CN111500208A

CN111500208A - Transparent conductive film laminate

Info

Publication number: CN111500208A
Application number: CN202010071683.5A
Authority: CN
Inventors: 中原步梦; 清水享
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp; Denko Corp
Priority date: 2019-01-31
Filing date: 2020-01-21
Publication date: 2020-08-07
Also published as: KR20200095351A; TWI807140B; JP2020121537A; TW202032582A; JP7223586B2

Abstract

Provided is a transparent conductive thin film laminate wherein the occurrence of curling and outgassing is suppressed. A base film having a dimensional shrinkage ratio of 500 or more times and having a small MIT number in both the 1 st direction and the 2 nd direction orthogonal to the 1 st direction is used.

Description

Transparent conductive film laminate

Technical Field

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

Background

Transparent conductive films used for touch panels and the like are practically temporarily bonded to a carrier film to form a laminate, and the laminate is subjected to manufacturing, transportation, storage, and the like. However, in the conventional transparent conductive thin film laminate, curling may occur in the heating step, and the production efficiency may be insufficient.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2017-190406

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made to solve the above-described conventional problems, and an object thereof is to provide a transparent conductive thin film laminate in which occurrence of curl and outgas (outgas) is suppressed.

Means for solving the problems

A transparent conductive thin film laminate according to an embodiment of the present invention includes: a conductive film including a resin film and a conductive film; and a carrier film which has 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 manner via the adhesive layer, wherein the carrier film is laminated on the opposite side of the conductive film to the conductive film, the base film has a glass transition temperature (Tg) of 150 ℃ or more, a dimensional shrinkage rate at 145 ℃ of 0.2% or less in each of a1 st direction and a2 nd direction orthogonal to the 1 st direction, and an MIT number of times of 500 or more.

In 1 embodiment, the polyester resin comprises a polymer of (a) an acid component comprising (a1) a monocyclic aromatic polycarboxylic acid component, (a2) a polycyclic aromatic polycarboxylic acid component, and (A3) a fluorene-based polycarboxylic acid component, and (B) a component comprising (B1) an aliphatic polyol component and (B2) a fluorene-based polyol component, wherein the content of the (a1) component is 5 mol% or more and less than 30 mol%, the content of the (A3) component is 5 mol% or more and 50 mol% or less, and the (B2) component does not contain a substantial amount of 9, 9-bis (aryl-hydroxy (poly) alkoxyaryl) fluorene component.

In 1 embodiment, the component (B2) includes a1 st fluorene component obtained by introducing 2 substituents having a hydroxyl group at the 9-position.

In 1 embodiment, the component (B1) contains a1, 2-propanediol component, and the component (B2) contains a 9, 9-bis [4- (2-hydroxyethoxy) phenyl ] fluorene component.

In 1 embodiment, the component (a3) includes a2 nd fluorene component obtained by introducing 2 substituents having a carboxyl group and/or an ester group at the 9-position.

In 1 embodiment, the component (a1) contains a terephthalic acid component, the component (a2) contains a2, 6-naphthalenedicarboxylic acid component, and the component (A3) contains a 9, 9-bis (carboxyethyl) fluorene component.

In 1 embodiment, the thickness of the carrier film is 15 μm to 100. mu.m.

ADVANTAGEOUS EFFECTS OF INVENTION

According to an embodiment of the present invention, a transparent conductive thin film laminate having a transparent conductive thin film and a carrier thin film, in which a base thin film containing a predetermined polyester-based resin, having a small dimensional shrinkage rate in both the 1 st direction and the 2 nd direction orthogonal to the 1 st direction and having an MIT number of times of 500 or more is used, can be obtained, and occurrence of curl and outgassing can be suppressed.

Drawings

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

Description of the reference numerals

10 transparent conductive film

11 conductive layer

12 Index Matching (IM) layer

13 Hard Coat (HC) layer

14 resin film

15 anti-blocking hardcoat (ABHC) layer

20 carrier film

21 adhesive layer

22 base film

23 anti-blocking hardcoat (ABHC) layer

100 transparent conductive film laminate

Detailed Description

Preferred embodiments of the present invention will be described below, 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 film laminate according to 1 embodiment of the present invention. The transparent conductive film laminate 100 illustrated in the figure has a transparent conductive film 10 and a carrier film 20. The transparent conductive film 10 typically has a resin film 14 and a conductive layer 11. The carrier film 20 typically has a base film 22 and an adhesive layer 21, and is temporarily bonded to the transparent conductive film 10 in a peelable manner by the adhesive layer 21. The carrier film may have an anti-blocking hardcoat (ABHC) layer 23 as desired.

In the embodiment of the present invention, the glass transition temperature (Tg) of the base film 22 is 150 ℃ or higher, preferably 155 ℃ or higher. Further, the dimensional shrinkage of the base film 22 at 145 ℃ is 0.2% or less in each of the 1 st direction and the 2 nd direction orthogonal to the 1 st direction. The 1 st direction corresponds to, for example, an MD direction in a manufacturing method described later, and the 2 nd direction corresponds to, for example, a TD direction. Further, the number of MITs of the base thin film 22 is 500 or more. When the glass transition temperature (Tg), the dimensional shrinkage ratio at 145 ° and the MIT number of the base film 22 are in such ranges, a transparent conductive thin film laminate in which occurrence of curl and outgassing is suppressed can be obtained. Further, the number of times of folding of the base film 22 is preferably 100 or more.

The thickness of the support film 20 is preferably 15 μm to 100 μm, more preferably 15 μm to 80 μm, and still more preferably 15 μm to 60 μm. When the thickness of the carrier film is in such a range, a transparent conductive thin film laminate in which occurrence of curling and outgassing is suppressed can be obtained. The thickness of the carrier film is the total thickness of the base film, the adhesive layer, and, if necessary, the anti-blocking hard coat (ABHC) layer when they 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 visible-side surface of the resin film. The transparent conductive film may have an Index Matching (IM) layer 12, a Hard Coat (HC) layer 13, and/or an anti-blocking hard coat (ABHC) layer 15 as needed.

(resin film)

The resin film may be made of any suitable resin. Examples of the resin constituting the resin film include a cycloolefin resin (COP) and a polyester resin. Details of the cycloolefin resin (COP) are disclosed in, for example, Japanese patent laid-open publication No. 2016-107503. The description of this publication is incorporated herein by reference.

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

(conductive layer)

The conductive layer is typically a transparent conductive layer. The total light transmittance of the conductive layer is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more.

The density of the conductive layer is preferably 1.0g/cm³～10.5g/cm³More preferably 1.3g/cm³～8.0g/cm³。

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

As a representative example of the conductive layer, a conductive layer containing a metal oxide can be cited. Examples of the metal oxide 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 to 0.06. mu.m, more preferably 0.01 to 0.045. mu.m. In the case where the amount is within such a range, a conductive layer having excellent conductivity and light transmittance can be obtained.

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

(refractive Index Matching (IM) layer)

The IM layer may be formed on a side of the conductive layer. Since the IM layer can have a structure known in the art, detailed description thereof is omitted.

(hard coat (HC) layer)

The HC layer may be formed between the IM layer and the resin film. Since the HC layer can have a structure known in the art, detailed description thereof is omitted.

(anti-blocking hardcoat (ABHC) layer)

The ABHC layer may be formed on the opposite surface of the resin film from the HC layer. Details of the ABHC layer are described in, for example, japanese patent laid-open No. 2016-. The description of this publication is incorporated herein by reference.

C. Carrier film

The carrier film 20 comprises an adhesive layer 21 and a base film 22. The carrier film 20 may have an anti-blocking hardcoat (ABHC) layer 23 as desired.

