JP2911958B2 - UV curable electrodeposition coating composition - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an electrodeposition coating composition for a printed wiring photoresist, and more particularly, to easily remove an unexposed portion of an electrodeposition coating film exposed through a negative or positive film. The present invention relates to an ultraviolet-curable electrodeposition coating composition for a printed wiring photoresist which can be removed by development and can form an excellent printed wiring circuit pattern.

[Prior art] Conventionally, in order to produce a printed wiring board, generally, a copper foil is laminated on a laminate board, and a photosensitive film is laminated thereon, and a photographic negative is further laminated and exposed and exposed. After development, unnecessary copper foils other than the circuit pattern are etched, and then the photosensitive film is removed, whereby a printed circuit is formed on the laminate, which is an insulator.

Since the photosensitive film used in the above method has a thickness as large as about 50 μm in general, the circuit pattern formed by exposure and development is not sharp, and the photosensitive film can be uniformly laminated on the copper foil surface. However, there is a problem that the photosensitive film is hardly removed in a developing process despite the fact that the photosensitive film is expensive.

[Problems to be Solved by the Invention] The present invention solves the above-mentioned problems by using a photosensitive film when producing a printed wiring board. It is intended to use a photocurable coating film, and fulfills this purpose, that is, a uniform coating film that can be developed on the surface of a copper-clad laminate, and a coating film excellent in photosensitivity. To provide an electrodeposition coating composition for a printed wiring photoresist capable of forming a coating. Although photocurable electrodeposition coatings have been partially put into practical use for printed wiring photoresists, development of photoresists with higher resolution is desired.

In the conventional photo-curing type electrodeposition photoresist, it is generally necessary to increase the exposure amount in order to obtain a high-resolution resist, so that there is a problem that the exposure time is long and the productivity is deteriorated.

[Means for Solving the Problems] The present inventors have conducted intensive studies to obtain an electrodeposition coating composition suitable for a printed wiring photoresist, which does not have the above-mentioned problems, and as a result, it has found that the polymerizable unsaturated polymer is unsaturated. The inventors have found that the problem can be solved by adding a certain specific nitrogen-containing compound to an ultraviolet-curable electrodeposition coating composition containing a resin and a water-insoluble photopolymerization initiator as main components, and have completed the present invention. .

Thus, according to the present invention, (a) an ultraviolet curable resin containing a photosensitive group and an ionic group capable of being crosslinked or polymerized by irradiation with ultraviolet light, (b) a water-insoluble photopolymerization initiator, and (c) General formulas (1) to (6) In the formula, X represents a hydrogen atom or a hydroxyl group, and R ₁ , R ₂ and
R ₃ represents a hydrogen atom, a chlorine atom or an alkyl group having 1 to 12 carbon atoms, In the formula, R ₄ and R ₅ are each a hydrogen atom or a carbon number of 1 to 12.
Represents an alkyl group of In the formula, R ₆ , R ₇ and R ₈ each represent a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 12 carbon atoms, In the formula, R ₉ , R ₁₀ and R ₁₁ are each a hydrogen atom, a hydroxyl group,
Represents an alkyl group having 1 to 12 carbon atoms or an alkoxyl group having 1 to 12 carbon atoms, In the formula, R ₁₂ represents a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 12 carbon atoms or an alkoxyl group having 1 to 12 carbon atoms, In the formula, R ₁₃ and R ₁₄ are each a hydrogen atom or carbon number 1 to
Represents an alkyl group of 12, wherein n is an integer of 1 to 3, an ultraviolet-curable electrodeposition coating composition having a wavelength of less than 250 to 400 nm, comprising at least one nitrogen-containing compound selected from Provided.

Hereinafter, the photocurable electrodeposition coating composition of the present invention will be described in more detail.

(A) UV-curable resin (hereinafter, simply referred to as photo-curable resin) The UV-curable resin (a) used in the present invention includes a photosensitive group capable of undergoing a crosslinking reaction or a polymerization reaction upon irradiation with light and an ionic resin. A polymer that is soluble in an aqueous alkali solution or an aqueous acid solution containing a group, that is, an anionic or cationic group, and undergoes a crosslinking reaction or a polymerization reaction by irradiation with ultraviolet light to substantially form an aqueous alkali solution or an aqueous acid solution. And an ultraviolet-curable polymer that is insoluble or hardly soluble.

The photosensitive group which may be present in the photocurable resin (a) is
A group capable of initiating crosslinking or polymerization by irradiation with ultraviolet light in the presence of the water-insoluble polymerization initiator (b). Specific examples of the photosensitive group having such characteristics include:
For example, a (meth) acryloyl group [CH ₂ CRCR—CO— (R represents a hydrogen atom or a methyl group)] cinnamoyl group, an allyl group and the like can be mentioned.

The photocurable resin (a) contains the above-mentioned anionic or cationic ionic group in addition to the photosensitive group. The amount of the ionic group and the photosensitive group can be varied over a wide range depending on the type and molecular weight of the base polymer, but generally, the anionic group (for example, a carboxyl group) is a photocurable group. The acid value of the resin is 20-300 (mgKOH / g
The amount of the cationic group (for example, tertiary amino group or onium base) is usually 0.2 to 5 mol / kg resin, preferably 0.3 to 0.3 mol / kg.
~ 2.0 mol / kg resin amount, and the photosensitive group is
Suitably it is included in an amount of 0.2 to 5.0 mol / kg resin, preferably 0.7 to 4.5 mol / kg resin.

Further, the photocurable resin (a) is generally 300 to 100,000, preferably 1,000 to 50,000, more preferably 3,000 to 30,000.
The glass transition temperature (Tg) is preferably 0 ° C. or more, particularly in the range of 5 to 70 ° C.

If the ionic group of the photocurable resin is less than the lower limit of the above range, the resin cannot be generally made water-soluble or water-dispersible, making it difficult to form an electrodeposition coating composition, and When the amount exceeds the above range, it becomes difficult to apply the electrodeposition paint to the substrate, and a large amount of electric power tends to be required to increase the amount of application.

Further, when the number-average molecular weight of the photocurable resin is less than 300, the coating film to be applied during electrodeposition coating is easily broken, and it tends to be difficult to obtain a uniform coating film.
When it exceeds 000, the electrodeposition coating film tends to have poor smoothness and a rough coated surface, and the image resolution tends to be poor.

Further, when the Tg of the photocurable resin is lower than 0 ° C., the electrodeposition coating film generally exhibits tackiness, and dust and the like tend to adhere to the coating film, making it difficult to handle.

Hereinafter, the anionic photocurable resin (a) used in the present invention will be specifically described.

(I) Photocurable resin containing (meth) acryloyl group as photosensitive group: The present photocurable resin can be produced, for example, by adding a glycidyl group-containing unsaturated compound to a high acid value acrylic resin. it can. The high acid value acrylic resin used at that time contains, for example, an α, β-ethylenically unsaturated acid such as acrylic acid or methacrylic acid as an essential component, and further contains (meth) acrylic acid esters such as methyl ( Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, hydroxyethyl (meth) acrylate, and styrene;
It is obtained by copolymerizing at least one unsaturated monomer selected from (meth) acrylonitrile, (meth) acrylamide and the like. Here, the α, β-ethylenically unsaturated acid generally has an acid value of an acrylic resin of 40 to 650,
Preferably, it can be used in such an amount as to be in the range of 60 to 500. Further, the number average molecular weight and glass transition temperature (Tg) of the high acid value acrylic resin are such that the photocurable resin obtained by adding a glycidyl group-containing unsaturated compound to the acrylic resin has the above-mentioned number average molecular weight and Tg. Is appropriately adjusted to have

On the other hand, as the glycidyl group-containing unsaturated compound to be added to the high acid value acrylic resin, specifically,
Glycidyl acrylate, glycidyl methacrylate and the like can be mentioned.

The addition reaction between the high acid value acrylic resin and the glycidyl group-containing unsaturated compound is performed according to a method known per se,
For example, it can be easily carried out by reacting at 80 to 120 ° C. for 1 to 5 hours using a catalyst such as tetraethylammonium bromide.

Further, the photocurable resin, a reaction product of a hydroxyl group-containing polymerizable unsaturated compound and a diisocyanate compound,
It can also be produced by adding to a high acid value acrylic resin having a hydroxyl group described in the section (ii).

Examples of the hydroxyl group-containing polymerizable unsaturated compound include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, N-methylolacrylamide, and the like. Examples of the diisocyanate compound include tolylene diisocyanate, Xylylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate and the like.

(Ii) Photocurable resin containing a cinnamoyl group as a photosensitive group: The photocurable resin is, for example, a high acid value acrylic resin containing a hydroxyl group and a substituted or unsubstituted cinnamic acid halide. , In the presence of a base, for example, in a pyridine solvent.
The hydroxyl group-containing high acid value acrylic resin used at that time contains, as essential components, the α, β-ethylenically unsaturated acid and the hydroxyl group-containing polymerizable unsaturated compound described in the above section (i), It can be obtained by copolymerizing with at least one other unsaturated monomer.

In the production of such a hydroxyl group-containing high acid value acrylic resin, α, β-ethylenically unsaturated acid is generally
The resulting photocurable resin has an acid value of 20 to 300, preferably 30.
Can be used in amounts that fall within the range of ~ 100,
Further, the hydroxyl group-containing polymerizable unsaturated compound is generally used in an amount of 5 to 97 parts by weight, preferably 20 to 75 parts by weight per 100 parts by weight of the high acid value acrylic resin. Can be.

On the other hand, the substituted or unsubstituted cinnamic acid halide is generally the above hydroxyl group-containing high acid value acrylic resin 100.
It can be used in an amount such that it is in the range of 6 to 180 parts by weight, preferably 30 to 140 parts by weight per part by weight.

Examples of the substituted or unsubstituted cinnamate halide that can be used include a nitro group, a cinnamate halide which may have 1 to 3 substituents selected from a lower alkoxyl group and the like on a benzene ring, More specifically, cinnamic acid chloride, p-nitrocinnamic acid chloride, p-methoxycinnamic acid chloride, p-ethoxycinnamic acid chloride and the like can be mentioned.

The reaction between these substituted or unsubstituted cinnamic acid halides and the hydroxyl group-containing acrylic resin is, for example, adding 20 to 100 parts by weight of pyridine to 100 parts by weight of the acrylic resin solution, and adding 20 to 100 parts by weight of dimethylformamide. The dissolved cinnamic acid chloride is added dropwise at 10 ° C or less, and then 30 ~
It is obtained by stirring at 70 ° C. for 3 to 8 hours. The purified product can be obtained by pouring the reaction solution into a large excess of methanol to precipitate the polymer, reprecipitating with a mixture of tetrahydrofuran and water, and further reprecipitating with a mixture of tetrahydrofuran and methanol.

(Iii) Photo-curable resin containing an allyl group as a photosensitive group: The photo-curable resin is, for example, allyl glycidyl ether in addition to the high acid value acrylic resin used in the above item (i). Or by adding a reactant of (meth) allyl alcohol and a diisocyanate compound to a hydroxyl group-containing high acid value acrylic resin.

The above addition reaction between the high acid value acrylic resin and the allyl glycidyl ether can be carried out in the same manner as in the method described in the above (i).

Moreover, in the photosensitive electrodeposition coating composition of the present invention, a cationic electrodeposition coating composition can be obtained by using a conventionally known cationic resin in addition to the anionic resin as the photocurable resin (a). It is.

