JP6801755B2 - Conductive sheet - Google Patents

Description

The present invention relates to a conductive sheet suitable for conducting conduction between the display surface operation surface of the display surface operation panel and the back surface thereof.

As a conventional electromagnetic wave shielding tape, a conductive sheet in which a conductive adhesive layer is provided on one side of a metal foil such as aluminum or copper has been proposed (Patent Document 1). In order to prevent such a conductive sheet from being short-circuited due to contact with other conductors, an insulating resin layer is formed on the surface of the conductive sheet on which the conductive adhesive layer is not formed. By laminating a polyethylene terephthalate (PET) film, an improvement has been made to impart insulation to one side of the conductive sheet. Further, a release film is attached to the conductive adhesive layer to improve the handleability.

By the way, in recent years, a display surface operation panel (so-called touch panel) has been applied to smartphones, portable game machines, ticket vending machines, etc., and a conductive sheet is used to conduct conduction from the display surface operation surface to the back surface thereof. ing. An insulating resin film is laminated on one side of such a conductive sheet in order to prevent a short circuit from occurring due to unintended contact with another conductor such as a metal housing. Insulation is imparted to one side of the surface by squeezing. When conducting continuity from the display surface operation surface of the display surface operation panel to the back surface of the display surface operation panel with such a conductive sheet, the outer edge of the display surface operation panel is wrapped so that the insulating resin film of the conductive sheet is on the outside. Is being tried. In this case, in order to improve the quality of the image visually recognized through the display surface operation panel or to prevent the deterioration of the image visibility, the insulating resin film of the conductive sheet has a black frame. Attempts have been made to color itself black and to further form a black printing layer on the insulating resin film.

Japanese Unexamined Patent Publication No. 62-227985

However, when the conductive sheet of Patent Document 1 is passed through a coater or the release film is peeled off from the conductive sheet, the metal layer is easily plastically deformed as compared with the PET film, while the PET film is easily elastically deformed, so that it is conductive. There is a problem that the sex sheet tends to be curled. Further, when the conductive sheet is attached to the display surface operation panel so as to wrap the outer edge of the display surface operation panel, it cannot be said that the conductive sheet has sufficient followability to the steps and corner shapes of the affixed portion. Therefore, there is also a problem that it is easily peeled off and the required shape retention cannot be obtained.

An object of the present invention is to solve the above problems of the prior art, in which a conductive adhesive layer is laminated on one side of a base base material and a light-shielding insulating layer is laminated on the other side of the base base material. It is an object of the present invention to impart difficulty in curling, good shape stability, and shape followability to the conductive sheet.

The present inventor has found that the above object can be achieved by adopting a laminate in which the same type of metal layer is laminated on both sides of a resin film as a base base material which is a central portion in the thickness direction of the conductive sheet. The present invention has been completed.

That is, the present invention is a conductive sheet in which a conductive adhesive layer is laminated on one side of a base base material and a light-shielding insulating layer is laminated on the other side of the base base material, and the base base material is a resin film. Provided is a conductive sheet having a structure in which the same type of metal layer is formed on both sides of the above.

In this case, insulation levels of the light-shielding insulating layer surface of the conductive sheet has a surface resistivity of preferably 1.0 × 10 ⁸ Ω / □ or more, the level of the light-shielding property is preferred and glossiness than 80% optically The concentration is 1 or more.

Further, in the present invention, the front surface electrode provided on the front surface outer edge portion of the display surface operation panel and the back surface electrode provided on the back surface outer edge portion are arranged so as to wrap the outer edge portion of the display surface panel. Provided is an image display module having the display surface operation panel connected by the conductive sheet of the above and an image display panel operated by the display surface operation panel.

The conductive sheet of the present invention in which a conductive adhesive layer is laminated on one side of a base base material and a light-shielding insulating layer is laminated on the other side of the base base material can be used as a base base material on both sides of a resin film of the same type of metal. Use one that has a layered structure. Therefore, even if tension is applied to the conductive sheet, the metal layers on both sides of the resin film show the same elongation rate, so that the occurrence of curl can be greatly suppressed. In addition, since metal layers are arranged on both sides of the insulating film, it can be attached with good shape followability to changing shapes such as curved surfaces and refracted parts (corners), and also has good shape retention. Are better.

