JP6540766B2 - Protective film for touch panel electrode and touch panel - Google Patents

Description

  The present invention relates to a protective film for a touch panel electrode and a touch panel having the same.

  Liquid crystal display elements and touch panels (touch sensors) are used in display devices such as large electronic devices such as personal computers and televisions, small electronic devices such as car navigation systems, cellular phones, electronic dictionaries and OA / FA devices. The liquid crystal display element or the touch panel is provided with an electrode made of a transparent conductive electrode material. As a transparent conductive electrode material, ITO (Indium-Tin-Oxide), indium oxide and tin oxide are known, and since these materials exhibit high visible light transmittance, they can be used as electrode materials for substrates for liquid crystal display elements and the like. It is mainstream.

  Various types of touch panels have already been put to practical use, but in recent years, use of capacitive touch panels has progressed. In the capacitive touch panel, when a finger tip as a conductor comes in contact with the touch input surface, capacitive coupling occurs between the finger tip and the conductive film to form a capacitor. For this reason, the capacitive touch panel detects the coordinates by capturing a change in charge at the contact position of the fingertip.

  In particular, a projected capacitive touch panel is capable of detecting multiple points of a fingertip, so it has good operability that can perform complicated instructions, and because of its good operability, it can be used as a mobile phone or a portable type The use as an input device on a display surface of an apparatus having a small display device such as a music player is in progress.

  Generally, in a projected capacitive touch panel, a plurality of X electrodes and a plurality of Y electrodes orthogonal to the X electrodes have a two-layer structure in order to express two-dimensional coordinates by the X axis and the Y axis. ITO (Indium-Tin-Oxide) is used as the electrode.

  By the way, since the frame area of the touch panel is an area in which the touch position can not be detected, narrowing the area of the frame area is an important element for improving product value. In the frame area, metal wiring is required to transmit a detection signal of the touch position, but in order to narrow the frame area, it is necessary to narrow the width of the metal wiring. Since the conductivity of ITO is not high enough, metal wiring is generally formed of copper.

  However, in the case of the touch panel as described above, corrosion components such as water and salt may intrude into the inside from the sensing region when the finger is touched. When the corrosive component intrudes into the inside of the touch panel, the metal wiring is corroded, and there is a possibility that the electrical resistance between the electrode and the drive circuit increases, or the wire is broken.

  In order to prevent corrosion of metal wiring, a capacitive projection type touch panel in which an insulating layer is formed on metal is disclosed (for example, Patent Document 1). In this touch panel, a silicon dioxide layer is formed on metal by plasma chemical vapor deposition (plasma CVD) to prevent metal corrosion. However, since this method uses a plasma CVD method, high temperature processing is required, and there is a problem that the base material is limited and the manufacturing cost becomes high.

  By the way, as a method of providing a resist film in a required place, a method is known in which a photosensitive layer made of a photosensitive resin composition is provided on a predetermined base material, and this photosensitive layer is exposed and developed (for example, 2 to 4). Moreover, forming the protective film of a touch panel by the said method is disclosed by patent document 5 and 6. FIG.

JP, 2011-28594, A JP-A-7-253666 Unexamined-Japanese-Patent No. 2005-99647 Unexamined-Japanese-Patent No. 11-133617 gazette JP, 2010-27033, A JP, 2011-232584, A

  The production of the protective film by the photosensitive resin composition can be expected to reduce the cost as compared to the plasma CVD method. However, when the protective film is formed on the touch panel electrode, if the thickness of the resin film is large, a difference in level may be noticeable between the portion with the film and the portion without the film. Therefore, it is preferable to make the protective film as thin as possible.

  However, there has been no example in which the corrosion resistance of the film formed from the photosensitive resin composition was examined at a thickness of 10 μm or less.

  Moreover, when protection of a sensing area | region is also considered, transparency of a resin cured film is requested | required in preparation of the protective film by a photosensitive resin composition.

  The present invention provides a protective film for a touch panel electrode which has a desired shape, is excellent in transparency, and has sufficient corrosion resistance even with a thin film, and a touch panel having such a protective film. The purpose is

  As a result of intensive studies conducted by the present inventors to solve the above problems, the resin cured film formed of a specific photosensitive resin composition and having a specific compound detected by pyrolysis gas chromatography mass spectrometry has a desired shape. In addition to being excellent in transparency, it has sufficient corrosion resistance even at a thickness of 10 μm or less, and is found to be suitable as a protective film for a touch panel electrode, thus completing the present invention. The

  The present invention is a protective film for a touch panel electrode obtained by curing a predetermined portion of a photosensitive layer comprising a photosensitive resin composition containing a binder polymer, a photopolymerizable compound, and a photopolymerization initiator. Provided is a protective film of an electrode for a touch panel in which heptanonitrile and benzoic acid are detected by pyrolysis gas chromatography mass spectrometry.

  According to the protective film of the electrode for a touch panel of the present invention, it is possible to have a desired shape, to be excellent in transparency, and to have sufficient corrosion resistance even for a thin film having a thickness of 10 μm or less.

  The present inventors consider as follows the reason why the protective film of the electrode for a touch panel of the present invention can exhibit the above effect. When the thickness of the protective film is reduced, the corrosive component easily intrudes into the touch panel electrode. On the other hand, it is considered that the photosensitive layer containing a component serving as a detection source of heptanonitrile and benzoic acid has a sufficient transparency and patternability, and has a composition capable of forming a dense cured state. By forming the protective film of the electrode for a touch panel from such a photosensitive layer, it is possible to achieve both of the sufficient corrosion resistance capable of suppressing the entry of the corrosive component, the transparency and the pattern forming property, and the present invention. The people guess.

  In the protective film of the electrode for a touch panel according to the present invention, the detection peak area of benzoic acid in pyrolysis gas chromatography mass spectrometry is 1 to 10 with respect to the detection peak area of heptanonitrile, from the viewpoint of further improving the corrosion resistance. % Is preferred.

  Moreover, it is preferable that the minimum value of the visible light transmittance | permeability in 400-700 nm of the protective film of the electrode for touchscreens of this invention is 90% or more.

  Furthermore, from the viewpoint of providing a protective film having a good shape, the binder polymer preferably has a carboxyl group and an acid value of 75 mg KOH / g or more.

  Further, from the viewpoint of further improving the corrosion resistance, the binder polymer preferably has a hydroxyl value of 50 mg KOH / g or less.

  Furthermore, it is preferable that the protective film of the electrode for touchscreens of this invention is 10 micrometers or less in thickness.

  The present invention also provides a touch panel having the protective film according to the present invention.

  According to the present invention, a protective film for a touch panel electrode having a desired shape and being excellent in transparency and having sufficient corrosion resistance even with a thin film, and a touch panel having such a protective film Can be provided.

It is a schematic cross section which shows one Embodiment of the photosensitive element used in order to form the protective film of the electrode for touchscreens which concerns on this invention. It is a schematic cross section for describing one Embodiment of the formation method of the protective film of the electrode for touchscreens concerning this invention. It is a model top view which shows an example of a capacitive touch panel. It is a model top view which shows another example of a capacitive touch panel. (A) is a fragmentary sectional view along the VV line of C section shown in Drawing 3, and (b) is a fragmentary sectional view showing another mode. It is a gas chromatogram when thermal decomposition gas chromatograph mass spectrometry is performed about the protective film obtained in Example 6.

  Hereinafter, modes for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the present specification, (meth) acrylic acid means acrylic acid or methacrylic acid, (meth) acrylate means acrylate or a methacrylate corresponding thereto, and (meth) acryloyl group means acryloyl group. It means a group or a methacryloyl group. The (poly) oxyethylene chain means an oxyethylene group or a polyoxyethylene group, and the (poly) oxypropylene chain means an oxypropylene group or a polyoxypropylene group.

  In addition, in the present specification, the term "process" is not limited to an independent process, but may be used in this term if the intended function of the process is achieved even if it can not be clearly distinguished from other processes. included. Moreover, the numerical range shown using "-" in this specification shows the range which includes the numerical value described before and after "-" as minimum value and the maximum value, respectively.

  Furthermore, in the present specification, when there are a plurality of substances corresponding to each component in the composition, the content of each component in the composition is the total amount of the plurality of substances present in the composition unless otherwise specified. Means

  The protective film of the electrode for a touch panel of the present invention is for a touch panel obtained by curing a predetermined portion of a photosensitive layer comprising a photosensitive resin composition containing a binder polymer, a photopolymerizable compound, and a photopolymerization initiator. It is a protective film of an electrode, and is characterized in that heptanonitrile and benzoic acid are detected by pyrolysis gas chromatography mass spectrometry.

  In the specification of the present application, pyrolysis gas chromatography mass spectrometry of the protective film performs gas chromatography mass spectrometry on the gas generated by heating the measurement sample at 140 ° C. Although the heating time of said measurement sample should just be in the range of 1 to 60 minutes, it is preferable that it is 30 minutes. The measurement conditions for pyrolysis gas chromatography mass spectrometry are shown below.

(Measurement conditions for pyrolysis gas chromatography mass spectrometry)
Measuring device: GC / MS QP-2010 (manufactured by Shimadzu Corporation, product name)
Column: HP-5MS (manufactured by Agilent Technologies, product name)
Oven Temp: Heat to 300 ° C at a rate of 15 ° C / min after heating for 5 minutes at 40 ° C Carrier gas: Helium, 1.0 mL / min
Interface temperature: 280 ° C
Ion source temperature: 250 ° C
Sample injection volume: 0.1 mL

  The detection peak area of benzoic acid in the pyrolysis gas chromatography mass spectrometry of the protective film is preferably 1 to 10%, more preferably 1 to 9% with respect to the detection peak area of heptanonitrile. It is more preferably 1 to 7%, particularly preferably 1 to 6%. If the detection peak area of benzoic acid is 1 to 10%, it has the desired shape and is excellent in transparency, and the effect of the present invention of having sufficient rust resistance even with a thin film is obtained more reliably. be able to.

  Next, the photosensitive element and photosensitive resin composition which can be used to obtain the protective film of the electrode for a touch panel of the present invention will be described.

  FIG. 1 is a schematic cross-sectional view showing an embodiment of a photosensitive element used to form a protective film for a touch panel electrode according to the present invention. The photosensitive element 1 shown in FIG. 1 includes a support film 10, a photosensitive layer 20 made of the photosensitive resin composition according to the present embodiment provided on the support film 10, and the support film 10 of the photosensitive layer 20. It consists of a protective film 30 provided on the opposite side.

  The protective film of the electrode for a touch panel of the present invention can be formed by using the photosensitive element.

  In the present specification, the touch panel electrode includes not only the electrode in the sensing area of the touch panel but also the metal wiring of the frame area. The electrode provided with the protective film may be either one or both.

  A polymer film can be used as the support film 10. Examples of the polymer film include films made of polyethylene terephthalate, polycarbonate, polyethylene, polypropylene, polyether sulfone and the like.

  The thickness of the support film 10 is preferably 5 to 100 μm, and is 10 to 70 μm from the viewpoint of securing the covering property and suppressing the decrease in resolution when the actinic light is irradiated through the support film 10. The thickness is more preferably 15 to 40 μm, and particularly preferably 20 to 35 μm.

  The photosensitive resin composition according to the present embodiment constituting the photosensitive layer 20 comprises a binder polymer (hereinafter also referred to as component (A)), a photopolymerizable compound (hereinafter also referred to as component (B)), and photopolymerization. And an initiator (hereinafter, also referred to as component (C)). The said photosensitive resin composition can be made to contain the component which a heptanonitrile and a benzoic acid generate | occur | produce in thermal decomposition of the said hardened | cured material, when it is set as hardened | cured material by irradiation of an actinic light. In the protective film formed from the photosensitive resin composition containing such components, heptanonitrile and benzoic acid are detected by the above-mentioned pyrolysis gas chromatography mass spectrometry.

  As the component (A), for example, a polymer having a carboxyl group can be used.

  In the present embodiment, the component (A) is preferably a copolymer containing a structural unit derived from (a) (meth) acrylic acid and (b) (meth) acrylic acid alkyl ester.

  Examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, (meth) acrylic acid 2-ethylhexyl ester, And acrylic acid hydroxyl ethyl ester.

  The above-mentioned copolymer may further contain other monomers copolymerizable with the above-mentioned (a) component and / or (b) component in a structural unit.

  Examples of other monomers copolymerizable with the above-mentioned component (a) and / or component (b) include (meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl ester, (meth) acrylic Acid diethylaminoethyl ester, (meth) acrylic acid glycidyl ester, (meth) acrylic acid benzyl ester, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate And (meth) acrylamide, (meth) acrylonitrile, diacetone (meth) acrylamide, styrene, and vinyl toluene. When the binder polymer which is the component (A) is synthesized, the above-mentioned monomers may be used alone or in combination of two or more.

  The weight average molecular weight of the binder polymer which is the component (A) is preferably 10,000 to 200,000, more preferably 15,000 to 150,000, from the viewpoint of resolution, and 30,000 to It is more preferably 150,000, particularly preferably 30,000 to 100,000, and very preferably 40,000 to 100,000. In addition, the measurement conditions of a weight average molecular weight are taken as the measurement conditions same as the Example of this-application specification.

  The acid value of the binder polymer which is the component (A) can be 75 mg KOH / g or more from the viewpoint of easily forming a protective film having a desired shape, and the controllability of the protective film shape and prevention of the protective film It is preferable that it is 75 to 200 mgKOH / g from the viewpoint of achieving coexistence with rust property, It is more preferable that it is 75 to 150 mgKOH / g, It is still more preferable that it is 75 to 120 mgKOH / g.

The acid value of the binder polymer which is the component (A) can be measured as follows. That is, first, 1 g of the binder polymer which is an object to be measured of the acid value is precisely weighed. Add 30 g of acetone to the precisely weighed binder polymer and dissolve it uniformly. Then, an appropriate amount of phenolphthalein which is an indicator is added to the solution, and titration is performed using a 0.1 N aqueous KOH solution. And an acid value is computed by following Formula.
Acid value = 0.1 x Vf x 56.1 / (Wp x I / 100)
In the formula, Vf represents the titration volume (mL) of the aqueous KOH solution, Wp represents the weight (g) of the solution containing the binder polymer measured, and I represents the proportion (mass) of nonvolatile matter in the solution containing the binder polymer measured %) Is shown.
In addition, when mix | blending the binder polymer in the state mixed with volatile components, such as a synthetic | combination solvent and a dilution solvent, it heats beforehand at temperature higher 10 degreeC or more than the boiling point of volatile content for 1 to 4 hours before precise weighing beforehand. Remove acid and measure acid value.

  The hydroxyl value of the binder polymer which is the component (A) is preferably 50 mg KOH / g or less, more preferably 45 mg KOH / g or less, from the viewpoint of further improving the corrosion resistance.

The hydroxyl value of the component (A) can be measured as follows.
First, 1 g of a binder polymer, which is an object of measurement of a hydroxyl value, is precisely weighed. 10 mL of a 10% by mass anhydrous acetic anhydride solution is added to the precisely weighed lower binder polymer to dissolve it uniformly and heated at 100 ° C. for 1 hour. After heating, 10 mL of water and 10 mL of pyridine are added and heated at 100 ° C. for 10 minutes. Then, it measures by carrying out neutralization titration by the ethanol solution of 0.5 mol / L potassium hydroxide using an automatic titrator (Hiranuma Sangyo Co., Ltd. "COM-1700").
The hydroxyl value can be calculated by the following equation.
Hydroxyl number = (A−B) × f × 28.05 / sample (g) + acid number In the formula, A represents the amount (mL) of the 0.5 mol / L potassium hydroxide ethanol solution used in the blank test, B shows the quantity (mL) of 0.5 mol / L potassium hydroxide ethanol solution used for titration, and f shows a factor.
In addition, when mix | blending the binder polymer in the state mixed with the synthetic | combination solvent or the dilution solvent, it heats beforehand for 1 to 4 hours at temperature higher 10 degreeC or more than the boiling point of the said synthetic solvent or dilution solvent, The said solvent was removed Then measure the hydroxyl value.

  As a photopolymerizable compound which is (B) component, the photopolymerizable compound which has an ethylenically unsaturated group can be used.

  Examples of the photopolymerizable compound having an ethylenically unsaturated group include a monofunctional vinyl monomer, a bifunctional vinyl monomer, and a polyfunctional vinyl monomer having at least three polymerizable ethylenically unsaturated groups.

  As the monofunctional vinyl monomer, for example, (meth) acrylic acid, (meth) acrylic acid alkyl ester exemplified as a monomer used for the synthesis of a copolymer which is a suitable example of the above-mentioned (A) component Polymerizable monomers may be mentioned.

  Examples of the bifunctional vinyl monomer include polyethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, polypropylene glycol di (meth) acrylate, and bisphenol A polyoxyethylene polyoxypropylene di (meth) acrylate (2 , 2-Bis (4- (meth) acryloxypolyethoxypolypropoxyphenyl) propane), bisphenol A diglycidyl ether di (meth) acrylate etc., polyvalent carboxylic acid (phthalic anhydride etc.) and hydroxyl group and ethylenic unsaturation Esterified products with substances having a group (β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, etc.) can be mentioned.

  Examples of the polyfunctional vinyl monomer having at least three polymerizable ethylenic unsaturated groups include trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, and tetramethylolmethane tetra (meth) acrylate, for example. A compound obtained by reacting an α, β-unsaturated saturated carboxylic acid with a polyhydric alcohol such as dipentaerythritol penta (meth) acrylate or dipentaerythritol hexa (meth) acrylate; such as trimethylolpropane triglycidyl ether triacrylate The compound obtained by adding an (alpha), (beta)-unsaturated carboxylic acid to a glycidyl group containing compound is mentioned.

  Among these, it is preferable to contain a polyfunctional vinyl monomer having at least three polymerizable ethylenically unsaturated groups. Furthermore, from the viewpoint of suppressing electrode corrosion and ease of development, it has a (meth) acrylate compound having a skeleton derived from pentaerythritol, a (meth) acrylate compound having a skeleton derived from dipentaerythritol, and a skeleton derived from trimethylolpropane It is preferable to include at least one selected from (meth) acrylate compounds, and (meth) acrylate compounds having a skeleton derived from dipentaerythritol and at least one selected from (meth) acrylate compounds having a skeleton derived from trimethylolpropane It is more preferable to include one.

  Here, a (meth) acrylate having a skeleton derived from dipentaerythritol means an esterified product of dipentaerythritol and (meth) acrylic acid, and the esterified compound is a compound modified with an alkyleneoxy group. Is also included. The above esterified compound preferably has 6 ester bonds in one molecule, but compounds having 1 to 5 ester bonds may be mixed.

  In addition, the (meth) acrylate compound having a skeleton derived from trimethylolpropane means an esterified product of trimethylolpropane and (meth) acrylic acid, and the esterified product is modified with an alkyleneoxy group. Compounds are also included. In the above-mentioned esterified compound, the number of ester bonds in one molecule is preferably 3, but a compound in which the number of ester bonds is 1 to 2 may be mixed.

  The above compounds can be used alone or in combination of two or more.

  When a monomer having at least three polymerizable ethylenic unsaturated groups in a molecule is used in combination with a monofunctional vinyl monomer or a bifunctional vinyl monomer, the ratio to be used is not particularly limited, but photocurability and electrode corrosion The ratio of the monomer having at least three polymerizable ethylenic unsaturated groups in the molecule is 100 parts by mass relative to the total amount of the photopolymerizable compounds contained in the photosensitive resin composition from the viewpoint of obtaining the suppression power of The amount is preferably 30 parts by mass or more, more preferably 50 parts by mass or more, and still more preferably 75 parts by mass or more.

  The content of the components (A) and (B) in the photosensitive resin composition according to the present embodiment is 35 for the component (A) per 100 parts by mass of the total amount of the components (A) and (B). It is preferable that the amount of the component (B) is 85 to 65 parts by mass, the amount of the component (A) is 40 to 80 parts by mass, and the amount of the component (B) is 20 to 60 parts by mass. More preferably, the component A) is 50 to 70 parts by mass, the component (B) is 30 to 50 parts by mass, the component (A) is 55 to 65 parts by mass, and the component (B) is 35 to 45 parts by mass. Is particularly preferred. In particular, in terms of maintaining transparency and forming a pattern, the content of the (A) component and the (B) component is (A) relative to 100 parts by mass of the total amount of the (A) component and the (B) component. The component is preferably 35 parts by mass or more, more preferably 40 parts by mass or more, still more preferably 50 parts by mass or more, and particularly preferably 55 parts by mass or more.

  By setting the content of the component (A) and the component (B) in the above range, sufficient sensitivity can be obtained while sufficiently securing film properties of the coatability or the photosensitive element, and photocurability, development It is possible to sufficiently secure the resistance and the suppression of electrode corrosion.

  It is preferable that the photosensitive resin composition which concerns on this embodiment contains an oxime ester compound as a photoinitiator which is (C) component. By containing the oxime ester compound, a resin cured film pattern can be formed on the base material with sufficient resolution, even for a thin film having a thickness of 10 μm or less. Furthermore, a resin cured film pattern excellent in transparency can also be formed.

  As an oxime ester compound, the compound represented by the following general formula (C-1) is mentioned.

In the general formula ^{(C-1), R} 1 represents an alkyl group having 1 to 12 carbon atoms, or a cycloalkyl group having 3 to 20 carbon atoms. In addition, as long as the effect of the present invention is not inhibited, the aromatic ring in the above general formula (C-1) may have a substituent.

In the above general formula (C-1), R ¹ is preferably an alkyl group having 3 to 10 carbon atoms or a cycloalkyl group having 4 to 15 carbon atoms, and is an alkyl group having 4 to 8 carbon atoms, or the carbon number More preferably, it is a 4 to 10 cycloalkyl group.

  Examples of the compound represented by the above general formula (C-1) include (1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], etc. 1, 2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)] is available as IRGACURE OXE 01 (manufactured by BASF Corp., trade name).

  Among the above general formula (C-1), 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)] is particularly preferable. In this case, the thermal decomposition gas chromatograph mass of 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)] is formed on the protective film formed from the resin composition according to the present embodiment. When analyzed, it is detected as heptanonitrile and benzoic acid. In addition, the detection peak area of benzoic acid in pyrolysis gas chromatography mass spectrometry of the protective film obtained in this case is preferably 1 to 10%, and 1 to 9% with respect to the detection peak area of heptanonitrile. Is more preferably, 1 to 7% is further preferable, and 1 to 6% is particularly preferable. If the detection peak area of benzoic acid is 1 to 10%, it has the desired shape and is excellent in transparency, and the effect of the present invention of having sufficient rust resistance even with a thin film is obtained more reliably. be able to.

  Component (C) can also be used in combination with a photopolymerization initiator other than the oxime ester compound. Examples of the photopolymerization initiator other than the oxime ester compound include benzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2 Aromatic ketones such as -methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether, benzoin, methyl benzoin, ethyl Benzoin compounds such as benzoin; benzyl derivatives such as benzyl dimethyl ketal; 9-phenylacridine, acridine derivatives such as 1,7-bis (9,9'-acridinyl) heptane; N-phenylglycine, N-phenylglycine derivatives; Emissions-based compound; oxazole-based compounds. Further, as in the combination of diethylthioxanthone and dimethylaminobenzoic acid, the thioxanthone compound and the tertiary amine compound may be combined.

  The content of the photopolymerization initiator which is the component (C) is preferably 0.1 to 20 parts by mass, and 1 to 10 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B). It is more preferable that it is a part, and it is further more preferable that it is 2 to 5 mass parts.

  The content of the component (C) is preferably 0.1 parts by mass or more in terms of excellent photosensitivity and resolution, and is preferably 20 parts by mass or less in terms of excellent visible light transmittance.

  The photosensitive resin composition according to the present embodiment is a triazole compound having a mercapto group, a tetrazole compound having a mercapto group, a thiadiazole compound having a mercapto group, and an amino group, from the viewpoint of further improving the corrosion resistance of the protective film. It is preferable to further contain a triazole compound or a tetrazole compound having an amino group (hereinafter, also referred to as component (D)). Examples of triazole compounds having a mercapto group include 3-mercapto-triazole (manufactured by Wako Pure Chemical Industries, Ltd., trade name: 3 MT). Further, as a thiadiazole compound having a mercapto group, for example, 2-amino-5-mercapto-1,3,4-thiadiazole (manufactured by Wako Pure Chemical Industries, Ltd., trade name: ATT) can be mentioned.

  As the triazole compound having an amino group, a compound in which an amino group is substituted to benzotriazole, 1H-benzotriazole-1-acetonitrile, benzotriazole-5-carboxylic acid, 1H-benzotriazole-1-methanol, carboxybenzotriazole, etc. The compound which the amino group substituted by the triazole compound containing mercapto groups, such as 3-mercapto triazole and 5-mercapto triazole, is mentioned.

Among these, it is preferable that the compound which the amino group substituted by the triazole compound containing a mercapto group from a viewpoint which can reduce a development residue more is preferable. Specifically, for example, 3-amino-5-mercaptotriazole (manufactured by BASF Corp., trade name: AMT) can be mentioned.

  As a tetrazole compound which has the said amino group, the compound represented by the following general formula (D-1) is mentioned.

R ¹¹ and R ¹² in the above general formula (D-1) each independently represent hydrogen, an alkyl group having 1 to 20 carbon atoms, an amino group, a mercapto group or a carboxymethyl group, and R ¹¹ and R ¹² At least one of them has an amino group.

  As an alkyl group, a methyl group, an ethyl group, a propyl group etc. are mentioned.

  Among the tetrazole compounds represented by the above general formula (D-1), 5-amino-1H-tetrazole, 1-methyl-5-amino-tetrazole, 1-methyl-5-mercapto-1H-tetrazole, or Carboxymethyl-5-amino-tetrazole is preferred.

  The tetrazole compound represented by the above general formula (D-1) is preferably the water-soluble salt thereof. Specific examples thereof include alkali metal salts such as sodium, potassium and lithium of 1-methyl-5-amino-tetrazole.

  Among these, 5-amino-1H-tetrazole and 1-methyl-5-mercapto-1H-tetrazole are particularly preferable from the viewpoint of suppressing electrode corrosion, adhesion to a metal electrode, ease of development and transparency.

  These tetrazole compounds and their water-soluble salts may be used alone or in combination of two or more.

  In addition, from the viewpoint of further improving the corrosion resistance when the electrode surface on which the protective film is provided has a metal such as copper, copper alloy, nickel alloy, etc., the photosensitive resin composition has an amino group-containing tetrazole compound or mercapto It is preferable to further contain a compound in which an amino group is substituted to a triazole compound containing a group. In this case, development residues can be reduced, and it becomes easy to form a protective film with a good pattern. As the reason for this, it is considered that appropriate adhesion of the surface is developed.

  When the tetrazole compound having an amino group or the triazole compound containing a mercapto group contains a compound in which an amino group is substituted, the above effects can be obtained, so the photosensitive resin composition and the photosensitive element according to the present embodiment are It is suitable for formation of the protective film for protecting the electrode in the frame area of the touch panel which formed metal layers, such as copper, and improved conductivity.

  The content of the component (D) in the photosensitive resin composition according to the present embodiment is 0.05 to 10.0 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B). Is preferable, 0.1 to 2.0 parts by mass is more preferable, and 0.2 to 1.0 parts by mass is more preferable.

  By the way, when providing a protective film on a part of ITO electrode of a touch panel, for example, the part which formed metal layers, such as copper, on ITO electrode and ITO electrode of a frame area, without forming a protective film in a sensing area. In the case where a protective film is provided on the entire surface, the photosensitive layer is provided on the entire surface, and then exposure and development can be performed to remove unnecessary portions. In this case, the photosensitive layer is required to have a good developability so as not to cause an undeveloped part in unnecessary portions while having sufficient adhesion to the electrode to be protected. From the viewpoint of achieving both adhesion in such a case and developability, the photosensitive resin composition of the present invention contains a phosphate ester containing a photopolymerizable unsaturated bond (hereinafter, also referred to as component (E)). It is preferable to do.

  As a phosphate ester containing a photopolymerizable unsaturated bond, which is the component (E), from the viewpoint of achieving both adhesion to an ITO electrode and developability at a high level while sufficiently securing the corrosion resistance of the protective film to be formed. From the above, it is preferable to use a compound having the following structure as the phosphoric acid ester. The said compound is commercially available products, such as PM21 (made by Nippon Kayaku Co., Ltd.).

  In the photosensitive resin composition according to the present embodiment, in addition, as necessary, an adhesion imparting agent such as a silane coupling agent, a leveling agent, a plasticizer, a filler, an antifoaming agent, a flame retardant, a stabilizer, About 0.01 to 20 parts by mass of an antioxidant, a perfume, a thermal crosslinking agent, a polymerization inhibitor and the like can be contained with respect to 100 parts by mass of the total amount of the (A) component and the (B) component. These can be used alone or in combination of two or more.

  Here, the visible light transmittance of the photosensitive resin composition is determined as follows. First, a coating solution containing a photosensitive resin composition is coated on a support film so that the thickness after drying is 10 μm or less, and the photosensitive resin composition layer (photosensitive layer) is formed by drying this. Form. Next, it laminates using a laminator so that the photosensitive resin composition layer (photosensitive layer) may be in contact with the glass substrate. Thus, a measurement sample in which the photosensitive resin composition layer and the support film are laminated on the glass substrate is obtained. Next, after irradiating an ultraviolet-ray to the obtained sample for a measurement and photocuring the photosensitive resin composition layer, the transmittance | permeability in measurement wavelength area 400-700 nm is measured using a UV visible spectrophotometer.

  In addition, the suitable transmittance | permeability mentioned above means the minimum value of the transmittance | permeability in the said wavelength range.

  When the transmittance in the wavelength range of 400 to 700 nm, which is a light beam in a general visible light wavelength range, is 90% or more, the case of protecting the transparent electrode in the sensing region of the touch panel (touch sensor), or the touch panel (touch sensor) When a protective film is seen from the end of the sensing area when the metal layer in the frame area of the frame (for example, a layer in which a copper layer is formed on an ITO electrode) is protected, the image display quality, color tone, and brightness in the sensing area The decrease can be sufficiently suppressed.

  The photosensitive resin composition according to the present embodiment can be used to form a photosensitive layer on a substrate. For example, a coating solution which can be obtained by uniformly dissolving or dispersing the photosensitive resin composition in a solvent is prepared, a coating film is formed by applying on a substrate, and a solvent is removed by drying. Layers can be formed.

  As the solvent, ketone, aromatic hydrocarbon, alcohol, glycol ether, glycol alkyl ether, glycol alkyl ether acetate, ester, or diethylene glycol is used from the viewpoint of solubility of each component, ease of forming a coating film, etc. Can. One of these solvents may be used alone, or a mixture of two or more solvents may be used.

  Among the above solvents, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate and the like are preferably used.

  The photosensitive resin composition according to the present embodiment is preferably used by forming a film on a photosensitive film as in the case of the photosensitive element 1. By laminating a photosensitive film on a substrate having an electrode for a touch panel, a roll-to-roll process can be easily realized, a solvent drying process can be shortened, and the like, which greatly contributes to shortening of the manufacturing process and cost reduction. it can.

  The photosensitive layer 20 of the photosensitive element 1 can be formed by preparing a coating solution containing the photosensitive resin composition according to the present embodiment, and coating and drying this on the support film 10. A coating liquid can be obtained by melt | dissolving uniformly or disperse | distributing each component which comprises the photosensitive resin composition which concerns on this embodiment mentioned above in a solvent.

  The solvent is not particularly limited, and known ones can be used. For example, acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, methanol, ethanol, propanol, butanol, methylene glycol, ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, Ethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, chloroform, methylene chloride can be mentioned. One of these solvents may be used alone, or a mixture of two or more solvents may be used.

  As a coating method, for example, doctor blade coating method, Mayer bar coating method, roll coating method, screen coating method, spinner coating method, inkjet coating method, spray coating method, dip coating method, gravure coating method, curtain coating method, die The coating method is mentioned.

  The drying conditions are not particularly limited, but the drying temperature is preferably 60 to 130 ° C., and the drying time is preferably 0.5 to 30 minutes.

  The thickness of the photosensitive layer is 1 μm or more and 9 μm or less after drying so that the surface of the touch panel (touch sensor) produced by partial electrode protective film formation has a sufficient effect by exerting a sufficient effect on electrode protection. It is preferably 1 μm to 8 μm, more preferably 2 μm to 8 μm, and particularly preferably 3 μm to 8 μm.

  In the present embodiment, the photosensitive layer 20 preferably has a minimum visible light transmittance of 90% or more, more preferably 92% or more, and still more preferably 95% or more.

  The viscosity of the photosensitive layer 20 prevents the photosensitive resin composition from exuding from the end face of the photosensitive element 1 for one month or more when the photosensitive element is in the form of a roll, and when cutting the photosensitive element 1 It is preferable that the viscosity is 30 to 100 mPa · s at 30 ° C. from the viewpoint of preventing exposure defects, development residue, etc. when irradiating active light rays caused by adhesion of fragments of the photosensitive resin composition to the substrate. The viscosity is more preferably 20 to 90 mPa · s, and still more preferably 25 to 80 mPa · s.

The above viscosity is a circular film of 7 mm in diameter and 2 mm in thickness formed from the photosensitive resin composition as a measurement sample, and 1.96 × at 30 ° C. and 80 ° C. in the thickness direction of this sample. The rate of change in thickness when a load of 10 ⁻² N is applied is measured, and the rate of change is a value converted to viscosity assuming a Newtonian fluid.

  Examples of the protective film 30 (cover film) include films made of polyethylene, polypropylene, polyethylene terephthalate, polycarbonate, polyethylene-vinyl acetate copolymer, and a laminated film of polyethylene-vinyl acetate copolymer and polyethylene.

  The thickness of the protective film 30 is preferably about 5 to 100 μm, but it is preferably 70 μm or less, more preferably 60 μm or less, and further preferably 50 μm or less from the viewpoint of winding and storing in a roll shape. Preferably, it is 40 μm or less.

  The photosensitive element 1 can be rolled and stored or used.

  In the present embodiment, a coating liquid containing the photosensitive resin composition according to the above-described present embodiment and a solvent is applied on a substrate having an electrode for a touch panel, and dried to form a photosensitive resin composition. A photosensitive layer 20 may be provided. Also in the case of this application, it is preferable that the photosensitive layer satisfy the above-mentioned film thickness and visible light transmittance.

  Next, a method of forming a protective film for a touch panel electrode according to the present invention will be described. FIG. 2: is a schematic cross section for demonstrating an example of the formation method of the protective film of the electrode for touch panels which concerns on this invention.

  In the method of forming a protective film for a touch panel electrode according to the present embodiment, a first photosensitive layer 20 made of the photosensitive resin composition according to the present embodiment is provided on the substrate 100 having the touch panel electrodes 110 and 120. And a second step of curing a predetermined portion of the photosensitive layer 20 by irradiation with actinic radiation including ultraviolet light, and removing the photosensitive layer other than the predetermined portion after the irradiation of the actinic radiation and exposing a part or all of the electrode And the third step of forming a protective film 22 composed of a cured film pattern of the transparent resin composition. Thus, a protective film-equipped touch panel (touch sensor) 200 which is a touch input sheet is obtained.

  As the base material 100 used by this embodiment, board | substrates, such as a glass plate, a plastic plate, a ceramic plate, etc. which are generally used for touch panels (touch sensor) are mentioned. An electrode for a touch panel to be a target for forming a cured resin film to be a protective film is provided on the substrate. Examples of the electrode include an electrode of ITO, Cu, Al, Mo or the like, a TFT or the like. In addition, an insulating layer may be provided on the substrate between the substrate and the electrode.

  The substrate 100 having the touch panel electrodes 110 and 120 shown in FIG. 2 can be obtained, for example, by the following procedure. After forming a metal film by sputtering in the order of ITO and Cu on a substrate 100 such as a PET film, a photosensitive film for etching is attached on the metal film, a desired resist pattern is formed, and unnecessary Cu is chlorinated After removing with an etching solution such as an aqueous iron solution, the resist pattern is peeled off.

  In the first step, after removing the protective film 30 of the photosensitive element 1 according to the present embodiment, the photosensitive element is heated, and the surface of the substrate 100 on which the touch panel electrodes 110 and 120 are provided is exposed. The layer 20 is transferred by pressure bonding and transferred (see FIG. 2A).

  As a pressure bonding means, a pressure bonding roll can be mentioned. The pressure roll may be provided with a heating means so as to be capable of heat pressure bonding.

  The heating temperature in the case of thermocompression bonding is a component of the photosensitive layer 20 while sufficiently securing the adhesion between the photosensitive layer 20 and the base 100 and the adhesion between the photosensitive layer 20 and the touch panel electrodes 110 and 120. The temperature is preferably 10 to 160 ° C., more preferably 20 to 150 ° C., and still more preferably 30 to 150 ° C. so as to be hard to be thermally cured or thermally decomposed.

Further, from the viewpoint of suppressing deformation of the base material 100, the bonding pressure at the time of thermocompression bonding is 50 to 1 × 10 ⁵ N / m from the viewpoint of suppressing deformation of the base material 100 while sufficiently securing the adhesion between the photosensitive layer 20 and the base material 100. It is preferable to set it as 2.5 * 10 < ² > -5 * 10 < ⁴ > N / m, It is more preferable to set it as 5 * 10 < ² > -4 * 10 < ⁴ > N / m.

  Although it is not necessary to preheat the substrate by heating the photosensitive element 1 as described above, the substrate 100 is preheated from the viewpoint of further improving the adhesion between the photosensitive layer 20 and the substrate 100. It is preferable to do. The preheating temperature at this time is preferably 30 to 150 ° C.

  In the method according to the present embodiment, instead of using the photosensitive element, the coating liquid containing the photosensitive resin composition according to the present embodiment and the solvent is prepared to provide the electrodes 110 and 120 for the touch panel of the substrate 100. The photosensitive layer 20 can be formed by coating on the surface of the substrate and drying.

  The photosensitive layer 20 preferably satisfies the conditions of the film thickness and the visible light transmittance described above.

  In the second step, a predetermined portion of the photosensitive layer 20 is irradiated with an actinic ray L in a pattern via the photomask 130 (see (b) of FIG. 2).

  When the actinic ray is irradiated, if the support film 10 on the photosensitive layer 20 is transparent, the actinic ray can be irradiated as it is, and if it is opaque, it is removed and then the actinic ray is irradiated. From the viewpoint of protection of the photosensitive layer 20, it is preferable to use a transparent polymer film as the support film 10 and to irradiate actinic radiation through the polymer film while it is left.

  As a light source of actinic light used for irradiation of actinic light L, a known active light source can be used. For example, a carbon arc lamp, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a xenon lamp etc. may be mentioned. There is no particular limitation as long as

The irradiation amount of the actinic ray L at this time is usually 1 × 10 ² to 1 × 10 ⁴ J / m ² and may be accompanied by heating at the time of irradiation. If the actinic ray irradiation amount is less than 1 × 10 ² J / m ² , the photocuring effect tends to be insufficient, and if it exceeds 1 × 10 ⁴ J / m ² , the photosensitive layer 20 tends to be discolored. There is.

  In the third step, the photosensitive layer after irradiation with actinic light is developed with a developer to remove a portion not irradiated with the actinic light (that is, other than a predetermined portion of the photosensitive layer), and a part or all of the electrode is removed. The protective film 22 which consists of a cured film pattern of the photosensitive resin composition which concerns on this embodiment whose thickness to coat | cover is 10 micrometers or less is formed (refer (c) of FIG. 2). The protective film 22 to be formed can have a predetermined pattern.

  When the support film 10 is laminated on the photosensitive layer 20 after irradiation with actinic light, the support film 10 is removed, and then development is performed to remove a portion which is not irradiated with actinic light by the developer.

  As a developing method, using a known developing solution such as an aqueous alkali solution, an aqueous developing solution, an organic solvent, etc., development is performed by a known method such as spraying, showering, swing immersion, brushing, scraping, etc. Among them, it is preferable to use an alkaline aqueous solution from the viewpoint of environment and safety.

  As a base of the aqueous alkali solution, alkali hydroxide (lithium, sodium or potassium hydroxide etc.), alkali carbonate (lithium, sodium or potassium carbonate or bicarbonate etc.), alkali metal phosphate (potassium phosphate) Sodium phosphate, etc.), alkali metal pyrophosphates (sodium pyrophosphate, potassium pyrophosphate etc.), tetramethyl ammonium hydroxide, triethanolamine etc., among which tetramethyl ammonium hydroxide etc. is mentioned as preferable. Be

  Further, an aqueous solution of sodium carbonate is also preferably used, and for example, a dilute solution (0.5 to 5% by mass aqueous solution) of sodium carbonate at 20 to 50 ° C. is suitably used.

  The development temperature and time can be adjusted in accordance with the developability of the photosensitive resin composition according to the present embodiment.

  In addition, in the alkaline aqueous solution, a surfactant, an antifoaming agent, a small amount of an organic solvent for accelerating development, and the like can be mixed.

  After development, the base of the aqueous alkali solution remaining in the photosensitive layer 20 after photocuring is subjected to a known method such as spraying, rocking immersion, brushing or scraping using an organic acid, an inorganic acid or an aqueous solution of these acids. It can be acid treated (neutralized).

  Furthermore, after the acid treatment (neutralization treatment), a step of washing with water can also be performed.

After development, if necessary, the cured film pattern may be further cured by irradiation with an actinic ray (for example, 5 × 10 ³ to 2 × 10 ⁴ J / m ² ). In addition, although the photosensitive resin composition which concerns on this embodiment shows the outstanding adhesiveness with respect to a metal, without the heating process after image development, as needed, instead of irradiation of the actinic light after image development, or A heat treatment (80 to 160 ° C.) may be performed in combination with the irradiation of the actinic rays.

  As described above, the protective film for the touch panel electrode according to the present invention can be formed.

  Examples of detection as heptanonitrile and benzoic acid by pyrolysis gas chromatography mass spectrometry of the protective film include, as described above, the photosensitive resin composition constituting the photosensitive layer, as the component (C) 1, 2 or 3 -The case containing octanedione, 1- [4- (phenylthio)-, 2- (O- benzoyl oxime)] is mentioned.

  Next, an example of the use place of the protective film of the present invention will be described using FIG. 3, FIG. 4 and FIG. FIG. 3 is a schematic top view showing an example of a capacitive touch panel. The touch panel shown in FIG. 3 has a touch screen 102 for detecting touch position coordinates on one side of a transparent substrate 101, and a transparent electrode 103 and a transparent electrode 104 for detecting a capacitance change in this area are the substrate 101. It is provided on top. The transparent electrode 103 and the transparent electrode 104 detect the X coordinate and the Y coordinate of the touch position, respectively.

  On the transparent substrate 101, a lead wire 105 for transmitting a detection signal of a touch position from the transparent electrode 103 and the transparent electrode 104 to an external circuit is provided. Further, the lead wire 105 is connected to the transparent electrode 103 and the transparent electrode 104 by the transparent electrode 103 and the connection electrode 106 provided on the transparent electrode 104. Further, a connection terminal 107 to an external circuit is provided at an end of the lead wire 105 opposite to the connection portion with the transparent electrode 103 and the transparent electrode 104. The photosensitive resin composition according to the present invention can be suitably used to form the protective film 122 of the lead wire 105, the connection electrode 106, and the connection terminal 107. At this time, it is also possible to simultaneously protect the electrodes in the sensing area. Although in FIG. 3 the lead-out wiring 105, the connection electrode 106, the partial electrode of the sensing region, and a part of the connection terminal 107 are protected by the protective film 122, the portion where the protective film is provided may be changed as appropriate. For example, as shown in FIG. 4, a protective film 123 may be provided to protect the touch screen 102 entirely.

  The cross-sectional structure of the connection portion of the transparent electrode and the lead-out wire in the touch panel shown in FIG. 3 will be described using FIG. 5. FIG. 5 is a partial cross-sectional view taken along the line V-V of the portion C shown in FIG. 3 and is a view for explaining a connection portion between the transparent electrode 104 and the lead-out wiring 105. As shown to (a) of FIG. 5, the transparent electrode 104 and the lead-out wiring 105 are electrically connected via the connection electrode 106. As shown in FIG. As shown in FIG. 5A, a part of the transparent electrode 104 and all of the lead-out wiring 105 and the connection electrode 106 are covered with the protective film 122. Similarly, the transparent electrode 103 and the lead wire 105 are electrically connected via the connection electrode 106. In addition, as shown to (b) of FIG. 5, the transparent electrode 104 and the lead-out wiring 105 may be electrically connected directly. The photosensitive resin composition and photosensitive element according to the present embodiment described above are suitable for use for forming a resin cured film pattern as a protective film of the above-mentioned structural part.

  The manufacturing method of the touch panel in this embodiment is explained. First, the transparent electrode (X position coordinate) 103 is formed on the transparent electrode 101 provided on the substrate 100. Subsequently, the transparent electrode (Y position coordinate) 104 is formed. The transparent electrode 103 and the transparent electrode 104 can be formed by etching the transparent electrode layer formed on the transparent substrate 100.

  Next, on the surface of the transparent substrate 101, a lead wire 105 for connecting to an external circuit, and a connection electrode 106 for connecting the lead wire, the transparent electrode 103, and the transparent electrode 104 are formed. The lead wire 105 and the connection electrode 106 may be formed after the formation of the transparent electrode 103 and the transparent electrode 104, or may be formed simultaneously with the formation of each transparent electrode. After the metal sputtering, an etching method or the like can be used to form the lead wiring 105 and the connection electrode 106. The lead-out wiring 105 can be formed at the same time as forming the connection electrode 106 using a conductive paste material containing, for example, flake-like silver, using a screen printing method. Next, a connection terminal 107 for connecting the lead wiring 105 and an external circuit is formed.

