JP6944012B2 - Curable resin composition for inkjet - Google Patents

Description

The present invention relates to a curable resin composition for inkjet that can be applied onto a substrate such as a printed wiring board by using an inkjet method.

Conventionally, in forming an insulating coating having a desired circuit pattern on a substrate (for example, a printed wiring board), a photosensitive resin composition is applied by using a screen printing method or the like, and then pre-dried, except for a land of the circuit pattern. The non-exposed area corresponding to the land is removed with a dilute alkaline aqueous solution by adhering it on a photosensitive resin composition coated with a negative film having a translucent pattern and irradiating it with active energy rays such as ultraviolet rays. Then, the coating film was developed and post-cured.

However, the method for forming the insulating film involves many processing steps such as development, and the work is complicated. Therefore, in recent years, a resin composition is ejected onto a substrate using an inkjet method to form a coating film having a desired circuit pattern, and the coating film is exposed to active energy rays such as laser and ultraviolet rays. It is also practiced to form an insulating coating with the desired circuit pattern.

Examples of the curable resin composition used in the inkjet method suitable for producing a printed wiring board include a bisallyl nadiimide compound having a predetermined chemical structure, a bismaleimide compound having a predetermined chemical structure, a diluent, and the like. A curable resin composition for inkjet having a viscosity of 150 mPa · s or less at 25 ° C. has been proposed (Patent Document 1).

However, in the conventional curable resin composition for inkjet such as the curable resin composition used in the inkjet method of Patent Document 1, the conductor such as the copper foil of the printed wiring board is oxidized by the influence of the curable resin composition for inkjet. There is a problem that the color may be discolored, that is, the conductor such as copper foil may be deteriorated. Further, in the conventional curable resin composition for inkjet, there is room for improvement in chemical resistance such as acid resistance, heat resistance, and coating film hardness of the cured product.

International Publication No. 2006/076554

In view of the above circumstances, an object of the present invention is to prevent oxidation of a conductor such as a copper foil without impairing the coatability for inkjet, and to obtain a cured product having excellent chemical resistance, heat resistance, and coating hardness. It is to provide a curable resin composition for inkjet which can be obtained.

Aspects of the present invention include (A) a (meth) acrylate compound having a weight average molecular weight of 500 or more, (B) a (meth) acrylate compound having a weight average molecular weight of less than 500, and (C) a photopolymerization initiator. D) A curable resin composition for inkjet containing a compound having a primary amino group and an imino group, wherein the curable resin composition has a viscosity at 25 ° C. of 200 mPa · s or less. It is a composition.

Aspect of the present invention is the curable resin composition for inkjet, wherein the (A) (meth) acrylate compound having a weight average molecular weight of 500 or more has two or more imide rings in one molecule. ..

［式（ｉ）中、Ｒ^０は、−ＣＨ_２−又は−ＣＨ_２Ｏ−Ｒ^０１−を表し、Ｒ^１は、メチル基又は水素を意味し、点線は二重結合であってもよい結合箇所を示し、Ｇは、下記一般式（ｉａ）、（ｉｂ）又は（ｉｃ）で表される、２価又は３価の基を表し、ｍはＧの価数に対応する数であり、Ｒ^０１は、炭素数２〜１０の分岐又は直鎖状アルキレン基を表す。

（式（ｉａ）中、Ｒ^２〜Ｒ^４は、それぞれ独立して、水素原子又はメチル基を表す。）

（式（ｉｂ）中、Ｒ^５及びＲ^６は、それぞれ独立して、水素原子又はメチル基を意味する。）

（式（ｉｃ）中、ｐは２〜５の整数を意味する。）］
で表される化合物である、インクジェット用硬化性樹脂組成物である。 In the embodiment of the present invention, the (meth) acrylate compound having the weight average molecular weight of (A) of 500 or more is the following general formula (i).

[In formula (i), R ⁰ represents −CH ₂ − or −CH ₂ ^{OR 01} −, R ¹ means a methyl group or hydrogen, and the dotted line may be a double bond. A place is shown, G represents a divalent or trivalent group represented by the following general formula (ia), (ib) or (ic), m is a number corresponding to the valence of G, and R ⁰¹ represents a branched or linear alkylene group having 2 to 10 carbon atoms.

