TWI671589B - White photosensitive resin composition, cured product using the same, and touch panel including such cured product as a component - Google Patents

Abstract

An object of the present invention is to provide a white photosensitive resin composition which has not only sufficient light discoloration resistance but excellent development characteristics, a cured product using the same, and a touch panel including the cured product as a component.

The present invention provides a white photosensitive resin composition, a cured product obtained by patterning the white photosensitive resin composition by photolithography and then thermally curing the same, and a touch panel including the cured object. The white photosensitive resin composition contains (A) a predetermined alkaline soluble resin, (B) a photopolymerizable monomer having at least one ethylenically unsaturated bond, (C) a photopolymerization initiator, and ( D) The proportion of the white photosensitive resin composition of the white light-shielding material in the solid content containing the monomer component that becomes a solid content after photocuring. (A) is 1 to 55% by mass, relative to (A) 100% by mass. Parts, (B) is 10 to 100 parts by mass, and (C) is 0.1 to 40 parts by mass, and (D) is 1 to 95 parts by mass with respect to 100 parts by mass of the total amount of (A) and (B).

Description

White photosensitive resin composition, cured product using the same, and touch panel containing the cured product as a component

The present invention relates to a white photosensitive resin composition capable of forming a desired pattern and having excellent light discoloration resistance. Specifically, as the white photosensitive resin composition, a cured product thereof is used. As the hardened material, a white material for decoration of a touch panel can be used, and a touch panel using the hardened material as a component.

In recent years, due to the diversification of information equipment and the trend of miniaturization and weight reduction of mobile terminals, mobile phones, mobile information terminals, and car navigation systems are led by flat screen displays such as touch panels and liquid crystal display panels. Input display One-machine formed touch panel type flat panel display has become popular in the market. Depending on the structure and detection method of the touch panel, there are various types such as a resistive film type or an electrostatic capacitance type. Among them, the electrostatic capacitance type touch panel is a static formed by having a light-transmitting conductive film (light-transmitting electrode) on a single substrate, and touching (touching) it with a finger or a pen. An electric capacitor detects a change in the amount of a weak current flowing therethrough to identify a person to be touched, and obtains an instruction content as an input signal to drive a liquid crystal display device or the like. Compared with a resistive film type touch panel, an electrostatic capacitance type touch panel has the advantage of obtaining a higher transmittance.

Regardless of the method of the touch panel, in order to detect the input signal or to protect the screen, a transparent protective plate such as cover glass is used on the touch panel. Here, a transparent protective plate is provided on the touch panel, or the transparent protective plate itself constitutes the touch panel. In addition, the transparent protective plate also includes a functional film such as a low-reflection film, an anti-glare film, a hard coat film, and an electromagnetic barrier film.

In addition, recently, as electronic devices are becoming more and more fashionable, in transparent protective plates of portable terminal devices such as mobile phones, decorations such as LCD wiring are generally provided by various printing methods. For example, Patent Documents 1 and 2 disclose an electronic device including a protective panel on the surface of a transparent protective plate. The protective panel is a decorative film formed by forming a window forming layer having a transparent window portion on the back of a hard coating film in advance. The transparent protective plate is adhered in a laminated state, wherein the transparent protective plate is composed of a touch panel including a movable electrode film and a fixed electrode plate, the movable electrode film is laminated with a decorative film, and the fixed electrode plate is connected with the movable electrode An air layer is formed between the thin films, and the movable electrode thin film is adhered to the peripheral edge portion. In the past, a transparent protective plate with a decoration and a touch panel are generally formed separately as described above, and then combined in subsequent steps. However, recently, the demand for thinness of mobile phones has been increasing. In addition, there is a discussion on directly forming a touch panel by decorating a transparent protective plate, thereby reducing the number of steps. A method of patterning a photosensitive resin with a thinner thickness has attracted attention. A method for manufacturing a touch panel using this method is described in Patent Document 3. The color of the decorative portion of the decorative transparent protective plate for a touch panel is generally black, but with the trend of electronic devices, there is a need for white decoration.

However, especially in the case of a white photosensitive resin, when the coating film is heated and hardened or when the touch panel is manufactured, the heat may cause discoloration and coloration, and there is a concern that the light reflectance may be reduced. In addition, if the light resistance is insufficient, it may be colored during use of the touch panel, or the light reflectance may be reduced. Since the white photosensitive resin for a touch panel is particularly noticeable in terms of discoloration and reduction in reflectance, there is a concern about reducing the value of a product, and a solution is being sought.

[Advanced technical literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2007-279756

[Patent Document 2] Japanese Patent Laid-Open No. 2007-323092

[Patent Document 3] Japanese Patent Laid-Open No. 2013-8272

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a white photosensitive resin composition having sufficient light discoloration resistance and excellent development characteristics, a cured product using the same, and a composition including the cured product. Composition of touch panel.

As a result of intensive research in order to solve the aforementioned problems, the inventors of the present case found that the copolymer (A) and the photopolymerizable monomer (B) contain a polymerizable unsaturated group-containing basic soluble resin having a specific structure, The photopolymerization initiator (C) and the white photosensitive resin composition of the white light-shielding material (D) can be patterned by light, and a hardened material having excellent light discoloration resistance can be obtained, and is useful for touch control. Use of panel decoration. That is, the gist of the present invention is as follows.

(1) The present invention is a white photosensitive resin composition containing 20 to 90 mol% of repeating units represented by the following general formula (1), and 5 to 50 mol% of repeating units having an alicyclic structure. And, a copolymer (A from 5 to 50 mol% of repeating units derived from a polymerizable unsaturated compound copolymerizable with these and having a weight average molecular weight of 10,000 to 100,000 and an acid value of 35 to 120 mgKOH / g ), A photopolymerizable monomer (B) having at least one ethylenically unsaturated bond, a photopolymerization initiator (C), and a white light-shielding material (D), wherein the photopolymerizable monomer contains solid The proportion of the solid content of the monomer component is 1 to 55% by mass, with respect to 100 parts by mass of (A), 10 to 100 parts by mass, and (A) with respect to (A) and (B). The total amount is 100 parts by mass, (C) is 0.1 to 40 parts by mass, and (D) is 1 to 95% by mass.

(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a methyl group.)

(2) The present invention is the white photosensitive resin composition according to (1), wherein the component (A) is composed only of a repeating unit group not containing an aromatic ring.

(3) The present invention is a white photosensitive resin composition containing (E) an epoxy compound or an epoxy resin in addition to (1) or (2).

(4) The present invention is a cured product obtained by patterning the white photosensitive resin composition according to any one of (1) to (3) by a photolithography method and then thermally curing it. .

(5) The present invention is a touch panel containing the hardened body as described in (4).

Hereinafter, the present invention will be described in detail.

The copolymer of (A) in the white photosensitive resin composition of the present invention has (i) a repeating unit represented by the following general formula (1) of 20 to 90 Molar%, (ii) 5 to 50 Molar% of repeating units having an alicyclic structure, and (iii) 5 to 50 Molar% of repeating units derived from polymerizable unsaturated compounds copolymerizable with these, Moreover, the weight-average molecular weight is 10,000 to 100,000, and the alkali-soluble resin containing a polymerizable unsaturated group has an acid value of 35 to 120 mgKOH / g.

(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a methyl group.)

The component (A) is preferably a polymer or copolymer obtained by radically polymerizing a polymerizable unsaturated compound typified by a (meth) acrylic acid derivative as a basic skeleton. The "(meth) acrylic acid" herein means acrylic acid or methacrylic acid (the same shall apply hereinafter). In the radical polymerization, a known radical polymerization initiator such as an azo compound or a peroxide may be used, and a known chain transfer agent, a polymerization inhibitor, or the like may be used to control the degree of polymerization. The term "containing 20 to 90 mole% of the repeating unit represented by the general formula (1)" refers to the total repeating unit constituting the copolymer (A). The proportion of the number of repeating units represented by the general formula (1) is 20 to 90 mole%. Hereinafter, the repeating unit is sometimes 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 in which glycerin-1,3-di (meth) acrylate is directly used as a raw material and radical polymerization is performed. To prevent gelation caused by a crosslinking reaction, it is preferable to add glycidyl (meth) acrylate to a polymer or copolymer having a unit derived from (meth) acrylic acid, or A two-stage synthesis method of adding (meth) acrylic acid to a polymer or copolymer having units derived from glycidyl (meth) acrylate. This addition reaction can be carried out by a general method, and known reaction catalysts such as tertiary amine, quaternary ammonium salt, tertiary phosphine, and quaternary phosphonium salt can be applied.

The component (A) contains, in addition to the unit represented by the general formula (1), 5 to 50 mol% of a unit having an alicyclic structure. Here, the "alicyclic structure" means a ring structure composed of a saturated or unsaturated hydrocarbon group, and does not include an aromatic ring. In order to introduce this into the component (A), a method using a polymerizable unsaturated compound having an alicyclic structure is simple, so it is preferable. Examples of the polymerizable unsaturated compound having an alicyclic structure include cyclopropyl (meth) acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, and cyclohexyl (meth) acrylate. Esters, dicyclopentyl (meth) acrylate, dicyclopentenyl (meth) acrylate, isoamyl (meth) acrylate, auranyl (meth) acrylate, and the like. There is also a method in which a polymer or copolymer having a unit derived from (meth) acrylic acid is reacted with an alcohol, an amine, an epoxy compound, or the like having an alicyclic structure.

As long as the unit having an alicyclic structure has at least one lipid The ring structure is sufficient, and it may be a branched structure derived from an alicyclic structure, or a halogen atom, a hydroxyl group, a sulfonyl group, a carbonyl group, a thiocarbonyl group, a carboxyl group, a thiocarboxyl group, Dithiocarboxyl, methylamino, cyano, nitro, nitroso, thio, amine, imine, silyl, ether, thioether, ester, thioester, disulfide Structure of substituents such as substituted ester groups, amido groups, thioamido groups, polyurethane groups, thiourethane groups, urea groups, and thiourea groups.

Furthermore, (A) component has 5 to 50 mol% of the unit derived from the polymerizable unsaturated compound which can be copolymerized with the unit represented by the said General formula (1), or the said unit which has an alicyclic structure. That is, any unit other than the unit represented by the general formula (1) or the unit having an alicyclic structure can be copolymerized with the component (A), and for example, (meth) acrylic acid or (meth) acrylic acid can be introduced. Units such as esters, ammonium (meth) acrylate, styrene and its derivatives, maleic anhydride and its derivatives, vinyl ethers, and olefins. The unit derived from the copolymerizable polymerizable unsaturated compound may be used alone, or two or more units may be used, but it is preferable that the total unit when the two or more units are used is 5 to 50 mol%. Here, from the viewpoint of light resistance, it is preferable to use a compound that does not absorb ultraviolet light as much as possible. Therefore, the component (A) is preferably composed of only a unit group not containing an aromatic ring.

The alcohol (R ³ OH) component constituting the (meth) acrylic acid ester or the amine (R ⁴ R ⁵ NH) component constituting the ammonium (meth) acrylic acid can be used without any particular limitation to the known ones. Specific examples of R ³ , R ⁴ and R ⁵ include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, third butyl, pentyl, isopentyl, Neopentyl, third pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, tetradecyl, cetyl, octadecyl, di Decadecyl, vinyl, allyl, ethynyl, phenyl, tolyl, tricresyl, naphthyl, anthryl, phenanthryl, benzyl, 2-phenylethyl, 2-phenylvinyl And other saturated or unsaturated monovalent hydrocarbon groups, or pyridyl, piperidinyl, N-hexahydropyridyl, pyrrolyl, pyrrolidinyl, imidazolyl, imidazolyl, furanyl, tetrahydrofuranyl, thienyl, tetra Saturated or unsaturated monovalent heterocyclic groups such as hydrothienyl, morpholinyl, morpholino group, and quinolinyl. Furthermore, a halogen atom, a hydroxyl group, a sulfofluorenyl group, a carbonyl group, a thiocarbonyl group, a carboxyl group, a thiocarboxyl group, a dithiocarboxyl group, a methylamino group, and a cyano group may be introduced at any positions such as the aforementioned hydrocarbon group and heterocyclic group. , Nitro, nitroso, thio, amine, imine, silicon, ether, thioether, ester, thioester, dithioester, amido, thioamidine Structure of substituents such as amine group, polyurethane group, thiourethane group, urea group, and thiourea group. Such a monovalent group can be appropriately selected according to the structure of the target (A) component, but from the viewpoint of performance and economy, a saturated or unsaturated monovalent hydrocarbon group having 1 to 20 carbon atoms is more preferable, and more preferably It is a saturated or unsaturated monovalent hydrocarbon group having 1 to 6 carbon atoms (but alicyclic structure is not included in this group). In addition, R ⁴ and R ⁵ may be hydrogen atoms, and R ⁴ and R ⁵ may be combined to form a ring.

In addition to the above, as the copolymerization component, a unit having an epoxy group [for example, derived from glycidyl (meth) acrylate, (4- (glycidyloxy) butyl methacrylate), 4 -Units such as (glycidyloxymethyl) styrene ester) or units having an alkoxysilyl group [for example, derived from (meth) acrylic acid [3- (trimethoxysilyl) propyl] (3- (triethoxysilyl) propyl) (meth) acrylic acid, 4- (trimethoxysilyl) benzene Units such as vinyl esters].

Further, a derivative of styrene can be used for a compound in which an alkyl group, a halogen atom, a hydroxyl group, or the like is introduced into an aromatic ring of α-methylstyrene or styrene. In addition, as the maleic anhydride derivative, monoesters or diesters of maleic anhydride and alcohols, and sulfonamide or sulfonimine of maleic anhydride and amines can be used. Examples of the vinyl ethers include alkyl vinyl ethers, and examples of the olefins include ethylene, propylene, butadiene, or a structure in which a hydrogen atom of these compounds is substituted with a halogen atom or a cyano group. In addition, alkyl vinyl ketone, vinyl acetate, and the like can also be used. In addition, the so-called alkyl group in this paragraph means a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may have a branched structure or may be substituted with any substituent.

The component (A) must contain 20 to 90 mol% of the unit represented by the general formula (1), preferably 25 to 75 mol%, and more preferably 30 to 60 mol%. When the number of units represented by the general formula (1) is smaller than the foregoing, the adhesion and the like of the white photosensitive resin composition are insufficient. On the other hand, when there are too many units represented by the general formula (1), there is no problem in organic energy, but when the ratio is too large, it is difficult to control the acid value to a predetermined range at the same time. Therefore, the upper limit of the unit represented by the general formula (1) needs to be set at 90 mol%. In addition, the component (A) must contain 5 to 50 mol% of units having an alicyclic structure, preferably 7 to 40 mol%, and more preferably 10 to 30 mol%.

Units with an alicyclic structure increase light resistance.

The weight average molecular weight of the component (A) must be in the range of 10,000 to 100,000, and more preferably in the range of 15,000 to 50,000. If the weight-average molecular weight is smaller than this, the adhesion and the like of the white photosensitive resin composition may be reduced. Enough, on the other hand, it becomes difficult to form an image from light lithography when it is large.

Further, the acid value of the component (A) must be 35 to 120 mgKOH / g, preferably 50 to 80 mgKOH / g. When the acid value is outside this range, the balance of solubility in the alkaline developer is lost, and it becomes difficult to form an image through light lithography. The acid value imparting of the component (A) is typically carried out by copolymerizing a unit derived from (meth) acrylic acid at a predetermined mole ratio, but it may be introduced by the following general formula (2) Represented unit. The unit represented by the general formula (2) can be synthesized by adding a dicarboxylic anhydride to the unit represented by the general formula (1). The unit system represented by the general formula (2) is classified as a polymerizable unsaturated compound derived from (iii) that can be copolymerized with the unit represented by the general formula (1) or the unit having an alicyclic structure. When the unit (A) contains this unit, it is preferred that the unit represented by the general formula (2) is substituted for the unit derived from the polymerizable unsaturated compound of (iii) and contained in the copolymer (A). A range of 10 to 30 mole%.

(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and Z represents a divalent residue of a dicarboxylic anhydride.)

As the dicarboxylic anhydride, a known one can be used without particular limitation, and examples thereof include succinic anhydride (Z = ethylene), maleic anhydride (Z = ethylene), and cyclohexane-1,2-dicarboxylic anhydride (Z = cyclohexane-1,2-diyl), cyclohexene-1,2-dicarboxylic anhydride (Z = cyclohexene-1,2-diyl), cyclohexene-4,5-di Carboxylic anhydride (Z = cyclohexene-4,5-diyl), norbornane-2,3-dicarboxylic anhydride (Z = norbornane-2,3-diyl), phthalic anhydride (Z = 1, 2-phenyl), benzene-1,2,4-tricarboxylic acid-1,2-anhydride (Z = 4-carboxy-1,2-phenyl), cyclohexane-1,2,4-tricarboxylic acid Acid-1,2-anhydride (Z = 4-carboxycyclohexane-1,2-diyl) and the like.

In addition to the unit of the general formula (2), 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc. may be used. A unit derived from a structure in which a dicarboxylic anhydride is added to a (meth) acrylate having a hydroxyl group, or a unit derived from maleic anhydride and a derivative thereof, etc., as a polymerizable unsaturated compound derived from (iii) The unit.

The reason why the component (A) is suitable for use in a white photosensitive resin composition is unknown, but it is presumed that the polymerizable unsaturated bond at the unit terminal represented by the general formula (1) contains a dense crosslinked structure after hardening, and is helpful A unit having an alicyclic structure for improving light resistance can form a cured film suitable for use in touch panel applications and the like. In addition, as the component (A), two or more kinds of copolymers having different combination compositions can be used. The component (A) is contained in the solid content of the white photosensitive resin composition in an amount of 1 to 55% by mass, and preferably 3 to 50% by mass. Here, the solid content refers to a monomer component containing a white solid resin composition that becomes a solid content after photocuring, but does not include a solvent.

(B) in the white photosensitive resin composition of the present invention Examples of the photopolymerizable monomer having at least one ethylenically unsaturated bond include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-ethylhexyl (Meth) acrylates having a hydroxyl group such as (meth) acrylate, or ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene glycol di (methyl) Acrylate), tetraethylene glycol di (meth) acrylate, tetramethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethyl Alkane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, glycerol (methyl ) Acrylate, sorbitol penta (meth) acrylate, dipentaerythritol penta (meth) acrylate, or dipentaerythritol hexa (meth) acrylate, sorbitol hexa (meth) acrylate, phosphazene Alkyl oxide modified hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate, etc. Type, dendritic polyfunctional acrylates may be used or two or more of these. In addition, the photopolymerizable monomer having at least one ethylenically unsaturated bond is preferably an alkali-soluble resin containing an unsaturated group [(A) component] having two or more photopolymerizable groups. The molecules are cross-linked to each other for use. In addition, the photopolymerizable monomer (B) having at least one ethylenically unsaturated bond does not have a free carboxyl group.

Examples of the (C) photopolymerization initiator of the white photosensitive resin composition of the present invention include acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, and p-diacetone. Acetophenones such as methylaminoacetophenone, dichloroacetophenone, trichloroacetophenone, p-tert-butylacetophenone, diphenylketone, 2-chlorodiphenylketone, p, p Diphenyl ketones such as' -bisdimethylaminodiphenyl ketone, benzyl, benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether and other benzoin ethers, 2- (o-chloro (Phenyl) -4,5-phenylbiimidazole, 2- (o-chlorophenyl) -4,5-bis (m-methoxyphenyl) biimidazole, 2- (o-fluorophenyl)- 4,5-diphenylbiimidazole, 2- (o-methoxyphenyl) -4,5-diphenylbiimidazole, 2,4,5-triarylbiimidazole and other biimidazole compounds, 2 -Trichloromethyl-5-styryl-1,3,4- Diazole, 2-trichloromethyl-5- (p-cyanostyrene) -1,3,4- Diazole, 2-trichloromethyl-5- (p-methoxystyryl) -1,3,4- Halogenated methyldiazole compounds such as diazoles, 2,4,6-ginseno (trichloromethyl) -1,3,5-tris , 2-methyl-4,6-bis (trichloromethyl) -1,3,5-tri , 2-phenyl-4,6-bis (trichloromethyl) -1,3,5-tri , 2- (4-chlorophenyl) -4,6-bis (trichloromethyl) -1,3,5-tris , 2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -1,3,5-tris , 2- (4-methoxynaphthalene) -4,6-bis (trichloromethyl) -1,3,5-tri , 2- (4-methoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-tris , 2- (3,4,5-trimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-tris , 2- (4-methylthiostyryl) -4,6-bis (trichloromethyl) -1,3,5-tri Isohalogenated methyl-S-tri Compounds, 1,2-octanedione, 1- [4- (phenylthio) phenyl]-, 2- (O-benzoinoxime), 1- (4-phenylsulfonylphenyl) Butane-1,2-dione-2-oxime-O-benzoic acid, 1- (4-methylsulfonamidophenyl) butane-1,2-dione-2-oxime-O-acetate O-fluorenyl oxime compounds such as 1- (4-methylsulfonylphenyl) butane-1-one oxime-O-acetate, benzyl dimethyl ketone, thia anthrone, 2 -Keto compounds such as chlorothiaxanthone, 2,4-diethylthioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, 2-ethyl allylquinone, octa Onion quinones such as onion quinone, 1,2-benzoon quinone, and 2,3-diphenyl onion quinone; azobisisobutylnitrile, benzoin peroxide, cumene peroxide , 2-mercaptobenzimidazole, 2-mercaptobenzo Thiol compounds such as azole and 2-mercaptobenzothiazole, and tertiary amines such as triethanolamine and triethylamine. Among these, from the viewpoint of easily obtaining a high-sensitivity white photosensitive resin composition, it is preferable to use O-fluorenyl oxime-based compounds. These photopolymerization initiators may be used in two or more kinds. The photopolymerization initiator of the present invention is used in the sense that it contains a sensitizer.

Examples of the (D) white light-shielding material used in the white photosensitive resin composition of the present invention include white organic pigments and white inorganic pigments. Examples of white organic pigments include organic compound salts having the general formula A ^n- n [B] shown in Japanese Patent Application Laid-Open No. 11-129613 (A represents a substituted stilbene-based fluorescent agent having an anionic group and an osmic acid group. Whitening agents, components such as substituted coumarin-based fluorescent whitening agents, substituted thiophene-based fluorescent whitening agents, and other organic cations such as ammonium and pyridinium having a carbon number of 15 or more, n is (Integer number from 1 to 9), or white organic pigments (e.g., alkylene bis melamine derivatives, such as ethylene dimelamine, N, N'-dicyclohexyl, ethylene bis melamine, etc.) Commercial products include ShigenoxOWP and ShigenoxOWPL (manufactured by Hakkol Chemical Co., Ltd.). Hollow particles of thermoplastic resins described in Japanese Patent Application Laid-Open No. 2008-1072 are used. Hollow particles of ethylene-acrylic acid copolymer (commercially available products are SX866, SX8782 (manufactured by JSR)) and the like.

Examples of the white inorganic pigment include chromium oxide, iron oxide, titanium oxide, titanium white, titanium acid nitride, and titanium nitride. These shading materials contain white organic pigments or white inorganic pigments, and any one of them can be appropriately selected. Two or more kinds may be used, but titanium white is particularly preferred from the viewpoints of good light-shielding property, surface smoothness, dispersion stability, and affinity with resin. The average particle diameter of the white organic pigment or white inorganic pigment (volume average particle diameter by laser diffraction and scattering particle diameter measuring device) used is preferably 20 to 1000 nm, and more preferably 50 to 700 nm.

In addition, the white photosensitive resin composition of the present invention may be changed to shades of gray, pink, or the like depending on the application, or may be used in combination with colored inks or colored inorganic pigments to adjust light-shielding properties without particular limitation. Examples of the colored inorganic pigments used in combination include carbon black, chromium oxide, iron oxide, titanium oxide, titanium black, titanium oxynitride, and titanium nitride. In addition, for the purpose of adjusting the light-shielding property, a two-layer structure with the black light-shielding layer may be used. In the case of a two-layer structure, for example, a white cured film layer can be formed on a glass plate for surface protection, and a light-shielding layer can be formed using a black photosensitive resin composition thereon.

The colored inks (black, cyan, magenta, and yellow inks) used in combination are not particularly limited. As long as the hue and color density are suitable for the purpose of the ink, known water-soluble dyes, oil-soluble dyes, and pigments can be used. To select and use appropriately. Among these, it is preferable to use an oil-soluble dye or pigment that is easily dispersed and dissolved uniformly in a water-insoluble liquid. When an oil-soluble dye is used, the content of the dye is preferably in the range of 0.05 to 20% by mass based on the solid content of the white photosensitive resin composition.

The composition ratio of each component (A) to (D) in the white photosensitive resin composition is the ratio of the solid content containing the monomer component that becomes a solid content after photocuring, and (A) is 1 to 55 mass %, Preferably 3 to 50% by mass, with respect to 100 parts by mass of (A), 10 to 100 parts by mass, preferably 30 to 50 parts by mass, and 100 parts by mass with respect to the total amount of (A) and (B), ( C) is 0.1 to 40 parts by mass, preferably 3 to 30 parts by mass, and (D) is 1 to 95% by mass, preferably 40 to 90% by mass.

When (B) is less than 10 parts by mass with respect to 100 parts by mass of (A), the solubility of the coating film in the developing solution becomes too low, and thus the photolithographic performance is reduced. In addition, when (B) is more than 100 parts by mass relative to 100 parts by mass of (A), the solubility of the film in the developing solution becomes excessively high, and thus the adhesion of the coating film during development decreases.

(C) When the amount is less than 0.1 parts by mass with respect to 100 parts by mass of the total amount of (A) and (B), the coating film becomes non-hardened, and when it exceeds 40 parts by mass, the hardened area will be shaded in proportion The opening area is wide, so light lithography performance will be reduced.

(D) When the solid content is less than 1% by mass, the tinting strength is significantly reduced, and when it is higher than 95% by mass, the viscosity of the ink increases and it becomes difficult to paint a film.

The white photosensitive resin composition of this invention contains the said (A)-(D) component as a main component. In this photosensitive resin composition, in the solid content (containing a monomer component which becomes a solid content after photocuring), the total of the components (A) to (D) may be 70% by mass or more, preferably 80% by mass, It is more preferably 90% by mass or more.

In the white photosensitive resin composition of the present invention, in addition to the above (A) to (D), it is preferable to use a solvent to adjust the viscosity to form a white photosensitive resin composition solution. Examples of the solvent include methanol, ethanol, Alcohols such as n-propanol, isopropanol, ethylene glycol, propylene glycol, terpenes such as α- or β-terpineol, etc., acetone, methyl ethyl ketone, cyclohexanone, N-methyl-2-pyrrole Ketones such as ketones, aromatic hydrocarbons such as toluene, xylene, tetramethylbenzene, cellolysin, methylcellosolve, ethylcellolysin, carbitol, methylcarbitol, ethylcarbitol Alcohol, butylcarbitol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl Ethylene glycol ethers, ethyl acetate, butyl acetate, lysin acetate, ethyl lysin acetate, butyl lysin acetate, carbitol acetate, ethyl carbidine Alcohol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxy-3-methylbutyl acetate, and other acetates And the like can be dissolved and mixed by using these to form a uniform solution-like composition. The amount of the solvent may vary depending on the target viscosity, but it is preferably in the range of 60 to 90% by mass in the white photosensitive resin composition solution.

The present invention can also be a white photosensitive resin composition containing (E) an epoxy compound or an epoxy resin in addition to the components (A) to (D), and the compound can be used as the (E) epoxy compound or epoxy resin. Examples include phenyl glycidyl ether, p-butylphenol glycidyl ether, triglycidyl isocyanurate, diglycidyl isocyanurate, allyl glycidyl ether, glycidyl methacrylate, etc. Epoxy compounds, bisphenol A epoxy resin, bisphenol F epoxy resin, 3,3 ', 5,5'-tetramethyl-4,4'-bisphenol epoxy resin, bisphenol hydrazone Type epoxy resins such as bisphenol epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins and other novolac epoxy resins, glycidyl ethers of polyhydric alcohols, polycarboxylic acids Glycidyl Ester, 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexenecarboxylate, 2,2-bis (hydroxymethyl) -1-butanol, 1,2-epoxy- Aliphatic epoxy compounds such as 4- (2-oxiranyl) cyclohexane adducts, epoxy resins having polysiloxane such as epoxy polysiloxane resins, and the like. An epoxy compound or epoxy resin having two or more epoxy groups is preferred.

The amount of the epoxy compound or epoxy resin used in the component (E) can be blended within a range that maintains the alkali-soluble properties of the white photosensitive resin composition, and is higher than that of the components (A) and (B). A total of 100 parts by mass can be prepared in a range of 5 to 30 parts by mass.

In addition, in the white photosensitive resin composition of the present invention, a hardening accelerator, an antioxidant, a thermal polymerization inhibitor, a plasticizer, a filler, a solvent, a leveling agent, a defoaming agent, a coupling agent, and an interface may be added as necessary. Additives such as active agents. Examples of thermal polymerization inhibitors include hydroquinone, hydroquinone monomethyl ether, pyrrogallol, tertiary butyl catechol, and phenolthiol. (phenothiazine), etc., the antioxidants can be hindered phenol-based antioxidants, phosphorus-based processing heat stabilizers, plasticizers can be dibutyl phthalate, dioctyl phthalate, tricresyl phosphate (tricresyl phosphate), etc., filled Examples of the material include glass fiber, silicon dioxide, mica, and alumina, and examples of the defoaming agent or leveling agent include silicone, fluorine, and acrylic compounds. In addition, examples of the surfactant include fluorine-based surfactants and polysiloxane-based surfactants. Examples of the silane coupling agent include 3- (glycidyloxy) propyltrimethoxysilane and 3-isocyanatepropyltriethyl. Oxysilane, 3-ureapropyltriethoxysilane, etc.

The white hardened | cured material of this invention is formed using the white photosensitive resin composition of this invention, and transmitted by the light lithography method. For its manufacturing steps, First, a white photosensitive resin composition solution containing a solvent is coated on the surface of the substrate, and then the solvent is dried (pre-baked). Then, the obtained coating film is irradiated with ultraviolet rays through a light mask to harden the exposed portion, and an alkali is further used. A non-exposed part is developed by developing an aqueous solution, developing it, forming a pattern, and further performing post-baking as a method of post-hardening. Here, as the substrate for coating the white photosensitive resin composition, glass, a transparent film (for example, polycarbonate, polyethylene terephthalate, polyether fluorene, and the like) can be used.

The method for applying the white photosensitive resin composition to the substrate may be any method such as a roll coater, a land coater, a slit coater, or a spinner, in addition to the known solution dipping method and spray coating method. method. After coating with a desired thickness by these methods, the solvent is removed (pre-baking) to form a coating film. The pre-baking is performed by heating in an oven, a hot plate, or the like. The heating temperature and heating time of the pre-baking are appropriately selected according to the solvent to be used, for example, it is performed at a temperature of 60 to 110 ° C. for 1 to 3 minutes.