  The photosensitive element 1 according to the present embodiment is crimped so as to cover the transparent electrode 103 and the transparent electrode 104, the lead wire 105, the connection electrode 106, and the connection terminal 107 formed by the above steps, and the photosensitive electrode 1 is exposed on the electrode A layer 20 is provided. Next, an actinic ray L is irradiated in a desired shape to the transferred photosensitive layer 20 in a desired shape through a photomask. After the irradiation with the actinic ray L, development is performed to remove a portion other than the predetermined portion of the photosensitive layer 20, thereby forming a protective film 122 made of a cured product of the predetermined portion of the photosensitive layer 20. Thus, the touch panel provided with the protective film 122 can be manufactured.

  Hereinafter, the present invention will be more specifically described by way of examples. However, the present invention is not limited to the following examples.

[Preparation of Binder Polymer Solution (A1)]
(1) shown in Table 1 is charged into a flask equipped with a stirrer, a reflux condenser, an inert gas inlet and a thermometer, the temperature is raised to 80 ° C. under a nitrogen gas atmosphere, and the reaction temperature is 80 ° C. ± 2 (2) shown in Table 1 was dripped uniformly over 4 hours, keeping at ° C. After dropping (2), stirring is continued at 80 ° C. ± 2 ° C. for 6 hours, and a solution of binder polymer having a weight average molecular weight of about 65,000, an acid value of 78 mg KOH / g and a hydroxyl value of 2 mg KOH / g (solid content 45 Mass%) (A1) was obtained.

The weight average molecular weight (Mw) was measured by gel permeation chromatography (GPC), and was derived by conversion using a calibration curve of standard polystyrene. The conditions of GPC are shown below.
GPC conditions Pump: Hitachi L-6000 (manufactured by Hitachi, Ltd., product name)
Column: Gelpack GL-R420, Gelpack GL-R430, Gelpack GL-R440 (manufactured by Hitachi Chemical Co., Ltd., product name)
Eluent: Tetrahydrofuran Measurement temperature: 40 ° C
Flow rate: 2.05 mL / min Detector: Hitachi L-3300 RI (manufactured by Hitachi, Ltd., product name)

[Method of measuring acid number]
Moreover, the acid value was measured as follows. First, the solution of the binder polymer was heated at 130 ° C. for 1 hour to remove volatiles to obtain solid content. Then, 1 g of a polymer whose acid value is to be measured was precisely weighed, and then 30 g of acetone was added to the polymer to dissolve it uniformly. Then, an appropriate amount of phenolphthalein as an indicator was added to the solution, and titration was performed using a 0.1 N aqueous KOH solution. And the acid value was computed by following Formula.
Acid value = 0.1 x Vf x 56.1 / (Wp x I / 100)
In the formula, Vf indicates the titration volume (mL) of the aqueous KOH solution, Wp indicates the weight (g) of the measured resin solution, and I indicates the proportion (mass%) of the nonvolatile matter in the measured resin solution.

[Method of measuring hydroxyl value]
The hydroxyl value was measured as follows. First, the solution of the binder polymer was heated at 130 ° C. for 1 hour to remove volatiles to obtain solid content. Then, 1 g of the polymer whose hydroxyl value is to be measured is precisely weighed, and then the precisely weighed photosensitive resin composition is placed in an Erlenmeyer flask, and 10 mL of a 10% by mass anhydrous acetic anhydride / pyridine solution is added to dissolve it uniformly. Heat at <0> C for 1 hour. After heating, 10 mL of water and 10 mL of pyridine are added, and after heating for 10 minutes at 100 ° C., ethanol of 0.5 mol / L potassium hydroxide is used using an automatic titrator (“COM-1700” manufactured by Hiranuma Sangyo Co., Ltd.) The solution was used for neutralization titration. Then, the hydroxyl value was calculated by the following formula.
Hydroxyl number = (A−B) × f × 28.05 / sample (g) + acid number In the formula, A represents the amount (mL) of the 0.5 mol / L potassium hydroxide ethanol solution used in the blank test, B shows the quantity (mL) of 0.5 mol / L potassium hydroxide ethanol solution used for titration, and f shows a factor.

(Examples 1-8, comparative examples 1-8)
[Preparation of Coating Liquid Containing Photosensitive Resin Composition]
The materials shown in Table 2 were mixed for 15 minutes using a stirrer to prepare a coating solution containing a photosensitive resin composition for forming a protective film.

[Preparation of photosensitive element]
A 50 μm thick polyethylene terephthalate film is used as a support film, and a coating solution containing the photosensitive resin composition prepared above is uniformly coated on the support film using a comma coater, and dried at 100 ° C. with a hot air convection system. The solvent was removed by drying for 3 minutes with a machine to form a photosensitive layer (photosensitive resin composition layer) composed of the photosensitive resin composition. The thickness of the obtained photosensitive layer was 5 μm.

  Then, a polyethylene film of 25 μm thickness was further laminated as a cover film on the obtained photosensitive layer to prepare a photosensitive element for forming a protective film.

[Measurement of permeability of protective film]
While peeling off the polyethylene film which is a cover film of the obtained photosensitive element, a laminator (manufactured by Hitachi Chemical Co., Ltd., trade name: HLM-3000) on a glass substrate with a thickness of 1 mm so that the photosensitive layer is in contact. Since a substrate with a roll temperature of 120 ° C, a substrate feed rate of 1 m / min, and a pressure bonding pressure (cylinder pressure) of 4 × 10 ⁵ Pa (thickness 1 mm, length 10 cm × width 10 cm) was used, the line pressure at this time was 9 It laminated on the conditions of 8 * 10 < ³ > N / m), and produced the laminated body on which the photosensitive layer and the support film were laminated | stacked on the glass substrate.

Then, using a parallel beam exposure machine (EXM 1201 manufactured by Oak Manufacturing Co., Ltd.) for the photosensitive layer of the obtained laminate, the exposure amount is 5 × 10 ² J / m ² from the upper side of the photosensitive layer (i ray After irradiation with ultraviolet light, the support film is removed, and the film is allowed to stand for 30 minutes in a box-type drier (manufactured by Mitsubishi Electric Corporation, model number: NV50-CA) heated to 140 ° C. A sample for transmittance measurement having a protective film with a thickness of 5 μm was obtained.

  Subsequently, the visible light transmittance was measured at a measurement wavelength range of 400 to 700 nm using a UV-visible spectrophotometer (U-3310) manufactured by Hitachi High-Technologies Corp., and the minimum value was calculated. . Tables 4 and 5 show the measurement results.

[Salt spray test of protective film (artificial sweat resistance evaluation test)]
While peeling off the polyethylene film of the obtained photosensitive element, a laminator (trade name: HLM- (Hitachi Chemical Industry Co., Ltd.), so that the photosensitive layer is in contact with the sputtered copper-added polyimide film (Toray Film Processing Co., Ltd.)). The roll temperature is 120 ° C, the substrate feed speed is 1 m / min, and the crimping pressure (cylinder pressure) is 4 × 10 ⁵ Pa (thickness: 1 mm, vertical 10 cm × horizontal 10 cm). The linear pressure was laminated at 9.8 × 10 ³ N / m) to prepare a laminate in which a photosensitive layer and a support film were laminated on sputtered copper.

Then, using a parallel beam exposure machine (EXM 1201 manufactured by Oak Manufacturing Co., Ltd.) for the photosensitive layer of the obtained laminate, an exposure amount of 5 × 10 ² J / m ² from above the photosensitive side (i ray ( Measured values at a wavelength of 365 nm), after irradiation with ultraviolet light, remove the support film, and further from the upper side of the photosensitive layer at a dose of 1 × 10 ⁴ J / m ² (measured values at i ray (wavelength 365 nm)) It was irradiated and was allowed to stand for 30 minutes in a box-type drier (manufactured by Mitsubishi Electric Corporation, model number: NV50-CA) heated to 140 ° C. The artificial sweat fluid resistance evaluation sample in which the 5.0-micrometer-thick protective film was formed was obtained.

