JP2001328195A - Functional film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a functional film which is prepared by a coating method and can exert various functions and which has a transparent conductive layer having a low electric resistance value, for instance, and is excellent in flatness in particular. SOLUTION: The functional film 1 has a compressed layer 3 of functional particulates on the substrate 2. The thickness tS of the substrate and the thickness tF of the compressed layer are in the relation of tS/tF>=25. The compressed layer of the functional particulates is obtained by a process wherein a liquid wherein the functional particulates are dispersed is applied on the substrate and dried and a functional particulate containing layer thus formed is compressed. The dispersion liquid contains no resin, or contains a resin of a volume less than 25 in relation to 100 of the volume of the functional particulates when they are expressed by the volumes before the dispersion. The substrate is preferably a film made of resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a functional film having a functional layer formed on a support. In the present invention, the film includes both a film and a sheet.
The functional layer is a layer having a function, and the function means a function performed through physical and / or chemical phenomena. The functional layer includes a conductive layer, a magnetic layer, a ferromagnetic layer, a dielectric layer, a ferroelectric layer, an electrochromic layer, an electroluminescent layer, an insulating layer, a light absorption layer, a light selective absorption layer,
Films having various functions such as a reflection layer, an antireflection layer, a catalyst layer, and a photocatalyst layer are included.

When conductive fine particles are used as the functional fine particles, a conductive film having a transparent conductive layer can be obtained. The transparent conductive layer can be used as a transparent electrode such as an electroluminescence panel electrode, an electrochromic device electrode, a liquid crystal electrode, a transparent surface heating element, and a touch panel, and can also be used as a transparent electromagnetic wave shielding layer.

[0003]

2. Description of the Related Art Conventionally, functional layers made of various functional materials have been formed by physical vapor deposition (PVD) such as vacuum evaporation, laser ablation, sputtering, ion plating, thermal CVD, photo CVD, and the like. It is manufactured by chemical vapor deposition (CVD) such as plasma CVD. These generally require a large-scale apparatus, and some of them are not suitable for forming a large-area film.

[0004] Further, formation of a film by coating using a sol-gel method is also known. The sol-gel method is also suitable for forming a large-area film, but often requires sintering the inorganic material at a high temperature after coating.

For example, a transparent conductive layer is as follows. At present, transparent conductive layers are mainly manufactured by a sputtering method. There are various methods of sputtering, for example, accelerated collision of inert gas ions generated by direct current or high-frequency discharge in a vacuum onto the target surface, and strike out atoms constituting the target from the surface,
This is a method of forming a film by depositing it on the substrate surface. The sputtering method is excellent in that a conductive layer having a low surface electric resistance can be formed even with a relatively large area. However, there is a disadvantage that the apparatus is large and the film forming speed is low. As the area of the conductive layer is further increased in the future, the size of the device will be further increased. This technically causes problems such as the necessity of increasing control accuracy, and another problem arises that manufacturing costs increase.
Further, the number of targets is increased to compensate for the low film formation speed, and the speed is increased. However, this also causes a problem in that the size of the apparatus is increased.

[0006] Production of a transparent conductive layer by a coating method has also been attempted. In a conventional coating method, a conductive paint in which conductive fine particles are dispersed in a binder solution is applied on a substrate, dried, and cured to form a conductive layer. The coating method has the advantages that a large-area conductive layer can be easily formed, the apparatus is simple and the productivity is high, and the conductive layer can be manufactured at lower cost than the sputtering method. In the coating method, the conductive fine particles come into contact with each other to form an electric path, thereby exhibiting conductivity. However, the conductive layer produced by the conventional coating method has a defect that the contact is insufficient and the obtained conductive layer has a high electric resistance value (inferior in conductivity), and its use is limited.

As a method for producing a transparent conductive layer by a conventional coating method, for example, Japanese Patent Application Laid-Open No. 9-109259 discloses that a paint comprising a conductive powder and a binder resin is coated on a transfer plastic film, dried, and dried. First step of forming a layer, pressurizing the conductive layer surface to a smooth surface (5 to 100 kg /
cm ² ), a second step of heating (70 to 180 ° C.)
A production method comprising a third step of laminating this conductive layer on a plastic film or sheet and thermocompression bonding is disclosed. In this method, a large amount of binder resin is used (in the case of inorganic conductive powder, binder 1 is used).
100 parts by weight, 100 to 500 parts by weight of conductive powder, and in the case of organic conductive powder, 0.1 to 30 parts by weight of conductive powder with respect to 100 parts by weight of binder)
A transparent conductive layer having a low electric resistance value cannot be obtained.

For example, Japanese Patent Application Laid-Open No. 8-199096 discloses a method for forming a binder-free conductive film comprising tin-doped indium oxide (ITO) powder, a solvent, a coupling agent, and an organic or inorganic acid salt of a metal. A method is disclosed in which a paint is applied to a glass plate and fired at a temperature of 300 ° C. or higher. In this method, since no binder is used, the electric resistance value of the conductive layer is low. But 300 ° C
Since it is necessary to perform the firing step at the above temperature, it is difficult to form a conductive layer on a support such as a resin film. That is, the resin film is melted, carbonized, or burned by the high temperature. Depending on the type of resin film, for example, polyethylene terephthalate (P
For ET) films, a temperature of 130 ° C. would be the limit.

