JP5960989B2 - Titanium oxide-containing porous membrane laminate and method for producing the same - Google Patents

Description

  The present invention relates to a titanium oxide-containing porous membrane laminate and a method for producing the same, and more particularly to a laminate of a titanium oxide-containing porous membrane and a film with an ITO transparent conductive film and a method for producing the same. This laminate can be used, for example, as a base material for electronic products such as electronic paper materials and electrodes of dye-sensitized solar cells.

  In recent years, in the United States and other countries, electronic books are entering a full-fledged period due to attractive electronic book terminals and abundant contents. Electronic paper and liquid crystal panels are used for this electronic book. Electronic paper is easy to read like paper, is thin and lightweight, features ultra-low power consumption, and can rewrite characters and image display. Since the whitened part of the electronic paper reflects sunlight and indoor illumination light, and the text and images are displayed in the blackened part, it is gentle to the human eye like printed matter, and for a long time. I'm never tired of reading the letters. On the other hand, liquid crystal screens of mobile phones and the like always emit light, and it is said that eyes are tired when used for a long time. Thus, in electronic paper, visibility equal to that of paper is one of the research and development goals where the highest priority is given. For this purpose, it is very important to increase the reflectance. Of the various electronic paper systems, the most popular microcapsule electrophoresis system has a reflectivity of about 35%, which is lower than 50-60% of newspaper, and is not always sufficient at present. It can be said that increasing the reflectance leads to an increase in visibility and is preferable.

  On the other hand, in the hope of expanding the use of renewable energy, there is an expectation for solar cells that use inexhaustible sunlight, and the market continues to expand. However, crystalline silicon solar cells, which account for more than 90% of the current global market, are concerned about the stable supply of high-purity silicon raw materials. In these circumstances, attention has been focused on dye-sensitized solar cells. Cost reduction can be expected and the market is expected to expand into new fields due to its colorfulness. In dye-sensitized solar cells, a porous titanium oxide film is often used as a photoelectrode. The titanium oxide porous film is formed by applying a titanium oxide paste on a transparent electrode and drying the solvent, but there are problems in adhesion and cracking. JP 2010-267557 A and JP 2011-034835 A propose a laminate in which a porous film made of only titanium oxide is laminated on a film with an ITO transparent conductive film. However, a porous film made of only titanium oxide is fragile and inferior in flexibility, and thus has a problem that it is difficult to handle during production.

JP 2010-267557 A JP 2011-034835 A

An object of the present invention is to provide a titanium oxide-containing porous film laminate in which a porous film containing titanium oxide is laminated on a film with an ITO transparent conductive film and is excellent in flexibility.
Another object of the present invention is to provide an industrially efficient method for producing the titanium oxide-containing porous membrane laminate.

  In order to achieve the above object, the inventors of the present invention have made extensive studies and as a result, the ITO transparent conductive film of the ITO transparent conductive film includes a polymer and a titanium oxide particle that should form a porous film. When the porous membrane-forming material dispersion is cast into a film and then immersed in a coagulation solution and then dried, unexpectedly, a porous membrane can be formed even if the titanium oxide content is high. Along with this, the porous film is laminated on the ITO transparent conductive film with good adhesion, and as a result, a flexible and flexible laminate of the titanium oxide-containing porous film and the ITO transparent conductive film is obtained, The present invention has been completed.

  That is, the present invention is an oxidation characterized in that a porous film formed of a composition containing a polymer and titanium oxide particles is laminated on the ITO transparent conductive film of the ITO transparent conductive film-attached film. A titanium-containing porous membrane laminate is provided.

  In the porous film, the average pore diameter may be 0.01 to 10 μm, and the porosity may be 30 to 85%.

  The polymer is at least one selected from the group consisting of polyimide resins, polyamideimide resins, polyetherimide resins, polyethersulfone resins, cellulose resins, polyamide resins, and polysulfone resins. preferable.

  The average particle diameter of the primary particles of the titanium oxide particles is, for example, 0.01 to 10 μm.

  The content of titanium oxide particles in the porous membrane is, for example, 10 to 95% by weight.

  The thickness of the porous film is, for example, 5 to 200 μm.

  The film substrate in the film with ITO transparent conductive film preferably contains a polyethylene terephthalate film.

  The porous film is formed by applying a porous film-forming material dispersion containing the polymer and the titanium oxide particles that constitute the porous film onto the ITO transparent conductive film of the ITO transparent conductive film. It may be formed by casting in the shape of a solid, and then immersing it in a coagulating liquid, followed by drying.

  The present invention is a method for producing the above-mentioned titanium oxide-containing porous membrane laminate, wherein a porous membrane-forming material dispersion containing a polymer to constitute the porous membrane and titanium oxide particles is made transparent with ITO. A method for producing a titanium oxide-containing porous film laminate comprising at least a step of casting a film with a conductive film onto the ITO transparent conductive film, then immersing it in a coagulating liquid, and then subjecting it to drying provide.

  In the said manufacturing method, after casting the said dispersion material for porous film formation on this ITO transparent conductive film of a film with an ITO transparent conductive film, relative humidity 70-100%, temperature 15-100 degreeC May be kept for 0.2 minutes or more in the atmosphere of, and then immersed in the coagulation liquid.

  The titanium oxide-containing porous membrane laminate of the present invention is excellent in flexibility because a porous membrane formed from a composition containing a polymer and titanium oxide particles is laminated on a film with an ITO transparent conductive film. . Moreover, it is excellent also in the adhesiveness of the said porous film and a film with ITO transparent conductive film formation. For this reason, problems such as cracks are less likely to occur during manufacture and use. Furthermore, since the titanium oxide-containing porous film laminate of the present invention has a titanium oxide-containing porous film, the electrode using ITO has reflection characteristics, aesthetics, adsorption characteristics (separation characteristics), wettability, photocatalytic activity, Functions such as high dielectric properties can be imparted. For this reason, for example, it can utilize as a base material material of electronic products, such as a material for electronic paper, and an electrode of a dye-sensitized solar cell.

  More specifically, the titanium oxide-containing porous membrane laminate of the present invention can be used as a material for electronic paper display devices. Since the porous film contains titanium oxide that functions as a white pigment, the reflectance can be increased. Even in the air particle movement method that does not use a liquid, it is possible to utilize the high reflectance, but the function can be exhibited more in the method in which the porous film is impregnated with the liquid. Porous membranes that do not contain titanium oxide are in a state where irregular reflection occurs at the interface between the resin and air and the reflectance is high, but when the porous membrane is impregnated with liquid, irregular reflection is suppressed and the reflectance tends to decrease. is there. However, in the porous film containing titanium oxide, even if the porous film is impregnated with a liquid, the titanium oxide has a high reflectance, so that a decrease in reflectance is reduced.

  Moreover, the titanium oxide containing porous film laminated body of this invention can be used as photoelectrodes, such as a dye-sensitized solar cell. It is possible to contain a large amount of titanium oxide in the porous film, and it can be handled as a flexible film and has excellent adhesion. Therefore, a conventional porous film made only of titanium oxide is used. Compared to the conventional photoelectrode, there is an advantage that it is hard to break. Also in a manufacturing process of a solar cell or the like, since a titanium oxide-containing porous film can be directly laminated on the ITO transparent conductive film, a dye-sensitized solar cell can be manufactured by a simplified process.

4 is an electron micrograph (SEM photograph) of the surface of the porous membrane of the titanium oxide-containing porous membrane laminate obtained in Example 3. FIG. It is an electron micrograph (SEM photograph) of the surface of the porous membrane of the titanium oxide-containing porous membrane laminate obtained in Example 6.

  In the titanium oxide-containing porous film laminate of the present invention, a porous film formed from a composition containing a polymer and titanium oxide particles is laminated on the ITO transparent conductive film of a film with an ITO transparent conductive film. Yes.

[Film with ITO transparent conductive film]
The film with an ITO transparent conductive film is not particularly limited as long as an ITO (indium tin oxide) film is formed on the surface of the film substrate.

