JPH0769612B2 - Electrodeposition coating method for printed wiring photoresist - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrodeposition coating method for printed wiring photoresists, and more particularly to a smooth coating film having no surface tackiness by electrodeposition coating on a copper clad laminate. The present invention relates to a two-coat electrodeposition coating method for a printed wiring photoresist capable of forming a coating film and forming a coating film which is easily cured by an actinic ray such as ultraviolet ray through a negative or positive film.

[Prior Art] To form a uniform film that is developable and excellent in UV curability on the surface of a copper clad laminate by using a photocurable film that has been conventionally obtained by electrodeposition coating. A printed wiring photoresist that can be used is obtained. However, in the case of this photoresist, since it can be obtained by 1-coat electrodeposition coating, the glass transition temperature of the resin constituting the photoresist is set so as to prevent the coating film and the negative or positive film from being caught in contact during exposure. It needs to be high.

[Problems to be Solved by the Invention] As described above, when the photocurable coating film is formed by the one-coat electrodeposition coating method, the glass transition temperature of the resin used is increased, while the film resistance during electrodeposition is increased. However, there is a problem in that the coating film cannot be thickened, and chain transfer does not easily occur during exposure, and the curability of the coating film due to ultraviolet rays deteriorates. In addition, when contact exposure is performed, a photoresist is formed by electrodeposition coating using a resin having a low glass transition temperature such that the coating film and the film stick to each other, and then a polyvinyl alcohol aqueous solution or a water-soluble acrylic resin aqueous solution is applied on it. There is a method of covering the surface with a non-adhesive coating film (cover coat). However, even in this method, when a copper clad laminate with through holes is used, the coating film inside the through holes does not cure due to the accumulation of ultraviolet rays in the through holes and the deterioration of the ultraviolet light transmission. However, there is a problem that the water is accumulated and poor drying occurs. In reality, the advent of technical means for solving these problems is desired.

[Means for Solving Problems] The inventors of the present invention have conducted extensive studies to find a technical means for solving the above problems, and as a result, have found a new electrodeposition coating method for solving the above problems. The present invention has been completed.

Thus, according to the present invention, after the photocurable anionic electrodeposition coating composition (A) is electrodeposited on a copper clad laminate, the coating film is further water-soluble at a glass transition temperature of 20 ° C. or higher. Alternatively, there is provided an electrodeposition coating method for a printed wiring photoresist, which comprises subjecting an anion electrodeposition coating composition (B) containing a water-dispersible resin as a main component to electrodeposition coating.

The photocurable anionic electrodeposition coating composition (A) in the method of the present invention basically comprises a water-soluble or water-dispersible polymerizable unsaturated resin and a photopolymerization initiator as main components. The composition of The polymerizable unsaturated resin used in the composition is not particularly limited as long as it is a water-soluble or water-dispersible resin containing an anionic group, and typical examples thereof will be described in the following (1) to ( 5) can be mentioned.

(1) A reaction product of a compound having a polymerizable unsaturated bond and a hydroxyl group in one molecule with a diisocyanate compound,
A polymerizable unsaturated resin obtained by adding to a high acid value acrylic resin having a hydroxyl group in the resin skeleton, or a combination of these with an ethylenically unsaturated compound having one or more polymerizable unsaturated bonds in one molecule Resin composition containing as a main component: Examples of compounds having a polymerizable unsaturated bond and a hydroxyl group in one molecule include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and N-methylol acrylamide. , Allyl alcohol, methallyl alcohol, etc. are included, and examples of diisocyanate compounds include tolylene diisocyanate, xylene diisocyanate,
Examples include hexamethylene diisocyanate and lysine diisocyanate.

The introduction of a hydroxyl group into a high acid value acrylic resin is imparted by using a compound having a polymerizable unsaturated bond and a hydroxyl group in the above-mentioned molecule as a copolymerization component, and the acid value is the same as that of acrylic acid, methacrylic acid or the like. It is provided by copolymerizing a saturated acid during the production of the acrylic resin.
The urethane-forming reaction between a compound having a polymerizable unsaturated bond and a hydroxyl group in one molecule and a diisocyanate compound and the urethane-forming addition reaction between these reactants and a high acid value acrylic resin having a hydroxyl group in the skeleton are carried out by a conventional method. Can be done at.