As a method other than the coating method, see Japanese Patent Application Laid-Open No.
Japanese Patent No. 3785 discloses a powder compression layer in which at least a part, preferably all of the voids of a skeleton structure composed of a conductive substance (metal or alloy) powder is filled with a resin, and a resin under the powder compressed layer. A conductive coating comprising a layer is disclosed.
The production method will be described by taking a case where a film is formed on a plate material as an example. According to the publication, first, a resin, a powdery substance (metal or alloy) and a plate material to be processed are vibrated or agitated in a container together with a film forming medium (steel balls having a diameter of several mm). A resin layer is formed on the surface. Subsequently, the powder material is captured and fixed to the resin layer by the adhesive force of the resin layer. Further, the vibrating or agitating film-forming medium exerts a striking force on the vibrating or agitating powder material to form a powder compaction layer. A significant amount of resin is required to obtain the effect of fixing the powder compression layer. Further, the production method is more complicated than the coating method.

[0010] As a method other than the coating method, see JP-A-9-19-1
JP-A-07195 discloses a method in which conductive short fibers are sprinkled and deposited on a film such as PVC, and this is subjected to a pressure treatment to form a conductive fiber-resin integrated layer. The conductive short fiber is a short fiber such as polyethylene terephthalate, which is coated with nickel plating or the like. The pressing operation is preferably performed under a temperature condition at which the resin matrix layer shows thermoplasticity.
High temperature and low pressure conditions of g / cm ² are disclosed.

[0011]

From such a background,
A large-area functional layer can be easily formed on a support, and various functions can be exhibited while taking advantage of the application method that a functional layer can be manufactured at low cost with a simple apparatus and high productivity. It is desired to develop a method for obtaining a functional layer, for example, a transparent conductive layer having a low electric resistance value.

Accordingly, an object of the present invention is to provide a functional film having a functional layer capable of expressing various functions by a coating method, for example, a transparent conductive layer having a low electric resistance value. In particular, an object of the present invention is to provide the functional film having excellent flatness.

[0013]

Means for Solving the Problems Conventionally, in a coating method,
If a large amount of binder resin is not used, the functional layer cannot be formed, or if no binder resin is used,
It was thought that a functional layer would not be obtained without sintering the functional material at a high temperature. As for the conductive layer, the conductive layer cannot be formed unless a large amount of the binder resin is used, or if the binder resin is not used, the conductive layer cannot be obtained unless the conductive material is sintered at a high temperature. Was considered.

However, as a result of intensive studies, the present inventor has found that
Surprisingly, it was found that a functional layer having mechanical strength and exhibiting various functions can be obtained by compression without using a large amount of binder resin and without firing at a high temperature. Furthermore, when the relationship between the thickness of the support and the thickness of the functional layer was examined, it was found that a functional film having excellent flatness could be obtained if both had a specific relationship, and the present invention was reached.

The present invention is a functional film having a compressed layer of functional fine particles on a support, wherein the compressed layer of functional fine particles contains no resin or has a volume of 100%. And the thickness t _{S of the} support and the thickness t _F of the compressed layer of the functional fine particles have a relationship of t _S / t _F ≧ 25. Film. In the present invention, the term functional layer is used synonymously with a compressed layer of functional fine particles. In the present invention, the compressed layer of the functional fine particles preferably does not contain a resin.

The compressed layer of functional fine particles is obtained by compressing a functional fine particle-containing layer formed by applying a liquid in which functional fine particles are dispersed on a support and drying the liquid. The dispersion liquid does not contain a resin or is represented by the volume before dispersion, and the volume of the functional fine particles is 100%.
And contains less than 25 volumes of resin. That is, the content of the resin in the layer containing the functional fine particles at the time of forming the compressed layer corresponds to the content of the resin in the dispersion of the functional fine particles.

The compressed layer of the functional fine particles has a thickness of 44 N / m.
It is preferably obtained by compressing with a compression force of m ² or more.

The effect of the present invention is great when the support is a resin film.

In the present invention, the functional layer includes, for example, a conductive layer, a magnetic layer, a ferromagnetic layer, a dielectric layer, a ferroelectric layer, an electrochromic layer, an electroluminescent layer, an insulating layer, a light absorbing layer, and a light absorbing layer. It is selected from a selective absorption layer, a reflection layer, an antireflection layer, a catalyst layer and a photocatalyst layer. It is preferable to use various functional fine particles that exhibit a desired function.

When conductive fine particles are used as the functional fine particles in the functional film, a functional film having a conductive layer can be obtained. In the functional film, the compressed layer of the functional fine particles is preferably a transparent conductive layer.

[0021]

FIG. 1 is a sectional view showing an example of the functional film of the present invention. The functional film (1) has a compressed layer (3) of functional fine particles on a support (2). The thickness t _S of the support (2) and the compressed layer (3) of the functional fine particles
The thickness t _F of, a relationship of t _S / t _F ≧ 25.

