JP2014088567A - Photocurable ink for ink-jet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink for ink-jet which can form a cover lay or a solder resist with reduced warpage and heat resistance, and in superior balance of such as flexibility.SOLUTION: An ink for ink-jet containing epoxy resin (A) of a dicyclopentadiene type contains a compound (B) having a phenolic hydroxyl group and/or a carboxyl group, a diluent (C) and a photoinitiator (D) in addition if necessary. A curing membrane with reduced warpage and high heat resistance is formed by the ink for ink-jet.

Description

  The present invention is printed using an ink jet printing method and then cured in an exposure and baking process, and is used for display elements for liquid crystals, EL, etc., and electronic circuit boards such as printed wiring boards, flexible wiring boards, and semiconductor package boards. More particularly, the present invention relates to an ink-jet ink suitable for a coverlay for protecting a metal wiring surface forming a predetermined circuit pattern, a solder resist, or the like.

  In recent years, electronic devices have been miniaturized, and electronic circuit boards using lightweight and flexible printed wiring boards are often used. Such an electronic circuit board is formed by, for example, etching a metal layer such as copper to form a wiring portion having a predetermined circuit pattern and coating a cover lay which is a protective film for protecting the metal wiring. It is manufactured by. The current main coating process includes a method in which a cover lay film is bonded to a wiring board by a hot press, and a method in which a cover lay ink is cured by light and heat using a screen printing method or a photolithography method. . In this coating process, there is a problem that when the adhesive component of the film or the ink itself is cured by light or heat, curing shrinkage occurs and the coverlay warps. In particular, with the miniaturization of electronic devices, flexible wiring boards are becoming thinner, and there is a need for a coverlay that does not warp even when coated on thin flexible wiring boards. The demand for sex is also increasing.

  However, suppressing the warpage of the coverlay and increasing the heat resistance are contradictory, and the warpage can be suppressed even with a thin flexible substrate, and increasing the glass transition temperature, which is an indicator of the heat resistance of the cured film. Extremely difficult.

On the other hand, in terms of heat resistance, coverlays using polyimide as a material are commercially available, but they are still expensive, and the applications used in terms of cost are limited.

  Currently, the coverlay film currently used has a low yield in the process of attaching to an electronic circuit board. Compared to photolithography, pattern formation by inkjet method is simpler and can be expected to reduce the amount of material used. Therefore, it is recommended to use it for manufacturing printed wiring boards used in electronic equipment. (For example, refer to JP2003-302642A (Patent Document 1) and JP2005-68280A (Patent Document 2)).

  However, inkjet inks are difficult to eject unless they have a low viscosity, and it is difficult to provide the necessary properties for the coverlay compared to screen printing and photolithography methods that allow printing even at high viscosity.

  Up to now, dicyclopentadiene type epoxy resin-containing ink, silica (Japanese Patent Laid-Open No. 2000-169677), inorganic filler (Japanese Patent Laid-Open No. 2001-226461) and filler (Japanese Patent Laid-Open No. 2004-262080) have been added to warp Reduced epoxy resin compositions have been developed. However, the epoxy resin composition to which these solids are added is unsuitable for inkjet ejection, and inkjet ejection is impossible from the viewpoint of viscosity. Moreover, since it does not have photocurability, versatility is narrow.

  In such circumstances, a protective film that can be cured only by light, has low warpage, has a high glass transition temperature, and has heat resistance is desired, and further, a low-viscosity ink that can be ejected as an inkjet ink is desired.

JP 2003-302642 A JP 2005-68280 A Japanese Patent Application Laid-Open No. 2000-169677 JP 2001-226461 A JP 2004-262080 A

  Under the above circumstances, an object of the present invention is to provide an ink-jet ink that is capable of forming a cover lay or a solder resist that has reduced warpage, has heat resistance, and has a good balance such as bending resistance. .

The inventors of the present invention provide an epoxy resin (A) having a specific structure, a compound (B) having a phenolic hydroxyl group and / or a carboxyl group, a diluent (C), and a photopolymerization initiator (D). It was found that the ink-jet ink contained can form a cured film with particularly low warpage and high heat resistance, and the present invention has been completed based on this finding. Furthermore, the present invention provides such an inkjet ink, a cured film obtained from the inkjet ink, a method for forming the cured film, and the like.
The present invention includes the following items.

[1] A photocurable inkjet ink containing a dicyclopentadiene type epoxy resin (A), the central portion of the photocurable inkjet ink on a 4 cm square polyimide film (thickness: 12.5 μm) The four-end warp height of a polyimide film having a cured film (thickness 10 μm) obtained by forming a 3 cm square coating film by ink-jet coating and curing the coating film with light or heat The photocurable inkjet ink whose average value is 3 mm or less, and the glass transition temperature of the cured film obtained from this photocurable inkjet ink is 90 degreeC or more.

[2] The dicyclopentadiene type epoxy resin (A) is an epoxy resin having a dicyclopentadiene skeleton having at least one glycidyl ether bond and at least one dicyclopentadienyl group in one molecule. The photocurable inkjet ink according to [1].

（式中、Ｒ^１、Ｒ^２およびＲ^３は独立して、炭素数１〜１０の有機基であり、Ｒ^４、Ｒ^５およびＲ^６は独立して、水素、炭素数１〜１２のアルキル、またはハロゲンであり、ｎは０以上１０までの整数である） [3] The photocurable inkjet ink according to [1] or [2], wherein the dicyclopentadiene type epoxy resin (A) is represented by the following formula (1).

Wherein R ¹ , R ² and R ³ are each independently an organic group having 1 to 10 carbon atoms, and R ⁴ , R ⁵ and R ⁶ are independently hydrogen, alkyl having 1 to 12 carbon atoms. , Or halogen, and n is an integer of 0 or more and 10)

（式中、ｎは０以上１０までの整数である） [4] The photocurable inkjet ink according to any one of [1] to [3], wherein the dicyclopentadiene type epoxy resin (A) is represented by the following formula (2).

(Where n is an integer from 0 to 10)

[5] The photocurable inkjet ink according to any one of [1] to [4], further including a compound (B) having a phenolic hydroxyl group and / or a carboxyl group.

[6] The photocuring according to [5], wherein the compound (B) is any one of a compound having a radical polymerizable double bond, or an oligomer or a polymer obtained from a compound having a radical polymerizable double bond. Inkjet ink.

[7] The compound (B) is at least one of polyvinylphenol, hydroxyphenyl (meth) acrylate, monohydroxyethyl phthalate (meth) acrylate, and monohydroxyethyl tetrahydrophthalate (meth) acrylate. [5] Or the photocurable inkjet ink as described in [6].

[8] The photocurable inkjet ink according to any one of [1] to [7], further including a diluent (C).

[9] The photocurable inkjet ink according to [8], wherein the diluent (C) has a viscosity at 25 ° C. of 0.1 to 100 mPa · s.

[10] The photocurable inkjet ink according to [8] or [9], wherein the diluent (C) is monofunctional (meth) acrylate or polyfunctional (meth) acrylate.

[11] The photocurable inkjet ink according to any one of [1] to [10], further including a photopolymerization initiator (D).

[12] The photocurable inkjet ink according to [11], wherein the photopolymerization initiator (D) is at least one compound selected from the group consisting of acylphosphine oxides and alkylphenone compounds.

[13] The dicyclopentadiene type epoxy resin (A) is an epoxy resin represented by the formula (1), and the compound (B) is composed of polyvinylphenol, hydroxyphenyl (meth) acrylate, and monohydroxyethyl methacrylate phthalate. The diluent (C) is at least one selected from the group consisting of tetrahydrofurfuryl methacrylate and dipropylene glycol diacrylate, and the photopolymerization initiator (D) is 2, The photocurable inkjet ink according to any one of [1] to [12], which is 4,6-trimethylbenzoyldiphenylphosphine oxide and contains phenothiazine as a polymerization inhibitor.

[14] The photocurable inkjet ink according to any one of [1] to [13], wherein a viscosity at 25 ° C. is 1 to 200 mPa · s.

[15] The photocurable inkjet ink according to any one of [1] to [14], wherein the viscosity at 25 ° C. is 1 to 30 mPa · s.

[16] A cured film forming method in which the photocurable inkjet ink according to any one of [1] to [15] is applied and cured by irradiating the coating film with light.

[17] A cured film forming method, wherein the cured film according to [16] is cured by further heating.

[18] A cured film obtained from the photocurable inkjet ink according to any one of [1] to [15].

[19] The cured film according to [18], which is formed in a pattern.

[20] An electronic circuit board in which the cured film described in [18] or [19] is formed on a substrate.

[21] An electronic component having the electronic circuit board according to [20].

According to the ink-jet ink according to a preferred embodiment of the present invention, an ink-jet ink having excellent reduction in film warpage, heat resistance, film curability, and flexibility, and excellent jetting characteristics in an ink-jet printing method. Can be provided.

1. Ink-jet ink of the present invention The photo-curable ink-jet ink of the present invention (hereinafter sometimes simply referred to as ink) may contain a dicyclopentadiene type epoxy resin (A). It may contain a compound (B), a diluent (C), and a photopolymerization initiator (D) characterized by having a functional hydroxyl group and / or a carboxyl group. The ink of the present invention may be colorless or colored.

  In addition, the weight average molecular weight in this specification is a value in terms of polystyrene determined by the GPC method (column temperature: 35 ° C., flow rate: 1 ml / min) using a THF column manufactured by POLYMER Laboratories as a column. In addition, the weight average molecular weight of the commercial item in this specification is a catalog publication value.

1.1 Dicyclopentadiene type epoxy resin (A)
In the present invention, the dicyclopentadiene type epoxy resin (A) is not particularly limited as long as it is an epoxy resin having a dicyclopentadiene skeleton. More preferably, it is an epoxy resin having a dicyclopentadiene skeleton having at least one glycidyl ether bond and at least one dicyclopentadienyl group in one molecule, and more preferably 1) A compound represented by the formula, particularly preferably a compound represented by the formula (2).

In the above formula (1), the organic group is, for example, alkyl, alkylene having a cyclic structure, cycloalkylene, alkenylene, or arylene. More preferred organic groups are alkyl, alkylene having a cyclic structure, or cycloalkylene. In the above formula (1), R ⁴ , R ⁵ and R ⁶ are independently hydrogen, alkyl having 1 to 12 carbons, or halogen, preferably hydrogen or methyl. R ⁴ , R ⁵ and R ⁶ may be the same or different. The same applies to R ¹ , R ² and R ³ .

  In the above formulas (1) and (2), n is an integer from 0 to 10. Preferred n is an integer of 0 to 5, and more preferred n is an integer of 0 to 2.

  The dicyclopentadiene type epoxy resin represented by the formula (2) is also commercially available from DIC Corporation as EPICLON HP-7200 series.

  The dicyclopentadiene type epoxy resin (A) used in the present invention may be a single compound or a mixture of these two or more compounds.

  When the content of the dicyclopentadiene-type epoxy resin (A) is 1 to 30% by weight of the ink solid content, the balance between low warpage and heat resistance and photocurability is improved, and viscosity capable of being ejected by inkjet. Therefore, it is preferable, more preferably 3 to 20% by weight, still more preferably 5 to 15% by weight.

1.2 Compound (B)
In the present invention, the compound (B) having a phenolic hydroxyl group and / or a carboxyl group is a compound having a phenolic hydroxyl group, a compound having a carboxyl group, or a phenolic hydroxyl group and a carboxyl group in one molecule. If it is a compound that reacts with an epoxy resin and cures, it is not particularly limited, but if it is a liquid compound, it is preferably low viscosity, and if it is a solid compound, it is highly soluble in other components It is preferable to use a compound.

1.2 (1) Compounds having phenolic hydroxyl groups Specific examples of compounds having phenolic hydroxyl groups include compounds having two or more phenolic hydroxyl groups, or phenolic hydroxyl groups and radicals from the viewpoint of moisture resistance and reliability. Although it is not particularly limited as long as it is a compound having a polymerizable double bond, dihydroxybenzenes, trihydroxybenzenes, biphenols, bisphenols, dihydroxynaphthalenes, phenol resins, phenol novolac resins, cresol novolac resins, naphthol aralkyl resins, Examples thereof include triphenolmethane resin, dicyclopentadiene-modified phenol resin, hydroxyphenyl (meth) acrylate, hydroxystyrene, vinyl ketone phenol and the like.

Among them, in particular, any one of a compound having a radical polymerizable double bond, or an oligomer and a polymer obtained from a compound having a radical polymerizable double bond has a balance between low warpage and high glass transition temperature. Further, when polyvinylphenol or hydroxyphenyl methacrylate is used, a cured film having an excellent balance between low warpage and high glass transition temperature can be produced.

  In addition, the compound having a phenolic hydroxyl group may be a single compound selected from the compounds described above or a mixture of two or more compounds.

  The compounding ratio of the compound having a phenolic hydroxyl group in the inkjet ink is, in the case of two or more phenolic hydroxyl groups, the hydroxyl group of the compound having a phenolic hydroxyl group with respect to the epoxy equivalent of the dicyclopentadiene type epoxy resin (A). It is preferable that the proportion of the equivalent amount is 0.5 to 2.0. More preferably, when the blending is 0.8 to 1.2, the curability, the heat resistance of the cured product, the electrical characteristics, etc. are improved. On the other hand, in the case of a compound having a phenolic hydroxyl group and a radical polymerizable double bond, the ratio of the hydroxyl group equivalent of the compound having a phenolic hydroxyl group to the epoxy equivalent of the dicyclopentadiene type epoxy resin (A) is 0.5. The blending is preferably less than 10 or more. More preferably, if the blending is 0.8 or more and less than 2, the curability, the heat resistance of the cured product, the electrical characteristics, etc. will be better.

1.2 (2) Compound having a carboxyl group Specific examples of a compound having a carboxyl group include compounds having two or more carboxyl groups or a carboxyl group and a radical polymerizable double bond from the viewpoint of curability. Although it does not specifically limit, As a monomer which has a carboxyl group, (meth) acrylic acid, (meth) acrylic acid dimer, crotonic acid, alpha-chloroacrylic acid, cinnamic acid, maleic acid, fumaric acid, itaconic acid, citracone Acid, mesaconic acid, β-carboxyethyl (meth) acrylate, ω-carboxypolycaprolactone mono (meth) acrylate, succinic acid mono [2- (meth) acryloyloxyethyl], maleic acid mono [2- (meth) acrylic Leuoxyethyl], phthalic anhydride and hydroxyethyl (meth) acrylate Reaction product of (e.g., phthalic acid mono-hydroxyethyl methacrylate), or a reaction product of hexahydrophthalic anhydride with hydroxyethyl (meth) acrylate. Other examples include acid-modified epoxy (meth) acrylate.

  Among them, in particular, monohydroxyethyl phthalate (meth) acrylate and monohydroxyethyl tetrahydrophthalate (meth) acrylate, the ink of the present invention has low viscosity, excellent photocurability, warpage and high glass transition temperature. A cured film having excellent properties can be produced.

  In addition, the compound having a carboxyl group may be a single compound selected from the above-described compounds or a mixture of two or more compounds.

  The proportion of the compound having a carboxyl group in the inkjet ink is such that the ratio of the carboxyl group equivalent of the compound having a carboxyl group to the epoxy equivalent of the dicyclopentadiene type epoxy resin (A) is 0.5 or more and 10 It is preferable that the formulation is less than More preferably, if the blending is 0.8 or more and less than 2, the curability, the heat resistance of the cured product, the electrical characteristics, etc. will be better.

  The compound (B) may be a mixture of the above-described compound having a phenolic hydroxyl group and the above-described compound having a carboxyl group.

1.2 (3) Compound having phenolic hydroxyl group and carboxyl group Specific examples of the compound having phenolic hydroxyl group and carboxyl group include one or more phenolic hydroxyl groups and one or more carboxyl groups from the viewpoint of curability. Is not particularly limited as long as it has one or more phenolic hydroxyl groups, one or more carboxyl groups, and one or more radical polymerizable double bonds, such as hydroxybenzoic acid, (meth) acrylic acid, etc. Examples thereof include compounds obtained by copolymerizing unsaturated carboxylic acid and a compound having a phenolic hydroxyl group such as hydroxyphenyl (meth) acrylate and having a polymerizable double bond.

  In addition, the compound having a phenolic hydroxyl group and a carboxyl group may be one kind of compound selected from the above-described compounds or a mixture of two or more kinds of compounds.

  The compounding ratio of the compound having a phenolic hydroxyl group and a carboxyl group in the inkjet ink is the phenolic hydroxyl group and the carboxyl group of the compound having a phenolic hydroxyl group and a carboxyl group with respect to the epoxy equivalent of the cyclopentadiene type epoxy resin (A). It is preferable that the proportion of the equivalent amount is 0.5 to 2.0. More preferably, when the blending is 0.8 to 1.2, the curability, the heat resistance of the cured product, the electrical characteristics, etc. are improved.

  The compound (B) may be a compound having the above-described phenolic hydroxyl group, a compound having the above-described carboxyl group, and a compound having a phenolic hydroxyl group and a carboxyl group.

1.3 Diluent (C)
The ink of the present invention may contain a diluent (C) in order to improve and maintain various properties. Although the diluent (C) of this invention is not specifically limited, It is preferable that the viscosity of 25 degreeC measured with the E-type viscosity meter is 0.1-100 mPa * s, and it is 0.1-50 mPa * s. More preferably, it is 0.1-10 mPa * s. Specific examples of the diluent (C) include a monomer having a radical polymerizable group and a solvent. As the monomer having a radical polymerizable group, a monofunctional or polymonofunctional monomer is preferable.

1.3 (1) Monofunctional polymerizable monomer If the monomer having a radical polymerizable group is a monofunctional polymerizable monomer, jetting properties in an ink jet printing system are particularly preferable.

Specific examples of the monofunctional polymerizable monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 1,4-cyclohexanedimethanol mono (meth) acrylate. N-hydroxyethyl (meth) acrylamide, glycidyl (meth) acrylate, 3,4-epoxycyclohexyl (meth) acrylate, methyl glycidyl (meth) acrylate, 3-methyl-3- (meth) acryloxymethyl oxetane, 3- Ethyl-3- (meth) acryloxymethyl oxetane, 3-methyl-3- (meth) acryloxyethyl oxetane, 3-ethyl-3- (meth) acryloxyethyl oxetane, p-vinylphenyl-3-ethyloxeta-3 -Ilmethyl A 2-phenyl-3- (meth) acryloxymethyl oxetane, 2-trifluoromethyl-3- (meth) acryloxymethyl oxetane, 4-trifluoromethyl-2- (meth) acryloxymethyl oxetane, (meth ) Acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) Acrylate, benzyl (meth) acrylate, styrene, methylstyrene, chloromethylstyrene, (3-ethyl-3-oxetanyl) methyl (meth) acrylate, N-cyclohexylmaleimide, N-phenylmaleimide, vinyltoluene, tricyclo [5.2 .1 0 ^2,6] decanyl (meth) acrylate, dicyclopentenyl oxyethyl (meth) acrylate, isobornyl (meth) acrylate, phenyl (meth) acrylate, glycerol mono (meth) acrylate, polystyrene macromonomer, polymethylmethacrylate macromonomer, 5-tetrahydrofurfuryloxycarbonylpentyl (meth) acrylate, (meth) acrylate of ethylene oxide adduct of lauryl alcohol, (meth) acrylic acid, crotonic acid, α-chloroacrylic acid, cinnamic acid, maleic acid, fumaric acid, Itaconic acid, citraconic acid, mesaconic acid, ω-carboxypolycaprolactone mono (meth) acrylate, succinic acid mono [2- (meth) acryloyloxyethyl], maleic acid mono [2- (meth) acrylate Liloyloxyethyl], cyclohexene-3,4-dicarboxylic acid mono [2- (meth) acryloyloxyethyl], (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide N, N-dimethylaminopropyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-acryloylmorpholine, N-phenylmaleimide, N-cyclohexylmaleimide, and tetrahydrofurfuryl methacrylate.

  These monofunctional polymerizable monomers may be a single compound or a mixture of two or more compounds. A monofunctional (meth) acrylate is more preferable as the monofunctional polymerizable monomer.

1.3 (2) The polyfunctional polymerizable monomer diluent (C) may be a polyfunctional polymerizable monomer.

  Specific examples of the polyfunctional polymerizable monomer include acid-modified epoxy (meth) acrylate, acid-modified (meth) acrylate, bisphenol F ethylene oxide-modified diacrylate, bisphenol A ethylene oxide-modified diacrylate, isocyanuric acid ethylene oxide-modified diacrylate, polyethylene glycol di Acrylate, dipropylene glycol diacrylate, polypropylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol diacrylate monostearate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol Diacrylate, 1,4-cyclohexanedimethanol diacrylate, 2-n-butyl-2-ethyl-1,3-pro Diol diacrylate, trimethylolpropane diacrylate, dipentaerythritol diacrylate, modified isocyanuric acid ethylene oxide modified di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol di (meth) acrylate monostearate, pentaerythritol tri (Meth) acrylate, trimethylolpropane di (meth) acrylate, dipentaerythritol di (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Bisphenol F ethylene oxide modified diacrylate, bisphenol A ethylene oxide modified diacrylate, polyester Lenglycol diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,4-cyclohexanedimethanol diacrylate, 2-n -Butyl-2-ethyl-1,3-propanediol diacrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, epichlorohydrin modified Trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, glycerol tri (meth) acrylate, epichlorohydride Modified glycerol tri (meth) acrylate, diglycerin tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate, ethylene oxide modified triphosphate Mention may be made of (meth) acrylate, tris [(meth) acryloxyethyl] isocyanurate, caprolactone-modified tris [(meth) acryloxyethyl] isocyanurate, urethane (meth) acrylate. Among them, dipropylene glycol diacrylate and bisphenol F ethylene oxide-modified diacrylate also have good heat resistance and photocuring characteristics.