Examples of such a cationic resin include a resin obtained by adding a reactant of a hydroxyl group-containing polymerizable unsaturated compound and a diisocyanate compound to an acrylic resin having a hydroxyl group and a tertiary amino group; Tertiary amino group-containing resin obtained by reacting the remaining epoxy group with a polymerizable unsaturated monocarboxylic acid or a hydroxy group-containing unsaturated compound after reacting with a tertiary amine; glycidyl group-containing unsaturated compound and tertiary amino A tertiary amino group-containing compound obtained by reacting a polymerizable unsaturated monocarboxylic acid or a hydroxyl group-containing polymerizable unsaturated compound with a resin obtained by copolymerizing a group-containing unsaturated compound with another polymerizable unsaturated monomer. Resin: reacting an epoxy resin with a polymerizable unsaturated monocarboxylic acid or a hydroxyl-containing unsaturated compound, Onium base-containing resins obtained by onium salification in the presence of a tertiary amino compound, thioether, phosphine or the like with a carboxylic acid. These resins may be used alone or in combination of two or more. Can be.

(B) Water-insoluble polymerization initiator The composition for an ultraviolet-curable electrodeposition coating composition of the present invention contains a water-insoluble polymerization initiator. The initiator is decomposed by irradiating ultraviolet rays, and initiates a crosslinking reaction or a polymerization reaction of the photosensitive group of the photocurable resin.

As such a polymerization initiator, a compound which generates a group active for a crosslinking reaction or a polymerization reaction of the photosensitive group by a cleavage reaction of itself by photoexcitation or a hydrogen abstraction reaction from another molecule, Particularly, in the present invention, those substantially insoluble in water (for example, those having a solubility in water of 2 g / 100 ml or less water) are used. By using such a water-insoluble polymerization initiator, it can be efficiently precipitated during electrodeposition coating and contained in the coating film to form a coating film with high sensitivity.

Specific examples of such a polymerization initiator include the following.

Benzophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzyl, diphenyl disulfide, tetramethylthiuram monosulfide, diacetyl, eosin, thionin, Michler's ketone, anthraquinone, chloranthraquinone, methylanthraquinone, α-hydroxyisobutylphenone, p
-Isopropyl α-hydroxyisobutylphenone, α
α'dichloro-4-phenoxyacetophenone, 1-hydroxyl-cyclohexylacetophenone, 2.2 dimethoxy-2-phenylacetophenone, methylbenzoylformate, 2-methyl-1- [4- (methylthio) phenyl] · 2 Morpholino propene, thioxanthone, etc.

The amount of these polymerization initiators is not critical, and can be varied in a wide range depending on the type and the like. In general, the solid content of the photocurable resin (a)
It can be in the range of 0.1 to 2.5 parts by weight, preferably 0.2 to 10 parts by weight per part by weight. If the amount is less than 0.1 part by weight, the curability tends to decrease, and if the amount exceeds 25 parts by weight, the stability of the obtained composition tends to decrease. These polymerization initiators may be used alone or as a mixture of two or more.

(C) Nitrogen-containing compound When the nitrogen-containing compounds represented by the above general formulas (1) to (6) are blended in the composition for an ultraviolet-curable electrodeposition coating composition of the present invention, the sensitizing effect is improved and the sensitivity is extremely high. Will be high. Similarly, the resolving power of the image obtained by using this is improved.

Although the reason for the above effect is not clear, since these nitrogen-containing compounds (c) have a strong ability to form a chelate with metal ions such as copper, the metal ions eluted during electrodeposition coating and the photocurable resin (a) In order to suppress the reaction with an ionic group such as a carboxyl group in the resin, the polymerized resin is prevented from becoming high molecular weight or crosslinked by metal ions. It is considered that the difference between the solubility of the unexposed portion and that of the unexposed portion becomes large, and as a result, the resolving power is improved.

In such a nitrogen-containing compound (c), general formula (1)
As shown in, for example, And benzotriazoles.

As the compound represented by the general formula (2), for example, And virazoles.

Examples of the compound represented by the general formula (3) include: And the like.

Examples of the compound represented by the general formula (4) include: And the like.

Examples of the compound represented by the general formula (5) include: And the like.

In addition, as the one represented by the general formula (6), for example, Can be mentioned.

Among the above-mentioned nitrogen-containing compounds (c), those particularly preferred in the present invention are benzotriazoles represented by the aforementioned general formula (1).