In the present invention, the functional layer is not particularly limited, and may be a conductive layer, a magnetic layer, a ferromagnetic layer, a dielectric layer, a ferroelectric layer, an electrochromic layer, an electroluminescent layer, an insulating layer, Light absorption layer, light selective absorption layer,
Films having various functions such as a reflection layer, an antireflection layer, a catalyst layer, and a photocatalyst layer are included. Therefore, in the present invention, the functional fine particles that constitute the target layer are used.
The functional fine particles are not particularly limited, and mainly inorganic fine particles having a cohesive force are used. In the production of any functional layer, by applying the method of the present invention, a functional coating film having sufficient mechanical strength can be obtained, and a binder in a conventional coating method using a large amount of a binder resin. The adverse effects of the resin can be eliminated. As a result, the intended function is further improved.

For example, in the production of a transparent conductive layer, tin oxide, indium oxide, zinc oxide, cadmium oxide, antimony-doped tin oxide (ATO), fluorine-doped tin oxide (FTO), tin-doped indium oxide (ITO), aluminum Conductive inorganic fine particles such as doped zinc oxide (AZO) are used. Alternatively, organic conductive fine particles may be used. By applying the present manufacturing method, excellent conductivity can be obtained.

Here, "transparent" means that visible light is transmitted. Regarding the degree of light scattering, the required level differs depending on the use of the conductive layer. In the present invention, those having scattering which is generally called translucent are also included.

In the production of a ferromagnetic layer, γ-Fe ₂ O
₃ , iron oxide-based magnetic powders such as Fe ₃ O ₄ , Co—FeOx, and Ba ferrite, α-Fe, Fe—Co, Fe—N
i, a ferromagnetic alloy powder containing a ferromagnetic metal element such as Fe-Co-Ni, Co, or Co-Ni as a main component is used.
By applying this manufacturing method, the saturation magnetic flux density of the magnetic coating film is improved.

In manufacturing a dielectric layer or a ferroelectric layer,
Magnesium titanate, barium titanate, strontium titanate, lead titanate, lead zirconate titanate (PZT), lead zirconate, lanthanum-added lead zirconate titanate (PLZT), magnesium silicate Fine particles of a dielectric or ferroelectric material such as a system and a lead-containing perovskite compound are used. By applying the present manufacturing method, the dielectric characteristics or the ferroelectric characteristics can be improved.

In the production of a metal oxide layer exhibiting various functions, iron oxide (Fe ₂ O ₃ ), silicon oxide (SiO ₂ )
₂ ), aluminum oxide (Al ₂ O ₃ ), titanium dioxide (TiO ₂ ), titanium oxide (TiO), zinc oxide (Zn)
Fine particles of metal oxides such as O), zirconium oxide (ZrO ₂ ), and tungsten oxide (WO ₃ ) are used. By applying this manufacturing method, the degree of filling of the metal oxide in the film is increased, and each function is improved. For example, when SiO ₂ or Al ₂ O ₃ carrying a catalyst is used, a porous catalyst layer having practical strength can be obtained. When TiO ₂ is used, the photocatalytic function can be improved. In addition, WO
_{When 3} is used, an improvement in the coloring effect in the electrochromic display element can be obtained.

In the manufacture of the electroluminescent layer, zinc sulfide (ZnS) fine particles are used.
By applying the present manufacturing method, an inexpensive electroluminescent layer can be manufactured by a coating method.

Although the particle size of the functional fine particles cannot be unconditionally determined because it depends on the application and the shape of the particles, it is generally 5 nm to 10 nm.
It is about μm. For example, the particle size of the conductive fine particles varies depending on the degree of scattering required according to the application of the conductive film, and cannot be unconditionally determined depending on the shape of the particles, but is generally 10 μm or less, and is 1.0 μm or less. Is preferred,
5 nm-100 nm is more preferable.

The thickness t _F of the functional fine particle layer formed by compression depends on the intended use.
It is about 10 μm to 10 μm.

In the present invention, a liquid in which functional fine particles selected from the above-mentioned various functional fine particles are dispersed according to the purpose is used as a functional paint. This functional paint is applied on a support and dried to form a layer containing functional fine particles. Thereafter, the layer containing the functional fine particles is compressed to form a compressed layer of the functional fine particles to obtain a functional layer.

The liquid in which functional fine particles such as conductive fine particles are dispersed is not particularly limited, and various known liquids can be used. For example, as a liquid, saturated hydrocarbons such as hexane, aromatic hydrocarbons such as toluene and xylene, alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and diisobutyl ketone , Ethyl acetate, esters such as butyl acetate, ethers such as tetrahydrofuran, dioxane, diethyl ether, N, N-dimethylformamide;
Examples include amides such as N-methylpyrrolidone (NMP) and N, N-dimethylacetamide, and halogenated hydrocarbons such as ethylene chloride and chlorobenzene. Among these, a liquid having polarity is preferable,
Especially alcohols such as methanol and ethanol, NMP
Those having an affinity for water, such as amides, have good dispersibility even without using a dispersant, and are suitable. These liquids can be used alone or in combination of two or more. Further, a dispersant can be used depending on the type of the liquid.

In addition, water can be used as the liquid.
When water is used, the support needs to be hydrophilic. Since the resin film is usually hydrophobic, it easily repels water, and it is difficult to obtain a uniform film. When the support is a resin film, it is necessary to mix alcohol with water or to make the surface of the support hydrophilic.

The amount of the liquid to be used is not particularly limited as long as the dispersion of the fine particles has a viscosity suitable for coating. For example, the liquid is about 100 to 100,000 parts by weight based on 100 parts by weight of the fine particles. It may be appropriately selected according to the types of the fine particles and the liquid.