(2) Polymerizable unsaturated bond obtained by adding α / β-ethylenically unsaturated dibasic acid or its anhydride to the unsaturated bond in the fatty acid chain in the esterified product of epoxy resin having epoxy group and unsaturated fatty acid Resin composition containing a mixture of a resin and an ethylenically unsaturated compound having one or more polymerizable unsaturated bonds in one molecule as a main component: Examples of the unsaturated fatty acid include oleic acid, linoleic acid, linolenic acid and eleo Examples thereof include stearic acid, licanoic acid, ricinoleic acid, and arachidonic acid. Examples of the α / β-ethylenically unsaturated dibasic acid or its anhydride include maleic acid, maleic anhydride, fumaric acid, and itaconic acid. . In this resin component, oxidation is α ・ β
-The amount of ethylenically unsaturated dibasic acid or its anhydride can be adjusted, and the unsaturated equivalent can be adjusted depending on the type of unsaturated fatty acid and its amount used.

(3) A resin composition containing a mixture of a polymerizable unsaturated resin composed of an unsaturated fatty acid-modified high acid value alkyd resin and an ethylenically unsaturated compound having at least one polymerizable unsaturated bond in one molecule as a main component. This polymerizable unsaturated resin is a mixture of a dibasic acid having two carboxyl groups in one molecule and a polybasic acid having three or more carboxyl groups in one molecule, and two or more in one molecule. The unsaturated fatty acid is esterified with the hydroxyl group contained in the skeleton of the esterified product with the polyhydric alcohol having the hydroxyl group. In this case, the number of moles of acid component / the number of moles of alcohol component = 0.8 to 1.0 is preferable.

In this reaction, the acid value can be adjusted by the kind and amount of polybasic acid, and the unsaturated equivalent can be adjusted by the addition amount of unsaturated fatty acid. An acid value may be imparted by half-esterifying a dibasic acid to an unsaturated fatty acid-modified alkyd resin having hydroxyl groups in excess of carboxyl groups. Examples of the dibasic acid in this system include phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, maleic anhydride, fumaric acid, succinic acid, sebacic acid and the like, and examples of the polybasic acid include trimellitic acid,
Pyromellitic acid, pyromellitic anhydride, etc. are mentioned, and as the polyhydric alcohol, for example, ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, diglycerol, etc. are applied. it can. Further, as the unsaturated fatty acid, the same unsaturated fatty acid as that used when the epoxy resin in the polymerizable unsaturated resin of the above (2) is reacted can be exemplified.

(4) Resin composition containing a mixture of a polymerizable unsaturated resin composed of maleated oil and an ethylenically unsaturated compound having at least one polymerizable unsaturated bond in one molecule as a main component: Included are reactions obtained by reacting oils with conjugated or non-conjugated double bonds with maleic anhydride. Further, when styrene, vinyltoluene, cyclopentadiene, acrylic acid ester, methacrylic acid ester, etc. are added to this reaction product, the curability of the coating film is further improved. In these maleated oils, the acid value can be adjusted by the addition amount of maleic anhydride, and the unsaturated equivalent can be adjusted by the unsaturated bond contained in the oil. In this case, examples of the oil include linseed oil, tung oil, soybean oil, castor oil, coconut oil, sardine oil, cottonseed oil, hemp oil and the like.

(5) A polymerizable unsaturated resin obtained by adding a compound having a polymerizable unsaturated bond and a glycidyl group in the molecule to a high acid value acrylic resin, or one polymerizable unsaturated bond in one molecule with these. A resin composition containing a combination of the above ethylenically unsaturated compounds as a main component: This polymerizable unsaturated resin contains, for example, an unsaturated acid such as acrylic acid or methacrylic acid and another acrylic monomer. Resins obtained by adding a compound having a polymerizable unsaturated bond and a glycidyl group in one molecule such as glycidyl acrylate and glycidyl methacrylate to a high acid value acrylic resin obtained by polymerization are included.

The polymerizable unsaturated resin represented by the above (1) to (5) has an acid value of 20 to 300 (preferably 40 to 110) and an unsaturated equivalent of 15
0-3,000 (preferably 150-1,000) and number average molecular weight 30
It is advantageously 0 or more (preferably 1,000 to 30,000).

In the polymerizable unsaturated resin, when the acid value is lower than 20, the water dispersibility is poor, and when the acid value is higher than 300, the electrodeposition efficiency is lowered and the desired film thickness tends to be unobtainable. Further, when the unsaturated equivalent is less than 150, the film forming ability is reduced,
On the other hand, if it is more than 3,000, the curability tends to be lowered, and if it is less than about 300, the film-forming ability is lowered, which is not preferable in practice.

The glass transition temperature of the polymerizable unsaturated resin used in the photocurable electrodeposition coating composition (A) of the present invention when not exposed (hereinafter, referred to as Tg
Is preferably in the range of -50 to 60 ° C (preferably -20 to 40 ° C). If Tg is -50 ° C or less, the coating film during electrodeposition is too soft and the film resistance is small, and it is difficult to obtain a uniform coating film. On the other hand, if Tg is 60 ° C or more, the film resistance is large and the film thickness is large. There is a tendency that it is difficult to obtain a thickness, chain transfer does not easily occur during exposure, and photosensitivity deteriorates. The coating thickness of the first coat electrodeposition coating composition (A) is preferably in the range of 4 to 70 μm (preferably 5 to 50 μm). When the film thickness is 4 μm or less, it is easily affected by dissolved oxygen and surface oxygen in the resin and the photosensitivity is poor. On the other hand, when the film thickness is 70 μm or more, the electrodeposition coating film tends to be uneven and the surface smoothness is poor. Like

On the other hand, the resin component used in the second coat anionic electrodeposition coating composition (B) of the present invention may be either a polymerizable unsaturated resin or a saturated resin, and has a Tg of 20 ° C. or more (preferably 40) when unexposed. ~ 120 ° C) is required. Preferably, it is desirable that the Tg is designed to be higher than the Tg of the unsaturated resin used in the electrodeposition coating composition (A) by at least 5 ° C. When the Tg of the resin component used in the electrodeposition coating composition (B) is 20 ° C. or less, there is a drawback that the coating film and the film stick to each other after the contact exposure, and this tendency is remarkable especially when the temperature in the workplace is high. The coating thickness of the second electrodeposition coating composition (B) is 0.5 to 30 μm (preferably 1 to 10 μm).
The range is m). When the film thickness is 0.5 μm or less, the influence of the first coat appears on the surface, and when the Tg of the first coat is low, the surface sticks. On the other hand, when it exceeds 30 μm, the film resistance tends to increase and the coated surface tends to deteriorate. is there. The total film thickness of the two coats is preferably in the range of 5 to 70 μm (preferably 5 to 50 μm). If the film thickness is 5 μm or less, the etching resistance during copper etching tends to be poor, and if it is 70 μm or more, the smoothness of the surface tends to be unobtainable. It is preferable that the first coat is thick and the second coat is thin in consideration of photosensitivity.

The water-soluble or water-dispersible resin used in the second coat electrodeposition coating composition (B) of the present invention contains a saturated resin or an unsaturated resin as long as it contains an anionic group and has a glass transition temperature of 20 ° C. or higher. It is not limited to any of them, more preferably an acid value of 20 to 300 (preferably 40 to 110) and a number average molecular weight of 300.
It is a resin having the above (preferably 1,000 to 30,000).

As the unsaturated resin in the water-soluble or water-dispersible resin,
For example, it is selected from the resins (1) to (5) described in the electrodeposition coating composition (A), and the saturated resin is, for example, the polymerizable unsaturated group in the resin (1) to (5), that is, It may be a resin excluding an ethylenically unsaturated group. In the present invention, the resin used for the electrodeposition coating composition (B) is preferably an unsaturated resin because it does not reduce the photosensitivity of the coating film of the first coat.

The ethylenically unsaturated compound having one or more polymerizable unsaturated bonds in one molecule, which is used as an essential component or an optional component in the unsaturated resins (1) to (5), includes
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth)
Esters of (meth) acrylic acid such as acrylates;
Examples thereof include polyfunctional monomers such as ethylene glycol di (meth) acrylate and divinylbenzene; styrene (meth) acrylonitriles.