The nitrogen-containing compound (c) can be used alone or in combination of two or more in the composition for electrodeposition coating of the present invention, and when used, the amount of the photocurable resin (a) Generally 0.01 to 20 parts by weight based on 100 parts by weight of solids,
Preferably it is in the range of 0.1 to 10 parts by weight.

(D) Other Components The composition for electrodeposition coating composition of the present invention may further comprise a polymerizable unsaturated group-containing resin such as an ethylenically unsaturated group, if necessary, in addition to the photocurable resin (a). Polyester acrylate resin, polyurethane resin, epoxy resin, acrylic resin, etc. containing vinyl; vinyl monomer such as (meth)
Acrylic esters; oligomers, for example, diethylene glycol di (meth) acrylate and the like are usually blended in a range of 100 parts by weight or less, preferably 50 parts by weight or less per 100 parts by weight of the solid content of the photocurable resin (a). It is also possible to appropriately adjust the performance of the formed coating film.

Adjustment of the composition for the ultraviolet-curable electrodeposition coating composition for the ultraviolet-curable electrodeposition coating composition of the present invention, for example,
It can be prepared by mixing a polymerization initiator (b), a nitrogen-containing compound (c) and other components (d) with a water-dispersed or water-soluble product of the photocurable resin (a).

Water-dispersion or water-solubilization of the photocurable resin (a) is performed by neutralizing the resin (a) with an alkali (neutralizing agent) when an anionic group such as a carboxyl group is introduced into the resin (a). When a cationic group such as an amino group is introduced, the reaction is carried out by neutralization with an acid (neutralizing agent). Examples of the alkali neutralizing agent used at that time include alkanolamines such as monoethanolamine, diethanolamine and triethanolamine; alkylamines such as triethylamine, diethylamine, monoethylamine, diisopropylamine, trimethylamine and diisobutylamine; dimethyl Alkylalkanolamines such as aminoethanol; alicyclic amines such as cyclohexylamine; alkali metal hydroxides such as sodium hydroxide and sodium hydroxide; and ammonia. Examples of the acid neutralizer include monocarboxylic acids such as formic acid, acetic acid, lactic acid, and butyric acid. These neutralizing agents can be used alone or in combination. The amount of the neutralizing agent to be used is generally in the range of 0.2 to 1.0 equivalent, preferably 0.3 to 0.8 equivalent per 1 mol of the ionic group contained in the resin (a).

In order to further improve the fluidity of the water-soluble or water-dispersed resin component, a hydrophilic solvent such as methanol, ethanol,
Isopropanol, n-butanol, t-butanol,
Methoxyethanol, ethoxyethanol, butoxyethanol, diethylene glycol methyl ether, dioxane, tetrahydrofuran and the like can be added. The amount of the hydrophilic solvent used can be generally up to 300 parts by weight, preferably up to 100 parts by weight, per 100 parts by weight of the solid component of the resin (a).

Further, in order to increase the amount of the coater on the object to be coated, a hydrophobic solvent such as toluene,
Petroleum solvents such as xylene; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and butyl acetate; alcohols such as 2-ethylhexyl alcohol and benzyl alcohol can also be added. The compounding amount of these hydrophobic solvents can be generally up to 200 parts by weight, preferably 100 parts by weight or less per 100 parts by weight of the solid component of the resin (a).

In addition to the above objects, the above-mentioned solvent can be used as a solvent for dissolving the polymerization initiator (b) and the nitrogen-containing compound (c). When the polymerization initiator (b) and the nitrogen-containing compound (c) are hardly dissolved in the neutralized resin solution, these are dissolved in a suitable hydrophilic solvent or hydrophobic solvent in advance, and then the resin (a) is dissolved. It is desirable to mix. The solvent that can be used can be selected from those described above, and the amount used is sufficient to dissolve the polymerization initiator (b) and the nitrogen-containing compound (c).

