JP2934098B2 - Photosensitive resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin composition, and more particularly, to heat resistance, moisture resistance, electrical insulation, chemical resistance, and flexibility capable of forming an image by exposure to ultraviolet light and development with a dilute alkaline aqueous solution. The present invention relates to a photosensitive resin composition used for a solder resist for manufacturing a printed wiring board having excellent properties.

[0002]

2. Description of the Related Art In a printed wiring board, a solder resist is widely used as a permanent protective film for a conductor circuit. Solder resist is a film that is formed on the entire surface except for the parts where the circuit conductors are soldered.When soldering electronic components to printed wiring boards, it prevents solder from adhering to unnecessary parts and In addition, it also functions as a protective film for preventing the circuit conductor from being directly exposed to air and corroded by oxidation or humidity. Conventionally, it has been the mainstream that a solder resist is patterned on a substrate by a screen printing method and cured by ultraviolet light or heat. On the other hand, with the recent demand for higher wiring density of printed wiring boards, solder resists are also required to have higher resolution and higher precision, regardless of whether they are consumer boards or industrial boards. There has been proposed a liquid photo-solder resist method which is excellent in the coating property. For example, Japanese Patent Laid-Open No. 50-144431
And JP-A-51-40451 disclose a solder resist composition comprising a bisphenol type epoxy acrylate, a sensitizer, an epoxy compound, an epoxy curing agent and the like. For these solder resists, a liquid composition, which is a photosensitive resin composition, is applied on the entire surface of a printed wiring board, and after evaporating the solvent, exposure is performed, and unexposed portions are removed using an organic solvent and developed. However, the removal (development) of the unexposed portion with the organic solvent involves a problem that there is a danger of environmental pollution and fire since the organic solvent is used in a large amount. In particular, the problem of environmental pollution has a great deal of recent influence on the human body.

In order to solve this problem, there has been proposed an alkali development type photo solder resist which can be developed with a dilute aqueous alkali solution. JP-A-56-40329 and JP-A-57-45785 as an alkali-developable ultraviolet curable material.A reaction product obtained by reacting an unsaturated monocarboxylic acid with an epoxy resin and further adding a polybasic anhydride. Is disclosed as a base polymer. Japanese Patent Publication No. 1-54390 discloses an active energy ray-curable resin obtained by reacting a reaction product of a novolak type epoxy resin with an unsaturated monocarboxylic acid and a saturated or unsaturated polybasic acid anhydride. A photocurable liquid resist ink composition that can be developed with a dilute aqueous alkali solution containing a polymerization initiator is disclosed.

[0004]

The liquid solder resist inks disclosed in the above publications or currently marketed can be developed with a dilute alkaline aqueous solution by introducing a carboxyl group into epoxy acrylate. Properties and chemical resistance are poor, and heat shrinkage due to post cure is large, which causes cracks in the coating film. The present invention provides a photosensitive resin composition free from such problems.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that an organosilicone compound having a radical-reactive unsaturated bond in the molecule and a polyfunctional epoxy compound have been developed. This unreacted epoxy group is further added to a silicone-modified epoxy resin obtained by reacting an epoxy resin having an unsaturated bond in a molecule obtained by reacting a part of the epoxy group of the resin with (meth) acrylic acid. 1 / 0.8-1.2 by equivalent ratio with (meth) acrylic acid
Further, a polybasic anhydride is added in an equivalent ratio of 1 to the hydroxyl group of the silicone-modified epoxy acrylate, which is the product.
A photosensitive resin composition characterized by containing a reaction product of 0.3 / 1.0, a photopolymerization initiator, a reactive diluent, and a thermosetting compound.

