JP2015030157A - Manufacturing method of transparent conductive laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive laminate having excellent surface smoothness and allowing formation of an accurate electrode pattern on front and back sides in post processing, and a manufacturing method thereof.SOLUTION: A manufacturing method of a transparent conductive laminate 30 includes: a process of bonding a transparent conductive film 10 at least having, on one surface of a transparent base film 1, a hard coat layer 2 and a transparent conductive layer 3 sequentially laminated, and a protective film 20 having an adhesive layer 4 formed on one side of a substrate film 5 at the side of the adhesive layer; and a process of heat-treatment. The difference of maximum heat shrinkage rate to 45 degrees diagonal to a flow direction matching the direction of the transparent conductive film 10 and the protective film 20 when bonded is within 0.2%.

Description

  The present invention relates to a transparent conductive laminate used for flat panel displays such as liquid crystal displays and organic EL displays, and a method for producing the same.

  In display devices such as liquid crystal displays, plasma displays, and organic EL displays, a transparent conductive laminate for a touch panel provided with a hard coat layer and a transparent conductive layer for protecting the surface on a film substrate is used. .

  In these transparent conductive laminates for touch panels, a functional film that provides a function according to the purpose is generally roll-to-roll processed on a transparent plastic film substrate (rolled film raw film). Produced by continuous processing).

  In general, roll-to-roll processing of plastic film base material tends to cause warpage and slip due to winding tension, and sticking and blocking of a smooth coated surface, which adversely affects productivity and quality. It has been known.

  Recently, an optical film laminate has been developed in which two or more types of plastic film base materials are laminated to provide a plurality of higher-level functions.

  In the production of the optical film laminate having higher functions by laminating two or more kinds of plastic film bases as described above, for example, by post-processing such as pattern formation by etching of the transparent conductive layer Further, the warp of the tip becomes a bigger problem, and the flatness of the laminate is required more strictly.

  For these problems, for example, a proposal in Patent Document 1 has been made. Specifically, two film base materials each having a transparent conductive layer are used and laminated such that each of the transparent conductive layers is disposed on the outside, and then electrodes are patterned. Although this proposal is effective for electrode formation, it has no effect on the warp, and a decrease in pattern accuracy due to the warp still remains as an anxiety material.

JP 2009-070191 A

  The present invention provides a transparent conductive laminate that is excellent in flatness and that can accurately form electrode patterns on both sides by post-processing, and a method for producing the same.

As a means for solving the above problems, the invention described in claim 1 includes a transparent conductive film formed by sequentially laminating at least a hard coat layer and a transparent conductive layer on one surface of a transparent substrate film, In the manufacturing method of a transparent conductive laminate comprising a bonding step of bonding the surface of the adhesive layer of the protective film having an adhesive layer formed on one surface of the material film, and a step of heat treatment,
A difference in maximum heat shrinkage with respect to 45 degrees oblique in the flow direction in which directions when the transparent conductive film and the protective film are bonded is within 0.2%. It is a manufacturing method.

  The invention described in claim 2 is the method for producing a transparent conductive laminate according to claim 1, wherein the bonding step is performed by a roll-to-roll method.

  According to invention of Claim 1 which concerns on this invention, the difference of the maximum heat shrinkage | contraction with respect to 45 degree | times slanting of the flow direction in which the direction when a transparent conductive film and a protective film match together through an adhesion layer corresponds. By making the content within 0.2%, thermal shrinkage in the flow direction and the width direction can be suppressed. Further, the occurrence of warpage in the diagonal direction with respect to the flow direction can be reduced by the heat treatment after bonding.

  Moreover, according to Claim 2, the transparent conductive laminated body excellent in flatness can be continuously manufactured efficiently by performing a bonding process by a roll-to-roll system.

It is a schematic diagram which shows the cross section of the transparent conductive laminated body which concerns on this invention. It is a plane schematic diagram which shows the 45-degree direction which concerns on the thermal contraction of a transparent conductive laminated body.

Hereinafter, the present invention will be described in detail with reference to the drawings.
As one embodiment of the present invention, as shown in FIG. 1A, a transparent conductive film 10 formed by sequentially laminating a hard coat layer 2 and a transparent conductive layer 3 on one surface of a transparent substrate film 1; The transparent conductive laminate 30 is formed by laminating the surface of the adhesive layer 4 of the protective film 20 having an adhesive layer formed on one surface of the base film 5, and the transparent conductive film 10 The transparent conductive laminate 30 is characterized in that a difference in maximum heat shrinkage with respect to 45 degrees oblique in the flow direction in which the directions when bonded to the protective film 20 coincide is within 0.2%.

  As one embodiment of the present invention, as shown in FIG. 1 (b), a hard coat layer 2 is provided on both sides of a transparent substrate film 1, and a transparent conductive layer 3 is laminated on one side thereof. A transparent conductive laminate is formed by laminating the hard coat layer 2 on the other surface of the transparent conductive film 10 and the adhesive layer 4 of the protective film 20 having an adhesive layer formed on one surface of the base film 5. A body 30 can also be obtained.

  Furthermore, as one embodiment of the present invention, as shown in FIG. 1 (c), a transparent conductive film obtained by sequentially laminating a hard coat layer 2 and a transparent conductive layer 3 on one surface of a transparent substrate film 1. The transparent conductive laminated body 30 can also be obtained by bonding the 10 transparent conductive layers 3 and the adhesive layer 4 of the protective film 20 having an adhesive layer formed on one surface of the base film 5.

  In any of the forms (a), (b), and (c) shown in FIG. 1, the difference in the maximum heat shrinkage ratio with respect to 45 degrees oblique in the flow direction between the transparent conductive film 10 and the protective film 20 before bonding. If it exceeds 0.2%, warping in an oblique direction, which is considered to be extremely difficult to correct, occurs, and there is a possibility that accuracy and workability in pattern formation of the transparent conductive layer 3 in the subsequent process may be reduced. is there.

FIG. 2 shows a transparent conductive laminate 30 obtained by pasting together the measurement position of the heat shrinkage rate at 45 degrees oblique to the flow direction of the transparent conductive film 10 and the protective film 20 used in the present invention. The position at which the height of the warp is measured is shown. In FIG. 2, D1 indicates a 45 ° oblique left direction, and D2 indicates a 45 ° oblique right direction. Moreover, corner 1, corner 2, corner 3, and corner 4 in FIG. 2 indicate positions of four corners when the obtained transparent conductive laminate 30 is cut into 30 cm square.

In addition, the heat shrinkage rate in the oblique 45 degree direction of the transparent conductive laminate according to the present invention is the distance between two points located at D1 and D2 in FIG. 2 of the transparent conductive laminate at normal temperature before bonding. This is expressed as a percentage (%) of (L ₀ -L ₁ ) / L ₀ when the distance L _{0 is} 150 ° C. and the distance L1 between the two points after storage for 1 hour. The heat shrinkage rate in the vertical direction (flow direction) and the horizontal direction (width direction) was also measured by the same measurement in each direction.

  The transparent base film 1 and the base film 5 used in the present invention have transparency, heat resistance, and mechanical strength within a range that does not hinder the processing steps of the present invention, such as thermoplastic resins and organic-inorganic composite materials. Any film substrate can be used.

  Specific examples include polyethylene, polypropylene, polyester, polyvinyl chloride, cellophane, polyamide, polyvinyl alcohol, polycarbonate, polyacetate, akyryl, polystyrene, fluororesin, and triacetyl cellulose.

  Further, the hard coat layer 2 is required to be excellent in transparency, mechanical properties, heat resistance, chemical resistance, etc. as well as hardness, and specifically, a polyfunctional acrylate capable of cross-linking is mainly used. It is desirable to form from an ionizing radiation curable resin formed by crosslinking monomers and oligomers as components.

  As the polyfunctional acrylate, for example, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, polyester acrylate and the like are preferable. These may be used alone or in combination of two or more. In addition to these acrylates, acrylate resins such as epoxy acrylate and urethane acrylate may be used in combination.

  When the ionizing radiation is ultraviolet light, a photopolymerization initiator is required. For example, benzoin, its alkyl ethers, acetophenones, benzophenones, etc. can be used.

  The composition comprising the ionizing radiation curable resin can contain various additives and solvents in order to impart storage stability and coating suitability of the coating liquid.

  Examples of the transparent conductive layer 3 according to the present invention include materials such as indium-tin composite oxide (ITO), tin oxide, copper, aluminum, nickel, and chromium. But you can. Moreover, as a method of forming a transparent conductive layer using these materials, sputtering method, vacuum deposition method, PVD method of ion plating method, CVD method, coating method, printing method and the like can be used.

  Examples of the pressure-sensitive adhesive layer according to the present invention include, but are not limited to, an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, and a silicone-based pressure-sensitive adhesive. The thickness is preferably 10 μm to 200 μm. If the thickness is less than 10 μm, sufficient adhesion cannot be ensured, and unevenness in color becomes conspicuous due to slight thickness unevenness. On the other hand, when the thickness exceeds 200 μm, the transparency is inferior and the appearance is inferior. In addition, the total thickness of the transparent conductive laminate is increased, the cost is high, and the productivity is inferior.

Thus, by heat-treating the transparent conductive film 10 on which the protective film 20 is bonded, the transparent conductive layer 3 can be crystallized without causing warpage. And the transparent conductive laminated body for touch panels can be manufactured by etching the crystallized transparent conductive layer 3.

  Hereinafter, the present invention will be specifically described by way of examples. In addition, as an Example, it implemented with the form shown in FIG.1 (b).

(Preparation of transparent conductive film)
A composition for forming a hard coat layer (DIC: Unidic V-9500) containing an ultraviolet curable acrylic resin on both sides of a polyethylene terephthalate (PET) film having a thickness of 125 μm and a film thickness after UV curing of 3 μm. Then, it was cured by irradiating with ultraviolet rays to form a hard coat layer. At this time, the processing was performed under two conditions by changing the winding tension / speed and the drying temperature.

  Next, a transparent conductive layer having a thickness of 30 nm was formed by sputtering ITO on one surface of the hard coat layer processed under the above two conditions to produce two types of transparent conductive films A1 and A2.

(Preparation of protective film)
Two types of protective films are applied to one surface of biaxially stretched PET with a thickness of 50 μm by applying an acrylic adhesive so that the film thickness after drying is 25 μm, and adjusting the winding tension / speed and drying temperature. B1 and B2 were produced.

  The thermal contraction rate of each of the transparent conductive films A1 and A2 and the protective films B1 and B2 prepared above in the vertical direction, the horizontal direction, and the 45 ° diagonal direction (D1, D2) was measured. The measurement results are shown in Table 1 below.

<Example 1>
Difference in maximum heat shrinkage ratio with respect to 45 degrees oblique in the flow direction in which the direction when the transparent conductive layer of the transparent conductive film A1 is not laminated and the surface of the adhesive layer of the protective film B1 coincide with each other. So as to be within 0.2%, pressure was applied by a roll-to-roll method, followed by heat treatment to produce a transparent conductive laminate.

<Example 2>
A transparent conductive laminate was produced in the same manner as in Example 1 except that the transparent conductive film A2 and the protective film B2 were bonded together.

<Comparative Example 1>
A transparent conductive laminate was produced in the same manner as in Example 1 except that the transparent conductive film A1 and the protective film B2 were bonded together.

<Comparative example 2>
A transparent conductive laminate was produced in the same manner as in Example 1 except that the transparent conductive film A2 and the protective film B1 were bonded together.

<Evaluation>
The transparent conductive laminates obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were each cut into 30 cm squares, then allowed to stand at 150 ° C. for 1 hour, and then cooled at room temperature for 1 hour. The height of the warp was measured at positions of 1, 2, 2, and 4. In addition, in the case of a corner having a curvature that is convex upward, the corner was turned over, the height from the plane was measured, and the value was displayed as minus. The results are shown in Table 2 below.

<Comparison result>
The combination of the transparent conductive film A1 and the protective film B1 used in Example 1 has a maximum heat shrinkage difference of 0.17% in an oblique 45 degree direction in which the directions when bonded are the same. The warp of 2 to 5 mm was a good result. In addition, the combination of the transparent conductive film A2 and the protective film B2 used in Example 2 has a difference in maximum heat shrinkage in the oblique 45 degree direction of 0.05%, and the warpage at the four corners is -1 to -1. A very good result of 3 mm was obtained.

  On the other hand, the combination of the transparent conductive film A1 and the protective film B2 used in Comparative Example 1 is 0.22% in the difference in the maximum heat shrinkage in the oblique 45 ° direction in which the directions when bonded are the same, The warping of the four corners of the transparent conductive laminate obtained by bonding showed a large value of −1 to 15 mm. In addition, the combination of the transparent conductive film A2 and the protective film B1 used in Comparative Example 2 has a maximum heat shrinkage difference of 0.20% in the oblique 45 degree direction, and the transparent conductive film obtained by bonding. The warp at the four corners of the conductive laminate showed a large value of -4 to 10 mm, and a warp having a practical problem occurred.

  The present invention can provide a transparent conductive laminate excellent in flatness, for example, easy post-processing according to requirements such as patterning of a transparent conductive layer, and a transparent electrode for various display touch panels and solar cells. Can be used.

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate film 2 ... Hard coat layer 3 ... Transparent conductive layer 4 ... Adhesive layer 5 ... Base film 10 ... Transparent conductive film 20 ..Protective film 30 ... transparent conductive laminate D1 ... diagonal left 45 degrees direction D2 ... diagonal right 45 degrees direction

Claims (2)

A transparent conductive film formed by sequentially laminating at least a hard coat layer and a transparent conductive layer on one surface of the transparent substrate film; and the adhesive layer of the protective film having an adhesive layer formed on one surface of the substrate film. In the method for producing a transparent conductive laminate comprising a laminating step of laminating the surfaces and a step of heat treatment,
A difference in maximum heat shrinkage with respect to 45 degrees oblique in the flow direction in which directions when the transparent conductive film and the protective film are bonded is within 0.2%. Production method.   The method for producing a transparent conductive laminate according to claim 1, wherein the bonding step is performed by a roll-to-roll method.

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