  As said film base material, the film base material which has a resin film at least can be used, A single layer may be sufficient and the composite film which consists of several layers which consist of the same or different raw material may be sufficient. Moreover, the said film base material may be comprised only by the resin film, and the laminated body of thin-leaf bodies other than a resin film and a resin film may be sufficient as it. Examples of the thin leaf other than the resin film include a metal foil. The ITO film can be formed on the resin film, for example, by sputtering.

  Examples of the material constituting the resin film include polyimide resins, polyamideimide resins, polyethersulfone resins, polyetherimide resins, polycarbonate resins, polyphenylene sulfide resins, polyester resins (polyethylene terephthalate resins). , Polyethylene naphthalate resins, polybutylene naphthalate resins, liquid crystalline polyester resins, etc.), polyamide resins (aromatic polyamide resins, non-aromatic polyamide resins), polybenzoxazole resins, polybenzimidazole resins Resin, polybenzothiazole resin, polysulfone resin, cellulose resin, acrylic resin, polyetheretherketone resin, fluorine resin, olefin resin (including cyclic olefin resin), polyary Plastics such as over preparative resins. These materials may be used alone or in admixture of two or more, and the above copolymer of resins may be used alone or in combination of two or more. Furthermore, a polymer containing the above resin skeleton (polymer chain) in the main chain or side chain (for example, a polysiloxane-containing polyimide containing a polysiloxane and polyimide skeleton in the main chain) can also be used.

  The film substrate preferably contains at least a polyester film (particularly a polyethylene terephthalate film, a polyethylene naphthalate film, etc.). In this case, the ITO film is preferably formed on the polyester film. Moreover, the said film base material may be comprised only from the polyester film (especially polyethylene terephthalate film), and may be a laminated body of a polyester film, and other thin films other than a resin film and / or a resin film. Good.

  The thickness of the film with ITO transparent conductive film (or film substrate) is, for example, 1 to 300 μm, preferably 50 to 250 μm, and more preferably 100 to 200 μm. If the thickness is too thin, handling becomes difficult, while if it is too thick, the flexibility may decrease.

[Porous membrane]
The porous film in the present invention is a porous film formed from a composition containing a polymer and titanium oxide, and has a large number of micropores. The average pore diameter of pores (micropores) in the porous membrane is preferably in the range of 0.01 to 10 μm, and the porosity is preferably in the range of 30 to 85%. In this porous film, the titanium oxide particles are dispersed with good uniformity in the polymer. Further, since the titanium oxide particles are dispersed in the polymer, a high porosity is maintained without filling the pores.

  Examples of the polymer constituting the porous membrane include polyimide resins, polyamideimide resins, polyetherimide resins, polyethersulfone resins, cellulose resins, polyamide resins (aromatic polyamide resins, non-aromatics). Group polyamide resins), polysulfone resins, acrylic resins, aramid resins, polyimidazole resins, polyparaphenylene benzoxazole resins, polyphenylene sulfide resins, polyarylate resins, polyester resins (liquid crystalline polyester resins) Include), polycarbonate resins, polyether ether ketone resins, and the like. These resins may be copolymers (graft copolymers, block copolymers, random copolymers). In addition, a polymer containing the resin skeleton (polymer chain) in the main chain or side chain (for example, a polysiloxane-containing polyimide containing a polysiloxane and polyimide skeleton in the main chain) can also be used. These resins can be used alone or in combination of two or more.

  Among these, as the polymer, polyimide resin, polyamideimide resin, polyetherimide resin, polyethersulfone resin, cellulose resin, polyamide resin (aromatic polyamide resin, non-aromatic polyamide resin) And at least one selected from the group consisting of polysulfone resins. In particular, at least one resin selected from the group consisting of polyimide resins, polyamideimide resins, polyetherimide resins, and polyamide resins (aromatic polyamide resins and non-aromatic polyamide resins) is preferable. These polymers are particularly excellent in heat resistance, mechanical strength, chemical resistance, and electrical properties.

  The polymer constituting the porous film may be a polymer having a crosslinked structure. Such a polymer is, for example, a porous material containing a polymer having a crosslinkable functional group and a crosslinker capable of undergoing a crosslinking reaction with the crosslinkable functional group in the method for producing a porous film of the present invention described later. It can be obtained by forming a porous film using a material for forming a film and then causing a crosslinking reaction. A porous film using a polymer having a crosslinked structure is excellent in film strength, heat resistance, chemical resistance, and durability.

  Examples of the crosslinkable functional group include an amide group, a carboxyl group, an amino group, an isocyanate group, a hydroxyl group, an epoxy group, an aldehyde group, and an acid anhydride group.

  A polyimide-type resin can be manufactured by obtaining a polyamic acid (polyimide precursor) by reaction with a tetracarboxylic acid component and a diamine component, and imidating it further, for example. When the porous membrane is composed of a polyimide resin, the solubility becomes worse when imidized. Therefore, after first forming the porous membrane at the polyamic acid stage, imidization (thermal imidization, chemical imidization, etc.) Often done. Since the molecule of the polyimide precursor has many carboxyl groups and amide groups, these can be used as crosslinkable functional groups. In addition, the polyimide resin often has a carboxyl group, an amino group, or the like remaining at the terminal, and these can also be used as crosslinkable functional groups.

  The polyamide-imide resin can be usually produced by imidization after polymerization by reaction of trimellitic anhydride and diisocyanate or reaction of trimellitic anhydride chloride and diamine. Since the polyamideimide resin has many amide groups in the molecule, it can be used as a functional group capable of crosslinking. In addition, some imides remain reactive in the state of an unreacted precursor (amic acid), and the amide group or carboxyl group constituting this amic acid is used as a crosslinkable functional group. Can do. In addition, since the polyamideimide resin is produced by the above reaction, a carboxyl group, an isocyanate group, an amino group or the like often remains at the terminal, and these can be used as a functional group capable of crosslinking. .

  The polyetherimide resin can be produced, for example, by obtaining a polyamic acid by a reaction between an aromatic tetracarboxylic acid component having an ether bond and a diamine component, and further imidizing it. The amide group and carboxyl group constituting this amic acid can be used as a crosslinkable functional group. In addition, the polyetherimide resin often has a carboxyl group, an isocyanate group, an amino group, or the like remaining at the terminal, and these can also be used as crosslinkable functional groups.

  The polyamide-based resin can be produced by polycondensation of diamine and dicarboxylic acid, ring-opening polymerization of lactam, polycondensation of aminocarboxylic acid, or the like. Polyamide resins also include aromatic polyamide resins. Since the polyamide-based resin has a large number of amide groups in the molecule, it can be preferably used as a crosslinkable functional group. In addition, the polyamide resin often has a carboxyl group, an amino group, or the like remaining at the terminal, and these can be used as a functional group capable of crosslinking.

  The crosslinkable functional group may be present in the main chain of the resin or may be present in the side chain. Furthermore, it may exist in the middle of the molecular chain or may exist at the end. Moreover, the functional group which can be bridge | crosslinked may exist in rings, such as a benzene ring contained in polymer | macromolecule.

  The crosslinking agent is a compound that can react with a crosslinkable functional group of the polymer to form a crosslinked structure. Examples of the crosslinking agent include compounds having two or more epoxy groups, polyisocyanate compounds, silane coupling agents, melamine resins, phenol resins, urea resins, guanamine resins, alkyd resins, dialdehyde compounds, acid anhydrides, and the like. Can be mentioned. A crosslinking agent can be used individually or in combination of 2 or more types.

  The compound having two or more epoxy groups is a crosslinkable functional group possessed by the polymer, such as an amide group, a carboxyl group, an amino group, an isocyanate group, a hydroxyl group, an epoxy group, an aldehyde group, an acid. Can react with anhydride groups. The polyisocyanate compound can react with a crosslinkable functional group of the polymer, for example, a carboxyl group, an amino group, a hydroxyl group, an epoxy group, or an acid anhydride group. The silane coupling agent reacts with the crosslinkable functional group of the polymer, for example, amide group, carboxyl group, amino group, isocyanate group, hydroxyl group, epoxy group, aldehyde group, and acid anhydride group. sell. The melamine resin can react with a crosslinkable functional group possessed by the polymer, for example, an amino group, a hydroxyl group, or an aldehyde group. The phenol resin can react with a crosslinkable functional group possessed by the polymer, for example, a carboxyl group, an amino group, an isocyanate group, a hydroxyl group, an epoxy group, an aldehyde group, or an acid anhydride group. The urea resin can react with a crosslinkable functional group possessed by the polymer, for example, an amino group, a hydroxyl group, or an aldehyde group. The guanamine resin can react with a crosslinkable functional group of the polymer, for example, an aldehyde group. The alkyd resin can react with a crosslinkable functional group of the polymer, for example, a carboxyl group, an isocyanate group, a hydroxyl group, an epoxy group, or an acid anhydride group. The dialdehyde compound can react with a crosslinkable functional group of the polymer, for example, an amino group or a hydroxyl group. The acid anhydride can react with a crosslinkable functional group of the polymer, for example, an amino group, an isocyanate group, a hydroxyl group, or an epoxy group.

  Examples of a method of reacting a crosslinkable functional group in a polymer with a crosslinking agent include a method by heat and irradiation with active energy rays (visible light, ultraviolet rays, electron beams, radiation, etc.). The reaction with the cross-linking agent can proceed without a catalyst, but a catalyst can be added to promote the reaction.

  The blending ratio of the polymer having a crosslinkable functional group and the crosslinking agent is not particularly limited, and the desired degree of crosslinking, the kind of the polymer and the crosslinking agent, the functional group and the crosslinking agent, It is appropriately determined in consideration of the reactivity of For example, the compounding amount of the crosslinking agent is 2 to 312.5 parts by weight, preferably 10 to 200 parts by weight, more preferably 20 to 150 parts by weight with respect to 100 parts by weight of the polymer having a crosslinkable functional group. is there. If the amount of the crosslinking agent is too large, the crosslinking agent that does not contribute to the crosslinking reaction may remain in the porous film after the crosslinking treatment, and the characteristics of the porous film may be deteriorated.

  In the present invention, since the porous film contains titanium oxide particles, in addition to the porous function, functions such as reflection characteristics, aesthetics, adsorption characteristics (separation characteristics), wettability, photocatalytic activity, and high dielectric properties are provided. Have. Therefore, in addition to the hole characteristics, functions such as reflection characteristics, aesthetics, adsorption characteristics (separation characteristics), wettability, photocatalytic activity, and high dielectric properties can be imparted to the electrode using ITO.

  The average particle diameter of the primary particles of the titanium oxide particles is, for example, 0.01 to 10 μm, preferably 0.05 to 8 μm, and more preferably 0.1 to 3 μm. When the average particle diameter of the titanium oxide particles is too small, aggregation tends to occur and it becomes difficult to uniformly disperse in the polymer. Moreover, when the average particle diameter of the titanium oxide particles is too large, the pore structure formed by the polymer tends to be inhomogeneous.

  The content of titanium oxide particles in the porous membrane is, for example, 10 to 95% by weight, preferably 20 to 90% by weight, and more preferably 25 to 85% by weight. When the content of titanium oxide particles is too small, the effect of adding titanium oxide particles, that is, the functionality based on the titanium oxide particles is reduced. Conversely, when the content of titanium oxide particles is too large, the film tends to become brittle. .

  The thickness of the porous membrane is, for example, 5 to 200 μm, preferably 10 to 100 μm, and more preferably 15 to 50 μm. If the thickness is too thin, it is difficult to produce stably, and cushioning properties, printing characteristics, and mechanical strength may be reduced. On the other hand, when it is too thick, it becomes difficult to uniformly control the pore size distribution.

  In the present invention, the numerous micropores of the porous membrane may be independent micropores (independent micropores) with low communication or may be micropores with communication (continuous micropores). . Porous membranes with many independent micropores are suitable for applications that require heat insulation, cushioning, and impermeability, and porous membranes with many continuous micropores require permeability, adsorptivity, and high catalytic activity. Suitable for the intended use. The average pore diameter of the micropores in the porous membrane [in the case of a porous membrane having a large number of continuous micropores (a porous membrane having a Gurley value of 30 seconds / 100 cc or less), the average pore size on the surface of the porous membrane, In many porous membranes (porous membranes with a Gurley value exceeding 30 seconds / 100 cc), the average pore diameter of the micropores in the porous membrane] is 0.01 to 10 μm. The average pore diameter of the micropores is preferably 0.1 to 8 μm, more preferably 0.5 to 5 μm. If the average pore diameter of the micropores is out of the above range, it is difficult to obtain a desired effect according to the application. For example, when the average pore diameter of the micropores is too small, the permeation performance and strength are reduced. If the average pore size of the micropores is too large, it may be difficult to uniformly control the pore size distribution in the porous membrane, and the relative dielectric constant may be inhomogeneous at each part of the porous membrane. In addition, separation efficiency, reflection characteristics, adsorption characteristics, catalytic activity, and the like are likely to decrease. The maximum pore diameter on the porous membrane surface is preferably 15 μm or less.

  In the present invention, the porosity of the porous membrane (internal average porosity) is 30 to 85%, preferably 35 to 83%, and more preferably 40 to 80%. If the porosity of the porous membrane is out of the above range, desired pore characteristics depending on the application cannot be obtained. For example, if the porosity is too low, the permeation performance, adsorption characteristics, cushioning properties, etc. may not be sufficient, or the function may not be exhibited even if functional materials are filled. On the other hand, if the porosity is too high, the mechanical strength may be inferior.

  When the porous membrane has such an average pore diameter and porosity, the porous membrane has flexibility and excellent pore characteristics, but has excellent rigidity and handling properties.

  The porosity of the surface of the porous film (surface porosity) is, for example, 48% or more (for example, 48 to 80%), and preferably about 60 to 80%. If the surface area ratio is too low, the transmission performance may not be sufficient, and even if the pores are filled with a functional material, the function may not be fully achieved. It becomes easy to do.

  The connectivity of the micropores existing in the porous membrane can be determined by using the Gurley value representing the air permeability and the pure water permeation rate as an index. The Gurley value of the porous film having a thickness of 30 μm is, for example, 0.2 to 30 seconds / 100 cc, preferably 0.5 to 25 seconds / 100 cc, more preferably 0.8 to 20 seconds / 100 cc, and particularly preferably 1 to 1. 10 seconds / 100 cc. If the numerical value is too large, the practical permeation performance may not be sufficient, or the functional material may not be sufficiently filled and the function may not be exhibited. On the other hand, if the value is too small, the mechanical strength may be inferior.

  The pore size, porosity, air permeability, and porosity of the porous membrane are determined in the method for producing a titanium oxide-containing porous membrane laminate described later, the type and amount of water-soluble polymer, the amount of water used, It can be adjusted to a desired value by appropriately selecting the humidity, temperature, time, etc. during casting.

The titanium oxide-containing porous membrane laminate of the present invention, for example, does not cause interfacial separation between the film with ITO transparent conductive film and the porous membrane layer when a tape peeling test based on the following method is performed. preferable. That is, it is preferable that the ITO transparent conductive film-attached film and the porous film layer are directly laminated with an interlayer adhesion strength that does not cause interface peeling in the following tape peeling test.
Tape peel test:
On the surface of the porous film layer of the laminate, a masking tape [film masking tape No. 603 (# 25)] is applied for a length of 50 mm from one end of the tape, and the attached tape is a roller having a diameter of 30 mm and a load of 200 gf (Holbein Art Materials Inc., oil resistant hard rubber roller No. 10). Then, the other end of the tape is pulled at a peeling speed of 50 mm / min using a tensile tester to perform T-type peeling.

