JPH02111950A - Photosensitive resin composition and photosensitive element - Google Patents

Abstract

PURPOSE:To obtain a solder mask which can be developed with a noncombustible developer and has high resolution, high heat resistance and high workability in blanking by using a photosensitive resin compsn. contg. a photopolymerizable unsatd. compd. obtd. by a reaction between an epoxy resin having polysulfide skeletons and an unsatd. carboxylic acid, then allowing a univalent isocyanate to react with said photopolymerizable unsatd. compd. CONSTITUTION:A photosensitive resin compsn. consisting of (a) a photopolymerizable unsatd. compd., (b) a sensitizing agent and/or a sensitizing system which generates free radicals by the effect of active rays, and (c) a heat-curing agent, is useable as a solder mask for the production of a print-circuit board or a resist for chemical plating. The photopolymerizable unsatd. compd. (a) is obtd. by producing an unsatd. compd. by an addition reaction of an epoxy resin having polysulfide skeletons and being expressed by the formula I with an unsatd. carboxylic acid in 0.1-0.98 ratio of acid equivalent/epoxy equivalent, then allowing a univalent isocyanate to react with secondary OH groups of the unsatd. compd. in 0.1-1.2 ratio of isocyanate equivalent/OH equivalent. Thus, a thick film solder mask which can be developed with a noncombustible developing soln, can be produced by a photographic process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photosensitive resin composition, and in particular, a photosensitive resin suitable for use in forming a protective film in the production of a 1-YA board, full-bending precision processing, etc. Compositions and photosensitive elements.

[Conventional technology]

Conventionally, photosensitive resin compositions have been used in solder masks, chemical plating resists, and the like in the printed wiring board industry. The main purpose of a solder mask is to limit the soldering area during soldering, to prevent solder bridging, etc., to prevent corrosion of bare conductors, and to maintain electrical insulation between conductors over a long period of time. That's true. Usually, as a solder mask, one (printed mask) whose main component is a thermosetting resin such as an epoxy resin or an aminoplast resin is used.

However, in recent years, the wiring density of printed wiring boards has increased, and the requirements for electrical insulation between conductors have also become stricter, and the solder masks used for this have also been required to be thick and have excellent dimensional accuracy. It is no longer possible to deal with this problem using conventional methods.

Therefore, by using a photographic method in which an image is formed by development after imagewise exposure, it is possible to form a solder mask with high reliability and excellent dimensional accuracy, which has a film thickness of approximately 25 μm on the conductor, and which cracks in the plate press machine. It is desired to develop a photosensitive resin composition that does not cause such problems.

Conventionally, as a photosensitive resin composition for forming a solder mask, for example, (1) JP-A-53-56018;
A photosensitive resin composition containing an acrylic polymer and a photopolymerizable monomer as main components disclosed in Publication No. 4-1018 and the like,
(2) JP-A-52-37996, JP-A-58-6
A photosensitive resin composition containing as main components an epoxy resin imparted with photoreactivity and an epoxy resin curing agent disclosed in JP-A No. 2636, JP-A No. 62-74920, etc., (3
) Isocyanatoethyl methacrylate modified illuminating resin compositions disclosed in JP-A-61-132947 and the like are known.

The photosensitive resin composition in ( ) above is a flame-retardant material used in ordinary photosensitive film materials for etching and plating (for example, DuPont's Riston product name, Hitachi Chemical's Photek product name, etc.). It can be developed with 1.1, I-trichloroethane, and a high-resolution solder mask can be formed, but since a large amount of acrylic polymer is used to provide film properties, the heat resistance of the cured film is There is a drawback that it is not sufficient.

Furthermore, the photosensitive resin composition (2) is based on an epoxy resin and has excellent heat resistance of the cured film, but is insoluble in flame-retardant N-containing solvents such as 1,1.1-)lichloroethane. In this case, it is necessary to use a flammable organic solvent such as cyclohexanone as a developer, which poses a safety problem. Furthermore, even when a flame retardant developer such as 1,1.1-) dichlorethane can be used, there is a drawback that cranks tend to occur during punching.

Furthermore, the photosensitive resin composition of (3) has excellent heat resistance of the cured film, and 1. A flame retardant developer such as 1,1-1-lichloroethane can be used, but there is a problem in that it tends to cause cracks during punching.

[Problem to be solved by the invention]

The purpose of the present invention is to solve the problems of the prior art, and 1.
1.1-) A photosensitive resin composition that can be developed with a flame-retardant developer such as lychloroethane and that can yield a highly reliable solder mask with excellent resolution, heat resistance, and punching workability, and its use The object of the present invention is to provide a photosensitive element with a high temperature.

[Means to solve the problem]

The present invention provides: (a) CHz-CI-C11z-3-(CzH4-0
-CIIzO-CzH4-5-5)ll\1 υ (where n is a positive integer), an epoxy resin (hereinafter referred to as an epoxy resin having a polysulfide skeleton) and an unsaturated carboxylic acid are mixed in an amount of acid equivalent/ A monovalent isocyanate is added to the secondary hydroxyl group of an unsaturated compound obtained by addition reaction at an epoxy equivalent ratio of 0.1 to 0.98, and an isocyanate equivalent/hydroxyl group equivalent ratio of 0.1 to 0.98. 1.
A photopolymerizable unsaturated compound obtained by reacting in the range of 2,
The present invention relates to a photosensitive resin composition containing (F) an exacerbating agent and/or a sensitizing system that generates free radicals by actinic light, and (C) a heat curing agent.

The photopolymerizable unsaturated compound (a) used in the present invention comprises an epoxy resin having a polysulfide skeleton and an unsaturated carboxylic acid, and the ratio of acid equivalent/epoxy equivalent is 0.1 to 0.
A monovalent isocyanate is reacted with a secondary hydroxyl group of an unsaturated compound obtained by an addition reaction in a range of 98 to 72 in a ratio of isocyanate equivalent/water fft72 equivalent in a range of 0.1 to 1.2. can get.

As the epoxy resin having a polysulfide skeleton, for example, FLEP-10 (trade name, manufactured by Toshi Thiokol Co., Ltd.) is used.
Viscosity (25°C) 680 poise, epoxy equivalent 360,
Specific gravity (20°C) 1.2), FLEP-50 (viscosity (2
5°C) 270 poise, epoxy equivalent 310, specific gravity (2
0°C) 1.2) etc. are used.

As the unsaturated carboxylic acid, acrylic acid, methacrylic acid, β-furylacrylic acid, β-styrylacrylic acid, α-cyanocinnamic acid, cinnamic acid, etc. are used.

The unsaturated compound is obtained by an addition reaction between an epoxy resin having a polysulfide skeleton and an unsaturated carboxylic acid. The ratio of acid equivalent/epoxy equivalent at this time is 0.1 to 0.9
The range is 8. If the corresponding amount ratio is less than 0.1, the photocured film will easily swell during the development process after image exposure.
When it exceeds 98, adhesion and heat resistance decrease. The above addition reaction is a reaction shown in the following formula, and is carried out by a conventional method.

For example, the epoxy resin having a polysulfide skeleton is dissolved in an inert organic solvent such as methyl ethyl ketone, methyl cellosolve acetate, ethyl cellosolve acetate, cyclohexanone, etc. as necessary, and a catalyst such as triethylamine, tri-n-butylamine, diethylcyclohexylamine, etc. Tertiary amines, quaternary ammonium salts such as benzyltriethylammonium chloride, etc. are used, and hydroquinone, p-methoxyphenol, etc. are used as polymerization inhibitors, and 70%
It is obtained by stirring the reaction at ~110°C within the range of the above equivalent ratio.

As the monovalent isocyanate, aliphatic isocyanates such as ethyl isocyanate, n-butyl isocyanate, and octadecyl isocyanate, aromatic isocyanates such as phenyl isocyanate, and ethyl isocyanate methacrylate are used.

In the photopolymerizable unsaturated compound (a) in the present invention, the secondary hydroxyl group of the unsaturated compound and the monovalent isocyanate have a ratio of isocyanate equivalent/hydroxyl group equivalent of 0.1 to 1.
．． 2 by a conventional method. When the ratio of isocyanate equivalent/hydroxyl group equivalent is less than O.1, it is 1
．． 1.1-) Development with a flame-retardant organic solvent such as lychloroethane becomes difficult and photocurability decreases, and if it exceeds 1 or 2, gelation tends to occur during reaction and properties such as heat resistance deteriorate.

This reaction is carried out according to the following formula. Isocyanate 50-1
Stir and react at 10'C.

Under such reaction conditions, side reactions such as the reaction between urethane bonds and epoxy groups and thermal polymerization of unsaturated bonds can be prevented, and as a result, photopolymerizable unsaturated compounds can be formed without forming gel-like substances. (a) can be obtained. After the reaction,
From the viewpoint of safety and improving storage stability, it is preferable to urethanize and deactivate the remaining monovalent isocyanate using an alcohol such as methanol, ethanol, or 2-hydroxyethyl methacrylate.

The photosensitive resin composition of the present invention contains as an essential component 0)) an exacerbating agent and/or a sensitizing system that generates free radicals by actinic light.

Examples of aggravating agents include substituted or unsubstituted polynuclear quinones, such as 2-ethylanthraquinone, 2t-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2゜3-diphenylanthraquinone, and ketoaldonyls such as diacetylbenzyl. compounds, α-ketaldonyl alcohols and ethers such as benzoin and pivalone, α-hydrocarbon-substituted aromatic acyloins such as α-phenyl-benzoin, α, α-diethoxyacetophenone, etc., benzophenone, 4.49- Aromatic ketones such as bisdialkylaminobenzophenone, thioxanthone such as 2-methylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, and 2-ethylthioxanthone are used, and these may be used alone or in combination. Two or more types may be used in combination.

As a sensitizing system, for example, a combination of 2,4.5-) realyl imidazole dimer and 2-mercaptobenzoquinazole, leuco crystal violet, tris(4-diethylamino-2-methylphenyl)methane, etc. used. Also, additives which do not have photoinitiating properties by themselves, but which, when used in combination with the above-mentioned substances, result in a sensitizer system with better overall photoinitiating performance, for example, tertiary amines such as triethanolamine for benzophenone; For thioxanthone, isoamyl dimethylaminobenzoate, N-methyldietalamine, bisethylaminobenzophenone, etc. can also be used.

From the viewpoint of resolution and soldering heat resistance, the sensitizer and/or sensitizing system (b) is a photopolymerizable unsaturated compound (a) 100%
It is preferable to use it in a range of 0.1 to 30 parts by weight.

Moreover, the photosensitive resin composition of the present invention contains a heat curing agent as an essential component (C).

Examples of the heat curing agent (C) include 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 2,4-diamino-6-[2-undecyl-imidazole-(1))-ethyl- Imidazole curing agents such as 5-t-lyazine, biguanide curing agents such as 1-(0-tolyl) biguanide and 2,6-xylyl biguanide, FB, -monoethylamine complex, BF3) reethanolamine complex, etc. A boron trifluoride amino complex, a fluoroboric acid amine salt, an amine imide type curing agent (Epicure YPH-201 manufactured by Yuka Silk Epoxy Co., Ltd.), dicyandiamide, and the like are used. These heat curing agents (C) are
Preferably, latent curing agents are used, alone or in combination
Used in combination of more than one species.

The amount of heat curing agent (C) used is not particularly limited, but from the viewpoint of solvent resistance of the solder mask, photopolymerizable unsaturated compound (a
) It is preferable to use it in a range of 0.5 to 10 parts by weight per 100 parts by weight.

The photosensitive resin composition of the present invention may contain other photopolymerizable compounds. Other photopolymerizable compounds include, for example, trimethylolpropane triacrylate, pentaerythritol triacrylate-1, trimethylhexamethylene diisocyanate/2-hydroxyethyl acrylate (1/2 molar ratio) reaction product, isocyanate ethyl Examples include methacrylate/water (2/1 molar ratio) reactants.

Furthermore, photopolymerizable compounds disclosed in JP-A-53-56018 can also be used. The content of these other photopolymerizable compounds is preferably 10% by weight or less based on the photopolymerizable unsaturated compound (a) from the viewpoint of heat resistance.

Moreover, the photosensitive resin composition of the present invention may contain a particulate filler. Examples of the fine particulate filler include talc,
Silica, titanium oxide, clay, calcium carbonate, hydrated silicic acid, aluminum hydroxide, alumina, barium sulfate, antimony dioxide, magnesium carbonate, mica powder, aluminum silicate, magnesium silicate, etc. are used.

The particle size of the particulate filler is preferably 0.01 to 10 μm, more preferably 0.01 to 1.5 μm, from the viewpoint of preventing deterioration of resolution, adhesion of the cured film, and the like. It is preferable that the fine particulate filler is uniformly dispersed in the photosensitive resin composition.

In addition, the surface of the fine particulate filler is treated with a silane coupling agent having a functional group such as a hydroxyl group, an amino group, an epoxy group, or a vinyl group in order to increase the adhesive strength with the photopolymerizable unsaturated compound. You can also. Examples of the silane coupling agent include T-aminopropyltriethoxysilane, β-aminoethyl-γ-aminopropyltrimethoxysilane, T-glycidoxypropyltrimethoxysilane, and T-methacryloxypropyltrimethoxysilane. used.

The content of these particulate fillers is preferably 40% by weight or less based on the photopolymerizable unsaturated compound (a) from the viewpoint of surface gloss and punching processability.

Furthermore, the photosensitive resin composition of the present invention includes other secondary components,
For example, it may contain a polymeric binder, a thermal polymerization inhibitor, a dye, a pigment, a coatability improver, an antifoaming agent, a flame retardant, a reversibility improver, and the like.

The photosensitive resin composition of the present invention contains a photopolymerizable unsaturated compound (
a), a sensitizer and/or a sensitizing system that generates free radicals by actinic light), a heat curing agent (C), and other components are stirred and mixed using a stirrer such as a kneader or Daysilver. Obtainable.

When a particulate filler is mixed, it is preferable to disperse and mix it using a dispersing machine that uses crushing force due to high shear force, such as a three-roll mill, a ball mill, or a colloid mill.

The photosensitive resin composition of the present invention can be applied directly onto a substrate to be processed and protected by conventional methods such as dip coating, flow coating, and screen printing to easily form a photosensitive layer with a thickness of 10 to 150 μm. be able to. When coating, if necessary, the composition can be dissolved in a solvent. As the solvent, for example, acetone, methyl ethyl ketone, methyl cellosolve acetate, ethyl cellosolve acetate, cyclohexanone, methyl cellosolve, methylene chloride, 1,1.1-)cycloethane, etc. can be used.

Further, the above solution is applied onto a film such as a polyethylene terephthalate film or a polyimide film by a knife coating method or a roll coating method, and the photosensitive element obtained by drying is heated and pressed onto a substrate using a hot roll. A photosensitive layer can also be formed by laminating them. At this time, if the substrate has irregularities of 10 μm or more, such as a printed wiring board on which conductor wiring lines are formed, it is preferable to laminate under a vacuum of 200 m+++Hg or less to prevent air from being entrained. As this device, for example,
A laminating apparatus described in Japanese Patent No. 5-13341 is used. In addition, when using a support film that is opaque to actinic light, it is necessary to peel off the support film at the time of exposure.

Exposure and development of the obtained photosensitive layer are carried out by conventional methods. That is, using an ultra-high-pressure mercury lamp, high-pressure mercury lamp, or the like as a light source, the layer of the photosensitive resin composition is imagewise exposed directly or through a negative mask through a transparent film such as a polyethylene terephthalate film. If a transparent film remains after exposure, it is peeled off and developed.

As a developer, a developer containing flame-retardant 1.1.1-)lichloroethane as a main component, such as Three-One EX-R (trade name, manufactured by Toagosei Kagaku Co., Ltd.), Eterna IRC (trade name, manufactured by Asahi Kasei Industries, Ltd.), etc. used. For example, 1,1.1-
Halogenated hydrocarbons such as 1-lychloroethane can also be used.

The image-like protective film obtained by the above method has properties as a corrosion-resistant film for ordinary etching, plating, etc., but after development, exposure to active light and heat treatment at 80 to 200°C are necessary. By carrying out this process, properties such as adhesion, heat resistance, solvent resistance, and punching workability can be improved, and a permanent protective film that satisfies the properties of an 8-photoresin composition such as a solder mask can be obtained.

〔Example〕

The present invention will be explained below using examples. In addition, in the examples, parts mean parts by weight.

Example 1 (a) Synthesis of photopolymerizable unsaturated compounds Ethyl cellosolve acetate 450 parts B, acrylic acid 75 parts p-methoxyphenol 3 parts dibutyltin dilaurate
0.2 parts, methanol
Add the above A to a 2N reactor that can be heated and cooled and equipped with a 9-part thermometer, stirrer, cooling tube, and dropper, raise the temperature to 60 ° C while stirring, and add to this while keeping warm. B was added dropwise over about 1 hour. After that, 2
The temperature was brought to 80°C over a period of time, and stirring was continued at 80°C for about 15 hours to bring the acid value of the reaction system to 2.1.

Next, lower the temperature to 60°C and keep it warm.
C was uniformly added dropwise to this over a period of about 3 hours.

After dropping C, the reaction temperature was gradually increased to 80°C over about 1 hour.
After raising the temperature to 60°C, add D to approx.
Stirring was continued for an hour. In this way, a solution (i) of a photopolymerizable unsaturated compound having a nonvolatile content of 69% by weight was obtained.

(b) Preparation of photosensitive resin composition Solution (i) 1 of photopolymerizable unsaturated compound obtained in (a)
To 45 parts (solid content 100 parts), 5 parts of benzophenone and 2 parts of 2-methylimidazole (manufactured by Shikoku Kasei Co., Ltd., trade name: CUREZOL 2MZ) were added and stirred to form a homogeneous solution (
1-1) was adjusted.

(C) Formation of a cured film The solution (I-1) of the photosensitive resin composition obtained in (b) was applied to a copper-clad laminate (manufactured by Hitachi Chemical Co., Ltd., M CL-E-6).
1. Apply on a plate with a thickness of 1.6 mm and leave it for 20 minutes at room temperature.
It was dried at 80°C for 20 minutes to form a photosensitive layer with a thickness of 40 μm.

Next, the exposure stage (Oak Manufacturing Co., Ltd., H
MW-590 model) and was exposed at 500 mJ/afl. After exposure, the film was heated at 80°C for 5 minutes, cooled to room temperature, and then developed by spraying with 1,1.1-)lichloroethane at 18°C for 60 seconds.

Next, heat treatment was performed at 150° C. for 90 minutes to obtain a solder mask with excellent dimensional accuracy suitable for a photographic plate.

This solder mask has a glossy surface, and was cut at room temperature using a shear (IMS-200 model manufactured by Hobenjo Co., Ltd.) and visually observed for cracks and peeling on the cut surface. I couldn't see it. Also, a press punching machine (manufactured by Yamada Dobby Co., Ltd., C-shaped frame, load 20 tons)
Using a mold shown in US ASTM D61744,
Punching, crank,
When the peeling was visually observed, no crank or peeling was observed on the cut surface.

In addition, as a heat resistance test, rosin-based flux A-226
(manufactured by Tamura Kaken Co., Ltd.) at 260°C for 10 seconds, and after cleaning with Triclean for 10 minutes at 25°C, M I L-3TD-202E107
D Condition B (-65°C/30 minutes, room temperature within 5 minutes, 12
When a thermal shock test was conducted for 50 cycles (5°C/30 minutes), no cracks were observed and no peeling of the coating was observed, indicating excellent long-term reliability.゛Example 2 Solution (i) of the photopolymerizable unsaturated compound obtained in Example 1
114 parts (solid content 80 parts), 2-methyl-(4-(methylthio)phenyl]-2-morpholino-1-propane (manufactured by Ciba Geigy, trade name IRGACURE 907)
) 6 parts, talc (manufactured by Nippon Talc Co., Ltd., average particle size 1.5 μm
, trade name Micro Ace P-4) 7 parts, silica (manufactured by Ryumori Co., Ltd., average particle size 5 μm, trade name Crystallite 5V) 13 parts, Phthalocyanine Green 0.2 part, Curesol 2M
2 2 parts and 0 or 1 part of a polymethacrylate leveling agent (manufactured by Mitsubishi Monsanto, trade name Modaflow) were blended and separated using three rolls to form a photosensitive resin composition (1-
2) was adjusted.

Using the obtained photosensitive resin composition (1-2), a cured film was formed in the same manner as in Example 1 (C), and a test was conducted. The obtained solder mask had surface gloss. No cracks or peeling were observed on the cut surfaces during cutting with a shear and punching with a press, and the material was heat resistant.

Example 3 Angry photogenic jinii pilgrimage product obtained in Example 2 (1-2), 200
7 parts of trimethylolpropane triacrylate was added to adjust the photosensitivity (I fat composition (1-3)). Using the photosensitivity (M fat composition (1-3)), Example 1 (C
), a cured film was formed at 1M, and a test was conducted. The obtained solder mask had a glossy surface, and no cracks or peeling were observed on the cut surface after cutting with a shear and handling with a press. It also had excellent heat resistance.

Comparative Example 1 (a) Synthesis of photopolymerizable unsaturated compound Methyl ethyl ketone 400 parts Part B. Lilic acid 35 parts Benzyltrimethylammonium chloride 3.5 parts p-methoxyphenol 3 parts Methyl ethyl ketone 50 parts C, isocyanate Ethyl methacrylate 81 parts Dibutyltin dilaurate
0.3 parts methyl ethyl ketone
50 parts methanol 5 parts Example 1 (a) A photopolymerizable unsaturated compound was synthesized in the same manner as in Example 1 (a) except that the above A, B, C, and D were used. A solution (II) of a photopolymerizable unsaturated compound with a concentration of 57% was obtained.

(g)) Preparation of photosensitive resin composition To 175 parts of photopolymerizable unsaturated compound solution (II) (solid content: 100 parts), 5 parts of pentuphenone and 22 parts of Curesol 2M were added and stirred to form a homogeneous furuzuke (II). -1
) was adjusted.

(C) Formation of a cured film Example 1 In (C), a cured film was formed in the same manner as in Example 1(C) except that the solution ([[-1) was used. The obtained solder mask had a glossy surface and excellent heat resistance, but peeling and cracking occurred on the cut surfaces in cutting tests using a jar and punching tests using a press machine.

Comparative Example 2 140 parts of photopolymerizable unsaturated compound solution (■) (solid content 8
0 parts), 907.6 parts of IGRACURE, 7 parts of Micro Ace P-4, 13 parts of Crystallite 5, 0.2 parts of Phthalocyanine Green, 22 parts of Curesol 2M, and 0.1 part of Modaflow, and mixed in three rolls. A photosensitive resin composition (n-2) was prepared by dispersing it.

Furthermore, a cured film was formed using the photosensitive resin composition (II-2) in the same manner as in Example 1(C). The obtained solder mask had a glossy surface and was excellent in heat resistance, but peeling and cracking occurred on the cut surface in cutting tests using a shear and punching tests using a press machine.

[Effect of the invention] According to the photosensitive resin composition of the present invention, it has surface gloss,
A cured film with excellent cuttability with a shear and punching with a press can be obtained. In addition, it can be developed with an xqt t2B developer containing 11.1-trichloroethane as the main component,
Furthermore, it is also possible to form a single film solder mask using a photographic method.

Therefore, the cured film obtained using the photosensitive resin composition of the present invention can be used as a permanent protective film for coating, coating, plating, etc., and for solder masks and the like. Furthermore, since it has excellent chemical and physical properties, it can be used for interlayer insulation layers of multilayer printed wiring boards, luminous adhesives, paints, plastic reliefs, printing plate materials, metal-rich processing materials, etc.

Claims (1)

[Scope of Claims] 1. (a) ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (where n is a positive integer) The epoxy resin and unsaturated carboxylic acid are combined in an acid equivalent/epoxy equivalent ratio. is 0.
A monovalent isocyanate is reacted with a secondary hydroxyl group of an unsaturated compound obtained by addition reaction in a range of 1 to 0.98, with a ratio of isocyanate equivalent/hydroxyl group equivalent in a range of 0.1 to 1.2. A photosensitive resin composition comprising: (b) a sensitizer and/or a sensitizing system that generates free radicals by actinic light; and (c) a heat curing agent. 2. A photosensitive element obtained by applying a solution of the photosensitive resin composition according to claim 1 onto a film and drying it.