JPH02218472A - Formation of thermosetting solid resin layer, formation of cured resin layer and method for electromagnetic shielding of printed wiring board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a method for forming a thermosetting solid resin on the surface of a substrate, particularly on the surface of a printed wiring board used for televisions, radios, computers, world processors, etc., and a method for forming a cured resin layer. The present invention relates to a method for forming a printed wiring board and a method for electromagnetically shielding a printed wiring board using these methods.

(Prior art and its problems) It is known that in order to obtain an electromagnetically shielded printed wiring board, an insulating layer is formed on the board and an electromagnetic shielding layer is provided thereon (Utility Model Publication No. 55-29276). Publication No.)
, Since such a board is itself electromagnetic shielded, it can obtain a large shielding effect,
There are advantages such as no need for special shield wires, shield plates, shield cases, etc.

By the way, when forming an insulating layer on a substrate, conventionally, thermosetting phenol resin or epoxy resin is printed by a printing method and then heat-treated. However, in the conventional printing method, since the thermosetting resin is applied to the substrate in only one printing process, there is a problem that the possibility of pinholes occurring is extremely high. In addition, in order to suppress the occurrence of pinholes, when trying to apply thermosetting resin in multiple printing processes using the conventional method, there is a step in which thermosetting resin is applied according to the number of printing processes. It becomes very complicated as it has to be done repeatedly.
Such a method cannot be said to be industrially practical.

According to JP-A-63-154780, a composition (I) consisting of a thermosetting epoxy methacrylate resin obtained by addition-reacting methacrylic acid to an epoxy resin, a copolymerizable crosslinking agent, and a thermal polymerization initiator, and an epoxy resin An adhesive composition obtained by kneading a filler and a thixotropic agent into a mixture of composition (II) consisting of a curing agent and a hardening agent is applied onto a substrate by a printing method, and the composition (1) is heated at a low temperature. A method is described in which a thermosetting solid resin layer is formed by reaction and then the solid resin layer is thermoset. However, this publication does not mention repeating the printing process multiple times in order to suppress the occurrence of pinholes, and this method uses low-humidity heat treatment to form the thermosetting solid resin layer. Therefore, it takes time to form the solid resin layer, and
It is difficult to obtain a uniform solid resin layer with good reproducibility;
Moreover, it is troublesome to operate.

(Problem of the Invention) The present invention provides a method for efficiently forming a thermosetting solid resin layer on the surface of a substrate in which the occurrence of pinholes is suppressed.

The object of the present invention is to provide a method for efficiently forming a cured resin layer and a method for electromagnetic shielding of a printed wiring board using these methods.

(Means for Solving the Problems) The present inventors have conducted extensive research to solve the above problems, and as a result, have completed the present invention.

That is, according to the present invention, a polymerizable compound containing an epoxy resin and a polyfunctional (meth)acrylic acid ester-based polymerizable compound as at least a part of the polymerizable component on the surface of the substrate;
A thermosetting solid is applied to the surface of a substrate by repeatedly applying a liquid composition containing a curing agent for the epoxy resin and a photopolymerization initiator for the polymerizable compound by a printing method and irradiating it with actinic rays. A method of forming a resin layer is provided.

According to the present invention, an epoxy resin, a polymerizable compound containing a polyfunctional (meth)acrylic acid ester polymerizable compound as at least a part of the polymerizable component, and a curing agent for the epoxy resin are provided on the printed wiring board. A thermosetting solid resin layer is formed on the printed wiring board by repeatedly applying a liquid composition containing a photopolymerization initiator for the polymerizable compound by a printing method and irradiating it with actinic rays. ,
There is provided a method for electromagnetic shielding of a printed wiring board, characterized in that the thermosetting solid resin layer is then subjected to a heat treatment to form a cured resin layer, and a conductive layer is formed on the surface of the cured resin layer.

Furthermore, according to the present invention, an epoxy resin, a polymerizable compound containing a polyfunctional (meth)acrylic acid ester-based polymerizable compound as at least a part of the polymerizable component, and curing for the epoxy resin are provided on the printed wiring board. A thermosetting solid resin layer is formed on the printed wiring board by repeatedly applying a liquid composition containing a photopolymerization initiator for the polymerizable compound and a photopolymerization initiator for the polymerizable compound by a printing method and irradiating it with active light. death.

There is provided a method for electromagnetic shielding of a printed wiring board, which is characterized in that a metal film is then laminated and adhered to the surface of the thermosetting resin layer and heat treated.

Note that the (meth)acrylic acid polymerizable compound referred to herein means an acrylic ester polymerizable compound and/or a methacrylic ester polymerizable compound.

In the present invention, as a printing ink, an epoxy resin, a polymerizable compound containing a polyfunctional (meth)acrylic acid ester polymerizable compound as at least a part of the polymerizable component, a curing agent for the epoxy resin, and a polymerizable compound for the epoxy resin are used. A thermosetting liquid composition containing a photopolymerization initiator for the compound is used.

The epoxy resin used in the present invention is not particularly limited as long as it is a polyepoxy compound having two or more epoxy groups in one molecule. Examples of such resin include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, Glycidyl ethers of polyhydric phenols such as brominated bisphenol A, phenol novolac, and talesol novolak; glycidyl ethers of polyhydric alcohols such as glycerin, butyne diol, and polypropylene glycol; phthalic acid, terephthalic acid, isophthalic acid, dimer acid, etc. In addition to glycidyl esters of carboxylic acids, glycidyl ethers of polyalkylene oxides, epoxy resins made by epoxidizing polybutadiene with peracetic acid,
Examples include heterocyclic epoxy resins.

The epoxy resin used in the present invention is preferably one that is liquid at room temperature, but is not necessarily limited to liquid. Solid epoxy resins can also be used as long as they are dissolved therein to give a liquid composition.

In the present invention, a maleimide triazine resin is preferably used as a curing agent for the epoxy resin.

Maleimide/triazine resin is an addition polymerizable thermosetting polyimide resin having a cyanate group consisting of a maleimide component and a triazine resin component. It can be obtained by carrying out a heating reaction in the absence of the compound.

In this case, the cyanate compound forms a triazine ring upon heating. In addition, as a catalyst for this reaction,
Organic metal salts, tertiary amines, etc. can be used.

As the polyfunctional maleimide compound, for example, those represented by the following general formula can be used.

In the above formula, R1 is an aromatic or alicyclic organic group having a valence of 2 or more, usually a valence of 5 or less, and preferably a divalent.

xi and xi are hydrogen, halogen or an alkyl group.

n is a number corresponding to the valence of R1, and is an integer of 1 to 5.

The polyfunctional maleimide compound represented by the general formula (1) is produced by reacting a maleic anhydride compound with a polyvalent amino compound to form maleamic acid, and then dehydrating and cyclizing the maleamide linkage according to a conventional method. can do. In this case, examples of the polyvalent amino compound include phenylene diamine, xylylene diamine, cyclohexane diamine, 4,4'-diaminobiphenyl, bis(4
-aminophenyl)methane, bis(4-aminophenyl)ether, bis(4-amino-3-methylphenyl)
Methane, 2゜2-bis(4-aminophenyl)propane, 2,2-bis(4-amino-3-methylphenyl)propane, 2,2-bis(4-amino-3-chlorophenyl)propane, 1, 1-bis(4-aminophenyl)-
Examples include 1-phenylethane.

As the polyfunctional cyanate compound, for example, those represented by the following general formula can be used.

R"(OCN)m (II) In the above formula, Rm is a divalent or pentavalent or less, preferably divalent aromatic group. Ugly is a number corresponding to the valence of R3, 2-5
is an integer.

Examples of the polyfunctional cyanate compound represented by the general formula (II) include dicyanatobenzene, tricyanatobenzene, dicyanatonaphthalene, 4,4'
-dicyanatobiphenyl, bis(4-dicyanatophenyl)methane, 2,2-bis(4-cyanatophenyl)propane, 2,2-bis(3,5-dichloro-4-
Examples thereof include cyanatophenyl)propane, bis(4-cyanatophenyl)ether, and the like.

When manufacturing maleimide triazine resin, what is the ratio of maleimide compound and cyanate compound?

By weight, maleimide compound: 10-40%, preferably 20-30%, cyanate compound = 90-60%, °
Preferably the proportion is 80 to 70%. If the maleimide compound component is less than the above range, the resulting resin will have poor heat resistance, while if it is more than the above range, the cyanate compound component (cyanate group 0C
N) is reduced, resulting in poor reactivity with the epoxy group of the epoxy resin, resulting in problems such as insufficient curability.

Maleimide triazine resin can also be used in liquid or solid form, like the epoxy resin. This maleimide triazine resin reacts with the epoxy resin as a curing agent, and ultimately provides a thermoset product with excellent moisture absorbing and insulating properties.

The polyfunctional (meth)acrylate-based polymerizable compound (hereinafter also simply referred to as a polymerizable compound) used in the present invention is a monomer having two or more (meth)acrylate groups in one molecule. Oligomers are used. As such, for example, the following can be exemplified.

1.4-Butanediol di(meth)acrylate.

1.6-hexanethiol di(meth)acrylate, (
Poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate.

Neobentyl glycol di(meth)acrylate.

Hydroxypivalic acid neopentyl glycol di(meth)acrylate.

Bis((meth)acryloxyethyl)hydroxyethyl isocyanurate, tris((meth)acryloxyethyl)isocyanurate, ethylene oxide modified bisphenol A di(meth)acrylate.

Propylene oxide modified bisphenol A di(meth)
Acrylate.

Trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, polybasic acid and polyol and (meth)acrylic acid or hydroxyalkyl (meth)acrylate ) oligoester poly(meth)acrylates by reaction with acrylates, epoxy poly(meth)acrylates by reaction of epoxy resins with (meth)acrylic acid, urethanized poly(meth)acrylates by reaction of polyisocyanates with polyols and hydroxyalkyl (meth)acrylates. (meth)acrylate etc.

Furthermore, in the composition used in the present invention, a monofunctional (meth)acrylic acid ester polymerizable compound (hereinafter also simply referred to as a reactive diluent) may be added as a reactive diluent. As such, for example, the following can be exemplified.

2-Hydroxyethyl (meth)acrylate.

2-Hydroxypropyl (meth)acrylate.

Polyethylene glycol mono(meth)acrylate Polypropylene glycol mono(meth)acrylate, Polycaprolactone mono(meth)acrylate.

Methoxyethyl (meth)acrylate.

Ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate.

Methylcarpitol (meth)acrylate.

Ethylcarpitol (meth)acrylate.

Butylcarpitol (meth)acrylate.

(Alkyl-substituted) phenoxy (poly) ethylene glycol (meth) acrylate.

(Alkyl-substituted) phenoxy (poly)propylene glycol (meth)acrylate.

Dicyclopentanyl (meth)acrylate.

Dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate.

(meth)acryloyloxyethyl monophthalate, acryloyl monophorin, etc.

As the photopolymerization initiator used in the present invention, any compound can be used as long as it generates radicals upon irradiation with actinic light such as ultraviolet rays. Examples of such substances include benzophenone, benzyl, PsP'-bis(dimethylamino)benzophenone-PsP'-bis(diethylamino)benzophenone-PsP'-dibenzoylbenzene, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether , benzyl dimethyl ketal, l-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1 -on, anthraquinone.

Acetonaphthenequinone, 2-tartbutylanthraquinone, phenanthreneanthraquinone, PeP'-bis(dimethylamino)thiobenzophenone, Primulin,
Carbazole, tomethyl-3-nitrocarbazole, xanthone, thioxanthone, chlorothioxanthone, diethylthioxanthone, diiso-propylthioxanthone, carbon tetrabromide, ω, ω.

ω-tribromomethylphenylsulfone, ω, ω.

Examples include ω-tribromomethyl phenyl ketone.

In the composition used in the present invention, the total amount of the epoxy resin, maleimide triazine resin (curing agent), polymerizable compound, and reactive diluent is 100 parts by weight, and the epoxy resin is 10 to 70 parts by weight, preferably 20 parts by weight. ~60 parts by weight, maleimide triazine resin is 1G-70 parts by weight, preferably 20-60 parts by weight 1 The total amount of polymerizable compound and reactive diluent is 5-60 parts by weight, preferably 10-50 parts by weight. The ratio of a certain 0 polymerizable compound to a reactive diluent is 1
With respect to the total amount of both, the polymerizable compound 3G-100% by weight, preferably 40-100% by weight, the reactive diluent O~
If the ratio of the total amount of the polymerizable compound and the reactive diluent is less than the above range, the thermosetting solid resin layer (B stage resin)
On the other hand, if the amount exceeds the above range, there are problems such as deterioration of the hygroscopic insulation properties of the cured resin.

The ratio of photopolymerization initiator used is generally epoxy resin,
The proportion is 0.1 to 10 weight S, preferably 1 to 6 weight S, based on the total amount of maleimide triazine resin, polymerizable compound and reactive diluent.

As the curing agent used in the present invention, it is preferable to use the maleimide triazine resin described above.

Hardeners conventionally known for epoxy resins can be used in place of or in conjunction with maleimide triazine resins. In this case, any curing agent can be used as long as it shows no substantial reactivity with the epoxy resin at room temperature or low temperature (latent curing agent). Examples of such substances include aromatic amines such as diaminodiphenylsulfone, acid anhydrides such as methylnadic anhydride and methyltetrahydrophthalic anhydride, boron trifluoride complexes, organometallic compounds, phenolic compounds, and novolak-type compounds. In addition to phenol resins, preferred examples of nitrogen-containing latent curing agents include dicyandiamide, guanamines such as acetoguanamine and benzoguanamine, adipic acid dihydrazide, hydrazides such as stearic acid dihydrazide, isophthalic acid dihydrazide, cepatic acid dihydrazide, 2,4-dihydrazide-6-
Examples include triazine compounds such as methylamino-8-triazine, imidazole and imidazole derivatives, or modified products thereof.

The latent curing agent is preferably used together with a curing accelerator.As such curing accelerator, it is preferable to use the following.

(1) Amine adduct curing accelerator Examples of the curing accelerator include (i) 2,3-bis(4-(2,3-epoxypropoxy)phenyl)propane or 1,3-bis(4-( 4-(2,3-epoxypropoxy)-α,α-dimethylbenzyl]phenoxy)-2-propatool, (…) condensate of phenol, formaldehyde, and dimethylamine, (positive) 2-alkyl (1 carbon number -3) an adduct of imidazole or 2-alkyl (1 to 3 carbon atoms)-4-methylimidazole and 2,3-epoxypropyl-phenyl ether and (iv
) The use of polyadducts of piperazine is preferred.

(2) Solid solution of 1,8-diaza-bicyclo(5,4,0) undecene and phenol novolac. This solid solution consists of 1,8-diaza-bicyclo(5,4,0)
) It can be obtained by mixing and heating undecene-7 and phenol novolak to react, cooling the mixture, solidifying it, and pulverizing it. Phenol novolac means a condensate of phenols and aldehydes. Phenols include monohydric phenols such as phenol, alkyl or alkoxyphenols, halogenated phenols, and polyhydric phenols such as resorcinol or bisphenol A.

Preferred phenols are phenol, P-tert-butylphenol and bisphenol A. Examples of aldehydes include furfuraldehyde, chloral, acetaldehyde, and preferably formaldehyde. l,
The solid solution of 8-diazo-bicyclo(5,4,0)undecene-7 and phenol novolak may include not only a complete salt form but also a simple solid solution. The content of diazo-bicyclo(5,4,0)undecene-7 in the solid solution is preferably 10 to 50% by weight, and does not necessarily have to be a stoichiometric amount.

(3) Other urea derivatives such as 3-(3,4-dichlorophenyl)-1,1-dimethylurea, imidazole and its derivatives.

Or modified products thereof can also be used. These curing accelerators are appropriately selected in relation to the latent curing agent.

If necessary, a polymer, an inorganic filler, and an inorganic thixotropic agent (thixotropic agent) can be further added to the composition used in the present invention. These things are.

Although it can be blended into the composition as it is without surface treatment, considering the physical properties of the cured product, it is preferable to perform surface treatment with a silane coupling agent before use.As the silane coupling agent, epoxysilane, aminosilane, etc. etc. are preferably used.

Furthermore, considering the storage stability of the composition, it is preferable to use it after surface treatment with a siloxane compound. In this case, the siloxane compound refers to a compound having a siloxane bond (Si-0 bond) in the molecule. For example, the following compounds can be used.

In the formula, R is a monovalent hydrocarbon group, for example methyl.

Examples include ethyl, propyl, vinyl, phenyl and the like.

lI is a positive integer.

In the formula, R has the same meaning as above. ■ is one ■, -0H
1-〇R1, -R"-CH-CH,, -R"-N) 11
．． -R"-COOH1ゝ0'-R"-OH,etc.; in this case, R1 is a monovalent hydrocarbon group, R2 is a divalent hydrocarbon group, and aliphatic and aromatic 5 lines that contain items indicate positive integers.

In the formula, R, Y and n have the same meanings as above.

In the formula, R, Y and n have the same meanings as above.

In addition, the substituent V described above may be bonded either in the face of one molecule or at the end of the molecular chain.

The viscosity (at 25°C) of the siloxane compound depends on its type, but - for boat fishing, it is preferably 10,000 centistokes or less. 0.1 to loo parts by weight
The proportion is 10 parts by weight, preferably 0.5 to 5 parts by weight.

Specific examples of the inorganic filler include crystalline silica 11-fused silica, alumina, aluminum hydroxide, calcium carbonate, talc, clay, calcium silicate, glass flakes, spherical glass, and various whiskers.

Examples of non-thixotropic agents include ultrafine silica and alumina with an average particle size of IO0 nm or less, aluminum hydroxide with an average particle size of 31s or less, fibrous magnesium oxysulfate, powdered asbestos, and fibrous Silica, fibrous potassium titanate.

Examples include scaly mica and a montmorillonite-organic base complex called bentonite.

Various auxiliary ingredients can be further added to the composition used in the present invention depending on its intended use. Examples of such auxiliary components include organic solvents, dyes and pigments, flame retardants, polymerization inhibitors, and antifoaming agents.

Examples include leveling agents.

In order to form a thermosetting solid resin layer on a predetermined substrate surface according to the present invention, the liquid composition is used as a printing ink and applied to the substrate surface by a printing method. in this case,
As a printing method, a screen printing method is generally used. In addition to the printing method, coating methods such as a roll coater method and a curtain coater method can also be used.6 Next, the coated surface is irradiated with actinic light. By this irradiation with actinic light, the (meth)acrylic acid ester polymerizable compound in the composition forming the coating layer is polymerized by the action of the photopolymerization initiator and has a high molecular weight, and as a result, the coating layer becomes solid. (B-staged), thermosetting solid resin (B-stage resin) layer (hereinafter also simply referred to as solid resin layer) As the active light 1, ultraviolet rays are usually used, but other active rays 1, such as electron A beam, laser light, etc. may also be used.

Next, on the surface of the solid resin layer formed in this way,
After applying the liquid composition again by the printing method in the same manner as above, it is irradiated with actinic rays to polymerize the (meth)acrylic acid ester-based polymerizable compound in the composition that forms the coating layer, thereby increasing the molecular weight. let In this way, a pinhole-free solid resin layer is formed on the substrate surface. If necessary.

Each of the above steps can also be repeated one or more times.

When forming a solid resin layer on the substrate surface as described above, the thickness of the coating layer formed by one printing application is as follows:
Usually 5-300. , preferably 10-20G, and the speed of the final solid resin layer is 10-20G.
6004. Preferably it is 20-400.

Further, the surface of the solid resin layer is preferably dry to the touch so that the composition can be easily applied by the next printing method.

The thermosetting solid resin layer formed on the surface of the substrate as described above can be heat-treated to make it an insulating layer, or a metal film such as copper foil can be laminated on the surface of the solid resin layer. A metal film can also be attached by pressure bonding and then heat treatment. Further, two substrates each having a thermosetting solid resin layer on one surface can be laminated and pressed together so that the solid resin layers are in contact with each other, and the substrates can be bonded together by heat treatment.

By using the method for forming a thermosetting solid resin layer according to the present invention, printed wiring boards can be industrially advantageously electromagnetically shielded. That is, first, a solid resin layer is formed on the printed wiring board as described above, and then heat treated to form a cured resin layer, and a conductive layer is formed on this cured resin layer.

In this case, the conductive layer can be formed by conventionally known methods, such as applying a conductive paint such as silver paint or copper paint, or laminating and bonding metal foil such as copper foil. Can be mentioned. When forming a conductive layer, it is preferable to uniformly polish the surface of the cured resin layer.

According to another advantageous electromagnetic shielding method for a printed wiring board according to the present invention, a solid resin layer is first formed on the printed wiring board as described above, and a metal such as copper foil is placed on the solid resin layer. After laminating and crimping the foil.

Heat treatment. In this way, a conductive layer can be easily formed on a printed wiring board with an insulating layer interposed therebetween.

The conductive layer formed on the printed wiring board can be grounded by extending a portion of the conductive layer to the ground terminal portion of the board and bringing it into contact with the terminal. Also, after forming the conductive layer, if necessary.

A predetermined process such as forming a through hole at a predetermined location by drilling can be performed.

(Effect of the invention) In the present invention, the thermosetting liquid composition used as the printing ink has good stability at room temperature, but when irradiated with actinic rays, the polymerizable compound undergoes a polymerization reaction, resulting in a high molecular weight to easily form a solid resin (B-stage resin) that exhibits a semi-solid to solid state as a whole. and,
This solid resin contains an unreacted epoxy resin and a curing agent, and has thermosetting properties. By heating this solid resin to a high temperature, the epoxy resin and the curing agent react and are converted into a cured resin. This cured resin is insoluble and infusible, and has excellent heat resistance, chemical resistance, and insulation properties. When a maleimide triazine resin is used as the curing agent, a cured resin with excellent moisture absorption and insulation properties can be obtained.

Since the method for forming a thermosetting solid resin layer and the method for forming a cured resin layer on the surface of a substrate according to the present invention include the step of printing and applying a liquid composition multiple times, the resulting solid resin layer and its cured resin layer is of good quality with no pinholes. When pinholes occur in the insulating layer.

However, in the case of the present invention, such a problem does not occur.Moreover, in the case of the present invention, the solidification of the coating layer made of the liquid composition applied to the surface of the substrate is prevented. Since it is based on a radical polymerization reaction of a polymerizable compound using actinic light, it can be completed in a very short time of 5 to 60 seconds, so it is very efficient. Furthermore, unlike when polymerization reactions are carried out by heating, when polymerization reactions are carried out using actinic rays, an increase in the temperature of the coating layer is avoided, and the reaction between the epoxy resin and the curing agent can be substantially completely suppressed. , a uniform thermosetting solid resin layer can be stably obtained with good reproducibility.

The method for forming a solid resin layer and a cured resin layer according to the present invention includes:
In order to obtain a multilayer wiring board, it can be advantageously used as a method for laminating and adhering an outer layer printed wiring board to an inner layer printed wiring. It can also be used as a bonding method for bonding electrical/electronic components to a substrate.

As described above, the electromagnetic shielding method for a printed wiring board according to the present invention includes the step of efficiently forming a pinhole-free curable solid resin layer on the board, so it is more industrially efficient than conventional methods. It can be carried out advantageously.

The method of forming a thermosetting solid resin layer on the surface of a substrate according to the present invention is advantageously applied to forming an insulating layer on electrical/electronic components such as printed wiring boards.

Although not necessarily limited to these, methods and methods are available for forming pinhole-free thick insulating layers on various conductive solid surfaces, including various metal surfaces such as copper, iron, and aluminum. It can be applied as a method of bonding various solid surfaces together.

(Example) Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A liquid composition having the component composition shown in Table 1 below was screen printed on a printed wiring board using a 200 mesh screen, and while the printed matter was transferred at a speed of 4 oboro/min, a high pressure mercury lamp of 80 W was used. After light irradiation using two /c Peng lamps, the printing process and light irradiation process were repeated again to obtain a printed wiring board having a solid resin (B stage resin) layer on the surface.

Next, this printed wiring board was placed in a heating chamber at a temperature of 150° C. for 1 hour to cure the B-stage resin layer.

Next, a conductive paint (copper paste) was applied and cured on the surface of this cured resin layer to form an electromagnetic shielding layer.

Table 1 Example 2 A printed wiring board having an electromagnetic shielding layer was obtained in the same manner as in Example 1 except that a liquid composition having the composition shown in Table 2 below was used.

Table 2 Example 3 The liquid composition shown in Table 3 below was applied to one side of a printed wiring board for 70 minutes.
Screen printed using a mesh screen.

While transporting the printed matter at a speed of 3 to 7 minutes, it was irradiated with light using two high-pressure mercury lamps of 80 W/Cm to form a B-stage resin layer, and then the printing process and light irradiation process were repeated again.

Next, a copper foil with a thickness of 18 pa was placed on the B-stage resin layer of the printed wiring board having the B-stage resin layer obtained as described above, and after thermal lamination at a temperature of 120°C, lamination was performed at a temperature of 150°C. The B-stage resin was left in a heating chamber for 1 hour to cure and form an electromagnetic shielding layer.

Table 3 Reference Example A thermosetting liquid composition having the component composition shown in Table 4 below was prepared.

Next, among the compositions obtained in this way, the compositions shown in Experimental Areas 1 to 3 were coated on IPC-825 comb-shaped electrodes by screen printing using a 200 mesh screen. The coating process and ultraviolet wrap irradiation process were repeated three times to obtain a comb-shaped electrode having a solid resin (B-stage resin) layer on the surface.

Next, the comb-shaped electrode having the B-stage resin layer obtained as described above was placed in a heating chamber at a temperature of 150°C for 1 hour.
The stage resin layer was cured. Using each electrode obtained in this way as a test piece, the resistance value when 500V is applied between the bottles of the test piece is measured immediately after curing (initial value)
At the same time, the samples were also measured after 2 hours of boiling.

The measurement results are shown in Table 4.

Table 3 As can be seen from the above reference examples, the composition used in the present invention can be easily converted into a solid resin (B stage), and
Thermosetting of the stage resin is also easy, and the resulting thermosetting resin exhibits excellent hygroscopic insulation properties.

The specific contents of the components shown in Tables 1 to 3 are as follows.

Epicoat 828...Bisphenol A type epoxy resin, epoxy equivalent 184-194 (manufactured by Yuka Shell Epoxy ■) Epicoat 1001...Bisphenol A type epoxy resin, epoxy equivalent 450-500 (Yuka Shell Epoxy ■11) BT- 2100...Bismaleimide triazine resin (Mitsubishi Gas Chemical [11) MANDA...Hydroxypivalic acid neopentyl glycol diacrylate TMPTA...Trimethylolpropane triacrylate Aerosil #200...Ultrafine powder synthetic silica (manufactured by Nippon Aeroseal ■) Photopolymerization initiator: l-hydroxycyclohexyl phenyl ketone

Claims (7)

[Claims] (1) Epoxy resin, polyfunctional (meth) on the substrate surface
Applying a liquid composition containing a polymerizable compound containing an acrylic ester polymerizable compound as at least a part of the polymerizable component, a curing agent for the epoxy resin, and a photopolymerization initiator for the polymerizable compound by a printing method, A method for forming a thermosetting solid resin layer on a substrate surface, the method comprising repeatedly performing the step of irradiating actinic rays. (2) The method of claim 1, wherein the curing agent is a maleimide triazine resin. (3) The method of claim 1, wherein the substrate is a printed wiring board. (4) A method for forming a cured resin layer on the surface of a substrate, which comprises forming a thermosetting solid resin layer on the surface of the substrate by the method according to claim 1, and then performing a heat treatment. (5) Epoxy resin, polyfunctional (
A liquid composition containing a polymerizable compound containing a meth)acrylic acid ester polymerizable compound as at least a part of the polymerizable component, a curing agent for the epoxy resin, and a photopolymerization initiator for the polymerizable compound is applied by a printing method. and forming a thermosetting solid resin layer on the printed wiring board by repeatedly performing the step of irradiating with actinic rays, and then performing a heat treatment to turn the thermosetting solid resin layer into a cured resin layer, A method for electromagnetically shielding a printed wiring board, comprising forming a conductive layer on the surface of the cured resin layer. (6) Epoxy resin, polyfunctional (
A liquid composition containing a polymerizable compound containing a meth)acrylic acid ester polymerizable compound as at least a part of the polymerizable component, a curing agent for the epoxy resin, and a photopolymerization initiator for the polymerizable compound is applied by a printing method. A thermosetting solid resin layer is formed on the printed wiring board by repeating the step of irradiating with actinic rays, and then a metal film is laminated and adhered to the surface of the thermosetting resin layer, followed by heat treatment. A method for electromagnetic shielding of a printed wiring board, characterized by: (7) The method according to claim 6 or 7, wherein the curing agent is a maleimide triazine resin.