  Since the titanium oxide-containing porous film laminate of the present invention has a structure in which a flexible porous film is laminated on a film with a high strength ITO transparent conductive film, the above-described excellent pore characteristics and titanium oxide particles As well as having the characteristics of, it has sufficient folding resistance. The folding resistance is evaluated by repeatedly performing a bending test based on the following conditions and having folding resistance when the number of times until the test material is cut is 10 times or more. In addition, it is judged that the higher the number of folds until cutting, the better the folding resistance. For example, in applications where repeated bending is required for electronic materials, etc., the number of folds is about 100 or more. It is preferable. The bending test uses an MIT fatigue resistance tester MIT-D manufactured by Toyo Seiki Seisakusho, sample shape 15 × 110 mm, bending angle 135 °, bending radius of curvature (R) 0.38 mm, bending speed 175 cpm, tension It is performed according to the fold resistance test of JIS C 5016 under the condition of 4.9N.

  According to the titanium oxide-containing porous membrane laminate of the present invention, those that are not cut even when the number of folding times is 20000 times and that have extremely excellent folding resistance are included. For this reason, excellent workability and moldability can be exhibited, and it can be used in a wide variety of applications in various forms.

  A particularly preferred form of the titanium oxide-containing porous membrane laminate of the present invention contains a titanium oxide having a porous membrane layer having fine pores with high communication and an average pore diameter of 0.01 to 10 μm. It is a porous film laminate, the thickness of the porous film layer is 5 to 200 μm, the porosity is 30 to 85%, and the thickness of the film with the ITO transparent conductive film is 1 to 300 μm. Such a titanium oxide-containing porous membrane laminate can be produced by appropriately setting the material, thickness, production conditions (for example, humidification conditions) and the like that constitute the porous membrane layer and the film with the ITO transparent conductive film.

[Production of titanium oxide-containing porous membrane laminate]
The titanium oxide containing porous membrane laminated body of this invention can be manufactured using a phase change method. That is, a dispersion of a porous film-forming material containing a polymer to form a porous film (porous film layer) and inorganic particles is transferred onto the ITO transparent conductive film of the ITO transparent conductive film. Can be produced by immersing it in a coagulating liquid and then subjecting it to drying.

  The dispersion of the porous film-forming material (hereinafter sometimes simply referred to as “dispersion”) includes, for example, a polymer component, titanium oxide particles, and a water-soluble polar solvent that are the main materials constituting the porous film. And optionally contains a water-soluble polymer, water if necessary, and a crosslinking agent (if a crosslinked structure is formed in the molecule of the polymer) if necessary. In the dispersion, instead of the polymer component constituting the porous membrane, a monomer component of the polymer component, an oligomer thereof, a precursor before imidization or cyclization, or the like may be used. .

  Adding a water-soluble polymer or water to the dispersion is effective for making the membrane structure porous. Examples of the water-soluble polymer include polyethylene glycol, polyvinyl pyrrolidone, polyethylene oxide, polyvinyl alcohol, polyacrylic acid, polysaccharides, and derivatives thereof. These water-soluble polymers can be used alone or in combination of two or more. Among these, polyvinylpyrrolidone is particularly preferable from the viewpoint of the connectivity of the micropores present in the porous membrane. In order to make it porous, the weight average molecular weight of the water-soluble polymer should be 200 or more, preferably 300 or more, more preferably 1000 or more, and particularly preferably 5000 or more (for example, 5000 to 200,000). The pore size can be adjusted by the amount of water added. For example, the pore size can be increased by increasing the amount of water added to the dispersion.

  The water-soluble polymer is very effective for making the membrane structure into a homogeneous sponge-like porous structure, and various structures can be obtained by changing the kind and amount of the water-soluble polymer. For this reason, the water-soluble polymer is very suitably used as an additive for forming a porous film for the purpose of imparting desired pore characteristics.

  On the other hand, the water-soluble polymer is an unnecessary component to be removed that does not ultimately form a porous film. In the method of the present invention using the wet phase conversion method, the water-soluble polymer is removed by washing in a step of phase conversion by dipping in a coagulating liquid such as water. On the other hand, in the dry phase inversion method, components that do not constitute a porous membrane (unnecessary components) are removed by heating, and water-soluble polymers are usually unsuitable for removal by heating, so use them as additives. Is extremely difficult. Thus, while it is difficult to form various pore structures depending on the dry phase conversion method, the production method of the present invention can easily produce a porous film having desired pore characteristics. Is advantageous in that it is possible.

  In the method of the present invention, when the amount of the water-soluble polymer added is increased, the pore connectivity tends to increase. Therefore, when it is desired to obtain a porous membrane with low connectivity (a porous membrane having many independent micropores), it is preferable to minimize the amount of the water-soluble polymer, and it is also possible not to use the water-soluble polymer. is there.

  Examples of the water-soluble polar solvent include dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), 2-pyrrolidone, and γ-butyrolactone. In addition, those having solubility (good solvent for the polymer component) can be used according to the chemical skeleton of the polymer used as the polymer component. These solvents can be used alone or in combination of two or more.

  The amount of each component in the dispersion is 8 to 25% by weight of the polymer component, 0 to 25% by weight of the cross-linking agent, 10 to 50% by weight of the water-soluble polymer, and 0 to 0% by weight of water based on the dispersion. It is preferable to set it as 10 weight% and 30-82 weight% of water-soluble polar solvents. At this time, if the concentration of the polymer component is too low, the thickness of the porous membrane becomes insufficient, the desired pore characteristics are difficult to obtain, and the strength of the porous membrane tends to be weak, while If the concentration of the molecular component is too high, the porosity tends to decrease. If the concentration of the water-soluble polymer is too low, huge voids exceeding 10 μm are generated inside the porous membrane, and the homogeneity tends to be lowered. If the concentration of the water-soluble polymer is too high, problems such as poor solubility of each component and a decrease in the strength of the porous membrane are likely to occur.

  The dispersion of the porous film-forming material is cast into a film on the ITO transparent conductive film of the ITO transparent conductive film, and then immersed in a coagulating liquid for phase conversion.

  The coagulation liquid used in the phase change method may be any solvent (non-solvent for the polymer component) that coagulates the polymer component, and is appropriately selected depending on the type of polymer used as the polymer component. Monohydric alcohols such as methanol and ethanol, alcohols such as polyhydric alcohols such as glycerin; water-soluble polymers such as polyethylene glycol; water-soluble coagulating liquids such as a mixture thereof can be used.

  The temperature of the coagulation liquid is not particularly limited, but is preferably in the range of 0 to 100 ° C, for example. When the temperature of the coagulation liquid is less than 0 ° C., the cleaning effect of a solvent or the like tends to be lowered. When the temperature of the coagulating liquid exceeds 100 ° C., the solvent and the coagulating liquid are volatilized and the working environment is impaired. As the coagulating liquid, water is preferably used from the viewpoints of cost, safety and the like. When water is used as the coagulation liquid, a temperature of water of about 5 to 60 ° C. is appropriate. The immersion time in the coagulation liquid is not particularly limited, but the time for sufficiently washing the water-soluble polar solvent and the water-soluble polymer is appropriately selected. If the washing time is too short, the porous structure may be broken in the drying process due to the remaining solvent. If the cleaning time is too long, the production efficiency is lowered and the product cost is increased. Since the cleaning time depends on the thickness of the porous film and the like, it cannot be generally specified, but can be about 0.5 to 30 minutes.

  Before immersing the film-like material after casting in the coagulating liquid, the film-like material after casting is 0.2 minutes or more (for example, in an atmosphere consisting of a relative humidity of 70 to 100% and a temperature of 15 to 100 ° C. 0.2 to 180 minutes), preferably 0.2 to 60 minutes, more preferably 0.2 to 15 minutes), and then led into the coagulation liquid. By placing the film-like material after casting under the above humidification conditions, a highly homogeneous porous membrane can be easily obtained. When placed under humidification, it is considered that moisture penetrates from the film surface to the inside, and promotes layer separation of the dispersion efficiently. Therefore, it is guessed that the open area ratio of the surface (the air side surface of a porous film) on the opposite side to the film side surface with an ITO transparent conductive film of a porous film improves. Preferred conditions are a relative humidity of 90 to 100% and a temperature of 30 to 80 ° C., and a more preferred condition is a relative humidity of about 100% (eg, 95 to 100%) and a temperature of 40 to 70 ° C.

  Next, the film with the ITO transparent conductive film on which the film-like porous layer is laminated is taken out from the coagulation liquid and dried. The method for the drying treatment is not particularly limited, and is not particularly limited as long as it is a method capable of removing a solvent component such as a coagulation liquid, and may be heated or naturally dried at room temperature. The method for the heat treatment is not particularly limited, and may be a hot air treatment, a hot roll treatment, or a method of putting it in a thermostatic bath, an oven, or the like, as long as the porous film laminate can be controlled to a predetermined temperature. The heating temperature can be selected from a wide range of room temperature to about 600 ° C., for example. The atmosphere during the heat treatment may be air, nitrogen or an inert gas. The use of air is the least expensive but may involve an oxidation reaction. In order to avoid this, nitrogen or an inert gas is preferably used, and nitrogen is preferable from the viewpoint of cost. The heating conditions are appropriately set in consideration of productivity, physical properties of the porous membrane layer and the substrate, and the like. By subjecting to drying, a titanium oxide-containing porous film laminate in which the porous film layer is directly formed on the surface of the ITO transparent conductive film-attached film can be obtained.

  The titanium oxide-containing porous membrane laminate thus obtained may be further subjected to a crosslinking treatment using heat, visible light, ultraviolet rays, electron beams, radiation, or the like. Lamination having a porous membrane layer with improved properties such as rigidity and chemical resistance by polymerizing, crosslinking, curing, etc. of the precursor constituting the porous membrane layer to form a polymer compound by the treatment. You can get a body. For example, a polyimide porous membrane layer can be obtained by subjecting a porous membrane layer formed using a polyimide precursor to thermal imidization or chemical imidization. The porous membrane layer formed using the polyamide-imide resin can be subjected to thermal crosslinking. The thermal crosslinking can also be performed simultaneously with the heat treatment for drying after being led to the coagulation liquid. Even when a cross-linking agent is added to the dispersion of the porous film-forming material, the cross-linking reaction proceeds by the same treatment as above, and a cross-linked structure is formed in the polymer molecule.

  In addition, when various functional layers described later are formed on the surface of the porous membrane (porous membrane layer) of the titanium oxide-containing porous membrane laminate, the following (b) and (c) If cross-linking occurs during the formation of the functional layer (functional expression), it is effective for improving the adhesion between the porous film and the functional layer.

When a functional layer is provided on the surface of the porous membrane (functionalization treatment) to obtain a functional laminate, there is a timing for performing the following crosslinking treatment.
(A) The obtained porous film (porous film formed on a film with an ITO transparent conductive film) is subjected to a crosslinking treatment, and then a functional layer is provided on the surface of the porous film to form a functional laminate. Method (b) A method in which a functional layer is provided on the surface of the obtained porous film (porous film formed on a film with an ITO transparent conductive film), and then a crosslinking treatment is performed to obtain a functional laminate. (Crosslinking treatment by heating may also serve as heat treatment for functionalization of the functional layer)
(C) The obtained porous film (porous film formed on the film with ITO transparent conductive film) is subjected to a partial crosslinking treatment, and then a functional layer is provided on the surface of the porous film, and again, A method of obtaining a functional laminate by carrying out the crosslinking treatment of [the partial crosslinking treatment is intended to be a semi-cured state (so-called B stage)]

  The porous film in the titanium oxide-containing porous film laminate of the present invention may be subjected to heat treatment or film formation treatment as necessary in order to impart desired characteristics.

  According to the method for producing a titanium oxide-containing porous membrane laminate of the present invention, on the ITO transparent conductive film of the ITO transparent conductive film, for example, the average pore diameter is 0.01 to 10 μm, and the porosity is 30 to 30. A laminate in which a titanium oxide-containing porous membrane layer having a thickness of 85% and a thickness of about 5 to 200 μm is formed can be easily obtained. The pore size, porosity, etc. of the porous membrane are set to desired values by appropriately selecting the type and amount of the constituents of the dispersion, the amount of water used, the humidity during casting, the temperature, the time, and the like. Can be adjusted.

  In the porous membrane in the titanium oxide-containing porous membrane laminate of the present invention, the porous membrane may be coated with a chemical resistant polymer compound.

  Here, the chemical is known as a material that dissolves, swells, shrinks, and decomposes a resin that constitutes a conventional porous film to lower its function as a porous film. The specific examples of such chemicals are dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methyl. Strong polar solvent such as 2-pyrrolidone (NMP), 2-pyrrolidone, cyclohexanone, acetone, methyl acetate, ethyl acetate, ethyl lactate, acetonitrile, methylene chloride, chloroform, tetrachloroethane, tetrahydrofuran (THF); alkaline solution; acidic Solutions; and mixtures thereof. The alkaline solution includes inorganic salts such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, and potassium carbonate; amines such as triethylamine; aqueous solutions and organic solvent solutions in which alkaline substances such as ammonia are dissolved. . Examples of the acidic solution include aqueous solutions and organic solvent solutions in which acids such as inorganic acids such as hydrogen chloride, sulfuric acid, and nitric acid; and organic acids such as carboxylic acids such as acetic acid and phthalic acid are dissolved.

  The chemical resistant polymer compound is not particularly limited as long as it has excellent resistance to chemicals such as strong polar solvents, alkalis, acids, etc. For example, phenolic resin, xylene resin, urea resin, melamine Thermosetting resin such as resin, benzoguanamine resin, benzoxazine resin, alkyd resin, triazine resin, furan resin, unsaturated polyester, epoxy resin, silicon resin, polyurethane resin, polyimide resin, or light Curable resin: Thermoplastic resins such as polyvinyl alcohol, cellulose acetate resin, polypropylene resin, fluorine resin, phthalic acid resin, maleic acid resin, saturated polyester, ethylene-vinyl alcohol copolymer, chitin, chitosan, etc. Is mentioned. These polymer compounds can be used alone or in combination of two or more. The polymer compound may be a copolymer or a graft polymer.

  When a porous film is coated with such a chemical-resistant polymer compound, the porous film dissolves or swells and deforms even when it comes into contact with the strong polar solvent, alkali, acid, or other chemicals. The alteration can be suppressed to such an extent that no alteration occurs, such as when it occurs, or there is no influence on the purpose of use or the use. For example, in an application where the porous membrane and the chemical are in contact with each other for a short time, it is only necessary to provide chemical resistance that does not change within that time.

  In addition, since the said chemical-resistant high molecular compound has many heat resistances simultaneously, there is little possibility that the heat resistance of a porous film | membrane may fall. It is also possible to change the properties of the porous membrane surface by coating with a chemical resistant polymer compound. For example, if a fluororesin is used, the surface can be made water repellent, and if an ethylene-vinyl alcohol copolymer is used, the surface can be made hydrophilic. Furthermore, if a phenolic resin is used, the surface can be rendered water repellent with respect to neutral water and the surface can be rendered hydrophilic with respect to an alkaline aqueous solution. Thus, the affinity (hydrophilicity etc.) with respect to a liquid can be changed by selecting suitably the kind of chemical-resistant high molecular compound used for coating | cover.

[Functional laminate (composite material)]
Functional layers such as a conductor layer, a dielectric layer, a semiconductor layer, an insulator layer, and a resistor layer can be provided on the surface of the porous membrane layer of the titanium oxide-containing porous membrane laminate of the present invention. . Thus, by providing a conductor layer on the surface of the porous membrane layer of the titanium oxide-containing porous membrane laminate, in addition to the pore properties of the porous membrane and the functional properties of the titanium oxide particles, the Can be added. Since such a functional laminate has a plurality of functions, it can be used for various purposes in a wider field. In the present specification, a functional laminate in which a functional layer is provided on the surface of the porous membrane layer of the laminate is sometimes referred to as a “composite material”.