The exposure performed after the pre-baking is performed by an exposure machine and is exposed through a light mask to expose only the photosensitive resin composition in a portion corresponding to the pattern. The exposure machine and its exposure irradiation conditions are appropriately selected, and exposure is performed using light sources such as an ultra-high pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, a far-ultraviolet lamp, and the photosensitive resin composition in the coating film is light hardened.

The alkali development after exposure is performed for the purpose of removing the photosensitive resin composition of the unexposed part, and a desired pattern is formed by this development. The developer suitable for this alkali development includes, for example, an alkali metal or alkaline earth metal carbonate aqueous solution, an alkali metal hydroxide aqueous solution, and the like, and it is particularly preferable to use a carbonate containing 0.03 to 1% by mass of sodium carbonate and potassium carbonate. of The weakly alkaline aqueous solution is developed at a temperature of 23 to 27 ° C, and a fine image can be precisely formed using a commercially available developing machine or an ultrasonic cleaner.

After developing in this manner, heat curing treatment (post-baking) is performed at a temperature of 200 to 240 ° C for 20 to 60 minutes. Thereafter, the baking is performed for the purpose of improving the adhesion between the patterned white film and the substrate. This is the same as pre-baking, and is performed by heating with an oven, a hot plate, or the like. The patterned white hardened material of the present invention is formed through each step of the photolithography method described above.

The white photosensitive resin composition of the present invention can be patterned by photolithography, and in particular, a cured product having excellent developing characteristics and excellent light discoloration resistance can be obtained.

Hereinafter, the present invention will be described in more detail through examples, but the present invention is not limited thereto.

[Example]

Hereinafter, the present invention will be described in more detail based on a synthesis example of a polymerizable unsaturated group-containing basic soluble resin as the component (A). The present invention is not limited to the scope of these synthesis examples and the like. In addition, the resins in the following synthesis examples were evaluated in the following manner unless otherwise specified.

〔Solid content concentration〕

A glass filter [weight: W ₀ (g)] was impregnated with 1 g of the resin solution obtained in the synthesis example, and [W ₁ (g)] was weighed. After heating at 160 ° C. for 2 hours, the weight was determined by the following formula. [W ₂ (g)].

Solid content concentration (% by weight) = 100 × (W ₂ -W ₀ ) / (W ₁ -W ₀ ).

[Acid value]

Dissolve the resin solution in two The alkane was titrated with a 1/10 N-KOH aqueous solution using a potentiometric titration device [trade name COM-1600 manufactured by Hiranuma Industry Co., Ltd.] to obtain the amount of KOH necessary as 1 g per solid content as the acid value.

[Molecular weight]

Gel permeation chromatography (GPC) [Tosoh Co., Ltd. trade name HLC-8220GPC, solvent: tetrahydrofuran, column: TSKgelSuperH-2000 (2) + TSKgelSuperH-3000 (1) + TSKgelSuperH-4000 (1 Root) + TSKgelSuper-H5000 (1) [manufactured by Tosoh Co., Ltd.], temperature: 40 ° C, speed: 0.6 ml / min], measured with standard polystyrene [PS-oligomer kit by Tosoh co., Ltd.] ] Converted value to obtain a weight average molecular weight (Mw).

The abbreviations used in Synthesis Examples and Comparative Synthesis Examples are as follows.

MAA: methacrylic acid

MMA: methyl methacrylate

CHMA: cyclohexyl methacrylate

GMA: glycidyl methacrylate

AIBN: Azobisisobutyronitrile

TPP: Triphenylphosphine

DTBC: 2,6-di-third-butyl-p-cresol

DMDG: Diethylene glycol dimethyl ether

PGMEA: propylene glycol monomethyl ether acetate

[Synthesis Example 1]

In a 1000 ml four-necked flask with a nitrogen introduction tube and a reflux cooler, add MAA 51.65g (0.60mol), MMA 38.44g (0.38mol), CHMA 36.33g (0.22mol), AIBN 5.91g and DMDG 368g, at 80 It was polymerized by stirring at 85 ° C for 8 hr under a nitrogen flow. Furthermore, 39.23 g (0.28 mol) of GMA, 1.44 g of TPP, and 0.055 g of DTBC were added to the flask, and the mixture was stirred at 80 to 85 ° C for 16 hours to obtain a (meth) acrylate resin (A) -1 containing a polymerizable unsaturated group. . The solid content concentration of the obtained resin solution was 32% by mass, the acid value (in terms of solid content) was 110 mgKOH / g, and the weight average molecular weight (Mw) by GPC analysis was 18080.

(Preparation of white photosensitive resin composition solution)

The white photosensitive resin composition solutions of Examples 1 to 2 and Comparative Example 1 were prepared according to the compositions shown in Table 1. The components used in the formulation are as follows. In addition, the numerical value in Table 1 is represented by mass%.

(A) Alkali soluble resin solution containing a polymerizable unsaturated group:

(A) -1 Resin solution of Synthesis Example 1

(A) -2 Bifunctional urethane acrylate oligomer containing carboxylic acid (resin solid content concentration: 53% by mass, trade name DAUA-167 manufactured by Kyoeisha Chemical Co., Ltd.)

(B) Photopolymerizable monomer: dipentaerythritol hexaacrylate (trade name DPHA manufactured by Nippon Kayaku Co., Ltd.)

(C) Photopolymerization initiator: 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoinoxime)] (trade name IRGACURE OXE01 manufactured by BASF)

(D) White light-shielding material: Titanium white (average particle size: 270 nm), a titanium white dispersion with a concentration of 73% by mass, and a propylene glycol monomethyl ether acetate solvent

(F) Solvent:

(F) -1: Propylene glycol monomethyl ether acetate

(F) -2: 3-methoxy-3-methylbutyl acetate

(G) Surfactant

(H) Silane coupling agent (1% propylene glycol monomethyl ether acetate solution)

(Evaluation of white photosensitive resin composition: developability)

The white photosensitive resin composition solutions of Examples 1 to 2 and Comparative Example 1 were coated and dried on a glass plate having a thickness of 1.2 mm and degreased and washed using a spin coater to obtain a dry film thickness of 10 μm, and dried. It was made to be in close contact with a photomask, and a 500W high-pressure mercury lamp was irradiated with ultraviolet light having a wavelength of 365nm and an illuminance of 10 mW / cm ² for 10 seconds. After exposure, a 0.4% sodium carbonate aqueous solution was used to develop at 23 ° C. and a pressure of 0.1 MPa at 60 sec to remove the unexposed portion of the coating film. Thereafter, a hot-air dryer was used to heat-harden at 230 ° C. for 30 minutes to obtain a white color. Film pattern (hardened material). Then, the white film pattern formed on the glass plate was confirmed with a microscope, and evaluation of pattern formation was performed based on the following. The results are shown in Table 2.

． Pattern formation

○: Patterns can be formed (line and pitch patterns of 5 to 30 μm remain)

×: Insoluble in developer or pattern peel

(Evaluation of white photosensitive resin composition: light discoloration resistance)

The white photosensitive resin composition solutions of Examples 1 to 2 and Comparative Example 1 were coated and dried on a glass plate having a thickness of 1.2 mm and degreased and washed using a spin coater to obtain a dry film thickness of 10 μm, and dried. Without using a photomask, the entire surface of the same white film as the glass plate was formed, and a 500W high-pressure mercury lamp was used to irradiate ultraviolet rays with a wavelength of 365nm and an illuminance of 10mW / cm ² for 10 seconds. After the exposure, the developer was treated with a 0.4% sodium carbonate aqueous solution at 23 ° C. for 60 seconds at a pressure of 0.1 MPa. Then, it heat-hardened at 230 degreeC using the hot-air dryer for 30 minutes. In order to confirm light discoloration resistance, a low-pressure mercury lamp was further irradiated with ultraviolet rays having an illuminance of 130 W / cm ² at a wavelength of 254 nm for 2 hours, and the b * value was measured by a spectrophotometer. The results are shown in Table 2.

From the results of Examples 1 to 2 and Comparative Example 1 shown above, it is clear that if it is a white photosensitive resin composition containing a basic soluble resin (A) -1 containing a polymerizable unsaturated group, it can be obtained A white hardened material that can form a pattern and has a good b * value. In addition, when the b * value exceeds 1.5, yellow discoloration becomes prominent, and it becomes unsuitable as a white hue, and light discoloration resistance becomes insufficient.

[Industrial availability]

The white photosensitive resin composition of the present invention can form a white film having excellent light discoloration resistance. Furthermore, since a pattern can be formed by photolithography, there is an advantage that it can be formed using an existing photolithography step. Furthermore, since it can be formed by a thin film, it can contribute to the thinning of the structure and is suitable for forming a touch panel. Made of white film.

Claims (5)

A white photosensitive resin composition comprising a copolymer (A) having 20 to 90 mole% of repeating units represented by the following general formula (1), and 5 to 50 moles of repeating units having an alicyclic structure. And the repeating units derived from the polymerizable unsaturated compounds copolymerizable with these copolymers are 5 to 50 mole%, and the copolymer (A) has a weight average molecular weight of 10,000 to 100,000 and an acid value of 35 to 120mgKOH / g; photopolymerizable monomer (B) having at least one ethylenically unsaturated bond; photopolymerization initiator (C); and white light-shielding material (D); wherein, it contains a solid after photocuring The proportion of the solid component of the monomer component in the solid component is (A) 1 to 55% by mass relative to 100 parts by mass of (A) and 10 to 100 parts by mass relative to (A) ) And (B) are 100 parts by mass in total, (C) is 0.1 to 40 parts by mass, in the solid content, (D) is 1 to 95% by mass, and in the solid content, (A) to (D) components Contains more than 70% by mass; In the formula, R ¹ and R ² each independently represent a hydrogen atom or a methyl group. The white photosensitive resin composition according to item 1 of the scope of patent application, wherein the component (A) is composed of a repeating unit group not containing an aromatic ring only. The white photosensitive resin composition according to item 1 or 2 of the patent application scope, further comprising an epoxy compound or an epoxy resin (E). A hardened product is obtained by patterning a white photosensitive resin composition according to any one of claims 1 to 3 in a patent application scope by a photolithography method and then thermally curing the white photosensitive resin composition. A touch panel includes a hardened object as described in item 4 of the scope of patent application.