JPH0414151B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a solder resist that is cured by ultraviolet rays and has excellent thick film hardening properties, plating resistance, heat resistance, moisture resistance, solvent resistance, chemical resistance, and electrical insulation properties, and is used as a permanent protective film for printed wiring boards. The present invention relates to an ink composition. In recent years, ultraviolet curable compositions have been widely used for reasons such as resource saving, energy saving, improved workability, and improved productivity. For similar reasons, in the field of printed circuit board processing, various inks such as pattern forming inks, solder resist inks, and marking inks are shifting from conventional thermosetting compositions to ultraviolet curable compositions. Among these, conventional thermosetting compositions for solder resist inks require long heating times, which poses many problems such as workability and deformation of the base material, so we quickly transitioned to UV-curable compositions. did. However, the current applications of this ultraviolet curing composition are limited to so-called consumer substrates used in radios, televisions, etc., and industrial substrates such as computers and control equipment. It has not yet been applied to the field. This means that solder resist inks used for industrial boards have high performance properties that are not required of solder resist inks for consumer boards, such as thick film hardening, plating resistance, high electrical insulation, and resistance to soldering heat under humid conditions. This is because current solder resist inks for consumer boards do not meet the required performance level. In other words, the thickness of the conductor pattern is different between industrial boards and consumer boards, with the thickness of the conductor pattern being 35μ in the case of consumer boards, while the thickness of the conductor pattern on industrial boards is 35μ. It can be over 100μ including the thickness. Therefore, the film thickness of the printed ink is 10 to 20μ on the conductor for a consumer board, and 40 to 50μ on the edge of the conductor.
In the case of industrial boards, the conductor has a thickness of 10 to 20μ, and the edges of the conductor have a thickness of nearly 100 to 120μ. As described above, solder resist inks for industrial substrates are required to have stable curability for thick films. However, at present, if the thick film part is sufficiently cured, the thin film part on the conductor becomes overhardened, which tends to cause poor adhesion or peeling due to heat shock such as soldering heat resistance, and the thin film part cannot be cured properly. Under these conditions, poor curing of thick film parts causes problems with electrical insulation, plating resistance, solder heat resistance under humidified conditions, etc., and a solder resist ink that fully satisfies the performance requirements of industrial board solder resist inks has not yet been developed. do not have. The inventors of the present invention continued to conduct intensive studies to solve the above-mentioned problems, and as a result, the results showed that thick film hardening, plating resistance, heat resistance,
The present inventors have discovered an ultraviolet curable solder resist ink composition with excellent moisture resistance, solvent resistance, and electrical insulation properties, and have completed the present invention. That is, the ultraviolet curable solder resist ink composition of the present invention comprises (A) a (meth)acryloyl group obtained by reacting an epoxy compound of polyhydric phenol or a polyetherified product of polyhydric phenol with (meth)acrylic acid; An unsaturated compound having two or more and (B) general formula () [In the formula, X is a hydrogen atom, a C ₁ to C ₁₂ alkyl group, or

[Formula] (R represents a hydrogen atom or a methyl group), Y is -(
CH ₂ CH ₂ O―) _o or

[Formula] (n is an integer from 1 to 10), Z represents a hydrogen atom or a methyl group] and (C) a photosensitizer as main components. This is an ultraviolet curable solder resist ink composition. Here, (meth)acrylic acid and (meth)acryloyl group include acrylic acid, methacrylic acid, acryloyl group, and methacryloyl group. The unsaturated compound (A) used in the present invention includes:
