TWI807140B - Transparent conductive film laminate - Google Patents

Abstract

The object of the present invention is to provide a transparent conductive film laminate in which curling and outgassing are suppressed. The solution is to use a base film having a small dimensional shrinkage in both the first direction and the second direction perpendicular to the first direction and having an MIT number of 500 or more.

Description

Transparent conductive thin film laminate

The present invention relates to a transparent conductive thin film laminate.

Transparent conductive films used in touch panels, etc., are temporarily bonded to a carrier film to form a laminate during actual use, and the laminate is used for manufacturing, transportation, storage, etc. However, in the case of conventional transparent conductive thin film laminates, curling may occur in the heating step, resulting in insufficient production efficiency.

Prior Art Documents patent documents Patent Document 1: Japanese Patent Laid-Open No. 2017-190406

The problem to be solved by the invention

This invention was made in order to solve the said conventional problem, It aims at providing the transparent electroconductive thin film laminated body in which the generation|occurrence|production of curling and outgassing (outgas) was suppressed. means for solving problems

The transparent conductive film laminate in the embodiment of the present invention includes: a conductive film comprising a resin film and a conductive film; and a carrier film having a base film comprising a polyester resin and an adhesive layer disposed on one side of the base film, and temporarily adhered to the conductive film in a peelable state through the adhesive layer; the carrier film is laminated on the opposite side of the conductive film; the base film has a glass transition temperature (Tg) of 150° C. Each of the first direction and the second direction perpendicular to the first direction is 0.2% or less, and the number of MITs is 500 or more. In one embodiment, the polyester-based resin includes a polymer of (A) acid component and (B) alcohol component. The (A) component includes (A1) a monocyclic aromatic polycarboxylic acid component, (A2) a polycyclic aromatic polycarboxylic acid component and (A3) a fluorene-based polycarboxylic acid component. The (B) component includes (B1) an aliphatic polyol component and (B2) a fluorene-based polyol component; 30 mol%, the content rate of the (A3) component is 5 mol% or more and 50 mol% or less; the (B2) component does not contain a substantial amount of 9,9-bis(aryl-hydroxy(poly)alkoxyaryl)fluorene component. In one embodiment, the above-mentioned (B2) component includes the first fluorene component in which two substituents having a hydroxyl group are introduced into the 9-position. In one embodiment, the above-mentioned (B1) component contains a 1,2-propanediol component, and the above-mentioned (B2) component contains a 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene component. In one embodiment, the above-mentioned (A3) component includes a second fluorene component in which two substituents having a carboxyl group and/or an ester group are introduced into the 9-position. In one embodiment, the above-mentioned (A1) component contains a terephthalic acid component, the above-mentioned (A2) component contains a 2,6-naphthalene dicarboxylic acid component, and the above-mentioned (A3) component contains a 9,9-bis(carboxyethyl)fluorene component. In one embodiment, the above-mentioned carrier film has a thickness of 15 μm to 100 μm. Invention effect

According to an embodiment of the present invention, in a transparent conductive film laminate having a transparent conductive film and a carrier film, by using a base film that contains a predetermined polyester resin, has a small dimensional shrinkage in both the first direction and the second direction perpendicular to the first direction, and has an MIT number of 500 or more, a transparent conductive film laminate in which curling and outgassing are suppressed can be obtained.

Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

A. Transparent conductive film laminate Fig. 1 is a schematic cross-sectional view of a transparent conductive thin film laminate according to an embodiment of the present invention. A transparent conductive film laminate 100 of the illustrated example has a transparent conductive film 10 and a carrier film 20 . The transparent conductive film 10 represents a resin film 14 and a conductive layer 11 thereon. The carrier film 20 represents a base film 22 and an adhesive layer 21 , and is temporarily bonded to the transparent conductive film 10 in a peelable state through the adhesive layer 21 . The carrier film can optionally also have an anti-adhesion hardcoat (ABHC) layer 23 .

In the embodiment of the present invention, the glass transition temperature (Tg) of the base film 22 is above 150°C, preferably above 155°C. In addition, the dimensional shrinkage of the base film 22 at 145° C. is 0.2% or less in each of the first direction and the second direction perpendicular to the first direction. The first direction corresponds to, for example, the MD direction in a manufacturing method described later, and the second direction corresponds to, for example, the TD direction. In addition, the number of MITs of the base film 22 is 500 or more. As long as the glass transition temperature (Tg), dimensional shrinkage at 145°, and MIT number of the base film 22 are within the above ranges, a transparent conductive film laminate in which curling and outgassing are suppressed can be obtained. In addition, the number of times of folding resistance of the base film 22 is preferably 100 or more.

