JPH0769613B2 - Cation type electrodeposition coating method for printed wiring photoresist - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cationic electrodeposition coating method for printed wiring photoresists, and more particularly, to a copper-clad laminate coated by electrodeposition to obtain a smooth surface without surface tackiness. The present invention relates to a two-coat cationic electrodeposition coating method for a printed wiring photoresist, which can form a coating film and can be 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 cationic electrodeposition coating composition (A) is electrodeposited on a copper clad laminate, the coating film is further coated with a cationic type resin having a glass transition temperature of 20 ° C. or higher. Provided is a cationic electrodeposition coating method for a printed wiring photoresist, which comprises electrodepositing a cationic electrodeposition coating composition (B) containing a water-soluble or water-dispersible resin as a main component.

The photocurable cationic electrodeposition coating composition (A) in the method of the present invention is basically a composition containing a cationic water-soluble or water-dispersible polymerizable unsaturated resin and a photopolymerization initiator as main components. Is. 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 a cationic group, and typical examples thereof will be shown 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,
Polymerizable unsaturated resin obtained by adding to an acrylic resin having a hydroxyl group and a tertiary amino group in the resin skeleton: Examples of compounds having a polymerizable unsaturated bond and a hydroxyl group in one molecule include 2-hydroxyethyl acrylate and 2 -Hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, N-methylol acrylamide, allyl alcohol, methallyl alcohol and the like are included, and examples of the diisocyanate compound include tolylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate and lysine diisocyanate.

The introduction of a hydroxyl group into the acrylic resin skeleton is imparted by using the above-mentioned compound having a polymerizable unsaturated bond and a hydroxyl group in one molecule as a copolymerization component. Further, the introduction of a tertiary amino group into the acrylic resin skeleton can be achieved by using the following general formula as a copolymerization component. In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents C
_{1 to 8} represents an alkylene group, and R ₃ and R ₄ are each C
_{A tertiary} alkyl group having _{1 to 4} alkyl groups such as dialkylaminoalkyl (meth) acrylates (for example, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, etc.) It is carried out by using a polymerizable unsaturated monomer having an amino group.

(2) After reacting an epoxy group of an epoxy resin having two or more epoxy groups in one molecule with a compound partially containing a secondary amino group, the remaining epoxy group is polymerized with (meth) acrylic acid or the like. Unsaturated monocarboxylic acid or a tertiary amino group-containing unsaturated resin obtained by reacting with a compound having a polymerizable unsaturated group and a hydroxyl group in one molecule exemplified in (1) above: As an epoxy resin, for example, one molecule A copolymer of a compound having a polymerizable unsaturated group and a glycidyl group with another polymerizable unsaturated monomer; a diglycidyl ether of polyphenol such as bisphenol A and bisphenol F, or a polyphenol, polyester, poly Reaction products with ether polyols, etc .; novolak phenol, novolak cresol type epoxy resin, aliphatic polyepoxy resin, alicyclic Polyepoxy resins or their polyester, such as by modified product polyether polyol or mixtures thereof; and the like.

The compound containing a secondary amino group is represented by the following general formula: In the formula, each of R ₁ and R ₂ represents a C _1-18 alkyl group or an aromatic group, or an alkylamine or an aromatic amine represented by: (for example, dimethylamine, diethylamine, di-n-propylamine, diphenylamine, etc.) ); Also, the following general formula In the formula, R ₁ represents the above meaning, n represents an integer of 1 to 18 and m represents an integer of 0 to 20 (eg, n-methylethanolamine, diethanolamine, diisopropanolamine, etc.) ); And the like.

(3) A compound having a polymerizable unsaturated group and a glycidyl group in one molecule (for example, glycidyl (meth) acrylate)
And a compound having a polymerizable unsaturated group and a tertiary amino group in one molecule (for example, N, N-dimethylaminoethyl (meth))
Acrylic, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, etc.) are copolymerized with other polymerizable monomers to obtain resins that are polymerized with (meth) acrylic acid, etc. A tertiary amino group-containing unsaturated resin obtained by reacting a monocarboxylic acid having an unsaturated group or a compound having a polymerizable unsaturated group and a hydroxyl group in one molecule exemplified in (1) above; The epoxy group of the epoxy resin exemplified in 2) is partially reacted with a compound having a polymerizable unsaturated group and a carboxyl group or a hydroxyl group in one molecule exemplified in the above (1) and (2), and then the remaining epoxy group An onium base-containing unsaturated resin obtained by onium chloride with a tertiary amino compound, thioether, phosphine and the like and a carboxylic acid; ), A compound having a polymerizable unsaturated group and a carboxyl group or a hydroxyl group in one molecule is used instead of onium chloride after partially esterifying the epoxy group, such as a tertiary amino group-containing compound described above. An onium base-containing unsaturated resin obtained by simultaneously reacting a forming compound or, if necessary, a carboxylic acid with an epoxy resin;

These resins may be used alone or in combination of two or more.

The cationic type polymerizable unsaturated resin represented by the above (1) to (5) has a tertiary amino group and / or onium base content of 0.2 to 5 mol, preferably 0.3 to 2.0 mol, per 1 kg of resin. Saturation equivalent is 150 to 3,000, preferably 150 to 1,000,
And a number average molecular weight of 300 or more, preferably 1,000 to 30,000
Is advantageous.

In such an unsaturated resin, if the tertiary amino group and / or onium base content is less than 0.2 mol / kg resin, the water dispersibility is poor, and if it is more than 5 mol / kg resin, the electrodeposition efficiency is lowered, There is a tendency that a desired film thickness cannot be obtained. Further, if the unsaturated equivalent is less than 150, the coating film forming ability decreases, while if it is more than 3,000, the curability tends to decrease, and if the number average molecular weight is less than about 300, the coating film forming ability decreases. It is not preferable.

The cationic type polymerizable unsaturated resin used in the photocurable cationic electrodeposition coating composition (A) of the present invention has an unexposed glass transition temperature (hereinafter referred to as Tg) of −50 to 60 ° C. (preferably −20). -40 ° C) is advantageous. Tg is -50
If the temperature is lower than ℃, the coating film will be too soft during electrodeposition and the film resistance will be small, making it difficult to obtain a uniform coating film. There is a tendency that it is difficult and chain transfer does not easily occur during exposure, resulting in poor photosensitivity. 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 cationic electrodeposition coating composition (B) of the present invention may be either a polymerizable unsaturated resin or a saturated resin as long as it is a cationic type resin, and has a Tg of 20 when unexposed. It is necessary that the temperature is not lower than 0 ° C (preferably 40 to 120 ° C). Preferably, it is desirable to design the Tg to be at least 5 ° C. higher than the Tg of the unsaturated resin used in the cationic electrodeposition coating composition (A). 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 coat of the cationic electrodeposition coating composition (B) is in the range of 0.5 to 30 μm (preferably 1 to 10 μm). 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, while on the other hand, 30
If it exceeds μm, the film resistance tends to be high and the coated surface tends to be poor. The total film thickness of 2 coats is 5 to 70 μm
It is preferably in the range of (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 cationic water-soluble or water-dispersible resin used in the second coat cationic electrodeposition coating composition (B) of the present invention is a saturated resin as long as it contains a cationic group and has a glass transition temperature of 20 ° C. or higher. It is not limited to any of unsaturated resins, more preferably an amino group and / or onium base content 0.2 to 5.0 mol / kg resin, preferably 0.3 to 2.0 mol / kg
Resin and number average molecular weight of 300 or more, preferably 1,000 to 30,0
It is a resin having 00.

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

In the cationic electrodeposition coating compositions (A) and (B) used in the present invention, a polymerizable unsaturated group-containing resin (for example, a polyester acrylate containing an ethylenically unsaturated group, in addition to the resin described above as a resin binder, Polyurethane resin, epoxy resin, acrylic resin etc.), saturated resin (eg polyester resin, polyurethane resin, epoxy resin, acrylic resin etc.), oligomer (eg diethylene glycol di (meth) acrylate etc.), one or more ethylenically unsaturated groups Unsaturated compounds (eg, (meth) acrylic acid ester, ethylene glycol di (meth) acrylate, divinylbenzene, etc.) contained are 100 parts by weight or less, preferably 50 parts by weight or less, based on 100 parts by weight of the resin. It is also possible to properly adjust the coating performance by blending with.

In the present invention, the polymerizable unsaturated or saturated resin is water-dispersed or water-solubilized by neutralizing the amino group with an acid (neutralizing agent) when an amino group is introduced into the resin skeleton. Examples of the neutralizing agent include formic acid, acetic acid,
Examples include monocarboxylic acids such as lactic acid, hydroxyacetic acid, and butyric acid, and these can be used alone or as a mixture. The amount of the neutralizing agent used is preferably in the range of 0.2 to 1.0 equivalent with respect to 1 mol of the amino group contained in the skeleton. When the amount is less than 0.2 equivalent, the water dispersibility and storage stability decrease, and when it exceeds 1.0 equivalent, it is generally The electrodeposition efficiency is lowered and it becomes difficult to obtain a desired film thickness.

In the case of an onium base-containing resin, it is water-dispersed or water-solubilized by diluting it with water as it is.

In order to further improve the fluidity of the water-solubilized or water-dispersed resin component, a hydrophilic solvent such as isopropanol,
It is possible to add n-butanol, t-butanol, methoxyethanol, ethoxyethanol, butoxyethanol, diethylene glycol, methyl ether, dioxane, tetrahydrofuran and the like. 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, diacetyl, eosin, thionine, Michler's ketone, anthraquinone, chloranthraquinone, methylanthraquinone, α-hydroxyisobutylphenone,
p-isopropyl α-hydroxyisobutylphenone, α
.Alpha .'- dichloro-4-phenoxyacetophenone, 1-
Hydroxy 1-cyclohexylacetophenone, 2.2
Examples thereof include dimethoxy 2-phenylacetophenone, methylbenzoyl photomate, 2-methyl-1- [4- (methylthio) phenyl] -2.morpholinopropene, thioxanthone, and benzophenone. 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.

As the photopolymerization initiator, a water-insoluble one is preferable because a uniform proportion with the resin causes electrodeposition precipitation. Further, dyes and pigments can be added as required.

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

The electrodeposition of the cationic electrodeposition coating composition (A) is carried out by adjusting the pH of an electrodeposition coating bath obtained by water-solubilizing or water-dispersing the composition (A).
6.0-9, bath concentration (solid content concentration) 3-25% by weight, preferably 5-20% by weight, bath temperature 15-40 ° C, preferably 15-30 ° C
Then, the insulating substrate coated with copper foil is immersed as a cathode in the electrodeposition coating bath controlled in this way as a cathode, and a constant voltage (1
~ 400 V) or a constant current of 1 to 400 mA / dm ² is applied. 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, a cationic electrodeposition coating composition (B) containing a polymerizable unsaturated resin or a saturated resin, which is a water-soluble or water-dispersed product, is used as an electrodeposition coating under the same conditions as described above. Immerse in the bath and perform 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.

Then, 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 a conductor circuit is removed by a developing process.

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.

Further, the development treatment may be carried out by washing the uncured portion of the coating film by spraying water or weak acid water when an onium base-containing resin is used, and in other cases spraying weak acid water on the surface of the coating film. it can. Weak acid water is usually formic acid, acetic acid,
A dilute aqueous solution of a monocarboxylic acid such as lactic acid or hydroxyacetic acid, a dilute aqueous solution of an inorganic acid such as hydrochloric acid, or the like that can neutralize the free amino groups contained in the coating film to give water solubility can be used. For example, in the case of acetic acid aqueous solution, 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 monocarboxylic acid or an inorganic acid having a higher concentration than that used in the development process, and a printed circuit is formed on the substrate.

[Effect] In the present invention, a photocurable electrodeposition coating composition having a low glass transition temperature is applied onto a copper foil by a cationic electrodeposition coating method, washed with water or washed with water and dried, and the coating film having a high glass transition temperature is further applied. It is a two-coat electrodeposition coating method for obtaining a printed wiring photoresist by applying an electrodeposition coating composition. 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 acid, and the exposed portion is also excellent in etching resistance, and easy in a short time by an acid or strong alkali stronger than the developing solution. Can be dissolved and removed.

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

Production Example 1 30 parts by weight of methyl methacrylate, 35 butyl acrylate
Parts by weight, 35 parts by weight of glycidyl methacrylate, 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 containing 1 part by weight of azobisdimethylvaleronitrile and 10 parts by weight of propylene glycol monomethyl ether was added dropwise over 1 hour, and then aged for 5 hours to obtain a glycidyl group-containing acrylic resin solution. Obtained. Next, 10 parts by weight of acrylic acid, 0.12 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 air, and then 5
Cool to 0 ° C and add 8.0 parts by weight of methylaminoethanol 70
The reaction was carried out for 2 hours at 0 ° C. to obtain a tertiary amino group-containing polymerizable unsaturated resin (amino group-containing about 0.91 mol / kg, unsaturated equivalent about 850, number average molecular weight about 20,000, Tg about 6 ° C.) solution. After neutralizing 0.6 equivalent of this polymerizable unsaturated resin with acetic acid, 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 6.7) was used.

Production Example 2 30 parts by weight of glycidyl methacrylate, 5 parts by weight of styrene, 24 parts by weight of n-butyl methacrylate, 23 parts by weight of methyl acrylate, dimethylaminoethyl methacrylate
A mixed solution of 18 parts by weight and 5 parts by weight of azobisisovaleronitrile was added dropwise to 90 parts by weight of cellosolve kept at 80 ° C. in a nitrogen gas atmosphere over 3 hours. 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 cellosolve was added dropwise over 1 hour, and the mixture was aged for 5 hours to obtain an acrylic resin solution. Next, 15 parts by weight of acrylic acid and 0.13 parts by weight of hydroquinone were added to this solution and reacted at 110 ° C. for 5 hours while blowing air to obtain a photocurable resin (amino group content about 1.0 mol / kg, unsaturated equivalent 545 , Tg20 ° C., number average molecular weight about 15,000) to obtain a solution.

After neutralizing 0.6 equivalent of this polymerizable unsaturated resin with formic acid, 6 parts by weight of α-hydroxyisobutylphenone was added as a photoinitiator, and water was added so that the solid content was 10% by weight. The coating bath (pH 6.5) was used.

Production Example 3 35 parts by weight of methyl methacrylate, 20 butyl acrylate
Dioxane (hydrophilic solvent) in which a mixed system consisting of 1 part by weight, 15 parts by weight of 2-hydroxyethyl methacrylate, 30 parts by weight of dimethylaminoethyl methacrylate and 2 parts by weight of azobisisobutyronitrile was kept at 105 ° C under a nitrogen gas atmosphere. It was added dropwise to 100 parts by weight over 2 hours and further aged at the same temperature for 1 hour to obtain an acrylic resin solution. Then, 20 parts by weight of an equimolar adduct of 2-hydroxyethyl methacrylate and tolylene diisocyanate was added to 200 parts by weight of this solution, and the mixture was reacted at a temperature of 80 ° C. for 5 hours to prepare a polymerizable unsaturated resin usable in the present invention ( Tertiary amino group content about 1.6 mol / kg, unsaturated equivalent about 20,000, Tg
A solution of about 22 ° C.) was obtained. This polymerizable unsaturated resin was treated with acetic acid.
After neutralization by 0.6 equivalent, 6 parts by weight of benzoin ethyl ether was added as a photoinitiator, and then water was added so that the solid content was 10% by weight to prepare an electrodeposition coating bath (pH 6.3).

Production Example 4 Epicoat No. 1001 (trade name, manufactured by Ciel Chemical Co., Ltd.) 960
Parts by weight, 115 parts by weight of acrylic acid, 0.8 parts by weight of hydroquinone and 3 parts by weight of tetraethylammonium bromide were added to 350 parts by weight of butyl cellosolve, and an esterification reaction was carried out at 110 ° C. while blowing air until the acid value became 1 or less. After that, the temperature is lowered to 50 ° C., 36 parts by weight of dimethylaminoethanol and 24 parts by weight of acetic acid are added, and the mixture is reacted at 70 ° C. for 4 hours to obtain a quaternary ammonium salt group-containing unsaturated resin (quaternary ammonium salt group content of about 0.35 mol / kg, Unsaturated equivalent of about 720,
A number average molecular weight of about 1,200 and Tg of 10 ° C) was obtained.

5% by weight of benzoin ethyl ether in this unsaturated resin
After adding (to the vehicle component), water is added so that the solid content is 10% by weight, and the electrodeposition coating bath (pH 7.
8)

Production Example 5 The procedure of Production Example 1 was repeated except that butyl methacrylate was used instead of butyl acrylate of Production Example 1. The Tg of this resin is 52 ° C.

Production Example 6 The procedure of Production Example 3 was repeated except that ethyl methacrylate was used instead of butyl acrylate of Production Example 3. The Tg of this resin is 72 ° C.

Production Example 7 35 parts by weight of methyl methacrylate, ethyl methacrylate
30 parts by weight, 15 parts by weight of 2-hydroxyethyl methacrylate, 20 parts by weight of dimethylaminoethyl methacrylate and 2 parts by weight of azobisisobutyronitrile were mixed at 105 ° C. in a nitrogen gas atmosphere to maintain dioxane (hydrophilic solvent). ) It was added dropwise to 100 parts by weight over 3 hours and further aged at the same temperature for 1 hour to obtain an acrylic resin (tertiary amino group content 1.3 mol / kg, Tg 65 ° C.) solution. After neutralizing 0.6 equivalent of this resin with acetic acid, water was added so that the solid content was 10% by weight, and an electrodeposition coating bath (pH 6.
5)

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 a cathode and a DC current of 100 V for 3 minutes at a bath temperature of 25 ° C. for electrodeposition coating, the coating film was washed with water and dried at 70 ° C. for 2 minutes to obtain a 30 μm 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 cathode and 60mA / 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 70V. 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 23μ and there was no surface tackiness accumulated in the through holes.

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 cathode 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 120 V was applied for 1 minute at a bath temperature of 25 ° C. to carry out electrodeposition coating, and then the coating film was washed with water and kept 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 a cathode, 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 mol / l aqueous solution of lactic acid was sprayed for 2 minutes, and the unexposed area was washed out.

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 mol / l lactic acid aqueous solution at 50 ° C for 3 minutes.

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

(72) Inventor Naozumi Iwasawa 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd. (72) Inventor Yuo Akagi 4-1-1, Higashi-Hachiman, Hiratsuka, Kanagawa In-house (72) Inventor Toshio Kondo 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd. (56) Reference JP-A-54-68224 (JP, A) JP-A-62-187848 (JP) , A)

Claims (1)

[Claims] 1. A photocurable cationic electrodeposition coating composition (A) is electrodeposited on a copper-clad laminate, and then a cationic water-soluble or water-dispersion having a glass transition temperature of 20 ° C. or higher is further applied on the coating film. A cationic electrodeposition coating method for a printed wiring photoresist, which comprises electrodepositing a cationic electrodeposition coating composition (B) containing a polymerizable resin as a main component.