JP2014111722A - Light-shielding composition for touch panel and touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-shielding composition which is suitable as a light-shielding layer of a touch panel, is excellent in chemical resistance, light resistance, and insulating properties, and is capable of forming an image by photolithography, and to provide a cured film thereof.SOLUTION: The light-shielding composition for a touch panel contains: a copolymer (A) which has a plurality of repeating units, comprises 20-90 mol% of a repeating unit derived from diester glycerol in which hydroxyl groups at both ends are esterified with a (meth)acrylate and 10-80 mol% of a repeating unit derived from one or more polymerizable unsaturated compounds copolymerizable with that repeating unit, and has a number-average molecular weight of 2,000-20,000 and an acid value of 35-120 mgKOH/g; and carbon black (B) subjected to an insulation treatment. The cured film is obtained by curing the light-shielding composition.

Description

  The present invention relates to a novel light-shielding composition for a touch panel and a touch panel having a cured film thereof.

  Currently, touch panels are widely used as input means in display devices such as liquid crystal displays. Various types of touch panel configurations are known. Capacitance type (projection type) touch panels are attracting attention because of the advantages such as a bright screen display and the ability to detect multiple touches simultaneously. Yes.

  The capacitive touch panel has a mosaic electrode pattern formed in two layers with a transparent conductive material such as ITO in the screen. The two-layer electrode patterns each have a shape that is continuous in the x-axis direction and the y-axis direction, and is connected to an external control circuit via an extraction wiring made of metal or the like. When a finger touches the screen of the touch panel, a change in capacitance occurs in the nearby electrode pattern, and this can be detected by the control circuit as coordinate information to identify the position of the finger (see, for example, Patent Document 1). .

  When a touch panel circuit is formed on the front glass in such a touch panel, the display wiring can be visually recognized by concealing the extraction wiring such as metal behind the light shielding layer formed in a frame shape around the screen so that it cannot be seen by the user. It has been proposed to improve the design and design. In this case, since the extraction wiring and the electrode pattern are etched after the light shielding layer is formed, the material of the light shielding layer requires chemical resistance against a metal etching solution or an etching resist stripping solution. Further, since the light shielding layer is located near the surface of the display, the material is required to have high light resistance. Furthermore, in order to prevent short-circuiting between electrodes, the light-shielding layer must have insulation properties, and in particular, maintenance of insulation properties after heat treatment at a high temperature required in the touch panel circuit manufacturing process is required.

  Although a light-shielding ink composition can be used as the light-shielding layer, recently, application of a light-shielding photoresist capable of forming an image by photolithography has been attempted. The photolithography process is advantageous because a light-shielding layer having a relatively thin film thickness can be easily formed only in the peripheral portion of the screen. However, when existing materials, such as a light-blocking composition for a black matrix of a color filter, are diverted to touch panel applications, the chemical resistance and light resistance do not meet the required levels, and it is difficult to achieve both properties and insulation. There was a problem.

  On the other hand, although the proposal of the light-shielding composition by which the design was devised for touchscreens is also performed (for example, refer patent document 2, 3), sufficient improvement is not yet aimed at also in such a composition, The appearance of higher performance materials has been desired.

JP 2011-186717 A JP 2012-145699 A WO2012 / 133148 pamphlet

  The present invention has been made in view of the problems of the prior art, and has an object to provide a light-shielding composition for a touch panel that is excellent in chemical resistance, light resistance, and insulation, and capable of image formation by photolithography. To do.

  As a result of investigations to solve the above problems, the present inventors have found that a light-shielding composition containing a copolymer having a specific structure together with carbon black subjected to insulation treatment is suitable for touch panel applications, and the present invention. Was completed.

（ただし、Ｒ¹及びＲ²は、それぞれ独立に水素原子又はメチル基を表す。） That is, the present invention is a copolymer having a plurality of repeating units, 20 to 90 mol% of repeating units represented by the following general formula (1), and one or more types of polymerizability copolymerizable therewith. Copolymer (A) composed of 10 to 80 mol% of a repeating unit derived from an unsaturated compound, having a number average molecular weight of 2,000 to 20,000 and an acid value of 35 to 120 mgKOH / g, and insulated carbon It is the light-shielding composition for touchscreens characterized by containing black (B).

(However, R ¹ and R ² each independently represents a hydrogen atom or a methyl group.)

  Here, it is preferable that A component is comprised only from the repeating unit group which does not contain an aromatic ring.

  Moreover, this invention is also a touchscreen which has the cured film of said light-shielding composition for touchscreens.

Hereinafter, the present invention will be described in detail.
The light-shielding composition of the present invention comprises 20 to 90 mol% of repeating units represented by the general formula (1) and 10 to 80 repeating units derived from one or more polymerizable unsaturated compounds copolymerizable therewith. It contains a copolymer (A) composed of mol%, having a number average molecular weight of 2,000 to 20,000 and an acid value of 35 to 120 mgKOH / g. The component A preferably includes a polymer or copolymer obtained by radical polymerization of a polymerizable unsaturated compound typified by a (meth) acrylic acid derivative by a conventional method as a basic skeleton. Here, (meth) acrylic acid means acrylic acid or methacrylic acid (the same applies below). In radical polymerization, known radical polymerization initiators such as azo compounds and peroxides can be used. In addition, the degree of polymerization may be controlled using a known chain transfer agent, polymerization inhibitor or the like. In addition, 20 to 90 mol% of repeating units represented by the general formula (1) are included in the total number of repeating units constituting the copolymer (A). It is also to show. Hereinafter, the repeating unit is also referred to as a unit.

  In order to introduce the unit represented by the general formula (1) into the component A, there is a method of direct radical polymerization using glycerin-1,3-di (meth) acrylate as a raw material, but in order to prevent gelation due to a crosslinking reaction. In addition, glycidyl (meth) acrylate is added to a polymer or copolymer having a unit derived from (meth) acrylic acid, or a polymer or copolymer having a unit derived from glycidyl (meth) acrylate is added. It is preferable to use a two-step synthesis method of adding (meth) acrylic acid. Such an addition reaction may be carried out by a conventional method, and known reaction catalysts such as tertiary amines, quaternary ammonium salts, tertiary phosphines, and quaternary phosphonium salts can be applied.

  As described above, the copolymer (A) can be copolymerized with 20 to 90 mol% of the repeating unit represented by the general formula (1) and the repeating unit represented by the general formula (1). It has 10 to 80 mol% of repeating units derived from one or more polymerizable unsaturated compounds. That is, the A component can be copolymerized with any unit other than the general formula (1), for example, (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylic acid amide, styrene and derivatives thereof. , Units derived from maleic anhydride and derivatives thereof, vinyl ethers, olefins and the like can be introduced. From the viewpoint of light resistance, it is advantageous to have as little absorption as possible in the ultraviolet light region. Therefore, it is preferable that the component A is composed only of a unit group not containing an aromatic ring.

As the alcohol (R ³ OH) component constituting the (meth) acrylic acid ester or the amine (R ⁴ R ⁵ NH) component constituting the (meth) acrylic acid amide, known ones can be used without particular limitation. Specific examples of R ³ , R ⁴ and R ⁵ include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, Neopentyl, tert-pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, icosyl, cyclopropyl, cyclopentyl, Cyclopentylethyl, cyclohexyl, cyclohexylmethyl, 4-methylcyclohexyl, adamantyl, isobornyl, dicyclopentanyl, dicyclopentenyl, vinyl, allyl, ethynyl, phenyl, tolyl, mesityl Group, naphthyl group, anthryl group, Saturated or unsaturated monovalent hydrocarbon group such as nantril group, benzyl group, 2-phenylethyl group, 2-phenylvinyl group, pyridyl group, piperidyl group, piperidino group, pyrrolyl group, pyrrolidinyl group, imidazolyl group, Examples thereof include saturated or unsaturated monovalent heterocyclic groups such as imidazolidinyl group, furyl group, tetrahydrofuryl group, thienyl group, tetrahydrothienyl group, morpholinyl group, morpholino group, and quinolyl group. Furthermore, at any position such as the above hydrocarbon group and heterocyclic group, a halogen atom, a hydroxy group, a sulfanyl group, a carbonyl group, a thiocarbonyl group, a carboxy group, a thiocarboxy group, a dithiocarboxy group, a formyl group, a cyano group , Nitro group, nitroso group, sulfo group, amino group, imino group, silyl group, ether group, thioether group, ester group, thioester group, dithioester group, amide group, thioamide group, urethane group, thiourethane group, ureido group Moreover, the structure which introduce | transduced the thioureido group etc. as a substituent can also be mentioned. Such a monovalent group may be appropriately selected according to the structure of the target component A, but from the viewpoint of performance and economy, it is a saturated or unsaturated monovalent hydrocarbon having 1 to 20 carbon atoms. It is preferably a group, and more preferably a saturated or unsaturated monovalent hydrocarbon group having 1 to 6 carbon atoms. R ⁴ and R ⁵ may be a hydrogen atom, and R ⁴ and R ⁵ may be bonded to form a ring.

