JP2016128554A - White thermosetting composition, decorative printing ink for blocking light, image display device, and method for manufacturing touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a white thermosetting composition that can give a cured film excellent in yellow discoloration resistance, acid resistance and alkali resistance when used for forming a decorative part of a touch panel, and to provide a white decorative printing ink that can give a decorative part excellent in yellow discoloration resistance, acid resistance and alkali resistance, an image display device having a decorative part having high yellow discoloration resistance, acid resistance, alkali resistance and heat resistance, and a method for manufacturing a touch panel having a white decorative part.SOLUTION: A white thermosetting composition comprises: as a component (A), a combination of a (meth)acrylic copolymer resin having an acetoacetoxy group and a (meth)acrylic copolymer resin having at least two hydroxyl groups in one molecule, or a (meth)acrylic copolymer resin having an acetoacetoxy group and a hydroxyl group in one molecule; a white pigment as a component (B); and a solvent as a component (C). The composition is cured by a methylolation reaction between the acetoacetoxy group and the hydroxyl group.SELECTED DRAWING: None

Description

  The present invention relates to a white curable composition used for decorative printing for shading of a touch panel such as a smartphone or a tablet PC, and an image display device formed from the white curable composition.

  In recent years, touch panels have been mounted on various electronic devices typified by smartphones and tablet PCs. A frame called a decorative portion is arranged on the outer peripheral portion of the glass surface of the touch panel. The decoration unit has a function of concealing the wiring of the touch panel and the wiring of the display device so that the wiring is not visually recognized.

  The decoration part is directly visible, so design is also important, and in the past it was often black, but recently there has been an increasing demand for white. In addition, the decorating part also has a light blocking function for preventing light leakage from the display device.

  As a type of touch panel, a capacitance method is generally used, and since a smaller number of members is required, a method called OGS (One Glass Solution) in which a touch panel function is provided on a cover glass is recently used. Yes. In the case of OGS, the decoration part is also exposed to high temperatures in the process of vapor deposition of transparent electrodes such as ITO in order to form a touch sensor on the cover glass, so the composition constituting the decoration part requires high heat resistance. Is done. In addition, the coating film also needs to have acid resistance and alkali resistance due to ITO etching and subsequent processing.

  Patent Document 1 proposes a curable resin composition using a carboxyl group-containing resin and a phosphinic acid metal salt for a printed wiring board. However, epoxy acrylate, polyurethane, or the like is used for the carboxyl group-containing resin, and the epoxy acrylate is yellowed at a high temperature because a catalyst such as phosphine or amine used for acrylate formation remains. Polyurethane has low heat resistance and may decompose at high temperatures. In addition, since phosphine is used as a curing catalyst, when such a composition is used, the coating film is yellowed in the high temperature process, which is difficult to use.

  Patent Document 2 proposes a thermosetting resin composition containing a polyimide resin for use in a printed wiring board. However, even when polyimide is used, the coating film turns yellow in the above high temperature process. It is difficult to use.

  Patent Document 3 discloses an epoxy resin composition comprising an epoxy resin and a copolymer containing styrene and maleic anhydride as components as an epoxy resin curing agent and an inorganic filler. The acid copolymer is also difficult to use because the coating film turns yellow in the high temperature step.

JP 2013-33282 A JP 2013-71969 A JP 2009-40832 A

  The present invention has been developed under the background art as described above, and its main purpose is heat yellowing resistance, acid resistance, when used as a white thermosetting composition for a decorative part of a touch panel, It is providing the curable composition which can obtain the cured film excellent in alkali resistance. Another object is to provide a white decorative printing ink capable of obtaining a decorative part excellent in heat yellowing resistance, acid resistance and alkali resistance, heat yellowing resistance, acid resistance, alkali resistance and heat resistance. The object is to provide a good decorative portion and to provide an image display device having the decorative portion.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have (meth) acrylic copolymer resin having an acetoacetoxy group as a white thermosetting composition and two or more hydroxyl groups in one molecule. Contains a (meth) acrylic copolymer resin or a (meth) acrylic copolymer resin having a acetoacetoxy group and a hydroxyl group in one molecule, a white pigment, and a solvent, and is cured by a methylolation reaction between the acetoacetoxy group and the hydroxyl group. The present inventors have found that by using a white thermosetting composition characterized in that a decorative part excellent in heat yellowing resistance, acid resistance and alkali resistance can be obtained, the present invention has been completed.

That is, the present invention (I) contains the following component (A), component (B) and component (C) as essential components and is cured by a methylolation reaction between an acetoacetoxy group and a hydroxyl group. It is a curable composition.
Component (A): (A-1) A combination of a (meth) acrylic copolymer resin having an acetoacetoxy group and a (meth) acrylic copolymer resin having two or more hydroxyl groups in one molecule, and (A-) 1 At least one selected from the group consisting of a (meth) acrylic copolymer resin having an acetoacetoxy group and a hydroxyl group in the molecule Component (B): White pigment Component (C): Solvent The present invention (II) is also an invention It is the decorative printing ink for light shielding of a touchscreen containing the white thermosetting composition of (I).
Furthermore, this invention (III) is an image display apparatus which has a decoration part formed using the decorative printing ink for light shielding of the touchscreen of this invention (II).
Further, the present invention (IV) is formed by applying the shading decorative printing ink of the touch panel of the present invention (II) to the outer peripheral portion of the glass surface of the touch panel and curing it at a temperature of 200 to 300 ° C. It is a manufacturing method of a touch panel which has a decoration part.

（式中、Ｒ^１は水素原子またはメチル基を示し、Ｒ^２は炭素数１〜４のアルキル基を示す。）
で表される単量体から誘導される構造を有する（メタ）アクリル共重合樹脂であることを特徴とする［１］〜［４］のいずれかに記載の白色熱硬化性組成物。
［６］成分（Ａ）が、ポリスチレン換算の質量平均分子量が５０００〜５００００である（メタ）アクリル共重合樹脂を含むことを特徴とする［１］〜［５］のいずれかに記載の白色熱硬化性組成物。
［７］成分（Ｂ）が酸化チタンであることを特徴とする［１］〜［６］のいずれかに記載の白色熱硬化性組成物。
［８］タッチパネルの加飾部をスクリーン印刷によって形成するために用いられる、［１］〜［７］のいずれかに記載の白色熱硬化性組成物。
［９］［１］〜［８］のいずれかに記載の白色熱硬化性組成物を含む、タッチパネルの遮光用加飾印刷インキ。
［１０］［９］に記載のタッチパネルの遮光用加飾印刷インキを用いて形成された加飾部を有する画像表示装置。
［１１］［９］に記載の遮光用加飾印刷インキを、タッチパネルのガラス面の外周部分に塗布し、２００〜３００℃の温度で硬化して形成する、白色加飾部を有するタッチパネルの製造方法。 Furthermore, the present invention includes the following aspects [1] to [11].
[1] A white thermosetting composition comprising the following component (A), component (B) and component (C) as essential components, and cured by a methylolation reaction between an acetoacetoxy group and a hydroxyl group.
Component (A): (A-1) A combination of a (meth) acrylic copolymer resin having an acetoacetoxy group and a (meth) acrylic copolymer resin having two or more hydroxyl groups in one molecule, and (A-2) 1 At least one selected from the group consisting of (meth) acrylic copolymer resins having an acetoacetoxy group and a hydroxyl group in the molecule Component (B): White pigment Component (C): Solvent [2] At least one of component (A) is The white thermosetting composition according to [1], comprising an acid group.
[3] The white thermosetting composition according to [2], wherein the acid group is a carboxyl group, and the acid value of the component (A) containing the acid group is 10 to 200 KOHmg / g.
[4] The component (A) is obtained by copolymerizing two or more monomers including at least one selected from 2-acetoacetoxyethyl (meth) acrylate and 2-acetoacetoxypropyl (meth) acrylate ( The white thermosetting composition according to any one of [1] to [3], comprising a (meth) acrylic copolymer resin.
[5] At least one of the components (A) is represented by the formula (1)

(In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 1 to 4 carbon atoms.)
The white thermosetting composition according to any one of [1] to [4], which is a (meth) acrylic copolymer resin having a structure derived from a monomer represented by the formula:
[6] The white heat according to any one of [1] to [5], wherein the component (A) contains a (meth) acrylic copolymer resin having a polystyrene-equivalent mass average molecular weight of 5000 to 50000. Curable composition.
[7] The white thermosetting composition according to any one of [1] to [6], wherein the component (B) is titanium oxide.
[8] The white thermosetting composition according to any one of [1] to [7], which is used to form a decorative portion of the touch panel by screen printing.
[9] A decorative printing ink for shading a touch panel comprising the white thermosetting composition according to any one of [1] to [8].
[10] An image display device having a decorative portion formed using the decorative printing ink for shading of the touch panel according to [9].
[11] Manufacture of a touch panel having a white decoration portion, which is formed by applying the decorative printing ink for shading according to [9] to the outer peripheral portion of the glass surface of the touch panel and curing at 200 to 300 ° C. Method.

  The cured film of the white thermosetting composition of the present invention is excellent in heat yellowing resistance, acid resistance, and alkali resistance. The decorative part obtained from the decorative printing ink for shading of the touch panel of the present invention is excellent in heat yellowing resistance, acid resistance, and alkali resistance. The image display device of the present invention has a decorative portion having good heat yellowing resistance, acid resistance, alkali resistance and heat resistance.

Hereinafter, the present invention will be specifically described. However, the present invention is not limited to this embodiment.
In the present specification, “(meth) acrylic monomer” refers to acrylic acid, methacrylic acid, acrylic ester, methacrylic ester and derivatives thereof. The derivative is a compound produced from any one of acrylic acid, methacrylic acid, acrylic acid ester and methacrylic acid ester as a starting material, and has an acryloyloxy group or a methacryloyloxy group. In this specification, “(meth) acrylic copolymer resin” means a resin obtained by copolymerizing at least two types of monomers selected from (meth) acrylic monomers, or (meth) acrylic monomers and (meth) ) A resin obtained by copolymerization with monomers other than acrylic monomers.

The present invention (I) contains the following component (A), component (B) and component (C) as essential components, and is cured by a methylolation reaction between an acetoacetoxy group and a hydroxyl group, and is characterized by white thermosetting It is a composition.
Component (A): A combination of a (meth) acrylic copolymer resin having an acetoacetoxy group and a (meth) acrylic copolymer resin having two or more hydroxyl groups in one molecule, and an acetoacetoxy group and a hydroxyl group in one molecule At least one selected from the group consisting of (meth) acrylic copolymer resins Component (B): White pigment Component (C): Solvent

First, the component (A) will be described. The component (A) is at least one selected from the group consisting of the following component (A-1) and component (A-2).
Component (A-1): (meth) acrylic copolymer resin having acetoacetoxy group (hereinafter referred to as “component (A-1-a)”) and (meth) acrylic having two or more hydroxyl groups in one molecule Combination of copolymer resin (hereinafter referred to as “component (A-1-b)”) Component (A-2): (meth) acrylic copolymer resin having acetoacetoxy group and hydroxyl group in one molecule

  Component (A-1) is a combination of component (A-1-a) and component (A-1-b), and the mixing ratio is (the total number of acetoacetoxy groups in component (A-1-a)). / (Total number of hydroxyl groups of component (A-1-b)) is preferably adjusted to be 0.1 to 10, more preferably 0.15 to 6.5, 0.2 More preferably, it is -5.0. When the ratio of (total number of acetoacetoxy groups of component (A-1-a)) / (total number of hydroxyl groups of component (A-1-b)) is in the range of 0.1 to 10, After the curable composition is cured by a methylolation reaction, there remains little unreacted hydroxyl group or acetoacetoxy group and does not adversely affect heat-resistant yellowing, acid resistance, alkali resistance and the like.

Next, the component (A-1-a) will be described.
The component (A-1-a) is a (meth) acrylic copolymer resin having an acetoacetoxy group and can be cured by a methylolation reaction with a component (A-1-b) described later. There is no particular limitation as long as it is an acrylic copolymer resin.

  A (meth) acrylic copolymer resin having an acetoacetoxy group is obtained by, for example, copolymerizing a (meth) acrylic monomer containing an acetoacetoxy group and a (meth) acrylic monomer having no acetoacetoxy group, no acid group, and no hydroxyl group. Or by copolymerizing two or more of (meth) acrylic monomers containing an acetoacetyl group, or by copolymerizing a (meth) acrylic monomer containing an acetoacetoxy group and a (meth) acrylic monomer having an acid group Can be prepared.

  Examples of the (meth) acrylic monomer having an acetoacetoxy group include 2-acetoacetoxyethyl (meth) acrylate and 2-acetoacetoxypropyl (meth) acrylate. Among these, 2-acetoacetoxyethyl methacrylate is particularly preferable from the viewpoint of easy availability and heat-resistant yellowing.

  The component (A-1-a) preferably has an acid group from the viewpoint of heat-resistant yellowing. The component (A-1-a) having an acid group is, for example, a comonomer having an acid group as a raw material comonomer when the component (A-1-a) is produced by copolymerization, for example, a (meth) acryl having an acid group. It can manufacture by mix | blending a monomer. It is preferable that the compounding quantity of the (meth) acryl monomer which has an acid group with respect to all the raw material components at the time of manufacturing a component (A-1-a) is 2-40 mass%. If the blending amount is within this range, sufficient heat-resistant yellowing can be expressed.

Although the said acid group is not specifically limited, Usually, a carboxyl group, a phosphoric acid group, a sulfonic acid group etc. are mentioned, A carboxyl group is especially preferable. The phosphoric acid group means — (H ₂ PO ₄ ).

  Examples of the (meth) acrylic monomer having an acid group include (meth) acrylic acid, 2- (meth) acryloyloxyethyl acid phosphate, acid phosphooxypolyoxyethylene glycol mono (meth) acrylate, and acid phosphooxypolyoxypropylene glycol Mono (meth) acrylate, 2-((meth) acryloyloxy) ethanesulfonic acid and the like can be mentioned. Among these, methacrylic acid is preferable from the viewpoint of easy availability and heat-resistant yellowing.

  The (meth) acrylic monomer having no acetoacetoxy group, no acid group or hydroxyl group is not particularly limited, but methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) ) Acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, neopentyl (meth) acrylate, benzyl (meth) acrylate , Isoamyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, lauryl (meth) acrylate, dodecyl (meth) acrylate, cyclopentyl (Meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, ethylcyclohexyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, rosin (meth) acrylate, norbornyl (meth) acrylate, 5 -Methylnorbornyl (meth) acrylate, 5-ethylnorbornyl (meth) acrylate, allyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 1,1,1-trifluoroethyl (meth) acrylate, par Fluoroethyl (meth) acrylate, perfluoro-n-propyl (meth) acrylate, perfluoro-isopropyl (meth) acrylate, triphenylmethyl (meth) acrylate, cumyl (meth) Chryrate, 3- (N, N-dimethylamino) propyl (meth) acrylate, glyceryl mono (meth) acrylate, butanetriol mono (meth) acrylate, pentanetriol monomethacrylate, dicyclopentenyl methacrylate, dicyclopentanyl (meth) ) Acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, naphthalene (meth) acrylate, anthracene (meth) acrylate, and the like. Among these, methyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and isobornyl (meth) acrylate are preferable from the viewpoint of easy availability and heat-resistant yellowing.

Next, the component (A-1-b) will be described.
Component (A-1-b) is a (meth) acrylic copolymer resin having two or more hydroxyl groups in one molecule, and is cured by the methylolation reaction with component (A-1-a) described above. (Meth) acrylic copolymer resin is not particularly limited.

  A (meth) acrylic copolymer resin having two or more hydroxyl groups in one molecule is, for example, a copolymer of a (meth) acrylic monomer having a hydroxyl group and a (meth) acrylic monomer having no acetoacetoxy group, no acid group or no hydroxyl group. By doing so, it can be prepared.

  As the (meth) acrylic monomer having a hydroxyl group, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxy (Meth) butyl acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3- (o-phenylphenoxy) propyl (meth) acrylate, 2-hydroxyethyl (meth) acrylamide and the like. Among these, 2-hydroxyethyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate are particularly preferable from the viewpoint of easy availability and reactivity.

Next, a component (A-2) is demonstrated.
Component (A-2) is a (meth) acrylic copolymer resin having an acetoacetoxy group and a hydroxyl group in one molecule, and can be cured by an intramolecular and / or intermolecular methylolation reaction (meta If it is an acrylic copolymer resin, there will be no restriction | limiting in particular.

  The (meth) acrylic copolymer resin having an acetoacetoxy group and a hydroxyl group is, for example, a (meth) acrylic monomer having an acetoacetoxy group, a (meth) acrylic monomer having a hydroxyl group, an acetoacetoxy group, neither an acid group nor a hydroxyl group. It can be prepared by copolymerizing a (meth) acrylic monomer or by copolymerizing a (meth) acrylic monomer having an acetoacetoxy group and a (meth) acrylic monomer having a hydroxyl group.

  The ratio of (total number of acetoacetoxy groups in component (A-2)) / (total number of hydroxyl groups in component (A-2)) in component (A-2) can be adjusted to 0.1 to 10. Preferably, it is 0.15-6.5, and more preferably 0.2-5.0. When the ratio of (total number of acetoacetoxy groups of component (A-2)) / (total number of hydroxyl groups of component (A-2)) is in the range of 0.1 to 10, white thermosetting composition After curing by methylolation reaction, there is little residual unreacted hydroxyl group or acetoacetoxy group, and it does not adversely affect heat-resistant yellowing, acid resistance, alkali resistance and the like.

  In order for the white thermosetting composition of the present invention (I) to exhibit sufficient heat yellowing resistance, acid resistance, and alkali resistance, the component (A) has an acid group and is represented by the formula (1). It is further preferable to contain a (meth) acrylic copolymer resin having a structure derived from the monomer to be prepared. That is, the component (A) is a copolymer obtained by copolymerizing at least two kinds of monomers, and at least one of the monomers is a monomer represented by the following formula (1). More preferably, it is a copolymer.

（式中、Ｒ^１は水素原子またはメチル基を示し、Ｒ^２は炭素数１〜４のアルキル基を示す。）

(In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 1 to 4 carbon atoms.)

  As a monomer represented by Formula (1), for example, methyl (meth) acrylate and ethyl (meth) acrylate are preferable, and methyl (meth) acrylate is particularly preferable.

  The polystyrene-converted mass average molecular weight obtained by gel permeation chromatography of the component (A) is preferably 5000 to 50000, more preferably 8000 to 45000, and still more preferably 10,000 to 40000. When the molecular weight is 5000 or more, peeling of the coating film hardly occurs during the acid resistance and alkali resistance processes. On the other hand, when the molecular weight is 50000 or less, the viscosity of the white thermosetting composition does not become too high, and coating can be performed uniformly.

  In addition, in the (meth) acrylic copolymer resin, there is an unsaturated group-containing copolymer resin in which a double bond or the like is added to the side chain. However, in the present invention, the component (A) ( It is preferable that a double bond or the like is not added to the (meth) acrylic copolymer resin.

  The copolymerization reaction for preparing the component (A) (meth) acrylic copolymer resin can be carried out according to a radical polymerization method known in the art. For example, after each monomer for synthesizing a copolymer is dissolved in a solvent, a polymerization initiator is added to the solution and reacted at 50 to 130 ° C. for 1 to 20 hours.

  The polymerization initiator that can be used for this copolymerization reaction is not particularly limited, and examples thereof include azobisisobutyronitrile, azobisisovaleronitrile, dimethyl 2,2′-azobis (2-methylpropyl). Pionate), benzoyl peroxide, t-butylperoxy-2-ethylhexanoate and the like. These can be used alone or in combination of two or more. The amount of the polymerization initiator used is generally 0.5 to 20 parts by mass, preferably 1 to 10 parts by mass when the total amount of monomers charged is 100 parts by mass.

  When the (meth) acrylic copolymer resin obtained as described above has an acid group, its acid value (JIS K6901 5.3) is not limited as long as the desired effect of the present invention is exhibited, but preferably It is 10-200 mgKOH / g, More preferably, it is 20-100 mgKOH / g. When the acid value is 10 KOHmg / g or more, the heat-resistant yellowing of the (meth) acrylic copolymer resin is sufficiently exhibited. On the other hand, when the acid value is 200 mgKOH / g or less, the solubility in a solvent increases when producing a (meth) acrylic copolymer resin having a polystyrene-equivalent mass average molecular weight of 5000 to 50000, and the production is easy. Become.

  The content of the component (A) contained in the white thermosetting composition of the present invention is 20 based on the total amount of the remaining components (solid content, etc.) obtained by removing the solvent (C) from the white thermosetting composition. It is preferable that it is -70 mass%. If the content of the component (A) is 20% by mass or more, acid resistance and alkali resistance are sufficient, and if it is 70% by mass or less, a sufficient ratio is achieved by the ratio of the white pigment (B). it can.

  Next, the white pigment (B) will be described. The white pigment (B) is not particularly limited, and examples thereof include titanium oxide, barium sulfate, zinc oxide, zirconium oxide, aluminum oxide, calcium carbonate, magnesium carbonate, silica, polymethylsilsesquioxane, talc, and mica. . Among these, titanium oxide is preferable in order to improve concealability. Titanium oxide is industrially classified into a rutile type and an anatase type, but a rutile type titanium oxide is more preferable for the purpose of improving heat-resistant yellowing.

  The content of the white pigment (B) in the white thermosetting composition of the present invention is 30 to 30 based on the total amount of the remaining components (solid content, etc.) obtained by removing the solvent (C) from the white thermosetting composition. It is preferable that it is 80 mass%. If the content of the white pigment (B) is 30% by mass or more, a predetermined color cannot be expressed, and if it is 80% by mass or less, acid resistance and alkali resistance are not deteriorated.

  Next, the solvent (C) will be described. The solvent (C) is not particularly limited. Although a solvent (C) can be used also for a white thermosetting composition, it can be used also at the time of manufacture of the (meth) acrylic copolymer resin contained in a component (A). In this case, there is no particular limitation as long as it is an inert solvent that does not react with the (meth) acrylic copolymer resin having a polystyrene-reduced mass average molecular weight of 5000 to 50000.

As the solvent (C), the same solvent as used in the production of the (meth) acrylic copolymer resin contained in the component (A) (copolymerization reaction) can be used, and is included after the copolymerization reaction. The solvent used can be used as it is, or can be further added. Further, when other components are added, they may coexist there. Specific examples of the solvent (C) include propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol ethyl ether acetate. , Diethylene glycol diethyl ether, diethylene glycol monobutyl ether, γ-butyrolactone, ethyl lactate, 2,2,4-trimethylpentane-1,3-diol monoisobutyrate and the like. These can be used alone or in combination of two or more. Among these, high boiling points such as γ-butyrolactone, dipropylene glycol monomethyl ether acetate, tripropylene glycol monomethyl ether, diethylene glycol ethyl ether acetate, 2,2,4-trimethylpentane-1,3-diol monoisobutyrate Solvents are preferred.
The content of the solvent (C) in the white thermosetting composition of the present invention is preferably 30 to 80% by mass, more preferably 35 to 70% by mass, based on the entire white thermosetting composition. More preferably, it is 40-60 mass%. If it is content of this range, it will become a white curable composition which has a suitable viscosity.

  In addition to the above components, the white thermosetting composition of the present invention includes known antioxidants, coupling agents, leveling agents, antifoaming agents, thermal polymerization inhibitors and the like in order to impart predetermined characteristics. You may mix | blend a well-known additive. The amount of these additives is not particularly limited as long as it does not impair the effects of the present invention.

  The white thermosetting composition of the present invention preferably has a curing temperature of 150 ° C. or higher. If the curing temperature is 150 ° C. or higher, the acid resistance and alkali resistance will not deteriorate.

  The white thermosetting composition of the present invention can be produced by kneading the above components using a known kneading apparatus. Examples of the kneader include a roll mill, a bead mill, and a planetary mixer.

  The white thermosetting composition of this invention is suitable as a thermosetting composition used for the decoration part of the touchscreen integrated in a smart phone, tablet PC, etc. Moreover, since the white thermosetting composition of this invention gives the cured film excellent in heat-resistant yellowing, acid resistance, alkali resistance, etc., it can also be used for various coatings, adhesives, binders for printing inks, and the like.

  The method for applying to the glass surface or the like when obtaining a cured film of the white thermosetting composition is not particularly limited, but it may be performed on a glass substrate using a screen printing method, a roll coating method, a curtain coating method, a spray coating method, or the like. Can be painted on. Among these, screen printing is preferable. Moreover, after application | coating of a white thermosetting composition, it is preferable to volatilize a solvent (E) by heating using heating means, such as a circulation type oven, an infrared heater, a hotplate, as needed. The heating conditions are not particularly limited, and may be set as appropriate according to the type of white thermosetting composition to be used. In general, it may be heated at a temperature of 50 to 120 ° C. for 10 to 60 minutes.

  Next, the formed coating film is cured. Similarly to the above, white thermosetting is achieved by heating at a temperature of 150 to 300 ° C., preferably at a temperature of 200 to 300 ° C. for 30 to 90 minutes using a heating means such as a circulation oven, an infrared heater or a hot plate. The composition is cured. The white thermosetting composition of the present invention preferably does not use a curing catalyst in order to improve heat-resistant yellowing.

  The decorative part thus manufactured is manufactured using a white thermosetting composition that gives a white pattern excellent in heat-resistant yellowing, acid resistance, and alkali resistance. It has a white pattern with little change.

  The present invention (II) is a decorative printing ink for shading of a touch panel comprising the white thermosetting composition of the present invention (I). The white thermosetting composition of the present invention (I) can be used as it is as a decorative printing ink for shading of a touch panel.

  This invention (III) is an image display apparatus which has a decoration part formed using the decorative printing ink for light shielding of the touchscreen of this invention (II). An image display device can be manufactured according to a conventional method, for example, using glass for a touch panel in which a decorative portion is formed.

  The present invention (IV) is a white decoration formed by applying the shading decorative printing ink of the touch panel of the present invention (II) to the outer peripheral portion of the glass surface of the touch panel and curing it at a temperature of 200 to 300 ° C. It is a manufacturing method of the touch panel which has a part. For example, the white decorative portion is applied to the outer peripheral portion of the glass surface of the touch panel with the decorative printing ink for shading of the touch panel of the present invention (II), dried as necessary, and then at a temperature of 150 to 300 ° C. The film can be formed by heating and curing at a temperature of preferably 200 to 300 ° C.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail with reference to an Example, this invention is not limited to these Examples. In this example, parts and percentages are all based on mass unless otherwise specified. Moreover, the measuring method of an acid value and a mass average molecular weight is as follows.

[Acetoacetoxy group value]
The acetoacetoxy group value in the present invention is a theoretical calculated value obtained from the following formula.
(Wa / Mw) × 56100 / Ws
Wa: Charged weight of 2-acetoacetoxyethyl acrylate (g)
Mw: Molecular weight of 2-acetoacetoxyethyl acrylate (214 g / mol)
Ws: Total charged weight of solid content (g)

[Acid value]
The acid value of the curable resin measured according to 5.3 of JIS K6901, and means the number of mg of potassium hydroxide required to neutralize the acidic component contained in 1 g of the curable resin.

[Hydroxyl value]
The hydroxyl value of the curable resin measured in accordance with JIS K6901 5.4 means the number of mg of potassium hydroxide required to neutralize acetic acid generated when acetylating 1 g of the curable resin. .

[Mass average molecular weight (Mw)]
It means a standard polystyrene equivalent mass average molecular weight measured under the following conditions using gel permeation chromatography (GPC).
Column: Shodex (trademark) LF-804 + LF-804 (manufactured by Showa Denko KK)
Column temperature: 40 ° C
Sample: 0.2% tetrahydrofuran solution of copolymer Development solvent: Tetrahydrofuran Detector: Differential refractometer (Showex (trademark) RI-71S) (manufactured by Showa Denko KK)
Flow rate: 1 mL / min

[Synthesis of Component (A)]
Production Example 1
Add 366.7 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate to a flask equipped with a stirrer, dropping funnel, condenser, thermometer and gas introduction tube, and stir while replacing with nitrogen. The temperature was raised to 95 ° C.
Next, 263.6 g of methyl methacrylate, 5.6 g of 2-acetoacetoxyethyl methacrylate, 22.1 g of methacrylic acid and 8.7 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator) were added. What was added was dropped into the flask from a dropping funnel. After completion of the dropwise addition, the mixture was stirred at 95 ° C. for 3 hours to carry out a copolymerization reaction. Next, 333.3 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate was added to the reaction solution. (Meth) acrylic copolymer resin having a solid content concentration of 30% by mass and a polystyrene-reduced weight average molecular weight of 32,000 (meth) acrylic copolymer resin (solid content acetoacetoxy group value 5 mgKOH / g, solid content acid value 48 mgKOH / g) )

Production Example 2
Add 366.7 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate to a flask equipped with a stirrer, dropping funnel, condenser, thermometer and gas introduction tube, and stir while replacing with nitrogen. The temperature was raised to 95 ° C.
Next, 237.1 g of methyl methacrylate, 5.6 g of 2-acetoacetoxyethyl methacrylate, 48.6 g of 2-methacryloyloxyethyl acid phosphate and 8.7 g of t-butylperoxy-2-ethylhexanoate What added (polymerization initiator) was dripped in the said flask from the dropping funnel. After completion of the dropwise addition, the mixture was stirred at 95 ° C. for 3 hours to carry out a copolymerization reaction. Next, 333.3 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate was added to the reaction solution. (Meth) acrylic copolymer resin having a solid content concentration of 30% by mass and a polystyrene-reduced weight average molecular weight of 28000 (meth) acrylic copolymer resin (solid content acetoacetoxy group value 5 mgKOH / g, solid content acid value 87 mgKOH / g) was obtained.

Production Example 3
Add 366.7 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate to a flask equipped with a stirrer, dropping funnel, condenser, thermometer and gas introduction tube, and stir while replacing with nitrogen. The temperature was raised to 95 ° C.
Next, 240.2 g of methyl methacrylate, 5.6 g of 2-acetoacetoxyethyl methacrylate, 45.5 g of 2- (methacryloyloxy) ethanesulfonic acid and 8.7 g of t-butylperoxy-2-ethylhexano What added the acid (polymerization initiator) was dropped into the flask from the dropping funnel. After completion of the dropwise addition, the mixture was stirred at 95 ° C. for 3 hours to carry out a copolymerization reaction. Next, 333.3 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate was added to the reaction solution. (Meth) acrylic copolymer resin having a solid content concentration of 30% by mass and an acetoacetoxy group and a sulfonic acid group having a polystyrene-reduced mass average molecular weight of 30000 (solid content acetoacetoxy group value 5 mgKOH / g, solid content acid value 44 mgKOH / g) was obtained.

Production Example 4
Add 366.7 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate to a flask equipped with a stirrer, dropping funnel, condenser, thermometer and gas introduction tube, and stir while replacing with nitrogen. The temperature was raised to 95 ° C.
Next, a mixture of 285.5 g of methyl methacrylate, 5.8 g of 2-acetoacetoxyethyl methacrylate and 8.7 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator) was added from the dropping funnel. Dropped into the flask. After completion of the dropwise addition, the mixture was stirred at 95 ° C. for 3 hours to carry out a copolymerization reaction. Next, 333.3 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate was added to the reaction solution. A (meth) acrylic copolymer resin (solid content acetoacetoxy group value 5 mgKOH / g) having an acetoacetoxy group having a solid content concentration of 30% by mass and a polystyrene-reduced mass average molecular weight of 28000 was obtained.

Production Example 5
427.8 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate was added to a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer and a gas introduction tube, and stirred while purging with nitrogen. The temperature was raised to 95 ° C.
Next, 262.3 g of methyl methacrylate, 72.3 g of 2-hydroxyethyl methacrylate and 15.4 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator) were added from the dropping funnel. It was dripped in the flask. After completion of the dropwise addition, the mixture was stirred at 95 ° C. for 3 hours to carry out a copolymerization reaction. Next, 222.2 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate was added to the reaction solution. Thus, a (meth) acrylic copolymer resin (solid content hydroxyl value 89 mgKOH / g) having a hydroxyl content with a solid content concentration of 35% by mass and a polystyrene-reduced mass average molecular weight of 21,000 was obtained.

Production Example 6
Add 366.7 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate to a flask equipped with a stirrer, dropping funnel, condenser, thermometer and gas introduction tube, and stir while replacing with nitrogen. The temperature was raised to 95 ° C.
Next, 250.1 g of methyl methacrylate, 30.0 g of methacrylic acid, 11.2 g of 2-hydroxyethyl methacrylate and 8.7 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator) were added. This was dropped into the flask from a dropping funnel. After completion of the dropwise addition, the mixture was stirred at 95 ° C. for 3 hours to carry out a copolymerization reaction. Next, 333.3 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate was added to the reaction solution. A (meth) acrylic copolymer resin (solid content acid value 65 mgKOH / g, solid content hydroxyl value 16 mgKOH / g) having a carboxyl group and a hydroxyl group having a solid content concentration of 30% by mass and a polystyrene-equivalent weight average molecular weight of 33000 was obtained. .

Production Example 7
Add 366.7 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate to a flask equipped with a stirrer, dropping funnel, condenser, thermometer and gas introduction tube, and stir while replacing with nitrogen. The temperature was raised to 95 ° C.
Next, 245.5 g methyl methacrylate, 5.6 g 2-acetoacetoxyethyl methacrylate, 29.2 g methacrylic acid and 11.0 g 2-hydroxyethyl methacrylate, 8.7 g t-butylperoxy-2- What added ethyl hexanoate (polymerization initiator) was dripped in the said flask from the dropping funnel. After completion of the dropwise addition, the mixture was stirred at 95 ° C. for 3 hours to carry out a copolymerization reaction. Next, 333.3 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate was added to the reaction solution. A (meth) acrylic copolymer resin having a solid content concentration of 30% by mass and a polystyrene-reduced mass average molecular weight of 32,000 in terms of polystyrene (solid content acetoacetoxy group value 5 mgKOH / g, solid content acid value 64 mgKOH) / G, solid content hydroxyl value 16 mgKOH / g).

Comparative production example 1
Add 510.8 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate to a flask equipped with a stirrer, dropping funnel, condenser, thermometer and gas introduction tube, and stir while replacing with nitrogen. The temperature was raised to 95 ° C.
Next, 286.8 g of methyl methacrylate and 13.2 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator) were added dropwise from the dropping funnel into the flask. After completion of the dropwise addition, the polymerization reaction was carried out by stirring at 95 ° C. for 3 hours. Next, 189.2 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate was added to the reaction solution, A methacrylic polymer resin having a solid content concentration of 30% by mass and a polystyrene-equivalent weight average molecular weight of 20,500 was obtained.

Comparative production example 2
Add 510.8 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate to a flask equipped with a stirrer, dropping funnel, condenser, thermometer and gas introduction tube, and stir while replacing with nitrogen. The temperature was raised to 95 ° C.
Next, 242.6 g of methyl methacrylate, 44.3 g of methacrylic acid and 13.2 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator) were added into the flask from the dropping funnel. It was dripped. After completion of the dropwise addition, a copolymerization reaction was performed by stirring at 95 ° C. for 3 hours, and then 189.2 g of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate was added to the reaction solution. Then, a (meth) acrylic copolymer resin (solid content acid value 96 mgKOH / g) having an acid group with a solid content concentration of 30% by mass and a polystyrene-equivalent weight average molecular weight of 22,000 was obtained.

Comparative production example 3
In a reaction apparatus in which a stirrer, a thermometer, an air-sealed tube, and a reflux condenser are set in a four-necked flask, 175.0 g of bisphenol A type epoxy resin [“jER825” manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 175], 72 0.0 g of acrylic acid, 164.7 g of diethylene glycol ethyl ether acetate, 0.7 g of triphenylphosphine and 0.3 g of methylhydroquinone were charged, heated to 120 ° C. while blowing air, and reacted for about 20 hours. A reaction product having a value of 0.5 KOH mg / g was obtained.
Next, 85.1 g of tetrahydrophthalic anhydride was charged and reacted at 100 ° C. for 6 hours until the absorption peak of acid anhydride disappeared by infrared absorption analysis, and then 452.1 g of diethylene glycol ethyl ether acetate was charged. A resin solution having a weight average molecular weight of 7000 in terms of polystyrene having a partial acid value of 95 KOH mg / g and a solid content concentration of 35% was obtained.

  Table 1 summarizes the production examples and comparative production examples.

[Preparation of white thermosetting composition]
Using the compounds produced in the production examples and comparative production examples, a white thermosetting composition was prepared by blending the composition according to the blending composition shown in Table 2 and kneading with a three-roll mill.

* 1 White pigment: Rutile titanium oxide “SR-1” manufactured by Sakai Chemical Industry Co., Ltd.
* 2 Additional solvent: 2,2,4-trimethylpentane-1,3-diol monoisobutyrate (Examples 1 to 7 and Comparative Examples 1 to 6) and diethylene glycol ethyl ether acetate (Comparative Example 7)

[Preparation and evaluation of coating film]
A glass plate (10 mm × 10 mm × 0.7 mm, glass type, trade name: EAGLE XG (trademark)) using a polyester screen on which a 100-mesh pattern is drawn by screen printing. The coated film was dried with a hot air drier at 100 ° C. for 20 minutes.
Thereafter, it was cured for 30 minutes with a hot air dryer at 200 ° C. and for 30 minutes with a hot air dryer at 240 ° C. to obtain a coating film having a thickness of 20 μm.

(Heat-resistant yellowing evaluation)
About each coating film, the initial value of b * of L * a * b * color system was measured using Konica Minolta color difference meter CM-5. Thereafter, the coating film was placed in a hot air dryer at 250 ° C. for 27 hours, and b * was measured again. The heat yellowing resistance was evaluated according to the following criteria from the difference between b * and b * before and after (Δb).
○: b * after heating at 250 ° C. is less than 0.5 and Δb is less than 0.5 Δ: b * after heating at 250 ° C. is less than 1.0 and Δb is less than 1.0 ×: b after heating at 250 ° C. * Is 1.0 or more or Δb is 1.0 or more

(Acid resistance evaluation)
Each coating film was immersed in 30% hydrochloric acid at 50 ° C. for 10 minutes, the coating film after immersion was visually observed, and acid resistance was evaluated according to the following criteria.
○: No peeling (peeling) or dissolution of the coating film ×: No peeling or peeling of the coating film

(Alkali resistance evaluation)
Each coating film was immersed in a 5% aqueous sodium hydroxide solution at 50 ° C. for 10 minutes, the coating film after immersion was visually observed, and acid resistance was evaluated according to the following criteria.
○: No peeling (peeling) or dissolution of the coating film ×: No peeling or peeling of the coating film

  The white thermosetting composition of this invention can be utilized suitably as a thermosetting composition used for the decoration part of the touchscreen integrated in a smart phone, tablet PC, etc. In addition, the white thermosetting composition of the present invention provides a cured film excellent in heat yellowing resistance, acid resistance, alkali resistance, etc., and therefore can be used for various coatings, adhesives, printing ink binders, and the like. .

Claims (11)

A white thermosetting composition comprising the following component (A), component (B) and component (C) as essential components, and cured by a methylolation reaction of an acetoacetoxy group and a hydroxyl group.
Component (A): (A-1) A combination of a (meth) acrylic copolymer resin having an acetoacetoxy group and a (meth) acrylic copolymer resin having two or more hydroxyl groups in one molecule, and (A-2) 1 At least one selected from the group consisting of (meth) acrylic copolymer resins having an acetoacetoxy group and a hydroxyl group in the molecule Component (B): White pigment Component (C): Solvent   The white thermosetting composition according to claim 1, wherein at least one of the components (A) contains an acid group.   The white thermosetting composition according to claim 2, wherein the acid group is a carboxyl group, and the acid value of the component (A) containing the acid group is 10 to 200 mgKOH / g.   (Meth) acrylic obtained by copolymerizing two or more monomers including at least one component (A) selected from 2-acetoacetoxyethyl (meth) acrylate and 2-acetoacetoxypropyl (meth) acrylate The white thermosetting composition according to claim 1, comprising a copolymer resin. At least one of the components (A) is represented by the formula (1)

(In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 1 to 4 carbon atoms.)
The white thermosetting composition according to claim 1, wherein the white thermosetting composition is a (meth) acrylic copolymer resin having a structure derived from a monomer represented by the formula:   The white thermosetting composition according to any one of claims 1 to 5, wherein the component (A) contains a (meth) acrylic copolymer resin having a polystyrene-equivalent mass average molecular weight of 5000 to 50000. object.   A component (B) is a titanium oxide, The white thermosetting composition of any one of Claims 1-6 characterized by the above-mentioned.   The white thermosetting composition of any one of Claims 1-7 used in order to form the decorating part of a touchscreen by screen printing.   A decorative printing ink for shading of a touch panel, comprising the white thermosetting composition according to claim 1.   The image display apparatus which has a decoration part formed using the decorating printing ink for light shielding of the touchscreen of Claim 9.   The manufacturing method of the touch panel which has a white decoration part which apply | coats the decorative printing ink for shading of the touchscreen of Claim 9 to the outer peripheral part of the glass surface of a touchscreen, and hardens | cures at the temperature of 200-300 degreeC. .