JPH043067A - Photosetting resin composition - Google Patents

Abstract

PURPOSE:To allow development with an aq. alkaline soln. having excellent pigment dispersibility by incorporating a specific photosetting resin, a compd. having an epoxy group and a photopolymn. initiator. CONSTITUTION:The photosetting resin obtd. by bringing the reactant of a novolak type epoxy compd. and unsatd. monocarboxylic acid, the reactant of diisocyanates and monovalent alcohols, and the compd. selected from arom. polybasic acid anhydride, aliphat. polybasic acid anhydride and alicyclic polybasic acid anhydride into reaction, the compd. having the epoxy group and the photopolymn. initiator are incorporated into this compsn. The alkaline developable photosetting resin compsn. which has the good wettability with inorg. pigments and the excellent dispersion stability is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a photocurable resin composition that can be developed with an alkaline aqueous solution. More specifically, the present invention relates to a photocurable resin composition that can be used in a photo solder resist for printed wiring boards and that can be developed with an alkaline aqueous solution that has extremely excellent pigment dispersibility.

(Prior art) Solder resist for printed wiring boards has traditionally been pattern-printed using the screen method, but there are problems such as bleeding, edge breakage, and pattern misalignment during printing, and it is difficult to make circuits smaller and more dense. I can't handle it (it's becoming more and more).

Photography has been developed as a method to solve these problems, and various liquid developable resins have been proposed.

For example, JP-A-60-208377 discloses a resin composition for solder resist ink in which epoxy and unsaturated basic acid are reacted. Also, JP-A-61-2
No. 72 discloses a developable product made by reacting a reaction product of an epoxy compound with an unsaturated basic acid, and a reaction product of a diisocyanate and a poly(meth)acrylate containing one hydroxyl group in one molecule. A resin composition for liquid solder resist ink is shown.

However, since all of these resin compositions for solder resist ink require the use of organic solvents during development, they pose problems in terms of working environment and economy.

On the other hand, in order to solve the problems caused by organic solvents, alkali-developable photosensitive resins that can be developed with alkaline aqueous solutions have been proposed. For example, JP-A-61-243869 proposes an alkali-developable liquid resist obtained by reacting a reaction product of a novolak epoxy resin and acrylic acid with a polybasic acid anhydride. Also, JP-A-63-2
No. 05650 proposes an alkali-developable photosensitive resin in which a reaction product of a novolac epoxy resin and acrylic acid is reacted with a diisocyanate, a polyacrylate containing one hydroxyl group per molecule, and a polybasic acid anhydride. ing.

(Problem to be solved by the invention) However, these alkali-developable photosensitive resins,
Wetting with the inorganic extender pigment used as a polymerization shrinkage softener added during resist production is not always good, and in order to obtain sufficient dispersibility by kneading with a three-roll mill, it is necessary to pass it through the rolls five or more times. However, the productivity was poor compared to 3 rolls for general ink.

The problem to be solved by the present invention is to provide an alkali-developable photocurable resin composition that has good wettability with inorganic extender pigments and excellent dispersion stability.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides (1) (a) a reaction product of a novolac type epoxy compound and an unsaturated monocarboxylic acid (hereinafter referred to as reaction product (A)). ), (b) reaction product of diisocyanates and monohydric alcohols (hereinafter referred to as
It is called reactant (B). ) and (c) a compound selected from the group consisting of aromatic polybasic acid anhydrides, aliphatic polybasic acid anhydrides, and alicyclic polybasic acid anhydrides (hereinafter referred to as compound (C)). The present invention provides a photocurable resin composition comprising: (2) a compound having an epoxy group; and (3) a photopolymerization initiator.

Examples of the novolak-type epoxy compound used as a raw material for the reactant (A) used in the present invention include a polycondensate of phenol and formaldehyde, or a polycondensate of alkylphenols having an alkyl group having 1 to 9 carbon atoms and formaldehyde. Examples include phenol/novolac type epoxy resins, cresol/novolak type epoxy resins, etc. obtained by addition-reacting epichlorohydrin or β-methylepichlorohydrin to the condensate. It is appropriate to use epoxy compounds of 3 to 8 types, that is, trinuclear to henuclear novolac type epoxy compounds. If less than trinuclide is used, the surface curing time of the resulting photocurable resin composition will tend to be longer, which is undesirable; if more than trinuclide is used, This is not preferable since it tends to gel easily during the urethanization reaction. When a polyfunctional bisphenol type epoxy resin having pendant hydroxyl groups is used, the curability and heat resistance of the photocurable resin composition are lower than when using the various novolac type epoxy compounds listed above. Although it tends to have poor properties, it is possible to use a small amount in combination without affecting the curability and heat resistance.

Examples of the unsaturated monocarboxylic acid serving as a raw material for the reactant (A) used in the present invention include acrylic acid, methacrylic acid, crotonic acid, and cinnamic acid. Among these, acrylic acid is particularly preferred. .

Two or more of these unsaturated monocarboxylic acids can also be used in combination.

The usage ratio of the novolac type epoxy compound and the unsaturated monocarboxylic acid is such that the equivalent ratio of the epoxy group in the novolac type epoxy compound to the carboxyl group in the unsaturated monocarboxylic acid is epoxy group: carboxyl group = 1.0 to 1. .7:
The ratio is preferably 1.0.

The reactant (A) used in the present invention is the above-mentioned Nopola 1. It can be easily obtained by dissolving a type epoxy resin in a solvent such as ethyl cellosolve acetate, adding an unsaturated monocarboxylic acid, a polymerized cotton thread agent, and an amine catalyst, and reacting at about 90°C with stirring.

Examples of diisocyanates used as raw materials for the reactant (B) used in the present invention include 2,4- or 2.6-
-) Diisocyanate monomers such as lylene diisocyanate, xylylene-1,4-diisocyanate, hydrogenated xylylene-1,4-diisocyanate, hexamethylene diisocyanate, inphorone diisocyanate, diphenylmethane diisocyanate, toluidine diisocyanate or lysine diisocyanate, and these diisocyanates. Examples include reaction products (urethane prepolymers) having terminal isocyanate groups between monomers and known and commonly used diols.

Examples of monohydric alcohols serving as raw materials for the reactant (B) used in the present invention include n-
Examples include derivatives of polyhydric alcohols such as 1 so-tert- saturated alcohol, allyl alcohol, oleyl alfur unsaturated alcohol, cellosolve, carpitol, etc. Among these, saturated alcohol having 4 to 15 carbon atoms, oleyl Alcohols are particularly preferred. These monohydric alcohols can be used alone or in plurality.

The usage ratio of diisocyanates and monohydric alcohols is such that the equivalent ratio of isocyanate groups in the diisocyanates to hydroxyl groups in the monohydric alcohols is NGO:OH=2.
．． A ratio of 0:1.0 to 1.3 is preferable.

The reactant (B) used in the present invention is a mixture of a solvent such as ethyl cellosolve acetate, the above diisocyanates, and a tin catalyst, and while heating and stirring the mixture to about 60°C, the above monohydric alcohol is added dropwise into the mixture. By,
easily obtained.

Examples of the compound (C) used in the present invention include phthalic anhydride, trimeric anhydride, pyromellitic anhydride, hetacetic anhydride, tetrachlorophthalic anhydride, maleic anhydride, conolylic anhydride, and dodecenyl anhydride. Succinic anhydride, citraconic anhydride, itaconic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, 3
, 6-nindomethylenetetrahydrophthalic anhydride, rS
Examples include MT-700J (manufactured by Nippon Terpene Chemical Co., Ltd.).

Next, reactions with reactant (A), reactant (B), and compound (C) will be explained.

The proportions of reactant (A), reactant (B) and compound (C) used are hydroxyl group in reactant (A), isocyanate group in reactant (B), and acid group and acid in compound (C). The molar ratio of anhydride groups is preferably (incyanate group+acid anhydride group):hydroxyl group=1.0 to 0, 1:1.0.

Examples of the solvent used in this reaction include ethyl acetate, methyl ethyl ketone, toluene, methyl cellosolve acetate, ethyl cellosolve acetate, ethyl cellosolve acetate, ethyl carpitol acetate, butyl carpitol acetate, etc., which are commonly used in urethanization reactions. .

The photocurable resin used in the present invention is prepared by mixing the above reactant (A) and the reactant (B) in the above solvent, reacting at about 60°C with stirring, and then adding the above polybasic acid anhydride. Add,
It can be easily obtained by reacting at about 100°C with stirring.

The compound having an epoxy group used in the present invention is blended for the purpose of thermosetting the photocurable resin composition of the present invention.

The compound having an epoxy group used in the present invention includes:
For example, phenol novolac type epoxy resin, Talesol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, alicyclic epoxy resin, N-
Examples include glycidyl-type epoxy resins.

Examples of the photopolymerization initiator used in the present invention include benzoin and its alkyl ethers such as benzoin, pendipentathyl ether, and benzoin isopropyl ether; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, and 2,2- Jetoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenylketone, 2-
Methyl-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-hydroxy-2-methyl-
Acetophenones such as 1-phenylpropan-1-one, p-dimethylaminoacetophenone; 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert
-Anthraquinones such as butylanthraquinone and 1-chloroanthraquinone; benzophenones such as benzophenone, methyl 0-benzoylbenzoate, p, p-bisdimethylaminobenzophenone, p, p-bisdiethylaminobenzophenone; 2,4-dimethylthioxanthone , 2,4-dimethylthioxanthone, 2-chlorothioxanthone, and the like; ethyl p-dimethylaminobenzoate, and the like, but these compounds can be used alone or in combination.

The usage ratio of the photocurable resin, the compound having an epoxy group, and the photopolymerization initiator is 5 to 80 parts by weight of the compound having an epoxy group and 0.1 to 0.1 to 0.1 parts by weight of the photopolymerization initiator per 100 parts by weight of the photocurable resin. The amount is preferably in the range of 30 parts by weight, and 1 part of the compound having an epoxy group is added to 100 parts by weight of the photocurable resin.
A range of 0 to 50 parts by weight and a range of 0.5 to 20 parts by weight of the photopolymerization initiator is particularly preferable. If the amount of the compound having an epoxy group used is less than 5 parts by weight based on 100 parts by weight of the photocurable resin, the hardness of the coating film due to heating after alkaline development tends to decrease and the solder resistance tends to deteriorate. If the amount exceeds 80 parts by weight, the alkali developability tends to deteriorate, which is not preferable. In addition, photocurable resin 10
The amount of photopolymerization initiator used is 0.0 parts by weight. 1
If it is less than 30 parts by weight, the photopolymerizability tends to be slow and sensitivity decreases, and if it exceeds 30 parts by weight, the sensitivity tends to be too high and unirradiated areas also polymerize, resulting in poor development. Therefore, it is not desirable.

A photopolymerizable monomer and/or an organic solvent can be used in the photocurable resin composition of the present invention, if necessary.

Examples of photopolymerizable monomers that can be used as necessary in the photocurable resin composition of the present invention include EVA, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and pentaerythritol tetra( meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexaacrylate, 1,6-hexanethiol di(meth)acrylate, 2-hydroxyethyl(meth)acrylate, polyethylene glycol di(meth)acrylate
Acrylate, polybrobylene glycol di(meth)acrylate, bis[(meth)acryloyl ethoxy]bisphenol A1 Methacrylamide, N-vinylpyrrolidone, bis[(meth)acryloxyethyl coisocyanurate, tris[(meth)acryloxyethyl ] Examples include inocyanurate.

In addition, examples of organic solvents that can be used as necessary in the photocurable resin composition of the present invention include methyl ethyl ketone, ethyl acetate, isofurobanol, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve acetate, and ethyl carpitol acetate. etc. can be mentioned.

When the photocurable resin composition of the present invention is used as a photosolder resist for printed wiring boards, in addition to the above photopolymerizable monomer and organic solvent, barium sulfate, silica, talc/mica, and clay may be added as necessary. Inorganic extender pigments such as phthalocyanine green and phthalocyanine blue; thermosetting agents such as hexamethoxymethylmelamine and hexabutoxymethylmelamine; curing accelerators such as dicyandiamide and Amikinia PN-23J (manufactured by Ajinomoto); Stabilizers such as hydroquinone, hydroquinone mo/methyl ether, tert-butylno\hydroquinone, and phenothiazine; or antifoaming agents, leveling agents, etc. can be added.

Examples of methods for applying the thus produced photo solder resist onto a printed wiring board include a screen printing method, a spray method, a roller coater method, a curtain coater method, and a dipping method. By these methods, the photo solder resist is applied onto the substrate with a dry coating thickness of 20 mm.
After coating to a thickness of ~40 microns, a coating film is formed by evaporating the organic solvent.

The formed coating film is irradiated with a high-pressure mercury lamp, metal 7% Ride lamp, etc. to harden the necessary areas, and the unexposed areas are dissolved in a dilute alkaline aqueous solution such as 1 to 3% sodium carbonate or caustic soda to form a pattern. A hardened coating film can be formed.

It is desirable to heat the patterned coating film in order to impart resistance to it. The heating conditions are preferably 130 to 160°C for 10 to 60 minutes.

(Example) Next, the present invention will be specifically explained using synthesis examples, examples, and comparative examples. In the following examples, "parts" and "%" are based on weight unless otherwise specified.

Synthesis Example 1 To a cellosolve acetate solution containing 1.02 equivalents of a cresol novolac type epoxy compound having an epoxy equivalent of 227 and an average of 6 phenol core residues and epoxy groups in one molecule, 1 equivalent of acrylic acid and 0.00% of hydroquinone were added. 1
5g and N,N-dimethylbenzylamine i, 5
g was added thereto, and the mixture was reacted at 90° C. until the acid value became 5 or less to obtain a reaction product (A).

Next, 0.5 equivalents of tolylene diisocyanate and 0.3 equivalents of oleyl alcohol were mixed in a cellosolve acetate solvent in the presence of 0.017 g of dibutyltin dilaurate (60%).
The reaction product (B) obtained by reacting at 60°C for 3 hours was added to the previous reaction product (A), and the mixture was reacted at 60°C for 10 hours.

After the reaction was completed, 0.6 mol of succinic anhydride was added to the reaction mixture, and the mixture was reacted at 100° C. for 5 hours. This reaction results in 1
A resin having an average of 5.5 acryloyl groups and 3.6 carboxyl groups per molecule was obtained. This is referred to as photocurable resin A.

Synthesis Example 2 1 equivalent of acrylic acid and hydroquinone are added to a cellosolve acetate solution containing 1.05 equivalents of a cresol novolac type epoxy compound having an epoxy equivalent of 213 and an average of 4.5 phenol core residues and epoxy groups in one molecule. 0
．． 15g and N,N-dimethylbenzylamine1.
5 g was added and reacted at 90° C. until the acid value became 5 or less to obtain a reaction product (A).

Next, a reaction product obtained by reacting 0.44 equivalents of tolylene diisocyanate and 0.24 equivalents of 2-ethylhexyl alcohol at 60°C for 3 hours in the presence of 0.02 g of dibutyltin dilaurate in a cellosolve acetate solvent ( B
) was added to the above reaction product (A) and reacted at 60°C for 10 hours. After the reaction was completed, 0.4 mol of maleic anhydride was added,
The reaction was carried out at 90°C for 5 hours. Through this reaction, a resin having an average of 4.5 acryloyl groups and 1.8 carboxyl groups per molecule was obtained. This is referred to as photocurable resin B.

Synthesis Example 3 A cellosolve acetate solution containing 1.05 equivalents of a phenol novolac type epoxy compound having an epoxy equivalent of 186 and an average of 4.5 phenol core residues and epoxy groups in one molecule was added with 1 equivalent of acrylic acid and hydroquinone. 0
．． 15g and N,N-dimethylbenzylamine1.
5 g was added and reacted at 90°C until the acid value became 5 or less to obtain a reaction product (A).

Next, the reaction product (B ) was added to the previous reaction product (A) and reacted for 60° CIO time. After the reaction was completed, 0.5 mol of hexahydrophthalic anhydride was added and the mixture was reacted at 100°C for 5 hours. This reaction results in an average of 4.5 acryloyl groups per molecule,
A resin having 18 carboxyl groups was obtained. This is referred to as photocurable resin C.

Synthesis Example 4 In the same manner as Synthesis Example 1, except that 0.3 equivalents of pentaerythritol triacrylate was used in place of 0.3 equivalents of oleyl alcohol, an average of 7 acryloyl groups per molecule was obtained. A resin having .2 carboxyl groups and 3.6 carboxyl groups was obtained. This is used as a photocurable resin.

Synthesis Example 5 In Synthesis Example 2, 2-ethylhexyl alcohol 0.
In the same manner as in Synthesis Example 2, except that 0.24 equivalents of pentaerythritol triacrylate was used instead of 24 equivalents, on average 6.5 acryloyl groups and 1.8 carboxyl groups per molecule. A resin having the following properties was obtained. This is referred to as photocurable resin E.

Synthesis Example 6 In the same manner as Synthesis Example 3, except that 0.12 equivalents of pentaerythritol triacrylate was used instead of 0.12 equivalents of n-butanol, the average amount of acryloyl groups per molecule was A resin having 5.3 carboxyl groups and 1.8 carboxyl groups was obtained. This is photocurable resin F
shall be.

Examples 1 to 4, Comparative Examples 1 to 3 Using the photocurable resins A-F obtained in Synthesis Examples 1 to 6, a compound having an epoxy group, a photoinitiator, a photopolymerization monomer, an inorganic extender pigment, a colored pigment , a thermosetting agent, a curing accelerator, a polymerization inhibitor, an antifoaming agent, and an organic solvent are kneaded using a three-roll mill for testing in the proportions (parts by weight) shown in Table 2 to produce a photo solder resist. was prepared.

According to JIS K5701-4°3, a grindmeter measurement value of 2 or less for determining kneaded dust was considered to be a pass, and the results are shown in Table 1. As is clear from Table 1, photocurable resins A-C required fewer passes through the roll mill than photocurable resins D-F.

These photo solder resists were applied by screen printing to the entire surface of a printed wiring board on which a pattern had been formed by etching in advance, and then dried in a hot air circulation drying oven for 8 hours.
A test piece was prepared by drying at 0°C for 20 minutes.

Next, place a negative film on the test piece 8
kW ultra-high pressure mercury lamp ()＼Itek HTE-105-
500 mJ/cm2 was irradiated using a mold 8). After exposure, in a 1% by weight aqueous sodium carbonate solution at 40°C.
It was developed for 0 seconds and the unexposed areas were removed. Next, heat treatment was performed at 150° C. for 30 minutes in a hot air circulation drying oven.

Table 2 shows the results of the test pieces' dryness to the touch, alkali developability, coating hardness, adhesion to printed wiring boards, soldering heat resistance, solvent resistance, acid resistance, and insulation resistance.

The performance evaluation methods and criteria in Table 2 above are as follows:
It is as follows.

[Dryness to Touch] The dryness to touch of the coating film was evaluated according to the test method of JIS K-5400.

○: No tack observed at all △: Slight tack observed ×: Significant tack observed [Alkaline developability] A 1% by weight aqueous sodium carbonate solution heated to 40°C was used as the developer. spray pressure 2 kg/cm”
The film was developed for 1 minute under the following conditions, and the state of development was visually evaluated using a microscope.

O: Completely developed △: There are some areas that cannot be developed X: Not developed [Coating film hardness] The hardness of the coating film was evaluated by pencil hardness according to the test method of JIS D-0202.

[Adhesion] Immediately after affixing "cellophane tape" to the coating film on which cross-strength and tension were formed on each test piece in accordance with the test method of JIS D-LO202,
It was peeled off and the peeled state was visually judged.

○: 100/100, no change observed △:
Items with peeling observed between 70/100 and 99/100 The process of floating for 10 seconds was defined as one cycle, and this process was repeated 5 times to evaluate blistering and adhesion of the coating film.

O: Total (No change observed △: Less than 10% of the wall coating has peeled off. After that, the appearance and adhesion of the coating film were evaluated.

O: No change observed △: Swelling ×: Swelled and fell off
After immersion for 0 minutes, the appearance and adhesion of the coating film were evaluated.

○: No change observed △: Change observed X: Swelled and fell off The insulation properties were displayed as 1-minute values at DC 500 V using rTR-8601J manufactured by Atopan Test.

(Effects of the Invention) The photocurable resin composition of the present invention can be used as a photo solder resist in the same way as conventional photocurable resin compositions,
Compared to conventional photocurable resin compositions, it had better wetting properties with inorganic extender pigments, so it had excellent kneading properties using a three-roll mill.

Therefore, the photocurable resin composition of the present invention is useful as a material for a photo solder resist that can reduce production costs.

Agent: Patent Attorney Katsutoshi Takahashi

Claims (1)

[Claims] 1. (1) (a) a reaction product of a novolac type epoxy compound and an unsaturated monocarboxylic acid, (b) a reaction product of a diisocyanate and a monohydric alcohol, and (c) an aromatic compound. A photocurable resin obtained by reacting a compound selected from the group consisting of polybasic acid anhydrides, aliphatic polybasic acid anhydrides, and alicyclic polybasic acid anhydrides, (2) a compound having an epoxy group, and (3) A photocurable resin composition containing a photopolymerization initiator. 2. Contains (1) 10 to 50 parts by weight of a compound having an epoxy group and (3) 0.5 to 20 parts by weight of a photopolymerization initiator per 100 parts by weight of the photocurable resin. The photocurable resin composition according to claim 1.