# US 2018/0022962 A1 · Electroconductive film laminate comprising transparent pressure-sensitive adhesive layer

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- Number: US 2018/0022962 A1
- Document ID: US20180022962A1
- Status: Published application
- Kind: A1
- Application number: 15/545,124
- Filed: 2016-07-11
- Published: 2018-01-25
- Earliest claimed: 2015-07-22
- Assignees: Nitto Denko Corporation
- Applicants: Nitto Denko Corporation
- Inventors: Hirofumi KATAMI; Toru UMEMOTO; Hiroyuki TAKAO; Atsushi YASUI
- Web page: https://patentgrep.com/patent/US20180022962A1

## CPC

- C09J 7/385: {Acrylic polymers}
- B32B 7/12: using interposed adhesives or interposed materials with bonding properties
- B32B 17/00: Layered products essentially comprising sheet glass, or glass, slag, or like fibres
- B32B 23/08: of synthetic resin
- B32B 23/20: comprising esters
- B32B 25/08: of synthetic resin
- B32B 27/06: as the main or only constituent of a layer, {which is} next to another layer of {the same or of} a {different material (next to a layer of a particular substance B32B9/045; next to a bituminous or tarry layer B32B11/046; next to a water setting substance layer B32B13/12; next to a metal layer B32B15/08; next to a glass layer B32B17/10; next to a layer formed of natural mineral fibres or particles B32B19/045; next to a wood layer B32B21/08; next to a cellulosic plastic layer B32B23/08; next to a natural or synthetic rubber layer B32B25/08)}
- B32B 27/08: of synthetic resin
- B32B 27/16: specially treated, e.g. irradiated
- B32B 27/18: characterised by the use of special additives
- B32B 27/20: using fillers, pigments, thixotroping agents
- B32B 27/22: using plasticisers
- B32B 27/285: {comprising polyethers}
- B32B 27/308: {comprising acrylic (co)polymers}
- B32B 27/32: comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)}
- B32B 27/325: {comprising polycycloolefins}
- B32B 27/36: comprising polyesters
- B32B 27/38: comprising epoxy resins
- B32B 27/40: comprising polyurethanes
- C09J 7/24: based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
- C09J 201/00: Adhesives based on unspecified macromolecular compounds
- B05D 1/28: performed by transfer from the surfaces of elements carrying the liquid or other fluent material, e.g. brushes, pads, rollers
- B32B 2255/10: on synthetic resin layer or on natural or synthetic rubber layer
- B32B 2255/20: Inorganic coating
- B32B 2255/26: Polymeric coating
- B32B 2255/28: Multiple coating on one surface
- B32B 2264/10: Inorganic particles
- B32B 2264/102: Oxide or hydroxide
- B32B 2307/202: Conductive
- B32B 2307/21: Anti-static
- B32B 2307/306: Resistant to heat
- B32B 2307/40: having particular optical properties
- B32B 2307/4026: within the layer by addition of a colorant, e.g. pigments, dyes
- B32B 2307/412: Transparent
- B32B 2307/418: Refractive
- B32B 2307/42: Polarizing, birefringent, filtering
- B32B 2307/708: Isotropic
- B32B 2307/712: Weather resistant
- B32B 2307/714: Inert, i.e. inert to chemical degradation, corrosion
- B32B 2307/732: Dimensional properties
- B32B 2307/734: Dimensional stability
- B32B 2307/746: Slipping, anti-blocking, low friction
- B32B 2307/752: Corrosion inhibitor
- B32B 2457/202: LCD, i.e. liquid crystal displays
- B32B 2457/206: Organic displays, e.g. OLED
- B32B 2457/208: Touch screens
- C08K 2003/2206: {of calcium, strontium or barium}
- C08K 2003/2213: {of cerium}
- C08K 2003/2227: {of aluminium}
- C08K 2003/2231: {of tin}
- C08K 2003/2237: {of titanium}
- C08K 2003/2244: {of zirconium}
- C08K 2003/2258: {of tungsten}
- C09J 2203/318: for the production of liquid crystal displays
- C09J 2301/124: the adhesive layer being present on both sides of the carrier, e.g. double-sided adhesive tape
- C09J 2301/208: the adhesive layer being constituted by at least two or more adjacent or superposed adhesive layers, e.g. multilayer adhesive
- C09J 2301/302: the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C
- C09J 2301/314: the adhesive layer and/or the carrier being conductive
- C09J 2301/408: additives as essential feature of the adhesive layer
- C09J 2423/006: in the substrate
- C23C 14/086: {of zinc, germanium, cadmium, indium, tin, thallium or bismuth}
- C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)

## Abstract

As one sensor layer structure for a capacitive touch panel, a layer structure in which a transparent electroconductive layer is formed on each of opposite surfaces of a single film substrate, so-called GFD structure, is used. In the structure, for sufficiently suppressing internal reflection from the transparent electroconductive layer, it is necessary to employ a technique of forming one or more refractive index adjustment (IM) layers on each of the opposite surfaces of the single film substrate. This causes a problem that production yield is likely to deteriorate, and a production cost is increased. The present invention is directed to solving such a problem and, specifically, to laminating a refractive index adjustment zone-formed pressure-sensitive adhesive layer capable of being produced easily and at low cost, to each transparent electroconductive layer of a double-sided transparent electroconductive film, so as to effectively suppress internal reflection in the resulting laminate.

## Claims

### Claim 1

A double-sided transparent electroconductive film laminate comprising:
a transparent film substrate;
a first transparent electroconductive layer on one of opposite surfaces of the transparent film substrate;
a second transparent electroconductive layer on the other surface of the transparent film substrate;
a transparent, first pressure-sensitive adhesive layer on a surface of the first transparent electroconductive layer on a side opposite to the transparent film substrate; and
a transparent, second pressure-sensitive adhesive layer on a surface of the second transparent electroconductive layer on a side opposite to the transparent film substrate,
wherein each of the first and second pressure-sensitive adhesive layers comprises:
a base adhesive zone made essentially of a transparent base pressure-sensitive adhesive material and formed over a given range from one principal surface of the pressure-sensitive adhesive layer in a thickness direction of the pressure-sensitive adhesive layer; and
a transparent, adherent, refractive index adjustment zone formed over a given range from the other principal surface of the pressure-sensitive adhesive layer in the thickness direction, the refractive index adjustment zone being in contact with a corresponding one of the first and second transparent electroconductive layers, and having a refractive index greater than a refractive index of the base pressure-sensitive adhesive material.

### Claim 2 (depends on 1)

The double-sided transparent electroconductive film laminate as recited in claim 1, wherein each of the first and second transparent electroconductive layers is patterned.

### Claim 3 (depends on 1)

The double-sided transparent electroconductive film laminate as recited in claim 1, wherein the first transparent electroconductive layer is patterned, and the second transparent electroconductive layer is not patterned.

### Claim 4 (depends on 2)

The double-sided transparent electroconductive film laminate as recited in claim 2, which further comprises:
a cover element on a surface of the first pressure-sensitive adhesive layer on a side opposite to the first transparent electroconductive layer; and
an image display device or a protective film on a surface of the second pressure-sensitive adhesive layer on a side opposite to the second transparent electroconductive layer.

### Claim 5 (depends on 1)

The double-sided transparent electroconductive film laminate as recited in claim 1, wherein the transparent film substrate has a thickness of 2 μm to 200 μm.

### Claim 6 (depends on 1)

The double-sided transparent electroconductive film laminate as recited in claim 1, wherein the refractive index adjustment zone has a thickness of 20 nm to 600 nm.

### Claim 7 (depends on 1)

The double-sided transparent electroconductive film laminate as recited in claim 1, wherein the refractive index adjustment zone is formed by dispersing, in a pressure-sensitive adhesive material identical to the base pressure-sensitive adhesive material, particles of a high refractive index material having a refractive index greater than that of the pressure-sensitive adhesive material, to thereby increase an average refractive index of the refractive index adjustment zone.

### Claim 8 (depends on 7)

The double-sided transparent electroconductive film laminate as recited in claim 7, wherein the refractive index of the high refractive index material particles is in the range of 1.60 to 2.74.

### Claim 9 (depends on 7)

The double-sided transparent electroconductive film laminate as recited in claim 7, wherein the high refractive index material particles have an average primary particle size of 3 nm to 100 nm as measured by TEM observation.

### Claim 10 (depends on 7)

The double-sided transparent electroconductive film laminate as recited in claim 7, wherein a difference between the refractive index of the high refractive index material particles and the refractive index of the base pressure-sensitive adhesive material is in the range of 0.15 to 1.34.

### Claim 11 (depends on 7)

The double-sided transparent electroconductive film laminate as recited in claim 7, wherein the high refractive index material is one or more compounds selected from the group consisting of TiO2, ZrO2, CeO2, Al2O3, BaTiO3, Nb2O5 and SnO2.

### Claim 12 (depends on 1)

The double-sided transparent electroconductive film laminate as recited in claim 1, wherein the refractive index adjustment zone is formed by adding, to a pressure-sensitive adhesive material identical to the base pressure-sensitive adhesive material, an organic material having a refractive index greater than that of the pressure-sensitive adhesive material, in the form of particle, polymer or oligomer, to thereby increase an average refractive index of the refractive index adjustment zone.

### Claim 13 (depends on 12)

The double-sided transparent electroconductive film laminate as recited in claim 12, wherein the refractive index of the base pressure-sensitive adhesive material is in the range of 1.40 to 1.55, and the refractive index of the organic material is in the range of 1.59 to 2.04.

### Claim 14 (depends on 1)

The double-sided transparent electroconductive film laminate as recited in claim 1, wherein each of the first and second pressure-sensitive adhesive layers has a total light transmittance of 80% or more.

### Claim 15 (depends on 7)

The double-sided transparent electroconductive film laminate as recited in claim 7, wherein the high refractive index material particles partially exist in the form of an aggregate arising from aggregation of two or more thereof.

### Claim 16 (depends on 1)

The double-sided transparent electroconductive film laminate as recited in claim 1, wherein the refractive index adjustment zone exists with irregular depths in the thickness direction of the pressure-sensitive adhesive layer.

### Claim 17 (depends on 1)

The double-sided transparent electroconductive film laminate as recited in claim 1, wherein the transparent film substrate comprises: a first refractive index adjustment layer with respect to the first transparent electroconductive layer; and a second refractive index adjustment layer with respect to the second transparent electroconductive layer.

### Claim 18 (depends on 1)

The double-sided transparent electroconductive film laminate as recited in claim 1, wherein a refractive index n1 of each of the first and second transparent electroconductive layers, the refractive index n2 of the refractive index adjustment zone and the refractive index n3 of the transparent base pressure-sensitive adhesive material satisfy the following relationship: n1>n2>n3.