JP2015172716A - White photosensitive resin composition, hardened product using the composition and touch panel containing the hardened product as constituent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a white resin composition which is excellent in developing characteristics while having sufficient light discoloration resistance, a hardened product using the composition and a touch panel containing the hardened product as a constituent.SOLUTION: A white photosensitive resin composition comprises (A) a specified alkali-soluble resin, (B) a photopolymerizable monomer having at least one ethylenic unsaturated bond, (C) a photopolymerization initiator and (D) a white light-shielding material. In the monomer-containing solid content after photo-curing, the content of (A) is 1-55 mass%; the content of (B) is 10-100 pts. mass relative to 100 pts. mass of (A); the content of (C) is 0.1-40 pts. mass relative to 100 pts. mass of the combined content of (A) and (B); and the content of (D) is 1-95 mass%. A hardened product obtained by pattering the white photosensitive resin composition through photolithography and subsequently hardening thermally and a touch panel having the hardened product are also provided.

Description

  The present invention relates to a white photosensitive resin composition capable of forming a desired pattern and having excellent light discoloration resistance. Specifically, the present invention relates to a white photosensitive resin composition and a cured product using the same. This hardened | cured material can be used as a white material for decorating a touchscreen, and relates to the touchscreen which uses this hardened | cured material as a structural component.

  In recent years, with the trend toward diversification of information equipment and the reduction in size and weight of mobile terminals, input displays that have been integrated with flat displays such as liquid crystal display panels, such as mobile phones, mobile information terminals, car navigation systems, etc. Integrated touch panel flat displays have become popular in the market. There are various types of touch panels such as a resistance film type and a capacitance type depending on the structure and detection method. Among these, the capacitive touch panel has a translucent conductive film (translucent electrode) on a single substrate, and has a capacitance formed by contact (touch) with a finger or a pen. The position to be touched is specified by detecting a change in the amount of weak current flowing through it, and the liquid crystal display device or the like is driven by receiving the instructed content as an input signal. The capacitive touch panel has an advantage that higher transmittance can be obtained as compared with the resistive touch panel.

  In any of the touch panels, a transparent protective plate such as a cover glass is usually used on the upper surface for detecting an input signal or protecting the screen. Therefore, a transparent protective plate is provided on the upper surface of the touch panel, or the transparent protective plate itself constitutes the touch panel. Some transparent protective plates include functional films such as a low reflection film, an antiglare film, a hard coat film, and an electromagnetic shield film.

  In recent years, with the trend toward fashion of electronic devices, decorations such as shielding of LCD wiring are generally applied by various printing methods on transparent protective plates of mobile terminal devices such as mobile phones. For example, Patent Document 1 and Patent Document 2 include a protective panel in which a decorative film in which a window forming layer having a transparent window portion is formed in advance on the back surface of a hard coat film is attached to a transparent protective plate surface in a laminated state. The transparent protective plate is bonded to the movable electrode film at a peripheral portion so as to form an air layer between the movable electrode film laminated with a decorative film and the movable electrode film. An electronic device configured by a touch panel including the fixed electrode plate is disclosed. Conventionally, as described above, the decorated transparent protective plate and the touch panel are generally formed separately and combined in a later step. However, in recent years, there is a strong need for thinning mobile phones, and the number of processes can be reduced by forming a touch panel directly on the decorative transparent protective plate. A method using a photosensitive resin is attracting attention. A touch panel manufacturing method using this method is described in Patent Document 3. Black is generally used as the color of the decorative portion of the decorative transparent protective plate for touch panels, but with the trend toward electronic fashion, white decoration is required.

  However, particularly in the case of a white photosensitive resin, discoloration may occur due to heat applied when the coating film is heated and cured or in the process of manufacturing the touch panel, and the light reflectance may be reduced. Moreover, when light resistance is insufficient, it will color while using a touch panel, or a light reflectance will fall. In the case of a white photosensitive resin for a touch panel, since discoloration and a decrease in reflectance are particularly conspicuous, there is a possibility that the commercial value may be lowered, and a solution is required.

JP 2007-279756 A JP 2007-323092 A JP 2013-8272 A

  Accordingly, an object of the present invention is to solve the above-mentioned problems in the prior art, and have a sufficient light-discoloration resistance and a white photosensitive resin composition excellent in development characteristics, a cured product using the same, and the cured product It is providing the touch panel which uses as a structural component.