The fine particles may be dispersed in the liquid by a known dispersion technique. For example, the particles are dispersed by a sand grinder mill method. At the time of dispersion, it is also preferable to use a medium such as zirconia beads in order to loosen the aggregation of the fine particles. At the time of dispersion, care should be taken not to mix impurities such as dust.

In the present invention, the dispersion liquid of the fine particles is
When no resin is contained (that is, the amount of resin is 0), or when a resin is contained, the content of the resin is represented by the volume before dispersion and is less than 25 when the volume of the functional fine particles is 100. Volume. By using such a dispersion, the resin amount of the obtained functional fine particles in the compressed layer is 0 or a volume of less than 25 when the volume of the functional fine particles is 100.

In the conductive layer, if no resin is used,
The resin does not hinder contact between the conductive fine particles. Accordingly, conductivity between the conductive fine particles is ensured, and the electrical resistance of the obtained conductive layer is low. It is possible to include a resin as long as the conductivity is not impaired, but the amount is small as compared with the amount used as a binder resin in the prior art as the upper limit described above. In the prior art, strong compression was not performed, so that a large amount of binder had to be used to obtain the mechanical strength of the coating film. If the resin is used in such an amount that it plays a role as a binder, contact between the conductive fine particles is hindered by the binder, electron transfer between the fine particles is hindered, and the conductivity is reduced.

On the other hand, the resin has the effect of improving the haze of the conductive layer. However, in terms of conductivity,
The resin is used in a volume range of less than 25, and more preferably in a volume range of less than 20, when the volume of the conductive fine particles is expressed as 100 before dispersion. Although the effect of improving the haze is reduced, the resin may be used in a volume of less than 3.7 from the viewpoint of conductivity.

Even in a functional layer using WO ₃ fine particles or TiO ₂ fine particles, if no resin is used, the resin does not hinder contact between the fine particles.
Each function is improved. As long as the contact between the fine particles is not hindered and the respective functions are not impaired, it is possible to contain a resin.
When it is set to 0, the volume is, for example, about 80 or less.

In the catalyst layer using Al ₂ O ₃ fine particles, if no resin is used, the surface of the fine particles having a catalytic function will not be covered with the resin. For this reason,
The function as a catalyst is improved. In the catalyst layer, the more voids inside the membrane, the more active sites as a catalyst, so from this viewpoint it is preferable to use no resin.

As described above, it is preferable not to use a resin in the functional layer at the time of compression (that is, in the dispersion of the fine particles), and it is preferable to use a small amount of the resin even if it is used. The amount of the resin when used, depending on the purpose of the functional layer,
Since it may vary to some extent, it may be determined appropriately.

In the present invention, the volume of the functional fine particles and the volume of the resin are not apparent volumes but true volumes. The true volume is obtained by obtaining the density using an instrument such as a pycnometer based on JIS Z 8807, and dividing the weight of the material used by the density. In this way, the amount of resin used is defined not by weight but by volume,
This is because when considering how the resin is present with respect to the functional fine particles in the functional film obtained after compression, the reality is more reflected.

When a resin is used in the present invention, the resin is not particularly limited, and a thermoplastic resin or a polymer having rubber elasticity can be used alone or as a mixture of two or more. Examples of the resin, fluorine-based polymer, silicone resin, acrylic resin, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose diacetyl cellulose,
Examples thereof include polyvinyl chloride, polyvinylpyrrolidone, polyethylene, polypropylene, SBR, polybutadiene, and polyethylene oxide. Examples of the fluorine-based polymer include polytetrafluoroethylene, polyvinylidene fluoride (PVDF), vinylidene fluoride-ethylene trifluoride copolymer, ethylene-tetrafluoroethylene copolymer, propylene-tetrafluoroethylene copolymer, and the like. Can be Further, a fluorine-containing polymer in which hydrogen in the main chain is substituted with an alkyl group can also be used. The higher the density of the resin, the smaller the volume, even if a large weight is used, and it is easy to satisfy the requirements of the present invention.

Various additives may be added to the dispersion of the fine particles within a range satisfying the performance required for each function such as conductivity and catalytic action. For example, ultraviolet absorbers,
It is an additive such as a surfactant and a dispersant.

As the support, a film or a sheet can be used, and in the present invention, a resin film or a resin sheet is preferable. The resin film is preferable in that it does not crack even if the compression force in the compression step is increased, and that the compressed layer of functional fine particles such as conductive fine particles has good adhesion to the film, and is also required to be lightweight. It is also suitable for. In the present invention, a resin film can be used as a support because there is no pressurizing step at a high temperature or a firing step.

Examples of the resin film include a polyester film such as polyethylene terephthalate (PET), a polyolefin film such as polyethylene or polypropylene, a polycarbonate film, an acrylic film, a norbornene film (arton, manufactured by JSR Corporation) and the like. .

In the present invention, the thickness t _S of the support is determined by the thickness t _F of the compressed layer of the functional fine particles and t _S / t _F ≧ 2.
5 is selected. That is, the thickness t _S of the support is set to be at least 25 times the desired thickness t _F of the compression layer. For example, the desired thickness t _F of the compression layer is 1 μm.
If m, the thickness t _S of the support is set to 25 μm or more.
Although the upper limit of the thickness t _S of the support cannot be unconditionally determined depending on the application, it is about 100 mm.
mm.

By using a support having a thickness t _S that satisfies the above relationship, even if a compression operation is performed under a strong pressure to form a compressed layer of the functional fine particles, the resulting functional film may have a flat surface. Nature is secured. This will be described with reference to FIG.

FIG. 2 is a diagram for explaining the formation of a compressed layer of functional fine particles. In (a), a functional fine particle-containing layer (3A) is formed on a support (2) by applying and drying a dispersion of the fine particles. FIG. 2A schematically shows the functional fine particles (P) before compression.

The functional fine particle-containing layer (3A) is compressed in the layer thickness direction, that is, a force in the layer thickness direction is applied to the fine particles (P) to form a compressed layer (3) of functional fine particles. At this time, when viewed microscopically, the fine particles tend to spread in a direction perpendicular to the compression direction (that is, in the direction of the support film surface). on the other hand,
The spread of the support film in the plane direction during compression is much smaller than the degree of spread of the fine particles. Therefore, the functional film obtained by compression tends to be curved with the fine particle compression layer side being convex. When the curvature becomes severe, the functional film becomes cylindrical.

[0051] If thicker support, can reduce the degree of curvature, the result of the experiment, the thickness t _S of the support,
If 25 times the desired thickness t _F of the compression layer, the flatness of the resulting functional film has revealed that is secured [(b) see Figure]. The thickness of the support is t _S / t
_{When F} <25, it is difficult to ensure the flatness of the obtained functional film (see FIG. 3C), and the functional film may be formed into a tubular shape.

The dispersion of the fine particles is coated on the support and dried to form a layer containing functional fine particles such as a layer containing conductive fine particles. The application of the fine particle dispersion on the support can be performed by a known method without any particular limitation. For example, it can be performed by a coating method such as a reverse roll method, a direct roll method, a blade method, a knife method, an extrusion nozzle method, a curtain method, a gravure roll method, a bar coat method, a dip method, a kiss coat method, and a squeeze method. Further, the dispersion liquid can be attached to the support by spraying or spraying.

The drying temperature depends on the type of liquid used for dispersion, but is preferably about 10 to 150 ° C. If the temperature is lower than 10 ° C., dew condensation of moisture in the air tends to occur, and if the temperature exceeds 150 ° C., the resin film support is deformed. At the time of drying, care is taken so that impurities do not adhere to the surface of the fine particles.

The thickness of the functional fine particle-containing layer such as the conductive fine particle-containing layer after coating and drying depends on the compression conditions in the next step and the use of each functional film such as the final conductive film. 1
It may be about 0 μm.

As described above, when the functional fine particles such as the conductive fine particles are dispersed in a liquid, applied and dried, a uniform film can be easily formed. When the dispersion of the fine particles is applied and dried, the fine particles form a film even when the binder is not present in the dispersion. Although the reason for forming a film without the presence of a binder is not always clear, fine particles gather together due to capillary force when the liquid is dried and the amount of liquid decreases. Furthermore, the fact that the particles are fine particles has a large specific surface area and a strong cohesive force, so it is thought that they may become a film. However, the strength of the film at this stage is weak. In the conductive layer, the resistance value is high, and the variation in the resistance value is large.

Next, the formed layer containing functional fine particles such as the layer containing conductive fine particles is compressed to obtain a compressed layer of functional fine particles such as conductive fine particles. The compression improves the strength of the film. That is, by compressing, the number of contact points between functional fine particles such as conductive fine particles increases, and the contact surface increases. For this reason, the strength of the coating film increases. Since the fine particles originally have a property of easily aggregating, they become a strong film by being compressed.

In the conductive layer, the strength of the coating film increases and the electrical resistance decreases. The catalyst layer becomes a porous layer because the strength of the coating film increases and no resin is used or the amount of the resin is small. Therefore, a higher catalytic function can be obtained. In other functional layers as well, a high-strength film in which the fine particles are connected to each other can be obtained, and the amount of the fine particles per unit volume increases because no resin is used or the amount of the resin is small. Therefore, higher functions can be obtained.

The compression is preferably performed with a compression force of 44 N / mm ² or more. If the pressure is lower than 44 N / mm ² ,
A layer containing functional fine particles such as a layer containing conductive fine particles cannot be sufficiently compressed, and for example, it is difficult to obtain a conductive layer having excellent conductivity. 135N / mm ² or more compressive force and more preferably, compressive force of 180 N / mm ² is more preferable. The higher the compressive force, the higher the strength of the coating film and the better the adhesion to the support. In the conductive layer, a film having more excellent conductivity is obtained, the strength of the conductive layer is improved, and the adhesion between the conductive layer and the support becomes strong. Generally, the higher the compression force, the higher the pressure resistance of the device.
Compression forces up to N / mm ² are suitable. Further, it is preferable that the compression is performed at a temperature near normal temperature (15 to 40 ° C.).
The compression operation at a temperature near normal temperature is one of the advantages of the present invention.

The compression can be performed without any particular limitation by a sheet press, a roll press or the like, but is preferably performed using a roll press machine. The roll press is a method of sandwiching a film to be compressed between rolls, compressing the roll, and rotating the roll. The roll press is preferably applied with a high pressure uniformly, and can be produced in a roll-to-roll manner, so that productivity is increased.

