JPH02173750A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE:To obtain the compsn. which is excellent in a photosetting property, heat resistance, chemical resistance, flexibility, and electrical characteristics, and is useful as a liquid photoresist which can be developed with a dilute aq. alkaline soln. by using a specific multifunctional epoxy resin. CONSTITUTION:This compsn. contains the reaction product obtd. by bringing polymerizable unsatd. carboxylic acid at 0.8 to 1.2mol% per 1 epoxy equiv. of a mixture composed of the epoxy resin expressed by formula I and the epoxy resin expressed by formula II into reaction with the above-mentioned mixture and further bringing the reaction product thereof and 0.2 to 1.0mol polybasic acid anhydride into reaction, a diluent, a sensitizer, the epoxy resin, and an epoxy resin hardener. This compsn. can be developed by the dilute aq. alkaline soln. and the mixing ratio of the epoxy resins expressed by formula I and formula II is so determined as to attain 80:20 to 60:40 by weight. The resin compsn. which has the excellent heat resistance, chemical resistance and adhesive property and is usable not only as a solder resist but also in broad applications, such as paints, photosensitive adhesive agents, plastic relief materials, and materials for printing plates, is obtd. in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a photosensitive resin composition, and more particularly to an ultraviolet curable resin composition that can form an image by exposure to ultraviolet light and development with a dilute aqueous alkaline solution after forming a resin film. The present invention relates to a photosensitive resin composition useful as a liquid photosolder resist with excellent heat resistance.

[Conventional technology]

It is common practice to use printed wiring boards to compactly incorporate electronic components. This printed wiring board is made by laminating copper foil on a laminated board and etching it according to the circuit wiring, and then electronic components are placed in predetermined locations and soldered.

Solder resist is used in the pre-process of soldering electronic components to such printed wiring boards, and is a film formed on the entire surface of the circuit conductor except for the parts to be soldered. Such a film functions as an insulating film that prevents solder from adhering to unnecessary parts during soldering, and also protects circuit conductors from being corroded by oxidation and moisture when exposed directly to the air. It also functions as a protective film to prevent damage, and is indispensable.

Conventionally, such solder resists have been formed by screen printing on a substrate and curing with ultraviolet rays or heat. However, printed circuit boards are becoming increasingly finer, more numerous, and more integrated into one board in order to achieve higher density, and as they become more sophisticated at a remarkable pace, mounting methods are becoming increasingly popular with surface mount technology (SMT). It has progressed step by step. Demand for high resolution, high precision, and high reliability for solder resists has increased as SMT becomes finer. Regardless of whether it is a consumer-use board or an industrial board, the screen printing method has changed to a liquid type that has excellent positional accuracy and coverage of conductor edges. A photoresist method has been proposed. For example, JP-A-50-144431 and JP-B-Sho 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. However, the unexposed portions of these solder resists were removed using an organic solvent and developed. However, this removal (development) of unexposed areas using an organic solvent is problematic because it involves the use of a large amount of organic solvent, which poses risks such as environmental pollution and fire. In particular, the problem of environmental pollution has recently come under the spotlight for its effects on the human body, and the reality is that we are struggling to find countermeasures.

To solve this problem, an alkali-developable photo solder resist that can be developed with a dilute alkaline aqueous solution has been proposed.

1984 Special Publication as an ultraviolet curable material that can be developed with alkali
No. 40329 and Japanese Patent Publication No. 57-45785 disclose materials in which a base polymer is a reaction product obtained by reacting an epoxy resin with an unsaturated monocarboxylic acid and further adding a polybasic acid anhydride. Further, JP-A-61-243869 discloses a liquid solder resist composition using a novolac type epoxy resin, which has good heat resistance and chemical resistance, and can be developed with a dilute aqueous alkaline solution.

[Problem to be solved by the invention]

The purpose of the present invention is to use a new multifunctional epoxy resin other than the above-mentioned bisphenol type or novolac type epoxy resin to create a material with excellent photocurability, heat resistance, chemical resistance, flexibility, and electrical properties. An object of the present invention is to provide a photosensitive resin composition useful as a liquid photoresist that can be developed with a dilute aqueous alkaline solution.

[Means to solve the problem]

In the present invention, a mixture of an epoxy resin represented by the following formula (1) and an epoxy resin represented by the following formula (II) is added in an amount of 0.8 to 1.2 moles per 1 epoxy equivalent of the mixture. After reacting a saturated carboxylic acid, a reaction product obtained by further reacting with 0.2 to 1.0 mol of polybasic acid anhydride per 1 epoxy equivalent, (b) diluent, (c) sensitization (d) an epoxy resin; and (e) an epoxy resin curing agent. ] The mixing ratio of the epoxy resin is 80:20 to 60: by weight.
40 and the blending ratio of the composition is (a) 4 (1-60 parts by weight), (b) 5-50 parts by weight, (c) 3-10 parts by weight, (d) 10-20 parts by weight. parts by weight, (e) preferably 0.5 to 3 parts by weight.

Next, the present invention will be explained in detail.

The epoxy resin to be reacted with the polymerizable unsaturated carboxylic acid used in the present invention has formulas (1) and (II). Things may stick to the composition, uneven gloss may occur on the surface of the cured composition, and the heat resistance may also be slightly inferior.

Examples of the polymerizable unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, and cinnamic acid, with acrylic acid being particularly preferred.

In the reaction between the epoxy group and the polymerizable unsaturated carboxylic acid, it is presumed that esterification occurs through the reaction described below. Therefore, the number of epoxy groups and the number of polymerizable unsaturated groups should approximately correspond.

A mixture of epoxy resins represented by (13 epoxy resin and (II) epoxy resin in a weight ratio of 80
:20-60 :40 is preferable.

If the amount of the epoxy resin (1) is too large, the removability with a dilute alkaline aqueous solution may be slightly poor and development defects may occur easily, and if the amount of the epoxy resin (II) is too large (epoxy compound)
(Polymerizable unsaturated basic acid) (esterified product) The polybasic acid anhydride used in the present invention has developability.

Hexahydrophthalic anhydride, 3-methylhexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, 3-methylhexahydrophthalic anhydride due to its reactivity with the epoxy resin, which is a thermosetting component.
Ethyltetrahydrophthalic anhydride, 4-ethylhexahydrophthalic anhydride, tetrahydrophthalic anhydride,
Preferred are 3-methyltetrahydrophthalic anhydride, 4-methyltetrahydrophthalic anhydride, 3-ethyltetrahydrophthalic anhydride, 4-ethyltetrahydrophthalic anhydride, and the like.

Examples of the diluent (b) include an unsaturated compound having at least two ethylene bonds and an organic solvent, but it is particularly preferable to use a combination of the two. Examples of the unsaturated compounds include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, glycerin tri(meth)acrylate, 1.3-propylene di(meth)acrylate, 1°2
．． 4-butanetrioltri(meth)acrylate, 1
, 4-benzenediol di(meth)acrylate, bis(meth)acrylate of polyethylene glycol having a molecular weight of 200-500, trimethylolpropane tri(meth)acrylate, pentaerythritol 1-rutetra(meth)acrylate, dipentaerythritol hexa( meth)acrylate, methylenebis(meth)acrylamide, diethylenetriaminetri(meth)acrylamidobis(methacrylamidopropoxy)ethane, bismethacrylamidoethyl methacrylate N-[(
β-hydroxyethyloxy)ethylcoacrylamide, divinyl phthalate, divinyl terephthalate, divinylbenzene-1,3-disulfonate, divinylbutane-1°4-disulfonate, triallyl isocyanurate, tri(meth)acrylic isocyanurate, xylylene bis(diallyl) isocyanurate), Tris(2,
3-dibromopropyl) isocyanurate, tris(3
-Mercaptopropyl) incyanurate, etc.
Examples of organic solvents include ethylene glycol monoalkyl ethers, diethylene glycol monoalkyl ethers, ethylene glycol dialkyl ethers, diethylene glycol dialkyl ethers, ethylene glycol monoalkyl ether acetates, diethylene glycol monoalkyl ether acetates, and other cyclohexanone.

