substrate, it is necessary to laminate a protective film that improves gas barrier properties on the epoxy resin base material.

  By the way, as a protective film for improving the gas barrier property of the substrate, an inorganic protective film is excellent, and conventionally, various inorganic protective films used for glass substrates have been proposed (Patent Documents 7 to 12 below).

JP 63-144041 A JP-A-2-169620 Japanese Patent Laid-Open No. 3-16171 JP-A-6-337408 JP 7-28043 A Japanese Patent Laid-Open No. 13-59015 JP 63-259994 A JP 7-161474 A JP-A-4-73886 Japanese Patent Laid-Open No. 5-101885 JP-A-5-335080 Japanese Patent Application Laid-Open No. 8-96955

  However, these inorganic protective films have low adhesion to the epoxy resin. For example, the inorganic protective film is easily peeled off from the epoxy resin substrate in a state where thermal stress is applied under high temperature and high humidity conditions. This can cause problems.

Therefore, in view of the above problems, the present invention provides a resin sheet that can be hardly peeled off even though the inorganic protective film is laminated on the epoxy resin substrate.
It is another object of the present invention to provide an electroluminescence display device in which the resin sheet is used as a substrate for an electroluminescence element.

  As a result of intensive studies in view of the above problems, the present inventors have found that the above problems can be solved by interposing a predetermined film between the epoxy resin base material and the inorganic protective film. It came to be completed.

That is, the present invention comprises an epoxy resin base material, a plasma polymerized film obtained by plasma polymerizing a material containing carbon atoms, which is laminated in close contact with the epoxy resin base material, and the plasma polymerized film. Provided is a resin sheet comprising an inorganic protective film laminated in close contact.
In the resin sheet having such a configuration, since the plasma polymerization film exhibits good adhesion to the epoxy resin base material and the inorganic protective film, the inorganic protective film is difficult to peel off.

In the present invention, the action is considered as follows.
In general, the low adhesion between the organic material, which is an epoxy resin, and the inorganic material of the protective film is due to the weak chemical bond between the two materials, so the bond strength at the interface depends on the van der Waals force and This is because the van der Waals force acting on the interface itself is not so large because the density of the resin is relatively low. In addition, poor wettability between organic and inorganic substances is also a cause of low adhesion.
Furthermore, in addition to the internal stress contained in the formed protective film, stress generated by the difference in expansion coefficient from the epoxy resin base material is applied under severe environments such as high temperature and high humidity conditions, It becomes easier to peel off.
On the other hand, a plasma polymerized film obtained by plasma polymerizing a material containing carbon atoms has good paintability with an organic substance and improves adhesion.
Furthermore, the radicals and ions generated during the plasma polymerization further strengthen the chemical bond with the compound that constitutes the surface of the epoxy resin substrate, thereby improving the adhesion.
Therefore, as described above, the inorganic protective film is difficult to peel off.

  Further, in the above configuration, since the plasma polymerization is performed by the vapor phase growth method, it becomes easy to form a film on a substrate having various shapes.

Further, in the above configuration, many plasma polymerized films obtained by plasma polymerization of a material containing carbon atoms have higher stress relaxation properties than the inorganic protective film, the thermal stress of the inorganic protective film, and the inorganic protective film. When an element is formed on the element, the thermal stress of the element can be reduced, and the gas barrier property and the element characteristic can be reduced little.
In the above configuration, the thickness of the inorganic protective film having high gas barrier properties but low bending stress resistance is reduced to increase the bending stress resistance, and the gas barrier property that is reduced accordingly is excellent in stress relaxation and bending stress resistance. Can be supplemented by high plasma polymerized film stacking (especially multilayer stacking). For this reason, the resin sheet of the present invention can also have high bending stress resistance and high gas barrier properties.

The present invention also includes an epoxy resin substrate and an inorganic protective film laminated in close contact with the epoxy resin substrate, and the surface to be laminated of the epoxy resin substrate is subjected to UV ozone treatment. A resin sheet is provided.
If UV ozone treatment is applied to a general plastic substrate, it will be modified not only to the surface but also deep inside the substrate. It is possible to reduce the possibility of peeling of the inorganic protective film whose surface is modified.
Here, UV ozone treatment is a method in which a substrate is placed in an oxygen atmosphere and irradiated with ultraviolet rays to generate ozone, and the substrate surface is washed dry by the synergistic effect of ozone and ultraviolet rays. Means.
Specifically, the UV ozone treatment involves irradiating the base material with light from a low-pressure mercury lamp having an intense line spectrum at 185 nm and 254 nm in an atmosphere containing oxygen.
The treatment conditions are preferably those in which the intensity of irradiation light is 0.01 to 10 mW / cm ² , the oxygen concentration in the treatment atmosphere is 20 to 100% by volume, and the irradiation time is 30 seconds to 60 minutes.
Under such conditions, the epoxy resin base material is hardly modified to the inside.

  Furthermore, the present invention provides an electroluminescence display device, wherein the resin sheet is used as a substrate of an electroluminescence element.

  As described above, although the resin sheet according to the present invention is formed by laminating an inorganic protective film on an epoxy resin substrate, the inorganic protective film can hardly be peeled off.

Hereinafter, preferred embodiments of the present invention will be described.
As shown in FIG. 1, the resin sheet of this embodiment is in a state of being in close contact with the upper surface of the epoxy resin substrate 1 and the laminated surface of the epoxy resin substrate 1 (directly bonded without using other materials). A plasma polymerized film 2 obtained by plasma polymerization of a material containing carbon atoms, and an inorganic protective film 3 laminated in close contact with the upper surface of the plasma polymerized film 2. .
In this embodiment, the epoxy resin substrate 1 is a single-layer or multilayer sheet-like body made of an epoxy resin, and the epoxy resin substrate 1 is usually set to an average thickness of 100 to 800 μm. It has been done.

  Examples of the epoxy resin constituting the epoxy resin substrate 1 include bisphenol A type, bisphenol F type, bisphenol S type and bisphenol types such as water addition thereof, novolak types such as phenol novolac type and cresol novolac type, Low water absorption type such as triglycidyl isocyanurate type and hydantoin type, alicyclic type and aliphatic type, aromatic type such as naphthalene type, glycidyl ether type and biphenyl type, dicyclo type and ester type And ether ester types, and their modifications. These may be used alone or in combination. Among the various epoxy resins, it is preferable to use a bisphenol A type epoxy resin, an alicyclic epoxy resin, or a triglycidyl isocyanurate type from the viewpoint of discoloration prevention.

  As such an epoxy resin, generally, an epoxy equivalent having an epoxy equivalent of 100 to 1000 and a softening point of 120 ° C. or less is preferably used in view of physical properties such as flexibility and strength of the obtained resin sheet. Furthermore, from the point of obtaining an epoxy resin-containing liquid that is excellent in coating property, developability to a sheet shape, etc., a two-component mixed type that exhibits a liquid state at a temperature equal to or lower than the coating temperature, particularly at room temperature, can be preferably used.

Epoxy resins are conventionally known as curing agents, curing accelerators, and anti-aging agents, denaturing agents, surfactants, dyes, pigments, anti-discoloring agents, ultraviolet absorbers and the like that have been conventionally used as necessary. These various additives can be appropriately blended.
There is no limitation in particular also about the said hardening | curing agent, The 1 type (s) or 2 or more types of suitable hardening | curing agents according to an epoxy resin can be used. Examples include tetrahydrophthalic acid and methyltetrahydrophthalic acid, organic acid compounds such as hexahydrophthalic acid and methylhexahydrophthalic acid, ethylenediamine and propylenediamine, diethylenetriamine and triethylenetetramine, their amine adducts and Examples include amine compounds such as phenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

  In addition, amide compounds such as dicyandiamide and polyamide, hydrazide compounds such as dihydragit, methylimidazole, 2-ethyl-4-methylimidazole, ethylimidazole, isopropylimidazole, 2,4-dimethylimidazole, phenylimidazole, undecyl Examples of the curing agent include imidazole compounds such as imidazole, heptadecylimidazole, and 2-phenyl-4-methylimidazole.

Further, imidazolines such as methyl imidazoline, 2-ethyl-4-methyl imidazoline, ethyl imidazoline, isopropyl imidazoline, 2,4-dimethyl imidazoline, phenyl imidazoline, undecyl imidazoline, heptadecyl imidazoline, 2-phenyl-4-methyl imidazoline. Examples of the curing agent include compounds, phenolic compounds, urea compounds, and polysulfide compounds.
In addition, acid anhydride compounds and the like are also exemplified as the curing agent, and such an acid anhydride curing agent can be preferably used from the viewpoint of discoloration prevention. Examples include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, nadic anhydride, glutaric anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, Examples include methylhexahydrophthalic acid anhydride, methylnadic acid anhydride, dodecenyl succinic acid anhydride, dichlorosuccinic acid anhydride, benzophenone tetracarboxylic acid anhydride, and chlorendic acid anhydride.

  Particularly, an acid anhydride curing agent having a molecular weight of about 140 to about 200 and having a colorless or light yellow color such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, or methylhexahydrophthalic anhydride. Can be preferably used.

  The mixing ratio of the epoxy resin and the curing agent is such that when an acid anhydride curing agent is used as the curing agent, the acid anhydride equivalent is 0.5 to 1.5 equivalents per 1 equivalent of the epoxy group of the epoxy resin. It is preferable to mix | blend so that it may become, More preferably, 0.7-1.2 equivalent is good. When the acid anhydride is less than 0.5 equivalent, the hue after curing is poor, and when it exceeds 1.5 equivalent, the moisture resistance tends to decrease. In addition, also when using another hardening | curing agent individually or in combination of 2 or more types, the usage-amount can be based on said equivalent ratio.

  Examples of the curing accelerator include tertiary amines, imidazoles, quaternary ammonium salts, organometallic salts, phosphorus compounds, urea compounds, etc., particularly tertiary amines and imidazoles. It is preferable to use it. These can be used alone or in combination.

  It is preferable that the compounding quantity of the said hardening accelerator is 0.05-7.0 weight part with respect to 100 weight part of epoxy resins, More preferably, 0.2-3.0 weight part is good. When the blending amount of the curing accelerator is less than 0.05 parts by weight, a sufficient curing accelerating effect cannot be obtained, and when it exceeds 7.0 parts by weight, the cured body may be discolored.

Examples of the anti-aging agent include conventionally known compounds such as phenol compounds, amine compounds, organic sulfur compounds, and phosphine compounds.
Examples of the modifying agent include conventionally known ones such as glycols, silicones and alcohols.
The surfactant is added to smooth the surface of the sheet when the epoxy resin sheet is molded by casting the epoxy resin while being exposed to air. Examples of the surfactant include silicones, acrylics, and fluorines, and silicones are particularly preferable.

In the present invention, when the epoxy resin substrate 1 is formed by applying an epoxy resin on a support such as a glass plate or a stainless steel endless belt, the back surface of the epoxy resin substrate 1 is used. A resin layer (usually a hard coat layer 4 that is harder than the epoxy resin substrate 1) is formed on the surface opposite to the surface on which the inorganic protective film 3 is laminated. What is formed, that is, a layer formed by previously forming a hard coat layer 4 on a support and coating an epoxy resin on the hard coat layer 4 is preferable.
Examples of the material for forming the hard coat layer 4 include urethane resins, acrylic resins, polyester resins, and silicone resins.

  Among these resins, urethane resins are preferable, and urethane acrylate is particularly preferably used. For the formation of the hard coat layer 4, a blend of two or more kinds of suitable resins can be used.

  The thickness of the hard coat layer 4 is preferably 1 to 10 μm, and more preferably 2 to 5 μm. When the thickness is less than 1 μm, the releasability when the hard coat layer 4 is applied to a support such as a glass plate or a stainless steel endless belt is peeled off, and when it exceeds 10 μm, the smooth hard coat layer 4 is This is because it cannot be obtained.

The plasma polymerized film 2 is laminated in a state of being in close contact with the upper surface of the base material 1 by plasma polymerizing a material containing carbon atoms on the base material 1 to form a film on the base material 1.
As a method for forming a film by plasma polymerization, a gas pressure of 1 to 1400 Pa, preferably 10 to 300 Pa, a substrate temperature of 0 to 200 ° C., preferably 10 to 50 ° C., and glow discharge while passing through monomer components (usually And a method of using high-frequency power).
The plasma polymerized film 2 is usually set to an average thickness of 0.001 to 10 μm, preferably 0.005 to 1 μm. In the present specification, the average thickness of the film is measured by cross-sectional SEM observation.
Specifically, the measured values at five arbitrary points in an area of 1 cm ² are taken, and the average value is taken as the average thickness.
If the interface of the plasma polymerized film is unclear, the composition analysis of the cross section is performed with an EDX (energy dispersive X-ray analysis) apparatus attached to the SEM apparatus, and the measured value is obtained after clarifying the interface. be able to.

Examples of the plasma polymerized film 2 include amorphous carbon nitride, amorphous carbon, hetero five-membered ring organic compound plasma polymers such as furan and pyrrole, acrylic organic compound plasma polymers such as methyl methacrylate plasma polymer and acrylonitrile plasma polymer. Fluorine organic compound plasma polymer such as tetrafluoroethylene plasma polymer, Chlorine organic compound polymer such as dichloroethylene plasma polymer, Silicon organic compound such as tetraethoxy silicon plasma polymer, hexamethyldisilazane plasma polymer Any film of a plasma polymer or a film containing at least one of these can be employed. Among these, a film made of a plasma polymer of a hetero atom-containing compound, particularly an amorphous carbon nitride film is preferable.
According to such a film, the chemical bonding force with the inorganic substance is further increased by the heteroatoms present in the film, so that the adhesion with the inorganic protective film 3 is further improved.

When an amorphous carbon nitride film is employed as the plasma polymerized film 2, a plasma polymerization method that is a vapor phase growth method using a gas containing at least one of alkane, alkene, and alkyne and a gas containing nitrogen or ammonia as raw materials is used. Can be formed. For example, it can be formed by a plasma polymerization method using a mixed gas of methane gas and nitrogen gas as a raw material.
Since the amorphous carbon nitride film is a material mainly composed of carbon, the amorphous carbon nitride film has good wettability with the epoxy resin substrate 1 which is an organic substance and has high adhesion. Further, since the density of the film is high, van der Waalska working with the inorganic protective film 3 is strong, and high adhesion can be obtained with the inorganic protective film 3. Further, since the dense film is excellent in surface coverage, the adhesion is further improved.

  When the furan plasma polymerized film 2 is employed as the plasma polymerized film 2, it can be formed by a plasma polymerization method using vaporized furan as a raw material. In addition, at the time of film-forming of the polymer film 2 by these plasma polymerization methods, a base-material temperature can be performed at room temperature, and the damage to the epoxy resin base material 1 by a heat | fever at the time of film-forming can be prevented reliably.

The inorganic protective film 3 is formed on the plasma polymerized film 2 and is laminated in close contact with the upper surface of the plasma polymerized film 2.
The inorganic protective film 3 usually has an average thickness of 0.01 to 10 μm, preferably 0.02 to 2 μm per layer.
As the inorganic protective film 3, an inorganic film having a gas barrier property as compared with the epoxy resin as the base material 1 can be adopted. Specifically, nitrides such as silicon nitride (SiN _x ), aluminum nitride, and nitrided nitride, silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ , TiCO, etc.), etc. A material made of any of the following oxides, amorphous silicon, diamond-like carbon (DLC), or a material containing at least one of them can be used. These inorganic protective films 3 may be a single layer or a plurality of layers.

Further, these inorganic protective films 3 can be formed by a method such as a vacuum deposition method, a sputtering method, or a vapor phase growth method. Examples of the vapor deposition method include a plasma CVD (chemical vapor deposition) method, an ALE (atomic layer epitaxial growth) method, and a Cat (catalyst) -CVD method.
Among them, the plasma CVD method is preferable, and preferable conditions for forming a film by the plasma CVD method include a gas pressure of 1 to 1400 Pa, more preferably 10 to 300 Pa, and a substrate temperature of 0 to 200 ° C., more preferably 10 to 50. ℃. In addition, the conditions of the normally used high-frequency power are appropriately determined based on the device to be used.

When a silicon oxide film is used as the inorganic protective film 3, as an example, it can be formed by an RF sputtering method using a SiO ₂ target and using a mixed gas of argon and oxygen. In the case of using a silicon nitride film, for example, it can be formed by a plasma CVD method using silane gas, nitriding gas, and ammonia gas as raw materials.

In the present embodiment, the surface to be laminated, which is the surface on which the inorganic protective film of the epoxy resin substrate 1 is laminated, is preferably subjected to UV ozone treatment before lamination. Here, the UV ozone treatment means that the epoxy resin base material 1 is placed in an oxygen atmosphere and irradiated with ultraviolet rays to generate ozone, and the substrate surface is washed dry by the synergistic effect of ozone and ultraviolet rays. Means how to.
Resin in which the adhesiveness with the plasma polymerization film 2 is further improved and the possibility of peeling of the inorganic protective film 3 is further reduced while the original performance of the base material 1 is suppressed by the UV ozone treatment. Can be a sheet.
In other words, UV ozone treatment and plasma treatment are conventionally known as treatment methods for improving surface adhesion. However, when UV ozone treatment or plasma treatment is performed on a general plastic substrate, oxidation or the like deepens from the surface to the inside. In particular, when plasma treatment is performed by mixing an oxidizing gas such as oxygen in the discharge gas, ashing is further deepened from the surface of the base material, and the original flatness of the base material is also impaired. In this embodiment, since the epoxy resin has a characteristic excellent in oxidation resistance, even when exposed to ozone and ultraviolet rays, only the properties of the surface are modified without modification to the inside, Adhesive strength with the plasma polymerization film 2 becomes better while maintaining the original performance of the base material sufficiently.
From the viewpoint of sufficiently denaturing the surface while suppressing internal denaturation, the conditions for UV ozone treatment are based on the light of a low-pressure mercury lamp having a strong line spectrum at 185 nm and 254 nm in an atmosphere containing oxygen. It is preferable that the intensity of irradiated light is 0.01 to 10 mW / cm ² , the oxygen concentration in the processing atmosphere is 20 to 100% by volume, and the irradiation time is 30 seconds to 60 minutes.

In the present embodiment, instead of the UV ozone treatment, plasma treatment that exposes to plasma such as argon gas, oxygen gas, and nitrogen gas may be performed. Examples of the plasma treatment include a sputtering method using plasma, a plasma polymerization method, a plasma CVD method, and the like.
Before the lamination, the epoxy resin substrate 1 is exposed to plasma such as argon gas, oxygen gas, nitrogen gas, etc., so that only the surface is modified and the adhesion with the plasma polymerized film 2 is further improved.

Moreover, the epoxy resin substrate 1 in this embodiment preferably has a surface roughness of the surface to be laminated of 0.8 nm or less.
As an electronic device, in particular, a substrate for an electroluminescent element, high flatness is required for reasons of preventing element short circuit and ensuring fine workability. The formed plasma polymerization film 2 and inorganic protective film 3 can be made flat, and can be a resin sheet that can be sufficiently used as a substrate of an electronic device.
Here, the surface roughness of the substrate 1 is measured by AFM (Atomic Force Microscopy).

As a method for adjusting the surface roughness Ra of the surface to be laminated of the epoxy resin substrate 1 to 0.8 nm or less, for example, a resin layer (hard coat) that improves releasability on a support having a smooth surface such as a mirror surface While forming the layer 4), an epoxy resin coating solution is spread on the resin layer in a sheet form to form a film, and then peeled off from the support.
In this method, the coating liquid is developed by, for example, applying a fluid such as a roll coating method, a spin coating method, a wire bar coating method, an extrusion coating method, a curtain coating method, a spray coating method, or a dip coating method. An appropriate method that can be formed into a sheet shape can be employed. Surface smoothness can be remarkably enhanced by forming a free surface by such flow development. From the viewpoint of coating efficiency and production efficiency, roll coating method, wire bar coating method, curtain coating method, extrusion coating method and the like are preferable, especially an extrusion coating method in which a coating liquid is fluidly developed through a die. Is preferred.

In the present embodiment, it is preferable that the epoxy resin base material 1 has a surface to be laminated washed with an organic solvent before the plasma polymerization film 2 is laminated.
The general plastic base material 1 is easily eroded by chemicals such as organic solvents and acids / alkalis and cannot be cleaned sufficiently. The epoxy resin base material 1 is excellent in solvent resistance, so it is cleaned with an organic solvent. can do. Therefore, by removing dirt and dust on the surface of the base material 1, it can be excellent in adhesion to the inorganic protective film 3, and unevenness on the surface of the inorganic protective film 3 generated by the presence of dust or the like can be obtained. It can be prevented, and can be a resin sheet having flatness that can be sufficiently used as a substrate of an electronic device, in particular, an electronic device formed very thinly on the inorganic protective film 3.
In particular, in the case where the epoxy-based resin base material 1 has a release sheet for surface protection attached thereto via glue (adhesive), the glue cannot be completely removed even if the release sheet is peeled off. Since the paste inhibits the flatness of the surface, cleaning with an organic solvent is more preferable when such an epoxy resin substrate 1 is used.
The organic solvent includes cyclic ether organic solvents such as THF (tetrahydrofuran), chlorine organic solvents such as dichloromethane, chloroform, carbon tetrachloride, methylene chloride, and trichloroethylene, or one or more of these. Mixed solvents with other organic solvents can also be employed.
As a cleaning method, it is possible to employ a method of immersing in the organic solvent, optionally heating the organic solvent, and removing dirt or the like by ultrasonic cleaning or mechanical scrubbing.
Furthermore, it is preferable to perform the same cleaning with acetone, ethyl alcohol, and isopropyl alcohol after cleaning with these strong organic solvents.

In addition, after washing with an organic solvent, in order to remove dirt such as heavy metals, for example, ultrasonic washing with an organic alkaline detergent (for example, trade name “Semico Clean”, manufactured by Furuuchi Chemical Co., Ltd.) In order to remove completely, it is preferable to wash with running pure water and then dry.
As a drying method, for example, a method of heating and drying at 150 ° C. or more for 2 hours or more in an environment free from dust and particles using a clean oven can be employed.

Furthermore, in this embodiment, it is preferable that the said base material 1, the plasma polymerization film | membrane 2, and the inorganic protective film 3 are transparent.
If it is the resin sheet of such a structure, it can be used also as a board | substrate of an optical element and a light emitting element with which adoption of an opaque metal film, Si film, etc. is difficult.

  The resin sheet of the present embodiment is configured by laminating the inorganic protective film 3 on the epoxy resin base material 1 with the plasma polymerization film 2 interposed therebetween. When UV ozone treatment is performed on the laminated surface, the inorganic protective film 3 may be directly laminated without using the plasma polymerization film 2 as shown in FIG.

Hereinafter, the present invention will be described using examples and comparative examples.
<Preparation of epoxy resin substrate>
100 parts by weight of the liquid epoxy resin represented by the following chemical formula 1 and 80 parts by weight of the solid epoxy resin represented by the chemical formula 2 are mixed, stirred while heating at 90 ° C. and completely dissolved, and then allowed to cool to room temperature. The main agent was obtained. Next, 100 parts by weight of methylhexahydrophthalic anhydride represented by the chemical formula 3 and 12 parts by weight of the modifying agent represented by the chemical formula 4 were mixed, and the esterification reaction was performed by heating and stirring at 120 ° C. The mixture was cooled to room temperature and allowed to cool to room temperature, and 2 parts by weight of tetra-n-butylphosphonium o, o-diethyl phosphorodithioate represented by Chemical Formula 5 was stirred and mixed to obtain a curing agent. 120 parts by weight of the curing agent and 100 parts by weight of the main agent were mixed by stirring to prepare an epoxy resin-containing liquid.

Further, a 17 wt% toluene solution (including a photoinitiator) of urethane acrylate represented by the chemical formula 6 is cast-coated on a stainless steel endless belt having a running speed of 1.0 m / min, and air-dried to volatilize toluene. Then, it was cured using a UV curing device to form a urethane acrylate layer having a thickness of 2.0 μm. Subsequently, on the urethane acrylate layer having a running speed of 1.0 m / min, the prepared epoxy resin-containing liquid was cast and applied at a rate of 360 mm ³ / min, and heated at 150 ° C. using a heating device. It was cured by heating at 190 ° C. for 20 minutes to form an epoxy resin layer having a thickness of 400 μm. Next, the laminated body which consists of a urethane acrylate layer and an epoxy resin layer was peeled from the stainless steel endless belt, and the epoxy resin base material of the state by which the urethane acrylate layer (hard-coat layer) was laminated | stacked was prepared.

Example 1
The resin sheet of Example 1 was prepared using a sputtered silicon oxide film having gas barrier properties as the inorganic protective film and using an amorphous carbon nitride film formed by plasma polymerization as the plasma polymerization film.
Specifically, an amorphous carbon nitride film having a thickness of 0.1 μm was formed on the prepared epoxy resin substrate by plasma polymerization using methane gas and nitrogen gas as raw materials.
At this time, the pressure in the film forming chamber was 200 mTorr (1 Torr≈133 Pa), the methane gas flow rate was 10 sccm, the nitrogen gas flow rate was 5 sccm, the plasma input power was 20 W, and the substrate temperature was room temperature.
Next, a silicon oxide film as an inorganic protective film is formed on the amorphous carbon nitride film, and the pressure is set to 3 mTorr by an RF magnetron sputtering method using an Ar / O ₂ mixed gas (mixing ratio 7: 3) with an SiO ₂ target. The resin sheet of Example 1 was prepared by forming a film with a film thickness of 0.2 μm under the condition that the substrate temperature was room temperature.

Example 2
The resin sheet of Example 2 was prepared in the same manner as in Example 1 except that a silicon nitride film formed by a gas barrier plasma CVD method was used as the inorganic protective film.
Specifically, a mixed gas of SiH ₄ gas, NH ₃ gas, and N ₂ gas (mixing ratio 3: 3: 25) is used as a raw material on the amorphous carbon nitride film, and the pressure during film formation is set to 400 mTorr (1 Torr≈133 Pa). ), A silicon nitride film having a thickness of 0.2 μm was formed by plasma CVD with a plasma input power of 10 W and a substrate temperature of 100 ° C., and a resin sheet of Example 2 was prepared.

Example 3
The resin sheet of Example 3 was prepared using a silicon nitride film formed by a plasma CVD method having a gas barrier property as an inorganic protective film and a furan film formed by plasma polymerization as a plasma polymerization film.
Specifically, the prepared epoxy resin base material is vaporized furan, the pressure during film formation is 200 mTorr (1 Torr≈133 Pa), the plasma input power is 20 W, and the substrate temperature is room temperature. By a legal method, a 0.1 μm furan film was formed. Next, a silicon nitride film was formed on the furan film in the same manner as in Example 2 to prepare a resin sheet of Example 3.

Example 4
The resin sheet of Example 4 uses an epoxy-based resin base material in which the surface of the base material is treated with ozone generated by irradiating ultraviolet rays in an oxygen atmosphere (UV ozone treatment). It was prepared by laminating an inorganic protective film on the surface of the epoxy resin substrate using a silicon nitride film formed by CVD.
Specifically, first, the prepared epoxy resin base material was subjected to UV ozone treatment using a UV ozone cleaner (manufactured by Nippon Laser, NL-UV253) using a low-pressure mercury lamp as a light source.
In UV ozone treatment, an epoxy resin substrate is placed in an apparatus in which the internal air is replaced with oxygen (oxygen concentration: 100% by volume), irradiated with ultraviolet rays, and the generated ozone and irradiated ultraviolet rays are epoxy-based. A method of cleaning the resin base material surface was adopted. The intensity of ultraviolet rays on the substrate surface was 1 mW / cm ² and the irradiation time was 20 minutes.
After the UV ozone treatment, a silicon nitride film was formed on the epoxy base material in the same manner as in Example 2.

Comparative Example 1
A resin sheet of Comparative Example 1 was prepared in the same manner as in Example 1 except that no plasma polymerization film was formed.

Comparative Example 2
A resin sheet of Comparative Example 2 was prepared in the same manner as in Example 2 except that no plasma polymerization film was formed.

Test example 1
<Flatness>
Using the prepared resin sheets of Examples 1 to 4 and Comparative Examples 1 and 2, the surface morphology was observed with an AFM (atomic force microscope).
In the resin sheets of Examples 1 to 4, no protrusion having a height of several nm or more was observed. Also in the resin sheet of Comparative Example 1, no protrusion having a height of several nm or more was observed. However, in the resin sheet of Comparative Example 2, many protrusions of several tens of nm or more in which silicon nitride abnormally grew were observed with the segregated portion of the component of the epoxy resin base material as a nucleus.
When the inorganic protective film is grown by the plasma CVD method, if there is a segregated portion of the component on the base material, the film grows abnormally with this as a nucleus. In the resin sheets of Examples 2 and 3, In this case, since the plasma polymerized film formed on the epoxy resin substrate covers the segregated portion of the component on the substrate, a flat gas barrier inorganic protective film is formed on the plasma polymerized film. It is recognized that
In addition, in the resin sheet of Example 4, since the entire surface of the base material is activated by UV ozone treatment of the base material surface, the inorganic protective film formed by the plasma CVD method is partially abnormally grown. Is prevented.
As can be seen from this, when a very thin element such as an organic EL element is formed on a resin sheet, the protruding portion causes the leakage current of the element, but it is formed by a plasma polymerization method. A resin sheet in which an inorganic protective film is formed on an epoxy resin base material without forming a plasma polymerized film or without performing a UV ozone treatment step has many protrusions, and is used as a substrate for an organic EL element. It becomes inappropriate.

Test example 2
<Adhesion>
Using the resin sheets of Examples 1 to 4 and Comparative Examples 1 and 2, the adhesion of the inorganic protective film was tested by a tape peeling method. Each resin sheet was cut into a 2 mm square lattice with a cutter knife, and a Permacel Kapton tape (P-221) was applied thereto to peel the tape.
In the resin sheets of Examples 1 to 4, the silicon oxide film and the silicon nitride film did not peel from the plastic substrate. However, in Comparative Examples 1 and 2, the inorganic protective film peeled off in the region of 50% or more where the tape was peeled off.
Furthermore, when each resin tape was allowed to stand at 65 ° C. and a humidity of 95% RH for 1000 hours, the resin tapes of Examples 1 to 4 showed no abnormality such as peeling, whereas Comparative Examples 1 and 2 In this resin tape, peeling was observed at the interface between the inorganic protective film and the epoxy resin substrate.

  Resin sheets are used, for example, as substrates for electronic devices such as liquid crystal display devices and organic EL elements. However, in these electronic devices, deterioration of the elements rapidly progresses when moisture and oxygen from the substrate permeate, so that the gas barrier property is increased. It must be protected by an inorganic protective film such as a silicon oxide film or a silicon nitride film. However, as can be seen from the tape peeling test using the resin sheets of Comparative Examples 1 and 2 and the durability test at high temperature and high humidity, in the resin sheet in which the inorganic protective film is directly laminated on the substrate not subjected to UV ozone treatment, Since sufficient adhesion of the inorganic protective film cannot be realized, there is a possibility that the gas barrier property is lowered, which is not suitable as a substrate for an electronic device. On the other hand, a plasma-polymerized film such as an amorphous carbon nitride film between the epoxy resin substrate and a gas barrier inorganic protective film such as a silicon oxide film or silicon nitride as in the resin sheets of Examples 1 to 4 The resin sheet that is surface-modified by UV ozone treatment on the surface of the epoxy resin substrate is formed by adhesion between an inorganic protective film such as a silicon oxide film or a silicon nitride film and the epoxy resin substrate. It is highly suitable and is suitable as a substrate for electronic devices.

Example 5
After the protective sheet is peeled off from the prepared epoxy resin base material with a protective sheet laminated through glue, the epoxy resin base material is immersed in tetrahydrofuran (THF), hexane, acetone, and isopropyl alcohol in this order. For 10 minutes.
Thereafter, the substrate was immersed in a semi-clean glass substrate (manufactured by Furuuchi Chemical) and subjected to ultrasonic cleaning for 10 minutes, and then rinsed with pure water for 30 minutes or more. After pulling up the epoxy resin base material from pure water, it was kept in a clean oven at 150 ° C. for 2 hours and sufficiently dried.
After drying, an amorphous carbon nitride film having a thickness of 0.1 μm is formed on the surface of the substrate by plasma polymerization as a plasma polymerization film, and an amorphous silicon nitride film of 0.2 μm is formed by plasma CVD as an inorganic protective film. A resin sheet of Example 5 was prepared by depositing on a carbon nitride film.
In the formation of the amorphous carbon nitride film, the pressure in the deposition chamber was 200 mTorr (1 Torr≈133 Pa), the methane gas flow rate was 10 sccm, the nitrogen gas flow rate was 5 sccm, the plasma input power was 20 W, and the substrate temperature was room temperature.
In forming a silicon nitride film, plasma CVD using a mixed gas of SiH ₄ gas, NH ₃ gas, and N ₂ gas (mixing ratio 3: 3: 25) as a raw material is performed in a consistent vacuum process without exposure to the atmosphere. The law was adopted. Further, the pressure during film formation was 400 mTorr (1 Torr≈133 Pa), the plasma input power was 10 W, and the substrate temperature was 100 ° C.

Example 6
A resin sheet of Example 6 was prepared in the same manner as in Example 5 except that trichloroethylene was used instead of tetrahydrofuran (THF) and hexane in Example 5.

Example 7
A resin sheet of Example 7 was prepared in the same manner as Example 5 except that tetrahydrofuran and hexane were not used and ethyl alcohol was used instead of isopropyl alcohol.

Test example 3
<Flatness>
Using the resin sheets of Examples 5, 6, and 7, the surface morphology was observed with an AFM (atomic force microscope). In a 5 μm square region, the number of protrusions due to foreign matters having a height of several nm or more was counted. The number of protrusions was zero in Examples 5 and 6. In contrast, in Example 7, several tens and several large residues with a height of several tens of nm were observed.
When using an epoxy resin base material with a protective sheet laminated, in order to completely remove the dirt after the protective sheet is peeled off, a cyclic ether organic solvent or a chlorinated organic solvent such as tetrahydrofuran or trichloroethylene with strong degreasing power is used. It is recognized that it needs to be used. Epoxy resin base materials are excellent in resistance to these organic solvents, and it is recognized that a flat and clean surface can be obtained without damaging the surface by washing with the organic solvent.

Test example 4
<Adhesion>
The adhesion of the inorganic protective film in the resin sheets of Examples 5, 6, and 7 was tested by a tape peeling method.
Each resin sheet was cut into 2 mm square grids with a cutter knife, and Permacel Kapton tape (P-221) was applied thereto, and the tape was peeled off.
In any of Examples 5, 6, and 7, the inorganic protective film did not peel from the epoxy resin substrate. In Example 7, although projections of foreign matters were observed on the surface due to contamination of the epoxy resin substrate, the amorphous carbon nitride film formed by the plasma polymerization method worked as an adhesion layer, and the inorganic protective film adhered. The power was sufficient.
Furthermore, when each resin sheet was allowed to stand at 65 ° C. and a humidity of 95% RH for 1000 hours, the resin sheets of Examples 5 and 6 showed no abnormality such as peeling, whereas the resin of Example 7 In the sheet, slight peeling was observed. In the resin sheet of Example 7, protrusions of several tens of nanometers or more were observed from the AFM observation, and moisture penetrated and peeled from the portion that was not completely covered with the silicon nitride film formed thereon. Is recognized as occurring. Since the resin sheets of Examples 5 and 6 are sufficiently washed so that there are no foreign substances on the epoxy resin substrate, a stable resin sheet that maintains sufficient gas barrier properties even under severe conditions such as high temperature and high humidity It is recognized that

Sectional drawing which shows the resin sheet of one Embodiment. Sectional drawing which shows the resin sheet of other embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Epoxy resin base material, 2 ... Plasma polymerization film, 3 ... Inorganic protective film

Claims (8)

  An epoxy resin base material, a plasma polymerized film obtained by plasma polymerizing a material containing carbon atoms, which is laminated in close contact with the epoxy resin base material, and a plasma polymerized film laminated in close contact with the plasma polymerized film. A resin sheet comprising an inorganic protective film.   The resin sheet according to claim 1, wherein a surface to be laminated of the epoxy base material is subjected to UV ozone treatment.   The plasma polymerized film contains at least one selected from amorphous carbon nitride, amorphous carbon, hetero five-membered ring organic compound plasma polymer, acrylic organic compound plasma polymer, and silicon organic compound plasma polymer. The resin sheet according to claim 1 or 2.   The plasma polymerized film contains amorphous carbon nitride, and the amorphous carbon nitride is formed by a plasma polymerization reaction between at least one gas selected from alkanes, alkenes and alkynes, and a gas containing nitrogen or ammonia. The resin sheet according to claim 3.   An epoxy resin base material and an inorganic protective film laminated in close contact with the epoxy resin base material, and a surface to be laminated of the epoxy resin base material is UV ozone treated Resin sheet.   The resin sheet according to any one of claims 1 to 5, wherein the inorganic protective film contains at least one of an inorganic oxide and an inorganic nitride.   The laminated surface of the epoxy resin base material is washed with an organic solvent containing either a cyclic ether organic solvent or a chlorinated organic solvent, according to any one of claims 1 to 6. Resin sheet.   An electroluminescence display device, wherein the resin sheet according to any one of claims 1 to 7 is used as a substrate of an electroluminescence element.

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