JP2009252868A - Light permeable electromagnetic shielding material and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-permeable electromagnetic shielding material which is superior in electromagnetic shieldability with substantially no moires produced, and to provide a manufacturing method of the light-permeable electromagnetic shielding material which is superior in the electromagnetic shieldability having substantially no moires. <P>SOLUTION: The light permeable electromagnetic shielding material is provided with a transparent substrate and a mesh-like metal conductive layer provided on it, and the line width of the mesh of the metal conductive layer is varied. It is preferable that the line width alternately form a maximum value and the minimum value, in at least a part of the area of the mesh. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light-transmitting electromagnetic wave shielding material used for a front filter of a plasma display panel (PDP) and a window of a building such as a hospital that requires an electromagnetic wave shielding, and a method for producing the light-transmitting electromagnetic wave shielding material.

  In recent years, large screen displays have become the mainstream of displays, and PDPs have become common as liquid crystal displays as large screen display devices. PDP has advantages such as faster response speed than liquid crystal display. However, in this PDP, high-frequency pulse discharge is performed on the light emitting part for image display, and there is a risk of unnecessary electromagnetic radiation and infrared radiation that may cause malfunction of the infrared remote control, etc. For this purpose, various PDP filters (light-transmitting electromagnetic wave shielding materials) having conductivity have been proposed for PDP. Examples of the conductive layer of this light-transmitting electromagnetic wave shielding material include (1) a transparent conductive thin film containing metallic silver, (2) a conductive mesh made of a metal wire or conductive fiber, and (3) copper on the transparent film. Known are those in which a layer of foil or the like is etched into a net and an opening is provided, and (4) a conductive ink is printed on a transparent film in a mesh.

  However, the transparent conductive thin film of (1) has a drawback that sufficient conductivity cannot be obtained, and that the conductive mesh of (2) generally cannot obtain good light transmittance. Since the desired mesh-like conductive layer can be formed by the etching process of (3) and (4) pattern printing, the degree of freedom of the line width, spacing, and mesh shape is much larger than that of the conductive mesh. Even a mesh-shaped conductive layer having a high opening ratio with a thin line having a width of 200 μm or less and an opening ratio of 75% or more can be formed. However, (3) is disadvantageous in that it requires equipment for the etching process, and the process is complicated and expensive. On the other hand, (4) mesh-like pattern printing is particularly easy and advantageous for the formation of the conductive layer described above. Can be obtained.

  The method (4) for producing a conductive layer is described in, for example, Patent Document 1 (Patent No. 3017988). In this method, after intaglio offset printing using a cylinder excellent in ink releasability, a conductive ink containing metal powder and resin is printed on the surface of a transparent substrate to form a pattern with specific dimensions, This pattern is cured, and then a metal film is provided only on the surface of the pattern by electroplating. That is, a pattern line generated when a pattern having a line width of 50 μm or less is printed by a conventional screen printing method or gravure printing method by electroplating a pattern (conductive film) having a specific dimension printed by intaglio offset printing. This is to eliminate disadvantages such as width variation and disconnection.

Patent No. 3017988

  However, in the conventional mesh-like conductive layer, including the mesh-like conductive ink layer by intaglio offset printing as described above, each line of the mesh is a straight line having a substantially uniform line width. The mesh lines have a clear periodic structure. When the light-transmitting electromagnetic wave shielding material having such a periodic structure mesh is mounted on a display, moire tends to be generated depending on the display.

  Accordingly, an object of the present invention is to provide a light-transmitting electromagnetic wave shielding material which is excellent in electromagnetic wave shielding properties and hardly causes moire.

  Another object of the present invention is to provide a light-transmitting electromagnetic wave shielding material that is excellent in electromagnetic wave shielding properties, hardly generates moire, and has excellent light transmission and visibility.

  A further object of the present invention is to provide a method for producing a light-transmitting electromagnetic wave shielding material which is excellent in the electromagnetic wave shielding properties and hardly causes moiré.

The present invention
Having a transparent substrate, and a mesh-like metal conductive layer provided thereon,
A light-transmitting electromagnetic wave shielding material, wherein the line width of the mesh of the metal conductive layer varies;
It is in.

Preferred embodiments of the light transmissive electromagnetic wave shielding material of the present invention are listed below.
(1) In at least a partial region of the mesh (preferably in at least one direction of lines constituting the mesh), the line width alternately forms a maximum value and a minimum value. The suppression effect of moiré is improved.
(2) In at least a partial region of the mesh, the difference between the maximum value of the line width and the adjacent minimum value is larger than 5% and smaller than 20% of the average line width of the mesh. The suppression effect of moiré is improved.
(3) In at least a partial region of the mesh, the distance between the maximum value of the line width and the adjacent maximum value is smaller than the inter-line distance (pitch) of the mesh and larger than 10% of the pitch. The suppression effect of moiré is improved.
(4) A mesh-shaped pretreatment layer is provided between the transparent substrate and the metal conductive layer. Excellent conductivity is easily obtained.

The present invention also provides:
Forming a mesh-like pretreatment layer by pattern-printing an electroless plating pretreatment agent on the surface of the transparent substrate; and forming a mesh-like metal conductive layer on the pretreatment layer by an electroless plating treatment;
A method for producing a light-transmitting electromagnetic wave shielding material comprising:
A production method, wherein the mesh-shaped pretreatment layer is formed so that the line width of the mesh varies;
There is also.

The preferable aspect of the manufacturing method of the said light-transmitting electromagnetic wave shielding material of the said invention is enumerated below.
(1) The electroless plating pretreatment agent is a liquid containing a composite metal oxide and / or a composite metal oxide hydrate and a synthetic resin. In the above method, particularly excellent conductivity is easily obtained.
(2) The electroless plating pretreatment agent is a liquid containing a mixture or reaction product of a silane coupling agent and an azole compound, and a noble metal compound. Excellent conductivity is easily obtained.
(3) After performing electroless plating, electrolytic plating is further performed. Excellent conductivity is obtained.

  Preferred embodiments (1) to (4) of the light transmissive electromagnetic wave shielding material can also be applied to this production method.

Furthermore, the present invention provides
In the method for producing a light-transmitting electromagnetic wave shielding material including a step of forming a mesh-like conductive layer by pattern printing a conductive ink containing metal fine particles and a binder resin on the surface of a transparent substrate,
A manufacturing method, wherein the mesh-like conductive layer is formed so that the line width of the mesh varies;
There is also.

The preferable aspect of the manufacturing method of the said light-transmitting electromagnetic wave shielding material of the said invention is enumerated below.
(1) Electrolytic plating is performed on the mesh-like conductive layer.

  Preferred embodiments (1) to (4) of the light transmissive electromagnetic wave shielding material can also be applied to this production method.

  The light-transmitting electromagnetic wave shielding material of the present invention and the light-transmitting electromagnetic wave shielding material obtained by the production method of the present invention can be advantageously used for display filters; in particular, plasma display panel filters.

  Since the light-transmitting electromagnetic wave shielding material of the present invention does not have a periodic structure because the mesh line width of the mesh-like conductive layer fluctuates, it interferes with the pixel cell pitch, black matrix, etc. when mounted on a display. Is less likely to occur and moire is less likely to occur. Therefore, the light-transmitting electromagnetic wave shielding material of the present invention has excellent conductivity and hardly generates moiré.

