JP2010093040A - Light permeable electromagnetic shield material and method for manufacturing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light permeable electromagnetic shield material which has a high-precision mesh pattern conductive layer obtained easily, and also to provide a method for manufacturing the light permeable electromagnetic shield material. <P>SOLUTION: The method for manufacturing the light permeable electromagnetic shield material includes processes of: forming a mesh-like pretreatment layer on a transparent substrate by printing a nonelectrolytic plating pretreatment agent containing catalyst particles for nonelectrolytic plating on the transparent substrate like the mesh by using an intaglio printing plate which has mesh pattern; and forming a mesh-like metal conductive layer by performing nonelectrolytic plating on the pretreatment layer. An arithmetic means particle size of a secondary particle of the catalyst particles for nonelectrolytic plating, which is contained in the nonelectrolytic plating pretreatment agent, is 10% or less of a concave portion width in the mesh pattern of the intaglio printing plate and is 20% or less of a concave portion depth. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  TECHNICAL FIELD The present invention relates to a light-transmitting electromagnetic wave shielding material useful as a sticking sheet that can be used for a front filter of a plasma display panel (PDP), a building window that requires an electromagnetic wave shield such as a hospital, and the like, and a method for manufacturing the same. .

  In recent years, with the spread of OA equipment, communication equipment, etc., there is a concern about the influence on the human body caused by electromagnetic waves generated from these equipment. In addition, there is a case where a precision device malfunctions due to electromagnetic waves of a mobile phone or the like, and electromagnetic waves are regarded as a problem from this point.

  As a front filter for PDP of OA equipment, a light transmissive electromagnetic wave shielding material having an electromagnetic wave shielding property and a light transmissive property has been developed and put into practical use. Such a light-transmitting electromagnetic wave shielding material is also used as a window material for installation of precision equipment such as hospitals and laboratories in order to protect precision equipment from electromagnetic waves.

  In this light-transmitting electromagnetic wave shielding material, it is necessary to satisfy both the light transmitting property and the electromagnetic wave shielding property. For that purpose, for example, (1) a material having an electromagnetic wave shielding layer made of a conductive mesh in which a metal wire or a conductive fiber is made into a net is provided on one surface of a transparent substrate. The Electromagnetic waves are shielded by the conductive mesh portion, and light transmission is ensured by the opening.

  In addition, various types of light transmissive electromagnetic wave shielding materials have been proposed as filters for electronic displays. For example, (2) a transparent substrate provided with a transparent conductive thin film containing metallic silver, (3) a layer of copper foil or the like on the transparent substrate is etched into a net shape, and an opening is provided, (4) a transparent substrate In general, a conductive ink containing conductive powder printed on a mesh is known.

  In such an electromagnetic wave shielding layer, in order to achieve both excellent light transmittance and electromagnetic wave shielding properties, it is necessary to use a mesh-like conductive layer, to make the line width extremely thin and to make a very fine high-definition pattern. However, with the conventional light-transmitting electromagnetic wave shielding material described above, it has been difficult to achieve both light transmission and electromagnetic wave shielding sufficiently. That is, the light-transmitting electromagnetic wave shielding material (1) has a limitation in thinning, and it is difficult to obtain a fine mesh pattern, and there is a problem that the arrangement of fibers such as misalignment and bending is disturbed. In the case of the light-transmitting electromagnetic wave shielding material (2), there are problems such as insufficient electromagnetic wave shielding properties and strong reflection gloss specific to metals. The light-transmitting electromagnetic wave shielding material (3) has problems such as a long manufacturing process and high cost. Further, in the light transmissive electromagnetic wave shielding material of (4), it is difficult to obtain sufficient electromagnetic wave shielding properties. If the pattern is thickened to increase the electromagnetic shielding properties and the amount of conductive powder is increased, There are problems such as a decrease in permeability.

  However, the production of the light-transmitting electromagnetic wave shielding material (4) is performed by using an intaglio offset printing method on a transparent substrate using, for example, a conductive ink containing a conductive powder such as metal powder or carbon powder and a resin. Since it is performed using a method of forming a printed pattern, the light-transmitting electromagnetic wave shielding material of (4) has an advantage that it can be manufactured in a simple method and at a low cost without requiring an etching process. Yes.

  Therefore, as an improvement of the technique of (4), in Patent Documents 1 and 2, in order to further improve the electromagnetic wave shielding property after forming a printing pattern on a transparent substrate with a conductive ink using an intaglio offset printing method. A method of selectively forming a metal layer on the printed pattern by electroless plating or electrolytic plating is disclosed.

  Further, in Patent Document 3, pattern printing is performed with a paste containing a carrier produced by supporting the noble metal ultrafine particle catalyst on particles having a surface charge opposite to that of the noble metal ultrafine particle catalyst on a transparent substrate. A method for producing a light-transmitting electromagnetic wave shielding material is disclosed in which an electroless plating process is performed on a printed noble metal ultrafine particle catalyst to form a conductive metal layer only on a pattern printing portion.

Japanese Patent No. 3017987 Japanese Patent No. 3532146 Japanese Patent No. 336383

  However, in the light-transmitting electromagnetic wave shielding material according to Patent Documents 1 and 2 described above, it is difficult to form a fine pattern by accurately printing a conductive ink or paste. Still leaves room for improvement. Compared to this, the method of Patent Document 3 has good transparency because the electroless plating process is performed on the pattern-printed noble metal ultrafine particle catalyst to form a metal layer.

  However, even in the method of Patent Document 3, it is not easy to print a layer of a noble metal ultrafine particle catalyst in a fine pattern and form a homogeneous electroless plating layer thereon.

  Accordingly, an object of the present invention is to provide a light-transmitting electromagnetic wave shielding material having a highly accurate mesh pattern conductive layer that can be easily obtained.

  Another object of the present invention is to provide a light-transmitting electromagnetic wave shielding material that can be easily obtained, has excellent light transmittance and electromagnetic wave shielding properties, and has a highly accurate mesh pattern conductive layer.

  Furthermore, the objective of this invention is providing the manufacturing method of the light transmissive electromagnetic wave shielding material which can obtain easily the light transmissive electromagnetic wave shielding material which has a highly accurate mesh pattern.

  A high-definition mesh pattern having a width of several tens of μm or less is easily formed using an ink (pretreatment agent) for forming a layer (pretreatment layer) of catalyst particles for electroless plating such as the above-mentioned ultrafine noble metal particles. Therefore, the present inventors have conducted various studies. The following problems have been clarified by the study of the present inventors.

  In order to form a pretreatment layer for a high-definition mesh pattern, it is considered that the smaller the primary particle size of the electroless plating catalyst particles (hereinafter also referred to as catalyst particles), the more advantageous. It was found that secondary particles can be easily formed by agglomeration in the above, which inhibits the formation of a homogeneous high-definition mesh pattern pretreatment layer.

  When the particle size of the secondary particles of the catalyst particles in the pretreatment agent is large, it is difficult to print a high-definition mesh pattern sharply, and the end shape is likely to be disturbed or disconnected. Further, in the pretreatment layer of the formed mesh pattern, the active sites that are the cores of the plating are likely to increase due to the aggregation of the catalyst particles. In this case, the aggregated large active sites are scattered in the pretreatment layer. Thus, the density of catalyst nuclei in the mesh pattern (pretreatment layer) is lowered, and it is difficult to obtain a uniform plating film.

  Further, in the pretreatment agent, the secondary particles in which the catalyst particles are aggregated as described above are difficult to enter the concave portions of the printing plate at the time of printing. Therefore, the density of catalyst particle nuclei in the printed pretreatment layer is reduced, Similar to the above, it is difficult to obtain a uniform plating film.

  As a result of further studies by the present inventors, the arithmetic average particle size of the secondary particles of the catalyst particles in the pretreatment agent is set to a certain value or less with respect to the width and depth of the recesses of the intaglio printing plate, It was revealed that the density of catalyst particle nuclei in the pretreatment layer was increased and a uniform plating film could be obtained.

The present invention
A transparent substrate, a mesh-shaped pretreatment layer on the transparent substrate, a light-transmitting electromagnetic wave shielding material comprising a mesh-like metal conductive layer provided on the pretreatment layer,
Electroless plating catalyst particles in which the pretreatment layer has an arithmetic average particle diameter of secondary particles in a range of 10% or less of the line width in the mesh shape and less than or equal to the thickness of the line (that is, 100% or less of the thickness) A light-transmitting electromagnetic wave shielding material, characterized by being formed by applying a pretreatment agent containing a transparent substrate,
It is in.

  In addition, the dimension of the arithmetic average particle diameter of the secondary particle of such a catalyst particle corresponds with the dimension of the secondary particle of the catalyst particle in the pre-processing layer obtained substantially.

Below, the preferable aspect of the light transmissive electromagnetic wave shielding material of this invention is listed below.
(1) The arithmetic average particle diameter of the secondary particles is 0.5% or more of the line width of the mesh and 2% or more of the thickness of the line.
(2) The pretreatment agent contains a dispersant.
(3) The electroless plating catalyst particles are fine particles containing a noble metal.
(4) The fine particles containing a noble metal are fine particles with a noble metal supported on the surface, particularly metal oxide fine particles with a noble metal supported on the surface. Since the noble metal adheres to the surface of the fine particles, the exposed surface area of the noble metal can be increased, and electroless plating can be performed efficiently.
(5) The metal oxide fine particles are titanium oxide fine particles, particularly titanium dioxide fine particles. By using the titanium dioxide fine particles, the noble metal is supported in a stable and highly active state, so that electroless plating can be performed efficiently.
(6) The noble metal is at least one metal selected from the group consisting of palladium, silver, platinum, and gold. Palladium is preferred. Electroless plating is easily formed.
(7) The fine particles containing a noble metal in the pretreatment layer are fine particles of a noble metal-containing composite metal oxide or composite metal oxide hydrate.
(8) The composite metal oxide hydrate is represented by the 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. The composite metal oxide hydrate is PdTiO ₃ · 6 (H ₂ O).
(9) The arithmetic average particle diameter of the secondary particles of the electroless plating catalyst particles is 0.1 to 1.0 μm.
(10) The average primary particle diameter of the fine particles containing a noble metal is 0.01 to 1 μm.
(11) The layer thickness of the pretreatment layer containing fine particles containing a noble metal is 0.1 to 3 μm.
(12) The pretreatment layer includes a synthetic resin, and the synthetic resin is at least one selected from the group consisting of an acrylic resin, a polyester resin, a polyurethane resin, a vinyl chloride resin, and an ethylene vinyl acetate copolymer resin. It is a seed. According to these, high adhesiveness with a transparent substrate and a metal conductive layer can be improved.

The present invention also provides
A method for producing the light-transmitting electromagnetic wave shielding material of the present invention,
By forming an electroless plating pretreatment agent containing electroless plating catalyst particles in a mesh form on a transparent substrate using an intaglio printing plate having a mesh pattern, a mesh-like pretreatment layer is formed on the transparent substrate. And the process of
Forming a mesh-shaped metal conductive layer by performing electroless plating on the pretreatment layer;
And the arithmetic average particle size of secondary particles of the electroless plating catalyst particles contained in the pretreatment agent for electroless plating is 10% or less of the recess width and 20% of the recess depth in the mesh pattern of the intaglio printing plate A method for producing a light-transmitting electromagnetic wave shielding material, characterized by being in the following range,
There is also.

Hereinafter, preferable embodiments in the method for producing a light-transmitting electromagnetic wave shielding material of the present invention are listed below.
(1) The arithmetic average particle diameter of the secondary particles of the electroless plating catalyst particles is 1% or more of the recess width and 2% or more of the thickness of the recess depth.
(2) The pretreatment agent contains a dispersant.
(3) The plating metal by electroless plating is copper, nickel, gold, silver, platinum, palladium, tin, or cobalt.
(4) After performing electroless plating, further electrolytic plating is performed.
(5) Further, the method includes a step of blackening or blackening the metal conductive layer to form a blackened layer on at least a part of the surface of the metal conductive layer.
(6) The intaglio printing plate is a gravure printing plate.
(7) The electroless plating catalyst particles are fine particles containing a noble metal.
(8) The fine particles containing a noble metal are fine particles with a noble metal supported on the surface, particularly metal oxide fine particles with a noble metal supported on the surface.
(9) The metal oxide fine particles are titanium oxide fine particles, particularly titanium dioxide fine particles.
(10) The noble metal is at least one metal selected from the group consisting of palladium, silver, platinum, and gold.
(11) The fine particles containing a noble metal in the pretreatment layer are fine particles of a noble metal-containing composite metal oxide or composite metal oxide hydrate.
(12) The composite metal oxide hydrate is represented by the formula (I). The composite metal oxide hydrate is preferably PdTiO ₃ · 6 (H ₂ O).
(13) The electroless plating pretreatment agent includes a synthetic resin. The synthetic resin is at least one selected from the group consisting of acrylic resin, polyester resin, polyurethane resin, vinyl chloride resin, and ethylene vinyl acetate copolymer resin.
(14) The electroless plating pretreatment agent further contains a thixotropic agent.
(15) The electroless plating pretreatment agent further contains an organic solvent.
(16) A step of reducing the pretreatment layer is performed before the step of forming the mesh-shaped metal conductive layer.
(17) The reduction treatment is performed by immersing the transparent substrate on which the pretreatment layer is formed in a solution containing a reducing agent.
(18) The reducing agent is at least one selected from the group consisting of aminoborane, dimethylamine borane, sodium hypophosphite, hydroxylamine sulfate, hydrosulfite, and formalin.
(19) After performing electroless plating, further electrolytic plating is performed. Thereby, a metal conductive layer having a desired thickness can be obtained.
(20) The method further includes a step of blackening or black plating the metal conductive layer to form a blackened layer on at least a part of the surface of the metal conductive layer. Thereby, the glare-proof property can be provided to the said metal conductive layer, and visibility can be improved.

  The mesh-shaped pretreatment layer on the transparent substrate of the present invention is formed of a pretreatment agent containing catalyst fine particles for electroless plating in which the arithmetic average particle diameter of secondary particles has a specific relationship with the mesh size. Therefore, the catalyst fine particles in the pretreatment agent are uniformly distributed in a size suitable for electroless plating without excessive aggregation in the pretreatment agent, and the catalyst is also obtained in the pretreatment layer similarly obtained. Microns are distributed uniformly. Thereby, the electroless plating layer provided thereon can be formed quickly, accurately and uniformly. Therefore, by using such a pretreatment layer, a metal conductive layer having a high-definition mesh pattern can be easily formed. The light-transmitting electromagnetic wave shielding material thus obtained has a homogeneous mesh pattern conductive layer, and can have a highly precise mesh pattern conductive layer as designed.

  Further, the mesh-shaped pretreatment layer of the present invention is a pretreatment in which the catalyst particles for electroless plating are dispersed so that the arithmetic average particle size of the secondary particles has a specific relationship with the shape of the printing plate recess. It can be advantageously obtained by printing the agent.

  Such a light-transmitting electromagnetic wave shielding material of the present invention is particularly suitable as an optical filter for a display such as a PDP.

  The light-transmitting electromagnetic wave shielding material of the present invention and the manufacturing method thereof will be described in detail below.

  An example of a schematic cross-sectional view for explaining each step of the method for producing a light-transmitting electromagnetic wave shielding material of the present invention is shown in FIG. In the method of the present invention, first, an electroless plating pretreatment agent containing electroless plating catalyst fine particles is printed on the transparent substrate 11 in a mesh using an intaglio printing plate, and the mesh-like on the transparent substrate 11 is printed. The pretreatment layer 12 is formed (arrow A1 in FIG. 1). Next, a metal conductive layer 13 is formed on the mesh-shaped pretreatment layer 12 by electroless plating using fine particles for electroless plating catalyst (arrow A2 in FIG. 1). Furthermore, in order to impart antiglare properties to the metal conductive layer, the metal conductive layer 13 is blackened or black-plated to form a blackened layer 14 on at least a part of the surface of the metal conductive layer 13 ( You may implement the arrow (A3) of FIG.

  The above steps ((A1), (A2), (A3)) will be described in detail below.

  The electroless plating pretreatment agent used in the step (A1) is generally a catalyst fine particle or surface of a composite metal oxide and / or composite metal oxide hydrate containing noble metal as a catalyst fine particle for electroless plating. Including fine particles containing noble metal such as fine particles (preferably metal oxide fine particles) on which noble metal (preferably Pd) is supported, synthetic resin, etc., and dispersed in the electroless plating pretreatment agent The arithmetic average particle diameter of the secondary particles of the electroless plating catalyst particles is in the range of 10% or less of the recess width and 20% or less of the recess depth in the mesh pattern of the intaglio printing plate. The electroless plating pretreatment layer 12 using fine particles for electroless plating catalyst such as a composite metal oxide containing noble metal and / or a composite metal oxide hydrate can be subsequently reduced to activate the noble metal. preferable. In the pretreatment agent and in the pretreatment layer, it is difficult to disperse the electroless plating catalyst particles as primary particles, and usually secondary particles are formed.

  In addition, one or more coating layers may be provided on the transparent substrate 11 for the purpose of improving adhesion to the pretreatment layer, transferability, and shape retention.

  FIG. 2 is a schematic sectional view for explaining the step (A1) of FIG. 1 in detail.

  FIG. 2 shows a step of forming a mesh-like pretreatment layer by printing an electroless plating pretreatment agent on the surface of a transparent substrate by gravure printing, which is one type of intaglio printing. The cylinder 10 having the mesh pattern carved on the surface is rotated in the direction of the arrow, and the electroless plating pretreatment agent 12 ′ is applied to the mesh pattern surface by the doctor blade 15, thereby the electroless plating pretreatment agent 12 ′. Is held in the recesses of the engraved mesh pattern. The cylinder 11 having the rotating electroless plating pretreatment agent 12 ′ is in contact with the transparent substrate 14 conveyed by the roll 16, so that the electroless plating pretreatment agent 12 ′ in the recessed portion of the engraved mesh image becomes a transparent substrate. 14 is transferred to the surface of 14 to form a pretreatment agent layer (which becomes the pretreatment layer 12 after drying). Then, the arithmetic average particle diameter of the secondary particles of the electroless plating catalyst particles dispersed in the electroless plating pretreatment agent 12 ′ is the concave width (in FIG. 2) of the mesh pattern of the intaglio printing plate (cylinder 10). w: 10% or less of the top width) and 20% or less of the recess depth (h in FIG. 2: distance between the straight line connecting the both ends of the recess and the bottom surface). It is preferably 1% or more of the recess width and 2% or more of the thickness of the recess depth.

  As described above, since the arithmetic average particle diameter of the secondary particles of the electroless plating catalyst particles is suppressed within the above range, the catalyst fines do not aggregate excessively, and the size is suitable for electroless plating. It is a collection. That is, since the secondary particles of the electroless plating catalyst particles easily enter the recesses of the intaglio printing plate, the pretreatment liquid containing the secondary particles of the catalyst particles is sufficiently secured in the recesses of the intaglio printing plate, thereby Printing can be performed uniformly, and a predetermined mesh shape can be easily obtained.

  For this reason, the electroless plating layer provided on this layer can be formed rapidly, accurately and uniformly. Therefore, by using such a pretreatment layer, a metal conductive layer having a high-definition mesh pattern can be easily obtained. The light-transmitting electromagnetic wave shielding material thus obtained has a homogeneous mesh pattern conductive layer, and can have a highly precise mesh pattern conductive layer as designed.

  In the specific arithmetic average particle size of the secondary particles of the electroless plating catalyst particles of the present invention, when the arithmetic average particle size exceeds the above range, the electroless plating catalyst particles are formed in the recesses of the intaglio printing plate. Since secondary particles are less likely to enter, the density of catalyst particle nuclei in the printed pretreatment layer is reduced, and a predetermined mesh shape cannot be easily obtained, making it difficult to obtain a uniform plating film.

  Moreover, if it is less than the minimum of a preferable range, it will become easy to generate | occur | produce fogging in printing, a catalyst particle will be printed also in a mesh opening part, and plating unevenness will arise in many cases.

Further, the arithmetic average particle diameter of the secondary particles of the electroless plating catalyst particles in the pretreatment agent advantageously obtained by the method of the present invention is the line width (W _{1 in} FIG. 3) in the mesh pattern of the pretreatment layer 12. 10% or less and the thickness or less. It is preferably 0.5% or more of the line width and 2% or more of the thickness.

  In addition, the arithmetic average particle diameter of the secondary particles of the electroless plating catalyst particles dispersed in the pretreatment layer 12 of the present invention substantially corresponds to that in the pretreatment agent.

  In the pretreatment agent of the present invention, the fine particles for electroless plating catalyst are well dispersible (in this case, it is preferable to use a dispersant). It is possible to form a mesh-shaped pretreatment layer having a high accuracy. Moreover, the composite metal oxide fine particles, the composite metal oxide hydrate fine particles, and the fine particles (especially the latter) on which noble metal is supported on the surface have high stability and plating metal precipitation ability. Therefore, a metal conductive layer without selective variation can be quickly formed on the pretreatment layer by electroless plating in a later step, and a mesh-like metal conductive layer having a uniform thickness can be obtained. It becomes. Furthermore, the adhesion between the transparent substrate and the metal conductive layer in the pretreatment layer is improved by the synthetic resin, which makes it difficult for the pretreatment layer to be peeled off, and enables the metal conductive layer to be formed more accurately.

  Next, in the method of the present invention, the metal conductive layer 13 is formed on the mesh-shaped pretreatment layer 12 by performing the electroless plating treatment in step A2 (arrow A2 in FIG. 1). Here, fine metal particles are deposited and formed as a dense and substantially continuous film on a pretreatment layer formed using fine particles for electroless plating catalyst, and selectively adhere to the pretreatment layer to achieve high definition. A metal conductive layer having a fine pattern can be formed.

  Thus, according to the present invention, a fine pattern is obtained by making the arithmetic average particle size of secondary particles of the electroless plating catalyst particles of the electroless plating pretreatment agent as described above. Thus, a light-transmitting electromagnetic wave shielding material excellent in both light transmittance and electromagnetic wave shielding properties can be obtained. Furthermore, fine particles of composite metal oxide and composite metal oxide hydrate excellent in dispersibility, or metal oxide fine particles with Pd supported on the surface, there is no formation of streaks or fog due to excessive aggregation of particles, A light-transmitting electromagnetic wave shielding material excellent in appearance and visibility can be obtained.

  Hereinafter, the light-transmitting electromagnetic wave shielding material of the present invention and the method for producing the electromagnetic shielding material of the present invention will be described in more detail.

  The electroless plating catalyst particles used in the electroless plating pretreatment agent of the present invention are generally metal particles of a composite metal oxide or composite metal oxide hydrate, or a metal on which a noble metal (preferably Pd) is supported. Oxide fine particles.

  As the composite metal oxide and the composite metal oxide hydrate, those containing at least two metal elements selected from the group consisting of Pd, Ag, Pt, Au, Si, Ti, and Zr are preferably used. More preferably, one containing a metal element of Pd or Ag and a metal element of Si, Ti or Zr is mentioned. 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). It is particularly preferable to use a composite metal oxide hydrate.

In the formula (I), M ¹ is Pd or Ag, but is 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.

Examples of the composite metal oxide hydrate _{is, PdSiO 3, Ag 2 SiO 3} , PdTiO 3, Ag 2 TiO 3, hydrates of such PdZrO ₃ and Ag ₂ TiO ₃ and the like. In particular, PdTiO ₃ · 6 (H ₂ O) is preferable.

  The composite metal oxide hydrate is a raw material of each corresponding metal salt, for example, hydrochloride, sulfate, nitrate, halide, oxyhalide, hydrate of the corresponding metal oxide, etc., and these are heated. It can be 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 are as defined in the above formula (I)) are preferably used.

  The arithmetic average particle size of secondary particles of the composite metal oxide and the catalyst particles for electroless plating of the composite metal oxide hydrate used in the pretreatment agent for electroless plating is 0.1 to 10 μm, and further 0.1 It is preferably in the range of ˜3 μm, particularly in the range of 0.1 to 1 μm. The arithmetic average particle diameter of the primary particles is preferably in the range of 0.01 to 1 μm. Thereby, it can be set as the composite metal oxide which has the high dispersibility in which aggregation was suppressed, and catalytic activity, the said composite metal oxide hydrate, etc.

  The electroless plating catalyst particles of the present invention are dispersed in the pretreatment agent and in the pretreatment layer in the form of secondary particles having an arithmetic average particle diameter in the specific range described above. This arithmetic average particle size is determined by measuring the catalyst particles (secondary particles) in the pretreatment agent (and in the pretreatment layer) with a laser diffraction / scattering particle size distribution analyzer (trade name: LA920; manufactured by Horiba, Ltd.). And cyclohexanone is used as a diluent solvent, and the arithmetic average particle size is calculated in terms of volume with a relative refractive index of 1.80.

  As the electroless plating catalyst particles, it is preferable to use metal oxide fine particles having a noble metal (preferably Pd) supported on the surface. A noble metal can be efficiently used as a catalyst. When such metal oxide fine particles are used, it is easy to disperse in the state of secondary particles having the specific arithmetic average particle diameter by using a dispersant described later.

  The fine particles with the noble metal supported on the surface may be inorganic fine particles or organic fine particles, but inorganic fine particles are preferred. Examples of the inorganic fine particles include inorganic pigments such as silica, alumina, alumina aerosol, clay, kaolin, talc, calcium sulfate, calcium carbonate, and glass flakes, and alumina, silicon dioxide, titanium dioxide, and particularly titanium dioxide are preferable. . Organic resin of organic resin fine particles includes phenol resin, amino resin, polyester resin, melamine resin, epoxy resin, divinylbenzene polymer, styrene / divinylbenzene copolymer, acrylic resin or styrene / (meth) acrylate copolymer. Can be mentioned. Acrylic resins (eg, polymers and copolymers of (meth) acrylates such as alkyl (meth) acrylate) and styrene / (meth) acrylate copolymers are preferred. The organic resin of the organic resin fine particles is preferably cured.

  The average particle diameter of the fine particles is preferably in the range of 0.01 to 10 μm, more preferably in the range of 0.05 to 3 μm, and particularly preferably in the range of 0.1 to 1 μm. Thereby, the line width of the mesh can be reduced. The arithmetic average particle diameter of the secondary particles of the fine particles having a noble metal is preferably 0.1 to 10 μm, more preferably 0.1 to 3 μm, and particularly preferably 0.1 to 1 μm. The arithmetic average particle diameter of the primary particles is preferably in the range of 0.01 to 1 μm.

  Moreover, as said noble metal, palladium, silver, platinum, and gold | metal | money are preferable and especially the above palladium (Pd) is preferable. Pd may be fine particles or a thin layer.

  The fine particles having a noble metal on the surface used for the pretreatment layer are, for example, by treating the fine particles with a solution containing a noble metal chloride and tin chloride, and then performing a reduction treatment (eg, acid treatment), or It is obtained by treating the fine particles with a solution containing a mixture or reaction product of a silane coupling agent and an azole compound and a noble metal compound.

  Specifically, fine particles having a noble metal on the surface can be obtained, for example, as follows using the fine particles.

  First, the surface of the fine particles is alkali degreased and then neutralized with an acid. The fine particles treated in this way are treated as follows.

1) A method of treating the fine particles with a tin chloride solution to sensitize the surface (sensitizing) and then treating with palladium chloride to activate (activate) to produce metallic palladium;
2) The above fine particles are treated with a tin chloride / palladium chloride solution to form a Pd-Sn complex (catalyst), reduced with hydrochloric acid or the like to dissolve the tin salt, and metallic redox is produced by the oxidation-reduction reaction. Or 3) a method of treating fine particles with a solution containing a mixture or reaction product of a silane coupling agent and an azole compound and palladium chloride (noble metal compound).

  As a reducing agent used for the reduction treatment of the noble metal ion in the method 2), an inorganic salt such as sodium borohydride or a compound thereof, an inorganic acid such as hydrochloric acid, a formic acid, acetic acid, citric acid, or the like. 6 organic acids, aldehydes having 1 to 2 carbon atoms such as formaldehyde and acetaldehyde, alcohols having 1 to 3 carbon atoms such as methanol, ethanol and propanol, and reducing gases such as hydrogen, ethylene and carbon monoxide be able to. In order to obtain an extremely thin noble metal film, the reducing agent is particularly preferably an inorganic acid such as hydrochloric acid.

  In the method 3), the silane coupling agent used in the treatment solution for forming fine particles having a noble metal on the surface is preferably one having a functional group having a metal-capturing ability in one molecule. As a result, it is possible to achieve an electronic state and orientation that effectively expresses the activity of the noble metal that is the electroless plating catalyst. Moreover, high adhesiveness with a transparent substrate is also 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 preferred because the pretreatment layer obtained exhibits high adhesion to the transparent substrate and the metal conductive layer.

  Next, as the azole compound used in the treatment solution for forming fine particles having a noble metal on the surface, imidazole, oxazole, thiazole, selenazole, pyrazole, isoxazole, isothiazole, triazole, oxadiazole, thiadiazole, tetrazole Oxatriazole, thiatriazole, benzazole, indazole, benzimidazole, benzotriazole, indazole and the like. Although not limited to these, imidazole is particularly preferred because of its excellent reactivity with functional groups such as epoxy groups and noble metal compounds possessed by the silane coupling agent.

  In the treatment solution for forming fine particles having a noble metal on the surface in the method of 3), the silane coupling agent and the azole compound may be simply mixed, but these are reacted in advance to obtain a reaction product. It may be formed. 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. At that time, a solvent is not particularly required, but an organic solvent such as chloroform, dioxanemethanol, ethanol or the like may be used in addition to water. A treatment solution is obtained by mixing a noble metal compound with the reaction product of the silane coupling agent and the azole compound thus obtained.

  The noble metal compound used in the treatment solution for forming fine particles having a noble metal on the surface of the present invention exhibits a catalytic effect capable of selectively depositing and growing a metal such as copper or aluminum in the electroless plating treatment. It is. Specifically, since high catalytic activity can be obtained, it is preferable to use a compound containing a metal atom such as palladium, silver, platinum, and gold as described above. Examples of such a compound include metal atom chlorides, hydroxides, oxides, sulfates, ammonium salts, and other ammine complexes, among which palladium compounds, particularly palladium chloride, are preferred.

  The treatment solution for forming fine particles having a noble metal on the surface used in the method 3) is preferably 0.001 to 50 mol%, more preferably 0, of the noble metal compound with respect to the azole compound and the silane coupling agent. It is good to contain 1-20 mol%. If the concentration of the noble metal compound is less than 0.001 mol%, sufficient catalytic activity may not be obtained and a metal conductive layer having a desired thickness may not be formed. If the concentration exceeds 50 mol%, the noble metal commensurate with the increase in the amount added. There is a possibility that the catalytic effect of the compound cannot be obtained.

  Further, the treatment solution for forming fine particles having a noble metal on the surface of the present invention 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, and dioxane. These may be used individually by 1 type and may be used in mixture of 2 or more types.

  The content of the electroless plating catalyst particles such as fine particles having a noble metal on the surface in the electroless plating pretreatment agent is 10 to 50% by mass, particularly with respect to the total amount (solid content) of the electroless plating pretreatment agent. It is preferable that it exists in the range of 15-45 mass%. The pretreatment layer also generally contains the above amount of catalyst particles relative to the total amount of the pretreatment layer. Thereby, a pretreatment layer having high adhesion can be formed. Other electroless plating catalyst particles are preferably used in the same amount.

  Next, the synthetic resin used for the electroless plating pretreatment agent is not particularly limited as long as it can secure adhesion to the transparent substrate and the metal conductive layer. Examples of preferred synthetic resins include acrylic resins, polyester resins, polyurethane resins, vinyl chloride resins, and ethylene vinyl acetate copolymer resins. By using these, high adhesiveness with a transparent substrate and a metal conductive layer is obtained, and a metal conductive layer can be accurately formed on a pretreatment layer. These synthetic resins may be used alone or in combination of two or more. In the present invention, a polyester resin and a polyurethane resin are preferable, and a polyester resin is particularly preferable.

  Examples of acrylic resins 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. Similar homopolymers and copolymers can be used.

  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-based urethane resin, a polyether-based urethane resin, and a polycarbonate-based urethane resin. Of these, polyester urethane resins are preferred.

  As the polyurethane resin, a polyester urethane resin comprising a reaction product of a polyester polyol and a polyisocyanate compound can be used. The average molecular weight of the polyester-based 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, and a polycarbonate diol. Examples of the low molecular weight diol 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. be able to. 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 Two or more types are used. Moreover, (epsilon) -caprolactone etc. are used for the said lactone.

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

  Polyisocyanate compounds 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 phenylsulfonyl). Aliphatic diisocyanates (for example, 1,6-hexamethylene diisocyanate); polyisocyanates of alicyclic diisocyanates (for example, isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, etc.), or these The 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 the said polyester-type urethane resin, it is preferable that an electroless-plating pretreatment agent further contains a polyisocyanate hardening | curing agent. As the polyisocyanate curing agent, the above-described polyisocyanate compound is used. The content of the curing agent is preferably 0.1 to 5 parts by mass, particularly 0.1 to 1.0 part by mass with respect to 100 parts by mass of the polyester-based 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-2-ethylhexyl acrylate copolymer resin, copolymer resins of vinyl chloride and olefins such as vinyl chloride-ethylene copolymer resin, vinyl chloride-propylene copolymer resin, Representative examples include vinyl chloride-acrylonitrile polymer resin. It is particularly 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 of the present invention, one having a functional group containing active hydrogen at the molecular end is preferably used 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. Among these, primary amino group, secondary amino group, imino group, amide group, imide group, hydroxyl group, formyl group, carboxyl group, sulfonic acid group, and thiol group are preferable. In particular, a primary amino group, a secondary amino group, an amide group, and a hydroxyl group are 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 in the range of 20 to 80% by mass, particularly 30 to 70% by mass, based on the total amount (solid content) of the electroless plating pretreatment agent. . The pretreatment layer also generally contains the above amount of synthetic resin relative to the total amount of the pretreatment layer. In that case, it is preferable to contain the said synthetic resin. Thereby, a pretreatment layer having high adhesion can be formed.

  In the present invention, it is preferable to use a dispersing agent in order to favorably disperse in the electroless plating pretreatment agent so that the electroless plating catalyst particles have the specific secondary particle size. This is particularly effective for fine particles (preferably metal oxide fine particles) having a surface carrying a noble metal (preferably Pd). Examples of the dispersant include polyacrylate, sodium maleate olefin copolymer, dioctyl sulfosuccinate, polyoxyethylene alkyl (aryl) ether, amine ester of polyether ester acid, polyether phosphate ester, polyether Examples thereof include amine salts of phosphate esters. Preferred dispersants include high molecular weight dispersants such as polyether ester acid amine salts, polyether phosphate esters, and polyether phosphate ester amine salts. In particular, an amine salt of a polyether phosphate ester (especially, an acid value of 10 to 20 and an amine value of 10 to 30 is preferable) is mentioned. Can do.

  The content of the dispersant (solid content) in the electroless plating pretreatment agent is preferably in the range of 0.1 to 10 parts by mass, particularly 0.2 to 5 parts by mass with respect to 100 parts by mass of the catalyst particles.

The electroless plating pretreatment agent of the present invention may contain a thixotropic agent. Examples of the thixotropic agent include inorganic fillers such as silicon oxide such as silicon dioxide, calcium carbonate, aluminum oxide, bentonite, clay and talc; vegetable oils such as hardened castor oil; amide wax, modified urea, urea modified polyamide, carnauba wax , Waxes such as stearic acid amide and hydroxystearic acid ethylene bisamide. Of these, silicon oxide is preferable because it is chemically stable, has a small particle size, and has a large thixotropic effect. Silicon oxide, commonly referred to as silica, BET specific surface area is 20 to 500 m ² / g, especially 50 to 400 m ² / g is preferably an average primary particle size of 4 to 50 nm, especially 5~30nm It is preferable. Examples of preferable commercial products of silica include AEROSIL-50, 200, 300, 380 and R972 manufactured by Nippon Aerosil Co., Ltd.

  The content of the thixotropic agent in the electroless plating pretreatment agent is preferably in the range of 5 to 50 parts by mass, particularly 7 to 40 parts by mass with respect to 100 parts by mass of the synthetic resin.

  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 examples of the black colorant 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 diameter of carbon black is preferably 0.1 to 1000 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 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.

  The electroless plating pretreatment agent may contain a suitable organic solvent. As organic solvents, methyl alcohol, ethyl alcohol, 2-propanol, acetone, toluene, ethylene glycol, polyethylene glycol, dimethylformamide, dimethyl sulfoxide, dioxane, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, xylene Etc. 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 and surfactants as necessary.

  In the method of the present invention, the transparent substrate to which the pretreatment agent is applied is not particularly limited as long as it has transparency and flexibility and can withstand subsequent processing. Examples of the material of the transparent substrate include glass, polyester (eg, polyethylene terephthalate, (PET), polybutylene terephthalate, polyethylene naphthalate, (PEN)), acrylic resin (eg, polymethyl methacrylate (PMMA)), polycarbonate ( PC), polystyrene, cycloolefin (COP), polyethersulfone (PES), cellulose triacetate (TAC), polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion Crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane, etc. can be mentioned. Among these, it is a highly transparent material with little deterioration due to processing (heating, solvent, bending). PET, PEN, PC, TAC, PMMA is 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, and is usually 0 depending on the form in use and the required mechanical strength. The thickness is appropriately set within a range of 0.05 to 5 mm.

  In the present invention, as described above, the electroless plating pretreatment agent is advantageously printed on the transparent substrate in a mesh form using an intaglio printing plate, thereby advantageously forming a mesh pretreatment layer on the transparent substrate. can do. Thereby, a pretreatment layer having a desired fine pattern can be formed by a simple method.

  In order to print the electroless plating pretreatment agent on the transparent substrate, a printing method such as gravure printing, screen printing, offset printing, ink jet printing, electrostatic printing, flexographic printing, gravure offset printing, letterpress reversal offset printing, or the like is used. it can. In the production method of the present invention, intaglio printing, particularly gravure printing is used. When using gravure printing, the printing speed is preferably 5 to 50 m / min.

  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, and if it exceeds 160 ° C., the substrate may be thermally damaged. The drying time for heat drying after coating is preferably 5 seconds to 5 minutes.

  The shape of the pattern in the mesh-shaped pretreatment layer is not particularly limited, and examples thereof include a lattice shape in which square holes are formed, and a punching metal shape in which circular, hexagonal, triangular, or elliptical holes are formed. It is done. Further, the holes are not limited to those regularly arranged, and may be a random pattern.

  From the viewpoint of imparting high light transmittance and electromagnetic wave shielding properties to the metal conductive layer, it is desirable that the openings in the pretreatment layer are regularly arranged at equal intervals. In order to form a metal conductive layer having a high light transmittance, it is desirable that the shape of the opening in the metal conductive layer is a square shape, particularly a square or a rectangle, and the aperture ratio is high. Therefore, it is preferable that the size of the opening in the pretreatment layer is very small. For example, FIG. 3 shows an example of the pattern of the pretreatment layer 12 in which the opening 15 has a square shape.

In the pretreatment layer, it is preferable that the line width (W ₁ ) is _{1 to} 40 μm, the aperture ratio is 50 to 95%, the line width (W ₁ ) is 5 to 30 μm, and the aperture ratio is 60 to 95%. The aperture ratio of the pretreatment layer refers to the area ratio occupied by the opening portion in the projected area of the pretreatment layer (the area excluding the outer frame if there is an outer frame). In the pretreatment layer, the line spacing (W ₂ ) is preferably 50 to 1000 μm, more preferably 100 to 400 μm. Thus, according to the present invention, a pretreatment layer having a fine pattern can be formed with high accuracy.

  The pretreatment layer may have the above-described mesh pattern at the central portion on the transparent substrate, and may have a frame-shaped pattern with no opening at the peripheral edge except the central portion on the transparent substrate. Good. If a metal conductive layer is formed on the pretreatment layer having such a configuration, a portion having a frame-like pattern in the metal conductive layer can protect a portion having a mesh-like pattern.

  The thickness of the pretreatment layer is preferably in the range of 0.01 to 3 μm, more preferably 0.1 to 3 μm, and particularly preferably 0.1 to 1.5 μm. Thereby, the high adhesiveness with a transparent substrate and a metal conductive layer is securable. Further, the electroless plating can be formed in a predetermined shape with a uniform film thickness. Furthermore, by reducing the thickness of the pretreatment layer, not only can the visibility of the light-transmitting electromagnetic wave shielding material be viewed from an oblique direction even when a mesh-shaped metal conductive layer is formed, Smoothing is facilitated when a hard coat layer or the like is formed on the transparent electromagnetic shielding material.

In the method of the present invention, after the step of forming the mesh-shaped pretreatment layer on the transparent substrate as described above, before the step of forming the mesh-shaped metal conductive layer (arrow (A2) in FIG. 1). It is preferable to perform a step of performing a reduction treatment on the pretreatment layer 12. By carrying out the reduction treatment, the metal species contained in the composite metal oxide and composite metal oxide hydrate which are the electroless plating catalysts contained in the pretreatment layer 12 are reduced, and only the metal species which are active components are ultrafine particles. Can be activated uniformly. Since the metal species thus reduced and precipitated have high catalytic activity and are stable, the adhesion between the pretreatment layer 12 and the transparent substrate 11 and the deposition rate of electroless plating are improved. It is possible to reduce the amount of oxide and composite metal oxide hydrate used.

  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. For example, a gas phase reduction method in contact with the substrate can be used.

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

The solution containing the 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, hypophosphorous acid, hypophosphite such as sodium hypophosphite, hydroxylamine sulfate, Examples thereof include sulfites such as sodium sulfite, hydrosulfite (Na ₂ S ₂ O ₄ : also referred to as sodium dithionite), and the like. If the reducing agent is the same as the reducing agent contained in the electroless plating bath used in the subsequent step, electroless plating can be performed without washing the transparent substrate after the reduction treatment, There is little risk of changing the composition of the electroless plating 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.

  In the liquid phase reduction method, as a method of using a solution containing a reducing agent, high reducibility of catalyst particles such as composite metal oxide and composite metal oxide hydrate contained in the pretreatment layer can be obtained. It is preferable to use a method of immersing the transparent substrate on which the pretreatment layer 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 50 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 by electroless plating treatment is performed on the pretreatment layer formed as described above. By performing the electroless plating treatment, fine metal particles are deposited and formed as a dense and substantially 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, copper, nickel, gold, silver, platinum, palladium, tin, cobalt, or the like can be used. In particular, copper or nickel is preferably used because it is advantageous in terms of cost because a metal conductive layer with high electromagnetic shielding properties can be obtained. The metal conductive layer formed using these plating 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, it is performed by immersing the plating base in a plating solution containing a plating metal salt, a chelating agent, a pH adjuster, a reducing agent, etc. as a basic composition, or adding the constituent plating solutions 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 metal 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 0.5 10 g / L, especially 1 to 5 g / L, a solution 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 the transparent substrate on which the pretreatment layer is formed 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.

  In the method of the present invention, after the electroless plating is performed on the transparent substrate on which the pretreatment layer is formed so that the metal conductive layer has a desired thickness and line width, the electrolytic plating may be further performed. Good.

  As the plating metal in the electroplating, the same metal as described above in the electroless plating is used.

  Electroplating is not particularly limited, and may be performed according to a conventional method. For example, a transparent substrate on which a mesh-shaped pretreatment layer and a metal conductive layer are formed is immersed in a plating solution, the transparent substrate is used as a cathode, a single plating metal is used as an anode, and an electric current is applied to the plating solution. . The composition of the plating solution is not particularly limited. For example, when forming a metal conductive layer made of Cu, an aqueous copper sulfate solution or the like is used.

  There is no restriction | limiting in particular in the shape of the pattern in a mesh-shaped metal conductive layer, It is the same as that mentioned above in the pretreatment layer.

In the metal conductive layer, it is preferable that the line width (W ₁ ) is _{1 to} 40 μm, the aperture ratio is 50 to 95%, the line width (W ₁ ) is 5 to 30 μm, and the aperture ratio is 60 to 95%. In addition, the aperture ratio of a metal conductive layer means the area ratio which the opening part occupies in the projection area of the said metal conductive layer (area | region except it when there exists an outer frame). In the metal conductive layer, the line spacing (W ₂ ) is 50 to 1000 μm, preferably 100 to 400 μm. As described above, according to the present invention, the metal conductive layer can be accurately formed on the pretreatment layer having a fine pattern.

  In addition, as described in the description of the pretreatment layer, the metal conductive layer has the mesh-like pattern described above at the central portion on the transparent substrate, and a frame-like pattern at the peripheral portion excluding the central portion on the transparent substrate. You may have.

  The metal conductive layer has a thickness of 1 to 200 μm, preferably 2 to 10 μm. If the thickness of the metal conductive layer is too thin, sufficient electromagnetic wave shielding properties may not be obtained. If the thickness is too thick, it is not preferable from the viewpoint of reducing the thickness of the light-transmitting electromagnetic wave shielding material.

  In the method of the present invention, as described above, in order to impart antiglare properties to the metal conductive layer, the metal conductive layer 13 is subjected to blackening treatment or black plating treatment, and at least a part of the surface of the metal conductive layer 13 is blackened. The step of forming the chemical treatment layer 14 (arrow (A3) in FIG. 1) may be further performed.

  In the blackening treatment, the metal conductive layer surface is roughened and / or blackened. The metal conductive layer is preferably oxidized or sulfided. 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.

  Further, as the blackening treatment, black plating may be performed in addition to the oxidation treatment or the sulfurization treatment. Thereby, the blackening process layer which was excellent in adhesiveness and was fully blackened can be formed.

  The black plating process may be performed according to a conventionally known method, and may be performed using either electrolytic plating or electroless plating. Moreover, black plating is performed by plating copper, cobalt, nickel, zinc, tin, chromium, and alloys thereof. In order to sufficiently blacken, it is preferably performed by black plating of an alloy containing at least one metal selected from the group consisting of nickel, zinc, and chromium.

  For example, in order to form a blackening treatment layer made of an alloy of nickel and zinc, nickel sulfate 50 to 150 g / L, nickel sulfate ammonium 10 to 50 g / L, zinc sulfate 20 to 50 g / L, sodium thiocyanate 10 to 30 g A plating bath containing / L and sodium saccharin 0.05 to 3 g / L can be used. Thereafter, black plating may be performed by electrolytic plating or the like according to a conventional method.

  The thickness of the blackening treatment layer is not particularly limited, but is 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.

  According to the method of the present invention described above, noble metal-containing composite metal oxide and / or composite metal oxide hydrate fine particles, or catalyst particles such as fine particles having a noble metal supported on the surface, if necessary, a dispersant, a synthetic resin, etc. By using an electroless plating pretreatment agent containing, a metal conductive layer having a fine pattern can be accurately provided, and light transmissive electromagnetic waves excellent in light transmittance, electromagnetic shielding properties, appearance and visibility A shield material can be obtained.

  By using the electroless plating pretreatment agent of the present invention, the light transmissive electromagnetic wave shielding material has high light transmittance in the pretreatment layer. Therefore, the light transmittance of the light transmissive electromagnetic wave shielding material is not lowered by the formation of the pretreatment layer, and the light transmissive electromagnetic wave shielding material is 70% or more, particularly 75 to 90% high total light. It has transmittance.

  In addition, the measurement of the total light transmittance of the light-transmitting electromagnetic wave shielding material is performed using the fully automatic direct reading haze computer HGM-2DP (manufactured by Suga Test Instruments Co., Ltd.) and the like in the thickness direction of the light-transmitting electromagnetic wave shielding material. This is done by measuring the light transmittance.

  In addition, since detailed description about each layer in the said light-transmitting electromagnetic wave shielding material is as above-mentioned in the manufacturing method of this invention, it abbreviate | omits here.

  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 has high light transmissive property and electromagnetic wave shielding property, it is suitably used for the display filter of the display device described above.

  Although the said filter for a display is not restrict | limited in particular, It is obtained by bonding the light-transmitting electromagnetic wave shielding material manufactured by the said method to transparent substrates, such as a glass plate, via an adhesive bond layer. In such a display filter, the openings of the mesh-shaped pretreatment layer and the metal conductive layer are filled with an adhesive layer.

  In addition to the transparent substrate, the electromagnetic wave shielding layer, and the adhesive layer, the electronic display filter may further include an antireflection layer, a color tone correction filter layer, a near infrared cut layer, and the like. 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.

  The light-transmitting electromagnetic wave shielding material of the present invention can also be used for information display panels. The information display panel includes an electrophoretic method, an electrochromic method, a thermal method, a two-color particle rotation method, and the like. Among these, an electrophoretic information display panel is preferable. The information display panel has a configuration in which a display medium is sealed between two substrates each having a conductive pattern layer. At this time, a conductive pattern layer is arrange | positioned inside or outside between base materials, and acts as an electrode. Then, by applying an electric field from the conductive pattern layer to the display medium, information such as an image can be displayed by moving the display medium. A cell isolated by a partition wall may be formed between the substrates, and the display medium may be enclosed in the cell.

  In such an information display panel, the light-transmitting electromagnetic wave shielding material of the present invention can be used for at least one of the two substrates on which the conductive pattern layer is formed. A specific configuration of the information display panel is described in Japanese Patent Application Laid-Open No. 2007-11227.

  In the information display panel, it is desirable that the conductive pattern layer used as the electrode is transparent in order to obtain a clear image. In the light transmissive electromagnetic wave shielding material of the present invention, the conductive pattern layer does not contain particles such as conductive powder, and therefore has excellent transparency. Furthermore, since the conductive pattern layer has a fine pattern, a very fine image can be stably displayed. Therefore, the light transmissive electromagnetic wave shielding material of the present invention is suitably used for an information display panel.

  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 Pretreatment agent formulation:
Titanium dioxide fine particles having Pd supported on the surface (Pd: 0.6% by mass of titanium dioxide,
Titanium dioxide average primary particle size: 0.21 μm) 60 parts by mass Polyester resin (100% solids,
Product name: Byron 670, manufactured by Toyobo Co., Ltd.) 100 parts by mass Dispersant (Disparon DA325, manufactured by Enomoto Kasei Co., Ltd.) 1.5 parts by mass Silica fine particles (average primary particle size: 12 nm,
Aerosil # 200, manufactured by Nippon Aerosil Co., Ltd.) 20 parts by mass Cyclohexanone 560 parts by mass

The above ingredients were mixed and then stirred for 20 minutes in a bead mill. Thus, a pretreatment agent was prepared.

2. Preparation of mesh-shaped pretreatment layer Next, the obtained pretreatment agent was meshed on a PET film (thickness 100 μm) with a line width (recessed portion width) of 16 μm, a depth (recessed portion depth) of 6 μm, and a pitch of 200 μm. After printing with the gravure printing plate in which the pattern was engraved, it was dried at 100 ° C. for 30 minutes to form a mesh-like pretreatment layer having a thickness of 0.9 μm on the PET film.

[Example 2]
In Example 1, as the titanium dioxide fine particles having Pd supported on the surface, Pd is 0.6% by mass of titanium dioxide and the average primary particle diameter of titanium dioxide is 0.07 μm. A mesh-shaped pretreatment layer was formed in the same manner except that the amount was changed to 3 parts by mass.

[Example 3]
In Example 1, a complex metal oxide hydrate (PdTiO ₃ .6H ₂ O; average primary particle size is 0.3 μm) is used in place of the titanium dioxide fine particles having Pd supported on the surface, and a dispersant is used. A mesh-like pretreatment layer was formed in the same manner except that it was not performed.

[Comparative Example 1]
A mesh-shaped pretreatment layer was formed in the same manner as in Example 1 except that the dispersant was not used.

[Comparative Example 2]
In Example 2, a mesh-shaped pretreatment layer was formed in the same manner except that the dispersant was not used.
[Evaluation]
(1) Further, on the pretreatment layers obtained in Examples and Comparative Examples, a metal conductive layer was formed as follows to produce a light transmissive electromagnetic wave shielding material.

3. Production 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 5 minutes. An electroless copper plating treatment was performed to obtain a mesh-like metal conductive layer.
(2) The obtained light-transmitting electromagnetic wave shielding material was evaluated as follows.
(A) Surface resistance (Ω / □)
The surface resistance value was measured using a surface resistivity meter (Loresta AP) manufactured by Mitsubishi Yuka Co., Ltd. The evaluation was expressed as “O” for 10Ω / □ or less and “X” for exceeding 10Ω / □.
(B) State of electroless plating The state of the obtained mesh-like metal conductive layer was observed using a microscope.
(3) Arithmetic mean particle diameter of secondary particles of catalyst particles The catalyst particles (secondary particles) in the pretreatment agent are converted into a laser diffraction / scattering particle size distribution analyzer (trade name: LA920; manufactured by Horiba, Ltd.). It measured using. That is, first, the pretreatment agent was sufficiently diluted to a measurable range level using cyclohexanone as a diluent solvent, poured into a batch type measurement cell, and then measured while stirring with a magnetic stirrer. From the measurement results, the arithmetic average particle diameter was calculated in terms of volume with the relative refractive index (= catalyst particle refractive index / cyclohexanone refractive index) being 1.80.

  The results obtained are shown in the table below.

  By using a pretreatment agent having a specific arithmetic average particle diameter in the secondary particles of the catalyst particles of the present invention obtained in Examples 1 to 3, a high-definition pattern can be printed by gravure printing and uniform. It was found that a conductive mesh can be obtained by applying electroless plating. As shown in Comparative Examples 1 and 2, when a pretreatment agent containing catalyst particles having a large secondary particle diameter outside the specific range of the present invention was used, electroless plating along the printed pattern of the pretreatment layer was performed. Could not be formed.

It is a schematic sectional drawing which shows the process in which a light-transmitting electromagnetic wave shielding material is manufactured using the pretreatment agent of the present invention. It is a schematic sectional drawing which shows the detail of process A1 of FIG. It is a schematic diagram which shows an example of the pattern of a pre-processing layer.

Explanation of symbols

11 Transparent substrate,
12, 22 mesh-shaped pretreatment layer,
13 mesh-like metal conductive layer,
14 Blackening treatment layer,
25 opening

Claims (15)

A transparent substrate, a mesh-shaped pretreatment layer on the transparent substrate, a light-transmitting electromagnetic wave shielding material comprising a mesh-like metal conductive layer provided on the pretreatment layer,
A pretreatment agent containing electroless plating catalyst particles having an arithmetic average particle diameter of secondary particles in which the pretreatment layer has a mesh shape of 10% or less of the line width and the thickness of the line or less, a transparent substrate A light-transmitting electromagnetic wave shielding material, characterized by being formed by coating on top.   The light-transmitting electromagnetic wave shield according to claim 1, wherein the arithmetic average particle diameter of secondary particles of the electroless plating catalyst particles is 0.5% or more of the line width of the mesh and 2% or more of the thickness of the line. Wood.   The light-transmitting electromagnetic wave shielding material according to claim 1 or 2, wherein the pretreatment agent contains a dispersant.   The light-transmitting electromagnetic wave shielding material according to any one of claims 1 to 3, wherein the electroless plating catalyst particles are fine particles containing a noble metal.   The light-transmitting electromagnetic wave shielding material according to claim 4, wherein the fine particles containing a noble metal are metal oxide fine particles having a noble metal supported on the surface.   The electroless plating pretreatment agent according to claim 5, wherein the metal oxide fine particles are titanium oxide fine particles.   The light-transmitting electromagnetic wave shielding material according to any one of claims 4 to 6, wherein the noble metal is at least one metal selected from the group consisting of palladium, silver, platinum, and gold.   The light-transmitting electromagnetic wave shielding material according to claim 4, wherein the fine particles containing a noble metal are fine particles of a noble metal-containing composite metal oxide or composite metal oxide hydrate.   The light-transmitting electromagnetic wave shielding material according to any one of claims 1 to 6, wherein the secondary particles of the electroless plating catalyst particles have an arithmetic average particle diameter of 0.1 to 1.0 µm.   The light-transmitting electromagnetic wave shielding material according to any one of claims 1 to 9, wherein the average primary particle size of the electroless plating catalyst particles is 0.01 to 1 µm.   The light-transmitting electromagnetic wave shielding material according to claim 1, wherein the pretreatment layer has a thickness of 0.1 to 3 μm. A method for producing the light-transmitting electromagnetic wave shielding material according to any one of claims 1 to 11,
By forming an electroless plating pretreatment agent containing electroless plating catalyst particles in a mesh form on a transparent substrate using an intaglio printing plate having a mesh pattern, a mesh-like pretreatment layer is formed on the transparent substrate. And the process of
Forming a mesh-shaped metal conductive layer by performing electroless plating on the pretreatment layer;
And the arithmetic average particle size of secondary particles of the electroless plating catalyst particles contained in the pretreatment agent for electroless plating is 10% or less of the recess width and 20% of the recess depth in the mesh pattern of the intaglio printing plate The manufacturing method of the light transmissive electromagnetic wave shielding material characterized by being in the following ranges.   The light-transmitting electromagnetic wave shielding material according to claim 12, wherein the arithmetic average particle diameter of secondary particles of the electroless plating catalyst particles is 1% or more of the recess width and 2% or more of the thickness of the recess depth. Method.   The method for producing a light-transmitting electromagnetic wave shielding material according to claim 12 or 13, wherein the pretreatment agent contains a dispersant.   The method for producing a light-transmitting electromagnetic wave shielding material according to any one of claims 12 to 14, wherein the intaglio printing plate is a gravure printing plate.

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