WO2016136518A1 - Multilayer film and method for producing same - Google Patents

Abstract

A multilayer film which is obtained by providing at least one surface of a polyester film with a resin layer, and which is characterized in that: the reflectance of the surface of the resin layer at a wavelength of 550 nm is 6.0% or more; the surface resistivity of the surface of the resin layer is 10¹² Ω/□ or less; and the amount of change ∆γ of the surface energy of the surface of the resin layer before and after a boiling test (namely, ∆γ = |(surface energy of resin layer after boiling test) - (surface energy of resin layer before boiling test)|) is 5 mN/m or less. Provided is a multilayer film which has excellent transparency, excellent interference spot suppression when a hard coat layer having high refractive index is laminated thereon, and excellent adhesion to a hard coat layer having high refractive index, and which exhibits high antistatic properties regardless of humidity.

Description

Laminated film and method for producing the same

The present invention relates to a laminated film in which a resin layer is provided on at least one side of a polyester film and a method for producing the same.

Thermoplastic resin films, especially biaxially stretched polyester films, have excellent properties such as mechanical properties, electrical properties, dimensional stability, transparency, and chemical resistance. Widely used in applications.

In recent years, polyester films have been used in various optical films, particularly in display member applications such as touch panels, liquid crystal display panels (LCD), plasma display panels (PDP), and organic electroluminescence (organic EL).

Especially in such applications, a hard coat film in which a hard coat layer is laminated on a polyester film is used. In this hard coat film, in order to improve the adhesion between the polyester film as a substrate and the hard coat layer, a coating layer having easy adhesion is often provided as the intermediate layer. In addition, since the polyester film is easily charged, dust is likely to adhere in the processing process of the hard coat layer, and foreign matter defects are often generated due to the dust adhesion, and the yield is often reduced. Therefore, an antistatic property is required for a film that is a base material of a hard coat film.

Furthermore, hard coat films are required to have adhesion to a substrate at room temperature, high temperature and high humidity, transparency, scratch resistance, antifouling properties, and the like. Moreover, since it is often used on the surface of a display or the like, the hard coat film is required to have visibility and design. When a hard coat layer is laminated on a polyester film that is a base material, if the refractive index of the hard coat layer and the polyester film that is the base material is different, interference spots due to interface reflection occur and visibility deteriorates. There is a need for reduction of interference spots.

Especially in recent years, with the further enlargement of screens, higher definition, and higher grades, the required level of interference spot suppression, transparency, and adhesion between layers, especially under fluorescent lamps, has increased.

On the other hand, when a refractive index adjustment layer composed of a high refractive index layer / low refractive index layer is laminated on the surface of the hard coat layer, by increasing the refractive index of the hard coat layer, high refractive index from the refractive index adjustment layer. The rate layer can be omitted. As a result, in the film manufacturing process, the process can be omitted without impairing the function, and the yield can be improved and the cost can be significantly reduced. This technology has attracted attention due to the recent strong demand for cost reduction.

When a hard coat layer having a high refractive index (for example, refractive index 1.63) is provided on a base polyester film (for example, refractive index 1.65), (a) After forming an easily bonding layer, the method of carrying out a calendar process to a base film and reducing the dispersion | variation in the local thickness of a base film is disclosed (patent document 1).

In addition, a method is disclosed in which (b) a layer having a low refractive index is provided on the surface layer of the base film, an easy-adhesion layer having an intermediate refractive index between the hard coat layer and the base film is provided, and interference cancellation is utilized. (Patent Document 2).

Further, (c) a method of providing a high refractive index easy-adhesion layer having a refractive index intermediate between them (1.63 to 1.66) between the hard coat layer and the substrate film is disclosed ( Patent Document 3).

Moreover, as a method for imparting antistatic properties to the polyester film, a method of applying an antistatic agent to a polyester resin (for example, see Patent Document 4), a method of applying a styrene sulfonic acid copolymer (for example, see Patent Document 5). )It has been known. These methods are antistatic methods using an ion conductive type antistatic agent.

Also, a method of providing a polyaniline conductive layer on the surface of a polyester film by coating or the like (for example, see Patent Document 6) is known. This method is an antistatic method using an electron conduction type antistatic agent.

Also known is a method of providing a layer of antimony-doped tin oxide conductive agent on the surface of a polyester film by coating or the like (Patent Document 7). This method is an antistatic method using an electron conduction type antistatic agent.

In addition, as an antistatic method using other electron conduction type compounds, an antistatic property imparting by a polythiophene conductive agent has been proposed. For example, an antistatic method (Patent Document 8) in which a coating liquid containing a polythiophene-based conductive agent and a latex polymer is applied is known. In addition, an antistatic property imparting that achieves both transparency and antistatic property of a coating film by using an epoxy crosslinking agent in combination with a polythiophene-based conductive agent has been proposed (Patent Document 9).

JP 2001-71439 A Japanese Patent No. 4169548 Japanese Patent No. 3632044 JP-A-60-141525 JP 61-204240 A JP-A-7-101016 Japanese Patent Laid-Open No. 11-278582 JP-A-6-295016 Japanese Patent No. 3966171

In the method of Patent Document 1, when a hard coat layer has a refractive index of 1.60 or less, interference spots can be relatively suppressed, but when a hard coat layer having a refractive index of 1.60 or more and 1.65 or less is laminated. Although the adhesion was good, interference spots were conspicuous. Further, the method of Patent Document 2 is applicable only when the material of the film serving as the base material is polyethylene naphthalene dicarboxylate (refractive index of 1.7 or more) and lacks versatility.

Patent Document 3 proposes a method of adding a water-soluble metal chelate compound or a metal acylate compound to a water-soluble polyester resin, respectively. However, water-soluble metal chelate compounds and metal acylate compounds often have high acidity, and aggregation occurs when other components are contained in the resin layer, resulting in a decrease in transparency or deterioration in interference plaque suppression. There was a problem to do.

Further, in the methods using the ion conductive type antistatic agent of Patent Documents 4 and 5, since the antistatic property depends on the humidity, there is a problem of charging depending on the humidity. In the methods of Patent Documents 6 to 9, although antistatic properties can be expressed without depending on humidity, interference spots are conspicuous when a high refractive index hard coat layer is laminated. There was a problem that the adhesiveness with the coat layer also deteriorated.

Therefore, the present invention eliminates the above-mentioned drawbacks, is excellent in transparency, interference spot suppression, adhesion to a substrate and a high refractive index hard coat layer, and also exhibits a high level of antistatic properties regardless of humidity. It is an object to provide a polyester film.

In order to solve the above problems, the laminated film of the present invention has the following constitution. That is, it is a laminated film in which a resin layer is provided on at least one side of a polyester film, the reflectance of the resin layer surface at a wavelength of 550 nm is 6.0% or more, and the surface specific resistance value of the resin layer surface is 10 The surface energy change Δγ (Δγ = | surface energy of the resin layer after the boiling treatment test−surface energy of the resin layer before the boiling treatment test |) before and after the boiling test of the resin layer surface is ¹² Ω / □ or less. It is a laminated film in which a resin layer is provided on at least one side of a polyester film of 5 mN / m or less.

The laminated film of the present invention is excellent in transparency, suppression of interference spots when a high refractive index hard coat layer is laminated, adhesiveness with a high refractive index hard coat layer, and has a high level of antistatic properties regardless of humidity. Can be expressed. Furthermore, in a film in which a high refractive index hard coat layer is laminated, antistatic properties can be exhibited even on the surface of the hard coat layer.

Hereinafter, the laminated film of the present invention will be described in detail.

The laminated film of the present invention is a laminated film in which a resin layer is provided on at least one side of a polyester film, the reflectance of the resin layer surface at a wavelength of 550 nm is 6.0% or more, and the surface of the resin layer surface The specific resistance value is 10 ¹² Ω / □ or less, and the surface energy change Δγ before and after the boiling test on the surface of the resin layer (Δγ = | the surface energy of the resin layer after the boiling test—the resin layer before the boiling test It is necessary that the surface energy |) is 5 mN / m or less.

The laminated film of the present invention requires that the resin layer has a reflectance of 6.0% or more at a wavelength of 550 nm. The reflectance at a wavelength of 550 nm on the surface of the resin layer represents the refractive index of the resin layer. When the reflectance at a wavelength of 550 nm is higher than 6.0%, the refractive index of the resin layer indicates that the refractive index is increased to a region close to the PET film, and when the high refractive index hard coat layer is laminated. It can have interference plaque suppression. More preferably, it is 6.0% or more and 6.5% or less. As a method of setting the reflectance at a wavelength of 550 nm on the surface of the resin layer to 6.0% or more, there are a method of containing a metal oxide particle (A) described later in the resin layer and a method of containing a metal chelate compound. Among these, the method using metal oxide particles (A) having a number average particle diameter of 3 nm or more and 50 nm or less is preferable from the viewpoint of excellent transparency and adhesiveness during wet heat treatment. In the method of containing a metal chelate compound, decomposition of the chelate bond by wet heat treatment proceeds, and there is a possibility that appearance deterioration with time and adhesion after wet heat treatment may occur.

In the laminated film of the present invention, the surface specific resistance value on the surface of the resin layer is required to be 10 ¹² Ω / □ or less. The surface specific resistance value on the surface of the resin layer is an index representing the antistatic property on the surface of the resin layer. When the surface specific resistance value on the surface of the resin layer is high, electricity hardly flows on the surface of the resin layer (easily charged), and when the surface specific resistance value is low, electricity easily flows (hardly charged). By setting the surface specific resistance value on the surface of the resin layer to 10 ¹² Ω / □ or less, a high level of antistatic property can be exhibited, and as a result, dust adhesion during processing can be prevented. The surface specific resistance value on the surface of the resin layer is more preferably 10 ¹¹ Ω / □ or less.
Furthermore, in the present invention, by setting the surface specific resistance value of the resin layer surface of the laminated film to 10 ¹¹ Ω / □ or less, the laminated hard coat in the film in which the high refractive index hard coat layer is laminated on the laminated film of the present invention. Antistatic properties can also be exhibited on the surface of the layer. The reason for this is estimated as follows. A general hard coat layer having a high refractive index is often composed of an acrylic resin and has a polar functional group such as a carboxyl group. For this reason, the hard coat layer can polarize polar functional groups such as carboxylic acid. Therefore, the hard coat layer is not a perfect insulator but an electric conductor having a large resistance. When the surface specific resistance value of the laminated film is 10 ¹¹ Ω / □ or less, even if charge is generated on the surface of the high refractive index hard coat layer (charges are accumulated), the charge is inside the high refractive index hard coat layer. Then, it flows to the resin layer of the laminated film below it, so that the charge can be efficiently flowed. As a result, it is estimated that in a film in which a high refractive index hard coat layer is laminated on a laminated film, the surface specific resistance of the high refractive index hard coat layer can be lowered (can be hardly charged).

Further, as a more interesting phenomenon, in the film in which the hard coat layer is laminated on the surface of the resin layer of the laminated film of the present invention, the amount of charge at the time of unwinding the roll winding the film on which the hard coat layer is laminated is suppressed. It has been found that it has the effect. This phenomenon is not only a so-called antistatic region where the surface specific resistance value on the surface of the hard coat layer is 10 ¹² Ω / □ or less but also a hard region generally called an insulating region exceeding 10 ¹³ Ω / □. It has also been confirmed on the surface of the coat layer. The reason for this is presumed that there is a small amount of charge flow that does not appear in the surface resistivity value. Therefore, the film obtained by laminating the hard coat layer on the resin layer surface of the laminated film of the present invention can prevent the adhesion of dust during film processing because the charge amount on the hard coat layer surface is suppressed.

Examples of the method for reducing the surface specific resistance value on the surface of the resin layer include a method in which the resin layer contains a conductive polymer or an ion conductive resin. Examples of the method for setting the surface resistivity of the resin layer to 10 ¹² Ω / □ or less include a method in which the resin layer contains a π-electron conjugated polymer compound (B) such as polythiophene or polyaniline, an ammonium salt, sulfone There is a method of containing an ion conductive compound such as an acid salt. Among these, even if the amount contained is small, the surface specific resistance value on the surface of the resin layer can be 10 ¹² Ω / □ or less. Therefore, using the π-electron conjugated polymer compound (B) has antistatic properties. It is preferable from the viewpoint of compatibility between low interference and adhesiveness. The lower limit of the surface specific resistance value on the surface of the resin layer is not particularly defined, but if the surface specific resistance is too small, the amount of the conductive polymer or ion conductive resin to be contained in the resin layer is small. Since it may increase and film forming property and transparency may decrease, it is preferably 10 ⁵ Ω / □ or more.

Further, the surface energy change Δγ before and after the boiling test on the surface of the resin layer is obtained by a method described later, and represents the change in the structure of the resin layer by the boiling test. A large surface energy change Δγ before and after the boiling test indicates a large change in the resin layer structure by the boiling test, and a small surface energy change Δγ before and after the boiling test indicates a small change in the resin layer structure by the boiling test. Represents that. By setting the surface energy change Δγ before and after the boiling test to 5 mN / m or less, in addition to transparency, it is possible to maintain excellent adhesion and antistatic properties with the high refractive index hard coat layer after the boiling treatment. . The surface energy change Δγ before and after the boiling test is more preferably 3 mN / m or less. The surface energy change Δγ before and after the boiling test can be made 5 mN / m or less by reducing the change in the chemical bond of the resin layer even when immersed in boiling water. In order to set the surface energy change Δγ before and after the boiling test to 5 mN / m or less, there are a method of highly crosslinking the resin constituting the resin layer, a method of increasing the Tg of the resin constituting the resin layer, and a method of hydrophobizing. Can be mentioned. Among these, the method of containing the epoxy compound (C) and the acrylic resin (D) in the resin layer is such that dense cross-linking is constructed in the resin layer, and the energy change Δγ before and after the boiling test is 5 mN / m or less. The reflectance and antistatic properties can be expressed, which is preferable.

In the laminated film of the present invention, the resin layer has a metal oxide particle (A) having a number average particle diameter of 3 nm to 50 nm, a π-electron conjugated polymer compound (B), and an epoxy compound (C). Containing acrylic resin (D) is excellent in transparency, suppression of interference spots when a high refractive index hard coat layer is laminated, adhesiveness with high refractive index hard coat layer, and high level antistatic regardless of humidity It is preferable because it can exhibit sex.

In the laminated film of the present invention, the arithmetic average roughness (Ra) of the resin layer surface is preferably 20 nm or less. By setting the arithmetic average roughness (Ra) of the resin layer surface to 20 nm or less, it is possible to suppress coating film scraping during processing, and excellent post-processing transparency, antistatic properties, and interference spot suppression properties. Can be. The arithmetic average roughness (Ra) on the surface of the resin layer can be reduced by reducing the number average particle diameter of the particles contained in the resin layer. However, if the particle size is too small, the van der Waals force between the particles becomes large and the particles are easily aggregated, and the arithmetic average roughness (Ra) may increase due to the generation of coarse particles due to aggregation. Therefore, the particles contained in the resin layer preferably have a number average particle size of 3 nm to 50 nm. Moreover, when using a metal oxide particle (A) as a particle contained in a resin layer, when an epoxy compound (C) is contained in the resin layer in addition to the metal oxide particle (A), the arithmetic average of the resin layer surface Roughness (Ra) can be reduced. The reason why the arithmetic average roughness of the resin layer surface is reduced when the epoxy compound (C) is contained together with the metal oxide particles (A) is that the epoxy compound (C) can improve the fluidity of the resin layer. Therefore, as a result, it is thought that there exists an effect which suppresses aggregation of a metal oxide particle (A).

[Metal oxide particles (A)]
In the laminated film of the present invention, the resin layer preferably contains metal oxide particles (A) having a number average particle diameter of 3 nm to 50 nm. By using such metal oxide particles (A), the reflectance at a wavelength of 550 nm on the surface of the resin layer can be increased. As a result, interference spots can be suppressed when a high refractive index hard coat layer is laminated on the resin layer of the laminated film of the present invention. Moreover, since the number average particle diameter of the metal oxide particles (A) is sufficiently smaller than the wavelength of visible light, the transparency of the laminated film can be enhanced.

The metal oxide particles (A) in the present invention are excellent in malleability and ductility, are good electrical and thermal conductors, and have a metallic luster, that is, boron (B), silicon (Si), arsenic (in the periodic table) As), tellurium (Te), and astatine (At) refers to oxide fine particles of elements located to the left of the diagonal line. Further, oxide fine particles of an element located on the right side of the alkaline earth metal (Group 2) in the periodic table are preferable.

As such metal oxide fine particles, those having high refractive index, preferably metal oxide particles having a refractive index of 1.6 or more are preferable from the viewpoint of interference interference suppression. Examples of the high refractive index metal oxide particles include TiO ₂ , ZrO ₂ , ZnO, CeO ₂ , SnO ₂ , Sb ₂ O ₅ , indium-doped tin oxide (ITO), phosphorus-doped tin oxide (PTO), Y ₂ O ₅ , _{la 2 O 3, Al 2 O} 3, and the like.

These metal oxide particles may be used individually by 1 type, and may be used in combination of 2 or more type. From the viewpoint of dispersion stability and refractive index, titanium oxide particles (TiO ₂ ) (A ₁ ′) and / or zirconium oxide particles (ZrO ₂ ) (A ₂ ′) are particularly preferable.

Here, the number average particle diameter of the metal oxide particles (A) will be described. Here, the number average particle diameter refers to the particle diameter determined by a transmission electron microscope (TEM). The magnification is 500,000 times, and the outer diameter of 10 particles existing on the screen is the number average particle diameter obtained by measuring a total of 100 particles for 10 fields of view. Here, the outer diameter means the maximum diameter of the particle (that is, the longest diameter of the particle and indicates the longest diameter in the particle). Similarly, in the case of a particle having a cavity inside, the maximum diameter of the particle is also defined. To express.

When the number average particle diameter of the metal oxide particles (A) is small, the van der Waals force between the metal oxide particles becomes very large, so that the metal oxide particles (A) are likely to aggregate and light is scattered, resulting in a decrease in transparency. is there. On the other hand, when the number average particle diameter of the metal oxide particles (A) is increased, it may become a starting point for scattering of light and haze may be increased or reflectance may be decreased. Therefore, the metal oxide particles (A) preferably have a number average particle diameter of 3 nm or more and 50 nm or less from the viewpoint of transparency. Preferably they are 10 nm or more and 45 nm or less, More preferably, they are 15 nm or more and 40 nm or less.

In the present invention, the content of the metal oxide particles (A) in the resin layer is preferably 30% by weight or more and 90% by weight or less with respect to the entire resin layer. By setting it as this range, the reflectance at a wavelength of 550 nm on the surface of the resin layer can be 6.0% or more, and the interference unevenness suppression property when the hard coat layer is laminated is excellent. The content of the metal oxide particles (A) in the resin layer is preferably 30% by weight to 80% by weight, and more preferably 30% by weight to 70% by weight. In the present invention, the content in the resin layer represents the content in the solid content ([(weight of resin composition) − (weight of solvent)]) of the resin composition forming the resin layer.

In the present invention, the metal oxide particles (A) are more preferably particles (AD) having an acrylic resin (D) described later on part or all of the surface of the metal oxide particles (A). (The resin layer containing the particles (AD) naturally contains the metal oxide particles (A) and the acrylic resin (D)). When the oil layer contains such particles (AD), when the resin layer is formed using the resin composition described later, the metal oxide particles (A) and particles (AD) are further aggregated in the drying process. As a result, the surface roughness of the resin layer surface can be 20 nm or less. Moreover, it becomes possible to improve the transparency of the polyester film in which the resin layers are laminated.

Here, in the present invention, that the metal oxide particles (A) have the acrylic resin (D) on the surface thereof means that an acrylic resin (D) is present on a part or all of the surface of the metal oxide particles (A). ) Indicates adsorption / adhesion.

The method for producing the particles (AD) is not particularly limited, and examples thereof include a method of surface-treating the metal oxide particles (A) with an acrylic resin (D). Specifically, the following ( The methods i) to (iv) are exemplified. In the present invention, the surface treatment refers to a treatment for adsorbing and adhering the acrylic resin (D) to all or part of the surface of the metal oxide particles (A).

(I) A method in which a mixture prepared by previously mixing metal oxide particles (A) and acrylic resin (D) is added to a solvent and then dispersed.

(Ii) A method in which the metal oxide particles (A) and the acrylic resin (D) are sequentially added and dispersed in a solvent.

(Iii) A method in which the metal oxide particles (A) and the acrylic resin (D) are previously dispersed in a solvent and the obtained dispersion is mixed.

(Iv) A method of adding the acrylic resin (D) to the obtained dispersion after dispersing the metal oxide particles (A) in a solvent.

Further, as a dispersion apparatus, a dissolver, a high speed mixer, a homomixer, a mixer, a ball mill, a roll mill, a sand mill, a paint shaker, an SC mill, an annular mill, a pin mill, and the like can be used.

Further, as a dispersion method, a method of rotating the rotating shaft at a peripheral speed of 5 to 15 m / s for 5 to 10 hours using the above apparatus can be mentioned.

In addition, it is more preferable to use dispersed beads such as glass beads at the time of dispersion from the viewpoint of improving dispersibility. The bead diameter is preferably 0.05 to 0.5 mm, more preferably 0.08 to 0.5 mm, and particularly preferably 0.08 to 0.2 mm.

The mixing and stirring can be performed by shaking the container by hand, using a magnetic stirrer or stirring blade, irradiating with ultrasonic waves, vibrating and dispersing.

It should be noted that whether or not the acrylic resin (D) is adsorbed or adhered to all or a part of the surface of the metal oxide particles (A) can be confirmed by the following analysis method. An object to be measured (for example, a resin composition containing metal oxide particles (A)) is centrifuged with a Hitachi tabletop ultracentrifuge (manufactured by Hitachi Koki Co., Ltd .: CS150NX) (rotation speed 3,0000 rpm, separation time). 30 minutes), after allowing the metal oxide particles (A) (and the acrylic resin (D) adsorbed on the surface of the metal oxide particles (A)) to settle, the supernatant is removed, and the precipitate is concentrated to dryness. . The concentrated and dried precipitate is analyzed by X-ray photoelectron spectroscopy (XPS), and the presence or absence of the acrylic resin (D) on the surface of the metal oxide particles (A) is confirmed. When it is confirmed that 1% by weight or more of the acrylic resin (D) is present on the surface of the metal oxide particles (A) with respect to the total of 100% by weight of the metal oxide particles (A), the metal oxide particles It is assumed that the acrylic resin (D) is adsorbed and adhered to the surface of (A).

In addition, the presence or absence of particles (AD) in the resin layer of the laminated film is determined by using XPS while etching from the resin layer side of the laminated film with argon ions at an etching rate of 1 nm / min (in terms of SiO ₂ ). Can be confirmed. That is, when the presence of the acrylic resin (D) is confirmed on the surface of the metal oxide particles (A), it can be seen that the metal oxide particles (A) are particles (AD).

The acrylic resin (D) comprises a monomer unit (d1) represented by the formula (1), a monomer unit (d2) represented by the formula (2), and a monomer unit (d3) represented by the formula (3). It is preferable that it is the acrylic resin (D) which has.

(In Formula (1), R ₁ group represents a hydrogen atom or a methyl group. Further, n represents an integer of 9 or more and 34 or less.)

(In the formula (2), the R ₂ group represents a hydrogen atom or a methyl group. The R ₄ group represents a group containing two or more saturated carbocycles.)

(In the formula (3), the R ₃ group represents a hydrogen atom or a methyl group. The R ₅ group represents a hydroxyl group, a carboxyl group, a tertiary amino group, a quaternary ammonium base, a sulfonic acid group, or phosphoric acid. Represents a group.)
Since the acrylic resin (D) has the above monomer unit, the amount of energy change Δγ on the surface of the resin layer before and after the boiling test can be reduced while maintaining transparency, and the adhesiveness to the hard coat layer is strong. It is preferable because it can be made small. It is particularly preferable to use an acrylic resin (D) having a monomer unit in which the R ₃ group of formula (3) is a carboxyl group, because the adhesion can be further improved.

An acrylic resin (D) having a monomer unit (d1) represented by formula (1), a monomer unit (d2) represented by formula (2), and a monomer unit (d3) represented by formula (3) The content of is preferably 3 to 25 parts by weight with respect to 100 parts by weight of the metal oxide particles (A) contained in the resin layer. More preferably, they are 5 to 20 weight parts, More preferably, they are 7 to 15 weight parts. By setting it as the above range, the reflectance at a wavelength of 550 nm can be made 6.0% or more. As a result, the transparency of the resin layer is improved, and further, the interference spot suppression property at the time of laminating the hard coat layer is sufficient. It is preferable because it can be expressed in

Here, when the acrylic resin (D) in the present invention has the monomer unit (d1) represented by the formula (1), the dispersibility of the metal oxide particles (A) in the aqueous solvent is further improved and transparent. It is preferable because a laminated film having better properties can be obtained, and more preferable because interference spot suppression (visibility) when a high refractive index hard coat layer is laminated is further improved.

Here, in order that the acrylic resin (D) in the present invention has the monomer unit (d1) represented by the formula (1), the (meth) acrylate monomer (d1 ′) represented by the following formula (4): ) As a raw material, and polymerization is more preferable.

The (meth) acrylate monomer (d1 ′) is preferably a (meth) acrylate monomer represented by an integer of 9 or more and 34 or less, and more preferably 11 or more and 32 or less (meth) acrylate in the formula (4). Monomers, more preferably 13 to 30 (meth) acrylate monomers.

The (meth) acrylate monomer (d1 ′) is not particularly limited as long as n in the formula (4) is 9 or more and 34 or less, and specifically, decyl (meth) acrylate, dodecyl (meta) ) Acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, 1-methyltridecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, eicosyl (meth) acrylate, docosyl (meth) acrylate, tetracosyl (Meth) acrylate, triacontyl (meth) acrylate, etc. are mentioned, and dodecyl (meth) acrylate and tridecyl (meth) acrylate are particularly preferable. These may be used alone or in a mixture of two or more.

Further, the acrylic resin (D) in the present invention is preferably a resin having a monomer unit (d2) represented by the above formula (2).

In the formula (2), when an acrylic resin having a monomer unit containing two or more saturated carbocycles is used, it functions sufficiently as a steric hindrance so that the metal oxide particles (A) are aggregated in the resin composition. Alternatively, sedimentation can be suppressed, the reflectance of the resin layer at a wavelength of 550 nm can be 6.0% or more, and low coherence when the hard coat layer is laminated can be improved, which is preferable. Moreover, since aggregation of metal oxide particles (A) can be suppressed, coarse components in the resin layer can be reduced. As a result, the conductive polymer (B) can also be uniformly present in the resin layer, the surface specific resistance value of the resin layer can be made less than the twelfth power, and excellent antistatic properties can be exhibited. it can. Moreover, since a coarse component can be reduced, the surface roughness of a resin layer can be 20 nm or less, and it is excellent in the workability of a laminated film.

In order that the acrylic resin (D) in the present invention has the monomer unit (d2) represented by the formula (2), the (meth) acrylate monomer (d2 ′) represented by the following formula (5) is used as a raw material. It is preferable to use and polymerize.

As the (meth) acrylate monomer (d2 ′) represented by the formula (5), as R ₄ , a bridged condensed cyclic structure (a structure in which two or more rings each share two atoms and are bonded) ), Spirocyclic (having a structure in which two cyclic structures are shared by sharing one carbon atom), specifically, compounds having a bicyclo, tricyclo, tetracyclo group, etc. Among them, (meth) acrylates containing a bicyclo group are particularly preferable from the viewpoint of compatibility with the binder.

Examples of the (meth) acrylate containing the bicyclo group include isobornyl (meth) acrylate, bornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, adamantyl (meth) acrylate, and dimethyladamantyl (Meth) acrylate etc. are mentioned, and isobornyl (meth) acrylate is particularly preferred.

Furthermore, the acrylic resin (D) in the present invention is preferably a resin having a monomer unit (d3) represented by the formula (3).

When an acrylic resin having a monomer unit in which R ₅ group in Formula (3) has a hydroxyl group, a carboxyl group, a tertiary amino group, a quaternary ammonium group, a sulfonic acid group, or a phosphoric acid group is used, metal oxide particles ( Since A) can be uniformly dispersed in the resin layer, aggregation or sedimentation of the metal oxide particles (A) in the resin composition can be suppressed. Therefore, the reflectance of the resin layer at a wavelength of 550 nm is 6 0.0% or more. As a result, the low interference property when the hard coat layer is laminated can be improved, which is preferable.

In order that the acrylic resin (D) in the present invention has the monomer unit (d3) represented by the formula (3), the (meth) acrylate monomer (d3 ′) represented by the following formula (6) is used as a raw material. It is necessary to use and polymerize.

Examples of the (meth) acrylate monomer (d3 ′) represented by the formula (6) include the following compounds.

Examples of the (meth) acrylate monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene Examples include monoesterified products of polyhydric alcohols such as glycol mono (meth) acrylate and (meth) acrylic acid, or compounds obtained by ring-opening polymerization of ε-caprolapton to the monoesterified product, and particularly 2-hydroxyethyl ( Preferred are (meth) acrylate and 2-hydroxypropyl (meth) acrylate.

Examples of (meth) acrylate monomers having a carboxyl group include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, or hydroxyalkyl (meth) acrylates and acid anhydrides. A half esterified product of Acrylic acid and methacrylic acid are particularly preferable.

Tertiary amino group-containing monomers include N, N-, such as N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, and the like. N, N-dialkylamino such as dialkylaminoalkyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide Examples include alkyl (meth) acrylamide, and N, N-dimethylaminoethyl (meth) acrylate is particularly preferable.

As the quaternary ammonium group-containing monomer, a monomer obtained by allowing a quaternizing agent such as epihalohydrin, benzyl halide or alkyl halide to act on the above-mentioned tertiary amino group-containing monomer is preferable. Specifically, 2- (methacryloyloxy ) (Meth) acryloyloxyalkyltrialkylammonium salts such as ethyl trimethylammonium chloride, 2- (methacryloyloxy) ethyltrimethylammonium bromide, 2- (methacryloyloxy) ethyltrimethylammonium dimethyl phosphate, methacryloylaminopropyltrimethylammonium chloride, methacryloyl (Meth) acryloylaminoalkyltrialkylammonium salts such as aminopropyltrimethylammonium bromide, tetrabutylammonium Tetra (meth) acrylates such as Moniumu (meth) acrylate, and tri-alkyl benzyl ammonium (meth 9 acrylates such as trimethylbenzylammonium (meth) acrylate. In particular 2- (methacryloyloxy) ethyl trimethyl ammonium chloride are preferred.

Examples of the sulfonic acid group-containing monomer include (meth) acrylamide-alkanesulfonic acid such as butyl acrylamide sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, or sulfoalkyl (meth) such as 2-sulfoethyl (meth) acrylate. Examples thereof include acrylate, and 2-sulfoethyl (meth) acrylate is particularly preferable.

Examples of the phosphoric acid group-containing acrylic monomer include acid phosphooxyethyl (meth) acrylate, and acid phosphooxyethyl (meth) acrylate is particularly preferable.

In particular, in the present invention, by using a (meth) acrylate monomer having a carboxyl group as the (meth) acrylate monomer (d3 ′) represented by the formula (6), the energy change of the resin layer surface before and after the boiling test. The amount Δγ can be reduced. As a result, the adhesiveness between the resin layer and the hard coat layer can be made stronger, which is preferable. The reason is estimated that a stronger resin layer can be formed by the reaction of the carboxyl group with the epoxy compound.

[Π-electron conjugated polymer compound]
In the present invention, the resin layer preferably contains a π-electron conjugated polymer compound (B). In the present invention, a π-electron conjugated system means an alternating single bond and multiple bond, or a single bond and multiple bond, and an atom having an available p orbital such as oxygen or nitrogen delocalizes π electrons. Represents that In the present invention, the polymer compound represents a compound having a number average molecular weight of 3000 or more. The π-electron conjugated polymer compound (B) preferably has conductivity (surface specific resistance value is 10 × 10 or less). As the π-electron conjugated polymer compound used in the present invention, the repeating unit is aniline and / or a derivative thereof, pyrrole and / or a derivative thereof, isothianaphthene and / or a derivative thereof, acetylene and / or a derivative thereof, Thiophene and / or its derivatives are preferred. Among them, a π-electron conjugated polymer compound in which the repeating unit is thiophene and / or a derivative thereof is particularly preferable from the viewpoint of little coloring and high total light transmittance.

Examples of the π-electron conjugated polymer compound in which the repeating unit is thiophene and / or a derivative thereof include compounds having a structure in which the 3-position and 4-position of the thiophene ring are substituted. Those in which an oxygen atom is bonded to the 3rd and 4th carbon atoms are preferred. Some hydrogen atoms or carbon atoms bonded directly to carbon atoms have insufficient water solubility.

In addition, a preferable embodiment of the π-electron conjugated polymer compound in which the repeating unit is thiophene and / or a derivative thereof is one in which thiophene and / or the derivative thereof are polymerized in the presence of a polyanion. Examples of the polyanion include polyacrylic acid, polymethacrylic acid, polymaleic acid, polystyrene sulfonic acid, and the like, and polystyrene sulfonic acid is preferable from the viewpoint of conductivity.

By polymerizing the thiophene and / or derivative thereof in the presence of a polyanion, a repeating structure represented by the following formula (7) and / or

Repetitive structure represented by the following formula (8)

Can be obtained. In the repeating structure represented by the formula (7), R ₆ and R ₇ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group, or an aromatic hydrocarbon. Represents a group, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, cyclohexylene group, benzene group and the like. P is an integer of 2 or more. In the repeating structure represented by the formula (8), m is an integer of 1 to 4, and q is an integer of 2 or more.

In the present invention, the π-electron conjugated polymer compound (B) is preferably a polythiophene and / or a polythiophene derivative having a repeating structural formula represented by the formula (8), for example, repeating the formula (5) A structure having m = 1 (methylene group), m = 2 (ethylene group), and m = 3 (trimethylene group) is preferable. Among them, particularly preferred is an ethylene group compound of m = 2, that is, poly-3,4-ethylenedioxythiophene.

The above compound can be produced by the methods disclosed in, for example, JP-A No. 2000-6324, European Patent No. 602713, and US Pat. No. 5,391,472, but other methods may be used.

For example, 3,4-ethylenedioxythiophene was obtained using 3,4-dihydroxythiophene-2,5, -dicarboxyester alkali metal salt as a starting material, and then potassium peroxodisulfate and sulfuric acid were added to a polystyrenesulfonic acid aqueous solution. By introducing iron and the 3,4-ethylenedioxythiophene obtained above and reacting them, an acidic polymer such as polystyrene sulfonic acid is added to polythiophene such as poly (3,4-ethylenedioxythiophene). A complexed composition can be obtained.

As an aqueous coating composition containing poly-3,4-ethylenedioxythiophene and polystyrenesulfonic acid, H.P. C. A product sold as “Baytron” P from Starck (Germany) can be used.

In the present invention, the content of the π-electron conjugated polymer (B) contained in the resin layer is preferably in the range of 3 to 25 parts by weight, more preferably 100 parts by weight of the metal oxide particles (A). A range of 5 to 20 parts by weight is more preferable. By setting it as the said range, interference fringe suppression property and antistatic property can be made compatible.

[Epoxy compound (C)]
In the laminated film of the present invention, the resin layer preferably contains an epoxy compound (C). In the laminated film of the present invention, the resin layer contains the epoxy compound (C), thereby improving the fluidity when the resin layer is cured, and as a result, suppressing the aggregation of the metal oxide particles (A). The transparency of the laminated film can be imparted. Moreover, since the surface roughness of a resin layer can be made small by suppressing aggregation of metal oxide particle (A), the coating-film abrasion at the time of a process can be suppressed. For example, scratches during processing of the hard coat layer can be suppressed, and processing defects when further vapor deposition or sputtering is performed on the hard coat layer can be suppressed. In the present invention, that the resin layer contains an epoxy compound (C) means that it contains an epoxy compound or an epoxy compound derivative (such as a compound in which the epoxy compound is ring-opened).

Moreover, when an epoxy compound (C) and an acrylic resin (D) are contained in the resin layer of the laminated film of the present invention, a crosslinking reaction between the epoxy compound (C) and a carboxylic acid group contained in the acrylic resin (D) occurs. It progresses and the adhesiveness with the laminated body of a resin layer can be improved.

The molecular weight of the epoxy compound (C) used in the present invention is more preferably 1000 or less. When the molecular weight of the epoxy compound (C) is 1000 or less, the above-described effect of improving the fluidity of the resin composition can be made more remarkable.

On the other hand, for example, if the molecular weight becomes too large (the molecular weight exceeds 1000), a phenomenon such as cracking of the coating film occurs during stretching after coating and drying, and the effect of improving transparency may not be sufficiently obtained. There is sex.

In the present invention, the epoxy compound (C) is preferably a water-soluble compound. The water-soluble compound here refers to a compound having a water solubility of 80% or more. “Water solubility” refers to the proportion of a compound dissolved when 10 parts by weight of the solid content of the compound is dissolved in 90 parts by weight of water at 23 ° C. That is, 80% water solubility means a state in which 80% by weight of 10 parts by weight of a compound is dissolved in 90 parts by weight of water and the remaining 20% by weight of the compound remains as an undissolved substance at 23 ° C. Indicates. Moreover, 100% of water content represents the state which 10 weight part compound is melt | dissolving in 90 weight part water all at 23 degreeC. In the present invention, the epoxy compound (C) preferably has a water content of 90% or more, and more preferably has a water content of 100%. When the water solubility is high, not only the coating liquid itself can be made water-soluble, but also excellent in transparency, antistatic properties, and interference spot suppression properties.

Moreover, as a method for improving the fluidity at the time of curing of the resin layer, in addition to adding / containing the epoxy compound (C) to the resin layer, for example, adding / containing a high boiling point solvent such as glycerin. Is mentioned. The method of adding and containing the epoxy compound (C) to the resin layer is preferable because it does not cause blocking and does not cause contamination inside the tenter that performs heat treatment or air pollution, compared to the method of adding and containing a high boiling point solvent. is there.

In the laminated film of the present invention, the type of the epoxy compound (C) is not particularly limited, and examples thereof include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, diglycerol polyglycidyl ether, and polyethylene glycol diglycidyl ether. Can be used. For example, an epoxy compound “Denacol” manufactured by Nagase Chemtech Co., Ltd. (EX-611, EX-614B, EX-512, EX-521, EX-421, EX-313, EX-810, EX-830, EX-850, etc. ), Diepoxy / polyepoxy compounds (SR-EG, SR-8EG, SR-GLG, etc.) manufactured by Sakamoto Pharmaceutical Co., Ltd., epoxy compounds “EPICLON” EM-85-75W manufactured by Dainippon Ink Industries, Ltd., or CR- 5L or the like can be suitably used, and among them, those having water solubility are preferable.

The epoxy compound (C) is preferably one having an epoxy equivalent weight (WPE) of 100 to 300 WPE from the viewpoint of reactivity, and the epoxy equivalent is more preferably 110 to 200 WPE.

Here, the content of the epoxy compound (C) is preferably 20 parts by weight or more and 60 parts by weight or less, more preferably 30% by weight or more and 60% by weight or less, with respect to 100 parts by weight of the metal oxide particles (A). It is.

By making the epoxy compound (C) 20 wt% or more and 60 wt% or less with respect to 100 parts by weight of the metal oxide particles (A), the dispersibility of the metal oxide particles (A) is improved and the transparency is improved. In addition, the anti-interference spots, antistatic properties and anti-interference spots are improved.

[Ion conductive compound (E)]
In the laminated film of the present invention, from the viewpoint of improving the antistatic property, the resin layer may contain an ion conductive compound (E) instead of the π electron conjugated polymer compound (B). In the present invention, the ion conductive resin represents a resin having a property of conducting ions in the resin composition, and specifically includes a resin having a structure such as polystyrene sulfonate metal salt or ammonium metal salt. When the ion conductive compound (E) is contained in the resin layer, the charge can be transferred by ionic conduction, and excellent antistatic properties can be exhibited.

When producing the laminated film of the present invention, a method of applying a resin composition containing an aqueous solvent to a polyester film before completion of crystal orientation, and completing crystal orientation by stretching and heat treatment is suitably used. . This is because heat treatment at a high temperature is possible, the adhesive force between the base material and the resin layer is improved, and a more uniform and thin resin layer can be provided. When the resin layer is formed by this method, the resin composition is preferably an aqueous composition that can be dissolved, emulsified, or suspended in an aqueous solvent in view of environmental pollution and explosion resistance. Such resin compositions that can be dissolved, emulsified or suspended in water are copolymerized and reactive with monomers having a hydrophilic group (such as acrylic acid, methacrylic acid, acrylamide, vinyl sulfonic acid and salts thereof). It can be prepared by a method such as emulsion polymerization, suspension polymerization, soap-free polymerization using an emulsifier or a surfactant.

The polymerization initiator is not particularly limited, but is a general radical polymerization initiator, for example, a water-soluble peroxide such as potassium persulfate, ammonium persulfate, hydrogen peroxide, or benzoyl peroxide or t-butyl hydroper Oil-soluble peroxides such as oxides or azo compounds such as azodiisobutyronitrile can be used.

[Polyester film]
The polyester film used as the substrate film in the laminated film of the present invention will be described. First, polyester is a general term for polymers having an ester bond in the main chain, and includes ethylene terephthalate, propylene terephthalate, ethylene-2,6-naphthalate, butylene terephthalate, propylene-2,6-naphthalate, ethylene-α, β. Those having at least one component selected from -bis (2-chlorophenoxy) ethane-4,4'-dicarboxylate and the like can be preferably used.

The polyester film using the above polyester is preferably biaxially oriented. A biaxially oriented polyester film is generally an unstretched polyester sheet or film that is stretched about 2.5 to 5 times in the longitudinal direction and in the width direction perpendicular to the longitudinal direction, and then subjected to heat treatment to produce crystalline The alignment is completed, and it indicates a biaxial alignment pattern by wide-angle X-ray diffraction. When the polyester film is biaxially oriented, thermal stability, particularly dimensional stability and mechanical strength are sufficient, and flatness is also good.

In the polyester film, various additives such as antioxidants, heat stabilizers, weathering stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, antistatic agents. An agent, a nucleating agent, etc. may be added to such an extent that the properties are not deteriorated.

The thickness of the polyester film is not particularly limited and is appropriately selected depending on the use and type, but is preferably 10 to 500 μm, more preferably 15 to 250 μm, from the viewpoint of mechanical strength, handling properties, and the like. Most preferably, the thickness is 20 to 100 μm. The polyester film may be a composite film obtained by coextrusion or a film obtained by bonding the obtained film by various methods.

[Production method of resin layer]
Examples of the method for producing the resin layer of the laminated film of the present invention are shown below, but the materials, amounts used, ratios, treatment details, treatment procedures, etc. shown below may be changed as appropriate without departing from the spirit of the present invention. it can. Therefore, the scope of the present invention should not be construed as being limited by the examples shown below.

When the resin layer of the present invention contains the metal oxide particles (A), the π-electron conjugated polymer (B), the epoxy compound (C), and the acrylic resin (D), the reflectance at a wavelength of 550 nm. This is preferable because the amount of change in surface energy before and after the boiling test can be reduced.

In the resin layer, (A) to (D) may each include a plurality of types. If necessary, other compounds than (B) to (D), for example, the above-described ion conductive compounds (E), carbodiimide compounds, oxazoline compounds, aziridine compounds, titanium chelates and other titanate couplings Agents, methylolated or alkylolated melamine compounds, acrylamide compounds, and the like.

Further, various additives such as organic lubricants, organic or inorganic fine particles, antistatic agents, etc. may be added to such an extent that the characteristics are not deteriorated.

A resin composition using an aqueous solvent is prepared by adding at least water-dispersed or water-soluble acrylic resin (D) and metal oxide particles (A) in the order of (A) and (D), and once dispersing, After the acrylic resin (D) is adsorbed on the surface of the oxide particles (A), the π-electron conjugated polymer (B) and the epoxy compound (C) are added, and the aqueous solvent is mixed in a desired weight ratio. It can be prepared by stirring. Next, various additives (easily lubricants, inorganic particles, organic particles, surfactants, antioxidants, etc.) can be prepared by mixing and stirring the resin composition in a desired weight ratio as necessary. it can.

[Method for forming resin layer and method for producing laminated film]
The method for forming the resin layer of the laminated film of the present invention will be described below with reference to examples. However, the following materials, amounts used, ratios, processing details, processing procedures, and the like are appropriately changed without departing from the spirit of the present invention. can do. Therefore, the scope of the present invention should not be construed as being limited by the examples shown below.

The resin layer of the present invention comprises a resin composition containing metal oxide particles (A), a π-electron conjugated polymer compound (B), an epoxy compound (C), and an acrylic resin (D) on a polyester film. When the resin composition contains a solvent, the resin layer can be formed on the polyester film by drying the solvent.

In the present invention, when a solvent is included in the resin composition, an aqueous solvent is preferably used as the solvent. This is because the use of the aqueous solvent can suppress the rapid evaporation of the solvent in the drying step and can form a uniform composition layer, and is excellent in terms of environmental load.

Here, the aqueous solvent is soluble in water or water and alcohols such as methanol, ethanol, isopropyl alcohol and butanol, ketones such as acetone and methyl ethyl ketone, and glycols such as ethylene glycol, diethylene glycol and propylene glycol. Is an organic solvent mixed in an arbitrary ratio.

The method for applying the resin composition to the polyester film is preferably an in-line coating method. The in-line coating method is a method of applying in the process of manufacturing a polyester film. Specifically, it refers to a method of coating at any stage from melt extrusion of a polyester resin to biaxial stretching followed by heat treatment and winding up, and is generally substantially non-obtainable after melt extrusion and rapid cooling. Crystalline unstretched (unoriented) polyester film (A film), then uniaxially stretched (uniaxially oriented) polyester film (B film) stretched in the longitudinal direction, or biaxially before heat treatment stretched further in the width direction It is applied to any one of stretched (biaxially oriented) polyester film (C film).

In the present invention, the resin composition is applied to the polyester film of any one of the A film and the B film before the crystal orientation is completed, and then the polyester film is stretched in a uniaxial direction or a biaxial direction. It is preferable to employ a method in which a heat treatment is performed at a temperature higher than the boiling point to complete the crystal orientation of the polyester film and a resin layer is provided. According to this method, the polyester film can be formed and the resin composition can be applied and dried (that is, the resin layer is formed) at the same time. Moreover, it is easy to make the thickness of the resin layer thinner in order to perform stretching after coating.

Among them, a method of applying a resin composition to a film (B film) uniaxially stretched in the longitudinal direction, then stretching in the width direction, and performing a heat treatment is excellent. After applying to an unstretched film, the stretching process is less than once compared to the method of biaxial stretching, so it is difficult to cause defects or cracks in the composition layer due to stretching, and a composition layer excellent in transparency and smoothness This is because it can be formed.

In the present invention, the resin layer is preferably provided by an inline coating method from the various advantages described above. Here, as a method for applying the resin composition to the polyester film, any known method such as a bar coating method, a reverse coating method, a gravure coating method, a die coating method, or a blade coating method can be used.

Therefore, the best method for forming a resin layer in the present invention is a method in which a resin composition using an aqueous solvent is applied on a polyester film using an in-line coating method, dried and heat-treated. More preferably, the resin composition is in-line coated on the uniaxially stretched B film. In the method for producing a laminated film of the present invention, drying can be carried out in a temperature range of 80 to 130 ° C. in order to complete the removal of the solvent of the resin composition. Further, the heat treatment can be performed in a temperature range of 160 to 240 ° C. in order to complete the crystal orientation of the polyester film and complete the thermosetting of the resin composition to complete the formation of the resin layer.

Further, the solid content concentration of the resin composition is preferably 10% by weight or less. By setting the solid content concentration to 10% by weight or less, a good coating property can be imparted to the resin composition, and a laminated film provided with a transparent and uniform composition layer can be produced.

The solid content concentration represents the ratio of the weight of the resin composition minus the weight of the solvent to the weight of the resin composition (that is, [solid content concentration] = [(of the resin composition Weight) − (weight of solvent)] / [weight of resin composition]).

Next, the method for producing a laminated film of the present invention will be described by taking as an example the case where a polyethylene terephthalate (hereinafter referred to as PET) film is used as the polyester film, but is not limited thereto. First, PET pellets are sufficiently vacuum-dried, then supplied to an extruder, melt extruded into a sheet at about 280 ° C., and cooled and solidified to produce an unstretched (unoriented) PET film (A film). This film is stretched 2.5 to 5.0 times in the longitudinal direction with a roll heated to 80 to 120 ° C. to obtain a uniaxially oriented PET film (B film). The resin composition of the present invention prepared at a predetermined concentration is applied to one side of the B film.

At this time, a surface treatment such as a corona discharge treatment may be performed on the coated surface of the PET film before coating. By performing surface treatment such as corona discharge treatment, the wettability of the resin composition to the PET film is improved, the resin composition is prevented from being repelled, and a resin layer having a uniform coating thickness can be formed. After coating, the edge of the PET film is held with a clip and guided to a heat treatment zone (preheating zone) of 80 to 130 ° C., and the solvent of the resin composition is dried. After drying, the film is stretched 1.1 to 5.0 times in the width direction. Subsequently, it is guided to a heat treatment zone (heat setting zone) at 160 to 240 ° C., and heat treatment is performed for 1 to 30 seconds to complete crystal orientation.

In this heat treatment step (heat setting step), a relaxation treatment of 3 to 15% may be performed in the width direction or the longitudinal direction as necessary. The laminated film thus obtained is a laminated film that is transparent and has antistatic properties and excellent interference spot suppression (visibility) when a high refractive index hard coat layer is laminated.

The thickness of the resin layer in the present invention is preferably 10 nm or more and 80 nm or less. More preferably, they are 10 nm or more and 50 nm or less, More preferably, they are 10 nm or more and 40 nm or less. By setting the thickness of the resin layer to 10 nm or more and 80 nm or less, it is possible to sufficiently exhibit interference spot suppression and antistatic properties.

[Characteristic measurement method and effect evaluation method]
The characteristic measurement method and effect evaluation method in the present invention are as follows.

(1) Haze, Transparency Haze is measured using a turbidimeter “NDH5000” manufactured by Nippon Denshoku Industries Co., Ltd. after standing for 40 hours in a normal state (23 ° C., relative humidity 50%). In accordance with JIS K 7136 “How to Determine Haze of Transparent Material” (2000 version). In addition, it measured by irradiating light from the surface side on which the resin layer of the sample was laminated. Ten samples each having a square with a side of 50 mm were prepared, and the average value obtained by measuring once each 10 times in total was used as the haze value of the sample.
Further, the transparency was evaluated by a four-step evaluation based on the haze value. C is a practically problematic level, B is a practical level, and A and S are good.
S: 0.6% or less A: Over 0.6% and 1.0% or less B: Over 1.0% and 1.5% or less C: Over 1.5%

(2) Reflectance The film sheet cut into A4 cut size was divided into 3 parts each in length and width, and a total of 9 points were used as measurement samples. The long side was defined as the longitudinal direction. Spectral reflectance is measured with a 50 mm wide black glossy tape (manufactured by Yamato Co., Ltd., vinyl tape No. 200-50-21: black) on the back surface of the measurement surface (the resin layer), and does not bite the bubbles. After attaching the sample and the tape in the longitudinal direction, the sample was cut into about 4 cm square sample pieces, and the spectral reflectance at an incident angle of 5 ° was measured with a spectrophotometer (manufactured by Shimadzu Corporation, UV2450). did. The direction in which the sample was set in the measuring instrument was adjusted to match the longitudinal direction of the sample in the front-rear direction toward the front of the measuring instrument. In order to standardize the reflectance, an attached Al ₂ O ₃ plate was used as a standard reflecting plate. For the reflectance, the reflectance on the resin layer side at a wavelength of 550 nm was determined. In addition, the average value of 10 points | pieces was used for the measured value.

(3) Adhesiveness to the laminate (3-1) Initial adhesiveness The UV curable resin mixed at the following ratio on the resin layer side of the laminated film has a thickness of 2 μm after curing using a bar coater. It applied uniformly so that it might become.
<Adjustment of hard coating agent>
Titanium dioxide fine particles (Ishihara Sangyo Co., Ltd., TTO-55B): 30 parts by weightCarboxylic acid group-containing monomer (Toa Gosei Co., Ltd., Aronix M-5300): 4.5 parts by weightCyclohexanone: 65. 5 parts by weight The above mixture was dispersed by a sand grinder mill to prepare a dispersion of fine titanium dioxide particles having an average particle diameter of 55 nm.

Dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd., DPHA) and photoinitiator (manufactured by Ciba Geigy Co., Ltd., Irgacure 184) are added to the above-mentioned dispersion of titanium dioxide fine particles and dipentaerythritol hexaacrylate is 100 weights. 5% by weight was added to the part and mixed to adjust the refractive index of the hard coat layer to 1.65.
Next, the integrated irradiation intensity was set with a concentrating high-pressure mercury lamp (I03, H03-L31) having an irradiation intensity of 120 W / cm set at a height of 9 cm from the surface on which the UV curable resin layer was laminated. The hard coat laminated polyester film in which the hard coat layer was laminated on the laminated polyester film was obtained by irradiating and curing ultraviolet rays so as to be 300 mJ / cm ² . In addition, an industrial UV checker (manufactured by Nippon Batteries Co., Ltd., UVR-N1) was used for measuring the cumulative irradiation intensity of ultraviolet rays. About the obtained hard coat laminated polyester film, 100 crosscuts of 1 mm ² were put on the hard coat laminated surface of the obtained hard coat laminated polyester film, and “Cello Tape” (registered trademark) (manufactured by Nichiban Co., Ltd., CT405AP). ) And pressed with a hand roller at a load of 1.5 kg / cm ² , and then rapidly peeled in the direction of 90 degrees with respect to the hard coat laminated polyester film. Adhesiveness was evaluated in four stages according to the number of remaining lattices. The evaluation was performed using an average value obtained 10 times. C is a practically problematic level, B is a practical level, and A and S are good.
S: 90 to 100 remaining A: 80 to 89 remaining B: 50 to 79 remaining C: 0 to less than 50 remaining.

(3-2) Wet heat adhesiveness (3-1) After obtaining a hard-coated laminated polyester film in the same manner as the initial adhesiveness, it was stored in a high temperature and high humidity environment (temperature 85 ° C., relative humidity 85%) for 240 hours, A hard coat laminated polyester film after wet heat treatment was obtained. About the hard coat laminated polyester film after the wet heat treatment, 100 cross cuts of 1 mm ² were put on the hard coat laminated surface of the hard coat laminated polyester film, and “Cello Tape” (registered trademark) (manufactured by Nichiban Co., Ltd., CT405AP) Was pressed with a load of 1.5 kg / cm ² with a hand roller, and then rapidly peeled in the direction of 90 degrees with respect to the hard coat laminated polyester film. Adhesiveness was evaluated in four stages according to the number of remaining lattices. The evaluation was performed using an average value obtained 10 times. C is a practically problematic level, B is a practical level, and A and S are good.
S: 90 to 100 remaining A: 80 to 89 remaining B: 50 to 79 remaining C: 0 to less than 50 remaining.

(4) Antistatic property (surface resistivity)
The antistatic property was measured by the surface specific resistance value. The measurement of the surface resistivity value was allowed to stand for 24 hours at a relative humidity of 23%, and in that atmosphere, a digital ultrahigh resistance / microammeter R8340A (manufactured by Advantest Co., Ltd.) was used. Measurements were made. The unit is Ω / □. The resin laminated surface of the laminated sample was evaluated, and the average value measured 10 times in total was taken as the surface specific resistance value (R1) of the sample.
1 × ^{10 11} Ω / □ or less is good, 1 × ^{10 12} Ω / □ or less is practically level, 1 × ^{10 12} Ω / □ when it exceeds was level with practical problems.

(5) Number average particle diameter The number average particle diameter of the metal oxide particles (A) was determined by observing the cross-sectional structure of the laminated film with a transmission electron microscope (TEM). The magnification was set to 500,000, and the outer diameter of 10 particles existing in the screen was measured for a total of 100 particles for 10 fields of view, and the average particle size was determined. When 10 particles do not exist in the screen, observe another part under the same conditions, measure the outer diameter of the particles present in the screen, and measure the outer diameter of 100 particles in total. Averaged. Here, the outer diameter means the maximum diameter of the particle (that is, the longest diameter of the particle and indicates the longest diameter in the particle). Similarly, in the case of a particle having a cavity inside, the maximum diameter of the particle is also defined. To express.

(6) Film thickness of resin layer The thickness of the resin layer on a polyester film was measured by observing a cross section using a transmission electron microscope (TEM). As for the thickness of the resin layer, the thickness of the resin layer was read from an image taken with a TEM at a magnification of 200,000 times. A total of 20 resin layer thicknesses were measured and taken as an average value.

(7) Interference unevenness suppression property By the method similar to (3), the hard-coat laminated polyester film by which the hard-coat layer (refractive index 1.65) of thickness 2 micrometers was laminated | stacked on the laminated polyester film was obtained.
Next, a sample having a size of 8 cm (laminated polyester film width direction) × 10 cm (laminated polyester film longitudinal direction) was cut out from the obtained optical laminated film, and a black glossy tape (Yamato Co., Ltd.) was formed on the opposite surface of the hard coat layer. ) And vinyl tape No. 200-50-21 (black) were bonded together so as not to bite the bubbles.
Place this sample in a dark room 30 cm directly under a 3-wavelength fluorescent lamp (manufactured by Panasonic Corporation, 3-wavelength daylight white (F · L 15EX-N 15W)), and visually observe the degree of interference spots while changing the viewing angle. The following evaluation was performed. A or higher was considered good.
S: Interference spots are almost invisible A: Interference spots are slightly visible B: Weak interference spots are visible
C: Interference spots are strong.

(8) Boiling treatment test A laminated film sample was cut into a size of 10 cm x 10 cm to obtain a reflectance evaluation sample after the boiling treatment test. The sample was fixed to a clip and suspended, and then placed in boiling water (100 ° C.) made of pure water prepared in a beaker for 2 hours with the entire laminated film immersed. After that, the reflectance evaluation sample after the boiling treatment test was taken out, dried at an air volume of 1 m / min for 30 minutes, moisture was removed, dried in a normal state (23 ° C., relative humidity 65%) for 12 hours, and after the boiling treatment test. A sample for reflectance evaluation was obtained.

(9) Change amount of surface energy Δγ of resin layer before and after boiling test
(9-1) Method for calculating surface energy The laminated film was allowed to stand for 24 hours in an atmosphere having a room temperature of 23 ° C. and a relative humidity of 65%. Thereafter, the contact angle of each of the four types of solutions of pure water, ethylene glycol, formamide, and diiodomethane with respect to the resin layer (X) side surface of the laminated film under the same atmosphere is a contact angle meter CA-D type ( 5 points each by Kyowa Interface Science Co., Ltd. The average value of the three measured values excluding the maximum value and the minimum value of the five measured values is defined as the contact angle of each solution.

Next, using the contact angles of the four types of solutions obtained, “the surface free energy (γ) of the solid, which is proposed by Hata et al., Is expressed as a dispersion force component (γ _S ^d ) and a polar force component (γ _S ^p ). , And the hydrogen bonding force component (γ _S ^h ), and the geometric mean method based on the formula (expanded Fowkes formula) obtained by extending the Fowkes formula, The surface energy that is the sum of the polar forces is calculated.

A specific calculation method is shown. The meaning of each symbol is described below. When γ _S ^L is the tension at the interface between the solid and the liquid, Equation (1) is established.

γ _S ^L : surface free energy of resin layer (X) and known solutions listed in Table 1 γ _S : surface free energy of resin layer (X) γ _L : surface free energy of known solutions listed in Table 1 γ _S ^d : Dispersion force component of surface free energy of resin layer (X) γ _S ^p : Polar force component of surface free energy of resin layer (X) γ _S ^h : Hydrogen bond strength of surface free energy of resin layer (X) Component γ _L ^d : Dispersion force component of the surface free energy of the known solution described in Table 1 γ _L ^p : Polar force component of the surface free energy of the known solution described in Table 1 γ _L ^h : As described in Table 1 Hydrogen bonding force component of the surface free energy of the known solution γ _S ^L = γ _S + γ _L -2 (γ _S ^d · γ _L ^d ) ^1/2 -2 (γ _S ^p · γ _L ^p ) ^1/2 -2 ^{_{(γ S h · γ L h}} ) 1/2 ··· equation (1).

Also, the state when the smooth solid surface is in contact with the liquid droplet at the contact angle (θ) is expressed by the following equation (Young's equation).

γ _S = γ _S ^L + γ _L cos θ (2)

When these mathematical formulas (1) and (2) are combined, the following formula is obtained.
_{^{(γ S d · γ L d}} ) 1/2 + (γ S p · γ L p) 1/2 + (γ S h · γ L h) 1/2 = γ L (1 + cosθ) / 2 ··· formula (3).

Actually, the four components of water, ethylene glycol, formamide, and diiodomethane have contact angles (θ) and the components of the surface tension of known solutions listed in Table 1 (γ _L ^d , γ _L ^p , γ _L ^h ) is substituted into Equation (3) to solve the four simultaneous equations. As a result, the surface free energy (γ) of the solid, that is, the surface free energy of the surface of the resin layer (X) is calculated.

(9-2) Surface energy change Δγ before and after boiling
Absolute value of the value obtained by subtracting the surface energy of the resin layer before the boiling treatment test from the surface energy of the resin layer after the boiling treatment test (Δγ = | surface energy of the resin layer after the boiling treatment test-resin layer before the boiling treatment test Surface energy |). The sample obtained according to the method of (8) was used as the sample for evaluation after the boiling treatment test. A or higher was considered good.
S: 3 mN / m or less A: Over 3 mN / m and 5 mN / m or less B: Over 5 mN / m and 7 mN / m or less C: Over 7 mN / m

(10) Surface roughness (arithmetic mean roughness: Ra)
The surface obtained by measuring the resin layer side of the laminated film with a measurement range of 10 μm × 10 μm, the number of measurement lines of 512, and the measurement rate of 1.0 Hz in the Scan Asist Air mode of the atomic force microscope “Dimension Icon Scan Asyst” manufactured by BRUKER From the information, the arithmetic average roughness (Ra) was calculated by the method defined in JIS-B-0601-1994. Specifically, “NanoScope Analysis” is used as software, “3rd” of “Flatten Order” is selected, and a three-dimensional swell process is performed. Thereafter, “Roughness” is selected, and the numerical value described in “Image Ra” on the screen is set as the arithmetic average roughness. In addition, measurement was made 10 times in total, and the average value of a total of 8 data excluding the maximum value and the minimum value was taken as the arithmetic average roughness (Ra) of the sample.
The arithmetic average roughness was evaluated in four stages. C is a practically problematic level, B is a practical level, and A and S are good.
S: 10 nm or less A: Over 10 nm and 15 nm or less B: Over 15 nm and 20 nm or less C: Over 20 nm

(11) Composition analysis of resin layer The composition analysis of the resin layer is performed on the surface of the laminated film by using an X-ray photoelectron spectrometer (ESCA), Fourier infrared spectrophotometer (FT-IR) ATR method, time-of-flight secondary An ion gravimetric analyzer (TOF-SIMS) was used. The resin layer is dissolved and extracted with a solvent and separated by chromatography, and then proton nuclear magnetic resonance spectroscopy ( ¹ H-NMR), carbon nuclear magnetic resonance spectroscopy ( ¹³ C-NMR), Fourier infrared spectroscopy. The structure was analyzed with a photometer (FT-IR), and the composition of the resin layer was analyzed by pyrolysis gas chromatography gravimetric analysis (GC-MS). By the above method, the presence or absence of metal oxide particles (A), π-electron conjugated polymer compound (B), epoxy compound (C), acrylic resin (D), and ion conductive compound (E) in the resin layer is confirmed. did. In the resin layer, when the said compound was contained, it was set to A, and when not containing, it was set to B.

(12) Antistatic property (surface specific resistance value) after laminating high refractive index hard coat
By the same method as (3), a hard coat laminated polyester film in which a hard coat layer (refractive index of 1.65) having a thickness of 2 μm was laminated on the laminated polyester film was obtained. The surface specific resistance value of the hard coat layer surface of the hard coat laminated polyester film was measured. The surface specific resistance value was measured by the method described in (4), and the average value measured five times in total was used as the surface specific resistance value of the sample, and B or higher was determined as good.
A: 1 × 10 ¹² Ω / □ or less B: 1 × 10 ¹² Ω / □ or less, 1 × 10 ¹³ Ω / □ or less C: 1 × 10 ¹³ Ω / □ or less A: Good, B P is a practical level, and C is a practically problematic level.

(13) Antistatic property (charge amount) after high refractive index hard coat lamination
The same UV curable resin as that used for (3-1) initial adhesion is uniformly applied to the resin layer side of the laminated film using a bar coater so that the film thickness after curing is 2 μm. The film roll which wound up in the shape and wound up the hard-coat laminated film was obtained. Then, the potential of the hard coat layer surface was measured at a position 5 cm away from the winding surface when the wound hard coat laminated film roll was wound. The charge amount was measured using STATIDON TYPE-TH manufactured by Sicid Electric Co., Ltd., and the average value measured five times in total was used as the charge amount of the sample.
A: Absolute value of potential is 2 kV or less B: Absolute value of potential exceeds 2 kV, and 5 kV or less C: Absolute value of potential exceeds 5 kV

Reference Example 1 π electron conjugated polymer compound (B-1)
7. In 1887 parts by weight of an aqueous solution containing 20.8 parts by weight of polystyrene sulfonic acid which is an acidic polymer compound, 49 parts by weight of a 1% by weight iron (III) sulfate aqueous solution and 3,4-ethylenedioxythiophene which is a thiophene compound 8 parts by weight and 117 parts by weight of a 10.9% by weight aqueous peroxodisulfuric acid solution were added. The mixture was stirred at 18 ° C. for 23 hours. Next, 154 parts by weight of a cation exchange resin and 232 parts by weight of an anion exchange resin were added to this mixture, and the mixture was stirred for 2 hours. Then, the ion exchange resin was filtered off to obtain poly (3,4-ethylenedioxythiophene). ) And polystyrene sulfonic acid in an aqueous dispersion (solid content concentration: 1.3% by weight).

Reference Example 2 Preparation of Mixture (AD) of Metal Oxide Particles (A) and Acrylic Resin (D) Isopropyl alcohol 100 as a solvent in a normal acrylic resin reaction vessel equipped with a stirrer, thermometer and reflux condenser. The parts were charged and heated to 100 ° C. with stirring. In this, 40 parts of nonadecyl methacrylate of n = 19 as (meth) acrylate (d1 ′), 40 parts of isobornyl methacrylate having two rings as (meth) acrylate (d2 ′), and a carboxyl group As (meth) acrylate (d3 ′), a mixture of 20 parts of methacrylic acid was added dropwise over 3 hours. Then, after completion of the dropwise addition, the mixture was heated at 100 ° C. for 1 hour, and then an additional catalyst mixture composed of 1 part of t-butylperoxy 2-ethylhexaate was charged. Next, the mixture was heated at 100 ° C. for 3 hours and then cooled to obtain an acrylic resin (D).

Next, an aqueous dispersion of zirconium oxide particles (A) (zirconium oxide dispersion SZR-CW manufactured by Sakai Chemical Industry Co., Ltd., zirconium oxide number average particle diameter 20 nm) and an acrylic resin (D ) Were added in order and dispersed by the following method to obtain a mixture of particles (A) and acrylic resin (D). (Method (ii) above) The addition ratio (weight ratio) of the metal oxide particles (A) and the acrylic resin (D) was (A) / (D) = 100/20 (note that the weight ratio was And rounded to the first decimal place). The dispersion treatment was performed by using a homomixer and rotating at a peripheral speed of 10 m / s for 5 hours. Further, the weight ratio of the particles (A) to the acrylic resin (D) in the finally obtained mixture was (A) / (D) = 100/20 (note that the weight ratio is the first decimal place). Calculated by rounding off the decimal place).

The obtained particles (AD) were centrifuged using a Hitachi tabletop ultracentrifuge (manufactured by Hitachi Koki Co., Ltd .: CS150NX) (rotation speed: 3,000 rpm, separation time: 30 minutes) to obtain metal oxide particles ( After A) (and the acrylic resin (D) adsorbed on the surface of the metal oxide particles (A)) was allowed to settle, the supernatant was removed and the precipitate was concentrated to dryness. As a result of analyzing the concentrated and solidified sediment by X-ray photoelectron spectroscopy (XPS), it was confirmed that the acrylic resin (D) was present on the surface of the metal oxide particles (A). That is, the acrylic resin (D) is adsorbed and adhered to the surface of the metal oxide particles (A), and the obtained particles (AD) are adhered to the surface of the metal oxide particles (A). It was found to fall under the category of particles having

Reference Example 3 Preparation of an ion conductive compound (polystyrene sulfonate lithium salt (E-1) In a nitrogen gas atmosphere and at room temperature (25 ° C.), 200 parts by weight of water and 1 part by weight of ammonium persulfate were placed in a container 1. The solution was heated to 85 ° C. and dissolved to obtain a solution 1 at 85 ° C.

Under normal temperature (25 ° C.), 100 parts by weight of lithium styrenesulfonate, 3 parts by weight of ammonium persulfate and 100 parts of water were added to the container 2 to obtain a solution 2.

In a nitrogen gas atmosphere, the solution 1 was transferred to the reactor, and the solution 2 was continuously added dropwise to the solution 1 over 4 hours while maintaining the temperature of the solution in the reactor at 85 ° C. After completion of the dropwise addition, the mixture was further stirred for 3 hours and then cooled to 25 ° C. to obtain polystyrene sulfonate lithium salt (E-1).

Tables 1 to 4 show the characteristics of the laminated films obtained in the following examples and comparative examples.

<Example 1>
First, the resin composition 1 was prepared as follows.
<Resin composition>
To the aqueous solvent, the above particles (A), acrylic resin (D), π-electron conjugated polymer compound (B) and epoxy compound (C) are added in this order, and mixed in the ratios shown in Table 1, to obtain a resin. A composition was obtained.
・ A mixture of particles (A) and acrylic resin (D) (AD)
・ Π-electron conjugated polymer (B)
Epoxy compound (C): Polyglycerol polyglycidyl ether type epoxy cross-linking agent (Nagase Chemtech Co., Ltd. "Denacol (registered trademark)" EX-512 (molecular weight 630, epoxy equivalent 168, water solubility 100%)
<Laminated film>
Next, PET pellets (intrinsic viscosity 0.63 dl / g) substantially free of particles were sufficiently dried in vacuum, then supplied to an extruder, melted at 285 ° C., extruded into a sheet form from a T-shaped die, It was wound around a mirror-casting drum having a surface temperature of 25 ° C. using an electric application casting method and cooled and solidified. This unstretched film was heated to 90 ° C. and stretched 3.4 times in the longitudinal direction to obtain a uniaxially stretched film (B film).

Next, the resin composition 1 was applied to the corona discharge-treated surface of the uniaxially stretched film with a coating thickness of about 6 μm using a bar coat. The both ends in the width direction of the uniaxially stretched film coated with the resin composition are gripped with clips and guided to a preheating zone, and the ambient temperature is set to 75 ° C. Subsequently, the ambient temperature is set to 110 ° C using a radiation heater, and then the ambient temperature. The resin composition was dried at 90 ° C. to form a resin layer. Continuously stretched 3.5 times in the width direction in a heating zone (stretching zone) at 120 ° C, and then heat treated for 20 seconds in a heat treatment zone (heat setting zone) at 230 ° C to complete the crystal orientation. Got. In the obtained laminated film, the thickness of the PET film was 100 μm, and the thickness of the resin layer was about 0.02 μm.
Table 3 shows the characteristics and the like of the obtained laminated film.
The haze was low, the reflectivity was high, the amount of surface energy change and the surface specific resistance value were small, and the transparency, interference spot suppression, adhesion, and antistatic properties were excellent.

<Examples 2 to 12>
A laminated film was obtained in the same manner as in Example 1 except that the ratio of the resin composition in the coating liquid was changed as shown in Table 1.
Table 1 shows the characteristics of the obtained laminated film.

<Examples 13 to 16>
Example 1 except that the number average particle size of the metal oxide particles (A) was changed to 3 nm (Example 13), 15 nm (Example 14), 30 nm (Example 15), and 50 nm (Example 16). A laminated film was obtained in the same manner. Table 1 shows the characteristics of the obtained laminated film.

<Example 17>
Except for changing the metal oxide particles (A) to titanium oxide particles “NanoTek” (registered trademark) TiO ₂ slurry (CI Chemical Co., Ltd., number average particle size 20 nm), the same method as in Example 1 was used. A laminated film was obtained. Table 1 shows the characteristics of the obtained laminated film.

<Examples 18 to 20>
The metal oxide particles (A) are zinc oxide particles FINEX-50 (manufactured by Sakai Chemical Industry Co., Ltd., number average particle diameter 20 nm) (Example 18), ITO slurry (manufactured by CII Kasei Co., Ltd., number average particles) 20 nm) (Example 19), except that it was changed to “NanoTek” (registered trademark) Y ₂ O ₃ slurry (Cai Kasei Co., Ltd., number average particle size 20 nm) (Example 20), which is yttrium oxide. A laminated film was obtained in the same manner as in Example 1. Table 1 shows the characteristics of the obtained laminated film.

<Examples 21 to 23>
A laminated film was obtained in the same manner as in Example 1 except that the thickness of the resin layer was changed to 10 nm (Example 21), 30 nm (Example 22), and 50 nm (Example 23). Table 1 shows the characteristics of the obtained laminated film.

<Example 24>
The (meth) acrylate monomer (d3 ′) was changed to N, N-dimethylaminoethyl methacrylate having a tertiary amino group (the R ₃ group of the monomer unit represented by the formula (3) has no carboxyl group) A laminated film was obtained in the same manner as in Example 1 except that the acrylic resin was used. Table 1 shows the characteristics of the obtained laminated film.

<Example 25>
The acrylic resin (D) was changed to an acrylic resin (manufactured by Nippon Carbide Corporation, RX7013ED) (a monomer unit represented by the formula (1) and an acrylic having no monomer unit represented by the formula (2). A laminated film was obtained in the same manner as in Example 1 except that the resin was used. Table 1 shows the characteristics of the obtained laminated film.

<Example 26>
A laminated film was obtained in the same manner as in Example 1 except that zirconia chelate (Matsumoto Fine Chemical “Orgachix” (registered trademark) ZC300) was used instead of the metal oxide particles (A). Table 1 shows the characteristics of the obtained laminated film.

<Example 27>
A laminated film in the same manner as in Example 1 except that an ionic conductive compound (ammonium salt) (manufactured by ADEKA, Adeka Cioace PD50) was used instead of the π-electron conjugated polymer compound (B). Got. Table 1 shows the characteristics of the obtained laminated film.

<Example 28>
A laminated film was obtained in the same manner as in Example 1 except that the ion conductive compound (lithium styrene sulfonate) (E-1) was used instead of the π electron conjugated polymer compound (B). Table 1 shows the characteristics of the obtained laminated film.

<Comparative Example 1>
Example 1 except that the metal oxide particles (A) in Example 1 were changed to “Snowtex” (registered trademark) CM (manufactured by Nissan Chemical Industries, Ltd., number average particle diameter 20 nm), which is silica particles. A laminated film was obtained in the same manner. Table 1 shows the characteristics of the obtained laminated film.

<Comparative Examples 2-3>
The metal oxide particles (A) in Example 1 are made of MgF ₂ particles, “NanoTek” (registered trademark) MgF ₂ slurry (manufactured by CI Kasei Co., Ltd., number average particle size 20 nm) (Comparative Example 2), hollow A laminated film was obtained in the same manner as in Example 1, except that the silica particles were changed to “Thruria” (registered trademark) TR112 (manufactured by JGC Catalysts & Chemicals Co., Ltd., number average particle diameter 20 nm) (Comparative Example 3). It was. Table 1 shows the characteristics of the obtained laminated film.

<Comparative example 4>
A laminated film was obtained in the same manner as in Example 1 except that the π-electron conjugated polymer compound (B) in Example 1 was not used. Compared with Example 1, although the surface specific resistance value was high and showed the same transparency, visibility, and adhesion to the laminate, it was lacking in antistatic properties.

<Comparative Example 5>
A laminated film was obtained in the same manner as in Example 1 except that a polyester resin (manufactured by Takamatsu Yushi Co., Ltd., Pes Resin A110) was used instead of the epoxy compound (C) in Example 1. Compared with Example 1, by using a polyester resin, the change of the surface energy after a boiling process was large, and the wet heat adhesiveness was lacking.

<Comparative Example 6>
A laminated film was obtained in the same manner as in Example 1 except that the acrylic resin (D) in Example 1 was not used. Compared with Example 1, by not using an acrylic resin, the change of the surface energy after a boiling process was large, and the wet heat adhesiveness was lacking.

<Comparative Example 7>
A laminated film was obtained in the same manner as in Example 1 except that the thickness of the resin layer in Example 1 was 7 nm. Compared with Example 1, although the surface specific resistance value was high and showed the same transparency, visibility, and adhesion to the laminate, it was lacking in antistatic properties.

The present invention is a laminate having transparency, high interference refractive index suppression when laminating a high refractive index hard coat layer, excellent adhesion to the high refractive index hard coat layer, and high antistatic properties regardless of humidity. The present invention relates to a film, and can be used as an optically easily adhesive film for display applications.

Claims (10)

1. A laminated film in which a resin layer is provided on at least one side of a polyester film, the reflectance of the resin layer surface at a wavelength of 550 nm is 6.0% or more, and the surface specific resistance value of the resin layer surface is 10 ¹² Ω. / □ or less, and the surface energy change Δγ before and after the boiling test on the surface of the resin layer (Δγ = | the surface energy of the resin layer after the boiling treatment test−the surface energy of the resin layer before the boiling treatment test |) is 5 mN / A laminated film characterized by being m or less.
2. The arithmetic average roughness (Ra) of the surface of the resin layer is 20 nm or less, and the laminated film according to claim 1.
3. The resin layer contains metal oxide particles (A) having a number average particle diameter of 3 nm or more and 50 nm or less, a π-electron conjugated polymer compound (B), an epoxy compound (C), and an acrylic resin (D). The laminated film according to claim 1 or 2, wherein:
4. 4. The laminated film according to claim 3, wherein the content of the metal oxide particles (A) in the resin layer is 30% by weight or more and 90% by weight or less with respect to the entire resin layer.
5. The content of the epoxy compound (C) in the resin layer is 20 to 60 parts by weight when the content of the metal oxide particles (A) in the resin layer is 100 parts by weight. The laminated film according to 3 or 4.
6. The laminated film according to any one of claims 3 to 5, wherein the metal oxide particles (A) are particles having the acrylic resin (D) on a surface thereof.
7. The laminated film according to any one of claims 3 to 6, wherein the metal oxide particles (A) are titanium oxide particles (A ₁ ') and / or zirconium oxide particles (A ₂ ').
8. The acrylic resin (D) comprises a monomer unit (d1) represented by formula (1), a monomer unit (d2) represented by formula (2), and a monomer unit (d3 represented by formula (3)). The laminated film according to any one of claims 3 to 7, wherein the laminated film is a resin having).
   

   

   (In Formula (1), R ₁ group represents a hydrogen atom or a methyl group. Further, n represents an integer of 9 or more and 34 or less.)
   

   

   (In the formula (2), the R ₂ group represents a hydrogen atom or a methyl group. The R ₄ group represents a group containing two or more saturated carbocycles.)
   

   

   (In the formula (3), the R ₃ group represents a hydrogen atom or a methyl group. The R ₅ group represents a hydroxyl group, a carboxyl group, a tertiary amino group, a quaternary ammonium base, a sulfonic acid group, or phosphoric acid. Represents a group.)
9. The laminated film according to any one of claims 1 to 8, wherein the resin layer has a thickness of 10 to 80 nm.
10. A method for producing a laminated film in which a resin layer is provided on at least one side of a polyester film,
    The resin layer contains metal oxide particles (A) having a number average particle diameter of 3 nm or more and 50 nm or less, a π-electron conjugated polymer compound (B), an epoxy compound (C), and an acrylic resin (D). After applying the resin composition to at least one side of the polyester film, it is a layer formed by drying,
    The content of the epoxy compound (C) in the resin composition is 20 to 60 parts by weight when the content of the metal oxide particles (A) in the resin composition is 100 parts by weight. A method for producing a laminated film.