JP2894167B2 - Ink composition for photocurable liquid solder resist - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable ink composition for a liquid solder resist capable of forming a permanent protective coating having excellent adhesion, heat resistance, chemical resistance and resolution on a printed wiring board. It is about its use.

[0002]

2. Description of the Related Art Until recently, a method of forming a pattern of a heat-curable or ultraviolet-curable solder resist by screen printing has been mainly employed. However, screen printing has a limitation in forming a fine pattern. It has become difficult to apply this technology to high integration in VLSI. Therefore, as the density and miniaturization of printed circuit boards have increased, the resist forming method has shifted to a solder resist using a photo printing method. At first, a dry film type was used as an application of the photographic method.However, there are problems such as the generation of air bubbles when pressed onto the substrate, and liquid solder resist, which is not limited by the coating method, is now in the spotlight. I'm taking a bath.

In a method of forming a pattern using a photographic liquid solder resist, a resist is first applied on a printed wiring board, and then heated and dried to form a coating film. A pattern film is pressed on the coating film and exposed. Finally, a series of steps of developing is performed. If adhesiveness remains in the coating film after heating and drying, the pattern film cannot be peeled off, or even if it can be peeled off, part of the resist adheres to the pattern film and the correct pattern cannot be reproduced. was there. Therefore, the tack-free property after drying in the pattern forming step is an important required performance.

[0004] Along with the tack-free property, the most strongly required performance of the liquid solder resist ink is the solder heat resistance, chemical resistance, adhesion and resolution of the coating film. In order to improve these performances, it is necessary to increase the crosslink density of the solder resist after photo-curing. Therefore, the photosensitivity of the oligomer before photopolymerization (sometimes referred to as a photopolymerizable resin) must be increased. But,
Simply increasing the number of photopolymerizable double bonds, such as by blending a low molecular weight polyfunctional photopolymerizable crosslinking agent, results in a brittle resist ink coating after photocuring and poor adhesion. This also reduced the tack-free property. For this reason, it is necessary to design a polymer molecule by first increasing the molecular weight of the photopolymerizable resin and then introducing as many photopolymerizable double bonds as possible according to the molecular weight.

When the above molecular design is actually performed, in the case of epoxy acrylate, a photopolymerizable double bond can be introduced by utilizing the reaction of an epoxy group. Even when a novolak-type epoxy resin larger than the above was used, the number of photopolymerizable double bonds that could be introduced into one molecule was about 10, and both the molecular weight and the number of double bonds were insufficient.

[0006]

SUMMARY OF THE INVENTION In view of the above circumstances, the present inventors produce a photopolymerizable resin having a sufficient molecular weight and a photopolymerizable double bond from a novolak type epoxy resin as a starting material. As a result, the present invention was conducted with the aim of providing an ink composition for a solder resist capable of forming a coating film having excellent tack resistance, heat resistance, chemical resistance, adhesion, and resolution, and a method of using the same. Reached.

[0007]

The ink composition for a photocurable liquid solder resist according to the present invention comprises: (A) a novolak-type epoxy resin (I) having 4 or more nuclei; While introducing a (meth) acryloyl group by the reaction of the group,
A chain extender ( _IIa ) having two or more functional groups capable of reacting with the epoxy group via an epoxy group not participating in the above reaction;
A photopolymerizable resin obtained by increasing the molecular weight using at least one compound selected from the group consisting of a polyhydric phenol, a polyfunctional amine and a polyvalent thiol; (B) a photopolymerizable initiator; and (C) dilution. The gist is where the agent is contained. The photopolymerizable resin (A), relative to 1 chemical equivalent of epoxy groups in the novolak epoxy resin (I), the sum of the functional groups in (meth) acrylic acid and a chain extender (II _a) 0. 9 to 1.1 chemical equivalents,
Further, it is preferable that the amount of the chain extender ( _IIa ) used is obtained by reacting 0.2 to 0.8 mol with respect to 1 mol of the novolak type epoxy resin (I). The ink composition for a photocurable liquid solder resist of the present invention includes (A ₂ )
In a novolak-type epoxy resin (I) having 4 or more nuclei, a (meth) acryloyl group is introduced by a reaction between (meth) acrylic acid and an epoxy group, and an epoxy group and / or (meth) that do not participate in the above-mentioned reaction. Via a hydroxyl group generated by a reaction between acrylic acid and an epoxy group, the molecular weight is increased using a chain extender (II) having two or more functional groups capable of reacting with the epoxy group and / or the hydroxyl group, In the above hydroxyl group, 1
Resin obtained by reacting a polyfunctional (meth) acrylate (III) having two or more isocyanate groups and two or more photopolymerizable double bonds (B) a photopolymerization initiator and (C) a diluent And those containing An alkali-developable light containing a photopolymerizable resin (A ₃ ) (B) a photopolymerization initiator and a (C) diluent obtained by further reacting an acid anhydride with a hydroxyl group in the photopolymerizable resin. An ink composition for a curable liquid solder resist is also included in the present invention. In order to manufacture a resist pattern using the ink composition for a photocurable liquid solder resist of any of the above types, a) applying the ink composition for a photocurable liquid solder resist on a printed circuit board; B) heating and drying the coated film to form a tack-free resist layer on the substrate; c) pressing a pattern film against the resist layer; d) removing the resist layer from the substrate. Exposing through the patterning film to cure the exposed portion; and e) removing the patterning film and removing the non-exposed portion by development.

