JP2003034885A - Method for manufacturing mesh of metal foil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a mesh of a simple substance metal foil, having superior usability, optical transparency, and an electromagnetic wave shielding property, in a simple process. SOLUTION: This method for manufacturing the mesh of the simple substance metal foil comprises forming a photoresist layer 1 on both surfaces of the metal foil 4, laminating a transparent support 5 on one surface of the photoresist layer 1, then, exposing the photoresist layer 1 laminated with no transparent support 5 to form a predetermined mesh pattern, exposing the whole photoresist layer 1 laminated with the transparent support 5 to form a developed resist part 7, then, removing an undeveloped part 8 of the photoresist layer 1, etching the part of the metal foil 4 corresponding to the removed part, and simultaneously removing the developed resist parts 7 on both surfaces of the metal foil 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a metal foil mesh using a photoresist method, and a metal foil mesh applied to an electromagnetic wave shielding material, especially a metal foil mesh suitable as an electromagnetic wave shielding material for a display. To a method of manufacturing.

[0002]

2. Description of the Related Art In recent years, an electromagnetic wave shield material has been attracting attention as one of means for blocking an electromagnetic wave emitted from an electronic device. As the electromagnetic wave shielding material, there is known one using a so-called wire mesh, which is a metal mesh woven of metal wires typified by a sieve for fine particle classification, as a metal mesh. Further, for example, an electromagnetic wave shielding material using a resin mesh such as polyester as a base material and using a metal mesh obtained by coating the base material with a metal such as copper or nickel by means such as electroless plating is also known.

Some of these electromagnetic wave shield materials are applied to displays such as plasma displays. In that case, it is required to be as thin as possible, and it is necessary to achieve a good balance between the light transmission property and the electromagnetic wave shielding property which is contrary to the light transmission property. -35
There is a metal foil mesh disclosed in No. 0168.

Further, Japanese Patent Application No. 2001-076183 discloses a method for producing the above metal foil mesh as a single body. As the manufacturing method, first, a photoresist layer is formed on both sides of a metal foil, a predetermined mesh pattern is exposed on one photoresist layer using a mask, and the entire surface of the other photoresist layer is exposed and developed. A resist portion is formed. Then, the undeveloped portion of the photoresist layer is removed, the metal foil corresponding to the removed portion is etched, and then the developed resist portions on both sides of the metal foil are removed at the same time to manufacture a single metal foil mesh.

[0005]

However, in the conventional method for producing a metal foil mesh described above, when the metal foil is very thin and a negative photoresist layer is used, the layer strength of the laminate is very high. It was low, difficult to handle, and had a problem in workability in each step of the above manufacturing method.

Therefore, the present invention provides a method for producing a metal foil mesh by further providing a transparent support on the photoresist layer on which the mesh pattern is not formed in the laminate in which the photoresist layer is laminated on the metal foil. It is an object of the present invention to provide a method capable of producing a single metal foil mesh having excellent light transmittance and electromagnetic wave shielding property in each step, which has excellent workability and simple steps.

[0007]

The method for producing a metal mesh according to the present invention comprises a step of forming a photoresist layer on both sides of a metal foil, and a step of laminating a transparent support on one side of the photoresist layer. The step of exposing a predetermined mesh pattern to the photoresist layer not provided with the transparent support and exposing the entire surface of the photoresist layer provided with the transparent support to form a development resist portion, and the undeveloped portion of the photoresist layer The method is characterized by including a step of removing and etching the metal foil corresponding to the removed portion, and a step of removing the developing resist portion.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, more preferred embodiments of the present invention will be described in detail with reference to the drawings. In the method for producing the metal foil mesh of the present invention, first, photoresist layers are formed on both sides of the metal foil. As a method of forming a photoresist layer on both sides of the metal foil, a liquid photoresist may be applied and formed on the metal foil by a roll coater method, a dipping method, a spray method, a spinner method, or the like, but a dry film resist is used. It is preferably formed by using. As a dry film resist, generally, as shown in FIG.
Polyethylene (PE) film 2 and polyethylene terephthalate (P
ET) film 3 is used in each layer. The thickness of this PET film is 12.5 to 15 μm, which is suitable for pattern exposure by the photoresist method.

