Resin film

Abstract

Provided are: a resin film (1) configured from a material comprising a thermoplastic elastomer, wherein the resin film (1) has a haze value of 20% or less, an average transmittance of light of a wavelength of 400-700 nm of 70% or more, a recovery rate after 10% elongation of 70% or more, and a surface roughness Ra of 20 nm or less; a photoelectric conversion element (10) comprising the resin film (1); and a display comprising the resin film (1).

Description

Resin film

[0001] The present invention relates to a resin film.

[0002] In recent years, improvements in solar cells have progressed, and it is expected that they will be introduced in places where conventional solar cells were difficult to install. In particular, the use of flexible substrates for solar cells makes them less susceptible to cracking or damage, which has expanded the range of installation locations more than ever before.

[0003] JP 2018-125496 A JP 2023-85568 A JP 2018-104869 A

[0004] In order to make solar cells thinner and lighter, various resin films have been considered as substrates for solar cells. However, from the viewpoints of durability and ease of processing, films composed of materials with rigid chemical bonds or crystallinity are often used. For example, Patent Document 1 describes a flexible, heat-resistant organic thin-film solar cell substrate in which polyimide is used. Solar cells using the substrate described in Patent Document 1 are resistant to cracking and breakage. However, due to poor stretchability, particularly poor recovery, installation on three-dimensional curved surfaces has been difficult. If installation on three-dimensional curved surfaces were possible, solar cells could be incorporated into various everyday objects without design constraints.

[0005] Patent Document 2 describes a silicone-based stretchable substrate, and Patent Document 3 describes a urethane-based stretchable substrate. However, these are inventions in the field of wearable devices, and there is no mention of performance such as transparency for transmitting light necessary for power generation, or smoothness for coating a film of several tens to several hundreds of nanometers.

[0006] Therefore, an object of the present invention is to provide a resin film having restorability, transparency and smoothness, and a photoelectric conversion element or a display manufactured using the resin film.

[0007] The resin film according to the embodiment of the present invention that can solve the above problems is as follows: [1] A resin film made of a material containing a thermoplastic elastomer, which has a haze value of 20% or less, an average transmittance of light having a wavelength of 400 nm or more and 700 nm or less of 70% or more, a recovery rate after 10% elongation of 70% or more, and a surface roughness Ra of 20 nm or less.

[0008] By configuring the resin film as described above, it has resilience, transparency, and smoothness. Because the resin film has resilience, it can be easily installed on a three-dimensional curved surface. Because the resin film has transparency, it can easily transmit light. In addition, because the resin film has smoothness, it can easily form a thin film on the surface.

[0009] The resin film according to the embodiment of the present invention is preferably any one of the following [2] to [4]. [2] The resin film according to [1], wherein the stress of the resin film at 50% elongation is 15.0 MPa or less. [3] The resin film according to [1] or [2], wherein the melting point of the thermoplastic elastomer is 120°C or more and 210°C or less. [4] The resin film according to any one of [1] to [3], wherein the thermoplastic elastomer contains 50% by mass or more of a polyester elastomer, a polyurethane elastomer, or a polyamide elastomer.

[0010] The present invention also includes the following [5] and [6]. [5] A photoelectric conversion element comprising: the resin film according to any one of [1] to [4]; a photoelectric conversion layer made of a material containing a photoelectric conversion material; and a first electrode layer disposed between the resin film and the photoelectric conversion layer. [6] A display comprising: the resin film according to any one of [1] to [4]; and a light-emitting element fixed to the resin film.

[0011] The resin film according to the embodiment of the present invention has resilience, transparency, and smoothness. The resilience of the resin film makes it easy to install on a three-dimensional curved surface. The transparency of the resin film makes it easy to transmit light. Furthermore, the smoothness of the resin film makes it easy to provide a thin film on the surface. Photoelectric conversion elements and displays manufactured using the above-mentioned resin film can be easily installed on three-dimensional curved surfaces because the resin film has resilience.

[0012] Fig. 1 is a perspective view of a resin film according to an embodiment of the present invention. Fig. 2 is a cross-sectional view showing an example of a photoelectric conversion element manufactured using the resin film according to an embodiment of the present invention. Fig. 3 is a cross-sectional view showing an example of a display manufactured using the resin film according to an embodiment of the present invention.

