JPH0741716A - Solder resist ink resin composition - Google Patents

Abstract

PURPOSE:To obtain a solder resist ink resin compsn. which has a long pot life and an excellent workability and gives a cured film excellent in resistance to soldering heat, adhesion to a printed circuit board, and chemical resistance. CONSTITUTION:This ink resin compsn. contains a photopolymerizable unsatd. polycarboxylic acid resin (obtd. by reacting a novolak epoxy resin. an unsatd. monocarboxylic acid, and an org. polybasic acid anhydride), a photopolymn. initiator, tris(2,3-epoxypropyl) isocyanurate, and melamine cyanurate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder resist ink resin composition useful for producing a printed wiring board. In particular, the solder resist ink resin composition of the present invention has a long pot life and has excellent workability, and its cured film has excellent solder heat resistance, adhesion to a printed wiring board, and chemical resistance. .

[0002]

2. Description of the Related Art Solder resist ink is a paint for preventing the adhesion of solder by pre-applying it to a portion not requiring solder in a solder bath process and then curing it when a printed wiring board is prepared. For resist pattern formation of printed wiring boards, which require high resolution in recent years,
UV curable solder resist ink is used instead of the conventional thermosetting type. Since this ultraviolet-curable solder resist ink forms a pattern by exposure and development, problems such as bleeding and dripping that occur in the method of forming a pattern with a thermosetting ink do not occur. Among them, as a solder resist ink capable of alkali development, JP-A-61-243869 discloses a curable resin obtained by reacting a carboxyl group-containing novolac type epoxy compound with an acid anhydride and a photopolymerization initiator. The following ink composition is disclosed. Also, Japanese Patent Laid-Open No. 4-165
No. 357, an ink composition comprising a curable resin obtained by reacting a carboxyl group-containing novolac type epoxy compound with an acid anhydride, a photopolymerization initiator, a heterocyclic epoxy resin, and an amine compound. It is disclosed.

However, even if the ink composition described above is used, sufficient performance such as heat resistance, adhesion to a printed wiring board and chemical resistance cannot be obtained. In addition, the solder resist ink resin composition that requires high resolution,
By making the epoxy compound and the curing agent uniform in the composition, a fine resist pattern can be formed. Hitherto, imidazoles, melamine, dicyandiamide and the like have been known as curing agents for epoxy compounds. Imidazoles have a short pot life when used as a solder resist ink resin composition, while melamine and dicyandiamide have a long pot life, but it is difficult to obtain fine powders of these melamine and dicyandiamide. The process of producing the solder resist ink resin composition using the agent requires a long time using a kneading machine such as a three-roll machine, and thus has a problem in workability.

[0004]

SUMMARY OF THE INVENTION The present invention provides a combination of a specific epoxy compound and a specific curing agent,
It is intended to obtain a solder resist ink composition which is excellent in solder heat resistance, adhesion to a printed wiring board, and chemical resistance and is stable for a long time by a simple method in a short time.

[0005]

The solder resist ink resin composition of the present invention comprises a novolac type epoxy resin and
A photopolymerizable unsaturated group-containing polycarboxylic acid resin (A) obtained by reacting an unsaturated monocarboxylic acid with an anhydride of an organic polybasic acid, a photopolymerization initiator (B), and tris (2,3- It is characterized by containing epoxypropyl) isocyanurate (C) and melamine cyanurate (D).

The photopolymerizable unsaturated group-containing polycarboxylic acid resin which is the component (A) used in the present invention is a reaction of a novolac type epoxy resin, an unsaturated monocarboxylic acid, and an anhydride of an organic polybasic acid. It is not particularly limited as long as it is obtained by the reaction, but preferably, a novolac type epoxy resin and an unsaturated monocarboxylic acid are reacted with each other, and an anhydride of an organic polybasic acid is added to the obtained product. It is good to react.

Examples of the novolac type epoxy resin include phenol novolac type epoxy resin and cresol novolac type epoxy resin. These can be used alone or in combination. Examples of unsaturated monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid,
Examples thereof include cinnamic acid, and one or more of these can be used.

The reaction between the novolac type epoxy resin and the unsaturated monocarboxylic acid is carried out by adding 0.5 to 1 mol of the unsaturated monocarboxylic acid to 1 mol of the epoxy group of the novolac type epoxy resin.
It is preferable to react at a ratio of 1.0 mol. At this time, it is preferable to add a tertiary amine or phosphine as a catalyst in an amount of 0.1 to 10% by weight based on the total weight of the novolac type epoxy resin and the unsaturated monocarboxylic acid. Examples of the tertiary amine include triethylamine and 2-ethyl-4-methylimidazole, and examples of the phosphine include triphenylphosphine and triphenylphosphine benzyl bromide. The reaction temperature can be 80 to 120 ° C., and the reaction time is 10 to 50 hours. The solvent used in this reaction is preferably cellosolves or glymes, and examples thereof include ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, and diethylene glycol dimethyl ether.

Examples of the organic polybasic acid anhydrides include saturated polybasic acid anhydrides and unsaturated polybasic acid anhydrides. For example, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, Examples thereof include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, maleic anhydride, succinic anhydride, and itaconic anhydride, and one or more of these may be used. The anhydride of the organic polybasic acid is 0.1 mol or more, preferably 1 mol, relative to 1 mol of the hydroxyl group of the reaction product generated by the reaction of the novolac type epoxy resin and the unsaturated monocarboxylic acid.
It is preferable to react at a ratio of 0.2 to 1.0 mol. The reaction temperature can be 60 to 150 ° C., and the reaction time can be 5 to 20 hours.

The photopolymerizable unsaturated group-containing polycarboxylic acid resin can be used in a concentration of 30 to 90% by weight as a solid content of the resin. As the photopolymerization initiator which is the component (B) used in the present invention, known ones can be used, and examples thereof include benzoin, benzoin ethyl ether, benzophenone and acetophenone. The above photopolymerization initiator can be used as a powder or as a solution. Examples of the solvent include ethyl acetate, methyl acetate, methyl ethyl ketone and the like.

The component (C) used in the present invention, tris (2,3-epoxypropyl) isocyanurate, can be used in the form of fine powder. The particle size is 10 μm
Hereafter, it is usually possible to use the one pulverized to 0.1 to 8 μm. This is because the curing reaction of the solder resist ink resin composition of the present invention is carried out uniformly by dispersing it in the form of fine powder. Tris (2,3-epoxypropyl) isocyanurate used in the present invention is, for example, manufactured by Nissan Chemical Industries, Ltd., trade name TEPIC-S.
(Particle size 1 to 200 μm), TEPIC-L (particle size 1
~ 200 μm), TEPIC-H (particle size 10-400)
μm), TEPIC-SP (average particle size 3 to 4 μm), and the like, and these can be added in the particle size as they are or further pulverized and used.

Melamine cyanurate which is the component (D) used in the present invention acts as a curing agent for tris (2,3-epoxypropyl) isocyanurate. Melamine cyanurate is a salt obtained by the equimolar reaction of melamine with cyanuric acid or isocyanuric acid. Melamine cyanurate used as a curing agent is
In order to uniformly carry out the curing reaction of the solder resist ink resin composition of the present invention, it is desirable to add it in the form of fine powder.
The particle size is 8 μm or less, preferably 0.1
Is about 4 μm. For example, manufactured by Nissan Chemical Industries, Ltd., trade name MC-640 (average particle size of primary particles, 1-2 μm)
Can be used.

The melamine cyanurate as the component (D) is pulverized to a desired particle size before being mixed with the components (A), (B) and (C) and mixed to obtain the solder resist ink resin composition of the present invention. Although it can be a thing, (A),
It is preferable that the components (B) and (C) and the component (D), melamine cyanurate, be mixed to form the solder resist ink resin composition of the present invention, and then finely pulverized. This crushing is performed by a kneading machine such as a three-roll mill.

The preferred blending ratio of the solder resist ink resin composition of the present invention is 100 parts by weight of the resin solid content of the photopolymerizable unsaturated group-containing polycarboxylic acid resin which is the component (A), and the component (B). 0.5 to 20 parts by weight, preferably 1 to 10 parts by weight as a solid content of the photopolymerization initiator of
The component (C), tris (2,3-epoxypropyl) isocyanurate, as solid content, 5 to 90 parts by weight, preferably 10 to 70 parts by weight, and the component (D), melamine cyanurate, as solid content 5 It is advisable to add it in an amount of ˜100 parts by weight, preferably 10-70 parts by weight.

Inorganic fine particles may be added as an optional component to the solder resist ink resin composition of the present invention. Examples of the inorganic fine particles include talc, silica, calcium carbonate, kaolin and the like. As its particle size,
What was crushed to 8 μm or less can be used. More preferably, it is ground to 0.1 to 4 μm. The solder resist ink resin composition of the present invention can contain cellosolves and glymes as a solvent.
Examples thereof include ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, diethylene glycol dimethyl ether, and unsaturated group-containing monomers such as methyl methacrylate. By adding these solvents, it can be used at a concentration of 60 to 95% by weight.

The solder resist ink resin composition of the present invention has a film thickness of 10 to 100 μm on a printed board by a screen printing method, a curtain coating method, a spray coating method, a roll coating method, a spin coating method, a dip coating method or the like. It can be applied.

[0017]

[Function] In order to form a fine resist pattern,
The solder resist ink resin composition requires an epoxy compound and a curing agent to be uniform in the composition, but melamine and dicyandiamide that are commonly available are
The average particle size of the primary particles is 5 μm or more, and a fine pulverization step is indispensable for carrying out a uniform curing reaction. On the other hand, since melamine cyanurate is produced by a liquid-liquid reaction of melamine and cyanuric acid, it can be obtained as a fine powder, and the average particle size of primary particles is usually 2 μm or less. Therefore, the work of re-pulverization can be reduced.

Melamine cyanurate has a heating loss temperature higher by about 50 to 80 ° C. than melamine. The decomposition initiation temperature of melamine measured in an air stream is 270 ° C, while that of melamine cyanurate is 340 ° C. Therefore,
When melamine is used as a curing agent, when unreacted melamine is present, blistering occurs on the surface of the cured resin composition during immersion in a solder bath, but when melamine cyanurate is used as a curing agent, Even if the reaction melamine cyanurate is present, the blistering phenomenon does not occur on the surface of the cured resin composition.

In the photopolymerizable unsaturated group-containing polycarboxylic acid resin of the component (A) used in the present invention, the reaction between the novolac type epoxy resin and the unsaturated carboxylic acid is based on 1 mol of the epoxy group of the novolac type epoxy resin. When the unsaturated carboxylic acid exceeds 1.0 mol, the unreacted unsaturated carboxylic acid remains, so that the heat resistance and chemical resistance decrease, and when it is less than 0.5 mol, It is not preferable because the photopolymerizability is insufficient. Furthermore, the reaction between the reaction product of the novolac type epoxy resin and the unsaturated carboxylic acid and the anhydride of the organic polybasic acid is carried out by adding 1 mol of the hydroxyl group of the product of the reaction between the novolac type epoxy resin and the unsaturated carboxylic acid. On the other hand, when the organic polybasic acid anhydride exceeds 1 mol,
Since the unreacted anhydride of organic polybasic acid remains, heat resistance,
If the chemical resistance is lowered and the amount is less than 0.1 mol, the alkali developability is insufficient, which is not preferable.

In the solder resist ink resin composition of the present invention, based on 100 parts by weight of the resin solid content of the photopolymerizable unsaturated group-containing polycarboxylic acid resin which is the component (A),
When the amount of the photopolymerization initiator as the component (B) exceeds 20 parts by weight, heat resistance and chemical resistance are adversely affected, and when it is less than 0.5 parts by weight, the photopolymerizability is insufficient, which is preferable. Furthermore, if the tris (2,3-epoxypropyl) isocyanurate of the component (C) exceeds 90 parts by weight, the photopolymerizability is insufficient, and if it is less than 5 parts by weight,
It is not preferable because the thermosetting property is insufficient, and (D)
When the melamine cyanurate of the component exceeds 100 parts by weight, the curing performance cannot be expected further for the added amount,
If it is less than 5 parts by weight, the hardness is insufficient, which is not preferable.

[0021]

【Example】

Example 1 1% by weight of triethylamine and 0.1% by weight of hydroquinone were added to 1 equivalent of a phenol novolac type epoxy resin [trade name Epicoat 154, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 180], and acrylic acid 1 An equivalent amount was reacted at 90 ° C. for 20 hours, and 0.5 equivalent of phthalic anhydride was reacted at 80 ° C. for 10 hours to obtain an epoxy acrylate resin.

100 parts by weight of this epoxy acrylate resin as a resin solid content, and benzoin ethyl ether 5
Parts by weight and tris (2,3-epoxypropyl) isocyanurate [manufactured by Nissan Chemical Industries, Ltd., trade name TEPIC
-SP, epoxy equivalent 100, average particle diameter 3-4 μm]
50 parts by weight, melamine cyanurate [manufactured by Nissan Chemical Industries, Ltd., trade name MC-640, average particle size of primary particles 1 to 2 μm] 50 parts by weight, ethyl cellosolve 100 parts by weight, and ground talc [ 50 parts by weight of particle diameter of 2 to 5 μm] was mixed and kneaded once with a three-roll to obtain a solder resist ink resin composition of the present invention.

After applying the solder resist ink resin composition of the present invention to a copper-clad laminate with a bar coater, 7
It was dried at 0 ° C. for 30 minutes to obtain a cured film of about 25 μm.
Place a mask film on top of this and use a high pressure mercury lamp to
Exposure was performed at an irradiation intensity of mW / cm ² . Then, at 23 ° C. with an alkaline developer composed of a 1% by weight aqueous solution of sodium carbonate.
After development for 1 minute, a solder resist pattern was obtained. Further, a cured coating was obtained by curing at 150 ° C. for 2 hours using an oven furnace.

Comparative Example 1 Example 1 was repeated except that 50 parts by weight of melamine cyanurate was replaced with 7.5 parts by weight of 2-ethyl-4-methylimidazole (manufactured by Shikoku Chemicals Co., Ltd.). In the same manner as described above, kneading was performed once using a triple roll to obtain a solder resist ink resin composition.

This solder resist ink resin composition was applied to a copper-clad laminate with a bar coater, and then 70
It was dried at 30 ° C. for 30 minutes to obtain a cured film of about 25 μm. Place a mask film on top of this and use a high pressure mercury lamp for 1.5m
Exposure was performed at an irradiation intensity of W / cm ² . Then, by developing with an alkali developing solution consisting of a 1 wt% aqueous solution of sodium carbonate at 23 ° C. for 1 minute, a solder resist pattern was obtained. Furthermore, using an oven furnace,
A cured film was obtained by curing for a time.

Comparative Example 2 In Example 1, 50 parts by weight of melamine cyanurate was mixed with ground melamine [manufactured by Nissan Chemical Industries, Ltd., trade name EG.
Melamine, average particle diameter of primary particles 5 μm] The procedure was performed in the same manner as in Example 1 except that the amount was changed to 25 parts by weight, but the solder resist ink resin composition was prepared by kneading 4 times using 3 rolls. Obtained.

This solder resist ink resin composition was applied to a copper clad laminate with a bar coater, and then 70
It was dried at 30 ° C. for 30 minutes to obtain a cured film of about 25 μm. Place a mask film on top of this and use a high pressure mercury lamp for 1.5m
Exposure was performed at an irradiation intensity of W / cm ² . Then, by developing with an alkali developing solution consisting of a 1 wt% aqueous solution of sodium carbonate at 23 ° C. for 1 minute, a solder resist pattern was obtained. Furthermore, using an oven furnace,
A cured film was obtained by curing for a time.

The solder resist ink resin composition and the cured product of the solder resist ink resin composition after exposure, development and heat curing were evaluated according to the following test methods. Storage stability test The above solder resist ink resin composition was sealed in a container and stored at 60 ° C, and the number of days until gelation was measured.

Solder heat resistance test Two cured products of the solder resist ink resin composition
After dipping in a molten solder bath at 80 ° C. for 2 minutes, blisters and peeling on the surface of the cured product were visually observed. O indicates that the surface of the cured product is normal, and Δ indicates that blister or peeling has occurred in the area of more than 0% and less than 10% of the surface of the cured product, and in the area of 10% or more of the surface of the cured product. Those that caused blistering or peeling were indicated by a cross.

Acid resistance test Two cured products of the solder resist ink resin composition
After dipping for 15 minutes in a 10 wt% sulfuric acid aqueous solution kept at 3 ° C., the appearance of the coating film was visually observed. If there is no abnormality on the surface of the cured product, it is marked with ◯. Those that are awake are indicated by a cross.

Alkali resistance test Two cured products of the above solder resist ink resin composition
After dipping for 15 minutes in an aqueous solution of 10 wt% caustic soda kept at 3 ° C., the appearance of the coating film was visually observed. If there is no abnormality on the surface of the cured product, it is indicated by a circle.
Those having blisters in the area less than 1 are indicated by Δ, and those having blisters in an area of 10% or more of the surface of the cured product are indicated by x.

Adhesion Test A cross-cut adhesion test was conducted according to JIS-D0202. 100 pieces of 1 mm grids (10 pieces x 10 pieces) on the surface of the cured product of the solder resist ink resin composition
After making, a cellophane adhesive tape was completely adhered on the grid, and immediately one end of the tape was kept perpendicular to the coating surface, momentarily separated, and the number of grids left without being completely peeled off was checked. When the number of remaining grids is 100, it is marked with a circle, and when the number of grids remaining is 99 to 98, it is marked with a triangle.
When the number of remaining grids was 97 or less, it was marked with x.

Pencil hardness test A pencil scratch test was conducted according to JIS-K5400. Pencils having different hardness from 9H to 6B were prepared.
The cured product of the solder resist ink resin composition is fixed on a horizontal table with the coating surface facing upward, and a pencil is held at an angle of about 45 degrees. The coated surface was scratched by extruding at a constant speed (about 1 cm / s). Sharpen the pencil tip every time you scratch it,
A test is conducted 5 times with pencils having the same density code, and a group in which the scratches on the coated surface are 2 times or more and less than 2 times is obtained, and the density code of the pencil which is less than 2 times is the solder resist ink resin composition. The pencil scratch value of the cured product.

The test results are shown in Table 1. Table 1 Example 1 Comparative example 1 Comparative example 2 Roll kneading time 5 minutes 5 minutes 20 minutes Storage stability 30 days or more 20 days 30 days or more Solder heat resistance ○ △ △ Acid resistance ○ △ ○ Alkali resistance ○ △ ○ Adhesion ○ Δ ○ Pencil hardness 7H 5H 7H As can be seen from Table 1 above, the solder resist ink resin composition of the present invention using the melamine cyanurate of Example 1 as a curing agent was the 2-ethyl-4-methyl of Comparative Example 1. Compared to the solder resist ink resin composition using imidazole as a curing agent, it has excellent storage stability, and the cured product has excellent heat resistance, chemical resistance, adhesion and hardness when immersed in a solder bath. is there. Further, the laminated plate does not cause discoloration or the like. Further, the solder resist ink resin composition of the present invention can shorten the roll kneading time and significantly shorten the manufacturing process as compared with the solder resist ink resin composition of Comparative Example 2 using melamine as a curing agent. In addition, the cured product can form an extremely excellent solder resist pattern without causing blistering or peeling of the surface of the cured product even when immersed in a solder bath.

[0035]

INDUSTRIAL APPLICABILITY The solder resist ink resin composition of the present invention can be manufactured by a simple process in a short time, and since it has a long pot life, it can be used stably for a long period of time. Further, the cured product is excellent in heat resistance, adhesiveness, chemical resistance, particularly heat resistance when immersed in a solder bath, so that it may exhibit excellent performance in resist pattern formation of a printed wiring board that requires high resolution. I can.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H05K 3/28 D 7128-4E

Claims (1)

[Claims] 1. A photopolymerizable unsaturated group-containing polycarboxylic acid resin (A) obtained by reacting a novolac type epoxy resin, an unsaturated monocarboxylic acid, and an anhydride of an organic polybasic acid, and photopolymerization initiation. A solder resist ink resin composition comprising an agent (B), tris (2,3-epoxypropyl) isocyanurate (C) and melamine cyanurate (D).