Further, when the surface resistance of the insulating level 1.0 × 10 ⁸ Ω / □ or more light-shielding insulating layer surface of the light shielding insulating layer, is possible to suppress the occurrence of short circuit due to contact with other conductors It will be possible. Further, when the light-shielding property has a glossiness of 80% or less and an optical density of 1 or more, a matte black frame can be provided on the outer edge of the display surface operation panel, and the image viewed through the display surface operation panel can be provided. The visibility of the image can be greatly improved.

FIG. 1 is a cross-sectional view of the conductive sheet of the present invention. FIG. 2 is a cross-sectional view of the conductive sheet of the present invention. FIG. 3 is a cross-sectional view of the conductive sheet of the present invention.

Hereinafter, the conductive sheet of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of the conductive sheet 100 of the present invention. In this conductive sheet 100, a conductive adhesive layer 20 is formed on one side of a base base material 10, and a light-shielding insulating layer 30 is formed on the other side. Has a structure that is

<Base base material>
The conductive sheet 100 of the present invention is characterized in that the base base material 10 has a structure in which the same type of metal layers 2 and 3 are laminated on both surfaces of the resin film 1. As a result, it is possible to greatly suppress the occurrence of curl in the conductive sheet, and it is possible to impart good shape followability and shape stability to the conductive sheet.

As the resin film 1 constituting the base base material 10, the resin film used as the base film of the conductive sheet can be preferably applied. Examples of such a resin film include polyester film, polyolefin film, polyamide film, polyurethane film, polystyrene film and the like. Among them, a polyester film, particularly a polyethylene terephthalate film, can be preferably applied from the viewpoints of availability, mechanical strength, heat resistance, cost, rust resistance and the like.

The layer thickness of the resin film 1 constituting the base base material 10 is preferably 5 to 20 μm in order to maintain the mechanical strength of the conductive sheet and to ensure good shape followability and shape stability. More preferably, it is 7 to 15 μm.

As the metal layers 2 and 3 constituting the base base material 10, the metal layers used in the conventional conductive sheet can be applied. Examples of such metal layers 2 and 3 include aluminum, copper, nickel, gold, silver and the like. Among these, aluminum can be preferably applied from the viewpoints of availability, mechanical strength, heat resistance, cost, rust resistance and the like.

The thickness of the metal layer 2 on the conductive adhesive layer 20 side and the metal layer 3 on the light-shielding insulating layer 30 side maintains the mechanical strength of the conductive sheet, and ensures good shape followability and shape stability. Therefore, each is preferably 5 to 20 μm, more preferably 7 to 15 μm.

The ratio of the thickness [Mt1] of the metal layer 2 on the conductive adhesive layer 20 side, the thickness [Bt] of the resin film 1 and the thickness [Mt2] of the metal layer 3 on the light-shielding insulating layer 30 side is shape-following. From the viewpoint of achieving both shape retention and shape retention, preferably [Mt1]: [Bt]: [Mt2] = 0.25 to 4: 1: 0.25 to 4, more preferably 0.4 to 2.4: It is 1: 0.4 to 2.4.

The metal layers 2 and 3 can be formed on the resin film 1 by a conventional method. For example, a metal foil is formed on the resin film 1 as a metal layer via an adhesive layer (not shown) formed from a dry adhesive such as a polyester adhesive or a polyurethane adhesive containing an isocyanate-based cross-linking agent or the like. A method of laminating, a method of forming metal layers 2 and 3 by subjecting both sides of the resin film 1 to electrolytic metal plating and further performing electrolytic metal plating, and a method of forming metal layers 2 and 3 on both sides of the resin film 1 by a vacuum vapor deposition method. A method of laminating 3 and the like can be mentioned. Above all, from the viewpoint of high mass productivity and low manufacturing cost, a method of laminating a metal layer via an adhesive layer can be preferably applied.

Further, if the linear expansion coefficient [ppm / ° C.] of the resin film 1 constituting the base base material 10 is too large, curling tends to occur, and if it is too small, the laminated structure tends to become unstable in a thermal environment. Since there is a concern that delamination may occur, the temperature is preferably 15 to 100 ppm / ° C, more preferably 20 to 70 ppm / ° C.

The coefficient of linear expansion [ppm / ° C.] of the metal layers 2 and 3 is preferably 12 to 25 ppm / ° C., more preferably 16 to 23 ppm / ° C. from the viewpoint of the stability of the laminated structure with the resin film 1. ..

