JPH11255865A - Resin composition, resist ink composition for flexible printed circuit board and cured product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition excellent in flexibility, adherence, heat resistance and the like by admixing an epoxy group-containing thermoplastic elastomer, an aromatic glycidyl ether compound and a photo cation polymerization initiator. SOLUTION: There is provided a composition comprising 3-70 pts.wt. of an epoxy group-containing thermoplastic elastomer (A), 30-97 pts.wt. of an aromatic glycidyl ether compound (B), 0.01-30 pts.wt., based on 100 pts.wt. of (A+B), of a photo cation polymerization initiator (C) such as a diaryl iodonium salt and the like, further 0-50 wt.%, based on the component C, of a photosensitizer such as 9,10-phenylanthracene and the like, not more than 30 wt.%, based on (A+B+C), of an amine-based crosslinking agent, inorganic filler, a colorant and the like. This composition is coated to a thickness of 10-160 μm on a circuit board by the screen printing method or the like and dried to obtain a coated film, which is irradiated with ultraviolet rays with a negative film contacted directly therewith, and subsequently the unexposed part is immersed in a developer to effect development followed by heat treatment at 100-200 deg.C to obtain a printed circuit board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin composition, a resist ink composition for a flexible printed wiring board, and a cured product thereof.

[0002]

2. Description of the Related Art In recent years, ultraviolet curable compositions have been widely used in various fields for reasons such as resource saving, energy saving, workability improvement and productivity improvement. In the field of printed wiring board processing, for the same reason, various inks such as solder resist inks and marking inks have been transferred from conventional thermosetting compositions to ultraviolet curable compositions.
For example, JP-B-56-40329 discloses a reaction product of an epoxy resin-photopolymerizable α, β-unsaturated carboxylic acid addition product and a dibasic carboxylic anhydride, a photopolymerizable monomer and a photopolymerizable monomer. A curable photosensitive material containing a polymerization initiator is described. For a general printed wiring board called a rigid (hard) substrate, demand for high precision and high resolution has been increased for a solder resist in order to realize a high density with progress of electronics. Since the pattern accuracy cannot be obtained by the conventional screen printing method, a liquid photoresist method has been proposed, and 50% or more is currently introduced. Until now, when providing a protective layer on a flexible printed wiring board, a method of punching a polyimide film called a cover film with a mold that matches the pattern and then attaching it with an adhesive, or an ultraviolet-curing or thermosetting solder A method of applying a resist ink by a screen printing method is known.

[0003]

In the field of flexible printed wiring boards, higher densities have recently been required.
With conventional liquid photosolder resists, although pattern accuracy can be obtained, the coating is hard and the adhesion to polyimide is poor, so that sufficient flexibility and folding resistance cannot be obtained, and a certain degree of flexibility can be obtained. But poor workability and chemical resistance,
Heat resistance is insufficient, which is a problem.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, by using an epoxy group-containing thermoplastic elastomer, flexibility, folding resistance, adhesion, A resin composition excellent in chemical resistance, heat resistance and the like, which is suitable for a resist ink composition for a flexible printed wiring board, and a cured product thereof have been found. That is, the present invention

(1) A resin composition comprising an epoxy group-containing thermoplastic elastomer (A), an aromatic glycidyl ether compound (B) and a cationic photopolymerization initiator (C), (2) The resin composition according to (1), which is used for a resist ink for a flexible printed wiring board,
(3) a cured product of the resin composition according to (1) or (2),
(4) A cured product according to (3), which is a resist for a flexible printed wiring board, and (5) a flexible printed wiring board having a cured product layer according to (3) or (4).

As the epoxy group-containing thermoplastic elastomer (A) used in the present invention, for example, styrene and butadiene are copolymerized, and then the double bond in the copolymer is formed using an oxidizing agent such as peracetic acid. Those oxidized and epoxidized. This elastomer can be easily obtained from the market. For example, Epofriend (an epoxidized product of styrene, butadiene, and a styrene block copolymer) manufactured by Daicel Chemical Industries, Ltd. may be used.
Specifically, for example, Epofriend A1005 (butadiene / styrene weight ratio, 60/40, epoxy equivalent 180
0-2100), Epofriend A1010 (butadiene / styrene weight ratio, 60/40, epoxy equivalent 950-
1050), Epofriend A1020 (butadiene / styrene weight ratio 60/40, epoxy equivalent 480-54)
0) and so on.

The aromatic glycidyl ether compound (B) used in the present invention includes, for example, Epicoat 100
1, 1002, 1004 (all manufactured by Yuka Shell Epoxy Co., Ltd.), Epomic R-301, R-302, R-
Bisphenol A type epoxy resin such as No. 304 (all manufactured by Mitsui Petrochemical Industries, Ltd.), Epicoat 4001, 4
002, 4004 (both Yuka Shell Epoxy Co., Ltd.)
Bisphenol F type epoxy resin, the above-mentioned bisphenol A type epoxy resin or bisphenol F
A compound obtained by further reacting epichlorohydrin with a hydroxyl group in a molecule of a type epoxy resin to form a glycidyl ether, a bisphenyl-modified epoxy resin such as NC-3000P manufactured by Nippon Kayaku Co., Ltd., NC-7000, NC-7300 (all Naphthalene-modified epoxy resin such as Nippon Kayaku Co., Ltd., EPPN-201, EOCN by Nippon Kayaku Co., Ltd.
-102S, EOCN-103S, EOCN-104
Novolak-type epoxy resins such as S, EOCN-1020, BREN-S (all manufactured by Nippon Kayaku Co., Ltd.), YX-
Biphenol type epoxy resins such as 4000 and YL-6056 (both manufactured by Yuka Shell Epoxy Co., Ltd.) can be used. These aromatic glycidyl ether compounds (B) are used alone or in combination of two or more.

Examples of the cationic photopolymerization initiator (C) used in the present invention include diaryliodonium salts, triarylsulfonium salts, dialkylphenacylsulfonium salts, and dialkyl-4-hydroxyphenylsulfonium salts. Examples of the diaryliodonium salt include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrakispentafluorophenyl borate, and the like.

As the triarylsulfonium salt, for example, triarylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, 4,4'-bis [diphenylsulfonio]
Phenylsulfide-bis-hexafluoroantimonate, 4,4'-bis [diphenylsulfonio] phenylsulfide-bis-hexafluorophosphate,
4,4′-bis [di (β-hydroxyethoxy) phenylsulfonio] phenylsulfide-bis-hexafluoroantimonate, 7-di (p-toluyl) sulfonio-2-isopropyl-thioxanthone-hexafluoroantimonate, 7-di (p-toluyl) sulfonio-2-isopropyl-thioxanthone-hexafluorophosphate, 4-di (p-toluyl) sulfonio-4′-p-ter-butylphenylcabonyl-diphenylsulfide-hexafluoroantimonate,
4-di (p-toluyl) fluphonio-4'-p-te
r-butylphenylcarbonyl-diphenylsulfide-tetrakispentafluorophenyl borate and the like.

Examples of the dialkylphenacylsulfonium salt include dimethylphenacylsulfonium hexafluoroantimonate, diethylphenacylsulfonium hexafluorophosphate and the like.

The dialkyl-4-hydroxyphenylsulfonium salt includes, for example, dimethyl-4-hydroxyphenylsulfonium hexafluoroantimonate,
Diethyl-4-hydroxyphenylsulfonium hexafluorophosphate and the like.

The proportions of the components (A), (B) and (C) constituting the resin composition of the present invention are (A) +
When the total amount of (B) is 100 parts by weight, component (A) is preferably from 3 to 70 parts by weight, particularly preferably from 5 to 50 parts by weight, and component (B) from 30 to 97 parts by weight, in particular Preferably it is 50 to 95 parts by weight. The component (C)
(A) + (B) 100 parts by weight of the total amount, 0.01
To 30 parts by weight, particularly preferably 0.05 to 1 part by weight.
0 parts by weight.

The photosensitivity can be further improved by using a photosensitizer in combination with the cationic photopolymerization initiator (C) used in the present invention. As the photosensitizer, for example,
Phenothiazines including substituted phenothiazines, 2-ethyl-9,10-dimethoxyanthracene, 9,10-dichloroanthracene, 9,10-phenylanthracene, 1-chloroanthracene, 2-methylanthracene, 9-methylanthracene, 2-t -Butyl anthracene, anthracene, 1,2-benzanthracene,
1,2,3,4-dibenzanthracene, 1,2,5
6-dibenzanthracene, 1,2,7,8-dibenzanthracene, 9,10-dimethoxydimethylanthracene, perylene, pyrene, 9-fluorenone and the like. The use amount of the photosensitizer is preferably 0 to 50% by weight, particularly preferably 0.5 to 30% by weight, based on the cationic photopolymerization initiator (C).

In the resin composition of the present invention, it is preferable to further use an amine-based crosslinking agent such as melamine. Preferred amine-based crosslinking agents include, for example, melamine formaldehyde resin, benzoguanamine-formaldehyde resin, urea-formaldehyde resin and the like, and these can be used alone or in combination of two or more. Particularly suitable amine-based crosslinkers include, for example, Cymel 300, 301, 303, 350, 370, 38 for melamine formaldehyde resins.
And benzoguanamine-formaldehyde resins, for example, Cymel 1123 and 1125, and urea-formaldehyde resins, for example, beetles 60, 65, and 80 (all of which are American Cyanamid (American Cyanamid)).
anamid). Many other similar amine-based crosslinkers are commercially available.

Of the above amine-based crosslinking agents, melamines are more preferred, and melamine formaldehyde resins, ie, reaction products of melamine and formaldehyde, are particularly preferred. In these resins, the hydroxyl group is usually an alkyl ether, for example, ethers such as trialkylol melamine and hexaalkylol melamine. The alkyl group preferably has 1 to 8 carbon atoms, and more preferably a methyl group. The use amount of these crosslinking agents is preferably 30% by weight or less based on the total amount of the components (A), (B) and (C).

The resin composition of the present invention further has an adhesive property,
Barium sulfate, barium titanate, silicon oxide powder, finely divided silicon oxide, amorphous silica, talc, clay, magnesium carbonate, calcium carbonate, calcium oxide, aluminum oxide, mica powder for the purpose of improving properties such as hardness ,
Inorganic fillers such as aluminum hydroxide, antimony trioxide and barium borate can be used. The amount used is preferably from 0 to 60% by weight, particularly preferably from 0 to 40% by weight, in the composition of the present invention.

Further, if necessary, coloring agents such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black and naphthalene black, asbestos, orben, benton, montmorillonite and the like can be used. Various additives such as a thickener, an antifoaming agent such as a silicone type, a fluorine type and a polymer type, and / or an adhesion-imparting ion trapping agent such as a leveling agent and a silane coupling agent can be used. When these additives and the like are used, their use amounts are, for example, about 0.5 to 30% by weight in the composition of the present invention, respectively, but may be appropriately increased or decreased according to the purpose of use.

The resin composition of the present invention comprises the above (A)
Solvents which can dissolve the components (B) and (C), for example, ketones such as ethyl methyl ketone, methyl isobutyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene, dipropylene glycol dimethyl ether, dipropylene Glycol ethers such as propylene glycol diethyl ether, esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, carbitol acetate, propylene glycol monomethyl ether acetate, petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, solvent naphtha and other petroleum-based A uniform solution can be obtained by dissolving and mixing in a solvent, γ-butyrolactone, N-methyl-2-pyrrolidone, or the like.

The resin composition of the present invention can be obtained by blending the above-mentioned components preferably in the above-mentioned proportions and mixing them uniformly with a roll mill or the like. The resin composition of the present invention is usually liquid, but may be a dry film.

In order to produce a dry film, for example, a roll coater, a doctor bar, a wire bar method, a dipping method, a spin coating method, a gravure method, a doctor plate method, etc. are used on a base film (release film). After applying the resin composition of the present invention,
It can be obtained by drying in a drying oven set at 60 to 100 ° C. and removing a predetermined amount of solvent, and by attaching a release film or the like as necessary. On this occasion,
The thickness of the resist on the base film is 10 to 160 μm
m, preferably 20 to 60 μm. As the base film, polyethylene terephthalate,
A film such as polypropylene is preferably used.

The resin composition of the present invention comprises a resist ink,
Particularly, it is useful as a resist ink for a flexible printed wiring board, and can also be used as a paint, a coating agent, an adhesive and the like.

The cured product of the present invention is obtained by curing the above-mentioned resin composition of the present invention by irradiation with ultraviolet rays. The cured product of the resin composition of the present invention is used for an electric / electronic component such as a flexible printed wiring board having a through hole as a permanent resist.

The flexible printed wiring board of the present invention comprises:
It has a layer of a cured product of the above resin composition of the present invention. The thickness of the cured product layer is about 10 to 160 μm,
It is preferably about μm. This flexible printed wiring board can be obtained, for example, as follows. That is, when a liquid resin composition is used, a flexible printed wiring board substrate is screen-printed, sprayed, roll-coated, electrostatic-coated, curtain-coated by a method such as 10 to 160 μm in thickness. After applying the composition of the present invention and drying the coating film at 60 to 110 ° C., the negative film is brought into direct contact with the coating film (or placed on the coating film without contact), irradiated with ultraviolet light, After heating (for example, 60 to 100 ° C. × 1 to 30 minutes) as necessary, the unexposed portion is exposed to an appropriate developer, for example, by spraying, rocking and
Development is performed by a known method such as brushing or scrubbing. Then, if necessary, irradiate ultraviolet rays,
By performing the heat treatment at 00 to 200 ° C., a flexible printed wiring board having a permanent protective film satisfying various characteristics can be obtained.

Examples of the developing solution include alkoxyethanol having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, and the like.
Examples thereof include diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol dimethyl ether, carbitol acetate, propylene glycol monomethyl ether acetate, γ-butyrolactone, cyclohexanone, and N-methyl-2-pyrrolidone. These can be used alone or in combination of two or more. The temperature is 25 to 4
It can be adjusted arbitrarily between 5 ° C. Further, a small amount of a surfactant, an antifoaming agent or the like may be mixed in the developer. Water can be added to these developers in the range of 1 to 50% by volume for the purpose of preventing ignition.

When the flexible printed wiring board of the present invention is manufactured using a dry film, for example, the dry film from which the release film has been peeled off is transferred to the flexible printed wiring board substrate, and Exposure, development, and heat treatment may be performed.

[0026]

The present invention will be described more specifically below with reference to examples. Examples 1 to 3 and Comparative Examples 1 to 2 Each component was blended according to the blending composition (the numerical values are parts by weight) shown in Table 1 and kneaded with a three-roll mill to prepare a resin composition. This is printed on a flexible printed wiring board substrate (patterned copper-clad polyimide film substrate: copper thickness / 12 μm, polyimide film thickness / 25 μm).
m), the entire surface was coated by a screen printing method using a 100-mesh polyester screen so as to have a thickness of 20 to 30 μm, and the coating film was dried with a hot air drier at 80 ° C. for 3 hours.
Let dry for 0 minutes. Next, a negative film having a resist pattern was brought into close contact with the coating film and irradiated with ultraviolet rays (ultraviolet exposure apparatus: Oak Manufacturing Co., Ltd., model NMW-680).
GW, exposure amount 1000 mJ / cm ² ). Next, at 100 ° C
For 10 minutes, and spray-developed at 40 ° C. for 120 seconds with a developer consisting of N-methyl-2-pyrrolidone / water = 80/20 (volume ratio) to dissolve and remove unexposed portions. Thereafter, irradiation with ultraviolet rays of ² J / cm ² was performed, and further, heat treatment was performed at 150 ° C. for 40 minutes to obtain a flexible printed wiring board. The test piece having the obtained cured film was tested for adhesion, pencil hardness, dissolution resistance, acid resistance, heat resistance, bending resistance, and bending resistance as described below. Table 1 shows the results. In addition, the test method and the evaluation method are as follows.

(Adhesion) According to JIS K5400,
100 test pieces were made with a 1 mm-thick grain and subjected to a peeling test using cellophane tape. The state of peeling was evaluated by the following criteria.・ ・ ・: 100/100 without peeling. Δ: 50/100 to 99/100. X: 0/100 to 50/100.

(Pencil hardness) Evaluation was performed according to JIS K5400. (Solvent resistance) A test piece is immersed in an isopropyl alcohol solution at room temperature for 30 minutes. After confirming that there is no abnormality in the appearance,
A peeling test was performed using cellotape and evaluated according to the following criteria.・ ・ ・: No abnormality in the appearance of the coating film and no blistering or peeling. X: The coating film has blisters or peeling.

(Acid Resistance) A test piece is immersed in a 10% hydrochloric acid aqueous solution at room temperature for 30 minutes. After confirming that there is no abnormality in the appearance,
A peeling test was performed using cellotape and evaluated according to the following criteria.・ ・ ・: No abnormality in the appearance of the coating film and no blistering or peeling. X: The coating film has blisters or peeling.

(Heat Resistance) A rosin-based flux was applied to a test piece and immersed in a solder bath at 260 ° C. for 5 seconds. This was defined as one cycle, and three cycles were repeated. After allowing to cool to room temperature, a peeling test was performed using cellophane tape, and evaluated according to the following criteria.・ ・ ・: No abnormality in the appearance of the coating film and no blistering or peeling. X: The coating film has blisters or peeling.

(Bending resistance) The bending resistance was measured in accordance with JIS K5400. Using the test piece, the diameter of the mandrel was set to 2 mm, and the occurrence of cracks was observed. ○ ・ ・ ・ ・ No crack. ×: cracks occurred.

(Folding resistance) This was performed according to JIS C5016. The radius of curvature of the bent surface was 0.38 mm, and the number of times of bending until a crack was formed was measured.

[0033]

Table 1 Example 1 Comparative Example 1 2 3 12 (A) Component Epo Friend A1020 * 1 30 Epo Friend A1010 * 2 30 20 (B) Component Epicoat 1004 * 3 10 10 20 EPPN-201 * 4 20 40 NER * 5 30 30 60 (C) component KAYACURE PCI-615 * 6 10 10 10 10 10 Others hexamethoxymelamine 5.5 5 5.5 5 Silica (inorganic filler) 10 10 10 10 10 10 Phthalocyanine green (pigment) 0.5 0.5 0.5 0.5 0.5 Aerosil # 200 * 7 1.0 1.0 1.0 1.0 1.0 Modaflow * 8 1.0 1.0 1.0 1.0 1.0 Carbitol acetate 35 35 35 35 35 ────────────────────── ───────────── Adhesion ○ ○ ○ ○ ○ Pencil hardness 5H 5H 4H 6H 7H Flex resistance ○ ○ ○ × × Fold resistance 1000 times 1000 times 1000 times 1 time 1 time or more or more Solvent resistance ○ ○ ○ ○ ○ Acid resistance ○ ○ ○ ○ ○ Heat resistance ○ ○ ○ ○ ○

Note) * 1) Epofriend A1020: Epoxidized product of styrene-butadiene-styrene block copolymer, manufactured by Daicel Chemical Industries, Ltd. Butadiene / styrene weight ratio =
60/40, epoxy equivalent 480-540 * 2) Epofriend A1010: an epoxidized product of a styrene / butadiene / styrene block copolymer manufactured by Daicel Chemical Industries, Ltd. Butadiene / styrene weight ratio =
60/40, epoxy equivalent 950-1050. * 3) Epicoat 1004: Yuka Shell Epoxy Co., Ltd.
Bisphenol A type epoxy resin. * 4) EPPN-201: a phenol novolak type epoxy resin manufactured by Nippon Kayaku Co., Ltd. * 5) NER: Nippon Kayaku Co., Ltd. Epicoat 1001
(Bisphenol A type epoxy resin, manufactured by Yuka Shell Epoxy Co., Ltd.) A glycidyl ether obtained by reacting a hydroxyl group with epichlorohydrin. * 6) KAYACURE PCI-615: a cationic photopolymerization initiator manufactured by Nippon Kayaku Co., Ltd. 7-di (p-toluyl) sulfonio-2-isopropyl-thioxanthone-
Hexafluoroantimonate. * 7) Aerosil # 200: manufactured by Nippon Aerosil Co., Ltd.
Anhydrous silica. * 8) Modaflow: a leveling agent manufactured by Monsanto Co., Ltd.

As is clear from the evaluation results in Table 1, the cured product of the resist ink composition of the present invention is excellent in bending resistance and folding resistance, and has excellent adhesion, solvent resistance, acid resistance, heat resistance and the like. Clearly, it has satisfactory performance.

[0036]

The resin composition of the present invention can be developed in the formation of a solder resist pattern by exposing to ultraviolet light through a film on which a pattern has been formed, and developing the unexposed portions. It has excellent flex resistance, bending resistance, adhesiveness, pencil hardness, solvent resistance, acid resistance, heat resistance, etc., and is particularly suitable for liquid solder resist ink compositions for flexible printed wiring boards. ing.

Claims (5)

[Claims] 1. A resin composition comprising an epoxy-containing thermoplastic elastomer (A), an aromatic glycidyl ether compound (B) and a cationic photopolymerization initiator (C). 2. The resin composition according to claim 1, which is used as a resist ink for a flexible printed wiring board. 3. A cured product of the resin composition according to claim 1 or 2. 4. The cured product according to claim 3, which is a resist for a flexible printed wiring board. 5. A flexible printed wiring board having a layer of the cured product according to claim 3.