Tetrahydronaphthalene, petroleum naphtha, etc. are used.
It is used to dilute it to make it easier to apply.

The sensitizer used in the present invention is not particularly limited, but especially 2-methyl-[4-(methylthio)phenyl]-2-
Particularly excellent ultraviolet curability can be obtained by using morpholino-1-propanone as the main component and one or two other sensitizers in combination. The sensitizers used in the above combination include p-phenylbenzophenone S benzyl dimethyl ketal, 2゜4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2
Examples include -isopropylthioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 4,4'-diethylaminobenzophenone, and p-dimethylaminobenzoic acid ethyl ester.

The epoxy resin (d) used in the present invention is not particularly limited, but compounds having at least two epoxy groups, such as bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, novolak type epoxy resin, etc. Epoxy resins, trisglycidyl isocyanuric acid, etc. are preferred, and trisglycidyl isocyanuric acid is particularly preferred. Compared to other epoxy resins, this trisglycidyl isocyanuric acid hardly dissolves in organic solvents, so it has good stability at low temperatures and high reactivity at high temperatures.

Furthermore, since it has a triazine skeleton, it has excellent heat resistance and electrical properties.

The epoxy resin curing agent (e) used in the present invention is not particularly limited, but S-triazine compounds are particularly preferred. For example, melamine, guanamine, acetoguanamine, benzoguanamine, ethyldiamino-s-triazine, 2,4- Preference is given to diamino-8-triazine, 2,4-diamino-6-tolyl-s-triazine, 2,4-diamino-6-xylyl-8-triazine and the like. This s-triazine compound not only serves as a latent curing agent for the epoxy resin, but also has the effect of improving the adhesive strength between the resist and the substrate and preventing electrolytic corrosion and discoloration of copper.

The photosensitive resin composition of the present invention includes (a) (b) (c)
(d) Consists of component (e), with a blending ratio of 40 to 60 parts by weight of the reaction product of (a) and 5 to 50 parts of the diluent of (b).
Parts by weight, 3 to 10 parts by weight of the sensitizer (c), 10 to 20 parts by weight of the epoxy resin (d), and 0.5 to 3 parts by weight of the epoxy resin curing agent (e) are preferred. , and various additives as necessary, such as silica, talc,
Extender pigments such as alumina, calcium carbonate, clay, and Aerosil, coloring pigments such as chrome phthalo yellow and cyanine green, silicone and fluorine-based antifoaming agents, leveling agents, antioxidants, and the like can be added.

The above-described photosensitive resin composition of the present invention is applied to a substrate to a desired thickness, and then heated at 60 to 80°C for 15 to 60 minutes to volatilize the organic solvent. The pattern is placed in contact with the coating on the substrate, and the pattern is selectively exposed to ultraviolet light. This causes the composition in the exposed areas of the coating to cross-link and become insoluble. The coating is then developed by removing the unexposed areas with a dilute aqueous alkaline solution. The dilute alkali aqueous solution used here is generally a 0.5 to 5% by weight aqueous sodium carbonate solution, but of course other alkalis can also be used. The pattern thus obtained was later exposed to ultraviolet light or 100-200 nm to improve heat resistance.
It is desirable to react (secondary curing) by applying heat at 00°C or far infrared rays.

Examples of the present invention are shown below, but the present invention is not limited thereto.

Synthesis Example 1> Epoxy acrylate was obtained by reacting 1 mole of acrylic acid with 1 epoxy equivalent of the epoxy resin of (1) using 30% by weight of butyl cellosolve acetate as a solvent. One hydroxyl equivalent of this epoxy acrylate was reacted with 0.5 mol of tetrahydrophthalic anhydride until the acid value reached the theoretical value.

This reaction product is designated as (a-1).

Synthesis Example 2> A reaction product [a-2] was obtained in the same manner as in Synthesis Example 1 except that an epoxy resin of structural formula (113) was used instead of the epoxy resin of formula CI) in Synthesis Example 1.

Examples 1 to 2, Comparative Examples 1 to 4 The components shown in Table 1 below were blended and kneaded in a roll mill to obtain photosensitive compositions.

(Margins below) Table 1 Screen printing of photosensitive compositions of silicone defoamer Examples 1 to 2 and Comparative Examples 1 to 4 manufactured by Shin-Etsu Chemical Co., Ltd. on the entire surface of a patterned copper-clad laminate that has been surface-treated. The coating was applied to a thickness of 20 to 30 μm. After that, 8
Dry in a hot air circulation dryer at 0°C for 30 minutes, attach a negative film of the desired pattern, and expose to ultraviolet rays with a wavelength of 365 nm and an intensity of 25++ W/al for 20 seconds.
Developed with aqueous sodium carbonate solution for 60 seconds, then developed with 15
It was heated and cured for 30 minutes in a hot air circulation dryer at 0°C. The obtained sample was evaluated for tack, developability, adhesion, coating film hardness, solvent resistance, acid resistance, and heat resistance after drying. The results are shown in Table-2.

(Margin below) Table-2 The above characteristic evaluation was conducted under the following conditions.

After completion of drying, the tackiness of the coating film was examined to the touch and evaluated according to the following criteria.

O: No tack at allΔ: Slight tack
．． Development was performed at a spray pressure of 7 kg/aJ and evaluation was made based on the following criteria.

0: Completely developed Δ: Slight residue X: Hardly developed 11 works
10×10) was prepared, a peeling test was conducted using cellophane tape, and the peeling condition of the stitches was evaluated based on the following criteria.

0: 100/100 Δ: 50/100~90/100 x: o/100~50/100 11 anti-peel Evaluation was performed according to JIS D 0202.

Salmon dishes were immersed in methylene chloride for 60 minutes at room temperature, and then subjected to a peeling test using Sellotape and evaluated using the following criteria.

0: No abnormality in the coating film ×: Blistering and peeling of the coating film After immersing the salmon disk in 10% hydrochloric acid at room temperature for 30 minutes, a peeling test with cellophane tape was conducted and evaluation was made according to the following criteria.

Q: There is no abnormality in the coating film. This was regarded as one cycle, and the evaluations for the first cycle and the third cycle were performed based on the following criteria.

0: No abnormality in the paint film Δ: Slight peeling of the paint film It was found that the characteristics were fully satisfied. Furthermore, the photosensitive resin composition of the present invention has excellent heat resistance, chemical resistance, and adhesion, and can be used not only as a solder resist, but also as a paint, a photosensitive adhesive, and a plastic relief material.

It can be used for a wide range of purposes such as printing material.

Claims (3)

[Claims] 1. A mixture of an epoxy resin represented by the following formula [I] and an epoxy resin represented by the following formula [II] is added with 0.8 to 1.2 moles of polymerizable unsaturated carboxylic acid per 1 epoxy equivalent of the mixture. After reacting, the reaction product obtained by further reacting with 0.2 to 1.0 mol of polybasic acid anhydride per 1 epoxy equivalent, (b) diluent, (c) sensitizer, (
A photosensitive resin composition developable with a dilute alkaline aqueous solution, characterized by containing (d) an epoxy resin and (e) an epoxy resin curing agent. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [II] 2. The mixing ratio of the epoxy resin of the above formula [I] and the epoxy resin of the above formula [II] is 80:20 to 60:
40. The photosensitive resin composition according to claim 1, wherein the photosensitive resin composition has a molecular weight of 40. 3. (a) 40 to 60 parts by weight, (b) 5 to 50 parts by weight, (c) 3 to 10 parts by weight, (d) 10 to 20 parts by weight, and (e) 0.5 to 3 parts by weight. The photosensitive resin composition according to claim 1 or 2, characterized in that: