JPH11335441A - Photocation-polymerizable epoxy resin-based solid composition and article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photocation-polymerizable epoxy resin-based solid composition having excellent storage stability and coating film smoothness, free from a smell and having excellent reactivity by compounding a specific epoxy resin and a photocation polymerization initiator. SOLUTION: This photocation-polymerizable epoxy resin-based solid composition comprises (A) an epoxy resin comprising (i) 5-100 wt.%, preferably 10-100 wt.% more preferably 20-100 wt.%, of an epoxy resin of formula I (R1 and R2 are each H, a 1-6C alkyl or a halogen) and, if necessary, (ii) another epoxy resin, (B) a photocation polymerization initiator and, if necessary, (C) a curing agent, a chain transfer agent, a sensitizer, a colorant, etc. The component B is preferably a compound of formula II [R3 and R4 are each H, an alkyl, a halogen, a hydroxyalkyloxy or an alkoxy; R5 and R6 are each H, a halogen or an alkyl; X is SbF6 , PF6 , AsF6 , BH4 or B(C6 F5 )4 ], a compound of formula III (R7 and R8 are each R3 or R4 ; R9 is R5 or R6 ), etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin-based solid composition which is cured by irradiation with ultraviolet rays, and more particularly to an epoxy resin-based solid composition which has excellent storage stability and gives a smooth coating film.

[0002]

2. Description of the Related Art An epoxy resin-based solid composition represented by a powder coating is usually cured by heat, and its curing temperature is 15 ° C.
It cannot be used when applying an epoxy resin-based solid composition to a substrate having a high temperature of 0 ° C. or higher and a low heat resistance temperature.

In order to perform low-temperature curing or short-time curing, it is necessary to incorporate a large amount of a curing accelerator or use a polyfunctional epoxy resin. However, in such a case, the gelation proceeds during storage, and the coating film becomes rough or the physical properties are deteriorated, which causes a problem in storage stability. In addition, as a method for measuring the low-temperature rapid curing of an epoxy resin-based powder coating, a method using an amine-based curing agent is known. However, the amine-based curing agent also has a problem that the storage stability of the coating is reduced. doing. As a method of increasing the storage stability, a method of microencapsulating a curing accelerator is known, but the capsule is broken during kneading and the accelerator is eluted, and the storage stability is impaired or, conversely, during curing. However, there is a problem that the capsule is not broken and the reactivity is lowered.

In order to form a smooth coating film at the time of curing at a low temperature, it is necessary to use a resin having a low melt viscosity. However, such an epoxy resin has a low softening point and causes blocking during storage. Does not stand use.

In order to solve these problems caused by thermal curing, a cationic photopolymerization method using ultraviolet light has been proposed. If the composition is curable by the cationic photopolymerization method, there is no problem in storage stability as long as it is stored in a dark place, and the base material to be applied has heat resistance at a temperature at which the composition can be melted to form a coating film. It is enough. Therefore, it becomes possible to apply even to a material which has to rely on a solvent-based paint, and there is no environmental pollution by an organic solvent, and workability is improved. In addition, since high-temperature baking is not required, energy cost can be reduced, and curing is performed at a level of several seconds to several minutes, so that productivity is excellent.

[0006] Epoxy resin compositions which cure by photocationic polymerization include epoxy resins such as alicyclic epoxy resins, bisphenol A epoxy resins and novolak epoxy resins, onium salts and photosensitive aromatic diazonium salts. Those containing a polymerization initiator and other additives are well known.

[0007] As a solid epoxy resin composition, for example, JP-A-7-252344 discloses an epoxy resin mixture having a glass transition temperature (T _g ) of 35 ° C. or more, a polyfunctional nucleophilic chain transfer agent, and a sulfonium. Compounds containing salt have been proposed. However, in this case, since bisphenol A type epoxy resin is a main component, storage stability and coating film smoothness cannot be simultaneously satisfied. That is, in order to have good coating smoothness, it is necessary to select an epoxy resin having a low melt viscosity as much as possible, but in the case of bisphenol A type epoxy resin, the lower the melt viscosity, the smaller the epoxy equivalent, Alternatively, since the softening point is low, blocking is easily caused and there is a problem in storage stability. Therefore, it is necessary to maintain a low temperature during the operation, and there is still a problem in terms of handling such that the resin composition cannot be left at room temperature for a long time. On the other hand, in order to obtain good storage stability, a high molecular weight epoxy resin must be used, but in this case, there is a problem in terms of coating film smoothness.

[0008]

There is a need for a photocationically polymerizable epoxy resin-based solid composition which is excellent in storage stability, coating smoothness, and odor-free reactivity.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that a composition which simultaneously satisfies the above performance can be obtained. That is, the present invention provides the following equation (1):

[0010]

Embedded image

Wherein R ₁ and R _{2 each} represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a halogen atom, and a cationic photopolymerization initiator. (2) R ₁ and R ₄ are methyl groups.
A cationic photopolymerizable epoxy resin-based solid composition of (3)
The epoxy resin represented by the formula (1) is used in 5 of all epoxy resins.
(1) or (2)
The cationic photopolymerizable epoxy resin-based solid composition described,
(4) The cationic photopolymerization initiator is represented by the following general formula (2)

[0012]

Embedded image

(Wherein R ₃ and R ₄ are each a hydrogen atom,
Represents an alkyl group, a halogen atom, a hydroxyalkyloxy group or an alkoxy group; R ₅ and R ₆ each represent a hydrogen atom, a halogen atom or an alkyl group;
bF ₆ , PF ₆ , AsF ₆ , BF ₄ or B (C
It represents a ₆ F _{5) 4.} ) Or general formula (3)

[0014]

Embedded image

(Wherein R ₇ and R ₈ are each a hydrogen atom,
Represents an alkyl group, a halogen atom, a hydroxyalkyloxy group or an alkoxy group, R ₉ represents a hydrogen atom, a halogen atom or an alkyl group, and X represents SbF ₆ , P
Represents F ₆ , AsF ₆ , BF ₄ or B (C ₆ F ₅ ) ₄ . (1) to (3) above,
(5) an article having a cured coating of the composition according to any one of the above (1) to (4); and (6) an article having a cured coating of the composition according to any one of the above (1) to (4).
(7) The article according to (5) above, which is a printed wiring board.
A powder coating comprising a powder of the composition according to any one of (1) to (5).

BEST MODE FOR CARRYING OUT THE INVENTION

The epoxy resin used in the composition of the present invention is an epoxy resin comprising a 4,4'-biphenol derivative having the structural formula of the formula (1), wherein R ₁ , R ₂
Represents a hydrogen atom, a halogen atom such as Cl or Br, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an alkyl group having 1 to 6 carbon atoms such as a sec-butyl group or a tert-butyl group, Preferably, R ₁ , R
_An epoxy resin in which ₂ is a methyl group.

The epoxy resin represented by the above general formula (1) exhibits crystallinity, and has a characteristic that the viscosity at the time of melting is remarkably lower than that of the solid bisphenol A type epoxy resin. The composition has a low melt viscosity without impairing the properties, and a smooth coating film can be formed. The epoxy resin represented by the general formula (1) is usually 5 to 100% by weight, preferably 10 to 100% by weight, more preferably, of all epoxy resins in the composition.
20 to 100% by weight. When the amount is less than 5% by weight, the above-mentioned effect is small.

The epoxy resin represented by the general formula (1)
Other epoxy resins may be used in combination. As the epoxy resin used in combination, for example, bisphenol A,
Bisphenol F, bisphenol S, 2,2'-methylene-bis (4-methyl-6-tert-butylphenol), 2,2'-methylene-bis (4-ethyl-6
tert-butylphenol), 4,4′-butylylene-bis (3-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenol), trishydroxy Phenylmethane, pyrogallol, phenols having a diisopropylidene skeleton, phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenylfluorene, and polyfunctional epoxy glycidyl ethers of polyphenol compounds such as phenolized polybutadiene Resin, phenol, cresols, ethylphenols, butylphenols, octylphenols,
Glycidyl etherified products of various novolak resins such as novolak resins, phenol novolak resins having a xylylene skeleton, phenol novolak resins having a dicyclopentadiene skeleton, and phenol novolak resins having a fluorene skeleton using various phenols such as bisphenol A, bisphenol F and bisphenol S as raw materials , An alicyclic epoxy resin having an aliphatic skeleton such as cyclohexane, a heterocyclic epoxy resin having a heterocyclic ring such as an isocyanuric ring and a hydantoin ring, brominated bisphenol A, brominated bisphenol F, brominated bisphenol S, and brominated phenol Novolak, brominated cresol novolak,
Chlorinated bisphenol S, chlorinated bisphenol A
And glycidylated halogenated phenols.

The cationic photopolymerization initiator used in the present invention is not particularly limited. However, considering the reactivity, particularly the reactivity when a pigment is contained, the odor peculiar to the initiator, and the like, a sulfonium salt having a thioxanthone structure, Sulfonium salts having a benzophenone structure are preferred, and those which are solid at ordinary temperature are particularly preferred. Further, those which do not dissociate at about the level of ultraviolet light from a fluorescent lamp generally used for illumination and have excellent storage stability as an initiator are preferable. For example, sulfonium salts having a thioxanthone structure represented by the above general formula (2) And a sulfonium salt having a benzophenone structure represented by the above general formula (3). The sulfonium salt having a thioxanthone structure represented by the general formula (2) is described in JP-A-8-165290, and the sulfonium salt having a benzophenone structure represented by the general formula (3) is described in JP-A-7-82244. It can be manufactured according to the method described.

[0020] In the general formula _{(2), R 3, R} 4 are each a hydrogen atom, an alkyl group, a halogen atom, a hydroxyalkyl group or an alkoxy _{group, R} 5, R
₆ represents a hydrogen atom, a halogen atom or an alkyl group,
X is SbF ₆ , PF ₆ , AsF ₆ , BF ₄ , or B
(C ₆ F ₅ ) ₄ is represented. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group,
Examples thereof include an alkyl group having 1 to 5 carbon atoms such as a butyl group. Examples of the halogen atom include F, Cl, Br, and I. Examples of the alkoxy group include a group having 1 to 5 carbon atoms such as a methoxy group and an ethoxy group. Examples of the hydroxyalkyloxy group include a hydroxyalkyloxy group having 1 to 5 carbon atoms such as a hydroxymethyloxy group and a hydroxyethyloxy group. Next, specific examples of the compound of the formula (2) are shown in Table 1.

[0021]

Table 1 Table 1 Compound No. _{R 3 R 4 R 5 R 6} X 1 methyl methyl i- propyl H SbF ₆ 2 methyl methyl i- propyl H PF ₆ 3 methyl methyl Cl H PF ₆ 4 methoxy methoxy i- propyl Group HPF ₆

In the general formula (3), R ₇ and R ₈ each represent a hydrogen atom, an alkyl group, a halogen atom, a hydroxyalkyloxy group or an alkoxy group, and R ₉ represents a hydrogen atom, a halogen atom or an alkyl group; X is SbF ₆ ,
PF ₆ , AsF ₆ , BF ₄ , or B (C ₆ F ₅ ) ₄ . Examples of the alkyl group include an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and a butyl group. Examples of the halogen atom include F, Cl, Br, and I. Examples of the alkoxy group include an alkoxy group having 1 to 5 carbon atoms such as a methoxy group and an ethoxy group. Examples of the hydroxyalkyloxy group include a alkoxy group having 1 carbon atom such as a hydroxymethyloxy group and a hydroxyethyloxy group. To 5 hydroxyalkyloxy groups. Next, specific examples of the compound of the formula (3) are shown in Table 2.

[0023]

Table 2 Table 2 Compound No. R ₇ R ₈ R ₉ X 5 methyl methyl t- butyl group _{PF 6 6 F F H PF 6} 7 Br Br Cl SbF 6

These sulfonium salts are preferably used in an amount of 1 to 5 parts by weight based on 100 parts by weight of the epoxy resin. Further, it can be used in combination with other conventionally known photopolymerization initiators.

The composition of the present invention comprises a chain transfer agent, a sensitizer,
Coloring agents, anti-armpit agents, leveling agents, coupling agents,
Flame retardants, inorganic fillers and the like can be added. If necessary, a curing agent may be appropriately combined.

Examples of the chain transfer agent include carboxylic acids, aldehydes, phenols, alcohols and the like. Examples of the carboxylic acids include aliphatic polycarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, dimerized linolenic acid, and trimerized linolenic acid, tartaric acid, lactic acid, and aliphatic acids such as citric acid. Hydroxycarboxylic acid, tetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, hexahydrophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, 4-
Alicyclic polycarboxylic acids such as methylhexahydrophthalic acid, polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and aromatic polycarboxylic acids such as benzophenyltetracarboxylic acid. Can be

Examples of the aldehydes include malondialdehyde, succinyl aldehyde, glutaraldehyde, isophthaldialdehyde, terephthalaldehyde,
Examples thereof include aliphatic, alaliphatic, and aromatic aldehydes such as salicylaldehyde.

Examples of phenols include resorcinol, hydroquinone, bis (4-hydroxyphenyl) methane, 4,4-dihydroxybiphenylsulfone, 2,2-bis (4-hydroxyphenyl) propane, and 2,2-bis Examples include polyvalent, mononuclear, and polynuclear phenols such as (3,5-dibromo-4-hydroxyphenyl) propane.

As alcohols, for example, ethylene glycol
Recall, polyethylene glycol (2 to 100
Full polymerization degree), polyethylene oxide-polypropylene
Oxide-polyethylene oxide block copolymer
-, Neopentyl glycol, 2-ethyl-2'-pro
Pill-1,3-propanediol, hydroxypivalyl
Hydroxypivalate, 1,4-butanediol, 1,
6-hexanediol, 3 (4), 8 (9) -bis (H
Droxymethyl) -tricyclo [5.2.1.
0 ^2,6] Decane, 1,1,1-trihydroxymethyl
Propane, bis (2-hydroxyethylhydroquinone)
Ether, hydride with acid value less than 110 mg KOH / g
Hydroxyl-terminated polyester having a number of roxy groups, β
-Hydroxy ether, ε-caprolactan
Secondary hydroxyl groups or polyvalent
Such as the reaction product of alcohol and ε-caprolactone
At least one, and preferably two, aliphatic primary in the molecule
All compounds containing a hydroxy group are included. amount to use
The amount of the chain transfer agent is usually per equivalent of glycidyl group.
The functional group is 0 to 1 equivalent, preferably 0.05 to 0.1 equivalent.
8 equivalents. These chain transfer agents are reactive diluents, e.g.
For example, 4-butyrolactone, 1,2-propylene car
Bones or cyclic acetals such as dioxolane
It may be used by dissolving in water.

Examples of the sensitizer include anthracene, anthracene derivatives, perylene, and other polynuclear aromatic compounds.

Examples of the curing agent include trishydroxyphenylmethane, phenols having a diisopropylidene skeleton, phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenylfluorene, phenolized polybutadiene, 2'-methylene-bis (4-methyl-6-tert-butylphenol),
2,2'-methylene-bis (4-ethyl-6-tert
-Butylphenol), 4,4′-butylylene-bis (3-methyl-6-tert-butylphenol),
1,1,3-tris (2-methyl-4-hydroxy-5
-Tert-butylphenol), bisphenol A,
Bisphenols such as bisphenol F, bisphenol S, bisphenol C, bisphenol O (4,4'-dihydroxybiphenyl ether), and 4,4'-biphenylphenol are exemplified. These phenolic curing agents include alkyl groups having 1 to 12 carbon atoms such as methyl group, ethyl group, propyl group, butyl group, and octyl group, halogen groups such as fluorine, chlorine, and bromine, nitro groups, methoxy groups, ethoxy groups, and propoxy groups. May have one or two or more kinds of alkyl-substituted amino groups represented by alkoxy groups having 1 to 4 carbon atoms such as a butoxy group, an amino group and a dimethylamino group, and a diethylamino group. .

Further, as other curing agents, for example, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, ethylene glycol trimellitic anhydride, biphenyltetracarboxylic anhydride, Aromatic carboxylic anhydrides such as glycerol tris trimellitic anhydride, dodecenyl succinic anhydride, polyazeleic anhydride, polysebacic anhydride,
Aliphatic carboxylic acid anhydrides such as polydodecane dianhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, hetonic anhydride, hymic anhydride, 5 −
(2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride,
Examples include trialkyltetrahydrophthalic anhydride-maleic anhydride adducts and alicyclic carboxylic anhydrides such as chlorendic acid.

As the inorganic filler, for example, fused silica,
Crystalline silica, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, aluminum oxide, magnesium oxide, zirconium oxide, aluminum hydroxide, magnesium hydroxide, calcium silicate, Aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc., preferably fused silica, crystalline silica, calcium carbonate, aluminum oxide, zirconium oxide, aluminum hydroxide , Magnesium carbonate, mica, talc, calcium silicate, aluminum silicate, lithium aluminum silicate, more preferably calcium carbonate, fused silica, crystalline silica, aluminum oxide Beam, is a mica.

Examples of the coupling agent include a titanate coupling agent and a silane coupling agent. Examples of titanate-based coupling agents include isopropyl triisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tri (dioctyl phosphate) titanate, isopropyl tris (dioctyl pyrophosphate) titanate, and isopropyl tri (N-aminoethyl-aminoethyl). Monoalkoxyl type such as titanate, chelate type such as bis (dioctyl pyrophosphate) oxyacetate titanate, bis (dioctyl pyrophosphate) ethylene titanate, quaternized type, tetraoctyl bis (ditridecyl phosphite)
Titanate, tetra (2,2-diallyloxymethyl-
Coordinated types such as (1-butyl) bis (ditridecyl) phosphite titanate are exemplified.

As the silane coupling agent, for example, 3
-Glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4
A silane coupling agent having an epoxy group such as -epoxycyclohexyl) ethyltrimethoxysilane;
Examples include silane coupling agents having an amino group such as (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyltrimethoxysilane, and 3-aminopropyltriethoxysilane. Can be

As the flame retardant, inorganic flame retardants such as antimony trioxide, antimony pentoxide, tin oxide, tin hydroxide, molybdenum oxide, zinc borate, barium metaborate, red phosphorus, aluminum hydroxide, magnesium hydroxide, calcium aluminate, etc. Flame retardants, brominated flame retardants such as tetrabromophthalic anhydride, hexabromobenzene and decabromobiphenyl ether, and phosphoric flame retardants such as tris (tribromophenyl) phosphate. The coloring agent is not particularly limited, and various organic dyes such as phthalocyanine, azo, disazo, quinacridone, anthraquinone, flavanthrone, perinone, perylene, dioxazine, condensed azo, azomethine or methine, titanium oxide, lead sulfate, and oxidized Inorganic pigments such as zinc, chrome yellow, zinc yellow, chrome vermillion, red iron oxide, cobalt purple, navy blue, ultramarine, carbon black, chrome green, chromium oxide, and cobalt green. As a leveling agent, a molecular weight of acrylates such as ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate of 40
Oligomers of 00 to 12000, epoxidized soybean fatty acid, epoxidized abiethyl alcohol, hydrogenated castor oil,
Benzoin and the like.

In order to prepare the photocationically polymerizable epoxy resin-based solid composition of the present invention, an epoxy resin of the formula (1):
Photo-cationic polymerization initiator, other epoxy resin as required,
After dry-mixing other initiators, chain transfer agents, sensitizers, curing agents, inorganic fillers, coupling agents, flame retardants, coloring agents, leveling agents, and the like using a Henschel mixer, a kneader, After subjecting the mixture to a melt mixing treatment at 110 ° C. or lower using an extruder or the like, the mixture may be cooled and solidified, finely pulverized, and then classified. The particle size of the obtained powder composition is usually 10 to 180 µm, preferably 10 to 150 µm, more preferably 10 to 106 µm.

When the composition of the present invention is used as a powder coating, the thickness of the coating is usually 1 to 200 μm, preferably 2 to 200 μm.
The composition is applied on the substrate so as to have a thickness of 100 μm, more preferably about 2 to 50 μm. When the thickness of the coating film is larger than 200 μm, the irradiation energy does not reach the entire layer, and it takes a long time to cure or poor curing. Examples of the substrate include metal, wood, paper, rubber, plastic, glass, and ceramic products. As a method for applying the composition of the present invention, a method usually used for powder coating,
For example, it is applied by a tribo method, an electrostatic spray method, a fluid immersion method, an electrostatic fluid immersion method, a sprinkling method, a rolling method, a spray method, a thermal spray method, a fog box method, or the like. The coating film is formed in a heated air circulation furnace before being irradiated with energy rays, or after being heated and melted by radiant heat such as infrared rays, or is formed by heat from a UV lamp during irradiation with energy rays. Curing is performed by irradiating the molten coating film with energy rays. As an appropriate energy ray, it is preferable to use an energy ray having a wavelength of 200 to 500 nm obtained from a high-pressure mercury lamp, a low-pressure mercury lamp, a xenon lamp, a metal halide lamp, a germicidal lamp, a laser beam or the like. Exposure to an energy ray depends on the intensity of the energy ray, but usually about 0.1 to 10 seconds is sufficient. However, a relatively thick coating material or a compound containing many double bonds is blended. For systems such as high-fill systems, it is preferable to spend more time. In addition, although the resin is cured by polymerization 0.1 seconds to several minutes after the irradiation with the energy beam, it is preferable to heat at the time of the irradiation with the energy beam or after the irradiation with the energy beam in order to promote the polymerization reaction.

The article having a cured coating of the composition of the present invention is not particularly limited, and may be, for example, an insulating layer of a printed wiring board, a coil impregnation, a primer for an electronic component such as a film capacitor or a tantalum capacitor, an exterior material, and a motor. Iron core insulation, various printing inks, can paints, general paints, resist inks, adhesives, etc., and especially the melt viscosity of the printed wiring board, electronic components, motor iron core insulation, can paints, and the composition of the present invention Since it is extremely low and has excellent impregnating properties, it is suitable for fixed impregnation applications such as motor coils. It has been proposed to use a crystalline epoxy resin to fix and impregnate the motor coil etc., but if the molten resin drips during curing and if the gel time is shortened to avoid the problem, And there are disadvantages in that new problems such as stability over time and cost are derived. However, since the composition of the present invention cures instantly as described above, there is no problem of sagging during curing. In the resin impregnated in the back of the coil, the part that is not irradiated with energy rays is uncured, but in this case, if a heat curing accelerator is blended, only the surface is cured by photocationic polymerization, and then heat curing is performed, the quality will be improved. A cured product having no problem can be obtained.

The thickness of the cured film of the composition of the present invention is usually 1 to 200 μm, preferably 2 to 100 μm, more preferably about 2 to 50 μm.

[0041]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, “parts” means parts by weight.

Example 1 19.2 parts of YX-4000 (manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 185 g / eq, R ₁ and R ₂ in the formula (1) are methyl groups), YD-904 (manufactured by Toto Kasei, Bisphenol A type epoxy resin, epoxy equivalent 947g / e
q) 76.9 parts, Compound No. 2.9 parts of the cationic photopolymerization initiator, 0.5 part of a leveling agent (manufactured by Monsanto Chemical, Modaflow Powder), and benzoin (reagent) 0.1 part.
Five parts were pulverized and mixed by a mixer, and then melt-mixed using a biaxial kneader. The obtained kneaded product was cooled and solidified, then pulverized and passed through a 106 μm sieve to obtain an epoxy resin-based solid composition of the present invention. Then, using this composition, an iron plate surface-treated with zinc phosphate was applied to a thickness of about 20 μm with a tribogan (manufactured by Nordson), and then coated with a high-pressure mercury lamp (120 w / cm ² ) to a thickness of 3.5 cm. Ultraviolet rays of 520 mJ / cm ^{2 were} irradiated from a distance to be cured.

Example 2 19.2 parts of YX-4000 (manufactured by Yuka Shell Epoxy, epoxy equivalent: 185 g / eq), YD-904 (manufactured by Toto Kasei, bisphenol A type epoxy resin, epoxy equivalent: 947 g / eq) 9 parts, Compound No. 2.9 parts of the cationic photopolymerization initiator of No. 2, 0.5 parts of a leveling agent (manufactured by Monsanto Chemical, Modaflow Powder) and 0.5 parts of benzoin (reagent) were crushed and mixed with a mixer, and then mixed with a biaxial kneader. And melt mixed. The obtained kneaded product was cooled and solidified, then pulverized and passed through a 106 μm sieve to obtain an epoxy resin-based solid composition of the present invention. Next, using this composition, a tribogun (manufactured by Nordson Corporation) was used to coat an iron plate surface-treated with zinc phosphate to a thickness of about 20 μm, and then 3.5 cm with a high-pressure mercury lamp (120 w / cm ² ).
520 mJ / cm ^{2 was} irradiated from the distance of 520 to cure.

Example 3 19.2 parts of YX-4000 (manufactured by Yuka Shell Epoxy, epoxy equivalent: 185 g / eq), YD-904 (manufactured by Toto Kasei, bisphenol A type epoxy resin, epoxy equivalent: 947 g / eq) 9 parts, Compound No. 2.9 parts of the cationic photopolymerization initiator, 0.5 parts of a leveling agent (manufactured by Monsanto Chemical, Modaflow Powder) and 0.5 parts of benzoin (reagent) were pulverized and mixed with a mixer, and then mixed with a biaxial kneader. And melt mixed. The obtained kneaded product was cooled and solidified, then pulverized and passed through a 106 μm sieve to obtain an epoxy resin-based solid composition of the present invention. Next, using this composition, a tribogun (manufactured by Nordson Corporation) was used to coat an iron plate surface-treated with zinc phosphate to a thickness of about 20 μm, and then 3.5 cm with a high-pressure mercury lamp (120 w / cm ² ).
520 mJ / cm ^{2 was} irradiated from the distance of 520 to cure.