[0008]

The outline of the present invention is that a novolak type epoxy resin (I) is reacted with (meth) acrylic acid and a chain extender ( _IIa ) having two or more functional groups capable of reacting with an epoxy group to obtain _a high molecular weight resin. To obtain a photopolymerizable resin (A).

Further, it is formed on the hydroxyl group formed in the photopolymerizable resin (A) or by the reaction of the novolak type epoxy resin (I) with (meth) acrylic acid and (meth) acrylic acid with epoxy group. Reacting with a chain extender (II _b ) having two or more functional groups capable of reacting with the hydroxyl group which has been reacted with the hydroxyl group remaining in the photopolymerizable resin (A ′) having a high molecular weight. , 1
(Meth) acrylate (III) having two or more isocyanate groups and two or more photopolymerizable double bonds is reacted to obtain a photopolymerizable resin (A) having more double bonds introduced therein.
₂₎ to produce, on the photopolymerizable resin (A ₂₎ or the photopolymerizable resin (A), the by further reacting an acid anhydride, to produce a water-soluble photopolymerizable resin (A ₃₎ Things.

The novolak epoxy resin (I) used in the present invention includes a phenol novolak epoxy resin, a brominated phenol novolak epoxy resin,
There are cresol novolak type epoxy resins and the like, which are obtained by reacting each novolak resin with epichlorohydrin by a conventional method. Generally, the following structural formula can be shown.

[0011]

Embedded image (Wherein, R ¹ is a hydrogen atom or a methyl group, and R ² is a hydrogen atom, a halogen atom or an alkyl group.)

At this time, if n is 2 or more, the number of nuclei is 4 or more. More preferably, 2 ≦ n <10. In the novolak type epoxy resin (I), those having a value of n of 10 or more are difficult to obtain for reasons of production. N is 2
If it is smaller, unreacted substances are apt to remain when polymerized by the reaction with the chain extender (II), and the effect of increasing the molecular weight is not observed. The properties and physical properties are inferior.

The reaction of the novolak type epoxy resin (I) with (meth) acrylic acid and the chain extender (II) is carried out by first reacting the novolak type epoxy resin (I) with (meth) acrylic acid and then with the chain extender. (II) or a method of simultaneously reacting the novolak type epoxy resin (I) with (meth) acrylic acid and a chain extender (II), and further, a method of reacting the novolak type epoxy resin with (I) and a chain extender ( There is a method of reacting II) first and then reacting with (meth) acrylic acid, but there is no particular limitation, and it can be appropriately used depending on the type of the chain extender (II). Among the chain extenders (II), those having two or more functional groups capable of reacting with epoxy groups are chain extenders ( _IIa ), and those having two or more functional groups capable of reacting with hydroxyl groups are chain extended. Agent ( _IIb ).

The photopolymerizable resin (A) is obtained by reacting the novolak type epoxy resin (I) with a (meth) acrylic acid and a chain extender ( _IIa ) having two or more functional groups capable of reacting with an epoxy group. to obtain a), the sum of the functional groups per chemical equivalent of epoxy groups in the novolak epoxy resin (I) (meth) acrylic acid and a chain extender (II _a) in the 0.9 to 1 0.1 chemical equivalent, and the amount of the chain extender ( _IIa ) used is 0.2 to 0.8 mol, more preferably 0.3 to 0.7 mol, per 1 mol of the novolak type epoxy resin (I). The reaction is carried out at such a ratio as In addition, a chain extender (I
In increasing the molecular weight according to _Ia ), the number of nuclei is preferably 10 or more.

Examples of the chain extender ( _IIa ) include the following polyhydric phenols, polyfunctional amines, polyhydric thiols, and the like. Polyhydric phenol is 2 per molecule
It has two or more phenol groups, and examples thereof include bisphenol A, tetrabromobisphenol A, bisphenol F, bisphenol S, resorcinol, and hydroquinone.