The roll temperature of the roll press is preferably room temperature. In a heated atmosphere or in a compression (hot press) in which a roll is heated, when the compression pressure is increased, a problem such as the resin film being elongated occurs. If the compression pressure is reduced to prevent the resin film of the support from stretching under heating, the mechanical strength of the coating film decreases. In the conductive layer, the mechanical strength of the coating film decreases, and the electric resistance increases.
If there is a reason to reduce the adhesion of moisture on the surface of the fine particles as much as possible, a heated atmosphere may be used to reduce the relative humidity of the atmosphere, but the temperature range is within the range where the film does not easily stretch. It is. Generally, the temperature is lower than the glass transition temperature (secondary transition temperature). The temperature may be set slightly higher than the temperature at which the required humidity is obtained in consideration of fluctuations in humidity. It is also preferable to adjust the temperature so that the roll temperature does not rise due to heat generation when continuously compressed by a roll press.

The glass transition temperature of the resin film is as follows:
It is determined by measuring dynamic viscoelasticity and refers to the temperature at which the mechanical loss of the main dispersion peaks. For example, looking at a PET film, its glass transition temperature is around 110 ° C.

The roll of the roll press machine is preferably a metal roll because a strong pressure is applied. In addition, if the roll surface is soft, fine particles may be transferred to the roll during compression. Therefore, it is preferable to treat the roll surface with a hard film.

Thus, a compressed layer of functional fine particles such as conductive fine particles is formed. The thickness of the compressed layer of functional fine particles such as conductive fine particles depends on the application, but is preferably 0.1 to
It may be about 10 μm. Further, in order to obtain a compressed layer having a thickness of about 10 μm, a series of operations of coating, drying, and compressing a dispersion liquid of fine particles may be repeatedly performed.

Each functional layer such as the obtained transparent conductive layer is
Demonstrates excellent functionalities such as excellent conductivity and catalysis, and has sufficient film strength for practical use despite the fact that it is made with a small amount of resin that does not use a binder resin or does not function as a binder. And excellent adhesion to the support.

[0065]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to these examples. Examples 1 to 11 and Comparative Examples 1 to 4 are examples in which ITO fine particles were used as conductive fine particles in order to obtain a transparent conductive film for an electroluminescent panel electrode.

Example 1 I having a primary particle size of 5 to 30 nm
TO fine particles SUFP-HX (Sumitomo Metal Mining Co., Ltd.) 1
400 parts by weight of ethanol was added to 00 parts by weight, and the medium was dispersed as zirconia beads using a disperser. In the following Examples 2 to 10 and Comparative Examples 1 to 4, the same coating liquid was used. The obtained coating solution was applied on a PET film having a thickness of 25 μm using a bar coater, and dried by sending warm air at 50 ° C. The resulting film is hereinafter referred to as a pre-compression ITO film. The thickness of the ITO-containing coating film was 0.9 μm.

First, a preliminary experiment for confirming the compression pressure was performed. Room temperature (23 ° C.) using a roll press equipped with a pair of 140 mm-diameter metal rolls (having a roll surface subjected to hard chrome plating) without rotating the rolls and without heating the rolls The above-mentioned ITO film before compression was sandwiched and compressed. At this time, the pressure per unit length in the film width direction was 660 N / mm. Next, the pressure was released, and the length of the compressed portion in the longitudinal direction of the film was 1.9 mm. From this result, it can be said that compression was performed at a pressure of 347 N / mm ² per unit area.

Next, the same pre-compressed ITO film as that used in the preliminary experiment was sandwiched between metal rolls and compressed under the above conditions, and the rolls were rotated and compressed at a feed speed of 5 m / min. Thus, a compressed ITO film was obtained. The thickness of the ITO compression layer was 0.5 μm.

(Bending Test) The obtained long conductive film was cut into a rectangle having a width of 50 mm and a length of 200 mm to obtain a test sample. While holding both ends (50 mm side) of the test sample by hand and spreading them, the test sample was placed on a horizontal flat table such that the functional layer side was on the top, and then released. Next, it was observed whether the test sample remained spread on the horizontal flat table, or whether the test sample was curved with the functional layer on the outside and rounded into a cylindrical shape. The test sample that had been spread on the flat table was regarded as a good product, and the test sample that was curved and rounded into a cylindrical shape was regarded as a defective product. The sample of Example 1 did not curl and remained spread on the horizontal flat table (good product).

(Electrical resistance)
It was cut into a size of 0 mm x 50 mm. A tester was applied to two corners at diagonal positions to measure electric resistance. In the sample of Example 1, it was 2 kΩ.

[Embodiment 2] In the embodiment 1, the pre-compression I
The thickness of the ITO-containing coating film on the TO film is 1.7 μm.
m. This uncompressed ITO film was compressed in the same manner as in Example 1 to obtain a conductive film having a thickness of 1.0 μm of the ITO compressed layer. When the bending test was performed, the sample of Example 2 was a good product. The electric resistance was 1 kΩ.

[Comparative Example 1] In Example 1, the pre-compression I
The thickness of the ITO-containing coating film in the TO film is 3.4 μm.
m. This uncompressed ITO film was compressed in the same manner as in Example 1 to obtain a 2.0 μm-thick conductive film of an ITO compressed layer. When the bending test was performed, the sample of Comparative Example 1 was rounded into a cylindrical shape with the ITO compressed layer on the outside (defective product). The electric resistance was 0.5 kΩ.

