JP2012087284A - Curable composition for inkjet and method for producing printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable composition for inkjet, which is a curable composition applied by means of an inkjet method and has a long pot life even in the environment within an inkjet device that is heated to at least 50°C in spite of including a compound having a cyclic ether group.SOLUTION: The curable composition for inkjet is applied by means of an inkjet method and is cured by irradiation of light and application of heat. The curable composition for inkjet includes a polyfunctional compound having at least two (meth)acryloyl groups, a photopolymerization initiator, a compound having a cyclic ether group and a curing agent. The curing agent is a dicyandiamide particle having a median diameter of 5 μm or less.

Description

  The present invention relates to a curable composition for inkjet that is applied by an inkjet method, and is formed from an curable composition for inkjet that is suitably used for forming a resist pattern on a substrate, and the curable composition for inkjet. The present invention relates to a method for manufacturing a printed wiring board having a resist pattern.

  Conventionally, a printed wiring board in which a solder resist pattern, which is a patterned solder resist film, is formed on a substrate on which wiring is provided on the upper surface is often used. With the miniaturization and high density of electronic devices, printed circuit boards are required to have a finer solder resist pattern.

  As a method for forming a fine solder resist pattern, a method of applying a solder resist composition by an ink jet method has been proposed. In the inkjet method, the number of steps is smaller than in the case of forming a solder resist pattern by a screen printing method. For this reason, the solder resist pattern can be easily and efficiently formed by the inkjet method.

  When the solder resist composition is applied by an inkjet method, it is required that the viscosity at the time of application is low to some extent. On the other hand, in recent years, an inkjet apparatus capable of printing by heating to 50 ° C. or higher has been developed. By heating the solder resist composition to 50 ° C. or higher in the ink jet apparatus, the viscosity of the solder resist composition becomes relatively low, and the ejectability of the solder resist composition using the ink jet apparatus is further enhanced. be able to.

  Also, a solder resist composition that can be applied by an ink jet method is disclosed in Patent Document 1 below. Patent Document 1 below discloses inkjet curing comprising a monomer having a (meth) acryloyl group and a thermosetting functional group, a photoreactive diluent having a weight average molecular weight of 700 or less, and a photopolymerization initiator. A sex composition is disclosed. The viscosity of the curable composition for inkjet at 25 ° C. is 150 mPa · s or less.

WO2004 / 099272A1

  The viscosity of the curable composition for inkjet described in Patent Document 1 is relatively low. For this reason, the curable composition for inkjet described in Patent Document 1 can be coated on a substrate by an inkjet method.

  However, since the curable composition for inkjet described in Patent Document 1 contains a monomer having a (meth) acryloyl group and a thermosetting functional group, there is a problem that the pot life under an environment of 50 ° C. or higher is short. is there.

  For example, when an inkjet curable composition is ejected by an inkjet device, the inkjet curable composition generally remains in the inkjet device for a certain period of time after being supplied into the inkjet device. On the other hand, the temperature in the ink jet apparatus may be heated to 50 ° C. or higher in order to improve the ejection property. In the curable composition for inkjet described in Patent Document 1, the composition is cured in an inkjet apparatus heated to 50 ° C. or more, and the viscosity of the composition is increased. It can be difficult.

  Furthermore, the conventional inkjet curable composition also has a problem that the cured product after curing has low heat resistance and insulation reliability.

  An object of the present invention is a curable composition that is applied by an ink jet method, and includes a compound having a cyclic ether group, and is potted even in an environment in an ink jet apparatus that is heated to 50 ° C. or higher. It is to provide a curable composition for inkjet having a long life and a method for producing a printed wiring board using the curable composition for inkjet.

  Another object of the present invention is to provide a curable composition for inkjet which is excellent in heat resistance and insulation reliability of a cured product after curing, and a method for producing a printed wiring board using the curable composition for inkjet. It is to be.

  According to a wide aspect of the present invention, there is provided a curable composition for inkjet which is applied by an inkjet method and is cured by irradiation with light and application of heat, and is a polyfunctional compound having two or more (meth) acryloyl groups. An inkjet curable composition comprising a compound, a photopolymerization initiator, a compound having a cyclic ether group, and a curing agent, wherein the curing agent is dicyandiamide particles having a median diameter of 5 μm or less. .

  In the curable composition for inkjet according to the present invention, the viscosity at 25 ° C. measured in accordance with JIS K2283 is preferably 160 mPa · s or more and 500 mPa · s or less.

  Further, according to a wide aspect of the present invention, there is provided a method for producing a printed wiring board having a resist pattern, wherein an ink-jet curable composition configured according to the present invention is applied by an ink-jet method to form a pattern. A step of drawing, and a step of forming a resist pattern by applying light and applying heat to the curable composition for inkjet drawn in a pattern and curing it.

  The curable composition for inkjet according to the present invention includes a polyfunctional compound having two or more (meth) acryloyl groups, a photopolymerization initiator, a compound having a cyclic ether group, and a curing agent. It is cured by irradiation and is also cured by application of heat. Moreover, since the said hardening | curing agent is a dicyandiamide particle | grain whose median diameter is 5 micrometers or less, the curable composition for inkjet which concerns on this invention can be applied by an inkjet system.

  Furthermore, the curable composition for inkjet according to the present invention has the above-described composition, and particularly the above-mentioned curing agent is dicyandiamide particles having a median diameter of 5 μm or less. The pot life is long enough even in the environment of Moreover, since the compound which has a cyclic ether group is contained, the heat resistance of hardened | cured material is high. Moreover, since the said hardening | curing agent is a dicyandiamide particle whose median diameter is 5 micrometers or less, the insulation reliability of hardened | cured material is favorable.

  Details of the present invention will be described below.

(Curable composition for inkjet)
The curable composition for inkjet according to the present invention includes a polyfunctional compound (A) having two or more (meth) acryloyl groups, a photopolymerization initiator (B), a compound (C) having a cyclic ether group, And a curing agent (D). The curing agent (D) is dicyandiamide particles having a median diameter of 5 μm or less. The term “(meth) acryloyl group” refers to an acryloyl group and a methacryloyl group.

  Since the curable composition for inkjet according to the present invention contains the polyfunctional compound (A) and the photopolymerization initiator (B), it can be cured by light irradiation. Since the curable composition for inkjet according to the present invention contains the compound (C) having a cyclic ether group and the curing agent (D), it can be cured by application of heat. Therefore, the curable composition for inkjet according to the present invention is curable by light irradiation and application of heat, and is an inkjet light and thermosetting composition. In the curable composition for inkjet according to the present invention, a primary cured product is obtained by irradiation with light, and then subjected to main curing by applying heat to the primary cured product to obtain a resist pattern that is a cured product. In this way, by performing primary curing by light irradiation, wetting and spreading of the curable composition for inkjet coated on a coating target member such as a substrate can be suppressed. Therefore, a fine resist pattern can be formed with high accuracy.

  The curable composition for inkjet according to the present invention includes a polyfunctional compound (A) having two or more (meth) acryloyl groups, a photopolymerization initiator (B), a compound (C) having a cyclic ether group, Since the curing agent (D) is a dicyandiamide particle having a median diameter of 5 μm or less because it contains the curing agent (D), the compound (C) having a cyclic ether group and the curing agent (D) are contained. Nevertheless, the pot life can be made sufficiently long even in an environment inside the ink jet apparatus heated to 50 ° C. or higher. Moreover, even if the curable composition for inkjet before the coating by the inkjet method is heated to 50 ° C. or higher, the viscosity does not easily increase and the thermal curing does not easily proceed. For this reason, the curable composition for inkjet is excellent in stability at high temperatures, and can be stably discharged from the inkjet nozzle.

  Moreover, since the curable composition for inkjet which concerns on this invention contains the compound (C) which has a cyclic ether group especially, it can improve the heat resistance of the hardened | cured material after hardening.

  Furthermore, in the curable composition for inkjet according to the present invention, since the curing agent (D) is dicyandiamide particles having a median diameter of 5 μm or less, the insulation reliability of the cured product after curing can be improved.

  Hereinafter, the detail of each component contained in the curable composition for inkjet which concerns on this invention is demonstrated.