The polyfunctional amine has two or more amino groups in one molecule, and among them, a polyfunctional amine having a secondary amino group which is unlikely to cause gelation during the polymerization is preferable. , 1,3-di- (4-piperidyl) -propane, homopiperazine and the like, and a piperazine-terminal-modified butadiene-acrylonitrile copolymer may be used as a part of the polyfunctional amine.

The polyvalent thiol has two or more thiol groups in one molecule, and includes 2,2-dimercaptodiethyl ether, 1,2-dimercaptopropane, 1,3
-Dimercaptopropanol-2, bis (2-mercaptoethyl) sulfide, esterified products of thioglycolic acid and a polyhydric alcohol, and the like.

In the reaction between the novolak type epoxy resin (I), (meth) acrylic acid and the chain extender ( _IIa ), the reaction proceeds at a relatively low temperature, such as when the chain extender ( _IIa ) is a polyhydric phenol. If it is difficult, the novolak-type epoxy resin (I), (meth) acrylic acid and the chain extender ( _IIa ) may be added simultaneously or stepwise in the above ratio in the presence or absence of a diluent described below. The reaction can be carried out at 80 to 130 ° C. in the presence of a polymerization inhibitor such as hydroquinone or oxygen and a reaction catalyst such as tertiary amine or tertiary phosphine.

Further, chain extender (II _a) is a polyvalent amine and when the relatively low temperature reaction tends to proceed, such as polyvalent thiols, novolak type epoxy resin (I) and chain extender ( the II _a) at room temperature to 80 ° C., in the presence of a diluent described later, it is reacted in the presence of a polymerization inhibitor such as hydroquinone and oxygen, then the reaction between (meth) acrylic acid 80 to 130
C. in the presence of a reaction catalyst such as a tertiary amine or tertiary phosphine.

On the other hand, the novolak type epoxy resin (I) is reacted with (meth) acrylic acid,
A chain extender having two or more functional groups capable of reacting with a hydroxy group generated by the reaction of acrylic acid and an epoxy group (I
In order to obtain a photopolymerizable resin (A ′) whose molecular weight has been increased by reaction with _Ib ), a novolak-type epoxy resin (I)
(Meth) acrylic acid is mixed at a ratio of 0.9 to 1.1 chemical equivalents with respect to 1 chemical equivalent of epoxy group in the solution, and in the presence or absence of a diluent described later, such as hydroquinone or oxygen. The reaction is carried out at 80 to 130 ° C. in the presence of a polymerization inhibitor or a catalyst such as a tertiary amine or a tertiary phosphine to obtain a (meth) acryl-modified epoxy resin having a (meth) acryloyl group, and then a novolak-type epoxy resin (I) 0.2 to 0.8 mol relative to 1 mol, more preferably preferably reacted 0.3-0.7 moles of chain extender and (II _b). Further, in increasing the molecular weight with the chain extender ( _IIb ), the number of nuclei is preferably 10 or more.

Examples of the chain extender ( _IIb ) include polyfunctional isocyanates. As the polyfunctional isocyanate, those having two or more isocyanate groups in one molecule can be used, and p-phenylene diisocyanate,
Diisocyanates such as 2,4- or 2,6-toluene diisocyanate (TDI), 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), tolylene diisocyanate, isophorone diisocyanate; triphenyl Methane triisocyanate,
Examples thereof include triisocyanates such as 1,3,6-hexamethylene triisocyanate.

The above polyfunctional isocyanate is used as a chain extender (I
In order to use it as I _b ), after obtaining the (meth) acryl-modified epoxy resin, the reaction may be further carried out at room temperature to 130 ° C. in the presence of a urethanization catalyst such as a tin compound or a lead compound. The polymerizable resin (A ′) can be obtained.

The photopolymerizable resin (A) of the present invention has a sufficient molecular weight and a photopolymerizable double bond. It can be used as an ink composition for a liquid solder resist. In order to further increase the photosensitivity, the photopolymerizable resin (A) or the photopolymerizable resin (A ') has an isocyanate group and two or more photopolymerizable double bonds in one molecule. It is preferable to introduce more photopolymerizable double bonds by reacting the functional (meth) acrylate (III).

The polyfunctional (meth) acrylate (III) used herein is, for example, diisocyanate (IV) having two isocyanate groups having different reactivity in one molecule.
And a polyfunctional (meth) acrylate having one hydroxyl group and two or more photopolymerizable double bonds in one molecule
By reacting (V).

As the diisocyanate (IV), 2,4-
Toluene diisocyanate, isophorone diisocyanate, hydrogenated 2,4-toluene diisocyanate, and the like. Examples of the polyfunctional (meth) acrylate (V) include glycerin di (meth) acrylate and tris (hydroxyethyl) isocyanurate di (meth) acrylate. ) Acrylate,
Examples include trimethylpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and the like.

The reaction between the polyfunctional (meth) acrylate (III) and the photopolymerizable resin (A) or the photopolymerizable resin (A ') is as follows:
Utilizing a urethane bond formed between an isocyanate group in the polyfunctional (meth) acrylate (III) and a hydroxyl group present in the photopolymerizable resin (A) or the photopolymerizable resin (A ') To introduce more photopolymerizable double bonds. The reaction ratio of the two is based on one chemical equivalent of the hydroxyl group in the photopolymerizable resin (A) or the photopolymerizable resin (A ′), and the polyfunctional (meth) acrylate (III).
0.05 to 0.5 mol is suitable, and the diisocyanate (I
When the reaction is carried out under the same conditions as the reaction between V) and the polyfunctional (meth) acrylate (V), a photopolymerizable resin (A ₂ ) is produced.

The reaction between the polyfunctional (meth) acrylate (III) and the photopolymerizable resin (A) is carried out by multifunctional (meth) acrylate.
(III) to introduce more photopolymerizable double bonds by utilizing a urethane bond formed between an isocyanate group in (III) and a hydroxyl group present in the photopolymerizable resin (A). is there. The reaction ratio between the two is suitably 0.05 to 0.5 mol of the polyfunctional (meth) acrylate (III) with respect to 1 chemical equivalent of the hydroxyl group in the photopolymerizable resin (A), and the diisocyanate (IV) and the polyfunctional ( When the reaction is carried out under the same conditions as the reaction of the (meth) acrylate (V), a photopolymerizable resin (A ₂ ) is produced. This photopolymerizable resin (A ₂ )
Has a large number of photopolymerizable double bonds and a sufficient molecular weight, and can constitute a photocurable solder resist ink having excellent performance.

In the present invention, the above-mentioned photopolymerizable resin (A) and the above-mentioned photopolymerizable resin (A ₂ ) may be further provided with water solubility as an added value. Those which, by reacting a photopolymerizable resin (A) or (A ₂₎ hydroxyl groups and the acid anhydride in, to produce a photopolymerizable resin in which a carboxyl group is introduced in the molecule (A ₃₎ This makes it possible to easily dissolve and remove the unexposed portion of the solder resist ink coating film with an alkaline aqueous solution.

Examples of the acid anhydride include phthalic anhydride, succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride,
Dibasic anhydrides such as hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, tetrabromophthalic anhydride, trimellitic acid, or aliphatic or Examples include tetrabasic dianhydrides such as aromatic tetracarboxylic dianhydrides, and one or more of these can be used.

The amount of the acid anhydride used depends on the amount of the photopolymerizable resin (A).
Alternatively, 0.1 to 0.9 mol is suitable per one chemical equivalent of the hydroxyl group in (A ₂ ), and the reaction conditions are the presence or absence of a diluent, and a polymerization inhibitor such as hydroquinone or oxygen. If necessary, the reaction can be carried out at 80 to 130 ° C. in the presence of a ring-opening reaction catalyst such as a tertiary amine.

Since the above-mentioned acid anhydride causes a ring-opening reaction by the reaction with the hydroxyl group, the hydroxyl group present in the photopolymerizable resin (A) or (A ₂ ) and the ring-opening group of the acid anhydride are converted. An ester bond is formed with one of the groups, and at the same time, a photopolymerizable resin (A ₃ ) having a carboxyl group introduced into the molecule is formed. When a carboxyl group introduction reaction is carried out with the acid anhydride on the photopolymerizable resin (A ₂ ), the reaction may be carried out before the reaction for introducing a photopolymerizable double bond with a polyfunctional (meth) acrylate (III). .

The photopolymerizable resin (A) thus obtained
_{Since 3} ) has a carboxyl group, water solubility can be imparted by neutralizing a part or all of the carboxyl group with an alkali and using it as a salt. Further, development with an alkaline aqueous solution becomes possible.

Examples of the alkali usable here include sodium carbonate, potassium carbonate, sodium hydroxide,
Alkali metal compounds such as potassium hydroxide; alkaline earth metal compounds such as calcium hydroxide; ammonia; monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monopropylamine, dimethylpropylamine, monoethanolamine, diethanolamine And water-soluble organic amines such as triethanolamine, ethylenediamine, diethylenetriamine, dimethylaminoethyl methacrylate, and polyethyleneimine. One or more of these can be used. The amount of the alkali 0.2 to 1.1 moles preferably on a carboxyl group-1 chemical equivalent in the photopolymerizable resin (A _3).