Example 3 P having a thickness of 50 μm was used as a support.
Using an ET film, a pre-compression ITO film was obtained in the same manner as in Example 1, except that the thickness of the ITO-containing coating film in the pre-compression ITO film was changed to 1.7 μm. This uncompressed ITO film was compressed in the same manner as in Example 1, and
A conductive film having a TO compression layer thickness of 1.0 μm was obtained.
When the bending test was performed, the sample of Example 3 was good. The electric resistance was 1 kΩ.

[Embodiment 4] In Embodiment 3, the pre-compression I
The thickness of the ITO-containing coating film in the TO film is 3.4 μm.
m. This uncompressed ITO film was compressed in the same manner as in Example 1 to obtain a 2.0 μm-thick conductive film of an ITO compressed layer. When the bending test was performed, the sample of Example 4 was good. The electric resistance was 0.5 kΩ.

[Embodiment 5] In Embodiment 4, the pre-compression I
Except that the compression of the TO film was performed at a pressure of 500 N / mm ² , the thickness of the ITO compression layer was set to 2.
A conductive film of 0 μm was obtained. When the bending test was performed, the sample of Example 5 was good. The electrical resistance is
It was 0.4 kΩ.

[Embodiment 6] In Embodiment 4, the pre-compression I
Except that the compression of the TO film was performed at a pressure of 183 N / mm ² , the thickness of the ITO compression layer was set in the same manner as in Example 4.
A conductive film of 0 μm was obtained. When the bending test was performed, the sample of Example 6 was a good product. The electrical resistance is
It was 0.7 kΩ.

[Comparative Example 2] In Example 3, the pre-compression I
The thickness of the ITO-containing coating film in the TO film is 5.0 μm.
m. This pre-compression ITO film was compressed in the same manner as in Example 1 to obtain a conductive film having a thickness of the ITO compression layer of 3.0 μm. When the bending test was performed, the sample of Comparative Example 2 was defective. The electric resistance was 0.3 kΩ.

Example 7 The same operation as in Example 1 was conducted except that a 100 μm thick PET film was used as the support, and the thickness of the ITO-containing coating film in the pre-compression ITO film was changed to 1.7 μm. An ITO film was obtained. This uncompressed ITO film is compressed in the same manner as in Example 1,
A conductive film having a thickness of 1.0 μm of the ITO compression layer was obtained. When the bending test was performed, the sample of Example 7 was good. The electric resistance was 1 kΩ.

[Embodiment 8] In Embodiment 7, the pre-compression I
The thickness of the ITO-containing coating film in the TO film is 6.6 μm.
m. This ITO film before compression was compressed in the same manner as in Example 1 to obtain a conductive film having a thickness of 4.0 μm of the ITO compressed layer. When the bending test was performed, the sample of Example 8 was good. The electric resistance was 0.3 kΩ.

[Comparative Example 3] In Example 7, the pre-compression I
When the thickness of the ITO-containing coating film in the TO film is 10.0
μm. This ITO film before compression was compressed in the same manner as in Example 1 to obtain a conductive film having a thickness of 6.0 μm of the ITO compressed layer. When the bending test was performed, the sample of Comparative Example 3 was defective. The electric resistance was 0.2 kΩ.

Example 9 Using a 100 μm thick ARTON film (manufactured by JSR Corporation) as a support, the thickness of the ITO-containing coating film in the ITO film before compression was set to 3.4.
The pre-compression IT
An O film was obtained. This uncompressed ITO film was compressed in the same manner as in Example 1 to obtain a 2.0 μm-thick conductive film of an ITO compressed layer. When the bending test was performed, the sample of Example 9 was good. Electric resistance is 0.5k
Ω.

[Example 10] In Example 9, the thickness of the ITO-containing coating film in the ITO film before compression was 6.6.
μm. This ITO film before compression was compressed in the same manner as in Example 1 to obtain a conductive film having a thickness of 4.0 μm of the ITO compressed layer. When a bending test was performed, Example 10 was performed.
Was a good sample. The electric resistance was 0.3 kΩ.

[Comparative Example 4] In Example 9, the pre-compression I
When the thickness of the ITO-containing coating film in the TO film is 10.0
μm. This ITO film before compression was compressed in the same manner as in Example 1 to obtain a conductive film having a thickness of 6.0 μm of the ITO compressed layer. When the bending test was performed, the sample of Comparative Example 4 was defective. The electric resistance was 0.2 kΩ.

[Example 11] ITO fine particles SUFP-HX having a primary particle size of 5 to 30 nm (manufactured by Sumitomo Metal Mining Co., Ltd.)
1900 parts by weight of ethanol was added to 100 parts by weight, and the medium was dispersed as zirconia beads using a disperser. A 300 μm thick PET film was used as a support, and the thickness of the ITO-containing coating film in the ITO film before compression was set to 0.2 μm. This ITO film before compression was compressed in the same manner as in Example 1 to obtain a conductive film having a thickness of 0.1 μm of the ITO compressed layer. When the bending test was performed, the sample of Example 11 was good. Electric resistance is 18k
Ω.

