Crystalline transparent conductive film support film, transparent conductive laminate, and device

Abstract

The present invention provides a film used as a support for forming a crystalline transparent conductive film, which exhibits excellent transparency and dimensional stability even under high-temperature conditions of 200°C or higher. [Solution] The film of the present invention is a film used as a support when forming a crystalline transparent conductive film by depositing a transparent conductive material and heat-treating it at a temperature of 200°C or higher, and contains a semi-aromatic polyamide as a resin component, and after heat treatment at 200°C for 15 minutes, the thermal shrinkage rate in the MD direction and TD direction is -0.20% to 0.20%, respectively, and the total light transmittance measured in accordance with JIS K7136 is 85.0% or higher.

Description

[Technical Field]

[0001] The present invention relates to a film used as a support when forming a crystalline transparent conductive film, a transparent conductive laminate including a structure in which a crystalline transparent conductive film is laminated on the film, a device including the transparent conductive laminate, and a method for producing the transparent conductive laminate. [Background Art]

[0002] In recent years, transparent conductive films such as ITO (Indium Tin Oxide) films have become one of the main components in devices such as solar cells, displays, and touch panels.

[0003] Among transparent conductive films, for example, for ITO films, a sputtering method in which ITO is vapor-deposited on a support to form a film is most widely used industrially.

[0004] Patent Document 1 describes that a COP (cycloolefin polymer) substrate whose surface is protected by a PET film is used as a support for an ITO film.

[0005] Further, Patent Document 2 describes that a PEN (polyethylene naphthalate) film is used as a support for an ITO film. [Prior Art Documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent No. 6672819 [Patent Document 2] Japanese Patent No. 7162461 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] When an ITO film is deposited by vapor deposition, an amorphous or low-crystallinity ITO film is formed. By applying heat treatment after deposition to increase the degree of crystallinity, an ITO film with transparency and conductivity can be obtained. In this heat treatment, the higher the treatment temperature and the longer the treatment time, the higher the degree of crystallinity of the ITO film, and the better the transparency and conductivity.

[0008] However, while the COP substrate with a PET film surface protection described in Patent Document 1 and the PEN film described in Patent Document 2 exhibit dimensional stability in temperature atmospheres below 150°C, their thermal shrinkage rate increases sharply in temperature atmospheres above 150°C, resulting in a large difference with the thermal shrinkage rate of the ITO film and making the ITO film prone to cracking. Therefore, heat treatment cannot be performed at high temperatures above 150°C, making it difficult to sufficiently increase the degree of crystallinity. Furthermore, the inability to perform rapid heat treatment at high temperatures results in poor work efficiency.

[0009] Furthermore, the PEN film is prone to increased haze and reduced transparency due to heat treatment. Therefore, when a laminate of PEN film and ITO film, obtained using PEN film as a support, is used as a transparent electrode in a display, the display becomes unclear, which is a problem.

[0010] Therefore, the object of the present invention is to provide a film used as a support for forming a crystalline transparent conductive film, which exhibits excellent transparency and dimensional stability even under high temperature conditions of 200°C or higher. Another object of the present invention is to provide a transparent conductive laminate having a laminated structure of the film and a crystalline transparent conductive film. Another object of the present invention is to provide a device comprising the transparent conductive laminate. Another object of the present invention is to provide a method for manufacturing the transparent conductive laminate. [Means for solving the problem]

[0011] As a result of diligent research to solve the above problems, the inventors have found that a film obtained by subjecting an unstretched film containing a semi-aromatic polyamide as a resin component to stretching and relaxing treatments in the MD and TD directions at specific ratios can suppress the increase in haze value and deformation even under high temperature conditions of 200°C or higher, and even when the film is thickened to create a temperature difference between the surface and the depths of the film. Furthermore, they have found that by using the aforementioned film as a support, a crystalline transparent conductive material film with high crystallinity, excellent transparency and conductivity can be rapidly formed while suppressing the occurrence of cracks by depositing a transparent conductive material onto the film and heat-treating it at high temperatures. The present invention was completed based on these findings.

[0012] In other words, the present invention relates to a film used as a support when forming a crystalline transparent conductive film by depositing a transparent conductive material and heat-treating it at a temperature of 200°C or higher, The resin component contains a semi-aromatic polyamide. The present invention provides a film in which, after heat treatment at 200°C for 15 minutes, the thermal shrinkage rates in the MD direction and TD direction are -0.20% to 0.20%, respectively, and the total light transmittance measured in accordance with JIS K7136 is 85.0% or higher.

[0013] The present invention also provides a film having a haze value of 0.20% or less per 1 μm of film thickness, measured in accordance with JIS K7136, after heat treatment at 200°C for 15 minutes.

[0014] The present invention also provides the film wherein the semi-aromatic polyamide is a compound having repeating units represented by the following formula (pa-1).

[0015] [ka] (In the formula, R represents a divalent hydrocarbon group containing an aromatic hydrocarbon ring, and n represents an integer between 6 and 12.)

[0016] The present invention also provides the film in which the semi-aromatic polyamide is polyamide 9T.

[0017] The present invention also provides a transparent conductive laminate having a laminated structure of the film and a crystalline transparent conductive film.

[0018] The present invention also provides a transparent conductive laminate in which the crystalline transparent conductive film is a crystalline ITO film.

[0019] The present invention also provides a device comprising the transparent conductive laminate.

[0020] The present invention also produces a film in which, after undergoing the stretching and relaxation processes described below and heat treatment at 200°C for 15 minutes, the thermal shrinkage rates in the MD and TD directions are -0.20% to 0.20%, respectively, and the total light transmittance measured in accordance with JIS K7136 is 85.0% or higher. The present invention provides a method for manufacturing a transparent conductive laminate, which involves laminating a vapor-deposited film of a transparent conductive material onto a generated film, and then heat-treating the film with the vapor-deposited film laminated on it at a temperature of 100°C or higher to obtain a transparent conductive laminate having a laminated structure of the film and a crystalline transparent conductive film. Stretching process: An unstretched film containing semi-aromatic polyamide as a resin component is stretched in the MD direction at a stretch ratio (E MD ) Stretching process of 2 to 3.5 times, and stretching ratio (E) in the TD direction TD ) Apply a stretching treatment to increase the material's length by 2 to 4 times. Relaxation process: After the stretching process is completed, the film is subjected to a relaxation process in the MD direction (R MD )2-8% relaxation treatment and relaxation rate (R) in the TD direction TD ) Apply a relaxation treatment of 1.5-6%.

[0021] The present invention also relates to the stretching ratio (E) in the MD direction. MD ), TD direction stretching ratio (E TD ), relaxation rate in the MD direction (R MD ), and the relaxation rate in the TD direction (R TD The present invention provides a method for manufacturing the transparent conductive laminate that satisfies the following formulas (1) to (3). 1.0≦E TD / E MD ≦1.5 (1) 1.1≦R MD / E MD ≦2.3 (2) 0.5≦R TD / E TD ≦1.3 (3) Advantageous Effects of Invention

[0022] The film of the present invention can maintain excellent transparency (hereinafter sometimes referred to as "heat-resistant transparency") and excellent dimensional stability (hereinafter sometimes referred to as "thermal dimensional stability") even under high-temperature conditions. Therefore, when the film is used as a support for forming a transparent conductive film, the transparent conductive film laminated on the film can be subjected to high-temperature treatment, whereby the crystallinity of the transparent conductive film can be increased in a short time, resulting in excellent working efficiency. Therefore, the film of the present invention can be suitably used as a support for producing transparent electrodes, transparent conductive layers, transparent substrates, biosensors and the like used in devices such as solar cells, displays, and touch panels.

[0023] Further, the transparent conductive laminate of the present invention is produced using a film excellent in heat-resistant transparency and thermal dimensional stability as a support. Therefore, the crystalline transparent conductive film included in the transparent conductive laminate has no cracks, and is excellent in transparency and conductivity. Since the transparent conductive laminate has the above properties, it can be suitably used as a transparent electrode, a transparent conductive layer, a transparent substrate, a biosensor or the like used in devices such as solar cells, displays, and touch panels.

[0024] Furthermore, according to the method for producing a transparent conductive laminate of the present invention, an unstretched film containing semi-aromatic polyamide as a resin component is subjected to specific stretching treatment and relaxation treatment to produce a film excellent in heat resistance (that is, heat-resistant transparency and thermal dimensional stability), and by using the produced film as a support, a transparent conductive laminate excellent in transparency and conductivity can be produced with good yield. Mode for Carrying Out the Invention

[0025] [film] The film of the present invention is a film used as a support when forming a crystalline transparent conductive film by depositing a transparent conductive material and heat-treating it at a temperature of 200°C or higher. The film has the following characteristics.

[0026] (thermal dimensional stability) The aforementioned film exhibits excellent thermal dimensional stability, and its thermal shrinkage rate in the MD direction (S) after heat treatment at 200°C for 15 minutes is excellent. MD ) and thermal shrinkage coefficient in the TD direction (S TD ) are both -0.20% to 0.20%. Thermal shrinkage rate (S MD ), thermal shrinkage rate (S TD The lower limit of ) is preferably -0.10%, and more preferably 0%. The lower limit may be even lower, up to 0.05%. Heat shrinkage rate (S MD ), thermal shrinkage rate (S TD The upper limit of ) is preferably 0.15%, and more preferably 0.1%.

[0027] Furthermore, the thermal shrinkage rate (S) in the MD direction of the film after heat treatment at 150°C for 30 minutes is measured. MD ) and thermal shrinkage coefficient in the TD direction (S TD It is preferable that both values ​​are -0.20% to 0.20%. Thermal shrinkage rate (S MD ), thermal shrinkage rate (S TD The lower limit of ) is more preferably -0.10%, and particularly preferably 0%. The lower limit may be even more preferably 0.05%. Thermal shrinkage rate (S MD ), thermal shrinkage rate (S TD The upper limit of ) is more preferably 0.15%, and particularly preferably 0.1%.

[0028] If the film has a thermal shrinkage rate within the range described above, when the film is used as a support when forming a crystalline transparent conductive film by depositing a transparent conductive material and heat-treating it at a temperature of 200°C or higher, the difference in dimensional change between the film and the crystalline transparent conductive film can be suppressed, and cracks in the crystalline transparent conductive film due to the difference in dimensional change can be prevented.

[0029] (Heat-resistant transparency) The film exhibits excellent heat resistance and transparency, and its total light transmittance (measured according to JIS K7136) after heat treatment at 200°C for 15 minutes is 85.0% or higher. A total light transmittance of 87.0% or higher is more preferable, 88.0% or higher is even more preferable, and 89.0% or higher is particularly preferable. Because the film possesses the aforementioned optical properties, it exhibits excellent transparency, and excellent visibility can be obtained when the film is used in displays or the like.

[0030] (Hayes) The film exhibits excellent transparency, and after heat treatment at 200°C for 15 minutes, the haze value per 1 μm of film thickness (the haze value measured according to JIS K7136 divided by the film thickness) is 0.20% or less (for example, 0.01 to 0.20%). Preferably, the haze value per 1 μm of film thickness is 0.15% or less, and more preferably 0.13%. Because the film has the optical properties described above, when the film is used in a display or the like, an image can be displayed clearly, and excellent visibility can be obtained.

[0031] (Thickness) The thickness of the film is not particularly limited, but from the viewpoint of strength, it is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 25 μm or more. Furthermore, from the viewpoint of transparency and thermal dimensional stability, the thickness is preferably 75 μm or less, more preferably 60 μm or less, and even more preferably 40 μm or less.

[0032] (Resin components) The aforementioned film contains a semi-aromatic polyamide as a resin component.

[0033] Semi-aromatic polyamides are compounds obtained by a dehydration condensation reaction between a dicarboxylic acid component and a diamine component, and have at least repeating units derived from the dicarboxylic acid component and repeating units derived from the diamine component. The dicarboxylic acid component and the diamine component may each contain one compound alone or two or more compounds in combination. Semi-aromatic polyamides contain an aromatic compound in either the dicarboxylic acid component or the diamine component.

[0034] Dicarboxylic acid components include aliphatic dicarboxylic acids and aromatic dicarboxylic acids.

[0035] Examples of the aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanediic acid, tetradecanediic acid, and octadecanediic acid.

[0036] Examples of the aforementioned aromatic dicarboxylic acids include terephthalic acid (TPA), isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, and 4,4'-diphenyl etherdicarboxylic acid.

[0037] Furthermore, the naphthalenedicarboxylic acid includes 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and the like. The diphenyldicarboxylic acid includes 4,4'-diphenyldicarboxylic acid, 3,3'-diphenyldicarboxylic acid, 2,2'-diphenyldicarboxylic acid, and the like.

[0038] Diamine components include aliphatic diamines, alicyclic diamines, and aromatic diamines.

[0039] Examples of the aliphatic diamines include linear aliphatic diamines such as 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine (NDA), 1,10-decanediamine (DDA), 1,11-undecanediamine, and 1,12-dodecanediamine; and branched aliphatic diamines such as 2-methyl-1,8-octanediamine (MODA), 4-methyl-1,8-octanediamine, 5-methyl-1,9-nonanediamine, 2,2,4(2,4,4)-trimethyl-1,6-hexanediamine, 2-methyl-1,5-pentanediamine, 2-methyl-1,6-hexanediamine, and 2-methyl-1,7-heptanediamine.

[0040] Examples of the alicyclic diamines include isophorone diamine, norbornane dimethylamine, and tricyclodecane dimethylamine.

[0041] Examples of the aforementioned aromatic diamines include metaxylylenediamine, p-xylylenediamine, m-phenylenediamine, and p-phenylenediamine.

[0042] As a semi-aromatic polyamide, it is preferable that the dicarboxylic acid component contains an aromatic dicarboxylic acid, is particularly preferable to contain terephthalic acid and / or naphthalenedicarboxylic acid, and is most preferable to contain terephthalic acid, in terms of excellent heat resistance, transparency, and thermal dimensional stability.