Subsequently, the above-mentioned sample is mounted in a test tank using a salt spray tester (Suga Test Instruments Co., Ltd. STP-90V2) with reference to JIS standard (Z 2371), and the salt water of concentration 50g / L (PH = 6.7) was sprayed for 48 hours with a test tank temperature of 35 ° C. and a spray amount of 1.5 mL / h. After the end of spraying, the salt water was wiped off, the surface condition of the sample for evaluation was observed, and evaluation was made according to the following scores. Tables 4 and 5 show the measurement results.
A: No change on the protective film surface.
B: A slight trace is visible on the surface of the protective film, but copper does not change.
C: Traces are visible on the surface of the protective film, but copper is not changed.
D: There are traces on the surface of the protective film, and copper is discolored.

[Measured gas measurement after heating at 140 ° C. for 30 minutes (pyrolysis gas chromatograph mass spectrometry)]
Laminator (Hitachi Chemical Co., Ltd.) so that the photosensitive layer of the polytetrafluoroethylene sheet (made by Nitto Denko Corporation, product name: Nitroflon film No. 900U) is in contact while peeling off the polyethylene film of the obtained photosensitive element. It laminated | stacked on conditions of roll temperature 120 degreeC, board | substrate feed speed 1 m / min, and crimping | compression-bonding pressure (cylinder pressure) 4 * 10 < ⁵ > Pa using the product made from brand name HLM-3000).

Then, using a parallel beam exposure machine (EXM 1201 manufactured by Oak Manufacturing Co., Ltd.) for the photosensitive layer of the obtained laminate, an exposure amount of 5 × 10 ² J / m ² from above the photosensitive side (i ray ( Measured values at a wavelength of 365 nm), after irradiation with ultraviolet light, remove the support film, and further from the upper side of the photosensitive layer at a dose of 1 × 10 ⁴ J / m ² (measured values at i ray (wavelength 365 nm)) The sample was irradiated to obtain a measurement sample for pyrolysis gas chromatograph mass spectrometry.

  After heating the measurement sample to 140 ° C and 30 min using a Tekmar 7000HT head space sampler, the generated gas is GC / MS (manufactured by Shimadzu, model number: GC / MS QP-2010, carrier gas: helium, 1.0 mL / min) , Column: HP-5MS, Oven: After heating at 40 ° C for 5 minutes, temperature rising to 300 ° C at a rate of 15 ° C / min, interface temperature: 280 ° C, ion source temperature: 250 ° C, sample injection amount: 0.1 mL Was introduced and analyzed. Tables 4 and 5 show the measurement results. Moreover, the gas chromatogram at the time of performing pyrolysis gas chromatograph mass spectrometry about the protective film obtained in Example 6 is shown in FIG. In FIG. 6, A shows a detection peak of benzoic acid, and B shows a detection peak of heptanonitrile.

The symbols of the components in Tables 2 and 3 have the following meanings.
(A) Component (A1): Propylene glycol monomethyl ether / toluene solution of copolymer having a monomer blending ratio (methacrylic acid / methyl methacrylate / ethyl acrylate = 12/58/30 (mass ratio)), weight average molecular weight 65,000, acid value 78 mg KOH / g, hydroxyl value 2 mg KOH / g, Tg 60 ° C.

(B) Component A-TMMT: pentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.)
DPHA: dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.)
TMPTA: trimethylolpropane triacrylate (manufactured by Nippon Kayaku Co., Ltd.)
UX-3204: Urethane acrylate (made by Nippon Kayaku Co., Ltd.) containing hydroxyethyl acrylate, polyester diol and hexamethylene diisocyanate as raw material components
PET-30: pentaerythritol triacrylate (manufactured by Nippon Kayaku Co., Ltd.)

(C) Component IRGACURE OXE 01: 1,2-octanedione, 1-[(4-phenylthio)-, 2- (O-benzoyloxime)] (manufactured by BASF Corp.)
IRGACURE 184: 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by BASF Corp.)
IRGACURE 651: 2,2-Dimethoxy-1,2-diphenylethan-1-one (manufactured by BASF Corp.)
IRGACURE 369: 2-benzyl-2-dimethylamino-1- (morpholinophenyl) -butanone-1 (manufactured by BASF Corp.)
IRGACURE 907: 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (manufactured by BASF Corp.)
IRGACURE 2959: 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (manufactured by BASF Corp.)
DETX: 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd.)
N-1717: 1,7-bis (9-acridinyl) heptane (manufactured by ADEKA Corporation)
EAB: 4,4'-bis (diethylamino) benzophenone (made by Hodogaya Chemical Co., Ltd.)

(D) Component HAT: 5-amino-1H-tetrazole (manufactured by Toyobo Co., Ltd.)
AMT: 3-amino-5-mercaptotriazole (manufactured by Wako Pure Chemical Industries, Ltd.)
ATT: 2-amino-5-mercapto-1,3,4-thiadiazole (manufactured by Wako Pure Chemical Industries, Ltd.)
Other components Antage W-500: 2,2'-methylene-bis (4-ethyl-6-tert-butylphenol) (manufactured by Kawaguchi Chemical Co., Ltd.)
PM-21: phosphate ester containing a photopolymerizable unsaturated bond (manufactured by Nippon Kayaku Co., Ltd.)
SH-30: Octamethylcyclotetrasiloxane (manufactured by Toray Dow Corning Co., Ltd.)
Methyl ethyl ketone: manufactured by Tonen Chemical Co., Ltd.

  DESCRIPTION OF SYMBOLS 1 ... photosensitive element, 10 ... support film, 20 ... photosensitive layer, 22 ... protective film, 30 ... protective film, 100 ... base material, 101 ... transparent substrate, 102 ... touch screen, 103 ... transparent electrode (X position coordinate) , 104: transparent electrode (Y position coordinate), 105: lead wire, 106: connection electrode, 107: connection terminal, 110, 120: electrode for touch panel, 122, 123: protective film, 130: photomask, 200: touch panel.

Claims (10)

A protective film for a touch panel electrode obtained by curing a predetermined portion of a photosensitive layer comprising a photosensitive resin composition containing a binder polymer, a photopolymerizable compound, and a photopolymerization initiator,
The photosensitive resin composition further contains a triazole compound having a mercapto group, a tetrazole compound having a mercapto group, a thiadiazole compound having a mercapto group, a triazole compound having an amino group or a tetrazole compound having an amino group,
A protective film for an electrode for a touch panel, in which heptanonitrile and benzoic acid are detected by thermal decomposition gas chromatography mass spectrometry. The protective film for an electrode for a touch panel according to claim 1, wherein the photosensitive resin composition contains a (meth) acrylate compound having a skeleton derived from trimethylolpropane and a thiadiazole compound having a mercapto group. The touch panel according to claim 1 or 2 , wherein a content of the binder polymer in the photosensitive resin composition is 55 to 65 parts by mass with respect to 100 parts by mass of a total amount of the binder polymer and the photopolymerizable compound. Protective film for electrodes. The protective film for a touch panel electrode according to any one of claims 1 to 3 , wherein the touch panel electrode contains copper and is a metal wiring in a frame region of the touch panel. The protective film of the electrode for a touch panel according to any one of claims 1 to 4 , wherein a detection peak area of the benzoic acid in the analysis is 1 to 10% of a detection peak area of the heptanonitrile. . The protective film of the electrode for touchscreens as described in any one of Claims 1-5 whose minimum value of the visible light transmittance | permeability in 400-700 nm is 90% or more. The binder polymer has a carboxyl group, an acid value of 75 mgKOH / g or higher, according to claim 1-6 protective film of the touch panel electrode according to any one of. The protective film for a touch panel electrode according to any one of claims 1 to 7 , wherein the binder polymer has a hydroxyl value of 50 mg KOH / g or less. The protective film of the electrode for touchscreens as described in any one of Claims 1-8 whose thickness is 10 micrometers or less. A touch panel comprising the protective film according to any one of claims 1 to 9 .