  The light transmissive electromagnetic wave shielding material and the method for producing the light transmissive electromagnetic wave shielding material of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic cross-sectional view of one example of the light-transmitting electromagnetic wave shielding material of the present invention. On the transparent substrate 11, a metal conductive layer 13 is formed which has a mesh shape and the line width of the mesh varies according to the present invention. An electroless plating pretreatment layer is preferably provided between the transparent substrate 11 and the metal conductive layer 13. That is, the formation of a metal conductive layer using such a pretreatment layer is preferable because high conductivity is easily obtained.

  FIG. 2 is a schematic plan view of the light transmissive electromagnetic wave shielding material of the present invention, and FIG. 3 is a partially enlarged view thereof. As shown in FIG. 2, the metal conductive layer 13 is provided in a mesh shape (lattice shape), and the line width of the mesh-like metal conductive layer 13 varies. For example, the metal conductive layer 13 has a shape as shown in FIG. is doing.

In the present invention, the lines constituting the mesh of the mesh-like metal conductive layer 13 are provided so that the line width alternately forms a maximum value (W _max ) and a minimum value (W _min ). In FIG. 3, lines in all two directions are provided so as to alternately form a maximum value (W _max ) and a minimum value (W _min ). However, as long as moire can be prevented, the maximum value (W _{The range in which max} ) and the minimum value ( _Wmin ) are alternately formed can be set as appropriate. Therefore, such a range may be partial. It is preferable to provide a maximum value (W _max ) and a minimum value (W _min ) alternately in at least one direction.

As shown in FIG. 3, the difference (Rz) between the maximum value (W _max ) of the line width and the adjacent minimum value (W _min ) is larger than 5% of the average line width of the mesh, more than 40% ( In particular, it is preferably smaller than 20%. When it is 5% or less, it is difficult to obtain the moire prevention effect, and when it is 40% or more, the mesh line is likely to be disconnected at the position of the minimum value. As long as moire can be prevented, the range can be set as appropriate. Therefore, a partial area of the mesh may satisfy the above range. The average line width of the mesh is generally 20 μm or less, preferably 5 to 15 μm, particularly preferably 5 to 12 μm.

Furthermore, in the present invention, the average (S ′) of the distance between the maximum value (W _max ) of the line width and the adjacent maximum value (W _max ) is the distance between lines of the mesh (pitch: 2 adjacent meshes). Preferably less than the distance between the centers of the lines) and greater than 10% of the pitch. More preferably, each distance (S) that is not an average between the maximum values satisfies the above range. When it is 10% or less, it is difficult to obtain the moire preventing effect, and when it is more than the pitch, it is difficult to obtain the moire preventing effect. As long as the above relationship is within a range where moire can be prevented, it is sufficient that at least a portion of the mesh satisfies the above range.

  It is preferable that the mesh region having any one of the above relationships (preferably both relationships) has at least 20% or more of the total area of the metal conductive layer.

  As shown in FIG. 3, it is preferable that two or more sides of the four sides of the cross including the vertexes included in four adjacent meshes sharing the vertex have different shapes, and particularly, three or more sides have different shapes. It is preferable.

  FIG. 4 is an enlarged plan view showing an example of a region wider than the example of FIG. 3 in the mesh-shaped metal conductive layer 13 of the present invention.

  FIG. 5 shows an example of the mesh shape of the mesh-like metal conductive layer 13 as shown in the present invention. In (1) and (2), the case where the distance (S) between the maximum values is larger than in FIG. 3 is shown. (3) shows a case where the distance (S) between the maximum values is smaller than in FIG.

  As shown in FIGS. 1 to 4, the light-transmitting electromagnetic wave shielding material of the present invention has a periodic structure because the line width of the mesh of the mesh-like conductive layer fluctuates. Interference with the cell pitch, black matrix, etc. hardly occurs, and moire hardly occurs. Therefore, the light-transmitting electromagnetic wave shielding material of the present invention has excellent conductivity and hardly generates moiré.

In the present invention, the method for producing a light-transmitting electromagnetic wave shielding material is preferably the following three methods:
(A) A step of forming a mesh-shaped pretreatment layer by pattern printing using a liquid containing a composite metal oxide and / or a composite metal oxide hydrate and a synthetic resin as an electroless plating pretreatment agent; Forming a mesh-like metal conductive layer on the treatment layer by electroless plating,
A production method comprising:
(B) A step of forming a mesh-shaped pretreatment layer by pattern printing using a liquid containing a mixture or reaction product of a silane coupling agent and an azole compound and a noble metal compound as a pretreatment agent for electroless plating, And forming a mesh-like metal conductive layer on the pretreatment layer by electroless plating,
And (C) using a method for producing a light-transmitting electromagnetic wave shielding material comprising a step of pattern-printing a conductive ink containing metal fine particles and a binder resin on the surface of a transparent substrate to form a mesh-like conductive layer It is preferable to do. Each method will be described in detail below.

  FIG. 6 shows a schematic cross-sectional view for explaining the method (A) for producing a light-transmitting electromagnetic wave shielding material of the present invention. First, as shown in (A1) and (A2), an electroless plating pretreatment agent containing a composite metal oxide and / or composite metal oxide hydrate and a synthetic resin on a transparent substrate 61 such as a transparent film. According to the method of the present invention, printing is performed in a mesh shape, and after drying, a mesh-shaped pretreatment layer 62 is formed on the transparent substrate 61. Then, by performing electroless plating on the pretreatment layer 62, a mesh-like metal conductive layer 63 made of a conductive material such as metal is formed on the pretreatment layer 62.

  For the electroless plating pretreatment agent containing the composite metal oxide and / or the composite metal oxide hydrate and the synthetic resin, for example, an intaglio having a specific shape corresponding to the mesh shape with varying line width of the present invention is used. It is printed by intaglio printing. As a result, it is possible to accurately form a mesh-shaped pretreatment layer having a fine pattern with no streaking or fogging. By performing an electroless plating process on such a mesh-shaped pretreatment layer, it is possible to form a mesh-shaped metal conductive layer with a varying line width with almost no moire.

  The intaglio printing is preferably gravure printing or gravure offset printing, which enables high-precision printing.

  The composite metal oxide and composite metal oxide hydrate used for the electroless plating pretreatment agent include those containing at least two metal elements selected from the group consisting of Pd, Ag, Si, Ti, and Zr. Preferably used. More preferable examples include those containing a metal element of Pd or Ag and a metal element of Si, Ti or Zr. Such composite metal oxides and composite metal oxide hydrates have high plating metal deposition ability, and further have excellent stability and dispersibility in the pretreatment agent.

Especially, since the said characteristic is especially excellent, following formula (I)
M ¹ _X · M ² O ₂ · n (H ₂ O) (I)
(In the formula, M ¹ represents Pd or Ag, M ² represents Si, Ti, or Zr. When M ¹ is Pd, x is 1, and when M ¹ is Ag, x is 2. And n is an integer of 1 to 20), and it is particularly preferable to use a composite metal oxide hydrate.

In formula (I), M ¹ is Pd or Ag, preferably Pd. M ² is Si, Ti or Zr, but is preferably Ti. Thereby, the composite metal oxide hydrate having a high plating precipitation ability is obtained.

As the composite metal oxide hydrate, for example _{PdSiO 3, Ag 2 SiO 3,} PdTiO 3, Ag 2 TiO 3, PdZrO 3 and Ag ₂ can be hydrates, such as TiO ₃ is exemplified.

  The above-mentioned mixed metal oxide hydrates are obtained by heating each corresponding metal salt, such as hydrochloride, sulfate, nitrate, halide, oxyhalide, hydrate of the corresponding metal oxide, and the like. And obtained by using a hydrolysis method or the like.

As the composite metal oxide, those represented by M ¹ _X · M ² O ₂ (M ¹ , M ² and X have the same meanings as those in the above formula (I)) are preferably used.

  The average particle size of the composite metal oxide and composite metal oxide hydrate used for the electroless plating pretreatment agent is preferably 0.01 to 10 μm, particularly 0.05 to 3 μm. Thereby, it can be set as the composite metal oxide which has the high dispersibility and catalyst activity in which aggregation was suppressed, and the said composite metal oxide hydrate.

  In the present invention, the average particle size of the composite metal oxide and the composite metal oxide hydrate is 100 times the magnification of the composite metal oxide and / or the composite metal oxide hydrate using an electron microscope (preferably a transmission electron microscope). The number average value obtained by observing at a magnification of about 10,000 times and obtaining the area equivalent circle diameter of at least 100 particles.

  The content of the composite metal oxide and / or the composite metal oxide hydrate is preferably 10 to 60 parts by mass, more preferably 10 to 40 parts by mass with respect to 100 parts by mass of the synthetic resin. If the content is less than 10 parts by mass, sufficient plating deposition ability may not be obtained, and if it exceeds 60 parts by mass, streaks and fogging based on aggregation of these composite metal oxides may be formed.

  By including a synthetic resin, the electroless plating pretreatment agent can improve the adhesion between the transparent substrate and the conductive layer, the pretreatment layer becomes difficult to peel off, and the conductive layer can be formed more accurately. It becomes possible.

  The synthetic resin is not particularly limited as long as it can secure adhesion with the transparent substrate and the conductive layer. Preferable examples include acrylic resin, polyester resin, polyurethane resin, vinyl chloride resin, and ethylene vinyl acetate copolymer resin. By using these, high adhesiveness with the transparent substrate and the conductive layer can be obtained, and the conductive layer can be accurately formed on the pretreatment layer. These synthetic resins may be used alone or in combination of two or more.

  Examples of the acrylic resin include alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, and hexyl acrylate, and alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, and hexyl methacrylate. Although homopolymers and copolymers of esters can be used, homopolymers and copolymers such as methyl methacrylate, ethyl methacrylate or butyl methacrylate are particularly preferred.

  Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and 2,6-polyethylene naphthalate.

  Examples of the polyurethane resin include a polyester urethane resin, a polyether urethane resin, and a polycarbonate urethane resin. Of these, polyester urethane resins are preferred.

  As said polyurethane resin, the polyester-type urethane resin which consists of a reaction product of a polyester-type polyol and a polyisocyanate compound can be used, for example. The average molecular weight of the polyester urethane resin is generally 10,000 to 500,000.

  Examples of the polyester polyol include a condensed polyester diol obtained by reacting a low molecular diol with a dicarboxylic acid, a polylactone diol obtained by ring-opening polymerization of a lactone, a polycarbonate diol, and the like. Examples of low molecular weight diols include diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and butylene glycol, triols such as trimethylolpropane, trimethylolethane, hexanetriol, and glycerin, and hexaols such as sorbitol. Can do. As the dicarboxylic acid, succinic acid, adipic acid, sebacic acid, glutaric acid, azelaic acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, terephthalic acid, isophthalic acid and other aromatic dicarboxylic acids, etc. are used alone or Used in two or more. Moreover, (epsilon) -caprolactone etc. are used for the said lactone.

  Examples of polyester polyols include polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polyneopentyl adipate, polyethylene butylene adipate, polybutylene hexabutylene adipate, polydiethylene adipate, poly (polytetramethylene ether) adipate, polyethylene Examples thereof include azeate, polyethylene sebacate, polybutylene azate, polybutylene sebacate, polyhexamethylene carbonate diol, and the like. These may be used alone or in combination of two or more.

  Examples of the polyisocyanate compound include aromatic diisocyanates (for example, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 1,5-naphthalene diisocyanate, n-isocyanate phenylsulfonyl isocyanate, m- or p-isocyanate). An aliphatic diisocyanate (eg, 1,6-hexamethylene diisocyanate); an alicyclic diisocyanate (eg, isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, etc.), or alternatively These adducts or multimers of various isocyanates are used alone or in combination of two or more.

  The use ratio of the polyester-based polyol and the polyisocyanate compound is not particularly limited. Usually, the polyester-based polyol: polyisocyanate compound = 1: a compound to be used within a range of about 0.01 to 0.5 (molar ratio). What is necessary is just to determine suitably according to the kind etc. of.

  When using a polyester urethane resin, the electroless plating pretreatment agent may further include a polyisocyanate curing agent. The polyisocyanate compound described above is used as the polyisocyanate curing agent. The content of the curing agent is preferably 0.1 to 5 parts by mass, more preferably 0.1 to 1.0 part by mass with respect to 100 parts by mass of the polyester urethane resin.

  The vinyl chloride resin is a homopolymer resin that is a conventionally known homopolymer of vinyl chloride, or various conventionally known copolymer resins, and is not particularly limited. As the copolymer resin, a conventionally known copolymer resin can be used, such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl propionate copolymer resin such as vinyl chloride and vinyl esters, vinyl chloride-butyl acrylate copolymer. Resins, copolymer resins of vinyl chloride and acrylates such as vinyl chloride-diethylhexyl acrylate copolymer resin, copolymer resins of vinyl chloride and olefins such as vinyl chloride-ethylene copolymer resin, vinyl chloride-propylene copolymer resin, And vinyl chloride-acrylonitrile polymer resin. In particular, it is preferable to use a vinyl chloride single resin, an ethylene-vinyl chloride copolymer resin, a vinyl acetate-vinyl chloride copolymer resin, or the like.

  As the synthetic resin, one having a functional group containing active hydrogen at the molecular end is preferable because high adhesion can be obtained. The functional group containing active hydrogen is not particularly limited as long as it has active hydrogen, primary amino group, secondary amino group, imino group, amide group, hydrazide group, amidino group, hydroxyl group, hydroperoxy Groups, carboxyl groups, formyl groups, carbamoyl groups, sulfonic acid groups, sulfinic acid groups, sulfenic acid groups, thiol groups, thioformyl groups, pyrrolyl groups, imidazolyl groups, piperidyl groups, indazolyl groups, carbazolyl groups, and the like. A primary amino group, secondary amino group, imino group, amide group, imide group, hydroxyl group, formyl group, carboxyl group, sulfonic acid group or thiol group is preferred. In particular, a primary amino group, a secondary amino group, an amide group or a hydroxyl group is preferable. These groups may be substituted with a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms. Of these, a hydroxyl group, a carbonyl group, and an amino group are preferable.

  The content of the synthetic resin in the electroless plating pretreatment agent is preferably 40 to 90% by mass, particularly 60 to 80% by mass, based on the total amount of the electroless plating pretreatment agent. Thereby, a pretreatment layer having high adhesion can be formed.

  Moreover, the electroless plating pretreatment agent may further contain inorganic fine particles. By containing the inorganic fine particles, it is possible to improve printing accuracy and to form a conductive layer with higher accuracy. Preferred inorganic fine particles include silica, calcium carbonate, alumina, talc, mica, glass flake, metal whisker, ceramic whisker, calcium sulfate whisker, smectite and the like. These may be used alone or in combination of two or more.

  The average particle diameter of the inorganic fine particles is preferably 0.01 to 5 μm, particularly preferably 0.1 to 3 μm. If the average particle size of the inorganic fine particles is less than 0.01 μm, the addition of the inorganic fine particles may not improve the printing accuracy as desired, and if it exceeds 5 μm, streaks and fog may be likely to occur. is there.

  The content of the inorganic fine particles in the electroless plating pretreatment agent is preferably 0.01 to 10 parts by mass, particularly 1 to 5 parts by mass with respect to 100 parts by mass of the synthetic resin. Thereby, it can be set as the pretreatment agent with high printing appropriateness.

  The electroless plating pretreatment agent may further contain a thixotropic agent. According to the thixotropic agent, it is possible to improve the printing accuracy by adjusting the fluidity of the pretreatment agent, and it is possible to form a conductive layer with higher accuracy. Any conventionally known thixotropic agent can be used. Preferably, amide wax, hydrogenated castor oil, beeswax, carnauba wax, stearamide, hydroxystearic acid ethylene bisamide and the like can be used.

  The content of the thixotropic agent in the electroless plating pretreatment agent is preferably 0.1 to 10 parts by mass, particularly 1 to 5 parts by mass with respect to 100 parts by mass of the synthetic resin. Thereby, it can be set as the pretreatment agent with high printing appropriateness.

  The electroless plating pretreatment agent of the present invention may further contain a black colorant. Thereby, with the improvement of a printing precision, the glare-proof effect at the time of seeing from the transparent substrate side can be provided in the light transmissive electromagnetic wave shielding material obtained.

  Preferred black colorants include carbon black, titanium black, black iron oxide, graphite, and activated carbon. These may be used individually by 1 type and may be used in mixture of 2 or more types. Of these, carbon black is preferable. Examples of carbon black include acetylene black, channel black, and furnace black. The average particle size of carbon black is preferably 0.1 to 1,000 nm, particularly preferably 5 to 500 nm.

  The content of the black colorant in the electroless plating pretreatment agent is preferably 0.1 to 10 parts by mass, particularly 1 to 5 parts by mass with respect to 100 parts by mass of the synthetic resin. This makes it possible to accurately form a pretreatment layer having an antiglare effect.

  When using a black colorant, it is preferable to prepare the electroless plating pretreatment agent using a commercially available black ink. Examples of such black ink include SS8911 manufactured by Toyo Ink Manufacturing Co., Ltd., EXG-3590 manufactured by Jujo Chemical Co., Ltd., and NT Hiramic-795R Black manufactured by Dainichi Seika Kogyo Co., Ltd. For example, in the case of SS8911 manufactured by Toyo Ink Manufacturing Co., Ltd., the solvent further contains vinyl chloride and acrylic resin in addition to carbon black. Therefore, if it is an above-mentioned commercial item, preparation of the electroless-plating pretreatment agent containing a synthetic resin and a black coloring agent can be performed easily.

  Moreover, the electroless plating pretreatment agent may contain an appropriate solvent. Examples of the solvent include water, methyl alcohol, ethyl alcohol, 2-propanol, acetone, toluene, ethylene glycol, polyethylene glycol, dimethylformamide, dimethyl sulfoxide, dioxane and the like. These may be used singly or in combination of two or more.

  The electroless plating pretreatment agent may further contain various additives such as extender pigments and surfactants as necessary.

  In the method of the present invention, for example, the above-described electroless plating pretreatment agent is printed in a mesh shape by intaglio printing having a specific mesh pattern on the transparent substrate, whereby a mesh-shaped pretreatment layer is formed on the transparent substrate. Form. Thereby, a pretreatment layer having a desired fine pattern can be formed by a simple method.

  The viscosity of the electroless plating pretreatment agent is preferably 500 to 5000 cps, more preferably 1000 to 25 ° C in order to obtain a pretreatment layer having a fine line width and a gap (pitch) without disconnection by printing. 3000 cps is preferable.

  Thus, after printing the electroless plating pretreatment agent, it is preferably dried by heating at 80 to 160 ° C, more preferably 90 to 130 ° C. If the drying temperature is less than 80 ° C., the evaporation rate of the solvent is slow, and there is a possibility that sufficient film-forming properties may not be obtained. The drying time for heat drying after coating is preferably 5 seconds to 5 minutes.

  The thickness of the pretreatment layer is generally 0.01 to 5 μm, preferably 0.1 to 2 μm. Thereby, the high adhesiveness with a transparent substrate and a conductive layer is securable.

  In the method of the present invention, after the step of forming the mesh-shaped pretreatment layer on the transparent substrate as described above, the pretreatment layer 42 is subjected to the reduction treatment before the step of forming the mesh-shaped metal conductive layer. Preferably it is done. By performing the reduction treatment, the metal species contained in the composite metal oxide and the composite metal oxide hydrate which are electroless plating catalysts contained in the pretreatment layer 42 are reduced, and only the metal species which are active components are in the form of ultrafine particles. Can be deposited uniformly. Since the metal species thus reduced and precipitated have high catalytic activity and are stable, the adhesion between the pretreatment layer 42 and the transparent substrate and the deposition rate of electroless plating are improved, and further, the composite metal oxidation is performed. It becomes possible to reduce the usage-amount of a thing and a composite metal oxide hydrate.

  The reduction treatment is not particularly limited as long as it is a method capable of reducing and metallizing the composite metal oxide and the composite metal oxide hydrate contained in the pretreatment layer. For example, (i) a liquid phase reduction method in which the transparent substrate on which the pretreatment layer is formed is treated with a solution containing a reducing agent, and (ii) the transparent substrate on which the pretreatment layer is formed is treated with a reducing gas. It is preferable to use a vapor-phase reduction method or the like in contact with.

  As a method of processing using a solution containing a reducing agent in a liquid phase reduction method, for example, a method of immersing a transparent substrate on which a pretreatment layer is formed in a solution containing a reducing agent, a pretreatment layer of a transparent substrate is formed. A method of spraying a solution containing a reducing agent on the surface can be used.

The solution containing a reducing agent is prepared by dispersing or dissolving a predetermined reducing agent in a solvent such as water. The reducing agent is not particularly limited, but formamide, dimethylformamide, diethylformamide, dimethylacetamide, dimethylacrylamide, sodium borohydride, potassium borohydride, glucose, aminoborane, dimethylamineborane (DMAB), trimethylamineborane (TMAB) Hydrazine, diethylamine borane, formaldehyde, glyoxylic acid, imidazole, ascorbic acid, hydroxylamine, hydroxylamine sulfate, hydroxylamine hydrochloride, hypophosphite, sodium hypophosphite and other hypophosphites, hydroxylamine sulfate, sulfite Examples thereof include sulfites such as sodium, hydrosulfite (Na ₂ S ₂ O ₄ : also referred to as sodium dithionite), and the like. When the same reducing agent as that contained in the electroless plating bath used in the subsequent step is used as the reducing agent, electroless plating can be performed without washing the transparent substrate after the reduction treatment. There is little risk of changing the composition of the electroplating bath.

  As the reducing agent, aminoborane, dimethylamine borane, sodium hypophosphite, hydroxylamine sulfate, hydrosulfite, and formalin are preferably used because high reducibility can be obtained.

  The content of the reducing agent in the solution containing the reducing agent is preferably 0.01 to 200 g / L, particularly preferably 0.1 to 100 g / L. If the concentration of the reducing agent is too low, it may take a long time to sufficiently perform the reduction treatment, and if the concentration of the reducing agent is too high, the deposited plating catalyst may fall off.

  As a method of processing using a solution containing a reducing agent in the liquid phase reduction method, since the high reducibility of the composite metal oxide and the composite metal oxide hydrate contained in the pretreatment layer is obtained, the pretreatment layer It is preferable to use a method of immersing the transparent substrate on which is formed in a solution containing a reducing agent.

  When the transparent substrate is immersed, the temperature of the solution containing the reducing agent is preferably 20 to 90 ° C, particularly 40 to 80 ° C. Further, the immersion time may be at least 1 minute or more, preferably about 1 to 10 minutes.

  On the other hand, when the reduction treatment is performed using the gas phase reduction method, the reducing gas is not particularly limited as long as it is a reducing gas such as hydrogen gas or diborane gas. What is necessary is just to determine suitably the reaction temperature and reaction time at the time of the reduction process using reducing gas according to the kind etc. of reducing gas to be used.

  Next, in the method of the present invention, a step of forming a mesh-like metal conductive layer is performed by performing electroless plating on the pretreatment layer obtained as described above. By performing the electroless plating treatment, fine metal particles are deposited and formed as a dense continuous film, and a metal conductive layer can be selectively obtained only on the pretreatment layer.

  The plating metal can be used as long as it is conductive and can be plated, and may be a single metal, an alloy, a conductive metal oxide, etc. It may be made of fine fine particles.

  As a plating metal in electroless plating, aluminum, nickel, indium, chromium, gold, vanadium, tin, cadmium, silver, platinum, copper, titanium, cobalt, lead, or the like can be used. In particular, silver, copper, or aluminum is preferably used because a conductive layer with high electromagnetic shielding properties can be obtained. The conductive layer formed using these plated metals is excellent in adhesion to the pretreatment layer and is suitable for achieving both light transmittance and electromagnetic shielding properties.

  Electroless plating can be performed at room temperature or under heating according to a conventional method using an electroless plating bath. That is, the plating substrate is immersed in a bath containing a plating solution containing a plating metal salt, a chelating agent, a pH adjuster, a reducing agent, etc. as a basic composition, or a component plating solution is added separately from two or more solutions What is necessary is just to select suitably, such as performing a plating process by a system.

  As an example of electroless plating, when forming a conductive layer made of Cu, a water-soluble copper salt such as copper sulfate 1 to 100 g / L, particularly 5 to 50 g / L, a reducing agent such as formaldehyde 0.5 to 10 g. / L, especially 1 to 5 g / L, containing 20 to 100 g / L, particularly 30 to 70 g / L of a complexing agent such as EDTA, and adjusted to pH 12 to 13.5, particularly 12.5 to 13 A method of immersing a transparent substrate having a treatment layer and an anchor coat layer at 50 to 90 ° C. for 30 seconds to 60 minutes can be employed.

  When performing electroless plating, the substrate to be plated may be rocked and rotated, or the vicinity thereof may be agitated with air.

  The line width of the mesh-like (lattice-like) metal conductive layer is generally 20 μm or less, preferably 5 to 15 μm, particularly 5 to 12 μm. The line pitch is preferably 200 μm or less. Further, the aperture ratio is preferably 75 to 95%, particularly 80 to 95%.

  The shape of the opening surrounded by the line of the conductive layer can be any shape such as a circle, an ellipse, and a square (quadrangle, hexagon), but is generally a square, and particularly preferably a square.

  In the method (A), a metal plating layer may be formed by performing electroplating (described later) on the mesh-like conductive layer. Further, the metal plating layer may be subjected to blackening treatment (described later), and for example, oxidation treatment of a metal film, black plating of a chromium alloy, application of black or dark color ink, or the like can be performed.

  Next, the manufacturing method of the electromagnetic shielding light transmission window material of the present invention (B) will be described with reference to the drawings.

  FIG. 7 shows a schematic diagram for explaining a method (B) for producing an electromagnetic wave shielding light-transmitting window material suitable for the present invention. As shown in (B1) and (B2), an electroless plating pretreatment agent containing a mixture or reaction product of a silane coupling agent and an azole compound and a noble metal compound on a transparent substrate 71 such as a transparent film, According to the method of the present invention, printing is performed in a mesh shape, and a mesh-shaped pretreatment layer 72 is formed on the transparent substrate 71. Then, by performing electroless plating, a mesh-like metal conductive layer 73 made of a conductive material such as metal is formed on the pretreatment layer 72.

  In the above method, the electroless plating pretreatment agent is printed on the transparent substrate 61 by intaglio printing having an intaglio surface having a specific shape corresponding to the mesh shape with varying line width of the present invention. The pretreatment agent can be formed in the shape of the dimensions, and therefore, a fine mesh-like metal conductive layer 63 having a dimension almost as designed and a small line width can be formed. In addition, the electroless plating pretreatment agent has a silane coupling agent, an azole compound, and a noble metal compound dispersed at the atomic level in the pretreatment layer, so that a fine pattern without streaking or fogging is formed. The mesh-shaped pretreatment layer can be formed with high accuracy. By performing an electroless plating process on such a mesh-shaped pretreatment layer, it is possible to form a mesh-shaped metal conductive layer with almost no moiré and varying line width.

  In the method (B) of the present invention, the silane coupling agent used as a pretreatment agent for electroless plating preferably has a functional group having a metal-capturing ability in one molecule. Thereby, it becomes possible to set it as the electronic state and orientation state which express effectively the activity of the noble metal compound which is an electroless-plating catalyst, and high adhesiveness with a to-be-plated material is obtained.

  An example of the silane coupling agent is an epoxy group-containing silane compound. Examples of the epoxy group-containing silane compound include γ-glycidoxypropyltrialkoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, Examples thereof include 3-glycidoxypropylmethyldiethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. These may be used alone or in combination of two or more. In particular, γ-glycidoxypropyltrialkoxysilane is preferable because the obtained pretreatment layer exhibits high adhesion to the transparent substrate and the conductive layer.

  Next, as the azole compound used for the electroless plating pretreatment agent, imidazole, oxazole, thiazole, selenazole, pyrazole, isoxazole, isothiazole, triazole, oxadiazole, thiadiazole, tetrazole, oxatriazole, thiatriazole, Examples thereof include bendazole, indazole, benzimidazole, benzotriazole, and indazole. Although not limited to these, imidazole is particularly preferable because it is excellent in reactivity with a functional group such as an epoxy group of the silane coupling agent and a noble metal compound.

  In the electroless plating pretreatment agent, the silane coupling agent and the azole compound may be simply mixed, but may be reacted in advance to form a reaction product. As a result, the precious metal compound can be more highly dispersed at the atomic level in the pretreatment layer, and the light transmittance of the resulting pretreatment layer can be improved.

  In order to react the silane coupling agent and the azole compound, for example, 0.1 to 10 mol of the silane coupling agent is mixed with respect to 1 mol of the azole compound at 80 to 200 ° C. for 5 minutes to 2 hours. It is preferable to react. In that case, although a solvent is generally unnecessary, in addition to water, an organic solvent such as chloroform, dioxanemethanol or ethanol may be used. An electroless plating pretreatment agent is obtained by mixing a noble metal compound with the reaction product of the silane coupling agent and the azole compound thus obtained.