[0013] The present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the illustrated examples, and it is possible to carry out the invention by making appropriate modifications within the scope that can comply with the above-mentioned and below-mentioned purposes, and all of these modifications are included in the technical scope of the present invention.

[0014] The resin film according to an embodiment of the present invention is a resin film made of a material containing a thermoplastic elastomer, and has a haze value of 20% or less, an average transmittance of 70% or more for light having a wavelength of 400 nm or more and 700 nm or less, a recovery rate after 10% elongation of 70% or more, and a surface roughness Ra of 20 nm or less.

[0015] Fig. 1 is a perspective view of a resin film according to an embodiment of the present invention. Fig. 2 is a cross-sectional view showing an example of a photoelectric conversion element manufactured using the resin film according to an embodiment of the present invention. More specifically, Fig. 2 shows a photoelectric conversion element 10 having a resin film 1. Fig. 3 is a cross-sectional view showing an example of a display manufactured using the resin film according to an embodiment of the present invention. More specifically, Fig. 3 shows a display 20 having the resin film 1.

[0016] In this specification, unless otherwise specified, the term "longitudinal direction" refers to the MD direction of the resin film, and the term "lateral direction" refers to the TD direction of the resin film. Furthermore, when cutting out a sample for measuring physical properties, the sample is cut out so that the longitudinal direction of the sample is parallel to the MD direction of the resin film, and the transverse direction of the sample is parallel to the TD direction of the resin film.

[0017] The resin film 1 is made of a material containing a thermoplastic elastomer. The entire resin film 1 may be made of only a thermoplastic elastomer, or a thermoplastic elastomer may be used as one of the materials constituting the resin film 1. The material constituting the resin film 1 may be a mixture of a thermoplastic elastomer and other materials. Examples of other materials include a UV absorber and an antioxidant.

[0018] The resin film 1 preferably contains 50% by mass or more of the thermoplastic elastomer, more preferably 70% by mass or more, and even more preferably 90% by mass or more. The resin film 1 may contain 100% by mass or less, or 95% by mass or less of the thermoplastic elastomer.

[0019] The haze value of the resin film 1 is 20% or less. The haze value of the resin film 1 is preferably 15% or less, and more preferably 10% or less. The haze value of the resin film 1 can be 0.1% or more, 0.5% or more, 1% or more, etc. Although only a portion of the resin film 1 may satisfy the above configuration, it is preferable that the entire resin film 1 satisfies the above configuration. By adopting the above configuration, scattering of light when light is irradiated onto the resin film 1 can be easily suppressed. For example, by using the resin film 1 as a base material for a photoelectric conversion element 10 having a photoelectric conversion layer 12 described below, the amount of light transmitted to the photoelectric conversion layer 12 can be easily increased. Furthermore, suppressing light scattering improves transparency, making it easier to install the resin film 1 in places where visibility is required.

[0020] The haze value can be measured in accordance with JIS K 7136 using a haze meter NDH8000 manufactured by Nippon Denshoku Industries Co., Ltd.

[0021] The average transmittance of the resin film 1 for light with a wavelength of 400 nm or more and 700 nm or less is 70% or more. The average transmittance of the resin film 1 for light with a wavelength of 400 nm or more and 700 nm or less is preferably 73% or more, and more preferably 75% or more. The average transmittance of the resin film 1 for light with a wavelength of 400 nm or more and 700 nm or less can be 99% or less, 95% or less, 90% or less, or the like. While only a portion of the resin film 1 may satisfy the above-described structure, it is preferable that the entire resin film 1 satisfy the above-described structure. By adopting the above-described structure, the resin film 1 can be made to easily transmit light. For example, by using the resin film 1 as a base material for a photoelectric conversion element 10 having a photoelectric conversion layer 12 described below, it is possible to make it less likely to impede the transmission of light to the photoelectric conversion layer 12. Furthermore, since transparency is also likely to be improved, it is easier to install the resin film 1 in places where visibility is required.

[0022] The average transmittance of light having a wavelength of 400 nm or more and 700 nm or less is first obtained using an ultraviolet-visible-near-infrared (UV-Vis-NIR) spectrophotometer SolidSpec-3700 (software: UVProve ver. 2.71) manufactured by Shimadzu Corporation. The average transmittance of light having a wavelength of 400 nm or more and 700 nm or less can be calculated from this spectrum.