The method for producing the metal foil mesh of the present invention using this dry film resist will be specifically described below.
First, in the step of forming the photoresist layer on the metal foil,
As shown in FIG. 2A, the PE film 2 of the dry film resist is peeled off and the metal foil 4 is formed by using a pair of rollers.
It is preferable to form the photoresist layer 1 on both surfaces of the metal foil 4 at the same time by sticking two dry film resists while applying pressure to both surfaces so as to sandwich the film.

Then, as shown in FIG. 2B, a transparent support 5 is attached to the surface of the PET film 3 on one photoresist layer 1 via an adhesive to improve the layer strength of the laminate. Let This facilitates handling of the laminate in the subsequent steps such as exposure / development of the photoresist layer and etching of the metal foil, and excellent workability can be obtained. In the method for manufacturing a metal foil mesh of the present invention, one side of the photoresist layer 1 formed on the metal foil 4 is exposed on the entire surface and acts as a part of the protective layer at the time of etching. Even if the transparent support 5 is further laminated, no problem will occur in the subsequent steps.

Next, after a mask 6 on which a predetermined mesh pattern is printed as a light transmitting portion is laminated on the surface of the PET film 3 on the photoresist layer 1 on which the transparent support 5 is not provided, the mask 6 is placed on the mask 6. Irradiate ultraviolet rays. As a result, as shown in FIG. 2C, the photoresist layer 1 in the portion corresponding to the light transmitting portion of the mask 6 is exposed, and the exposed portion becomes the developing resist portion 7 and is formed on the metal foil 4. The unexposed portion remains as the undeveloped portion 8.

On the other hand, in the photoresist layer 1 provided with the transparent support 5, the entire surface of the photoresist layer 1 is exposed as shown in FIG.
The development resist portion 7 whose entire surface is cured is formed. The exposure of these photoresist layers 1 may be performed on each side or both sides. For the above exposure, the mask 6
Instead of the above-mentioned lamination and irradiation with ultraviolet rays or the like, means for directly irradiating the photoresist layer 1 with laser light may be used.

The photoresist layer 1 may be either a negative type which is cured by ultraviolet rays or the like or a positive type which is decomposed by ultraviolet rays or the like. In this case, the mesh pattern of the mask 6 is used in each case. A light-transmissive or non-transmissive material is appropriately used. Further, when the photoresist layer 1 on which the mesh pattern is not formed is a positive type, it is not exposed to light and is used as a developing resist portion. Further, the photoresist layer 1 formed on both sides of the metal foil 4 may be another type of photoresist, but the metal foil 4 described later is used.
The same type of photoresist is preferable because the developing resist portions 7 formed on both surfaces of the can be removed at the same time.

Next, after removing the mask 6 and further peeling off the PET film 3, the undeveloped portion 8 of the photoresist layer 1 is removed by immersing in a treatment liquid for resist removal, for example, a sodium carbonate aqueous solution. As a result, as shown in FIG. 2D, only the development resist portion 7 formed in a mesh pattern on one surface is formed on the surface of the metal foil 4, and the development resist portion 7 is formed on the other surface. , PE on it
Together with the T film 3 and the transparent support 5, it serves as a protective film for protecting the metal foil 4 from an etching solution or the like in the etching process. Then, as shown in FIG.
By etching means such as chemical etching in which the whole is immersed in an etching treatment liquid, for example, a ferric chloride hydrochloric acid solution,
Etching the metal foil 4 in the portion corresponding to the undeveloped area 8,
After that, the development resist portion 7 on both sides of the remaining metal foil 4
2 is immersed in a resist removing treatment solution such as a caustic soda diluting solution and removed at once or separately.
A single metal foil mesh as shown in (f) can be obtained.

When the metal foil mesh obtained according to the present invention is used as an electromagnetic wave shield material for a display,
In order to improve the visibility, it is preferable that the front surface side of the shield material (the viewing surface side of the display) is black. As a method of blackening the metal foil mesh, a method of subjecting the metal foil to a black oxidation treatment in advance or after removing the developing resist portion, and performing a metal plating with a particle diameter controlled on the metal foil surface in advance, It is possible to use a method of blackening, a method of blackening an unmetallized portion by heating and oxidizing the etched metal foil mesh after removing the developing resist portion. In addition, the blackened area of the metal foil mesh is
It can be arbitrarily controlled by the use of a mask and the presence or absence of metal plating.

Further, the mesh pattern of the metal foil mesh obtained by the present invention can be freely controlled in the developing step by the photoresist method, and when used as an electromagnetic wave shielding material for a display, it has a light transmitting property and an electromagnetic wave shielding property. In order to achieve compatibility with both properties, it is preferable that the width of the line portion of the mesh pattern is 10 to 50 μm, preferably 15 to 30 μm, and the aperture ratio is 80% or more, preferably 85% or more. The opening ratio mentioned here means the total area of the holes with respect to the effective area of use of the metal foil. The width of the holes in the mesh pattern (the pitch of the line parts) is 100 to
500 μm is suitable, and preferably 150 to 300 μm.
m.

Further, the mesh pattern is preferably a geometric pattern, and the shape of the holes is appropriately selected from parallelograms such as squares and rectangles, circles or regular hexagons (honeycomb shape). Further, since it is essential that any part has a certain characteristic (mainly light transmitting property and electromagnetic wave shielding property), it is preferable that the parts are regularly arranged.

As the material of the metal foil used in the present invention,
Metals such as copper, iron, nickel, aluminum, gold, silver and platinum, alloys of two or more kinds of these metals (for example, copper-nickel alloy, stainless steel, etc.), and metal compounds capable of forming a foil. A system material is used. Among these metals, particularly preferable are alloys or metal compounds of copper, aluminum, iron, nickel, and those that can be easily foil-formed by rolling, electrolysis, or the like, because they can be manufactured at low cost. The thickness is preferably as thin as possible, and is 5 to 50 μm, preferably 8 to 40 μm, and more preferably 10 to 25 μm.

As the photoresist layer used in the present invention, various conventionally known photoresists can be used, but a photopolymerization type photosensitive resin is preferable, and specifically, a photopolymerization monomer and a binder resin are preferable. A commonly used photocurable composition containing a photopolymerization initiator and other auxiliaries is preferably used. In the method for producing a metal foil mesh of the present invention, an alkaline water developing type dry film resist is particularly suitable.

Examples of the photopolymerizable monomer include ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth). ) Acrylate, 1,6-hexanediol di (meth) acrylate, 2,2-bis [4- (meth) acryloxyproproxyphenyl] propane, trimethylolpropane tri (meth) acrylate, pentaerythritol penta (meth) Acrylate, tri (meth)
Acryloxyethyl phosphate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, pentaerythritol penta (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, glycerin triglycidyl ether tri (meth) acrylate, etc. These may be used alone or in admixture of two or more.

Examples of the binder resin include vinyl copolymers, polyesters, and epoxy resins, which are usually used alone or in combination of two or more. Examples of the monomer component used in the vinyl-based copolymer include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, (meth)
Propyl acrylate, butyl (meth) acrylate, 2-
Examples thereof include hydroxyethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, methoxyethyl (meth) acrylate, styrene, (meth) acrylamide, (meth) acrylonitrile and vinyl acetate, and these monomers are usually alone. Or a mixture of two or more kinds.

The polyester is (anhydrous) phthalic acid,
Isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, (anhydrous) maleic acid, fumaric acid, adipic acid, trimellitic anhydride, pyromellitic anhydride and other divalent or higher carboxylic acids and ethylene glycol, propylene glycol, 1,3- Butanediol, diethylene glycol,
It can be obtained by an esterification reaction with a divalent or higher alcohol such as dipropylene glycol, triethylene glycol, neopentyl glycol, hydrogenated bisphenol A, glycerin or trimethylolpropane.

Examples of the epoxy resin include bisphenol epoxy resin and novolac epoxy resin, which are obtained by adding a monovalent carboxylic acid such as acetic acid, oxalic acid or (meth) acrylic acid. May be.

In the present invention, a photopolymerizable monomer,
The compounding ratio (weight ratio) with the binder resin is from 10/90 to
It is preferably adjusted to 70/30, particularly 30/70 to 50/50.

Examples of the photopolymerization initiator include benzophenone, Michler's ketone, 4,4'-bis (diethylamino) benzophenone, t-butylanthraquinone,
2-Ethylanthraquinone, thioxanthones, benzoin alkyl ethers, benzyl ketals and the like can be mentioned, and these can be used alone or as a mixture. The photopolymerization initiator is usually added in an amount of 0.
It is preferable that the content is 01 to 30 wt%.

The photoresist may contain a sensitizer, a dye, a color pigment, an adhesion improver, a polymerization inhibitor, a coating surface improver, a plasticizer, etc., if necessary.
Examples of commercially available photoresists include Alfo NIT series manufactured by Nippon Synthetic Chemical Industry Co., Ltd., PMER series manufactured by Sankyo Kasei Co., Ltd., and Liston series manufactured by DuPont Japan.

The transparent support used in the present invention has no adverse effect on the exposure of the photoresist layer, and is resistant to the processing solution for removing the undeveloped resist and the etching solution for the metal foil. Any material may be used as long as it is a polypropylene (PP) film or a PET film.

[0028]

As described above, according to the method for producing a metal foil mesh of the present invention, the metal foil is very thin, and the layer strength is improved even in a laminate using a negative photoresist layer. By improving the workability in each step of the manufacturing method of the metal foil mesh, and in a simple process,
It is possible to produce a single metal foil mesh having both excellent light transmission and electromagnetic wave shielding properties.

Particularly in the present invention, the transparent support is provided to improve the layer strength of the laminate, that is, to strengthen the stiffness of the laminate, thereby preventing the laminate from waviness in the etching process. Therefore, it is possible to solve the problem that the metal foil is deformed and etched due to the corrugated laminate in the related art, and a metal foil mesh having a good shape can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view conceptually showing a dry film resist used in the present invention.

FIG. 2 is a sectional view conceptually showing a method for manufacturing a metal foil mesh of the present invention.

[Explanation of symbols]

1 ... Photoresist layer, 2 ... PE film, 3 ... PET
Film, 4 ... Metal foil, 5 ... Transparent support, 6 ... Mask,
7 ... Developing resist portion, 8 ... Undeveloped portion.

Claims (4)

[Claims] 1. A step of forming a photoresist layer on both surfaces of a metal foil, a step of laminating a transparent support on one surface of the photoresist layer, and a predetermined step for the photoresist layer not provided with the transparent support. And exposing the entire surface of the photoresist layer provided with the transparent support to form a development resist portion, and removing an undeveloped portion of the photoresist layer to correspond to the removed portion. A method for producing a metal foil mesh, comprising: a step of etching a metal foil; and a step of removing the developing resist portion. 2. The method for producing a metal foil mesh according to claim 1, wherein the transparent support is a polypropylene film. 3. The method for producing a metal foil mesh according to claim 1, wherein the transparent support is a polyethylene terephthalate film. 4. The metal foil is made of any one of copper, iron, nickel, aluminum, gold, silver, platinum, or an alloy or metal compound of two or more of these, and has a thickness of 5 to 50 μm. The method for producing a metal foil mesh according to any one of claims 1 to 3, characterized in that: