JP2005129443A - Film for transparent conductive laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical-use easily adherable polyester film with excellent bruise resistance, adhesiveness, transparency, and easiness to slide, as well as heat resistance with little precipitation of low-molecule matters at heating. <P>SOLUTION: The film for a transparent conductive laminate is provided with a coating layer of a composition consisting of polyester resin with a glass transition point of 40 to 100°C and an intrinsic viscosity of 0.4 or more and less than 0.7 at least on one face of a laminated film with thermoplastic resin (a) with a compressive elasticity modulus of 2,000 N/mm<SP>2</SP>or less and thermoplastic resin (b) with a compressive elasticity modulus of 2,100 N/mm<SP>2</SP>or more laminated by a co-extrusion method. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a film for a transparent conductive laminate.

  Transparent and conductive thin films in the visible light region are used for new display methods such as liquid crystal displays and electroluminescence displays, transparent electrodes in touch panels, etc., as well as for preventing static charges and blocking electromagnetic waves in transparent articles. . Conventionally, a so-called conductive glass in which an indium oxide thin film is formed on glass is well known as a transparent conductive laminate having such a thin film. However, since the base material is glass, this is inferior in flexibility and workability and may not be preferable depending on the application.

  For this reason, in recent years, in addition to flexibility and workability, it has excellent impact resistance and light weight, so it has a transparent conductivity based on various plastic films including polyethylene terephthalate film. A laminate is used.

  When such a transparent conductive laminate is used particularly for display applications, the plastic film as the base material has a prism lens layer, a hard coat layer, an adhesive layer, an antireflection treatment layer, a sputter layer, etc. in addition to excellent transparency. Excellent easy adhesion is required.

  In addition, in an image display device using a plastic film as a base material, heat treatment may be performed to stabilize the dimensions of the plastic film. By this heat treatment, particularly when using a polyester film, low molecular weight substances generated during polymerization of the polyester may be deposited on the surface of the base material, and the transparency of the film may be deteriorated. This causes problems such as a decrease in product productivity. Also in the vapor deposition and sputtering process, low molecular weight substances may be deposited on the surface of the polyester film, and it may be difficult to provide a vapor deposition layer or a sputter layer uniformly. The original conductivity, gas barrier property, antireflection property, etc. There is a possibility that a problem that the performance of can not be achieved.

  The generation of low molecular weight substances from this polyester film can be suppressed by providing a specific layer on the substrate, but it is a very thin layer such as a primer layer that is applied to provide easy adhesion. Then, the effect of suppressing the occurrence of low molecular weight is small.

Japanese Patent No. 2667680 JP-A-8-244186 JP-A-8-244187 JP 2001-229736 A JP 2001-273817 A

  The present invention eliminates the problems of the prior art, and in a transparent conductive laminate using a film substrate, improves visibility and touch feeling, that is, improves the hitting point characteristics of the conductive thin film, and has a low molecular weight during heat treatment. To provide a film for a transparent conductive laminate, which has a small amount of deposits, is excellent in transparency, slipperiness and scratch resistance, and has excellent adhesion to a layer used for optical applications, particularly adhesion to a hard coat layer. Especially, it aims at providing the film for transparent conductive laminated bodies suitable as an object for touch panels.

That is, the present invention is obtained by coextrusion of layers of compression modulus 10～2000N / layer of mm ² of thermoplastic resin a and a thermoplastic resin b of the compression elastic modulus 2100～10000N / mm ² in contact with the layer And a transparent conductive laminate comprising a coating layer comprising a polyester resin composition having a glass transition temperature of 40 to 100 ° C. and an intrinsic viscosity of 0.4 or more and less than 0.7 provided on the laminate film. Film.

Hereinafter, the present invention will be described in detail.
[Laminated film]
In the present invention, a laminated film, the layer of compressive modulus 10～2000N / layer of low modulus thermoplastic resin mm ² and high modulus thermoplastic resin compressive elastic modulus 2100～10000N / mm ² in contact with the layer A laminated film obtained by a coextrusion method is used.

[Low modulus thermoplastic resin]
As the low modulus thermoplastic resin, one having a compressive modulus of 10 to 2000 N / mm ² , preferably 10 to 1500 N / mm ² , more preferably 10 to 1000 N / mm ² is used. If the compressive elastic modulus exceeds 2000 N / mm ² , the laminate has a high compressive elastic modulus, so that the laminate is not excellent in touch feeling. If the compression modulus is less than 10 N / nm ² , the strength is insufficient.

  As the low elastic modulus thermoplastic resin, a thermoplastic resin that can be softened and fluidized by heating and can be molded can be used that satisfies the above requirements. As this thermoplastic resin, thermoplastic elastomer resin, polyolefin resin such as polyethylene resin or polypropylene resin, polyvinyl chloride resin, polyester resin, polystyrene resin, polyamide resin can be used. This may be a copolymer such as random copolymer or block copolymer, or a blend. Among these, a thermoplastic elastomer resin is preferable because an excellent touch feeling can be obtained.

  The thermoplastic elastomer resin is an elastomer that can be melt-formed, and is composed of a flexible component (soft segment) having rubber elasticity in the molecule and a molecular constraint component (hard segment) for preventing plastic deformation. It is.

  Examples of such thermoplastic elastomers include polyester, polyolefin, polystyrene, polyurethane, polyvinyl chloride, crystalline 1,2-polybutadiene, polyamide, fluorine, ionomer, and polyisoprene elastomers. Preferably, a polyester elastomer is used.

  The polyolefin elastomer is an elastomer having an olefin resin as a hard segment, and includes a blend type and a polymerization type. In addition to simple blends, there are those that are partially cross-linked with an organic oxide or the like, and elastomers that are completely cross-linked with a rubber phase dispersed during compounding.

  Polystyrene elastomers are divided into polystyrene-polybutadiene-polystyrene, polystyrene-polyisoprene-polystyrene, polystyrene-polyethylene / polybutylene-polystyrene, etc. depending on the type of soft segment, and linear triblock, There are types such as radial block and multi-block.

  Polyurethane elastomers include polyesters and / or poly (oxyalkylene) glycols having a molecular weight of 1000 to 3000 and / or poly (oxyalkylene) glycols, diisocyanates and glycols and / or diamines as chain extenders, and optionally terminal hydroxyl groups. The thermoplastic polyurethane obtained by adding the polycarbonate which it has further and making it react can be mentioned. Examples of the diisocyanate include 2,4-tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, and dicyclohexyl-4,4′-diisocyanate. Examples of the chain extender include ethylene glycol, propylene glycol, 1,4-β-hydroxyethoxybenzene, ethylenediamine, butylenediamine, and propylenediamine.

  Examples of the polyamide-based elastomer include a copolymer of a lauryl lactam component, a poly (oxybutylene) glycol component, and a dicarboxylic acid component. In this case, in order to change the hardness of the elastomer, the molecular weight of poly (oxybutylene) glycol may be changed, or the copolymerization ratio of lauryl lactam may be changed.

  Examples of the polyester elastomer include a high melting point crystalline polymer segment (a) mainly composed of a crystalline aromatic polyester unit and a low melting point polymer segment (b) mainly composed of an aliphatic polyether unit and / or an aliphatic polyester unit. And a main component of the polyester block copolymer.

  Examples of the polyester used in the polyester elastomer include polyesters composed of aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and diols such as ethylene glycol, butylene glycol, and diethylene glycol. Moreover, homopolymers, such as poly (oxyethylene) glycol, poly (oxypropylene) glycol, poly (oxybutylene) glycol, these block copolymers, and a random copolymer can be illustrated.