The thickness of the carrier film 20 is preferably 15 μm-100 μm, more preferably 15 μm-80 μm, and more preferably 15 μm-60 μm. As long as the thickness of the carrier film is within the above-mentioned range, a transparent conductive film laminate in which curling and outgassing are suppressed can be obtained. In addition, the thickness of the carrier film refers to the total thickness when the base film, the adhesive layer and, if necessary, the anti-adhesion hard coat (ABHC) are laminated.

B. Transparent conductive film The transparent conductive film 10 according to the embodiment of the present invention includes a resin film 14 and a conductive layer 11 . The conductive layer is typically formed on the viewing-side surface of the resin film. The transparent conductive film may also have an index matching (IM) layer 12 , a hard coat (HC) layer 13 and/or an anti-adhesion hard coat (ABHC) layer 15 as needed.

(resin film) The resin film may be composed of any appropriate resin. Examples of the resin constituting the resin film include cycloolefin-based resins (COP) and polyester-based resins. The details of the cycloolefin-based resin (COP) are described in, for example, JP-A-2016-107503. The description of this publication is incorporated by reference in this specification.

The thickness of the resin film is preferably 10 μm-80 μm, more preferably 10 μm-60 μm, and more preferably 10 μm-40 μm.

(conductive layer) The conductive layer represents a transparent conductive layer. The total light transmittance of the conductive layer is preferably above 80%, more preferably above 85%, and more preferably above 90%.

The density of the conductive layer is preferably 1.0g/cm ³ ~10.5g/cm ³ , more preferably 1.3g/cm ³ ~8.0g/cm ³ .

The surface resistance of the conductive layer is preferably 0.1Ω/□~1000Ω/□, more preferably 0.5Ω/□~500Ω/□, and more preferably 1Ω/□~250Ω/□.

A representative example of the conductive layer includes a conductive layer made of a metal oxide. Examples of metal oxides include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Among them, indium-tin composite oxide (ITO) is preferable.

The thickness of the conductive layer is preferably 0.01 μm to 0.06 μm, more preferably 0.01 μm to 0.045 μm. If it is the said range, the electroconductive layer excellent in electroconductivity and translucency can be obtained.

The conductive layer can typically be formed by sputtering on the surface of the resin film.

(Index matching (IM) layer) The IM layer may be formed on one side of the conductive layer. As for the IM layer, a well-known configuration in the industry can be employed, so detailed description is omitted.

(Hard Coat (HC) Layer) The HC layer may be formed between the above-mentioned IM layer and the resin film. As for the HC layer, a well-known configuration in the industry can be employed, and thus detailed description thereof will be omitted.

(Anti-Adhesion Hardcoat (ABHC) layer) The ABHC layer may be formed on the surface of the resin film opposite to the HC layer. The details of the ABHC layer are described in, for example, JP-A-2016-107503. The description of this publication is incorporated by reference in this specification.

C. Carrier film The carrier film 20 includes an adhesive layer 21 and a base film 22 . The carrier film 20 can optionally have an anti-adhesion hardcoat (ABHC) layer 23 .

(base film) The base film according to the embodiment of the present invention is composed of a film made of a polyester resin. The polyester-based resin represents a polymer including (A) an acid component and (B) an alcohol component. (A) component contains (A1) monocyclic aromatic polyhydric carboxylic acid component, (A2) polycyclic aromatic polyhydric carboxylic acid component, and (A3) fluorene type polyhydric carboxylic acid component. (B) A component contains (B1) an aliphatic polyol component, and (B2) a fluorene type polyol component. Typically, the content of component (A1) is 5 mol% to less than 30 mol%, and the content of component (A3) is 5 mol% to 50 mol% based on the total amount of component (A). The (B2) component represents substantially no 9,9-bis(aryl-hydroxy(poly)alkoxyaryl)fluorene component.

