JP2008263051A - Electromagnetic wave shield sheet and filter for pdp using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic wave shield sheet of which a fine mesh pitch and high picture quality are available at mesh formation process, in manufacturing a filter for PDP, with less damage at the process. <P>SOLUTION: An easy adhesion laminate thermoplastic resin film is characterized in that a laminate film whose main components are melamine cross-linking agent (C) and two kinds of polyester resins having different glass transition temperature, with surface energy being 48-55 mN/m, is provided on the substrate surface where a mesh is provided. The glass transition temperature of polyester resin (A) having high glass transition temperature is 110°C or higher and that of polyester resin (B) having low glass transition temperature is 60°C to less than 110°C. The melamine cross-linking agent (C) is 75-200 parts by weight relative to 100 parts by weight in total of two kinds of polyester resin. After a metal layer is formed on the surface of the same, the metal layer is made into a mesh structure using laser ablation or micro lithography method. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transparent light-transmitting electromagnetic wave shielding member used for an image display portion such as a plasma display panel (PDP) and a cathode ray tube (CRT), which are electrical products that generate electromagnetic waves, a method for manufacturing the same, and a method for producing the same It relates to the filter and display used.

  In recent years, electromagnetic waves generated from electrical products have become stricter due to radio wave interference on various precision instruments, instruments, and digital devices and the effects on human bodies. For this reason, it has been legally regulated with respect to electromagnetic wave emission, for example, regulation by VCCI (Voluntary Control Council for Interference by data processing equipment electronic office machine). In a PDP that emits electromagnetic waves, such as PDP and CRT that generate electromagnetic waves, the image display portion has other functions such as anti-reflection and near-infrared shielding in the image display portion. Attached directly to the PDP as a front filter in combination with the sheet, or attached to a transparent substrate such as glass or plastic for the front filter, and placed on the front of the PDP to shield it so that it can comply with electromagnetic wave regulations.

  As one method for producing this light-transmitting electromagnetic wave shielding sheet, there is a method of providing a metal layer having a patterned shape on a transparent substrate. As this method, a method of forming a pattern after providing a metal layer having a thickness capable of exhibiting sufficient electromagnetic shielding performance (see Patent Document 1), and a sufficient electromagnetic shielding performance after forming a pattern with a thin metal layer. There is a method of providing a metal layer up to a thickness that can be exhibited. The latter has the advantage of saving resources because less metal is removed than the former. As this latter method, for example, a method is proposed in which a pattern of a conductive material is formed by printing by screen printing, and a metal layer having a predetermined thickness is provided by plating (see Patent Document 2). The electromagnetic wave shielding sheet used for the PDP has a bright screen and does not cause the moire fringe defect. Therefore, it is preferable that the line width of the pattern is narrow and the interval between the lines is fine. However, in the case of an electromagnetic wave shield sheet used for PDP, a certain light transmittance is required due to its properties. Therefore, the finer the interval between the pattern lines, the more the line width of the pattern needs to be reduced.

  In addition, in the electromagnetic wave shielding sheet used for PDP, the aperture ratio is preferably 80% or more, and more preferably 90% or more. When producing a tetragonal mesh having an open efficiency of 90%, the relationship between the mesh spacing and the line width is 10 μm or less when the spacing is 200 μm, and similarly 8 μm or less when the spacing is 150 μm. In the case of 100 μm, it is necessary to make it 5 μm or less.

However, it is difficult for the method described in Patent Document 1 to leave such a fine line width. This is because when the etching method is used, the etching rate between the mesh intersections and the mesh intersections is different, and the thickness of the copper foil used for etching is as thick as about 10 μm, so that etching is performed to the lower part of the mask pattern formed on the copper foil. This is because it is difficult to control the effect of the so-called side etching that proceeds. In addition, since the method described in Patent Document 2 uses a printing method, it is difficult to form a fine line width of 20 μm or less on the substrate.
Japanese Patent No. 3366682 JP 2002-38095 A

  An object of the present invention is to provide an electromagnetic wave shielding sheet having a mesh-shaped metal layer, in which the line width of the mesh of the metal layer is made fine, thereby reducing image quality deterioration such as moire.

The present invention adopts the following means in view of the above-described state of the prior art. That is,
(1) On at least one side of the thermoplastic resin film,
Surface energy is 48-, comprising a polyester resin (A) having a glass transition temperature of 110 ° C. or higher, a polyester resin (B) having a glass transition temperature of 60 ° C. or higher and lower than 110 ° C., and a melamine crosslinking agent (C). Having a laminated film of 55 mN / m,
And this laminated film is 75-200 weight part of melamine type crosslinking agents (C) with respect to a total of 100 weight part of polyester resin (A) and polyester resin (B),
An electromagnetic wave shielding sheet comprising a metal layer having a mesh shape on the surface of the laminated film.
(2) The electromagnetic wave shielding sheet according to (1), wherein the polyester resin (A) and / or the polyester resin (B) is a polyester resin containing a sulfonate group.
(3) The laminated film comprises 100 to 150 parts by weight of the melamine-based crosslinking agent (C) with respect to 100 parts by weight of the total of the polyester resin (A) and the polyester resin (B). The electromagnetic wave shielding sheet as described in (1) or (2).
(4) The metal layer is formed by any one of a vacuum deposition method, a chemical reaction deposition method, or a sputtering method, and the thickness of the metal layer is 2 to 0.005 μm, The electromagnetic wave shielding sheet according to any one of 3).
(5) The electromagnetic wave shielding sheet according to any one of (1) to (4), wherein the mesh is formed by a lithography method or a laser ablation method.
(6) The electromagnetic wave shielding sheet according to any one of (1) to (5), wherein the mesh line interval is 100 to 200 μm and the mesh opening ratio is 80% or more.
(7) A filter for PDP using the electromagnetic wave shielding sheet according to any one of (1) to (6).

  According to the present invention, in the electromagnetic wave shielding sheet having a mesh-shaped metal layer, the line width of the mesh of the metal layer can be reduced. In particular, even when a so-called laser ablation method is used in which patterning is performed by irradiating a metal layer with a laser, a fine line width of 10 μm or less can be obtained. Even when the microlithography method is used, the metal layer is thinner than the conventional method, so that a finer line width can be obtained. Further, according to the electromagnetic wave shielding sheet of the present invention, since the adhesion between the metal layer and the laminated film is excellent, even when a metal layer having a fine line width of 10 μm or less is formed, the peeling of the metal layer mesh is suppressed. can do. And since the electromagnetic wave shielding sheet of this invention can refine | miniaturize the line | wire width of the mesh of a metal layer, it can be set as the high quality electromagnetic shielding sheet with little image quality degradation, such as a moire. Therefore, the electromagnetic wave shielding sheet of the present invention can be preferably used as a PDP filter.

  The thermoplastic resin film used for the electromagnetic wave shielding sheet of the present invention is a general term for films that are melted or softened by heat, and is not particularly limited. Typical examples include polyester films, polypropylene films, and polyethylene. Polyolefin film such as film, polylactic acid film, polycarbonate film, acrylic film such as polymethyl methacrylate film and polystyrene film, polyamide film such as nylon, polyvinyl chloride film, polyurethane film, fluorine film, polyphenylene sulfide film, etc. be able to.

  The thermoplastic resin film used in the present invention is desirably excellent in transparency, and preferably has a total light transmittance of 80% to 100%, more preferably 90% to 100%.

  The thermoplastic resin film of the present invention may be a film composed of a homopolymer or a film composed of a copolymer. Of these, polyester films, polypropylene films, polyamide films and the like are preferable in terms of mechanical properties, dimensional stability, transparency, and polyester films are particularly preferable in terms of mechanical strength and versatility.

  Hereinafter, although the polyester film is demonstrated as a typical example about the thermoplastic resin film of this invention, this invention is not limited to this.

  In the polyester film preferably used as the thermoplastic resin film of the present invention, the polyester is a general term for polymers having an ester bond as a main bond chain, and is ethylene terephthalate, propylene terephthalate, ethylene-2,6. -Mainly at least one component selected from naphthalate, butylene terephthalate, propylene-2,6-naphthalate, ethylene-α, β-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylate, etc. What is used as a constituent can be preferably used. These structural components may be used alone or in combination of two or more. However, if quality, economy, etc. are comprehensively judged, polyester having ethylene terephthalate as a main structural component, that is, polyethylene terephthalate. It is particularly preferable to use In addition, when heat or shrinkage stress acts on the substrate, polyethylene-2,6-naphthalate having excellent heat resistance and rigidity is more preferable. These polyesters may further be partially copolymerized with other dicarboxylic acid components and diol components, preferably 20 mol% or less.

  The polyester also contains various additives such as antioxidants, heat stabilizers, weathering stabilizers, UV absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, antistatic agents. An agent, a nucleating agent, etc. may be added to such an extent that the properties of the polyester are not deteriorated.

  The intrinsic viscosity (measured in o-chlorophenol at 25 ° C.) of the above polyester is preferably 0.4 to 1.2 dl / g, more preferably 0.5 to 0.8 dl / g. It is suitable for carrying out the present invention.

  The polyester film used as the thermoplastic resin film of the electromagnetic wave shielding sheet of the present invention is preferably a biaxially oriented polyester film that is biaxially stretched in a state where a laminated film is formed on at least one surface thereof. The biaxially oriented polyester film is generally an unstretched polyester sheet or film that is stretched about 2.5 to 5 times in the longitudinal direction and the width direction, and then subjected to heat treatment to complete the crystal orientation. Which is a biaxially oriented pattern by wide-angle X-ray diffraction.

  The thickness of the thermoplastic resin film of the present invention is not particularly limited, and is appropriately selected according to the use and type of the electromagnetic wave shielding sheet of the present invention, but the mechanical strength, handling properties, etc. Therefore, it is usually preferably 1 to 500 μm, more preferably 5 to 250 μm, and most preferably 25 to 200 μm.

  Further, the thermoplastic resin film of the present invention may be a composite film obtained by coextrusion. In particular, when a composite film of two or more layers is used, for example, easy slippery fine particles are added to the skin layer, and the core layer is made non-particulate. It's easy to do. On the other hand, the obtained film can also be used by bonding by various methods.

  In addition, the laminated film in the present invention refers to a film-like film that is formed in a laminated structure on at least one surface of a thermoplastic resin film serving as a base material, and the laminated film itself may be a single layer. It may consist of multiple layers. The laminated film of the electromagnetic wave shielding sheet of the present invention is not limited to the case where the laminated film is provided on one side of the thermoplastic resin film as described above, or the case where the laminated film is provided on both sides. It is. Further, the laminated film of the electromagnetic wave shielding sheet of the present invention may be a single layer, two layers, or three or more layers as described above, but is also preferable from the viewpoint of transparency. Is the case of a single layer.

  The laminated film of the electromagnetic wave shielding sheet of the present invention comprises a composition comprising two kinds of polyester resins having different glass transition temperatures and a melamine-based crosslinking agent (C) as constituent components. The composition comprising the polyester resin (A), the polyester resin (B), and the melamine-based cross-linking agent (C) as constituents is 50% by weight or more and 100% by weight or less when the entire laminated film is taken as 100% by weight. More preferably, it is 70 wt% or more and 100 wt% or less, and most preferably 80 wt% or more and 100 wt% or less.

  Furthermore, the laminated film of the present invention needs to have a surface energy of 48 to 55 mN / m. When the surface energy of the laminated film is less than 48 mN / m, the adhesion to the metal layer, particularly the metal layer formed by vapor deposition, is remarkably inferior. For example, the initial adhesion after vapor deposition easily peels off. On the other hand, when the surface energy of the laminated film exceeds 55 mN / m, although the initial adhesion of the metal layer after deposition is relatively good, the wet heat resistance may be particularly inferior. In the present invention, the surface energy of the laminated film is more preferably 48 to 52 mN / m, still more preferably 49 to 52 mN / m.

  Generally, a laminated film having only the surface energy (48 to 55 mN / m) described above can be obtained by various methods. In the present invention, two types having different glass transition temperatures are used. By adding a specific amount of melamine-based crosslinking agent (C) to polyester resin (A) and polyester resin (B), high adhesion to metal layers, particularly vapor-deposited metal layers (initial, moisture and chemical resistance) ) Is obtained.

  The polyester resin having the higher glass transition temperature (hereinafter abbreviated as Tg) of the polyester resin, which is a component of the laminated film according to the present invention, is the polyester resin (A), and the polyester resin having the lower Tg is the polyester resin (B). These will be described.

  In the present invention, two kinds of polyester resins having different Tg are used, but the two kinds of polyester resins have different Tg, and the Tg of the polyester resin (A) is 110 ° C. or more, and the Tg of the polyester resin (B). Copolymerization components such as dicarboxylic acid components and diol components of the polyester resin (A) and the polyester resin (B) are not particularly limited as long as the temperature satisfies 60 ° C or higher and lower than 110 ° C. It is also possible to use the same A) and polyester resin (B).

  The polyester resin (A), which is a component of the laminated film of the present invention, has an ester bond in the main chain or side chain. Such a polyester resin (A) is polycondensed from dicarboxylic acid and diol. It can be obtained.

  As the carboxylic acid component constituting the polyester resin (A), aromatic, aliphatic, and alicyclic dicarboxylic acids and trivalent or higher polyvalent carboxylic acids can be used. As aromatic dicarboxylic acids, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2 -Bisphenoxyethane-p, p'-dicarboxylic acid, phenylindanedicarboxylic acid, etc. can be used.

  These aromatic dicarboxylic acids are preferably 30 mol% or more and 100 mol% or less, more preferably 35 mol% or more in the total dicarboxylic acid component of the polyester resin (A) in terms of the strength and heat resistance of the laminated film. Most preferably, it is 40 mol% or more.

  Aliphatic and alicyclic dicarboxylic acids include succinic acid, adipic acid, sebacic acid, dodecanedioic acid, dimer acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexane Dicarboxylic acids and the like and ester-forming derivatives thereof can be used.

  Moreover, when forming a laminated film by apply | coating a polyester resin (A) or a polyester resin (B) as a water-system resin coating liquid, in order to improve the adhesiveness of a polyester resin (A) or a polyester resin (B), or In particular, in order to facilitate the water-solubilization of the polyester resin (A) or the polyester resin (B), the polyester resin (A) or the polyester resin (B) is combined with a compound containing a sulfonate group or a compound containing a carboxylate group. Polymerization is preferred.

  In the present invention, it is essential to increase the Tg of both the polyester resin (A) and the polyester resin (B). In this case, a carboxylic acid component or a diol component having poor hydrophilicity in terms of copolymer composition is used. Therefore, when the polyester resin is used as a coating solution containing a water-based resin, it is particularly preferable to copolymerize a compound containing a sulfonate group.

  Examples of the compound containing a sulfonate group that are preferably used as a copolymer component of the polyester resin (A) or the polyester resin (B) include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, and 4-sulfonaphthalene. -2,7-dicarboxylic acid, sulfo-p-xylylene glycol, 2-sulfo-1,4-bis (hydroxyethoxy) benzene or the like, or an alkali metal salt, alkaline earth metal salt or ammonium salt thereof may be used. Yes, but not limited to this.

  Examples of the compound containing a carboxylate group that are preferably used as a copolymerization component of the polyester resin (A) or the polyester resin (B) include trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, 4- Methylcyclohexene-1,2,3-tricarboxylic acid, trimesic acid, 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-pentanetetracarboxylic acid, 3,3 ′, 4,4 ′ -Benzophenone tetracarboxylic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3 -Cyclohexene-1,2-dicarboxylic acid, cyclopentanetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid 1,2,5,6-naphthalene tetracarboxylic acid, ethylene glycol bis trimellitate, 2,2 ', 3,3'-diphenyl tetracarboxylic acid, thiophene-2,3,4,5-tetracarboxylic acid, ethylene tetra Carboxylic acid or the like or an alkali metal salt, alkaline earth metal salt or ammonium salt thereof can be used, but is not limited thereto.

  Examples of the diol component of the polyester resin (A) include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5- Pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 2,4-dimethyl-2-ethylhexane-1 , 3-diol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,2 Cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 4,4′-thiodiphenol, bisphenol A, 4,4′-methylenediphenol, 4,4 ′-(2-norbornylidene) diphenol, 4,4′-dihydroxybiphenol, o-, m-, and p-dihydroxybenzene, 4,4′-isopropylidenephenol 4,4′-isopropylidenevindiol, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol, bisphenol A, and the like can be used.

  The polyester preferably used as the polyester resin (A) is an aromatic dicarboxylic acid such as terephthalic acid or 2,6-naphthalenedicarboxylic acid as the carboxylic acid component, and 70 mol% in the total carboxylic acid component of the polyester resin (A). It is preferable to use it after copolymerization of 100 mol% or less. More preferably, an aromatic dicarboxylic acid such as terephthalic acid or 2,6-naphthalenedicarboxylic acid is 85 mol% or more in the total carboxylic acid component of the polyester resin (A) as a carboxylic acid component in terms of water-solubilization of the polyester resin. This is a case where a compound containing 95 mol% or less and a sulfonate group and / or a compound containing a carboxylic acid group is used by copolymerizing 5 mol% or more and 15 mol% or less of all carboxylic acid components. The compound containing a sulfonate group and / or the compound containing a carboxylate group is particularly preferably 5-sulfoisophthalate. Furthermore, as the diol component, it is preferable to use an aliphatic diol such as ethylene glycol or neopentyl glycol by copolymerizing 70 mol% or more and 100 mol% or less in the total diol component of the polyester resin (A). In particular, in order to increase the Tg, it is preferable to use 2,6-naphthalenedicarboxylic acid as the aromatic dicarboxylic acid in the carboxylic acid component.

  The polyester resin (A) used for the laminated film of the present invention can be produced by the following production method. For example, a polyester resin composed of terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid as a dicarboxylic acid component, and ethylene glycol and neopentyl glycol as a diol component will be described. Terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid and ethylene First stage reaction of direct esterification reaction of glycol or neopentyl glycol or transesterification reaction of terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid and ethylene glycol or neopentyl glycol, and this first stage reaction It can be produced by a method of producing the product by a second stage in which the product is subjected to a polycondensation reaction.

  At this time, for example, alkali metal, alkaline earth metal, manganese, cobalt, zinc, antimony, germanium, titanium compound, or the like is used as a reaction catalyst.

  Further, as a method for obtaining a polyester resin (A) having a large amount of carboxylic acid at the terminal and / or side chain, JP-A-54-46294, JP-A-60-209073, JP-A-62-240318 JP, 53-26828, JP 53-26829, JP 53-98336, JP 56-116718, JP 61-124684, JP Although it can be produced from a resin obtained by copolymerization of a trivalent or higher polyvalent carboxylic acid as described in JP-A-62-240318, etc., other methods may be used.

  Further, the intrinsic viscosity of the polyester resin (A) of the laminated film of the present invention is not particularly limited, but is preferably 0.3 dl / g or more, more preferably 0.35 dl / g or more, most preferably in terms of adhesiveness. Preferably it is 0.4 dl / g or more.

  Here, in the present invention, it is an essential requirement that the Tg of the polyester resin (A) is 110 ° C. or higher. This makes it possible to obtain excellent adhesion with a metal layer under normal conditions, and at the same time, high temperature and high temperature. In addition to adhesiveness under moisture, it is possible to have excellent chemical resistance to various chemicals such as organic solvents and acid / alkali solutions. Furthermore, according to the knowledge of the present inventors, the Tg of the polyester resin (A) is preferably 115 ° C. or higher, more preferably 120 ° C. or higher. There is no particular upper limit to the Tg of the polyester resin (A). However, in terms of copolymerization of the resin, subsequent formation of a water-based paint and stability, the practical limit is about Tg 160 ° C.

  Further, the polyester resin (B) has a Tg different from that of the polyester resin (A) described above, and if the Tg is 60 ° C. or higher and lower than 110 ° C., A copolymer component such as a diol component can be used, and a copolymer composition and a copolymer ratio may be selected so as to satisfy the above Tg. Furthermore, according to the knowledge of the present inventors, the Tg of the polyester resin (B) is preferably 65 ° C. or higher and 100 ° C. or lower, more preferably 70 ° C. or higher and 90 ° C. or lower.

  In the present invention, the Tg control method for obtaining a specific Tg range is, for example, controlling the copolymerization ratio of each copolymer component, which controls the ratio of the copolymer component of the carboxylic acid component. The method for controlling the ratio of the copolymer component of the diol component is not particularly limited.

  In terms of imparting excellent adhesion to the mesh-shaped metal layer, for example, 1,4-butanediol or neopentyl glycol is preferably copolymerized as the diol component of the polyester resin (B). In the present invention, since it is necessary to control the Tg of the entire laminated film to be 60 ° C. or higher and lower than 110 ° C., the Tg of the polyester resin (B) is 60 ° C. or higher and 110 ° C. even when the component is copolymerized. It is necessary to adjust so as not to fall outside the range below.

  In the present invention, the polyester preferably used as the polyester resin (B) is terephthalic acid, isophthalic acid, sebacic acid, adipic acid, trimellitic acid, pyromellitic acid, 5- (2,5-dioxotetrahydro) as the carboxylic acid component. Furfuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid, a copolymer selected from ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol as the diol component.

  In particular, as a preferable polyester resin (B), an aromatic dicarboxylic acid such as terephthalic acid or isophthalic acid is used as the carboxylic acid component, and 70 mol% or more and 100 mol% or less of the total carboxylic acid component of the polyester resin (B). This is the case of polymerization. More preferably, the aromatic dicarboxylic acid such as terephthalic acid and isophthalic acid is 85 mol% or more and 95 mol% or less in the total carboxylic acid component of the polyester resin (B) in terms of water-solubilization of the polyester resin (B). In addition, a compound containing a sulfonate group and / or a compound containing a carboxylic acid group is used by copolymerizing 5 mol% or more and 15 mol% or less of the total carboxylic acid component. Furthermore, the compound containing a sulfonate group and / or the compound containing a carboxylate group is particularly preferably 5-sulfoisophthalate. As the diol component, it is preferable to use an aliphatic diol such as ethylene glycol, diethylene glycol, or neopentyl glycol by copolymerizing 70 mol% or more and 100 mol% or less in the total diol component of the polyester resin (B).

  In the laminated film of the present invention, the adhesion to the metal layer is improved by adding the melamine-based crosslinking agent (C) to the polyester resin (A) and the polyester resin (B) described above.

  The melamine-based crosslinking agent (C) used in the present invention is not particularly limited, but is partially or completely obtained by reacting melamine, a methylolated melamine derivative obtained by condensing melamine and formaldehyde, or a methylolated melamine with a lower alcohol. Etherified compounds and mixtures thereof can be used. In particular, the number of methylol group substitutions is preferably 2 to 4 substitutions (6 substitutions are the highest in terms of structure if all substitutions are made). Moreover, as a melamine type crosslinking agent (C), a monomer, the condensate which consists of a multimer more than a dimer, these mixtures, etc. can be used. In addition, as a lower alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol, etc. can be used. The melamine-based cross-linking agent (C) of the present invention has an imino group, a methylol group, or an alkoxymethyl group such as a methoxymethyl group or a butoxymethyl group as a functional group in one molecule, and an imino group type methylated melamine resin. And methylol group-type melamine resin, methylol group-type methylated melamine resin, and fully alkyl-type methylated melamine resin. Of these, methylolated melamine resins are most preferred. Furthermore, in order to accelerate | stimulate the thermosetting of a melamine type crosslinking agent (C), you may use acidic catalysts, such as p-toluenesulfonic acid, for example.

  Moreover, in this invention, as crosslinking agents other than a melamine type crosslinking agent (C), for example, it can carry out a crosslinking reaction with the functional group which exists in a polyester resin, for example, a hydroxyl group, a carboxyl group, etc., acrylamide type, epoxy A compound, an isocyanate compound, an oxazoline compound, various silane coupling agents, various titanate coupling agents, and the like can be used together as a crosslinking agent together with the melamine crosslinking agent (C). Especially, an oxazoline type crosslinking agent can be used suitably at the reactive point with the carboxyl group of the polyester terminal.

  In the laminated film of the electromagnetic wave shielding sheet of the present invention, the mixing ratio of the polyester resin (A) and the polyester resin (B) is not particularly limited as long as both the polyester resin (A) and the polyester resin (B) are included. Although it is good, in order to express the effect of this invention more remarkably, it is good to mix by the following ratios. The weight of the polyester resin (A) and the weight of the polyester resin (B) are “polyester resin (A) / polyester resin (B)” = “90/10” to “20/80” in terms of solid content weight ratio. Is preferable in terms of adhesiveness, more preferably “80/20” to “30/70”, and most preferably “50/50” to “30/70”.

  Furthermore, in the laminated film of the electromagnetic wave shielding sheet of the present invention, the melamine-based crosslinking agent (C) contains 75 to 200 parts by weight with respect to a total of 100 parts by weight of the polyester resin (A) and the polyester resin (B). The adhesion with the layer is greatly improved. More preferably, it is a case where 75 to 150 parts by weight of the melamine-based crosslinking agent (C) is included with respect to a total of 100 parts by weight of the polyester resin (A) and the polyester resin (B), and particularly preferably 100 to 150 parts by weight is included. Thus, it has been found that there are extremely excellent effects in adhesion to the metal layer, wet heat resistance, and chemical resistance.

  In the laminated film, when the melamine-based crosslinking agent (C) is less than 75 parts by weight with respect to 100 parts by weight of the total of the polyester resin (A) and the polyester resin (B), for example, it has excellent adhesion to printing inks and the like. The adhesiveness to the metal layer, which is the effect of the present invention, is insufficient. On the other hand, the melamine-based crosslinking agent (C) is 200 parts by weight with respect to a total of 100 parts by weight of the polyester resin (A) and the polyester resin (B). If it exceeds 1, the characteristics of the cured coating film between the melamine-based crosslinking agents will be exhibited, for example, the releasability will be manifested, and the adhesion to the metal layer will not be obtained.

  Moreover, it is preferable to add inorganic particles, organic particles, or the like to the laminated film of the present invention because the slipperiness and blocking resistance are improved. In this case, silica, colloidal silica, alumina, alumina sol, kaolin, talc, mica, calcium carbonate, or the like can be used as the inorganic particles to be added, and a crosslinked acrylic type or the like is suitably used as the organic particles. The inorganic particles and organic particles used preferably have a number average particle size of 0.01 to 5 μm, more preferably 0.05 to 1 μm, most preferably 0.08 to 0.3 μm, and are mixed with the resin in the laminated film. The ratio is not particularly limited, but is preferably 0.05 to 8 parts by weight, more preferably 0.1 to 3 parts by weight in terms of solid content.

  Moreover, in forming the laminated film of the present invention on one or both sides of the transparent thermoplastic resin film, a water-based resin composed of a polyester resin (A), a polyester resin (B), a melamine-based crosslinking agent (C), etc. As the resin coating method, for example, a reverse coating method, a spray coating method, a bar coating method, a gravure coating method, a rod coating method, a die coating method, or the like can be used.

  Although the thickness of the laminated film of the present invention is not particularly limited, it is usually preferably in the range of 0.005 to 0.2 μm, more preferably 0.01 to 0.1 μm, most preferably 0.01 μm to 0.08 μm. is there. If the thickness of the laminated film is too thin, adhesion failure may occur.

  In producing the electromagnetic wave shielding sheet of the present invention, as a preferred method of providing a laminated film on a thermoplastic resin film, a polyester resin (A), a polyester resin (B), or a melamine-based crosslinking agent (C) is applied to the thermoplastic resin film. The most suitable method is to apply a coating solution containing a specific amount of the above and then stretch it together with the thermoplastic resin film of the present invention.

  For example, when a polyester film is used as the thermoplastic resin film of the present invention, the melt-extruded polyester film before crystal orientation is stretched about 2.5 to 5 times in the longitudinal direction, and continuously to the uniaxially stretched polyester film. A coating solution containing a specific amount of a polyester resin (A), a polyester resin (B), a melamine-based cross-linking agent (C), or the like is applied. The applied polyester film is dried while passing through a zone heated stepwise, and is stretched about 2.5 to 5 times in the width direction. Furthermore, the laminated film of the present invention can be formed on the polyester film by a method (in-line coating method) that is continuously guided to a heating zone of 150 to 250 ° C. to complete the crystal orientation. The coating solution used for forming this laminated film is preferably an aqueous solution from the viewpoint of environmental pollution and explosion resistance. In addition, a simultaneous biaxial stretching method in which a coating solution is continuously applied onto an unstretched polyester film and stretched in the vertical and horizontal directions can be employed.In this case, the film is scratched because there is little contact with the roll. This method is advantageous in that it is difficult to stick.

  Although the kind of metal forming the metal layer provided on the surface of the laminated film of the present invention is not particularly limited, a low resistivity is preferable because the mesh-shaped line width can be narrowed, specifically gold, Silver, copper, aluminum, nickel, chromium, etc. can be mentioned. Among these, considering the low resistivity and production cost, it is most preferable that copper is the main component.

  The method for providing the metal layer on the surface of the laminated film is not particularly limited, but preferably a vacuum vapor deposition method, a sputtering method, an ion plate method, a chemical reaction vapor deposition method, or the like can be used. In the present invention, a vacuum deposition method and a sputtering method, which can form a metal film with high purity, are more preferably used.

  At the production rate of forming the metal layer, vacuum deposition is superior to sputtering, but sputtering is superior to vacuum deposition in terms of the denseness of the metal layer and the adhesion to the laminated film formed on at least one surface of the thermoplastic resin film. As a method of vacuum deposition, it is preferable to evaporate copper by heating by electron beam irradiation rather than resistance heating and induction heating. In some cases, the thermoplastic resin film or the laminated film can be made a metal layer having a lower resistivity by providing a metal layer after removing the gas in the film or the laminated film as much as possible.

  As a method of processing the metal layer formed on the surface of the laminated film into a mesh shape, a method such as a microlithography method or laser ablation can be used. In the present invention, a laser ablation method capable of processing a thin line with high processing accuracy. Alternatively, it is preferable to use a photolithography method.

  Laser ablation means that when a solid surface that absorbs laser light is irradiated with laser light with a high energy density, the bonds between the irradiated parts are broken and evaporated, causing the solid surface of the irradiated part to break. It is a phenomenon that is cut away. By utilizing this phenomenon, the solid surface can be processed. Since laser light is highly straight and condensing, it is possible to selectively process a fine area about three times the wavelength of the laser light used for ablation, and high processing accuracy is obtained by the laser ablation method. I can do it. Moreover, it is possible to process arbitrary shapes by installing a mask in the laser optical path.

  From the viewpoint of not processing the thermoplastic resin film or the laminated film, it is preferable to use an ultraviolet laser having a wavelength of 248 to 533 nm. In particular, when using a solid-state laser, use a second harmonic (wavelength 533 nm) such as Nd: YAG (neodymium: yttrium, aluminum, garnet), more preferably a third harmonic (wavelength 355 nm) such as Nd: YAG. Is more preferable.

  When a gas laser is used, an excimer laser using XeCl or KrF gas having a wavelength of 248 to 308 nm is preferably used.

  As a laser oscillation method, any type of laser can be used. From the viewpoint of processing accuracy, a pulse laser is preferably used, and a pulse laser having a pulse width of 1 μs or less is more preferable.

  From the viewpoint of ablation processing accuracy, the thickness of the metal layer is preferably 0.005 μm or more and 0.5 μm or less. When the thickness of the metal layer exceeds 0.5 μm, it is not preferable because accuracy in processing the metal layer into a mesh shape may be lowered. Moreover, when the thickness of a metal layer is less than 0.005 micrometer, since a metal layer becomes easy to damage, it is unpreferable.

  When using a lithography method as a mesh forming method for processing a metal layer into a mesh shape, a method of etching after forming a resist pattern having a mesh structure on a laminated film on at least one side of a thermoplastic resin film is used. It is done.

  Lithography methods include photolithography method, X-ray lithography method, electron beam lithography method, ion beam lithography method, laser lithography method, etc. In addition to these, screen printing method, intaglio printing method, relief printing method, etc. are also included It is. Among these, the photolithographic method is most preferable from the viewpoint of structure transfer accuracy, simplicity, and mass productivity. Any known method can be used as the etching method. In the etching, the thickness of the metal layer is preferably 0.005 μm or more and 2 μm or less from the viewpoint of the accuracy of the pattern obtained. When the thickness of the metal layer exceeds 2 μm, it is not preferable because accuracy in processing the metal layer into a mesh shape may be lowered. Moreover, when the thickness of a metal layer is less than 0.005 micrometer, since a metal layer becomes easy to damage, it is unpreferable.

  Moreover, when the shielding property of the electromagnetic wave shielding film produced by these methods is insufficient, the shielding property can be enhanced by plating the mesh pattern. Any known method such as electrolysis and electroless plating can be used as the plating method.

  The mesh aperture ratio is desirably 80% or more from the viewpoint of display visibility, and more preferably 90% or more. If the mesh aperture ratio is less than 80%, the brightness of the display may be insufficient. In addition, when the mesh opening ratio is 98% or more, the line width becomes too thin, resulting in insufficient mesh durability, and the mesh is damaged in the pasting process after processing. Therefore, the mesh opening ratio is less than 98%. Preferably there is.

  The interval between the mesh lines is desirably 200 μm or less from the viewpoint of suppressing the occurrence of moire. However, when the mesh interval is extremely narrow, the line width is narrowed to maintain the aperture ratio, and the workability of the metal film is deteriorated. From this point, the mesh line interval is preferably 100 μm or more.

  The filter for PDP using the electromagnetic wave shielding sheet of the present invention can be configured such that layers other than those described above are appropriately laminated as necessary. For example, it is the structure which laminated | stacked the optical filter layer, the surface protective layer, the planarization resin layer, the adhesive material layer, etc. on the electromagnetic wave shield sheet of this invention. These may be known ones in conventional electromagnetic wave shielding sheets.

  For example, the functions of the optical filter layer include near infrared absorption, ultraviolet absorption, antireflection, antiglare prevention, neon light absorption, and color tone adjustment. The functions of the surface protective layer include a hard coat layer and a contamination prevention layer. The smoothing resin layer is a layer formed on the mesh side in order to flatten the unevenness due to the mesh structure, and is a layer that prevents entrainment of bubbles when laminated with the adherend on the mesh side. You may give the function of the said optical filter layer to this layer. The pressure-sensitive adhesive layer has adhesiveness required when the electromagnetic wave shielding sheet is installed on the entire surface of the PDP, and is provided in advance on the electromagnetic wave shielding sheet side. Further, the optical filter may be laminated through such an adhesive layer, or directly bonded to the display front substrate.

<Evaluation method of characteristics>
(1) Thickness of metal layer A cross-section of a sample prepared in Examples and Comparative Examples was cut out with a microtome, and the cross-section was observed with a field emission scanning electron microscope (JSM-6700F manufactured by JEOL Ltd., acceleration voltage 10 kV, observation) The thickness of the metal pattern layer was measured.

About each Example and the comparative example, it measured about five arbitrary places from one sample of 20 cm x 20 cm size, and made the average value the thickness of the metal pattern layer.
(2) Mesh-shaped line width of the metal layer Using a digital microscope (VHX-200) manufactured by Keyence Corporation, surface observation was performed at a magnification of 450 times, and the mesh-shaped fine line was measured using its length measurement function. The width of was measured. A total of 100 fine lines were measured from one arbitrary sample of 20 cm × 20 cm size (4 fine lines for each position), and the average value was taken as the line width of the mesh shape in the sample. Three samples were measured for each example and comparative example, and the average value of the three samples was taken as the line width of the mesh shape in each example and comparative example.

(3) Spacing of mesh shape of metal layer Surface observation was performed at a magnification of 450 times using a digital digital microscope (VHX-200) manufactured by Keyence Corporation. First, attention is paid to an opening A having a certain mesh structure and an opening that shares at least one side with the opening A and is adjacent thereto.

  Next, the distance between the center of gravity of the opening A and the center of gravity of these adjacent openings is measured using the length measuring function of the measuring instrument. Among these measured distances, the shortest distance is set as the mesh interval of the opening A.

Then, from one sample of 20 cm × 20 cm size, the mesh shape interval was measured in the same manner as described above for any 100 openings, and the average value was taken as the mesh shape interval in the sample. Three samples were measured for each of the examples and comparative examples, and the average value of the three samples was taken as the mesh shape interval in each of the examples and comparative examples.
(4) Opening ratio of mesh shape of metal layer Using a digital microscope (VHX-200) manufactured by Keyence Corporation, surface observation is performed at a magnification of 200 times, and its luminance extraction function (histogram extraction, luminance range setting 0) -170) was binarized into an opening (non-conductive metal network) and a conductive metal network.

  The aperture ratio in the field of view was calculated by dividing the area of the opening in the field of view by the total area in the field of view.

For one sample of 20 cm × 20 cm size, the aperture ratio in the visual field was calculated for any 20 locations, and the average value was taken as the aperture ratio in the sample. Three samples were measured for each example and comparative example, and the average value of the three samples was taken as the aperture ratio in each example and comparative example.
(5) Moire evaluation The produced electromagnetic wave shielding member was rotated by 90 ° while being in close contact with a plasma television (VIERA (registered trademark) PX50 manufactured by Matsushita Electric Industrial Co., Ltd.), and the ease of occurrence of moire was evaluated.

  An angle range in which moiré is not visually recognized is 60 ° or more (good: less likely to cause moire), less than 60 ° to 40 ° or more △ (normal: slightly more likely to cause moire), less than 40 ° X (defect: moiré is likely to occur). Moreover, it was set as-when measurement was impossible for other reasons.

Note that three samples were measured for each of the examples and comparative examples, and when the evaluation results were different, the worst evaluation results were adopted.
(6) Mesh adhesion The cellophane tape (CT405AP-18 manufactured by Nichiban Co., Ltd.) is bonded to the metal layer side of the film having the mesh-shaped metal layer thus produced, and the tape end portion has a metal layer mesh. It peeled at 90 degrees with respect to the film.

In the evaluation, the area where the cellophane tape is bonded is 10, and the remaining area is represented by an integer of 0 to 10. The adhesion evaluation was “10” if there was no peeling at all, and the adhesion evaluation was “0” if it was completely peeled off. Moreover, it was set as "x" about what peeled when processing a metal layer into a mesh shape.
(7) Glass transition temperature (Tg)
Connect the SSC5200 disk station manufactured by Seiko Electronics Industry Co., Ltd. to the robot DSC (differential scanning calorimeter) RDC220 manufactured by Seiko Electronics Industry Co., Ltd. And measured.

DSC measurement conditions are as follows. That is, 10 mg of a film sample was adjusted to an aluminum pan, set in a DSC apparatus (reference: aluminum pan of the same type without a sample), heated at 300 ° C. for 5 minutes, and then rapidly cooled in liquid nitrogen Process. This sample was heated at 20 ° C./min, and an extension line of each two baselines was drawn in the vicinity of Tg (showing endothermic behavior in the vicinity of the Tg) in the DSC curve regarding the calorific value. Tg is calculated from the intersection of the two straight lines and the DSC curve.
(8) Surface energy The surface energy in the state which formed the laminated film on the thermoplastic film concerning this invention by the following method was calculated | required. That is, after forming the laminated film on the thermoplastic resin film, the surface energy on the side on which the laminated film was formed was determined.

Four kinds of measurement liquids whose surface energy and each component thereof (dispersion force, polar force, hydrogen bonding force) are known (in the present invention, water described in J. Panzer, J. Colloid Interface Sci., 44, 142 (1973), (Formamide, ethylene glycol, and methylene iodide were used) at a temperature of 23 ° C. and a relative humidity of 65% on a contact angle meter CA-D type (manufactured by Kyowa Interface Science Co., Ltd.) The contact angle of the liquid on the laminated film was measured. The average value of 5 pieces was used for the measurement. Each component was calculated from this value using the following formula introduced from the extended Fowkes formula and Young's formula.
_{^{(Γ S d · γ L d}} ) 1/2 + (γ S p · γ L p) 1/2 + (γ S h · γ L h) 1/2 = γ L (1 + cosθ) / 2
^{_{(However, γ S = γ S d +}} γ S p + γ S h, γ L = γ L d + γ L p + γ L h, ^{_{where, γ S, γ S d,}} γ S p, γ S h , respectively, laminated Represents the surface energy, dispersion force component, polar force component, and hydrogen bond force component of the film. Γ _L , γ _L ^d , γ _L ^p , and γ _L ^h are the surface energy, dispersion force component, and polarity of the measurement solution used, respectively. Represents the force component and the hydrogen bonding force component, and θ represents the contact angle of the measurement liquid on the laminated film.)
The θ obtained for each liquid, the surface energy of the measurement liquid, and the value of each component thereof were substituted into the above equations, and the simultaneous equations were solved to obtain the surface energy of the laminated film.

Example 1
PET pellets (extreme viscosity 0.63 dl / g) that do not contain external particles are sufficiently dried in vacuum, then supplied to an extruder, melted at a temperature of 285 ° C., extruded from a T-shaped die into a sheet, and electrostatically applied. It was wound around a mirror-casting drum having a surface temperature of 25 ° C. using a casting method and cooled and solidified.

  The unstretched film thus obtained was heated to a temperature of 88 ° C. and stretched 3.3 times in the longitudinal direction to obtain a uniaxially stretched film.

  The uniaxially stretched film was subjected to corona discharge treatment in the air, and the following laminated film forming coating solution was applied to the treated surface.

  The uniaxially stretched film coated with the laminated film forming coating liquid is guided to a preheating zone while being held by a clip, dried at a temperature of 95 ° C., and continuously 3.4 in the width direction in a heating zone at a temperature of 110 ° C. The film was stretched twice and further subjected to a heat treatment in a heating zone at a temperature of 235 ° C. to obtain a laminated PET film (polyethylene terephthalate film) composed of a laminated film and a thermoplastic resin film, in which crystal orientation was completed.

The thickness of only the PET film excluding the laminated film was 100 μm, and the thickness of the laminated film was 0.08 μm.
"Laminated film forming coating solution"
-Coating liquid A1:
An aqueous dispersion of a polyester resin (glass transition temperature: 110 ° C.) having the following copolymer composition.
<Copolymerization component>
Naphthalenedicarboxylic acid 75 mol%
Terephthalic acid 15 mol%
5-Na sulfoisophthalic acid 10 mol%
Ethylene glycol 95 mol%
Diethylene glycol 5 mol%.

-Coating liquid B1:
An aqueous dispersion of a polyester resin (glass transition temperature: 82 ° C.) having the following copolymer composition.
<Copolymerization component>
Terephthalic acid 88 mol%
5-Na sulfoisophthalic acid 12 mol%
99 mol% ethylene glycol
Diethylene glycol 1 mol%.

・ Coating liquid C1:
A coating solution obtained by diluting a methylolated melamine-based crosslinking agent (Sanwa Chemical Co., Ltd. “Nikalac” MW-12LF) in a mixed solvent of isopropyl alcohol and water (10/90 (weight ratio)).

  The above-described coating liquid A1 and coating liquid B1 are mixed at a solid content weight ratio of coating liquid A1 / coating liquid B1 = 30/70, and the total liquid weight of A1 and A2 is 100 parts by weight. A mixed liquid for forming a laminated film was prepared by mixing 75 parts by weight of C1 in terms of solid content.

At this time, the solid content weight ratio of each coating liquid was coating liquid A1 / coating liquid B1 / coating liquid C1 = 30/70/75.
A metal layer made of 0.1 μm copper was provided on the laminated film forming surface side of the laminated PET film made of this laminated film and a thermoplastic resin film by a sputtering apparatus.

  The purity of the copper target was 99.99% and was sputtered with argon plasma. The sputtering power was 7 kW, and the film conveyance speed was 1 m / min.

Then, the metal layer which is a copper sputtered film was processed into the mesh shape by irradiating with a XrF excimer laser with a wavelength of 248 nm through a lattice mask and performing laser ablation. An electromagnetic wave shielding sheet having a mesh shape of a square lattice, a line width of 8 μm, a lattice interval of 150 μm, and an aperture ratio of 90% was obtained. The moire evaluation was ○, and the adhesion was 10.
(Example 2)
A metal layer made of copper having a thickness of 0.3 μm was provided on the laminated film forming surface side of the laminated PET film made of the laminated film and the thermoplastic resin film subjected to the same processing treatment as in Example 1 by an electron beam type vapor deposition machine. .

  The purity of the copper vapor deposition material was 99.99%.

  Subsequently, an XrF excimer laser with a wavelength of 248 nm was irradiated, and a metal layer made of copper was processed into a mesh shape by laser ablation.

An electromagnetic wave shield sheet having a mesh shape of a square lattice, a line width of 10 μm, a lattice interval of 150 μm, and an aperture ratio of 87% was obtained. The moire evaluation was ○, and the adhesion was 10.
(Example 3)
A metal layer made of 0.3 μm copper was provided on the laminated film forming surface side of the laminated PET film made of the laminated film and the thermoplastic resin film subjected to the same processing treatment as in Example 1 by an electron beam type vapor deposition machine.

  The purity of the copper vapor deposition material was 99.99%.

  Subsequently, the metal layer made of copper was processed into a mesh shape by laser ablation by irradiating the third harmonic of a YAG laser having a wavelength of 355 nm.

An electromagnetic wave shielding sheet having a mesh shape of a square lattice, a line width of 8 μm, a lattice interval of 100 μm, and an aperture ratio of 85% was obtained. The moire evaluation was good and the adhesion was 10.
Example 4
A metal layer made of 2 μm copper was provided on the laminated film forming surface side of the laminated PET film made of the laminated film and the thermoplastic resin film subjected to the same processing treatment as in Example 1 by an electron beam type vapor deposition machine.

  The purity of the copper vapor deposition material was 99.99%.

An electromagnetic wave shielding sheet having a line width of 10 μm, a lattice interval of 200 μm, and an aperture ratio of 90% was obtained by a photolithography process (resist film attachment-exposure-development-chemical etching-resist peeling) on the surface of the obtained metal layer made of copper. . The moire evaluation was good and the adhesion was 10.
(Example 5)
A metal layer made of copper of 0.05 μm was provided on the laminated film forming surface side of a laminated PET film made of a laminated film and a thermoplastic resin film subjected to the same processing treatment as in Example 1 by an electron beam type vapor deposition machine.

  The purity of the copper vapor deposition material was 99.99%.

  Subsequently, an XrF excimer laser with a wavelength of 248 nm was irradiated, and a metal layer made of copper was processed into a mesh shape by laser ablation.

  The mesh shape was a square lattice with a line width of 6 μm and a lattice spacing of 150 μm.

By subjecting the obtained mesh to electrolytic plating, the Cu film thickness was set to 2 μm. An electromagnetic wave shielding sheet having a line width of 9 μm, a lattice spacing of 150 μm, and an aperture ratio of 87% was obtained. The moire evaluation was ○, and the adhesion was 9.
(Comparative Example 1)
A laminated PET film composed of a laminated film and a thermoplastic resin film was obtained in the same manner as in Example 1 except that the following laminated film forming coating liquid was used instead of the laminated film forming coating liquid used in Example 1. It was.
"Laminated film forming coating solution"
-Coating liquid D1:
An aqueous emulsion copolymerized with the following acrylic monomers.
<Copolymerization component>
65% by weight methyl methacrylate
Ethyl acrylate 32% by weight
Acrylic acid 2% by weight
N-methylolacrylamide 1% by weight
A solution obtained by mixing 100 parts by weight of the coating liquid C1 with respect to 100 parts by weight of the coating liquid D1 was used as a laminated film forming coating liquid.

  In addition, the solid content weight ratio of each coating liquid was coating liquid D1 / coating liquid C1 = 100/100 at this time.

  A metal layer made of 0.3 μm copper was provided on the laminated film forming surface side by a sputtering apparatus.

  The purity of the copper target was 99.99% and was sputtered with argon plasma. The sputtering power was 7 kW, and the film conveyance speed was 1 m / min.

Subsequently, when an XrF excimer laser with a wavelength of 248 nm was irradiated and laser ablation was performed, peeling of the mesh occurred and it was impossible to form a pattern.
(Comparative Example 2)
A laminated PET film comprising a laminated film and a thermoplastic resin film was obtained in the same manner as in Example 1 except that the following laminated film forming coating liquid was used instead of the laminated film forming coating liquid used in Example 1. .
"Laminated film forming coating solution"
The same coating liquid A1 and coating liquid C1 as in Example 1 were used.
A solution obtained by mixing 100 parts by weight of the coating liquid C1 with respect to 100 parts by weight of the coating liquid A1 was used as a laminated film forming coating liquid. In addition, the solid content weight ratio of each coating liquid at this time was coating liquid A1 / coating liquid C1 = 100/100.

  A metal layer made of copper having a thickness of 0.3 μm was provided on the laminated film forming surface side of the laminated PET film made of this laminated film and a thermoplastic resin film by an electron beam type vapor deposition machine.

  The purity of the copper vapor deposition material was 99.99%.

  Subsequently, an XrF excimer laser with a wavelength of 248 nm was irradiated, and a metal layer made of copper was processed into a mesh shape by laser ablation.

An electromagnetic wave shield sheet having a mesh shape of a square lattice, a line width of 10 μm, a lattice interval of 150 μm, and an aperture ratio of 87% was obtained. The moire evaluation was ○, and the adhesion was 3.
(Comparative Example 3)
A laminated PET film comprising a laminated film and a thermoplastic resin film was obtained in the same manner as in Example 1 except that the following laminated film forming coating liquid was used instead of the laminated film forming coating liquid used in Example 1. .
"Laminated film forming coating solution"
The same coating liquid B1 and coating liquid C1 as in Example 1 were used.
A solution obtained by mixing 100 parts by weight of the coating liquid C1 with respect to 100 parts by weight of the coating liquid B1 was used as a laminated film forming coating liquid. At this time, the solid content weight ratio of each coating liquid was coating liquid B1 / coating liquid C1 = 100/100.

  A metal layer made of copper having a thickness of 0.3 μm was provided on the laminated film forming surface side of the laminated PET film made of this laminated film and a thermoplastic resin film by an electron beam type vapor deposition machine.

  The purity of the copper vapor deposition material was 99.99%.

  Subsequently, an XrF excimer laser with a wavelength of 248 nm was irradiated, and a metal layer made of copper was processed into a mesh shape by laser ablation.

An electromagnetic wave shield sheet having a mesh shape of a square lattice, a line width of 10 μm, a lattice interval of 150 μm, and an aperture ratio of 87% was obtained. The moire evaluation was ○, and the adhesion was 2.
(Comparative Example 4)
A laminated PET film comprising a laminated film and a thermoplastic resin film was obtained in the same manner as in Example 1 except that the following laminated film forming coating liquid was used instead of the laminated film forming coating liquid used in Example 1. .
"Laminated film forming coating solution"
The same coating liquid A1 and coating liquid B1 as in Example 1 were used.
The above-described coating liquid A1 and coating liquid B1 were mixed at a solid content weight ratio of coating liquid A1 / coating liquid B1 = 30/70 to obtain a laminated film forming coating liquid. In addition, the solid content weight ratio of each coating liquid at this time was coating liquid A1 / coating liquid B1 = 30/70 (the melamine type crosslinking agent was not added).

  A metal layer made of copper having a thickness of 0.3 μm was provided on the laminated film forming surface side of the laminated PET film made of this laminated film and a thermoplastic resin film by an electron beam type vapor deposition machine.

  The purity of the copper vapor deposition material was 99.99%.

  Subsequently, an XrF excimer laser with a wavelength of 248 nm was irradiated, and a metal layer made of copper was processed into a mesh shape by laser ablation.

An electromagnetic wave shield sheet having a mesh shape of a square lattice, a line width of 10 μm, a lattice interval of 150 μm, and an aperture ratio of 87% was obtained. The moire evaluation was ○, and the adhesion was 2.
(Comparative Example 5)
A laminated PET film comprising a laminated film and a thermoplastic resin film was obtained in the same manner as in Example 1 except that the following laminated film forming coating liquid was used instead of the laminated film forming coating liquid used in Example 1. .
"Laminated film forming coating solution"
The same coating liquid A1, coating liquid B1, and coating liquid C1 as in Example 1 were used.
The above-described coating liquid A1 and coating liquid B1 are mixed at a solid content weight ratio of coating liquid A1 / coating liquid B1 = 30/70, and 50 parts by weight of the coating liquid C1 is mixed with 100 parts by weight. A laminated film forming coating solution was obtained. At this time, the weight ratio of the solid content of each coating liquid was coating liquid A1 / coating liquid B1 / coating liquid C1 = 30/70/50.

  A metal layer made of copper having a thickness of 0.3 μm was provided on the laminated film forming surface side of the laminated PET film made of this laminated film and a thermoplastic resin film by an electron beam type vapor deposition machine.

  The purity of the copper vapor deposition material was 99.99%.

  Subsequently, an XrF excimer laser with a wavelength of 248 nm was irradiated, and a metal layer made of copper was processed into a mesh shape by laser ablation.

  An electromagnetic wave shield sheet having a mesh shape of a square lattice, a line width of 10 μm, a lattice interval of 150 μm, and an aperture ratio of 87% was obtained. The moire evaluation was ○, and the adhesion was 4.

(Comparative Example 6)
A laminated PET film comprising a laminated film and a thermoplastic resin film was obtained in the same manner as in Example 1 except that the following laminated film forming coating liquid was used instead of the laminated film forming coating liquid used in Example 1. .
"Laminated film forming coating solution"
The same coating liquid A1, coating liquid B1, and coating liquid C1 as in Example 1 were used.
The above-described coating liquid A1 and coating liquid B1 are mixed at a solid content weight ratio of coating liquid A1 / coating liquid B1 = 30/70, and a mixture of 250 parts by weight of the coating liquid C1 with respect to 100 parts by weight. A laminated film forming coating solution was obtained. At this time, the solid content weight ratio of each coating liquid was coating liquid A1 / coating liquid B1 / coating liquid C1 = 30/70/250.

  A metal layer made of copper having a thickness of 0.3 μm was provided on the laminated film forming surface side of the laminated PET film made of this laminated film and a thermoplastic resin film by an electron beam type vapor deposition machine.

  The purity of the copper vapor deposition material was 99.99%.

  Subsequently, an XrF excimer laser with a wavelength of 248 nm was irradiated, and a metal layer made of copper was processed into a mesh shape by laser ablation.

An electromagnetic wave shield sheet having a mesh shape of a square lattice, a line width of 10 μm, a lattice interval of 150 μm, and an aperture ratio of 87% was obtained. The moire evaluation was ○, and the adhesion was 3.
(Comparative Example 7)
A laminated PET film comprising a laminated film and a thermoplastic resin film was obtained in the same manner as in Example 1 except that the following laminated film forming coating liquid was used instead of the laminated film forming coating liquid used in Example 1. .
"Laminated film forming coating solution"
The same coating liquid A1, coating liquid B1, and coating liquid C1 as in Example 1 were used.
・ Coating fluid F1:
An aqueous solution of polystyrene sulfonate ammonium salt (weight average molecular weight: 10,000).

  The above-mentioned coating liquid A1 and coating liquid B1 are mixed at a solid content weight ratio of coating liquid A1 / coating liquid B1 = 30/70, and 100 parts by weight of the coating liquid C1 and the coating liquid F1 with respect to 100 parts by weight. 10 parts by weight of the mixture was used as a laminated film forming coating solution. At this time, the solid content weight ratio of each coating liquid was coating liquid A1 / coating liquid B1 / coating liquid C1 / coating liquid F1 = 30/70/100/10.

  A metal layer made of copper having a thickness of 0.3 μm was provided on the laminated film forming surface side of the laminated PET film made of this laminated film and a thermoplastic resin film by an electron beam type vapor deposition machine.

  The purity of the copper vapor deposition material was 99.99%.

  Subsequently, an XrF excimer laser with a wavelength of 248 nm was irradiated, and a metal layer made of copper was processed into a mesh shape by laser ablation.

An electromagnetic wave shield sheet having a mesh shape of a square lattice, a line width of 10 μm, a lattice interval of 150 μm, and an aperture ratio of 87% was obtained. The moire evaluation was ○, and the adhesion was 0.
(Comparative Example 8)
A metal layer made of 0.3 μm copper was provided on the laminated film surface side of a laminated PET film made of a laminated film and a thermoplastic resin film subjected to the same processing treatment as Comparative Example 1 by an electron beam type vapor deposition machine.

  The purity of the copper vapor deposition material was 99.99%.

  Subsequently, the metal layer made of copper was processed into a mesh shape by laser ablation by irradiating the third harmonic of a YAG laser having a wavelength of 355 nm.

  An electromagnetic wave shield sheet having a mesh shape of a square lattice, a line width of 10 μm, a lattice interval of 150 μm, and an aperture ratio of 87% was obtained.

  Although the moire evaluation was good, the adhesion was 0.

(Comparative Example 9)
A metal layer made of 0.3 μm copper was provided on the laminated film surface of the laminated PET film made of the laminated film and the thermoplastic resin film subjected to the same processing as in Comparative Example 1 by an electron beam type vapor deposition machine.

  The purity of the copper vapor deposition material was 99.99%.

  A pattern was prepared on the obtained copper surface by a photolithography process (resist film attachment-exposure-development-chemical etching-resist peeling).

  However, since the peeling of the mesh occurred in the resist peeling process, an electromagnetic wave shield sheet could not be obtained.

(Comparative Example 10)
A metal layer made of 0.3 μm copper was provided on the laminated film surface of the laminated PET film made of the laminated film and the thermoplastic resin film subjected to the same processing treatment as in Example 1 by an electron beam vapor deposition machine.

  The purity of the copper vapor deposition material was 99.99%.

  Subsequently, an XrF excimer laser with a wavelength of 248 nm was irradiated through a lattice mask to perform laser ablation, thereby processing the copper sputtered film into a mesh shape.

  An electromagnetic wave shielding sheet having a mesh shape of a square lattice, a line width of 13 μm, a lattice interval of 250 μm, and an aperture ratio of 90% was obtained.

  However, the moiré frequency of this sample was Δ.

(Comparative Example 11)
A metal layer made of 0.3 μm copper was provided on the laminated film surface of the laminated PET film made of the laminated film and the thermoplastic resin film subjected to the same processing treatment as in Example 1 by an electron beam vapor deposition machine.

  The purity of the copper vapor deposition material was 99.99%.

  Subsequently, the copper vapor deposition film was processed into a mesh shape by laser ablation by irradiating an XrF excimer laser having a wavelength of 248 nm through a lattice mask.

  An electromagnetic wave shielding sheet having a mesh shape of a square lattice, a line width of 25 μm, a lattice interval of 250 μm, and an aperture ratio of 81% was obtained.

  However, the moiré frequency of this sample was x.

  The present invention can be used not only as an electromagnetic wave shielding sheet for plasma display but also as any electromagnetic wave shielding sheet, but its application range is not limited to these.

Claims (7)

On at least one side of the thermoplastic resin film,
Surface energy is 48-, comprising a polyester resin (A) having a glass transition temperature of 110 ° C. or higher, a polyester resin (B) having a glass transition temperature of 60 ° C. or higher and lower than 110 ° C., and a melamine crosslinking agent (C). Having a laminated film of 55 mN / m,
The laminated film contains 75 to 200 parts by weight of the melamine crosslinking agent (C) with respect to 100 parts by weight of the total of the polyester resin (A) and the polyester resin (B).
An electromagnetic wave shielding sheet having a mesh-shaped metal layer on the surface of the laminated film.   The electromagnetic wave shielding sheet according to claim 1, wherein the polyester resin (A) and / or the polyester resin (B) is a polyester resin containing a sulfonate group.   The laminated film includes 100 to 150 parts by weight of the melamine-based crosslinking agent (C) with respect to 100 parts by weight of the total of the polyester resin (A) and the polyester resin (B). The electromagnetic wave shielding sheet according to 1 or 2.   The metal layer is formed by any one of a vacuum vapor deposition method, a chemical reaction vapor deposition method, and a sputtering method, and the thickness of the metal layer is 2 to 0.005 µm. An electromagnetic shielding sheet according to crab.   The electromagnetic wave shielding sheet according to claim 1, wherein the mesh is formed by a lithography method or a laser ablation method.   The electromagnetic wave shielding sheet according to claim 1, wherein the mesh line spacing is 100 to 200 μm and the mesh opening ratio is 80% or more. A filter for PDP using the electromagnetic wave shielding sheet according to claim 1.