Example 4 19.1 parts of YX-4000 (manufactured by Yuka Shell Epoxy, epoxy equivalent: 185 g / eq), YD-904 (manufactured by Toto Kasei, bisphenol A type epoxy resin, epoxy equivalent: 947 g / eq) 6 parts, compound no. 2.9 parts of the cationic photopolymerization initiator, 0.5 parts of triphenylphosphine (reagent), 0.5 parts of a leveling agent (manufactured by Monsanto Chemical, Modaflow Powder), and 0.5 parts of benzoin (reagent) And then melt-mixed using a biaxial kneader. The obtained kneaded product was cooled and solidified, then pulverized and passed through a 106 μm sieve to obtain an epoxy resin-based solid composition of the present invention. Then, using this composition, an iron plate surface-treated with zinc phosphate was applied to a thickness of about 20 μm with a tribogan (manufactured by Nordson), and then coated with a high-pressure mercury lamp (120 w / cm ² ) to a thickness of 3.5 cm. Ultraviolet rays were irradiated at 1040 mJ / cm ² from a distance and cured.

The appearance of the coating film samples obtained in Examples 1 to 4 was observed. ◎ is glossy and excellent in smoothness,
○ indicates a slightly yuzu skin but shiny, and x indicates a yuzu skin with smoothness. In addition, the coating film sample was left on a hot plate at 120 ° C., scratched with a fine-tipped tool, and observed for tearing of the coating film. Regarding the storage stability, the obtained powder was allowed to stand at room temperature (25 ° C.) for one week, and the presence or absence of blocking was confirmed. The results are shown in Table 3. The evaluation criteria for the appearance are as follows. ◎: Smooth and glossy ○: Slight cracks are observed but glossy ×: Many wrinkles and no gloss

Table 3 Appearance Odor High-temperature storage stability Example 1 ◎ None No break good (no blocking) Example 2 ◎ None No break good (no blocking) 4 ◎ None No breakage Good (no blocking)

As is apparent from the results, the composition of the present invention has no odor, has good storage stability, cures in a short time by irradiation with ultraviolet light, has a smooth and glossy coating surface, and is left at high temperature. However, the coating film is hardly damaged and a coating film having good physical properties can be obtained.

[0049]

The photocationically polymerizable epoxy resin-based solid composition of the present invention has very excellent storage stability and excellent coating film smoothness. It is also excellent in workability, does not contain an organic solvent, and can be cured for a short time, so that it is useful from the viewpoint of economy, productivity, and environmental friendliness.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Akiki Niimoto 7-6-2-906 Suzuya, Yono-shi, Saitama

Claims (7)

[Claims] (1) Formula (1) (Wherein R ₁ and R ₂ represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a halogen atom), and a photocationic cation comprising a photocationic polymerization initiator. Polymerizable epoxy resin-based solid composition. 2. The photocationically polymerizable epoxy resin-based solid composition according to claim _1, wherein R ₁ and R ₂ are methyl groups. 3. The epoxy resin according to claim 1, wherein the epoxy resin represented by the formula (1) is contained in an amount of 5 to 100% by weight of the total epoxy resin.
The cationic photopolymerizable epoxy resin-based solid composition according to the above. 4. The cationic photopolymerization initiator is represented by the following general formula (2): (Wherein, R ₃ and R ₄ are each a hydrogen atom, an alkyl group,
R ₅ and R ₆ each represent a hydrogen atom, a halogen atom or an alkyl group, and X represents SbF ₆ or PF
₆ , AsF ₆ , BF ₄ or B (C ₆ F ₅ ) ₄ . ) Or general formula (3) (Wherein, R ₇ and R ₈ are each a hydrogen atom, an alkyl group,
R ₉ represents a hydrogen atom, a halogen atom or an alkyl group, X represents SbF ₆ , PF ₆ , AsF ₆ ,
Represents BF ₄ or B (C ₆ F ₅ ) ₄ . The photocationically polymerizable epoxy resin-based solid composition according to any one of claims 1 to 3, which is a compound represented by the formula: 5. An article having a cured coating of the composition according to claim 1. 6. The article according to claim 5, which is a printed wiring board. 7. A powder coating comprising a powder of the composition according to any one of claims 1 to 4.