The electrodeposition composition used in the present invention includes a polymerizable unsaturated group-containing resin (for example, a polyester acrylate containing an ethylenically unsaturated group, a polyurethane resin, an epoxy resin, an acrylic resin, etc.) in addition to the resins described above as the resin binder. ), Saturated resin (eg, polyester resin, polyurethane resin, epoxy resin, acrylic resin, etc.), oligomer (eg, diethylene glycol di (meth) acrylate, etc.) to 100 parts by weight or less of resin, preferably 50 parts by weight or less. It is also possible to mix them in the range of not more than 10 parts to appropriately adjust the coating film performance.

In the present invention, the water-dispersion or water-solubilization of the polymerizable unsaturated or saturated resin is carried out by neutralizing the carboxyl group contained in the resin skeleton with an alkali (neutralizing agent). Examples of the neutralizing agent include alkanolamines such as monoethanolamine, diethanolamine and triethanolamine, triethylamine, diethylamine,
Alkylamines such as monoethylamine, diisopropylamine, trimethylamine, diisobutylamine,
Alkylalkanolamines such as dimethylaminoethanol, alicyclic amines such as cyclohexylamine,
Examples thereof include alkali metal hydroxides such as caustic soda and caustica, ammonia, and the like, and these can be used alone or as a mixture. The amount of the neutralizing agent used is preferably in the range of 0.4 to 1.0 equivalent with respect to 1 mol of the carboxy group contained in the skeleton. If the amount is less than 0.4 equivalent, the water dispersibility decreases and the electrodeposition coating becomes difficult, and the amount exceeds 1.0 equivalent. It is not preferable because it has poor storage stability.

In order to further improve the fluidity of the water-soluble or water-dispersed resin component, a hydrophilic solvent such as isopropanol, n-butanol, t-butanol, methoxyethanol, ethoxyethanol, butoxyethanol, diethylene glycol, methyl ether, dioxane, tetrahydrofuran. Etc. can be added. The hydrophilic solvent is preferably used in an amount of 300 parts by weight or less based on 100 parts by weight of the vehicle component.

Hydrophobic solvents, for example, petroleum-based solvents such as toluene and xylene; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and butyl acetate; 2-ethylhexyl in order to increase the coating amount on the object to be coated. Alcohols such as alcohol; and the like can also be added. The amount of hydrophobic solvent used is 200 per 100 parts by weight of the resin component.
A range of less than or equal to parts by weight is desirable.

The photopolymerization initiator used in combination with the unsaturated resin in the present invention is not particularly limited as long as it can initiate radical polymerization by active rays such as ultraviolet rays, and benzoin is a typical example. Benzoin methyl ether, benzoin ethyl ether, benzyl, diphenyl disulfide, tetramethyl thiuram monosulfide, diathicel, eosin, thionine, Michler's ketone, anthraquinone, chloranthraquinone, methyl anthraquinone, α-hydroxyisobutylphenone,
p-isopropyl α-hydroxyisobutylphenone, p
-Isopropyl α-hydroxyisobutylphenone, α ・
α'-dichloro-4-phenoxyacetophenone, 1-
Hydroxy 1-cyclohexylacetophenone, 2.2
Dimethoxy 2-phenylacetophenone, methylbenzoyl photomate, 2-methyl-1- [4- (methylthio) phenyl] -2.morpholinopropene, thioxanthone, benzophenone and the like can be mentioned. Is based on 100 parts by weight of resin component (solid content)
The range of 0.1 to 10 parts by weight is preferable, and if it is less than 0.1 parts by weight, the curability is deteriorated, which is not preferable, and if it exceeds 10 parts by weight, the mechanical strength of the cured film tends to deteriorate. Further, dyes and pigments can be added as required.

The electrodeposition coating for the printed wiring photoresist of the present invention is generally performed as follows.

The electrodeposition of the electrodeposition coating composition (A) is carried out by water-solubilizing or water-dispersing the composition (A) at a pH of 6.0 to 9 and a bath concentration (solid content concentration) of 3 to 25% by weight. %, Preferably 5 to 20% by weight, the bath temperature is controlled to 15 to 40 ° C., and preferably 15 to 30 ° C., and then an insulating substrate coated with copper foil in the thus controlled electrodeposition coating bath is used as an anode. It is performed by dipping and applying a direct current of a constant voltage (1 to 400 V) or a constant current of 1 to 400 mA / dm ² . A predetermined voltage or current may be applied after the start of energization, or may be gradually increased to the predetermined current or voltage in 1 to 30 seconds. In this case, 30 seconds to 5 minutes are suitable for the energization time.

After electrodeposition coating, the object to be coated is lifted from the electrodeposition bath and washed with water, and then dried as it is, or if necessary, by air blow, hot air, etc.

Then, using an electrodeposition composition (B) containing a polymerizable unsaturated resin or a saturated resin, which is a water-soluble or water-dispersed product, as the main component, in an electrodeposition coating bath controlled under the same conditions as above. And the electrodeposition coating under the same conditions as above. However, the electrodeposition time is preferably 10 seconds to 3 minutes. After pulling up the article to be coated from the electrodeposition bath and washing it with water, it is drained and dried as it is, or if necessary, by air blow, hot air or the like.

In a pair, a pattern mask is formed on the uncured photocurable electrodeposition coating film formed on the substrate and exposed with an actinic ray, and the unexposed portion other than the portion to be the conductor circuit is removed by the development treatment.

The actinic ray used for exposure in the present invention varies depending on the absorption amount of the photopolymerization initiator, but in general, a ray having a wavelength of 3,000 to 4,500Å is preferable. Sunlight as these light sources,
There are mercury lamps, xenon lamps and arc lamps. Curing of the coating film by irradiation of actinic rays is within a few minutes, usually 1 second to 20
It takes place in the range of minutes.

The developing treatment can be carried out by spraying weak alkaline water on the surface of the coating film to wash away the uncured portion of the coating film. As the weak alkaline water, water such as caustic soda, sodium carbonate, caustic potash, and ammonia water, which can neutralize the free carboxyl groups contained in the coating film to give water solubility, can be used. For example, in the case of caustic soda aqueous solution, about 0.1 to 5% is suitable. If it is less than 0.1%, development is difficult, and if it is more than 5%, the image area may be dipped, which is not preferable.

Then, the copper foil portion (non-circuit portion) exposed on the substrate by the developing treatment is removed by a usual etching treatment using ferric chloride or the like. After that, the photo-cured coating film on the circuit pattern is also dissolved and removed by a strong alkali such as caustic soda to form a printed circuit on the substrate.

[Effects] The present invention applies a photocurable electrodeposition coating composition having a low glass transition temperature onto a copper foil by anion electrodeposition method, and after washing with water or washing with water and drying, the coating film with a high glass transition temperature is applied. A two-coat electrodeposition coating method in which a coating composition is applied to obtain a printed wiring photoresist. Since this coating film has no surface tackiness, it is most suitable for film contact exposure and, surprisingly, it has the effect that the photosensitivity is higher than in the case of one-coat electrodeposition coating and the exposure amount is small. Further, the unexposed portion of the coating film formed by the method of the present invention is developed in a short time by a weak alkali, the exposed portion is also excellent in etching resistance, and easily dissolved and removed in a short time by a strong alkali. You can

[Examples] Hereinafter, the present invention will be described in more detail with reference to Examples.

Production Example 1 35 parts by weight of methyl methacrylate, 45 butyl acrylate
Parts by weight, 20 parts by weight of acrylic acid and 2 parts by weight of azobisisobutyronitrile were added to 90 parts by weight of propylene glycol monomethyl ether (hydrophilic solvent) maintained at 110 ° C. under a nitrogen gas atmosphere for 3 hours. It dripped in need. After the dropping, the mixture was aged for 1 hour, a mixed solution of 1 part by weight of azobisdimethylvaleronitrile and 10 parts by weight of propylene glycol monomethyl ether was added dropwise over 1 hour, and the mixture was aged for 5 hours to obtain a high acid value acrylic resin (acid. 155) solution was obtained. Next, 24 parts by weight of glycidyl methacrylate, 0.12 part by weight of hydroquinone and 0.6 part by weight of tetraethylammonium bromide were added to this solution, and the mixture was reacted at 110 ° C. for 5 hours while blowing air to obtain a polymerizable unsaturated resin (acid value: about 50, A solution having a saturation equivalent of about 740 and a number average molecular weight of about 20,000 Tg of about 5 ° C.) was obtained. After neutralizing 0.6 equivalent of this polymerizable unsaturated resin with triethylamine, 6 parts by weight of α-hydroxyisobutylphenone was added as a photoinitiator, and then water was added so that the solid content was 10% by weight. The coating bath (pH 7.0) was used.

Production Example 2 A mixed solution of 10 parts by weight of styrene, 30 parts by weight of n-butyl methacrylate, 30 parts by weight of methyl acrylate, 30 parts by weight of acrylic acid and 3 parts by weight of azobisisobutyronitrile was heated to 120 ° C. under a nitrogen gas atmosphere. It was added dropwise to 90 parts by weight of the retained cellosolve over 3 hours. After dropping
Aged for 1 hour, added dropwise a mixed solution consisting of 1 part by weight of azobisdimethylvaleronitrile and 10 parts by weight of cellosolve over 1 hour, and further aged for 5 hours to obtain a high acid value acrylic resin (acid value 233) solution. It was Next, 35 parts by weight of glycidyl methacrylate, 0.13 parts by weight of hydroquinone, and 0.6 parts by weight of tetraethylammonium bromide were added to this solution, and the mixture was reacted at 110 ° C. for 5 hours while blowing in air to obtain a photocurable resin (acid value about 70, unsaturated). 1.83 mol / kg, Tg 25 ℃
A solution having a number average molecular weight of about 15,000 was obtained.

After neutralizing 0.6 equivalent of this polymerizable unsaturated resin with triethylamine, 6 parts by weight of α-hydroxyisobutylphenone was added as a photoinitiator, and the solid content was 10% by weight.
Water was added to the solution to prepare an electrodeposition coating bath (pH 7.1).

Production Example 3 40 parts by weight of methyl methacrylate, 25 butyl acrylate
100 parts by weight of dioxane (hydrophilic solvent) in which a mixed system consisting of 1 part by weight, 15 parts by weight of 2-hydroxyethyl methacrylate, 20 parts by weight of acrylic acid and 2 parts by weight of azobisisobutyronitrile was kept at 105 ° C under a nitrogen gas atmosphere. The solution was added dropwise to the unit 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, to 200 parts by weight of this solution, 20 parts by weight of an equimolar adduct of 2-hydroxyethyl methacrylate and tolylene diisocyanate are added, and the mixture is reacted in a nitrogen gas atmosphere at a temperature of 80 ° C. for 5 hours to obtain a polymerization usable in the present invention. Unsaturated resin (acid value about 120, unsaturated equivalent about 1,800, number average molecular weight about 2
A solution of 2,000 Tg (about 20 ° C) was obtained. After neutralizing 0.6 equivalent of this polymerizable unsaturated resin with dimethylaminoethanol, 6 parts by weight of benzoin ethyl ether was added as a photoinitiator, and then water was added so that the solid content became 10% by weight, and electrodeposition was performed. It was used as a coating bath (pH 7.2).

Production Example 4 Epicoat No.828 (trade name, manufactured by Ciel Chemical Co., Ltd.) 390
A mixed system of 1 part by weight of linseed oil and 1120 parts by weight of linseed oil is subjected to an esterification reaction in a nitrogen gas atmosphere at a temperature of 220 to 230 ° C. until the acid value becomes 10 or less, and then the temperature is lowered to 80 ° C. Add 392 parts by weight of maleic acid and raise the temperature again to 230 ° C.
The temperature was gradually raised to 0, and the maleination reaction was carried out at the same temperature for about 2 hours. Next, the temperature is lowered to 180 ° C., 300 parts by weight of n-butanol is added to open the acid anhydride group, and the vehicle component usable in the present invention (acid value about 100, unsaturated equivalent about 2
50, number average molecular weight about 2,000, Tg 5 ° C.) were obtained.

After dissolving it in ethylene glycol monobutyl ether (hydrophilic solvent) so that the content of the vehicle component is 70% by weight, neutralize it with 0.6 equivalent of triethylamine, and add 5% by weight of benzoin ethyl ether (based on the vehicle component). After that, water was added so that the solid content was 10% by weight to prepare an electrodeposition coating bath (pH 8.5).

Production Example 5 The same procedure as in Production Example 1 was repeated except that butyl methacrylate was used instead of butyl acrylate in Production Example 1. The Tg of this resin is 50 ° C.

Manufacture example 6 It replaced with the butyl acrylate of manufacture example 3, it changed into ethyl methacrylate, and it carried out by the same method as manufacture example 3. The Tg of this resin is 70 ° C.

Production Example 7 40 parts by weight of methyl methacrylate, ethyl methacrylate
Dioxane (hydrophilic solvent) 100 in which a mixed system consisting of 35 parts by weight, 15 parts by weight of 2-hydroxyethyl methacrylate, 10 parts by weight of acrylic acid and 2 parts by weight of azobisisobutyronitrile was kept at 105 ° C. in a nitrogen gas atmosphere. The solution was added dropwise to 3 parts by weight over 3 hours and aged at the same temperature for 1 hour to obtain an acrylic resin (acid value 75, Tg 65 ° C.) solution.
The resin was neutralized with 0.6 equivalents of triethylamine, and water was added so that the solid content was 10% by weight to prepare an electrodeposition coating bath (pH 7.3).

Example 1 Using the electrodeposition coating bath of Production Example 1, a copper-clad laminate for printed wiring (100 × 200 × 1.6 m) having through holes of 0.4 mm and 6 mm was used.
m) as an anode, and a direct current of 100 V was applied for 3 minutes at a bath temperature of 25 ° C to perform electrodeposition coating, the coating film was washed with water and dried at 70 ° C for 2 minutes to obtain a 30 μm-thick smooth photosensitive film. . Then, using the electrodeposition coating bath of Production Example 5, a direct current of 120 V was applied at a bath temperature of 25 ° C. for 1 minute for electrodeposition coating, and then the coating film was washed with water and dried at 70 ° C. for 5 minutes. A smooth photosensitive film having two coats with a total thickness of 33 μm, which did not accumulate in the through holes and had no surface tackiness, was obtained. Next, the negative film was brought into close contact with this coated plate by a vacuum device at room temperature of 25 ° C., and both sides were irradiated with ultraviolet rays (hereinafter abbreviated as UV) using a 3 Kw ultra-high pressure mercury lamp.

Example 2 Using the electrodeposition coating bath of Production Example 2, a copper clad laminate for printed wiring having through holes of 0.4 mm and 0.6 mm (100 × 200 × 1.
6mm) as the anode, and at bath temperature 25 ℃, 60mA / dm for copper clad laminate
A direct current of ² was applied for 3 minutes for electrodeposition coating. The maximum voltage at this time was 70V. Rinse the film with water and air dry it to 20
A smooth photosensitive film having a thickness of μ was obtained. Then, using the electrodeposition coating bath of Production Example 5, a direct current of 100 V was applied for 2 minutes at a bath temperature of 25 ° C. to perform electrodeposition coating, and then the coating film was washed with water and dried at 70 ° C. for 5 minutes. A two-coat, 30 μm thick, through-hole was obtained to obtain a smooth photosensitive film having no accumulation in the through holes and no surface tackiness. Then room temperature 25
The negative film is attached to this coated plate with a vacuum device at 3
Using an ultra-high pressure mercury lamp of w, ultraviolet rays (hereinafter, UV
Abbreviated).

Example 3 In Example 2, the same treatment as in Example 2 was carried out by using the electrodeposition coating bath of Production Example 7 instead of the electrodeposition coating bath of Production Example 5 used for the second coat. The total film thickness of these two coats is
It was 23 μm, and it was not accumulated in the through hole and had no surface tackiness.

Example 4 A copper clad laminate for printed wiring having through holes of 0.4 mm and 0.6 mm using the electrodeposition coating bath of Production Example 3 (100 × 200 × 1.
6mm) as the anode and 50mA / dm for the copper clad laminate at a bath temperature of 25 ℃.
A direct current of ² was applied for 3 minutes for electrodeposition coating. The maximum voltage at this time was 60V. This coating film was washed with water and dried at 70 ° C. for 2 minutes to obtain a smooth photosensitive film having a thickness of 15 μm. Then, using the electrodeposition coating bath of Production Example 6, a direct current of 100 V was applied for 2 minutes at a bath temperature of 25 ° C. for electrodeposition coating, and then the coating film was washed with water and heated at 70 ° C. for 5 minutes.
Dry for minutes. A two-coat, 20 μm thick through-hole was obtained, and a smooth photosensitive film having no surface tackiness and no accumulation was obtained.
Next, UV irradiation was performed in the same manner as in Example 1.

Example 5 The same procedure as in Example 4 was carried out using the electrodeposition coating bath of Production Example 4 instead of the electrodeposition coating bath of Production Example 3 used for the first coat of Example 4. The total film thickness of the two coats was 25 μm, and there was no accumulation in the through holes and no surface tackiness.

Comparative Example 1 Using the coated plate of Example 1 having only one coat, UV irradiation was performed in the same manner as in Example 1.

Comparative Example 2 UV irradiation was performed in the same manner as in Example 1 using the coated plate of Example 2 having only one coat.

Comparative Example 3 Using the copper clad laminate used in Example as an anode, and using the electrodeposition coating bath of Production Example 5 at a bath temperature of 25 ° C., a DC current of 60 mA / dm ² was applied to the plate for 4 minutes to generate electricity. Maximum voltage at this time is 11
It was 0V. Wash this coating with water and dry at 70 ° C for 5 minutes.
A smooth photosensitive film having a thickness of μ was obtained. Next, in the same manner as in Example 1,
UV irradiation was performed. Attempts were made to make it thick, but at 25 μm, plague was caused and the coating film was destroyed.

Comparative Example 4 Dip coating was carried out on the coated plate of Example 2 having only one coat so that the solid content of the coating material of Production Example 2 was 2%, and then the coating was dried at 70 ° C. for 10 minutes. The film thickness after two coats was 22 μm. In this case, the resin was accumulated in the through hole and remained thick.

Comparative Example 5 The coating material of Production Example 7 was applied onto the coated plate of Example 2 having only one coat by a roll coater, and then dried at 70 ° C. for 10 minutes. Two
The film thickness after coating was 25 μm. In this case as well, the resin was thick and remained in the through holes.

Comparative Example 6 Using the coated plate of Example 4 having only one coat, UV irradiation was performed in the same manner as in Example 1.

Comparative Example 7 The copper clad laminate used in Example was used as an anode, the electrodeposition coating bath of Production Example 6 was used, and a DC current of 60 mA / dm ² was applied to the plate for 3 minutes at a bath temperature of 25 ° C. to generate electricity. The maximum voltage at this time is
It was 130V. Wash this coating with water and dry at 70 ° C for 5 minutes
A smooth photosensitive film having a thickness of 10 μm was obtained. Next, UV irradiation was performed in the same manner as in Example 1. An attempt was made to apply it thickly, but at a thickness of 15 μm, prepreg was caused and the coating film was destroyed.

Negative film of Examples 1 to 5 and Comparative Examples 1 to 7 The degree of peeling of the negative film after the exposure, the exposure amount, the unexposed area was washed out with a weak alkali, developed, washed with water, and then the copper foil with ferric chloride was used. The removal of the etching treatment, the peeling of the cured coating film in the exposed area, and the state of the pattern as a printed circuit board were examined. The results are shown in Table 1 below.

Exposure dose The minimum exposure dose of a 200 μm image line that develops into a firm cured film after development (total light intensity at 375 nm mJ / c
m ² ) Development 25 ° C., 1% sodium carbonate solution sprayed for 2 minutes, after washing out the unexposed area.

Etching treatment removal After exposure, development and washing with water until the inside of the through hole is cured, 50
℃, the state of the surface and the inside of the through hole after spraying ferric chloride solution for 3 minutes.

Peeling The peeled state of the cured film after spraying 3% caustic soda solution at 50 ° C for 3 minutes.

Pattern status as a printed circuit board We checked whether the required circuit was properly formed.

Front Page Continuation (72) Inventor Yu Akagi 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd. In-house (56) References JP-A-54-68224 (JP, A) JP-A-62-187848 (JP, A)

Claims (1)

[Claims] 1. A water-soluble or water-dispersible resin having a glass transition temperature of 20 ° C. or higher after electrodeposition coating a photocurable anionic electrodeposition coating composition (A) on a copper clad laminate. An electrodeposition coating method for a printed wiring photoresist, which comprises electrodepositing an anion electrodeposition coating composition (B) containing as a main component.