The component a) used in the composition of the present invention is a polyfunctional epoxy resin having an epoxy equivalent of usually 1,000 or less, preferably 100 to 500, such as a phenol novolak epoxy resin, a cresol novolak epoxy resin, a glycidylamine type. Some of epoxy groups such as polyfunctional epoxy resin, bisphenol S-modified novolak type polyfunctional epoxy resin, polyfunctional modified novolak type epoxy resin, and epoxy resin condensate of phenols and aromatic aldehyde having phenolic hydroxyl group ( React with (meth) acrylic acid. In this case, the multifunctional epoxy resin and (meth)
Acrylic acid is usually 1 / 0.01 to 0.
5, particularly preferably from 1 / 0.02 to 0.2 is preferred, since it prevents gelation during the reaction with the polymerizable silicone compound.

The thus obtained epoxy resin having an unsaturated bond reacts with an organic silicone compound having a radical-reactive double bond in the molecule. As this organosilicone compound having a radical-reactive double bond, any of this kind of organosilicone compound can be used, and for example, a silicone acrylate represented by Chemical Formula 2, a vinyl-modified silicone represented by Chemical Formula 3, and the like are typical. No.

[0008]

Embedded image (In the formula, R ₅ represents a hydrogen atom or a methyl group.)

[0009]

Embedded image (Where n is the number of polymerizations)

The above-mentioned reaction between the epoxy resin having an unsaturated bond and the organosilicone compound having a radical-reactive double bond in the molecule is carried out by reacting both with a radical polymerizable initiator such as hydroperoxide or peroxyester. A known radical polymerization initiator such as peroxide and azobisisobutyronitrile is added at 0.05 to 1.0% based on the resin content and reacted at 80 to 120 ° C. for 3 to 10 hours to obtain a silicone-modified polyfunctional epoxy resin. Can be

The unreacted epoxy group of the silicone-modified polyfunctional epoxy resin thus obtained is (meth)
Acrylic acid is reacted under reflux using a solvent such as carbitol acetate, for example, and 1 / 0.8 to 1.2 is added at an equivalent ratio. This addition renders the resin photosensitive. Then, maleic anhydride, succinic anhydride, phthalic anhydride, trimellitic anhydride, hexahydrophthalic anhydride, and hexahydrophthalic anhydride are added to the hydroxyl groups of the epoxy acrylate of the silicone-modified epoxy resin so that the epoxy resin can be developed with a dilute aqueous alkali solution. -Methylhexahydrophthalic acid, 4-methylhexahydrophthalic anhydride, 3-ethylhexahydrophthalic anhydride, 4-ethylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, 4-methyl anhydride Polybasic anhydrides such as methyltetrahydrophthalic acid, 3-ethyltetrahydrophthalic anhydride, and 4-ethyltetrahydrophthalic anhydride are used in an equivalent ratio of 1 / 0.3 to
The reaction is carried out under 1.0 reflux to obtain the component a) of the composition of the present invention.

The photopolymerization initiator b) used in the present invention comprises:
Commonly used photopolymerization initiators are used. Representative examples include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, , 2-Diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1- [4- (methylthio) phenyl]
-2-morpholino-propan-1-one, benzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methyl Thioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4 diethylthioxanthone, benzyldimethylketal, acetophenonedimethylketal, P-dimethylaminobenzoic acid ethyl ester and the like. They can be used in combination. A suitable use amount of the above photopolymerization initiator is 0.5 to 50 parts by weight, preferably 2.0 to 30 parts by weight, based on 100 parts by weight of the reactive product.

The reactive diluent c) used in the present invention is used to further enhance the photocuring of the reaction product to obtain a coating film having acid resistance, heat resistance, alkali resistance and the like. A compound having at least two or more double bonds. Representative examples of the reactive diluent include, for example,
1,4-butanediol di (meth) acrylate, 1,6-
Hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, neopentyl glycol di (meth) acrylate hydroxypivalate, dicyclopentane Nildi (meth) acrylate, caprolactone-modified dicyclopentenyldi (meth) acrylate, EO-modified di (meth) acrylate phosphate, allylated cyclohexyldi (meth) acrylate, isocyanurate di (meth) acrylate, trimethylolpropanetri (meth) acrylate ) Acrylate, dipentaerythritol tri (meth) acrylate, propionic acid-modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate A) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, propionic acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa And reactive diluents such as (meth) acrylates.
The difunctional, difunctional, tetrafunctional, pentafunctional, and hexafunctional polyfunctional reactive diluents can be used either individually or in a mixed system. A suitable amount of the reactive diluent is 2.0 to 40 parts by weight, preferably to the reaction product.
4.0 to 20 parts by weight. If the addition amount is less than 2.0 parts by weight, sufficient photocuring cannot be obtained, and the cured film cannot have sufficient properties such as acid resistance and heat resistance.If the addition amount exceeds 40 parts by weight, the tack becomes severe, At the time of exposure, the artwork film adheres to the substrate, making it difficult to obtain a desired cured coating film.

The thermosetting compound used in the present invention is typically a compound represented by the general formula (1). Examples of this thermosetting compound include biphenyl-4,4'-diglycidyl ether, 3,3'-dimethylbiphenyl-4,4 '
-Diglycidyl ether, 3,5'-dimethylbiphenyl-
4,4'-diglycidyl ether and 3,3 ', 5,5'-tetramethylbiphenyl-4,4'-diglycidyl ether. Particularly preferred among them are biphenyl-4,4'-diglycidyl ether and 3,3 ', 5,5'
-Tetramethylbiphenyl-4,4'-diglycidyl ether. Further, by using a known epoxy curing accelerator such as a melamine compound, an imidazole compound, and a phenol compound as a reaction accelerator in combination, and post-curing the coating film, the resulting resist film has heat resistance, moisture resistance, electric insulation, Various properties such as chemical resistance, adhesion, flexibility, and hardness can be improved, and it is useful as a solder resist for printed wiring boards.

The photosensitive resin composition of the present invention comprises a reaction product obtained by converting the remaining epoxy group of a silicone-modified epoxy resin into an acrylate and then carboxy-modifying with a polybasic anhydride.
It is composed of a photopolymerization initiator, a reactive diluent, and a thermosetting compound.If necessary, various additives, for example, silica, alumina, talc, calcium carbonate, inorganic pigments such as barium sulfate, phthalocyanine-based And azo-based organic pigments, paint additives such as antifoaming agents and leveling agents, and the like.

The above-described photosensitive resin composition of the present invention is applied to a substrate at a desired thickness, and then heated at 60 to 80 ° C. for 15 to 60 minutes to volatilize the organic solvent. After the negative film of the pattern is brought into close contact with the film and irradiated with ultraviolet light from above, the non-exposed area is removed with a dilute aqueous alkaline solution to develop the coating film. The dilute aqueous alkali solution used here is generally a 0.5 to 5% by weight aqueous sodium carbonate solution, but other alkalis can also be used. Then, the target resist film can be formed by performing post-curing for 30 minutes in a hot air circulation type dryer at 150 ° C. Next, examples will be given in order to more specifically explain the present invention, and effects showing that the present invention is excellent will be shown in comparison with a photosensitive resin composition lacking the requirements of the present invention. In the examples, “parts” and “%” are “parts by weight” and “% by weight”.

[0017]

【Example】

Synthesis Example 1 Cresol novolak type epoxy resin (epoxy equivalent 21
0) 6 parts of acrylic acid were added to 194 parts of carbitol acetate 11
The reaction was carried out under reflux using 0 parts as a solvent to obtain an epoxy resin having an unsaturated bond. Then this epoxy resin 310
Silicone compound in part 4

Embedded image 50 parts were added and reacted in the presence of a radical polymerizable initiator to obtain a silicone-modified epoxy resin having an epoxy equivalent of 305. 72 parts of acrylic acid was reacted with 305 parts of the silicone-modified epoxy resin under reflux with 60 parts of carbitol acetate to obtain a silicone-modified cresol novolac epoxy acrylate. Further, 76 parts of hexahydrophthalic anhydride was added to this epoxy acrylate and reacted under reflux until the acid value reached the theoretical value to obtain a photosensitive resin having a solid content of 70%.

Synthesis Example 2 A photosensitive resin having a solid content of 70% was obtained in the same manner as in Synthesis Example 1 except that a normal cresol novolak type epoxy resin was used instead of the silicone-modified cresol novolak type epoxy resin in Synthesis Example 1. .

Example 1 To 100 parts of the photosensitive resin obtained in Synthesis Example 1, 8.0 parts of benzyldiethyl ketal, 8.0 parts of trimethylolpropane triacrylate, 8.0 parts of biphenyl-4,4'-diglycidyl ether, 0.5 part of phthalocyanine green 0.5 Department, talc 8.0
The parts were mixed and dispersed with three rolls to prepare a solution of the photosensitive resin composition.

Example 2 To 100 parts of the photosensitive resin obtained in Synthesis Example 1, 8.0 parts of benzyl diethyl ketal, 0.8 parts of diethylthioxanthone, 8.0 parts of trimethylolpropane triacrylate, 8.0 parts of biphenyl-4,4'-diglycidyl ether 8.0 Part, phthalocyanine green 0.5 part, and talc 8.0 part were mixed and dispersed with a three-roll mill to prepare a solution of the photosensitive resin composition.

Example 3 To 100 parts of the photosensitive resin obtained in Synthesis Example 1, 8.0 parts of benzyldiethyl ketal, 0.8 parts of diethylthioxanthone, 8.0 parts of dipentaerythritol hexaacrylate, 8.0 parts of biphenyl-4,4'-diglycidyl ether 8.0 Part, 2-methylimidazole 1.0 part, phthalocyanine green 0.5 part,
8.0 parts of talc were mixed and dispersed with a three-roll mill to prepare a solution of the photosensitive resin composition.

Comparative Example 1 To 100 parts of the photosensitive resin obtained in Synthesis Example 1, 8.0 parts of benzyl diethyl ketal, 8.0 parts of biphenyl-4,4'-diglycidyl ether, 0.5 part of phthalocyanine green, talc
8.0 parts were mixed and dispersed with a three-roll mill to prepare a solution of the photosensitive resin composition.

Comparative Example 2 To 100 parts of the photosensitive resin obtained in Synthesis Example 1, 8.0 parts of benzyldiethyl ketal, 0.8 parts of diethylthioxanthone, 8.0 parts of trimethylolpropane triacrylate, 0.5 parts of phthalocyanine green, and 3 parts of 8.0 parts of talc It was mixed and dispersed with a roll to prepare a solution of the photosensitive resin composition.

Comparative Example 3 To 100 parts of the photosensitive resin obtained in Synthesis Example 2, 8.0 parts of benzyl diethyl ketal, 0.8 parts of diethylthioxanthone, 8.0 parts of trimethylolpropane triacrylate, 8.0 parts of biphenyl-4,4'-diglycidyl ether 8.0 , 1.0 part of 2-methylimidazole, 0.5 part of phthalocyanine green, and 8.0 parts of talc were mixed and dispersed with a three-roll mill to prepare a solution of a photosensitive resin composition.

Test Examples Coating films were prepared from the ink compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 3 by the method described above. In other words, a screen-printed substrate (wet35μ
m) Coating, preliminary drying (80 ° C-20 minutes), exposure (600mj / cm
² ) A cured coating film is prepared by development (1% aqueous solution of sodium carbonate, 60 seconds) and post cure (150 ° C. for 30 minutes)
After that, each performance was evaluated by the following test methods and evaluation judgment. 1) Solder heat resistance According to the test method of JIS C 6481, the cured coating film prepared as described above was immersed in a solder bath at 260 ° C for 30 seconds, and a peeling test using cellophane tape was performed in one cycle.
The state of the coating film after performing ~ 3 cycles was evaluated. ◎: No change in the coating film after 3 cycles. も の: Only slight change after 3 cycles. Δ: Change after 2 cycles. ×: Detachment after 1 cycle. 2) Chemical resistance. The state of the coating film after immersing the coating film in 10% hydrochloric acid for 30 minutes was evaluated. ◎: No change observed ○: Slight change Δ: Notable change ×: Coating swelled and peeled 3) Solvent resistance Cured coating was changed to methylene chloride The state of the coating film after immersion for 30 minutes was evaluated. ◎: No change observed ○: Slight change △: Notable change ×: Coating swelled and peeled 4) Electrical properties (insulation resistance and discoloration) Coating Place the comb-shaped electrode of the IPC-SM-840B B-25 test coupon in the chamber and apply D.C100V in a thermo-hygrostat at 60 ° C and 90% RH.
The insulation resistance after 00 hrs and the discoloration of the copper foil were evaluated. ：: No discoloration at all ○: Thinly discolored △: Notable discoloration ×: Black and scorched 5) Thermal shock test -40 ℃ -30min / 120 ℃ -30min The coating film was placed on a cycle tester having one cycle, and the state of the coating film after 2000 cycles was evaluated. ◎: No abnormality in the coating film ○: Slight cracking in the coating film △: Significant cracking in the coating film ×: Peeling of the coating film The above results are shown in Table 1. .

[0026]

[Table 1] As is clear from the above test results, the photosensitive resin composition of the present invention is a composition excellent in solder heat resistance, chemical resistance, solvent resistance, electrical properties and thermal shock resistance.

[0027]

As described above, the photosensitive resin composition of the present invention is excellent in heat resistance, chemical resistance, solvent resistance, electric properties, etc., and can be used as a solder resist, Photosensitive adhesive, plastic relief material,
It is a very useful composition that can be used for a wide range of printing plate materials.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H05K 3/06 H05K 3/06 H 3/28 3/28 D (72) Inventor Yoshikazu Ogo 16 Sayamagahara, Iruma-shi, Saitama -2 Within Tamura Kaken Co., Ltd. (56) References JP-A-4-170547 (JP, A) JP-A-1-203424 (JP, A) JP-A-62-264045 (JP, A) JP-A-55 -29849 (JP, A) JP-A-1-296240 (JP, A) JP-A-57-205736 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F 7/038 G03F 7/004 G03F 7/028 G03F 7/032 G03F 7/075 H05K 3/06 H05K 3/28

Claims (4)

(57) [Claims] 1. An epoxy resin having an unsaturated bond in a molecule obtained by reacting a part of an epoxy group of a polyfunctional epoxy resin with (meth) acrylic acid, and a radical-reactive unsaturated bond in a molecule. (Meth) acrylic acid is used in an equivalent ratio of 1 / 0.8 to an unreacted epoxy group in a silicone-modified epoxy resin obtained by reacting an organic silicone compound having
1.2 Addition of polybasic anhydride to hydroxyl groups of the resulting silicone-modified epoxy acrylate in an equivalent ratio of 1 /
A photosensitive resin composition developable with a dilute aqueous alkali solution, comprising a substance obtained by addition reaction of 0.3 to 1.0, b) a photopolymerization initiator, c) a reactive diluent, and d) a thermosetting compound. . 2. The photosensitive resin composition according to claim 1, wherein the photopolymerization initiator is contained in an amount of 0.5 to 50 parts by weight based on 100 parts by weight of the substance (a). 3. The reactive diluent is a photopolymerizable vinyl monomer having two or more double bonds in a molecule, and the substance 1) as component a)
3. The composition of claim 1, wherein the content is 2.0 to 4.0 parts by weight based on 00 parts by weight.
The photosensitive resin composition of item. 4. The photosensitive resin composition according to claim 1, wherein the thermosetting agent is Chemical formula 1. Embedded image (Wherein, R _{1 to} R ₄ are the same or different and each represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms)