JPS63230705A - Ultraviolet-curable resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which can cure in a thick film and excellent in soldering heat resistance, moisture resistance, adhesiveness, etc., by mixing a photocurable prepolymer with a photopolymerizable monomer, a photopolymerization initiator, a heat polymerization initiator and an epoxy group-containing silane coupling agent. CONSTITUTION:20-80wt.% total of 95-10wt.% photopolymerizable prepolymer (A) of an MW of 500-5,000 [e.g., di(meth)acrylate of bisphenol A/ethylene oxide adduct] and 5-90wt.% photopolymerizable compound (B) (e.g., styrene) is mixed with 0.1-10wt.% photopolymerization initiator (C) (e.g., benzil dimethyl ketal), 0.01-10wt.% heat polymerization initiator (D) (e.g. di-t-butyl peroxide), 0.0-10wt.% epoxy group-containing silane coupling agent (E) (e.g., gamma- glycidoxypropyltrimethoxysilane) and, optionally, 1-60wt.% inorganic filler (F) (e.g., CaCO3), 0.1-15wt.% coloring pigment (G) (e.g., TiO2). etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ultraviolet curable resin composition, particularly an ultraviolet curable solder resist ink used in the manufacture of printed wiring boards.

(Conventional technology) Inks using thermosetting resins such as epoxy resins and melamine resins are used as solder resist inks to protect and insulate conductor circuits on printed wiring boards and to prevent solder bridging during the mounting process. However, since these are heat-curing methods, there are serious problems such as ■long curing time, ■high energy consumption, ■difficult to automate and save labor, and ■significant environmental pollution caused by solvents. I had a problem. Against this background, UV-curable solder resist inks, which are solvent-free, fast-curing, and highly productive, have come into widespread use. However, the applications in which UV-curable solder resist inks are currently used are limited to the field of consumer circuit boards used in televisions, radios, stereos, etc. However, at present, it has not yet been applied to the field of industrial substrates that require high reliability. In other words, with the recent shift to a highly information-oriented society based on computers and communications, there has been an extremely strong trend toward making electronic devices smaller and lighter, so-called "light, thin, short, and small." Therefore, printed wiring boards, which can be called the heart of these systems, are rapidly becoming more complex, finer, and denser.
There is an increasing demand for higher reliability of printed wiring boards.

However, conventional ultraviolet-curing solder resist inks are opaque inks containing inorganic fillers and/or blue pigments, so they cannot be cured in thick films by ultraviolet light (e.g.
50 μm or more) is not possible.

■ Advanced soldering heat resistance (for example, soldering at a temperature of 270°
C or higher) reliability is low.

■ High moisture resistance after soldering (for example, after soldering,
As mentioned above, it was limited to the field of so-called consumer PCBs due to its shortcomings such as extremely low reliability with respect to extremely severe pressure resistance tests (exposure to water vapor at 120°C and 2 atmospheres). It was because of this.

Naturally, various attempts have been made to overcome the above drawbacks. For example, in order to eliminate the drawback of (1) above, a thermal polymerization initiator, such as an organic peroxide or an azo compound, is added to an ultraviolet curable solder resist ink composition, and these are used to accelerate the curing of the photopolymerization initiator. A method has been used to harden thick film portions by acting as an agent. However, in this method, a thermal polymerization initiator,
In other words, when diacyl peroxide, peroxydicarbonate, peroxy ester, or azo compound is used as the peroxide in the peroxide, carbon dioxide gas or nitrogen gas is generated from radicals generated by ultraviolet rays or heat. Pinholes remain in the cured coating film, and as a result, soldering heat resistance, moisture resistance, etc. are significantly reduced.

In this way, current UV-curable solder resist inks have not yet reached the performance level required for solder resist inks for industrial boards, and the development of solder resist inks that can be applied to industrial boards is essential for printed wiring. This was strongly requested by the board industry.

(Problems to be Solved by the Invention) In other words, the present invention provides an ultraviolet curable solder resist ink used in the manufacture of printed wiring boards that is capable of thick film curing and has high soldering heat resistance and moisture resistance. The present invention provides an ultraviolet curable solder resist ink composition that has excellent properties such as properties and high reliability.

(Means for solving the gap) As a result of intensive research to solve the above problems, the present inventors found that in a system in which a thermal polymerization initiator and an epoxy group-containing silane coupling agent coexist, The inventors have found that the above problems can be solved and have arrived at the present invention. That is, the present invention provides a photopolymerizable prepolymer (I), a photopolymerizable monomer (I
I), photopolymerization initiator (III), thermal polymerization initiator (IV)
and an epoxy group-containing silane coupling agent (V).

The photopolymerizable prepolymer (I) used in the present invention is (
i) Ethylene nioxide and/or propylene oxide of bisphenol A are adducts of bisphenol A and alkylene oxide adducts such as di(meth)acrylate (acrylate and methacrylate are abbreviated in this way. The same applies hereinafter) of hydrogenated bisphenol A. Di(meth)acrylate of alkylene oxide adduct of hydrogenated bisphenol A such as ethylene oxide or/and propylene oxide adduct, terminal incyanate group obtained by reacting GO diisocyanate compound with two or more alcoholic hydroxyl group-containing compounds in advance Urethane-modified di(meth)acrylate containing two (meth)acryloyloxy groups in the molecule obtained by further reacting the containing compound with (meth)acrylate containing an alcoholic hydroxyl group, Git) 2 in the molecule Epoxy di(meth)acrylate obtained by reacting the above compound having an epoxy group with acrylic acid or methacrylic acid, acrylic acid or methacrylic acid as the carboxylic acid component, and dihydric carboxylic acid and alcohol component as the polyhydric carboxylic acid component. Oligoester di(meth) obtained by reacting with the above polyhydric alcohols
Typical examples include acrylate, and the molecular weight of these prepolymers is usually about 500 to about 5,000, and one type or two or more types may be used in combination.

The photopolymerizable compound (II) used in the present invention is a compound having one or more polymerizable double bonds in its molecule, such as (i) styrene, α-methylstyrene, chlorostyrene, etc. Styrenic compound, G8 methyl (meth)acrylate, ethyl (meth)acrylate, n- and i-propyl (meth)acryle)N n-15e C
Alkyl (meth)acrylates such as - and t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, GiO cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate Alicyclic (meth)acrylates such as acrylates, (Jv
) Mono( meth)acrylate (v) ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neobentyl glycol di(meth)acrylate), 1
．． 8-hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate of tri or higher, polyethylene glycol di(meth)acrylate of tri or higher polyoxyalkylene glycol di(meth)acrylate, (va)limethylolpropane tri(meth)acrylate, nolimethylolpropane tetra(meth)acrylate, trimethylolethane tri(meth)acrylate, etc.
Acrylate, glycerin tri(meth)acrylate,
polyfunctional (meth)acrylates such as pentaerythritol tetra(meth)acrylate, dipentaerythritol penta and/or hexa(meth)acrylate;
~ Allyl compounds such as diallyl phthalate and triallyl cyanurate, tris(meth)acryloyloxybutyl isocyanurate such as Q-tris(meth)acryloyloxyethyl isocyanurate, tris(meth)acryloyloxypropyl isocyanurate, and tris(meth)acryloyloxybutyl isocyanurate. ) acryloyloxyalkyl isocyanurate, ni) hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, diethylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tripropylene Representative examples include hydroxyalkyl (meth)acrylates such as glycol mono(meth)acrylate, glycerin mono(meth)acrylate, glycerin di(meth)acrylate, and trimethylolpropane di(meth)acrylate.

The compounding ratio of the photopolymerizable prepolymer (I) and the photopolymerizable monomer (It) used in the present invention is (I): (n) ~
95:5 to 10:90 (weight ratio), preferably 80:
20-15:80 (gravity n ratio).

The proportion of the photopolymerizable prepolymer (I) and the photopolymerizable monomer (II) in the ultraviolet curable resin composition of the present invention is 20% of the total composition of (I) and (II). % to 80% by weight.

The photoinitiator (III) used in the present invention is a compound that promotes the photopolymerization reaction, and there are no particular limitations on the photoinitiator (III), such as benzyl dimethyl ketal tars, benzoin methyl ether, benzoin ethyl ether, benzoin-
Benzoin such as j-propyl ether, benzoin, d-methylbenzoin! , 9.10-anthraquinone,
-Anthraquinones such as chloranthraquinone, 2-chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, and 2-amylanthraquinone; benzophenones such as benzophenone, p-chlorobenzophenone, and p-dimethylaminobenzophenone;
2-hydroxy-2-methylpropiophenone, 1-(
Propiophenones such as 4-isopropylphenyl)-2-hydroxy-2-methylpropiophenone, suberones such as dibenzosuberone, sulfur-containing compounds such as diphenyl disulfide, tetramethylthiuram disulfide, and thioxanthone, methylene blue, and eosin. , dyes such as fluorescein, etc. alone or 2FI! The above are used in combination.

The amount of photoinitiator (III) is 0 in the resin composition of the present invention.
．． It is 1 to 10% by weight.

The thermal polymerization initiator NV) is an organic peroxide that does not generate carbon dioxide or nitrogen gas, preferably an alkyl peroxide. Examples of the dialkyl peroxide include di-t-butyl peroxide and t-butyl cumin. Luperoxide, dicumyl peroxide, α, α
'-bis(t-butylperoxy-m-isopropyl)
Benzophenone, 2,5-dimethyl-2,5-di(t-
butylperoxy)hexane, 2,5-dimethyl-2,
Examples include 5-di(t-butylperoxy)hexane-3. These compounds may be used alone or in combination of two or more. These compounds may be used as they are, or may be used as a solution dissolved in an organic solvent such as toluene or xylene. The blending amount thereof is 0.01 to 10% by weight in the resin composition of the present invention.

Using epoxy foundation as a silane coupling agent (V),
For example, γ-glycidoxypropyltrimethoxine run,
γ-glycidoxypropyltriethoxysilane, β-(
3,4-epoxycyclohexyl)ethyltrimethoxysilane, β-(3゜4-epoxycyclohexyl)ethyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyljethoxysilane, β- (3,4-epoxycyclohexyl)ethylmethyljethoxysilane, β-(3,4-
Examples include epoxycyclohexyl)ethylmethyljethoxysilane, epoxy-modified polysiloxane shown by the following structure, and the like.

These compounds may be used alone or in combination of two or more. These compounds may be used as they are, or they may be hydrolyzed by adding water and heating in an organic solvent such as alcohol, ketone, or ether. The blending amount thereof is 0.01 to 10% by weight in the resin composition of the present invention.

When the resin composition of the present invention does not contain only a thermal polymerization initiator (mV), thick film curing (for example, 70 μm or more)
Not only is it impossible, but the high degree of solder heat resistance and moisture resistance are insufficient. Furthermore, if the epoxy base is not mixed with only the silane coupling agent (V), thick film curing is possible, but high soldering heat resistance and moisture resistance are insufficient.

Typical examples of inorganic fillers used as necessary in the present invention include calcium carbonate, barium sulfate, clay, alumina, talc, kaolin, silica powder, diatomaceous earth, and bentonite. 1 to 60% by weight of the resin composition, preferably 10 to 50% by weight
It is.

Known inorganic and organic pigments such as titanium dioxide, carbon black, phthalocyanine blue, and phthalocyanine green are used as blue pigments used as necessary in the resin composition of the present invention, and the blending amount thereof is usually determined according to the present invention. It is 0.1 to 15% by weight of the resin composition.

The ultraviolet curable resin composition of the present invention contains hydroquinone,
Known thermal polymerization inhibitors such as hydroquinone monomethyl ether, t-butylcatechol, p-benzoquinone, 2.5-t-butyl-hydroquinone, and phenothiazine;
It is used in combination with additives such as surface smoothing agents and antifoaming agents.

The ultraviolet curable resin composition of the present invention is applied or printed on a printed circuit board using a conventional coating method or printing method, and then cured by ultraviolet irradiation or by heating after ultraviolet irradiation. As the ultraviolet ray generation source, a chemical lamp, a low pressure mercury lamp, a high pressure mercury lamp, a carbon arc lamp, a Canon lamp, a metal halide lamp, etc. are used.

Further, as a heating source, hot air, a nichrome heater wire, an infrared lamp, a far infrared heater, etc. are used.

(Examples) In order to explain the present invention more specifically, Examples are given below, but of course the present invention is not limited to these Examples in any way.

Example 1 Bisepoxy acrylate of bisphenol A 15m
ff1 part trimethylolpropane triacrylate
2S1.6-hexanediol diacrylate
102-hydroxyethyl methacrylate 1
52-Ethylanthraquinone
1.5t-butylcumyl peroxide
1γ-glycidoxypropyltrimethoxysilane
1 talc
30 surface smoothing agent
0.5 phthalocyanine green
1 After mixing the above raw materials, they were uniformly kneaded using three rolls to obtain an ultraviolet curable solder resist ink composition using the resin composition of the present invention. Using the obtained ink composition, a glass-reinforced epoxy resin steel-clad laminate (copper foil thickness 35 μm
) on a comb-shaped electrode (JIS Z-3197) using a screen printing method, and then irradiated with ultraviolet rays for 20 seconds at a distance of 150 cm under an N80 w/c high pressure mercury lamp to a thickness of 2
Cured films of 0 μm and 70 μm were obtained. Table 1 shows the measurement results of various properties of the cured film and the storage stability of the ink composition.

Example 2 Ultraviolet curing was carried out in the same manner as in Example 1 except that β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane was used in place of the γ-glycidoxypropyltrimethoxysilane component in Example 1. A mold solder resist ink composition was obtained.

Using the obtained ink composition, in the same manner as in Example 1,
A cured film was obtained. Table 1 shows the measurement results of various properties of the cured film.

Example 3 Bisepoxy acrylate of bisphenol A 10-fold all-phenol novolac type epoxy acrylate 1
0 trimethylolpropane triacrylate 15
Diethylene glycol dimethacrylate 52
-Hydroxyethyl methacrylate 15 Benzine methyl ketal 12-Ethylanthraquinone l Dicumyl peroxide 0.5β-(3
,4-epoxycyclohexyl)ethyltrimethoxysilane 2 Talc
39 Surface smoothing agent
0.5 Phthalocyanine Green 1 The above raw materials were mixed and kneaded uniformly using three rolls to obtain an ink composition for an ultraviolet curable solder/resist using the resin composition of the present invention.

A cured film was obtained in the same manner as in Example 1 using the obtained ink composition. Table 1 shows the measurement results of various properties of the film.

Example 4 In Example 3, everything was carried out in the same manner as in Example 3, except that γ-glycidoxyprobyltrimethoxysilane was used instead of the β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane component. UV curing solder
A resist ink composition was obtained.

A cured film was obtained in the same manner as in Example 1 using the obtained ink composition. Table 1 shows the measurement results of various properties of the cured film.

Comparative Example 1 An ultraviolet curable ink composition was obtained in the same manner as in Example 1 except that t-butylcumyl peroxide was not added.

A cured film was obtained in the same manner as in Example 1 using the obtained ink composition. The measurement results of various properties of the cured film are also shown in Table 1.

Comparative Example 2 In the same manner as in Example 1 except that γ-glycidoxypropyltrimethoxine oran was not added,
An ultraviolet curable ink composition was obtained.

A cured film was obtained in the same manner as in Example 1 using the obtained ink composition. The measurement results of various properties of the cured film are also shown in Table 1.

Comparative Example 3 An ultraviolet curable ink composition was obtained in the same manner as in Example 1 except that vinyltrimethoxysilane was used in place of the γ-glycidoxypropyltrimethoxysilane component.

A cured film was obtained in the same manner as in Example 1 using the obtained ink composition. The measurement results of various properties of the cured film are also shown in Table 1.

Comparative Example 4 An ultraviolet curable ink composition was obtained in the same manner as in Example 1 except that 3-aminopropyltriethoxysilane was used in place of the γ-glycidoxypropyltrimethoxysilane component. Ta.

A cured film was obtained in the same manner as in Example 1 using the obtained ink composition. The measurement results of various properties of the cured film are also shown in Table 1.

Example 5 An ultraviolet curable ink composition was obtained in the same manner as in Example 3 except that cumene hydroperoxide was used instead of the dicumyl peroxide component.

A cured film was obtained in the same manner as in Example 1 using the obtained ink composition. Table 1 shows the measurement results of various properties of the cured film and the storage stability of the ink composition.

Margins below (Effects of the Invention) When the ultraviolet curable resin composition of the present invention is used in combination with a thermal polymerization initiator and an epoxy-containing silane coupling agent, for example as a solder resist ink, (1) It has extremely high soldering heat resistance of 270'C or higher.

■ Even after soldering, it has a high degree of moisture resistance that can withstand the extremely harsh pressure test of exposing it to water vapor at 120°C and 2 atmospheres.

(3) Excellent contactability.

(Φ Excellent solvent resistance.

) The ink has excellent storage stability.

Not only can it be used as a binder for solder, resist, and ink for industrial boards, but it can also be used as a binder for insulating paste, overlay ink, marking ink, etc., as well as for coating agents, paints, etc. Can be used for any purpose. As a base material, glass, metal, plastic, ceramic, etc. can also be used.

Claims (1)

[Claims] Photopolymerizable prepolymer (I), photopolymerizable monomer (II)
), a photopolymerization initiator (III), a thermal polymerization initiator (IV), and an epoxy group-containing silane cupping agent (V).