  Formation of various functional layers or precursor layers thereof on the surface of the porous film layer of the laminate can be performed by, for example, plating, printing technology, or the like. The layer formed by plating includes a metal plating layer and a magnetic plating layer.

  The metal plating layer may be formed, for example, as a thin metal coating on the surface of the porous film layer of the laminate (sometimes simply referred to as “porous film”). Examples of the metal constituting the metal plating layer include copper, nickel, silver, gold, tin, bismuth, zinc, aluminum, lead, chromium, iron, indium, cobalt, rhodium, platinum, palladium, and alloys thereof. be able to. In addition, nickel-phosphorus, nickel-copper-phosphorus, nickel-iron-phosphorus, nickel-tungsten-phosphorus, nickel-molybdenum-phosphorus, nickel-chromium-phosphorus, nickel-boron-phosphorus, etc. An alloy film can also be mentioned. The metal plating layer may be used alone or in combination of the above metals, may be a single layer, or a plurality of layers may be laminated.

  The material constituting the magnetic plating layer is not particularly limited as long as it is a compound having magnetism, and may be either a ferromagnetic material or a paramagnetic material. For example, nickel-cobalt, cobalt-iron-phosphorus, cobalt- Alloys such as tungsten-phosphorus, cobalt-nickel-manganese; compounds having a site capable of generating radicals, such as methoxyacetonitrile polymer, metal complex compounds such as charge transfer complexes of decamethylferrocene, and carbon materials under graphitization An organic magnetic material composed of a compound such as polyacrylonitrile can be exemplified.

  For example, a known method such as electroless plating or electrolytic plating can be used to form the metal plating layer. In the present invention, electroless plating is preferably used from the viewpoint that the porous film is composed of a polymer component, and a combination of electroless plating and electrolytic plating can also be used.

  The plating solutions used for forming the metal plating layer are known in various compositions, and those sold by manufacturers can also be obtained. The composition of the plating solution is not particularly limited, and various requests (aesthetics, hardness, abrasion resistance, discoloration resistance, corrosion resistance, electrical conductivity, thermal conductivity, heat resistance, sliding property, water repellency, wettability) The soldering wettability, sealing properties, electromagnetic wave shielding characteristics, reflection characteristics, etc. may be selected.

  One embodiment of a method for producing a composite material includes a step of applying a photosensitive composition comprising a compound that generates a reactive group by light to the surface of the porous film to provide a photosensitive layer, and the photosensitive layer through a mask. A method comprising: exposing and forming a reactive group in the exposed portion; and bonding the reactive group generated in the exposed portion with a metal to form a conductor pattern; or A method comprising a step of using a compound that loses a reactive group by light instead of a compound to be generated, a step of eliminating the reactive group in an exposed portion, and a step of forming a conductor pattern by combining a reactive group remaining in an unexposed portion with a metal. Done.

  The compound that generates a reactive group by light is not particularly limited as long as it is a compound that generates a reactive group in a molecule that can form a bond with a metal (including a metal ion). For example, an onium salt derivative or a sulfonium ester And photosensitive compounds containing at least one derivative selected from derivatives, carboxylic acid derivatives and naphthoquinonediazide derivatives. These photosensitive compounds are versatile and can easily generate a reactive group capable of binding to a metal by light irradiation, so that a conductive portion having a fine pattern can be accurately formed.

  As a compound that loses a reactive group by light, for example, a compound having a reactive group capable of forming a bond with a metal (including a metal ion), and the reactive group generates a hydrophobic functional group by irradiation with light. And compounds that are difficult to dissolve or swell in water.

The reactive group generated or disappeared by the light is not particularly limited as long as it is a reactive group capable of forming a bond with the metal (including a metal ion), and examples thereof include a functional group capable of ion exchange with a metal ion. Preferably, a cation exchange group is used. The cation exchange group includes an acidic group such as a —COOX group, a —SO ₃ X group or a —PO ₃ X ₂ group (where X is a hydrogen atom, an alkali metal, an alkaline earth metal, or an ammonium group). ) Etc. are included. Among them, a cation exchange group having a pKa value of 7.2 or less is preferable because it can form a bond with a sufficient metal per unit area, and can easily obtain desired conductivity. Such a reactive group is subjected to metal ion exchange in the next step, and can exhibit a stable adsorption ability by a metal reductant or metal fine particles.

  The irradiation light is not particularly limited as long as the generation or disappearance of the reactive group can be promoted. For example, light having a wavelength of 280 nm or more can be used. However, in order to avoid deterioration due to exposure of the porous film, the wavelength is preferably 300 nm or more. (About 300 to 600 nm) In particular, light of 350 nm or more is preferably used.

  By irradiating with light through a mask and then washing as necessary, a pattern composed of reactive groups can be formed in the exposed or unexposed areas. In this way, the reactive group provided on the surface of the porous membrane is bonded to a metal by the method described below to form a conductor pattern.

  In the present invention, an electroless plating method is preferably used as a method for bonding the reactive group to the metal. Electroless plating is known to be useful as a method of laminating a metal on a resin layer generally formed of plastic or the like. The surface of the porous membrane may be subjected to treatments such as degreasing, washing, neutralization, and catalytic treatment in advance for the purpose of improving the adhesion with the metal. As the catalyst treatment, for example, a catalyst metal nucleation method in which a catalyst metal capable of promoting metal deposition is attached to the surface to be treated can be used. The catalytic metal nucleation method is a method of promoting chemical plating by contacting a colloidal solution containing a catalytic metal (salt) and then contacting an acid or alkali solution or a reducing agent (catalyzer (catalyst) -accelerator). Method): A method of forming a catalytic metal nucleus by contacting a colloidal solution containing fine particles of catalytic metal and then removing the solvent and additives by heating or the like (metal fine particle method); An acid or alkali solution containing a reducing agent And then contacting the catalyst metal with an acid or alkali solution and bringing the catalyst into contact with an activating liquid (sensitizing)-activating (activating) ) Method).

  As the catalyst metal (salt) -containing solution in the catalyzer-accelerator method, for example, a metal (salt) -containing solution such as a tin-palladium mixed solution or copper sulfate can be used. The catalyzer-accelerator method is, for example, by immersing the laminate in an aqueous copper sulfate solution, washing and removing excess copper sulfate as necessary, and then immersing in an aqueous solution of sodium borohydride. In addition, a catalyst nucleus composed of copper fine particles can be formed. In the metal fine particle method, for example, a colloidal solution in which silver nanoparticles are dispersed is brought into contact with the surface of the porous film, and then heated to remove additives such as a surfactant and a binder, whereby the surface of the porous film is removed. Catalyst nuclei made of silver particles can be deposited. In the sensitizing-activating method, for example, after contacting with a hydrochloric acid solution of tin chloride, a catalyst nucleus made of palladium can be precipitated by contacting with a hydrochloric acid solution of palladium chloride. As a method of bringing the porous film into contact with these treatment liquids, a method of applying a metal plating layer on the porous film surface, a method of immersing the laminate in the treatment liquid, or the like can be used.

  Examples of main metals used for electroless plating include copper, nickel, silver, gold, nickel-phosphorus, and the like. The plating solution used for electroless plating contains, for example, the above metals or salts thereof, reducing agents such as formaldehyde, hydrazine, sodium hypophosphite, sodium borohydride, ascorbic acid, glyoxylic acid, acetic acid It contains complexing agents and precipitation control agents such as sodium, EDTA, tartaric acid, malic acid, citric acid and glycine, and many of these are commercially available and can be easily obtained. Electroless plating is performed by immersing the laminate subjected to the above treatment in the above plating solution.