[0023] The restoration rate of the resin film 1 after 10% elongation is 70% or more. The restoration rate of the resin film 1 after 10% elongation is preferably 80% or more, and more preferably 90% or more. The restoration rate of the resin film 1 after 10% elongation can be 99% or less, 98% or less, etc. Only a portion of the resin film 1 may satisfy the above configuration, but it is preferable that the entire resin film 1 satisfy the above configuration. By adopting the above configuration, the resin film 1 can be made easy to install on a three-dimensional curved surface.

[0024] The recovery rate of resin film 1 after 10% elongation can be determined as follows. First, a sample measuring 150 mm length x 10 mm width is cut out and elongated in the longitudinal direction by 10% using an Autograph AGS-X manufactured by Shimadzu Corporation, with an initial chuck distance of 100 mm and a pulling speed of 50 mm / min. The sample is then returned to the initial position at a speed of 50 mm / min, and the elongation rate at which the stress becomes zero is taken as the permanent set (%). The recovery rate after 10% elongation can be calculated using the following formula: Recovery rate after 10% elongation (%) = (1 - permanent set / 10) x 100

[0025] The surface roughness Ra of the resin film 1 is 20 nm or less. The surface roughness Ra of the resin film 1 is preferably 15 nm or less, and more preferably 10 nm or less. The surface roughness Ra of the resin film 1 can be 1 nm or more, 2 nm or more, 3 nm or more, etc. Only a portion of the resin film 1 may satisfy the above configuration, but it is preferable that the entire resin film 1 satisfy the above configuration. By adopting the above configuration, the resin film 1 can be made smooth.

[0026] The objective lens of the Nano 3D Optical Interferometry System VS1800 manufactured by Hitachi High-Tech Corporation is set to ×10, and a cross-sectional profile of 1 mm in the lateral direction from the resin film 1 is obtained, and the surface roughness Ra can be calculated based on JIS B 0601.

[0027] By configuring the resin film 1 as described above, it has restorability, transparency, and smoothness. Because the resin film 1 has restorability, it can be easily installed on a three-dimensional curved surface. Because the resin film 1 has transparency, it can easily transmit light. Furthermore, because the resin film 1 has smoothness, it can easily form a thin film on the surface.

[0028] Because of the physical properties described above, the resin film 1 can be suitably used, for example, as a base material for the photoelectric conversion element 10 or the display 20. The resin film 1 can be easily installed on a three-dimensional curved surface, so by using this as a base material for the photoelectric conversion element 10 or the display 20, it is possible to make it easy to install on a three-dimensional curved surface. This makes it easy to incorporate the photoelectric conversion element 10 or the display 20 into various things in everyday life without design constraints.

[0029] The stress of the resin film 1 at 50% elongation is preferably 15.0 MPa or less, more preferably 13.0 MPa or less, and even more preferably 10.0 MPa or less. The stress of the resin film 1 at 50% elongation can be 0.1 MPa or more, 0.5 MPa or more, 1.0 MPa or more, etc. Although only a portion of the resin film 1 may satisfy the above structure, it is preferable that the entire resin film 1 satisfy the above structure. This makes it easier to stretch the resin film 1.

[0030] The stress at 50% elongation of the resin film 1 can be measured in accordance with JIS K 7127 by cutting out a sample of 150 mm length x 10 mm width and elongating it by 50% in the longitudinal direction using an Autograph AGS-X manufactured by Shimadzu Corporation, with an initial chuck distance of 100 mm and a tensile speed of 50 mm / min.

[0031] The thickness of the resin film 1 can be 50 μm or more, 70 μm or more, 90 μm or more, etc. The thickness of the resin film 1 can be 450 μm or less, 400 μm or less, 350 μm or less, etc. By adopting the above-mentioned configuration, it becomes easier to prevent the thickness of the resin film 1 from causing a decrease in transparency and whitening of the resin film 1 as a whole when crystallization progresses inside the resin film 1 due to cooling or the like during the production of the resin film 1.

[0032] The thickness of the resin film 1 can be measured using a micrometer manufactured by Mitutoyo Corporation.

[0033] The thermoplastic elastomer may be a polyester elastomer, a polyurethane elastomer, a polyamide elastomer, a polystyrene elastomer, a polyolefin elastomer, a vinyl chloride elastomer, or an acrylic elastomer, and any one of these may be used alone or in combination of two or more.

[0034] The thermoplastic elastomer preferably includes at least one of a polyester elastomer, a polyurethane elastomer, and a polyamide elastomer. The thermoplastic elastomer preferably includes 50% by mass or more of a polyester elastomer, a polyurethane elastomer, or a polyamide elastomer, more preferably 70% by mass or more, and particularly preferably 90% by mass or more. The thermoplastic elastomer may include 100% by mass or less, or 95% by mass or less, of a polyester elastomer, a polyurethane elastomer, or a polyamide elastomer. Note that only a polyester elastomer may be used as the thermoplastic elastomer.

[0035] The melting point of the thermoplastic elastomer is preferably 120°C or higher, more preferably 130°C or higher, and even more preferably 140°C or higher. This makes it easier to provide heat resistance to typical annealing temperatures when annealing films such as the first electrode layer 11 and the photoelectric conversion layer 12 described below. The melting point of the thermoplastic elastomer is preferably 210°C or lower, more preferably 200°C or lower, and even more preferably 190°C or lower. This makes it easier to prevent a decrease in stretchability or a decrease in film transparency due to increased crystallinity corresponding to a high melting point.

[0036] The melting point of the thermoplastic elastomer can be measured using a DSC220 differential scanning calorimeter manufactured by Seiko Electronics Co., Ltd. Specifically, 5 mg of the thermoplastic elastomer is placed in an aluminum pan, the pan is sealed with a lid, and the pan is melted in nitrogen at 250°C for 2 minutes. The pan is then cooled to 50°C at a rate of 20°C / min, and the pan is then heated from 50°C to 250°C at a rate of 20°C / min to obtain a thermogram. The endothermic peak due to melting obtained from the thermogram is the melting point.

[0037] The melt extrusion method is preferred as a method for forming the resin film 1 from the thermoplastic elastomer. Examples of the melt extrusion method include inflation, T-die, biaxial stretching, and casting, and the T-die method is particularly preferred for film formation. Furthermore, the resin film 1 may be a stretched film, but is preferably an unstretched film.

[0038] Next, a photoelectric conversion element 10 that can be manufactured using the resin film 1 according to the embodiment of the present invention will be described.

[0039] The photoelectric conversion element 10 has a configuration in which a laminated structure having a photoelectric conversion function is provided on a resin film 1. Each of the members (hereinafter, also referred to as layers) constituting the laminated structure preferably has a configuration that is easily stretchable. A member having an easily stretchable configuration means that when the photoelectric conversion element 10 is installed so that the resin film 1 conforms to a three-dimensional curved surface, the member can stretch to a degree that does not cause the photoelectric conversion function to be lost in response to the expansion and contraction of the resin film 1. To achieve such an easily stretchable configuration for a member, for example, a material that can impart stretchability to the member may be used as the material constituting the member, and / or the physical structure of the member may be a structure that can impart stretchability to the member, such as a bellows structure. In this specification, "A and / or B" means "only one of A and B" or "both A and B," specifically meaning "A," "B," or "A and B."

[0040] Examples of the photoelectric conversion element 10 include a solar cell and a photodiode.

[0041] In addition to the resin film 1, the photoelectric conversion element 10 according to the embodiment of the present invention preferably includes, as components of the laminate structure, a photoelectric conversion layer 12 composed of a material containing a photoelectric conversion material, and a first electrode layer 11 disposed between the resin film 1 and the photoelectric conversion layer 12. Because the resin film 1 is easily installed on a three-dimensional curved surface, using it as the base material of the photoelectric conversion element 10 makes it easy to install on a three-dimensional curved surface. This makes it easy to incorporate the photoelectric conversion element 10 into various everyday objects without design constraints. Furthermore, because the resin film 1 is transparent and can easily transmit light, using the resin film 1 as the base material of the photoelectric conversion element 10 makes it less likely to impede light transmission to the photoelectric conversion layer 12.

[0042] The first electrode layer 11 is preferably laminated on the resin film 1 .