  Next, the noble metal compound used for the electroless plating pretreatment agent exhibits a catalytic effect capable of selectively depositing and growing a metal such as copper or aluminum in the electroless plating treatment. For example, it is preferable to use a compound containing a metal atom such as palladium, silver, platinum, and gold because high catalytic activity can be obtained. As such a compound, an ammine complex such as a chloride, hydroxide, oxide, sulfate or ammonium salt of the above metal atom is used, and a palladium compound, particularly palladium chloride, is particularly preferable.

  The electroless plating pretreatment agent preferably contains a noble metal compound in an amount of 0.001 to 50 mol%, more preferably 0.1 to 20 mol% with respect to the azole compound and the silane coupling agent. If the concentration of the noble metal compound is less than 0.001 mol%, sufficient catalytic activity may not be obtained and a conductive layer having a desired thickness may not be formed. If the concentration exceeds 50 mol%, the increase in the amount added is commensurate. There is a risk that the catalytic effect of the noble metal compound cannot be obtained.

  Moreover, the electroless plating pretreatment agent may contain an appropriate solvent. Examples of the solvent include water, methyl alcohol, ethyl alcohol, 2-propanol, acetone, toluene, ethylene glycol, polyethylene glycol, dimethylformamide, dimethyl sulfoxide, dioxane and the like. These may be used individually by 1 type and may be used in mixture of 2 or more types.

  The electroless plating pretreatment agent may further contain various additives such as extender pigments, surfactants, and colorants as necessary.

  The viscosity of the electroless plating pretreatment agent (B) is preferably 500 to 5000 cps, more preferably 1000 to 25 ° C in order to obtain a pretreatment layer having a fine line width and a gap (pitch) by printing. It is good to set it as 3000 cps.

  Intaglio printing such as gravure printing is used to print the electroless plating pretreatment agent. The printing speed is preferably 5 to 50 m / min.

  After printing the electroless plating pretreatment agent in this manner, it is preferably dried by heating at 80 to 160 ° C., more preferably 90 to 130 ° C. If the drying temperature is less than 80 ° C., the evaporation rate of the solvent is slow and there is a possibility that sufficient film formability may not be obtained, and if it exceeds 160 ° C., thermal decomposition of the compound may occur. The drying time for heat drying after coating is preferably 5 seconds to 5 minutes.

  In the method (B) of the present invention, an electroless plating treatment is performed on the pretreatment layer in the same manner as the method (A) of the present invention. An electroplating treatment may be further performed on the obtained mesh-like metal conductive layer to form a metal plating layer. Further, the metal plating layer may be subjected to blackening treatment, for example, oxidation treatment of a metal film, black plating of a chromium alloy or the like, application of black or dark color ink, or the like.

  The line width of the mesh-shaped metal conductive layer is generally 20 μm or less, preferably 5 to 15 μm, particularly 5 to 12 μm. The line pitch is preferably 200 μm or less. Further, the aperture ratio is preferably 75 to 95%, particularly 80 to 95%.

  The shape of the opening surrounded by the line of the conductive layer can be any shape such as a circle, an ellipse, and a square (quadrangle, hexagon), but is generally a square, and particularly preferably a square.

  The method for producing the electromagnetic shielding light transmitting window material of the present invention (C) will be described with reference to the drawings.

  FIG. 8 is a schematic view for explaining a method (C) for forming a light-transmitting electromagnetic wave shielding window material suitable for the present invention. As shown in (C1), a conductive ink 83 containing conductive particles and a binder resin is printed on the transparent substrate 81 in a mesh shape according to the method of the present invention, thereby forming a mesh-like conductive layer 83.

  The conductive ink is printed by, for example, intaglio printing having a specific shape of the intaglio surface corresponding to the mesh shape of the present invention, and the mesh-like conductive layer can be printed in a shape having a size almost as designed. For this reason, it is possible to accurately form a mesh-like conductive layer in which the generation of streaks and fog, almost no moire, and the line width varies.

  The conductive particles used in the conductive ink include metals, alloys such as aluminum, nickel, indium, chromium, gold, vanadium, tin, cadmium, silver, platinum, copper, titanium, cobalt, lead; or ITO, oxidation Indium, tin oxide, zinc oxide, indium oxide-tin oxide (ITO, so-called indium-doped tin oxide), tin oxide-antimony oxide (ATO, so-called antimony-doped tin oxide), zinc oxide-aluminum oxide (ZAO; so-called aluminum-doped oxide) And conductive oxides such as zinc). These may be used alone or in combination of two or more.

  Especially, as said electroconductive particle, silver, copper, gold | metal | money, nickel, indium, and tin are mentioned preferably. With these conductive particles, the conductivity of the resulting mesh-like conductive layer can be improved.

  The average particle diameter of the conductive particles is preferably 10 nm to 10 μm, particularly preferably 10 nm to 5 μm.

  The content of the conductive particles in the conductive ink is preferably 400 to 1000 parts by mass, particularly 400 to 800 parts by mass with respect to 100 parts by mass of the binder resin. Thereby, the conductive layer excellent in the contact property of electroconductive particles can be formed.

  Examples of the binder resin used for the conductive ink include acrylic resin, polyester resin, epoxy resin, urethane resin, phenol resin, maleic acid resin, melamine resin, urea resin, polyimide resin, and silicon-containing resin. Furthermore, it is preferable that it is a thermosetting resin among these resins.

  The conductive ink may further contain a solvent in order to adjust to an appropriate viscosity. Solvents include alcohols such as hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, stearyl alcohol, seryl alcohol, cyclohexanol, terpineol; ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol Examples include alkyl ethers such as monophenyl ether, diethylene glycol, diethylene glycol monobutyl ether (butyl carbitol), cellosolve acetate, butyl cellosolve acetate, carbitol acetate, and butyl carbitol acetate.

  The conductive ink may further contain a black colorant. Thereby, with the improvement of a printing precision, the glare-proof effect at the time of seeing from the transparent substrate side can be provided in the electromagnetic wave shielding light transmission window material obtained.

  As the black colorant, it is preferable to use carbon black, titanium black, black iron oxide, graphite, activated carbon, and the like. These may be used individually by 1 type and may be used in mixture of 2 or more types. Of these, carbon black is preferable. Examples of carbon black include acetylene black, channel black, and furnace black. The average particle size of carbon black is preferably 0.1 to 1,000 nm, particularly preferably 5 to 500 nm.

  The content of the black colorant in the conductive ink is preferably 0.1 to 10 parts by mass, particularly 1 to 5 parts by mass with respect to 100 parts by mass of the binder resin.

  The conductive ink may further contain a conventionally known auxiliary agent such as a dispersant such as a surfactant, a plasticizer, an antifoaming agent, and a curing agent.

  When printing the above-mentioned conductive ink in a mesh form on a transparent substrate, the viscosity of the conductive ink is to suppress the occurrence of disconnection and to have a fine line width and gap (pitch) by printing. At 25 ° C., it is preferably 100 to 10000 cps, more preferably 500 to 5000 cps.

  The line width of the mesh-like conductive layer is generally 20 μm or less, preferably 5 to 15 μm, particularly 5 to 12 μm. The line pitch is preferably 200 μm or less. Further, the aperture ratio is preferably 75 to 95%, particularly 80 to 95%. The aperture ratio is obtained by calculation from the line width of the mesh and the number of lines existing in 1 inch width.

  The shape of the opening surrounded by the line of the conductive layer can be any shape such as a circle, an ellipse, and a square (quadrangle, hexagon), but is generally a square, and particularly preferably a square.

  On the mesh-like (metal) conductive layer obtained by the method of the present invention (including the above (A) to (C)), an electroplating treatment (in the case of (C), electroless plating treatment or electroplating) is further performed. And a metal plating layer may be formed on the conductive layer. Further, the antiglare layer may be formed on the plated layer, or the following blackening treatment may be performed.

  The material used for the plating process is not particularly limited as long as the metal plating layer has an excellent electromagnetic wave shielding effect. For example, metals such as copper, nickel, chromium, zinc, tin, silver, and gold are used. Is mentioned. These may be used individually by 1 type and may be used as 2 or more types of alloys.

  0.1-10 micrometers is preferable and, as for the thickness of a metal plating layer, 2-5 micrometers is more preferable. When the thickness is less than 0.1 μm, sufficient electromagnetic wave shielding effect may not be provided. On the other hand, when the thickness exceeds 10 μm, the plating spreads in the width direction when forming the plating layer, so that the line width is large. Therefore, the aperture ratio of the conductive layer may be lowered.

  The surface resistivity in the metal plating layer is preferably 3Ω / □ or less, and more preferably 1Ω / □ or less. When the surface resistivity of the plating layer exceeds 3Ω / □, the conductivity may be insufficient and the electromagnetic shielding effect may be insufficient.

  After forming the metal plating layer, the antiglare property may be imparted. When this anti-glare treatment is performed, a blackening treatment may be performed on the surface of the mesh-like conductive layer. For example, oxidation treatment of a conductive layer or a plating layer, sulfidation treatment, black plating of a chromium alloy, application of black or dark color ink, and the like can be performed.

  The blackening treatment is preferably performed by oxidizing or sulfiding a metal of the conductive layer or the plating layer. In particular, the oxidation treatment can obtain a more excellent antiglare effect, and is also preferable from the viewpoint of simplicity of waste liquid treatment and environmental safety.

  When oxidation treatment is performed as a blackening treatment, the blackening treatment solution is generally a mixed aqueous solution of hypochlorite and sodium hydroxide, a mixed aqueous solution of chlorite and sodium hydroxide, peroxodisulfuric acid and water. It is possible to use a mixed aqueous solution of sodium oxide, and in particular, from the economical point of view, a mixed aqueous solution of hypochlorite and sodium hydroxide or a mixed aqueous solution of chlorite and sodium hydroxide is used. It is preferable.

  When performing a sulfurization treatment as a blackening treatment, it is generally possible to use an aqueous solution such as potassium sulfide, barium sulfide and ammonium sulfide as the blackening treatment solution, preferably potassium sulfide and ammonium sulfide. Particularly, ammonium sulfide is preferably used because it can be used at a low temperature.

  The thickness of the blackening treatment layer is not particularly limited, but is generally 0.01 to 1 μm, preferably 0.01 to 0.5 μm. If the thickness is less than 0.01 μm, the antiglare effect of light may not be sufficient, and if it exceeds 1 μm, the apparent aperture ratio when viewed from the perspective may be reduced.

  In the method of the present invention, the transparent substrate to which the pretreatment agent or the conductive ink is applied is not particularly limited as long as it has transparency and flexibility and can withstand the subsequent treatment. Examples of the material of the transparent substrate include glass, polyester (eg, polyethylene terephthalate, (PET), polybutylene terephthalate), acrylic resin (eg, polymethyl methacrylate (PMMA)), polycarbonate (PC), polystyrene, cellulose triacetate, Polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane, etc. PET, PC, and PMMA, which are less transparent due to processing (heating, solvent, bending) and are highly transparent, are preferable. The transparent substrate is used as a sheet, film, or plate made of these materials.

  The thickness of the transparent substrate is not particularly limited, but it is preferably as thin as possible from the viewpoint of maintaining the light transmittance of the light-transmitting electromagnetic wave shielding material. Usually, depending on the form at the time of use and the required mechanical strength The thickness is appropriately set in the range of 0.05 to 5 mm.

  Using a long plastic film as the transparent substrate of the present invention, in a roll-to-roll system, while continuously transporting the long plastic film, printing of the pretreatment layer, drying, electroless plating treatment, etc. It is preferable to obtain a light-transmitting electromagnetic wave shielding material simply by continuously or by conducting conductive ink printing, drying, and optionally performing plating treatment or the like.

  The light-transmitting electromagnetic wave shielding material thus obtained may further have a hard coat layer, an antireflection layer, a color tone correction filter layer, a near-infrared absorbing layer and the like in addition to the adhesive layer. The order of stacking these layers is determined according to the purpose. Further, the display filter may be provided with an electrode for connecting to the ground electrode of the PDP main body in order to enhance the electromagnetic wave shielding function.

  As a preferable light transmissive electromagnetic wave shielding material, for example, a hard coating layer and an antireflection layer such as a low refractive index layer are provided on the surface of the obtained mesh-like conductive layer, and a near infrared absorption layer is provided on the back surface. Or with a near-infrared absorbing layer provided directly on the surface of the mesh-like conductive layer via an adhesive layer or an antireflection layer such as a hard coat layer and a low refractive index layer on the back surface. Can be mentioned.

  The light-transmitting electromagnetic wave shielding material of the present invention is used for applications requiring light transmission, for example, display surfaces of display devices such as LCDs, PDPs, and CRTs of various electric devices that generate electromagnetic waves, or transparent glass for facilities and houses. It is suitably applied to surfaces and transparent panel surfaces. Since the light transmissive electromagnetic wave shielding material of the present invention has high light transmissive property and electromagnetic wave shielding property, it is suitably used for the display filter of the above-described display device, particularly the PDP filter.

  Hereinafter, the present invention will be described with reference to examples. The present invention is not limited by the following examples.

[Example 1]
(1) Preparation of pretreatment agent Composite metal oxide hydrate particles (PdTiO ₃ .6H ₂ O, average particle size 0.5 μm) are combined in a polyester urethane resin solution with 100 parts by mass of polyester urethane resin. A pretreatment agent (viscosity: 2000 cps, 25 ° C.) was prepared by blending 30 parts by mass of metal oxide hydrate particles and 10 parts by mass of a thixotropic agent (AEROSIL200).

  The polyester-based urethane resin solution used had a solid content concentration of 10% by mass including a polyester resin (Toyobo Co., Ltd., Byron 200, Tg: 10 ° C.).

2. Next, the pretreatment agent is patterned on a PET film (thickness: 100 μm) by gravure printing, and then dried at 120 ° C. for 5 minutes to form a mesh on the PET film. A pretreatment layer was formed. The resulting mesh-shaped pretreatment layer had a line-to-line distance (distance between the centers of two adjacent lines of the mesh) of 254 μm, an average line width of 20 μm, an aperture ratio of 85%, and a thickness of 0.5 μm. It was.

The mesh shape of the mesh-shaped pretreatment layer has the following configuration:
As a line in one of the two directions of the mesh,
The maximum value of the line width (W _max) and the difference (Rz) is 2μm to the minimum value (W _min) adjacent thereto, the maximum value of the line width (W _max), maximum value adjacent thereto and (W _max) The area where the distance (S) is 10 μm (one side of each mesh; the starting position is the minimum value), and the next side beyond the mesh intersection, the line width maximum value (W _max ) and the adjacent minimum value A region (1 side of each mesh) in which the difference (Rz) from (W _min ) is 2 μm and the distance (S) between the maximum value (W _max ) of the line width and the adjacent maximum value (W _max ) is 20 μm And the lines formed by repeating this combination are arranged in parallel while shifting one side as shown in FIG. 4;
As a line in the other direction of the two directions of the mesh,
The maximum value of the line width (W _max) and the difference (Rz) is 2μm to the minimum value (W _min) adjacent thereto, the maximum value of the line width (W _max), maximum value adjacent thereto and (W _max) A region with a distance (S) of 40/3 μm (one side of each mesh; the starting position is the minimum value), and the next side beyond the mesh intersection also forms a region having the same regularity, and the next mesh the following one side beyond the intersection, the difference (Rz) is 2μm in the maximum value of the line width (W _max) and minimum value adjacent thereto (W _min), the maximum value of the line width (W _max), As shown in FIG. 4, a line formed by forming a region (one side of each mesh) having a distance (S) of 20 μm from the adjacent maximum value (W _max ) and repeating the combination of these three sides. And arranged in parallel while shifting one side (shape shown in FIG. 4).

3. Next, the PET film on which the pretreatment layer obtained above was formed was immersed in a sodium hypophosphite solution (NaH ₂ PO ₂ concentration: 30 g / L) at 60 ° C. for 3 minutes. The pretreatment layer was reduced.

4). Preparation of metal conductive layer The PET film on which the pretreatment layer reduced as described above is formed is immersed in an electroless copper plating solution (Melplate CU-5100 manufactured by Meltex Co., Ltd.) at 50 ° C. for 20 minutes. An electroless copper plating treatment was performed to obtain a mesh-like metal conductive layer. The metal conductive layer had a line width of 25 μm, a line interval of 254 μm, an aperture ratio of 81%, and a thickness of 4 μm. The mesh shape of the metal conductive layer was the same as that of the mesh of the mesh-shaped pretreatment layer.

5. Blackening treatment of metal conductive layer Furthermore, the blackening treatment of the following composition was performed with respect to the PET film in which the metal conductive layer obtained above was formed.

Blackening solution composition (aqueous solution)
Sodium chlorite: 10% by mass
Sodium hydroxide: 4% by mass
Blackening conditions Bath temperature: Approx. 60 ° C
Time: 5 minutes

  By this blackening treatment, a light-transmitting electromagnetic wave shielding material in which the surface of the metal conductive layer was blackened was obtained. The thickness of the surface of the obtained light-transmitting electromagnetic wave shielding material subjected to blackening treatment was 0.5 μm on average. Other dimensions were unchanged.

[Reference Example 1]
In Example 1, a light-transmitting electromagnetic wave shielding material was produced in the same manner except that a normal straight mesh was formed as a mesh-shaped pretreatment layer.

  The obtained mesh-shaped pretreatment layer had a line interval of 254 μm, a line width of 20 μm, an aperture ratio of 85%, and a thickness of 0.5 μm. The metal conductive layer had a line width of 25 μm, a line interval of 254 μm, an aperture ratio of 81%, a thickness of 4 μm, and a blackening treatment layer having an average of 0.5 μm.

[Evaluation of light transmissive electromagnetic shielding material]
1) Moire Each electromagnetic shielding light transmitting window material is arranged on a PDP light emitting panel having a screen size of 40 inches and a pixel cell pitch of 0.42 mm × 1.26 mm, and this electromagnetic shielding light transmitting window material is made of conductive mesh. After arranging the warp yarn direction so as to coincide with the vertical direction of the panel, the electromagnetic wave shielding light transmitting window material was rotated clockwise by 0 to 45 degrees, and the frequency of occurrence of moire was measured.

◎: Moire is hardly seen ○: Moire is slightly seen ×: Moire is not frequently seen

2) Electromagnetic wave shielding property After forming the plating layer, the electromagnetic wave shielding property is measured by the KEC method and evaluated as follows.

  ○: 40 dB or more Δ: 20 dB or more and less than 40 dB

  The results are shown in Table 1.

It is a schematic sectional drawing which shows one example of the light transmissive electromagnetic wave shielding material of this invention. It is a schematic plan view which shows one example of the mesh-shaped electroconductive layer of the light transmissive electromagnetic wave shielding material of this invention. It is the elements on larger scale of the mesh-shaped electroconductive layer of FIG. It is an enlarged plan view showing an example of a wider range of the mesh-like conductive layer. It is a top view which shows the other example of the elements on larger scale of a mesh-shaped electroconductive layer. It is a schematic sectional drawing which shows a typical example of the manufacturing method of the light-transmitting electromagnetic wave shielding material of this invention. It is a schematic sectional drawing which shows another example of the manufacturing method of the light-transmitting electromagnetic wave shielding material of this invention. It is a schematic sectional drawing which shows another example of the manufacturing method of the light-transmitting electromagnetic wave shielding material of this invention.

Explanation of symbols

11, 61, 71, 81 Transparent substrate 12, 62, 72 Pretreatment agent 82 Conductive ink 13, 63, 73 Metal conductive layer

Claims (9)

Having a transparent substrate, and a mesh-like metal conductive layer provided thereon,
A light-transmitting electromagnetic wave shielding material, wherein the line width of the mesh of the metal conductive layer varies.   The light-transmitting electromagnetic wave shielding material according to claim 1, wherein the line width alternately forms a maximum value and a minimum value in at least a partial region of the mesh.   The light transmittance according to claim 2, wherein a difference between the maximum value of the line width and the adjacent minimum value in at least a part of the mesh is greater than 5% and less than 20% of the average line width of the mesh. Electromagnetic shielding material.   The distance between the maximum value of the line width and the adjacent maximum value in at least a part of the mesh is smaller than the inter-line distance (pitch) of the mesh and larger than 10% of the pitch. Light transmissive electromagnetic shielding material.   The light-transmitting electromagnetic wave shielding material according to any one of claims 1 to 3, wherein a mesh-shaped pretreatment layer is provided between the transparent substrate and the metal conductive layer. Forming a mesh-like pretreatment layer by pattern-printing an electroless plating pretreatment agent on the surface of the transparent substrate; and forming a mesh-like metal conductive layer on the pretreatment layer by an electroless plating treatment;
A method for producing a light-transmitting electromagnetic wave shielding material comprising:
The manufacturing method, wherein the mesh-shaped pretreatment layer is formed so that the line width of the mesh varies.   The manufacturing method according to claim 6, wherein the electroless plating pretreatment agent is a liquid containing a composite metal oxide and / or a composite metal oxide hydrate and a synthetic resin.   The manufacturing method according to claim 6, wherein the electroless plating pretreatment agent is a liquid containing a mixture or reaction product of a silane coupling agent and an azole compound, and a noble metal compound. In the method for producing a light-transmitting electromagnetic wave shielding material including a step of forming a mesh-like conductive layer by pattern printing a conductive ink containing metal fine particles and a binder resin on the surface of a transparent substrate,
The manufacturing method, wherein the mesh-like conductive layer is formed so that the line width of the mesh varies.

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