[Polyfunctional compound (A)]
The polyfunctional compound (A) is not particularly limited as long as it has two or more (meth) acryloyl groups. As the polyfunctional compound (A), a conventionally known polyfunctional compound having two or more (meth) acryloyl groups can be used. Since the polyfunctional compound (A) has two or more (meth) acryloyl groups, polymerization proceeds and cures upon irradiation with light. For this reason, curing can be advanced by irradiating light after coating the curable composition, the applied shape can be maintained, and primary curing of the curable composition irradiated with light. It can suppress effectively that a thing and hardened | cured material spread too much. As for a polyfunctional compound (A), only 1 type may be used and 2 or more types may be used together.

  As the polyfunctional compound (A), (meth) acrylic acid adducts of polyhydric alcohols, (meth) acrylic acid adducts of alkylene oxide modified products of polyhydric alcohols, urethane (meth) acrylates, and polyesters (meth) Examples include acrylates. Examples of the polyhydric alcohol include diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, trimethylol propane, cyclohexane dimethanol, tricyclodecane dimethanol, an alkylene oxide adduct of bisphenol A, and Examples include pentaerythritol. The term “(meth) acrylate” refers to acrylate and methacrylate. The term “(meth) acryl” refers to acrylic and methacrylic.

  The compounding quantity of a polyfunctional compound (A) is suitably adjusted so that it may harden | cure moderately by irradiation of light, and is not specifically limited. As an example of the blending amount of the polyfunctional compound (A), the content of the polyfunctional compound (A) is preferably 40% by weight or more, more preferably 60% by weight in 100% by weight of the curable composition for inkjet. Above, preferably 95% by weight or less, more preferably 90% by weight or less. In 100% by weight of the curable composition for inkjet, the upper limit of the content of the polyfunctional compound (A) is appropriately adjusted depending on the contents of the components (B) to (D) and other components.

[Photoinitiator (B)]
In order to cure the curable composition by irradiation with light, the curable composition for inkjet according to the present invention contains a photopolymerization initiator (B). Examples of the photopolymerization initiator (B) include a photoradical polymerization initiator and a photocationic polymerization initiator. The photopolymerization initiator (B) is preferably a radical photopolymerization initiator. As for a photoinitiator (B), only 1 type may be used and 2 or more types may be used together.

  The photo radical polymerization initiator is not particularly limited. The photo radical polymerization initiator is a compound for generating radicals upon light irradiation and initiating a radical polymerization reaction. Specific examples of the photo radical polymerization initiator include, for example, benzoin, benzoin alkyl ethers, acetophenones, aminoacetophenones, anthraquinones, thioxanthones, ketals, 2,4,5-triarylimidazole dimers, Examples include riboflavin tetrabutyrate, thiol compounds, 2,4,6-tris-s-triazine, organic halogen compounds, benzophenones, xanthones, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide. As for the said radical photopolymerization initiator, only 1 type may be used and 2 or more types may be used together.

  Examples of the benzoin alkyl ethers include benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether. Examples of the acetophenones include acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone and 1,1-dichloroacetophenone. Examples of the aminoacetophenones include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane. Examples include -1-one and N, N-dimethylaminoacetophene. Examples of the anthraquinones include 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone and 1-chloroanthraquinone. Examples of the thioxanthones include 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone. Examples of the ketals include acetophenone dimethyl ketal and benzyl dimethyl ketal. Examples of the thiol compound include 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, and 2-mercaptobenzothiazole. Examples of the organic halogen compound include 2,2,2-tribromoethanol and tribromomethylphenyl sulfone. Examples of the benzophenones include benzophenone and 4,4'-bisdiethylaminobenzophenone.

  A photopolymerization initiation assistant may be used together with the photo radical polymerization initiator. Examples of the photopolymerization initiation assistant include N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, and triethanolamine. Photopolymerization initiation assistants other than these may be used. As for the said photoinitiation adjuvant, only 1 type may be used and 2 or more types may be used together.

  In addition, a titanocene compound such as CGI-784 (manufactured by Ciba Specialty Chemicals) having absorption in the visible light region may be used to promote the photoreaction.

  It does not specifically limit as said photocationic polymerization initiator, For example, a sulfonium salt, an iodonium salt, a metallocene compound, a benzoin tosylate etc. are mentioned. As for the said photocationic polymerization initiator, only 1 type may be used and 2 or more types may be used together.

  The content of the photopolymerization initiator (B) with respect to 100 parts by weight of the polyfunctional compound (A) is preferably 0.1 parts by weight or more, more preferably 1 part by weight or more, and further preferably 3 parts by weight or more. The amount is preferably 30 parts by weight or less, more preferably 15 parts by weight or less, and still more preferably 10 parts by weight or less. When the content of the photopolymerization initiator (B) is not less than the above lower limit and not more than the above upper limit, the curable composition is more effectively cured by light irradiation.

[Compound having cyclic ether group (C)]
The curable composition for inkjet according to the present invention contains a compound (C) having a cyclic ether group so that it can be cured by application of heat. By using compound (C), the primary cured product can be further cured by applying heat after first curing the inkjet curable composition by light irradiation to obtain a primary cured product. For this reason, by using compound (C), a resist pattern can be formed efficiently and accurately, and the heat resistance and insulation reliability of the cured product can be further increased. Only 1 type may be used for the compound (C) which has a cyclic ether group, and 2 or more types may be used together.

  The compound (C) having a cyclic ether group is not particularly limited as long as it has a cyclic ether group. Examples of the cyclic ether group in the compound (C) include an epoxy group and an oxetanyl group. Of these, the cyclic ether group is preferably an epoxy group from the viewpoint of enhancing curability and obtaining a cured product that is more excellent in heat resistance and insulation reliability. The compound (C) having a cyclic ether group preferably has two or more cyclic ether groups.

  Specific examples of compounds having an epoxy group include heterocyclic epoxy compounds such as bisphenol S type epoxy compounds, diglycidyl phthalate compounds, triglycidyl isocyanurates, bixylenol type epoxy compounds, biphenol type epoxy compounds, tetraglycidyl xylenoyl Ethane compound, bisphenol A type epoxy compound, hydrogenated bisphenol A type epoxy compound, bisphenol F type epoxy compound, brominated bisphenol A type epoxy compound, phenol novolac type epoxy compound, cresol novolac type epoxy compound, alicyclic epoxy compound, bisphenol A novolac type epoxy compound, chelate type epoxy compound, glyoxal type epoxy compound, amino group-containing epoxy compound, rubber-modified epoxy compound , Dicyclopentadiene phenolic type epoxy compounds, silicone-modified epoxy compounds and ε- caprolactone-modified epoxy compounds and the like.

  The compound having an oxetanyl group is exemplified in, for example, Japanese Patent No. 3074086.

  The viscosity of the compound (C) having a cyclic ether group at 25 ° C. preferably exceeds 300 mPa · s.

  The compounding quantity of the compound (C) which has a cyclic ether group is suitably adjusted so that it may harden | cure moderately by provision of heat, and is not specifically limited. In 100% by weight of the curable composition for inkjet, the content of the compound (C) having a cyclic ether group is preferably 3% by weight or more and 50% by weight or less. The content of the compound (C) having a cyclic ether group in 100% by weight of the curable composition for inkjet is more preferably 5% by weight or more, further preferably 10% by weight or more, and more preferably 40% by weight or less. . When the content of the compound (C) is not less than the above lower limit, the curable composition can be more effectively cured by application of heat. When the content of the compound (C) is not more than the above upper limit, the heat resistance of the cured product is further increased.

[Curing agent (D)]
The curing agent (D) contained in the curable composition for inkjet according to the present invention is dicyandiamide particles having a median diameter of 5 μm or less. Since the curing agent (D) is used, the curable composition can be cured by applying heat. Moreover, the insulation reliability of hardened | cured material can be made high by thermosetting the curable composition which used together the compound (C) which has a cyclic ether group, and a hardening | curing agent (D).

The above dicyandiamide particles:
Since the curing agent (D) is dicyandiamide particles having a median diameter of 5 μm or less, the dicyandiamide particles are present in a solid state in the liquid component contained in the curable composition for inkjet. In the curable composition for inkjet before coating by the inkjet method, the dicyandiamide particles are present in a solid state in the liquid component. Moreover, in the curable composition for inkjet before irradiation with light and application of heat, the dicyandiamide particles are present in a solid state in the liquid component. In the ink-jet curable composition heated to 50 ° C., the dicyandiamide particles are preferably present in a solid state in the liquid component. In the curable composition for inkjet heated to 80 ° C., it is more preferable that the dicyandiamide particles are present in a solid state in the liquid component.

  Examples of the liquid component include two or more liquid (meth) acryloyl groups among the polyfunctional compound (A) having two or more (meth) acryloyl groups and the compound (C) having a cyclic ether group. And a polyfunctional compound having a liquid and a compound having a cyclic ether group that is liquid.

  The shape of the particles in the dicyandiamide particles is not particularly limited, and examples thereof include spherical shapes, polygonal shapes, and irregular shapes.

  In order to suppress clogging of the nozzles of the inkjet head and to enable stable ejection, the median diameter of the diciamine diamide particles is 5 μm or less.

  When the curable composition for inkjet is thermally cured, the dicyandiamide particles in the curable composition for inkjet are preferably not in a solid state. Considering the thermosetting temperature, the cyandiamide particles are preferably not in a solid state at a temperature exceeding 80 ° C. and not more than 250 ° C., more preferably not exceeding a solid state at a temperature exceeding 100 ° C. and not more than 250 ° C. In these cases, the dicyandiamide particles effectively act as a curing agent by heating to thermally cure the curable composition for inkjet.

  The compounding ratio of the compound (C) having a cyclic ether group and the dicyandiamide particles is not particularly limited. The blending amount of the dicyandiamide particles is appropriately adjusted so as to be appropriately cured by application of heat, and is not particularly limited. The content of the dicyandiamide particles with respect to 100 parts by weight of the compound (C) having a cyclic ether group is preferably 0 part by weight or more, more preferably 1 part by weight or more, still more preferably 3 parts by weight or more, preferably 20 It is 10 parts by weight or less, more preferably 10 parts by weight or less.

[Other ingredients]
The curable composition for inkjet according to the present invention may contain a thermosetting agent other than the dicyandiamide particles as the curing agent (D). Furthermore, the curable composition for inkjet according to the present invention may contain a curing accelerator.

  Specific examples of the thermosetting agent include organic acids, amine compounds, amide compounds, hydrazide compounds, imidazole compounds, imidazoline compounds, phenol compounds, urea compounds, polysulfide compounds, and acid anhydrides. A modified polyamine compound such as an amine-epoxy adduct may be used as the thermosetting agent.

  Examples of the curing accelerator include tertiary amines, imidazoles, quaternary ammonium salts, quaternary phosphonium salts, organometallic salts, phosphorus compounds, urea compounds, and the like.

  You may mix | blend various additives with the curable composition for inkjet which concerns on this invention in the range which does not inhibit the objective of this invention. The additive is not particularly limited, and examples thereof include a colorant, a polymerization inhibitor, an antifoaming agent, a leveling agent, and an adhesion imparting agent.

  Examples of the colorant include phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black. Examples of the polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol, pyrogallol and phenothiazine. Examples of the antifoaming agent include silicone-based antifoaming agents, fluorine-based antifoaming agents, and polymer-based antifoaming agents. Examples of the leveling agent include silicone leveling agents, fluorine leveling agents, and polymer leveling agents. Examples of the adhesion imparting agent include imidazole adhesion imparting agents, thiazole adhesion imparting agents, triazole adhesion imparting agents, and silane coupling agents.

  In the curable composition for inkjet according to the present invention, the viscosity at 25 ° C. measured in accordance with JIS K2283 is preferably 160 mPa · s or more and 500 mPa · s or less. When the viscosity of the curable composition for inkjet is not less than the above lower limit and not more than the above upper limit, the curable composition for inkjet can be easily and accurately discharged from the inkjet head.

(Printed wiring board)
Next, a method for manufacturing a printed wiring board according to the present invention will be described.

  The method for producing a printed wiring board according to the present invention is characterized by using the above-described curable composition for inkjet. That is, in the method for producing a printed wiring board according to the present invention, first, the curable composition for inkjet is applied by an inkjet method to draw a pattern. At this time, it is particularly preferable to directly draw the curable composition for inkjet. “Direct drawing” means drawing without using a mask.

  An ink jet printer is used for application of the ink jet curable composition. The ink jet printer has an ink jet head. The inkjet head has a nozzle. The ink jet device preferably includes a heating unit for heating the temperature in the ink jet device or the ink jet head to 50 ° C. or higher. It is preferable that the said inkjet curable composition is coated on the coating object member. A substrate etc. are mentioned as said coating object member. Examples of the substrate include a substrate having wirings provided on the upper surface.

  Next, the ink-jet curable composition drawn in a pattern is irradiated with light and heated to be cured to form a resist pattern. In this way, a printed wiring board having a resist pattern can be obtained. The resist pattern is preferably a solder resist pattern.

  The ink-jet curable composition drawn in a pattern may be primarily cured by irradiating light to obtain a primary cured product. Thereby, wetting and spreading of the drawn curable composition for inkjet can be suppressed, and a highly accurate resist pattern can be formed. In addition, when a primary cured product is obtained by light irradiation, the primary cured product may be subjected to main curing by applying heat to obtain a cured product to form a resist pattern. The curable composition for inkjet according to the present invention can be cured by light irradiation and heat application. When photocuring and thermosetting are used in combination, a resist pattern that is more excellent in heat resistance can be formed. The heating temperature for curing by applying heat is preferably 100 ° C. or higher, more preferably 120 ° C. or higher, preferably 250 ° C. or lower, more preferably 200 ° C. or lower.

  The light irradiation may be performed after drawing or may be performed simultaneously with drawing. For example, light may be irradiated at the same time as or after the ejection of the curable composition. Thus, in order to irradiate light simultaneously with drawing, the light source may be arranged so that the light irradiation portion is positioned at the drawing position by the inkjet head.

  The light source for irradiating light is suitably selected according to the light to irradiate. Examples of the light source include a UV-LED, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, and a metal halide lamp. The irradiated light is generally ultraviolet rays, and may be an electron beam, α-ray, β-ray, γ-ray, X-ray, neutron beam, or the like.

  The temperature at the time of application | coating of the curable composition for inkjets will not be specifically limited if it is the temperature from which the curable composition for inkjets becomes the viscosity which can be discharged from an inkjet head. The temperature at the time of application of the curable composition for inkjet is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, and preferably 100 ° C. or lower. The viscosity of the curable composition for inkjet at the time of coating is not particularly limited as long as it can be discharged from the inkjet head.

  Since the curable composition for inkjet according to the present invention contains a specific curing agent (D), for example, even when the curable composition for inkjet is heated in an inkjet head, the curable composition for inkjet is used. Pot life is sufficiently long and stable discharge is possible. Furthermore, since the inkjet curable composition can be heated to a viscosity suitable for coating by an inkjet method, a printed wiring board can be suitably produced by using the inkjet curable composition according to the present invention. .

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited only to the following examples.

Example 1
80 parts by weight of trimethylolpropane triacrylate (“TMPTA” manufactured by Daicel Cytec Co., Ltd.) corresponding to the polyfunctional compound (A) and an α-aminoacetophenone type photoradical polymerization initiator (BASF) corresponding to the photopolymerization initiator (B) “Irgacure 907” manufactured by the company, 20 parts by weight of bisphenol A type epoxy resin (“YD-127” manufactured by Nippon Steel Chemical Co., Ltd.) corresponding to the compound (C) having a cyclic ether group, and dicyandiamide particles 1 part by weight of the corresponding cyandiamide (median diameter: 3 μm, “DICY7” manufactured by Mitsubishi Chemical Corporation) was mixed to obtain a curable composition for inkjet.

(Example 2 and Comparative Examples 1 to 3)
The curable composition for inkjet was obtained like Example 1 except having changed the kind and compounding quantity of the compounding component as shown in Table 1 below.

(Evaluation)
(1) Viscosity Based on JIS K2283, the viscosity at 25 degreeC of the obtained curable composition for inkjets was measured using the viscometer ("TVE22L" by the Toki Sangyo company). The viscosity of the curable composition for inkjet was determined according to the following criteria.

[Criteria for viscosity]
○: Viscosity is 160 mPa · s or more and 500 mPa · s or less ×: Viscosity is less than 160 mPa · s or viscosity is more than 500 mPa · s

(2) Filtration characteristic It tried to filter the obtained curable composition for inkjets using a 5 micrometer membrane filter. The filtration characteristics at this time were determined according to the following criteria.

[Criteria for filtration characteristics]
○: The filter could be filtered with a 5 μm filter, and the filter was not clogged. ×: The filter could not be filtered with a 5 μm filter, or the filter was clogged.

(3) Storage stability (length of pot life)
The curable composition for inkjet filtered in the above (2) Evaluation of filtration characteristics was heated at 80 ° C. for 12 hours.

  The FR-4 board | substrate with copper foil with which copper foil was affixed on the upper surface was prepared. An ink-jet curable composition is applied on a copper foil on a substrate from an ink-jet head of a piezo-type ink-jet printer with an ultraviolet irradiation device (head temperature: 80 ° C.) so that the line width is 80 μm and the distance between the lines is 80 μm. Tried to draw on. From the ejection properties from the inkjet head at this time, the storage stability was determined according to the following criteria.

[Criteria for storage stability]
○: The composition could be ejected from the inkjet head. X: The composition was cured before ejection, or the viscosity of the composition increased, and the composition could not be ejected from the inkjet head.

(4) Heat resistance In the evaluation of heat resistance, a curable composition for inkjet that was not heated at 80 ° C. for 12 hours was used.

  The FR-4 board | substrate with copper foil with which copper foil was affixed on the upper surface was prepared. An ink-jet curable composition is applied on a copper foil on a substrate from an ink-jet head of a piezo-type ink-jet printer with an ultraviolet irradiation device (head temperature: 80 ° C.) so that the line width is 80 μm and the distance between the lines is 80 μm. Draw on.

The curable composition for inkjet (thickness 20 μm) drawn in a pattern was irradiated with ultraviolet rays having a wavelength of 365 nm so that the irradiation energy was 1000 mJ / cm ² to obtain a primary cured product. Next, the primary cured product was heated at 150 ° C. for 60 minutes to be fully cured to obtain a resist pattern as a cured product.

  The obtained laminate of the substrate and the resist pattern was heated in an oven at 270 ° C. for 5 minutes, and then the appearance of the heated resist pattern was visually inspected. Further, a cellophane tape was attached to the resist pattern after heating, and the cellophane tape was peeled off in the 90-degree direction. The heat resistance was determined by the following criteria based on the appearance inspection and the peel test.

[Criteria for heat resistance]
○: There was no change in the resist pattern before and after heating in the appearance inspection, and the resist pattern did not peel from the substrate in the peeling test. ×: There was at least one of crack, peeling, and swelling in the resist pattern in the appearance inspection. Or the resist pattern peeled off from the substrate in the peel test

(5) Insulation reliability (migration resistance)
In the evaluation of insulation reliability, a curable composition for inkjet that was not heated at 80 ° C. for 12 hours was used.

  An IPC-B-25 comb test pattern B was prepared. The comb-shaped test pattern B is heated to 80 ° C., and an ink-jet curable composition is applied to the comb-shaped test pattern B so as to cover the entire surface of the comb-shaped test pattern B (head temperature: 80 ° C.). The ink jet head was discharged and coated.

The coated curable composition for inkjet (thickness 20 μm) was irradiated with ultraviolet rays having a wavelength of 365 nm so that the irradiation energy was 1000 mJ / cm ² to obtain a primary cured product. Next, the primary cured product was heated at 150 ° C. for 60 minutes to be fully cured to form a resist pattern as a cured product, thereby obtaining a test piece.

  The obtained test piece was subjected to a humidification test for 500 hours under the conditions of applying 85 ° C., 85% relative humidity and 50V direct current. The insulation resistance after the humidification test was measured.

  The results are shown in Table 1 below. In Table 1 below, “−” indicates that evaluation is not performed.

Claims (3)

A curable composition for inkjet that is applied by an inkjet method and is cured by irradiation with light and application of heat,
A polyfunctional compound having two or more (meth) acryloyl groups;
A photopolymerization initiator;
A compound having a cyclic ether group;
A curing agent,
A curable composition for inkjet, wherein the curing agent is dicyandiamide particles having a median diameter of 5 μm or less.   The curable composition for inkjet according to claim 1, wherein the viscosity at 25 ° C measured in accordance with JIS K2283 is 160 mPa · s or more and 500 mPa · s or less. A method for producing a printed wiring board having a resist pattern,
Applying the curable composition for inkjet according to claim 1 or 2 by an inkjet method, and drawing in a pattern;
A process for producing a printed wiring board, comprising: applying a light and applying heat to the curable composition for inkjet drawn in a pattern and curing the composition to form a resist pattern.