JP2008050235A - Clay thin film, its manufacturing method and clay thin film laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a clay thin film which has a very low coefficient of linear expansion in a high temperature range and is excellent in heat resistance, dimensional stability, water resistance, transparency and gas barrier property, and to provide a method for manufacturing the clay thin film, and a clay thin film laminate. <P>SOLUTION: The clay thin film consists of a combined material of clay consisting of clay particles, in each of which a hydrophobic cationic substance is introduced into the space between layers, with an epoxy resin having bisaryl fluorene as a basic skeleton. Each of the clay particles is oriented and has a layered structure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat-resistant clay thin film, a method for producing the same, and a clay thin film laminate. In particular, clay particles introduced with a specific cationic substance are highly oriented and have a structure in which many layers are laminated. Excellent in dimensional stability under high temperature environment and gas barrier property under high temperature and high humidity. The present invention relates to a clay thin film having flexibility, a method for producing the same, and a clay thin film laminate.

  The display is rapidly changing from a conventional cathode ray tube system to a liquid crystal system (LCD) in terms of mobility and space saving. In addition, self-luminous devices have been developed as next-generation displays, and organic EL devices that are excellent in terms of brightness, vividness, and power consumption have begun to be produced. These are much better in terms of mobility and space saving than conventional cathode ray tube systems, but they are relatively heavy and break because glass is used as the substrate. It also has drawbacks.

  In order to solve these problems, a film substrate (referred to as a “placel”) is used in some liquid crystal type devices. However, there is no film substrate that can be used for the TFT driving method that can handle moving images, which is currently mainstream. The reason is that, in the case of the TFT driving type, a film substrate that can withstand the temperature for forming the TFT circuit and is highly transparent is required.

The clay thin film has excellent flexibility and has a structure in which clay particles are densely oriented in layers, so it is a material with excellent gas barrier properties, and excellent heat resistance and flame resistance. Yes (see Patent Document 1). However, there are problems with water resistance and transparency.
JP 2005-104133 A

  As described above, in order to use as a film substrate for liquid crystal or organic EL display, a film excellent in heat resistance and dimensional stability as well as water resistance and transparency is required. Accordingly, an object of the present invention is to provide a clay thin film excellent in heat resistance, dimensional stability, water resistance, transparency and gas barrier properties, and a method for producing the same. Another object of the present invention is to provide a clay thin film and a clay thin film laminate that can be used as film substrates for various products such as liquid crystals and organic EL displays.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that conventional plastics can be obtained by using clay organized with a hydrophobic cationic substance and an epoxy resin having bisarylfluorene as a basic skeleton. It was found that a low dimensional change rate at a high temperature, which was impossible with a film, can be realized, and a clay thin film excellent in heat resistance, dimensional stability, water resistance, transparency and gas barrier properties can be obtained. It came to be completed.

  That is, the clay thin film of the present invention comprises a composite of clay composed of clay particles introduced with a cationic substance having hydrophobicity between layers and an epoxy resin having bisarylfluorene as a basic skeleton, and the clay particles are oriented. And having a laminated structure. In the present invention, the blending ratio of the clay and the epoxy resin is preferably 50:50 to 99: 1. Further, it is preferable to use an acid anhydride curing agent as the curing agent for the epoxy resin.

  In the clay thin film of the present invention, the cationic substance having hydrophobicity is at least one of quaternary phosphonium, pyridinium, and imidazolium containing a linear or branched alkyl group having 1 to 18 carbon atoms. Preferably. The cationic substance preferably contains a phenyl group.

  As the clay, synthetic clay is preferable.

The clay thin film of the present invention has a linear expansion coefficient in the range of 150 to 350 ° C. of 40 × 10 ⁻⁶ / ° C. or less and has flexibility. In the present invention, the clay thin film has a total light transmittance of 85% or more, a haze of 2.5% or less, gas barrier performance, and oxygen permeability at 40 ° C./90%. It is preferably 30 cc / m ² · day · atm or less, and the water vapor permeability at 40 ° C./90% is preferably 5.0 g / m ² · day or less.

  The clay thin film laminate of the present invention is characterized in that at least one of an inorganic thin film or an organic thin film is laminated in a single layer or a plurality of layers on one side or both sides of the clay thin film of the present invention.

  The method for producing a clay thin film according to the present invention is a method for producing the above clay thin film, wherein a clay and a resin comprising clay particles into which a cationic substance having hydrophobicity is introduced between clay particle layers are contained in a solvent. The clay paint obtained by dispersing is applied to a substrate, dried, and peeled from the substrate.

  Next, the clay thin film of the present invention will be described in detail. The clay thin film of the present invention is composed of a composite of clay (organized clay) composed of clay particles into which a cationic substance having hydrophobicity is introduced between layers, and an epoxy resin having bisarylfluorene as a basic skeleton. . In the present invention, clay refers to a clay mineral having a layered structure in which unit crystal layers are stacked on each other, and those that swell and cleave in a solvent are preferably used. In the present invention, natural clay or synthetic clay can be used as clay. In the present invention, it is more preferable to use synthetic clay because high transparency is obtained. Specific examples of clay minerals that swell and cleave in solvents include smectites such as montmorillonite, hectorite, stevensite, saponite, and beidellite, or kaolinite, dickite, nacrite, halosite antigolite, chrysotile, and white cloud. Mother, talc, vermiculite, phlogopite, etc. can be mentioned. Among these, smectite, kaolinite, saponite, and mica are preferable in terms of dispersibility and swelling.

  The shape of the clay particles is scaly. Typically, in a smectite, one clay particle has a scaly shape having a thickness of about 1 nm and an aspect ratio of 20 to several hundred to several thousand. In the clay thin film of the present invention, such scaly clay particles are overlapped in several layers, whereby the gas passage route becomes longer, and as a result, the gas barrier property is improved.

  In these clays, a cationic substance having hydrophobicity is introduced between the layers of the clay particles (organization treatment). As the cationic substance having hydrophobicity, a linear or branched chain having 1 to 18 carbon atoms is used. Those containing at least one of quaternary phosphonium, pyridinium and imidazolium containing the above alkyl group are preferred. More preferably, it has a linear or branched alkyl group having 10 to 18 carbon atoms, more preferably 12 to 16 carbon atoms. The greater the number of carbon atoms in the alkyl group, the easier the clay into which the cationic material has been introduced will swell and disperse in the solvent. However, the larger the number of carbon atoms in the alkyl group, the lower the heat resistance. Therefore, those having an alkyl group in the above range are preferred.

  From the viewpoint of heat resistance, those containing a phenyl group are preferred. By containing a phenyl group, the decomposition | disassembly with respect to a heat | fever is suppressed rather than the thing which does not contain a phenyl group, and heat resistance improves. However, combined use with an alkyl group is preferred from the viewpoint of the swelling and dispersibility of the clay.

  In the present invention, an epoxy resin having a bisarylfluorene skeleton is added to the organized clay to form a composite. An epoxy resin having a bisarylfluorene skeleton can provide a cured product that is excellent in transparency, heat resistance, and mechanical strength, and that is not colored by heating. Moreover, you may contain other resins, such as an epoxy resin which does not have a bisaryl fluorene skeleton, an acrylic resin, a silicone resin, a fluororesin, a polyimide resin, and a phenol resin as needed.

  When an epoxy resin is used as the resin, examples of the additive for obtaining a cured product of the epoxy resin include other materials such as a curing agent, a curing accelerator, a coupling agent, a reactive diluent, and an antioxidant. .

  Examples of the curing agent include an amine curing agent, a phenol resin curing agent, a ketimine curing agent, an imidazole curing agent, and an acid anhydride curing agent. In the present invention, it is preferable to use an acid anhydride curing agent from the viewpoint of heat resistance. The acid anhydride curing agent is not particularly limited as long as it is a compound having an acid anhydride structure. Examples of such acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, trimellitic anhydride, benzophenone tetracarboxylic anhydride, etc. Can be given. These acid anhydride curing agents may be appropriately selected according to various necessary characteristics. For example, if the cured product requires transparency, use a hydrogenated double bond in the alicyclic skeleton such as methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, hydrogenated methylnadic anhydride, etc. Just choose.

  The curing accelerator is not particularly limited, but imidazoles such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, phenol salts, phenol novolac salts, Examples thereof include amines such as carbonate and formate and derivatives thereof, and organophosphines such as ethylphosphine and triphenylphosphine.

  The reactive diluent is used for adjusting the viscosity and is not particularly limited, and examples thereof include low-viscosity epoxy compounds such as diglycidyl ether, butanediol diglycidyl ether, diglycidyl aniline. , Cyclohexanedimethanol diglycidyl ether, alkylene diglycidyl ether, vinylcyclohexene dioxide, and the like. These reactive diluents may be used alone or in combination of two or more.

  The antioxidant is not particularly limited, and examples thereof include phenyl phosphites, phenols, sulfur-based, phosphorus-based and the like.

  The coupling agent can be used to improve the adhesion of the interface between clay and resin and improve the strength of the clay thin film. When an epoxy resin is used as the resin, a silane compound having a functional group reactive with the epoxy resin is preferably used. Specifically, silane coupling agents having an epoxy group such as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane Silane coupling agents having an amino group such as 3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, etc. It is done.

  In the clay thin film of the present invention, the blending ratio (polymerization ratio) of clay composed of clay particles into which a cationic substance is introduced, that is, an organized clay and an epoxy resin having a bisarylfluorene skeleton is 50:50 to 99: 1. The blending ratio is preferably 60:40 to 97: 3, more preferably 80:20 to 97: 3. If the amount of the resin increases, the heat resistance of the clay thin film is controlled by a resin having a lower heat resistance than clay, which is not preferable.

The clay thin film of the present invention has a linear expansion coefficient in the range of 150 to 350 ° C. of 40 × 10 ⁻⁶ / ° C. or less and has flexibility. By setting the blending ratio of clay and resin to 50:50 to 99: 1, a low linear expansion coefficient of 40 × 10 ⁻⁶ / ° C. or less can be obtained at a high temperature range up to 350 ° C. that cannot be obtained with a normal resin film. It can be realized and has flexibility by adding a resin.

  In the clay thin film of the present invention, by using synthetic clay as the clay, transparency can be improved and the total light transmittance can be 85% or more. In addition, by adjusting the swelling and dispersibility of the clay particles and smoothing the surface during film formation, the haze (cloudiness) can be reduced to 2.5% or less.

  The clay thin film of the present invention can be used alone as a self-supporting film, but in order to obtain higher gas barrier properties, chemical resistance, surface smoothness, hard coat properties, and high strength, one side or both sides of the clay thin film Further, it is possible to form a clay thin film laminate by laminating at least one of an inorganic thin film and an organic thin film as a single layer or a plurality of layers. Although the film | membrane type of the inorganic thin film and organic thin film to be laminated | stacked is not specifically limited, What is necessary is just to select the optimal thing according to a use. For example, by forming silicon oxide, silicon oxynitride, or silicon nitride by sputtering or plasma CVD, high gas barrier properties and chemical resistance can be imparted. Furthermore, by applying an organic polymer, the surface can have flatness and hard coat properties. By laminating a surface coat composed of these inorganic thin films and organic thin films, it is possible to impart characteristics that cannot be obtained with a clay thin film alone.

  Next, the manufacturing method of the clay thin film of this invention is demonstrated. First, clay is treated with a cationic substance having hydrophobicity to produce an organized clay. The treatment with the hydrophobic cationic substance is performed, for example, by dispersing the hydrophobic cationic substance in water, adding clay to the dispersion and swelling it, then performing solid-liquid separation treatment, and adding water. The solid-liquid separation process can be repeated until foaming disappears, and then dried to completely remove moisture. Thereby, the hydrophilic exchangeable cation contained in the clay is exchanged by the cation having hydrophobicity, and the organized clay is produced.

Next, the above-mentioned organized clay and resin are dispersed in a solvent at a predetermined blending ratio to prepare a clay paint. Dispersion can be carried out by a general dispersion method. However, in order to disperse clay particles uniformly and more evenly in a solvent, it is necessary to give a high shear force or raise the temperature of the solvent. preferable. The clay paint may be added with general additives such as an antioxidant, a surfactant, an ultraviolet absorber, an antistatic agent, a pigment, and a leveling agent within the range not impairing the object of the present invention. Good The resulting clay paint is then applied onto the substrate. Although it does not specifically limit as a base material, A general organic polymer film, metal foil, a metal plate, etc. can be used. As for the surface property of the applied film, since the surface property of the substrate is transferred as it is in the case of the substrate side, the substrate having a flat surface is preferable. When a polymer film is used as the substrate, only a certain temperature can be applied during drying or curing. This is because if a clay paint is applied on a polymer film and exposed to a high temperature, for example, 200 ° C. without peeling off, the substrate polymer film is deformed and cannot serve as a substrate. It is. Therefore, when drying at a high temperature or applying a high temperature is necessary, a metal foil, a metal plate, a long metal roll, or the like may be used as the base material. Thereby, high temperature processing can be performed without worrying about the heat resistance of the substrate. Further, the surface of the metal foil, metal plate, and metal long roll is preferably flat with a mirror finish or the like in order to affect the surface properties of the applied film. The method of applying the clay paint to the substrate is not particularly limited, and various blade coaters, roll coaters, air knife coaters, bar coaters, gravure coaters, die coaters, curtain coaters and the like are used.

  After applying clay paint on the substrate, drying, peeling and obtaining a clay thin film film, or by applying pressure treatment, heat pressure treatment between the above steps, the surface is flattened, the film is dense Can be made. For example, the surface can be flattened by performing a thermal calendar process.

  Although the thickness of the clay thin film of this invention is not specifically limited, The range of 10-300 micrometers is preferable. More preferably, it is 50-200 micrometers, and when it is thinner than 10 micrometers, there is no intensity | strength and it does not materialize as a self-supporting film. If it is thicker than 300 μm, the load in the drying process is increased, and the productivity is lowered, which is not preferable.

  In the above method, the clay having a layered structure is further loosened, and a clay paint in which the resin added between the layers enters is prepared, and it is applied and dried to form a film. The clay particles can be highly oriented in the horizontal direction of the clay thin film, and a clay thin film having a structure in which clay particles are densely laminated can be obtained. Therefore, a clay thin film with improved gas barrier properties can be produced by the method for producing a clay thin film of the present invention.

  Since the clay thin film and the clay thin film laminate of the present invention have the above-described configuration, a low dimensional change rate at a high temperature that could not be realized by a conventional plastic film can be realized, and heat resistance, dimensional stability, water resistance, It has excellent transparency and gas barrier properties. In addition, since the method for producing a clay thin film of the present invention has the above-described configuration, the resulting clay thin film has a structure in which clay particles are highly oriented in the horizontal direction and clay particles are densely laminated. The gas barrier property is improved.

  Therefore, the clay thin film and the clay thin film laminate of the present invention can be used for many products due to various properties thereof. For example, electronic paper substrate, electronic device sealing film, lens film, light guide plate film, prism film, retardation plate / polarizing plate film, viewing angle correction film, PDP film, LED film, organic EL film Substrates, optical communication members, touch panel films, various functional film substrates, electronic device films with a transparent structure, video discs, CDs, CD-Rs, CD-RWs, DVDs, MOs, MDs, phases It can be used for films for optical recording media including change disks and optical cards, sealing films for fuel cells, films for solar cells, packaging-related films, electronic device substrate films, flexible printed boards, printed boards and the like. In addition to the above, it can be used as a heat resistant film in a high temperature range that cannot be used with conventional resin films.

  Hereinafter, the best mode for carrying out the present invention will be described based on examples, but the present invention is not limited to these examples.

(Organization of clay)
After 5 g of octadecyltriphenylphosphonium bromide was dispersed in 50 g of pure water, 5 g of synthetic smectite (Smecton SA, manufactured by Kunimine Kogyo Co., Ltd.) was added and sufficiently dispersed and swollen. The obtained dispersion was subjected to solid-liquid separation with a centrifuge to remove the liquid, and then 50 g of pure water was further added to perform dispersion and solid-liquid separation. This dispersion / solid-liquid separation was repeated until no foaming occurred, and then water was completely removed by a dryer. As a result, the hydrophilic exchangeable cation and octadecyltriphenylphosphonium ion contained in the clay were exchanged, and a water-resistant organoclay having swelling properties with respect to toluene, which is a nonpolar solvent, was obtained.

(Formation of clay thin film)
The organoclay obtained as described above is pulverized, 10 g of the organoclay is dispersed and swollen in 100 g of toluene, and the bisarylfluorene skeleton is so formed that the ratio of the organoclay to the resin is 8: 2. Epoxy resin having 2.5 g (EX1020, manufactured by Nagase Sangyo Co., Ltd.) and 2.0 g of acid anhydride curing agent (HNA-100, manufactured by Shin Nippon Rika Co., Ltd.) were added and dispersed. The obtained clay paint was applied onto a PET film that had been treated with an applicator to form a film. Thereafter, it was put into a dryer at 100 ° C. to remove the solvent. Next, the clay thin film was peeled from the PET film, and the epoxy resin was cured by curing at 170 ° C./2 hours. As a result, a transparent and flexible clay thin film having a thickness of 80 μm was obtained.

  A clay thin film having a thickness of 80 μm was obtained in the same manner as in Example 1 except that the ratio of the organized clay to the resin was 5: 5.

  A clay thin film having a thickness of 80 μm was obtained in the same manner as in Example 1 except that the ratio of the organized clay to the resin was 9.5: 0.5.

  A clay thin film having a thickness of 80 μm was obtained in the same manner as in Example 1 except that octadecylphenylimidazolium bromide was used during the organic treatment.

  UV curing urethane acrylate (purple light UV7600B, manufactured by Nippon Synthetic Chemical Co., Ltd.), which is a hard coat material, was applied to both sides of the clay thin film produced in Example 1 using a bar coater and cured by ultraviolet irradiation. A hard coat layer of 1 μm was laminated on both sides to obtain a clay thin film laminate.

A SiO _x film having a thickness of 60 nm, which is an inorganic layer, was laminated on both the front and back surfaces of the clay thin film produced in Example 1 by reactive sputtering to obtain a clay thin film laminate.

[Comparative Example 1]
A clay thin film was prepared in the same manner as in Example 1 except that synthetic smectite (Smecton SA, manufactured by Kunimine Kogyo Co., Ltd.) not subjected to organic treatment was used. However, since the clay particles settled without the clay being uniformly dispersed and swollen in toluene, the film could not be formed.

[Comparative Example 2]
A clay thin film having a thickness of 80 μm was obtained in the same manner as in Example 1 except that an epoxy resin having no bisarylfluorene skeleton (Kesimir E-622, manufactured by Chemtech) was used as the resin.

(Evaluation)
The clay thin film films produced in Examples 1 to 6 and Comparative Example 2 were evaluated as follows.
Linear expansion coefficient:
Using a thermal analyzer TMA (Thermomechanical Analyzer, 8310, manufactured by Rigaku Corporation), a linear expansion coefficient was calculated by measuring at a heating rate of 5 ° C./min from a load of 1 g to room temperature to 350 ° C. by a tensile load method. .
Total light transmittance and haze:
It measured using the haze meter (Haze Meter NDH2000, the Nippon Denshoku make).

Gas barrier properties (oxygen permeability, water vapor permeability):
Using a differential pressure type gas / vapor vapor transmission measuring device (GTR-30XATS, manufactured by GTR Tech Co., Ltd.), the oxygen and water vapor transmission rates at 40 ° C./90% were measured.
Appearance after heating at 200 ° C./30 min:
The sample was placed in a dryer set at a temperature of 200 ° C., heat-treated for 30 minutes, and then taken out to check visually whether or not the appearance (dimensions, color, transparency, etc.) had changed. Table 1 shows the results of the examples and Table 2 shows the results of the comparative examples.

  As is clear from the above table, the clay thin film and the viscous thin film laminate of the present invention have a very low linear expansion coefficient in a high temperature range (150 to 350 ° C.), achieving a level that cannot be achieved with other polymer films. In addition, it was flexible and had good transparency and gas barrier properties.

Claims (13)

  It is composed of a composite of clay composed of clay particles introduced with a cationic substance having hydrophobicity between layers and an epoxy resin having bisarylfluorene as a basic skeleton, and the clay particles are oriented and have a laminated structure. Characteristic clay thin film.   The clay thin film according to claim 1, wherein a blending ratio of the clay and the epoxy resin is 50:50 to 99: 1.   The clay thin film according to claim 1 or 2, wherein an acid anhydride curing agent is used as a curing agent for the epoxy resin.   2. The cationic substance according to claim 1, wherein the cationic substance contains at least one of quaternary phosphonium, pyridinium, and imidazolium containing a linear or branched alkyl group having 1 to 18 carbon atoms. The clay thin film described.   The clay thin film according to claim 4, wherein the cationic substance contains a phenyl group.   The clay thin film according to claim 1, wherein the clay is a synthetic clay. The linear expansion coefficient in the range of 150-350 degreeC is 40 * 10 < ^-6 > / degrees C or less, and has a softness | flexibility, The clay thin film of any one of Claims 1-6 characterized by the above-mentioned. .   The clay thin film according to any one of claims 1 to 7, wherein the total light transmittance is 85% or more.   The clay thin film according to any one of claims 1 to 8, wherein the haze is 2.5% or less. The clay thin film according to any one of claims 1 to 9, which has a gas barrier performance and has an oxygen permeability at 40 ° C / 90% of 30 cc / m ² · day · atm or less. The clay thin film according to any one of claims 1 to 10, which has gas barrier performance and has a water vapor permeability at 40 ° C / 90% of 5.0 g / m ² · day or less.   A clay thin film laminate, wherein at least one of an inorganic thin film or an organic thin film is laminated in a single layer or a plurality of layers on one side or both sides of the clay thin film according to any one of claims 1 to 11. body.   Applying a clay paint obtained by dispersing clay and resin made of clay particles with a hydrophobic cationic substance between clay particle layers in a solvent to a substrate, drying, and peeling from the substrate The method for producing a clay thin film according to claim 1.