TW201331709A - Protective film of electrode for touch panel and touch panel - Google Patents

Abstract

A protective film of an electrode for a touch panel obtained by curing a predetermined portion of a photosensitive layer containing a photosensitive resin composition is provided, wherein the photosensitive resin composition contains a binder polymer, a photopolymerizable compound, and a photopolymerization initiator. Heptonitrile and benzoic acid are detected in the protective film of the electrode for the touch panel by pyrolysis gas chromatography mass spectrometry.

Description

Protective film for touch panel electrode and touch panel

The present invention relates to a touch panel of a protective film for an electrode for a touch panel and a protective film using the electrode for the touch panel.

From large electronic devices such as personal computers or televisions to small electronic devices such as car navigation, mobile phones, electronic dictionaries, or office automation (OA), factory automation (FA) equipment. In a display device such as a liquid crystal display element or a touch panel (touch sensor), a touch panel is always used. An electrode including a transparent conductive electrode material is provided in the liquid crystal display element or the touch panel. Indium-tin oxide (ITO), indium oxide, or tin oxide is known as a transparent conductive electrode material. These materials exhibit high visible light transmittance, and thus are electrodes for substrates such as liquid crystal display elements. Material has become the mainstream.

In the touch panel, various types of touch panels have been put into practical use, and in recent years, the application of the capacitive touch panel is being promoted. In the capacitive touch panel, if the fingertip of the conductor is in contact with the touch input surface, electrostatic capacitance coupling is performed between the fingertip and the conductive film to form a capacitor. Therefore, the capacitive touch panel detects the coordinates of the contact position by capturing the change in the charge at the contact position of the fingertip.

In particular, the projection type electrostatic capacitance type touch panel is practical. Nowadays, there is a multi-point detection of fingertips, so it has good operability for performing complicated instructions. Due to this good operability, the following uses are being promoted, that is, for use as a mobile phone or a portable music player with a small display device. Input device on the display surface in the device.

Generally, in a projection type capacitive touch panel, in order to express two-dimensional coordinates of the X-axis and the Y-axis, a plurality of X electrodes and a plurality of Y electrodes orthogonal to the X electrodes form a two-layer structure. For the electrode, Indium-Tin-Oxide (ITO) has been used.

Moreover, the front edge area of the touch panel is an area where the touch position cannot be detected, so reducing the area of the front edge area is an important factor for improving the value of the product. In the forehead area, metal wiring is required to transmit the detection signal of the touch position, but in order to narrow the margin area, it is necessary to narrow the width of the metal wiring. Since the conductivity of ITO is not sufficiently high, metal wiring is usually formed of copper.

However, the touch panel as described above sometimes invades the inside from the sensing region when a contact component such as moisture or salt is in contact with the fingertip. When the corroded component intrudes into the inside of the touch panel, the metal wiring is corroded, and the electric resistance between the electrode and the driving circuit may increase or break.

In order to prevent corrosion of metal wiring, a capacitive touch panel of a capacitive type in which an insulating layer is formed on a metal is disclosed (for example, Patent Document 1). In the touch panel, a ruthenium dioxide layer is formed on the metal by a plasma chemical vapor deposition (CVD) method to prevent corrosion of the metal. However, this method uses a plasma CVD method, so there is a need for high temperature processing and the substrate is limited. Problems such as high manufacturing costs.

Further, as a method of providing a resist film at a necessary portion, a method is known in which a photosensitive layer containing a photosensitive resin composition is provided on a predetermined substrate, and the photosensitive layer is exposed and developed (for example, Patent Document 2 to Patent Document 4). Further, Patent Document 5 and Patent Document 6 disclose that a protective film of a touch panel is formed by the above method.

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2011-28594

Patent Document 2: Japanese Patent Laid-Open No. Hei 7-253666

Patent Document 3: Japanese Patent Laid-Open Publication No. 2005-99647

Patent Document 4: Japanese Patent Laid-Open No. Hei 11-133617

Patent Document 5: Japanese Patent Laid-Open Publication No. 2010-27033

Patent Document 6: Japanese Patent Laid-Open No. 2011-232584

The production of the protective film using the photosensitive resin composition can be expected to be reduced in cost compared with the plasma CVD method. However, when a protective film is formed on the electrode for a touch panel, if the thickness of the protective film is large, the step difference between the portion where the film is present and the portion where the film is not present may be conspicuous. Therefore, the protective film is preferably as thin as possible.

However, regarding the level of the thickness of 10 μm or less, there is no example in which the rust resistance of the film formed of the photosensitive resin composition is studied.

In addition, when the protective sensing region is also considered, the transparency of the cured resin film is required in the production of the protective film using the photosensitive resin composition.

An object of the present invention is to provide a protective film for an electrode for a touch panel and a touch panel having the same, wherein the protective film of the electrode for the touch panel has a desired shape and is excellent in transparency, and even It can also have sufficient rust resistance for the film.

In order to solve the above problems, the inventors of the present invention have conducted intensive studies and found that a resin cured film which is formed of a specific photosensitive resin composition and which has been detected by thermal decomposition gas chromatography mass spectrometry has a specific compound. The present invention has been completed in a shape that is excellent in transparency and has sufficient rust resistance even at a thickness of 10 μm or less, and is suitable as a protective film for an electrode for a touch panel.

The present invention provides a protective film for an electrode for a touch panel, which is obtained by curing a predetermined portion of a photosensitive layer containing a photosensitive resin composition, wherein the photosensitive resin composition contains a binder polymer, a photopolymerizable compound, and light. A polymerization initiator; and a protective film of the electrode for a touch panel is detected by thermal decomposition gas chromatography mass spectrometry to detect heptonitrile and benzoic acid.

The protective film for the electrode for a touch panel of the present invention can have a desired shape and is excellent in transparency, and can have sufficient rust preventive property even when the film has a thickness of 10 μm or less.

The reason why the protective film of the electrode for a touch panel of the present invention can exhibit the above effects is as follows. When the thickness of the protective film is small, the corrosive component easily intrudes into the electrode for a touch panel. On the other hand, it is considered that the photosensitive layer containing a component which is a detection source of heptonitrile and benzoic acid has sufficient transparency and pattern formability, and can form a dense hard. The composition of the state. The inventors of the present invention have estimated that the protective film of the electrode for a touch panel can be formed by such a photosensitive layer, and it is possible to have sufficient rust preventive property, transparency, and pattern formation property capable of suppressing the intrusion of a corroding component.

In the protective film for the electrode for a touch panel of the present invention, from the viewpoint of further improving the rust prevention property, the detection peak area of benzoic acid in the thermal decomposition gas chromatography mass spectrometry is preferably relative to the heptonitrile. The peak area is detected and is 1% to 10%.

Further, the protective film of the electrode for a touch panel of the present invention preferably has a minimum visible light transmittance of from 90 nm to 700 nm of 90% or more.

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

Further, from the viewpoint of further improving the rust preventive property, the above-mentioned binder polymer preferably has a hydroxyl value of 50 mg KOH/g or less.

Further, the protective film for the electrode for a touch panel of the present invention preferably has a thickness of 10 μm or less.

Further, the present invention provides a touch panel having the above-described protective film of the present invention.

According to the present invention, it is possible to provide a protective film for an electrode for a touch panel and a touch panel having the same, wherein the protective film of the electrode for the touch panel has a desired shape and is excellent in transparency, and Even a film can have sufficient rust resistance.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the present specification, the term "(meth)acrylic acid" means acrylic acid or methacrylic acid, and the term "(meth)acrylate" means acrylate or a corresponding methacrylate, so-called (meth) propylene. Sulfhydryl refers to acryloyl or methacrylinyl. Further, 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 "step" is not only an independent step, but is also included in the term as long as the intended effect of the step can be achieved even if it cannot be clearly distinguished from other steps. In addition, the numerical range represented by "~" in this specification shows the range in which the numerical value shown before and after "~" is the minimum value and the maximum value respectively.

Further, in the case where the content of each component in the composition is a plurality of substances corresponding to the respective components in the composition, unless otherwise specified, the total amount of the plurality of substances present in the composition is referred to. the amount.

The protective film for the electrode for a touch panel of the present invention is obtained by curing a predetermined portion of the photosensitive layer containing the photosensitive resin composition, and the photosensitive resin composition contains a binder polymer, a photopolymerizable compound, and a photopolymerization initiation. The protective film of the electrode for a touch panel is characterized in that heptonitrile and benzoic acid are detected by thermal decomposition gas chromatography mass spectrometry.

In the specification of the present application, thermal decomposition gas chromatography mass spectrometry of a protective film is performed by gas chromatography mass spectrometry on a gas generated by heating a measurement sample at 140 °C. The heating time of the above-mentioned measurement sample may be in the range of 1 minute to 60 minutes, preferably 30 minutes. Thermal decomposition is shown below Determination conditions of gas chromatography mass spectrometry.

(Measurement conditions for thermal decomposition gas chromatography mass spectrometry)

Measuring device: GC/MS QP-2010 (manufactured by Shimadzu Corporation, product name)

Pipe column: HP-5MS (manufactured by Agilent Technologies, Inc., product name)

Oven Temp: After heating at 40 ° C for 5 minutes, the temperature is raised to 300 ° C at a rate of 15 ° C / min.

Carrier gas: helium, 1.0 mL/min

Interface temperature: 280 ° C

Ion source temperature: 250 ° C

Sample injection amount: 0.1 mL

The detection peak area of the benzoic acid in the thermal decomposition gas chromatography mass spectrometry of the protective film is preferably from 1% to 10%, more preferably from 1% to 9%, and more preferably from 1% to 9%, based on the detection peak area of the heptanonitrile. %~7%, especially good 1%~6%. When the detection peak area of benzoic acid is from 1% to 10%, the effect of the present invention can be more reliably obtained, that is, it has a desired shape, is excellent in transparency, and has sufficient rust resistance even in the case of a film.

Next, a photosensitive element and a photosensitive resin composition which can be used for obtaining a protective film for an 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 for forming a protective film for an electrode for a touch panel of the present invention. The photosensitive element 1 shown in FIG. 1 includes a support film 10, a photosensitive layer 20 provided on the support film 10 and containing the photosensitive resin composition of the present embodiment, and a setting The protective film 30 on the side opposite to the support film 10 of the photosensitive layer 20.

By using the photosensitive element described above, a protective film for the electrode for a touch panel of the present invention can be formed.

The electrode for a touch panel in the present specification refers not only to an electrode located in a sensing region of the touch panel but also to a metal wiring in a fore edge region. The electrode for providing the protective film may be either or both.

A polymer film can be used for the support film 10. The polymer film may, for example, be a film containing polyethylene terephthalate, polycarbonate, polyethylene, polypropylene, polyether oxime or the like.

The thickness of the support film 10 is preferably from 5 μm to 100 μm, more preferably from 10 μm to 70 μm, and further preferably 15 from the viewpoint of ensuring the coating property and suppressing the decrease in the resolution when the active light is irradiated through the support film 10. Mm~40 μm, especially preferably 20 μm~35 μm.

The photosensitive resin composition of the present embodiment constituting the photosensitive layer 20 contains a binder polymer (hereinafter also referred to as component (A)), a photopolymerizable compound (hereinafter also referred to as component (B)), and a photopolymerization initiator ( Hereinafter also referred to as component (C)). The photosensitive resin composition may contain a component which forms a component of heptonitrile and benzoic acid during thermal decomposition of the cured product when the cured product is formed by irradiation with active light. The protective film formed of the photosensitive resin composition containing such a component was detected by the above-described thermal decomposition gas chromatography mass spectrometry to detect heptonitrile and benzoic acid.

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) alkyl (meth)acrylate. Things.

Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and Methyl) hydroxyethyl acrylate.

The above copolymer may further contain another monomer copolymerizable with the above component (a) and/or component (b) in the structural unit.

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

The weight average molecular weight of the binder polymer as the component (A) is preferably from 10,000 to 200,000, more preferably from 15,000 to 150,000, even more preferably from 30,000 to 150,000, particularly preferably from 30,000 to 100,000, in terms of resolution. The best is 40,000~100,000. Further, the measurement conditions of the weight average molecular weight are set to the same measurement conditions as those of the examples of the present specification.

From the viewpoint of easily forming a protective film having a desired shape, the acid value of the binder polymer as the component (A) can be set to 75 mg KOH/g or more, and the controllability of the shape of the protective film and the protective film are both From the viewpoint of rust prevention, the acid value of the binder polymer as the component (A) is preferably 75 mg. KOH/g~200 mg KOH/g, more preferably 75 mg KOH/g to 150 mg KOH/g, and further preferably 75 mg KOH/g to 120 mg KOH/g.

The acid value of the binder polymer as the component (A) can be measured as follows. That is, first, 1 g of the binder polymer as the measurement target of the acid value was accurately weighed. 30 g of acetone was added to the above accurately weighed binder polymer and uniformly dissolved. Then, an appropriate amount of phenolphthalein as an indicator was added to the above solution, and titration was carried out using a 0.1 N aqueous KOH solution. Then, the acid value was calculated by the following formula.

Acid value = 0.1 × Vf × 56.1 / (Wp × I)

In the formula, Vf represents the titer (mL) of the aqueous KOH solution, Wp represents the weight (g) of the measured solution containing the binder polymer, and I represents the ratio of the non-volatile component in the solution containing the binder polymer measured ( quality%).

In the case where the binder polymer is blended in a state of being mixed with a volatile component such as a synthetic solvent or a diluent solvent, it is heated for 1 hour to 4 minutes at a temperature higher than the boiling point of the more volatile component before the accurate weighing. After the removal of the volatile components, the acid value was measured.

The hydroxy value of the binder polymer as the component (A) is preferably 50 mg KOH/g or less, and more preferably 45 mg KOH/g or less, from the viewpoint of further improving the rust preventive property.

The hydroxyl value of the component (A) can be measured as follows.

First, accurately weigh the adhesive polymer 1 as the measurement target of the hydroxyl value. g. 10 mL of a 10% by mass acetic anhydride pyridine solution was added to the adhesive polymer under the above-mentioned accurate weighing and uniformly dissolved, and heated at 100 ° C for 1 hour. After heating, 10 mL of water and 10 mL of pyridine were added and heated at 100 ° C for 10 minutes. Thereafter, the hydroxyl value was measured by neutralization titration with a 0.5 mol/L potassium hydroxide in ethanol solution using an automatic titrator (manufactured by Hiranuma Sangyo Co., Ltd., "COM-1700").

Further, the hydroxyl value can be calculated by the following formula.

Hydroxyl value = (A-B) × f × 28.05 / sample (g) + acid value

Wherein A represents the amount (mL) of a 0.5 mol/L potassium hydroxide ethanol solution used for the blank test, and B represents the amount (mL) of a 0.5 mol/L potassium hydroxide ethanol solution used for titration, and f represents a factor ( Factor).

In the case where the binder polymer is blended in a state of being mixed with a synthetic solvent or a diluent solvent, the above-mentioned synthetic solvent or diluent solvent is heated at a temperature higher by 10 ° C or higher for 1 hour to 4 hours. The hydroxyl value was measured after solvent removal.

As the photopolymerizable compound as the component (B), a photopolymerizable compound having an ethylenically unsaturated group can be used.

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

The monofunctional vinyl monomer is exemplified as a monomer for synthesizing a copolymer which is a preferred example of the component (A). Acrylic acid, alkyl (meth)acrylate and monomers copolymerizable therewith.

Examples of the difunctional vinyl monomer include polyethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, polypropylene glycol di(meth)acrylate, and bisphenol A poly Oxyethylene polyoxypropylene di(meth)acrylate (2,2-bis(4-(methyl)acryloxypolyethoxypolypropyloxyphenyl)propane), bisphenol A diglycidyl ether (meth)acrylate, polycarboxylic acid (such as phthalic anhydride), and a substance having a hydroxyl group and an ethylenically unsaturated group (β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, etc.) Esterified product.

Examples of the polyfunctional vinyl monomer having at least three polymerizable ethylenically unsaturated groups include trimethylolpropane tri(meth)acrylate and tetramethylol methane tri(meth)acrylate. a compound obtained by reacting an α,β-unsaturated saturated carboxylic acid with a polyhydric alcohol such as tetramethylol methane tetra(meth)acrylate, dipentaerythritol penta (meth) acrylate or dipentaerythritol hexa(meth) acrylate a compound obtained by adding an α,β-unsaturated carboxylic acid to a glycidyl group-containing compound such as trimethylolpropane triglycidyl ether triacrylate or the like.

Among these, a polyfunctional vinyl monomer having at least 3 polymerizable ethylenically unsaturated groups is preferred. Further, from the viewpoint of suppressing the electrode corrosion and easiness of development, it is preferred to contain at least one selected from the group consisting of a (meth) acrylate compound having a skeleton derived from pentaerythritol and having dipentaerythritol derived therefrom. a (meth) acrylate compound of a skeleton and a (meth) acrylate compound having a skeleton derived from trimethylolpropane, more preferably at least one selected from the group consisting of a skeleton derived from dipentaerythritol (meth) acrylate compound and A (meth) acrylate compound having a skeleton derived from trimethylolpropane.

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

Further, the above-mentioned (meth) acrylate compound having a skeleton derived from trimethylolpropane means an esterified product of trimethylolpropane and (meth)acrylic acid, and the esterified product also contains an alkylene oxide. Base modified compound. The esterified product preferably has a number of ester bonds in one molecule of 3, and may be a compound in which the number of ester bonds is 1 to 2.

These compounds may be used alone or in combination of two or more.

In the case where a monomer having at least three polymerizable ethylenically unsaturated groups in the molecule is used in combination with a monofunctional vinyl monomer or a difunctional vinyl monomer, the use ratio is not particularly limited, and light is obtained. From the viewpoint of the curability of the curable property and the corrosion resistance of the electrode, 100 parts by mass of the total amount of the photopolymerizable compound contained in the photosensitive resin composition, the monomer having at least three polymerizable ethylenically unsaturated groups in the molecule The proportion of the body 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 component (A) and the component (B) in the photosensitive resin composition of the present embodiment is preferably 35 (A), respectively, based on 100 parts by mass of the total of the components (A) and (B). Mass parts ~85 parts by mass, The component (B) is 15 parts by mass to 65 parts by mass, more preferably 40 parts by mass to 80 parts by mass of the component (A), and 20 parts by mass to 60 parts by mass of the component (B), and further preferably the component (A) is 50 parts by mass to 70 parts by mass, and (B) component is 30 parts by mass to 50 parts by mass, particularly preferably (A) component is 55 parts by mass to 65 parts by mass, and (B) component is 35 parts by mass to 45 parts by mass. In particular, the content of the component (A) and the component (B) is preferably (A) in terms of 100 parts by mass of the total of the components (A) and (B), in terms of maintaining the transparency and the pattern. It is 35 parts by mass or more, more preferably 40 parts by mass or more, further 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) within the above range, the coating property or the film property in the photosensitive element can be sufficiently ensured, and sufficient sensitivity can be obtained, and photocurability and development can be sufficiently ensured. Sexual and electrode corrosion inhibition.

The photosensitive resin composition of the present embodiment preferably contains an oxime ester compound as a photopolymerization initiator which is a component (C). By containing an oxime ester compound, a resin cured film pattern which is formed into a film having a thickness of 10 μm or less but which is formed with sufficient resolution can be formed on the substrate. Further, a resin cured film pattern excellent in transparency can also be formed.

The oxime ester compound is exemplified by the compound represented by the following formula (C-1).

[Chemical 1]

In the above 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 effects of the present invention are not impaired, a substituent may be added to the aromatic ring in the above formula (C-1).

In the above 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, more preferably an alkyl group having 4 to 8 carbon atoms or a carbon number of 4 to 8. 10 cycloalkyl groups.

The compound represented by the above formula (C-1) may, for example, be (1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzylidenefluorene)] or the like. ,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzhydrylhydrazine)] can be manufactured as IRGACURE OXE 01 (BASF) , the product name) and get.

Among the above formula (C-1), particularly preferred is 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzylidenefluorene)]. In this case, 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzylidenefluorene)] is a protective film formed of the resin composition of the present embodiment. When subjected to thermal decomposition gas chromatography mass spectrometry, it was detected as heptonitrile and benzoic acid. Further, in this case, the detection peak area of benzoic acid in the thermal decomposition gas chromatography mass spectrometry of the obtained protective film is preferably from 1% to 10% with respect to the detection peak area of heptonitrile, and more preferably Good is 1% to 9%, and then preferably 1% to 7%, especially preferably 1% to 6%. When the detection peak area of benzoic acid is from 1% to 10%, the effect of the present invention can be more reliably obtained, that is, it has a desired shape, is excellent in transparency, and has sufficient rust resistance even in the case of a film.

The component (C) may 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, and 2-benzyl-2-dimethylamino group. Aromatic ketones such as 1-(4-morpholinylphenyl)-butanone-1, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-acetone-1 ; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether; benzoin compounds such as benzoin, methyl benzoin, ethyl benzoin; benzyl derivatives such as benzyl dimethyl ketal; 9-phenyl acridine, 1 , acridine derivative such as 7-bis(9,9'-acridinyl)heptanone; N-phenylglycine, N-phenylglycine derivative; coumarin compound; oxazole compound . Further, a thioxanthone-based compound may be combined with a tertiary amine compound as in the combination of diethylthioxanthone and dimethylaminobenzoic acid.

The content of the photopolymerization initiator as the component (C) is preferably from 0.1 part by mass to 20 parts by mass, more preferably from 1 part by mass to 10 parts by mass per 100 parts by mass of the total of the component (A) and the component (B). The mass part is further preferably 2 parts by mass to 5 parts by mass.

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

In view of further improving the rust preventive property of the protective film, the photosensitive resin composition of the present embodiment preferably 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 amine group, or a tetrazole compound having an amine group (hereinafter also referred to as a component (D)). Examples of the triazole compound having a mercapto group include 3-mercapto-triazole (manufactured by Wako Pure Chemical Industries, Ltd., trade name: 3MT). Further, examples of the thiadiazole compound having a mercapto group include 2-amino-5-mercapto-1,3,4-thiadiazole (manufactured by Wako Pure Chemical Industries, Ltd., trade name: ATT).

The above triazole compound having an amine group may be exemplified by an amine group substituted with benzotriazole, 1H-benzotriazole-1-acetonitrile, benzotriazole-5-carboxylic acid, 1H-benzotriazole-1- A compound obtained by adding a compound such as methanol or carboxybenzotriazole to an amide group-containing triazole compound such as 3-mercaptotriazole or 5-mercaptotriazole.

Among these, from the viewpoint of further reducing the development residue, a compound containing an amine group substituted on a mercapto group-containing triazole compound is preferred. Specifically, for example, 3-amino-5-mercaptotriazole (manufactured by BASF Co., Ltd., trade name: AMT) can be mentioned.

The tetrazole compound having an amine group may, for example, be a compound represented by the following formula (D-1).

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

The alkyl group may, for example, be a methyl group, an ethyl group or a propyl group.

Among the tetrazole compounds represented by the above formula (D-1), 5-amino-1H-tetrazole, 1-methyl-5-amino-tetrazole, 1-methyl-5-fluorenyl group are preferred. -1H-tetrazole or 1-carboxymethyl-5-amino-tetrazole.

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

Among these, 5-amino-1H-tetrazole and 1-methyl-5-fluorenyl are particularly preferable from the viewpoints of the suppression of electrode corrosion, the adhesion to the metal electrode, the easiness of development, and the transparency. -1H-tetrazole.

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

In the case where the surface of the electrode on which the protective film is provided has a metal such as copper, a copper alloy or a nickel alloy, the photosensitive resin composition preferably further contains a tetrazole having an amine group from the viewpoint of further improving the rust preventive property. A compound obtained by substituting a compound or an amine group on a triazole compound containing a mercapto group. In this case, the development residue can be reduced, and the protective film can be easily formed in a good pattern. The reason for this is considered to be that it exhibits an appropriate adhesion of the surface.

In the case of a compound containing a tetrazole compound having an amine group or an amine group substituted on a triazole compound containing a mercapto group, the above effects can be obtained, so that the photosensitive resin composition of the present embodiment and the photosensitive member are suitable. Forming a protective film for protecting a metal layer formed of copper or the like to improve conductivity The protective film of the electrode in the fore edge area of the touch panel.

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

Further, when a protective film is provided on a portion of the ITO electrode of the touch panel, for example, a protective film is not formed in the sensing region, and an ITO electrode and an ITO electrode are formed on the front edge region. When a protective film is provided on a portion of the metal layer such as copper, the photosensitive layer may be provided as a whole, and then exposed and developed to remove unnecessary portions. In this case, the photosensitive layer is required to have characteristics of sufficient adhesion to the electrode to be protected, and good developability is required to prevent development residue from being generated in an unnecessary portion. The photosensitive resin composition of the present invention preferably contains a phosphate ester containing a photopolymerizable unsaturated bond (hereinafter also referred to as a component (E)) from the viewpoint of the adhesion and the developability in such a case.

The phosphate ester-containing unsaturated bond-containing phosphate ester as the component (E) sufficiently ensures the rust-preventing property of the formed protective film and has a high level of adhesion to the ITO electrode and developability. Preferably, the phosphate ester is a compound having the following structure. This compound can be obtained as a commercial item such as PM21 (manufactured by Nippon Kayaku Co., Ltd.).

[Chemical 3]

In addition, the photosensitive resin composition of the present embodiment may be contained in an amount of from 0.01 part by mass to 20 parts by mass, based on 100 parts by mass of the total of the components (A) and (B), as needed. The following components: an adhesion imparting agent such as a decane coupling agent, a leveling agent, a plasticizer, a filler, an antifoaming agent, a flame retardant, a stabilizer, an antioxidant, a perfume, a thermal crosslinking agent, a polymerization inhibitor, and the like. These may be used alone or in combination of two or more.

Here, the visible light transmittance of the photosensitive resin composition can be obtained as follows. First, a coating liquid containing a photosensitive resin composition is applied to the support film so as to have a thickness of 10 μm or less after drying, and dried to form a photosensitive resin composition layer (photosensitive layer). Then, lamination was carried out on the glass substrate in such a manner that the photosensitive resin composition layer (photosensitive layer) was in contact with the glass substrate using a laminator. In this manner, a sample for measurement in which a photosensitive resin composition layer and a support film were laminated on a glass substrate was obtained. Then, the obtained measurement sample was irradiated with ultraviolet light to photo-curing the photosensitive resin composition layer, and then the transmittance in the measurement wavelength range of 400 nm to 700 nm was measured using an ultraviolet-visible spectrophotometer.

In addition, the above-mentioned preferable transmittance means the minimum value of the transmittance in the said wavelength range.

If the light in the normal visible light wavelength range, that is, the transmittance in the wavelength range of 400 nm to 700 nm is 90% or more, for example, the touch protection is used. a transparent electrode of a sensing region of a panel (touch sensor) or a metal layer for protecting a front edge region of a touch panel (touch sensor) (for example, a copper layer is formed on the ITO electrode) When the protective film is visible from the end of the sensing region, the image display quality, chromaticity, and brightness reduction in the sensing region can be sufficiently suppressed.

The photosensitive resin composition of this embodiment can be used for forming a photosensitive layer on a substrate. For example, a coating liquid obtained by uniformly dissolving or dispersing a photosensitive resin composition in a solvent can be prepared and applied onto a substrate to form a coating film, and the solvent is removed by drying, thereby forming a photosensitive film. Floor.

The solvent may be a ketone, an aromatic hydrocarbon, an alcohol, a glycol ether, a glycol alkyl ether, a glycol alkyl ether acetate, an ester, or the like in terms of solubility of each component, easiness of formation of a coating film, and the like. Diethylene glycol. These solvents may be used singly or in the form of a mixed solvent containing two or more solvents.

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 diethylene glycol are preferably used. Ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and the like.

The photosensitive resin composition of the present embodiment is preferably used as a photosensitive film as in the photosensitive element 1. By laminating a photosensitive film on a substrate having an electrode for a touch panel, the roll-to-roll process can be easily realized, the solvent drying step and the like can be shortened, and the manufacturing process can be shortened or the cost can be greatly reduced. .

The photosensitive layer 20 of the photosensitive element 1 can be formed by preparing a coating liquid containing the photosensitive resin composition of the present embodiment, applying it to the support film 10, and drying it. The coating liquid can be obtained by: Each component constituting the photosensitive resin composition of the present embodiment described above is uniformly dissolved or dispersed in a solvent.

The solvent is not particularly limited, and a known solvent can be used, and examples thereof include acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, methanol, ethanol, propanol, butanol, methylene glycol, and B. 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. These solvents may be used singly or in the form of a mixed solvent containing two or more solvents.

Examples of the coating method include a knife coating method, a Meyer bar coating method, a roll coating method, a screen coating method, a spin coating method, an inkjet coating method, and a spray coating method. , dip coating method, gravure coating method, curtain coating method, die coating method.

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

The thickness of the photosensitive layer is such that the thickness of the photosensitive layer is minimized in order to exhibit the effect of sufficiently protecting the electrode and the surface of the touch panel (touch sensor) caused by the partial formation of the electrode protective film. The thickness after drying is preferably 1 μm or more and 9 μm or less, more preferably 1 μm or more and 8 μm or less, further preferably 2 μm or more and 8 μm or less, and particularly preferably 3 μm or more and 8 μm or less. .

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

When the photosensitive element is formed into a roll shape in the case of the viscosity of the photosensitive layer 20, the photosensitive resin composition is prevented from oozing out from the end surface of the photosensitive element 1 during one month or more, and the photosensitive light is prevented from being cut. The viscosity of the photosensitive layer 20 at a temperature of 30 ° C is preferably 15 mPa in terms of poor exposure or development residue when the active light ray is adhered to the substrate due to adhesion of the photosensitive resin composition to the substrate. s~100 mPa. s, more preferably 20 mPa. s~90 mPa. s, and thus preferably 25 mPa. s~80 mPa. s.

In addition, the viscosity is a value of a circular film having a diameter of 7 mm and a thickness of 2 mm formed of a photosensitive resin composition as a sample for measurement, and is 30 ° C in the thickness direction of the sample. When a load of 1.96 × 10 ^-2 N was applied at 80 ° C, the rate of change in thickness was measured, and it was assumed to be a Newtonian fluid according to the rate of change, and the value was converted into a viscosity.

Examples of the protective film 30 (cover film) include polyethylene, polypropylene, polyethylene terephthalate, polycarbonate, polyethylene-vinyl acetate copolymer, and polyethylene-vinyl acetate copolymer (polyethylene). -vinyl acetate copolymer) A film such as a laminate film of polyethylene.

The thickness of the protective film 30 is preferably about 5 μm to 100 μm, and is preferably 70 μm or less, more preferably 60 μm or less, and even more preferably 50 μm or less from the viewpoint of being wound into a roll and stored. It is 40 μm or less.

The photosensitive element 1 can be wound into a roll shape and stored or used.

In the present embodiment, the coating liquid containing the photosensitive resin composition and the solvent of the present embodiment described above may be applied onto a substrate having an electrode for a touch panel, dried, and provided with a photosensitive resin composition. The photosensitive layer 20 of the object. In the case of this use, it is also preferred that the photosensitive layer satisfies the above film. Thick, visible light transmittance.

Next, a method of forming a protective film for the electrode for a touch panel of the present invention will be described. FIG. 2 is a schematic cross-sectional view showing an example of a method of forming a protective film for an electrode for a touch panel of the present invention.

The method for forming a protective film for an electrode for a touch panel of the present embodiment includes the steps of: providing a first step on the substrate 100 having the touch panel electrode 110 and the touch panel electrode 120; The photosensitive layer 20 of the photosensitive resin composition of the present embodiment; the second step of curing the predetermined portion of the photosensitive layer 20 by irradiation with active light containing ultraviolet rays; and the third step of irradiating the active light with a portion other than the predetermined portion The photosensitive layer is removed to form a protective film 22 which covers a part or all of the electrode and contains a cured film pattern of the photosensitive resin composition. In this way, a touch panel (touch sensor) 200 with a protective film as a touch input sheet can be obtained.

The substrate 100 used in the present embodiment is a substrate such as a glass plate, a plastic plate, or a ceramic plate which is generally used as a touch panel (touch sensor). An electrode for a touch panel is provided on the substrate (the electrode for the touch panel is a target for forming a resin cured film as a protective film). Examples of the electrode include an electrode of ITO, Cu, Al, Mo, or the like, and a thin film transistor (TFT). Further, an insulating layer may be provided between the substrate and the electrode on the substrate.

The substrate 100 having the touch panel electrode 110 and the touch panel electrode 120 shown in FIG. 2 can be obtained, for example, in the following order. On the substrate 100 such as a PET film, a metal film is formed by sputtering in the order of ITO or Cu. Thereafter, a photosensitive film for etching is attached to the metal film to form a desired resist pattern, and the unnecessary Cu is removed by an etching solution such as an aqueous solution of ferric chloride, and then the resist pattern is removed and removed.

In the first step, after the protective film 30 of the photosensitive element 1 of the present embodiment is removed, the photosensitive element is heated, and the touch panel electrode 110 and the touch panel are provided on the substrate 100. The photosensitive layer 20 is pressure-bonded to the surface of the electrode 120, thereby transferring and laminating (see FIG. 2(a)).

The crimping mechanism can be exemplified by a crimping roller. The crimping roller may also have a heating mechanism to allow for thermocompression bonding.

The heating temperature in the case of heating and pressure bonding is sufficient to ensure the adhesion between the photosensitive layer 20 and the substrate 100, and the adhesion between the photosensitive layer 20 and the touch panel electrode 110 and the touch panel electrode 120, and The constituent component of the photosensitive layer 20 is less likely to be thermally hardened or thermally decomposed, and the heating temperature is preferably set to 10 ° C to 160 ° C, more preferably 20 ° C to 150 ° C, and even more preferably 30 ° C to 150 ° C.

Further, from the viewpoint of sufficiently ensuring the adhesion between the photosensitive layer 20 and the substrate 100 and suppressing the deformation of the substrate 100 with respect to the pressure contact pressure at the time of heating and pressure bonding, the pressure of the pressure is preferably set by a line gauge. It is 50 N/m to 1×10 ⁵ N/m, more preferably set to 2.5×10 ² N/m to 5×10 ⁴ N/m, and is preferably set to 5×10 ² N/m to 4×. 10 ⁴ N/m.

When the photosensitive element 1 is heated as described above, it is not necessary to preheat the substrate, but in order to further improve the adhesion between the photosensitive layer 20 and the substrate 100, it is preferred to preheat the substrate 100. . The preheating temperature at this time is preferably set to 30 ° C to 150 ° C.

In the method of the present embodiment, a coating liquid containing the photosensitive resin composition and the solvent of the present embodiment may be prepared instead of using a photosensitive element, and the electrode for a touch panel applied to the substrate 100 may be provided. 110 and the surface of the touch panel electrode 120 are dried to form the photosensitive layer 20.

The photosensitive layer 20 is preferably a condition that satisfies the above film thickness and visible light transmittance.

In the second step described above, the predetermined portion of the photosensitive layer 20 is irradiated with the active light ray L in a pattern via the mask 130 (see FIG. 2(b)).

When the active light is irradiated, when the support film 10 on the photosensitive layer 20 is transparent, the active light may be directly irradiated. When the support film 10 on the photosensitive layer 20 is opaque, the support film 10 is removed and the irradiation activity is performed. Light. In terms of protecting the photosensitive layer 20, it is preferable to use a transparent polymer film as the support film 10, and to keep the polymer film remaining, the active light is irradiated through the polymer film.

A known active light source can be used as the light source for illuminating the active light of the active light L, and examples thereof include a carbon arc lamp, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, and the like, and there is no particular limitation as long as it is a light source that efficiently emits ultraviolet rays. .

The irradiation amount of the active light ray L at this time is usually 1 × 10 ² J/m ² to 1 × 10 ⁴ J/m ² , and may be accompanied by heating during irradiation. When the amount of the active light irradiation is less than 1 × 10 ² J/m ² , the effect of photocuring tends to be insufficient, and if the amount of the active light irradiation exceeds 1 × 10 ⁴ J/m ² , the photosensitive layer 20 is present. The tendency to change color.

In the third step, the photosensitive layer irradiated with the active light is developed by the developer, and the portion where the active light is not irradiated (ie, the photosensitive layer) In addition to the predetermined portion, the protective film 22 is formed, and the protective film 22 covers a part or the whole of the electrode, and has a thickness of 10 μm or less and includes a cured film pattern of the photosensitive resin composition of the present embodiment (see FIG. 2(c)). . The formed protective film 22 may have a predetermined pattern.

Further, when the support film 10 is laminated on the photosensitive layer 20 after the irradiation of the active light, the support film 10 is removed, and development of the portion where the active light is not irradiated is removed by the developer.

The developing method is a known developing solution such as an alkaline aqueous solution, an aqueous developing solution, or an organic solvent, and is developed by a known method such as spraying, spraying, shaking, scouring, brushing, or scraping, and is unnecessary. As a method of partial removal, a method of using an aqueous alkaline solution is exemplified as a preferred development method from the viewpoint of environment and safety.

Examples of the base of the alkaline aqueous solution include alkali hydroxide (such as lithium, sodium or potassium hydroxide), alkali carbonate (such as lithium, sodium or potassium carbonate or bicarbonate), and alkali metal phosphate (potassium phosphate, Sodium phosphate or the like, alkali metal pyrophosphate (such as sodium pyrophosphate or potassium pyrophosphate), tetramethylammonium hydroxide or triethanolamine, and the like, and tetramethylammonium hydroxide or the like is preferred.

Further, an aqueous solution of sodium carbonate can be preferably used. For example, a thin solution (0.5% by mass to 5% by mass of an aqueous solution) of sodium carbonate at 20 ° C to 50 ° C can be preferably used.

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

Further, a surfactant, an antifoaming agent, a small amount of an organic solvent for promoting development, and the like may be mixed in the alkaline aqueous solution.

Further, after development, an alkali solution of the alkaline aqueous solution remaining in the photosensitive layer 20 after photocuring can be carried out by a known method such as spraying, shaking, immersing, brushing or scratching using an organic acid, an inorganic acid or the like. Acid treatment (neutralization treatment).

Further, the water washing step may be performed after the acid treatment (neutralization treatment).

After development, the cured film pattern may be further hardened by irradiation with active light (for example, 5 × 10 ³ J/m ² to 2 × 10 ⁴ J/m ² ) as needed. In addition, the photosensitive resin composition of the present embodiment exhibits excellent adhesion to metal even without a heating step after development, but may be performed instead of irradiation with active light after development or irradiation with active light, if necessary. Heat treatment (80 ° C ~ 160 ° C).

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

As an example of the detection of heptonitrile and benzoic acid by thermal decomposition gas chromatography mass spectrometry of a protective film, as described above, the photosensitive resin composition constituting the photosensitive layer contains 1,2-octanedione. 1-[4-(phenylthio)-,2-(O-benzhydrylhydrazine)] is the case of the component (C).

Next, an example of a use portion of the protective film of the present invention will be described with reference to FIGS. 3, 4 and 5. 3 is a schematic plan view showing an example of a capacitive touch panel. The touch panel shown in FIG. 3 has a touch screen 102 for detecting a touch position coordinate on a single surface of the transparent substrate 101. The substrate 101 is provided with static electricity for detecting an area of the touch screen 102. The transparent electrode 103 and the transparent electrode 104 whose capacitance changes. The transparent electrode 103 and the transparent electrode 304 respectively detect the X coordinate of the touch position and Y coordinates.

The transparent substrate 101 is provided with a protruding wiring 105 for transmitting a detection signal of the touch position from the transparent electrode 103 and the transparent electrode 104 to an external circuit. Further, the extension wiring 105, the transparent electrode 103, and the transparent electrode 104 are connected by a connection electrode 106 provided on the transparent electrode 103 and the transparent electrode 104. Further, a connection terminal 107 connected to an external circuit is provided at an end portion of the extension wiring 105 opposite to the connection portion with the transparent electrode 103 and the transparent electrode 104. The photosensitive resin composition of the present invention can be preferably used for forming the protective film 122 of the extension wiring 105, the connection electrode 106, and the connection terminal 107. At this time, the electrodes located in the sensing area can also be protected at the same time. In FIG. 3, the extension wiring 105, the connection electrode 106, a part of the electrode of the sensing region, and a part of the connection terminal 107 are protected by the protective film 122, but the portion where the protective film is provided may be appropriately changed. For example, the protective film 123 may be provided to protect the entire touch screen 102 as shown in FIG.

The cross-sectional structure of the connection portion between the transparent electrode and the extension wiring in the touch panel shown in FIG. 3 will be described with reference to FIG. 5. Fig. 5 is a partial cross-sectional view taken along 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 extension wiring 105. As shown in FIG. 5( a ), the transparent electrode 104 and the extension wiring 105 are electrically connected via the connection electrode 106 . As shown in FIG. 5(a), a part of the transparent electrode 104 and all of the extension wiring 105 and the connection electrode 106 are covered by the protective film 122. Similarly, the transparent electrode 103 and the extension wiring 105 are electrically connected via the connection electrode 106. Furthermore, as shown in FIG. 5(b), the transparent electrode 104 is extended The wiring 105 can also be directly electrically connected. The photosensitive resin composition and the photosensitive element of the above-described embodiment are suitably used for forming a resin cured film pattern as a protective film of the above-mentioned structural portion.

A method of manufacturing the touch panel of the present embodiment will be described. First, a transparent electrode (X position coordinate) 103 is formed on the transparent electrode 101 provided on the substrate 100. Then, a transparent electrode (Y position coordinate) 104 is formed. For the formation of the transparent electrode 103 and the transparent electrode 104, a method of etching a transparent electrode layer formed on the substrate 100 or the like can be used.

Then, on the surface of the transparent substrate 101, a protruding wiring 105 for connection to an external circuit, and a connection electrode 106 for connecting the protruding wiring to the transparent electrode 103 and the transparent electrode 104 are formed. The extension wiring 105 and the connection electrode 106 may be formed after the transparent electrode 103 and the transparent electrode 104 are formed, or may be formed simultaneously when each transparent electrode is formed. The formation of the extension wiring 105 and the connection electrode 106 can be performed by etching or the like after metal sputtering. The extension wiring 105 can be formed, for example, by using a conductive paste material containing scaly silver, while forming the connection electrode 106 by a screen printing method. Then, a connection terminal 107 for connecting the extension wiring 105 to an external circuit is formed.

The photosensitive element 1 of the present embodiment is pressure-bonded so as to cover the transparent electrode 103 and the transparent electrode 104, the extension wiring 105, the connection electrode 106, and the connection terminal 107 formed by the above steps, and a photosensitive layer is provided on the electrode. 20. Then, the transferred photosensitive layer 20 is irradiated with the active light L in a pattern through a mask in a desired shape. After the active light ray L is irradiated, development is performed to remove the predetermined portion of the photosensitive layer 20, thereby forming a protective film 122 containing a cured portion of a predetermined portion of the photosensitive layer 20. So can be made A touch panel having a protective film 122 is formed.

Example

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

[Production of Adhesive Polymer Solution (A1)]

(1) shown in Table 1 was placed in a flask equipped with a stirrer, a reflux condenser, an inert gas inlet, and a thermometer, and the temperature was raised to 80 ° C in a nitrogen atmosphere while maintaining the reaction temperature at 80 ° C ± 2 ° C. (2) shown in Table 1 was uniformly added dropwise over 4 hours. After the dropwise addition of (2), stirring was continued at 80 ° C ± 2 ° C for 6 hours to obtain a solution of a 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).

Further, the weight average molecular weight (Mw) is derived by measuring by Gel Permeation Chromatography (GPC) and using a calibration curve of standard polystyrene. Count. The conditions of GPC are shown below.

GPC condition

Pump: Hitachi L-6000 (manufactured by Hitachi, Ltd., product name)

Column: Gelpack GL-R420, Gelpack GL-R430, Gelpack GL-R440 (above, manufactured by Hitachi Chemical Co., Ltd., product name)

Dissolution: tetrahydrofuran

Measuring temperature: 40 ° C

Flow rate: 2.05 mL/min

Detector: Hitachi L-3300 refractive index detector (Refractive Index, RI) (manufactured by Hitachi, Ltd., product name)

[Method for measuring acid value]

In addition, the acid value was measured as follows. First, the adhesive polymer solution was heated at 130 ° C for 1 hour to remove volatile components to obtain a solid component. Then, after accurately weighing 1 g of the polymer to be measured for the acid value, 30 g of acetone was added to the polymer and uniformly dissolved. Then, an appropriate amount of phenolphthalein as an indicator was added to the solution, and titration was carried out using a 0.1 N aqueous KOH solution. Then, the acid value was calculated by the following formula.

Acid value = 0.1 × Vf × 56.1 / (Wp × I)

In the formula, Vf represents the titer (mL) of the KOH aqueous solution, Wp represents the weight (g) of the measured resin solution, and I represents the ratio (% by mass) of the nonvolatile component in the measured resin solution.

[Method for 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 the volatile component to obtain a solid component. Then, after accurately weighing 1 g of the polymer to be measured for the hydroxyl value, the accurately weighed photosensitive resin composition was placed in an Erlenmeyer flask, and 10 mL of a 10% by mass acetic anhydride pyridine solution was added thereto and uniformly dissolved. Heat at 100 ° C for 1 hour. After heating, 10 mL of water and 10 mL of pyridine were added and heated at 100 ° C for 10 minutes, and then an automatic titrator ("COM-1700", manufactured by Hiranuma Satoshi Co., Ltd.) was used, with 0.5 mol/L of potassium hydroxide. The ethanol solution was subjected to neutralization titration. Then, the hydroxyl value was calculated by the following formula.

Hydroxyl value = (A - B) × f × 28.05 / sample (g) + acid value.

In the formula, A represents the amount (mL) of a 0.5 mol/L potassium hydroxide ethanol solution used for the blank test, and B represents the amount (mL) of a 0.5 mol/L potassium hydroxide ethanol solution used for titration, and f represents a factor.

(Examples 1 to 8 and Comparative Examples 1 to 8) [Production 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 liquid containing a photosensitive resin composition for forming a protective film.

[Production of photosensitive element]

A polyethylene terephthalate film having a thickness of 50 μm was used as a support film, and the coating liquid containing the photosensitive resin composition prepared above was uniformly applied to a support film using a comma coater. The solvent is removed by drying with a hot air convection dryer at 100 ° C for 3 minutes. A photosensitive layer (photosensitive resin composition layer) containing a photosensitive resin composition. The resulting photosensitive layer had a thickness of 5 μm.

Then, a polyethylene film having a thickness of 25 μm was further bonded to the obtained photosensitive layer as a cover film to prepare a photosensitive member for forming a protective film.

[Measurement of Transmittance of Protective Film]

A polyethylene film which is a cover film of the obtained photosensitive element is peeled off from the glass substrate having a thickness of 1 mm, and the photosensitive layer is brought into contact with the glass substrate, and a laminator (manufactured by Hitachi Chemical Co., Ltd., trade name HLM) is used. -3000 type) The roller temperature is 120 ° C, the substrate feed speed is 1 m / min, and the crimp pressure (cylinder pressure) is 4 × 10 ⁵ Pa (due to the use of thickness 1 mm, length 10 cm × width 10 cm) The substrate was laminated under the conditions of a line pressure of 9.8 × 10 ³ N/m at this time, and a laminate in which a photosensitive layer and a support film were laminated on a glass substrate was produced.

Then, using a parallel light exposure machine (manufactured by ORC), EXM1201, the photosensitive layer of the obtained laminated body was exposed to an amount of 5 × 10 ² J/m ² from the side of the photosensitive layer (i-ray ( The measured value at a wavelength of 365 nm) was irradiated with ultraviolet rays, and the support film was removed, and allowed to stand in a box dryer (manufactured by Mitsubishi Electric Corporation, model: NV50-CA) heated to 140 ° C for 30 minutes to obtain A sample for measuring the transmittance of a protective film having a thickness of 5 μm.

Then, an ultraviolet-visible spectrophotometer (U-3310) manufactured by Hitachi High-technologies Co., Ltd. was used to measure the visible light transmittance in the measurement wavelength range of 400 nm to 700 nm. Calculate the minimum value. The measurement results are shown in Tables 4 and 5.

[Salt Spray Test of Protective Film (Artificial Sweat Resistance Evaluation Test)]

The polyethylene film of the obtained photosensitive element is peeled off, and a laminator is used to contact the sputtered copper on the polyimide layer with a sputtered copper (manufactured by Toray Film Processing Co., Ltd.). (Manufactured by Hitachi Chemical Co., Ltd., trade name HLM-3000) at a roll temperature of 120 ° C, a substrate feed rate of 1 m/min, and a crimping pressure (cylinder pressure) of 4 × 10 ⁵ Pa (due to the thickness used) It is a substrate of 1 mm, a length of 10 cm, and a width of 10 cm, so that the line pressure at this time is 9.8×10 ³ N/m), and lamination is performed on the sputtered copper layer with a layer of a photosensitive layer and a support film. body.

Then, using a parallel light exposure machine (manufactured by ORC Co., Ltd., EXM1201), the photosensitive layer of the obtained laminated body was exposed to an amount of 5 × 10 ² J/m ² from the photosensitive side (i-ray (wavelength) After irradiating ultraviolet rays to the measured value at 365 nm), the support film was removed, and further, the exposure amount (i-ray (wavelength: 365 nm)) was irradiated from the side of the photosensitive layer at an exposure amount of 1 × 10 ⁴ J/m ² . Ultraviolet rays were allowed to stand in a box dryer (manufactured by Mitsubishi Electric Corporation, model: NV50-CA) heated to 140 ° C for 30 minutes. A sample for artificial sweat resistance evaluation in which a protective film having a thickness of 5.0 μm was formed was obtained.

Then, referring to the Japanese Industrial Standards (JIS) standard (Z 2371), the test was carried out in a test tank using a salt spray tester (Suga tester (STP-90V2)). In the test tank temperature of 35 ° C, a concentration of 50 g / L of saline (pH = 6.7) was sprayed at a spray rate of 1.5 mL / h for 48 hours. After the spraying is completed, the salt water is wiped off, and the surface of the evaluation sample is observed. State, evaluated according to the following ratings. The measurement results are shown in Tables 4 and 5.

A: The surface of the protective film is completely unchanged.

B: Very few traces were visible on the surface of the protective film, but the copper did not change.

C: Traces were visible on the surface of the protective film, but copper did not change.

D: There are marks on the surface of the protective film, and the copper is discolored.

[Measurement of generated gas after heating at 140 ° C for 30 minutes (thermal decomposition gas chromatography mass spectrometry)]

The polyethylene film of the obtained photosensitive member was peeled off while being coated with a photosensitive layer on a polytetrafluoroethylene sheet (manufactured by Nitto Denko Co., Ltd., product name: Nitoflon film No. 900U). A method of using a laminating machine (manufactured by Hitachi Chemical Co., Ltd., trade name HLM-3000) at a roll temperature of 120 ° C, a substrate feed rate of 1 m/min, and a crimping pressure (cylinder) The pressure was carried out under the conditions of 4 × 10 ⁵ Pa.

Then, using a parallel light exposure machine (manufactured by ORC Co., Ltd., EXM1201), the photosensitive layer of the obtained laminated body was exposed to an amount of 5 × 10 ² J/m ² from the photosensitive side (i-ray (wavelength) After irradiating ultraviolet rays to the measured value at 365 nm), the support film was removed, and further, the exposure amount (i-ray (wavelength: 365 nm)) was irradiated from the side of the photosensitive layer at an exposure amount of 1 × 10 ⁴ J/m ² . Ultraviolet light was used to obtain a measurement sample for thermal decomposition gas chromatography mass spectrometry.

Using a Tekmar 7000HT headspace sampler, the measured sample will be heated at 140 ° C for 30 minutes and will be produced. The gas was introduced into Gas Chromatograph/Mass Spectrometry (GC/MS) (manufactured by Shimadzu Corporation, model: GC/MS QP-2010, carrier gas: helium, 1.0 mL/min, column: HP -5MS, oven (Oven): After heating at 40 ° C for 5 minutes, the temperature is raised 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) Analyze. The measurement results are shown in Tables 4 and 5. Further, a gas phase chromatogram in the case of performing thermal decomposition gas chromatography mass spectrometry on the protective film obtained in Example 6 is shown in Fig. 6 . In Fig. 6, A represents a detection peak of benzoic acid, and B represents a detection peak of heptonitrile.

The symbols of the components of Tables 2 and 3 indicate the following meanings.

(A) component

(A1): a propylene glycol monomethyl ether/toluene solution of a copolymer having a monomer ratio (methacrylic acid/methyl methacrylate/ethyl acrylate = 12/58/30 (mass ratio)), and a weight average molecular weight of 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 Industry Co., Ltd.)

DPHA: dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.)

TMPTA: Trimethylolpropane triacrylate (manufactured by Nippon Kayaku Co., Ltd.)

UX-3204: Acrylic urethane containing hydroxyethyl acrylate, polyester polyol and hexamethylene diisocyanate in raw material composition (manufactured by Nippon Kayaku Co., Ltd.)

PET-30: pentaerythritol triacrylate (manufactured by Nippon Kayaku Co., Ltd.)

(C) component

IRGACURE OXE 01:1, 2-octanedione, 1-[(4-phenylthio)-, 2-(O-benzylidene fluorene)] (Manufactured by BASF) )

IRGACURE 184: 1-Hydroxy-cyclohexyl-phenyl-ketone (Manufactured by BASF)

IRGACURE 651: 2,2-Dimethoxy-1,2-diphenylethane-1-one (Manufactured by BASF)

IRGACURE 369: 2-Benzyl-2-dimethylamino-1-(morpholinylphenyl)-butanone-1 (Manufactured by BASF)

IRGACURE 907: 2-Methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropan-1-one (Manufactured by BASF)

IRGACURE 2959: 1-[4-(2-Hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (BASF) system Made)

DETX: 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd.)

N-1717: 1,7-bis(9-acridinyl)heptanone (Manufactured by ADEKA)

EAB: 4,4'-bis(diethylamino)benzophenone (manufactured 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 ingredients

Antage W-500: 2,2'-methylene-bis(4-ethyl-6-tert-butylphenol) (manufactured by Kawaguchi Chemical Co., Ltd.)

PM-21: Phosphate containing photopolymerizable unsaturated bond (manufactured by Nippon Kayaku Co., Ltd.)

SH-30: octamethylcyclotetraoxane (manufactured by Toray Dow Corning Co., Ltd.)

Methyl ethyl ketone: Dongshen Chemical Co., Ltd.

1‧‧‧Photosensitive components

10‧‧‧Support film

20‧‧‧Photosensitive layer

22, 30, 122, 123‧ ‧ protective film

100‧‧‧Substrate

101‧‧‧Transparent substrate

102‧‧‧Touch screen

103‧‧‧Transparent Electrode (X Position Coordinate)

104‧‧‧Transparent Electrode (Y Position Coordinate)

105‧‧‧Extension wiring

106‧‧‧Connecting electrode

107‧‧‧Connecting terminal

110, 120‧‧‧Touch panel electrodes

130‧‧‧Photomask

200‧‧‧Touch panel

L‧‧‧active light

Fig. 1 is a schematic cross-sectional view showing an embodiment of a photosensitive element for forming a protective film for an electrode for a touch panel of the present invention.

2(a) to 2(c) are schematic cross-sectional views showing an embodiment of a method of forming a protective film for an electrode for a touch panel of the present invention.

3 is a schematic plan view showing an example of a capacitive touch panel.

4 is a schematic plan view showing another example of a capacitive touch panel.

Fig. 5(a) is a partial cross-sectional view taken along line V-V of the portion C shown in Fig. 3, and Fig. 5(b) is a partial cross-sectional view showing another aspect.

Fig. 6 is a gas chromatogram of the protective film obtained in Example 6 by thermal decomposition gas chromatography mass spectrometry.

1‧‧‧Photosensitive components

10‧‧‧Support film

20‧‧‧Photosensitive layer

30‧‧‧Protective film

Claims (7)

A protective film for an electrode for a touch panel obtained by curing a predetermined portion of a photosensitive layer containing a photosensitive resin composition, wherein the photosensitive resin composition contains a binder polymer, a photopolymerizable compound, and a photopolymerization initiation And the protective film of the electrode for the touch panel described above was detected by thermal decomposition gas chromatography mass spectrometry to detect heptonitrile and benzoic acid. The protective film for the electrode for a touch panel according to the first aspect of the invention, wherein the detection peak area of the benzoic acid in the analysis is 1% to 10% with respect to the detection peak area of the heptonitrile. The protective film for the electrode for a touch panel according to the first or second aspect of the invention is characterized in that the minimum visible light transmittance at 400 nm to 700 nm is 90% or more. The protective film for an electrode for a touch panel according to any one of claims 1 to 3, wherein the adhesive polymer has a carboxyl group and has an acid value of 75 mg KOH/g or more. The protective film for an electrode for a touch panel according to any one of claims 1 to 4, wherein the adhesive polymer has a hydroxyl value of 50 mg KOH/g or less. The protective film for the electrode for a touch panel according to any one of the first to fifth aspects of the invention, which has a thickness of 10 μm or less. A touch panel having a protective film according to any one of claims 1 to 6.