[0085]

[Table 1]

Table 1 shows the results of Examples 1 to 11 and Comparative Examples 1 to 4. Each of the conductive films of Examples 1 to 11 was excellent in low electric resistance value and without curving. In addition, they were excellent in adhesion between the conductive layer and the support film, and also excellent in transparency. On the other hand, in the case of Comparative Examples 1 to 4, since the thickness of the support was relatively small with respect to the conductive fine particle compression layer, the support was curved, and there was a difficulty in handling from a practical viewpoint.

The following examples are examples in which titanium oxide (TiO ₂ ) fine particles were used as inorganic fine particles to form an inorganic material film for a photocatalytic film.

Example 12 Primary Particle Size is 30 to 70 nm
Was added to 100 parts by weight of TiO ₂ fine particles, and the medium was dispersed as zirconia beads using a disperser. The obtained coating solution was applied on a PET film having a thickness of 25 μm using a bar coater, and dried by sending warm air at 50 ° C. The obtained film is subjected to TiO before compression.
Called _two films. The thickness of the TiO ₂ -containing coating is 0.8
μm. This TiO ₂ film before compression was used in Example 1.
Compressed at a pressure of 347 N / mm ² in the same manner as described above to obtain a compressed TiO ₂ film. The thickness of the TiO ₂ compression layer is 0.
It was 5 μm. When a bending test was performed, Example 12 was performed.
Was a good sample.

[0089] In Example 13 Example 12, the thickness of the TiO ₂ -containing coating film in the compression before TiO ₂ film was 1.5 [mu] m. This uncompressed TiO ₂ film was compressed in the same manner as in Example 1 to obtain a TiO ₂ compressed layer having a thickness of 1.0 μm.
m was obtained. When the bending test was performed, the sample of Example 13 was a good product.

[0090] In Comparative Example 5 Example 12, the thickness of the TiO ₂ -containing coating film in the compression before TiO ₂ film was 3.0 [mu] m. This uncompressed TiO ₂ film was compressed in the same manner as in Example 1 to obtain a TiO ₂ compressed layer having a thickness of 2.0 μm.
m was obtained. When the bending test was performed, the sample of Comparative Example 5 was defective.

[0091]

[Table 2]

Table 2 shows the results of Examples 12 and 13 and Comparative Example 5. Each of the films of Examples 12 and 13 was excellent without causing any curvature. On the other hand, in the case of Comparative Example 5, since the thickness of the support was relatively small as compared with the compressed layer of titanium oxide fine particles, there was a difficulty in handling from the practical point of view.

In the above example, the inorganic fine particles were made of IT
An example was shown in which an inorganic functional film was produced using O fine particles and TiO ₂ fine particles, respectively. Various inorganic functional films can be produced using inorganic fine particles having various properties in the same manner as in the above examples. Therefore, the above-described embodiments are merely illustrative in every respect,
It should not be interpreted restrictively. Furthermore, all modifications belonging to the equivalent scope of the claims are within the scope of the present invention.

[0094]

According to the present invention, a functional film can be obtained by a simple operation of applying a coating material containing functional fine particles to a support and then compressing the coating. The functional film according to the present invention has sufficient mechanical strength and eliminates the adverse effects of the binder resin in the conventional coating method, and as a result, the intended function is further improved. Moreover, according to the present invention, since the thickness of the support and the thickness of the compressed layer of the functional fine particles have a specific relationship, the flatness of the functional film is ensured, and the handleability is excellent from a practical viewpoint. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of the functional film of the present invention.

FIG. 2 is a diagram for explaining formation of a compressed layer of functional fine particles.

[Explanation of symbols]

(1): Functional film (2): Support (3): Compressed layer of functional fine particles (3A): Layer containing functional fine particles before compression (P): Functional fine particles before compression t _S : Support Thickness of (2) t _F : Thickness of compressed layer of functional fine particles (3)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 13/00 503 H01B 13/00 503Z F term (Reference) 4D075 BB05Z CA22 DA04 DB31 DC22 EA02 EC02 4F100 AB33 AK01A AK01B AK42 AT00A BA02 DE01B EH46B EJ19B EJ86B GB41 JG01B JK01 JK15 JL05 YY00B 5G307 FA02 FB01 FC10 5G323 AA01

Claims (5)

[Claims] 1. A functional film having a compressed layer of functional fine particles on a support, wherein the compressed layer of functional fine particles contains no resin or has a volume of 100 of the functional fine particles. A functional film containing a resin having a volume of less than 25, and wherein the thickness t _{S of the} support and the thickness t _F of the compressed layer of the functional fine particles are in a relationship of t _S / t _F ≧ 25. 2. The compressed layer of functional fine particles is obtained by compressing a functional fine particle-containing layer formed by applying a liquid in which functional fine particles are dispersed on a support and drying the liquid. The dispersion liquid contains no resin or is represented by the volume before dispersion, and the volume of the functional fine particles is 10%.
The functional film according to claim 1, wherein the functional film contains a resin having a volume of less than 25 when 0. 3. The compressed layer of the functional fine particles has a thickness of 44 N /
The functional film according to claim 1, which is obtained by compressing with a compressive force of not less than ² mm ² . 4. The functional film according to claim 1, wherein the support is a resin film. 5. The functional film according to claim 1, wherein the functional fine particles are conductive fine particles.