  The thickness of the metal plating layer is not particularly limited and can be appropriately selected depending on the application, and is, for example, about 0.01 to 20 μm, preferably about 0.1 to 10 μm. In order to efficiently increase the thickness of the metal plating layer, for example, a method of forming a metal plating layer by combining electroless plating and electrolytic plating may be performed. In other words, since the surface of the porous film layer on which the metal film is formed by electroless plating is imparted with conductivity, it is possible to obtain a thick metal plating layer in a short time by applying more efficient electrolytic plating. It becomes.

  The above method is particularly suitable as a method for obtaining a composite material used for a circuit board, a heat dissipation material, or an electromagnetic wave control material.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

  The average pore diameter and porosity of the micropores of the porous membrane were calculated and measured by the following methods. The average pore diameter and the porosity are obtained only for the micropores visible in the electron micrograph.

1. Average pore diameter From the electron micrograph, the area of any 30 or more pores on the surface or cross section of the porous membrane was measured, and the average value was defined as the average pore area Save. Assuming that the hole is a perfect circle, the value converted from the average hole area to the hole diameter using the following formula was defined as the average hole diameter. Here, π represents the circumference ratio.
Surface or internal average pore diameter [μm] = 2 × (Save / π) ^1/2

2. Porosity The porosity inside the porous membrane was calculated by the following formula. V is the volume of the porous membrane [cm ³ ], W is the weight of the porous membrane [g], ρ is the density of the porous membrane composition [g / cm ³ ] (where the density of the porous membrane composition is And a density calculated by distributing the density of each component constituting the composition by weight composition ratio).
Porosity [%] = 100-100 × W / (ρ · V)
In addition, the density of each component in the porous membrane composition used in the Example is as follows.
Density of polyamideimide (trade name “Bilomax HR-11NN”): 1.45 [g / cm ³ ]
Density of polyetherimide (trade name “Ultem 1000”): 1.27 [g / cm ³ ]
Density of titanium oxide (trade name “R-45M”): 3.9 [g / cm ³ ]
Density of titanium oxide (trade name “CR-50”): 4.1 [g / cm ³ ]

Example 1
Polyetherimide resin (trade name “Ultem 1000” manufactured by SABIC Innovative Plastics), N-methyl-2-pyrrolidone (NMP) as a solvent, and the weight ratio of polyetherimide resin / NMP is 18/82. A polyetherimide resin solution was prepared by mixing at a ratio. In this liquid, 20 parts by weight of polyvinylpyrrolidone (molecular weight 50,000) as a water-soluble polymer, and titanium oxide (trade name “R-45M” manufactured by Sakai Chemical Industry Co., Ltd., rutile type, average particle size 0.29 μm) 9 parts by weight Parts were mixed at a ratio such that the weight ratio of polyetherimide resin / NMP / polyvinylpyrrolidone / titanium oxide was 18/82/20/9 to obtain a stock solution (dispersion) for film formation.
On a glass plate, a PET film with an ITO transparent conductive film (manufactured by Tobi Corporation, trade name “OTEC-130”, thickness 125 μm) was fixed with tape so that the ITO transparent conductive film surface was on the outside, and the temperature was 25 ° C. The stock solution was cast using a film applicator under the condition of a gap of 102 μm between the film applicator and the PET film with an ITO transparent conductive film. Immediately after casting, it was kept in a container having a humidity of about 100% and a temperature of 50 ° C. for 4 minutes. Then, after being immersed in water and solidified, it was taken out from water and naturally dried at room temperature to obtain a laminate in which a titanium oxide-containing porous film was laminated on a PET film with an ITO transparent conductive film. The adhesion of the titanium oxide-containing porous film to the PET film with the ITO transparent conductive film was good (see the evaluation test described later). Moreover, the obtained laminated body was excellent also in the softness | flexibility. Of the obtained laminate, the thickness of the porous layer was 37 μm.
When the porous film of this laminate was observed with an electron microscope, the inside of the porous film was almost homogeneous, and there existed micropores having an average pore diameter of 1 μm over the entire area. The porosity inside the porous membrane was 70%. The content of inorganic particles in the porous membrane is 33.3% by weight.

Example 2
Instead of titanium oxide (trade name “R-45M” manufactured by Sakai Chemical Industry Co., Ltd., rutile type, average particle size 0.29 μm), titanium oxide (trade name “CR-50” manufactured by Ishihara Sangyo Co., Ltd., rutile type, The same operation as in Example 1 was performed except that the weight ratio of polyetherimide resin / NMP / polyvinylpyrrolidone / titanium oxide in the stock solution was 18/82/20/27. The laminated body by which the titanium oxide containing porous film was laminated | stacked on PET film with an ITO transparent conductive film was obtained. The adhesion of the titanium oxide-containing porous film to the PET film with the ITO transparent conductive film was good (see the evaluation test described later). Moreover, the obtained laminated body was excellent also in the softness | flexibility. Of the obtained laminate, the thickness of the porous layer was 56 μm.
When the porous film of this laminate was observed with an electron microscope, the inside of the porous film was almost homogeneous, and there existed micropores having an average pore diameter of 1 μm over the entire area. The porosity inside the porous membrane was 66%. The content of inorganic particles in the porous membrane is 60% by weight.

Example 3
Instead of titanium oxide (trade name “R-45M” manufactured by Sakai Chemical Industry Co., Ltd., rutile type, average particle size 0.29 μm), titanium oxide (trade name “CR-50” manufactured by Ishihara Sangyo Co., Ltd., rutile type, The average particle diameter was 0.25 μm), and the same operation as in Example 1 was performed except that the weight ratio of polyetherimide resin / NMP / polyvinylpyrrolidone / titanium oxide in the stock solution was 18/82/20/42. The laminated body by which the titanium oxide containing porous film was laminated | stacked on PET film with an ITO transparent conductive film was obtained. The adhesion of the titanium oxide-containing porous film to the PET film with the ITO transparent conductive film was good (see the evaluation test described later). Moreover, the obtained laminated body was excellent also in the softness | flexibility. Of the obtained laminate, the thickness of the porous layer was 52 μm.
When the porous film of this laminate was observed with an electron microscope, the inside of the porous film was almost homogeneous, and there existed micropores having a communication with an average pore diameter of 2 μm over the entire area. The porosity inside the porous membrane was 64%. The content of inorganic particles in the porous membrane is 70% by weight.
The electron micrograph (SEM photograph) of the porous membrane surface in the obtained laminated body is shown in FIG. In FIG. 1, black portions are holes, gray portions are resins, and white portions are titanium oxide particles.

Example 4
Instead of titanium oxide (trade name “R-45M” manufactured by Sakai Chemical Industry Co., Ltd., rutile type, average particle size 0.29 μm), titanium oxide (trade name “CR-50” manufactured by Ishihara Sangyo Co., Ltd., rutile type, The same operation as in Example 1 was performed except that the weight ratio of polyetherimide resin / NMP / polyvinylpyrrolidone / titanium oxide in the stock solution was 18/82/20/72. The laminated body by which the titanium oxide containing porous film was laminated | stacked on PET film with an ITO transparent conductive film was obtained. The adhesion of the titanium oxide-containing porous film to the PET film with the ITO transparent conductive film was good (see the evaluation test described later). Moreover, the obtained laminated body was excellent also in the softness | flexibility. Of the obtained laminate, the thickness of the porous layer was 57 μm.
When the porous film of this laminate was observed with an electron microscope, the inside of the porous film was almost homogeneous, and there existed micropores having an average pore diameter of 1 μm over the entire area. The porosity inside the porous membrane was 63%. The content of inorganic particles in the porous membrane is 80% by weight.

Example 5
Instead of titanium oxide (trade name “R-45M” manufactured by Sakai Chemical Industry Co., Ltd., rutile type, average particle size 0.29 μm), titanium oxide (trade name “CR-50” manufactured by Ishihara Sangyo Co., Ltd., rutile type, The same operation as in Example 1 was performed except that the weight ratio of polyetherimide resin / NMP / polyvinylpyrrolidone / titanium oxide in the stock solution was 18/82/20/102. The laminated body by which the titanium oxide containing porous film was laminated | stacked on PET film with an ITO transparent conductive film was obtained. The adhesion of the titanium oxide-containing porous film to the PET film with the ITO transparent conductive film was good (see the evaluation test described later). Moreover, the obtained laminated body was excellent also in the softness | flexibility. Of the obtained laminate, the thickness of the porous layer was 46 μm.
When the porous film of this laminate was observed with an electron microscope, the inside of the porous film was almost homogeneous, and there existed micropores having an average pore diameter of 1 μm over the entire area. The porosity inside the porous membrane was 64%. The content of inorganic particles in the porous membrane is 85% by weight.

Example 6
Polyamideimide resin solution (trade name “Vilomax HR-11NN” manufactured by Toyobo Co., Ltd .; solid content concentration 15% by weight, solvent NMP, solution viscosity 20 dPa · s / 25 ° C.) as a water-soluble polymer 30 parts by weight of polyvinylpyrrolidone (molecular weight 50,000) and 22.5 parts by weight of titanium oxide (trade name “CR-50” manufactured by Ishihara Sangyo Co., Ltd., rutile type, average particle diameter of 0.25 μm) NMP / polyvinylpyrrolidone / titanium oxide was mixed at a weight ratio of 15/85/30 / 22.5 to obtain a stock solution (dispersion) for film formation.
On a glass plate, a PET film with an ITO transparent conductive film (manufactured by Tobi Corporation, trade name “OTEC-130”, thickness 125 μm) was fixed with tape so that the ITO transparent conductive film surface was on the outside, and the temperature was 25 ° C. The stock solution was cast using a film applicator under the condition of a gap of 102 μm between the film applicator and the PET film with an ITO transparent conductive film. Immediately after casting, it was kept in a container having a humidity of about 100% and a temperature of 50 ° C. for 4 minutes. Then, after being immersed in water and solidified, it was taken out from water and naturally dried at room temperature to obtain a laminate in which a titanium oxide-containing porous film was laminated on a PET film with an ITO transparent conductive film. The adhesion of the titanium oxide-containing porous film to the PET film with the ITO transparent conductive film was good (see the evaluation test described later). Moreover, the obtained laminated body was excellent also in the softness | flexibility. Of the obtained laminate, the thickness of the porous layer was 40 μm.
When the porous film of this laminated body was observed with an electron microscope, the inside of the porous film was almost homogeneous, and there existed micropores having connectivity with an average pore diameter of 0.5 μm over the entire area. The porosity inside the porous membrane was 75%. The content of inorganic particles in the porous membrane is 60% by weight.
The electron micrograph (SEM photograph) of the surface of the porous film of the obtained laminated body is shown in FIG. In FIG. 2, black portions are holes, gray portions are resins, and white portions are titanium oxide particles.

Comparative Example 1
A PET film substrate (manufactured by Teijin DuPont, HS74AS type, thickness 100 μm) was fixed on a glass plate with a tape so that the easy-adhesion surface of the PET film was on the outside instead of the PET film with an ITO transparent conductive film. Except that, the same operation as in Example 3 was performed. Immediately after casting, the porous layer was naturally peeled off from the PET film substrate when it was kept in a container having a humidity of about 100% and a temperature of 50 ° C. for 4 minutes and then immersed in water to solidify. Therefore, the laminated body by which the titanium oxide containing porous membrane was laminated | stacked on the PET film base material was not obtained.
The obtained porous layer was naturally dried at room temperature to obtain a film consisting only of the porous layer. The thickness of the film made of only the obtained porous layer was 36 μm.
When this porous film was observed with an electron microscope, the inside of the porous film was almost homogeneous, and there existed micropores having an average pore diameter of 2 μm over the entire area. The porosity inside the porous membrane was 66%. The content of inorganic particles in the porous membrane is 70% by weight.

Comparative Example 2
A PET film substrate (manufactured by Teijin DuPont, HS74AS type, thickness 100 μm) was fixed on a glass plate with a tape so that the easy-adhesion surface of the PET film was on the outside instead of the PET film with an ITO transparent conductive film. Except that, the same operation as in Example 6 was performed. Immediately after casting, the porous layer was naturally peeled off from the PET film substrate when it was kept in a container having a humidity of about 100% and a temperature of 50 ° C. for 4 minutes and then immersed in water to solidify. Therefore, the laminated body by which the titanium oxide containing porous membrane was laminated | stacked on the PET film base material was not obtained.
The obtained porous layer was naturally dried at room temperature to obtain a film consisting only of the porous layer. The thickness of the film consisting only of the obtained porous layer was 50 μm.
When this porous membrane was observed with an electron microscope, the inside of the porous membrane was almost homogeneous, and there existed micropores having a communication property with an average pore diameter of 0.5 μm over the entire area. The porosity inside the porous membrane was 76%. The content of inorganic particles in the porous membrane is 60% by weight.

Evaluation test (tape peeling test)
About each laminated body obtained in Examples 1-6, the tape peeling test was done as follows.
(i) The following tape is applied on the titanium oxide-containing porous membrane, and the adhesive part is traced with a roller.
(ii) T-type peeling is performed under conditions of 50 mm / min using a universal tensile tester [trade name “TENSILON RTA-500” manufactured by Orientec Co., Ltd.].
(iii) The presence or absence of interfacial peeling between the titanium oxide-containing porous film and the PET film with an ITO transparent conductive film is observed.
・ Tape: Film masking tape No. 603 (# 25), 24 mm width ・ Roller: φ30 mm, 200 gf load As a result, in any of the laminates obtained in Examples 1 to 6, the titanium oxide-containing porous film and the PET film with an ITO transparent conductive film were interfaced. No peeling occurred.

Claims (8)

  A porous film formed of a composition containing a polymer and titanium oxide particles is laminated on the ITO transparent conductive film of the film with the ITO transparent conductive film, and the polymer is a polyimide resin, a polyamideimide A titanium oxide-containing porous membrane laminate, which is at least one selected from the group consisting of a resin based on resin, a polyether imide based resin, a polyether sulfone based resin, and a polyamide based resin.   2. The titanium oxide-containing porous membrane laminate according to claim 1, wherein the pores in the porous membrane have an average pore diameter of 0.01 to 10 μm and a porosity of 30 to 85%.   3. The titanium oxide-containing porous membrane laminate according to claim 1, wherein an average particle size of primary particles of the titanium oxide particles is 0.01 to 10 μm.   The titanium oxide-containing porous membrane laminate according to any one of claims 1 to 3, wherein the content of titanium oxide particles in the porous membrane is 10 to 95 wt%.   The thickness of the said porous film is 5-200 micrometers, The titanium oxide containing porous film laminated body of any one of Claims 1-4.   The titanium oxide containing porous film laminated body of any one of Claims 1-5 in which the film base material in the said film with an ITO transparent conductive film contains a polyethylene terephthalate film. It is a method of manufacturing the titanium oxide containing porous membrane laminated body of any one of Claims 1-6 , Comprising: For porous membrane formation containing the polymer which should comprise a porous membrane, and a titanium oxide particle Titanium oxide-containing porous material comprising at least a step of casting a material dispersion on the ITO transparent conductive film of the ITO transparent conductive film in the form of a film, then immersing it in a coagulating liquid, and then subjecting it to drying Manufacturing method of film | membrane laminated body. The porous film-forming material dispersion is cast in the form of a film onto the ITO transparent conductive film of the ITO transparent conductive film-attached film, and then 0 in an atmosphere with a relative humidity of 70 to 100% and a temperature of 15 to 100 ° C. The method for producing a titanium oxide-containing porous membrane laminate according to claim 7 , wherein the titanium oxide-containing porous membrane laminate is held for 2 minutes or more and then immersed in a coagulation liquid.