Preparation of the composition for electrodeposition paint can be performed by a conventionally known method, and the resin (a), the polymerization initiator (b), the nitrogen-containing compound (c), and the like, which are made water-soluble by the above-mentioned neutralization, are used. Can be carried out by thoroughly mixing the component (d) and adding water.

The composition thus prepared is diluted with water in the usual manner, for example, with a pH in the range of 4 to 9, a bath concentration (solids concentration) of 3 to 25% by weight, preferably 5 to 15% by weight. The electrodeposition paint (or the coating bath) within the range described above can be used.

Electrodeposition coating and image formation The electrodeposition coating prepared as described above can be applied to the surface of a conductor to be coated as follows. As the conductor, a conductive material such as metal, carbon, and tin oxide, or a material obtained by fixing these materials to the surface of plastic or glass by lamination, plating, or the like can be used.

The bath temperature is controlled between 15 and 40 ° C., preferably between 15 and 30 ° C., and the pH and bath concentration are controlled within the stated ranges. Then, the conductor to be coated is immersed in an electrodeposition coating bath controlled in this way as an anode when the electrodeposition coating is an anion type or as a cathode when the electrodeposition coating is a cation type, and a DC voltage of 5 to 200 V is applied. Apply current. The energization time is suitably from 30 seconds to 5 minutes, and the obtained film thickness is generally 0.5 to 50 μm, preferably 1 to 10 μm in terms of dry film thickness.

After the electrodeposition coating, the object to be coated is taken out of the electrodeposition bath and washed with water, and then moisture and the like contained in the electrodeposition coating film are dried and removed with hot air or the like.

At this time, if necessary, a cover coat layer may be provided on the electrodeposition coating film by a method known per se (see JP-A-63-60594).

The actinic ray used for exposure in the present invention varies depending on the absorption wavelength of the photopolymerization initiation percent, but usually, ultraviolet rays having a wavelength in the range of 250 to 400 nm are suitable. Examples of light sources containing light of these wavelengths include sunlight, mercury lamps, xenon lamps, arc lamps, and various lasers having oscillation lines in the ultraviolet region. Curing of the coating film by irradiation with actinic rays is performed within a few minutes, usually in the range of 1 second to 20 minutes.

In the development process, the non-exposed part film on the coating film surface is washed away with an alkaline aqueous solution when the electrodeposition paint is anionic, or with an acid aqueous solution having a pH of 5 or less when the electrodeposition paint is cationic. This is done by: Alkaline aqueous solution is usually
Use is made of, for example, caustic soda, sodium carbonate, caustic potash, ammonia water, etc., which can impart water solubility by neutralizing with free carboxylic acids present in the coating film. Acetic acid, formic acid, or the like can be used as the acid aqueous solution.

After the development, the coating film is washed with water and dried with hot air or the like, so that a desired image is formed on the conductor. In addition, after the exposed conductor is removed by etching as necessary, the resist film is removed, and the printed circuit board can be manufactured.

The composition for electrodeposition coating composition of the present invention and an image forming method using the same can be used for a wide range of applications, such as a photoresist, a lithographic or letterpress plate-making material, a PS plate for offset printing, an information recording material, and a relief image forming material. Application is possible.

[Effect of the Invention] A uniform and smooth ultraviolet-sensitive light-sensitive coating film having an arbitrary thickness can be obtained by electrodeposition coating using the composition for electrodeposition coating material of the present invention. Since no advanced technique is required for forming the coating film, workability is greatly improved as compared with the conventional coating film forming method. In addition, thin films that could not be achieved with liquid paints or photosensitive films can be easily obtained simply by setting the electrodeposition conditions, and the image obtained by exposure is much clearer than conventional ones. . Furthermore, the composition for an electrodeposition coating composition of the present invention uses less organic solvent than conventional liquid coating compositions, and therefore is less harmful to humans and danger of fire.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. All parts and percentages are based on weight.

Example 1 Methyl methacrylate 40 parts, butyl acrylate 40
Part of a mixed solution consisting of 20 parts of acrylic acid and 2 parts of azobisisobutyronitrile at 110 ° C. in a nitrogen gas atmosphere.
Was added dropwise over 90 hours to 90 parts of propylene glycol monomethyl ether (hydrophilic solvent) held in the flask. After the dropping, the mixture is aged for 1 hour, a mixed solution composed of 1 part of azobisdimethyl valeronitrile and 10 parts of propylene glycol monomethyl ether is added dropwise for 1 hour, and the mixture is aged for 5 hours to obtain a high acid value acrylic resin (acid value of 155). ) A solution was obtained.
Next, 24 parts of glycidyl methacrylate, 0.12 part of hydroquinone and 0.6 part of tetraethylammonium bromide are added to this solution, and the mixture is reacted at 110 ° C. for 5 hours while blowing air into the polymerizable unsaturated resin (acid value about 50, photosensitive group). about
A 1.35 mol / kg resin, number average molecular weight 20,000) solution was obtained. After neutralizing 0.6 equivalent of this polymerizable unsaturated resin with triethylamine, 3 parts of 1H-benzotriazole and 6 parts of α-hydroxyisobutylphenone as a photopolymerization initiator are added, and the solid content ratio becomes 10%. Was added to obtain an electrodeposition coating bath (pH 7.0).

Example 2 10 parts of trimethylolpropane triacrylate was added to 225 parts of the polymerizable unsaturated resin solution of Example 1, neutralized with 0.6 equivalent of triethylamine, and then 4 parts of 1H-benzotriazole and α-photoinitiator as a photopolymerization initiator were added. After adding 7 parts of hydroxyisobutylphenone, water was added so that the solid content ratio became 10%, to obtain an electrodeposition coating bath.

Example 3 40 parts of methyl methacrylate, 25 of butyl acrylate
Part, 2-hydroxyethyl methacrylate 15 parts, acrylic acid 20 parts and azobisisobutyronitrile 2 parts in a mixed system of dioxane (hydrophilic solvent) 100 parts maintained at 105 ° C. under a nitrogen gas atmosphere. It was added dropwise over 2 hours and aged at the same temperature for 1 hour to obtain a high acid value acrylic resin (acid value 155) solution. Next, this solution 200
To 20 parts of an equimolar addition product of 2-hydroxyethyl methacrylate and tolylene diisocyanate, and reacted at 80 ° C. for 5 hours in a nitrogen gas atmosphere.
A solution of a polymerizable unsaturated resin (acid value: about 120, photosensitive group: about 0.56 mol / kg resin, number average molecular weight: about 20,000) usable in the present invention was obtained. After neutralizing 0.6 equivalent of this polymerizable unsaturated resin with dimethylaminoethanol, the compound (3,5-dimethylpyrazole), 5 parts of benzoin ethyl ether as a photopolymerization initiator were added, and then water was added so that the solid content ratio became 10%.
7.2)

Example 4 25 parts of methyl methacrylate, n-butyl acrylate
A mixture of 15 parts, 15 parts of acrylic acid, 45 parts of 2-hydroxyethyl methacrylate and 2 parts of azobisisobutyronitrile was kept at 80 ° C. under a nitrogen gas atmosphere.
It was removed in 100 parts of DMF in 3 hours. After dropping, the mixture was aged for 1 hour, 1 part of azobisdimethyl valeronitrile and DM
A mixed solution composed of 5 parts of F (dimethylformamide) was added dropwise over 1 hour, and the mixture was aged for 5 hours to obtain a high acid value acrylic resin (acid value 115) solution.

To 200 parts of this polymerization solution was added 120 parts of pyridine, and DMF150
Then, 57 parts of the cinnamic acid chloride dissolved in the mixture was added dropwise at 10 ° C. or lower, followed by stirring at 50 ° C. for 4 hours. The reaction solution was poured into methanol to precipitate a polymer, reprecipitated with THF (tetrahydrofuran) -water, further reprecipitated with THF-methanol, purified, and dried at room temperature under reduced pressure. The resulting photocurable resin having a cinnamoyl group as a photosensitive group had an acid value of 81, a Tg point of 51 ° C, and a number average molecular weight of about 20,000.

100 parts of this resin is propylene glycol methyl ether 5
0 parts, a solution dissolved in a mixed solvent of 50 parts of n-butanol was neutralized by 0.6 equivalents with triethylamine. After adding 5 parts of (1-hydroxybenzotriazole) and 5 parts of Michler's ketone as a photosensitizer, water was added so that the fixed share was 10%, and an electrodeposition coating bath (pH 6.9) was added.
And

Comparative Example 1 An electrodeposition coating bath was prepared in the same manner as in Example 1 except that 1H-benzotriazole used in Example 1 was omitted.

Comparative Example 2 An electrodeposition coating bath was prepared in the same manner as in Example 2 except that 1H-benzotriazole used in Example 2 was omitted.

Comparative Example 3 An electrodeposition coating bath was prepared in the same manner as in Example 3 except that 3,5-dimethylpyrazole used in Example 3 was omitted.

Comparative Example 4 An electrodeposition coating bath was prepared in the same manner as in Example 4 except that 1-hydroxybenzotriazole used in Example 4 was omitted.

Using the electrodeposition coating baths obtained in Examples 1-4 and Comparative Examples 1-4, a copper-clad laminate having a through-hole of 250 mm x 300 mm, thickness of 1.6 mm and diameter of 0.30 mm was used under the following conditions. Color coating was performed.

Bath temperature: 25 ° C Current density: DC current of 60mA / dm ² Distance between electrodes: 10cm Pole ratio: Electrode / painted plate = 1/2 Energizing time: 3 minutes After electrodeposition coating, dry at 80 ° C for 10 minutes and film thickness A coating of 15 μm was obtained.

Next, the electrodeposited plates prepared using the electrodeposition coating baths of Examples 1 to 4 and Comparative Examples 1 to 4 were
Both sides were irradiated with light through a 200 μm-thick negative film on which a pattern of line / space = 100 μm / 100 μm was drawn by using a vacuum printer device that performs one round trip of a lamp.

After the irradiation, the unexposed portion was completely washed out with 1% sodium carbonate solution and developed. After the development, copper was etched with ferric chloride, and the exposed portion of the coating film was removed with a 5% sodium hydroxide solution to obtain a printed circuit board.

About the printed circuit board obtained using each paint, 0.
Table 1 below shows the minimum irradiation dose for forming a resist film in the 30-mm through-hole and the copper remaining completely after etching, and the results of testing the state of the surface pattern at that time.

Measurement of irradiation amount An ultraviolet light meter UV-350 manufactured by Oak Manufacturing Co., Ltd. was placed on a glass plate of a vacuum printer and measured.

Observation of pattern state Observation was performed with a microscope with a magnification of 100 times with a scale.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification code FI H05K 3/06 H05K 3/06 M (58) Investigated field (Int.Cl. ⁶ , DB name) C09D 5/44

Claims (1)

(57) [Claims] 1. An ultraviolet curable resin containing a photosensitive group and an ionic group which can be cross-linked or polymerized by irradiation with ultraviolet light, (b) a water-insoluble photopolymerization initiator, and (c) a general formula (1) 1)-(6) In the formula, X represents a hydrogen atom or a hydroxyl group, and R ₁ , R ₂ and R ₃ each represent a hydrogen atom, a chlorine atom or an alkyl group having 1 to 12 carbon atoms. In the formula, R ₄ and R ₅ each represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, In the formula, R ₆ , R ₇ and R ₈ each represent a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 12 carbon atoms, In the formula, R ₉ , R ₁₀ and R ₁₁ each represent a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 12 carbon atoms or an alkoxyl group having 1 to 12 carbon atoms, In the formula, R ₁₂ represents a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 12 carbon atoms or an alkoxyl group having 1 to 12 carbon atoms, In the formula, R ₁₃ and R 14 are each a hydrogen atom or a carbon number of 1 to 12.
An ultraviolet-curable electrodeposition coating composition having a wavelength of less than 250 to 400 nm, comprising at least one nitrogen-containing compound selected from the group consisting of: