JP2016151748A - Photosensitive conductive film, method for forming conductive pattern using the same, conductive pattern substrate, and touch panel sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive conductive film that shows improved adhesiveness to an untreated PET which is not subjected to a surface treatment for improving adhesiveness, upon forming a transparent conductive pattern using the photosensitive conductive film, and a method for forming a conductive pattern, a conductive panel substrate and a touch panel sensor using the above photosensitive conductive film.SOLUTION: A photosensitive conductive film 10 includes a support film 1, a conductive film 2 disposed on the support film 1, and a photosensitive resin layer 3 disposed on the conductive film 2. The photosensitive resin layer 3 comprises (a) a binder polymer, (b) a photopolymerizable compound, (c) a photopolymerizable initiator, and (d) a phosphate compound, in which a ratio of (a) to (b) is from 63:37 to 50:50 with respect to total 100 parts by mass of the component (a) and the component (b).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a photosensitive conductive film, a method for forming a conductive pattern using the same, a conductive pattern substrate provided with a conductive pattern obtained by the method for forming a conductive pattern, and a touch panel sensor including the conductive pattern substrate. More specifically, it is obtained by a method for forming a conductive pattern used as an electrode wiring of a device such as a flat panel display such as a liquid crystal display element, a touch screen, or a solar cell, a photosensitive conductive film used therefor, and a method for forming a conductive pattern. The present invention relates to a conductive pattern substrate and a touch panel sensor.

  Liquid crystal display elements and touch screens are used in large electronic devices such as personal computers and televisions, small electronic devices such as car navigation systems, mobile phones and electronic dictionaries, and display devices such as OA / FA devices. In these liquid crystal display elements, touch screens, solar cells, and other devices, a transparent conductive film is used as part of transparent wiring, pixel electrodes, or terminals.

  As a material for the transparent conductive film, ITO (Indium-Tin-Oxide), indium oxide, tin oxide, or the like has been conventionally used since it exhibits high transmittance for visible light. In an electrode such as a substrate for a liquid crystal display element, a pattern obtained by patterning a transparent conductive film made of the above-described material has become mainstream.

  As a method for patterning a transparent conductive film, a method is generally used in which after forming a transparent conductive film, a resist pattern is formed by photolithography, and a predetermined portion of the conductive film is removed by wet etching to form a conductive pattern. In the case of ITO and an indium oxide film, a mixed liquid composed of two liquids of hydrochloric acid and ferric chloride is generally used as the etching liquid.

  The ITO film and the tin oxide film are generally formed by sputtering. However, in this method, the properties of the transparent conductive film are likely to change depending on the difference in sputtering method, sputtering power, gas pressure, substrate temperature, type of atmospheric gas, and the like. Differences in the film quality of the transparent conductive film due to fluctuations in sputtering conditions cause variations in the etching rate when the transparent conductive film is wet-etched, and are liable to reduce product yield due to patterning defects. In addition, since the conductive pattern forming method has undergone a sputtering process, a resist forming process, and an etching process, the process is long and has a large cost.

In recent years, attempts have been made to form a transparent conductive pattern using a material in place of ITO, indium oxide, tin oxide, or the like in order to solve the above problems.
For example, in Patent Document 1 below, after forming a conductive layer containing metal fibers such as silver fibers on a substrate, a photosensitive resin layer is formed on the conductive layer, and then exposed through a pattern mask. A method of forming a conductive pattern to be developed is disclosed.

  However, in the method described in Patent Document 1, it has been found by the inventor's examination that it is difficult to reduce the surface resistivity of the conductive pattern while ensuring the adhesion between the substrate and the conductive pattern. doing. Moreover, when using the said conductive pattern as wiring, a pixel electrode, or a terminal, the process of removing the photosensitive resin layer is required and there exists a problem that the process of forming a conductive pattern becomes complicated.

  In view of the above problem, Patent Document 2 below includes a support film, a conductive layer containing metal fibers provided on the support film, and a photosensitive resin layer provided on the conductive layer. A method of forming a conductive pattern is disclosed in which a photosensitive conductive film is laminated on a substrate so that the photosensitive resin layer is in close contact, and this is exposed and developed. This method makes it possible to form a conductive pattern with a sufficient resolution with a sufficient surface and a low surface resistivity with a simple process.

US Patent Publication No. 2007/0074316 International Publication No. 2010/021224

  By the way, when using the photosensitive conductive film of the said patent document at the time of manufacture of the transparent electrode of a touchscreen sensor, it is a conductive pattern with a photosensitive conductive film on the film (for example, untreated PET) which is not surface-treated as a board | substrate. To form a module. However, the photosensitive conductive film described in the above patent document has a problem of low adhesion when the substrate is a film that has not been surface-treated.

  More specifically, when a conductive pattern is formed using a photosensitive conductive film described in the above-mentioned patent document on a film that has not been subjected to surface treatment, the photosensitive conductive film is laminated and developed after exposure. Therefore, there was a problem that the conductive pattern was not peeled off and the conductive pattern could not be formed.

  The present invention has been made in view of the above-described problems of the prior art, and in forming a transparent conductive pattern using a photosensitive conductive film, the photosensitivity to a film that has not been subjected to surface treatment such as untreated PET. It aims at improving the adhesiveness of a conductive film.