For example, an unsaturated compound obtained by adding (meth)acrylic acid to an epoxy compound obtained by reacting a polyhydric phenol such as bisphenol A, bisphenol F, or novolak with epichlorohydrin, or an unsaturated compound obtained by adding (meth)acrylic acid to the above polyhydric phenol. Examples include unsaturated compounds obtained by subjecting (meth)acrylic acid to an esterification reaction with a polyetherified polyhydric phenol obtained by adding ethylene oxide, propylene oxide, butylene oxide, ε-caprolactone, or the like. These (A) unsaturated compounds can be used alone or in combination of two or more in any proportion. (B) Monomers include phenoxypolyethoxyethyl (meth)acrylates represented by phenoxyethyl (meth)acrylate, phenoxydiethoxyethyl (meth)acrylate, phenoxyisopropyl (meth)acrylate, and phenoxydiisopropyl (meth)acrylate. Phenoxypolyisopropoxyisopropyl (meth)acrylates represented by propoxyisopropyl (meth)acrylate, p-ethylphenoxyethyl (meth)acrylate, p-butylphenoxydiethoxyethyl (meth)acrylate, p
- Alkylphenoxypolyethoxyethyl (meth)acrylates represented by nonylphenoxydiethoxyethyl (meth)acrylate, p-ethylphenoxyisopropyl (meth)acrylate, p-butylphenoxydiisopropoxyisopropyl ( meth)acrylate, alkylphenoxypolyisopropoxyisopropyl (meth)acrylates represented by p-nonylphenoxydiisopropoxyisopropyl (meth)acrylate, p-cumylphenoxyethyl (meth)acrylate, p- p-cumylphenoxypolyethoxyethyl (meth)acrylates represented by milphenoxydiethoxyethyl (meth)acrylate, p-cumylphenoxyisopropyl (meth)acrylate, p-cumylphenoxydiisopropoxyisopropyl ( p-cumylphenoxypolyisopropoxyisopropyl (meth)acrylates represented by meth)acrylate, p-
p-benzylphenoxypolyethoxyethyl (meth)acrylates represented by benzylphenoxyethyl (meth)acrylate, p-benzylphenoxydiethoxyethyl (meth)acrylate, p-benzylphenoxyisopropyl ( Examples include p-benzylphenoxypolyisopropoxyisopropyl (meth)acrylates represented by meth)acrylate and p-benzylphenoxydiisopropoxyisopropyl(meth)acrylate, but preferably alkylphenoxypolyethoxy Ethyl (meth)acrylates, alkylphenoxypolyisopropoxyisopropyl (meth)acrylates, p-cumylphenoxypolyethoxyethyl (meth)acrylates, p-cumylphenoxypolyisopropoxyisopropyl (meth)acrylate Preferred are p-benzylphenoxypolyethoxyethyl (meth)acrylates, and p-benzylphenoxyisopropoxyisopropyl (meth)acrylates. The number of repeating ethoxy groups and isopropoxy groups in the polyethoxy group and polyisopropoxy group in the above monomers is preferably 0 to 10, more preferably 1 to 5. If the number of repetitions exceeds 10, the water resistance and chemical resistance of the composition will drop significantly, which is not preferable. These (B) monomers are 1
A species or two or more species can be mixed in any ratio. (C) As the photosensitizer, any known photosensitizer can be used, but it is desirable that it has good storage stability after being blended. Examples of such photosensitizers include benzoin alkyl ether photosensitizers such as benzoin ethyl ether and benzoin isobutyl ether, 2,2-diethoxyacetophenone, and 4'-phenoxy-2,2-dichloroacetate. Acetophenone photosensitizers such as phenone,
2-hydroxy-2-methylpropiophenone,
Propiophenone photosensitizers such as 4'-isopropyl-2-hydroxy-2-methylpropiophenone; anthraquinone photosensitizers such as 2-ethylanthraquinone, 2-t-butylanthraquinone, and 2-chloroanthraquinone; , thioxanthone photosensitizers such as 2-chlorothioxanthone, 2,4-diisopropylthioxanthone, and 2,4-dimethylthioxanthone, and benzyl ketal photosensitizers such as benzyl dimethyl ketal. These photosensitizers 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 20 to 80% by weight, particularly preferably 35% by weight of the composition.
~75% by weight is desirable. If the amount of component (A) is less than 20% by weight, curability, hardness, and chemical resistance will be reduced, and if it is more than 80% by weight, printability and heat-resistant adhesion during solder immersion will be reduced. The amount of component (B) is preferably 5 to 70% by weight, particularly preferably 10 to 50% by weight of the composition.
It's amazing. If the amount of component (B) is less than 5% by weight, curing stability with respect to film thickness cannot be obtained, and the effects of the present invention, such as a decrease in heat resistance during solder immersion under humidified conditions, cannot be obtained. If it exceeds 70% by weight, curability, water resistance, and chemical resistance decrease. The amount of component (C) is preferably 0.5 to 15% by weight, particularly preferably 1 to 8% by weight of the composition. If component (C) is less than 0.5% by weight, the curing property by ultraviolet rays will be significantly reduced, and if it is more than 15% by weight, no significant improvement in performance will be observed, making it impractical from a cost standpoint. The composition of the present invention may further contain unsaturated compounds other than the unsaturated compound as component (A) and the monomer as component (B). Examples of such unsaturated compounds include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, benzyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dicyclopentenyl (meth)acrylate, Dicyclopentenyloxyethyl (meth)acrylate, (meth)acryloxyethyl phosphate,
Cellosolve (meth)acrylate, butyl cellosolve (meth)acrylate, carbitol (meth)acrylate, butyl carbitol (meth)
acrylate, benzyl (meth)acrylate,
Monofunctional unsaturated compounds such as (meth)acrylic acid adducts of phenyl glycidyl ether, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate Acrylate, neopentyl glycol di(meth)acrylate, 1,
4-butanediol di(meth)acrylate,
Difunctional unsaturated compounds such as 1,6-hexanediol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, bis[(meth)acryloxyethyl] phosphate, trimethylolethane tri(meth)acrylate , trimethylolpropane tri(meth)acrylate, tris(2-hydroxyethyl)isocyanuric acid(meth)acrylate, glycerin tri(meth)acrylate
Polyfunctional unsaturated compounds such as acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane trioxyethyl(meth)acrylate, etc. may be mentioned, but 50 of the compositions of the present invention include It is not preferable to use more than % by weight because the balance of curability, chemical resistance, heat resistance, etc. will be lost. 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, and mica, and leveling agents, Colored pigments, thixotropic agents, thickeners, chelating agents, etc. may be added to the composition of the present invention. When the ink composition of the present invention is put into practical use, a desired portion is printed on the surface of a laminate plate on which a conductive pattern is formed by etching or plating, by a method such as screen printing or offset printing, and then ultraviolet rays are irradiated to form a permanent protective film. Form. A high-pressure mercury lamp or a metal halide lamp of 50 to 200 W/cm is usually used for UV irradiation, and curing can be completed within a short time of 20 seconds. Example 1 Epikote as bisphenol A type epoxy
828 (manufactured by Ciel), 72 g of acrylic acid, 1 g of dimethylamine hydrochloride as a reaction catalyst, and 0.2 g of hydroquinone as a polymerization inhibitor were placed in a flask equipped with a stirring device, and the mixture was allowed to react at 100°C until the acid value reached 0.1 or less. Unsaturated compound A-1 was obtained. 40 parts of the above unsaturated compound A-1, 40 parts of p-butylphenoxyethyl acrylate as the (B) monomer
(C) 8 parts of benzyl dimethyl ketal as a photosensitizer, 16 parts of trimethylolpropane triacrylate as other unsaturated compounds, 35 parts of talc as an extender, 2 parts of Erosil as a thixotropic agent, and a colored pigment. as phthalocyanine green
0.3 part was added and kneaded using three rolls to prepare an ultraviolet curing solder resist ink. A desired pattern was printed using the above resist ink on a laminate plate having a conductor pattern with a thickness of 100 μm by screen printing, and the above resist ink was cured by irradiating ultraviolet rays with an 80 W/cm high pressure mercury lamp. The time required for curing was 10 seconds. The cured film thickness of the above ink was 15μ on the conductor and 110μ on the conductor edge. The pencil hardness of the cured coating is 4H, normal condition, 90% at 40℃
No blistering or peeling occurred during humidification treatment at RH for 4 hours and solder immersion at 260°C for 20 seconds immediately after 1 hour immersion in 80°C warm water. Gold plating was performed on the exposed portions of the conductor, but no blistering or peeling occurred on the cured film of the resist ink. Also, JIS
The insulation resistance of Z3197 was 2×10 ¹³ Ω. Comparative Example 1 An ultraviolet solder resist ink was prepared in the same manner as in Example 1 except that monomer (B) was replaced with benzyl acrylate. This ink was printed on a laminate plate on which a 100 μm conductor pattern was formed in the same manner as in Example 1, and then cured. The cured film thickness of this ink is 16μm on the conductor.
It was 106 μm at the conductor edge. The pencil hardness of the cured coating is 2H, normal condition 40℃90%RH4
Blisters occurred on the conductor during humidification treatment for several hours and immersion in solder at 260°C for 20 seconds immediately after immersion in warm water at 80°C for 1 hour. In addition, in the gold plating of the exposed conductor part, a phenomenon of gold plating occurring between the conductor on the conductor and the cured film occurred. Example 2 Epikote as bisphenol F type epoxy
807 (manufactured by Ciel), 72 g of acrylic acid, 0.5 g of 2,4,6-tris(dimethylaminomethyl)phenol as a reaction catalyst, and 0.2 g of hydroquinone as a polymerization inhibitor were placed in a flask equipped with a stirring device.
The reaction was carried out at 100°C until the acid value became 0.1 or less to obtain unsaturated compound A-2. 70 parts of the above unsaturated compound A-2, 20 parts of p-cumylphenoxyethyl acrylate as the (B) monomer
(C) 5 parts of 2-t-butylanthraquinone as a photosensitizer, 5 parts of hydroxyethyl methacrylate as other unsaturated compounds, 20 parts of talc as an extender, 10 parts of alumina, and Erosil as a thixotropic agent. 1 part and 0.3 part of phthalocyanine green as a color pigment were added and kneaded and dispersed using a sand mill to prepare an ultraviolet curing solder resist ink. A desired pattern was printed using the above resist ink on a 100 μ thick conductor patterned laminate by screen printing, and the above resist ink was cured by irradiation with a 100 W/cm high pressure mercury lamp. The time required for curing was 9 seconds. The cured film thickness of the above ink is 14μ on the conductor, 100μ on the conductor edge, and the pencil hardness of the cured film is 4H, under normal conditions, after humidification treatment at 40℃, 90%RH for 4 hours, and immediately after 1 hour immersion in 80℃ warm water at 260℃, 20℃. No blistering or peeling occurred during solder immersion for seconds. Gold plating was performed on the exposed conductor portions, but no blistering or peeling of the cured resist ink film occurred. Furthermore, the insulation resistance according to JIS Z3197 was 1×10 ¹³ Ω. Example 3 175 g of Epicote 154 (manufactured by Ciel) as a novolac epoxy and 72 g of acrylic acid were reacted in the same manner as in Example 1 to obtain unsaturated compound A-3. 35 parts of the above unsaturated compound A-3, (B) 30 parts of p-benzylphenoxyisopropyl acrylate as a monomer, (C) 2-hydroxy- as a photosensitizer.
5 parts of 2-methylpropiophenone, 30 parts of 1,6-hexanediol diacrylate as other unsaturated compounds, and talc as an extender.
40 parts, barium sulfate 5 parts, Erosyl 1 part as a thixotropic agent, phthalocyanine green as a coloring pigment.
0.5 part was added and kneaded using three rolls to prepare an ultraviolet curing solder resist ink. A desired pattern was printed using the above resist ink by screen printing on a laminate plate on which a conductor pattern with a thickness of 100 μm was formed, and the above resist ink was cured by irradiation with ultraviolet rays using a 120 W/cm metal halide lamp. The time required for curing was 8 seconds. The cured film thickness of the ink was 16μ on the conductor and 115μ on the conductor edge. The pencil hardness of the cured coating film was 5H, and no blistering or peeling occurred during normal conditions, 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 no blistering or peeling occurred on the cured film of the resist ink. Also, the insulation resistance according to JIS Z3197 is 1×10 ¹³
It was Ω. Example 4 Epikote as bisphenol A type epoxy
1001 (manufactured by Ciel) 450g, acrylic acid 72g, toluene 200g as a solvent, 2,4, as a reaction catalyst
6-tris(dimethylaminomethyl)phenol
After reacting 0.5 g of hydroquinone as a polymerization inhibitor and 0.4 g of hydroquinone as a polymerization inhibitor in the same manner as in Example 1, removal of toluene was performed to obtain unsaturated compound A-4. 20 parts of the above unsaturated compound A-4, 20 parts of the unsaturated compound A-2 obtained in Example 2, (B) 30 parts of p-cumylphenoxydiethoxyethyl acrylate as a monomer, (C) Photointensity As a sensitizer, 1 part diisopropylthioxanthone, 1 part benzyl dimethyl ketal
10 parts of 2-hydroxypropyl methacrylate and 18 parts of neopentyl glycol diacrylate as other unsaturated compounds, 30 parts of talc as an extender, 10 parts of mica powder, 0.5 part of Erosil as a thixotropic agent, and 0.5 parts of a coloring pigment. 0.4 part of phthalocyanine green was added and kneaded using three rolls to prepare an ultraviolet curing solder resist ink. A desired pattern was printed using the above resist ink on a laminate plate having a conductor pattern with a thickness of 100 μm by screen printing, and the above resist ink was cured by irradiation with ultraviolet rays using a 100 W/cm metal halide lamp. The time required for curing was 8 seconds. The cured film thickness of the above ink was 14μ on the conductor and 110μ on the conductor edge. The pencil hardness of the cured coating film was 5H, and no blistering or peeling occurred during normal conditions, 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 no blistering or peeling occurred on the cured film of the resist ink. Furthermore, the insulation resistance according to JIS Z3197 was 2×10 ¹³ Ω. Example 5 410 g of polyetherified bisphenol A, in which 4 moles of ethylene oxide was added to 1 mole of bisphenol A, and 144 g of acrylic acid were added to toluene.