(In the formula ^(ia), R 2 to R ⁴ each independently represent a hydrogen atom or a methyl group.)

(In formula (ib), R ⁵ and R ⁶ independently mean a hydrogen atom or a methyl group.)

(In the formula (ic), p means an integer of 2 to 5.)]
A curable resin composition for inkjet, which is a compound represented by.

An aspect of the present invention is the curable resin composition for inkjet in which the (A) (meth) acrylate compound having a weight average molecular weight of 500 or more is 500 or more and 5000 or less in weight average molecular weight.

（式（ｉｉ）中、Ｒ^７及びＲ^８は、それぞれ独立して、ハロゲン、ＯＨ、Ｈ、炭素数１〜３のアルキル基を意味する。）で表されるジシアンジアミド誘導体であるインクジェット用硬化性樹脂組成物である。 In the embodiment of the present invention, the compound having the primary amino group and the imino group (D) is dicyandiamide or the following general formula (ii).

(In the formula (ii), R ⁷ and R ⁸ independently mean halogen, OH, H, and an alkyl group having 1 to 3 carbon atoms), which is a dicyandiamide derivative and has curability for inkjet. It is a resin composition.

An aspect of the present invention is an inkjet curable resin composition in which the (B) (meth) acrylate compound having a weight average molecular weight of less than 500 is a polyfunctional (meth) acrylate compound.

Aspect of the present invention is a cured product of the curable resin composition for inkjet. Examples of the cured product include a photocurable film of a curable resin composition for inkjet.

An aspect of the present invention is a printed wiring board provided with the cured product. Examples of the printed wiring board include a printed wiring board provided with a photocurable film of a curable resin composition for inkjet.

According to an aspect of the present invention, a (meth) acrylate compound containing (A) a (meth) acrylate compound having a weight average molecular weight of 500 or more and (B) a (meth) acrylate compound having a weight average molecular weight of less than 500 can be added to the (meth) acrylate compound. D) By blending a compound having a primary amino group and an imino group, it is possible to prevent oxidation of a conductor such as a copper foil and obtain a cured product having excellent chemical resistance, heat resistance and coating hardness. .. Further, since the viscosity of the curable resin composition at 25 ° C. is 200 mPa · s or less, excellent coatability can be exhibited even when coated by inkjet.

According to the aspect of the present invention, (A) a (meth) acrylate compound having a weight average molecular weight of 500 or more has a chemical structure having two or more imide rings in one molecule, so that a conductor such as a copper foil can be formed. Not only the antioxidant properties are further improved, but also the coating film hardness is further improved.

According to the aspect of the present invention, (A) the (meth) acrylate compound having a weight average molecular weight of 500 or more is a compound represented by the above general formula (i), and thus the antioxidant property of a conductor such as copper foil. And the coating film hardness is also improved more reliably.

According to the aspect of the present invention, (D) the compound having a primary amino group and an imino group is a dicyandiamide or a compound represented by the above general formula (ii), whereby the oxidation of a conductor such as a copper foil is further improved. It can be reliably prevented, and a cured product having excellent chemical resistance, heat resistance, and coating hardness can be obtained more reliably.

According to the aspect of the present invention, the coating film hardness is further improved by (B) the (meth) acrylate compound having a weight average molecular weight of less than 500 being a polyfunctional (meth) acrylate compound.

Next, the curable resin composition for inkjet of the present invention will be described below. The curable resin composition for inkjet of the present invention comprises (A) a (meth) acrylate compound having a weight average molecular weight of 500 or more, (B) a (meth) acrylate compound having a weight average molecular weight of less than 500, and (C) light. It contains a polymerization initiator and (D) a compound having a primary amino group and an imino group, and has a viscosity at 25 ° C. of 200 mPa · s or less.

(A) (Meta) acrylate compound having a weight average molecular weight of 500 or more (A) (Meta) acrylate compound having a weight average molecular weight (Mw) of 500 or more (hereinafter, may be referred to as "(meth) acrylate compound (A)". ) Is not particularly limited as long as it is a (meth) acrylate compound having a weight average molecular weight of 500 or more, but for example, not only the antioxidant properties of a conductor such as copper foil are further improved, but also the coating hardness is further improved. From this point of view, the (meth) acrylate compound (A) having two or more imide rings in one molecule is preferable.

［式（ｉ）中、Ｒ^０は、−ＣＨ_２−又は−ＣＨ_２Ｏ−Ｒ^０１−を表し、Ｒ^１は、メチル基又は水素を意味し、点線は二重結合であってもよい結合箇所を示し（点線の結合箇所が二重結合である場合には、３箇所すべてが二重結合であることが好ましい。）、Ｇは、下記一般式（ｉａ）、（ｉｂ）又は（ｉｃ）で表される、２価又は３価の基を表し、ｍはＧの価数に対応する数であり、Ｒ^０１は、炭素数２〜１０の分岐又は直鎖状アルキレン基を表す。

（式（ｉａ）中、Ｒ^２〜Ｒ^４は、それぞれ独立して、水素原子又はメチル基を表す。）

（式（ｉｂ）中、Ｒ^５及びＲ^６は、それぞれ独立して、水素原子又はメチル基を意味する。）

（式（ｉｃ）中、ｐは２〜５の整数を意味する。）］で表される（メタ）アクリレート化合物（Ａ）が好ましい。なお、上記一般式（ｉａ）〜（ｉｃ）において、波線と交差した結合は、一般式（ｉ）におけるＧとＮ原子との間の結合を示す。一般式（ｉ）のＮ原子は、酸素原子又はカルボニル基のオルト位、メタ位又はパラ位のいずれでもよいが、パラ位が好ましい。上記から、一般式（ｉ）で表される（メタ）アクリレート化合物（Ａ）は、遊離のカルボキシル基を有していない。 Examples of the (meth) acrylate compound (A) having two or more imide rings in one molecule include the general formula (i).

[In formula (i), R ⁰ represents −CH ₂ − or −CH ₂ ^{OR 01} −, R ¹ means a methyl group or hydrogen, and the dotted line may be a double bond. Indicates a location (when the dotted connection location is a double bond, it is preferable that all three locations are double bonds), and G is the following general formula (ia), (ib) or (ic). Represents a divalent or trivalent group represented by, m is a number corresponding to the valence of G, and R ⁰¹ represents a branched or linear alkylene group having 2 to 10 carbon atoms.

(In the formula ^(ia), R 2 to R ⁴ each independently represent a hydrogen atom or a methyl group.)

(In formula (ib), R ⁵ and R ⁶ independently mean a hydrogen atom or a methyl group.)

(In the formula (ic), p means an integer of 2 to 5)], the (meth) acrylate compound (A) is preferable. In the general formulas (ia) to (ic), the bond intersecting the wavy line indicates the bond between the G and N atoms in the general formula (i). The N atom of the general formula (i) may be any of the ortho-position, meta-position or para-position of the oxygen atom or the carbonyl group, but the para-position is preferable. From the above, the (meth) acrylate compound (A) represented by the general formula (i) does not have a free carboxyl group.

Further, examples of the (meth) acrylate compound (A) other than the (meth) acrylate compound having two or more imide rings in one molecule include epoxy (meth) acrylate. Epoxy (meth) acrylate can be obtained by reacting (meth) acrylic acid with at least a part of the epoxy groups of an epoxy resin having one or more epoxy groups in one molecule.

Examples of the epoxy resin include rubber-modified epoxy resins such as biphenyl aralkyl type epoxy resin, phenyl aralkyl type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, and silicone-modified epoxy resin, and ε-caprolactone. Modified epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, cyclic aliphatic polyfunctional epoxy resin, glycidyl ester type polyfunctional epoxy resin, glycidylamine type polyfunctional epoxy Examples thereof include a resin, a heterocyclic polyfunctional epoxy resin, a bisphenol-modified novolak type epoxy resin, and a polyfunctional modified novolac type epoxy resin. From the above, the (meth) acrylate compound (A), which is an epoxy (meth) acrylate, does not have a free carboxyl group.

Examples of the (meth) acrylate compound (A) other than the (meth) acrylate compound having two or more imide rings in one molecule and the epoxy (meth) acrylate include urethane (meth) acrylate. The urethane (meth) acrylate may be any urethane (meth) acrylate obtained by reacting urethane with (meth) acrylic acid, and is not limited to a specific compound. Urethane is a resin obtained by reacting a compound having two or more isocyanate groups in one molecule with a polyol compound having two or more hydroxyl groups in one molecule.

The compound having two or more isocyanate groups in one molecule is not particularly limited, and for example, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), methylene diisocyanate (MDI), methylenebiscyclohexylisocyanate, and the like. Examples thereof include trimethylhexamethyldiisocyanate, hexanediisocyanate, hexamethylaminediisocyanate, methylenebiscyclohexylisocyanate, toluenediisocyanate, 1,2-diphenylethanediisocyanate, 1,3-diphenylpropanediisocyanate, diphenylmethanediisocyanate, and dicyclohexylmethyldiisocyanate. These compounds may be used alone or in combination of two or more.

The polyol compound having two or more hydroxyl groups in one molecule is not particularly limited, and is, for example, ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2. -Butylene glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, neopentyl glycol, 1,6-hexanediol, 2,2- Diethyl-1,3-propanediol, 3,3-dimethylolheptan, 2-ethyl-2-butyl-1,3-propanediol, 1,12-dodecanediol, 1,18-octadecandiol, etc. have 2 carbon atoms. Hydroxyl diols such as alkanediol, 2-butene-1,4-diol, 2,6-dimethyl-1-octene-3,8-diol and the like; 1,4-cyclohexanediol, 1, Alicyclic diols such as 4-cyclohexanedimethanol; glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,6-hexanetriol , Trimethylol ethane, trimethyl propane, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3- (hydroxymethyl) pentane, 2,2-bis (hydroxymethyl) -3 -Adiol triols such as butanol; polyols having four or more hydroxyl groups such as tetramethylolmethane, pentaerythritol, dipentaerythritol and xylitol can be mentioned. These compounds may be used alone or in combination of two or more. From the above, the (meth) acrylate compound (A), which is a urethane (meth) acrylate, does not have a free carboxyl group.

The (meth) acrylate compound, epoxy (meth) acrylate, and urethane (meth) acrylate having two or more imide rings in one molecule described above may be used alone or in combination of two or more. ..

The weight average molecular weight of the (meth) acrylate compound (A) is not particularly limited as long as it is 500 or more, but is preferably 1000 or more from the viewpoint of further improving the heat resistance of the cured product of the curable resin composition for inkjet. The above is particularly preferable. On the other hand, the upper limit of the weight average molecular weight of the (meth) acrylate compound (A) is not particularly limited, but 5000 is preferable and 4000 is particularly preferable from the viewpoint of surely preventing an increase in viscosity.

(B) (Meta) acrylate compound having a weight average molecular weight of less than 500 (B) (Meta) acrylate compound having a weight average molecular weight (Mw) of less than 500 (hereinafter, may be referred to as "(meth) acrylate compound (B)". ) Is not particularly limited as long as it is a (meth) acrylate compound having a weight average molecular weight of less than 500, and examples thereof include a monofunctional (meth) acrylate compound and a bifunctional or higher (meth) acrylate compound. .. By blending the (meth) acrylate compound (B), the viscosity of the curable resin composition at 25 ° C. can be easily adjusted to 200 mPa · s or less. Therefore, it can be used for inkjet without adding a non-reactive diluent (for example, an organic solvent) described later.

Examples of the (meth) acrylate compound (B) include benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, phenol (meth) acrylate, phenoxyethyl (meth) acrylate, and diethylene glucol mono. Monofunctional (meth) acrylate compounds such as (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylicate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) Acrylate, neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, ethylene oxide-modified diphosphate Bifunctional (meth) acrylate compounds such as (meth) acrylate, cyclohexylated cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethyl propantri (meth) acrylate, ditrimethylolpropantetra (meth) acrylate, di Examples thereof include trifunctional or higher functional (meth) acrylate compounds such as pentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. These may be used alone or in combination of two or more.

Of these, a bifunctional or higher functional (meth) acrylate compound is preferable from the viewpoint of further improving the coating film hardness of the cured product of the curable resin composition for inkjet.

The content of the (meth) acrylate compound (B) is not particularly limited, but is preferably 100 parts by mass to 600 parts by mass with respect to 100 parts by mass (solid content, the same applies hereinafter) of the (meth) acrylate compound (A). 200 parts by mass to 500 parts by mass is more preferable, and 250 parts by mass to 350 parts by mass is particularly preferable.

(C) Photopolymerization Initiator The (C) photopolymerization initiator is not particularly limited, and known photopolymerization initiators can be used. Examples of the photopolymerization initiator include bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether. Benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-methyl-4'-(methylthio) -2 -Morphorinopropiophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1- On, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p. -Phenylbenzophenone, 4,4'-bis (diethylamino) benzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiary butyl anthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone. , 2-Chlorthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, P-dimethylaminobenzoic acid ethyl ester and the like. These may be used alone or in combination of two or more.

The content of the photopolymerization initiator is not particularly limited, but is preferably 10 parts by mass to 100 parts by mass, and particularly preferably 30 parts by mass to 70 parts by mass with respect to 100 parts by mass of the (meth) acrylate compound (A).

(D) Compound having primary amino group and imino group (D) Compound having primary amino group and imino group prevents oxidation of conductors such as copper foil, and has chemical resistance and heat resistance. , Contributes to obtaining a cured product having excellent coating hardness. The compound having a primary amino group and an imino group is not particularly limited as long as it is a compound having a structure having a primary amino group and an imino group in one molecule, but it more reliably prevents oxidation of a conductor such as a copper foil. However, dicyandiamide and dicyanamide derivatives are preferable from the viewpoint of more reliably obtaining a cured product having excellent chemical resistance, heat resistance, and coating film hardness.

（式（ｉｉ）中、Ｒ^７及びＲ^８は、それぞれ独立して、ハロゲン、ＯＨ、Ｈ、炭素数１〜３のアルキル基を意味する。）で表される化合物を挙げることができる。 The dicyanamide derivative is, for example, a compound portion synthesized from dicyandiamide and an aromatic amine, and the dicyanamide derivative is described in the following general formula (ii).

(In the formula (ii), R ⁷ and R ⁸ independently mean halogen, OH, H, and an alkyl group having 1 to 3 carbon atoms).

The content of the compound having a primary amino group and an imino group is not particularly limited, but the lower limit thereof is (meth) from the viewpoint of surely obtaining the antioxidant property, chemical resistance, heat resistance and coating hardness of the conductor. ) The acrylate compound (A) is preferably 0.10 parts by mass, more preferably 0.20 parts by mass, and particularly preferably 0.30 parts by mass with respect to 100 parts by mass. On the other hand, the upper limit of the content of the compound having a primary amino group and an imino group is 5 with respect to 100 parts by mass of the (meth) acrylate compound (A) from the viewpoint of preventing a decrease in the toughness of the cured coating film. .0 parts by mass is preferable, 2.0 parts by mass is more preferable, and 1.0 part by mass is particularly preferable.

The viscosity of the curable resin composition for inkjet of the present invention at 25 ° C. is 200 mPa · s or less. By having the above viscosity range at 25 ° C., the curable resin composition can be smoothly applied onto the substrate by the inkjet method. The viscosity of the curable resin composition for inkjet at 25 ° C. is not particularly limited as long as it is 200 mPa · s or less, but 100 mPa · s or less is preferable, and 50 mPa · s or less is particularly preferable. The range of the viscosity at 25 ° C. can be adjusted by appropriately adding not only the (meth) acrylate compound (B) but also a non-reactive diluent (for example, an organic solvent) described later.

The lower limit of the viscosity of the curable resin composition for inkjet at 25 ° C. is not particularly limited, but is preferably 10 mPa · s from the viewpoint of maintaining the shape of the coating film, for example.

In the curable resin composition for inkjet of the present invention, in addition to the above components (A) to (D), other components such as colorants, various additives, non-reactive diluents and the like are required. Can be blended.

The colorant is not particularly limited to pigments, pigments and the like, and any color such as a white colorant, a blue colorant, a green colorant, a yellow colorant, a purple colorant, a black colorant and the like can be used. Examples of the colorant include inorganic colorants such as titanium oxide which is a white colorant and carbon black which is a black colorant, phthalocyanine green which is a green colorant, and phthalocyanine blue and lyonol blue which are blue colorants. Examples thereof include phthalocyanine-based colorants such as phthalocyanine-based, chromophthal-based colorants such as chromophthal-yellow which is a yellow colorant, and organic-based colorants such as anthraquinone-based.