The monocyclic aromatic polyhydric carboxylic acid component (A1) may contain a component having a plurality of carboxyl group-containing substituents introduced into the benzene ring. As (A1) component, a terephthalic-acid component and an isophthalic-acid component are mentioned, for example. Among the components (A1), terephthalic acid is preferably at least 50 mol%, more preferably at least 70 mol%, preferably at least 80 mol%, more preferably at least 90 mol%, and more preferably 100 mol%. Heat resistance can be improved by mainly using terephthalic acid.

A polycyclic aromatic polyhydric carboxylic acid component (A2) may contain a component having a plurality of substituents having a carboxyl group introduced into the naphthalene ring. In this specification, (A3) component is not included in (A2) component. Examples of the component (A2) include 2,6-naphthalene dicarboxylic acid components, 1,5-naphthalene dicarboxylic acid components, 1,6-naphthalene dicarboxylic acid components, 1,7-naphthalene dicarboxylic acid components, and 1,8-naphthalene dicarboxylic acid components. Among the components (A2), the 2,6-naphthalene dicarboxylic acid component is preferably at least 50 mol%, preferably at least 70 mol%, more preferably at least 80 mol%, more preferably at least 90 mol%, and more preferably 100 mol%. Heat resistance can be improved by using 2,6-naphthalene dicarboxylic acid as the main component.

The fluorene-based polyvalent carboxylic acid component (A3) may contain a component in which a plurality of substituents having a carboxyl group are introduced into fluorene. An example of the chemical formula of the fluorene-based polyvalent carboxylic acid component is shown in Chemical Formula 1 below. (A3) The component which introduced two substituents which have a carboxyl group and/or ester group to the 9-position of fluorene, for example can be contained. In Chemical Formula 1, R ¹ and R ² may use the same substituent. R ¹ and R ² can be, for example, carboxyalkyl (-(CH ₂ ) _n COOH). As (A3) component, the 9,9- bis (carboxyethyl) fluorene component etc. which are represented by following chemical formula 2 are mentioned, for example. Among the components (A3), the 9,9-bis(carboxyethyl)fluorene component is preferably at least 50 mol%, preferably at least 70 mol%, more preferably at least 80 mol%, preferably at least 90 mol%, more preferably 100 mol%. By using 9,9-bis(carboxyethyl)fluorene as the main component, birefringence can be reduced, and as a result, a base film having a desired in-plane retardation can be obtained.

[chemical formula 1] [chemical formula 2]

The content of the component (A1) is preferably 5 mol% or more, preferably 8 mol% or more, more preferably 10 mol% or more, based on the total amount of the acid component. When the content rate of (A1) component is less than 5 mol%, birefringence may become large. The content of the component (A1) is preferably less than 30 mol %, more preferably 29 mol % or less, more preferably 28 mol % or less, based on the total amount of the acid component. Heat resistance may become insufficient as the content rate of (A1) component is 30 mol% or more.

The content of the component (A2) is preferably 25 mol% or more, preferably 30 mol% or more, more preferably 35 mol% or more, based on the total amount of the acid component. When the content rate of (A2) component is less than 25 mol%, heat resistance may become insufficient. The content of the component (A2) is preferably not more than 70 mol %, more preferably not more than 60 mol %, more preferably not more than 55 mol %, based on the total amount of the acid component. When the content rate of (A2) component exceeds 70 mol%, birefringence may become large.

The content of the component (A3) is preferably 5 mol% or more, preferably 10 mol% or more, more preferably 15 mol% or more, based on the total amount of the acid component. When the content rate of (A3) component is less than 5 mol%, birefringence may become large. The content of the component (A3) is preferably not more than 50 mol %, more preferably not more than 45 mol %, more preferably not more than 40 mol %, based on the total amount of the acid component. When the content rate of (A3) component exceeds 50 mol%, heat resistance may become inadequate.

The molar ratio (A1)/(A2) of the component (A1) and the component (A2) is preferably 0.1 to 0.9, more preferably 0.2 to 0.8, more preferably 0.3 to 0.75. The molar ratio (A1)/(A3) of the component (A1) and the component (A3) is preferably 0.4 to 3, preferably 0.5 to 2.7, more preferably 0.6 to 2.5. The molar ratio (A2)/(A3) of the component (A2) and the component (A3) is preferably 0.8 to 3, preferably 1 to 2.7, more preferably 1.2 to 2.5.