The photopolymerizable resins (A), (A)
₂ ) and (A ₃ ) show that the molecular weight is much larger than that of the conventional photopolymerizable resin having a novolak skeleton and the number of double bonds capable of photopolymerization in one molecule is significantly increased. As a result, a light curable solder resist ink composition capable of forming a cured coating film having excellent resolution can be provided even with a small amount of light irradiation.
Further, since the probability of the three-dimensional reaction becomes higher, the heat resistance, adhesion, and chemical resistance are also excellent. By adding the photopolymerization initiator (B) and the diluent (C) to the above photopolymerizable resin, the photocurable liquid solder resist ink composition of the present invention can be obtained.

As the photopolymerization initiator (B), known ones can be used, and specifically, benzoin such as benzoin, benzoin methyl ether and benzoin ethyl ether and alkyl ethers thereof; acetophenone, 2,2-dimethoxy-2 Acetophenones such as -phenylacetophenone and 1,1-dichloroacetophenone; anthraquinones such as 2-methylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone and 1-chloroanthraquinone; 2,4-dimethylthioxanthone;
Thioxanthones such as 2,4-diisopropylthioxanthone and 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone; 2-methyl-1- [4- (methylthio) phenyl] -2 -Morpholino-propan-1-one and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1; acylphosphine oxides and xanthones.

These photopolymerization initiators are used as one kind or as a mixture of two or more kinds, and are preferably contained in the ink composition for a photocurable liquid solder resist in an amount of 0.5 to 25% by weight. When the amount of the photopolymerization initiator is less than 0.5% by weight, the light irradiation time must be increased, or polymerization is difficult to occur even when the light irradiation is performed, so that an appropriate surface hardness can be obtained. Disappears. Also,
If the amount of the photopolymerization initiator exceeds 25% by weight, not only is there no merit but also the reduction of the amount of the photopolymerization initiator by increasing the photosensitivity of the photopolymerizable resin, which is the object of the present invention, is not preferable. .

As the diluent (C), a solvent or a diluent monomer capable of participating in the photopolymerization reaction may be used alone or in combination of two or more. The photopolymerizable resin (A),
5 to 50 parts by weight per 100 parts by weight of (A ₂ ) and (A ₃ )
It is preferable to mix 0 part by weight in accordance with the optimum viscosity of each coating method. a ₂₎ and (a ₃₎ is the physical properties of the solder resist preferable to blend 5 to 100 parts by weight per 100 parts by weight.

Examples of the solvent include hydrocarbons such as toluene and xylene; cellosolves such as cellosolve and butyl cellosolve; carbitols such as carbitol and butyl carbitol; esters such as cellosolve acetate and carbitol acetate; ketones such as methyl ethyl ketone. And ethers such as diethylene glycol dimethyl ether. Examples of the diluting monomer include diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, β-hydroxyethyl (meth) acrylate, (2-oxo-1,3-dioxolan-4-).
Yl) -methyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like.

In the ink composition for a photocurable liquid solder resist according to the present invention, talc,
Fillers such as clay and barium sulfate, coloring pigments, defoaming agents, coupling agents, leveling agents, etc., and epoxy resins and epoxy curing agents can also be added.

[0040]

The present invention will be specifically described below with reference to examples. The parts and percentages in the examples are on a weight basis. Synthesis Example 1 A reaction temperature of 5 parts was added to 222 parts of isophorone diisocyanate.
While maintaining at 0 ° C., a mixture of 596 parts of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (1: 1 by weight), 1.6 parts of dibutyltin dilaurate and 0.2 parts of benzoquinone was added to 1 part.
And then dropped at 50 ° C for 3 hours and then at 100 ° C
For 2 hours to obtain a mixture (III-1) with pentaerythritol tetraacrylate containing 64% of a polyfunctional (meth) acrylate having an isocyanate group and two or more photopolymerizable double bonds in one molecule. Was.

Synthesis Example 2 Phenol novolak type epoxy resin EPPN-201
To 234 parts (manufactured by Nippon Kayaku, epoxy equivalent: 187, n = 5) are added 92 parts of acrylic acid, 0.3 part of hydroquinone, 2.0 parts of triphenylphosphine, 50 parts of pentaerythritol tetraacrylate and 97 parts of butyl cellosolve acetate. After confirming that the acid value reached 6.4 by reacting at 110 ° C. for 14 hours, the mixture was cooled to 50 ° C., and 23 parts of hexamethylene diisocyanate and 0.5 part of dibutyltin dilaurate were added. ° C
For 2 hours, and confirming that the isocyanate group has disappeared by infrared absorption spectrum. The photopolymerizable resin (A)
Of pentaerythritol tetraacrylate and butyl cellosolve acetate containing 70%
1) was obtained.

Synthesis Example 3 To 200 parts of the mixture (A-1) obtained in Synthesis Example 2, 53 parts of tetrahydrophthalic anhydride and 23 parts of butyl cellosolve acetate were added and reacted at 110 ° C. for 4 hours to obtain a photopolymerization having an acid value of 102. containing 70% rESIN (a _3), to give a mixture of butyl cellosolve acetate, and pentaerythritol tetraacrylate and (a ₃ -1).

Synthesis Example 4 Cresol novolak type epoxy resin ECN1280
(Ciba Geigy, epoxy equivalent 227, n = 4.1)
To 114 parts, 36 parts of acrylic acid, 0.6 part of dimethylbenzylamine, 0.1 part of methylhydroquinone, 44 parts of toluene and 44 parts of ethyl carbitol acetate were added, and reacted at 110 ° C. for 13 hours to give an acid value of 3. After confirming that the mixture had reached 0, the mixture was cooled to 30 ° C., and 13 parts of toluene diisocyanate, the mixture obtained in Synthesis Example 1 (III-
1) 41 parts and 0.2 parts of dibutyltin dilaurate were added and reacted at 40 ° C. for 2 hours and further at 100 ° C. for 3 hours, and it was confirmed by an infrared absorption spectrum that the isocyanate group had disappeared. Then, 42 parts of tetrahydrophthalic anhydride was added, and the mixture was reacted at 100 ° C. for 5 hours. A mixture of ethyl carbitol acetate, toluene and pentaerythritol tetraacrylate containing 69% of a photopolymerizable resin (A ₃ ) having an acid value of 67 ( was obtained a ₃ -2).

Synthesis Example 5 Cresol novolak type epoxy resin EOCN-104
S (manufactured by Nippon Kayaku, epoxy equivalent 220, n = 7 to 8) 2
36 parts of tetrabromobisphenol A, 62.5 parts of acrylic acid, and ethyl carbitol acetate 65 in 20 parts
, 65 parts of toluene, 1.4 parts of trimethylbenzylammonium bromide and 0.1 part of benzoquinone, and the mixture was allowed to react at 110 ° C for 15 hours.
After confirming that the number of tetrahydrophthalic anhydrides became 8,
1 part, and further reacted at 100 ° C. for 5 hours. Then, 45 parts of pentaerythritol tetraacrylate was added, and 70% of a photopolymerizable resin (A ₃ ) having an acid value of 82 was contained.
Ethyl carbitol acetate, a mixture of toluene and pentaerythritol tetraacrylate (A ₃ -
3) was obtained.

Synthesis Example 6 To 220 parts of the cresol novolak type epoxy resin used in Synthesis Example 5 were added 36 parts of tetrabromobisphenol A, 75 parts of methacrylic acid, and 80 parts of ethyl carbitol acetate.
, 80 parts of toluene, 1.8 parts of triethylamine and 0.2 parts of benzoquinone were added and reacted at 110 ° C. for 18 hours. After confirming that the acid value of the reaction product was 3.5,
After cooling to 50 ° C., 0.7 part of dibutyltin dilaurate was added, and 164 parts of the mixture (III-1) obtained in Synthesis Example 1 was added dropwise at 50 ° C. over 1 hour, and then at 50 ° C. for 2 hours.
Further, the reaction was carried out at 100 ° C. for 2 hours, and it was confirmed by an infrared absorption spectrum that the isocyanate group had disappeared. Next, 50 parts of succinic anhydride was added and reacted at 100 ° C. for 5 hours, containing 70% of a photopolymerizable resin (A ₃ ) having an acid value of 58.
Ethyl carbitol acetate, a mixture of toluene and pentaerythritol tetraacrylate (A ₃ -
4) was obtained.

Synthesis Example 7 To 227 parts of the cresol novolak type epoxy resin used in Synthesis Example 4, 72 parts of acrylic acid, 1.1 parts of dimethylbenzylamine, 0.2 parts of methylhydroquinone, 60 parts of ethyl carbitol acetate and 60 parts of toluene And reacted at 110 ° C. for 12 hours. The acid value was 3.0. Then, 91 parts of tetrahydrophthalic anhydride was added and 1 part was added.
The mixture was allowed to react at 00 ° C. for 6 hours. After cooling, 44 parts of pentaerythritol tetraacrylate was added, and the acid value was 86. The comparison with ethyl carbitol acetate, toluene and pentaerythritol tetraacrylate containing 70% of photopolymerizable resin (1) A mixture (E-1) was obtained.

Synthesis Example 8 Phenol novolak type epoxy resin E. FIG. N. 43
1 (manufactured by Dow Chemical, epoxy equivalent 176, n = 0.
2) To 176 parts, 72 parts of acrylic acid, 1.1 parts of dimethylbenzylamine, 0.2 parts of methylhydroquinone, 45 parts of ethyl carbitol acetate and 45 parts of toluene were added, and the mixture was reacted at 110 ° C. for 12 hours. After confirming that the pH was 5.5, 44 parts of toluene diisocyanate and 0.4 part of dibutyltin dilaurate were added, and the mixture was reacted at 40 ° C. for 2 hours and further at 100 ° C. for 2 hours. confirmed.
Then add 76 parts of tetrahydrophthalic anhydride and add 100 ° C.
For 6 hours, adding 38 parts of pentaerythritol tetraacrylate, and adding an acid value of 76 to the comparative photopolymerizable resin (2).
Of ethyl carbitol acetate, toluene and pentaerythritol tetraacrylate containing 74% of (E-2).

Synthesis Example 9 To 227 parts of the cresol novolak type epoxy resin used in Synthesis Example 4, 72 parts of acrylic acid, 1.1 parts of dimethylbenzylamine, 0.2 parts of methylhydroquinone, 43 parts of pentaerythritol tetraacrylate and 43 parts of toluene
5 parts were added and reacted at 110 ° C. for 12 hours to obtain an acid value of 3.3.
And the comparative photopolymerizable resin (3) was
%, A comparative mixture of toluene and pentaerythritol tetraacrylate (E-3) was obtained.

Synthesis Example 10 200 parts of the comparative mixture (E-3) obtained in Synthesis Example 9 was added to
76 parts of the mixture (III-1) obtained in Synthesis Example 1 was heated to 50 ° C.
The reaction was carried out at 50 ° C. for 2 hours and then at 100 ° C. for 2 hours. After confirming that the isocyanate groups had completely disappeared by infrared absorption spectrum, the comparative photopolymerizable resin (4) was prepared. Comparative mixture of toluene and pentaerythritol tetraacrylate containing 68% (E-
4) was obtained.

Examples 1 to 5 and Comparative Examples 1 to 4 Photocurable liquid solder resist ink compositions were formulated according to the composition shown in Table 1, and the results evaluated by the following methods are shown in Table 2. <Evaluation at the time of exposure> An ink composition for a photocurable liquid solder resist was applied to a thickness of 20 to 30 μm on a degreased and washed 1.6 mm thick copper-clad laminate, and the coated composition was heated in a hot-air circulation drying oven. It was dried at 80 ° C. for 30 minutes to obtain a coating film. (1) Drying property of coating film The drying property of the coating film was evaluated according to JIS K-5400. ：: no tack was observed at all Δ: slight tack was observed ×: marked tack was observed

(2) Exposure sensitivity A 21-step Stofa step tablet was brought into close contact with the coating film,
Irradiation was performed at a light intensity of 500 mJ / cm ² using a 1 kW ultra-high pressure mercury lamp. Then, the coating film was subjected to a development test with respect to modified trichloroethane described below for Example 1 and Comparative Examples 3 and 4, and similarly for Examples 2, 3, 4, 5 and Comparative Examples 1 and 2, 1% Na ₂ CO 3 was used. ₃ A development test was performed on the aqueous solution, and the number of step tablets remaining on the copper foil was examined.

(3) Developability In Example 1 and Comparative Examples 3 and 4, the modified trichloroethane was used at 20 ° C.
5 and Comparative Examples 1 and 2 using a 1% aqueous solution of Na ₂ CO ₃ at 30 ° C. under a pressure of 2.1 kg / cm ² each.
Development was performed for 80 seconds, and the remaining resin was visually evaluated. ：: good developability: no resist left on copper surface ×: poor developability: little resist left on copper surface

<Evaluation of cured coating film> The coating film obtained in the same manner as in the evaluation at the time of exposure was exposed and developed at 500 mJ / cm ² ,
After being completely cured by heating at 150 ° C. for 30 minutes, the following evaluation was performed. (4) Hardness of coating film The coating film hardness was evaluated according to the test method of JIS K-5400, and the highest hardness at which a film was not damaged when a load of 1 kg was applied was evaluated using a pencil hardness tester. (5) Adhesion In accordance with the test method of JIS D-0202, a cross cut was made in a gobang shape, and then the peeling state after the peeling test with an adhesive tape was visually judged. ：: no change at 100/100 △: 80/100 to 99/100 ×: 0/100 to 79/100

(6) Solder Heat Resistance According to the test method of JIS D-0202, the film was immersed in a solder bath at 260 ° C. for 20 seconds, and the state of the coating film after immersion was evaluated. ：: No abnormality in appearance of coating film ×: Bulge, melting, and peeling of appearance of coating film (7) Electroless gold plating resistance 1A / using Autronec CI (gold plating solution manufactured by Celllex, USA) After gold plating was performed at a current density of dm ² for 15 minutes to attach gold having a thickness of 2 μm, the coating film was subjected to a peeling test using an adhesive tape, and the peeled state was visually determined. ：: not peeled at all △: slightly peeled ×: peeled 20% or more of the whole

[0055]

[Table 1]

[0056]

[Table 2]

[0057]

According to the present invention, the photopolymerizable resin has a higher molecular weight and a larger number of double bonds than the conventional photopolymerizable resin having a novolak skeleton. Since the resin is easily cured by a slight photopolymerization reaction and the probability of three-dimensionalization becomes higher, even if the amount of photoinitiator or the amount of light irradiation or irradiation time is small, Thus, it was possible to provide a photocurable liquid solder resist ink composition capable of forming a cured film having excellent resolution, heat resistance, adhesion, chemical resistance and tack-free property. Further, those having a carboxyl group introduced into the photopolymerizable resin can be developed with an aqueous alkali solution.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G03F 7/027 515 G03F 7/027 515 7/028 7/028 (56) References JP-A-2-97513 (JP, A) JP-A-3-59022 (JP, A) JP-A-5-179185 (JP, A) JP-A-6-93221 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) C09D 11/00-13/00 C08F 299/00-299/02 C08G 18/67 C08G 59/16-59/17 G03F 7/027-7/031

Claims (5)

(57) [Claims] (A) In a novolak type epoxy resin (I) having 4 or more nuclei, a (meth) acryloyl group is introduced by a reaction between (meth) acrylic acid and an epoxy group and does not participate in the above reaction. Via an epoxy group,
As chain extenders ( _IIa ) having two or more functional groups capable of reacting with the epoxy group , polyhydric phenols, polyfunctional amines and
And at least one selected from the group consisting of polythiols and polyvalent thiols
An ink composition for a photocurable liquid solder resist, comprising: a photopolymerizable resin obtained by increasing the molecular weight by using the compound of (B); (B) a photopolymerizable initiator; and (C) a diluent. 2. The photopolymerizable resin (A) according to claim 1, wherein
1 chemical equivalent of epoxy group in rack type epoxy resin (I)
The amount in (meth) acrylic acid and the chain extender ( _IIa )
The sum of functional groups is 0.9 to 1.1 chemical equivalents, and a chain extender
(II _a) novolak type epoxy resin (I) used in an amount of 1 Mo
The photocurable liquid solder resist ink composition according to claim 1, which is obtained by reacting 0.2 to 0.8 mol with respect to the amount of the compound. 3. (A ₂ ) a novolak type having 4 or more nuclei
In the epoxy resin (I), (meth) acrylic acid
Introduction of (meth) acryloyl group by reaction of oxy group
And an epoxy group not participating in the above reaction and / or
Or by the reaction of (meth) acrylic acid with epoxy groups
Via the resulting hydroxyl group, the epoxy group and
And / or two or more functional groups capable of reacting with a hydroxyl group
The molecular weight is increased using a chain extender (II) having
One isocyanate group and two or more
Multifunctional (meth) acryl having photopolymerizable double bond
An ink composition for a photocurable liquid solder resist, comprising: a photopolymerizable resin obtained by reacting a rate (III) with (B) a photopolymerization initiator and (C) a diluent. 4. Photopolymerizable resin (A ₃ ) obtained by reacting an acid anhydride with a hydroxyl group in the photopolymerizable resin according to claim 1, and (B) photopolymerization initiation. An ink composition for a photocurable liquid solder resist, comprising an agent and (C) a diluent. (5) The photocuring according to claim 1.
Resist using an ink composition for conductive liquid solder resist
In producing the pattern a) The ink composition for a photocurable liquid solder resist
Coating on a printed circuit board, b) Heat-dry the coated film to make it a tack-free cash register.
Forming a test layer on the substrate, c) Step of pressing a pattern film onto the resist layer
About d) passing the resist layer through the patterning film
Exposing, curing the exposed part, e) peeling off the pattern film and developing
Step of removing unexposed parts Photocurable liquid solder resist characterized by passing through
How to use the ink composition for printing.