  These polyfunctional polymerizable monomers may be a single compound or a mixture of two or more compounds. Moreover, polyfunctional (meth) acrylate is more preferable as the polyfunctional polymerizable monomer.

  The monomer having radical polymerizability as the diluent (C) may be a single compound or a mixture of two or more different compounds. For example, the diluent (C) may be a mixture of monofunctional (meth) acrylate and polyfunctional (meth) acrylate.

  Of these, at least one of tetrahydrofurfuryl methacrylate or dipropylene glycol diacrylate is excellent in compatibility with each component of the ink, has a good balance between low warpage and Tg, and has a viscosity of inkjet. It is more preferable because it can be lowered to a viscosity capable of being discharged.

  The content of the radically polymerizable monomer as the diluent (C) is preferably 15 to 85% by weight of the total amount of the ink because the balance between low warpage, heat resistance and jetting characteristics is improved, and more preferably 20 It is -80 weight%, More preferably, it is 25-75 weight%, Especially preferably, it is 30-70 weight%.

1.3 (3) A solvent may be used as the solvent diluent (C). When heating an ink jet head in an ink jet printing method, if a low boiling point solvent is contained in the ink, the solvent volatilizes, the ink viscosity increases, and the nozzle head of the ink jet head may become clogged. Therefore, a solvent having a boiling point of 100 to 300 ° C. is particularly preferable.

  Specific examples of the solvent having a boiling point of 100 to 300 ° C. include water, butyl acetate, butyl propionate, ethyl lactate, methyl oxyacetate, ethyl oxyacetate, butyl oxyacetate, methyl methoxyacetate, ethyl methoxyacetate, and butyl methoxyacetate. , Methyl ethoxy acetate, ethyl ethoxy acetate, methyl 3-oxypropionate, ethyl 3-oxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate Methyl 2-oxypropionate, ethyl 2-oxypropionate, propyl 2-oxypropionate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate, propyl 2-methoxypropionate, methyl 2-ethoxypropionate, 2- Ethyl toxipropionate, methyl 2-oxy-2-methylpropionate, ethyl 2-oxy-2-methylpropionate, methyl 2-methoxy-2-methylpropionate, ethyl 2-ethoxy-2-methylpropionate, pyrubin Methyl acetate, ethyl pyruvate, propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl 2-oxobutanoate, ethyl 2-oxobutanoate, dioxane, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tri Propylene glycol, 1,4-butanediol, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monome Ether ether, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol monobutyl ether acetate, ethylene glycol monobutyl ether acetate, cyclohexanone, cyclopentanone, diethylene glycol monomethyl ether, diethylene glycol monomethyl Ether acetate, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, polyethylene N-glycol methyl ethyl ether, toluene, xylene, anisole, γ-butyrolactone, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, or dimethylimidazolidinone.

  These solvents may be a single compound or a mixture of two or more compounds.

  When the content of the solvent as the diluent (C) is 0.1 to 10% by weight of the total amount of the ink, the balance between jetting and other characteristics in the ink jet printing method is good, and more preferably 0.2. It is -8 weight%, More preferably, it is 0.5-6 weight%, Most preferably, it is 1-5 weight%.

  The diluent (C) may be a single compound or a mixture of two or more compounds. For example, a mixture of a monofunctional polymerizable monomer and a solvent may be used.

1.4 Photopolymerization initiator (D)
The ink of the present invention may contain a photopolymerization initiator (D) in order to impart photocurability. A photoinitiator (D) will not be specifically limited if it is a compound which generate | occur | produces a radical by irradiation of an ultraviolet-ray or visible light. Preferable specific examples include acylphosphine oxide compounds and alkylphenone compounds.

Specific examples of the photopolymerization initiator (D) include benzophenone, Michler's ketone, 4,4′-bis (diethylamino) benzophenone, xanthone, thioxanthone, isopropylxanthone, 2,4-diethylthioxanthone, 2-ethylanthraquinone, acetophenone, 2 -Hydroxy-2-methylpropiophenone, 2-hydroxy-2-methyl-4'-isopropylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, isopropyl benzoin ether, isobutyl benzoin ether, 2,2-diethoxyacetophenone, 2 , 2-dimethoxy-2-phenylacetophenone, camphorquinone, benzanthrone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzi 2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 4,4′-di (t-butylperoxycarbonyl) benzophenone, 3,4,4′-tri (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (t -Hexylperoxycarbonyl) benzophenone, 3,3'-di (methoxycarbonyl) -4,4'-di (t-butylperoxycarbonyl) benzophenone, 3,4'-di (methoxycarbonyl) -4,3'-di (T-butylperoxycarbonyl) benzophenone, 4,4′-di (methoxycarbonyl) -3,3′-di (t-butylpe) Ruoxycarbonyl) benzophenone, 1,2-octanedione, 1- [4- (phenylthio) phenyl]-, 2- (o-benzoyloxime), 2- (4′-methoxystyryl) -4,6-bis ( Trichloromethyl) -s-triazine, 2- (3 ′, 4′-dimethoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (2 ′, 4′-dimethoxystyryl) -4, 6-bis (trichloromethyl) -s-triazine, 2- (2′-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4′-pentyloxystyryl) -4,6 -Bis (trichloromethyl) -s-triazine, 4- [p-N, N-di (ethoxycarbonylmethyl)]-2,6-di (trichloromethyl) -s-triazine, 1,3-bis (Trichloromethyl) -5- (2′-chlorophenyl) -s-triazine, 1,3-bis (trichloromethyl) -5- (4′-methoxyphenyl) -s-triazine, 2- (p-dimethylaminostyryl) ) Benzoxazole, 2- (p-dimethylaminostyryl) benzthiazole, 2-mercaptobenzothiazole, 3,3′-carbonylbis (7-diethylaminocoumarin), 2- (o-chlorophenyl) -4,4 ′, 5 , 5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetrakis (4-ethoxycarbonylphenyl) -1,2 ′ -Biimidazole, 2,2'-bis (2,4-dichlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis ( , 4-dibromophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis (2,4,6-trichlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole, 3- (2-methyl-2-dimethylaminopropionyl) carbazole, 3,6-bis (2-methyl-2-morpholinopropionyl) -9-n -Dodecylcarbazole, 1-hydroxycyclohexyl phenyl ketone, bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) Examples include titanium, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, or 2,4,6-trimethylbenzoyldiphenylphosphine oxide. Can.

  The photopolymerization initiator (D) may be a single compound or a mixture of two or more compounds.

  The content of the photopolymerization initiator (D) is preferably 0.5 to 20% by weight of the total amount of the ink because the ink has high sensitivity to ultraviolet rays, and more preferably 1 to 20% by weight. More preferably, it is 2 to 20% by weight.

1.5 Other components In order to further improve various properties, the ink of the present invention is an epoxy resin (other epoxy resins) other than melamine resin, dicyclopentadiene type epoxy resin, epoxy curing agent, surfactant, difficulty A flame retardant, a colorant, a polymerization inhibitor, and the like may be included.

1.5 (1) Melamine resin The ink of the present invention may contain a melamine resin, for example, in order to improve the heat resistance and chemical resistance of the resulting cured film.

  Specific examples of the melamine resin include melamine, methylol melamine, etherified methylol melamine, benzoguanamine, methylol benzoguanamine, etherified methylol benzoguanamine, and condensates thereof. Of these, etherified methylol melamine is preferred because of its good chemical resistance, and a mixture of etherified methylol melamine and its condensate is commercially available as Nicalak MW-30 (trade name) manufactured by Sanwa Chemical Co., Ltd. ing. The melamine resin used in the ink may be a single compound or a mixture of two or more compounds.