The aliphatic polyol component (B1) may contain an alkanediol component having 2 to 4 carbon atoms. Examples of the component (B1) include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, and 1,4-butanediol. Among the components (B1), the 1,2-propanediol component is preferably at least 50 mol%, preferably at least 70 mol%, preferably at least 80 mol%, more preferably at least 90 mol%, and more preferably 100 mol%. By using 1,2-propanediol as the main component, the glass transition temperature can be increased compared with other aliphatic polyols.

The fluorene-based polyol component may contain a component in which a plurality of substituents having a hydroxyl group are introduced into fluorene. An example of the chemical formula of the fluorene-based polyol component is shown in Chemical Formula 3 below. (B2) The component which introduced the substituent which has two hydroxyl groups to the 9-position of fluorene, for example can be contained. In Chemical Formula 3, R ³ and R ⁴ may use the same substituent. R ³ and R ⁴ can be, for example, a hydroxyalkoxyaryl group. Examples of the component (B2) include 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene component, 9,9-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene component, 9,9-bis[4-(2-hydroxyethoxy)-3,5-dimethylphenyl]fluorene component, 9,9-bis[4-(2-hydroxyethoxy)-3,5-diethylphenyl]fluorene component, and the like. Among them, the component (B2) is particularly preferably a 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene component represented by Chemical Formula 4 below. Among the components (B2), the 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene component is preferably at least 50 mol%, preferably at least 70 mol%, more preferably at least 80 mol%, preferably at least 90 mol%, and more preferably 100 mol%. By using 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene as the main component, the heat resistance of the base film obtained can be improved, and birefringence (resulting in-plane retardation) can be reduced. Especially among the components (B2), the 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene component is more preferably 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more, more preferably 100 mol%.

The component (B2) preferably does not contain a substantial amount of the 9,9-bis(aryl-hydroxy(poly)alkoxyaryl)fluorene component. Examples of the 9,9-bis(aryl-hydroxy(poly)alkoxyaryl)fluorene component include a 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene component represented by Chemical Formula 5 below. When a 9,9-bis(aryl-hydroxy(poly)alkoxyaryl)fluorene component is contained, mechanical properties and/or moldability may become insufficient. Here, the "substantial amount" refers to an amount capable of producing the effect of the 9,9-bis(aryl-hydroxy(poly)alkoxyaryl)fluorene component.

[chemical formula 3] [chemical formula 4] [chemical formula 5]

The content of the component (B1) is preferably 3 mol% or more, preferably 5 mol% or more, more preferably 8 mol% or more, based on the total amount of the alcohol component. When the content rate of (B1) component is less than 3 mol%, mechanical characteristics and/or formability may become inadequate. The content of the component (B1) is preferably 30 mol% or less, preferably 20 mol% or less, more preferably 15 mol% or less, based on the total amount of the alcohol component. When the content rate of (B1) component exceeds 30 mol%, heat resistance may become inadequate.

The content of the component (B2) is preferably 70 mol% or more, preferably 80 mol% or more, more preferably 85 mol% or more, based on the total amount of the alcohol component. When the content rate of (B2) component is less than 70 mol%, heat resistance may become insufficient. The content of the component (B2) is preferably not more than 97 mol %, more preferably not more than 95 mol %, more preferably not more than 92 mol %, based on the total amount of the alcohol component. When the content rate of (B2) component exceeds 97 mol%, mechanical characteristics and/or formability may become inadequate.

The molar ratio (B2)/(B1) of the component (B1) to the component (B2) is preferably 4-30, more preferably 6-20, more preferably 7-10.

Details of the polyester-based resin are described in, for example, JP-A-2018-168210. The description of this publication is incorporated by reference in this specification.

The thickness of the base film is preferably 10 μm-80 μm, more preferably 10 μm-60 μm, and more preferably 10 μm-40 μm.

The elastic modulus of the base film should be 50MPa~350MPa at a stretching speed of 100mm/min. As long as the modulus of elasticity is within the above range, a base film excellent in conveyability and handleability can be obtained. According to the embodiment of the present invention, excellent elastic modulus (strength) and excellent flexibility or bending resistance (softness) as above can be achieved at the same time. In addition, elastic modulus is measured based on JISK7127:1999.

The tensile elongation of the base film should be 70%~200%. As long as the tensile elongation is within the above-mentioned range, there is an advantage that it is difficult to break during transportation. In addition, tensile elongation is measured based on JISK6781.

(Manufacturing method of base film) The method for producing a base film according to an embodiment of the present invention includes: forming a film-forming material (resin composition) containing the polyester-based resin described in item A above into a film; and stretching the formed film.

The film-forming material may contain other resins as described above in addition to the above-mentioned polyester-based resin, may contain additives, and may contain a solvent. As the additive, any appropriate additive can be employed according to the purpose. Specific examples of additives include reactive diluents, plasticizers, surfactants, fillers, antioxidants, antiaging agents, ultraviolet absorbers, leveling agents, thixotropic agents, antistatic agents, conductive materials, and flame retardants. The number, type, combination, addition amount, etc. of the additives can be appropriately set according to the purpose.

As a method of forming a thin film from a thin film forming material, any appropriate forming method can be adopted. Specific examples include compression molding, transfer molding, injection molding, extrusion molding, blow molding, powder molding, FRP molding, casting coating (such as casting), calendering, and hot pressing. It is preferably extrusion molding or casting coating. This is because the smoothness of the obtained film can be improved and good optical uniformity can be obtained. The molding conditions can be appropriately set according to the composition and type of the resin used, desired properties of the base film, and the like.

The film stretching method is typically biaxial stretching, and more specifically, sequential biaxial stretching or simultaneous biaxial stretching. This is because a base film having a small in-plane retardation can be obtained. Sequential biaxial stretching or simultaneous biaxial stretching is typically performed using a tenter stretching machine. Therefore, the stretching direction of the film typically refers to the longitudinal direction and the width direction of the film.

The stretching temperature varies depending on the desired in-plane retardation and thickness of the base film, the type of resin to be used, the thickness of the film to be used, the stretching ratio, and the like. Specifically, the stretching temperature relative to the glass transition temperature (Tg) of the film is preferably Tg+5°C~Tg+50°C, more preferably Tg+10°C~Tg+40°C. By performing stretching at such a temperature, a base film having appropriate characteristics can be obtained in the embodiment of the present invention.

The stretching ratio varies depending on the desired in-plane retardation and thickness of the base film, the type of resin to be used, the thickness of the film to be used, the stretching temperature, and the like. When using biaxial stretching (for example, sequential biaxial stretching or simultaneous biaxial stretching), the difference between the stretching ratio in the first direction (such as the length direction) and the stretching ratio in the second direction (such as the width direction) should be as small as possible, and more preferably substantially equal. With such a configuration, a resin film having a small in-plane retardation can be obtained. When using biaxial stretching (for example, sequential biaxial stretching or simultaneous biaxial stretching), the stretching ratio can be, for example, 1.1 times to 3.0 times in the first direction (such as the longitudinal direction) and the second direction (such as the width direction), respectively.

In the embodiment of the present invention, the stretching speed is preferably below 10%/sec, more preferably below 7%/sec, more preferably below 5%/sec, especially preferably below 2.5%/sec. A base film having a small in-plane retardation can be obtained by stretching a film containing the above-mentioned specific polyester-based resin at the above-mentioned low stretching speed. The lower limit of the stretching speed may be, for example, 1.2%/sec. If the stretching speed is too low, the productivity may become impractical. In addition, in the case of biaxial stretching (for example, sequential biaxial stretching or simultaneous biaxial stretching), the difference between the stretching speed in the first direction (such as the longitudinal direction) and the stretching speed in the second direction (such as the width direction) should be as small as possible, more preferably substantially equal. With such a configuration, the in-plane retardation Re(550) of the base film can be reduced.

(adhesive layer) As the pressure-sensitive adhesive layer, as long as it has transparency, it can be used without particular limitation. Specifically, for example, acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate/vinyl chloride copolymers, modified polyolefins, epoxy-based, fluorine-based, natural rubber, synthetic rubber and other rubber-based polymers can be appropriately selected and used. In particular, an acrylic adhesive is preferably used from the viewpoint of excellent optical transparency, moderate wettability, cohesiveness, adhesiveness, and other adhesive properties, as well as excellent weather resistance and heat resistance.

As the adhesive constituting the adhesive layer, a tackifier, a plasticizer, a filler, an antioxidant, an ultraviolet absorber, a silane coupling agent, and the like can be appropriately used as needed. The thickness of the adhesive layer is preferably 5 μm-100 μm, more preferably 10 μm-50 μm, and more preferably 15 μm-35 μm.

(Anti-Adhesion Hardcoat (ABHC) layer) Since it has the same structure as that of the ABHC layer in the transparent conductive film, detailed description thereof will be omitted. Example

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples. The measuring method of each characteristic in an Example is as follows. In addition, unless otherwise specified, "parts" and "%" in the examples are based on weight.

(1) MIT test The MIT test was performed in accordance with JIS P 8115. Specifically, the base films obtained in Examples and Comparative Examples were cut into lengths of 15 cm and widths of 1.5 cm, and used as measurement samples. Install the test sample (load 1.0kgf, fixture R: 0.38mm) on the MIT bending fatigue tester BE-202 (manufactured by TESTER SANGYO CO,.LTD.), repeat the bending at a test speed of 90cpm and a bending angle of 90° with 500 times as the upper limit, and take the number of times of bending when the test sample breaks as the test value. (2) Folding test The 180° bending test was repeated 100 times on the base films obtained in Examples and Comparative Examples, and the number of times of bending when the sample was broken was measured as the test value. (3) Size shrinkage The thermal shrinkage rates in the longitudinal direction (MD direction) and width direction (TD direction) of the base films obtained in Examples and Comparative Examples were measured as follows. Specifically, the base film was cut into a width of 100 mm and a length of 100 mm (test piece), and four corners were given cross scratches, and the length (mm) before heating in the MD direction and the TD direction of four points in the central part of the cross scratches was measured using a CNC three-dimensional measuring machine (LEGEX774 manufactured by Mitutoyo Corporation). Then, it was thrown into an oven and heat-processed (145 degreeC, 60 minutes). After leaving to cool at room temperature for 1 hour, the length (mm) after heating in the MD direction and the TD direction at 4 points of the four corners was measured again with a CNC three-dimensional measuring machine, and the measured values were substituted into the following formula to obtain the respective heat shrinkage rates in the MD direction and the TD direction. Thermal shrinkage rate (%)=[[length before heating (mm)-length after heating (mm)]/length before heating (mm)]×100 (4) Outgassing The base films obtained in Examples and Comparative Examples were cut into widths of 100 mm and lengths of 100 mm (test pieces), and an adhesive was applied on the side to be bonded to the transparent conductive film and the other side, and the adhesive side was attached to one side of the alkali glass to obtain a test piece. The obtained test piece was put into an autoclave under the conditions of 50° C. and 0.5 atmospheric pressure, and after 15 minutes, the sample was taken out, and those with no bubbles were marked as 0, and those with bubbles were marked as ×. (5) curly The transparent conductive layer film laminates obtained in Examples and Comparative Examples were cut into a size of 20 cm×20 cm. After heating at 145° C. for 60 minutes with the ITO side facing up, it was left to cool at room temperature (23° C.) for 1 hour. Then, the sample was placed on a horizontal surface with the ITO layer facing up, and the height (curl value A) of the central part from the horizontal surface was measured. The heights from the horizontal plane of the four corners were measured respectively, and the average value (curl value B) was calculated. The value (A-B) which subtracted the curl value B from the curl value A was calculated as the curl amount. When the curl value was in the range of 0 mm to 50 mm, it was marked as 0, and in other cases, it was marked as x.

>Example 1> 1-1. Production of transparent conductive film An anti-adhesion hard coat (ABHC) layer was formed on one surface of a polycycloolefin film (trade name "ZEONOR (registered trademark)" manufactured by Zeon Corporation, Japan) with a thickness of 50 μm and a glass transition temperature of 165° C., and a hard coat (HC) layer was formed on the surface opposite to the ABHC layer. An index matching (IM) layer is formed on the surface of the HC layer on the side opposite to the resin film. ITO was sputtered on the surface of the IM layer opposite to the HC layer to form a conductive layer to obtain a transparent conductive film (thickness: 25 μm).

1-2. Polymerization of polyester resin Dimethyl terephthalate was used as a raw material for the monocyclic aromatic polycarboxylic acid component (A1); dimethyl 2,6-naphthalene dicarboxylate was used as a raw material for the polycyclic aromatic polycarboxylic acid component (A2); 9,9-bis(methoxycarbonylethyl)fluorene was used as a raw material for the fluorene-based polycarboxylic acid component (A3); 1,2-propylene glycol was used as a raw material for the aliphatic polyol component (B1); Bis[4-(2-hydroxyethoxy)phenyl]fluorene. Put 15 mol% of (A1) raw material, 50 mol% of (A2) raw material, 55 mol% of (A3) raw material, 10 mol% of (B1) raw material and 90 mol% of (B2) raw material into a stainless steel reaction vessel with a capacity of 30 liters, replace the reaction vessel with nitrogen, and dissolve the raw materials at 150°C. Next, manganese acetate tetrahydrate and calcium acetate monohydrate were added as transesterification catalysts, the temperature was gradually raised to 240°C over 4 hours, and the reaction was continued for 1 hour while maintaining the temperature at 240°C. It was confirmed that by-products were no longer distilled out and predetermined by-products were distilled out. Next, an aqueous solution of trimethyl phosphate and germanium dioxide was prepared and added. Thereafter, temperature rise and pressure reduction were gradually started, and after 90 minutes, the polycondensation reaction proceeded at 270°C and 0.13 kPa, and the reaction was continued until the predetermined torque was reached. After the predetermined torque was reached, the inside of the reaction vessel was pressurized with nitrogen, and the resin was extruded into a bundle in cooling water, and cut to obtain pellets of the polyester-based resin. The glass transition temperature of the obtained polyester resin was 155°C.

1-3. Production of polyester resin film After vacuum-drying the obtained polyester resin at 80° C. for 5 hours, a polyester resin film with a thickness of 100 μm was produced using a film forming device equipped with a single-screw extruder (manufactured by Isuzu Kakoki Co., Ltd., screw diameter: 25 mm, barrel set temperature: 270° C.), a T-die (width 200 mm, set temperature: 270° C.), cooling roll (set temperature: 120° C. to 130° C.), and a coiler.

1-4. Preparation of base film The polyester-based resin film obtained above was simultaneously biaxially stretched twice in the longitudinal direction and the width direction, respectively, to obtain a base film.

1-5. Preparation of carrier film By general solution polymerization, an acrylic polymer having a weight average molecular weight of 600,000 was obtained with butyl acrylate/acrylic acid=100/6 (weight ratio). 6 parts by weight of an epoxy-based crosslinking agent (trade name "TETRAD C (registered trademark)" manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added to 100 parts by weight of the acrylic polymer to prepare an acrylic adhesive. The acrylic adhesive obtained as described above was coated on the release-treated surface of the release-treated PET film, and heated at 120° C. for 60 seconds to form an adhesive layer with a thickness of 20 μm. Next, one side of the base film produced in 1-4. was laminated with a PET film via an adhesive layer. Then, the release-treated PET film was peeled off, and an anti-adhesion hard coat (ABHC) layer was formed on the surface opposite to the adhesive layer to produce a carrier film (thickness: 40 μm).

1-6. Production of transparent conductive thin film laminate The carrier film is temporarily bonded to the surface of the transparent conductive film on the side where the conductive film is not formed through the adhesive layer in a peelable state to form a transparent conductive film laminate. The obtained transparent conductive film laminate was subjected to the evaluations of (4) and (5) above. The results are shown in Table 1.

>Example 2> A transparent conductive film laminate was obtained in the same manner as in Example 1 except that the thickness of the transparent conductive film was 15 μm and the thickness of the carrier film was 25 μm. The obtained transparent conductive film laminate was subjected to the evaluations of (4) and (5) above. The results are shown in Table 1.

>Example 3> A transparent conductive film laminate was obtained in the same manner as in Example 1 except that the thickness of the transparent conductive film was 40 μm and the thickness of the carrier film was 100 μm. The obtained transparent conductive film laminate was subjected to the evaluations of (4) and (5) above. The results are shown in Table 1.

>Example 4> A transparent conductive film laminate was obtained in the same manner as in Example 1 except that the polyester resin obtained in 1-4. was used as the resin film, and the thickness of the transparent conductive film was 25 μm and the thickness of the carrier film was 40 μm. The obtained transparent conductive film laminate was subjected to the evaluations of (4) and (5) above. The results are shown in Table 1.

