JPH0524927B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ultraviolet curable resin composition, in particular, which is cured by ultraviolet rays and used as a permanent protective film for printed wiring boards, and has heat resistance, plating resistance,
The present invention relates to an ultraviolet curable resin composition suitable for solder resist ink having excellent moisture resistance, solvent resistance, chemical resistance, and electrical insulation properties.

(Problems to be Solved by the Invention) In recent years, ultraviolet curable resin compositions have been widely used for reasons such as resource saving, energy saving, improved workability, and improved productivity. In the field of printed wiring board processing, various inks such as solder resist inks and marking inks have been shifting from conventional thermosetting compositions to ultraviolet curable compositions for the same reason. Solder resist ink is
The company quickly transitioned to UV-curable compositions. However, the current applications of this ultraviolet curable resin composition are limited to so-called consumer substrates used in radios, videos, televisions, etc., and industrial substrates such as computers and control equipment. The reality is that it has not yet been applied to the so-called field. This is not required for solder resist inks used for industrial boards, but for solder resist inks for consumer boards.
This is because high electrical insulation, high performance such as soldering heat resistance and plating resistance under humid conditions are required, and current solder resist inks for consumer boards do not reach the required performance level.

(Means for Solving the Problems) In order to solve the above problems, the present inventors have produced a novel epoxy acrylate mixture suitable for ultraviolet curable solder resist ink as a result of intensive research. Using this epoxy acrylate mixture, we succeeded in providing an ultraviolet curable resin composition with excellent heat resistance, moisture resistance, solvent resistance, electrical insulation properties, and plating resistance. That is,
The present invention comprises: (1) epoxy acrylate A consisting of a reaction product of an epoxidized product of an acenaphthene-modified phenol resin and (meth)acrylic acid; and a (meth)acrylate monomer B containing an acryloyl group or a methacrylol group in the molecule.
An ultraviolet curable resin composition comprising: and a photosensitizer C.

It is.

(A) Epoxy acrylate used in the present invention is an epoxy compound obtained by reacting epichlorohydrin with an acenaphthene-modified phenolic resin obtained by condensing acenaphthene, phenol, and formaldehyde in the presence of an acidic catalyst. Examples include reactants obtained by adding acrylic acid. The specific manufacturing method of acenaphthene-modified phenolic resin is disclosed in Japanese Patent Application Laid-open No. 1983-
176210, as follows: 1 to 20 moles of phenols per 1 mole of acenaphthene,
Acenaphthene-modified phenols are produced by adding 0.5 to 1.0 times the mole of formaldehyde to the total number of moles of acenaphthene and phenols, then adding an acid catalyst (for example, oxalic acid), heating to reflux temperature, reaction, and purification. Resin is obtained. The epoxidized product of acenaphthene-modified phenolic resin is obtained by the reaction of epichlorohydrin and acenaphthene-modified phenolic resin. The molar ratio of acrylic acid or methacrylic acid to epoxy is between 0.5 and 2.0, preferably between 0.9 and 1.1.
It is. The reaction can be accelerated using a catalyst. Such catalysts are known catalysts such as triethylamine, benzylmethylamine, methyltriethylammonium chloride, and triphenylstibine, and the amount used is based on the weight of the reaction solution.
It is used in an amount of 0.1-20%, preferably 1-5%. It can also be carried out in an organic solvent which is inert under the reaction conditions and which also acts as a viscosity reducing agent. These organic solvents include many suitable solvents such as ketones such as methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, aromatic hydrocarbons such as toluene and xylene, and ethers such as isopropyl ether. be. However, in many cases the reaction is carried out in a reactive diluent that can be carried in a formulation, used as a formulation of a UV curable composition, and incorporated into the composition to be cured. It is preferable to do so. Such a reactive diluent is a (meth)acrylate monomer containing an acryloyl group or a methacryloyl group in the molecule.
(B), examples of which are 2-hydroxyethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, N-vinylpyrrolidone,
Examples include lauryl (meth)acrylate, polyethylene glycol (meth)acrylate, tripropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, styrene, and other monomers.
In addition, these (meth)acrylate monomers B are
If necessary, one type or two or more types can be newly added to the resin composition in an arbitrary ratio.
The reaction temperature is 60-120°C, preferably 70-100°C. It is preferable to add a polymerization inhibitor to prevent polymerization during the reaction, and such polymerization inhibitors include hydroquinone, p-methoxyphenol, 2,4-dimethyl-6-t-butylphenol, α -Nitro-β-naphthol, p-benzoquinone, naphthoquinone thiphenoazine, N-nitrosophenylamine, copper salts and the like. The amount used is usually 0.01% to 1% by weight based on the reaction compound.

As the photosensitizer (C), any known photosensitizer can be used, but those with good storage stability after blending are desirable. Examples of such photosensitizers include benzoin alkyl series such as benzoin ethyl ether and benzoin butyl ether, 2,2-diethoxyacetophenone, and 4'-
Acetophenones such as phenoxy-2,2-dichloroacetophenone, 2-hydroxy-2-methylpropiophenone, 4'-isopropyl-2-
Propiophenones such as hydroxy-2-methylpropiophenone, benzyl dimemethyl ketal 1-hydroxycyclohexyl phenyl ketone and anthraquinones such as 2-ethylanthraquinone, 2-chloroanthraquinone, 2-chlorothioxatone, 2, Examples include thioxanthone photosensitizers such as 4-dimethylthioxanthone. These photosensitizers (C) can be used alone or in a mixture of two or more in any proportion. The amount of component (A) used in the composition of the present invention is preferably 10 to 70% by weight, particularly preferably 15 to 50% by weight of the composition. If the amount of component (A) is less than 10% by weight, curability, hardness, and chemical resistance will decrease, and 70% by weight
Above this, printability and heat-resistant adhesion during solder immersion deteriorate. The amount of component (B) is preferably 25 to 85% by weight, particularly preferably 40 to 80% by weight of the composition.
It's amazing. If the amount of component (B) is less than 25% by weight, printability will be reduced, and if it is more than 85% by weight, curability, water resistance, and chemical resistance will be reduced. The amount of component (C) is
Preferably it is from 0.5 to 15% by weight, particularly preferably from 1 to 8% by weight of the composition. The composition of the present invention is printed by a screen printing method or an offset printing method, and in order to improve printability in that case, extender pigments such as talc, calcium carbonate, alumina, barium sulfate, mica, etc.
Additionally, leveling agents, color pigments, thixotropic agents, thickeners, chelating agents, and the like may be added to the composition of the present invention.

(Example) Hereinafter, the present invention will be specifically explained with reference to Examples. Note that parts in the examples are parts by weight.

Production example of acenaphthene-modified phenolic resin Production example 1 In a flask equipped with a stirrer, a reflux condenser, a thermometer, and a dropping funnel that can be heated with an electric heater from the outside, 94 parts of phenol and 51.3 parts of acenaphthene were heated and melted. Gradually add 81 parts of 37% formalin in which 1 part of oxalic acid is dissolved, then add 4 parts under reflux.
The mixture was allowed to react for a period of time, and then water and unreacted monomers were distilled off by heating under normal pressure. When the water in the flask became low, the temperature began to rise, and 30 parts/hour of water was started to be added dropwise at 130°C. The temperature was increased to 170°C and held at that temperature for 4 hours. 143 parts of yellowish brown acenaphthene-modified phenolic resin was obtained. This material has the following physical properties.

Melting point (°C) 109 Hydroxyl value (mgKOH/g) 348.5 Production example 2 Into the apparatus of Production Example 1, heat and melt 94 parts of phenol and 25.7 parts of acenaphthene, and add 81 parts of 37% formalin in which 1 part of oxalic acid has been dissolved. and 4 in reflux state.
Allowed time to react. The following operations were carried out in the same manner as in Production Example 1. Yellow-brown acenaphthene-modified phenolic resin
120 copies were obtained. This material has the following physical properties.

Melting point (°C) 106 Hydroxylation (mgKOH/g) 352.8 Production example 3 Into the apparatus of Production Example 1, heat and melt 94 parts of phenol and 15.4 parts of acenaphthene, and add 81 parts of 37% formalin in which 1 part of oxalic acid has been dissolved. The mixture was allowed to react under reflux for 4 hours. The following operations were carried out in the same manner as in Production Example 1.
109 parts of yellowish brown acenaphthene-modified phenolic resin was obtained. This material has the following physical properties.

Melting point (°C) 85 Hydroxylization (mgKOH/g) 415.6 Production example of epoxidized acenaphthene-modified phenolic resin Production example 4 Distillation head with heater, stirrer, thermometer, and separator for refluxing to the lower layer of the reactor After heating and dissolving 500 parts of the resin obtained in Production Example 1 and 2507 parts of epichlorohydrin in a reaction vessel equipped with a
Heat to 100°C and add 264 parts of 40% aqueous sodium hydroxide solution. Water and epichlorohydrin distilled from the reaction mixture return only epichlorohydrin to the reaction mixture. After adding 40% aqueous sodium hydroxide solution, unreacted epichlorohydrin is distilled off under reduced pressure, then methyl isobutyl, 700 parts of ketone, and 2100 parts of water are added, stirred and separated, and the aqueous layer is discarded. Add 700 parts of 5% sodium hydroxide aqueous solution to the organic layer and heat at 80°C.
The mixture was stirred for 1 hour. The mixture was cooled to 50°C, the aqueous layer was separated, and the methyl isobutyl ketone was distilled off under reduced pressure. 592 parts of a pale yellow epoxy compound was obtained. This material has the following physical properties.

Epoxy equivalent weight 276.7 Melting point (°C) 88 Production Example 5 500 parts of the resin obtained in Production Example 2 was placed in the apparatus of Production Example 4,
Add 2908 parts of epichlorohydrin and bring the solution to approx.
Heat 40% aqueous sodium hydroxide solution to 360.6 °C.
% was added in the same manner as in Production Example 4, and after distilling epichlorohydrin under reduced pressure, methyl isobutyl and ketone were added.
Add 700 parts and 2100 parts of water, stir, let stand, and separate and discard the aqueous layer. 700 parts of a 5% aqueous sodium hydroxide solution was added to the organic layer, and the mixture was stirred at 80°C for 1 hour. The mixture was cooled to 50°C, the aqueous layer was separated, and the methyl isobutyl ketone was distilled off under reduced pressure. 608 parts of a pale yellow epoxy compound was obtained. This material has the following physical properties.

Epoxy equivalent weight 251.0 Melting point (°C) 67.0 Production example 6 500 parts of the resin obtained in Production example 3 was placed in the apparatus of Production example 4,
Add 3354 parts of epichlorohydrin and bring the solution to approx.
℃, 354 parts of a 40% aqueous sodium hydroxide solution was added in the same manner as in Production Example 4, epichlorohydrin was distilled under reduced pressure, and 700 parts of methyl isobutyl and ketone were added.
1 part, add 2100 parts of water, stir, let stand, and discard the aqueous layer. 700 parts of a 5% aqueous sodium hydroxide solution was added to the organic layer, and the mixture was stirred at 80°C for 1 hour. The mixture was cooled to 50°C, the aqueous layer was separated, and methyl isobutyl ketone was distilled off under reduced pressure. 245 parts of a pale yellow epoxy compound was obtained. This material has the following physical properties.

Epoxy equivalent: 215.7 Melting point (°C): 33.6 Example 1 In a reactor equipped with a stirrer, a temperature controller, a thermometer, and a condenser, 385.7 parts of the epoxy compound obtained in Production Example 4, 94.3 parts of acrylic acid, and 0.4 parts of methoquinone were added. Department,
2.9 parts of triphenylstibine and 320 parts of hydroxypivalyl neopentyl glycol diacrylate were charged, and the reaction was carried out while keeping the temperature of the mixture at 90 to 95°C until the acid value (mgKOH/g) became 1 or less. An epoxy acrylate mixture containing acrylate and hydroxypivalyl neopentyl glycol diacrylate was obtained. This product has the following properties.

Hue (Gardner) 11 Acid value (mgKOH/g) 0.53 Viscosity (25°C, Poise) 1100 Example 2 In the reaction apparatus of Example 1, 315.0 parts of the epoxy compound obtained in Production Example 5, 84.9 parts of acrylic acid, and 0.4 parts of methoquinone were added. 1 part, 2.9 parts of triphenylstibine, and 400.0 parts of trimethylolpropane triacrylate, and while keeping the temperature of the mixture at 90 to 95°C, the reaction was carried out until the acid value (mgKOH/g) became 1 or less to produce epoxy acrylate. An epoxy acrylate mixture containing trimethylolpropane triacrylate and trimethylolpropane triacrylate was obtained. This product has the following properties.

Hue (Gardner) 13 Acid value (mgKOH/g) 0.23 Viscosity (25°C, Poise) 980 Example 3 Into the same reaction apparatus as in Example 1, 395.8 parts of the epoxy compound obtained in Production Example 6, 124.2 parts of acrylic acid, p
- 0.4 parts of methoxyphenol, 2.9 parts of triphenylstibine, 200 parts of trimethylolpropane triacrylate, 200 parts of phenoxyethyl acrylate
Epoxy acrylate containing epoxy acrylate, trimethylolpropane triacrylate, and phenoxyethyl acrylate was prepared by keeping the temperature of the mixture at 90 to 95°C and reacting until the acid value (mgKOH/g) became 1 or less. A mixture was obtained. This product has the following properties.

Hue (Gardner) 13 Acid value (mgKOH/g) 0.92 Viscosity (25°C, Poise) 750 Example 4 2.7 parts of an epoxy acrylate mixture containing the epoxy acrylate obtained in Example 1 and hydroxypivalyl neopentyl glycol diacrylate,
24 parts of trimethylolpropane triacrylate,
Add 17 parts of 2-hydroxyethyl methacrylate, 0.6 parts of cyanine green, 1 part of Modaflow (a leveling agent manufactured by Monsanto), 30 parts of talc, and 3 parts of Irgar Kyuer 6541 (manufactured by Ciba Geigy, a photosensitizer). After uniformly mixing at ~80°C, the mixture was thoroughly kneaded using a three-roll roll (manufactured by Inoue Seisakusho Co., Ltd.) and printed using a screen printing method using a screen with a pattern of 20 mm vertically and 30 mm horizontally. Printed on the copper foil of the wiring board and cured with ultraviolet rays, the pencil hardness of the cured film is 3H, normal,
No blistering or peeling occurred during humidification treatment at 40°C, 90% RH for 4 hours, and solder immersion at 260°C for 20 seconds immediately after immersion in warm water at 80°C for 1 hour. Gold plating was performed on the exposed portions of the conductor, but the cured film of the resist ink did not cause any blistering or peeling.
Further, the insulation resistance was 1×10 ¹³ Ω.

Example 5 3.6 parts of the epoxy acrylate mixture containing epoxy acrylate and trimethylolpropane triacrylate obtained in Example 2, 32 parts of 2-hydroxyethyl methacrylate, cyanine green
Add 0.6 parts of Modaflow (a leveling agent made by Monsanto), 30 parts of talc, and 3 parts of Irgar Kyuer 651 (a photosensitizer made by Ciba Geigy), and knead in the same manner as in Example 1. Printed, hardened area,
The pencil hardness of the cured coating is 3H, normal condition, 40℃90%RH4
Blisters during humidification treatment for hours and solder immersion at 260℃ for 20 seconds immediately after immersion in 80℃ warm water for 1 hour.
No peeling occurred. Gold plating was performed on the exposed conductor parts, but the cured film of the resist ink blistered.
No peeling occurred. Also, the insulation resistance is 1×10 ¹³ Ω.
It was hot.

Example 6 68 parts of the epoxy acrylate mixture containing epoxy acrylate, trimethylolpropane triacrylate, and phenoxyethyl acrylate obtained in Example 3, 0.6 part of cyanine green, 1 part of Modaflow, 30 parts of talc, 2-ethyl anthra Add 1 part of quinone, knead, print, and
When cured, the pencil hardness of the cured film is 3H, normal.
No blistering or peeling occurred during humidification treatment at 40°C, 90% RH for 4 hours, and solder immersion at 260°C for 20 seconds immediately after immersion in warm water at 80°C for 1 hour. Gold plating was performed on the exposed portions of the conductor, but the cured film of the resist ink did not cause any blistering or peeling. or,
The insulation resistance was 1×10 ¹³ Ω.

(Effect of the invention) The ultraviolet curable resin composition of the present invention has heat resistance,
Suitable for UV-curable solder resist inks with excellent moisture resistance, solvent resistance, electrical insulation properties, and plating resistance.

Claims (1)

[Scope of Claims] 1. Epoxy acrylate (A) consisting of a reaction product of an epoxidized product of acenaphthene-modified phenolic resin and (meth)acrylic acid, and a (meth)acrylate monomer (meth) containing an acryloyl group or a methacrylol group in the molecule. An ultraviolet curable resin composition comprising: B) and a photosensitizer (C).