JP7135695B2 - Method for producing conductive film with protective film - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a conductive film with a protective film.

BACKGROUND ART Conventionally, conductive films have been widely used in touch panels and the like. The conductive film includes a light-transmitting substrate and a conductive portion provided on one side of the light-transmitting substrate. The conductive portion of the conductive film mainly contains indium tin oxide (ITO ) is used.

However, since ITO does not have flexibility, when a flexible base material is used as the light-transmissive base material, there is a problem that cracks are likely to occur in the conductive portion.

For this reason, currently, instead of ITO, metal nanowires such as silver nanowires are used to form conductive portions (see, for example, Patent Document 1).

JP 2015-68674 A

However, when a conductive portion is formed using metal nanowires, crack-like streak unevenness may appear in the conductive portion. In this specification, "crack-like streak unevenness" means streak unevenness that looks like cracks, and does not mean that cracks are occurring. In addition, in the conductive film using metal nanowires, it is currently required to suppress sticking between the films when the film is wound.

The present invention has been made to solve the above problems. That is, it is an object of the present invention to provide a method for producing a conductive film with a protective film that can suppress crack-like streak unevenness and can suppress sticking between films when wound.

The present invention includes the following inventions.
[1] A step of forming a resin layer on the first surface side of a light-transmitting substrate; A method for producing a conductive film with a protective film, comprising: directly forming a conductive portion containing conductive fibers on a surface; and detachably attaching a protective film to the surface of the conductive portion.

[2] The manufacturing method according to [1] above, further comprising the step of removing static electricity from the light-transmissive substrate before forming the conductive portion.

[3] The production method according to [2] above, wherein the light-transmitting substrate is destaticized before the resin layer is formed.

[4] The manufacturing method according to any one of [1] to [3] above, wherein the light-transmitting substrate has a base layer only on one side.

[5] The light-transmitting base material includes a base material body and an underlying layer provided on one surface of the base material body, the surface of the underlying layer forming the first surface, and The manufacturing method according to any one of [1] to [4] above, wherein the conductive portion is adjacent to the base body.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the electrically conductive film with a protective film which can suppress the crack-like streak unevenness of an electrically-conductive part, and can suppress sticking of films when wound up can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the conductive film with a protective film which concerns on embodiment. FIG. 2 is an enlarged view of a part of the conductive film with a protective film shown in FIG. 1; It is the figure which showed typically the mode of a continuous folding test. It is the figure which showed typically the manufacturing process of the conductive film with a protective film which concerns on embodiment. It is the figure which showed typically the manufacturing process of the conductive film with a protective film which concerns on embodiment. It is the figure which showed typically the manufacturing process of the conductive film with a protective film which concerns on embodiment.

Hereinafter, a conductive film with a protective film and a method for producing the same according to embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a conductive film with a protective film according to the present embodiment, FIG. 2 is an enlarged view of a part of the conductive film with a protective film shown in FIG. 1, and FIG. 3 is a continuous folding test. It is a diagram schematically showing the state of. 4 to 6 are diagrams schematically showing manufacturing steps of a conductive film with a protective film according to this embodiment.

<<<Conductive film with protective film>>>
A conductive film 10 with a protective film shown in FIG. 1 includes a conductive film 20 and a protective film 30 detachably attached to a surface 20A of the conductive film 20 .

<<Conductive film>>
The conductive film 20 includes a light-transmitting substrate 21, a resin layer 22 provided on the first surface 21A side of the light-transmitting substrate 21, and the first surface 21A of the light-transmitting substrate 21. and a conductive portion 23 provided directly on the second surface 21B on the opposite side. As used herein, the term "optical transparency" means the property of transmitting light. Also, the term “light transmissive” does not necessarily mean transparent, and may be translucent. The conductive portion 23 is in a layered state before being patterned. As used herein, the term “conductive portion” means a portion that is electrically conductive from the surface, and is a concept that includes both layered forms and non-layered forms. The conductive film 20 does not have a conductive portion on the resin layer 22 side, but may have a conductive portion.

The surface 20A of the conductive film 20 is composed of the surface 23A of the conductive portion 23, and the back surface 20B of the conductive film 20 is composed of the surface 22A of the resin layer 22. As shown in FIG. The properties, physical values, and the like of the conductive film 20 will be described below. The properties, physical values, and the like of the conductive film 20 are the properties and physical values of the conductive film 20 alone after the protective film 30 has been peeled off. .

The conductive film 20 preferably has flexibility. When the conductive film 20 has flexibility, the resin layer 22 is inside (the conductive portion 23 is outside) with respect to the conductive film 20, and the distance between the opposing sides of the conductive film 20 is 4 mm. Even when a continuous folding test is performed in which the conductive film 20 is repeatedly folded 180° 100,000 times so that the . When the continuous folding test is performed on the conductive film, if the electrical resistance value ratio of the conductive portion of the conductive film before and after the continuous folding test exceeds 3, there is a possibility that the conductive film may crack. Therefore, the flexibility of the conductive film becomes insufficient. Here, if cracks or the like occur in the conductive film due to the continuous folding test, the conductivity will decrease. The electrical resistance is higher than the electrical resistance of the conductive portion of the film. Therefore, by obtaining the electrical resistance value of the conductive portion of the conductive film before and after the continuous folding test, it is possible to determine whether or not the conductive film is cracked or the like.

Even if the number of times of folding in the continuous folding test is 200,000, it is more preferable that the electrical resistance value ratio of the conductive portion 23 of the conductive film 20 before and after the continuous folding test is 3 or less. Further, even if the number of times of folding in the continuous folding test is one million times, it is more preferable that the electrical resistance value ratio of the conductive portion 23 of the conductive film 20 before and after the continuous folding test is 3 or less.

Regardless of whether the number of times of folding in the continuous folding test is 100,000, 200,000, or 1,000,000, the electrical resistance value ratio of the conductive portion 23 of the conductive film 20 before and after the continuous folding test is 1, respectively. 0.5 or less is more preferable.

In the continuous folding test, the conductive film 20 is folded so that the resin layer 22 is on the inside (the conductive portion 23 is on the outside), but the conductive film 20 is folded so that the conductive portion 23 is on the inside (the resin layer 22 is on the outside). The film 20 may be folded. Even in this case, it is preferable that the electric resistance value ratio of the conductive portion 23 of the conductive film 20 before and after the continuous folding test is 3 or less.

A continuous folding test of the conductive film 20 can be performed using a sample cut out from the conductive film 20 to a predetermined size (for example, a rectangular shape of 125 mm long×50 mm wide). If the sample cannot be cut into a size of 125 mm long by 50 mm, the sample may be cut out to a size of 110 mm long by 50 mm wide, for example. Specifically, first, a sample of a predetermined size is cut out from the conductive film 20 before the continuous folding test. Then, on both ends of the conductive portion 23 in the longitudinal direction of the cut sample (for example, each portion of 10 mm long×50 mm wide) and both ends of the conductive portion 23 (for example, each portion of 10 mm long×50 mm wide), an electric In order to prevent the measurement distance of the resistance value from fluctuating, silver paste (product name "DW-520H-14", manufactured by Toyobo Co., Ltd.) is applied to each, heated at 130 ° C. for 30 minutes, and on the conductive part of the sample. A hardened silver paste is applied to both ends of the sample, and in that state, the electrical resistance value of the conductive part of the sample is measured using a tester (product name “Digital MΩ Hitester 3454-11” manufactured by Hioki Electric Co., Ltd.). . When measuring the electrical resistance of the conductive portion 23 , the probe terminals of the tester are brought into contact with the hardened silver paste provided on both ends of the conductive portion 23 . After measuring the electrical resistance value of the conductive portion 23 of the sample before the continuous folding test, the sample is subjected to the continuous folding test.

A continuous folding test is performed as follows. As shown in FIG. 3A, in the continuous folding test, first, the side S1 of the sample S and the side S2 opposite to the side S1 are fixed by the fixing portions 40 arranged in parallel. In addition, as shown in FIG. 3A, the fixed portion 40 is slidable in the horizontal direction.

Next, as shown in FIG. 3B, by moving the fixing portions 40 closer to each other, the conductive portion 23 is turned inside, and the sample S is deformed so as to be folded at the central portion S3. As shown in FIG. 3C, after moving the fixing part 40 to a position where the distance between the two facing sides S1 and S2 fixed by the fixing part 40 of the sample S is 4 mm, the fixing part 40 is removed. Deformation of the sample S is eliminated by moving in the opposite direction.

By moving the fixing portion 40 as shown in FIGS. 3A to 3C, the sample S can be folded 180° at the central portion S3 so that the conductive portion 23 is on the inside. In addition, a continuous folding test was performed so that the bent portion S4 of the sample S did not protrude from the lower end of the fixed portion 40, and the interval when the fixed portion 40 was closest was controlled to 4 mm. The distance between the two sides S1, S2 can be 4 mm. In this case, the outer diameter of the bent portion S4 is assumed to be 6 mm. Note that the thickness of the sample S is sufficiently small compared to the interval (4 mm) between the fixed portions 40, so the results of the continuous folding test of the sample S are not affected by the difference in the thickness of the sample S. can be regarded as

After performing the continuous folding test, the electrical resistance value of the conductive portion 23 is measured in the sample after the continuous folding test in the same manner as the sample before the continuous folding test. Then, the ratio of the electrical resistance value of the conductive portion 23 of the sample S after the continuous folding test to the electrical resistance value of the conductive portion 23 of the sample before the continuous folding test (the electrical resistance value of the conductive portion 23 of the sample S after the continuous folding test /Electric resistance value of the conductive portion 23 of the sample S before the continuous folding test) is obtained. The electrical resistance value ratio is the arithmetic mean value of the values obtained by measuring three times.

The conductive film 20 preferably has a haze value (total haze value) of 5% or less. If the haze value of the conductive film 20 is 5% or less, sufficient optical performance can be obtained. The haze value can be measured using a haze meter (product name "HM-150", manufactured by Murakami Color Research Laboratory) in accordance with JIS K7136:2000. The haze value is a value when measured on the entire conductive film, and after cutting it into a size of 50 mm long x 100 mm wide, it is placed in a state where there are no curls or wrinkles and no fingerprints or dust. Arithmetic mean value of values obtained by measuring three times for one adhesive film. In this specification, "measure three times" means not measuring the same place three times but three different places. The conductive film 20 has a flat surface 20A and a rear surface 20B that are visually observed, and the laminated layers such as the conductive portion 23 are also flat. falls within the range of ±5%. Therefore, by measuring the haze value at three different points of the cut conductive film, it is considered that the approximate average value of the haze values of the entire in-plane of the conductive film can be obtained. If the conductive film cannot be cut into the above size, for example, the HM-150 has an inlet opening of 20 mmφ for measurement, so a sample with a diameter of 21 mm or more is required. Therefore, the conductive film may be appropriately cut into a size of 22 mm×22 mm or more. When the size of the conductive film is small, the measurement points are set to three by gradually shifting or changing the angle within the range where the light source spot does not deviate. The haze value of the conductive film 20 is more preferably 3% or less, 2% or less, 1.5% or less, 1.2% or less, and 1.1% or less in this order (the smaller the value, the more preferable). The variation in the obtained haze value is within ±30% of the average value of the haze value, even if the measurement object is as long as 1 m × 3000 m or as large as a 5-inch smartphone, and is preferable. When falling within the range, low haze and low resistance are more likely to be obtained. Although the conductive portion 23 of the conductive film 20 is not patterned, the haze value of the conductive film including the patterned conductive portion is 5% or less, 3% or less, or 2% or less. , 1.5% or less, 1.2% or less, and 1.1% or less, in that order (the smaller the number, the better). In addition, it is preferable that the haze value is the same as the above even in the entire laminated body in which a plurality of layers are stacked, such as a touch panel sensor on which a conductive film is mounted.

The conductive film 20 preferably has a total light transmittance of 80% or more. If the total light transmittance of the conductive film is 80% or more, the optical performance will be sufficient. The total light transmittance can be measured according to JIS K7361-1:1997 using a haze meter (product name "HM-150", manufactured by Murakami Color Research Laboratory). The total light transmittance is the value when the conductive film is measured as a whole, and after cutting it into a size of 50 mm long x 100 mm wide, it is installed in a state where there are no curls, wrinkles, fingerprints, dust, etc. , the arithmetic mean value of the values obtained by measuring three times for one conductive film. The conductive film 20 has a flat surface 20A and a rear surface 20B that are visually observed, and the laminated layers such as the conductive portion 23 are also flat. falls within the range of ±5%. Therefore, by measuring the total light transmittance at three different points of the cut conductive film, it is considered that an approximate average value of the total light transmittance of the entire in-plane of the conductive film can be obtained. If the conductive film cannot be cut into the above size, for example, the HM-150 has an inlet opening of 20 mmφ for measurement, so a sample with a diameter of 21 mm or more is required. Therefore, the conductive film may be appropriately cut into a size of 22 mm×22 mm or more. When the size of the conductive film is small, the measurement points are set to three by gradually shifting or changing the angle within the range where the light source spot does not deviate. The total light transmittance of the conductive film 10 is more preferably 85% or more, 88% or more, and 89% or more, in that order (the larger the value, the more preferable). Although the conductive portion 23 of the conductive film 20 is not patterned, the total light transmittance of the conductive film including the patterned conductive portion is 80% or more, 85% or more, 88% or more, The order of 89% or more is preferable (the larger the numerical value, the more preferable). The variation in the total light transmittance obtained is within ±10% of the average value of the total light transmittance, even if the measurement object is as long as 1 m × 3000 m or as large as a 5-inch smartphone. Yes, and within the above preferred range, low haze and low resistance value are more likely to be obtained. In addition, it is preferable that the total light transmittance is the same as the above even in the entire laminated body in which a plurality of layers are stacked, such as a touch panel sensor on which a conductive film is mounted.

The back surface 20B of the conductive film 20 preferably has a pencil hardness of H or higher in a pencil hardness test defined by JIS K5600-5-4:1999. When the pencil hardness of the back surface 20B of the conductive film 20 is H or more, the conductive film 20 is hard, and durability can be improved. In the pencil hardness test, the conductive film 20 was cut into a size of 50 mm long x 100 mm wide, and the resin layer 22 was placed on the glass plate so that there were no creases or wrinkles. ), a load of 750 g is applied to the pencil, and the scratching speed is set to 1 mm/sec. The pencil hardness of the back surface 20B of the conductive film 20 was the highest hardness that did not scratch the surface 22A of the resin layer 22 in the pencil hardness test. In addition, when measuring the pencil hardness, a plurality of pencils with different hardness are used. If not, it is determined that the surface 22A of the resin layer 22 was not scratched by the pencil with this hardness. The above-mentioned flaw refers to a flaw visually recognized when the surface of the conductive film 20 subjected to the pencil hardness test is observed through transmission under a fluorescent lamp.

The conductive film 20 preferably has a yellow index (YI) of 15 or less. If the YI of the conductive film 20 is 15 or less, the yellow tint of the conductive film 20 can be suppressed, and it can be applied to applications requiring transparency. The yellow index (YI) is a spectrophotometer (product name "UV-3100PC", manufactured by Shimadzu Corporation, light source: tungsten lamp and deuterium lamp). The chromaticity tristimulus values X, Y, and Z were calculated according to the formula described in JIS Z8722: 2009 from the transmittance of the conductive film measured with the layer side facing the light source at wavelengths of 300 nm to 780 nm. , tristimulus values X, Y, and Z according to the formula described in ASTM D1925:1962. The upper limit of the yellow index (YI) of the conductive film 20 is more preferably 10 or less, 7 or less, or 3 or less (the smaller the value, the better). The yellow index (YI) is the arithmetic mean value of the values obtained by measuring three times for one conductive film. In the UV-3100PC, the yellow index is calculated by reading the transmittance measurement data on the monitor connected to the UV-3100PC and checking the "YI" item in the calculation items. . Measurement of the transmittance at a wavelength of 300 nm to 780 nm shall be obtained by measuring the transmittance for at least 5 points between 1 nm before and after each of the wavelengths of 300 nm to 780 nm under the following conditions, and calculating the average value. . If the spectrum of the spectral transmittance has undulations, a smoothing process may be performed with a delta of 5.0 nm. If the above size cannot be cut out, it may be 3 cm square or larger.
(Measurement condition)
・Wavelength range: 300 nm to 780 nm
・Scanning speed: high speed ・Slit width: 2.0
・Sampling interval: Auto (0.5 nm interval)
・Lighting: C
- Light source: D2 and WI
・Field of view: 2°
・Light source switching wavelength: 360 nm
・S/R switching: standard ・Detector: PM
Autozero: performed at 550 nm after baseline scan

The thickness of the conductive film 20 is preferably 25 μm or more and 500 μm or less. If the thickness of the conductive film 20 is 25 μm or more, the handleability is good, and if it is 100 μm or less, it is favorable from the viewpoint of thinning. The lower limit of the thickness of the conductive film 10 with protective film is more preferably 40 µm or more, and the upper limit is more preferably 250 µm or less, 100 µm or less, or 70 µm or less (the smaller the value, the better). The thickness of the conductive film is obtained by randomly measuring ten thicknesses from a cross-sectional photograph of the conductive film taken using a scanning electron microscope (SEM), and calculating the average value of the measured thicknesses.

The use of the conductive film 20 is not particularly limited, and for example, it may be used in various uses (for example, sensor use) where a transparent conductive film is used. In addition, the conductive film of the present invention can be used for image display devices (smartphones, tablet terminals, wearable terminals, personal computers, televisions, digital signage, public information displays (PID), in-vehicle displays, etc.) and in-vehicle (trains and (including all vehicles, such as vehicle construction machinery). When the conductive film 20 is used as an in-vehicle sensor, for example, it may be a sensor arranged in a portion touched by a person such as a steering wheel or a seat. The conductive film 20 is also preferable for applications requiring flexibility such as foldable and rollable. Further, it may be used for electrical appliances and windows used in homes and vehicles (including all types of vehicles such as trains and vehicle construction machinery). In particular, the conductive film of the present invention can be suitably used in areas where transparency is emphasized. In addition, the conductive film of the present invention can be suitably used not only for technical aspects such as transparency, but also for electrical appliances that require good design. Specific uses of the conductive film of the present invention include, for example, defrosters, antennas, solar cells, audio systems, speakers, fans, electronic blackboards, and carrier films for semiconductors. The conductive film 20 is used with the protective film 30 removed. The shape of the conductive film 20 in use is appropriately designed according to the application, and is not particularly limited, but may be curved, for example.

The conductive film may be cut into a desired size, or may be in the form of a roll. When the conductive film of the present invention is cut to a desired size, the size of the conductive film is not particularly limited, and is appropriately determined according to the size of the display surface of the image display device. Specifically, the size of the conductive film may be, for example, 5 inches or more and 500 inches or less. As used herein, "inch" means the length of the diagonal when the conductive film is square, the diameter when it is circular, and the length when it is elliptical. It shall mean the average value of the sum of diameter and major diameter. Here, when the conductive film has a square shape, the aspect ratio of the conductive film when calculating the above inch is not particularly limited as long as there is no problem with the display screen of the image display device. For example, height:width=1:1, 4:3, 16:10, 16:9, 2:1, and the like. However, particularly in in-vehicle applications and digital signage, which are rich in design, the aspect ratio is not limited to such an aspect ratio. In addition, when the size of the conductive film 10 is large, after cutting it from an arbitrary position into an appropriately manageable size such as A4 size (210 mm × 297 mm) or A5 size (148 mm × 210 mm), the size of each measurement item is measured. shall be cut into pieces.

<<Light transmissive substrate>>
The light-transmitting base material 21 includes a base material body 21C and a base layer 21D formed on the surface of the base material body 21C on the resin layer 22 side. Although the light-transmitting base material 21 has the underlying layer 21D on the resin layer 22 side of the base material body 21C, the underlying layer 21D may not be provided. In this case, the light-transmissive substrate is composed only of the substrate body. Further, the base layer may be provided not only on the resin layer side surface of the substrate main body but also on both the conductive portion side surface thereof. However, when a conductive portion is formed on the surface of an underlayer using a conductive fiber-containing composition containing conductive fibers and a dispersion medium, the dispersion medium permeates into the underlayer, although the extent varies depending on the type of dispersion system. Due to this, the conductive fibers may also enter the base layer and the surface resistance value may increase. It is preferably provided directly.

The thickness of the light-transmitting substrate 21 is not particularly limited, but it can be 3 μm or more and 500 μm or less. More preferred (the higher the number, the better). From the viewpoint of thinning, the upper limit of the thickness of the light transmissive substrate 21 is more preferably 250 μm or less, 100 μm or less, 80 μm or less, 60 μm or less, or 40 μm or less (the smaller the value, the better). The thickness of the light-transmitting substrate can be measured by the same method as the method for measuring the film thickness of the conductive portion, which will be described later.

<Base material body>
As the substrate main body 21C, a substrate made of a resin having optical transparency can be used. Such resins are not particularly limited as long as they have optical transparency. resins, acetylcellulose resins, polyimide resins, polyamideimide resins, polyamide resins, or mixtures of two or more of these resins. The base material body is easily scratched because it touches the coating equipment when coating the resin layer, etc., but the base material body made of polyester resin is not easily damaged even if it touches the coating equipment, so the haze value is reduced. Of these, polyester-based resins are preferred because they can suppress the increase in heat resistance, barrier properties, and water resistance as compared to substrate bodies made of light-transmitting resins other than polyester-based resins.

In the case of obtaining a foldable conductive film as the conductive film, polyimide-based resin, polyamide-imide-based resin, polyamide-based resin, polyimide-based resin, polyamide-based resin, polyimide-based resin, polyimide-based resin, polyamide-based resin, etc., can be used as the resin constituting the base body 21C because of their good foldability. It is preferable to use a polyester resin or a mixture thereof. In addition, among these, it not only has excellent folding properties, but also has excellent hardness and transparency, and also has excellent heat resistance, and by firing, it imparts even better hardness and transparency. Polyimide-based resins, polyamide-based resins, or mixtures thereof are preferred because they can also be used.

Examples of polyolefin-based resins include polyethylene, polypropylene, and cyclic polyolefin base materials. Examples of cyclic polyolefin resins include those having a norbornene skeleton.

Examples of polycarbonate-based resins include aromatic polycarbonates based on bisphenols (bisphenol A, etc.), aliphatic polycarbonates such as diethylene glycol bisallyl carbonate, and the like.

Examples of polyacrylate resins include polymethyl (meth)acrylate, polyethyl (meth)acrylate, methyl (meth)acrylate-butyl (meth)acrylate copolymer, and the like.

Examples of polyester-based resins include at least one of polyethylene terephthalate (PET), polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate (PEN).

Examples of aromatic polyetherketone-based resins include polyetheretherketone (PEEK).

Acetylcellulose resins include, for example, triacetylcellulose (TAC) and diacetylcellulose. Triacetyl cellulose is a resin capable of having an average light transmittance of 50% or more in the visible light range of 380 to 780 nm. The average light transmittance of triacetyl cellulose is preferably 70% or more, more preferably 85% or more.

In addition to pure triacetyl cellulose, the triacetyl cellulose may be cellulose acetate propionate, cellulose acetate butyrate, or other fatty acid that forms an ester with cellulose in addition to acetic acid. If necessary, these triacetyl cellulose resins may contain other lower fatty acid esters of cellulose such as diacetyl cellulose, or various additives such as plasticizers, ultraviolet absorbers, and lubricants.

The polyimide resin may partially contain a polyamide structure. Polyamide-based resin is a concept that includes not only aliphatic polyamides but also aromatic polyamides (aramids). A commercially available substrate may be used as the base material made of polyimide resin and the base material made of polyamide resin. Examples of commercially available base materials made of polyimide resins include Neoprim manufactured by Mitsubishi Gas Chemical Co., Ltd. Examples of commercially available base materials composed of polyamide resins include Miktron manufactured by Toray Industries, Inc. is mentioned.

The surface of the substrate main body 21C may be subjected to a physical treatment such as corona discharge treatment, oxidation treatment, or the like in order to improve adhesiveness.

<Underlayer>
The base layer 21D is a layer having a function of improving adhesion with other layers, a function of preventing sticking during winding, and/or a function of suppressing repelling of the coating liquid forming other layers. . Whether or not the light-transmitting substrate has an underlayer can be determined using a scanning electron microscope (SEM), a scanning transmission electron microscope (STEM), or a transmission electron microscope (TEM). It can be confirmed by observing the cross section around the interface between the light-transmitting substrate and the resin layer and around the interface between the light-transmitting substrate and the conductive part at a magnification of 25,000 to 50,000 times. . The undercoat layer may contain particles such as a lubricant to prevent sticking during winding. It can be determined that this is the underlying layer.

The film thickness of the underlying layer 21D is preferably 10 nm or more and 1 μm or less. If the film thickness of the underlying layer 21D is 10 nm or more, the function of the underlying layer 21D can be fully exhibited, and if the film thickness of the underlying layer 21D is 1 μm or less, there is no possibility that it will have an optical effect. The film thickness of the underlayer is 1,000 to 500,000 times, preferably 25,000 to 5,000 times using a scanning electron microscope (SEM), scanning transmission electron microscope (STEM), or transmission electron microscope (TEM). 10 thicknesses are randomly measured from a cross-sectional photograph of the underlayer taken at a magnification of 10,000, and the thickness at the 10 measured points is taken as an arithmetic mean value. More preferably, the lower limit of the film thickness of the underlying layer 21D is 30 nm or more, and the upper limit is 150 nm or less. The film thickness of the underlying layer can also be measured by the same method as for the film thickness of the conductive portion 23 .

The underlying layer 21D contains, for example, an anchor agent or a primer agent. Anchor agents and primer agents include, for example, polyurethane resins, polyester resins, polyvinyl chloride-based resins, polyvinyl acetate-based resins, vinyl chloride-vinyl acetate copolymers, acrylic resins, polyvinyl alcohol-based resins, polyvinyl acetal resins, and ethylene. and vinyl acetate or acrylic acid, etc., copolymers of ethylene and styrene and/or butadiene, etc., thermoplastic resins such as olefin resins and/or their modified resins, polymers of ionizing radiation polymerizable compounds, and at least one of polymers of thermally polymerizable compounds.

The base layer 21D may contain particles such as a lubricant to prevent sticking during winding as described above. Examples of the particles include silica particles.

<<resin layer>>
The resin layer 22 is adjacent to the base layer 21D. Adhesion between the resin layer 22 and the light-transmitting substrate 21 can be improved by adjoining the resin layer 22 to the base layer 21D. A "resin layer" as used herein is a layer containing at least a resin. The resin layer 22 is preferably a hard coat layer. As used herein, the term "hard coat layer" means a layer that has optical transparency and is harder than the optically transparent substrate. Specifically, when the resin layer 22 is a hard coat layer, the Martens hardness of the resin layer 22 is higher than the Martens hardness of the light transmissive substrate 21 . The Martens hardness of the resin layer is measured using a microhardness tester (product name “PICODENTOR HM500” manufactured by Fisher Instruments, ISO14577-1, ASTM E2546 compliant) measurement sample. Specifically, first, a block is prepared by embedding a conductive film with a protective film cut into 1 mm × 10 mm with an embedding resin, and a uniform thickness without holes is produced from this block by a general section preparation method. Sections of 70 nm or more and 100 nm or less are cut out. "Ultramicrotome EM UC7" (Leica Microsystems, Inc.) is used to prepare the sections. Then, the remaining block from which uniform sections without holes or the like were cut out is used as a sample for measurement. Then, this measurement sample is fixed to the measurement stage of a microhardness tester placed parallel to a vibration isolation table. After fixing the measurement sample to the measurement stage of the microhardness tester, the Martens hardness of the cross-section of the resin layer at a depth of 100 nm is measured under the following measurement conditions. The Martens hardness is the arithmetic mean value of the hardness of the three points obtained by measuring arbitrary three points near the center of the cross section of the resin layer of the measurement sample. In addition, when calculating the Martens hardness, it is automatically calculated by selecting "HM" (Martens hardness) as the type of hardness to be measured with the Picodenter HM500. The Martens hardness of the light-transmitting substrate can also be measured by the same method as the Martens hardness of the resin layer.
(Measurement condition)
・Indenter shape: Vickers (quadrangular pyramid diamond indenter) (regular quadrangular pyramid with a facing angle of 136° at the tip)
・Load control method: up to a maximum load of 40 mN ・Load increase time: 20 seconds ・Creep time: 5 seconds ・Load removal time: 20 seconds ・Push amount: 100 nm
・Temperature at the time of measurement: 25°C
・ Humidity at the time of measurement: 50%
The profile of the measurement is to apply a load from 0 mN to 40 mN over 20 seconds, hold 40 mN for 5 seconds, and then return from 40 mN to 0 mN over 20 seconds.

The film thickness of the resin layer 22 is preferably 0.5 μm or more and 15 μm or less. If the film thickness of the resin layer 22 is 0.5 μm or more, desired hardness can be obtained, and if the film thickness of the resin layer 22 is 15 μm or less, the thickness of the conductive film 20 can be reduced. . The film thickness of the resin layer 22 can be measured by the same method as the thickness of the light transmissive substrate 21 . From the viewpoint of suppressing the occurrence of curling, the lower limit of the film thickness of the resin layer 22 is more preferably 1 μm or more, 1.5 μm or more, and 2 μm or more, in that order (the larger the value, the more preferable). From the viewpoint of suppressing cracking of the resin layer 22, the upper limit of the film thickness of the resin layer 22 is more preferably 12 μm or less, 10 μm or less, 7 μm or less, and 5 μm or less in this order (smaller values are more preferable). From the viewpoint of suppressing the occurrence of curling while reducing the thickness of the resin layer 22, the film thickness of the resin layer 22 is more preferably 0.5 μm or more and 10 μm or less.

The resin layer 22 can be composed of at least resin. The resin layer 22 may contain inorganic particles, organic particles and a leveling agent in addition to the resin.

<Resin>
Examples of the resin forming the resin layer 22 include those containing a polymer (cured product, crosslinked product) of a polymerizable compound. The resin may contain a solvent-drying type resin in addition to the polymer of the polymerizable compound. Polymerizable compounds include ionizing radiation polymerizable compounds and/or thermally polymerizable compounds.

The ionizing radiation-polymerizable compound is a compound having at least one ionizing radiation-polymerizable functional group in one molecule. The term "ionizing radiation-polymerizable functional group" as used herein is a functional group capable of undergoing a polymerization reaction upon exposure to ionizing radiation. Examples of ionizing radiation-polymerizable functional groups include ethylenically unsaturated groups such as (meth)acryloyl groups, vinyl groups, and allyl groups. In addition, "(meth)acryloyl group" is meant to include both "acryloyl group" and "methacryloyl group". Examples of the ionizing radiation irradiated when polymerizing the ionizing radiation-polymerizable compound include visible light, ultraviolet rays, X-rays, electron beams, α rays, β rays, and γ rays.

Examples of the ionizing radiation-polymerizable compound include ionizing radiation-polymerizable monomers, ionizing radiation-polymerizable oligomers, and ionizing radiation-polymerizable prepolymers, and these can be appropriately adjusted and used. As the ionizing radiation-polymerizable compound, a combination of an ionizing radiation-polymerizable monomer and an ionizing radiation-polymerizable oligomer or ionizing radiation-polymerizable prepolymer is preferable.

Examples of ionizing radiation-polymerizable monomers include monomers containing hydroxyl groups such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate, and ethylene glycol di(meth)acrylate. , diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, tetramethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth) ) acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, glycerol (meth)acrylate (Meth)acrylic acid esters such as

As the ionizing radiation-polymerizable oligomer, a polyfunctional oligomer having two or more functional groups is preferable, and a polyfunctional oligomer having three (trifunctional) or more ionizing radiation-polymerizable functional groups is preferable. Examples of the polyfunctional oligomer include polyester (meth)acrylate, urethane (meth)acrylate, polyester-urethane (meth)acrylate, polyether (meth)acrylate, polyol (meth)acrylate, melamine (meth)acrylate, and isocyanurate. (Meth)acrylate, epoxy (meth)acrylate and the like.

The ionizing radiation polymerizable prepolymer may have, for example, a weight average molecular weight of 10,000. The weight average molecular weight of the ionizing radiation polymerizable prepolymer is preferably 10,000 or more and 80,000 or less, more preferably 10,000 or more and 40,000 or less. When the weight-average molecular weight exceeds 80,000, the viscosity is high, so that the coatability is lowered, and the appearance of the resulting resin layer may be deteriorated. Polyfunctional prepolymers include urethane (meth)acrylate, isocyanurate (meth)acrylate, polyester-urethane (meth)acrylate, epoxy (meth)acrylate and the like.

A thermally polymerizable compound has at least one thermally polymerizable functional group in one molecule. The term "thermally polymerizable functional group" as used herein refers to a functional group capable of undergoing a polymerization reaction between the same functional groups or another functional group by heating. Thermally polymerizable functional groups include hydroxyl groups, carboxyl groups, isocyanate groups, amino groups, cyclic ether groups, mercapto groups, and the like.

The thermally polymerizable compound is not particularly limited, and examples thereof include epoxy compounds, polyol compounds, isocyanate compounds, melamine compounds, urea compounds, phenol compounds and the like.

Solvent-drying type resins are resins such as thermoplastic resins that form a film only by drying the solvent added to adjust the solid content at the time of coating. When the solvent-drying type resin is added, when forming the resin layer 22, it is possible to effectively prevent film defects on the coating surface of the coating liquid. The solvent-drying type resin is not particularly limited, and generally thermoplastic resins can be used.

Examples of thermoplastic resins include styrene-based resins, (meth)acrylic-based resins, vinyl acetate-based resins, vinyl ether-based resins, halogen-containing resins, alicyclic olefin-based resins, polycarbonate-based resins, polyester-based resins, and polyamide-based resins. , cellulose derivatives, silicone resins and rubbers or elastomers.

The thermoplastic resin is preferably amorphous and soluble in an organic solvent (especially a common solvent capable of dissolving a plurality of polymers and curable compounds). In particular, from the viewpoint of transparency and weather resistance, styrene-based resins, (meth)acrylic-based resins, alicyclic olefin-based resins, polyester-based resins, cellulose derivatives (cellulose esters, etc.), and the like are preferable.

<Inorganic particles>
Inorganic particles are components for improving the mechanical strength and pencil strength of the resin layer 22. Examples of inorganic particles include silica (SiO ₂ ) particles, alumina particles, titania particles, tin oxide particles, antimony-doped oxide particles, and the like. Inorganic oxide particles such as tin (abbreviation: ATO) particles and zinc oxide particles are included. Among these, silica particles are preferable from the viewpoint of increasing hardness. Examples of silica particles include spherical silica particles and irregularly shaped silica particles, and among these, irregularly shaped silica particles are preferred. The term "spherical particles" as used herein means, for example, particles in the shape of a true sphere, an ellipsoid, or the like, and the term "irregularly shaped particles" means particles having random potato-like unevenness on the surface. Since the irregular-shaped particles have a larger surface area than spherical particles, the inclusion of such irregular-shaped particles increases the contact area with the polymerizable compound and the like, and the pencil hardness of the resin layer 22 is improved. can be assumed. Whether or not the silica particles contained in the resin layer 22 are deformed silica particles is confirmed by observing the cross section of the resin layer 22 with a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). be able to. When spherical silica particles are used, the smaller the particle size of the spherical silica particles, the higher the hardness of the resin layer. In contrast, irregularly shaped silica particles are not as small as the smallest commercially available spherical silica particles, but can achieve hardness equivalent to this spherical silica.

The average primary particle size of the irregularly shaped silica particles is preferably 1 nm or more and 100 nm or less. Even if the average primary particle size of the irregularly shaped silica particles is within this range, hardness equivalent to that of spherical silica having an average primary particle size of 1 nm or more and 45 nm or less can be achieved. The average primary particle diameter of the irregularly shaped silica particles is determined from an image of the cross section of the resin layer taken using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). The maximum value (major axis) and the minimum value (minor axis) of the distance are measured and averaged to determine the particle size, which is taken as the arithmetic mean value of the particle sizes of 20 particles. In addition, the average particle size of the spherical silica particles is obtained by measuring the particle size of 20 particles from a cross-sectional image of the particles taken using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). Arithmetic mean value of particle diameters of individual particles. When taking a cross-sectional photograph using a scanning transmission electron microscope (STEM) (product name “S-4800 (TYPE2)”, manufactured by Hitachi High-Technologies Corporation), the detector (selection signal) is set to “TE ”, the acceleration voltage is set to “30 kV”, and the emission is set to “10 μA”. For other conditions for photographing a cross-sectional photograph by STEM, the conditions described later can be referred to. Incidentally, the average primary particle diameter can also be calculated by binarizing image data as described later.

The content of the inorganic particles in the resin layer 22 is preferably 20% by mass or more and 70% by mass or less. If the content of the inorganic particles is 20% by mass or more, sufficient hardness can be obtained, and if the content of the inorganic particles is 70% by mass or less, the filling rate does not increase too much, and the inorganic particles and the resin component Since the adhesiveness to the resin layer is good, the hardness of the resin layer is not lowered.

As the inorganic particles, it is preferable to use inorganic particles (reactive inorganic particles) having ionizing radiation-polymerizable functional groups on their surfaces. Such inorganic particles having ionizing radiation-polymerizable functional groups on their surfaces can be produced by surface-treating inorganic particles with a silane coupling agent or the like. Methods for treating the surface of inorganic particles with a silane coupling agent include a dry method in which the silane coupling agent is sprayed onto the inorganic particles, and a wet method in which the inorganic particles are dispersed in a solvent and then the silane coupling agent is added for reaction. etc.

<Organic particles>
Organic particles are also components for improving the mechanical strength and pencil strength of the resin layer 22, and examples of organic particles include plastic beads. Specific examples of plastic beads include polystyrene beads, melamine resin beads, acrylic beads, acrylic-styrene beads, silicone beads, benzoguanamine beads, benzoguanamine/formaldehyde condensed beads, polycarbonate beads, and polyethylene beads.

<<Conductive Part>>
The conductive portion 23 includes conductive fibers 24, as shown in FIG. The conductive portion 23 contains a light-transmitting resin 25 in addition to the conductive fibers 24 . However, the conductive portion does not need to contain the light-transmitting resin as long as it contains conductive fibers. As used herein, the term “conductive portion” means a layer containing conductive fibers when a cross section is observed using a scanning transmission electron microscope (STEM) or a transmission electron microscope (TEM). If it is difficult to confirm the interface of the conductive portion, it is preferable to perform a pretreatment generally used for electron microscope observation, such as forming a metal layer of Pt—Pd, Au, or the like on the surface of the conductive portion by sputtering. In addition, when the conductive film is dyed with osmium tetroxide, ruthenium tetroxide, or phosphotungstic acid, the interface between the organic layers becomes easier to see.

Conductive fibers 24 are arranged in light-transmitting resin 25 . The term "conductive fiber" as used herein refers to a fiber that is conductive and has a shape whose length is sufficiently longer than its thickness (e.g., diameter). Those with 5 times or more shall be included in the conductive fiber.

The surface resistance value of the conductive portion 23 is preferably 3Ω/□ or more and 1000Ω/□ or less. If the surface resistance value of the conductive portion 23 is 3Ω/□ or more, the optical performance is sufficient. It is possible to suppress the occurrence of defects such as The surface resistance value of the conductive portion 23 is measured using a contact-type resistivity meter (product name: Loresta AX MCP-T370 model, stock Mitsubishi Chemical Analytech, terminal shape: ASP probe) and non-contact type (eddy current method) resistivity meter (product name “EC-80P”, Napson Co., Ltd., https://www.napson.co.jp) jp/wp/wp-content/uploads/2016/08/Napson_EC80P_leaflet_160614.pdf), but since it can be measured accurately regardless of the film thickness of the conductive part, it is non-destructive It is preferably measured using a resistivity meter of the formula. The probe of the non-destructive resistivity meter can be measured by simply contacting the sample, and can be measured at any place without damaging the sample. In that sense, it is sometimes called a non-contact type. The surface resistance value of the conductive part is measured by a non-destructive resistivity meter. A conductive film cut into a size of 80 mm × 50 mm is placed on a flat glass plate so that the conductive part side faces up, and the probe shall be in contact with the conductive part. When measuring the surface resistance value using EC-80P, select SW2 and select sheet resistance measurement Ω/□ in mode MH. Further, the probe type can be easily changed according to the measurement range. In this embodiment, a probe with a measurement range of 10 to 1000Ω/□ and a probe with a measurement range of 0.5 to 10Ω/□ are used. Note that EC-80P-PN (manufactured by Napson Co., Ltd.) can be used instead of EC-80P for similar measurements, but in the case of this model, P should be selected for P/N. In addition, the surface resistance value of the conductive part is measured by a contact-type resistivity meter. This shall be done by placing the ASP probe in the center of the conductive part and pressing all the electrode pins evenly against the conductive part. When measuring the surface resistance value with a contact-type resistivity meter, select Ω/□, which is the mode for measuring sheet resistance. After that, press and hold the start button to display the measurement results. Regardless of the type of resistivity meter, the surface resistance value shall be measured in an environment of 23° C. and 55% relative humidity. Also, when measuring the surface resistance value, regardless of the type of resistivity meter, the conductive film is placed on a horizontal desk and measured in a uniform flat state, but the conductive film curls. If it is not possible to maintain an equiplanar state, the conductive film shall be attached to the glass plate with tape or the like. The measurement points are three points at the center of the conductive film, and the surface resistance value is the arithmetic mean value of the surface resistance values at the three points. Here, according to JIS K7194: 1994, the number of measurement points is 1 point, 5 points, or 9 points. If you measure according to , the measured value may become unstable. For this reason, unlike JIS K7194:1994, measurement is performed at three points in the center of the conductive portion. For example, position No. 1 in FIG. 5 of JIS K7194: 1994, a position between Nos. 1 and 7 (preferably the position closest to No. 1), and a position between Nos. 1 and 9 (preferably No. 1 (nearest position). It is desirable to measure the surface resistance value near the center of the sample, Daichi Isaka and one other person, "Resistivity measurement of conductive thin film by four-probe method" 2008 Institute of Electronics, Information and Communication Engineers Tokyo branch student research presentation (https://www.ieice.org/tokyo/gakusei/kenkyuu/14/pdf/120.pdf). The lower limit of the surface resistance value of the conductive portion 23 is preferably 1 Ω/square or more, 5 Ω/square or more, and 10 Ω/square or more, in that order (the larger the value, the more preferable). □ or less, 100 Ω/□ or less, 70 Ω/□ or less, 60 Ω/□ or less, and 50 Ω/□ or less, in that order (the smaller the value, the better).

The wire resistance value of the conductive portion 23 is preferably 60Ω or more and 20000Ω or less. If the line resistance value of the conductive portion 23 is 60 Ω or more, the optical performance is sufficient, and if the line resistance value of the conductive portion 23 is 20000 Ω or less, problems such as a slow response speed occur, especially in touch panel applications. can be suppressed. The line resistance value of the conductive portion 23 was measured by applying a tester (product name: “Digital MΩ Hitester 3454-11”, Hioki Electric Co., Ltd.) to both ends in the longitudinal direction of a rectangular sample with a width of 5 mm and a length of 100 mm cut from the conductive film. (manufactured) can be measured by contacting the probe terminal. Specifically, the Digital MΩ Hitester 3454-11 has two probe terminals (a red probe terminal and a black probe terminal, both pin-shaped), so the red probe terminal is attached to one end of the conductive part. The black probe terminal is brought into contact with the other end of the conductive portion to measure the line resistance value of the conductive portion. The lower limit of the line resistance value of the conductive portion 23 is more preferably 200Ω or more, and the upper limit of the line resistance value of the conductive portion 23 is more preferably 2000Ω or less.

The thickness of the conductive portion 23 is preferably less than 300 nm. If the film thickness of the conductive portion is 300 nm or more, the film thickness of the light-transmitting resin will be too thick. The conductive fibers are no longer exposed on the surface of the conductive portion, and there is a risk that electrical continuity cannot be obtained from the surface of the conductive portion. As the film thickness of the conductive part increases, the area where the conductive fibers overlap increases, so it is possible to achieve a low surface resistance value of 1Ω/□ or more and 10Ω/□ or less. Excessive overlap may make it difficult to maintain a low haze value. Therefore, the film thickness is preferably less than 300 nm. From the viewpoint of optical properties and thinning, the conductive portion is preferably a thin film as long as a low surface resistance value can be maintained. The upper limit of the film thickness of the conductive portion 23 is more preferably 145 nm, 140 nm or less, 120 nm or less, 110 nm or less, 80 nm or less, and 50 nm or less in order from the viewpoint of thinning and the viewpoint of obtaining good optical characteristics such as a low haze value ( lower numbers are better). Moreover, the lower limit of the film thickness of the conductive portion 23 is preferably 10 nm or more. If the film thickness of the conductive portion is less than 10 nm, the film thickness of the light-transmissive resin 25 will be too thin accordingly, so that the conductive fiber will detach from the conductive portion, the durability of the conductive portion will deteriorate, A decrease in scratch resistance may occur. Moreover, in order to prevent instability such as the conductive fiber being easily cut, it is preferable that the fiber diameter of the conductive fiber is large to some extent. It is considered that a fiber diameter of 10 nm or more or 15 nm or more is sufficient for the conductive fiber to stably maintain its shape. On the other hand, in order to obtain stable electrical conduction, it is desirable that two or more conductive fibers are in contact with each other. is more preferred.

The film thickness of the conductive portion 23 was measured by randomly measuring the film thickness at 10 locations from a cross-sectional photograph of the conductive portion taken using a scanning transmission electron microscope (STEM) or a transmission electron microscope (TEM). Arithmetic mean value of 10 film thicknesses. A specific method for taking cross-sectional photographs will be described below. First, a sample for cross-sectional observation is produced from the conductive film in the same manner as described above. It is preferable to sputter Pt--Pd for about 20 seconds because an STEM observation image may be difficult to see if conduction is not obtained in this sample. The sputtering time can be adjusted as appropriate, but 10 seconds is too short, and 100 seconds is too long, so that the sputtered metal forms a particle-like foreign matter image, so care must be taken. After that, using a scanning transmission electron microscope (STEM) (product name “S-4800 (TYPE2)” manufactured by Hitachi High-Technologies Corporation), a cross-sectional photograph of the STEM sample is taken. When taking this cross-sectional photograph, STEM observation is performed with the detector (selection signal) set to "TE", the acceleration voltage set to "30 kV", and the emission set to "10 μA". Magnification is appropriately adjusted between 5,000 and 200,000 times while adjusting the focus and observing whether each layer can be distinguished in terms of contrast and brightness. A preferable magnification is 10,000 to 100,000 times, more preferable magnification is 10,000 to 50,000 times, and the most preferable magnification is 25,000 to 50,000 times. When taking a cross-sectional photograph, the aperture is set to 3 for the beam monitor diaphragm, the objective lens diaphragm is set to 3, and the W.F. D. may be 8 mm. When measuring the film thickness of the conductive portion, it is important that the interface contrast between the conductive portion and other layers (resin layer, embedded resin, etc.) can be observed as clearly as possible when observing the cross section. If this interface is difficult to see due to insufficient contrast, a pretreatment generally used in electron microscope observation, such as forming a metal layer of Pt—Pd, Pt, Au, or the like on the surface of the conductive portion by a sputtering method, is performed. you can go In addition, dyeing treatment such as osmium tetroxide, ruthenium tetroxide, phosphotungstic acid or the like makes it easier to see the interface between the organic layers. Further, the interface contrast may be difficult to understand at high magnification. In that case, the low magnification is also observed at the same time. For example, observe at two high and low magnifications, such as 25,000 times and 50,000 times, or 50,000 times and 100,000 times, obtain the above arithmetic average value at both magnifications, and further calculate the average value of the conductive part. It is the film thickness value.

The conductive portion 23 preferably has a Martens hardness of 970 N/mm ² or more and 1050 N/mm ² or less at a position where the pushing amount from the surface 23A is 10 nm. Further, the conductive portion 23 preferably has a Martens hardness of 130 N/mm ² or more and 300 N/mm ² or less at a position where the pushing amount from the surface 23A is 100 nm. In general, when measuring with a microhardness tester, an indentation amount within 10% of the film thickness to be measured is preferable. That is, in the present embodiment, the Martens hardness at the 10 nm position means the hardness of the conductive portion itself, which is less affected by the underlying layer than the conductive portion. In general, in the product state, not only the conductive part but also various layers such as the base material are laminated under the film, but the Martens hardness at the 100 nm position is required when it becomes a product. It means the hardness as a film that No matter what kind of layer is placed under the conductive portion, if the above Martens hardness is satisfied, the conductive film is unlikely to be bent or cracked.

If the Martens hardness of the conductive portion 23 at the position where the pushing amount is 10 nm is less than 970 N/mm ² , the conductive film is easily scratched in the manufacturing process, and if it exceeds 1050 N/mm ² , the conductive The etching rate during patterning of the part becomes slow, and there is a possibility that cracks may occur due to bending. The lower limit of the Martens hardness at the position where the pushing amount in the conductive portion 23 is 10 nm is more preferably 980 N/mm ² or more, 1000 N/mm ² or more, and 1015 N/mm ² or more in this order (the larger the numerical value, the more preferable). The upper limit of the Martens hardness at the position of 10 nm is more preferable in the order of 1040 N/mm ² or less, 1030 N/mm ² or less, and 1020 N/mm ² or less (the smaller the value, the better). In addition, when the Martens hardness at the position where the indentation amount is 100 nm is less than 130 N/mm ² , the conductive film is likely to break, and when it exceeds 150 N/mm ² , cracking occurs when bending. There is a risk of The lower limit of the Martens hardness at the position where the pushing amount in the conductive portion 23 is 100 nm is more preferably 140 N/mm ² or more, 150 N/mm ² or more, and 170 N/mm ² or more in this order (the larger the value, the better), and the pushing amount. The upper limit of the Martens hardness at the position of 100 nm is more preferably 280 N/mm ² or less, 250 N/mm ² or less, and 200 N/mm ² or less, in that order (the smaller the value, the better).

In the present invention, it is preferable to satisfy at least one of the Martens hardness when the indentation amount is 10 nm or 100 nm. By satisfying both conditions, the balance of physical properties such as breakage and cracking is improved as described above. Also, it is important that the Martens hardness is neither too low nor too high. For example, in order to prevent the film from being easily damaged during the manufacturing process of the conductive film, a hardness of at least a certain level is required. Moreover, when patterning the conductive portion, an etching process is performed. This treatment includes dry etching using a laser or the like, and wet etching such as immersion in an etchant by a widely used photolithography method. In either etching, if the hardness is too high, the etching speed becomes slow, and the problem arises that processing takes a long time. Therefore, the upper limit of the Martens hardness is necessary.

The Martens hardness of the conductive portion with a pressing amount from the surface of 10 nm or 100 nm shall be measured by the following method. First, from a conductive film with a protective film cut into a size of 20 mm×20 mm, the protective film is completely peeled off to obtain a single conductive film. Then, it is fixed to a commercially available slide glass with an adhesive resin (product name “Aron Alpha (registered trademark) for general use”, manufactured by Toagosei Co., Ltd.) so that the conductive part side to be measured for Martens hardness faces up. Specifically, the adhesive resin is dripped onto the central portion of a slide glass 1 (product name: “Slide glass (cut-off type) 1-9645-11” manufactured by AS ONE Corporation). At this time, one droplet is dropped so as not to spread the adhesive resin and to prevent the adhesive resin from protruding from the conductive film when it is spread as described later. After that, the conductive film cut out to the above size is brought into contact with the slide glass so that the conductive portion side of the object to be measured faces upward and the adhesive resin is positioned at the center of the conductive film, and the slide glass 1 and the conductive film are placed. The adhesive resin is spread between and temporarily adhered. Then, another new slide glass 2 is placed on the conductive film to obtain a laminate of slide glass 1/adhesive resin/conductive film/slide glass 2. Next, a weight of 30 g or more and 50 g or less is placed on the slide glass 2, and left in that state at room temperature for 12 hours. After that, the weight and the slide glass 2 are removed, and this is used as a sample for measurement. Note that the four corners of the conductive film fixed with the adhesive resin may be further fixed with a tape (product name “CELLOTAPE (registered trademark)”, manufactured by Nichiban Co., Ltd.). Then, the measurement stage of a microhardness tester (product name “PICODENTOR HM500” manufactured by Fisher Instruments, conforming to ISO14577-1, ASTM E2546) in which this measurement sample is placed parallel to a vibration isolation table. fixed to This fixation can be done by any method such as fixing the four sides of the slide glass 1 with tape (product name “CELLOTAPE (registered trademark), manufactured by Nichiban Co., Ltd.”), and the sample for measurement should not move. If the hardness tester has an air suction system, it may be fixed by the air suction system.After fixing the measurement sample to the measurement stage of the microhardness tester, the conductive part is held under the following measurement conditions. Measure the Martens hardness at the depth of 10 nm and 100 nm on the surface respectively.The Martens hardness is obtained by measuring arbitrary five points near the center of the surface of the conductive part of the measurement sample (the area where the adhesive resin exists). The arithmetic mean value of the hardness of 5 points.However, any 5 points to be measured are measured by observing the conductive part at a magnification of 50 to 500 times using a microscope attached to Pico Dentor HM500. A patterned conductive film should be selected from flat parts as much as possible, avoiding areas where the fibers overlap to form an extremely convex structure and, on the contrary, areas with an extremely concave structure. In the conductive part of , select any 5 points to be measured in the same way as above.In addition, when calculating the Martens hardness, select "HM" (Martens hardness) as the hardness type you want to measure with the Picodenter HM500. Calculated automatically.
(Measurement condition)
・Indenter shape: Vickers (quadrangular pyramid diamond indenter) (regular quadrangular pyramid with a facing angle of 136° at the tip)
・Load control method: up to a maximum load of 40 mN ・Load increase time: 20 seconds ・Creep time: 5 seconds ・Load removal time: 20 seconds ・Push depth: 10 nm (when measuring Martens hardness at a depth of 10 nm), 100 nm (During measurement of Martens hardness at a depth of 100 nm)
・Temperature at the time of measurement: 25°C
・ Humidity at the time of measurement: 50%
The profile of the measurement is to apply a load from 0 mN to 40 mN over 20 seconds, hold 40 mN for 5 seconds, and then return from 40 mN to 0 mN over 20 seconds.

<Conductive fiber>
A plurality of conductive fibers 24 are preferably present in the conductive portion 23 . The conductive fibers 24 are electrically conductive from the surface 22</b>A of the conductive portion 23 , so the conductive fibers 24 are in contact with each other in the thickness direction of the conductive portion 23 .

In the conductive portion 23 , it is preferable that the conductive fibers 24 contact each other to form a network structure (mesh structure) in the planar direction (two-dimensional direction) of the conductive portion 23 . A conductive path can be formed by the conductive fibers 24 forming a network structure.

A part of the conductive fibers 24 is preferably exposed on the surface 23A of the conductive portion 23 . In addition, it suffices if a part of the conductive fiber 24 is exposed to the extent that the conductive fiber 24 is fixed to the conductive portion 23, and even if the conductive fiber 24 protrudes from the surface 22A of the conductive portion 23, it is not conductive. It is included when the fiber 24 is exposed on the surface 23A of the conductive portion 23 . If some of the conductive fibers are not exposed on the surface of the conductive portion, electrical continuity may not be obtained from the surface of the conductive portion. If so, it can be judged that a part of the conductive fibers 24 are exposed on the surface 23A of the conductive portion 23 . Whether or not the conductive fiber is electrically conductive from the surface of the conductive portion can be determined by measuring the surface resistance value of the conductive portion by the same method as described above. Specifically, if the arithmetic average value of the surface resistance values of the conductive portion is less than 1×10 ⁶ Ω/□, it can be determined that electrical continuity is obtained from the surface of the conductive portion.

The average fiber diameter of the conductive fibers 24 is preferably 200 nm or less. If the average fiber diameter of the conductive fibers 24 is 200 nm or less, an increase in the haze value of the conductive film 20 can be suppressed, and there is no risk of insufficient light transmission performance. The lower limit of the average fiber diameter of the conductive fibers 24 is more preferably 5 nm or more, 7 nm or more, 10 nm or more, and 15 nm or more in this order from the viewpoint of the conductivity of the conductive portion 23 and disconnection prevention (the larger the value, the more preferable from the viewpoint of disconnection prevention. ), and the upper limit of the average fiber diameter of the conductive fibers 24 is more preferably 180 nm or less, 30 nm or less, 28 nm or less, 25 nm or less, 20 nm or less, or 15 μm or less (the smaller the value, the more preferable from the viewpoint of preventing milkiness). Considering prevention of milkiness, conductivity, and prevention of disconnection, conductive fibers having an average fiber diameter of, for example, 7 nm or more and 15 nm or less are preferably used. From the aspect of mass productivity, the thickness is preferably greater than 15 nm and 25 nm or less.

The fiber diameter of the conductive fiber 24 is determined, for example, by using a transmission electron microscope (TEM) (product name “H-7650”, manufactured by Hitachi High-Technologies Corporation) and taking 50 images at 100,000 to 200,000 times. , the fiber diameters of 100 conductive fibers are actually measured on the imaging screen by software attached to the TEM, and the arithmetic mean value is obtained. When measuring the fiber diameter using the H-7650, the acceleration voltage is "100 kV", the emission current is "10 μA", the focusing lens aperture is "1", the objective lens aperture is "0", and the observation mode is Set "HC" and Spot to "2". The fiber diameter of the conductive fiber can also be measured with a scanning transmission electron microscope (STEM) (product name "S-4800 (TYPE2)", manufactured by Hitachi High-Technologies Corporation). When using STEM, 50 images are taken at 100,000 to 200,000 times, the fiber diameter of 100 conductive fibers is actually measured on the imaging screen by the software attached to STEM, and the arithmetic average value is the conductivity. The fiber diameter of the elastic fiber shall be obtained. When measuring the fiber diameter using the above S-4800 (TYPE2), the signal selection is "TE", the acceleration voltage is "30 kV", the emission current is "10 μA", the probe current is "Norm", and the focus mode is "UHR", condenser lens 1 is "5.0", W. D. to “8 mm” and Tilt to “0°”.

When measuring the fiber diameter of the conductive fibers 24, a measurement sample prepared by the following method is used. Here, since the TEM measurement requires a high magnification, it is important to reduce the concentration of the conductive fiber-containing composition as much as possible so that the conductive fibers do not overlap as much as possible. Specifically, the conductive fiber-containing composition is diluted with water or alcohol in accordance with the dispersion medium of the composition so that the concentration of the conductive fiber is 0.05% by mass or less, or the solid content is 0.2% by mass. It is preferable to dilute to the following. Furthermore, one drop of this diluted conductive fiber-containing composition is dropped on a grid mesh with a carbon support film for TEM or STEM observation, dried at room temperature, and observed under the above conditions to obtain observation image data. Based on this, an arithmetic mean value is obtained. As a grid mesh with a carbon support film, a Cu grid model number "#10-1012 elastic carbon ELS-C10 STEM Cu100P grid specification" is preferable. Suitable for magnification and resistant to organic solvents are preferred. In addition, since the grid mesh alone is too fine to drip, it is preferable to place the grid mesh on a slide glass before dripping.

The fiber diameter can be obtained by actual measurement based on a photograph, or may be calculated by binarization processing based on image data. When actually measuring, you may print a photograph and enlarge it suitably. At that time, the conductive fibers are reflected with a higher density of blackness than the other components. Measurement points are measured with the outside of the contour as the starting point and the ending point. The concentration of the conductive fibers shall be determined by the ratio of the mass of the conductive fibers to the total mass of the conductive fiber-containing composition, and the solid content shall be the components other than the dispersion medium with respect to the total mass of the conductive fiber-containing composition ( conductive fibers, resin components, and other additives).

The average fiber length of the conductive fibers 24 is preferably 1 μm or more. If the average fiber length of the conductive fibers 24 is 1 μm or more, a conductive portion having sufficient conductive performance can be formed, and an increase in haze value and a decrease in light transmission performance can be suppressed. The upper limit of the average fiber length of the conductive fibers 24 may be 500 μm or less, 300 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 20 μm or less, or 15 μm or less. It may be 5 μm or more, 7 μm or more, or 10 μm or more. For example, conductive fibers having an average fiber length of 10 μm or more and 30 μm or less can be preferably used as the conductive fibers 24 .

The fiber diameter of the conductive fiber 24 is measured, for example, by using the SEM function of a scanning electron microscope (SEM) (product name “S-4800 (TYPE2)”, manufactured by Hitachi High-Technologies Corporation) at 5 to 20 million times. Ten images are taken, the fiber lengths of 100 conductive fibers are measured on the imaged screen by the attached software, and the arithmetic mean value of the fiber lengths of the 100 conductive fibers is obtained. When measuring the fiber length using the above S-4800 (TYPE 2), use a 45 ° inclined sample table, signal selection to "SE", acceleration voltage to "3 kV", emission current to "10 μA ~20 μA", SE detector "Mixed", Probe current "Norm", Focus mode "UHR", Condenser lens 1 "5.0", W. D. to “8 mm” and Tilt to “30°”. Since the TE detector is not used during SEM observation, the TE detector must be removed before SEM observation. The S-4800 can select between the STEM function and the SEM function, but the SEM function is used when measuring the fiber length.

When measuring the fiber length of the conductive fibers 24, a measurement sample prepared by the following method is used. First, the conductive fiber-containing composition is applied to the untreated surface of a B5 size polyethylene terephthalate (PET) film having a thickness of 50 μm so that the coating amount is 10 mg / m ² , the dispersion medium is dried, and the PET film surface is coated. Conductive fibers are arranged to produce a conductive film. A size of 10 mm×10 mm is cut out from the central portion of this conductive film. Then, this cut out conductive film is placed on an SEM sample stand (model number “728-45”, manufactured by Nissin EM Co., Ltd., inclined sample stand 45 °, φ 15 mm × 10 mm, made of M4 aluminum) having a 45 ° inclination, It is attached flat to the surface of the table using silver paste. Further, Pt--Pd is sputtered for 20 to 30 seconds to obtain conduction. If there is no suitable sputtered film, the image may be difficult to see, so in that case, adjust accordingly.

The fiber length can be obtained by actual measurement based on a photograph, or may be calculated by binarization processing based on image data. When measuring based on photographs, the same method as above shall be used.

The conductive fibers 24 are preferably at least one type of fiber selected from the group consisting of conductive carbon fibers, metal fibers such as metal nanowires, metal-coated organic fibers, metal-coated inorganic fibers, and carbon nanotubes.

Examples of the conductive carbon fibers include vapor grown carbon fibers (VGCF), carbon nanotubes, wire cups, wire walls, and the like. One or more of these conductive carbon fibers can be used.

Specific examples of the metal elements of the metal fibers include stainless steel, Ag, Cu, Au, Al, Rh, Ir, Co, Zn, Ni, In, Fe, Pd, Pt, Sn and Ti. . One or more of these metal fibers can be used. The metal fibers are preferably metal nanowires having a fiber diameter of 200 nm or less and a fiber length of 1 μm or more.

When silver nanowires are used as metal fibers, silver nanowires can be synthesized by liquid phase reduction of silver salts (eg, silver nitrate) in the presence of polyols (eg, ethylene glycol) and poly(vinylpyrrolidone). be. Mass production of uniformly sized silver nanowires is described, for example, in Xia, Y.; et al. , Chem. Mater. (2002), 14, 4736-4745 and Xia, Y.; et al. , Nanoletters (2003) 3(7), 955-960.

There is no particular limitation on the means for producing metal nanowires, and for example, known means such as a liquid phase method and a vapor phase method can be used. Moreover, the specific production method is not particularly limited, and a known production method can be used. For example, as a method for producing Ag nanowires, Adv. Mater. , 2002, 14, 833-837; Chem. Mater. , 2002, 14, 4736 to 4745, etc., as a method for producing Au nanowires, Japanese Patent Application Laid-Open No. 2006-233252, etc., as a method for producing Cu nanowires, Japanese Patent Application Laid-Open No. 2002-266007, etc., as a method for producing Co nanowires. Japanese Patent Application Laid-Open No. 2004-149871 can be referred to.

The above-mentioned metal fibers can be obtained, for example, by wire drawing or cutting, in which stainless steel, iron, gold, silver, aluminum, nickel, titanium, etc. are thinly and elongated.

Examples of the metal-coated organic fibers include acrylic fibers coated with gold, silver, aluminum, nickel, titanium, or the like. One or more of such metal-coated synthetic fibers can be used.

<Light transmissive resin>
The light-transmitting resin 25 covers the conductive fibers 24 in order to prevent the conductive fibers 24 from detaching from the conductive parts 23 and to improve the durability and scratch resistance of the conductive parts 23. It covers the conductive fibers 24 to such an extent that electrical continuity is obtained from the surface 22A of the conductive portion 23 . Specifically, if some of the conductive fibers are not exposed on the surface of the conductive portion, there is a risk that electrical continuity cannot be obtained from the surface of the conductive portion. It is preferable that the conductive fiber 24 of the portion is covered so as to be exposed from the surface 22A of the conductive portion 23 . In order to cover the conductive fibers 24 with the light transmissive resin 25 so that some of the conductive fibers 24 are exposed on the surface 22A of the conductive portion 23, the thickness of the light transmissive resin 25 may be adjusted, for example. That is, if the thickness of the light-transmitting resin is too thick, all of the conductive fibers are buried in the light-transmitting resin, and some of the conductive fibers are not exposed on the surface of the conductive portion. There is a risk that electrical continuity cannot be obtained from the surface of the On the other hand, if the thickness of the light-transmitting resin is too thin, the conductive fibers may come off from the conductive portion, the durability of the conductive portion may deteriorate, and the scratch resistance may deteriorate. Therefore, it is necessary to adjust the thickness of the light-transmitting resin to an appropriate thickness.

From the above point of view, the thickness of the light transmissive resin 25 is preferably less than 300 nm. The thickness of the light transmissive resin 25 can be measured by the same method as the method for measuring the film thickness of the conductive portion 23 . The upper limit of the film thickness of the light-transmissive resin 25 is more preferably 145 nm or less, 140 nm or less, 120 nm or less, 110 nm or less, 80 nm or less, and 50 nm or less, in that order (the smaller the value, the better). Also, the lower limit of the thickness of the light transmissive resin 25 is preferably 10 nm or more.

The light-transmitting resin 25 is not particularly limited as long as it is a resin having light-transmitting properties. Examples of the light-transmitting resin include polymers of polymerizable compounds, thermoplastic resins, and the like. As the polymerizable compound, the same polymerizable compounds as those described in the column of the resin layer 22 can be used, and therefore the description thereof will be omitted here.

<Reaction inhibitor>
The reaction suppressing agent is for suppressing a decrease in conductivity due to reaction between the conductive fibers 24 and substances in the atmosphere after the application of the composition for a light-transmitting resin. Examples of reaction inhibitors include nitrogen-containing compounds such as benzazole-based compounds, triazole-based compounds, tetrazole-based compounds, isocyanuric acid-based compounds, and aniline-based compounds. Nitrogen-containing compounds used as reaction inhibitors include, for example, 1-aminobenzazole, 5-methylbenzotriazole, 1,2,3-benzotriazole, 1-methyl-1H-tetrazol-5-amine, and DL-α. -tocopherol, 1-octadecanethiol, 2-mercapto-5-(trifluoromethyl)pyridine, diallyl isocyanurate, diallylpropyl isocyanurate, 6-anilino-1,3,5-triazine-2,4-dithiol, thiocyanuric acid , 3,5-dimethyl-1H-1,2,4-triazole, 4-(1,2,4-triazol-1-ylmethyl)aniline, 6-(dibutylamino)-1,3,5-triazine-2 ,4-dithiol, 4-(1,2,4-triazol-1-yl)aniline, 2-methylthio-benzothiazole, 1-phenyl-5-mercapto-1H-tetrazole, 5-mercapto-1-methyltetrazole, 5-(methylthio)-1H-tetrazole, 5-amino-1H-tetrazole, 1-(2-dimethylaminoethyl)-5-mercaptotetrazole, 1-(2-dimethylaminoethyl)-5-mercaptotetrazole, 1- (4-Hydroxyphenyl)-5-mercapto-1H-tetrazole, 3-amino-5-mercapto-1,2,4-triazole, 3,5-diamino-1,2,4-triazole.

The content of the reaction inhibitor in the conductive portion 23 is preferably 0.01% by mass or more and 10% by mass or less. If the content of the reaction inhibitor is less than 0.01% by mass, the conductive fibers may react with substances in the atmosphere, resulting in a decrease in conductivity. In addition, the reaction inhibitor deactivates the surface of the conductive fiber by reacting with the surface of the conductive fiber, thereby creating a state in which the conductive fiber hardly reacts with substances in the atmosphere. content exceeds 10% by mass, the reaction with the reaction inhibitor in the conductive fiber may proceed not only to the surface of the conductive fiber but also to the inside, resulting in a decrease in conductivity.

<<Protective Film>>
The protective film 30 is detachably attached to the surface 23A of the conductive portion 23 . The protective film 30 has a function of suppressing sticking between the films when the conductive film 20 is wound and a function of preventing scratches.

The thickness of the protective film 30 is preferably 25 μm or more and 150 μm or less. If the thickness of the protective film 30 is 25 μm or more, the function of protecting the conductive film can be sufficiently exhibited. Detachment of the film 30 can be suppressed. The thickness of the protective film 30 can be measured by the same method as the thickness of the light transmissive substrate 21 . The lower limit of the thickness of the protective film 30 is preferably 50 μm or more, and the upper limit is preferably 125 μm or less, from the viewpoint of suppressing folding during transport of the film.

The protective film 30 can be composed of a resin base material and an adhesive layer provided on one side of the resin base material. The resin constituting the resin base material of the protective film 30 is not particularly limited, but examples thereof include polyester-based resins such as polyethylene terephthalate resin, polycarbonate-based resins, and polyamide-based resins. For example, when the light-transmitting base material 21 is a base material made of a polyester-based resin, the resin base material is preferably made of a polyester-based resin from the viewpoint of further suppressing curling. A self-adhesive resin film may be used as the protective film.

<<Method for producing conductive film with protective film>>
The conductive film 10 with a protective film can be produced, for example, as follows. First, as shown in FIG. 4A, the light-transmitting substrate 21 is neutralized. It should be noted that the crack-like streak unevenness can be further suppressed by removing the static electricity from the light-transmitting base material 21, but the static elimination is not essential. Moreover, although the charge removal is performed before the resin layer 22 is formed, it may be performed after the resin layer 22 is formed. However, it is preferable to perform static elimination before the resin layer 22 is formed, because it is possible to suppress an increase in the amount of charge during the formation of the resin layer 22 and to facilitate adjustment of the static elimination.

Examples of static eliminators for static elimination include a method of static elimination using a voltage application type static eliminator, a self-discharge type static eliminator, a soft X-ray static eliminator, and an ultraviolet static eliminator. In particular, the amount of ions generated is large and controllable, and the amount of charge on the surface of the light-transmitting substrate can be stably controlled over a long section in the longitudinal direction of the light-transmitting substrate. It is preferable to remove static electricity using a static eliminator.

The charge amount of the light-transmissive substrate 21 after static elimination is preferably -1.5 kV or more and 1.5 kV or less from the viewpoint of suppressing crack-like stripe unevenness. The charge amount of the light-transmissive substrate 21 after static elimination can be measured using a surface potential meter (product name “KSD-1000” manufactured by Kasuga Denki Co., Ltd.).

After static elimination, as shown in FIG. 4B, the resin layer composition is applied to the surface of the underlying layer 21D of the light-transmitting substrate 21 and dried to form a coating film 26 of the resin layer composition. Form.

Although the resin layer composition contains a polymerizable compound, the inorganic particles, the leveling agent, the solvent, and the polymerization initiator may be added as necessary. Further, the resin layer composition may contain conventionally known dispersants, surfactants, and silane coupling agents according to the purpose of increasing the hardness of the resin layer, suppressing curing shrinkage, or controlling the refractive index. , thickeners, anti-coloring agents, coloring agents (pigments, dyes), antifoaming agents, flame retardants, UV absorbers, adhesion promoters, polymerization inhibitors, antioxidants, surface modifiers, lubricants, etc. You may have

<Solvent>
Examples of solvents include alcohols (methanol, ethanol, propanol, isopropanol, n-butanol, s-butanol, t-butanol, benzyl alcohol, PGME, ethylene glycol, etc.), ketones (acetone, methyl ethyl ketone (MEK), cyclohexanone , methyl isobutyl ketone, diacetone alcohol, cycloheptanone, diethyl ketone, etc.), ethers (1,4-dioxane, dioxolane, diisopropyl ether dioxane, tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic Hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated carbons (dichloromethane, dichloroethane, etc.), esters (methyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, lactic acid ethyl, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, butyl cellosolve, etc.), cellosolve acetates, sulfoxides (dimethyl sulfoxide, etc.), amides (dimethylformamide, dimethylacetamide, etc.), or mixtures thereof.

<Polymerization initiator>
A polymerization initiator is a component that is decomposed by light or heat to generate radicals or ionic species to initiate or advance polymerization (crosslinking) of a polymerizable compound. Polymerization initiators used in the resin layer composition include photopolymerization initiators (e.g., photoradical polymerization initiators, photocationic polymerization initiators, photoanion polymerization initiators) and thermal polymerization initiators (e.g., thermal radical polymerization initiators). thermal cationic polymerization initiators, thermal anionic polymerization initiators), or mixtures thereof.

The content of the polymerization initiator in the resin layer composition is preferably 0.5 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the polymerizable compound. By setting the content of the polymerization initiator within this range, the hard coat performance can be sufficiently maintained, and curing inhibition can be suppressed.

Examples of the method for applying the resin layer composition include known coating methods such as spin coating, dipping, spraying, slide coating, bar coating, roll coating, gravure coating, and die coating.

Next, as shown in FIG. 4(C), the coating film 26 is irradiated with ionizing radiation such as ultraviolet rays or heated to polymerize (crosslink) the polymerizable compound, thereby curing the coating film 26 to obtain a resin. A layer 22 is formed.

When ultraviolet rays are used as the ionizing radiation for curing the coating film 26, ultraviolet rays emitted from ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, carbon arcs, xenon arcs, metal halide lamps, etc. can be used. As the wavelength of ultraviolet rays, a wavelength range of 190 to 380 nm can be used. Specific examples of the electron beam source include various electron beam accelerators such as Cockcroftwald type, Vandegraft type, resonance transformer type, insulating core transformer type, linear type, dynamitron type, and high frequency type.

After forming the resin layer 22, a conductive fiber-containing composition containing conductive fibers 24 and an organic dispersion medium is applied to the surface (untreated surface) of the light transmissive substrate 21 on which the underlying layer 21D is not formed. and dried to arrange a plurality of conductive fibers 24 on the untreated surface of the light transmissive substrate 21 as shown in FIG. 5(A). The organic dispersion medium may contain less than 10% by mass of water. In addition to the conductive fibers 24 and the organic dispersion medium, the conductive fiber-containing composition may contain a resin component made of a thermoplastic resin or a polymerizable compound. However, if the resin content in the conductive fiber-containing composition is too high, the resin will enter between the conductive fibers and the conduction of the conductive part will deteriorate, so the resin content should be adjusted. There is a need to. As used herein, the term “resin component” refers to a resin (however, it is used to prevent self-welding of the conductive fibers covering the conductive fibers and reaction with substances in the atmosphere, etc., so that the conductive fibers are made conductive during synthesis. It does not include the resin (for example, polyvinylpyrrolidone, etc.) that constitutes the organic protective layer formed around the fiber), and also includes components such as polymerizable compounds that can be polymerized to form resins. Further, the resin content in the conductive fiber-containing composition constitutes a part of the light transmissive resin 25 after the conductive portion 23 is formed.

Although the organic dispersion medium is not particularly limited, it is preferably a hydrophilic organic dispersion medium. Examples of organic dispersion media include saturated hydrocarbons such as hexane; aromatic hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, propanol and butanol; acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone. , Ketones such as diisobutyl ketone; Esters such as ethyl acetate and butyl acetate; Ethers such as tetrahydrofuran, dioxane and diethyl ether; N,N-dimethylformamide, N-methylpyrrolidone (NMP), N,N-dimethylacetamide amides such as ethylene chloride; and halogenated hydrocarbons such as ethylene chloride and chlorobenzene. Among these, alcohols are preferable from the viewpoint of the stability of the conductive fiber-containing composition.

Thermoplastic resins that may be contained in the conductive fiber-containing composition include acrylic resins; polyester resins such as polyethylene terephthalate; aromatic resins such as polystyrene, polyvinyltoluene, polyvinylxylene, polyimide, polyamide, and polyamideimide. Resin; Polyurethane resin; Epoxy resin; Polyolefin resin; Acrylonitrile-butadiene-styrene copolymer (ABS); Cellulose resin; system resin and the like.

Examples of the polymerizable compound that may be contained in the conductive fiber-containing composition include the same polymerizable compounds as those described in the column of the resin layer 22, and thus the description thereof is omitted here.

After arranging a plurality of conductive fibers 24 on the untreated surface of the light-transmitting substrate 21, a light-transmitting resin composition containing a polymerizable compound and a solvent is applied, dried, and dried, as shown in FIG. 5(B). A coating film 27 of a light-transmissive resin composition is formed as shown in FIG. The composition for a light-transmitting resin contains a polymerizable compound and a solvent, but may also contain a polymerization initiator and the above reaction inhibitor, if necessary. Here, it is possible to add the reaction inhibitor to the conductive fiber-containing composition, but if the reaction inhibitor is added to the conductive fiber-containing composition, the conductive Since the surface of the optical fiber may be coated with the reaction inhibitor and the conductivity may be deteriorated, it is preferable to add the reaction inhibitor to the composition for the light-transmitting resin.

Next, as shown in FIG. 6A, the coating film 27 is irradiated with ionizing radiation such as ultraviolet rays to polymerize (crosslink) the polymerizable compound, thereby curing the coating film 27 and forming a light-transmitting resin. 25 is formed to form the conductive portion 23 .

After forming the conductive portion 23, as shown in FIG. 6B, a protective film 30 is detachably attached to the surface 23A of the conductive portion 23. Next, as shown in FIG. Thereby, the conductive film 10 with a protective film is obtained.

The reason why crack-like streak unevenness occurs when the conductive portion is formed of conductive fibers is considered to be as follows. First, a roll-shaped light-transmitting base material is unwound to form a resin layer or the like, but the light-transmitting base material is positively charged at that time. Here, in the roll state, the amount of charge when the light-transmitting substrate is unwound tends to be greater when different materials are in contact than when the same type of material is in contact. That is, in the case where the light-transmitting base material has the base layer only on one side, the light-transmitting base material is in contact with the base layer, which is a different material, when it is wound into a roll. When the base material is unwound, the charge amount is greater than when the base material does not have the underlayer. On the other hand, when the positive charges of the unrolled light-transmitting substrate are removed by the static eliminator, the positive charges existing on the surface of the light-transmitting substrate are removed, but the positive charges existing inside are removed. Static electricity is not eliminated. Therefore, if the conductive portion is formed before forming the resin layer, the positive charges remaining inside the light-transmitting base material move toward the conductive portion, and the conductive portion is affected by the positive charge. Due to the influence of the electric charge, the distribution of the conductive fibers is not uniform, resulting in formation of sparse portions and dense portions of the conductive fibers. Then, it is considered that the boundary between the sparse portion and the dense portion of the conductive fibers is confirmed as crack-like streak unevenness. On the other hand, in the present embodiment, the resin layer 22 is formed on the light-transmissive base material 21 before the conductive part 23 is formed. Move to the layer 22 side. For this reason, even if the conductive portion 23 is formed, it is less likely to be affected by positive charges, and variations in the distribution of the conductive fibers 24 in the planar direction of the conductive portion 23 can be suppressed. Dense parts are less likely to be formed. Thereby, crack-like streak unevenness can be suppressed.

According to the present embodiment, since the light-transmissive substrate 21 is neutralized before the formation of the conductive portion 23, particularly before the formation of the resin layer 22, the static electricity present on the first surface 21A of the light-transmissive substrate 21 is eliminated. The positive charge can be eliminated, thereby further suppressing crack-like streak unevenness.

In general, the back surface of the protective film (the surface opposite to the surface of the object to which the protective film is attached) has large irregularities in consideration of winding properties. Therefore, the back surface of the protective film 30 (the surface opposite to the surface attached to the surface 23A of the conductive portion 23) is also more uneven than the surface 23A of the conductive portion 23. As shown in FIG. The size of unevenness of the protective film can be measured, for example, by arithmetic mean roughness (Ra). According to the present embodiment, since the protective film 30 is detachably attached to the surface 23A of the conductive portion 23 in the conductive film 20, the adhesion between the films 10 when the conductive film 10 with the protective film is rolled up is can suppress sticking.

In addition, although the thickness of the conductive film 20 is thin, since the protective film 30 is detachably attached to the surface 20A of the conductive film 20, it can be handled with the protective film 30 attached. Easy to handle.

Since the surface of the light-transmitting base material has fine irregularities, the external haze may become high. Since the layer 22 is provided, the resin layer 22 can fill minute irregularities present on the second surface 21B of the light transmissive base material 21 . As a result, the external haze value can be lowered. Moreover, when the light-transmitting substrate is heated, the oligomer component is precipitated from the light-transmitting substrate, the external haze value increases, and the transparency may be lost. In contrast, in the present embodiment, the resin layer 22 is formed on the second surface 21B of the light-transmitting substrate 21, so precipitation of oligomer components from the light-transmitting substrate 21 can be suppressed. can. Thereby, even when the conductive film 20 is heated, the haze value of the conductive film 20 can be suppressed from increasing, and the transparency can be ensured.

According to this embodiment, since the conductive fibers 24 are used, unlike ITO, it is possible to provide the conductive film 20 that is hard to crack even when bent. Therefore, it is also possible to use the conductive film 20 by incorporating it into a foldable image display device. The foldable image display device may comprise organic light emitting diodes (OLEDs) as display elements.

EXAMPLES In order to describe the present invention in detail, examples are given below, but the present invention is not limited to these descriptions.

<Preparation of composition for hard coat layer>
First, a hard coat layer composition 1 was obtained by blending each component so as to obtain the composition shown below.
(Composition 1 for hard coat layer)
・ A mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (product name “KAYARAD-PET-30”, manufactured by Nippon Kayaku Co., Ltd.): 30 parts by mass ・ Polymerization initiator (product name “Irgacure 184”, manufactured by BASF Japan Co., Ltd. ): 1.5 parts by mass Methyl ethyl ketone (MEK): 50 parts by mass Cyclohexanone: 18.5 parts by mass

<Preparation of composition containing silver nanowires>
(Silver nanowire-containing composition 1)
Ethylene glycol (EG) is used as a reducing agent, and polyvinylpyrrolidone (PVP: average molecular weight 1,300,000, manufactured by Aldrich) is used as an organic protective agent, and grains are formed by separating the nucleation step and the grain growth step shown below. was performed to prepare a silver nanowire-containing composition.

1. Nucleation step While stirring 100 mL of the EG solution maintained at 160°C in a reaction vessel, 2.0 mL of an EG solution of silver nitrate (silver nitrate concentration: 1.0 mol/L) was added at a constant flow rate over 1 minute. . Thereafter, the silver ions were reduced while the temperature was maintained at 160° C. for 10 minutes to form silver core particles. The reaction solution exhibited a yellow color due to surface plasmon absorption of nano-sized silver fine particles, confirming that silver ions were reduced to form silver fine particles (nuclear particles). Subsequently, 10.0 mL of an EG solution of PVP (PVP concentration: 3.0×10 ⁻¹ mol/L) was added at a constant flow rate over 10 minutes.

2. Particle growth step After the nucleation step, the reaction solution containing the nucleus particles was kept at 160°C with stirring, and added with 100 mL of an EG solution of silver nitrate (silver nitrate concentration: 1.0 × 10 ^-1 mol/L). , 100 mL of an EG solution of PVP (PVP concentration: 3.0×10 ⁻¹ mol/L) was added at a constant flow rate over 120 minutes using the double-jet method. In this particle growth step, the reaction solution was sampled every 30 minutes and observed with an electron microscope. No new fine particle formation was observed in the process. When the fiber diameter and fiber length of the finally obtained silver nanowires were measured, the fiber diameter of the silver nanowires was 30 nm and the fiber length was 15 μm.

3. Desalting Water Washing Step After cooling the reaction solution after the particle growth step to room temperature, desalting water washing treatment was performed using an ultrafiltration membrane with a molecular weight cut off of 0.2 μm, and the solvent was replaced with ethanol. Finally, the liquid volume was concentrated to 100 mL to prepare a silver nanowire dispersion liquid. Finally, it was diluted with ethanol so that the concentration of silver nanowires was 0.1% by mass, and a composition 1 containing silver nanowires was obtained.

When the fiber diameter and fiber length of the silver nanowires in the silver nanowire-containing composition 1 were measured, the fiber diameter of the silver nanowires was 30 nm and the fiber length was 15 μm. The fiber diameter of the silver nanowires is measured using a transmission electron microscope (TEM) (product name "H-7650", manufactured by Hitachi High-Technologies Corporation), 50 images are taken at 100,000 to 200,000 times, and the attached TEM The fiber diameter of 100 conductive fibers was actually measured on the imaging screen by software, and the arithmetic mean value was obtained. When measuring the fiber diameter, the acceleration voltage is "100 kV", the emission current is "10 μA", the focusing lens aperture is "1", the objective lens aperture is "0", the observation mode is "HC", and the spot is " 2”. In addition, the fiber length of the silver nanowires was measured using a scanning electron microscope (SEM) (product name “S-4800 (TYPE2)”, manufactured by Hitachi High-Technologies Corporation) at 500 to 20 million times at 100 silver nanowires. was measured, and the arithmetic mean value of the fiber lengths of the 100 silver nanowires was obtained. When measuring the fiber length, the signal selection was set to "SE", the acceleration voltage was set to "3 kV", the emission current was set to "10 μA", and the SE detector was set to "mixed". The fiber length of the silver nanowires was obtained by using the SEM function of a scanning electron microscope (SEM) (product name “S-4800 (TYPE2)”, manufactured by Hitachi High-Technologies Corporation) and taking 10 images at 500 to 20 million times. , the fiber length of 100 silver nanowires was measured on the imaging screen by the attached software, and the arithmetic mean value of the fiber lengths of the 100 silver nanowires was obtained. When measuring the fiber length, a 45° inclined sample table was used, signal selection was set to "SE", acceleration voltage was set to "3 kV", emission current was set to "10 μA to 20 μA", and the SE detector was set to "mixed ”, probe current “Norm”, focus mode “UHR”, condenser lens 1 “5.0”, W. D. was set to "8 mm" and Tilt was set to "30°". Note that the TE detector was removed in advance. When measuring the fiber diameter of silver nanowires, a measurement sample prepared by the following method was used. First, silver nanowire-containing composition 1 was diluted with ethanol to a concentration of silver nanowires of 0.05% by mass or less in accordance with the dispersion medium of the composition. Furthermore, one drop of this diluted silver nanowire-containing composition 1 was dropped on a grid mesh with a carbon support film for TEM or STEM observation (Cu grid model number “#10-1012 elastic carbon ELS-C10 STEM Cu100P grid specification”). , dried at room temperature, observed under the above conditions, and used as observed image data. Based on this, an arithmetic mean value was obtained. When measuring the fiber length of silver nanowires, a measurement sample prepared by the following method was used. First, the silver nanowire-containing composition 1 was applied to the untreated surface of a B5 size polyethylene terephthalate (PET) film having a thickness of 50 μm so that the coating amount was 10 mg / m ² , the dispersion medium was dried, and the PET film surface was coated. A conductive film was produced by arranging the conductive fibers. A size of 10 mm×10 mm was cut from the central portion of this conductive film. Then, this cut-out conductive film is placed on a SEM sample stage (model number “728-45”, manufactured by Nisshin EM Co., Ltd., inclined sample stage 45°, φ15 mm × 10 mm, made of M4 aluminum) having a 45° inclination. It was attached flat to the surface of the table using paste. Further, Pt--Pd was sputtered for 20 to 30 seconds to obtain conduction. The fiber diameter and fiber length of silver nanowires described below were also obtained in the same manner.

(Silver nanowire-containing composition 2)
A silver nanowire-containing composition 2 was obtained in the same manner as the silver nanowire-containing composition 1, except that the concentration of the silver nanowires was 0.2% by mass.

<Preparation of composition for light-transmitting resin>
A composition 1 for a light-transmitting resin was obtained by blending each component so as to have the composition shown below.
(Composition 1 for light-transmitting resin)
・ A mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (product name “KAYARAD-PET-30”, manufactured by Nippon Kayaku Co., Ltd.): 5 parts by mass ・ Polymerization initiator (product name “Irgacure 184”, manufactured by BASF Japan Co., Ltd. ): 0.25 parts by mass Methyl ethyl ketone (MEK): 70 parts by mass Cyclohexanone: 24.75 parts by mass

<Example 1>
First, a 50 μm-thick polyethylene terephthalate film (product name “Cosmoshine A4100”, manufactured by Toyobo Co., Ltd.) having an underlayer on only one side as a light-transmitting substrate was prepared, and the surface of the underlayer of the polyethylene terephthalate film was coated with , the hard coat layer composition 1 was applied to form a coating film. Next, dry air at 50°C is passed through the formed coating film at a flow rate of 0.5 m/s for 15 seconds, and then dry air at 70°C is passed at a flow rate of 10 m/s for 30 seconds to dry. A hard coat layer having a film thickness of 2 μm was formed by evaporating the solvent in the coating film and curing the coating film by irradiating the coating film with ultraviolet rays so that the integrated light amount was 100 mJ/cm ² .

After forming the hard coat layer, the silver nanowire-containing composition 1 was applied to the untreated surface of the polyethylene terephthalate film opposite to the underlayer side so that the coating amount was 10 mg/m ² . Then, dry air at 50°C was passed through the applied silver nanowire-containing composition 1 at a flow rate of 0.5 m/s for 15 seconds, and then dry air at 70°C was passed at a flow rate of 10 m/s for 30 seconds. By circulating and evaporating the dispersion medium in the composition 1 containing silver nanowires, a plurality of silver nanowires were arranged on the untreated surface.

Next, the composition 1 for a light-transmitting resin was applied so as to cover the silver nanowires to form a coating film. Then, dry air at 50 ° C. is passed through the formed coating film at a flow rate of 0.5 m / s for 15 seconds, and then dry air at 70 ° C. is passed at a flow rate of 10 m / s for 30 seconds to dry. By evaporating the solvent in the coating film and curing the coating film by irradiating the coating film with ultraviolet rays so that the integrated light amount becomes 100 mJ / cm ² , a light-transmitting resin with a film thickness of 100 nm is formed. A conductive portion with a film thickness of 100 nm consisting of silver nanowires arranged in a transparent resin and a transparent resin was obtained.

After forming the conductive part, a protective film that is a polyethylene film with a thickness of 50 μm (product name “PAC3-50THK”, manufactured by Sanei Kaken Co., Ltd.) is attached to the surface of the conductive part so that it can be peeled off. got the film.

The film thickness of the conductive portion according to Example 1 was obtained by randomly measuring the thickness of 10 locations from a cross-sectional photograph of the conductive portion taken using a scanning transmission electron microscope (STEM), and calculating the thickness of the measured 10 locations. Average value. Specific cross-sectional photographs were taken by the following method. First, a sample for cross-sectional observation was produced from the conductive film. Specifically, a conductive film cut into a size of 2 mm×5 mm was placed in a silicone-based embedding plate, an epoxy-based resin was poured into the plate, and the entire conductive film was embedded in the resin. After that, the embedding resin was allowed to stand at 65° C. for 12 hours or longer to cure. Then, using an ultramicrotome (product name: "Ultramicrotome EM UC7", manufactured by Leica Microsystems), an ultrathin section was prepared by setting the feed-out thickness to 100 nm. The produced ultra-thin section was collected with a mesh (150) with a collodion membrane and used as a sample for STEM. After that, using a scanning transmission electron microscope (STEM) (product name “S-4800 (TYPE2)”, manufactured by Hitachi High-Technologies Corporation), a cross-sectional photograph of the STEM sample was taken. When taking this cross-sectional photograph, the detector (selection signal) was set to "TE," the acceleration voltage to 30 kV, and the emission to "10 .mu.A." Magnification was appropriately adjusted between 5,000 and 200,000 times while adjusting the focus and observing whether each layer could be distinguished in terms of contrast and brightness. A preferable magnification is 10,000 to 50,000 times, more preferably 25,000 to 40,000 times. If the magnification is increased too much, the pixels at the layer interface become rough and difficult to understand, so it is better not to increase the magnification too much in film thickness measurement. When taking a cross-sectional photograph, the aperture is set to 3 for the beam monitor diaphragm, the objective lens diaphragm is set to 3, and the W.F. D. was set to 8 mm. The film thickness of the conductive portion was measured by this method not only in Example 1 but also in all of the subsequent Examples and Comparative Examples.

<Example 2>
A conductive film with a protective film was obtained in the same manner as in Example 1, except that the silver nanowire-containing composition 2 was used instead of the silver nanowire-containing composition 1 to form the conductive portion.

<Example 3>
In Example 3, instead of the polyethylene film (product name “PAC3-50THK”, manufactured by Sanei Kaken Co., Ltd.), a polyethylene terephthalate film having a thickness of 47 μm (product name “NSA33T”, Sanei Co., Ltd.) was applied to the surface of the conductive part. A conductive film with a protective film was obtained in the same manner as in Example 1, except that a protective film made by Kaken) was detachably attached.

<Example 4>
In Example 4, a conductive film with a protective film was obtained in the same manner as in Example 1, except that the polyethylene terephthalate film was neutralized before forming the hard coat layer. Static elimination was performed using a voltage application type static eliminator (product name: "nano Type Static Eliminator", manufactured by Wedge Co., Ltd.). The static eliminator was set so that the applied voltage was adjusted so that the value of a surface potential meter (product name “KSD-1000” manufactured by Kasuga Denki Co., Ltd.) installed after the formation of the hard coat layer was ±0 kv.

<Comparative Example 1>
First, a 50 μm thick polyethylene terephthalate film (product name “Cosmoshine A4100” manufactured by Toyobo Co., Ltd.) having a 100 nm thick underlayer on only one side was prepared, and the side opposite to the underlayer side of the polyethylene terephthalate film was prepared. The silver nanowire-containing composition 1 was applied to the untreated surface of the side so that the coating amount was 10 mg/m ² . Then, dry air at 50°C was passed through the applied silver nanowire-containing composition 1 at a flow rate of 0.5 m/s for 15 seconds, and then dry air at 70°C was passed at a flow rate of 10 m/s for 30 seconds. By circulating and evaporating the dispersion medium in the composition 1 containing silver nanowires, a plurality of silver nanowires were arranged on the untreated surface.

Next, the composition 1 for a light-transmitting resin was applied so as to cover the silver nanowires to form a coating film. Then, dry air at 50 ° C. is passed through the formed coating film at a flow rate of 0.5 m / s for 15 seconds, and then dry air at 70 ° C. is passed at a flow rate of 10 m / s for 30 seconds to dry. By evaporating the solvent in the coating film and curing the coating film by irradiating the coating film with ultraviolet rays so that the integrated light amount becomes 100 mJ / cm ² , a light-transmitting resin with a film thickness of 100 nm is formed. A conductive portion with a film thickness of 100 nm consisting of silver nanowires arranged in a transparent resin and a transparent resin was obtained.

After forming the conductive portion, the hard coat layer composition 1 was applied to the surface of the underlayer of the light-transmitting substrate to form a coating film. Next, dry air at 50°C is passed through the formed coating film at a flow rate of 0.5 m/s for 15 seconds, and then dry air at 70°C is passed at a flow rate of 10 m/s for 30 seconds to dry. By evaporating the solvent in the coating film, the coating film is cured by irradiating the coating film with ultraviolet light so that the integrated light amount becomes 100 mJ / cm ² , thereby forming a hard coat layer with a thickness of 2 μm and making it conductive. got the film.

<Comparative Example 2>
In Comparative Example 2, a conductive film was obtained in the same manner as in Comparative Example 1, except that the silver nanowire-containing composition 2 was used instead of the silver nanowire-containing composition 1 to form the conductive portion.

<Comparative Example 3>
In Comparative Example 3, a conductive film with a protective film was obtained in the same manner as in Comparative Example 1, except that the polyethylene terephthalate film was neutralized before forming the conductive portion. Static elimination was performed using a voltage application type static eliminator (product name: "nano Type Static Eliminator", manufactured by Wedge Co., Ltd.).

<Appearance evaluation>
From the conductive film with a protective film according to Examples 1 to 4, the protective film was peeled off to form a single conductive film, and the surface of the conductive portion was observed. It was evaluated whether or not Also, in the conductive films according to Comparative Examples 1 to 3, the surface of the conductive portion was observed to evaluate whether crack-like streak unevenness was present in the conductive portion in the same manner as described above. Specifically, first, a conductive film with a size of 1 m × 1 m is visually observed, and if defects such as cracked streaks are confirmed, a 10 cm × 10 cm film containing this defect is removed from the conductive film. A size sample was cut out. Then, the surface of the conductive portion in this sample was observed with an optical microscope. The evaluation criteria were as follows.
◯: No crack-like streak unevenness was observed in the conductive portion, or was slightly observed, but it was at a level of practically no problem.
x: Crack-like streak unevenness was clearly observed in the conductive portion.

<Sticking prevention>
The sticking prevention properties of the conductive films with protective films according to Examples 1 to 4 and the conductive films according to Comparative Examples 1 to 3 were evaluated. Specifically, in the conductive films with protective films according to Examples 1 to 4, first, two conductive films with protective films cut into a size of 20 mm long × 20 mm wide were combined with a hard coat layer and protective film. The films were superimposed so that they were in contact with each other to obtain an evaluation sample. In addition, in the conductive films according to Comparative Examples 1 to 3, two conductive films cut into a size of 20 mm long × 20 mm wide were superimposed so that the hard coat layer and the conductive part were in contact with each other, and the evaluation samples were obtained. and Then, the evaluation sample was left for 12 hours with a load of 1500 N applied using a permanent deformation tester (product name “CO-201”, manufactured by Tester Sangyo Co., Ltd.). After that, the evaluation sample was removed from the permanent deformation tester, and it was evaluated whether or not the films constituting the evaluation sample stuck to each other. The evaluation criteria were as follows.
◯: Sticking of the film was not confirmed.
x: Sticking of the film was confirmed.

<Surface resistance value measurement>
From the conductive films with protective films according to Examples 1 to 4, the protective film was peeled off to obtain the conductive film alone, and the surface resistance value of the conductive portion was measured. Also, in the conductive films according to Comparative Examples 1 to 3, the surface resistance value of the conductive portion was measured. Specifically, in the conductive film, a contact-type resistivity meter (product name “Loresta AX MCP-T370 type”, compliant with JIS K7194: 1994 (resistivity test method by four-probe method for conductive plastics), The surface resistance value of the conductive portion was measured using a terminal shape: ASP probe manufactured by Mitsubishi Chemical Analytech Co., Ltd. The surface resistance value is measured by a contact-type resistivity meter. A conductive film cut into a size of 80 mm long x 50 mm wide is placed on a flat glass plate with the conductive part side facing up, and the conductive film is in a uniform flat state. , the ASP probe was placed in the center of the conductive portion, and all the electrode pins were uniformly pressed against the conductive portion. In the measurement with the contact-type resistivity meter, Ω/□, which is the mode for measuring sheet resistance, was selected. After that, I pressed the start button, held it, and got the measurement result. The surface resistance value was measured at three points in the center of the conductive film, and the surface resistance value was the arithmetic mean value of the surface resistance values at the three points. The surface resistance value was measured under an environment of 23° C. and a relative humidity of 55%.

<Flexibility>
From the conductive films with protective films according to Examples 1 to 4, the protective films were peeled off, and the conductive films alone were subjected to a continuous folding test to evaluate the flexibility. Specifically, a rectangular sample of 125 mm long×50 mm wide was cut out from the conductive film before the continuous folding test. After cutting out the sample from the conductive film, a silver paste (product name “DW-520H-14”, manufactured by Toyobo Co., Ltd.) is applied to a portion of 10 mm long x 50 mm wide at each end of the conductive portion in the longitudinal direction of each sample. was applied and heated at 130° C. for 30 minutes to form a hardened silver paste on both ends of the conductive portion. The distance between both end portions of the conductive portion was fixed at 105 mm. Then, the electrical resistance value of the conductive portion of the sample before the continuous folding test was measured using a tester (product name “Digital MΩ Hitester 3454-11” manufactured by Hioki Electric Co., Ltd.). Specifically, the Digital MΩ Hitester 3454-11 has two probe terminals (a red probe terminal and a black probe terminal, both of which are pin-shaped). The electrical resistance value was measured by contacting the hardened silver paste and bringing the black probe terminal into contact with the hardened silver paste provided at the other end. After that, the short side (50 mm) side of the sample was fixed to an endurance tester (product name "DLDMLH-FS", manufactured by Yuasa System Co., Ltd.) with a fixing part, and faced as shown in Fig. 3 (C). The sample is attached so that the minimum distance between the two sides is 4 mm (the outer diameter of the bent part is 4 mm), and the sample is folded 180° repeatedly 100,000 times so that the hard coat layer side is inside (the conductive part is outside). A sequential folding test was performed. After conducting the continuous folding test, the electrical resistance of the conductive portion was measured in the sample after the continuous folding test in the same manner as the sample before the continuous folding test. Then, the electrical resistance value ratio (the electrical resistance of the conductive portion of the sample after the continuous folding test), which is the ratio of the electrical resistance value of the conductive portion of the sample after the continuous folding test to the electrical resistance value of the conductive portion of the sample before the continuous folding test value/electric resistance value of the conductive portion of the sample before the continuous folding test) was obtained. And the following criteria evaluated the result of the continuous folding test as flexibility. In addition, the electrical resistance value ratio was taken as the arithmetic mean value of the value obtained by measuring 3 times.
A: The electric resistance value ratio was 1.5 or less.
◯: The electrical resistance value ratio was more than 1.5 and 3 or less.
x: The electrical resistance value ratio exceeded 3.

<Total light transmittance measurement>
A haze meter (product name "HM-150", manufactured by Murakami Color Research Laboratory) was used to peel off the protective film from the conductive film with a protective film according to Examples 1 to 4 and obtain a single conductive film. Then, the total light transmittance was measured according to JIS K7361:1997. The total light transmittance is a value when measured on the entire conductive film, and after cutting into a size of 50 mm × 100 mm, the conductive part side is non-curling, wrinkled, fingerprints, dust, etc. It was installed so as to be on the light source side, and the total light transmittance was taken as the arithmetic mean value of the values obtained by measuring three times.

<Haze measurement>
From the conductive film with a protective film according to Examples 1 to 4, the protective film and the protective film were peeled off, and the conductive film alone was measured with a haze meter (product name "HM-150", manufactured by Murakami Color Research Laboratory ) was used to measure the haze value (total haze value) of the conductive film according to JIS K7136:2000. The haze value is a value when measured on the entire conductive film, and after cutting into a size of 50 mm × 100 mm, the conductive part side is the non-light source side in a state where there are no curls, wrinkles, fingerprints, dust, etc. and the haze value was the arithmetic mean value of the values obtained by measuring three times.

The results are shown in Tables 1 and 2 below.

In the conductive films according to Comparative Examples 1 to 3, since the hard coat layer was formed after the formation of the conductive portion, crack-like streak unevenness was clearly observed. In addition, the conductive films according to Comparative Examples 1 to 3 were inferior in windability because they did not have a protective film. On the other hand, in the conductive films with a protective film according to Examples 1 to 4, since the hard coat layer was formed before the formation of the conductive portion, crack-like streak unevenness was not observed, or was slightly observed. The level was at a practically acceptable level. In addition, the conductive films with protective films according to Examples 1 to 4 were excellent in windability due to the provision of the protective film.

When the Martens hardness of the hard coat layer and the light-transmitting substrate in the conductive films of Examples 1 to 4 was measured, the hard coat layer had higher Martens hardness than the light-transmitting substrate. The Martens hardness of the hard coat layer was measured using a microhardness tester (product name “PICODENTOR HM500”, manufactured by Fisher Instruments, ISO14577-1, ASTM E2546 compliant) measurement sample. Specifically, first, a block is prepared by embedding a conductive film cut into 1 mm × 10 mm with an embedding resin, and from this block, a uniform section with a thickness of 70 nm or more and 100 nm without holes is produced by a general section preparation method. The following sections were cut. "Ultramicrotome EM UC7" (Leica Microsystems, Inc.) was used to prepare the sections. Then, the remaining block from which uniform sections without holes or the like were cut out was used as a sample for measurement. Then, this measurement sample was fixed to the measurement stage of a microhardness tester installed parallel to a vibration isolation table. After fixing the measurement sample to the measurement stage of the microhardness tester, the Martens hardness of the cross-section of the hard coat layer at a depth of 100 nm was measured under the following measurement conditions. The Martens hardness was determined by measuring arbitrary 3 points near the center of the cross section of the hard coat layer of the measurement sample, and taking the arithmetic mean value of the hardness of the obtained 3 points. When calculating the Martens hardness, it was automatically calculated by selecting "HM" (Martens hardness) as the type of hardness to be measured with the Picodenter HM500. The Martens hardness of the light-transmitting substrate was also measured by the same method as the Martens hardness of the hard coat layer.
(Measurement condition)
・Indenter shape: Vickers (quadrangular pyramid diamond indenter) (regular quadrangular pyramid with a facing angle of 136° at the tip)
・Load control method: up to a maximum load of 40 mN ・Load increase time: 20 seconds ・Creep time: 5 seconds ・Load removal time: 20 seconds ・Push amount: 100 nm
・Temperature at the time of measurement: 25°C
・ Humidity at the time of measurement: 50%
The profile of the measurement was to apply a load from 0 mN to 40 mN over 20 seconds, hold 40 mN for 5 seconds, and then return from 40 mN to 0 mN over 20 seconds.

DESCRIPTION OF SYMBOLS 10... Conductive film with protective film 20... Conductive film 20A... Front surface 20B... Back surface 21... Light transmissive substrate 21A... First surface 21B... Second surface 22... Resin layer 23... Conductive part 24... Conductive Fiber 25... Light transmissive resin 30... Protective film

Claims (4)

forming a resin layer on the first surface side of the light transmissive substrate;
a step of directly forming a conductive portion containing conductive fibers on a second surface opposite to the first surface of the light-transmitting substrate after forming the resin layer;
A step of detachably attaching a protective film to the surface of the conductive part ,
A method for producing a conductive film with a protective film , further comprising the step of removing static electricity from the light-transmissive substrate before forming the conductive portion . 2. The manufacturing method according to claim 1 , wherein the light-transmitting substrate is destaticized before the resin layer is formed. 3. The manufacturing method according to claim 1 or 2 , wherein the light-transmitting substrate has an underlayer only on one side. The light-transmitting base material includes a base material body and an underlayer provided on one surface of the base material body, the surface of the underlayer forming the first surface, and the conductive part being 4. The manufacturing method according to any one of claims 1 to 3 , adjacent to the substrate body.

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