In order to solve the above-mentioned problems, the present invention is [1] a photosensitive conductive film comprising a support film, a conductive film provided on the support film, and a photosensitive resin layer provided on the conductive film. The photosensitive resin layer contains (a) a binder polymer, (b) a photopolymerizable compound, (c) a photopolymerizable initiator, and (d) a phosphate ester compound. ) The photosensitive conductive film whose ratio of (a) and (b) is (a) :( b) = 63: 37-50: 50 with respect to a total of 100 mass parts of a component is provided.
Moreover, this invention contains 0.5 mass part or less of [2] the said (d) phosphate ester compound with respect to a total of 100 mass parts of the said (a) component and (b) component. A photosensitive conductive film is provided.
Moreover, this invention provides the photosensitive conductive film as described in said [1] or [2] which further contains [3] (e) silane coupling agents.
Moreover, the present invention provides [4] the above [1] to [1], wherein the light transmittance in a wavelength region of 450 to 650 nm is 80% or more when the total thickness of the conductive film and the photosensitive resin layer is 1 to 10 μm. A photosensitive conductive film according to any one of [3] is provided.
The present invention also provides [5] the photosensitive conductive film according to any one of [1] to [4], wherein the conductive film contains at least one conductive fiber.
The present invention also provides [6] the photosensitive conductive film according to the above [5], wherein the conductive fibers are silver fibers.
The present invention also provides [7] Laminating the photosensitive conductive film according to any one of [1] to [6] so that the photosensitive resin layer of the photosensitive conductive film is in close contact with the substrate. An exposure step of irradiating a predetermined portion of the photosensitive resin layer on the substrate with an actinic ray, and peeling the support film of the photosensitive conductive film, and then exposing the exposed photosensitive resin layer and the conductive film And a developing process for forming a conductive pattern by developing an exposed portion.
The present invention also provides [8] Laminating the photosensitive conductive film according to any one of [1] to [6] so that the photosensitive resin layer of the photosensitive conductive film is in close contact with the substrate. And a first exposure step of irradiating a predetermined portion of the photosensitive resin layer on the substrate with an actinic ray; after peeling the support film of the photosensitive conductive film, in the presence of oxygen, the first A conductive pattern is developed by developing the photosensitive resin layer and the conductive film after the second exposure process in which a part or all of the unexposed part in the exposure process is irradiated with actinic rays and the second exposure process. And a developing step for forming the conductive pattern.
Moreover, this invention provides the formation method of the conductive pattern as described in said [7] or [8] whose said board | substrate is a film which is not surface-treated [9].
The present invention also provides [10] a predetermined portion of a conductive film including a photosensitive resin layer provided on a substrate and a conductive fiber provided on a surface of the photosensitive resin layer opposite to the substrate. A conductive pattern forming method comprising: an exposure step of irradiating actinic rays to the photosensitive layer; and a developing step of forming a conductive pattern by removing an unexposed portion of the photosensitive resin layer and the conductive film, The functional resin layer contains (a) a binder polymer, (b) a photopolymerizable compound, (c) a photopolymerizable initiator, and (d) a phosphate ester compound, and is a total of component (a) and component (b). Provided is a method for forming a conductive pattern, wherein the ratio of (a) and (b) is 63:37 to 50:50 with respect to 100 parts by mass.
The present invention also provides [11] a predetermined portion of a conductive film including a photosensitive resin layer provided on a substrate and a conductive fiber provided on a surface of the photosensitive resin layer opposite to the substrate. An exposure step of irradiating with actinic rays;
In the presence of oxygen, a second exposure step in which a part or all of the unexposed portion in the first exposure step is irradiated with actinic rays, and after the second exposure step, the photosensitive resin layer and the conductive layer are electrically conductive. And a development step of forming a conductive pattern by developing a film, wherein the photosensitive resin layer comprises: (a) a binder polymer, (b) a photopolymerizable compound, (c) light. It contains a polymerizable initiator, (d) a phosphate ester compound, and the ratio of (a) and (b) is 63:37 to 50:50 with respect to 100 parts by mass of the total of (a) component and (b) component. A method for forming a conductive pattern is provided.
Moreover, this invention provides a conductive pattern board | substrate provided with the conductive pattern obtained by the formation method of the conductive pattern as described in any one of said [8]-[11] on a [12] board | substrate.
Moreover, this invention provides a touch panel sensor provided with the conductive pattern board | substrate of [13] said [12] description.

  According to the present invention, in the photosensitive conductive film, the phosphate resin compound is contained in the photosensitive resin layer, and the ratio of the binder polymer to the photopolymerizable compound is further adjusted, whereby untreated PET (generally PET is easily bonded). It is possible to improve the adhesiveness of the conductive pattern to a film that has not been subjected to a surface treatment, such as those that have been treated but not.

It is a schematic cross section showing one embodiment of a photosensitive conductive film. It is a partially cutaway perspective view showing one embodiment of a photosensitive conductive film. It is a schematic cross section for demonstrating one Embodiment of the formation method of the conductive pattern of this invention. It is a schematic cross section for demonstrating another embodiment of the formation method of the conductive pattern of this invention. It is a model top view which shows an example of an electrostatic capacitance type touch panel sensor. It is a schematic diagram for demonstrating an example of the manufacturing method of the touchscreen sensor shown by FIG. FIG. 6 is a partial cross-sectional view taken along line a-a ′ shown in FIG. 5. FIG. 6 is a partial cross-sectional view taken along line b-b ′ shown in FIG. 5.

<Photosensitive conductive film>
FIG. 1 is a schematic cross-sectional view showing an embodiment of the photosensitive conductive film of the present invention. FIG. 2 is a partially cutaway perspective view of the embodiment.
The photosensitive conductive film 10 includes a support film 1, a conductive film 2 containing conductive fibers provided on the support film 1, and a photosensitive resin layer 3 provided on the conductive film 2. The conductive film 2 and the photosensitive resin layer 3 are collectively referred to as a photosensitive layer 4.
Hereinafter, each of the support film 1 constituting the photosensitive conductive film 10, the conductive film 2 containing conductive fibers, and the photosensitive resin layer 3 will be described in detail.

  Examples of the support film 1 include polymer films having heat resistance and solvent resistance such as polyethylene terephthalate film, polyethylene film, polypropylene film, and polycarbonate film. Among these, a polyethylene terephthalate film is preferable from the viewpoint of transparency and heat resistance. These polymer films may be subjected to surface treatment within a range that can be removed from the photosensitive resin layer later.

  The haze value of the support film 1 is preferably 0.01 to 5.0%, more preferably 0.01 to 3.0%, from the viewpoint of improving sensitivity and resolution. More preferably, it is -2.0%, and it is especially preferable that it is 0.01-1.1%. In addition, a haze value can be measured based on JISK7105, for example, can be measured with commercially available turbidimeters, such as NDH-5000 (made by Nippon Denshoku Industries Co., Ltd., brand name).

  The conductive film 2 is a conductive film, and preferably contains conductive fibers. Examples of the conductive fiber include metal fibers such as gold, silver and platinum, and carbon fibers such as carbon nanotubes. These can be used alone or in combination of two or more. In the present invention, it is preferable to use metal fibers as the conductive fibers, and silver fibers are particularly preferable.

The metal fiber can be prepared, for example, by a method of reducing metal ions with a reducing agent such as NaBH ₄ or a polyol method. Commercially available products such as Unipym's Hipco single-walled carbon nanotubes can be used as the carbon nanotubes.

  The fiber diameter of the metal fiber is preferably 1 to 50 nm, more preferably 2 to 20 nm, and further preferably 3 to 10 nm. Moreover, it is preferable that the fiber length of a metal fiber is 1-100 micrometers, It is more preferable that it is 2-50 micrometers, It is further more preferable that it is 3-40 micrometers, It is especially preferable that it is 5-35 micrometers. The fiber diameter and fiber length can be measured with a scanning electron microscope.

  The thickness of the conductive film 2 varies depending on the conductive film to be formed, the use of the conductive pattern and the required conductivity, but is preferably 1 μm or less, more preferably 1 nm to 0.5 μm, and more preferably 5 nm to 0 nm. More preferably, it is 1 μm. When the thickness of the conductive film 2 is 1 μm or less, the light transmittance in the wavelength region of 450 to 650 nm is high, the pattern forming property is excellent, and it is particularly suitable for the production of a transparent electrode.

  The conductive film 2 preferably has a network structure in which metal fibers are in contact with each other. The conductive film 2 having such a network structure may be formed on the surface of the photosensitive resin layer 3 on the support film side, but conductivity is obtained in the surface direction on the surface exposed when the support film is peeled off. If it is, it may be formed in a form included in the surface layer of the photosensitive resin layer 3 on the support film 1 side. In addition, the thickness of the electrically conductive film 2 which has a network structure points out the value measured by a scanning electron micrograph.

  The conductive film 2 containing metal fibers is coated on the support film 1 with a metal fiber dispersion obtained by adding the above-described metal fibers to a dispersion stabilizer such as water or an organic solvent or a surfactant, and then dried. Can be formed. After drying, the conductive film 2 formed on the support film 1 may be laminated as necessary.

  Coating can be performed by a known method such as a roll coating method, a comma coating method, a gravure coating method, an air knife coating method, a die coating method, a bar coating method, or a spray coating method, but the film thickness distribution is good. In view of the fact that there is little foreign matter mixed into the coating liquid in a closed system, the die coating method is preferred.

From the viewpoint of reducing the resistance or haze of the conductive film 2, it is preferable to volatilize the solvent at 20 ° C. or higher and 65 ° C. or lower in order to form a uniform film in the drying step. In particular, when the metal fiber is a silver fiber, it is possible to significantly reduce resistance or haze. The drying temperature is preferably 65 ° C. or lower from the viewpoint of preventing convection from forming and forming a Benard cell and becoming difficult to form a low-resistance conductive film. Moreover, it is preferable that it is 20 degreeC or more from a viewpoint which prevents a solvent volatilizing and it takes time and becomes a problem on a process. The drying temperature is more preferably 25 ° C. or more and 65 ° C. or less, further preferably 35 ° C. or more and 65 ° C. or less, and particularly preferably 40 to 60 ° C.
In the conductive film 2, the metal fiber may coexist with a surfactant or a dispersion stabilizer.

  The photosensitive resin layer 3 is formed from a photosensitive resin composition containing (a) a binder polymer, (b) a photopolymerizable compound, (c) a photopolymerization initiator, and (d) a phosphate ester compound.

((A) binder polymer)
The binder polymer of component (a) is obtained by reaction of acrylic resin, styrene resin, epoxy resin, amide resin, amide epoxy resin, alkyd resin, phenol resin, ester resin, urethane resin, epoxy resin and (meth) acrylic acid. Known resins such as epoxy (meth) acrylate resins, acid-modified epoxy acrylate resins obtained by reaction of epoxy acrylate resins and acid anhydrides can be used without particular limitation, but preferably have a carboxyl group in the resin. .

  The acid value of component (a) is preferably 75 to 200 mgKOH / g, more preferably 75 to 150 mgKOH / g, and 75 to 120 mgKOH / g from the viewpoint of excellent patternability. More preferably, it is especially preferable that it is 77-120 mgKOH / g.

  The binder polymer of component (a) is preferably an acrylic resin from the viewpoint of excellent alkali developability and film formability, and the acrylic resin is (meth) acrylic acid and (meth) acrylic acid alkyl ester, (meth). It is more preferable to have a monomer unit derived from benzyl acrylate ester or glycidyl (meth) acrylate as a constituent unit. Here, “acrylic resin” means a polymer mainly having monomer units derived from a polymerizable monomer having a (meth) acrylic group. Moreover, (meth) acryl, such as (meth) acrylic acid and a (meth) acryl group, means acryl or methacryl.

  (A) The ratio of the carboxyl group of the binder polymer is 10 to 50% by mass as the ratio of the polymerizable monomer having a carboxyl group to the total polymerizable monomer used to obtain the binder polymer. It is preferably 12 to 40% by mass, more preferably 15 to 30% by mass, and particularly preferably 15 to 25% by mass. In terms of excellent alkali developability, the content is preferably 10% by mass or more, and in terms of excellent alkali resistance, it is preferably 50% by mass or less.

  (A) The weight average molecular weight of the binder polymer is preferably 5,000 to 300,000, more preferably 20,000 to 150,000, from the viewpoint of balancing mechanical strength and alkali developability. 30,000 to 100,000 is more preferable. In terms of excellent developer resistance, the weight average molecular weight is preferably 5,000 or more. Further, from the viewpoint of development time, it is preferably 300,000 or less. In addition, a weight average molecular weight is based on standard polystyrene conversion by GPC measurement.

((B) Photopolymerizable compound)
As the component (b), conventionally known compounds can be used without any particular limitation, but (meth) acrylate compounds having a skeleton derived from pentaerythritol, (meth) acrylate compounds having a skeleton derived from dipentaerythritol, and tetramethylolpropane. It is preferable to include at least one selected from a (meth) acrylate compound having a skeleton derived from and a (meth) acrylate compound having a skeleton derived from trimethylolpropane, and a (meth) acrylate compound having a skeleton derived from dipentaerythritol And at least one selected from (meth) acrylate compounds having a skeleton derived from trimethylolpropane. These are trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethoxytri (meth) acrylate, trimethylolpropane diethoxytri (meth) acrylate, trimethylolpropane triethoxytri (meth) ) Acrylate, trimethylolpropane tetraethoxytri (meth) acrylate, trimethylolpropane pentaethoxytri (meth) acrylate, pentaerythritol triacrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tetramethylol Examples include methane tri (meth) acrylate and tetramethylolmethane tetra (meth) acrylate.
As these compounds, those commercially available can be used (for example, TMPTA: manufactured by Nippon Kayaku Co., Ltd.).

  (B) The content rate of a component is 37-50 mass% with respect to a total of 100 mass% of (a) binder polymer and (b) photopolymerizable compound, and it is preferable that it is 40-50 mass%. In terms of excellent photocurability and coating properties of the transferred conductive film (conductive film and photosensitive resin layer), it is preferably 37% by mass or more, and in terms of excellent storage stability when wound as a film. 50 mass% or less is preferable.

((C) Photopolymerizable initiator)
The photopolymerization initiator of the component (c) is not particularly limited as long as the light wavelength of the exposure machine to be used matches the wavelength necessary for function expression, but from the viewpoint of increasing the transparency of the cured film. It is preferable that an oxime ester compound or a phosphine oxide compound is included.
Specifically, as the oxime ester compound, 1,2-octanedione, 1- [4- (phenylthio) -phenyl, 2- (O-benzoyloxime)], or ethanone, 1- [9-ethyl-6- (2-Methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime) is preferred. These are commercially available as IRGACURE OXE 01 and IRGACURE OXE 02 (both manufactured by BASF Corporation, respectively).

As the phosphine oxide compound, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide is preferable.
Among these, from the viewpoint of color and sensitivity, it is particularly preferable to use LUCIRIN TPO: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (trade name, manufactured by BASF).

  The content ratio of the photopolymerizable initiator of the component (c) is preferably 0.1 to 20 parts by mass with respect to 100 parts by mass in total of the (a) binder polymer and (b) the photopolymerizable compound, It is more preferably 1 to 10 parts by mass, and further preferably 1 to 5 parts by mass. In terms of excellent photosensitivity, it is preferably 0.1 parts by mass or more, and in terms of excellent photocurability, it is preferably 20 parts by mass or less.

((D) Phosphate ester compound)
The phosphoric acid ester compound as the component (d) is not particularly limited as long as it is a compound having a hydroxyl group at the phosphorus atom, but compounds represented by the following formulas (1) to (3) are more preferably used. Examples include the Phosmer series, Phosmer-M, Phosmer-CL, Phosmer-PE, Phosmer-MH, and Phosmer-PP manufactured by Unichemical. Moreover, the KAYAMER series by Nippon Kayaku Co., Ltd. is mentioned, Among these, KAYAMER PM21 (the following general formula (3)) or PM-2 (the following general formula (1)) by Nippon Kayaku Co., Ltd. is preferable. .

  It is preferable that the content rate of (d) component is 0.5 mass part or less with respect to a total of 100 mass parts of (a) binder polymer and (b) photopolymerizable compound. The amount is more preferably 0.4 parts by mass or less, and further preferably 0.3 parts or less. If it is 0.5 parts by mass or less, the linear resistance increase rate at constant temperature and humidity is 20% or less, and the connection stability is maintained.

  In the present invention, it is possible to suppress the corrosion of the base material by the phosphate ester compound of component (d), and (a) the adhesiveness is improved by increasing the ratio of (b) the photopolymerizable compound to the binder polymer. It is presumed that the adhesion to a film not subjected to surface treatment such as treated PET has been improved.

((E) Silane coupling agent)
A silane coupling agent is an organosilicon compound (Y—Si (CH ₃ ) having both an organic functional group “Y” that can be expected to react and interact with an organic substance in one molecule and a hydrolyzable group “OR”. ) _N (OR) _3-n , where n is an integer of 0 to 3), and the organic polymer or the like is hydrolyzed and reacted with the organic polymer or the like via the organic functional group “Y”, thereby reacting with the inorganic surface or the like. It forms a bond and works to firmly connect the two with different chemical properties. Examples of the organic functional group “Y” include amino group, epoxy group, (meth) acryl group, vinyl group, mercapto group, etc., and hydrolyzable group “OR” includes methoxy group (—OCH ₃ ), ethoxy group ( -OC ₂ H _5), and the like acetyloxy group (-OCOCH ₃₎ is.
As the silane coupling agent of component (e), OFS-6030 γ-methacryloyloxypropyltrimethoxy silane (manufactured by Toray Dow Corning Co., Ltd.) having a (meth) acryl group is preferable. As for the content rate of (e) component, 0-10 mass parts is preferable with respect to a total of 100 mass parts of (a) binder polymer and (b) photopolymerizable compound. More preferably 4 parts by mass or more. 6-10 mass parts is further more preferable, and it is especially preferable that it is 8-10 mass parts.

  In the photosensitive resin layer (photosensitive resin composition) used in the present invention, in addition to the components (a) to (e) described above, a plasticizer such as p-toluenesulfonamide and a filler, if necessary. Additives such as an antifoaming agent, a flame retardant, a stabilizer, a leveling agent, a peeling accelerator, an antioxidant, a fragrance, an imaging agent, and a thermal crosslinking agent may be blended. These additives can be contained alone or in combination of two or more. It is preferable that the addition amount of these additives is 0.01-20 mass parts with respect to 100 mass parts in total of (a) binder polymer and (b) photopolymerizable compound, respectively.

The photosensitive resin layer 3 can be formed by applying and drying a solution of the photosensitive resin composition containing the components (a) to (d) described above, preferably including the components (a) to (e).
As the solvent, methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether and the like can be used.
The solid content in the solution is preferably about 10 to 60% by mass.

The solution of the photosensitive resin composition is applied onto the conductive film 2 formed on the support film 1 and dried. However, in this case, the amount of the remaining organic solvent in the photosensitive resin layer after drying is preferably 2% by mass or less in order to prevent the organic solvent from diffusing in the subsequent step.
The coating can be performed by a known method such as a roll coating method, a comma coating method, a gravure coating method, an air knife coating method, a die coating method, a bar coating method, or a spray coating method. After coating, drying for removing the organic solvent and the like can be performed at 70 to 150 ° C. for about 5 to 30 minutes with a hot air convection dryer or the like.

  Although the thickness of the photosensitive resin layer 3 changes with uses, it is preferable that it is 0.5-50 micrometers by the thickness after drying, It is more preferable that it is 0.5-30 micrometers, It is 0.5-15 micrometers. Is more preferable, and 0.5 to 10 μm is particularly preferable. If the thickness is less than 0.5 μm, the coating tends to be difficult. If the thickness exceeds 50 μm, the sensitivity due to the decrease in light transmission is insufficient, and the photocurability of the photosensitive resin layer to be transferred tends to decrease.

  In the photosensitive conductive film of the present embodiment, the laminate of the conductive film 2 and the photosensitive resin layer 3 has a light transmittance of 80% in a wavelength region of 450 to 650 nm when the total thickness of both layers is 1 to 10 μm. It is preferable that it is above, and it is more preferable that it is 85% or more. When the conductive film and the photosensitive resin layer satisfy such conditions, visibility on a display panel or the like is improved.

In the photosensitive conductive film of the present invention, a protective film can be laminated so as to be in contact with the surface of the photosensitive resin layer 3 opposite to the support film 1 side.
As the protective film, a polymer film having heat resistance and solvent resistance such as a polyethylene terephthalate film, a polypropylene film, and a polyethylene film can be used. Moreover, you may use the polymer film similar to the above-mentioned support film as a protective film.

  The adhesive force between the protective film and the photosensitive resin layer is greater than the adhesive force between the conductive film 2 and the photosensitive resin layer 3 and the support film 1 in order to facilitate the peeling of the protective film from the photosensitive resin layer. Is preferably small.

<Method for forming conductive pattern>
The conductive pattern forming method of the present invention includes a step of laminating a photosensitive conductive film so that the photosensitive resin layer of the photosensitive conductive film is in close contact with the substrate, a conductive resin layer provided on the substrate, and a conductive layer. An exposure step of irradiating the film with actinic rays in a pattern and a development step of forming a conductive pattern by removing the photosensitive resin layer and the unexposed portion of the conductive film are included.
The photosensitive resin layer contains (a) a binder polymer, (b) a photopolymerizable compound, (c) a photopolymerizable initiator, and (d) a phosphate ester compound.
The conductive film (conductive layer) is a film provided on the surface opposite to the substrate of the photosensitive resin layer, and includes conductive fibers.

An embodiment of the method for forming a conductive pattern of the present invention will be described with reference to FIG.
For the formation of the conductive pattern, a laminate shown in FIG. 3A can be used. In the laminate of FIG. 3A, a photosensitive conductive film 10 having a photosensitive resin layer 3 and a conductive film 2 including a conductive film 2 and a support film 1 is provided on a substrate 20.
In addition, this laminated body can be obtained by laminating | stacking the photosensitive conductive film 10 of this invention mentioned above on the board | substrate 20 so that the photosensitive resin layer 3 may contact | connect the board | substrate 20, for example.

  First, the mask 5 is provided on the photosensitive conductive film 10, and the photosensitive layer 4 (the conductive film 2 and the photosensitive resin layer 3) is irradiated with the active light L in a pattern through the mask 5 (exposure process: FIG. 3). (B)). Then, the support film 1 is peeled off, and then an uncured portion (unexposed portion) is removed by development to form a conductive pattern (conductive film 2a) (development process: FIG. 3C).

Here, the conductive pattern obtained by the above method has the thickness of the cured resin layer 3b in addition to the thickness of the conductive film 2a. These thicknesses are steps Hb from the substrate. If the level difference Hb is large, the smoothness required for a display or the like may be difficult to obtain, and the conductive pattern may be easily visually recognized. Therefore, it may be used separately from the following method (FIG. 4) depending on the application. it can.
The method for forming the conductive pattern is preferably formed using the photosensitive conductive film of the present invention, but is not limited thereto. For example, a conductive resin layer and a conductive film containing conductive fibers are separately provided on a substrate. After the formation, it may be formed by exposure and development.

Another embodiment of the method for forming a conductive pattern of the present invention will be described with reference to FIG.
The method shown in FIG. 4 is the same as the above-described forming method until the exposure step (first exposure step: FIG. 4B) in which a predetermined portion of the photosensitive layer 4 having the support film 1 is irradiated with actinic rays.
After the first exposure step, the support film 1 is peeled off, and in the presence of oxygen, a part or all of the exposed and unexposed portions in the first exposure step are irradiated with actinic rays (second Exposure process: FIG. 4 (c)). As a result, the resin cured layer 3a in which the conductive film 2a is not formed together with the conductive pattern 2a is provided on the substrate 20, so that the conductive property is reduced as compared with the case of FIG. 3C in which only the conductive pattern is provided on the substrate. The step of the pattern can be reduced (step Ha shown in FIG. 4D).

  The substrate used in the method for forming the conductive pattern is glass, semiconductor, metal oxide insulator, ceramics, plastic, printed circuit board, etc., but in the present invention, in particular, a plastic substrate, particularly a plastic film not subjected to surface treatment (here Is also suitable for plastic sheets). As the plastic film, a PET film excellent in characteristics and cost is suitable. For the PET film or the like, an easy-adhesive film in which adhesion is improved by performing surface treatment such as primer coating, corona treatment, and plasma treatment to improve adhesion is commercially available. This treatment requires processing costs and tends to sacrifice some characteristics such as transparency, but in the present invention, a film that has not been surface-treated can be used as a substrate.