  In addition to the above, units having an epoxy group (for example, (meth) acrylic acid glycidyl, (meth) acrylic acid [4- (glycidyloxy) butyl], (meth) acrylic acid [(3,4-epoxycyclohexyl) methyl ], Units derived from 4- (glycidyloxymethyl) styrene, etc.) and units having an alkoxysilyl group (for example, (meth) acrylic acid [3- (trimethoxysilyl) propyl], (meth) acrylic acid [3- (Triethoxysilyl) propyl], units derived from 4- (trimethoxysilyl) styrene and the like are also preferred as the copolymerization component.

Furthermore, as a derivative of styrene, α-methylstyrene or a compound in which an alkyl group, a halogen atom, a hydroxy group or the like is introduced into the aromatic ring of styrene can be used. As the maleic anhydride derivative, maleic anhydride and alcohol monoester or diester, maleic anhydride and amine amide or imide, and the like can be used. Examples of vinyl ethers include alkyl vinyl ethers, examples of olefins include ethylene, propylene, butadiene, and structures in which hydrogen atoms of these compounds are substituted with halogen atoms or cyano groups. In addition, alkyl vinyl ketone, vinyl acetate and the like can be used.
The alkyl in this paragraph represents a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and such hydrocarbon group may have a branched structure or a ring structure, and is substituted with an arbitrary substituent. It may be.

  A component needs to contain 20-90 mol% of the unit represented by General formula (1), It is more preferable to contain 30-90 mol%, It is especially preferable to contain 30-60 mol%. When the number of units represented by the general formula (1) is less than this, the chemical resistance and insulation properties of the light-shielding composition are insufficient. On the other hand, there is no functional problem due to the large number of units represented by the general formula (1), but if the ratio is too large, it becomes difficult to achieve both control of the acid value within a predetermined range. Therefore, the upper limit of the unit represented by the general formula (1) needs to be 90 mol%.

  In addition, the number average molecular weight of the component A needs to be in the range of 2,000 to 20,000, and more preferably in the range of 5,000 to 15,000. When the number average molecular weight is smaller than this, the chemical resistance and insulating properties of the light-shielding composition are insufficient. On the contrary, when the number average molecular weight is larger, it is difficult to form an image by photolithography. Although there is no restriction | limiting in particular about the weight average molecular weight of A component, It is preferable that dispersity (weight average molecular weight / number average molecular weight) exists in the range of 1-4. These molecular weight values can be determined by GPC (SEC) measurement.

（ただし、Ｒ¹及びＲ²は、それぞれ独立に水素原子又はメチル基を表し、Ｚはジカルボン酸無水物の２価の残基を表す。） Furthermore, the acid value of the component A is required to be 35 to 120 mgKOH / g, and more preferably 50 to 80 mgKOH / g. When the acid value is out of this range, the balance of solubility in an alkaline developer is lost, and image formation by photolithography becomes difficult. The acid value can be imparted to the component A by typically copolymerizing units derived from (meth) acrylic acid at a predetermined molar ratio, which is represented by the following general formula (2). The introduction of units is also preferred. The unit represented by the general formula (2) can be synthesized by adding a dicarboxylic acid anhydride to the unit represented by the general formula (1).

(However, R ¹ and R ² each independently represents a hydrogen atom or a methyl group, and Z represents a divalent residue of a dicarboxylic acid anhydride.)

Known dicarboxylic acid anhydrides can be used without particular limitation. For example, succinic anhydride (Z = ethylene group), maleic anhydride (Z = vinylene group), cyclohexane-1,2-dicarboxylic acid anhydride ( Z = cyclohexane-1,2-diyl group), cyclohexene-1,2-dicarboxylic acid anhydride (Z = cyclohexene-1,2-diyl group), cyclohexene-4,5-dicarboxylic acid anhydride (Z = cyclohexene- 4,5-diyl group), norbornane-2,3-dicarboxylic anhydride (Z = norbornane-2,3-diyl group), phthalic anhydride (Z = 1,2-phenylene group), benzene-1,2 , 4-tricarboxylic acid-1,2-anhydride (Z = 4-carboxy-1,2-phenylene group), cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (Z = 4-carboxy-1,2-diyl group), and the like.
In addition to the above units, dicarboxylic acid anhydrides to (meth) acrylic acid esters having a hydroxy group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc. A unit derived from a structure to which is added, a unit derived from maleic anhydride and a derivative thereof, and the like can also be used.

  The reason why the component A is suitable for a light-shielding composition for a touch panel is not necessarily clear, but the unit represented by the general formula (1) has a polymerizable unsaturated bond at its end, and thus has a dense cross-linked structure. It is presumed that a cured film excellent in chemical resistance, light resistance and insulation can be formed. Moreover, about A component, it can use combining 2 or more types of copolymers from which a composition differs.

  The light-shielding composition of the present invention contains carbon black (B) subjected to insulation treatment. For carbon black insulation treatment, a method of coating with a resin (for example, JP-A-9-95625), a method of oxidizing with an oxidizing agent (for example, JP-A-11-181326), a polymer compound having a reactive group (For example, JP-A-9-265006), a method for chemically modifying with an organic group (for example, JP-T-2008-517330), a method for using a graft reaction and coating with a resin together (for example, JP-A-2002-51730). No. 249678), a method of coating with a dye (for example, WO2013 / 129555 pamphlet) and the like are known, but the component B may be any method. As an insulating index, it is preferable that the surface resistivity of the cured film of the light-shielding composition is 10 10 Ω / sq or more, and an insulating treatment capable of realizing this is preferable. When carbon black not subjected to insulation treatment is used, the surface resistivity of the cured film of the light-shielding composition is generally less than 10 8 Ω / sq. is there. About B component, you may use it in combination of 2 or more types.

  The light-shielding composition of the present invention preferably contains 20 to 70% by weight of the A component and B component in the solid content, more preferably 30 to 50% by weight, respectively. Here, solid content means components other than the solvent contained in the light-shielding composition (the solvent will be described later). When the content of the component A is less than the above range, the chemical resistance, light resistance and insulation are insufficient. On the other hand, when the content is large, it is difficult to design a light-shielding composition. On the other hand, when the content of the B component is less than the above range, the light shielding property is insufficient. On the contrary, when the content is large, image formation by photolithography becomes difficult. In addition, as a light-shielding parameter | index, it is preferable that the optical density of the cured film of a light-shielding composition is 2.0 / micrometer or more.

  The light-shielding composition of the present invention can contain a compound (C) having a polymerizable unsaturated bond other than the component A for the purpose of controlling curability and photolithography performance. As the component C, known compounds conventionally used in photosensitive compositions can be used without particular limitation. For example, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (Meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, (meth) acrylic acid ester derivatives such as dipentaerythritol hexa (meth) acrylate, bisphenol A type epoxy di (meth) acrylate, bisphenol F type epoxy di (meth) acrylate (Meth) such as bisphenolfluorene type epoxy di (meth) acrylate, phenol novolac type epoxy poly (meth) acrylate, cresol novolac type epoxy poly (meth) acrylate It can be preferably used acrylic acid epoxy ester derivatives. In addition, a reaction product of the (meth) acrylic acid derivative and a compound having an (preferably plural) isocyanate group or an acid anhydride group in the structure is also suitable. In addition to (meth) acrylic acid derivatives, maleic acid derivatives, maleimide derivatives, crotonic acid derivatives, itaconic acid derivatives, cinnamic acid derivatives, vinyl derivatives, vinyl alcohol derivatives, vinyl ketone derivatives, vinyl aromatic derivatives, etc. it can. These compounds having a polymerizable unsaturated bond may be those having a multifunctional function, further having a thermally reactive functional group such as an epoxy group or an alkali-soluble functional group such as a carboxy group. Good. Although the compounding quantity of C component is not specifically limited, It is preferable that it is 1-30 weight% in solid content of a light-shielding composition, and it is more preferable that it is 5-20 weight%. As the component C, only one type of compound may be used, or a plurality of components may be used in combination.

The light-shielding composition of the present invention may contain a photopolymerization initiator and / or a dye sensitizer (D) for the purpose of enhancing photocurability. As the component D, known compounds conventionally used in photosensitive compositions can be used without particular limitation. For example, acetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, Acetophenone compounds such as benzyl dimethyl ketal, benzophenone, 2,4,6-trimethylbenzophenone, benzophenone compounds such as 4,4'-bis (N, N-diethylamino) benzophenone, benzoin such as benzoin ethyl ether and benzoin-tert-butyl ether Ether compounds, 2-methyl-1- [4- (methylsulfanyl) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2- (N, N-dimethylamino) -1- (4-morpholinophenyl) ) Α-Aminoalkylphenol such as butan-1-one Compounds, thioxanthone compounds such as thioxanthone and 2,4-diethylthioxanthone, organic peroxides such as 3,3 ′, 4,4′-tetrakis (tert-butylperoxycarbonyl) benzophenone, 2,2′-bis (2 -Chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2-biimidazole and other biimidazole compounds, bis (η ⁵ -cyclopentadienyl) bis [2,6-difluoro-3- ( 1-pyrrolyl) phenyl] titacene compounds such as titanium, 2,4,6-tris (trichloromethyl) -1,3,5-triazine, 2- [3,4- (methylenedioxy) phenyl] -4,6 -Triazine compounds such as bis (trichloromethyl) -1,3,5-triazine, (2,4,6-trimethylbenzoyl) diphenylphosphite Oxides, acylphosphine oxide compounds such as bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, quinone compounds such as camphorquinone, 1- [4- (phenylsulfanyl) phenyl] octane-1,2-dione = 2 -O-benzoyloxime, 1- [9-ethyl-6- (2-methylbenzoyl) carbazol-3-yl] ethanone = O-acetyloxime, (9-ethyl-6-nitrocarbazol-3-yl) [4 Examples include oxime ester compounds such as-(2-methoxy-1-methylethoxy) -2-methylphenyl] methanone = O-acetyloxime. Among these, an oxime ester compound is particularly preferable in terms of enhancing the sensitivity of the light-shielding composition, and an oxime ester compound having a carbazole skeleton as a chromophore is more preferable. Although the compounding quantity of D component is not restrict | limited in particular, it is preferable that it is 0.1-20 weight% in solid content of a light-shielding composition, and it is more preferable that it is 1-10 weight%. As the component D, only one type of compound may be used, or a plurality may be used in combination.

  The light-shielding composition of the present invention can contain an epoxy compound (E) for the purpose of further improving chemical resistance. As the E component, known compounds that are commercially available as epoxy resins and the like can be used without particular limitation. For example, bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol fluorene type epoxy compounds, phenol novolac type Epoxy compound, cresol novolac type epoxy compound, glycidyl ether of polyhydric alcohol, glycidyl ester of polyvalent carboxylic acid, polymer or copolymer having epoxy group and not corresponding to component A, 3,4-epoxycyclohexane 1,2-epoxy-4- (2-oxiranyl) cyclohexane addition of 2,2-bis (hydroxymethyl) -1-butanol to alicyclic epoxy compounds represented by carboxylic acid (3,4-epoxycyclohexyl) methyl Thing (example If Daicel Ltd. "EHPE3150"), epoxidized polybutadiene (e.g., manufactured by Nippon Soda Co., Ltd. "NISSO-PB · JP-100"), and epoxy compounds having a silicone backbone. These components are preferably compounds having an epoxy equivalent of 100 to 300 g / eq and a number average molecular weight of 100 to 5,000. Although the compounding quantity of E component is not restrict | limited in particular, it is preferable that it is 1-20 weight% in solid content of a light-shielding composition, and it is more preferable that it is 2-10 weight%. As the E component, only one kind of compound may be used, or a plurality thereof may be used in combination.

  The light-shielding composition of the present invention may contain a dispersant (F) for the purpose of stably dispersing the component B in the light-shielding composition. As the F component, known compounds conventionally used for dispersing pigments (such as compounds commercially available under the names of dispersants, dispersion wetting agents, dispersion accelerators, etc.) can be used without particular limitation. , Cationic polymer dispersants, anionic polymer dispersants, nonionic polymer dispersants, pigment derivative dispersants (dispersion aids), and the like. In particular, it has a cationic functional group such as an imidazolyl group, pyrrolyl group, pyridyl group, primary, secondary or tertiary amino group as an adsorption point to the pigment, an amine value of 1 to 100 mgKOH / g, and a number average molecular weight Is preferably a cationic polymer dispersant having a molecular weight of 1,000 to 100,000. Examples of such cationic polymer dispersants are disclosed in JP-A-9-169821. Although the compounding quantity of F component is not restrict | limited in particular, it is preferable that it is 1-25 weight% in solid content of a light-shielding composition, and it is more preferable that it is 2-15 weight%. As the F component, only one kind of compound may be used, or a plurality thereof may be used in combination. High viscosity substances such as resins generally have an action of stabilizing the dispersion, but those not having the ability to promote dispersion are not treated as dispersants. However, it is not limited to use for the purpose of stabilizing dispersion.

  The light-shielding composition of the present invention can contain a solvent (G). Known compounds can be used as the G component, for example, ester solvents (butyl acetate, cyclohexyl acetate, etc.), ketone solvents (methyl isobutyl ketone, cyclohexanone, etc.), ether solvents (diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, etc.), Use alcohol solvents (3-methoxybutanol, ethylene glycol mono-t-butyl ether, etc.), aromatic solvents (toluene, xylene, etc.), aliphatic solvents, amine solvents, amide solvents without particular limitation. Can do. From the viewpoint of safety, ester or ether solvents having a propylene glycol skeleton, such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, propylene glycol monomethyl. Ether acetate, propylene glycol monoethyl ether acetate, propylene glycol diacetate and the like are preferably used. Further, 3-methoxybutyl acetate, 3-methoxy-3-methylbutyl acetate, 1,3-butylene glycol diacetate and the like having a similar structure are also preferable. Although there is no restriction | limiting in particular about solid content concentration of a light-shielding composition, As a light-shielding composition for touchscreens, it is common that solid content concentration is adjusted in the range of 10 to 30 weight%. In order to improve the coating property of the light-shielding composition, 30 to 90% by weight of a solvent having a boiling point of less than 150 ° C. at normal pressure and 10 to 70% by weight of a solvent having a boiling point of 150 ° C. or more at normal pressure are used in combination. It is preferable to control the drying property of the composition.

  The light-shielding composition of the present invention may contain other optional components as necessary, and may contain, for example, a coloring material, a filler, a resin, an additive and the like. Here, dyes, organic pigments, inorganic pigments and the like are used as coloring materials, silica and talc are used as fillers, vinyl resins, polyester resins, polyamide resins, polyimide resins, polyurethane resins, polyether resins, and melamine resins as resins. Examples of the additives include a crosslinking agent, a surfactant, a silane coupling agent, a viscosity modifier, a wetting agent, an antifoaming agent, an antioxidant, and an ultraviolet absorber. As these optional components, known compounds can be used without particular limitation. Examples of the light-shielding composition for touch panels include surfactants (fluorine-based surfactants, silicone-based surfactants, etc.) and silane coupling agents (3- (glycidyloxy) propyltrimethoxysilane, 3-isocyanatopropyltriethoxy). It is advantageous to use silane, 3-ureidopropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3- (phenylamino) propyltrimethoxysilane, 3-((meth) acryloyloxy) propyltrimethoxysilane, etc.) The total content is preferably 10% by weight in the solid content of the light-shielding composition. A compound having a sulfanyl group (preferably two or more) is also useful because it has an effect of improving the performance of photolithography.

  The production method of the light-shielding composition of the present invention is not particularly limited, but the carbon black (B) subjected to insulation treatment is dispersed in a solvent (G) or the like (preferably using a dispersant (F)). A method of preparing a light-shielding composition by preparing a dispersion in advance and blending the copolymer (A), a photopolymerization initiator and / or a dye sensitizer (D) with the dispersion liquid can be exemplified. There is also a method in which carbon black (B) subjected to insulation treatment is dispersed in a composition in which copolymer (A) or the like is dissolved in solvent (G). For the preparation of the dispersion, a known pigment dispersion method can be used, and examples thereof include processing by a three-roll, kneader, bead mill and the like.

  The light-shielding composition of the present invention can be applied to a substrate or the like and cured by light irradiation, heat baking, or the like to obtain a cured film. As a method for applying the light-shielding composition, a known method can be used, and examples thereof include application by a spin coater, bar coater, slit coater and the like. Moreover, after application | coating, it is preferable to dry a light-shielding composition using a hotplate, a reduced pressure dryer, etc. However, the application and drying methods are not particularly limited.

  A known method can be used for curing by light irradiation, and examples thereof include ultraviolet light irradiation using a xenon lamp, a halogen lamp, a tungsten lamp, an ultra-high pressure mercury lamp, a high-pressure mercury lamp, a medium-pressure mercury lamp, a low-pressure mercury lamp and the like as a light source. . When such light irradiation is performed, an image can be formed on a substrate by performing image exposure using a photomask or the like and further processing with a developer. The developer is not particularly limited as long as it is a developer that dissolves an unexposed part and does not dissolve an exposed part, but is preferably an alkaline aqueous solution containing various additives. Here, examples of the alkali component of the developer include alkali metal carbonates, alkali metal hydroxides, and quaternary ammonium hydroxides. Examples of additives include organic solvents, surfactants, and antifoaming agents. Agents, fungicides and the like. As a developing method, a known method can be used, and examples thereof include immersion development, spray development, brush development, and ultrasonic development. The method of light irradiation and development is not particularly limited.

  Furthermore, in order to increase the strength of the cured film, it is preferable to carry out heat baking after light irradiation. A known method can be used as the method for heating and baking, and examples thereof include a hot plate and a hot air oven, but are not particularly limited.

Although it does not restrict | limit especially about the curing conditions of a light-shielding composition, About 10-1000mJ / cm < ² > ultraviolet light irradiation is used about photocuring, It is preferable to perform 20-60 minutes baking at 200-250 degreeC about thermosetting. .

  In addition, a well-known method can be utilized as a method of producing a touch panel using the cured film of the light-shielding composition of the present invention.

  The light-shielding composition for a touch panel of the present invention is extremely useful because it can form a cured film excellent in chemical resistance, light resistance and insulation. In particular, since image formation by photolithography is possible, it is also preferable from the viewpoint of excellent touch panel productivity.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

[Example 1]
(Preparation of light-shielding composition)
Mixing was performed according to the composition shown in Table 1, and the mixture was stirred and mixed at room temperature for 3 hours to dissolve or disperse the solid component in a solvent to prepare a light-shielding composition. The numerical value of a composition is a weight part, and is described so that the total of solid content may be 100 weight part. Some solid components were synthesized from the beginning in a solvent (propylene glycol monomethyl ether acetate), but in that case, the numerical value of the composition indicates the weight part as solid content, and the solvent to be brought in Minutes are included in the weight parts of the solvent. In addition, the carbon black subjected to insulation treatment is a dispersion liquid previously dispersed in a solvent using a dispersant (25.0% by weight of carbon black insulated by a resin coating, 4.0% by weight of a cationic polymer dispersant). %, Copper phthalocyanine derivative type dispersant 1.0% by weight, propylene glycol monomethyl ether acetate 70.0% by weight). The components used in the formulation of the examples are shown below.

A-1: units derived from methacrylic acid {14} units derived from methyl methacrylate {30} units derived from cyclohexyl methacrylate {20} —represented by general formula (1), R ¹ , R ² A copolymer composed of units {36} in which both are methyl groups (number average molecular weight 10,000, acid value 50 mgKOH / g)
(The braces in brackets indicate the molar ratio, and so on)
A-2: Unit derived from methacrylic acid {30}-Unit derived from methyl methacrylate {22}-Unit derived from cyclohexyl methacrylate {28}-represented by general formula (1), R ¹ , R ² A copolymer composed of units {20} in which both are methyl groups (number average molecular weight 10,000, acid value 120 mgKOH / g)
A-3: units derived from methacrylic acid {10} units derived from methyl methacrylate {40} units derived from dicyclopentanyl acrylate {10} —represented by general formula (1), R ¹ , A copolymer composed of units {40} in which both R ² are methyl groups (number average molecular weight 5,000, acid value 35 mgKOH / g)
A-4: Unit {20} derived from methacrylic acid unit {30} derived from methyl methacrylate unit {30}-Represented by the general formula (1), R ¹ and R ² are both methyl groups {50} Constructed copolymer (number average molecular weight 15,000, acid value 70 mgKOH / g)
B-1: Carbon Black Insulated with Resin Coating Here, “A-” and “B-” indicate that they correspond to the A and B components of the present invention, respectively.

C-1: Dipentaerythritol hexaacrylate D-1: (9-Ethyl-6-nitrocarbazol-3-yl) [4- (2-methoxy-1-methylethoxy) -2-methylphenyl] methanone = O— Acetyloxime D-2: 1- [9-Ethyl-6- (2-methylbenzoyl) carbazol-3-yl] ethanone = O-acetyloxime E-1: Phenol novolac epoxy compound (“jER154” manufactured by Mitsubishi Chemical Corporation) )
E-2: 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol (“EHPE3150” manufactured by Daicel)
F-1: Cationic polymer dispersant F-2: Copper phthalocyanine derivative type dispersant G-1: Propylene glycol monomethyl ether acetate G-2: Cyclohexanone Here, “C-”, “D-”, “E-”, “ "F-" and "G-" indicate that they correspond to the C to G components of the present invention.

S-1: 3-isocyanatopropyltriethoxysilane S-2: Fluorosurfactant (“Megafac F-556” manufactured by DIC)
Here, “S-” represents other optional components used as necessary.

(Evaluation of light-shielding composition: chemical resistance)
The said light-shielding composition was apply | coated to the alkali free glass substrate using the spin coater, and it was made to dry for 2 minutes with a 90 degreeC hotplate, and the test piece was produced. At this time, the coating conditions (spin rotation speed) were adjusted so that a cured film having a thickness of 1.5 μm was obtained. Next, 100 mJ / cm ² ultraviolet rays (numerical values are based on i-line) are irradiated with an ultrahigh pressure mercury lamp with an illuminance of 30 mW / cm ² through a photomask having a frame-like pattern on the touch panel screen, and the test piece is imaged. Exposure was performed. Thereafter, the test piece was treated with an alkaline developer at 25 ° C. (10-fold diluted solution of “V-2401ID” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) for 1 minute, and further washed with water to develop the image. Finally, the test piece was baked in a hot air oven at 230 ° C. for 30 minutes to obtain a cured film of the light-shielding composition.
The test piece on which the cured film of the light-shielding composition is formed is immersed in an etching resist stripping solution (mixture of 2-aminoethanol 30% and diethylene glycol monobutyl ether 70%) at 60 ° C. for 10 minutes, washed with water, and dried. Then, the thickness of the cured film was measured, and three-stage evaluation was performed according to the following criteria. ○ (Good): Change in film thickness before and after immersion in stripping solution is 2% or less, ▲ (slightly bad): over 2% and 5% or less, x (poor): over 5%.

(Evaluation of light-shielding composition: light resistance)
A test piece on which a cured film of the light-shielding composition was formed was prepared in the same manner as in the chemical resistance evaluation. After irradiating the test piece from the glass surface with a 2.5 kW xenon lamp for 500 hours, the cured film was subjected to a cross-cut-tape peeling test and evaluated in three stages according to the following criteria. ○: No peeling, ▲: Slight peeling is observed, ×: Numerous peeling is observed.

(Evaluation of light-shielding composition: insulation)
A test piece on which a cured film of the light-shielding composition was formed was prepared in the same manner as in the chemical resistance evaluation. After the test piece was further baked in a hot air oven at 230 ° C. for 180 minutes, the surface resistivity of the cured film was measured at a voltage of 10 V, and three-stage evaluation was performed according to the following criteria. ◯: Surface resistivity is 10 10 Ω / sq or more, ▲: 10 8 Ω / sq or more and less than 10 10 Ω / sq, ×: 10 8 Ω / sq or less.

(Evaluation of shading composition: workability)
A test piece on which a cured film of the light-shielding composition was formed was prepared in the same manner as in the chemical resistance evaluation. The formed image was observed with an optical microscope, and three-stage evaluation was performed according to the following criteria. ◯: No image pattern chipping or undeveloped residue is observed, ▲: Slightly chipped or undeveloped residue is observed, ×: Missing or undeveloped residue is observed.

  The evaluation results of the light-shielding composition of Example 1 are shown in Table 2. The light-shielding composition of Example 1 satisfied both chemical resistance, light resistance and insulation required for touch panel applications, and was excellent in photolithography processability. The optical density of the cured film of the light-shielding composition was 3.1 / μm.

[Examples 2 to 8]
The composition of Example 1 was changed as shown in Table 1, and the others were prepared and evaluated in the same manner as Example 1 except for the light-shielding compositions of Examples 2-8. The evaluation results are shown in Table 2. The light-shielding compositions of Examples 2 to 8 satisfied both chemical resistance, light resistance, and insulation required for touch panel applications, and were also excellent in photolithography processability. Moreover, the optical density of the cured film of the light-shielding composition was 3.1 / μm in Examples 2 to 4, and 2.4 / μm in Examples 5 to 8.

[Comparative Examples 1-4]
The composition of Example 1 was changed as shown in Table 3, and the others were the same as in Example 1, and the light-shielding compositions of Comparative Examples 1 to 4 were prepared and evaluated. The components used for the formulation of the comparative example are shown below.

AX-1: Unit derived from methacrylic acid {16}-Unit derived from methyl methacrylate {16}-Copolymer composed of unit {68} derived from benzyl methacrylate (number average molecular weight 10,000, acid Value 60mgKOH / g)
AX-2: units derived from methacrylic acid {18} units derived from methyl methacrylate {50} units derived from cyclohexyl methacrylate {20} —represented by general formula (1), R ¹ , R ² A copolymer composed of units {12} in which both are methyl groups (number average molecular weight 10,000, acid value 80 mgKOH / g)
AX-3: Alkali developing photosensitive resin having a bisphenolfluorene skeleton (solid content of “V-259ME” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
BX-1: Carbon black not subjected to insulation treatment Here, “AX-” and “BX-” indicate that they are out of the ranges of the A and B components of the present invention, respectively.

  Table 4 shows the evaluation results of the light-shielding compositions of Comparative Examples 1 to 4. The light-shielding compositions of Comparative Examples 1 to 4 could not satisfy various properties required for touch panel applications.

  The light-shielding composition of the present invention is not only suitable for forming a light-shielding layer of a touch panel, but can also be preferably used for forming a black matrix of a color filter or a light-shielding solder resist film. Moreover, the use as coloring components, such as a coating material, printing ink, writing instrument ink, and plastics, and the application to uses, such as an optical filter, as a light absorptive material are also considered.

Claims (3)

A copolymer having a plurality of repeating units, derived from 20 to 90 mol% of repeating units represented by the following general formula (1), and one or more polymerizable unsaturated compounds copolymerizable therewith Containing a copolymer (A) composed of 10 to 80 mol% of repeating units, having a number average molecular weight of 2,000 to 20,000 and an acid value of 35 to 120 mgKOH / g, and carbon black (B) subjected to insulation treatment A light-shielding composition for a touch panel.

(However, R ¹ and R ² each independently represents a hydrogen atom or a methyl group.)   The light-shielding composition for a touch panel according to claim 1, wherein the component A comprises only a repeating unit group containing no aromatic ring.   The touch panel which has the cured film of the light-shielding composition for touchscreens of Claim 1 or 2.