  In the polyester-based elastomer, the high-melting crystalline polymer segment (a) is a polyester formed from an aromatic dicarboxylic acid or an ester-forming derivative thereof and an aliphatic diol, preferably terephthalic acid and / or dimethyl terephthalate, Polybutylene terephthalate derived from 1,4-butanediol, but in addition to this, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4 ′ A dicarboxylic acid component such as dicarboxylic acid, diphenoxyethanedicarboxylic acid, 5-sulfoisophthalic acid, or an ester-forming derivative thereof, and a diol having a molecular weight of 300 or less, such as ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethyl Aliphatic diols such as lenglycol, neopentyl glycol, decamethylene glycol, alicyclic diols such as 1,4-cyclohexanedimethanol, tricyclodecane dimethylol, xylylene glycol, bis (p-hydroxy) diphenyl, bis ( p-hydroxyphenyl) propane, 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane, bis [4- (2-hydroxy) phenyl] sulfone, 1,1-bis [4- (2-hydroxy) Ethoxy) phenyl] cyclohexane, 4,4′-dihydroxy-p-terphenyl, polyesters derived from aliphatic diols such as 4,4′-dihydroxy-p-quaterphenyl, or the dicarboxylic acid component and diol component thereof Copolymer poly using two or more types together It may be discarded.

  In the polyester elastomer, the low melting point polymer segment (b) is an aliphatic polyether and / or an aliphatic polyester. Aliphatic polyethers include poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (hexamethylene oxide) glycol, copolymers of ethylene oxide and propylene oxide, poly (propylene oxide) Examples thereof include ethylene oxide addition polymers of glycol and copolymers of ethylene oxide and tetrahydrofuran. Examples of the aliphatic polyester include poly (ε-caprolactone), polyenantlactone, polycaprolactone, polybutylene adipate, and polyethylene adipate. Poly (tetramethylene oxide) glycol, poly (propylene oxide) glycol ethylene oxide adduct, poly (ε-caprolactone) from the elastic properties of polyester block copolymers obtained from these aliphatic polyethers and / or aliphatic polyesters ), Polybutylene adipate, polyethylene adipate and the like are preferable. The number average molecular weight of these low-melting polymer segments is preferably about 300 to 6000 in the copolymerized state.

  The copolymerization amount of the low melting point polymer segment (b) in the polyester block copolymer is preferably 10 to 80% by weight, more preferably 15 to 75% by weight.

  The polyester block copolymer can be produced by a known method. For example, a method in which a lower alcohol diester of dicarboxylic acid, an excessive amount of low molecular weight glycol, and a low melting point polymer segment component are transesterified in the presence of a catalyst and the resulting reaction product is polycondensed, or an excess of dicarboxylic acid and excess A method in which an amount of glycol and a low-melting-point polymer segment component are esterified in the presence of a catalyst and the resulting reaction product is polycondensed, or a high-melting-point crystalline segment is prepared in advance, and then a low-melting-point segment component In the case of using a poly (ε-caprolactone) for the low-melting polymer segment, a method for randomizing by transesterification by adding a method, a method for connecting a high-melting crystalline segment and a low-melting polymer segment with a chain linking agent, It is a method of adding an ε-caprolactone monomer to a high melting crystalline segment. However, either method can be taken.

  The elastomer may contain an additive such as a fluorescent brightening agent, an antioxidant, a heat stabilizer, an antistatic agent, and a crystal nucleating agent in order to increase transparency, if necessary.

  For example, when a polyester elastomer is used, methods for improving the transparency include blending with other polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and addition of a crystal nucleating agent.

  For example, in the case of a crystal nucleating agent, 0.1 to 10% by weight, preferably 0.2 to 7% by weight, more preferably 0.3 to 5% by weight based on the weight of the elastomer may be added. Absent. Here, as the crystal nucleating agent, known ones such as a metal salt type and a sorbitol acetal type can be used.

  For example, in the case of a polyester-based elastomer, sodium salt of sodium carboxylate, acrylic acid and / or methacrylic acid copolymer may be mentioned. These may be used alone or in combination of two or more.

  In the present invention, a polyester elastomer is preferable from the viewpoint of heat resistance and production stability, and a polystyrene or olefin elastomer is preferable from the viewpoint of transparency.

  The low elastic modulus thermoplastic resin may be used alone or in combination of two or more resins.

[High modulus thermoplastic resin]
In the present invention, the high modulus thermoplastic resin has a compression modulus of 2100 to 10,000 N / mm ² . When the compression elastic modulus is less than 2100 N / mm ² , there is no elasticity of the resin, the hardness is insufficient, and the writing performance is inferior for touch panel applications. When the compression elastic modulus exceeds 10,000 N / mm ² , the flexibility and workability are poor.

  As the high elastic modulus thermoplastic resin, a thermoplastic resin that satisfies the above requirements among the thermoplastic resins that become soft and fluid when heated and can be molded can be used. For example, polyester resin, polyolefin resin (polyethylene resin or polypropylene resin), polystyrene resin, polyvinyl chloride resin, and polyamide resin can be exemplified. Among these, a polyester resin and a polystyrene resin are preferable. A polyester resin is preferable in terms of extrusion characteristics and stretching characteristics.

  A preferred polyester resin is a linear polyester composed of a dicarboxylic acid component and a glycol component. Examples of such polyester include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate. These may be homopolymers or copolymers.

  For example, when polyethylene terephthalate is used as a copolymer, the copolymer component may be a dicarboxylic acid component or a glycol component. Examples of the dicarboxylic acid component include aromatic dicarboxylic acids such as isophthalic acid, phthalic acid and naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and decanedicarboxylic acid, and cyclohexanedicarboxylic acid. Examples of the glycol component include aliphatic diols such as butanediol and hexanediol, and alicyclic diols such as cyclohexanedimethanol.

  Among these, preferred dicarboxylic acid components as copolymer components include isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid, and glycol components include cyclohexane dimethanol. A copolymerization component may be used independently and may use 2 or more types.

  In the present invention, the high elastic modulus thermoplastic resin can be produced by a conventionally known method. For example, as a method for producing a polyethylene terephthalate homopolymer or copolymer of polyester, terephthalic acid, ethylene glycol and an optional copolymerization component are esterified, and the resulting reaction product is further recycled. A method in which a condensation reaction is performed to form a polyester, or a method in which dimethyl terephthalate, ethylene glycol, and a copolymerization component added as necessary are transesterified, and the resulting reaction product is further polycondensed to form a polyester is preferably used. It is done.

  In addition, when manufacturing polyester, it is preferable to add other additives, for example, a fluorescent brightening agent, an antioxidant, a heat stabilizer, an antistatic agent, etc., because each physical property can be improved. Furthermore, it is preferable to add a crystal nucleating agent in order to increase transparency.

  In order to provide the film with appropriate slipperiness and workability, inert particles may be added to the high elastic modulus thermoplastic resin, particularly polyester, within a range that does not impair the characteristics of the present invention. Examples of the inert particles include fine particles (for example, kaolin, alumina, titanium oxide, calcium carbonate, silicon dioxide, etc.) containing the elements of IIA, IIB, IVA, and IVB of the periodic table, silicone resins, and crosslinks. Examples thereof include fine particles made of a polymer having good heat resistance such as polystyrene.