>Comparative example 1> A transparent conductive film laminate was obtained in the same manner as in Example 1 except that polycarbonate (PC) was used as the carrier film. The obtained transparent conductive film laminate was subjected to the evaluations of (4) and (5) above. The results are shown in Table 1.

>Comparative example 2> A transparent conductive film laminate was obtained in the same manner as in Example 1 except that the thickness of the transparent conductive film was 40 μm, and the thickness of the carrier film was 110 μm using a polyester resin. The obtained transparent conductive film laminate was subjected to the evaluations of (4) and (5) above. The results are shown in Table 1.

>Comparative example 3> A transparent conductive film laminate was obtained in the same manner as in Example 1 except that polycycloolefin-based resin (COP) was used for the carrier film. The obtained transparent conductive film laminate was subjected to the evaluations of (4) and (5) above. The results are shown in Table 1.

[Table 1]

>Evaluation> As is clear from Table 1, the transparent conductive thin film laminates of Examples of the present invention suppressed outgassing and curling. It is presumed that this can be achieved by making the carrier film contain a specific polyester resin whose dimensional change rate when heated at 145° C. for 1 hour is not more than a predetermined value, and the number of MIT times is 500 or more.

Industrial availability The transparent conductive film laminate of the present invention is suitable for use in touch panels.

10: Transparent conductive film 11: Conductive layer 12: Index matching (IM) layer 13: Hard coating (HC) layer 14: Resin film 15: Anti-bonding hard coating (ABHC) layer 20: Carrier film 21: Adhesive layer 22: Base film 23: Anti-bonding hard coating (ABHC) layer 100: transparent conductive film laminate

Fig. 1 is a schematic cross-sectional view of a transparent conductive thin film laminate according to an embodiment of the present invention.

10: Transparent conductive film

11: Conductive layer

12: Index matching (IM) layer

13: Hard coating (HC) layer

14: Resin film

15: Anti-bonding hard coating (ABHC) layer

20: Carrier film

21: Adhesive layer

22: Base film

23: Anti-bonding hard coating (ABHC) layer

100: transparent conductive film laminate

Claims (7)

A transparent conductive film laminate, comprising: a conductive film, which includes a resin film and a conductive film; and a carrier film, which includes a base film containing a polyester resin and an adhesive layer disposed on one side of the base film, and is temporarily bonded to the conductive film in a peelable state through the adhesive layer; the carrier film is laminated on the opposite side of the conductive film; the glass transition temperature (Tg) of the base film is 150° C. The final dimensional shrinkage is 0.2% or less in the first direction and the second direction respectively, the first direction corresponds to the longitudinal direction during manufacture, and the second direction corresponds to the width direction during manufacture, and the number of times the base film is broken in the MIT test according to JIS P 8115 is more than 500 times. A transparent conductive film laminate as in claim 1, wherein the polyester-based resin comprises a polymer of (A) acid component and (B) alcohol component, the (A) component comprises (A1) a monocyclic aromatic polycarboxylic acid component, (A2) a polycyclic aromatic polycarboxylic acid component, and (A3) a fluorene-based polycarboxylic acid component, and the (B) component comprises (B1) an aliphatic polyol component and (B2) a fluorene-based polyol component; relative to the total amount of the (A) component, the content of the (A1) component The rate is 5 mol% or more and less than 30 mol%, the content rate of the (A3) component is 5 mol% or more and 50 mol% or less; the (B2) component does not contain a substantial amount of 9,9-bis(aryl-hydroxy(poly)alkoxyaryl)fluorene component. The transparent conductive film laminate according to claim 2, wherein the component (B2) includes a first fluorene component having two substituents having a hydroxyl group introduced into the 9-position. The transparent conductive thin film laminate according to claim 2, wherein the component (B1) includes a 1,2-propanediol component, and the component (B2) includes a 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene component. The transparent conductive film laminate according to claim 2, wherein the component (A3) includes a second fluorene component having two substituents having carboxyl and/or ester groups introduced at the 9-position. The transparent conductive film laminate according to Claim 2, wherein the component (A1) includes a terephthalic acid component, the component (A2) includes a 2,6-naphthalene dicarboxylic acid component, and the component (A3) includes a 9,9-bis(carboxyethyl)fluorene component. The transparent conductive film laminate according to any one of claims 1 to 6, wherein the thickness of the aforementioned carrier film is 15 μm to 100 μm.