(base film)

The base film according to the embodiment of the present invention is composed of a film containing a polyester resin. The polyester-based resin is typically a polymer containing (a) an acid component and (B) an alcohol component. (A) The component (A) contains a monocyclic aromatic polycarboxylic acid component (A1), a polycyclic aromatic polycarboxylic acid component (A2), and a fluorene polycarboxylic acid component (A3). (B) The component (A) contains (B1) an aliphatic polyol component and (B2) a fluorene polyol component. Typically, the content of the component (a1) is 5 mol% or more and less than 30 mol%, and the content of the component (A3) is 5 mol% or more and 50 mol% or less, based on the total amount of the component (a). (B2) The component (b) is typically free of substantial amounts of 9, 9-bis (aryl-hydroxy (poly) alkoxyaryl) fluorene components.

The monocyclic aromatic polycarboxylic acid component (a1) may contain a component obtained by introducing a plurality of substituents having a carboxyl group into a benzene ring. Examples of the component (a1) include a terephthalic acid component and an isophthalic acid component. (A1) Among the components, terephthalic acid is preferably 50 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more, and further preferably 100 mol%. By using terephthalic acid as a main component, heat resistance can be improved.

The polycyclic aromatic polycarboxylic acid component (a2) may contain a component obtained by introducing a plurality of substituents having a carboxyl group into the naphthalene ring. In the present specification, the component (A3) is not included in the component (A2). Examples of the component (A2) include a2, 6-naphthalenedicarboxylic acid component, a1, 5-naphthalenedicarboxylic acid component, a1, 6-naphthalenedicarboxylic acid component, a1, 7-naphthalenedicarboxylic acid component and a1, 8-naphthalenedicarboxylic acid component. (A2) Among the components, the 2, 6-naphthalenedicarboxylic acid component is preferably 50 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more, and further preferably 100 mol%. The heat resistance can be improved by mainly using a2, 6-naphthalenedicarboxylic acid component.

The fluorene-based polycarboxylic acid component (a3) may contain a component obtained by introducing a plurality of substituents having a carboxyl group into fluorene. An example of the chemical formula of the fluorene-based polycarboxylic acid component is shown in chemical formula 1 below. (A3) The component (b) may include, for example, a component obtained by introducing 2 substituents having a carboxyl group and/or an ester group at the 9-position of fluorene. In chemical formula 1, R¹And R²The same substituents may be used. R¹And R²For example, carboxyalkyl (- (CH)₂)_nCOOH). Examples of the component (a3) include a 9, 9-bis (carboxyethyl) fluorene component represented by the following chemical formula 2. (A3) Among the components, the 9, 9-bis (carboxyethyl) fluorene component is preferably 50 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more, and further preferably 100 mol%. By mainly using a 9, 9-bis (carboxyethyl) fluorene component, birefringence can be reduced, and as a result, a base film having a desired in-plane retardation can be obtained.

(A1) The content of the component (b) is preferably 5 mol% or more, more preferably 8 mol% or more, and further preferably 10 mol% or more based on the total amount of the acid component. When the content of the component (A1) is less than 5 mol%, birefringence may be increased. (A1) The content of the component (b) is preferably less than 30 mol%, more preferably 29 mol% or less, and further preferably 28 mol% or less, based on the total amount of the acid component. If the content of the component (a1) is 30 mol% or more, the heat resistance may be insufficient.

(A2) The content of the component (b) is preferably 25 mol% or more, more preferably 30 mol% or more, and further preferably 35 mol% or more based on the total amount of the acid component. If the content of the component (A2) is less than 25 mol%, the heat resistance may be insufficient. (A2) The content of the component (b) is preferably 70 mol% or less, more preferably 60 mol% or less, and further preferably 55 mol% or less, based on the total amount of the acid components. When the content of the component (A2) exceeds 70 mol%, birefringence may increase.

(A3) The content of the component (b) is preferably 5 mol% or more, more preferably 10 mol% or more, and further preferably 15 mol% or more based on the total amount of the acid component. When the content of the component (A3) is less than 5 mol%, birefringence may be increased. (A3) The content of the component (b) is preferably 50 mol% or less, more preferably 45 mol% or less, and further preferably 40 mol% or less, based on the total amount of the acid component. If the content of the component (a3) exceeds 50 mol%, the heat resistance may be insufficient.

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

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

The fluorene-based polyol component may contain a component obtained by introducing a plurality of substituents having a hydroxyl group into fluorene. An example of the chemical formula of the fluorene-based polyol component is shown in chemical formula 3 below. (B2) The component (b) may include, for example, a component obtained by introducing 2 substituents having a hydroxyl group into the 9-position of fluorene. In chemical formula 3, R³And R⁴The same substituents may be used. R³And R⁴For example, hydroxyalkoxyaryl groups may be used. The component (B2) includes, for example, 9-bis [4- (2-hydroxyethoxy) phenyl group]Fluorene component, 9-bis [4- (2-hydroxyethoxy) -3-methylphenyl]Fluorene component, 9-bis [4- (2-hydroxyethoxy) -3, 5-dimethylphenyl]Fluorene component, 9-bis [4- (2-hydroxyethoxy) -3, 5-diethylphenyl group]A fluorene component, and the like. Among them, the component (B2) is particularly preferably 9, 9-bis [4- (2-hydroxyethoxy) phenyl ] represented by the following chemical formula 4]A fluorene component. (B2) In the component (A), 9, 9-bis [4- (2-hydroxyethoxy) phenyl]The fluorene component is preferably 50 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more, and further preferably 100 mol%. By reacting 9, 9-bis [4- (2-hydroxyethoxy) phenyl]The fluorene component is mainly contained, so that the heat resistance of the obtained base film can be improved and the birefringence (as a result, in-plane retardation) can be reduced. In particular, 9, 9-bis [4- (2-hydroxyethoxy) phenyl group in the component (B2)]The fluorene component is more preferably 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more, and still more preferably 100 mol%.

(B2) The component (b) preferably does not contain a substantial amount of a 9, 9-bis (aryl-hydroxy (poly) alkoxyaryl) fluorene component. As the 9, 9-bis (aryl-hydroxy (poly) alkoxyaryl) fluorene component, for example, a 9, 9-bis [4- (2-hydroxyethoxy) -3-phenylphenyl ] fluorene component represented by the following chemical formula 5 can be cited. When the 9, 9-bis (aryl-hydroxy (poly) alkoxyaryl) fluorene component is contained, mechanical properties and/or moldability may be insufficient. Here, the "substantial amount" means an amount that can produce the effect of the 9, 9-bis (aryl-hydroxy (poly) alkoxyaryl) fluorene component.

(B1) The content of the component (b) is preferably 3 mol% or more, more preferably 5 mol% or more, and further preferably 8 mol% or more based on the total amount of the alcohol component. If the content of the component (B1) is less than 3 mol%, the mechanical properties and/or moldability may be insufficient. (B1) The content of the component (b) is preferably 30 mol% or less, more preferably 20 mol% or less, and still more preferably 15 mol% or less, based on the total amount of the alcohol component. If the content of the component (B1) exceeds 30 mol%, the heat resistance may be insufficient.

(B2) The content of the component (b) is preferably 70 mol% or more, more preferably 80 mol% or more, and further preferably 85 mol% or more based on the total amount of the alcohol component. If the content of the component (B2) is less than 70 mol%, the heat resistance may be insufficient. (B2) The content of the component (b) is preferably 97 mol% or less, more preferably 95 mol% or less, and still more preferably 92 mol% or less, based on the total amount of the alcohol component. If the content of the component (B2) exceeds 97 mol%, the mechanical properties and/or moldability may be insufficient.

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

Details of polyester resins are described in, for example, Japanese patent laid-open publication No. 2018-168210. The description of this publication is incorporated herein by reference.

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

The elastic modulus of the base film is preferably 50MPa to 350MPa at a stretching speed of 100 mm/min. When the elastic modulus is in such a range, a base film excellent in transportability and handling properties can be obtained. According to the embodiments of the present invention, excellent elastic modulus (strength) and excellent flexibility or bending resistance (flexibility) as described above can be achieved at the same time. The elastic modulus was measured in accordance with JIS K7127: 1999.

The tensile elongation of the base film is preferably 70% to 200%. When the tensile elongation is in such a range, there is an advantage that the sheet is not easily broken during conveyance. The tensile elongation is measured according to JIS K6781.

(method for producing base film)

The method for manufacturing a base film according to an embodiment of the present invention includes: a film-forming material (resin composition) comprising the polyester resin as described in the above A is formed into a film and the formed film is stretched.

The film-forming material may contain other resins than the polyester-based resin, additives, or solvents as described above. As the additive, any suitable additive may be used according to the purpose. Specific examples of the additives include reactive diluents, plasticizers, surfactants, fillers, antioxidants, anti-aging agents, ultraviolet absorbers, leveling agents, thixotropic agents, antistatic agents, conductive materials, and flame retardants. The amount, kind, combination, addition amount, and the like 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 molding process may be employed. Specific examples thereof include compression molding, transfer molding, injection molding, extrusion molding, blow molding, powder molding, FRP molding, cast coating (for example, casting), calendering, and hot pressing. Extrusion or cast coating is preferred. This is because the smoothness of the obtained film can be improved and good optical uniformity can be obtained. The molding conditions may be appropriately set depending on the composition and type of the resin used, the desired properties of the base film, and the like.

The stretching method of the film 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. The sequential biaxial stretching or simultaneous biaxial stretching is typically performed using a tenter. Therefore, the stretching direction of the film is typically the longitudinal direction and the width direction of the film.

The stretching temperature may vary depending on the in-plane retardation and thickness desired for the base film, the type of resin used, the thickness of the film used, the stretching ratio, and the like. Specifically, the stretching temperature is preferably from Tg +5 ℃ to Tg +50 ℃ and more preferably from Tg +10 ℃ to Tg +40 ℃ relative to the glass transition temperature (Tg) of the film. By stretching at such a temperature, embodiments of the present invention can provide a base film having appropriate characteristics.

The stretch ratio may vary depending on the in-plane retardation and thickness desired for the base film, the type of resin used, the thickness of the film used, the stretching temperature, and the like. In the case of biaxial stretching (for example, sequential biaxial stretching or simultaneous biaxial stretching), the difference between the stretch ratio in the 1 st direction (for example, the longitudinal direction) and the stretch ratio in the 2 nd direction (for example, the width direction) is preferably 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. In the case of biaxial stretching (for example, sequential biaxial stretching or simultaneous biaxial stretching), the stretching magnification may be, for example, 1.1 times to 3.0 times in each of the 1 st direction (for example, the longitudinal direction) and the 2 nd direction (for example, the width direction).

In the embodiment of the present invention, the stretching speed is preferably 10%/second or less, more preferably 7%/second or less, further preferably 5%/second or less, and particularly preferably 2.5%/second or less. By stretching a film comprising the specific polyester resin as described above at such a low stretching speed, a base film having a small in-plane retardation can be obtained. The lower limit of the drawing speed may be, for example, 1.2%/second. If the stretching speed is too low, the productivity may become impractical. In the case of biaxial stretching (for example, sequential biaxial stretching or simultaneous biaxial stretching), the difference between the stretching speed in the 1 st direction (for example, the longitudinal direction) and the stretching speed in the 2 nd direction (for example, the width direction) is preferably as small as possible, and more preferably substantially equal. With such a configuration, the in-plane retardation Re (550) of the base film can be reduced.

(adhesive layer)

The pressure-sensitive adhesive layer may be used without particular limitation as long as it has transparency. Specifically, for example, those based on a rubber-based polymer such as an acrylic polymer, a silicone polymer, a polyester, a polyurethane, a polyamide, a polyvinyl ether, a vinyl acetate/vinyl chloride copolymer, a modified polyolefin, an epoxy-based, a fluorine-based, a natural rubber, or a synthetic rubber can be suitably selected and used. In particular, acrylic pressure-sensitive adhesives are preferably used because they are excellent in optical transparency, exhibit appropriate adhesive properties such as wettability, cohesion and adhesiveness, and are also excellent in weather resistance and heat resistance.

If necessary, a tackifier, a plasticizer, a filler, an antioxidant, an ultraviolet absorber, a silane coupling agent, and the like may be suitably used for the adhesive constituting the adhesive layer. The thickness of the pressure-sensitive adhesive layer is preferably 5 to 100. mu.m, more preferably 10 to 50 μm, and still more preferably 15 to 35 μm.

(anti-blocking hardcoat (ABHC) layer)

Since the transparent conductive film has the same structure as the ABHC layer, detailed description thereof will be omitted.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The measurement methods of the characteristics in the examples are as follows. Unless otherwise specified, "parts" and "%" in the examples are based on weight.

(1) MIT test

More specifically, the base films obtained in examples and comparative examples were cut into pieces having a length of 15cm and a width of 1.5cm, and used as measurement samples, the measurement samples were mounted (load: 1.0kgf, R: 0.38mm of jig) on an MIT bending fatigue TESTER BE-202 type (TESTER SANGYO CO, manufactured by L TD.), and bending was repeated at a test speed of 90cpm and a bending angle of 90 degrees, with 500 times as upper limits, and the number of times of bending when the measurement samples broke was used as a test value.

(2) Folding endurance test

The base films obtained in examples and comparative examples were subjected to a 180 ° bending test 100 times, and the number of times of bending when the test sample was broken was determined as a test value.

(3) Dimensional shrinkage

Specifically, the base film obtained in examples and comparative examples was cut into a width of 100mm and a length of 100mm (test piece), a cross-shaped scratch was applied to 4 corners, the length (mm) before heating in the MD direction and the TD direction of 4 points in the center of the cross-shaped scratch was measured by a CNC three-dimensional measuring machine (L EGEX774 manufactured by Mitutoyo Corporation), the base film was put into an oven and subjected to a heating treatment (145 ℃ for 60 minutes), the base film was left to cool at room temperature for 1 hour, and then the heated lengths (mm) in the MD direction and the TD direction of 4 points in the 4 corners were measured again by the CNC three-dimensional measuring machine, and the measured values were substituted into the following formulae to determine the respective heat shrinkage ratios in the MD direction and the TD direction.

Heat shrinkage (%) of [ [ length before heating (mm) -length after heating (mm) ]/length before heating (mm) ] × 100

(4) Exhaust of gases

The base films obtained in examples and comparative examples were cut into pieces (test pieces) having a width of 100mm and a length of 100mm, the adhesive was applied to the surface to be bonded to the transparent conductive film and the other surface, and the adhesive surface was attached to one surface of alkali glass to obtain test pieces, the obtained test pieces were put into an autoclave at 50 ℃ under a pressure of 0.5 atm, a sample was taken out after 15 minutes, and the piece having no bubbles was visually recognized was regarded as good, and the piece having bubbles was regarded as ×.

(5) Crimping

The transparent conductive layer film laminates obtained in examples and comparative examples were cut into a size of 20cm × 20cm, heated at 145 ℃ for 60 minutes with the ITO layer facing upward, then allowed to cool at room temperature (23 ℃) for 1 hour, then the sample was placed on a horizontal surface with the ITO layer facing upward, the height of the central portion from the horizontal plane (curl value a) was measured, the heights of the 4 corners from the horizontal plane were measured, the average value (curl value B) was calculated, the value (a-B) obtained by subtracting the curl value B from the curl value a was calculated as the curl amount, and the value when the curl value was in the range of 0mm to 50mm was recorded as the value (g), and the other value was recorded as ×.

< example 1>

1-1 preparation of transparent conductive film

An anti-blocking hard coat (ABHC) layer was formed on the surface of one side of a polycycloolefin film (trade name "ZEONOR (registered trademark)", manufactured by Zeon Corporation) having a thickness of 50 μm and a glass transition temperature of 165 ℃, and a Hard Coat (HC) layer was formed on the surface opposite to the ABHC layer. A refractive Index Matching (IM) layer is formed on the surface of the HC layer on the side opposite to the resin film. An ITO layer was sputtered on the surface of the IM layer opposite to the HC layer to form a conductive layer, thereby obtaining a transparent conductive thin film (thickness: 25 μm).

1-2 polymerization of polyester-series resin

Dimethyl terephthalate was used as a raw material of the monocyclic aromatic polycarboxylic acid component (a 1); dimethyl 2, 6-naphthalenedicarboxylate as a raw material for the polycyclic aromatic polycarboxylic acid component (A2); 9, 9-bis (methoxycarbonylethyl) fluorene was used as a raw material of the fluorene-based polycarboxylic acid component (a 3); 1, 2-propanediol was used as a raw material of the aliphatic polyol component (B1); as a raw material of the fluorene-based polyol component (B2), 9-bis [4- (2-hydroxyethoxy) phenyl ] fluorene was used. 15 mol% of the (A1) raw material, 50 mol% of the (A2) raw material, 55 mol% of the (A3) raw material, 10 mol% of the (B1) raw material, and 90 mol% of the (B2) raw material were charged into a 30-liter stainless steel reaction vessel, the interior of the reaction vessel was replaced with nitrogen, and the raw materials were dissolved at 150 ℃. Subsequently, manganese acetate tetrahydrate and calcium acetate monohydrate were added as transesterification catalysts, and the temperature was gradually raised to 240 ℃ over 4 hours, and the reaction was continued for 1 hour while maintaining the temperature at 240 ℃. It was confirmed that the by-product was not distilled any more and that a predetermined by-product was distilled off. Subsequently, an aqueous solution of trimethyl phosphate and germanium dioxide was prepared and added. Then, the temperature rise and the pressure reduction were gradually started, and 90 minutes later, the temperature reached 270 ℃ and 0.13kPa, and the polycondensation reaction was continued in this state until the predetermined torque was reached. After reaching a predetermined torque, the inside of the reaction vessel was pressurized with nitrogen gas, and the resin was extruded into strands in cooling water and cut to obtain polyester resin pellets. The glass transition temperature of the obtained polyester resin was 155 ℃.

1-3 preparation of polyester resin film

The obtained polyester resin was vacuum-dried at 80 ℃ for 5 hours, and then a polyester resin film having a thickness of 100 μm was produced using a film forming apparatus equipped with a single-screw extruder (manufactured by Isuzu Kakoki Co., Ltd., screw diameter: 25mm, cylinder set temperature: 270 ℃), T-die (width: 200mm, set temperature: 270 ℃), chill roll (set temperature: 120 ℃ C. -130 ℃ C.), and winder.

1-4. production of base film

The polyester resin film obtained in the above was simultaneously biaxially stretched 2 times in the longitudinal direction and the width direction, respectively, to obtain a base film.

1-5 preparation of Carrier film

An acrylic polymer having a weight-average molecular weight of 60 ten thousand was obtained as butyl acrylate/acrylic acid (weight ratio) of 100/6 by ordinary solution polymerization. To 100 parts by weight of this acrylic polymer, 6 parts by weight of an epoxy crosslinking agent (trade name "TETRAD C (registered trademark)" manufactured by mitsubishi gas chemical corporation) was added to prepare an acrylic adhesive. The acrylic pressure-sensitive adhesive obtained as described above was applied to the release-treated surface of the release-treated PET film, and heated at 120 ℃ for 60 seconds to form a pressure-sensitive adhesive layer having a thickness of 20 μm. Subsequently, a PET film was laminated on one surface of the base film produced in 1-4 through an adhesive layer. Then, the release-treated PET film was peeled off, and an anti-blocking hard coat (ABHC) layer was formed on the surface opposite to the pressure-sensitive adhesive layer, thereby producing a carrier film (thickness: 40 μm).

1-6 preparation of transparent conductive film laminate

The transparent conductive film laminate is formed by temporarily bonding a carrier film to the surface of the transparent conductive film on the side where the conductive film is not formed, in a releasable manner via an adhesive layer. The obtained transparent conductive thin film laminate was subjected to the evaluations (4) and (5). The results are shown in Table 1.

< example 2>

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

< example 3>

A transparent conductive thin film laminate was obtained in the same manner as in example 1, except that the thickness of the transparent conductive thin film was 40 μm and the thickness of the carrier thin film was 100 μm. The obtained transparent conductive thin film laminate was subjected to the evaluations (4) and (5). 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-based resin obtained in item 1 to 4 was used as the resin film, and the thickness of the transparent conductive film was set to 25 μm, and the thickness of the carrier film was set to 40 μm. The obtained transparent conductive thin film laminate was subjected to the evaluations (4) and (5). 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 thin film laminate was subjected to the evaluations (4) and (5). 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, the thickness of the carrier film was 110 μm, and the thickness of the carrier film was polyester resin. The obtained transparent conductive thin film laminate was subjected to the evaluations (4) and (5). 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 a polycycloolefin resin (COP) was used as the carrier film. The obtained transparent conductive thin film laminate was subjected to the evaluations (4) and (5). The results are shown in Table 1.

[ Table 1]

< evaluation >

As is clear from table 1, the transparent conductive film laminate of the examples of the present invention suppressed the occurrence of outgassing and curling. This is presumably achieved by including a specific polyester resin in the carrier film, and setting the polyester resin to have a dimensional change rate of not more than a predetermined value and an MIT number of not less than 500 times when heated at 145 ℃ for 1 hour.

Industrial applicability

The transparent conductive film laminate of the present invention is suitably used for a touch panel.

Claims

1. A transparent conductive thin film laminate comprising:

a conductive film including a resin film and a conductive film; and

a carrier film which has 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 manner via the adhesive layer,

the carrier film is laminated on the opposite side of the conductive film from the conductive film,

the base film has a glass transition temperature (Tg) of 150 ℃ or higher, a dimensional shrinkage rate at 145 ℃ of 0.2% or lower in each of a1 st direction and a2 nd direction orthogonal to the 1 st direction, and an MIT number of 500 or more.

2. The transparent conductive film laminate according to claim 1, wherein the polyester-based resin comprises a polymer of (A) an acid component and (B) an alcohol component,

the component (A) comprises a monocyclic aromatic polycarboxylic acid component (A1), a polycyclic aromatic polycarboxylic acid component (A2), and a fluorene polycarboxylic acid component (A3),

the component (B) comprises (B1) an aliphatic polyol component and (B2) a fluorene-based polyol component,

the content of the component (A1) is 5 mol% or more and less than 30 mol%, and the content of the component (A3) is 5 mol% or more and 50 mol% or less,

the component (B2) does not contain a substantial amount of 9, 9-bis (aryl-hydroxy (poly) alkoxyaryl) fluorene component.

3. The transparent conductive thin film laminate according to claim 2, wherein the component (B2) comprises a1 st fluorene component obtained by introducing 2 substituents having a hydroxyl group into the 9-position.

4. The transparent conductive film laminate according to claim 2 or 3, wherein the component (B1) contains a1, 2-propanediol component, and the component (B2) contains a 9, 9-bis [4- (2-hydroxyethoxy) phenyl ] fluorene component.

5. The transparent conductive thin film laminate according to any one of claims 2 to 4, wherein the component (A3) contains a2 nd fluorene component obtained by introducing 2 substituents having a carboxyl group and/or an ester group into the 9-position.

6. The transparent conductive film laminate according to any one of claims 2 to 5, wherein the component (A1) comprises a terephthalic acid component, the component (A2) comprises a2, 6-naphthalenedicarboxylic acid component, and the component (A3) comprises a 9, 9-bis (carboxyethyl) fluorene component.

7. The transparent conductive thin film laminate according to any one of claims 1 to 6, wherein the thickness of the support thin film is 15 μm to 100 μm.