If the difference between the coefficient of linear expansion of the resin film 1 and the coefficient of linear expansion of the metal layers 2 and 3 is too large, curling tends to occur. Therefore, it is preferably 40 ppm / ° C or less, more preferably 25 ppm / ° C or less. Is.

If the tensile elastic modulus [GPa] of the resin film 1 constituting the base base material 10 according to JIS K7113 is too small, it tends to curl easily, and if it is too large, the shape followability tends to be impaired. It is 3 to 15 GPa, more preferably 2 to 7 GPa.

Further, the tensile elastic modulus [GPa] of the metal layers 2 and 3 according to JIS K7113 tends to be easily curled if it is too small, and tends to impair shape followability if it is too large. Therefore, it is preferably 45 to 200 GPa. It is preferably 75 to 130 GPa.

If the difference in tensile elastic modulus between the resin film 1 constituting the base base material 10 and the metal layers 2 and 3 due to JIS K7113 is too large, curling tends to occur. Therefore, it is preferably 100 GPa or less, more preferably. It is 80 GPa or less.

<Light-shielding insulating layer>
The light-shielding insulating layer 30 constituting the conductive sheet 100 of the present invention is a layer that imparts light-shielding property and insulating property to the conductive sheet 100. The insulation level of the light-shielding insulating layer 30 the surface of the conductive sheet 100, since too low occurrence of a short circuit is concerned, the surface resistance value is preferably 1.0 × 10 ⁸ Ω / □ or more, more It is preferably 1.0 × 10 ¹⁰ Ω / □ or more.

Further, the light-shielding property level of the light-shielding insulating layer 30 is such that the glossiness according to JIS Z8741 (incident angle 60 °) is preferably 80% or less, more preferably 40% or less in order to improve the visibility of the image. Moreover, the optical density according to JIS K7605 is preferably 1 or more, more preferably 1.2 or more, and even more preferably 1.4 or more.

As the layer thickness of the light-shielding insulating layer 30, if it is too thin, the intended optical characteristics tend to be impaired, and if it is too thick, cracks tend to occur. Therefore, it is preferably 3 to 15 μm, more preferably 5 to 11 μm. Is.

Such a light-shielding insulating layer 30 can have various configurations in which the surface resistance value, glossiness, and optical density of the surface thereof are within the above ranges. For example, as shown in FIG. 1, a configuration in which it is a single-layer black resin layer formed of an insulating resin colored with a black colorant, and as shown in FIGS. 2 and 3, it is colored with a black colorant. Examples thereof include a configuration including a black resin layer 30a formed of an insulating resin, an insulating primer layer 30b formed on one surface thereof, and a matte varnish layer 30c.

Examples of the insulating resin of the black resin layer constituting the light-shielding insulating layer 30 include ethylene-α-olefin copolymers such as polyethylene, polypropylene and ethylene-propylene copolymers, polymethylpentene, polyvinyl chloride and poly. Fluorine-based polymers such as vinylidene chloride, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyvinyl acetal, polyvinylidene fluoride and polytetrafluoroethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polystyrene, poly Acrylonitrile, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer (ABS) resin, polyphenylene-ether copolymer (PPE) resin, modified PPE resin, aliphatic polyamides, aromatic polyamides, polyimide, polyamide Polymethacrylic acid esters such as imide, polymethacrylic acid, polymethacrylic acid methyl ester, polyacrylic acids, polycarbonate, polyphenylene sulfide, polysulfone, polyether sulfone, polyether nitrile, polyether ketone, polyketone, liquid crystal polymer, silicone resin , Polymeric resins such as ionomers. In addition, styrene-butadiene block copolymer or its hydrogenated product, styrene-isoprene block copolymer or its hydrogenated product, styrene-based thermoplastic elastomer, olefin-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer, polyester-based thermal Examples thereof include thermoplastic elastomers such as plastic elastomers, polyurethane-based thermoplastic elastomers, and polyamide-based thermoplastic elastomers. Further, crosslinked rubber, epoxy resin, phenol resin, polyimide resin, unsaturated polyester resin, diallyl phthalate resin and the like can be mentioned. Specific examples of the crosslinked rubber include natural rubber, acrylic rubber, butadiene rubber, isoprene rubber, styrene-butadiene copolymer rubber, nitrile rubber, hydrogenated nitrile rubber, chloroprene rubber, ethylene-propylene copolymer rubber, and chlorinated polyethylene rubber. Examples thereof include thermosetting resins such as chlorosulfonated polyethylene rubber, butyl rubber, halogenated butyl rubber, fluororubber, urethane rubber, and silicone rubber. It is also possible to apply a photocurable resin.

Examples of the black colorant include known black dyes such as aniline black, carbon black, and titanium black, and black pigments. If the average particle size of these colorants is too small, it tends to be difficult to uniformly mix them with the insulating resin during manufacturing, and if it is too large, the smoothness of the light-shielding insulating layer 30 is lowered. It is preferably 10 to 500 nm, more preferably 50 to 100 nm. Further, if the content of the black colorant in the black resin layer is too small, the intended optical characteristics tend not to be obtained, and if it is too large, the adhesion to the adjacent layer may be lowered or the black colorant may fall off. Since there is concern, it is preferably 10 to 40% by mass, more preferably 15 to 30% by mass.

In addition, examples of the insulating primer layer 30b shown in FIG. 2 include those in which the insulating resin exemplified in the black resin layer is mixed with a filler such as silica in order to prevent blocking, if necessary.

If the thickness of the insulating primer layer 30b is too thin, the intended insulating property tends not to be obtained, and if it is too thick, the intended shape retention property tends not to be obtained. Therefore, the thickness is preferably 2 to 10 μm, more preferably. It is 3 to 7 μm.

The matte varnish layer 30c shown in FIG. 3 has an average particle size of 0.1 to 10 μm of silica, barium sulfate, calcium carbonate, polyethylene beads, polystyrene beads, benzoguanamine beads, etc. in the insulating resin exemplified by the black resin layer. In order to achieve a well-balanced matte appearance and good coating strength, the filler is preferably contained in an amount of 30 to 80% by mass to form a film.

If the thickness of the matte varnish layer 30c is too thin, the intended insulating property tends not to be obtained, and if it is too thick, the intended shape retention and optical characteristics tend not to be obtained. Therefore, the thickness is preferably 2 to 10 μm. It is preferably 3 to 7 μm.

When the light-shielding insulating layer 30 is a single-layer black resin layer as shown in FIG. 1, it is preferable to use aniline black as the black colorant from the viewpoint that the black colorant itself is insulating. .. Further, in the case of a two-layer structure as shown in FIG. 2 or 3, the black colorant of the black resin layer 30a may be aniline black, but there are an insulating primer layer 30b and a matte varnish layer 30c that ensure insulating properties. Therefore, carbon black, which itself exhibits conductivity, can be used as long as the effect of the present invention is not impaired.

<Conductive adhesive layer>
As the conductive adhesive layer 20 constituting the conductive sheet 100, the conductive adhesive layer of the conventional conductive sheet can be applied. For example, conductive particles such as carbon black and metal particles are mixed with the insulating resin exemplified in the black resin layer in an amount sufficient to ensure conductivity having a surface resistance value of 500 mΩ / □ or less to form a film. I can mention things.

If the thickness of the conductive adhesive layer 20 is too thin, the intended adhesiveness tends not to be obtained, and if it is too thick, the intended conductive characteristics tend not to be obtained. Therefore, the thickness is preferably 10 to 35 μm, more preferably. It is 15 to 25 μm.

<Manufacturing of conductive sheet>
The conductive sheet of the present invention can be produced by using a known method. For example, a dry adhesive such as a urethane adhesive containing an isocyanate curing agent is applied to one side of a resin film such as a PET film, a metal layer such as an aluminum foil is laminated, and then the dry adhesive is similarly applied to the other surface. By applying and laminating metal layers, a base base material having metal layers laminated on both sides is created. Next, the paint for the conductive pressure-sensitive adhesive layer is applied onto the release sheet and dried to form the conductive pressure-sensitive adhesive layer, on which the base base material is laminated. Subsequently, a black ink for forming a black resin layer is applied onto the base base material and dried to form a light-shielding insulating layer. As a result, the conductive sheet of FIG. 1 is obtained.

The conductive sheet of FIGS. 2 and 3 is basically manufactured in the same manner as the conductive sheet of FIG. 1, except that the black resin layer and the matte varnish layer or the insulating primer layer are respectively applied and dried to form a film. Can be done.

The conductive sheet of the present invention is preferably applied to an image display module in which the conductive portion is arranged on an undulating plane or an image display module in which the conductive portion is not present on the same plane. Can be done.

As an example of the former, an image display module arranged so as to connect a display panel such as a notebook computer to a board separately provided with an arbitrary bent portion and a step separated by a conductive sheet can be illustrated. it can. An image display module as exemplified by this notebook computer is also a part of the present invention.

Further, as an example of the latter, the front surface electrode provided on the front surface outer edge portion of the display surface operation panel such as a touch panel and the back surface electrode provided on the back surface outer edge portion are formed by a conductive sheet on the outer edge portion of the display surface operation panel. An image display module in which a display surface operation panel arranged and connected so as to wrap around the image display panel and an image display panel such as a liquid crystal display panel to be operated can be exemplified. This image display module is also a part of the present invention.

Example 1
3 g / 3 g of polyester resin (UE3220, Unitica Co., Ltd.) using an isocyanate-based curing agent (Coronate L, Nippon Polyurethane Industry Co., Ltd.) on one side of a 5 μm-thick PET film (Mylar, Teijin DuPont Film Co., Ltd.) The film was applied in m ² (converted to the amount of dry coating), and a 7 μm-thick soft aluminum foil (1030N-0 material, Nippon Polyurethane Industry Co., Ltd.) was laminated. Similarly, a 7 μm-thick soft aluminum foil (1030N-0 material, Nippon Foil Co., Ltd.) was laminated on the other surface of the PET film to prepare a base base material.

A conductive black adhesive (an acrylic adhesive containing 10% by mass of carbon black) is applied to the peeled PET film so as to have a dry thickness of 25 μm, and the film is dried to form a conductive black adhesive layer. The base base material prepared above was laminated on this conductive black adhesive layer.

Next, on this base base material, insulating black ink {aniline black (Tokyo Color Material Industry Co., Ltd.)
) Was dispersed in a polyester resin (Byron 200, Toyobo Co., Ltd.), and an ink (Dexerials Co., Ltd.)} was applied and dried to a dry thickness of 3 μm to form a light-shielding insulating layer. As a result, a conductive sheet having the configuration shown in Table 1 was obtained.

Example 2
The configuration shown in Table 1 is obtained by repeating the same operation as in Example 1 except that a 12 μm thick PET film (E5100, Toyobo Co., Ltd.) is used instead of the 5 μm thick PET film of the base base material. A conductive sheet was obtained.

Example 3
As a light-shielding insulating layer, an insulating primer layer (polyester resin (Polyester 200, Toyo Spinning Co., Ltd.)) having a thickness of 3 μm from the base base material side and a carbon black black ink layer formed on the resin {carbon black (MA8, Mitsubishi) Repeat the same operation as in Example 1 except for using a laminate with an ink (Dexerials America Corporation) in which Chemical Co., Ltd. is dispersed in a polyester resin (Byron 200, Toyo Spinning Co., Ltd.). Obtained a conductive sheet having the constitution shown in Table 1.

Example 4
As a light-shielding insulating layer, a carbon black black ink layer 3 μm thick from the base material side {carbon black (MA8, Mitsubishi Chemical Corporation) is dispersed in a polyester resin (Byron 200, Toyo Spinning Co., Ltd.) By repeating the same operation as in Example 1 except that a laminate of Dexerials America Corporation} and a 3 μm thick matte varnish layer (LG6620, Tokyo Ink Co., Ltd.) is used, the conductivity of the configuration shown in Table 1 is established. I got a sheet.

Comparative Example 1
As a light-shielding insulating layer, a carbon black black ink layer with a thickness of 3 μm {Ink in which carbon black (MA8, Mitsubishi Chemical Corporation) is dispersed in polyester resin (Byron 200, Toyo Spinning Co., Ltd.) (Dexerials America Corporation) } Was repeated except that the same operation as in Example 1 was repeated to obtain a conductive sheet having the configuration shown in Table 1.

Comparative Example 2
The urethane adhesive used in Example 1 was applied to the metal layer of the base base material before forming the carbon black black ink layer, and a 5 μm-thick PET film (Mylar, Teijin DuPont Film Co., Ltd.) was laminated. Later, by repeating the same operation as in Comparative Example 1 except for forming the carbon black black ink layer, a conductive sheet having the constitution shown in Table 1 was obtained.

Comparative Example 3
By repeating the same operation as in Comparative Example 2 except that a 12 μm-thick PET film (E5100, Toyobo Co., Ltd.) is used instead of the 5 μm-thick PET film sandwiched between the aluminum foils of the base base material. A conductive sheet having the configuration shown in Table 1 was obtained.

Comparative Example 4
As the base base material, a PET film having a thickness of 5 μm in which a soft aluminum foil is laminated via the adhesive used in Example 1 is used only on one side thereof, and the soft aluminum foil is not laminated directly on the base base material surface on which the soft aluminum foil is not laminated. Use a laminate with carbon black black ink layer {ink (Dexerials Co., Ltd.) in which carbon black (MA8, Mitsubishi Chemical Co., Ltd.) is dispersed in polyester resin (Byron 200, Toyo Spinning Co., Ltd.)}. Except for this, the same operation as in Comparative Example 1 was repeated to obtain a conductive sheet having the configuration shown in Table 1.

Comparative Example 5
The configuration shown in Table 1 is obtained by repeating the same operation as in Comparative Example 4 except that a 12 μm thick PET film (E5100, Toyobo Co., Ltd.) is used instead of the 5 μm thick PET film of the base base material. A conductive sheet was obtained.

Comparative Example 6
Instead of forming a conductive adhesive layer on the peeled PET film, the operation of Comparative Example Non-4 is performed except that a conductive non-woven fabric reinforced adhesive film (Sui-80-M30, Seiren Co., Ltd.) having a thickness of 30 μm is laminated. By repeating the process, a conductive sheet having the constitution shown in Table 1 was obtained.

Comparative Example 7
The configuration shown in Table 1 is obtained by repeating the same operation as in Comparative Example 6 except that a 12 μm thick PET film (E5100, Toyobo Co., Ltd.) is used instead of the 5 μm thick PET film of the base base material. A conductive sheet was obtained.

<Evaluation>
As described below, the obtained conductive sheet has "curl characteristics", "shape retention", "shape followability (repulsion)", "insulation (surface resistance value)", and "light shielding property" (light shielding property). Glossiness and optical density) ”was tested and evaluated. The results obtained are shown in Table 1.

"Curl characteristics"
The conductive sheet was cut into strips having a width of 15 mm and a length of 150 mm, and the release sheet on the conductive adhesive layer side of the test sample was peeled off at a speed of 1000 mm / sec in the 180 ° direction, and the generated curl was visually confirmed. .. When the curl generated was within one rotation, it was determined to be good, and when it exceeded one rotation, it was determined to be defective.

"Shape retention"
The conductive sheet was cut into strips with a width of 15 mm and a length of 50 mm, and the release sheet on the conductive adhesive layer side of the test sample was peeled off at a speed of 1000 mm / sec in the 180 ° direction, and light-shielding insulation was performed at the center of the sample. It was bent 90 ° toward the layer side, and it was visually confirmed whether the shape could be maintained for 10 seconds in that state. When the shape could be retained, it was determined to be good, and when the shape could not be retained, it was determined to be defective.

"Shape followability (repulsion)"
The peeling sheet on the conductive adhesive layer side of the test sample cut out from the conductive sheet into a rectangle having a length of 15 mm and a width of 10 mm is removed, and the long side thereof is wrapped around the thick portion of the aluminum plate having a thickness of 1 mm. And when it was pasted so as to cover the edge 1 mm of the surface of the aluminum plate, the rest was bent 90 ° and pasted on the back surface of the aluminum plate, and left in an environment of 80 ° C. and 95% RH for 72 hours, did peeling occur? Whether or not it was visually observed. The case where no peeling occurred was judged to be good, and the case where peeling occurred was judged to be defective.

"Insulation (surface resistance value)"
The surface resistance value of the surface of the light-shielding raw insulating layer of the conductive sheet was measured using an electric resistance measuring instrument (High Lester, Mitsubishi Analytech Co., Ltd.). In practice, it is required that at 1 × 10 ⁸ Ω / □ or more.

"Light-shielding property (glossiness and optical density)"
The glossiness of the surface of the light-shielding insulating layer of the conductive sheet was measured using a glossiness meter (Gloss Checker IG-320, HORIBA, Ltd.) according to JIS Z8741 (incident angle 60 °). Practically, it is required to be 80% or less. Further, the optical density on the surface of the light-shielding insulating layer was measured using an optical densitometer (reflection densitometer RT924, manufactured by Macbeth) according to JIS K7605. Practically, it is required to be 1.4 or more. Those satisfying both performances were judged to be good.

The conductivity of the conductive adhesive layers of the conductive sheets of Examples 1 to 4 and Comparative Examples 1 to 5 and the conductive non-woven fabric reinforced adhesive films of Comparative Examples 6 and 7 were cut into strips of 100 × 25 mm. The sample was attached so as to bridge the ends of two copper foils (1 × 25 × 100 mm) arranged in parallel with a distance of 50 mm, and used with an electric resistance measuring instrument (milliohm meter 4332B, Aguillent) 2 The resistance value between the copper foils was measured. As a result, all the samples showed a very low resistance value of 50 to 60 mΩ, which is much lower than 500 mΩ.

The conductive sheets of Examples 1 to 4 gave good results for all the evaluation items.

On the other hand, in the case of the conductive sheet of Comparative Example 1, since the light-shielding insulating layer was formed by using carbon black black ink showing conductivity without using the insulating black ink, the surface resistance value was low and it was practically used. It did not show satisfactory insulation.

Further, in the case of the conductive sheet of Comparative Example 2, the lower layer of the carbon black black ink layer is formed even though the light-shielding insulating layer is formed by using the carbon black black ink without using the insulating black ink. Since the insulating PET film was placed on the surface, good insulation was exhibited, but the curl characteristics were problematic due to the loss of symmetry in the thickness direction of the base substrate.

In the case of the conductive sheet of Comparative Example 3, since the resin film thickness of the base base material of the conductive sheet of Comparative Example 2 was increased from 5 μm to 12 μm, the symmetry in the thickness direction of the base base material was inferior to that of Comparative Example 2. As a result, there was a problem with shape followability.

In the case of the conductive sheets of Comparative Examples 4 and 5, since the base base material in which the aluminum foil is laminated on only one side is used, the shape followability is good, but the curl characteristics and the shape retention are improved. There was a problem.

In the case of the conductive sheets of Comparative Examples 6 and 7, since the non-woven fabric reinforced adhesive film is used as the conductive adhesive layer, there is no problem in the curl characteristics, but in each case, the base in which the aluminum foil is laminated on only one side. Since a base material is used, there are problems in shape retention and shape followability.

The conductive sheet of the present invention in which a conductive adhesive layer is laminated on one side of a base base material and a light-shielding insulating layer is laminated on the other side of the base base material can be used as a base base material on both sides of a resin film of the same type of metal. Use one that has a layered structure. Therefore, even if tension is applied to the conductive sheet, the metal layers on both sides of the resin film show the same elongation rate, so that the occurrence of curl can be greatly suppressed, and the curved surface, the refracted portion (corner portion), etc. It can be attached with good shape followability even for changing shapes, and it is also excellent in shape retention. Therefore, the conductive sheet of the present invention is used for manufacturing an image display module in which the conductive portion is arranged on an undulating plane, or an image display module in which the conductive portion is not present on the same plane. It is useful.

1 Resin film 2 Metal layer on the conductive adhesive layer side 3 Metal layer on the light-shielding insulating layer side 10 Base base material 20 Conductive adhesive layer 30 Light-shielding insulating layer 30a Black resin layer 30b Insulation primer layer 30c Matte varnish layer 100 Conductive sheet

Claims (20)

An image display module in which the outer edges of at least some of the members constituting the image display module are attached so as to be wrapped with a conductive sheet.
The conductive sheet is a conductive sheet in which a conductive adhesive layer is laminated on one side of a base base material and a light-shielding insulating layer is laminated on the other surface of the base base material, and the base base material is a resin film. An image display module, which is a conductive sheet having a structure in which the same type of metal layer is formed on both sides of the above. An image display module in which the outer edges of at least some of the members constituting the image display module are attached so as to be wrapped with a conductive sheet.
The conductive sheet is a conductive sheet in which a conductive adhesive layer is laminated on one side of a base base material and a light-shielding insulating layer is laminated on the other surface of the base base material, and the base base material is a resin film. An image display module which is a conductive sheet having a structure in which metal layers showing the same elongation rate are formed on both sides of the above. The base base material has a structure in which a conductive adhesive layer is laminated on one side of the base base material, a light-shielding insulating layer is laminated on the other side of the base base material, and metal layers are formed on both sides of the resin film. The conductive sheet has a structure in which a release sheet is further laminated on the conductive adhesive layer side, and has the following shape followability, curl characteristics, and shape retention:
<Shape followability>
The peeling sheet on the conductive adhesive layer side of the test sample cut out from the conductive sheet into a rectangle having a width of 10 mm and a length of 15 mm is removed, and the long side thereof is wrapped around the thick portion of the aluminum plate having a thickness of 1 mm. Moreover, it is attached so as to cover the edge 1 mm of the surface of the aluminum plate, the rest is bent 90 ° and attached to the back surface of the aluminum plate, and when left in an environment of 80 ° C. and 95% RH for 72 hours, no peeling occurs. thing;
<Curl characteristics>
A curl of more than one rotation when the release sheet on the conductive adhesive layer side of the test sample cut out into a strip of 15 mm in width and 150 mm in length is peeled off at a speed of 1000 mm / sec in the 180 ° direction. Does not occur; and <shape retention>
The conductive sheet was cut into strips with a width of 15 mm and a length of 50 mm, and the release sheet on the conductive adhesive layer side of the test sample was peeled off at a speed of 1000 mm / sec in the 180 ° direction, and light-shielding insulation was performed at the center of the sample. Bend 90 ° to the layer side and hold the shape for 10 seconds in that state;
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A conductive sheet in which the linear expansion coefficients of the metal layers formed on both sides of the resin film are 12 to 25 ppm / ° C. The conductivity according to claim 3, wherein the surface of the light-shielding insulating layer of the conductive sheet has a surface resistance value of 1.0 × 10 ⁸ Ω / □ or more, a glossiness of 80% or less, and an optical density of 1 or more. Sheet. The third aspect of claim 3, wherein the surface of the light-shielding insulating layer of the conductive sheet has a surface resistance value of 1.0 × 10 ¹⁰ Ω / □ or more, a glossiness of 40% or less, and an optical density of 1.2 or more. Conductive sheet. The conductive sheet according to any one of claims 3 to 5, wherein the base base material has a structure in which a metal layer is laminated on both sides of a resin film via an adhesive layer. The conductive sheet according to any one of claims 3 to 6, wherein the resin film constituting the base base material has a linear expansion coefficient of 15 to 100 ppm / ° C. The conductive sheet according to claim 7, wherein the difference in linear expansion coefficient between the resin film constituting the base base material and the metal layer is 40 ppm / ° C. or less. The conductivity according to any one of claims 3 to 8, wherein the resin film constituting the base base material has a tensile elastic modulus (JIS K7113) of 0.3 to 15 GPa, and the metal layer has a tensile elastic modulus of 45 to 200 GPa. Sex sheet. The conductive sheet according to claim 9, wherein the difference in tensile elastic modulus (JIS K7113) between the resin film constituting the base base material and the metal layer is 100 GPa or less. The conductivity according to any one of claims 3 to 10, wherein the resin film constituting the base base material, the thickness of the metal layer on the conductive adhesive layer side, and the thickness of the metal layer on the insulating layer side are all 5 to 20 μm. Sex sheet. The ratio of the thickness [Mt1] of the metal layer on the conductive adhesive layer side, the thickness [Bt] of the resin film, and the thickness [Mt2] of the metal layer on the insulating layer side is [Mt1]: [Bt]: [Mt2] = 0. .25-4: 1: 0.25-4. The conductive sheet according to claim 11. The conductive sheet according to any one of claims 3 to 12, wherein the light-shielding insulating layer is a black resin layer formed of an insulating resin colored with a black colorant. The conductive sheet according to claim 13, wherein the black colorant is aniline black. According to any one of claims 3 to 14, the light-shielding insulating layer comprises a black resin layer formed of an insulating resin colored with a black colorant, and an insulating primer layer or a matte varnish layer formed on at least one surface thereof. The conductive sheet described. The conductive sheet according to claim 15, wherein the black colorant is carbon black. An image display module connected by the conductive sheet according to any one of claims 3 to 16, wherein the conductive portion is arranged on an undulating plane. An image display module connected by the conductive sheet according to any one of claims 3 to 16 and having an arrangement in which conductive portions do not exist on the same plane. According to any one of claims 3 to 16, the front surface electrode provided on the front surface outer edge portion of the display surface operation panel and the back surface electrode provided on the back surface outer edge portion are arranged so as to wrap the outer edge portion of the display surface operation panel. An image display module having the display surface operation panel connected by the conductive sheet described and an image display panel operated by the display surface operation panel. An image display module in which the outer edges of at least a part of the members constituting the image display module are attached so as to be wrapped with the conductive sheet according to any one of claims 3 to 16.

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