JP2010238855A - Method of manufacturing electromagnetic shielding light-transmissive window material, and electromagnetic shielding light-transmissive window material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a light-transmissive electromagnetic shielding material having a mesh-like metal conductive layer with superior size precision. <P>SOLUTION: The method of manufacturing an electromagnetic shielding light-transmissive window material includes steps of: forming an anchor coat layer 102 by coating a surface of a transparent base 101 with a composition containing a synthetic resin of ≤20°C in glass transition temperature and curing it; forming a mesh-like preprocessing layer 103 by printing, on the anchor coat layer 102, an electroless plating preprocessing agent containing a mixture of a silane coupling agent and an azole-based compound or a reaction product, and a nobel metal compound in meshes; and forming a mesh-like metal conductive layer 104 on the preprocessing layer 103 through electroless plating processing. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  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, electromagnetic waves from a mobile phone or the like may cause malfunction of precision equipment, and electromagnetic waves are regarded as a problem.

  Therefore, a light-transmitting electromagnetic wave shielding material having an electromagnetic wave shielding property and a light transmitting property has been developed and put into practical use as a front filter for a PDP of an OA device. 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 this purpose, for example, (1) a transparent base material is provided with an electromagnetic wave shielding layer made of a conductive mesh made of a metal wire or a conductive fiber mesh on one surface of a transparent substrate. Is done. 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) In general, a conductive ink containing conductive powder printed on a transparent base material in a mesh shape is known.

  Thus, in the 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 transparent conductive layer, extremely narrow the line width, and form a very fine 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, for example, a conductive ink containing a conductive powder such as metal powder or carbon powder and a resin, and an intaglio offset printing method on a transparent substrate. By using a method of forming a print pattern. Therefore, the light-transmitting electromagnetic wave shielding material (4) has an advantage that it can be produced by a simple method and at a low cost without requiring an etching process.

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

  Further, in Patent Document 2, pattern printing is performed with a catalyst ink containing a support prepared by supporting a 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 pattern-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. 336383

  However, in the electromagnetic wave shielding light-transmitting window material according to Patent Documents 1 and 2 described above, the conductive ink or catalyst ink printed on the transparent base material sags or spreads, so that these inks conform to the design dimensions. Printing with high accuracy was impossible, and it was difficult to form a mesh-like metal conductive layer having a fine pattern.

  Accordingly, an object of the present invention is to provide a method for producing a light-transmitting electromagnetic wave shielding material having a mesh-like metal conductive layer with excellent dimensional accuracy.

  As a result of various studies in view of the above problems, the present inventors have previously formed an anchor coat layer containing a synthetic resin having a specific glass transition temperature on a transparent substrate, and catalyst ink is formed on the anchor coat layer. It was found that the sagging and spreading of the catalyst ink after printing can be suppressed by printing.

  Furthermore, the present inventors include a pretreatment agent by using 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 as the catalyst ink. It was found that the catalyst ink can be printed with higher accuracy because the components to be dispersed are uniformly highly dispersed without agglomeration.

That is, the present invention is a process of forming an anchor coat layer by applying a composition containing a synthetic resin having a glass transition temperature of 20 ° C. or less to the surface of a transparent substrate and curing the composition.
On the anchor coat layer, a mixture or reaction product of a silane coupling agent and an azole compound, and an electroless plating pretreatment agent containing a noble metal compound are printed in a mesh shape to form a mesh-shaped pretreatment layer. And a process of
And a step of forming a mesh-like metal conductive layer on the pretreatment layer by electroless plating treatment.

  According to the method of the present invention, when the electroless plating pretreatment agent is printed on the anchor coat layer, the line width and thickness are uniform and the dimensional accuracy is excellent without occurrence of sagging, repelling, etc. A mesh pattern can be easily formed with little difference from the design dimension. Furthermore, a decrease in the thickness of the pretreatment layer due to sagging of the electroless plating pretreatment agent on the anchor coat layer is suppressed, and the transfer rate of the electroless plating pretreatment agent can be increased. Therefore, the mesh-shaped metal conductive layer can be obtained with excellent dimensional accuracy.

It is explanatory drawing explaining the method of this invention along each process.

  First, the 1st manufacturing method of this invention is demonstrated with reference to FIG.

  In the first method of the present invention, first, a step of forming the anchor coat layer 102 by applying a composition containing a synthetic resin having a glass transition temperature of 20 ° C. or less onto the transparent substrate 101 and curing the composition. (Arrow (1)). Next, 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 is printed on the anchor coat layer 102 in a mesh shape, and the mesh-like pretreatment is performed. A step of forming the layer 103 (arrow (2)) is performed. And the process (arrow (3)) of forming the mesh-shaped metal electroconductive layer 104 which consists of electroconductive materials, such as a metal, by the electroless-plating process on the said pretreatment layer 103 is implemented.

  An anchor coat layer is excellent in the absorbability of an electroless-plating pre-processing agent by including the synthetic resin whose glass transition temperature is 20 degrees C or less. Electroless plating pretreatment agent printed using direct gravure printing etc. on the anchor coat layer is moderately retained, and electrolessly smooth with almost the same dimensions and shape as designed without causing dripping or repellency. Printing of the plating pretreatment agent can be performed. Therefore, it is possible to form a fine mesh-shaped pretreatment layer having a small line width. Further, in the electroless plating pretreatment agent, the silane coupling agent, the azole compound, and the noble metal compound are uniformly highly dispersed. Therefore, it is possible to accurately form a mesh-shaped pretreatment layer having a fine pattern free from streaking and fogging. By performing an electroless plating process on such a mesh-shaped pretreatment layer, it is possible to form a fine mesh-shaped metal conductive layer having a small line width.

  Hereinafter, the method of the present invention will be described in detail step by step.

(Anchor coat layer formation process)
In the method of the present invention, first, a step of forming an anchor coat layer by applying a composition containing a synthetic resin having a glass transition temperature of 20 ° C. or less to the surface of a transparent substrate and curing the composition.

  The synthetic resin used for the anchor coat layer has a glass transition temperature of 20 ° C. or lower, preferably −10 to 10 ° C., particularly preferably −10 to 8 ° C. According to such a synthetic resin, a pretreatment layer excellent in absorbability of the electroless plating pretreatment agent can be formed. In addition, in this invention, the glass transition temperature of a synthetic resin can be implemented using the measuring method as described in the Example mentioned later.

  Specifically as a synthetic resin used for an anchor coat layer, a polyester resin, a polyurethane resin, an acrylic resin, and a cellulose resin can be mentioned preferably. These may be used alone or in combination of two or more. Other resins may be used in small amounts (about 20% by mass or less). Of these, polyurethane resins and polyester resins are preferable, and polyester resins are particularly preferable.

  The polyester resin is, for example, a method of using an acidic component such as a dibasic acid or an unsaturated dibasic acid and an alcohol component such as a polyhydric alcohol by appropriately selecting the type and ratio thereof and performing an esterification reaction. It can manufacture according to a conventionally well-known method. At this time, the glass transition temperature of the polyester resin can be adjusted by controlling the molecular weight and the degree of crosslinking of the polyester resin.

  Examples of the dibasic acid and unsaturated dibasic acid constituting the polyester resin include terephthalic acid, isophthalic acid and anhydrides thereof and lower alkyl esters thereof, adipic acid, sebacic acid, succinic acid, maleic acid, fumaric acid. Examples thereof include acids, tetrahydrophthalic acid, hexahydrophthalic acid, and anhydrides thereof. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, trimethylolethane, trimethylolpropane, glycerin, Examples include pentaerythritol.

  The pretreatment layer is preferably formed using a composition containing a synthetic resin having a group containing active hydrogen and a polyisocyanate having at least two isocyanate groups. By using the cured layer of such a composition as a pretreatment layer, the printing accuracy of the electroless plating pretreatment agent on the pretreatment layer can be further improved.

