JPH08123027A - Photo-soldering resist - Google Patents

Abstract

PURPOSE: To obtain a photo-soldering resist giving an uncured coating film readily soluble in an aq. alkali soln. and highly sensitive to active energy beams and giving a cured coating film excellent in hardness, adhesion and heat, solvent and chemical resistances. CONSTITUTION: This photo-soldering resist is made of a polymerizable compsn. having 40-100mgKOH/g acid value obtd. by allowing a dipentaerythritol deriv. having 4.0-5.6 (meth)acryloyl qroups and 0.4-2.0 hydroxyl groups on average in one molecule to react with phthalic anhydride or maleic anhydride.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photo solder resist material (hereinafter simply referred to as a photo solder resist) capable of forming a solder resist film by a photoengraving method. More specifically, it relates to a printed wiring board and the like. The present invention relates to a photo solder resist comprising a curable composition having a property that it can be applied on the surface of a base material without generating bubbles, and a film cured with an active energy ray has excellent heat resistance, electric insulation and solvent resistance. is there. The photo solder resist of the present invention can be used for printed wiring board production, metal precision processing, and the like.

[0002]

2. Description of the Related Art A solder resist is applied to a printed circuit board or the like to form a heat-resistant and insulative film, and has a function of preventing bridges and stabilizing circuit insulation when soldering components to the printed circuit board. Is. Conventionally, solder resist has been used by the method of forming a pattern film by screen printing, but as the density of printed wiring boards becomes higher, circuit pattern exposure by patterning by screen printing (edge cuts) and unnecessary parts are unnecessary. Fogging on the face has become a problem.

In order to solve the above problem, a photo solder resist for forming a pattern film by a photoengraving method,
Alternatively, a dry film type solder resist has been developed. Among them, the method of using the photo solder resist is to apply a liquid resist material to the entire surface of the base material with a roll coater or the like, and then form a pattern of the cured film by photoengraving method. In addition, the embeddability between circuits is also good. For these reasons, the demand for photo solder resist has increased in recent years. In the photo solder resist, an uncured portion, that is, an unexposed portion is washed away with a developing solution, and an organic solvent or an alkaline aqueous solution is used as the developing solution, but the latter is safer and saves resources. Therefore, it is the mainstream.

[0004]

DISCLOSURE OF THE INVENTION The present invention is a photo solder resist developed by an alkaline aqueous solution, wherein the resulting cured film has adhesion, electrical insulation, solder heat resistance, solvent resistance, alkali resistance, The object was to provide a solder resist having excellent acid resistance and plating resistance.

[0005]

Means for Solving the Problems The inventors of the present invention have completed the present invention as a result of extensive studies to solve the above problems. That is, the present invention has an average of 4.0 to 1 molecule.
5.6 (meth) acryloyl groups and a dipentaerythritol derivative having 0.4 to 2.0 hydroxyl groups are obtained by reacting phthalic anhydride or maleic anhydride with an acid value of 40 to 100 mgKOH / g is a photosolder resist composed of the polymerizable composition, and further is a photosolder resist containing the above polymerizable composition, an epoxy resin, a curing agent for the epoxy resin, a photopolymerization initiator and a diluent as essential components.

The present invention will be described in more detail below. The dipentaerythritol derivative in the present invention is
An average of 4.0 to 5.6 hydroxyl groups among the 6 hydroxyl groups contained in dipentaerythritol are converted to (meth) acryloyl groups, which is a compound of dipentaerythritol and (meth) acrylic acid. It is synthesized by an esterification reaction. In the above reaction, it is preferable to charge the reactor at a ratio of 6 to 8 mol of (meth) acrylic acid per mol of dipentaerythritol, and the reaction is usually carried out in an organic solvent. Examples of the organic solvent include benzene, toluene, xylene, ethyl acetate, butyl acetate, methyl isobutyl ketone, and the like. Further, acidic catalysts such as sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid, and hydroquinone, hydroquinone monomethyl ether,
It is preferable to add a polymerization inhibitor such as catechol, pyrogallol, phenothiazine and N-nitrosophenylhydroxylamine aluminum salt to the reaction system.

The reaction rate of the esterification reaction can be confirmed by the amount of dehydration accompanying the formation of ester, and the reaction is carried out when a dehydration amount of 4.0 to 5.6 mol per mol of dipentaerythritol is obtained. And the excess (meth) acrylic acid is extracted and removed with alkaline water to obtain a dipentaerythritol derivative. In addition,
The dipentaerythritol derivative obtained by the above reaction is a mixture containing compounds having different numbers of (meth) acryloyl groups or hydroxyl groups, and the number of hydroxyl groups is determined by a titration method or the like.

When the number of (meth) acryloyl groups in the dipentaerythritol derivative is less than 4, the polymerizable composition is inferior in sensitivity to active energy rays and the cured coating film obtained is inferior in chemical resistance. On the other hand, the (meth) acryloyl group in the dipentaerythritol derivative is
When it exceeds 5.6, that is, when the number of hydroxyl groups is less than 0.4, the amount of the acid anhydride added to the dipentaerythritol derivative is too small, and the uncured film of the resulting polymerizable composition is soluble in an alkaline aqueous solution. do not become.

The polymerizable composition in the present invention is a polymerizable composition having an acid value of 40 to 100 mgKOH / g, which is obtained by reacting the dipentaerythritol derivative with phthalic anhydride or maleic anhydride. It is polymerized by irradiation with active energy rays such as ultraviolet rays or electron rays to form a cured product. In the reaction of an aliphatic or alicyclic acid anhydride other than phthalic anhydride or maleic anhydride with a dipentaerythritol derivative, the sensitivity of the resulting composition to ultraviolet light is poor and a hardened product cannot be obtained. . When the acid value of the polymerizable composition is less than 40 mgKOH / g, the composition does not become soluble in an alkaline aqueous solution, while 1
If it exceeds 00 mgKOH / g, the resolution of the resist pattern is poor and the cured coating film is also poor in alkali resistance.

In the reaction of the dipentaerythritol derivative with phthalic anhydride or maleic anhydride (these may be collectively referred to as an acid anhydride hereinafter), the hydroxyl group in the dipentaerythritol derivative and the acid anhydride are reacted in equimolar amounts. Then, a carboxyl group equimolar to the reacted acid anhydride is introduced into the dipentaerythritol derivative.

The acid value of the resulting polymerizable composition is controlled by the amount of acid anhydride reacted with the hydroxyl group in the dipentaerythritol derivative. For example, acid value is 80mgKOH
In order to obtain a curable composition of about / g, hydroxyl groups of 1.0 to 2.
Strictly speaking, it depends on the number of hydroxyl groups in the dipentaerythritol derivative to be used per 1 mol of the dipentaerythritol derivative having 0, but about 0.9 mol of acid anhydride may be reacted. The amount of acid anhydride used is
It is preferable to set the equivalent amount of the hydroxyl group in the dipentaerythritol derivative used to the upper limit. The use of acid anhydride in excess of the amount of hydroxyl groups leaves excess acid anhydride in the reaction product.

In the above reaction, tertiary amines such as N, N-dimethylbenzylamine, triethylamine, N, N-dimethylaniline; quaternary ammonium salts such as tetradiethylammonium chloride, tetrabutylammonium bromide and benzyltrimethylammonium chloride. It is carried out at 70 ° C. to 140 ° C. under stirring in the presence of secondary amine hydrochlorides such as diethylammonium chloride; or phosphorus compounds such as triphenylphosphine. When amines are used, they can be extracted and removed by washing with an acidic aqueous solution after the reaction. By removing the amine, the storage stability of the product can be further improved.

The polymerizable composition obtained by the above method has high sensitivity to active energy rays such as ultraviolet rays and electron beams, and the cured coating film has various physical properties.
Although it is also suitable as a photo solder resist by itself, a composition obtained by mixing the polymerizable composition with an epoxy resin, a curing agent for an epoxy resin, a photopolymerization initiator and a diluent is also very suitable as a photo solder resist.

As the epoxy resin added to the above-mentioned polymerizable composition, cresol novolac epoxy resin, bisphenol A type epoxy resin and epoxy resin having an isocyanuric acid skeleton are preferable. Specific examples of the epoxy resin are as follows. Cresol novolac epoxy resin: Sumi Epoxy ESCN220HH manufactured by Sumitomo Chemical Co., Ltd., Epototo YDCN704, Epotote YDP manufactured by Tohto Kasei Co., Ltd.
N638, DEN-431, DEN made by Dow Chemical Company
-438 etc. Bisphenol A type epoxy resin: Epi-coat 828, Epi-coat 1001 of Yuka Shell Epoxy Co., Ltd., Epotote YD128 of Toto Kasei Co., Ltd., etc. Epoxy resin having isocyanuric acid skeleton: TEPIC manufactured by Nissan Kagaku Co., Ltd. The preferable amount of the epoxy resin used is the curable composition 1 described above.
It is 10 to 100 parts by weight per 00 parts by weight.

Examples of the curing agent for the epoxy resin include dicyandiamide, melamine, benzoguanamine, acetoguanamine, 2-methylimidazole and their derivatives. The amount of the curing agent used is appropriately 1 to 10 parts by weight per 100 parts by weight of the epoxy resin.

Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and other benzoins and alkyl ethers thereof; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy. 2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxyacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1
Acetophenones such as-[4- (methylthio) phenyl] -2-morpholino-propan-1-one; 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone And the like anthraquinones; 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4
Examples include thioxanthones such as diisopyrthioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone or xanthones. The photopolymerization initiators can be used alone or in combination of two or more. The preferred amount of the photopolymerization initiator used is 0.2 to 20 parts by weight, more preferably 1 to 1 per 100 parts by weight of the polymerizable composition.
0 parts by weight.

As the diluent, an organic solvent and / or a UV-curable monomer described below with reference to specific examples can be used. The preferable amount of the organic solvent used is 10 to 100 parts by weight, based on 100 parts by weight of the total amount of the polymerizable composition, the epoxy resin, the curing agent for the resin and the photopolymerization initiator, and the amount of the ultraviolet curable monomer. The preferred amount used is 10 to 20 parts by weight on the same basis. When the amount of the organic solvent used is less than 10 parts by weight, the viscosity of the obtained photo solder resist is too high and the coatability is easily impaired.
If it exceeds 100 parts by weight, the viscosity becomes low, and it becomes difficult to apply a three-roll roll as a kneading means.

Examples of the organic solvent include acetic acid esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, cellosolve, cellosolve acetate and cellosolve such as butyl cellosolve, and carbicarb. Examples thereof include carbitols such as Tol, carbitol acetate, butyl carbitol, and ethyl carbitol acetate, and preferably cellosolves or carbitols.

Examples of the UV-curable monomer include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; mono or di (meth) acrylate of ethylene glycol, Mono or di (meth) acrylates of glycols, such as mono (meth) acrylate of methoxyethylene glycol, mono or di (meth) acrylate of tetraethylene glycol, mono or di (meth) acrylate of tripropylene glycol; trimethylolpropane Examples include triol or tetraol (meth) acrylic acid adducts such as tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol tetra (meth) acrylate. That.

A photosolder resist comprising a polymerizable composition or a photosolder resist comprising a polymerizable composition, an epoxy resin, a curing agent for an epoxy resin, a photoinitiator and a diluent may further contain barium sulfate, if necessary.
Fillers such as silicon oxide, talc, clay and calcium carbonate, coloring pigments such as phthalocyanine blue, phthalocyanine green, titanium oxide and carbon black, various additives such as adhesion promoters and leveling agents, hydroquinone and hydroquinone monomethyl. ether,
Tertiary butyl catechol, phenothiazine, N-
A polymerization inhibitor such as nitrosophenylhydroxylamine aluminum salt may be added.

The present invention will be described more specifically below with reference to Examples and Comparative Examples.

[Example 1] 254 g (1.0 mol) of dipentaerythritol and 432 g of acrylic acid were placed in a flask equipped with a stirrer, a condenser and a water separator (Dean Stark trap).
(6.0 mol), 600 g of toluene, 12 g of p-toluenesulfonic acid and 0.12 g of hydroquinone were charged, and the mixture was heated and stirred to reflux the toluene.
0 g (5.0 mol) of water was removed from the system. 80 after cooling
0 g of 10% aqueous NaOH was poured and the mixture was stirred for 30 minutes. Then, the reaction solution was transferred to a separating funnel, the aqueous layer was separated and removed to remove excess acrylic acid, and a toluene solution of a dipentaerythritol derivative having 5 acryloyl groups and 1 hydroxyl group in one molecule was removed. Obtained.

The above toluene solution was transferred to a flask, and 74 g (0.5 mol) of phthalic anhydride and 6 g of triethylamine were added.
And 0.12 g of hydroquinone were added, and the mixture was stirred at 80 ° C. for 4 hours. After cooling, 580 g of a 10% ammonium sulfate aqueous solution was poured in, the mixture was stirred for 30 minutes, the reaction solution was transferred to a separating funnel, and the aqueous layer was removed. The oil layer was transferred to a flask and the solvent was distilled off under reduced pressure to obtain the polymerizable composition of the present invention. The acid value of the composition is 47 mgKOH
/ G. The obtained composition (hereinafter referred to as resin A-1) was added with 45 g of ethyl carbitol acetate to prepare a resin solution (640 g) having a solid content of 93% by weight. The above solution was used. The viscosity of this solution at 25 ° C. was 47,
It was 000 cps.

The following components are blended with the above resin A-1,
Composition for solder resist B-1 by kneading with three rolls
I got As the photopolymerization initiator, 2-methyl-1
-[4- (Methylthio) phenyl] -2-morpholino-propan-1-one (Ciba Geigy; trade name Irgacure 907) was used. Resin A-1 (as solid content) 100 parts Epoxy resin [TEPIC manufactured by Nissan Chemical Industries, Ltd.] 25 parts Epoxy resin [YDCN-704 manufactured by Tohto Kasei Co., Ltd.] 30 parts Melamine 2 parts Photopolymerization initiator 5 parts Ethylcarbi Tall acetate 15 parts Coloring pigment (phthalocyanine phosphorus) 1 part Calcium carbonate 30 parts Talc 10 parts Leveling agent 2 parts

The composition B-1 obtained was screen-printed on a copper glass epoxy substrate, a through-hole substrate and a printed wiring board on which a pattern was formed, and the composition B-1 was heated at 80 ° C. for 30 minutes.
Three kinds of test pieces were prepared by minute drying. Of these test pieces, a step tablet film was placed on the copper glass epoxy substrate, the through hole substrate was left as it was, and a resist pattern film was placed on the printed wiring board.
It was irradiated with 0 mJ / cm ² .

Then, after developing with a 1% sodium carbonate aqueous solution, it was heat-cured at 150 ° C. for 30 minutes. As a result, the photosensitivity of the copper glass epoxy substrate is 9 in the step tablet stage, the developability of the through-hole substrate is good and the holes are not filled, and the pencil hardness of the printed wiring board is 6H and the adhesion is also good. Met. Furthermore, regarding the cured coating film on the printed wiring board, a solder bath at 260 ° C.,
The durability against methylene chloride, 10% sodium hydroxide, 10% sulfuric acid and 10% hydrochloric acid was evaluated. The evaluation results are summarized in Tables 1 to 3.

[0026]

Examples 2 to 4 Resins A-2 to A-4 having the following acid values were synthesized by the same reaction as in Example 1, and further they were treated with other components in the same manner as the resin A-1 in Example 1. And solder resist compositions B-2 (Example 2) to B-
4 (Example 4) was obtained. Obtained compositions B-2 to B-4
Was measured for various physical properties in the same manner as the composition B-1 of Example 1, and the results are shown in Tables 1 to 3. Resin A-2: Resin having an acid value of 57 mgKOH / g (the unit is omitted below) obtained by reacting a dipentaerythritol derivative having 5.2 acryloyl groups and 0.8 hydroxyl groups with phthalic anhydride. (Combined with composition B-2).

Resin A-3: A resin having an acid value of 59 (composition B-3 obtained by reacting a dipentaerythritol derivative having 4.8 acryloyl groups and 1.2 hydroxyl groups with maleic anhydride. Blended with). Resin A-4: Resin having an acid value of 90 obtained by reacting a maleic anhydride with a dipentaerythritol derivative having 4.9 acryloyl groups and 1.1 hydroxyl groups (blended with composition B-4) .

[0028]

Comparative Examples 1 to 4 The following resins M-1 to M-4 were synthesized by the same reaction as in Example 1 and further mixed with other components to prepare a solder resist composition N-1 (Comparative Example 1). N-4
(Comparative example 4) was obtained. Physical properties of the compositions N-1 to N-4 are also shown in Tables 1 to 3. Resin M-1: Resin having an acid value of 120 obtained by reacting a dipentaerythritol derivative having 4.0 acryloyl groups and 2.0 hydroxyl groups with phthalic anhydride (blended with composition N-1) . Resin M-2: Resin having an acid value of 19 mg (composition N-, obtained by reacting maleic anhydride with a dipentaerythritol derivative having 5.8 acryloyl groups and 0.2 hydroxyl groups.
2).

Resin M-3: A dipentaerythritol derivative having 4.9 acryloyl groups and 1.1 hydroxyl groups and tetrahydrophthalic anhydride were reacted to obtain an acid value of 84.
Resin (blended with composition N-3). Resin M-4: Resin having an acid value of 74 obtained by reacting a pentaerythritol derivative having three acryloyl groups and one hydroxyl group with hexahydrophthalic anhydride (composition N-
4)).

[0030]

[Table 1]

Each physical property in Table 1 was evaluated by the following methods. a. Dryability: After coating the resist and drying at 80 ° C. for 30 minutes, the tack of the surface of the cured coating film was evaluated by touch with a finger. The results are indicated by the following symbols. ◎: No tack, ○: Slight tack,
Δ: There is tack, ×: There is noticeable tack. b. Photosensitivity ──── For the coating film coated on the copper glass epoxy substrate, Kodak Step Tablet No. Two
(21 steps) c. Developability ─── The through hole substrate was observed for hole filling after development. ◎: No hole filling at all, ○: Slight hole filling, △: 10 to 50% hole filling, ×:
A hole is filled. d. Pencil hardness: According to the hand scraping method in the test method of JISK-5400. e. Adhesion: According to JIS D-0202 test method (cross-cut test).

[0032]

[Table 2]

Evaluation of each physical property in Table 2 was carried out by the following methods. f. Solder heat resistance: According to the test method of JISC-6481, after repeating a 30-second float three times in a solder bath at 260 ° C, a peeling test was performed on the coating film with cellophane tape to observe the peeling of the coating film. ⊚: No peeling, ○: Slight peeling,
Δ: About 10% peeled off, ×: Whole peeled off.

G. Solvent resistance: The test piece was immersed in methylene chloride at 20 ° C. for 1 hour, and then a peeling test was performed on the coating film with cellophane tape to observe the peeling of the coating film. h. Chemical resistance: The test piece was immersed in each chemical solution at 20 ° C. for 1 hour, and then a peeling test was performed on the coating film with cellophane tape to observe the peeling of the coating film.

[0035]

[Table 3]

The insulation resistance in Table 3 is a value measured by the following measuring method. i. Insulation resistance --- According to JISZ-3197, insulation of test piece at room temperature (initial value), 55 ° C, 95%
RH, insulation after absorbing moisture for 96 hours (after moisture absorption) DC
Measured at -500V for 1 minute.

The insulation resistance of the solder resist cured coating film is
Usually, there is no problem if it is 1 × 10 ¹⁰ Ω or more. Therefore, as shown in Table 3, the solder resists of Examples 1 to 4 and Comparative Examples 1 to 4 are all at a sufficient level with respect to insulation resistance.

[0038]

INDUSTRIAL APPLICABILITY The polymerizable composition of the present invention can form a film with excellent adhesion to a substrate, has a high sensitivity to active energy rays, and an uncured film is easily soluble in an alkaline aqueous solution. Moreover, the cured film is excellent in hardness, adhesion, heat resistance, solvent resistance, chemical resistance and the like. Therefore, the photo solder resist comprising the polymerizable composition has an extremely excellent balance of physical properties as compared with the conventional photo solder resist.

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Claims (2)

[Claims] 1. A dipentaerythritol derivative having an average of 4.0 to 5.6 (meth) acryloyl groups and 0.4 to 2.0 hydroxyl groups in one molecule, and phthalic anhydride or maleic anhydride. The acid value obtained by reacting with an acid is 40 to 1
A photo solder resist comprising a polymerizable composition of 00 mg KOH / g. 2. A photo solder resist comprising the polymerizable composition according to claim 1, an epoxy resin, a curing agent for the epoxy resin, a photopolymerization initiator and a diluent as essential components.