<Touch panel sensor>
A touch panel sensor according to the present invention includes the conductive pattern substrate.
FIG. 5 is a schematic top view illustrating an example of a capacitive touch panel sensor. The touch panel sensor shown in FIG. 5 has a touch screen 102 for detecting a touch position on one surface of a transparent substrate 101, and a transparent electrode 103 that detects a change in capacitance in this region and uses it as an X position coordinate; A transparent electrode 104 having Y position coordinates is provided. Each of the transparent electrodes 103 and 104 having the X and Y position coordinates includes a lead wire 105 for connecting to a driver element circuit for controlling an electric signal as a touch panel, and the lead wire 105 and the transparent electrodes 103 and 104. A connection electrode 106 for connecting the two is disposed. Further, a connection terminal 107 connected to the driver element circuit is disposed at the end of the lead-out wiring 105 opposite to the connection electrode 106.

  FIG. 6 is a schematic view showing an example of a method for manufacturing the touch panel sensor shown in FIG. In the present embodiment, the transparent electrodes 103 and 104 are formed by the conductive pattern forming method according to the present invention. First, as shown in FIG. 6A, a transparent electrode (X position coordinate) 103 is formed on a transparent substrate 101. Specifically, the photosensitive conductive film 10 is laminated so that the photosensitive resin layer is in contact with the transparent substrate 101. The transferred photosensitive layer 4 (the conductive film 2 and the photosensitive resin layer 3) is irradiated with an actinic ray in a desired shape through a light-shielding mask (first exposure step). Thereafter, the light shielding mask is removed, the support film is further peeled off, and the photosensitive layer 4 is irradiated with actinic rays (second exposure step). By performing development after the exposure step, the conductive film 2 is removed together with the photosensitive resin layer 3 that is not sufficiently cured, and a conductive pattern 2a is formed. The transparent electrode 103 for detecting the X position coordinate is formed by the conductive pattern 2a (FIG. 6B). FIG. 6B is a schematic cross-sectional view taken along the line II of FIG. By forming the transparent electrode 103 by the method for forming a conductive pattern according to the present invention, the transparent electrode 103 with a small step can be provided.

  Subsequently, a transparent electrode (Y position coordinate) 104 is formed as shown in FIG. A new photosensitive conductive film 10 is further laminated on the substrate 101 including the transparent electrode 103 formed by the above-described process, and the transparent electrode 104 for detecting the Y position coordinate is formed by the same operation as described above (see FIG. 6 (d)). FIG.6 (d) is a schematic cross section of the II-II cut surface of FIG.6 (c). By forming the transparent electrode 104 by the conductive pattern forming method according to the present invention, even when the transparent electrode 104 is formed on the transparent electrode 103, reduction in aesthetics due to stepping or entrainment of bubbles is sufficiently suppressed. A touch panel sensor with high smoothness can be created.

  Next, on the surface of the transparent substrate 101, a lead wiring 105 for connecting to an external circuit and a connection electrode 106 for connecting the lead wiring and the transparent electrodes 103 and 104 are formed. In FIG. 6, the lead-out wiring 105 and the connection electrode 106 are shown to be formed after the formation of the transparent electrodes 103 and 104, but they may be formed at the same time as each transparent electrode is formed. The lead-out wiring 105 can be formed at the same time as the connection electrode 106 is formed by screen printing using a conductive paste material containing flaky silver, for example.

7 and 8 are partial cross-sectional views taken along the lines aa ′ and bb ′ shown in FIG. 5, respectively. These indicate the intersections of the transparent electrodes at the XY position coordinates.
As shown in FIGS. 7 and 8, the transparent electrode is formed by the conductive pattern forming method according to the present invention, so that a touch panel sensor with small steps and high smoothness can be obtained.

  Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

Production Example 1 [Preparation of silver fiber dispersion]
(1) Preparation of silver fiber by polyol method 500 ml of ethylene glycol was placed in a 2000 ml three-necked flask and heated to 160 ° C. with an oil bath while stirring with a magnetic stirrer in a nitrogen atmosphere. A solution prepared by dissolving ₂ mg of PtCl ₂ separately prepared in 50 ml of ethylene glycol was added dropwise thereto. After 4 to 5 minutes, a solution in which 5 g of AgNO ₃ was dissolved in 300 ml of ethylene glycol and a solution in which 5 g of polyvinylpyrrolidone having a weight average molecular weight of 40,000 (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 150 ml of ethylene glycol were respectively obtained. From the dropping funnel in 1 minute, and then stirred at 160 ° C. for 60 minutes.

  The reaction solution was allowed to stand at 30 ° C. or lower, diluted 10-fold with acetone, centrifuged at 2000 rpm for 20 minutes with a centrifuge, and the supernatant was decanted. Acetone was added to the precipitate, and after stirring, the mixture was centrifuged under the same conditions as described above, and acetone was decanted. Then, it centrifuged twice similarly using distilled water, and obtained the silver fiber. When the obtained silver fiber was observed with an optical microscope, the fiber diameter (diameter) was 30 nm, and the fiber length was 30 μm.

(2) Preparation of Silver Fiber Dispersion Solution Disperse in pure water so that the silver fiber obtained in (1) above has a concentration of 0.2% by mass and dodecyl-pentaethylene glycol at a concentration of 0.1% by mass. As a result, a silver fiber dispersion 1 was obtained.

Production Example 2 [Preparation of Photosensitive Resin Composition Solution]
The materials shown in Table 1 were blended in the blending amounts (unit: parts by mass) shown in the same table to prepare a solution of the photosensitive resin composition.

Each component in Table 1 is shown below. Acrylic resin A: copolymer of methacrylic acid / methyl methacrylate / ethyl acrylate = 12/58/30 (molar ratio), weight average molecular weight 67,000
TMPTA: Trimethylolpropane triacrylate (made by Shin-Nakamura Chemical Co., Ltd., trade name)
LUCIRIN TPO: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (trade name, manufactured by BASF)
PM21: Phosphate ester compound containing a photopolymerizable unsaturated bond (manufactured by Nippon Kayaku Co., Ltd., trade name KAYAMER PM21)
OFS-6030: γ-methacryloyloxypropyltrimethoxy silane (manufactured by Dow Corning Toray)
Additive 8030: Octamethylcyclotetrasiloxane (manufactured by Dow Corning Toray)
AW-500: Phenolic polymerization inhibitor (2,2′-methylene-bis (4-ethyl-6-tertbutylphenol), manufactured by Kawaguchi Chemical Industry Co., Ltd., trade name Antage W500)

Example 1
(1) Production of photosensitive conductive film On a polyethylene terephthalate film (PET film, manufactured by Toyobo Co., Ltd., trade name “A-1517”) having a thickness of 16 μm as a support film, the silver fiber dispersion 1 prepared in Production Example 1 was used. It apply | coated uniformly with the coating machine at 25 g / m < ² >, it dried at 60-90 degreeC, and it pressurized with the linear pressure of 10 kg / cm at room temperature (25 degreeC). Thereby, the electrically conductive film containing an electroconductive fiber was formed on the support film. In addition, the film thickness after drying of the electrically conductive film was about 0.01 micrometer.

  Next, after stirring the solution of the photosensitive resin composition prepared in Table 1, it was uniformly coated on a 16 μm-thick polyethylene terephthalate film on which a conductive film was formed, and was placed on a hot plate maintained at 80 ° C. for 5 minutes. It dried and formed the photosensitive resin layer. Thereafter, the photosensitive resin layer was covered with a protective film made of polyethylene (manufactured by Tamapoly Co., Ltd., trade name “NF-13”) to obtain a photosensitive conductive film. In addition, the film thickness after drying of the photosensitive resin layer was 2-3 micrometers.

(2) Formation of conductive pattern While peeling the protective film of the photosensitive conductive film obtained above on an untreated PET substrate that has not been surface-treated as a substrate, the photosensitive resin layer is opposed to the untreated PET substrate. , 110 ° C., 0.4 MPa.
After lamination, when the substrate is cooled and the temperature of the substrate reaches 23 ° C., a step tablet for measuring photosensitive characteristics (S / T; L (line) / S (space) = x / 400 μm, x = 6 to 47 μm) Using a light exposure machine (trade name “EXM-1201” manufactured by Oak Manufacturing Co., Ltd.) having a high-pressure mercury lamp lamp from the support film side, 20 mJ / cm ^{2 was} exposed under vacuum (first exposure step). . After peeling off the support film, it was irradiated with light at an exposure amount of 50 mJ / cm ^{2 in} the atmosphere (second exposure step).

Next, at 30 ° C., a 1% by mass aqueous sodium carbonate solution, a 0.3% by mass surfactant (Nonal 912A, polyoxyethylene cumylphenyl ether, manufactured by Toho Chemical Co., Ltd.), a 0.3% by mass antifoaming agent ( Development was carried out by spraying Antix # 100, modified silicone (manufactured by Maruzen Pharmaceutical Co., Ltd.) for 40 seconds. Further, an exposure dose of 1 J / cm ² was irradiated with a UV exposure machine.
With the above operation, the conductive pattern shown in FIG. 4D was formed on the untreated PET substrate.
As the evaluation of adhesion, the resin peeling at the time of peeling the support film, the pattern defect after development, and the appearance (surface state) were visually confirmed.
The pattern defect after development was evaluated by visually observing the conductive pattern after development, and “X” when the pattern remained completely, and “X” when the conductive pattern caused development flow.
The resin peeling at the time of peeling the support film is an evaluation of adhesion, and compares the adhesive strength A between the substrate and the photosensitive resin layer and the adhesive strength B between the support film and the photosensitive layer (conductive film and photosensitive resin layer). When the support film is peeled off, the case where it is peeled between the support film and the photosensitive layer (adhesive force A> adhesive force B) is evaluated as “◯” because the photosensitive resin does not peel from the substrate, and the substrate and the photosensitive resin layer The case where it peeled between was evaluated as "x".
Appearance was observed when the conductive pattern was formed. If the surface was not rough, it was rated as “O”. If the surface was rough, the surface was rough. Things were evaluated as “x”.
The results are shown in Table 2.

(Example 2, Comparative Examples 1-5)
A photosensitive conductive film was produced in the same manner as in Example 1 except that the composition of the photosensitive resin composition solution was as shown in Table 2, and a conductive pattern was formed. The results are shown in Table 2.

＊配合量の単位は質量部である。

* The unit of blending amount is parts by mass.

  Using untreated PET film that has not been surface-treated, the solid content ratio of (a) and (b) with respect to a total of 100 parts by mass of the binder polymer of component (a) and the photopolymerizable compound of component (b) (A) :( b) = 63: 37 to 50:50, Comparative Examples 2 to 3 show that the photosensitive resin layer is peeled off from the substrate when the support film is peeled off (adhesion is poor), or the pattern after development Defects are produced and the appearance is deteriorated. On the other hand, Examples 1 and 2 in the said range are excellent in all of them. Moreover, even if it was in the said range, the comparative example 1 which does not contain (d) component was inferior to an external appearance, and the surface was seen rough. When the ratio of (a) :( b) deviates as in Comparative Examples 2 to 5, even if the component (d) was blended in an amount of 0 to 1.0 part by mass, no improvement in the evaluation items was observed. The combination of the ratio (a) :( b) and the component (d) improves the evaluation items.

(Example 3)
A photosensitive conductive film having the same composition as in Example 1 was produced. The substrate is easy-adhesion-treated PET (Cosmo Shine A4300, double-sided easy-adhesion treatment, manufactured by Toyobo Co., Ltd.), the exposure amount after peeling the support film is 200 mJ / cm ² , and the mask used is changed to Example 1. Similarly, a conductive pattern was formed. A mask with Line / Space = 1 mm / 1 mm was used.

After the formation of the conductive pattern, a conductive silver paste was applied to the pattern end and dried at 130 ° C. for 10 minutes with an explosion-proof dryer.
An OCA tape (OPTICALLY CLEAR ADHESIVE TAPE, an adhesive tape using a highly transparent acrylic adhesive, manufactured by 3M Japan Co., Ltd.) was attached with a hand roller so as to cover the conductive pattern of the sample. At that time, the silver paste was not covered with the OCA tape for ensuring conduction.

After measuring the wire resistance value of the sample with a commercially available tester, the sample was left in a constant temperature and humidity chamber of temperature / humidity = 85 ° C./85% RH, and the wire resistance value was measured over time.
The measurement results are shown in Table 3.

  From the above results, in the photosensitive conductive film of the present invention, by adding a phosphate ester compound to the resin layer of the photosensitive conductive film and adjusting the ratio of the binder polymer to the photopolymerizable compound, It was confirmed that the adhesion to the treated PET substrate can be improved. Furthermore, the resistance value increase after being allowed to stand for 1000 hours under constant temperature and humidity could be kept at 20% or less.

  At present, in touch panel sensors, flexible substrates such as untreated PET are spreading as the substrate to which the photosensitive conductive film is closely attached, and in these structures, it is essential to improve the adhesion of the photosensitive conductive film to the untreated PET. . By this invention, the adhesiveness with respect to untreated PET of a photosensitive conductive film can improve, and it can suppress that a photosensitive conductive film peels from untreated PET. In addition, electrical characteristics over time can be maintained. Thereby, it is possible to reliably manufacture a touch panel sensor of photosensitive conductive film / untreated PET.

The photosensitive conductive film and conductive pattern of the present invention can be used for the formation of conductive patterns used as electrode wirings for devices such as flat panel displays such as liquid crystal display elements, touch screens, and solar cells.
The touch panel sensor of the present invention can be used for a liquid crystal display element and a touch screen.

1 support film 2 conductive film 2a conductive film (conductive pattern)
3 photosensitive resin layer 3a, 3b cured resin layer 4 photosensitive layer 5 mask (mask pattern)
10 Photosensitive conductive film 20 Substrate 101 Transparent substrate 102 Touch screen 103 Transparent electrode (X position coordinate)
104 Transparent electrode (Y position coordinate)
105 Lead-out wiring 106 Connection electrode 107 Connection terminal

Claims (13)

A photosensitive conductive film comprising a support film, a conductive film provided on the support film, and a photosensitive resin layer provided on the conductive film, the photosensitive resin layer comprising:
(A) a binder polymer,
(B) a photopolymerizable compound,
(C) contains a photopolymerizable initiator, and (d) a phosphoric ester compound,
The photosensitive conductive film whose ratio of (a) and (b) is (a) :( b) = 63: 37-50: 50 with respect to a total of 100 mass parts of (a) component and (b) component.   The photosensitive conductive film of Claim 1 which contains the said (d) phosphate ester compound 0.5 mass part or less with respect to a total of 100 mass parts of the said (a) component and (b) component.   (E) The photosensitive conductive film of Claim 1 or Claim 2 which further contains a silane coupling agent.   The light transmittance in the wavelength range of 450-650 nm when the total thickness of the said electrically conductive film and the photosensitive resin layer shall be 1-10 micrometers is 80% or more, The photosensitive as described in any one of Claims 1-3. Conductive film.   The photosensitive conductive film as described in any one of Claims 1-4 in which the said electrically conductive film contains at least 1 type of conductive fiber.   The photosensitive conductive film according to claim 5, wherein the conductive fiber is a silver fiber. Laminating the photosensitive conductive film according to any one of claims 1 to 6 so that the photosensitive resin layer of the photosensitive conductive film is in close contact with the substrate;
An exposure step of irradiating a predetermined portion of the photosensitive resin layer on the substrate with an actinic ray;
A development step of forming a conductive pattern by developing the exposed photosensitive resin layer and an unexposed portion of the conductive film after peeling the support film of the photosensitive conductive film,
A method for forming a conductive pattern. Laminating the photosensitive conductive film according to any one of claims 1 to 6 so that the photosensitive resin layer of the photosensitive conductive film is in close contact with the substrate;
A first exposure step of irradiating a predetermined portion of the photosensitive resin layer on the substrate with an actinic ray;
After peeling the support film of the photosensitive conductive film, in the presence of oxygen, a second exposure step of irradiating a part or all of the unexposed portion in the first exposure step with actinic rays,
A developing step of forming a conductive pattern by developing the photosensitive resin layer and the conductive film after the second exposure step;
A method for forming a conductive pattern.   The method for forming a conductive pattern according to claim 7 or 8, wherein the substrate is a film that has not been surface-treated. A photosensitive resin layer provided on a substrate; and an exposure step of irradiating a predetermined portion of a conductive film including conductive fibers provided on a surface of the photosensitive resin layer opposite to the substrate with active light rays; ,
A development process of forming a conductive pattern by removing the photosensitive resin layer and an unexposed portion of the conductive film,
The photosensitive resin layer contains (a) a binder polymer, (b) a photopolymerizable compound, (c) a photopolymerizable initiator, and (d) a phosphate ester compound, and includes (a) component and (b) component. The formation method of the conductive pattern whose ratio of (a) and (b) is 63: 37-50: 50 with respect to a total of 100 mass parts. A photosensitive resin layer provided on a substrate; and an exposure step of irradiating a predetermined portion of a conductive film including conductive fibers provided on a surface of the photosensitive resin layer opposite to the substrate with active light rays; ,
In the presence of oxygen, a second exposure step in which a part or all of the unexposed portion in the first exposure step is irradiated with actinic rays, and after the second exposure step, the photosensitive resin layer and the conductive layer are electrically conductive. A conductive pattern forming method including a developing step of forming a conductive pattern by developing a film,
The photosensitive resin layer contains (a) a binder polymer, (b) a photopolymerizable compound, (c) a photopolymerizable initiator, and (d) a phosphate ester compound, and includes (a) component and (b) component. The formation method of the conductive pattern whose ratio of (a) and (b) is 63: 37-50: 50 with respect to a total of 100 mass parts.   A conductive pattern substrate comprising a conductive pattern obtained by the method for forming a conductive pattern according to any one of claims 8 to 11 on a substrate.   A touch panel sensor comprising the conductive pattern substrate according to claim 12.

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