  When the melamine resin is contained in the ink in an amount of 1 to 20% by weight, it is preferable because the cured film of the resulting ink has high chemical resistance, more preferably 2 to 15% by weight, and more preferably 3 to 10% by weight. More preferably.

1.5 (2) Other Epoxy Resins The ink of the present invention can be used, for example, in order to improve the heat resistance and chemical resistance of the cured film obtained, other epoxy other than dicyclopentadiene type epoxy resin (A). A resin may be included.

  Specific examples of the other epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, glycidyl ester type epoxy resins, and alicyclic epoxy resins.

  Other commercially available epoxy resins include Epicoat 807, 815, 825, 827, 828, 190P, 191P, 1004, 1256 (trade name; manufactured by Japan Epoxy Resins Co., Ltd.), Araldite CY177, CY184 (trade name; manufactured by Huntsman Advance Material), Celoxide 2021P, EHPE-3150 (trade name; manufactured by Daicel Chemical Industries, Ltd.), or Techmore VG3101L (trade name; manufactured by Mitsui Chemicals, Inc.) Can be mentioned.

  The other epoxy resin used in the ink may be a single compound or a mixture of two or more compounds.

  When the other epoxy resin content is 1 to 20% by weight of the solid content of the ink, the heat resistance and chemical resistance are improved, more preferably 1 to 10% by weight, still more preferably 1 to 7%. % By weight.

1.5 (3) When an epoxy curing agent or other epoxy resin is included, for example, an epoxy curing agent may be further included in order to further improve the chemical resistance of the cured film. As the epoxy curing agent, an acid anhydride curing agent, a polyamine curing agent, a catalytic curing agent, and the like are preferable.

  Specific examples of the acid anhydride curing agent include maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrotrimellitic anhydride, phthalic anhydride, A merit acid anhydride or a styrene-maleic anhydride copolymer may be mentioned.

  Specific examples of the polyamine curing agent include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dicyandiamide, polyamidoamine (polyamide resin), ketimine compound, isophoronediamine, m-xylenediamine, m-phenylenediamine, 1,3- Bis (aminomethyl) cyclohexane, N-aminoethylpiperazine, 4,4′-diaminodiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, or diaminodiphenylsulfone. Specific examples of the catalyst type curing agent include a tertiary amine compound or an imidazole compound.

  Specific examples of polycarboxylic acid-based curing agents include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride, hexachloro Examples include endomethylenetetrahydrophthalic anhydride or methyl-3,6-endomethylenetetrahydrophthalic anhydride.

The epoxy curing agent used in the ink may be a single compound or a mixture of two or more compounds.
The content of the epoxy curing agent is preferably 0.5 to 50% by weight of the total amount of the ink because etching resistance or plating resistance is improved, and more preferably 0.5 to 50% in view of balance with other characteristics. It is 40% by weight, more preferably 0.5 to 30% by weight.

1.5 (4) Surfactant The ink of the present invention may contain a surfactant in order to improve, for example, wettability to the base substrate and film surface uniformity of the cured film. As the surfactant, a silicon surfactant, an acrylic surfactant, a fluorine surfactant, or the like is used.

  Examples of commercially available surfactants include silicon surfactants such as Byk-300, 306, 335, 310, 341, 344, and 370 (trade name; manufactured by Big Chemie). , Byk-354, 358, and 361 (trade name; manufactured by Big Chemie Co., Ltd.) and the like, DFX-18, Footage 250, or 251 (trade name; Neos Co., Ltd.) And Fluorosurfactant such as MegaFuck F-479 (trade name; manufactured by DIC Corporation).

  The surfactant used in the ink may be a single compound or a mixture of two or more compounds.

  The surfactant content is preferably 0.001 to 1% by weight of the solid content of the ink because the uniformity of the surface of the cured film is improved, and more preferably 0.001 in view of the balance with other characteristics. It is -0.1 weight%, More preferably, it is 0.001-0.05 weight%.

1.5 (5) Flame retardant A flame retardant may be included to impart flame retardancy to the ink of the present invention. The flame retardant is not particularly limited, such as a phosphorus compound, a halogen compound, and an inorganic compound, but is preferable because the phosphorus compound has little influence on the environment.

  In the above phosphorus compound, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl phenyl phosphate, 2-ethylhexyl diphenyl phosphate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10 oxide, Examples include 10- (2,5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide, condensed 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10 oxide, and the like. .

  Examples of the halogen compound include: tetrabromobisphenol A, decabromodiphenyl oxide, hexabromocyclodecane, 2,4,6-tribromophenol, ethylenebistetrabromophthalimide, brominated polystyrene, tetrabromobisphenol A polycarbonate, Brominated epoxy resins, brominated (meth) acrylates, chlorinated paraffins, cycloaliphatic chlorinated compounds and the like are listed.

  Examples of the inorganic compound include aluminum hydroxide, magnesium hydroxide, antimony trioxide, borate, zinc stannate, molybdenum oxide, zinc molybdate, calcium molybdate, guanidine nitride, antimony pentoxide, and the like.

  The flame retardant used in the ink may be a single compound or a mixture of two or more compounds.

  The flame retardant content varies depending on the flame retardant, so the range cannot be limited. However, when the ink solid content is 1 to 50% by weight, the resulting cured film has high flame resistance (UL-94 combustion). Test method VTM-0) can be applied, which is preferable.

1.5 (6) Colorant The ink of the present invention may contain a colorant , for example, in order to facilitate discrimination from the substrate when inspecting the state of the cured film. As the colorant, dyes and pigments are preferable.

  The colorant used in the ink may be a single compound or a mixture of two or more compounds.

  It is preferable that the content of the colorant is 0.1 to 5% by weight of the solid content of the ink because the cured film can be easily inspected. %, More preferably 0.1 to 0.5% by weight.

1.5 (7) Polymerization inhibitor The ink of the present invention may contain a polymerization inhibitor , for example, in order to improve storage stability. Specific examples of the polymerization inhibitor include 4-methoxyphenol, hydroquinone, or phenothiazine. Among these, phenothiazine is preferable because the change in viscosity is small even during long-term storage.

  The polymerization inhibitor used in the ink may be a single compound or a mixture of two or more compounds.

  It is preferable that the content of the polymerization inhibitor is 0.01 to 1% by weight of the ink solid content because the change in viscosity is small even during long-term storage. It is 01 to 0.5% by weight, more preferably 0.01 to 0.1% by weight.

1.6 Ink Viscosity The ink of the present invention preferably has a viscosity at 25 ° C. of 1 to 200 mPa · s as measured with an E-type viscometer because application characteristics (such as jetting accuracy) by ink jet printing are improved. . The viscosity of the ink at 25 ° C. is more preferably 2 to 50 mPa · s, and further preferably 3 to 20 mPa · s.

  When an ink having a viscosity at 25 ° C. of 30 mPa · s or more is used, more stable ejection can be achieved by heating the inkjet head to lower the viscosity during ejection. When jetting by heating the inkjet head, the viscosity of the inkjet ink at a heating temperature (preferably 40 to 120 ° C.) is preferably 1 to 30 mPa · s, more preferably 2 to 25 mPa · s. ˜20 mPa · s is particularly preferred.

  When heating the ink jet head, it is preferable to use an ink containing no solvent. In that case, the viscosity of the ink is preferably adjusted by appropriately selecting the type and content of the diluent (C). When the ink jet head is not heated, the viscosity of the ink can be adjusted by adding a solvent of 10% by weight or less of the total amount of the ink.

1.7 Ink Storage When the ink of the present invention is stored at -20 to 20 ° C, the viscosity change during storage is small and the storage stability is good.

2. Application of Ink by Inkjet Printing Method The ink of the present invention can be applied using a known inkjet printing method. As an inkjet coating method, for example, a method in which mechanical energy is applied to ink to eject (apply) ink from an inkjet head (so-called piezo method), and a coating method in which thermal energy is applied to ink to apply ink (So-called bubble jet (registered trademark) system).

  By using the inkjet coating method, the ink can be applied in a predetermined pattern. As a result, ink can be applied only to necessary portions, and the cost can be reduced as compared with the photolithography method.

  A preferable application unit for performing application using the ink of the present invention includes, for example, an ink jet unit provided with an ink containing portion for containing these inks and an ink jet head. Examples of the ink jet unit include an ink jet unit that causes thermal energy corresponding to a coating signal to act on ink and generates ink droplets by the energy.

  As an inkjet head, for example, it has a heating part liquid contact surface containing a metal and / or a metal oxide. Specific examples of the metal and / or metal oxide include metals such as Ta, Zr, Ti, Ni, and Al, and oxides of these metals.

  As a preferable coating apparatus for performing coating using the ink of the present invention, for example, energy corresponding to a coating signal is given to ink in a room of an ink jet head having an ink storage section in which ink is stored, and the energy An apparatus for generating ink droplets is exemplified.

  The ink jet coating apparatus is not limited to the one in which the ink jet head and the ink container are separated, and may be one in which they are integrated so as not to be separated. The ink container is integrated with the ink jet head in a separable or non-separable manner and mounted on the carriage, and is provided at a fixed portion of the apparatus so that the ink is supplied to the ink jet head through an ink supply member, for example, a tube. It may be in the form of supplying.

  In addition, the inkjet discharge (application) temperature is preferably 10 to 120 ° C., and the viscosity of the ink at the application temperature is preferably 1 to 30 mPa · s.

3. Formation of Cured Film The cured film of the present invention is obtained by applying the ink described above to the substrate surface by an ink jet printing method, and then irradiating the ink with light such as ultraviolet rays or visible rays as necessary.

In the case of irradiating ultraviolet rays, the amount of ultraviolet rays to be irradiated depends on the composition of the ink, but it is 10 to 1 as measured with an integrating light meter UIT-201 equipped with a photoreceiver UVD-365PD manufactured by USHIO INC. preferably about 000mJ / cm ^2, preferably about 20~800mJ / cm ^2, about 40~500mJ / cm ² is more preferred. Moreover, 200-450 nm is preferable, the wavelength of the ultraviolet-ray to irradiate is more preferable, 220-430 nm is more preferable, 250-400 nm is further more preferable.

  In addition, if necessary, the cured film cured by light irradiation may be further heated and fired. In particular, it is preferable to heat at 100 to 250 ° C. for 10 to 60 minutes, and at 120 to 230 ° C. for 10 to 10 minutes. Heating for 60 minutes is more preferable, and heating at 150 to 200 ° C. for 10 to 60 minutes is more preferable.

  The “substrate” that can be used in the present invention is not particularly limited as long as it can be an object to which ink is applied. The shape is not limited to a flat plate shape, and may be a curved surface shape.

  The material constituting the substrate is not particularly limited. For example, polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyolefin resins such as polyethylene and polypropylene, polyvinyl chloride, fluorine resins, and acrylic resins. , Plastic film such as polyamide, polycarbonate, polyimide, cellophane, acetate, metal foil, laminated film of polyimide and metal foil, glassine paper, parchment paper, or polyethylene, clay binder, polyvinyl alcohol, starch, carboxymethyl cellulose Examples thereof include paper and glass treated with (CMC) and the like.

  The materials constituting these substrates may further include pigments, dyes, antioxidants, deterioration inhibitors, fillers, ultraviolet absorbers, antistatic agents and / or electromagnetic waves, as long as the effects of the present invention are not adversely affected. An additive such as an inhibitor may be included. Further, a material different from the substrate may be formed on a part of the surface of the substrate.

  The use of the substrate is not particularly limited, but the cured film obtained from the ink jet ink of the present invention is excellent in plating resistance, heat resistance, flame retardancy, adhesion, and flexibility, so that a metal circuit is formed on the substrate surface. It is preferably used for the production of an electronic circuit board or the like having Although the metal which forms a circuit is not specifically limited, Gold, silver, copper, aluminum, or ITO is preferable.

  Although the thickness of a board | substrate is not specifically limited, Usually, it is about 10 micrometers-2 mm, Although it adjusts suitably by the objective to use, 15-500 micrometers is preferable and 20-200 micrometers is more preferable.

  If necessary, the surface on which the cured film of the substrate is formed may be subjected to easy adhesion treatment such as water repellent treatment, corona treatment, plasma treatment, or blast treatment, or an easy adhesion layer or color filter protective film may be provided on the surface. May be.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited by these.

<Preparation of ink and cured film pattern formation substrate>
First, the ink according to Examples 1 to 3 and Comparative Examples 1 to 4 and the cured film pattern formation substrate obtained therefrom will be described. The viscosity of each ink was measured at 25 ° C. using an E-type viscometer (TV-22 manufactured by Toki Sangyo Co., Ltd.).

[Example 1]
As dicyclopentadiene type epoxy resin (A), HP-7200HH (trade name; manufactured by DIC Corporation), and as compound (B), Marcalinker MS-2G (trade name; Maruzen Petrochemical Co., Ltd.), which is polyvinylphenol, is used. Co., Ltd., weight average molecular weight: 4,000-6,000), as diluent (C), tetrahydrofurfuryl methacrylate SR-203 (trade name; manufactured by Sartomer Co., Ltd.), 2-hydroxyethyl methacrylate, SR-508 (trade name; manufactured by Sartomer Co., Ltd.), which is dipropylene glycol diacrylate, and DAROCUR TPO (trade name, which is 2,4,6-trimethylbenzoyldiphenylphosphine oxide) as a photopolymerization initiator (D). Ciba Specialty Chemicals Co., Ltd.), flame retardant (E), condensation 9, 0-dihydro-9-oxa-10-phosphaphenanthrene-10 oxide, HFA-3003 (trade name; manufactured by Showa Polymer Co., Ltd.), and phenothiazine as a polymerization inhibitor were mixed and dissolved in the following composition ratio. Then, it filtered with the membrane filter (1 micrometer) made from PTFE, and the ink 1 was prepared.
(A) HP-7200HH 10.00 g
(B) Marcalinker MS-2G 4.50 g
(C) SR-203 50.00 g
(C) 2-hydroxyethyl methacrylate 7.50 g
(C) SR-508 90.00g
(D) DAROCUR TPO 20.00g
(Others) Phenothiazine 0.05g
The viscosity of the ink 1 at 25 ° C. was 16.0 mPa · s.

Ink discharge conditions Ink 1 is injected into an ink jet cartridge, which is mounted on an ink jet apparatus (DMP-2831 manufactured by FUJIFILM Dimatix), and a 10 pl head (DMC-11610) is used to discharge ink (piezo voltage). A predetermined pattern was formed on Kapton 50H (manufactured by Toray DuPont Co., Ltd.), which is a polyimide film (thickness: 12.5 μm), under discharge conditions of 16 V, head temperature of 25 ° C., drive frequency of 5 kHz, and number of coatings of 1 time. .

Curing conditions for coating film A substrate on which the coating film of ink 1 is patterned is UV exposed (500 mJ / cm ² ), further baked at 200 ° C. for 30 minutes, and cured to a thickness of 10 μm. A substrate 1 on which a film pattern was formed was obtained. The light source used for UV exposure was an ultra-high pressure mercury lamp, and the exposure amount was measured with an integrated light meter UIT-201 equipped with a photoreceiver UVD-365PD manufactured by USHIO INC.

<Evaluation of ink and cured film>
Evaluation of jetting characteristics The state of discharge was observed under the above discharge conditions. The case where the liquid column during jetting was discharged in the vertical direction and no satellite was generated was indicated as “◯”, and the case where the liquid column was in contact with the adjacent liquid column or a satellite was generated was indicated as “X”. The results are shown in Table 1.

Evaluation of photocurability In order to examine the photocurability, the substrate on which the ink was applied was subjected to UV exposure (500 mJ / cm ² ), and then touched with a finger to confirm whether or not tackiness occurred. The case where tackiness did not occur was indicated as “◯”, and the case where tackiness occurred was denoted as “x”. The results are shown in Table 1.
The light source used for UV exposure was an ultra-high pressure mercury lamp, and the exposure amount was measured with an integrated light meter UIT-201 equipped with a photoreceiver UVD-365PD manufactured by USHIO INC.

Evaluation of warpage In order to evaluate warpage, ink is printed in a 3 cm x 3 cm square on a Kapton 50H Toray DuPont Co., Ltd., which is a 4 cm x 4 cm polyimide film (thickness 12.5 µm). Was performed (film thickness 10 μm), and then UV exposure (500 mJ / cm ² ) was performed. After UV exposure, the ink-coated polyimide film was heat-cured (200 ° C. × 30 minutes). After heat curing, after naturally cooling for 1 hour, the height of the four ends of the polyimide film was measured with a ruler with the ink application surface as the upper surface. When the average value of the heights at the four ends (n = 4) is 3 mm or less, “◯” is given, the case of 3-10 mm is “△”, and when the film cannot be measured due to curling, “x” is given. Table 1 shows the results. The light source used for UV exposure was an ultra-high pressure mercury lamp, and the exposure amount was measured with an integrated light meter UIT-201 equipped with a photoreceiver UVD-365PD manufactured by USHIO INC.

Here, the used polyimide film (Kapton 50H) will be described. According to the catalog of Toray DuPont Co., Ltd., it is a polyimide obtained by condensation polymerization of an aromatic tetrabasic acid and an aromatic diamine, and its mechanical properties are as follows. Density = 1.42 g · cm ⁻³ (Measurement method: ASTM D-1505), Tensile strength = 350 MPa (Measurement method: JIS C 2318), Tensile elongation = 85% (Measurement method: JIS C 2318), Tensile modulus = 3.50 GPa (measurement method: ASTM D-882), tear propagation resistance = 3.8 N · mm ⁻¹ (measurement method = JIS P 8116), end crack resistance = 200 N · 20 mm ⁻¹ (measurement method: JIS C 2318) ), 3% elongation stress = 80 MPa (measurement method: JIS C 2318), 50% elongation stress = 260 MPa (measurement method: JIS C 2318), impact strength = 240 kg · cm · mm ⁻¹ (measurement method: JIS K 6745) ), Breaking strength = 5.3 MPa (measurement method: ASTM D774).

Measurement of Glass Transition Temperature (Tg) Tan δ was measured using a dynamic viscoelasticity measuring device DVE-V4 (manufactured by UBM), and the point at which tan δ was maximized was defined as the glass transition temperature. The cured film is a polyimide film (thickness 50 μm) on Kapton 200H (manufactured by Toray DuPont Co., Ltd.) with an applicator (film thickness of about 300 μm), and UV exposure (500 mJ / cm ² ) is performed. Further, it was prepared by baking at 200 ° C. for 30 minutes. The prepared cured film was peeled off from the polyimide film, cut into a size of 5 mm × 22 mm, and used as a test piece. The light source used for UV exposure was an ultra-high pressure mercury lamp, and the exposure amount was measured with an integrated light meter UIT-201 equipped with a photoreceiver UVD-365PD manufactured by USHIO INC. The measurement conditions for the glass transition temperature were a fundamental frequency of 10 Hz and a temperature increase rate of 5 ° C./min. The results are shown in Table 1.

Evaluation of Solder Heat Resistance of Cured Film In order to evaluate the solder heat resistance of the cured film, a rosin-based flux (trade name: NS-829, manufactured by Nippon Superior Co., Ltd.) is applied to the surface of the substrate 1 described above. It was immersed in a 260 ° C. solder bath for 30 seconds, and it was examined by microscopic observation whether peeling or swelling occurred. The case where no peeling or swelling occurred was indicated by “◯”, and the case where slight peeling or swelling occurred was indicated by “X”. The results are shown in Table 1.

[Example 2]
Ink 2 was prepared in the same manner as in Example 1, except that hydroxyphenyl methacrylate was used as compound (B) instead of Marcalinker M-2G and the composition was as follows.
(A) HP-7200HH 10.00 g
(B) Hydroxyphenyl methacrylate 6.50 g
(C) SR-203 50.00 g
(C) SR-508 10.00g
(D) DAROCUR TPO 10.00g
(Others) Phenothiazine 0.05g
The viscosity of the ink 2 at 25 ° C. was 17.2 mPa · s.
A substrate 2 on which a cured film pattern having a thickness of 10 μm was formed using the ink 2 was obtained in the same manner as in Example 1. Moreover, the ink 2 and its cured film were evaluated by the above-mentioned method. The results are shown in Table 1.

[Example 3]
Ink 3 was prepared in the same manner as in Example 2 except that monohydroxyethyl methacrylate phthalate was used as the compound (B) instead of Marcalinker M-2G and the composition was as follows.
(A) HP-7200HH 10.00 g
(B) Phthalic acid monohydroxyethyl methacrylate 10.00 g
(C) SR-203 50.00 g
(C) SR-508 10.00g
(D) DAROCUR TPO 10.00g
(Others) Phenothiazine 0.05g
The viscosity of the ink 3 at 25 ° C. was 17.9 mPa · s.
A substrate 3 on which a cured film pattern having a thickness of 10 μm was formed using the ink 3 was obtained in the same manner as in Example 1. Moreover, the ink 3 and its cured film were evaluated by the above-mentioned method. The results are shown in Table 1.

[Comparative Example 1]
Ink 4 was prepared in the same manner as in Example 2 except that HP-7200HH was not used and the composition was as follows.
(B) Hydroxyphenyl methacrylate 6.50 g
(C) SR-203 50.00 g
(C) SR-508 10.00g
(D) DAROCUR TPO 10.00g
(Others) Phenothiazine 0.05g
The viscosity of the ink 4 at 25 ° C. was 3.0 mPa · s.
A substrate 4 on which a cured film pattern having a thickness of 10 μm was formed using the ink 4 was obtained in the same manner as in Example 1. Moreover, the ink 4 and its cured film were evaluated by the above-mentioned method. The results are shown in Table 1.

[Comparative Example 2]
Ink 5 was prepared in the same manner as in Example 2 except that EP828EL (manufactured by Japan Epoxy Resin Co., Ltd.) which is not a dicyclopentadiene type epoxy resin was used instead of HP-7200HH, and the composition was as follows.
EP828EL 10.00g
(B) Hydroxyphenyl methacrylate 6.50 g
(C) SR-203 50.00 g
(C) SR-508 10.00g
(D) DAROCUR TPO 10.00g
(Others) Phenothiazine 0.05g
The viscosity of the ink 5 at 25 ° C. was 10.2 mPa · s.
A substrate 5 on which a cured film pattern having a thickness of 10 μm was formed using the ink 5 in the same manner as in Example 1. Moreover, the ink 5 and its cured film were evaluated by the above-mentioned method. The results are shown in Table 1.

[Comparative Example 3]
Except that HPR-7200HH and hydroxyphenyl methacrylate were replaced with IRR214-K (produced by Daicel Cytec Co., Ltd.), which is a dicyclopentadiene type diacrylate, the composition was as follows, and the same procedure as in Example 2 was performed. Ink 6 was prepared.
IRR214-K 10.00g
(C) SR-203 50.00 g
(C) SR-508 10.00g
(D) DAROCUR TPO 10.00g
(Others) Phenothiazine 0.05g
The viscosity of the ink 6 at 25 ° C. was 13.3 mPa · s.
A substrate 6 on which a cured film pattern having a thickness of 10 μm was formed using the ink 6 was obtained in the same manner as in Example 1. Moreover, the ink 6 and its cured film were evaluated by the method described above. The results are shown in Table 1.

[Comparative Example 4]
Ink 7 was prepared with the same composition as in Example 2 except that hydroxyphenyl methacrylate was not used and the composition was as follows.
(A) HP-7200HH 10.00 g
(C) SR-203 50.00 g
(C) SR-508 10.00g
(D) DAROCUR TPO 10.00g
(Others) Phenothiazine 0.05g
The viscosity of the ink 7 at 25 ° C. was 16.0 mPa · s.
A substrate 7 on which a cured film pattern having a thickness of 10 μm was formed using the ink 7 was obtained in the same manner as in Example 1. Moreover, the ink 7 and its cured film were evaluated by the above-mentioned method. The results are shown in Table 1.

  As is clear from the results shown in Table 1, in all of Examples 1 to 3 and Comparative Examples 1 to 4 according to the present invention, the liquid column at the time of jetting was ejected in the vertical direction, no satellite was generated, and the ink The dischargeability of was good.

  In Comparative Example 4 which does not include the compound containing a phenolic hydroxyl group and the compound (B) containing a compound containing a carboxyl group, the photocurability was poor and the tackiness was present, so the subsequent evaluation was stopped.

  In Comparative Example 1 not containing a dicyclopentadiene type epoxy resin, the warpage was good, but the glass transition temperature was low and the solder heat resistance was poor.

  In Comparative Example 2 in which a bisphenol A type epoxy resin was used instead of the dicyclopentadiene type epoxy resin, the warpage was good, but the glass transition temperature was low and the solder heat resistance was poor.

  In Comparative Example 3 in which dicyclopentadiene type diacrylate was used instead of dicyclopentadiene type epoxy resin, the glass transition temperature was 90 ° C. or higher and the solder heat resistance was good, but the warpage was slightly poor. Warping up was observed at the four edges of the substrate.

As described above, according to the present invention, it is possible to obtain an ink jet ink with reduced ink ejection properties, photocurability and warpage, excellent solder heat resistance, and high glass transition temperature.

  The ink-jet ink of the present invention can be used for display elements and electronic circuit boards, for example.

Claims (21)

  A photocurable inkjet ink containing a dicyclopentadiene-type epoxy resin (A), the inkjet ink being applied to the center of a 4 cm square square polyimide film (thickness 12.5 μm). The average of the warp heights at the four ends of the polyimide film having a cured film (film thickness 10 μm) obtained by forming a 3 cm square square coating film and curing the coating film with light or heat A photocurable inkjet ink having a value of 3 mm or less and a glass transition temperature of a cured film obtained from the photocurable inkjet ink of 90 ° C. or more.   The dicyclopentadiene type epoxy resin (A) is an epoxy resin having a dicyclopentadiene skeleton having at least one glycidyl ether bond and at least one dicyclopentadienyl group in one molecule. The photocurable inkjet ink according to 1. The photocurable inkjet ink according to claim 1 or 2, wherein the dicyclopentadiene type epoxy resin (A) is represented by the following formula (1).

Wherein R ¹ , R ² and R ³ are each independently an organic group having 1 to 10 carbon atoms, and R ⁴ , R ⁵ and R ⁶ are independently hydrogen, alkyl having 1 to 12 carbon atoms. , Or halogen, and n is an integer of 0 or more and 10) The photocurable inkjet ink according to any one of claims 1 to 3, wherein the dicyclopentadiene type epoxy resin (A) is represented by the following formula (2).

(Where n is an integer from 0 to 10)   Furthermore, the photocurable inkjet ink of any one of Claims 1-4 containing the compound (B) characterized by having a phenolic hydroxyl group and / or a carboxyl group.   6. The photocurable inkjet according to claim 5, wherein the compound (B) is any one of a compound having a radical polymerizable double bond or an oligomer or a polymer obtained from a compound having a radical polymerizable double bond. ink.   The compound (B) is polyvinylphenol, or at least one of hydroxyphenyl (meth) acrylate, monohydroxyethyl phthalate (meth) acrylate, and monohydroxyethyl tetrahydrophthalate (meth) acrylate according to claim 5 or 6. The photocurable inkjet ink as described.   Furthermore, the photocurable inkjet ink as described in any one of Claims 1-7 containing a diluent (C).   The photocurable inkjet ink according to claim 8, wherein the diluent (C) has a viscosity at 25 ° C. of 0.1 to 100 mPa · s.   The photocurable inkjet ink according to claim 8 or 9, wherein the diluent (C) is a monofunctional (meth) acrylate or a polyfunctional (meth) acrylate.   Furthermore, the photocurable inkjet ink as described in any one of Claims 1-10 containing a photoinitiator (D).   The photocurable inkjet ink according to claim 11, wherein the photopolymerization initiator (D) is at least one compound selected from the group consisting of acylphosphine oxides and alkylphenone compounds.   The dicyclopentadiene type epoxy resin (A) is an epoxy resin represented by the formula (1), and the compound (B) is selected from the group consisting of polyvinylphenol, hydroxyphenyl (meth) acrylate, and monohydroxyethyl methacrylate phthalate. At least one selected, and the diluent (C) is at least one selected from the group consisting of tetrahydrofurfuryl methacrylate and dipropylene glycol diacrylate, and the photopolymerization initiator (D) is 2, 4, 6 The photocurable inkjet ink according to claim 1, which is trimethylbenzoyldiphenylphosphine oxide and contains phenothiazine as a polymerization inhibitor.   The photocurable inkjet ink according to claim 1, wherein the viscosity at 25 ° C. is 1 to 200 mPa · s.   The photocurable inkjet ink according to claim 1, wherein the viscosity at 25 ° C. is 1 to 30 mPa · s.   The cured film formation method of apply | coating the photocurable inkjet ink as described in any one of Claims 1-15, and making it harden | cure by irradiating light to a coating film.   The cured film formation method of hardening the cured film of Claim 16 by further heating.   A cured film obtained from the photocurable inkjet ink according to claim 1.   The cured film of Claim 18 currently formed in pattern shape.   An electronic circuit board, wherein the cured film according to claim 18 or 19 is formed on a board.   An electronic component comprising the electronic circuit board according to claim 20.