  In recent years, olefin resins such as isotactic polypropylene resin and syndiotactic polypropylene resin, syndiotactic polystyrene resin and the like have been developed by improving the catalyst. For example, syndiotactic polystyrene resin has good heat-and-heat dimensional stability, has the characteristics that it can be extruded and stretched, and has transparency, and exhibits superior characteristics for the purpose of this application. Therefore, the syndiotactic polystyrene resin can be preferably used as a high elastic modulus thermoplastic resin along with the polyester resin.

  Even if these resins are used alone, in order to further improve the stretchability, they may be copolymerized and used within a range not impairing the object of the present invention.

[Laminated structure]
The laminated film in the present invention includes a layer of a low elastic modulus thermoplastic resin and a layer of a high elastic modulus thermoplastic resin in contact with the layer. And it is preferable to have a stretch orientation structure of at least one axis.

  When the layer of the low elastic modulus thermoplastic resin is the A layer and the layer of the high elastic modulus thermoplastic resin is the B layer, B / A / B with the A layer as the inner layer (where / indicates the structure of the layer) ) Type 3 layer configuration, B / A / B / A / B type 5 layer configuration, and 7 layers, 9 layers,..., (2n + 1 (n is a positive integer)) layer in these order. A laminated structure can be mentioned as a preferable aspect of a laminated film.

  For example, a B / A / B type three-layer structure in which a polyester elastomer is used as a low elastic modulus thermoplastic resin as an A layer, a polyethylene terephthalate is used as a high elastic modulus thermoplastic resin as a B layer, and the A layer is an inner layer. The B / A / B / A / B type five-layer structure, and the multi-layer structure of seven layers, nine layers,..., (2n + 1 (n is a positive integer)) layer in this order is a preferred embodiment. is there.

  Moreover, when B layers are two or more layers, you may comprise one layer or more with a different polymer. For example, when the high-modulus thermoplastic resin is composed of one of two types of polymers (b1, b2), B1 / A / B2 (where B1 and B2 are the respective layers of the thermoplastic resins b1 and b2, respectively) It may be a three-layer structure of the type) or a five-layer structure of the B1 / A / B2 / A / B1 type. Of these layer configurations, 3 layers and 5 layers are preferable, and 3 layers are particularly preferable.

  The thickness of the high elastic modulus thermoplastic resin layer is preferably 1 to 200 μm, more preferably 5 to 150 μm, and still more preferably 10 to 100 μm. This thickness refers to the thickness of the total layer when the high elastic modulus thermoplastic resin layer is composed of a plurality of mutually contacting layers and constitutes the high elastic modulus thermoplastic resin layer as a whole.

  Moreover, it is preferable that the film of this invention has provided the layer of the high elastic modulus thermoplastic resin in the outermost layer of at least one side. When a dielectric thin film or a transparent conductive film is formed on a layer of low elastic modulus thermoplastic resin, the touch feeling is excellent. However, due to the low elastic modulus, the pressing force is applied to the dielectric thin film or conductive film. In many cases, the film is damaged and the film is broken, and as a result, the film becomes unusable.

[Production method of laminated film]
The laminated film in the present invention is produced by a coextrusion film forming method. When the specific example is demonstrated about the case of the said 3 layer film (B / A / B), for example, the elastomer chip | tip adjusted for the thermoplastic elastomer layer A is first dried and fuse | melted. In parallel with this, the polyester chip prepared for the polyester layer B is dried and melted as necessary. Subsequently, a laminated unstretched film is produced from these molten polymers inside the die by, for example, a simultaneous lamination extrusion method using a multi-manifold die. That is, the polymer melt forming the A layer and the polymer melt forming the B layer are laminated so as to be alternately formed, developed on a die, and extruded. At this time, the polymer laminated inside the die maintains the laminated form. The sheet extruded from the die is cooled and solidified by a casting drum to form a laminated unstretched film.

  This unstretchable stretchable laminated polyester film can be produced using a conventionally known film forming method such as a tenter method or an inflation method.

  For example, in the case of the tenter method, the obtained laminated unstretched film is heated by roll heating, infrared heating or the like, and stretched in the longitudinal direction to obtain a longitudinally stretched film. This stretching is preferably performed by utilizing the difference in peripheral speed between two or more rolls. The stretching temperature is preferably higher than the glass transition point (Tg) of the highest thermoplastic resin among the laminated thermoplastic resins, and more preferably 20 to 40 ° C. higher than Tg. The draw ratio depends on the requirements of this application and the properties of the thermoplastic resin used, but is preferably 1.5 times or more and 4.0 times or less. More preferably, it is preferably 2.0 times or more and 3.9 times or less. If it is less than 1.5 times, uneven thickness of the film will be worsened, and if it is 4.0 times or more, breakage may easily occur during film formation.

  The longitudinally stretched film can be successively subjected to lateral stretching, heat setting, and thermal relaxation to form a biaxially oriented film. These treatments are performed while the film is running. The transverse stretching process starts from a temperature 20 ° C. higher than the glass transition point (Tg) of the highest thermoplastic resin among the laminated thermoplastic resins. And it heats up to (120-30) degreeC temperature lower than melting | fusing point (Tm) of a thermoplastic resin. The stretching start temperature is preferably (Tg + 40) ° C. or lower. The maximum stretching temperature is preferably a temperature lower by (100 to 30) ° C. than the melting point (Tm) of the highest thermoplastic resin among the laminated thermoplastic resins.

  The temperature increase in the transverse stretching process may be continuous or stepwise (sequential). Usually, the temperature is raised sequentially. For example, the transverse stretching zone of the stenter is divided into a plurality of zones along the film running direction, and the temperature is raised by flowing a heating medium having a predetermined temperature for each zone. When the transverse stretching start temperature is too low, the film is torn, which is not preferable. On the other hand, if the maximum stretching temperature is lower than (Tm−120) ° C., the heat yield of the film increases, and the uniformity of physical properties in the width direction decreases, which is not preferable. On the other hand, if the maximum stretching temperature is higher than (Tm−20) ° C., the film becomes soft and the film is torn due to disturbance or the like.

  The transverse stretching ratio is preferably 1.5 times or more and 4.0 times or less, although it depends on the required characteristics of the application. More preferably, it is 2.5 times or more and 3.9 times or less. If it is 1.5 times or less, uneven thickness of the film is deteriorated, and if it is 4.0 times or more, breakage may easily occur during film formation.

[Coating layer]
In the present invention, a coating layer is provided on at least one side of the above-described laminated film. This coating layer is a coating layer made of a polyester resin having a glass transition temperature of 40 to 100 ° C. and an intrinsic viscosity of 0.4 or more and less than 0.7.

[Polyester resin]
As the polyester resin used for the coating layer, a polyester obtained from a dicarboxylic acid component and a diol component can be used. Examples of the polyvalent base component include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, pyromellitic acid, A dimer acid and 5-sodium sulfo isophthalic acid can be illustrated.

  As such a polyester resin, it is preferable to use a copolymer polyester using two or more kinds of dicarboxylic acid components. The polyester resin may contain an unsaturated polybasic acid component such as maleic acid or itaconic acid, or a hydroxycarboxylic acid component such as p-hydroxybenzoic acid, if it is in a slight amount.

  Examples of the diol component of the polyester resin include ethylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylene glycol, dimethylolpropane, and poly ( Examples thereof include ethylene oxide) glycol and poly (tetramethylene oxide) glycol.

  The polyester resin preferably has a glass transition point of 40 to 100 ° C. When the glass transition temperature is less than 40 ° C., blocking tends to occur between the films, and when it exceeds 100 ° C., the coating film becomes hard and brittle, and the scratch resistance is deteriorated. More preferably, it is 60-80 degreeC. Within this range, better adhesion and scratch resistance can be obtained.

  The intrinsic viscosity of the polyester resin is 0.4 or more and less than 0.7. If the intrinsic viscosity is less than 0.4, low molecular weight substances are generated from the polyester resin itself, which deteriorates the transparency of the substrate, which is not preferable. Preferably it is 0.5 or more and less than 0.7. If it is this range, since the generation | occurrence | production of the low molecular weight substance from polyester resin itself can be suppressed more highly more highly and the cohesion force of polyester resin becomes higher, more excellent adhesiveness and scratch resistance can be obtained.

  The polyester resin is preferably soluble or dispersible in water, but water-soluble one containing some organic solvent can also be used.

  The polyester resin can be produced, for example, by the following method. A dicarboxylic acid component and a diol component are charged into a transesterification reactor, a catalyst is added, methanol is distilled off by controlling the temperature at 230 ° C. in a nitrogen atmosphere, and a transesterification reaction is performed. Next, the temperature is gradually raised to 255 ° C., and the polycondensation reaction is carried out under reduced pressure in the system to obtain a polyester resin. When the molecular weight increases during the polycondensation, the melt viscosity increases and stirring in the system becomes difficult. The polyester resin used in the coating layer has a high melt viscosity despite its low molecular weight compared to homopolyethylene terephthalate, making stirring in the system very difficult, increasing the motor torque of the stirring equipment, and the shape of the blades Intrinsic viscosity can be increased by devising or extending the polymerization time. The content of the polyester resin in the coating layer in the coating layer is preferably 50 to 95% by weight, more preferably 60 to 90% by weight.

[Fine particles]
In the present invention, the coating layer preferably contains fine particles. Such fine particles have an average particle diameter of 20 to 200 nm, preferably 40 to 120 nm. If it is larger than 200 nm, the fine particles fall off easily, and if it is smaller than 20 nm, sufficient lubricity and scratch resistance may not be obtained. The fine particles are usually contained in the composition of the coating layer.

  Examples of the fine particles used in the present invention include calcium carbonate, magnesium carbonate, calcium oxide, zinc oxide, magnesium oxide, silicon oxide, sodium silicate, aluminum hydroxide, iron oxide, zirconium oxide, barium sulfate, titanium oxide, and tin oxide. Inorganic fine particles such as antimony trioxide, carbon black, molybdenum disulfide; organic fine particles such as acrylic crosslinked polymers, styrene crosslinked polymers, silicone resins, fluororesins, benzoguanamine resins, phenolic resins, nylon resins, etc. it can. One of these may be used, or two or more may be used.

  The content of fine particles in the coating layer is preferably 0.1 to 10% by weight per 100% by weight of the composition of the coating layer. If it is less than 0.1% by weight, sufficient lubricity and scratch resistance cannot be obtained, and if it exceeds 10% by weight, the cohesive strength of the coating film is lowered and the adhesiveness is deteriorated.

[Crosslinking agent]
It is preferable to mix | blend a crosslinking agent with the composition of an application layer, and an epoxy type crosslinking agent, an oxazoline type crosslinking agent, a melamine type crosslinking agent, and an isocyanate type crosslinking agent are preferable as a crosslinking agent. One of these may be used, or two or more may be used.

  Examples of the epoxy crosslinking agent include polyepoxy compounds, diepoxy compounds, monoepoxy compounds, and glycidylamine compounds. Here, examples of the polyepoxy compound include sorbitol, polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether. , Trimethylolpropane polyglycidyl ether, diepoxy compound, for example, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene Glycol diglycidyl ether, polypropylene glycol diglycidyl ether Ether, polytetramethylene glycol diglycidyl ether, as a monoepoxy compound, e.g., allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether. Examples of the glycidylamine compound include N, N, N ′, N ′,-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N-diglycidylamino) cyclohexane and the like.

  The oxazoline-based crosslinking agent is preferably a polymer containing an oxazoline group. Such a polymer can be prepared by polymerization of an addition polymerizable oxazoline group-containing monomer alone or with another monomer. Addition polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like can be mentioned, and one or a mixture of two or more thereof can be used. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer is not limited as long as it is a monomer copolymerizable with an addition-polymerizable oxazoline group-containing monomer, such as alkyl acrylate, alkyl methacrylate (the alkyl group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, (meth) acrylic acid esters such as n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, Unsaturated carboxylic acids such as styrenesulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); Unsaturated nitriles such as acrylonitrile, methacrylonitrile; acrylamide, methacrylamide, N-alkyl Acrylamide, N-alkyl methacrylate N, N-dialkylacrylamide, N, N-dialkylmethacrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl Groups, cyclohexyl groups, etc.); vinyl esters such as vinyl acetate, vinyl propionate, acrylic acid, methacrylic acid with polyalkylene oxide added to the ester moiety; methyl vinyl ether, ethyl vinyl ether, etc. Vinyl ethers; α-olefins such as ethylene and propylene; Halogen-containing α and β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride; α and β-unsaturations such as styrene and α-methylstyrene An aromatic monomer etc. can be mentioned, These 1 type or 2 types It may be used monomers above.

  The melamine-based crosslinking agent is preferably a compound obtained by reacting methylol melamine derivative obtained by condensing melamine and formaldehyde with methyl alcohol, ethyl alcohol, isopropyl alcohol or the like as a lower alcohol, and a mixture thereof. Examples of the methylol melamine derivative include monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, hexamethylol melamine and the like.

  Isocyanate-based crosslinking agents include, for example, tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, metaxylylene diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-diisocyanate hexane, tolylene diisocyanate and hexane triol. Products, adducts of tolylene diisocyanate and trimethylol propane, polyol-modified diphenylmethane-4,4'-diisocyanate, carbodiimide-modified diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 3,3'- Bitrilene-4,4 ′ diisocyanate, 3,3′dimethyldiphenylmethane-4,4′-diisocyanate, metaphenylene diisocyanate and the like can be mentioned.

  When the composition of the coating layer contains a crosslinking agent, the content of the crosslinking agent is preferably 0.1 to 30% by weight, more preferably 10 to 25% by weight per 100% by weight of the composition of the coating layer. If it is less than 0.1% by weight, the cohesive strength of the coating film may not be exhibited, and the adhesiveness may be insufficient. If it exceeds 30% by weight, the coating film becomes very hard, stress relaxation is reduced, adhesiveness is not exhibited, and when the coated film is recovered and used, foreign matter due to the crosslinked body may be generated, which is not preferable.

  As the crosslinking agent for the coating layer, an oxazoline-based crosslinking agent is preferable because it is easy to handle and the pot life of the coating solution is long.

[Aliphatic wax]
The coating layer preferably contains an aliphatic wax.
Specific examples of the aliphatic wax include plant waxes such as carnauba wax, candelilla wax, rice wax, wood wax, jojoba oil, palm wax, rosin-modified wax, olicuric wax, sugar cane wax, esparto wax, and bark wax. Animal waxes such as beeswax, lanolin, whale wax, ibota wax and shellac wax; mineral waxes such as montan wax, ozokerite and ceresin wax; petroleum waxes such as paraffin wax, microcrystalline wax and petrolactam; And synthetic hydrocarbon waxes such as polyethylene wax, oxidized polyethylene wax, polypropylene wax, and oxidized polypropylene wax. Among them, carnauba wax, paraffin wax, and polyethylene wax are particularly preferable because they are easy to adhere to hard coats and pressure-sensitive adhesives and have good lubricity. These are preferably used as an aqueous dispersion because of their ability to reduce environmental burden and ease of handling.

  The content of these aliphatic waxes in the coating layer composition is preferably 0.5 to 30% by weight, more preferably 1% to 10% by weight. If the content is less than 0.5% by weight, the slipperiness of the film surface may not be sufficiently obtained, which is not preferable. If it exceeds 30% by weight, adhesion to a polyester film substrate and easy adhesion to a hard coat or a pressure-sensitive adhesive may be insufficient, which is not preferable.

[Method of forming coating layer]
In the present invention, the composition used for coating the coating layer is in the form of an aqueous coating solution such as an aqueous solution, aqueous dispersion or emulsion to form a coating layer (hereinafter sometimes referred to as “coating film”). Are preferably used. In order to form the coating layer, other resins than the above-described composition, for example, an antistatic agent, a coloring agent, a surfactant, an ultraviolet absorber, and a crosslinking agent can be added as necessary.

  The solid content concentration of the aqueous coating liquid used in the present invention is usually preferably 20% by weight or less, and particularly preferably 1 to 10% by weight. When this ratio is less than 1% by weight, the coatability to the polyester film may be insufficient, and when it exceeds 20% by weight, the stability of the coating liquid and the appearance of the coating layer may be deteriorated.

  Application of the aqueous coating liquid to the laminated film can be carried out at an arbitrary stage, but it is preferably carried out in the production process of the laminated film, and moreover, it is applied to the laminated film before orientation crystallization is completed. Is preferred.

  Here, the laminated film before the crystal orientation is completed is an unstretched film, a uniaxially oriented film in which the unstretched film is oriented in either the longitudinal direction or the transverse direction, and further in two directions, the longitudinal direction and the transverse direction. And the like that have been oriented at a low magnification (biaxially stretched film before being finally re-stretched in the machine direction or the transverse direction to complete orientation crystallization). In particular, it is preferable to apply the aqueous coating liquid of the above composition to an unstretched film or a uniaxially stretched film oriented in one direction, and perform longitudinal stretching and / or lateral stretching and heat setting as it is.

  When applying an aqueous coating liquid to a film, as a pretreatment for improving the coating property, the film surface is subjected to physical treatment such as corona surface treatment, flame treatment, plasma treatment, etc., or chemically combined with the composition. It is preferable to use an inert surfactant in combination. Such a surfactant improves the function of promoting the wetting of the aqueous coating liquid onto the laminated film and the stability of the coating liquid. For example, polyoxyethylene-fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid Anionic and nonionic surfactants such as metal soaps, alkyl sulfates, alkyl sulfonates, and alkyl sulfosuccinates can be mentioned. The surfactant is preferably contained in the composition forming the coating layer in an amount of 1 to 10% by weight.

  The coating amount of the coating liquid is preferably such that the thickness of the coating layer is 0.01 to 0.3 μm, more preferably 0.02 to 0.25 μm. If the thickness of the coating layer is too thin, the adhesive strength is insufficient. Conversely, if the coating layer is too thick, blocking may occur or the haze value may increase, which is not preferable.

  As a coating method, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a roll brush method, a spray coating method, an air knife coating method, an impregnation method, a curtain coating method and the like can be used alone or in combination. In addition, a coating film may be formed only on one side of a film as needed, and may be formed on both surfaces.

[Light transmittance]
The transparent conductive laminate film of the present invention preferably has a light transmittance of 70% or more at a wavelength of 550 nm. If this is less than 70%, the necessary visibility as the transparent conductive laminate may be insufficient, which is not preferable. The light transmittance is more preferably 70% or more over the entire visible light wavelength (380 to 780 nm) range.

[Coefficient of friction]
The film for transparent conductive laminate of the present invention preferably has a friction coefficient (μs) on the surface of the coating layer of 0.8 or less. Such a film can be obtained by forming a coating layer made of the polyester resin.

  According to the present invention, the visibility and touch feeling, that is, the impact point characteristics of the conductive thin film are improved, the precipitation of low molecular weight substances during heat treatment is small, the transparency, the slipperiness and the scratch resistance are excellent, and the optical application. It is possible to provide a film for a transparent conductive laminate excellent in adhesive strength with a layer to be used, in particular, adhesiveness with a hard coat layer.

Hereinafter, the present invention will be described in more detail with reference to examples. Various physical properties were evaluated by the following methods.
(1) Thickness of each layer A sample was cut into a triangle, fixed in an embedded capsule, and then embedded in an epoxy resin. Then, the embedded sample was made into a thin film section having a thickness of 50 nm with a microtome (ULTRACUT-S) and then observed and photographed with a transmission electron microscope at an acceleration voltage of 100 kV. From these, the thickness of each layer was measured, and the average thickness and relative standard deviation were determined.

(2) Light transmittance The visible light transmittance at a light wavelength of 550 nm was measured using a spectroscopic analyzer MPC-3100 manufactured by Shimadzu Corporation.

(3) Compressive modulus The thermoplastic resin alone was taken out and a 3 mm thick sheet was prepared. About the obtained sheet | seat, it measured based on JISK7181.

(4) Touch feeling The surface of the obtained laminate was written with a spherical iron rod having a tip diameter of 3 mmφ, and the touch feeling was subjected to sensory evaluation based on the following criteria.
○: The writing taste is soft and very smooth.
Δ: The writing feeling is slightly inferior in softness, but does not become hard.
X: There is no soft feeling in writing taste and it feels very hard.

(5) Friction coefficient (μs)
In accordance with ASTM D1894-63, a slippery measuring device manufactured by Toyo Tester was used to measure the static friction coefficient (μs) between the coating film forming surface and the coating film non-forming surface on the opposite side. However, the thread plate was a glass plate and the load was 1 kg. The slipping property of the film was evaluated according to the following criteria.
◎: Friction coefficient (μs) ≦ 0.5 …… Extremely good sliding property ○: 0.5 <Friction coefficient (μs) ≦ 0.8 …… Good sliding property ×: 0.8 <Friction coefficient (μs) …… Poor slipperiness

(6) Hard Coat Adhesive A 10 μm thick hard coat layer is formed on the coating surface and a cross cut (100 squares of 1 mm ² ) is applied, and a 24 mm wide cellophane tape ( Nichiban Co., Ltd.) was affixed and peeled off rapidly at a peeling angle of 180 °, and then the peeled surface was observed and evaluated according to the following criteria.
5: Peeling area is less than 10% …… Adhesive strength is very good 4: Peeling area is 10% or more and less than 20% …… Adhesive force is good 3: Peeling area is 20% or more and less than 30% …… Adhesive strength is slightly good 2: Peeling Area is 30% or more and less than 40% …… Adhesive force failure 1: Peeling area is 40% or more …… Adhesive strength is extremely poor

(7) Blocking resistance Two films were overlapped so that the coated surfaces were in contact with each other, and a pressure of 0.6 kg / cm ² was applied to this under an atmosphere of 60 ° C. and 80% RH for 17 hours. Then, it peeled and the blocking resistance was evaluated by the following reference | standard by the peeling force (unit: mN / 5cm).
◎: Peeling force <98 …… Very good blocking resistance ◯: 98 ≦ Peeling force <147 …… Good blocking resistance Δ: 147 ≦ Peeling force <196 …… Blocking resistance somewhat good ×: 196 ≦ Peeling force …… Poor blocking resistance

(8) Glass transition temperature Approximately 10 mg of a sample is sealed in an aluminum pan for measurement and attached to a differential calorimeter (DuPont V4.OB2000 DSC), and the temperature is 25 ° C. to 300 ° C. at a rate of 20 ° C./min. The sample is taken out after being kept at 300 ° C. for 5 minutes, immediately transferred onto ice and rapidly cooled. The pan is again attached to the differential calorimeter, and the glass transition temperature (Tg: ° C.) is measured by increasing the temperature from 25 ° C. to 20 ° C./min.

(9) Intrinsic viscosity Intrinsic viscosity ([η] dl / g) was measured with an o-chlorophenol solution at 25 ° C.

(10) Heat resistance The film was heat-treated at 120 ° C for 60 minutes, and the amount of change in the haze value of the film was measured. The change in haze value of the film was evaluated according to the following criteria.
◎: Change in haze value ≦ 1.0% …… Excellent heat resistance of film ○: 1.0% <Change in haze value ≦ 2.5% …… Good heat resistance of film ×: 2.5% <Haze Value change amount …… Film heat resistance failure Haze value change amount = (Haze value of film after heat treatment)-(Haze value of film before heat treatment)

[Example 1]
Polyester elastomer (Nuberan B4032AT manufactured by Teijin Ltd .: compression elastic modulus 50 N / mm ² ) was used as the low elastic modulus thermoplastic resin a. This was dried at 110 ° C.
Polyethylene terephthalate (inherent viscosity = 0.65 dl / g: compression elastic modulus 5000 N / mm ² ) was used as the high elastic modulus thermoplastic resin b. To this, 0.05% by weight of porous agglomerated silica having an average particle size of 0.5 μm was added and dried at 160 ° C.

  Thereafter, the low modulus thermoplastic resin a is supplied to two single-screw extruders heated to 230 ° C. and the high modulus thermoplastic resin b is heated to 280 ° C., respectively, and melted. Laminated with a three-layer structure of B layer of resin b / A layer of low elastic modulus thermoplastic resin a / B layer of high elastic modulus thermoplastic resin b, and cast on a cooling drum in this state. Obtained. Subsequently, the unstretched film was stretched 3.3 times in the longitudinal direction at 100 ° C., and an aqueous coating liquid having a concentration of 6% shown in Table 1 was uniformly applied with a roll coater. Next, the film was stretched 3.5 times in the transverse direction at 120 ° C., and then heat set at 200 ° C. to obtain a laminated film. Table 2 shows the layer structure of the laminated film.

[Example 2]
A laminated film was obtained in the same manner as in Example 1 except that a polyester elastomer (Nuberan P4110AT manufactured by Teijin Ltd .: compression elastic modulus 50 N / mm ² ) was used as the low elastic modulus thermoplastic resin a. Table 2 shows the layer structure of the laminated film.

[Examples 3 to 10, Comparative Examples 4 to 6]
A laminated film was obtained in the same manner as in Example 2 except that the coating liquid shown in Table 1 was applied as shown in Table 2. Table 2 shows the layer structure of the laminated film. In Comparative Example 6, no coating solution was applied.

[Example 11]
As a low elastic modulus thermoplastic resin a, a copolymerized PET (inherent viscosity = 0.60 dl / g) obtained by copolymerizing 12 mol% (based on all acid components) of isophthalic acid with polyethylene terephthalate (hereinafter referred to as “PET”). A blend of 50 wt% and 50 wt% of copolymerized PET (inherent viscosity = 0.64 dl / g) obtained by copolymerizing 12 mol% of naphthalenedicarboxylic acid with PET (based on the total acid components) was used. . This was dried at 140 ° C. The compression elastic modulus of this blend was 1500 N / mm ² .

PET (compression elastic modulus 4500 N / mm ² ) was used as the high elastic modulus thermoplastic resin b. To this, 0.05% by weight of porous agglomerated silica having an average particle size of 0.5 μm was added and dried at 160 ° C.

  Thereafter, the low elastic modulus thermoplastic resin a is supplied to two single-screw extruders heated to 280 ° C. and the high elastic modulus thermoplastic resin b is heated to 280 ° C., respectively, and melted. Laminated with a three-layer structure of B layer of resin b / A layer of low elastic modulus thermoplastic resin a / B layer of high elastic modulus thermoplastic resin b, and cast on a cooling drum in this state. Obtained. Subsequently, the unstretched film was stretched in the longitudinal direction by 3.0 times at 100 ° C., and an aqueous coating liquid having a concentration of 6% shown in Table 1 was uniformly applied with a roll coater. Next, the film was stretched 3.3 times in the transverse direction at 120 ° C., and then heat set at 200 ° C. to obtain a laminated film. Table 2 shows the layer structure of the laminated film.

[Example 12]
Polyester elastomer (Nuberan B4032AT manufactured by Teijin Limited: compression elastic modulus 50 N / mm ² ) was used as the low elastic modulus thermoplastic resin a. This was dried at 110 ° C. Polyethylene-2,6-naphthalate (inherent viscosity 0.66 dl / g: compression elastic modulus 5500 N / mm ² ) was used as the high elastic modulus thermoplastic resin b. To this, 0.05% by weight of porous agglomerated silica having an average particle size of 0.5 μm was added and dried at 170 ° C.

  Thereafter, the low elastic modulus thermoplastic resin a is supplied to two single-screw extruders heated to 230 ° C. and the high elastic modulus thermoplastic resin b is heated to 300 ° C., respectively, and melted. Laminated with a three-layer structure of B layer of resin b / A layer of low elastic modulus thermoplastic resin a / B layer of high elastic modulus thermoplastic resin b, and cast on a cooling drum in this state. Obtained. Subsequently, the unstretched film was stretched 3.3 times in the longitudinal direction at 120 ° C., and an aqueous coating liquid having a concentration of 6% of coating agent 1 shown in Table 1 was uniformly applied with a roll coater. Next, the film was stretched 3.5 times in the transverse direction at 150 ° C., and then heat set at 220 ° C. to obtain a laminated film. Table 2 shows the layer structure of the laminated film.

[Example 13]
As a low-modulus thermoplastic resin a, a polystyrene elastomer (Kuraray Co., Ltd. Hibler 7125) is blended at a ratio of 60% by weight with polypropylene (Montel SDK Sunrise Allomer PL500A) at a ratio of 40% by weight. Used without drying. This blend had a compression modulus of 25 N / mm ² . The same PET as in Example 1 was used as the high elastic modulus thermoplastic resin b. To this, 0.05% by weight of porous agglomerated silica having an average particle size of 0.5 μm was added and dried at 160 ° C.

  Thereafter, the thermoplastic resin a was supplied to two single-screw extruders heated to 230 ° C. and the thermoplastic resin b was heated to 280 ° C., respectively, and melted. Lamination was performed in a three-layer configuration of layer A of low-modulus thermoplastic resin a / layer B of high-modulus thermoplastic resin b, and cast onto a cooling drum in this state to obtain an unstretched laminated film. Subsequently, the unstretched film was stretched 3.3 times in the longitudinal direction at 100 ° C., and an aqueous coating liquid having a concentration of 6% shown in Table 1 was uniformly applied with a roll coater. Next, the film was stretched 3.5 times in the transverse direction at 120 ° C., and then heat set at 200 ° C. to obtain a laminated film. Table 2 shows the layer structure of the laminated film.

[Example 14]
As a low-modulus thermoplastic resin a, a polystyrene elastomer (Kuraray Co., Ltd. Hibler 7125) is blended at a ratio of 60% by weight with polypropylene (Montel SDK Sunrise Allomer PL500A) at a ratio of 40% by weight. Used without drying. The compression elastic modulus of the blend was 25 N / mm ² . As the high modulus thermoplastic resin b, syndiotactic polystyrene resin (Zarek S100 manufactured by Idemitsu Petrochemical Co., Ltd .: compression modulus 2500 N / mm ² ) was used without drying.

  Thereafter, the low-melting point thermoplastic resin a is supplied to two single-screw extruders heated to 230 ° C. and the thermoplastic resin b is heated to 300 ° C., respectively, and then melted, and then the B layer of the high-melting point thermoplastic resin b inside the die. The film was laminated in a three-layer structure of / A layer of low-melting point thermoplastic resin a / B layer of high-melting point thermoplastic resin b, and cast on a cooling drum in this state to obtain an unstretched laminated film. Subsequently, the unstretched film was stretched 1.5 times in the longitudinal direction at 120 ° C., and an aqueous coating solution having a concentration of 6% shown in Table 1 was uniformly applied by a roll coater. Next, the film was stretched 1.5 times in the transverse direction at 120 ° C., and then heat set at 200 ° C. to obtain a laminated film. Table 2 shows the layer structure of the laminated film.

[Comparative Example 1]
The same PET as in Example 1 was used as the high melting point thermoplastic resin b. To this, 0.05% by weight of porous agglomerated silica having an average particle size of 0.5 μm was added and dried at 160 ° C. In this example, the low melting point thermoplastic resin a is not used, and only the high melting point thermoplastic resin b is used.

  Thereafter, the high melting point thermoplastic resin b was supplied to a single screw extruder heated to 280 ° C. and melted, and then cast on a cooling drum in this state to obtain an unstretched laminated film. Subsequently, the unstretched film was stretched 3.3 times in the longitudinal direction at 100 ° C., and an aqueous coating liquid having a concentration of 6% shown in Table 1 was uniformly applied with a roll coater. Next, the film was stretched 3.5 times in the transverse direction at 120 ° C., and then heat set at 200 ° C. to obtain a laminated film. Table 2 shows the layer structure of the laminated film.

  Since the obtained film did not have a laminated configuration, the light transmittance was high and the transparency was not a problem, but the rigidity of the film was strong and the touch feeling was inferior.

[Comparative Example 2]
A laminated elastomer film was obtained in the same manner as in Example 1 except that a polyester elastomer (Nuberan B4032AN manufactured by Teijin Ltd .: compression elastic modulus 50 N / mm ² ) was used as the low elastic modulus thermoplastic resin a. Table 2 shows the layer structure of the laminated film.

  Because of the high crystallinity of the polyester elastomer used, it became cloudy and the light transmittance was as low as 30%, resulting in a laminated film lacking transparency.

[Comparative Example 3]
As the low elastic modulus thermoplastic resin a, a blend of 90% by weight of the same PET as in Example 1 and 10% by weight of a polyester-based elastomer (Nuberan P4110AN manufactured by Teijin Ltd.) was used. This was dried at 110 ° C. The compression modulus of the blend was 2500 N / mm ² .

As the high elastic modulus thermoplastic resin b, PET (compression elastic modulus 5000 N / mm ² ) was used. 0.05% by weight of porous aggregated silica having an average particle size of 0.5 μm was added to this PET and dried at 160 ° C.

  Thereafter, the low modulus thermoplastic resin a is supplied to two single-screw extruders heated to 230 ° C. and the high modulus thermoplastic resin b is heated to 280 ° C., respectively, and melted. Laminated with a three-layer structure of B layer of resin b / A layer of low elastic modulus thermoplastic resin a / B layer of high elastic modulus thermoplastic resin b, and cast on a cooling drum in this state. Obtained. Subsequently, the unstretched film was stretched in the longitudinal direction by 13.3 times at 100 ° C., and an aqueous coating liquid having a concentration of 6% of coating agent 1 shown in Table 1 was uniformly applied with a roll coater. Next, the film was stretched 3.5 times in the transverse direction at 120 ° C., and then heat set at 200 ° C. to obtain a laminated film. Table 2 shows the layer structure of the laminated film.

  The obtained laminated film had a high light transmittance and had no problem with transparency, but was inferior in touch feeling because of the high compression elastic modulus of the thermoplastic resin a of the core layer.

The components constituting the coating layer are as follows.
Polyester 1: The acid component is composed of 75 mol% of 2,6-naphthalenedicarboxylic acid / 20 mol% of isophthalic acid / 5 mol% of 5-sodium sulfoisophthalic acid, and the glycol component is composed of 90 mol% of ethylene glycol / 10 mol% of diethylene glycol. (Tg = 80 ° C., average molecular weight 15000). Polyester 1 was produced as follows. That is, 51 parts of dimethyl 2,6-naphthalenedicarboxylate, 11 parts of dimethyl isophthalate, 4 parts of dimethyl 5-sodium sulfoisophthalate, 31 parts of ethylene glycol and 2 parts of diethylene glycol were charged into a reactor. 05 parts were added, the temperature was controlled at 230 ° C. under a nitrogen atmosphere, and the resulting methanol was distilled off to conduct a transesterification reaction. Next, the temperature of the reaction system was gradually raised to 255 ° C. in a polymerization kettle with high motor torque of the stirrer, and the inside of the system was reduced in pressure by 1 mmHg to carry out a polycondensation reaction to obtain polyester 1 having an intrinsic viscosity of 0.56. 25 parts of this polyester was dissolved in 75 parts of tetrahydrofuran, and 75 parts of water was dropped into the resulting solution under high-speed stirring at 10,000 rpm to obtain a milky white dispersion, and then this dispersion was subjected to a reduced pressure of 20 mmHg. Distilled and the tetrahydrofuran was distilled off. An aqueous dispersion of polyester 1 was obtained.

  Polyester 2: The acid component is composed of 95 mol% terephthalic acid / 5 mol% 5-sodium sulfoisophthalic acid, and the glycol component is composed of 90 mol% ethylene glycol / 10 mol% diethylene glycol (Tg = 72 ° C., average molecular weight 16000). . Polyester 2 was produced as follows. A reactor was charged with 56 parts of dimethyl terephthalate, 5 parts of dimethyl 5-sodium sulfoisophthalate, 36 parts of ethylene glycol, and 3 parts of diethylene glycol, and 0.05 parts of tetrabutoxy titanium was added thereto, and the temperature was changed to 230 under a nitrogen atmosphere. The mixture was heated to a temperature of 0 ° C., and the produced methanol was distilled off to conduct a transesterification reaction. Subsequently, the temperature of the reaction system was gradually raised to 255 ° C. in a polymerization kettle with high motor torque of a stirrer, and the inside of the system was reduced in pressure by 1 mmHg to carry out a polycondensation reaction to obtain polyester 2 having an intrinsic viscosity of 0.57. 25 parts of this polyester was dissolved in 75 parts of tetrahydrofuran, and 75 parts of water was dropped into the resulting solution under high-speed stirring at 10,000 rpm to obtain a milky white dispersion. Then, this dispersion was subjected to a reduced pressure of 20 mmHg. Distilled and the tetrahydrofuran was distilled off. An aqueous dispersion of polyester 2 was obtained.

  Polyester 3: The acid component is composed of 75 mol% of 2,6-naphthalenedicarboxylic acid / 20 mol% of isophthalic acid / 5 mol% of 5-sodium sulfoisophthalic acid, and the glycol component is composed of 90 mol% of ethylene glycol / 10 mol% of diethylene glycol. (Tg = 80 ° C., average molecular weight 10,000). Polyester 1 was produced as follows. That is, 51 parts of dimethyl 2,6-naphthalenedicarboxylate, 11 parts of dimethyl isophthalate, 4 parts of dimethyl 5-sodium sulfoisophthalate, 31 parts of ethylene glycol and 2 parts of diethylene glycol were charged into a reactor. 05 parts were added, the temperature was controlled at 230 ° C. in a nitrogen atmosphere, and the resulting methanol was distilled off to conduct a transesterification reaction. Next, a polycondensation reaction is carried out by increasing the temperature of the reaction system gradually to 255 ° C. in a polymerization kettle where the motor torque of the stirrer is normal, and reducing the pressure inside the system to 1 mmHg, and a polyester having an intrinsic viscosity of 0.38. 3 was obtained. 25 parts of this polyester was dissolved in 75 parts of tetrahydrofuran, and 75 parts of water was dropped into the resulting solution under high-speed stirring at 10,000 rpm to obtain a milky white dispersion. Then, this dispersion was subjected to a reduced pressure of 20 mmHg. Distilled and the tetrahydrofuran was distilled off. An aqueous dispersion of polyester 3 was obtained.

  Crosslinking agent 1: Consists of 30 mol% of methyl methacrylate / 2 mol% of 2-isopropenyl-2-oxazoline / 10 mol% of polyethylene oxide (n = 10) methacrylate / 30 mol% of acrylamide (Tg = 50 ° C.). The acrylic was produced as follows according to the method described in Production Examples 1 to 3 of JP-A-63-37167. That is, 302 parts of ion-exchanged water was charged into a four-necked flask and heated to 60 ° C. in a nitrogen stream, and then 0.5 parts of ammonium persulfate and 0.2 part of sodium hydrogen nitrite were added as a polymerization initiator. Furthermore, a mixture of monomers, 23.3 parts of methyl methacrylate, 22.6 parts of 2-isopropenyl-2-oxazoline, 40.7 parts of polyethylene oxide (n = 10) methacrylic acid, and 13.3 parts of acrylamide. The solution was added dropwise over 3 hours while adjusting the liquid temperature to 60 to 70 ° C. After completion of dropping, the reaction was continued with stirring while maintaining the same temperature range for 2 hours, and then cooled to obtain an acrylic aqueous dispersion having a solid content of 25%.

Crosslinking agent 2: methylolated melamine (trade name MX-035 manufactured by Sanwa Chemical Co., Ltd.)
Cross-linking agent 3: glycerol polyglycidyl ether (trade name Denacol EX-313, manufactured by Nagase ChemteX Corporation)
Crosslinking agent 4: Blocked isocyanate (trade name Elastolone BN-5, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

Fine particles 1: Composite inorganic particles of silica and titania (average particle size: 100 nm). The fine particles 1 were produced as follows according to the methods described in the production examples and examples of JP-A-7-2520. A glass reaction vessel with an inner volume of 4 liters equipped with a stirring blade was charged with 140 g of methanol, 260 g of isopropanol, and 100 g of aqueous ammonia (25% by weight) to prepare a reaction solution, and stirred while maintaining the temperature of the reaction solution at 40 ° C. did. Next, 542 g of silicon tetramethoxide (Si (OMe) ₄ , Colcoat Co., Ltd., trade name: methyl silicate 39) was charged into a 3 liter Erlenmeyer flask, and 195 g of methanol and 0.1 wt% hydrochloric acid were stirred. 28 g of an aqueous solution (35% hydrochloric acid, Wako Pure Chemical Industries, Ltd. diluted to 1/1000 with water) was added and stirred for about 10 minutes. Subsequently, a solution obtained by diluting 300 g of titanium tetraisopropoxide (Ti (Oi-Pr) ₄ , Nippon Soda Co., Ltd., product name; A-1 (TPT)) with 634 g of isopropanol was added, and a transparent uniform solution ( A co-condensate of silicon tetraalkoxide and titanium tetraalkoxide) was obtained. Each of 1699 g of the homogeneous solution and 480 g of aqueous ammonia (25% by weight) were simultaneously added dropwise to the reaction solution over a period of 2 hours with the dropping speed initially reduced and gradually increased toward the end. After completion of dropping, the obtained cohydrolyzate was filtered, the organic solvent was dried at 50 ° C., and then dispersed in water to obtain fine particles 1 having a concentration of 10% by weight.

Fine particle 2: silica filler (average particle diameter: 80 nm)
(Product name: Cataloid SI-80P, manufactured by Catalytic Chemical Industry)
Fine particle 3: acrylic filler (average particle size: 80 nm)
(Product name MX-80W manufactured by Nippon Shokubai Co., Ltd.)

Additive: Carnauba wax (trade name Cerosol 524, manufactured by Chukyo Yushi Co., Ltd.)
Wetting agent: polyoxyethylene (n = 7) lauryl ether (trade name NAROACTY N-70, manufactured by Sanyo Chemical Co., Ltd.)

  The film for transparent conductive laminates of the present invention can be suitably used particularly for touch panels.

Claims (15)

Layers and laminated films obtained by coextrusion of layers of a thermoplastic resin b of the compression elastic modulus 2100~10000N / mm ² in contact with the layer of thermoplastic resin a compression modulus 10~2000N / mm ^2, and A film for a transparent conductive laminate comprising a coating layer made of a polyester resin composition having a glass transition temperature of 40 to 100 ° C. and an intrinsic viscosity of 0.4 or more and less than 0.7 provided on a laminate film.   The film for transparent conductive laminates according to claim 1, wherein the composition of the coating layer contains fine particles having an average particle size of 20 to 200 nm.   The film for transparent conductive laminates according to claim 1, wherein the composition of the coating layer contains a crosslinking agent.   The film for transparent conductive laminates according to claim 3, wherein the crosslinking agent is at least one crosslinking agent selected from the group consisting of an epoxy crosslinking agent, an oxazoline crosslinking agent, a melamine crosslinking agent and an isocyanate crosslinking agent.   The film for transparent conductive laminates according to claim 1, wherein the composition of the coating layer contains 0.5 to 30% by weight of an aliphatic wax.   The film for a transparent conductive laminate according to claim 1, wherein the film is a stretched film for a transparent conductive laminate, and the light transmittance at a wavelength of 550 nm is 70% or more.   The film for transparent conductive laminates according to claim 1, wherein the thermoplastic resin b is a polyester resin.   The film for transparent conductive laminates according to claim 1, wherein the thermoplastic resin a is a thermoplastic elastomer resin.   The film for transparent conductive laminates according to claim 8, wherein the thermoplastic elastomer resin is a polyester-based thermoplastic elastomer resin.   The film for transparent conductive laminates according to claim 1, wherein the outermost layer of the laminate film is a layer of thermoplastic resin b.   The film for transparent conductive laminates according to claim 10, wherein the laminated film is formed by providing layers of the thermoplastic resin b on both sides of the layer of the thermoplastic resin a.   The film for transparent conductive laminates according to claim 1, wherein the light transmittance in the entire visible light wavelength range is 70% or more.   The film for transparent conductive laminates according to claim 1, which is used for a touch panel.   The transparent conductive laminated body using the film for transparent conductive laminated bodies in any one of Claims 1-13.   A touch panel using the transparent conductive laminate according to claim 14.