200g, p-toluenesulfonic acid as reaction catalyst
0.5 g and 0.4 g of hydroquinone as a polymerization inhibitor were placed in a flask equipped with a stirrer to carry out an esterification reaction at 100°C. After the reaction was completed, toluene was removed to obtain unsaturated compound A-5. 30 parts of the above unsaturated compound A-5, 20 parts of the unsaturated compound A-3 obtained in Example 3, (B) 20 parts of p-benzylphenoxydiethoxymethyl methacrylate as a monomer, (C) light As a sensitizer, 3 parts of t-butylanthraquinone, 4'-phenoxy-2,2-
2 parts of dichloroacetophenone, dipentaerythritol hexaacrylate as other monomers
15 parts of 2-hydroxyethyl methacrylate and 10 parts of 2-hydroxyethyl methacrylate were mixed to prepare an ultraviolet curing solder resist ink in the same manner as in Example 1. A desired pattern was printed using the above resist ink on a laminate plate having a conductor pattern with a thickness of 100 μm by screen printing, and the above resist ink was cured by irradiation with ultraviolet rays using a 100 W/cm high pressure mercury lamp. The time required for curing was 11 seconds. The cured film thickness of the ink was 16μ on the conductor and 108μ on the conductor edge. The pencil hardness of the cured coating is 5H, normal condition, 90% at 40℃
No blistering or peeling occurred during humidification treatment at RH for 4 hours and solder immersion at 260°C for 20 seconds immediately after 1 hour immersion in 80°C warm water. Gold plating was performed on the exposed portions of the conductor, but no blistering or peeling occurred on the cured film of the resist ink. Also, JIS
The insulation resistance of Z3197 was 2×10 ¹³ Ω. Example 6 286 g of polyetherified bisphenol F with 2 moles of propylene oxide added to 1 mole of bisphenol F, 172 g of methacrylic acid and 150 g of toluene, 0.3 g of p-toluenesulfonic acid as a reaction catalyst, and 0.4 g of hydroquinone as a polymerization inhibitor. The mixture was placed in a flask equipped with a stirrer and subjected to an esterification reaction at 100°C. After the reaction was completed, toluene was removed to obtain unsaturated compound A-6. 35 parts of the above unsaturated compound A-6, (B) 15 parts of p-ethylphenoxydipropoxypropyl methacrylate as a monomer, (C) 2 parts of 2-hydroxy-2-methylpropiophenone as a photosensitizer, diisopropyl 2 parts of thioxanthone, 15 parts of dipentaerythritol hexaacrylate, and neopentyl glycol diacrylate as other monomers.
A UV curable resist ink was prepared in the same manner as in Example 1 by mixing 31 parts. A desired pattern was printed using the above resist ink on a laminate plate having a 100 μm thick conductor pattern formed thereon by screen printing, and the above resist ink was cured by irradiation with ultraviolet rays using a 160 W/cm high pressure mercury lamp. The time required for curing was 7 seconds. The cured film thickness of the ink was 23μ on the conductor and 120μ on the conductor edge. The pencil hardness of the cured coating film was 5H, and no blistering or peeling occurred during normal conditions, 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 no blistering or peeling occurred on the cured film of the resist ink. Furthermore, the insulation resistance according to JIS Z3197 was 1×10 ¹³ Ω.

Claims (1)

[Scope of Claims] 1 (A) An unsaturated compound having two or more (meth)acrylic groups obtained by reacting an epoxy compound of polyhydric phenol or a polyether compound of polyhydric phenol with (meth)acrylic acid. and (B) general formula () (In the formula, X is a hydrogen atom, a C ₁ to C ₁₂ alkyl group, or (R represents a hydrogen atom or a methyl group),
Y is - (CH ₂ CH ₂ O -) _o or (n represents an integer from 1 to 10), Z represents a hydrogen atom or a methyl group, respectively) and (C) a photosensitizer as main components. Cured solder resist ink composition.