  Examples of the group containing active hydrogen include a hydroxyl group, a primary amino group, a secondary amino group, and a carboxyl group, and a hydroxyl group is preferable. The equivalent (eg, hydroxyl value) of the group containing active hydrogen is preferably in the range of 10 to 300 mgKOH / g, particularly 30 to 100 mgKOH / g, based on the synthetic resin (1 g).

  The polyisocyanate has at least two isocyanate groups. Specifically, aromatic polyisocyanates such as tolylene diisocyanate (TDI), isophorone diisocyanate, xylylene diisocyanate, diphenylmethane-4,4-diisocyanate; dicyclopentanyl diisocyanate, hexamethylene diisocyanate, 2,4,4 ′ -Trimethylhexamethylene diisocyanate, 2,2 ', 4-trimethylhexamethylene diisocyanate can be mentioned. Polyisocyanates such as trifunctional or higher functional isocyanate compounds such as a TDI adduct of trimethylolpropane can also be used. Of these, aromatic polyisocyanates are preferred.

  The content of the polyisocyanate is preferably 5 to 20 parts by mass, more preferably 5 to 15 parts by mass with respect to 100 parts by mass of the synthetic resin.

  It is preferable that the composition for forming an anchor coat layer further contains an organic solvent. Moreover, you may add a filler, surfactant, etc. to the said composition suitably.

  Specifically, as the organic solvent, a solvent belonging to the fourth class of first petroleums and a solvent belonging to the fourth class of second petroleums stipulated in the Fire Service Law are suitable.

  Examples of the solvent belonging to the first petroleums include toluene, ethyl acetate, isobutyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, isopropanol, and the like. Examples of the solvent belonging to the second type of second petroleum include xylene, n-butyl acetate, cellosolve, cellosolve acetate, n-butanol, isobutanol, and cyclohexanone. These may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  The anchor coat layer is generally formed by applying and curing a composition containing a synthetic resin and, if necessary, a polyisocyanate. As a method for applying the composition, any of existing coating methods such as gravure coating, micro gravure coating, die coating, lip coating, roll reverse coating, wire bar coating, and kiss coating can be employed. Curing can also be performed at room temperature, in which case, for example, it is allowed to stand for 1 to 5 days (particularly 2 to 4 days). If heated, the heating time is shortened according to the temperature.

  The composition coated on the transparent substrate is preferably heated to 80 to 140 ° C., particularly 90 to 120 ° C., and cured. The heating time at this time may be about 0.5 to 3 minutes.

  The thickness of the anchor coat layer is preferably 0.1 to 1 μm, more preferably 0.1 to 0.5 μm. Thereby, it can be set as the anchor coat layer excellent in the absorbability of the electroless-plating pretreatment agent.

As described above, the anchor coat layer of the present invention is excellent in absorbability of the electroless plating pretreatment agent, so that the electroless plating pretreatment agent is prevented from sagging or spreading on the anchor coat layer. can do. Specifically, when 1 μl of the electroless plating pretreatment agent is dropped on the anchor coat layer, the spreading rate of the electroless plating pretreatment agent is preferably 0.1 to ³ μm ² / sec, more preferably 0. 5 to ² μm ² / sec. In addition, the spreading speed of the electroless plating pretreatment agent can be measured by the method described in Examples described later.

  The transparent substrate on which the composition is applied may be a substrate having transparency (particularly for visible light). Examples of the material include polyester (eg, polyethylene terephthalate (PET), polyethylene naphthalate). (PEN), polybutylene terephthalate), acrylic resin (eg, polymethyl methacrylate (PMMA)), polycarbonate (PC), polystyrene, cellulose triacetate, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene, ethylene-vinyl acetate A polymer, polyvinyl butyral, a metal ion crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane and the like can be mentioned. Among these, PET, PEN, PC, and PMMA, which are less transparent due to processing (heating, solvent, bending) and are highly transparent, are preferable.

  The thickness of the transparent substrate varies depending on the use of the electromagnetic shielding light-transmitting window material and the like, but is usually in the range of 1 μm to 5 mm, particularly preferably in the range of 10 μm to 1 mm.

(Mesh-shaped pretreatment layer forming process)
Next, in the method of the present invention, 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 is printed on the anchor coat layer in a mesh shape. The step of forming a mesh-shaped pretreatment layer is performed.

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

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

  Next, the azole compound used in the electroless plating pretreatment agent includes imidazole, oxazole, thiazole, selenazole, pyrazole, isoxazole, isothiazole, triazole, oxadiazole, thiadiazole, tetrazole, oxatriazole, thia Examples include triazole, benzazole, 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 with the azole compound, for example, 0.1 to 10 mol of silane coupling agent is mixed with 1 mol of azole compound at 80 to 200 ° C. for 5 minutes to It is preferable to react for 2 hours. 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. The 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 in the pretreatment agent for electroless plating exhibits a catalytic effect capable of selectively depositing and growing a metal such as copper or aluminum in the electroless plating treatment. Specifically, it is preferable to use a compound containing a metal atom such as palladium, silver, platinum, and gold because high catalytic activity is obtained. Examples of the compound include chlorides, hydroxides, oxides, sulfates, ammonium salts, and the like of the metal atom, and palladium compounds, particularly palladium chloride is preferable.

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

  Moreover, it is preferable that the said electroless-plating pretreatment agent contains the organic solvent. Specifically, as the organic solvent, a solvent belonging to the fourth class of first petroleums and a solvent belonging to the fourth class of second petroleums stipulated in the Fire Service Law are suitable.

  Examples of the solvent belonging to the first petroleums include toluene, ethyl acetate, isobutyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, isopropanol, and the like. Examples of the solvent belonging to the second type of second petroleum include xylene, n-butyl acetate, cellosolve, cellosolve acetate, n-butanol, isobutanol, and cyclohexanone. These may be used individually by 1 type, and 2 or more types may be mixed and used for them. These organic solvents can ensure excellent adhesion between the anchor coat layer and the transparent substrate even if the organic solvent contained in the printed electroless plating pretreatment agent is absorbed by the anchor coat layer. it can.

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

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

  In order to print the electroless plating pretreatment agent on the anchor coat layer, a printing method such as gravure printing, flexographic printing, gravure offset printing, screen printing, inkjet printing, electrostatic printing, or the like can be used. In particular, gravure printing and gravure offset printing are suitable for thinning. 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 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.

  The line width of the mesh-like (including lattice-like) pretreatment layer is generally 20 μm or less, preferably 5 to 15 μm, and 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 pretreatment layer can be an arbitrary shape such as a circle, an ellipse, or a square (quadrangle, hexagon), but is generally a square, and particularly preferably a square. . The lines are net-like, but are preferably grid-like.

  The pretreatment layer has a thickness of 0.01 to 2 μm, preferably 0.05 to 0.5 μm. Thereby, high adhesiveness with an anchor coat layer and a metal conductive layer is securable.

(Mesh-shaped metal conductive layer forming process)
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, 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 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.

  The 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 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 a transparent substrate having a pretreatment 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 metal conductive layer in a mesh shape (including a lattice shape) 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 metal conductive layer can be any shape such as a circle, an ellipse, and a square (quadrangle, hexagon), but is generally a square, and is particularly preferably a square. . The lines are net-like, but are preferably grid-like.

  The thickness of the metal conductive layer is preferably 2 to 10 μm, more preferably 2 to 5 μm.

  In the method of the present invention, after the step of forming the mesh-shaped metal conductive layer, an electroplating process may be performed to form a metal plating layer on the metal conductive layer.

  The material used for the electroplating treatment is not particularly limited as long as the metal plating layer has an excellent electromagnetic wave shielding effect, but for example, copper, nickel, chromium, zinc, tin, silver, gold, etc. A metal 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, a sufficient electromagnetic wave shielding effect may not be provided. On the other hand, when the thickness exceeds 10 μm, the electroplating layer also extends in the width direction, so that the line width increases and the metal conductive layer May have a low aperture ratio.

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

  Further, the mesh-like metal conductive layer or electroplating layer may be subjected to blackening treatment, for example, oxidation treatment of metal film, black plating of chrome alloy, etc., application of black or dark color ink, etc. be able to.

  The electromagnetic wave shielding light-transmitting window material obtained by the first method of the present invention described above contains an electroless plating pretreatment agent when the anchor coat layer formed on the transparent substrate contains a predetermined synthetic resin. Thus, printing can be performed with high accuracy without causing sagging, repelling, and the like. This makes it possible to easily form a mesh-shaped pretreatment layer with uniform line width and thickness and excellent dimensional accuracy (that is, there is almost no difference from the design dimension). A shape with excellent dimensional accuracy can be obtained. Therefore, the electromagnetic wave shielding light transmitting window material obtained by the method of the present invention is excellent in electromagnetic wave shielding properties and light transmission properties.

  Next, the second manufacturing method of the present invention will be described. The second production method of the present invention is the same as the first production method described above except that an electroless plating pretreatment agent containing a composite metal oxide and / or a composite metal oxide hydrate and a binder resin is used. Can be implemented.

  Also in the second method of the present invention, as in the first method described above, the anchor coat layer is excellent in absorbability of the electroless plating pretreatment agent by including the synthetic resin. Therefore, the electroless plating pretreatment agent can be smoothly printed on the anchor coat layer with a size and shape almost as designed. Therefore, it is possible to form a fine mesh-shaped pretreatment layer having a small line width. Furthermore, in the electroless plating pretreatment agent, the composite metal oxide and the composite metal oxide hydrate are excellent in dispersibility, and these are uniformly highly dispersed and fixed during printing, so that the electroless plating pretreatment agent is almost designed. It becomes possible to print in the shape of street dimensions. Therefore, it is possible to accurately form a mesh-shaped pretreatment layer having a fine pattern free from streaking and fogging. By performing an electroless plating process on such a mesh-shaped pretreatment layer, it is possible to form a fine mesh-shaped metal conductive layer having a small line width.

  The second production method of the present invention is the same as the first production method described above except that an electroless plating pretreatment agent containing a composite metal oxide and / or a composite metal oxide hydrate and a binder resin is used. Can be implemented. Therefore, the step of forming the anchor coat layer and the step of forming the mesh-like metal conductive layer can be performed in the same manner as in the first method described above, and thus the description thereof will be omitted. The process of forming a mesh-like pretreatment layer by printing an electroless plating pretreatment agent containing a composite metal oxide and / or a composite metal oxide hydrate and a binder resin in a mesh form will be described. .

(Mesh-shaped pretreatment layer forming process)
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 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)

(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.

The specifically as a composite metal oxide _{hydrate, PdSiO 3, Ag 2 SiO 3} , PdTiO 3, hydrates of such Ag ₂ TiO _3, PdZrO ₃ and Ag ₂ TiO ₃ and the like.

  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.

Further, as the composite metal oxide, (for M ^1, M ² and X, the formula (I) as _{^{synonymous) M 1 X · M 2 O}} 3 as represented by is preferably used.

  The average particle diameter of the composite metal oxide and the composite metal oxide hydrate used in the pretreatment agent for electroless plating 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 diameter of the composite metal oxide and the composite metal oxide hydrate is determined by measuring the composite metal oxide or the composite metal oxide hydrate with an electron microscope (preferably a transmission electron microscope). The observation is performed at a magnification of about 1 million times, and the number-average value of the area equivalent circle diameter of at least 100 particles is obtained.

  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 binder resin. preferable. 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.

  The electroless plating pretreatment agent includes a binder resin. Thereby, the adhesiveness with the anchor coat layer and metal conductive layer of a pretreatment layer can be improved, it becomes difficult to peel a pretreatment layer, and it becomes possible to form a metal conductive layer more accurately.

  The binder resin is not particularly limited as long as it can ensure adhesion with the anchor coat layer and the metal conductive layer. Preferred examples of the binder resin include acrylic resins, polyester resins, polyurethane resins, vinyl chloride resins, and ethylene vinyl acetate copolymer resins. Of these, polyester resins and polyurethane resins, particularly polyester resins are preferred. According to these, high adhesiveness with a transparent base material and a metal conductive layer is obtained, and a metal conductive layer can be accurately formed on a pretreatment layer. These binder resins may be used alone or in combination of two or more.

  Examples of the polyester resin as the binder resin include those described above as the synthetic resin used for the anchor coat layer.

  The electroless plating pretreatment agent preferably contains an active hydrogen-containing group as the binder resin, and further contains a polyisocyanate having at least two isocyanate groups. By using such a cured layer of the electroless plating pretreatment agent as the electroless plating pretreatment layer, the printing accuracy of the electroless plating pretreatment agent can be further improved.

  The content of the binder 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.

  The electroless plating pretreatment agent may further contain inorganic fine particles. By containing the inorganic fine particles, the printing accuracy can be improved, and a metal conductive layer with higher accuracy can be formed. Preferred examples of the inorganic fine particles include silica, calcium carbonate, alumina, talc, mica, glass flake, metal whisker, ceramic whisker, calcium sulfate whisker, and smectite. These may be used individually by 1 type, and may mix and use 2 or more types.

  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 the average particle size exceeds 5 μm, streaks and fog may easily occur. There is.

  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 binder 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 metal conductive layer with higher accuracy. As the thixotropic agent, 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 binder 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 base material 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 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 binder 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 pre-processing agent containing binder resin and a black coloring agent can be performed easily.

  Moreover, it is preferable that the said electroless-plating pretreatment agent contains the organic solvent. Specifically, as the organic solvent, a solvent belonging to the fourth class of first petroleums and a solvent belonging to the fourth class of second petroleums stipulated in the Fire Service Law are suitable.

  Examples of the solvent belonging to the first petroleums include toluene, ethyl acetate, isobutyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, isopropanol, and the like. Examples of the solvent belonging to the second type of second petroleum include xylene, n-butyl acetate, cellosolve, cellosolve acetate, n-butanol, isobutanol, and cyclohexanone. These may be used individually by 1 type, and 2 or more types may be mixed and used for them. These organic solvents can ensure excellent adhesion between the anchor coat layer and the transparent substrate even if the organic solvent contained in the printed electroless plating pretreatment agent is absorbed by the anchor coat layer. it can.

  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, a mesh-shaped pretreatment layer is formed on the transparent substrate by printing the above-described electroless plating pretreatment agent on the transparent substrate in a mesh shape. Thereby, a pretreatment layer having a desired fine pattern can be formed by a simple method.

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

  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 formability may not be obtained. The drying time for heat drying after coating is preferably 5 seconds to 5 minutes.

  In addition, since it is the same as that of the method mentioned above about the method of printing an electroless-plating pretreatment agent on a transparent base material, and the shape of the pattern in a mesh-shaped pretreatment layer, detailed description is abbreviate | omitted here.

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

  In the second method of the present invention, after the step of forming the mesh-like pretreatment layer on the transparent substrate as described above, before the step of forming the mesh-like metal conductive layer, the pretreatment layer It is preferable to carry out a reduction treatment step. Reduction treatment reduces the metal species contained in the composite metal oxide and composite metal oxide hydrate that are electroless plating catalysts contained in the pretreatment layer, and only the metal species that are active components are in the form of ultrafine particles. Can be deposited uniformly. Since the metal species thus reduced and deposited have high catalytic activity and are stable, the adhesion between the pretreatment layer and the anchor coat layer and the deposition rate of electroless plating can be improved, and further the composite The amount of metal oxide and composite metal oxide hydrate used can be reduced.

  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. Specifically, (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. For example, a gas phase reduction method in which is contacted with a reducing gas is preferably used.

  In the liquid phase reduction method, as a method of processing using a solution containing a reducing agent, specifically, a method of immersing the transparent substrate on which the pretreatment layer is formed in a solution containing a reducing agent, the transparent group A method of spraying a solution containing a reducing agent on the surface of the material on which the pretreatment layer has been formed is 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, In addition, 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, the treatment using a solution containing a reducing agent includes a high reduction property of the composite metal oxide and the composite metal oxide hydrate contained in the pretreatment layer. It is preferable to use a method in which the transparent substrate on which the treatment layer is formed is immersed 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.

  The electromagnetic wave shielding light-transmitting window material obtained by the second method of the present invention described above contains an electroless plating pretreatment agent when the anchor coat layer formed on the transparent substrate contains a predetermined synthetic resin. Thus, printing can be performed with high accuracy without causing sagging, repelling, and the like. This makes it possible to easily form a mesh-shaped pretreatment layer with uniform line width and thickness and excellent dimensional accuracy (that is, there is almost no difference from the design dimension). A shape with excellent dimensional accuracy can be obtained. Therefore, the electromagnetic wave shielding light transmitting window material obtained by the method of the present invention is excellent in electromagnetic wave shielding properties and light transmission properties.

  The electromagnetic wave shielding light-transmitting window material manufactured by the first method and the second method of the present invention described above has a high aperture ratio as described above, and thus has excellent light transmittance, and further prevents the moire phenomenon. Since it has excellent shielding properties, it is particularly useful as a front filter of a PDP (plasma display panel), a window material (for example, a sticking film) of a building requiring an electromagnetic wave shield such as a hospital. When the electromagnetic wave shielding light-transmitting window material having the antiglare layer is used as a PDP (plasma display panel), the antiglare layer is disposed on the observer side on the transparent substrate from the viewpoint of visibility. It is preferred to be used as is.

Example 1
1. Formation of Anchor Coat Layer After applying an anchor coat layer forming composition having the following composition by gravure coating on a PET film (thickness 250 μm), the anchor coat layer (thickness) is heated at 100 ° C. for 1 minute. 0.2 μm) was formed.

The composition of the anchor coat layer forming composition;
100 parts by mass of polyester resin (Byron (registered trademark) 670, manufactured by Toyobo Co., Ltd .; number average molecular weight Mn 20 × 10 ³ , glass transition temperature (Tg) 7 ° C.)
15 parts by mass of polyisocyanate (CAT-10L, manufactured by Toyo Morton Co., Ltd.)
Methyl ethyl ketone / toluene = 1/1 (mass ratio) 900 parts by mass

2. Formation of mesh-shaped pretreatment layer Reaction product obtained by mixing imidazole with γ-glycidoxypropyltrimethoxysilane at a molar ratio of 1: 1 and reacting for 1 hour and 100 minutes Palladium chloride was added to an aqueous solution containing 5 wt% of the product while stirring at 25 ° C. to prepare a solution having a palladium chloride concentration of 10 g / L. This was diluted 100 volume times with n-butanol to prepare a pretreatment agent having a palladium chloride concentration of 100 mg / L.

  Next, the pretreatment agent was patterned on the anchor coat layer produced above by gravure printing, and then dried at 120 ° C. for 5 minutes to form a mesh-like pretreatment layer on the PET film. As the gravure printing plate, a mold in which grooves having a width of 16 μm and a depth of 6 μm were formed at intervals of 200 μm was used.

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, Reduction treatment was performed.

3. 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 produce a mesh-like metal conductive layer (thickness: 2 μm) to obtain an electromagnetic wave shielding light transmitting window material.

(Examples 2 and 3)
An electromagnetic wave shielding light transmissive window material was manufactured in the same manner as in Example 1 except that the thickness of the anchor coat layer was 0.6 μm and 1.0 μm, respectively.

(Comparative Example 1)
An electromagnetic wave shielding light transmitting window material was manufactured in the same manner as in Example 1 except that the anchor coat layer was not formed.

(Comparative Example 2)
An electromagnetic wave shielding light transmitting window material was produced in the same manner as in Example 1 except that the anchor coat layer forming composition having the following composition was used.

The composition of the anchor coat layer forming composition;
100 parts by mass of polyester resin (Byron (registered trademark) 103, manufactured by Toyobo Co., Ltd .; number average molecular weight Mn23 × 10 ³ , glass transition temperature (Tg) 47 ° C.)
15 parts by mass of polyisocyanate (CAT-10L, manufactured by Toyo Morton Co., Ltd.)
Methyl ethyl ketone / toluene = 1/1 (mass ratio) 900 parts by mass

(Comparative Examples 3 and 4)
An electromagnetic wave shielding light-transmitting window material was manufactured in the same manner as in Comparative Example 2 except that the thickness of the anchor coat layer was 0.6 μm and 1.0 μm, respectively.

(Evaluation)
1. Spread rate of pretreatment agent in anchor coat layer For the anchor coat layers prepared in Examples and Comparative Examples, the spread rate of the pretreatment agent was measured according to the following procedure.

On the anchor coat layer, 1 μl of the pretreatment agent used in Example 1 is dropped by a microsyringe, and the area of the portion in contact with the anchor coat layer of the droplet 10 seconds after dropping is determined by a suitable contact angle. The spreading speed [μm ² / sec] was determined by calculating and dividing the area by 10 [sec]. The results are shown in Table 1.

  In Comparative Example 1, the spreading speed of the pretreatment agent was measured for the PET film according to the same procedure as described above.

2. Pattern shape of mesh-like pretreatment layer The width of each mesh-like pretreatment layer produced in the examples and comparative examples is a microscope (manufactured by Keyence), and the thickness of the mesh-like pretreatment layer is the surface roughness meter (Mitutoyo). The product was measured at four locations, and the average value was calculated. The results are shown in Table 1.

  As shown in Table 1, in Examples 1 to 3 using a polyester resin having a glass transition temperature of 20 ° C. or less, it is understood that the spreading speed of the pretreatment agent is low and the pretreatment agent can be printed with excellent accuracy.

101 transparent substrate,
102 anchor coat layer,
103 mesh-like pretreatment layer,
104 Mesh-like metal conductive layer.

Claims (11)

A step of forming an anchor coat layer by applying a composition containing a synthetic resin having a glass transition temperature of 20 ° C. or less to the surface of a transparent substrate and curing the composition;
On the anchor coat layer, a mixture or reaction product of a silane coupling agent and an azole compound, and an electroless plating pretreatment agent containing a noble metal compound are printed in a mesh shape to form a mesh-shaped pretreatment layer. And a process of
And a step of forming a mesh-shaped metal conductive layer on the pretreatment layer by electroless plating treatment.   The method for producing an electromagnetic wave shielding light transmitting window material according to claim 1, wherein the synthetic resin is a polyester resin.   The electromagnetic shielding light-transmitting window material according to claim 1 or 2, wherein the synthetic resin has a group containing active hydrogen, and the composition further contains a polyisocyanate having at least two isocyanate groups. Manufacturing method.   The method for producing an electromagnetic wave shielding light transmissive window material according to claim 3, wherein the content of the polyisocyanate is 5 to 20 parts by mass with respect to 100 parts by mass of the synthetic resin.   The thickness of the said anchor coat layer is 0.1-1 micrometer, The manufacturing method of the electromagnetic wave shielding light transmission window material of any one of Claims 1-4 characterized by the above-mentioned. The spreading rate of the electroless plating pretreatment agent is 0.1 to ³ µm ² / sec when 1 µl of the electroless plating pretreatment agent is dropped on the anchor coat layer. 6. The method for producing an electromagnetic wave shielding light transmissive window material according to any one of 5 above.   The said silane coupling agent is an epoxy group containing silane compound, The manufacturing method of the electromagnetic wave shielding light transmission window material of any one of Claims 1-6.   The method for producing an electromagnetic wave shielding light transmitting window material according to any one of claims 1 to 7, wherein the azole compound is imidazole.   The electromagnetic wave shielding light transmissive window material according to any one of claims 1 to 8, wherein the noble metal compound is a compound containing at least one metal atom selected from the group consisting of palladium, silver, platinum and gold. Manufacturing method.   The electromagnetic wave shielding light-transmitting window material according to any one of claims 1 to 9, wherein the electroless plating pretreatment agent is printed in a mesh shape on the anchor coat layer and then dried at 80 to 160 ° C. Method.   The electromagnetic wave shielding light transmission window material obtained by the method of any one of Claims 1-10.

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