Various additives include, for example, antifoaming agents such as silicone-based, hydrocarbon-based and acrylic-based, extender pigments such as talc, barium sulfate, alumina, aluminum hydroxide, mica and silica, powdered urethane resin, and (meth) acrylic. Examples thereof include polymers, vinyl-based polymers, modified carboxyl group-containing polymers, organic fillers such as carboxylic acid esters, and flame retardants.

The non-reactive diluent is for adjusting the viscosity and drying property of the curable resin composition for inkjet. Examples of the non-reactive diluent include organic solvents. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexane, aromatic hydrocarbons such as toluene and xylene, alcohols such as methanol, isopropanol and cyclohexanol, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane. Cellosolves such as cellosolve and butylcellosolve, carbitols such as carbitol and butylcarbitol, ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether Examples thereof include esters such as acetate.

The method for producing the curable resin composition for inkjet of the present invention is not limited to a specific method. It can be produced by kneading or mixing by a kneading means or a stirring means such as a super mixer or a planetary mixer. Further, before the kneading or mixing, pre-kneading or pre-mixing may be performed, if necessary.

Next, an example of how to use the curable resin composition for inkjet of the present invention will be described. The curable resin composition for inkjet of the present invention can be used, for example, to form an insulating coating (for example, a solder resist film) on a substrate (for example, a printed wiring board having a predetermined circuit pattern). First, the curable resin composition for inkjet of the present invention is coated on a printed wiring board in a desired pattern by an inkjet method (for example, an inkjet method using a jet dispenser). After coating, the coated coating film is photocured by laser direct drawing using LDI (Laser Direct Imaging) or by active energy rays such as ultraviolet rays. When the photohardening treatment is performed with active energy rays such as ultraviolet rays, the irradiation light amount is, for example, 100 to 2000 mJ / cm ² . After the photocuring treatment of the coating film, a solder resist film having a desired pattern can be formed on the printed wiring board by performing post-cure for 20 to 80 minutes in a hot air circulation type dryer or the like at 130 to 170 ° C. ..

Next, examples of the present invention will be described, but the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

Examples 1-27, Comparative Examples 1-5
Each component shown in Tables 1 to 3 below is blended in the blending ratio shown in Tables 1 to 3 below, mixed and dispersed at room temperature using a bead mill, and used in Examples 1 to 27 and Comparative Examples 1 to 5. A curable resin composition for inkjet was prepared. Unless otherwise specified, the blending amount of each component shown in Tables 1 to 3 below is shown in parts by mass. In addition, the blank part of the blending amount in Tables 1 to 3 below means no blending.

The details of each component in Tables 1 to 3 are as follows.
(A) (Meta) acrylate compound / A1 compound having a weight average molecular weight of 500 or more: A compound of the general formula (i), in which G corresponds to the general formula (ia). In the general formula (i), R ⁰ is −CH _2- , R ¹ is a methyl group, all three dotted lines are single bonds, and m is 3. In the general formula ^(ia), R 2 ~R ⁴ are both methyl groups.
-A2 compound: A compound of the general formula (i) in which G corresponds to the general formula (ib). In the general formula (i), R ⁰ is −CH _2- , R ¹ is a methyl group, all three dotted lines are single bonds, and m is 2. In the general formula (ib), R ^{5 to} R ⁶ are all methyl groups.
-A3 compound: A compound of the general formula (i) in which G corresponds to the general formula (ic). In the general formula (i), ^{R 0} is ^{_{-CH 2 O-R 01 -,}} R 1 is hydrogen, the dotted line represents a single bond all portions 3, m is ^{2, R 01} is _-C 4 _{H 8} - a. In the general formula (ic), p is 3.

The above A1 compound, A2 compound, and A3 compound were all prepared according to the method described in Examples of International Publication No. 2011/065228. The weight average molecular weights in Tables 1 to 3 were measured by GPC using THF as a mobile phase in terms of polystyrene (device name: HLC-9120 (Tosoh Corporation), column: TSKgelSuperHZM-N, speed: 0). .5 mL / min, solute concentration: 10 g / l, temperature: 40 ° C., detector: RI).

(B) (Meta) acrylate compound with a weight average molecular weight of less than 500 ・ Light ester 2EG, light ester 3EG, light ester 1.4BG: Kyoeisha Chemical Co., Ltd.
・ Aronix M-220: Toagosei Co., Ltd.
・ HDDA: Daicel Cytec Co., Ltd.
・ Piscote # 160, Piscote # 150, IBXA: Osaka Organic Chemistry Co., Ltd.
・ Miramer M140: Miwon

(C) Photopolymerization Initiator-IRGACURE907, IRGACURE369E, LUCIRIN TPO, IRGACURE819: BASF Corporation
・ EAB-F: Hodogaya Chemical Co., Ltd.

(D) Compound having primary amino group and imino group ・ DICY-7: Mitsubishi Chemical Corporation
・ Phenyl pygamide: Tokyo Kasei Co., Ltd.

Melamine: Nissan Chemical Industries, Ltd.
Colorant Lionol Blue FG-7351: Toyo Color Co., Ltd.
・ Chromophthal Yellow AGR: Ciba Specialty Chemicals Co., Ltd.
Various additives ・ Fullerene G-700: Kyoeisha Chemical Co., Ltd.
・ UVX-189: Kusumoto Kasei Co., Ltd.
・ BYK-361N, BYK-168: Big Chemie Japan Co., Ltd.
Non-reactive diluent / EDGAC: Shinko Organic Chemical Industry Co., Ltd.

Specimen manufacturing process Substrate: Copper-clad laminate (thickness 1.6 mm)
Surface treatment: Buff scrub polishing Printing method: Inkjet printing (inkjet device "MJP2013F1-DU")
DRY film thickness: 20-23 μm
^{Exposure: 1000mJ / cm 2} on the coating film, Eye Graphics Co., Ltd. "UB093-5AM"
Post-cure: BOX type drying oven 150 ° C, 60 minutes

Evaluation items (1) Viscosity (mPa · s)
At 25 ° C., the curable resin composition for inkjet was measured by TVB-15M (Toki Sangyo Co., Ltd.).

(2) Copper Foil Oxidation The color tone of the copper foil portion of the test piece prepared in the above test piece manufacturing step was visually confirmed and evaluated in the following three stages.
◎: Almost no discoloration is observed before and after post-cure ○: There is a slight change before and after post-cure ×: Significant change is observed before and after post-cure

(3) Acid resistance The test piece prepared in the above test piece preparation step is immersed in a 10% by mass hydrochloric acid solution (25 ° C.) for 10 minutes, and then a tape peel test is performed on the coating film to peel off the coating film. The presence or absence was confirmed with a magnifying glass (30 times).

(4) Coating property A 100 × 100 dot pattern was applied with the above inkjet device, and then the substrate was observed with a magnifying glass (30 times) to confirm whether or not the same coating as the pattern was applied.

(5) Heat resistance After applying flux RM-26 to the test piece prepared in the above test piece preparation step, the test piece was immersed in a solder bath at 260 ° C. for 10 seconds, and the test piece was washed with isopropyl alcohol. Then, a tape peel test was performed on the coating film, and the presence or absence of peeling of the coating film was confirmed with a magnifying glass (30 times).

(6) Coating film hardness With respect to the test piece prepared in the above test piece manufacturing step, the pencil hardness of the cured coating film on the copper foil was evaluated according to the test method of JIS K-5600-5-4. The evaluation result "2H or more" was accepted.

The evaluation results are shown in Tables 1, 2 and 3 below.

As shown in Tables 1 and 2 above, (A) a (meth) acrylate compound having a weight average molecular weight of 500 or more, (B) a (meth) acrylate compound having a weight average molecular weight of less than 500, and (C) initiation of photopolymerization. In Examples 1 to 27, which are curable resin compositions for inkjet containing an agent and (D) a compound having a primary amino group and an imino group, copper foil oxidation is prevented and acid resistance (chemical resistance) is obtained. A cured product having excellent heat resistance and coating hardness could be obtained. Further, in Examples 1 to 27 having a viscosity at 25 ° C. of 35 mPa · s or less, excellent coatability for inkjet was obtained.

In particular, as shown in Table 1 above, Examples using (A) a (meth) acrylate compound having two or three imide rings in one molecule as a (meth) acrylate compound having a weight average molecular weight of 500 or more are used. Nos. 1 to 3 only further improve the copper foil antioxidant properties as compared with Examples 4 to 9 in which epoxy acrylate or urethane acrylate is used as the (meth) acrylate compound having (A) a weight average molecular weight of 500 or more. However, the hardness of the coating film was further improved. Further, as shown in Table 2 above, in Examples 10 to 13 in which the bifunctional (meth) acrylate compound was used as the (meth) acrylate compound having a weight average molecular weight of less than 500, (B) weight average was obtained. As compared with Examples 14 to 17 in which a monofunctional (meth) acrylate compound was used as the (meth) acrylate compound having a molecular weight of less than 500, the coating film hardness tended to be further improved.

On the other hand, as shown in Table 3 above, in Comparative Example 1 in which the compound (D) having a primary amino group and an imino group was not blended, the copper foil antioxidant property and acid resistance were not obtained.

(A) In Comparative Example 2 in which the (meth) acrylate compound having a weight average molecular weight of 500 or more was not blended, heat resistance and coating film hardness could not be obtained.

(B) In Comparative Example 3 in which the (meth) acrylate compound having a weight average molecular weight of less than 500 was not blended, the viscosity increased to more than 200 mPa · s, the ink could not be smoothly ejected from the inkjet device, and the coatability was obtained. I couldn't.

(C) In Comparative Example 4 in which the photopolymerization initiator was not blended, the copper foil antioxidant characteristics, acid resistance and heat resistance could not be obtained.

(D) In Comparative Example 5 in which melamine (a compound having a primary amino group but no imino group) was used instead of the compound having a primary amino group and an imino group, copper foil antioxidant properties and acid resistance were used. Was not obtained.

The curable resin composition for inkjet of the present invention prevents oxidation of conductors such as copper foil without impairing the coatability for inkjet, and is a cured product having excellent chemical resistance, heat resistance, and coating hardness. Therefore, for example, it is highly useful in the field of forming an insulating coating on a printed wiring board having a desired circuit pattern.

Claims (7)

(A) a (meth) acrylate compound having a weight average molecular weight of 500 or more, (B) a (meth) acrylate compound having a weight average molecular weight of less than 500, (C) a photopolymerization initiator, and (D) a primary amino group. A curable resin composition for inkjet, which comprises a compound having an imino group and
The (meth) acrylate compound having a weight average molecular weight of 500 or more is bifunctional to tetrafunctional.
The (A) (meth) acrylate compound having a weight average molecular weight of 500 or more has two or more imide rings in one molecule.
0.10 parts by mass or more and 2.0 parts by mass of the compound having (D) primary amino group and imino group with respect to 100 parts by mass of the (meth) acrylate compound having (A) weight average molecular weight of 500 or more. Including the following
A curable resin composition for inkjet, wherein the viscosity of the curable resin composition at 25 ° C. is 200 mPa · s or less. The (meth) acrylate compound having the weight average molecular weight of (A) of 500 or more is the following general formula (i).

[In formula (i), R ⁰ represents −CH ₂ − or −CH ₂ ^{OR 01} −, R ¹ means a methyl group or hydrogen, and the dotted line may be a double bond. A place is shown, G represents a divalent or trivalent group represented by the following general formula (ia), (ib) or (ic), m is a number corresponding to the valence of G, and R ⁰¹ represents a branched or linear alkylene group having 2 to 10 carbon atoms.

(In the formula ^(ia), R 2 to R ⁴ each independently represent a hydrogen atom or a methyl group.)

(In formula (ib), R ⁵ and R ⁶ independently mean a hydrogen atom or a methyl group.)

(In the formula (ic), p means an integer of 2 to 5.)]
In a compound represented by inkjet curable resin composition according to claim 1. The curable resin composition for inkjet according to claim 1 or 2 , wherein the (meth) acrylate compound having a weight average molecular weight of 500 or more is a weight average molecular weight of 500 or more and 5000 or less. The compound having the primary amino group and the imino group (D) is dicyandiamide or the following general formula (ii).

(In the formula (ii), R ⁷ and R ⁸ independently mean halogen, OH, H, and an alkyl group having 1 to 3 carbon atoms), which are dicyandiamide derivatives according to claims 1 to 1. 3. The curable resin composition for inkjet according to any one of 3. The curable resin composition for inkjet according to any one of claims 1 to 4 , wherein the (meta) acrylate compound having a weight average molecular weight of less than 500 is a polyfunctional (meth) acrylate compound. A cured product of the curable resin composition for inkjet according to any one of claims 1 to 5. A printed wiring board provided with the cured product according to claim 6.