JP2000062074A - Conductive plastic laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve bending resistance and to prevent the generation of conductive peeling and cracks by defining the hardness of a cured coat layer in a specified range. SOLUTION: A conductive plastic laminate is constituted from a plastic base material layer, a conductive layer, and a cured coat layer. As required, an optional constitutional layer such as a gas barrier layer is added. By placing the cured coat layer between the plastic base material layer and the conductive layer, the adhesion of the conductive layer is improved. The physical properties of the cured coat layer in addition to such layer constitution are important for the plastic laminate, the hardness of the cured coat layer is made 0.05-0.20 GP. Also, the modulus of elasticity of the cured coat layer is made 1.0-4.0 GP. By meeting the features of these properties, since cracks are generated in the conductive layer, and the deterioration of electric resistance is eliminated even when the conductive plastic laminate is deflected, the conductive plastic laminate of high bending resistance can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive plastic laminate suitably used for substrates of liquid crystal display devices, touch panels, solar cell conversion elements and the like.

[0002]

2. Description of the Related Art With the rapid progress of electronics technology, the field of optoelectronics such as liquid crystal display devices, touch panels, and solar cell conversion elements is expanding. In general, optoelectronic devices are used for various purposes by forming the device on a glass substrate having a transparent conductive layer. However, glass has a large weight, and when incorporated in a portable device, there is a problem that the weight of the device becomes large due to the large specific gravity of the glass. Therefore, weight reduction is strongly desired, and polyarylate, polyether sulfone, polycarbonate, etc., which are relatively excellent in strength, transparency, heat resistance, etc., are being adopted as plastic sheet substrates instead of glass substrates.

In the field of optoelectronic devices,
In particular, since high optical properties, gas barrier properties, electrical conductivity, mechanical strength, etc. are required, in practice, a plurality of layers or films having respective functions are laminated on a substrate. Japanese Patent No. 5308 proposes a conductive plastic laminate in which a cured film is provided on both surfaces of a plastic sheet, a conductive layer is provided on one surface, and a gas barrier layer made of a metal oxide is provided on the other surface.

[0004]

However, in the above-mentioned conductive plastic laminate, in addition to the problem due to the properties of the base sheet and the conductive layer, heating due to the difference in the properties of each layer and the problem of adhesion, etc. There is a problem that cracks are likely to occur. Also, although it is a plastic sheet substrate that is useful as a glass substitute substrate, in order to increase its utility value,
Not only must it be lightweight, but it must also have flexibility. That is, when the substrate is bent (bent) with a certain curvature, the conductive layer is not cracked and it is necessary to maintain electric conductivity. However, the conventional conductive plastic sheet substrate has a problem that its bending resistance is insufficient.

[0005]

In order to solve the above problems, the inventors of the present invention have earnestly studied a conductive plastic laminate having sufficient bending resistance as a substrate for liquid crystal device, touch panel, solar cell and the like. As a result, the present invention has been completed by focusing on the fact that the cured film interposed as a layer structure between the plastic substrate layer and the conductive layer plays an extremely important role in the bending resistance of the conductive plastic laminate. Came to. That is, the present invention is a plastic laminate having a cured coating layer between a plastic substrate layer and a conductive layer, wherein the hardness of the cured coating layer is 0.05 or more and 0.20.
It exists in the electroconductive plastics laminated body characterized by being GP or less.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The conductive plastic laminate of the present invention will be described in more detail below. (Plastic Base Material Layer) The plastic base material layer constitutes the base material layer of the plastic laminate of the present invention. The plastic raw material that is the base material layer is not particularly limited as long as it is used as a film or sheet, ethylene,
Polyolefin (PO) resins such as homopolymers or copolymers of propylene and butene, amorphous polyolefin resins (APO) such as cyclic polyolefins, polyethylene terephthalate (PET), polyethylene-2,6-naphthalate (PEN) Polyester resin such as nylon, nylon 6, nylon 12, polyamide such as copolymer nylon (P
A) type resins, polyvinyl alcohol (PVA) resins, polyvinyl alcohol type resins such as ethylene-vinyl alcohol copolymer (EVOH), polyimide (PI) resins,
Polyetherimide (PEI) resin, polysulfone (P
S) resin, polyether sulfone (PES) resin, polyamide imide (PAI) resin, polyether ether ketone (PEEK) resin, polycarbonate (PC) resin, polyvinyl butyral (PVB) resin, polyarylate (PAR) resin, ethylene -Tetrafluoroethylene copolymer (ETFE), trifluoroethylene chloride (PCTF)
E), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), vinylidene fluoride (P)
VDF), vinyl fluoride (PVF), fluorine resin such as perfluoroethylene-perfluoropropylene-perfluorovinyl ether terpolymer (EPE), (meth)
Examples thereof include acrylate resins.

Among the above, APO, PET and PE are used in view of optical properties such as polarization and transparency, strength and heat resistance.
Thermoplastic resins such as S, PAI, PC, PAR, etc., or sulfur-containing (meth) acrylate resins described in JP-A-62-195357 and JP-A-62-1255.
A photo-curable resin represented by the alicyclic skeleton (meth) acrylate resin described in JP-A-08, etc. is particularly preferable.

The above-mentioned thickness of the base material layer has a desired mechanical strength,
The thickness is usually 5 to 500 μm, although it can be appropriately selected depending on flexibility, transparency, use, or the like. The base material layer may be stretched or may be a laminate of a plurality of plastic layers. (Cured film layer) As the cured film in the present invention, any organic compound-based cured film may be used without particular limitation, but is formed of a hard coating agent, an anchor coating agent (primer coating agent), or the like. Is. As a specific example thereof, as the hard coat agent, those having acrylates such as polyurethane acrylate and epoxy acrylate or polyfunctional acrylates, a photopolymerization initiator, and an organic solvent as main components can be used. Examples of the anchor coating agent include known anchor coating agents such as isocyanate type, polyurethane type, polyester type, polyethyleneimine type, polybutadiene type, and alkyl titanate type. These resins can be used alone or in combination of two or more kinds, and can be three-dimensionally crosslinked by using various curing agents, crosslinking agents and the like.

To more specifically exemplify a particularly preferable cured film, when various characteristics such as surface hardness, heat resistance, chemical resistance, and transparency are taken into consideration, a silicone resin is used as the organic polymer. Is preferable, and an active energy ray-curable composition containing a silane coupling agent having an acryloyl group or a methacryloyl group is particularly preferable. When an active energy ray-curable composition containing a silane coupling agent having an acryloyl group or a methacryloyl group is used, in particular, the adhesion between the gas barrier film made of a metal oxide and the like and the cured film is improved, and the gas barrier property is improved. Especially improved. The reason for this is not clear, but the improvement in adhesion is due to the fact that the silane coupling agent reacts chemically with the metal oxide thin film and reacts with other film forming components in which the acryloyl group and methacryloyl group of the silane coupling agent coexist. It is believed that this is due to the hardened film being firmly bonded to the metal oxide thin film. Also, the improvement of gas barrier property,
It is considered that the gaps between the metal oxide particles forming the metal oxide thin film are filled with the silane coupling agent or the film-forming component that has reacted with the acryloyl group or methacryloyl group.

The silane coupling agent may be one having at least one of an acryloyl group and a methacryloyl group, but is preferably one having an acryloyl group having a high reaction rate. For example, if a silane coupling agent having only an isocyanate group or a mercapto group as a reactive group and not an acryloyl group or a methacryloyl group is used, the adhesiveness is not improved. This is probably because even if the bond between the silane coupling agent and the metal oxide thin film is formed, the silane coupling agent reacts with other coexisting film forming components and is difficult to be incorporated into the film. Be done.

Examples of the silane coupling agent having an acryloyl group or a methacryloyl group include γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane and γ-methacryloxypropyl. Triethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-acryloxypropylmethyldiethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxypropyl-tris ( β
-Methoxyethoxy) silane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane and the like.

These silane coupling agents are usually contained in the curable composition in an amount of 0.1 to 60% by weight, preferably 0.1% by weight.
It accounts for 2-45% by weight. If the amount of the silane coupling agent is too small, the adhesion between the cured film and the metal oxide thin film will not be sufficiently exhibited. It is considered that this is because the amount of functional groups that react with the metal oxide thin film in the composition is not sufficient. On the contrary, when the silane coupling agent is excessively present, the alkali resistance of the cured film may be deteriorated. It is considered that this is because a large amount of the silane coupling agent that does not react with the metal oxide thin film remains in the cured film, and this reacts with the alkali.

The curable composition is composed of a conventional monomer, oligomer, polymer or the like which is polymerized by irradiation of active energy rays to form a cured film, except that it contains a silane coupling agent. For example, monomers and oligomers such as epoxy (meth) acrylate, urethane (meth) acrylate, polyester (meth) acrylate are used. Some of these are trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate. Methacrylate, isoamyl acrylate, ethoxydiethylene glycol acrylate, methoxydiethylene glycol acrylate, N-vinylpyrrolidone, etc.
Examples include monofunctional and polyfunctional acrylic monomers, methacrylic monomers, and vinyl monomers having one or more carbon-carbon double bonds.

Various curing agents may be used in combination in the coating composition used for forming the cured film, for the purpose of accelerating curing and curing at low temperature. As the curing agent, various epoxy resin curing agents or various organic silicon resin curing agents are used. Specific examples of these curing agents include various organic acids and their acid anhydrides, nitrogen-containing organic compounds, various metal complex compounds, metal alkoxides, various salts such as organic carboxylates and carbonates of alkali metals, and peroxides. Examples thereof include radical polymerization initiators such as oxides and azobisisobutyronitrile. These curing agents can be used as a mixture of two or more kinds.

The film thickness of the above-mentioned cured film is usually 0.1 to 50 μm, preferably 0.3 to 10 μm from the viewpoint of maintaining the adhesive strength and hardness. In addition, in coating the coating, the coating composition is diluted with various solvents for the purpose of workability and adjustment of the coating thickness. As the diluting solvent, for example, water, alcohols, esters, ethers, halogenated hydrocarbons, dimethylformamide, dimethylsulfoxide and the like can be variously used depending on the purpose, and a mixed solvent can be used if necessary. is there. From the viewpoint of dispersibility of the particulate inorganic oxide, water, alcohol, dimethylformamide, ethylene glycol, diethylene glycol, triethylene glycol,
A polar solvent such as benzyl alcohol, phenethyl alcohol or phenyl cellosolve is preferably used. In order to form a cured film with the curable composition, the active energy ray curable composition is gravure coated, reverse coated,
It may be coated by various coating methods such as a die coating method and cured by irradiating with active energy rays. At this time, preheating may be performed after coating and before curing. When the active energy ray-curable composition is diluted with a solvent, the solvent must be removed in this preheating step.

(Conductive Layer) Examples of the conductive substance forming the conductive layer include indium oxide, tin oxide, gold, silver, copper, nickel and the like, and these may be used alone or in combination of two or more. it can. Of these, indium tin oxide (hereinafter referred to as “ITO”), which is usually a mixture of 99 to 90% indium oxide and 1 to 10% tin oxide, is particularly preferable in terms of the balance between transparency and conductivity. As the method for forming the conductive layer, a conventionally known vacuum vapor deposition method, sputtering method, ion plating method, chemical vapor deposition method, or the like can be used. Of these, the sputtering method is preferable from the viewpoint of adhesion. The thickness of the conductive layer is preferably in the range of 50 to 200 nm from the viewpoint of the balance between transparency and conductivity.

(Gas Barrier Layer) Since the conductive plastic laminate of the present invention is often required to have a high gas barrier property depending on its application, it is an optional layer, but it is desirable to separately provide a gas barrier layer. . Examples of the gas barrier layer include an inorganic oxide film or a gas barrier resin layer made of ethylene-vinyl alcohol copolymer, vinylidene chloride, or the like, but the inorganic oxide film is preferable. The inorganic oxides are oxides of metals, non-metals, and submetals, and specific examples thereof include aluminum oxide, zinc oxide, antimony oxide, indium oxide, calcium oxide, cadmium oxide, silver oxide, gold oxide, and chromium oxide. , Silicon oxide, cobalt oxide, zirconium oxide, tin oxide, titanium oxide, iron oxide, copper oxide, nickel oxide,
Platinum oxide, palladium oxide, bismuth oxide, magnesium oxide, manganese oxide, molybdenum oxide, vanadium oxide, barium oxide and the like can be mentioned, but silicon oxide is particularly preferable. Examples of the method of forming the gas barrier layer include a method of coating a resin and the like, and a method of forming a vapor deposition film made of an inorganic oxide. As a method of forming a vapor deposition film,
Conventionally known methods such as a vacuum vapor deposition method, a vacuum sputtering method, an ion plating method and a CVD method can be used. The thickness of the gas barrier film described above is not particularly limited, and varies depending on the types of constituent components of the gas barrier film, but considering the oxygen gas barrier property, the water vapor barrier property, and the economical efficiency, the film thickness is 5 to 100 nm. preferable.

(Conductive Plastic Laminate) In the conductive plastic laminate of the present invention, the plastic base material layer, the conductive layer and the cured coating layer are essential constituent layers as described above, and if necessary, a gas barrier layer and the like. Add arbitrary constituent layers. The layer structure of this conductive plastic laminate is optional except that it is essential to have a cured coating layer between the plastic substrate layer and the conductive layer, but the plastic substrate layer / cured coating layer / Conductive layer, plastic substrate layer / gas barrier layer / cured coating layer / conductive layer, plastic substrate layer /
Cured coating layer / gas barrier layer / conductive layer, gas barrier layer / plastic substrate layer / cured coating layer / conductive layer, cured coating layer /
Examples of the layer structure include a plastic substrate layer / cured coating layer / conductive layer, a cured coating layer / gas barrier layer / plastic substrate layer / cured coating layer / conductive layer. By adopting such a configuration in which the cured coating layer is interposed between the plastic base material layer and the conductive layer film, the adhesion of the conductive layer becomes good.

In the conductive plastic laminate of the present invention, in addition to the above layer constitution, the physical properties of the cured coating layer are important,
The hardness of the cured coating layer is 0.05 or more and 0.20 GP or less, preferably 0.15 GP or less. Further, like the hardness of the cured coating layer, the elastic modulus of the cured coating layer is also important in defining the properties of the conductive plastic laminate, and is particularly preferably 1.0 GP or more and 4.0 GP or less. . By satisfying the characteristics of the physical properties, even if the conductive plastic laminate is bent, the conductive layer is not cracked and the electric resistance value is not deteriorated. Therefore, the conductive plastic laminate with high bending resistance is provided. Therefore, it can be suitably used for substrates in the field of optoelectronics such as liquid crystal display devices and touch panels. Then, in order to make the hardness of the cured coating layer a specific value or more, it is possible to change the prescription and the curing conditions.

The hardness and elastic modulus of the above cured coating layer can be measured by an indentation test (indentation test). In the thin film hardness measurement, it is generally necessary to set the indentation depth of the indenter to be within about 1/10 of the film thickness. For example, PicoIndent manufactured by Hysitron
It can be measured using er or the like. In the indentation test, a load is applied to push the indenter into the test object, and an indentation curve (load-indentation depth curve) is obtained. The hardness H is represented by the ratio of the maximum load P at that time and the contact projected area A between the indenter and the test object (see the following equation (1)).

[0021]

## EQU1 ## H = P / A (1) Further, the compound elastic modulus Er can be obtained from the initial gradient S of the unloading curve of the indentation curve by the following equation (2).

[0022]

[Equation 2] S = (2 / √π) · Er · β · √A (2) Furthermore, according to the following equation (3), Young's modulus Ei of the indenter, Poisson's ratio vi of the indenter, Poisson's ratio of the DUT The Young's modulus Es of the specific test body is obtained from vs.

[0023]

## EQU3 ## Er = 1 / {(1-vs2) / Es + (1-vi2) / Ei} (3) However, since the Poisson's ratio vs of the cured coating layer as the test object is unknown here, It was expressed as "elastic modulus" using the composite elastic modulus Er. Also, the indenter is diamond, the Young's modulus Ei is 1140 GPa, and the Poisson's ratio is 0.07. For details, see WCOliver a
nd GMPharr, J. Mater. Res., Vol.7, No.6, Jun 1992
Or Handbook of Micro / Nanotribology.

[0024]

EXAMPLES The contents and effects of the present invention will be described below in more detail with reference to Examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. The plastic laminates obtained in the examples and comparative examples were evaluated by the following methods. <Layer Thickness> Regarding the gas barrier layer and the conductive layer of the laminates obtained in Examples and Comparative Examples, the cross section of the laminate was observed with a transmission electron microscope (Hitachi, H-600 type), and the thickness was measured. Was measured. <Surface Resistance Value of Conductive Layer> The surface resistance value was measured using a 4-terminal method resistance meter (Lorestar MP) manufactured by Mitsubishi Chemical Corporation. <Bending Resistance Test of Conductive Layer> A plastic laminate having a size of 5 × 10 cm is provided with φ2 along the long side with the conductive film inside.
After winding the plastic laminate around a 5 mm stainless tube and winding the conductive film outside, the presence of cracks in the conductive film was examined with an optical microscope, and the surface resistance value was measured by the above method. <Cured coating layer indentation test> Hysitr
Using a PicoIndenter manufactured by ON Co., a load (μN) at which the indenter indentation depth becomes about 1/10 of the film thickness
Then, one indent (indentation) was performed for 10 seconds, and the average value was obtained by measuring 5 times for each sample. In each measurement, the distance between the measurement points was set so that the influence of the indentation did not occur. Further, the sample was sufficiently fixed on the sample table.

Example 1 Bisoxymethyltricyclo [5.2.1.02,6]
Decanedimethacrylate 100 parts by weight, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (“Lucirin TPO” manufactured by BASF) as a photoinitiator.
0.05 parts by weight of benzophenone and 0.05 parts by weight of benzophenone were uniformly mixed and stirred, and then defoamed to obtain a composition. This composition was poured into a mold of optically polished glass using a silicon plate having a thickness of 0.4 mm as a spacer, and output 80 on the glass surface.
40 on the glass mold surface with a W / cm metal halide lamp
After irradiating so as to have an energy of J / cm ² , the glass mold was released to obtain a photocurable resin sheet having a thickness of about 0.4 mm.

The following components A, B, F and G were mixed on the resulting cured resin sheet layer in the proportions of 62, 38, 5 and 0.3% respectively, diluted with propylene glycol monomethyl ether and spun. Apply with a coat and output 80 W / c
Irradiation was performed with a metal halide lamp of m so that the energy was 5 J / cm ² , and a cured coating was laminated. Furthermore,
A 10 nm-thick silicon oxide thin film was formed on the cured coating by an RF sputtering machine manufactured by ULVAC, Inc. with a total pressure of argon gas of 6.7 × 10 ⁻¹ Pa and a target material SIO.
Subsequently, the partial pressure of oxygen was 1 × 10 ^-2 Pa and the total pressure was 6.7 × 1.
An ITO film having a thickness of 120 nm was formed from a target material ITO (indium oxide: tin oxide = 95: 5 (weight ratio)) at 0 ⁻¹ Pa to obtain a plastic laminate. Table 1 shows the evaluation results of the laminate.

Example 2 Example except that the prescription components of the cured film were changed to those in which the following components A, B, C, F and G were mixed in 40, 35, 25, 5 and 0.3% respectively. A plastic laminate was obtained in the same manner as in 1. Table 1 shows the evaluation results of the laminate. Example 3 The components of the cured coating were the following components A, B, C, E, F,
A plastic laminate was obtained in the same manner as in Example 1 except that G was mixed with 20, 25, 35, 20, 5, and 0.3%, respectively. Table 1 shows the evaluation results of the laminate. Example 4 A plastic laminate was obtained in the same manner as in Example 1 except that the order of lamination was changed to a photocurable resin sheet, a silicon oxide thin film, a cured film, and an ITO film. Table 1 shows the evaluation results of the laminate. Example 5 A plastic laminate was obtained in the same manner as in Example 1 except that the silicon oxide thin film and the ITO film were formed by a DC sputtering machine manufactured by ULVAC. The evaluation results of the laminate are shown in Table-1.
Shown in.

Comparative Example 1 Example except that the prescription components of the cured film were changed to those in which the following components A, B, D, F and G were respectively mixed at 20, 15, 65, 5, and 0.3%. A plastic laminate was obtained in the same manner as in 1. Table 1 shows the evaluation results of the laminate. Comparative Example 2 Same as Example 1 except that the prescription components of the cured film were changed to those in which the following components A, B, E, F, and G were mixed in amounts of 20, 15, 65, 5, and 0.3%, respectively. Then, a plastic laminate was obtained. Table 1 shows the evaluation results of the laminate. (Cured film component) Component A: Dicyclopentanyl diacrylate, Kayarad R684 manufactured by Nippon Kayaku Co., Ltd. Component B; Mixture of trimethylolpropane triacrylate and epoxy acrylate, Kayalad R130 Component C manufactured by Nippon Kayaku Co., Ltd .; Pentaerythritol triacrylate, Kayarad PET30 component D manufactured by Nippon Kayaku Co., Ltd .; trimethylolpropane triacrylate, Kayarad TMPTA component E manufactured by Nippon Kayaku Co., Ltd .; Ditrimethylolpropane tetraacrylate, NK ester manufactured by Shin Nakamura Chemical Co., Ltd. AD-TMP component F; 1-hydroxycyclohexyl phenyl ketone and bis (2,6-dimethoxybenzoyl) -2,4,4
-A mixture of trimethylpentylphosphine oxide, Irgacure 1800 component G manufactured by Ciba-Geigy Japan Ltd .; polyether modified silicone, Kyoeisha Chemical Co., Ltd.
Granol 450

[0029]

[Table 1]

[0030]

The conductive plastic laminate of the present invention is
The conventional glass substrate process can be used without peeling or cracking of the conductive layer.
It has a particularly advantageous effect that it is lighter than a glass substrate and has excellent impact resistance, and its industrial utility value is extremely large.

Specifically, the conductive plastic laminate of the present invention is preferably used as a substrate for liquid crystal display devices, and includes TN (Twisted Nematic type) and STN (Super Twis).
ted Nematic type, ferroelectric liquid crystal (FLC)
Simple matrix type such as Liquid Cystal type, MIM
(Metal-Insulator-Metal) type, TFT (Thin-FilmTra
nsistor) type and other active matrix type liquid crystal display devices can be applied.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Seiichiro Hayakawa             8-3-1 Chuo, Ami-cho, Inashiki-gun, Ibaraki Prefecture             Mitsubishi Chemical Corporation Tsukuba Research Center F term (reference) 2H090 JA06 JB03 JC07 JD11 KA03                       LA01                 4F100 AA20 AA28 AA33 AK01A                       AK01C AK25 AR00B AR00D                       AT00A BA03 BA04 BA07                       BA10A BA10B BA10D GB41                       JD02D JG01B JK04 JK06                       JK07C JK10 JK12C JL03                       YY00C                 5B087 AA04 AE00 AE09 CC02 CC13                       CC14 CC37                 5F051 BA18 FA04 GA05 GA13

Claims (3)

[Claims] 1. A plastic laminate having a cured coating layer between a plastic substrate layer and a conductive layer, wherein the cured coating layer has a hardness of 0.05 or more and 0.20 GP or less. Conductive plastic laminate. 2. The cured film layer has an elastic modulus of 1.0 GP or more,
The conductive plastic laminate according to claim 1, which has a GP of 4.0 GP or less. 3. The conductive plastic laminate according to claim 1, which has a gas barrier layer.