[0043] The proportion of terephthalic acid and / or naphthalenedicarboxylic acid in the total amount of the dicarboxylic acid component (the total proportion if two or more are included) is preferably 60 mol% or more, more preferably 70 mol% or more, and even more preferably 85 mol% or more, in order to obtain a film with excellent heat resistance, low water absorption, and excellent water resistance.

[0044] The diamine component preferably contains an aliphatic diamine in terms of excellent heat resistance, transparency, and thermal dimensional stability, and more preferably contains an aliphatic diamine having 6 to 12 carbon atoms (the lower limit is preferably 7, more preferably 8, and even more preferably 9; the upper limit is preferably 11, and even more preferably 10).

[0045] The proportion of aliphatic diamines in the total amount of the diamine components (the sum of the proportions if two or more types are included) is preferably 60 mol% or more, more preferably 75 mol% or more, and even more preferably 90 mol% or more, in order to obtain a film with excellent heat resistance.

[0046] Therefore, the semi-aromatic polyamide is preferably a compound having repeating units represented by the following formula (pa-1) in terms of excellent heat resistance, transparency, and thermal dimensional stability.

[0047] [ka]

[0048] In formula (pa-1), R represents a divalent hydrocarbon group containing an aromatic hydrocarbon ring.

[0049] Examples of the aromatic hydrocarbon ring include aromatic hydrocarbon rings having 6 to 12 carbon atoms, such as benzene rings and naphthalene rings.

[0050] The aromatic hydrocarbon ring may have substituents. Examples of substituents include halogen atoms, oxo groups, hydroxyl groups, and substituted oxy groups (e.g., C 1-4 Alkoxy groups, carboxyl groups, substituted oxycarbonyl groups (e.g., C 1-4 Examples include alkoxycarbonyl groups.

[0051] Examples of divalent hydrocarbon groups containing aromatic hydrocarbon rings include groups obtained by removing two hydrogen atoms from the structural formula of one aromatic hydrocarbon ring (for example, arylene groups having 6 to 12 carbon atoms, such as phenylene groups and naphthylene groups), groups obtained by removing two hydrogen atoms from a structural formula in which two or more aromatic hydrocarbon rings are bonded together by a single bond or a linking group, and groups in which the aforementioned group is bonded to a divalent aliphatic hydrocarbon group.

[0052] Examples of the aforementioned linking groups include divalent aliphatic hydrocarbon groups, carbonyl groups (-CO-), ether bonds (-O-), thioether bonds (-S-), and ester bonds (-COO-).

[0053] Examples of the divalent aliphatic hydrocarbon group include linear or branched alkylene groups having 1 to 5 carbon atoms, such as methylene, methylmethylene, dimethylmethylene, ethylene, propylene, and trimethylene.

[0054] Among the R groups, an arylene group having 6 to 12 carbon atoms is preferred, and a phenylene group is more preferred.

[0055] In formula (pa-1), n ​​represents an integer of 1 or more. n is preferably 6 to 12 in terms of excellent heat resistance, transparency, and thermal dimensional stability. The lower limit is preferably 7, particularly preferably 8, and most preferably 9. The upper limit is preferably 11, particularly preferably 10.

[0056] If n in equation (pa-1) is an integer greater than or equal to 2, then C in equation (pa-1) n H 2n The divalent saturated aliphatic hydrocarbon group represented by may be linear or branched.

[0057] Among the aforementioned semi-aromatic polyamides, compounds having repeating units represented by the following formula (pa-2) are preferred. In the following formula (pa-2), n is the same as described above.

[0058] [ka]

[0059] The semi-aromatic polyamide may have ring-opening polymerization of lactams such as ε-caprolactam, ζ-enanthractam, η-capryllactam, and ω-laurolactam, to the extent that it does not impair the effects of the present invention. That is, the semi-aromatic polyamide may have repeating units derived from the lactams in addition to the repeating units derived from the dicarboxylic acid component and the repeating units derived from the diamine component.

[0060] In the total number of constituent units constituting the semi-aromatic polyamide, the sum of the proportion of repeating units derived from the dicarboxylic acid component and the proportion of repeating units derived from the diamine component [preferably, the proportion of repeating units represented by the above formula (pa-1), more preferably the proportion of repeating units represented by the above formula (pa-2)] is preferably 60 mol% or more, more preferably 75 mol% or more, and even more preferably 90 mol% or more, in order to obtain a film with excellent heat resistance, transparency, and thermal dimensional stability.

[0061] As the aforementioned semi-aromatic polyamide, compounds having a melting point (Tm) of 270 to 350°C (preferably 300 to 330°C) and a glass transition temperature (Tg) of 120 to 180°C are preferred, as they offer excellent heat resistance and processability. The semi-aromatic polyamide's melting point (Tm) being within this range allows for efficient suppression of thermal decomposition during film processing. If the melting point (Tm) is below 270°C, the resulting film may have insufficient heat resistance. On the other hand, if the melting point (Tm) exceeds 350°C, thermal decomposition of the semi-aromatic polyamide may occur during film manufacturing.

[0062] Preferred examples of the aforementioned semi-aromatic polyamides include polyamide 6T (a reaction product of 1,6-hexanediamine and TPA, Tm: 320°C, Tg: 125°C), polyamide 9T (a reaction product of NDA and / or MODA and TPA, Tm: 302°C, Tg: 125°C), polyamide 10T (a reaction product of DDA and TPA, Tm: 316°C, Tg: 150°C), and polyamide 9N (a reaction product of NDA and / or MODA and naphthalenedicarboxylic acid).

[0063] The aforementioned semi-aromatic polyamide is preferably a compound containing a component derived from an aliphatic diamine having 9 to 12 carbon atoms, from the viewpoint of easy control of thermal shrinkage rate and light transmittance, and polyamide 9T is particularly preferred.

[0064] Furthermore, the intrinsic viscosity of the semi-aromatic polyamide is preferably 0.8 to 2.0 dL / g, and more preferably 0.9 to 1.8 dL / g, in that it allows for the production of films with excellent mechanical strength. The intrinsic viscosity of the semi-aromatic polyamide can be controlled by adjusting the degree of polymerization.

[0065] Semi-aromatic polyamides may contain polymerization catalysts and end-capping agents. Examples of polymerization catalysts include phosphoric acid, phosphorous acid, hypophosphorous acid, or salts thereof. Examples of end-capping agents include acetic acid, lauric acid, benzoic acid, octylamine, cyclohexylamine, and aniline.

[0066] Semi-aromatic polyamides can be produced using known methods such as methods A to D described below. Method A: A method of polymerization using acid chloride and diamine components as raw materials, by solution polymerization or interfacial polymerization. Method B: A method for producing a low-molecular-weight polymer using a dicarboxylic acid component and a diamine component as raw materials, and then increasing the molecular weight of the low-molecular-weight polymer by melt polymerization or solid-phase polymerization. Method C: A method of solid-phase polymerization in which a crushed mixture of salt and low polymer is produced using a dicarboxylic acid component and a diamine component as raw materials. Method D: A method of producing a salt using a dicarboxylic acid component and a diamine component as raw materials, and then solid-phase polymerizing it.

[0067] Of the aforementioned methods, methods C and D are preferred, with method D being more preferred. Compared to method B, methods C and D can produce the crushed mixture and salt to be subjected to solid-phase polymerization at low temperatures, and moreover, do not require a large amount of water when producing the crushed mixture and salt to be subjected to solid-phase polymerization. Therefore, the generation of gel-like material can be reduced, and the generation of fish eyes can be reduced.

[0068] Commercially available products can also be used as semi-aromatic polyamides. Examples of such commercially available products include "Genesta®" manufactured by Kuraray Co., Ltd., "Zecotto®" manufactured by Unitika Ltd., "Lenny®" manufactured by Mitsubishi Engineering Plastics Corporation, "Arlen®" manufactured by Mitsui Chemicals, Inc., and "Ultramid®" manufactured by BASF.

[0069] As the semi-aromatic polyamide, only virgin raw materials may be used, or off-spec film and cut-off trim (edge ​​trim) produced as by-products during film manufacturing may be recovered and mixed with the virgin raw materials. Examples of methods for mixing the raw materials include known methods such as the dry blending method and the melt mixing method, which uses a single-screw or twin-screw extruder to obtain the compound.

[0070] The aforementioned film may contain other resins in addition to semi-aromatic polyamide as a resin component, but from the viewpoint of thermal dimensional stability, the proportion of semi-aromatic polyamide is preferably 70% by mass or more of the total amount of resin components (100% by mass) contained in the film, more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 99% by mass or more.

[0071] (Additives) In addition to the resin components described above, the film may contain additives as needed, within a range that does not impair the effects of the present invention. Examples of such additives include lubricants, colorants (e.g., pigments and dyes such as titanium dioxide), color inhibitors, heat stabilizers, antioxidants (e.g., hindered phenols, phosphate esters, phosphite esters), weather resistance modifiers (e.g., benzotriazole compounds), flame retardants (e.g., halogenated flame retardants, phosphorus-based flame retardants), plasticizers, mold release agents, reinforcing agents (e.g., talc), modifiers, antistatic agents, ultraviolet absorbers, antifogging agents, and various polymer resins. These may be included individually or in combination of two or more.

[0072] Lubricants are components that reduce friction and improve slipperiness. Examples include inorganic particles such as silica, alumina, titanium dioxide, calcium carbonate, kaolin, and barium sulfate; and organic fine particles such as acrylic resin particles, melamine resin particles, silicone resin particles, and cross-linked polystyrene particles. The average particle size of the lubricant is, for example, 0.05 to 5.0 μm. The lower limit of the average particle size is preferably 0.1 μm, more preferably 0.5 μm, even more preferably 1.0 μm, and particularly preferably 2.0 μm. The upper limit of the average particle size is preferably 4.0 μm, more preferably 3.5 μm. The lubricant content is, for example, 0.3 parts by mass or less, preferably 0.05 to 0.3 parts by mass, per 100 parts by mass of semi-aromatic polyamide. The average particle size and content of the lubricant can be appropriately adjusted according to the required characteristics of the film, such as friction characteristics and optical properties.

[0073] The additive content (total content if two or more types are included) is, for example, 5 parts by mass or less, preferably 3 parts by mass or less, and more preferably 1 part by mass or less, per 100 parts by mass of semi-aromatic polyamide. The lower limit of the content is, for example, 0.05 parts by mass.

[0074] The above-mentioned additive can be incorporated into the film, for example, by the following method. (i) Method of adding additives during polymerization of semi-aromatic polyamides (ii) A method in which a pellet (masterbatch) is prepared by melt-kneading a high concentration of additives and semi-aromatic polyamide, and the masterbatch and natural pellets (additive-free semi-aromatic polyamide pellets) are melt-kneaded in an extruder during film formation (masterbatch method). (iii) A method of forming a film by loading a dry blend of semi-aromatic polyamide and additives into an extruder, melting and kneading the mixture in the extruder, and forming a film. (iv) A method of forming a film by charging a semi-aromatic polyamide and an additive into an extruder, melting and kneading them in the extruder, and then forming the film.

[0075] [Film manufacturing method] The film is preferably a biaxially oriented film. The film can be manufactured, for example, by using the above-mentioned resin component and additives as necessary as raw materials, forming an unstretched film by extruding the raw materials (film formation), and then subjecting the unstretched film to stretching and relaxation treatments.

[0076] Alternatively, a heat-setting treatment may be performed after the stretching treatment, followed by a relaxation treatment.

[0077] (film formation) The film formation process involves using the above-mentioned resin components and additives added as needed as raw materials, and forming an unstretched film by extruding the raw materials.

[0078] Unstretched film can be manufactured, for example, by introducing the raw materials into an extruder, melting and mixing them at a temperature of 280 to 340°C for 3 to 15 minutes, extruding them into a film through a T-die, and then cooling the extruded film by bringing it into close contact with a cooling roll. The temperature of the cooling roll is preferably 30 to 40°C, as this suppresses the crystallization of the semi-aromatic polyamide, resulting in an unstretched film that is easy to stretch and can be stretched to a uniform thickness.

[0079] The thickness of the unstretched film is, for example, 100 to 800 μm.

[0080] The crystallization heat of the unstretched film is preferably 20 J / g or more (for example, 20-30 J / g), and more preferably 25 J / g or more. If the crystallization heat of the unstretched film is less than 20 J / g, crystallization is progressing, and the biaxially oriented film obtained by biaxially stretching this unstretched film will have a low tensile elongation at break, and if it contains a lubricant such as silica, the haze tends to be high. In addition, stretching may be unstable, and stretching may become impossible due to frequent breakage, and a higher stretching force is required in the initial stages of stretching, making it difficult to obtain a biaxially oriented film of uniform thickness.

[0081] (Stretching process) The stretching process involves stretching the unstretched film obtained in the previous step in two directions, the MD direction (longitudinal direction) and the TD direction (width direction), to obtain a biaxially oriented film. When the unstretched film is subjected to the stretching process, the semi-aromatic polyamide contained in the unstretched film becomes oriented and crystallizes.

[0082] Biaxial stretching processes include simultaneous biaxial stretching and sequential biaxial stretching. Furthermore, biaxial stretching methods include the flat method (flat sequential biaxial stretching method, flat simultaneous biaxial stretching method) and the tubular method. Among these, the flat method is preferred because it yields biaxially oriented films with good thickness accuracy.

[0083] Examples of stretching devices for performing biaxial stretching using the flat-type sequential biaxial stretching method include roll stretching devices and tenter devices. Examples of stretching devices for performing biaxial stretching using the flat-type simultaneous biaxial stretching method include screw tenters, pantograph tenters, and linear motor-driven clip tenters.

[0084] Stretch ratio in the MD direction (E MD The stretch ratio (E) is, for example, 2 to 3.5 times. MD The lower limit of the stretch ratio (E) is preferably 2.3 times, and more preferably 2.5 times. MD The upper limit of ) is preferably 3 times, and more preferably 2.8 times.

[0085] Elongation ratio in the TD direction (E TD The ratio of elongation (E) is, for example, 2 to 4 times. TD The lower limit of the stretch ratio (E) is preferably 2.5 times, more preferably 3 times, and even more preferably 3.2 times. TD The upper limit of ) is preferably 3.8 times, and more preferably 3.6 times.

[0086] Stretch ratio in the MD direction (E MD ) and the stretching ratio in the TD direction (E TD ) preferably satisfies the following formula (1). 1.0 ≤ E TD / E MD ≤1.5 (1)

[0087] E TD / E MD The lower limit is preferably 1.1, more preferably 1.2, and even more preferably 1.25. E TD / E MD The upper limit is preferably 1.4, more preferably 1.35.

[0088] Stretch ratio in the MD direction (E MD ) and the stretching ratio in the TD direction (E TD It is particularly preferable that ) satisfies the following equation (1-1). 1.25 <E TD / E MD <1.35 (1-1)

[0089] In the case of sequential biaxial stretching, the stretching ratio in the MD direction (E MD If the value exceeds the aforementioned range, the resulting biaxially oriented film tends to undergo excessive crystallization, resulting in reduced stretchability in the TD direction. Furthermore, even if stretching in the TD direction is possible, the resulting biaxially oriented film may exhibit reduced tensile elongation at break in the MD direction, leading to decreased transparency.

[0090] In the case of simultaneous biaxial stretching, the stretching ratio (E) in the MD direction MD If the value exceeds the aforementioned range, the resulting stretched film tends to have a high thermal shrinkage rate and reduced dimensional stability. On the other hand, the stretching ratio in the TD direction (E TD If the value exceeds the aforementioned range, the resulting stretched film tends to have a high thermal shrinkage rate, reduced dimensional stability, and a further decrease in tensile elongation at break. Also, the stretching ratio in the MD direction (E MD ) and the stretching ratio in the TD direction (E TD If the value falls below the aforementioned range, the resulting stretched film is prone to stretching unevenness, and the flatness tends to decrease due to the occurrence of thickness unevenness.

[0091] The stretching speed is not particularly limited, but in order to avoid tearing of the film, it is preferable that the stretching strain speed in the MD direction and the TD direction be 400 to 12000% / min, respectively.

[0092] The stretching temperature is preferably above the Tg of the semi-aromatic polyamide, more preferably above Tg and below (Tg + 50°C), and even more preferably above Tg and below (Tg + 30°C). If the stretching temperature falls below the above range, the film tends to break easily, making stable production difficult. If the stretching temperature exceeds the above range, stretching unevenness tends to occur in the film, and the flatness tends to decrease.

[0093] (heat fixation) The heat-setting process involves heat-treating the biaxially oriented film obtained in the previous process while holding the film with the clips used during stretching. By subjecting the biaxially oriented film obtained in the previous process to this process, the occurrence of heat-induced unevenness is suppressed, and the effect of reducing the thermal shrinkage rate is obtained.

[0094] The heat-fixing temperature is, for example, 260 to 285°C, more preferably 265 to 280°C, and even more preferably 270 to 280°C.

[0095] Furthermore, thermal setting may be performed by maintaining a constant temperature or by creating a temperature gradient. In the present invention, it is preferable to perform thermal setting with a temperature gradient, in particular, from the viewpoint of improving the effect of reducing the thermal shrinkage rate. It is even more preferable to divide the process into a first half and a second half, and set the temperature of the second half to be slightly higher than that of the first half (for example, setting the first half to a range of 260°C to 270°C, and the second half to a range of over 270°C to 280°C).

[0096] Furthermore, the heat-setting time (total time if divided into a first and second half) is, for example, 1 to 50 seconds, more preferably 5 to 40 seconds, and even more preferably 8 to 30 seconds. If the heat-setting time falls below the above range, the heat-setting will be insufficient. Conversely, if the heat-setting time exceeds the above range, the crystallization of the semi-aromatic polyamide may be excessively promoted, making it difficult to achieve the dimensional stability specified in the present invention.

[0097] The heat treatment in this process can be carried out by known and conventional methods such as blowing hot air, irradiating with infrared rays, or irradiating with microwaves. In this invention, the method of blowing hot air is preferred because it can heat uniformly and accurately.

[0098] (Relaxation treatment) The relaxation process involves relaxing a biaxially oriented film that has undergone a heat-setting process under predetermined temperature conditions, for a predetermined time, and at a predetermined relaxation rate. By subjecting the biaxially oriented film to this process, residual stress in the film can be removed, thereby improving its thermal dimensional stability.

[0099] The slackening of a biaxially oriented film can be achieved, for example, by slowing down the take-up speed of a biaxially oriented film that is continuously run in a suspended state. Furthermore, when the stretching process is performed using simultaneous biaxial stretching or sequential biaxial stretching, the slackening process can be performed simultaneously in-line in both the MD and TD directions.

[0100] The relaxation of a biaxially oriented film can also be performed by first relaxing the biaxially oriented film in the TD direction, then winding it up, and passing it offline through a drying oven set to a predetermined temperature under low tension, thereby relaxing it in the MD direction.

[0101] It is preferable that the relaxation treatment temperature be the same as the temperature at which heat fixing is performed (the same temperature as the heat fixing temperature if heat fixing is performed at a constant temperature, or the final heat fixing temperature in the heat fixing process if heat fixing is performed with a temperature gradient).

[0102] The relaxation treatment time is, for example, 5 to 30 seconds, preferably 5 to 15 seconds.

[0103] Relaxation rate in the MD direction (R MD The relaxation rate (R) is, for example, 2-8%. MD The lower limit of the relaxation rate (R) is preferably 2.5%, more preferably 2.8%, and even more preferably 3%. MD The upper limit of ) is preferably 7%, and more preferably 6%.

[0104] Relaxation rate in the TD direction (R TD The relaxation rate (R) is, for example, 1.5-6%. TD The lower limit of ) is preferably 2%. Relaxation rate (R TD The upper limit of ) is preferably 5.5%, more preferably 5%, and even more preferably 4%.

[0105] Relaxation rate in the MD direction (R MD ) and the stretching ratio in the MD direction (E MD It is preferable that the following formula (2) is satisfied, as this provides excellent thermal dimensional stability. 1.1 ≤ R MD / E MD ≤2.3 (2)

[0106] R MD / E MD The lower limit is preferably 1.15. R MD / E MD The upper limit is preferably 2.0, more preferably 1.5.

[0107] Relaxation rate in the TD direction (R TD ) and the stretching ratio in the TD direction (E TD It is preferable that the following formula (3) is satisfied, as this provides excellent thermal dimensional stability. 0.5 ≤ R TD / E TD ≤1.3 (3)

[0108] R TD / E TD The lower limit is preferably 1.0, more preferably 0.8. R TD / E TD The upper limit is preferably 1.1, more preferably 0.9.

[0109] When the relaxation treatment is performed at the aforementioned relaxation rate, the thermal shrinkage rate and moisture elongation rate are reduced, and a biaxially oriented film with excellent thermal dimensional stability is obtained.

[0110] In the apparatus for manufacturing the aforementioned film, it is preferable that the surfaces of the cylinder, barrel melting section, metering section, single pipe, filter, T-die, etc., are treated to reduce surface roughness in order to prevent the accumulation of raw materials. Methods for reducing surface roughness include, for example, modifying the surface with a low-polarity substance or depositing silicon nitride or diamond-like carbon onto the surface.

[0111] The film produced by the above method may be in the form of a single sheet or may be wound onto a winding roll to form a film roll. From the viewpoint of productivity when used for various applications, it is preferable to use it in the form of a film roll. The film in the form of a film roll may be slit to a desired width.

[0112] Furthermore, the film may be a single-layer film consisting of one type of layer, or a multilayer film consisting of two or more layers laminated together. If the film has a multilayer structure, the surface roughness of the film can be easily controlled and the adhesion to the crystalline transparent conductive film can be improved by incorporating a lubricant, of a selected type and amount, into the surface layer of the multilayer structure (for example, one of the two layers in a two-layer film, or one of the surface layers or both surface layers in a three-layer film).

[0113] Furthermore, the surface of the film may be subjected to surface treatments such as corona treatment, plasma treatment, acid treatment, or flame treatment in order to improve adhesion with other materials.

[0114] Furthermore, the film may have one or more layers laminated onto it, selected from inorganic materials such as metals or metal oxides, other polymers, paper, woven fabrics, nonwoven fabrics, wood, hard coat layers, and the like.

[0115] [Transparent conductive laminate] The transparent conductive laminate of the present invention has a laminated structure of the above-mentioned film and a crystalline transparent conductive film. In addition to the laminated structure of the above-mentioned film and crystalline transparent conductive film, the transparent conductive laminate may also have one or more other layers.

[0116] The overall thickness of the transparent conductive laminate is preferably, for example, 10 μm or more, more preferably 20 μm or more, and even more preferably 25 μm or more. Furthermore, the thickness is preferably, for example, 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, and particularly preferably 40 μm or less.

[0117] Examples of transparent conductive materials constituting a crystalline transparent conductive film include ITO (indium tin oxide), FTO (fluorine-doped indium oxide), ZnO (zinc oxide), AZO (aluminum-doped zinc oxide), gallium-doped zinc oxide (GZO), tin oxide (SnO2), indium oxide (In2O3), tungsten oxide (WO3); conductive polymers such as polyethylenedioxythiophene (PEDOT); silver nanowires, carbon nanotubes (CNTs), etc. In the present invention, ITO is preferred in terms of its excellent transparency and conductivity.

[0118] The thickness of the crystalline transparent conductive film is, for example, 1 to 500 nm.

[0119] The transparent conductive laminate of the present invention can be manufactured, for example, through the following vapor deposition and heat treatment processes. Vapor deposition process: A transparent conductive material is vapor-deposited onto the (biaxially oriented) film produced by the above film manufacturing method to obtain a vapor-deposited laminated film having a structure in which a vapor-deposited film is laminated on the film. Heat treatment process: The vapor-deposited film laminate is heat-treated at a temperature of 100°C or higher to obtain a transparent conductive laminate having a laminated structure of the (biaxially oriented) film and a crystalline transparent conductive film.

[0120] The (biaxially oriented) film contains a semi-aromatic polyamide as a resin component and has the following heat shrinkage rate and total light transmittance. Thermal shrinkage rate: After heat treatment at 200°C for 15 minutes, the thermal shrinkage rates in the MD direction and TD direction are -0.20% to 0.20%, respectively. Total light transmittance: The total light transmittance measured according to JIS K7136 after heat treatment at 200°C for 15 minutes must be 85.0% or higher.

[0121] (vapor deposition process) The vapor deposition process involves depositing a transparent conductive material onto the (biaxially oriented) film, for example by sputtering, to produce a vapor-deposited laminated film having a structure in which a vapor-deposited film of the transparent conductive material is laminated onto the (biaxially oriented) film. The transparent conductive material contained in the vapor-deposited film is amorphous or low-crystalline.

[0122] (Heat treatment process) The heat treatment step is a process to improve the crystallinity of the amorphous or low-crystallinity transparent conductive material contained in the deposited film of the deposited film laminate obtained in the deposition step, thereby enhancing the transparency and conductivity of the deposited film. Through this step, a transparent conductive laminate having a laminated structure of the above (biaxially oriented) film and a crystalline transparent conductive film is obtained.

[0123] The heat treatment temperature is 100°C or higher, and from the viewpoint of accelerating the crystallization rate, it is preferably 150°C or higher (for example, 150-250°C), more preferably 180°C or higher, and even more preferably 200°C or higher.

[0124] The heat treatment time is preferably 10 seconds or more, more preferably 30 seconds or more, and more preferably 45 seconds or more, from the viewpoint of increasing crystallinity and improving conductivity. Furthermore, from the viewpoint of reducing working time, the heat treatment time is preferably 60 minutes or less, more preferably 30 minutes or less, and even more preferably 15 minutes or less. When the heat treatment temperature is set higher within the above temperature range, the heat treatment time can be set shorter within the above range. On the other hand, when the heat treatment temperature is set lower within the above temperature range, it is preferable to set the heat treatment time longer within the above range.

[0125] According to the above manufacturing method, since the above (biaxially oriented) film is used as a support, even if the amorphous transparent conductive film is heat-treated at a high heat treatment temperature, haze rise, shrinkage, deformation, etc., do not occur in the support. Therefore, a crystalline transparent conductive film with high crystallinity and excellent transparency and conductivity can be manufactured efficiently without cracking.

[0126] Therefore, the transparent conductive laminate obtained by the above manufacturing method has high transparency and excellent conductivity, and can be suitably used as a transparent electrode, transparent conductive layer, transparent substrate, biosensor, etc., for electronic devices and optical devices.

[0127] [device] The device of the present invention comprises the transparent conductive laminate described above.

[0128] Examples of the aforementioned devices include display devices such as liquid crystal displays and organic EL displays; input devices such as touch panels; lighting devices such as LEDs and organic ELs; and electronic and optical devices such as perovskite solar cells, electromagnetic shielding materials, antistatic films, medical electrodes and sensors, circuit boards, heaters, and antennas.

[0129] The configurations and combinations thereof described above are merely examples, and additions, omissions, substitutions, and modifications to the configurations are permitted as appropriate, without departing from the spirit of the present invention. Furthermore, the present invention is not limited by its embodiments. [Examples]

[0130] The present invention will be described more specifically below with reference to examples, but the present invention is not limited to these examples.

[0131] Manufacturing Example 1 (Manufacturing of semi-aromatic polyamide pellets) 3289 parts by mass of terephthalic acid (TPA), 2533 parts by mass of 1,9-nonanediamine (NDA), 633 parts by mass of 2-methyl-1,8-octanediamine (MODA), 48.9 parts by mass of benzoic acid (BA), 6.5 parts by mass of sodium hypophosphate monohydrate (corresponding to 0.1% by mass of the total of TPA, NDA, MODA, and BA), and 2200 parts by mass of distilled water were placed in a reaction vessel and purged with nitrogen. The molar ratio of these raw materials (TPA / BA / NDA / MODA) was 99 / 2 / 80 / 20.

[0132] The contents of the reaction vessel were stirred at 100°C for 30 minutes, and then the internal temperature was raised to 210°C over 2 hours. At this time, the internal pressure of the reaction vessel was raised to 2.12 MPa. The reaction continued for 1 hour, then the temperature was raised to 230°C and maintained at that temperature for 2 hours, after which the steam was gradually released, and the reaction continued while maintaining the pressure at 2.12 MPa. Next, the pressure was reduced to 0.98 MPa over 30 minutes, and the reaction was continued for another hour to obtain a prepolymer. The obtained prepolymer was dried under reduced pressure at 100°C for 12 hours, and then pulverized to a size of 2 mm or less. Next, the pulverized prepolymer was solid-phase polymerized at a temperature of 230°C and a pressure of 13.3 Pa for 10 hours to obtain the semi-aromatic polyamide polymer "PA9T". The obtained polymer was fed into a twin-screw extruder, melt-kneaded and extruded under conditions of a cylinder temperature of 320°C, then cooled and cut to produce polymer pellets (natural pellets). The polymer "PA9T" had an intrinsic viscosity of 1.17 dL / g, a melting point of 290°C, and a glass transition temperature of 125°C.

[0133] The intrinsic viscosity of the polymer was measured using the following method. The intrinsic viscosity (η) of the polymer at concentrations of 0.05 g / dL, 0.1 g / dL, 0.2 g / dL, and 0.4 g / dL in concentrated sulfuric acid at 30°C. inh The intrinsic viscosity (η) obtained is calculated from the following formula. inh The intrinsic viscosity [η] was defined as the value obtained by extrapolating the value such that the polymer concentration becomes zero. η inh =[ln(t1 / t0)] / c (In the formula, η inh (where is the intrinsic viscosity (dL / g), t0 is the solvent flow time (seconds), t1 is the polymer solution flow time (seconds), and c is the polymer concentration in the polymer solution (g / dL).)

[0134] Manufacturing Example 2 (Manufacturing of Silica-Containing Masterbatch) A masterbatch (M1) containing 2% by mass of silica was prepared by melt-kneading 98 parts by mass of semi-aromatic polyamide pellets obtained by the same method as in Production Example 1 with 2 parts by mass of silica (Silohobic 100, manufactured by Fuji Silysia Chemical Co., Ltd., average particle size 2.7 μm).

[0135] Example 1 (Manufacturing of a biaxially oriented film and a transparent conductive laminate containing the film) (film formation) A mixture was obtained by mixing 100 parts by mass of semi-aromatic polyamide pellets obtained in Production Example 1 with a masterbatch (M1) containing 0.2 parts by mass of a heat-resistant stabilizer (Sumirizer GA-80, manufactured by Sumitomo Chemical Co., Ltd.) and 0.1 parts by mass of silica.

[0136] The resulting mixture was melted in a 65 mm single-screw extruder with cylinder temperatures set to 295°C (initial stage), 320°C (middle stage), and 320°C (final stage). It was then extruded into a film through a T-die set to 320°C, electrostatically adhered to a cooling roll set to a surface temperature of 40°C, and cooled to obtain a substantially unoriented, unstretched PA film with a thickness of 205 μm (crystallization heat: 26 J / g).

[0137] (Stretching process) Next, the obtained unstretched PA film was biaxially stretched using a flat-type sequential stretcher. First, an unstretched PA film was heated to 130°C by roll heating and infrared heating, and then stretched in the MD direction at a stretching ratio of 2.55 times to obtain a longitudinally stretched PA film. Next, the longitudinally oriented PA film was guided to a transverse stretching machine (preheating temperature: 110°C, stretching temperature: 148°C) while both ends were held with clips, and stretched in the TD direction at a stretching ratio of 3.4 times. This resulted in a biaxially oriented PA film.

[0138] (heat fixation) The biaxially oriented PA film, while held by clips, was subjected to a heat-setting treatment at 270°C for 5 seconds in a heat-setting zone, and immediately thereafter, another heat-setting treatment at 275°C for 5 seconds.

[0139] (Relaxation treatment) Under a temperature atmosphere of 275°C, a relaxation treatment was performed by adjusting the distance between clips to achieve a 3% relaxation in the MD direction and a 2% relaxation in the TD direction. This resulted in a biaxially oriented PA film with a thickness of 27 μm.

[0140] (Vapor deposition) A biaxially oriented PA film obtained after a relaxation treatment was coated with ITO by sputtering to obtain a vapor-deposited laminated film having a laminated structure of the biaxially oriented PA film and an amorphous ITO film.

[0141] (Heat treatment) The obtained vapor-deposited laminated film was heat-treated at 150°C for 30 minutes, and then further heat-treated at 200°C for 15 minutes to convert the amorphous ITO film contained in the vapor-deposited film into a crystalline ITO film, thereby obtaining a transparent conductive laminate which is a laminate of the biaxially oriented PA film and the crystalline ITO film.

[0142] Example 2 A biaxially oriented PA film was obtained in the same manner as in Example 1, except that the thickness of the biaxially oriented PA film was changed to match the table below, and a transparent conductive laminate was obtained.

[0143] Example 3 A biaxially oriented PA film was obtained in the same manner as in Example 1, except that the thickness of the biaxially oriented PA film was changed to match the table below, and a transparent conductive laminate was obtained.

[0144] Example 4 A biaxially oriented PA film was obtained in the same manner as in Example 1, except that the stretching ratio and relaxation rate were changed as shown in the table below, and a transparent conductive laminate was obtained.

[0145] Example 5 A biaxially oriented PA film was obtained in the same manner as in Example 1, except that the stretching ratio and relaxation rate were changed as shown in the table below, and a transparent conductive laminate was obtained.

[0146] Example 6 A biaxially oriented PA film was obtained in the same manner as in Example 1, except that the stretching ratio and relaxation rate were changed as shown in the table below, and a transparent conductive laminate was obtained.

[0147] Comparative Example 1 A biaxially oriented PA film was obtained in the same manner as in Example 1, except that a relaxation treatment in the MD direction was not performed, and a transparent conductive laminate was obtained.

[0148] Comparative Example 2 A biaxially oriented PA film was obtained in the same manner as in Example 1, except that a relaxation treatment in the TD direction was not performed, and a transparent conductive laminate was obtained.

[0149] Comparative Example 3 A transparent conductive laminate was obtained in the same manner as in Example 1, except that a polyethylene terephthalate (PET) film (SLS-50, manufactured by Unitika Ltd., 50 μm thick) was used instead of a biaxially oriented PA film.

[0150] Comparative Example 4 A transparent conductive laminate was obtained in the same manner as in Example 1, except that a polyethylene naphthalate (PEN) film (Q53-50, manufactured by Toyobo Co., Ltd., 50 μm thick) was used instead of a biaxially oriented PA film.

[0151] (evaluation) The films and transparent conductive laminates of the examples and comparative examples were evaluated using the following method.

[0152] (1) Film thickness Using a digital display meter (HEIDENHAIN, model ND287), we took measurements at 10 or more points and calculated the average value.

[0153] (2) Thermal shrinkage rate of the film A test specimen (100 mm in the MD direction x 10 mm in the TD direction) was cut from the film. The obtained test specimen was heat-treated at 150°C for 30 minutes or 200°C for 15 minutes, and then left for 2 hours in an atmosphere of 23°C and 50% RH humidity. Subsequently, the dimensions of each heat-treated specimen were measured in the MD and TD directions, and the thermal shrinkage rate S in the MD direction was calculated using the following formula. MD and thermal shrinkage coefficient S in the TD direction TD The result was calculated. Thermal shrinkage rate (%) = [{Dimensions before test - Dimensions after test} / Dimensions before test] × 100 The above test was repeated three times, and the average value obtained was defined as the thermal shrinkage rate of the film.

[0154] (3) Film haze, total light transmittance Test specimens (100 mm in the MD direction x 50 mm in the TD direction) were cut from the film after heat treatment at 200°C for 15 minutes. The obtained test specimens were mounted on a jig, and the haze and total light transmittance were measured in accordance with JIS K7136 using a haze meter (NDH4000 model, manufactured by Nippon Denshoku Industries Co., Ltd.).

[0155] (4) Crack resistance of transparent conductive laminates After heat treatment at 150°C for 30 minutes or 200°C for 15 minutes, the transparent conductive laminate was visually inspected to check for cracks, and its crack resistance was evaluated according to the following criteria. Good (〇): No cracks occurred. Defective (×): Cracks occurred.

[0156] The results are summarized in the table below.

[0157] [Table 1]

[0158] In Examples 1-6, a biaxially oriented PA film subjected to specific stretching and relaxation treatments was used as a support. The biaxially oriented PA film possesses excellent thermal dimensional stability and transparency. Therefore, high-temperature heat treatment could be performed on the ITO film after deposition while suppressing haze rise and thermal shrinkage of the biaxially oriented PA film, thereby increasing the crystallinity of the ITO film. As a result, a transparent conductive laminate with excellent transparency and conductivity was obtained without crack formation. Furthermore, the biaxially oriented PA film exhibits excellent thermal dimensional stability and transparency not only with heat treatment at 150°C for 30 minutes, but also with heat treatment at 200°C for 15 minutes. Therefore, by using the biaxially oriented PA film as a support, a transparent conductive laminate with excellent transparency and conductivity can be quickly formed without crack formation by heat treatment at higher temperatures and for shorter periods, resulting in superior work efficiency.

[0159] On the other hand, in the transparent conductive laminates of Comparative Examples 1 and 2, a biaxially oriented PA film that had not undergone relaxation treatment in the MD or TD direction was used as the support. The biaxially oriented PA film has a large thermal shrinkage rate during heat treatment. As a result, cracks occurred in the ITO film regardless of whether heat treatment was performed at 150°C for 30 minutes or 200°C for 15 minutes.

[0160] In Comparative Example 3, a PET film was used as the support. PET films have poor thermal dimensional stability; while they can maintain transparency after heat treatment, they exhibit a high thermal shrinkage rate. As a result, cracks occurred in the ITO film regardless of whether heat treatment was performed at 150°C for 30 minutes or 200°C for 15 minutes.

[0161] In Comparative Example 4, a PEN film was used as the support. The PEN film has a certain degree of thermal dimensional stability. Therefore, when heat treatment was performed at 150°C for 30 minutes, thermal shrinkage was suppressed, and no cracks occurred in the ITO film. However, when heat treatment was performed at 200°C for 15 minutes, thermal shrinkage occurred, and cracks occurred in the ITO film. Furthermore, the haze value of the PEN film increased significantly after heat treatment, and its transparency decreased considerably.

Claims

1. A film used as a support when forming a crystalline transparent conductive film by depositing a transparent conductive material and heat-treating it at a temperature of 200°C or higher, The resin component contains a semi-aromatic polyamide. A film having a thermal shrinkage rate of -0.20% to 0.20% in the MD and TD directions, respectively, after heat treatment at 200°C for 15 minutes, and a total light transmittance of 85.0% or more, as measured in accordance with JIS K7136.

2. The film according to claim 1, wherein the haze value per 1 μm of film thickness, measured in accordance with JIS K7136 after heat treatment at 200°C for 15 minutes, is 0.20% or less.

3. The film according to claim 1 or 2, wherein the semi-aromatic polyamide is a compound having repeating units represented by the following formula (pa-1). 【Chemistry 1】 (In the formula, R represents a divalent hydrocarbon group containing an aromatic hydrocarbon ring, and n represents an integer from 6 to 12.)

4. The film according to claim 1 or 2, wherein the semi-aromatic polyamide is polyamide 9T.

5. A transparent conductive laminate having a laminated structure of the film described in claim 1 or 2 and a crystalline transparent conductive film.

6. The transparent conductive laminate according to claim 5, wherein the crystalline transparent conductive film is a crystalline ITO film.

7. A device comprising the transparent conductive laminate described in claim 5.

8. After undergoing the stretching and relaxation processes described below, and heat-treating at 200°C for 15 minutes, a film is produced in which the thermal shrinkage rates in the MD and TD directions are -0.20% to 0.20%, respectively, and the total light transmittance measured in accordance with JIS K7136 is 85.0% or higher. A method for manufacturing a transparent conductive laminate, comprising: laminating a vapor-deposited film of a transparent conductive material onto a generated film; and heat-treating the film with the vapor-deposited film laminated on it at a temperature of 100°C or higher to obtain a transparent conductive laminate having a laminated structure of the film and a crystalline transparent conductive film. Stretching process: An unstretched film containing semi-aromatic polyamide as a resin component is stretched in the MD direction at a stretch ratio (E ＭＤ ) Stretching process of 2 to 3.5 times, and stretching ratio (E) in the TD direction ＴＤ ) Apply a stretching treatment to increase the material's length by 2 to 4 times. Relaxation process: After the stretching process, the film is subjected to a relaxation process in the MD direction (R ＭＤ ) Relaxation treatment of 2-8%, and relaxation rate (R) in the TD direction ＴＤ ) Apply a relaxation treatment of 1.5-6%.

9. The stretching ratio (E) in the MD direction. ＭＤ ), stretching ratio in the TD direction (E ＴＤ ), relaxation rate in the MD direction (R ＭＤ ), and the relaxation rate in the TD direction (R ＴＤ A method for manufacturing a transparent conductive laminate according to claim 8, wherein the following formulas (1) to (3) are satisfied. 1.0≦E ＴＤ / E ＭＤ ≦1.5 (1) 1.1 ≦ R ＭＤ / E ＭＤ ≦2.3 (2) 0.5 ≦R ＴＤ / E ＴＤ ≦1.3 (3)

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