  As a result of diligent research to solve the above-mentioned problems, the present inventors have found that the copolymer (A), which is a polymerizable unsaturated group-containing alkali-soluble resin having a specific structure, a photopolymerizable monomer (B ), A photopolymerization initiator (C), and a white photosensitive resin composition containing a white light-shielding material (D) can form a pattern with light and obtain a cured product having excellent light discoloration resistance. It was found that it is useful for decorating touch panels. That is, the gist of the present invention is as follows.

（ただし、Ｒ^１及びＲ^２は、それぞれ独立に水素原子又はメチル基を表す。） (1) In the present invention, the repeating unit represented by the following general formula (1) is 20 to 90 mol%, the repeating unit having an alicyclic structure is 5 to 50 mol%, and the polymerizable property copolymerizable therewith. A copolymer (A) having 5 to 50 mol% of a repeating unit derived from an unsaturated compound, a weight average molecular weight of 10,000 to 100,000, and an acid value of 35 to 120 mgKOH / g, at least 1 It is a white photosensitive resin composition containing a photopolymerizable monomer (B) having a single ethylenically unsaturated bond, a photopolymerization initiator (C), and a white light-shielding material (D). (A) is 1-55 mass% in the ratio in the solid content containing the monomer component which becomes (B) is 10-100 mass parts with respect to (A) 100 mass parts, (A) and (C) is 0.1-40 mass with respect to 100 mass parts of total amount of (B). , And the and (D) is a white light-sensitive resin composition characterized in that it is contained 1 to 95% by weight.

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

  (2) The present invention is also the white photosensitive resin composition according to (1), wherein the component (A) is composed only of a repeating unit group containing no aromatic ring.

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

  (5) The present invention is also a touch panel having the cured product of (4).

  The present invention is described in detail below.

（ただし、Ｒ^１及びＲ^２は、それぞれ独立に水素原子又はメチル基を表す。） The copolymer (A) in the white photosensitive resin composition of the present invention comprises (i) 20 to 90 mol% of a repeating unit represented by the following general formula (1), and (ii) a repeating unit having an alicyclic structure. 5 to 50 mol%, and (iii) 5 to 50 mol% of repeating units derived from a polymerizable unsaturated compound copolymerizable therewith, and a weight average molecular weight of 10,000 to 100,000, and It is a polymerizable unsaturated group-containing alkali-soluble resin having an acid value of 35 to 120 mgKOH / g.

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

  The component (A) is preferably based on 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 hereinafter). In radical polymerization, known radical polymerization initiators such as azo compounds and peroxides can be used, and the degree of polymerization may be controlled using a known chain transfer agent or polymerization inhibitor. In addition, 20 to 90 mol% of repeating units represented by the general formula (1) means that the repeating units represented by the general formula (1) with respect to the total number of repeating units constituting the copolymer (A). It shows that the ratio of the number of units is 20 to 90 mol%. Hereinafter, the repeating unit may be 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 used as a raw material, and this is directly radically polymerized. In order to prevent gelation, a polymer or copolymer having a unit derived from (meth) acrylic acid is added with glycidyl (meth) acrylate, or a polymer having a unit derived from glycidyl (meth) acrylate is used. It is preferable to use a two-step synthesis method in which (meth) acrylic acid is added to a polymer or copolymer. 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.

  The component (A) has 5 to 50 mol% of units having an alicyclic structure in addition to the unit represented by the general formula (1). 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 preferable because it is simple. Examples of polymerizable unsaturated compounds having an alicyclic structure include cyclopropyl (meth) acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, dimethacrylate (meth) acrylate. Examples include cyclopentanyl, dicyclopentenyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, and the like. There is also a method obtained by reacting a polymer or copolymer having a unit derived from (meth) acrylic acid with an alcohol, amine or epoxy compound having an alicyclic structure.

  The unit having an alicyclic structure may be any unit having at least one alicyclic structure, a structure in which a hydrocarbon group is branched from the alicyclic structure, and a halogen atom, Hydroxy group, sulfanyl group, carbonyl group, thiocarbonyl group, carboxy group, thiocarboxy group, dithiocarboxy group, formyl group, cyano group, nitro group, nitroso group, sulfo group, amino group, imino group, silyl group, ether group , A thioether group, an ester group, a thioester group, a dithioester group, an amide group, a thioamide group, a urethane group, a thiourethane group, a ureido group, a thioureido group, and the like may be introduced.

  Furthermore, (A) component has 5-50 mol% of units derived from the polymerizable unsaturated compound copolymerizable with the unit represented by the general formula (1) and the unit having the alicyclic structure. That is, the (A) component can be copolymerized with any unit other than the unit represented by the general formula (1) and the unit having an alicyclic structure, for example, (meth) acrylic acid, (meth) acrylic acid Units derived from esters, (meth) acrylic amides, styrene and derivatives thereof, maleic anhydride and derivatives thereof, vinyl ethers, olefins and the like can be introduced. Only one type or two or more units derived from this copolymerizable polymerizable unsaturated compound may be used, but the total unit when two or more types are used is preferably 5 to 50 mol%. . Here, from the viewpoint of light resistance, it is advantageous to use a compound that does not absorb as much as possible in the ultraviolet light region. Therefore, the component (A) is preferably composed only of a unit group that does not contain 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, vinyl, allyl, ethynyl Group, phenyl group, tolyl group, mesityl group, naphthyl group, anthryl group, phenanthryl group, benzyl group, 2-phenylethyl group, 2-phenylvinyl group, etc., saturated or unsaturated monovalent hydrocarbon group, pyridyl Group, piperidyl group, piperidino group, pyrrolyl group, pyrrolidinyl group, imidazolyl group, imidazoli Examples thereof include saturated or unsaturated monovalent heterocyclic groups such as a dinyl group, a furyl group, a tetrahydrofuryl group, a thienyl group, a tetrahydrothienyl group, a morpholinyl group, a morpholino group, and a 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 group having 1 to 20 carbon atoms. It is preferably a hydrocarbon group, more preferably a saturated or unsaturated monovalent hydrocarbon group having 1 to 6 carbon atoms (however, these do not include an alicyclic structure). R ⁴ and R ⁵ may be a hydrogen atom, or R ⁴ and R ⁵ may be bonded to form a ring.

  In addition to the above, units having an epoxy group [eg, units derived from (meth) acrylic acid glycidyl, (meth) acrylic acid [4- (glycidyloxy) butyl], 4- (glycidyloxymethyl) styrene, etc.] , Units having an alkoxysilyl group [for example, (meth) acrylic acid [3- (trimethoxysilyl) propyl], (meth) acrylic acid [3- (triethoxysilyl) propyl], 4- (trimethoxysilyl) styrene, etc. The unit derived from is also preferred as a 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. In addition, the alkyl as used in this paragraph represents a C1-C20 saturated or unsaturated hydrocarbon group, and such a hydrocarbon group may have a branched structure or may be substituted with an arbitrary substituent. Good.

  The component (A) needs to contain 20 to 90 mol% of the unit represented by the general formula (1), preferably 25 to 75 mol%, more preferably 30 to 60 mol%. When the number of units represented by the general formula (1) is less than this, the adhesion of the white photosensitive resin composition is 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%. Moreover, (A) component needs to contain 5-50 mol% of units which have an alicyclic structure, it is preferable to contain 7-40 mol%, and it is more preferable to contain 10-30 mol%. A unit having an alicyclic structure improves light resistance.

  The weight average molecular weight of the component (A) needs to be in the range of 10,000 to 100,000, and more preferably in the range of 15,000 to 50,000. When the weight average molecular weight is smaller than this, the adhesion of the white photosensitive resin composition is insufficient, and when the weight average molecular weight is larger, image formation by photolithography becomes difficult.

（ただし、Ｒ^１及びＲ^２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) needs to be 35 to 120 mgKOH / g, and 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. Although the acid value can be imparted to the component (A) by typically copolymerizing units derived from (meth) acrylic acid at a predetermined molar ratio, it is represented by the following general formula (2). Also preferred is the introduction of units. 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). The unit represented by the general formula (2) is derived from the polymerizable unsaturated compound (iii) that can be copolymerized with the unit represented by the general formula (1) or the unit having the alicyclic structure. In the case where the component (A) contains this, the unit represented by the general formula (2) is replaced with a unit derived from the polymerizable unsaturated compound (iii) (A) It is preferable to contain in the range of 10-30 mol% in the copolymer of this.

(However, 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.)

  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 unit of the general formula (2), (meth) acrylic acid ester having a hydroxy group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate A unit derived from a structure obtained by adding a dicarboxylic anhydride, a unit derived from maleic anhydride and a derivative thereof, and the like can be used as a unit derived from the polymerizable unsaturated compound (iii).

  The reason why the component (A) is suitable for the white photosensitive resin composition is not always clear, but the polymerizable unsaturated bond at the terminal of the unit represented by the general formula (1) forms a dense cross-linked structure after curing. Since it includes a unit having an alicyclic structure effective for improving light resistance, it is presumed that a cured film suitable for touch panel applications can be formed. Moreover, about (A) component, it can use combining 2 or more types of copolymers from which a composition differs. This component (A) is contained in an amount of 1 to 55% by mass and preferably 3 to 50% by mass in the solid content of the white photosensitive resin composition. Here, the solid content includes a monomer component that becomes a solid content after photocuring included in the white photosensitive resin composition, and does not include a solvent.

  Examples of the photopolymerizable monomer (B) having at least one ethylenically unsaturated bond in the white photosensitive resin composition of the present invention include 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth). (Meth) acrylic acid esters having a hydroxyl group such as acrylate and 2-ethylhexyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol Di (meth) acrylate, tetramethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pen Erythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, glycerol (meth) acrylate, sorbitol penta (meth) acrylate, dipentaerythritol penta (meth) acrylate, or dipentaerythritol (Meth) acrylic esters such as hexa (meth) acrylate, sorbitol hexa (meth) acrylate, alkylene oxide-modified hexa (meth) acrylate of phosphazene, caprolactone-modified dipentaerythritol hexa (meth) acrylate, and dendrimer type polyfunctional acrylate 1 type or 2 types or more of these can be used. The photopolymerizable monomer having at least one ethylenically unsaturated bond has two or more photopolymerizable groups and crosslinks the molecules of the unsaturated group-containing alkali-soluble resin [component (A)]. It is preferable to use what can be used. Note that (B) the photopolymerizable monomer having at least one ethylenically unsaturated bond does not have a free carboxy group.

  Examples of the photopolymerization initiator (C) in the white photosensitive resin composition of the present invention include acetophenone, 2,2-diethoxyacetophenone, P-dimethylacetophenone, P-dimethylaminopropiophenone, dichloroacetophenone, and trichloroacetophenone. Acetophenones such as P-TERT-butylacetophenone, benzophenone, 2-chlorobenzophenone, benzophenones such as P, P′-bisdimethylaminobenzophenone, benzyl, benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether, etc. Benzoin ethers, 2- (O-chlorophenyl) -4,5-phenylbiimidazole, 2- (O-chlorophenyl) -4,5-di (M-methoxyphenyl) biimidazole , 2- (O-fluorophenyl) -4,5-diphenylbiimidazole, 2- (O-methoxyphenyl) -4,5-diphenylbiimidazole, biimidazole series such as 2,4,5-triarylbiimidazole, etc. Compounds, 2-trichloromethyl-5-styryl-1,3,4-oxadiazol, 2-trichloromethyl-5- (P-cyanostyryl) -1,3,4-oxadiazole, 2-trichloromethyl Halomethylthiazole compounds such as -5- (P-methoxystyryl) -1,3,4-oxadiazole, 2,4,6-tris (trichloromethyl) -1,3,5-triazine, 2-methyl -4,6-bis (trichloromethyl) -1,3,5-triazine, 2-phenyl-4,6-bis (trichloromethyl) -1,3,5-triazine, -(4-Chlorophenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -1,3,5- Triazine, 2- (4-methoxynaphthyl) -4,6-bis (trichloroRmethyl) -1,3,5-triazine, 2- (4-methoxystyryl) -4,6-bis (trichloromethyl) -1 , 3,5-triazine, 2- (3,4,5-trimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-methylthiostyryl) -4, Halomethyl-S-triazine compounds such as 6-bis (trichloromethyl) -1,3,5-triazine, 1,2-octanedione, 1- [4- (phenylthio) phenyl]-, 2- (O— Benzoylo Oxime), 1- (4-phenylsulfanylphenyl) butane-1,2-dione-2-oxime-O-benzoate, 1- (4-methylsulfanylphenyl) butane-1,2-dione-2-oxime O-acyloxime compounds such as -O-acetate, 1- (4-methylsulfanylphenyl) butan-1-oneoxime-O-acetate, benzyldimethyl ketal, thioxanthone, 2-chlorothioxanthone, 2,4- Sulfur compounds such as diethylthioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, anthraquinones such as 2-ethylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-diphenylanthraquinone, azo Bisisobutylnitrile, benzoylper Side, organic peroxides such as cumene peroxide, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, thiol compounds such as 2-mercaptobenzothiazole, triethanolamine, etc. tertiary amines such as triethylamine and the like. Among these, it is preferable to use O-acyloxime compounds from the viewpoint of easily obtaining a highly sensitive white photosensitive resin composition. Two or more of these photopolymerization initiators can also be used. In addition, the photoinitiator as used in the field of this invention is used by the meaning containing a sensitizer.

Examples of the (D) white light shielding material in the white photosensitive resin composition of the present invention include white organic pigments and white inorganic pigments. Examples of the white organic pigment include organic compound salts of the general formula A ^n- n [B] disclosed in JP-A-11-129613 (A is a substituted stilbene fluorescent whitening agent having an anionic group and a sulfonic acid group, substituted Fluorescent brightener components such as coumarin fluorescent brighteners and substituted thiophene fluorescent brighteners, B is an organic cation such as ammonium or pyridinium having 15 or more carbon atoms, and n is an integer of 1 to 9) And white organic pigments such as alkylene bismelamine derivatives such as ethylene bismelamine and N, N′-dicyclohexylethylene bismelamine disclosed in JP-A No. 6-122647 (commercially available products include Shigenox OWP, Shigenox OWPL (Hackol Chemical Co., Ltd.). ))), Hollow particles using thermoplastic resins described in JP-A-2008-1072, for example, styrene-acrylic Hollow particles comprising a alcohol copolymer, crosslinked styrene - (Commercial products, SX866, SX8782 (JSR Corporation)) hollow particles comprising acrylic copolymer and the like.

  Examples of white inorganic pigments include chromium oxide, iron oxide, titanium oxide, titanium white, titanium oxynitride, and titanium nitride. These light shielding materials, including white organic pigments and white inorganic pigments, can be used alone or in appropriate selection of two or more, and in particular, titanium white has light shielding properties, surface smoothness, The dispersion stability and the affinity with the resin are preferable. Moreover, the average particle diameter (volume average particle diameter measured by a laser diffraction / scattering particle diameter measuring device) of the white organic pigment or white inorganic pigment used is preferably 20 to 1000 nm, more preferably 50 to 700 nm. preferable.

  In addition, the white photosensitive resin composition of the present invention may be used in combination with a colored ink or a colored inorganic pigment without particular limitation in order to change the color to gray, pink, etc. according to the use or to adjust the light shielding property. Can do. Examples of the colored inorganic pigment used in combination include carbon black, chromium oxide, iron oxide, titanium oxide, titanium black, titanium oxynitride, and titanium nitride. For the purpose of adjusting the light shielding property, a black light shielding layer and a two-layer structure can 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 thereon using a black photosensitive resin composition.

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

  About the component ratio of each component of (A)-(D) in white photosensitive resin composition, (A) is 1-55 in the ratio in the solid content containing the monomer component used as solid content after photocuring. (B) is 10 to 100 parts by mass, preferably 30 to 50 parts by mass with respect to 100 parts by mass (A), and (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 with respect to 100 parts by mass of the total amount. The

  (A) When (B) is less than 10 parts by mass with respect to 100 parts by mass, the solubility of the coating film in the developer becomes too low, so that the photolithography performance is deteriorated. On the other hand, when (B) exceeds 100 parts by mass with respect to (A) 100 parts by mass, the solubility of the film in the developer becomes too high, so that the adhesion of the coating film during development decreases.

  When (C) 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 is not cured, and when it exceeds 40 parts by mass, an area larger than the mask opening area is obtained. Since it hardens | cures, photolithography performance falls.

  When (D) is less than 1% by mass in the solid content, the coloring power is remarkably lowered, and when it is more than 95% by mass, the viscosity of the ink is increased and coating of the film becomes difficult.

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

  In the white photosensitive resin composition of this invention, it is preferable to adjust a viscosity using a solvent other than said (A)-(D), and to set it as a white photosensitive resin composition solution. Examples of the solvent include alcohols such as methanol, ethanol, N-propanol, isopropanol, ethylene glycol, and propylene glycol, terpenes such as α- or β-terpineol, acetone, methyl ethyl ketone, cyclohexanone, N-methyl-2- Ketones such as pyrrolidone, aromatic hydrocarbons such as toluene, xylene, tetramethylbenzene, cellosolve, methyl cellosolve, ethyl cellosolve, carbitol, methyl carbitol, ethyl carbitol, butyl carbitol, propylene glycol monomethyl ether, propylene Glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monomethyl ether, Glycol ethers such as reethylene glycol monoethyl ether, ethyl acetate, butyl acetate, cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, propylene glycol mono Examples thereof include acetic esters such as ethyl ether acetate and 3-methoxy-3-methylbutyl acetate, and by dissolving and mixing them, a uniform solution-like composition can be obtained. Although the quantity of a solvent changes with target viscosity, the range of 60-90 mass% in a white photosensitive resin composition solution is preferable.

  In the present invention, in addition to the components (A) to (D), a white photosensitive resin composition containing (E) an epoxy compound or an epoxy resin can be used, but this (E) is used as the epoxy compound or epoxy resin. Examples of the compound include phenyl glycidyl ether, p-butylphenol glycidyl ether, triglycidyl isocyanurate, diglycidyl isocyanurate, allyl glycidyl ether, glycidyl methacrylate and other epoxy compounds, bisphenol A type epoxy resin, bisphenol F type epoxy resin, 3 , 3 ', 5,5'-tetramethyl-4,4'-biphenol type epoxy resin, bisphenol type epoxy resin such as bisphenol fluorene type epoxy resin, phenol novolac type epoxy resin, novolat such as cresol novolac type epoxy resin Type epoxy resins, glycidyl ether of polyhydric alcohol, glycidyl ester of polycarboxylic acid, 3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxycyclohexenecarboxylate, 2,2-bis (hydroxymethyl) Examples include alicyclic epoxy compounds such as 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 1-butanol, and epoxy resins having a silicone skeleton such as epoxy silicone resin. Preferably, it is an epoxy compound or epoxy resin having two or more epoxy groups.

  The amount of the epoxy compound or epoxy resin used as the component (E) is preferably blended within the range in which the alkali-soluble property of the white photosensitive resin composition is maintained. The components (A) and (B) It is good to mix | blend in the range of 5-30 mass parts with respect to a total of 100 mass parts.

  Further, the white photosensitive resin composition of the present invention includes a curing accelerator, an antioxidant, a thermal polymerization inhibitor, a plasticizer, a filler, a solvent, a leveling agent, an antifoaming agent, a coupling agent, if necessary. Additives such as surfactants can be blended. Examples of thermal polymerization inhibitors include hydroquinone, hydroquinone monomethyl ether, pyrogallol, TERT-butylcatechol, phenothiazine, etc., and examples of antioxidants include hindered phenol antioxidants and phosphorus processing heat stabilizers. Examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, and tricresyl phosphate. Examples of the filler include glass fiber, silica, mica, alumina, and the like, and an antifoaming agent and a leveling agent. Examples thereof include silicone-based, fluorine-based, and acrylic compounds. Examples of the surfactant include a fluorine-based surfactant and a silicone-based surfactant. Examples of the silane coupling agent include 3- (glycidyloxy) propyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane. , 3-ureidopropyltriethoxysilane and the like.

  The white cured product of the present invention is formed by a photolithography method using the white photosensitive resin composition of the present invention. As the manufacturing process, first, a white photosensitive resin composition solution containing a solvent is applied to the surface of the substrate, then the solvent is dried (prebaked), and then a photomask is formed on the film thus obtained. And exposing the ultraviolet ray to cure the exposed portion, further developing with an alkaline aqueous solution to elute the unexposed portion to form a pattern, and further post-baking as post-curing. Here, as a substrate to which the white photosensitive resin composition solution is applied, glass, a transparent film (for example, polycarbonate, polyethylene terephthalate, polyether sulfone, etc.) or the like is used.

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

  The exposure performed after pre-baking is performed by an exposure machine, and only the photosensitive resin composition corresponding to the pattern is exposed by exposure through a photomask. The exposure machine and the exposure irradiation conditions are appropriately selected, and exposure is performed using a light source such as an ultra-high pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, or a deep ultraviolet lamp, and the photosensitive resin composition in the coating film is photocured.

  The alkali development after exposure is performed for the purpose of removing the photosensitive resin composition in the unexposed portions, and a desired pattern is formed by this development. Examples of the developer suitable for the alkali development include an aqueous solution of an alkali metal or alkaline earth metal carbonate, an aqueous solution of an alkali metal hydroxide, and the like. It is better to develop at a temperature of 23 to 27 ° C. using a weakly alkaline aqueous solution containing 0.03 to 1% by mass of carbonate, and fine images can be precisely obtained using a commercially available developing machine or ultrasonic cleaner. Can be formed.

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

  The white photosensitive resin composition of the present invention can be patterned by photolithography, and can provide a cured product that is particularly excellent in development characteristics and light discoloration resistance.

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

  Below, this invention is demonstrated further in detail based on the synthesis example etc. of polymerizable unsaturated group containing alkali-soluble resin which is (A) component. The scope of the present invention is not limited by these synthesis examples. Moreover, evaluation of the resin in the following synthesis examples was performed as follows unless otherwise noted.

[Solid content]
1 g of the resin solution obtained in the synthesis example was impregnated into a glass filter [weight: W ₀ (g)], weighed [W ₁ (g)], and heated at 160 ° C. for 2 hours [W ₂ ( g)] from the following equation.
Solid content concentration (% by weight) = 100 × (W ₂ −W ₀ ) / (W ₁ −W ₀ )

[Acid value]
A resin solution is dissolved in dioxane, and a potentiometric titrator (trade name COM-1 manufactured by Hiranuma Sangyo Co., Ltd.)
600) was titrated with a 1/10 N-KOH aqueous solution, and the amount of KOH required per gram of the solid content was defined as the acid value.

[Molecular weight]
Gel permeation chromatography (GPC) (HLC-8220GPC manufactured by Tosoh Corporation, solvent: tetrahydrofuran, column: TSKgelSuperH-2000 (2) + TSKgelSuperH-3000 (1) + TSKgelSuperH-4000 (1) + TSKgelSuper-H5000 ( 1) (manufactured by Tosoh Co., Ltd.), temperature: 40 ° C., speed: 0.6 ml / min)), and the weight average molecular weight (Mw) as standard polystyrene (PS-oligomer kit manufactured by Tosoh Co., Ltd.) ).

Abbreviations used in the 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-tert-butyl-p-cresol
DMDG: Diethylene glycol dimethyl ether
PGMEA: Propylene glycol monomethyl ether acetate

[Synthesis Example 1]
MAA 51.65 g (0.60 mol), MMA 38.44 g (0.38 mol), CHMA 36.33 g (0.22 mol), AIBN 5.91 g, and DMDG 368 g were charged into a 1000 ml four-necked flask equipped with a nitrogen inlet tube and a reflux tube, and 80 to 85 Polymerization was carried out by stirring for 8 hours under nitrogen flow at ℃. Further, 39.23 g (0.28 mol) of GMA, 1.44 g of TPP and 0.055 g of DTBC were charged into the flask and stirred at 80 to 85 ° C. for 16 hours to obtain a polymerizable unsaturated group-containing (meth) acrylate resin (A) -1. It was. The obtained resin solution had a solid content concentration of 32% by mass, an acid value (in terms of solid content) of 110 mgKOH / g, and a weight average molecular weight (Mw) by GPC analysis of 18080.

(Preparation of white photosensitive resin composition solution)
Compounding was carried out according to the composition shown in Table 1, and white photosensitive resin composition solutions of Examples 1-2 and Comparative Example 1 were prepared. Each component used for the blending is as follows. In addition, the numerical value in Table 1 represents mass%.
(A) Polymerizable unsaturated group-containing alkali-soluble resin solution:
(A) -1 Resin solution of Synthesis Example 1 (A) -2 Carboxylic acid-containing bifunctional urethane acrylate oligomer (resin solid content concentration 53 mass%, manufactured by Kyoeisha Chemical Co., Ltd., trade name DAUA-167)
(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-benzoyloxime)] (trade name Irgacure OXE01 manufactured by BASF)
(D) White light-shielding material: titanium white (average particle size 270 nm) concentration 73 mass%, titanium white dispersion of 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 and 2 and Comparative Example 1 were applied and dried on a degreased and washed 1.2 mm thick glass plate using a spin coater under conditions that resulted in a dry film thickness of 10 μm. Thereafter, a photomask was brought into close contact, and irradiation with ultraviolet rays having a wavelength of 365 nm and an illuminance of 10 mW / cm ² was performed for 10 seconds using a 500 W high-pressure mercury lamp lamp. After the exposure, development was performed with a 0.4% aqueous sodium carbonate solution at 23 ° C. for 60 seconds at a pressure of 0.1 MPa to remove the unexposed portion of the coating film, and then using a hot air dryer at 230 ° C. for 30 minutes. A heat curing treatment was performed to obtain a white film pattern (cured product). And the white film | membrane pattern formed on the glass plate was confirmed with the microscope, and the evaluation regarding pattern formation was performed according to the following. The results are shown in Table 2.
・ Pattern formation ○: Pattern can be formed (5 μm to 30 μm line & space pattern remains)
×: Not dissolved in developer or pattern peeling

(Evaluation of white photosensitive resin composition: light discoloration resistance)
The white photosensitive resin composition solutions of Examples 1 and 2 and Comparative Example 1 were applied on a degreased and washed 1.2 mm thick glass plate under a condition that a dry film thickness of 10 μm was obtained using a spin coater. After drying, the entire surface of the same white film-formed glass plate as described above was irradiated with ultraviolet light having a wavelength of 365 nm and an illuminance of 10 mW / cm ² for 10 seconds without using a photomask. After the exposure, a developer treatment was performed using a 0.4% aqueous sodium carbonate solution at 23 ° C. for 60 seconds at a pressure of 0.1 MPa. Thereafter, a heat curing treatment was performed at 230 ° C. for 30 minutes using a hot air dryer. In order to confirm the light discoloration resistance, ultraviolet light having an illuminance of 130 W / cm ² having a wavelength of 254 nm was further irradiated for 2 hours using a low-pressure mercury lamp, and the b ^* value was measured with a spectrophotometer. The results are shown in Table 2.

As is clear from the results of Examples 1-2 and Comparative Example 1 shown above, according to the white photosensitive resin composition containing the polymerizable unsaturated group-containing alkali-soluble resin (A) -1, pattern formation It was found that a white cured product having a good b ^* value can be obtained. Note that when the b ^* value exceeds 1.5, yellowing becomes remarkable, and the white color becomes inappropriate, and the light discoloration resistance is not sufficient.

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

Claims (5)

20 to 90 mol% of repeating units represented by the following general formula (1), 5 to 50 mol% of repeating units having an alicyclic structure, and repeating derived from a polymerizable unsaturated compound copolymerizable therewith A copolymer (A) having a unit of 5 to 50 mol%, a weight average molecular weight of 10,000 to 100,000, and an acid value of 35 to 120 mgKOH / g, at least one ethylenically unsaturated bond Is a white photosensitive resin composition containing a photopolymerizable monomer (B), a photopolymerization initiator (C), and a white light-shielding material (D), and a solid content containing a monomer component that becomes a solid content after photocuring In the ratio in, (A) is 1-55 mass%, (B) is 10-100 mass parts with respect to (A) 100 mass parts, and the total amount of (A) and (B) is 100. (C) is 0.1-40 mass parts with respect to mass parts, and ( ) White photosensitive resin composition characterized in that it is contained 1 to 95% by weight.

(However, R ¹ and R ² each independently represents a hydrogen atom or a methyl group.)   (A) The white photosensitive resin composition of Claim 1 comprised only from the repeating unit group in which a component does not contain an aromatic ring.   Furthermore, the white photosensitive resin composition of Claim 1 or 2 containing an epoxy compound or an epoxy resin (E).   Hardened | cured material obtained by patterning the white photosensitive resin composition in any one of Claims 1-3 by the photolithographic method, and carrying out subsequent thermosetting.   A touch panel having the cured product according to claim 4.