[0043] The first electrode layer 11 can be made of a conductive material. As described above, the first electrode layer 11 preferably has a configuration that is easily stretchable. For example, the first electrode layer 11 may be made of stretchable wiring such as stretchable metal paste wiring, and / or may be made of stretchable bellows-shaped metal wiring. The first electrode layer 11 is more preferably a transparent electrode. For example, it is preferable to use a transparent stretchable electrode made of a conductive polymer or nanocarbon, which is an example of the stretchable wiring, as the first electrode layer 11. This makes it easier for light to reach the photoelectric conversion layer 12. The first electrode layer 11 may be made of only one of the above materials, or may be made of two or more of the above materials.

[0044] The first electrode layer 11 can be formed by, for example, vapor-depositing or applying the above-mentioned material to the resin film 1 .

[0045] The photoelectric conversion layer 12 may be stacked on the first electrode layer 11. A buffer layer such as a hole transport layer or an electron transport layer may be disposed between the first electrode layer 11 and the photoelectric conversion layer 12.

[0046] The photoelectric conversion layer 12 is preferably made of a material containing a photoelectric conversion material. The photoelectric conversion layer 12 may be made of only the photoelectric conversion material, or may be made of the photoelectric conversion material and other materials. As described above, it is preferable that the photoelectric conversion layer 12 has a configuration that is easy to stretch.

[0047] As the photoelectric conversion material, for example, organic semiconductor materials such as p-type and n-type semiconductors can be used. The p-type and n-type semiconductors may each have an independent layer structure, or a structure in which a p-type semiconductor layer and an n-type semiconductor layer are stacked. A single layer may also be formed by mixing p-type and n-type semiconductors. When the p-type and n-type semiconductors are used as the photoelectric conversion material, the photoelectric conversion element 10 becomes an organic thin-film solar cell. Other usable photoelectric conversion materials include materials having a perovskite structure. When a material having a perovskite structure is used as the photoelectric conversion material, the photoelectric conversion element 10 becomes a perovskite solar cell. Because the resin film 1 is transparent, for example, when the photoelectric conversion element 10 is an organic thin-film solar cell using the p-type and n-type semiconductors as the photoelectric conversion material, the photoelectric conversion element 10 as a whole can have excellent transparency. Therefore, even when the photoelectric conversion element 10 is installed on the window glass of a building or an automobile, it does not detract from the appearance of the building or automobile. Even when the photoelectric conversion element 10 is a perovskite solar cell, the transparency of the resin film 1 prevents the resin film 1 from damaging the appearance during installation.

[0048] The photoelectric conversion layer 12 can be formed, for example, by depositing or applying the above-mentioned material onto the resin film 1 on which the first electrode layer 11 is provided.

[0049] By using a resin film 1 having an average transmittance of 70% or more for light with a wavelength of 400 nm or more and 700 nm or less as the base material of the photoelectric conversion element 10, it is possible to make it difficult for light to be transmitted to the photoelectric conversion layer 12.

[0050] The photoelectric conversion element 10 may further include a second electrode layer 13 as a component of the laminated structure. The second electrode layer 13 may be laminated on the photoelectric conversion layer 12. The second electrode layer 13 is preferably provided such that the photoelectric conversion layer 12 is disposed between the second electrode layer 13 and the first electrode layer 11. A buffer layer such as a hole transport layer or an electron transport layer may be disposed between the second electrode layer 13 and the photoelectric conversion layer 12. Furthermore, a buffer layer such as a hole transport layer or an electron transport layer may be disposed between the first electrode layer 11 and the photoelectric conversion layer 12. As shown in FIG. 2 , the photoelectric conversion element 10 may be configured such that a portion of the second electrode layer 13 is laminated on the photoelectric conversion layer 12, and the remaining portion of the second electrode layer 13 is laminated on the first electrode layer 11. Note that when the portion facing upward in FIG. 2 is defined as the top surface, the portion facing downward is defined as the bottom surface, and the portions facing left and right are defined as side surfaces, it is preferable that a portion of the second electrode layer 13 is disposed so as to abut the top surface and side surfaces of the photoelectric conversion layer 12. Figure 2 shows an example in which a resin film 1 has multiple unit structures, each having a first electrode layer 11, a photoelectric conversion layer 12, and a second electrode layer 13 arranged in this order, and between adjacent unit structures, the second electrode layer 13 of one unit structure is electrically connected to the first electrode layer 11 of the other unit structure.

[0051] The second electrode layer 13 can be made of a conductive material. As described above, the second electrode layer 13 preferably has a configuration that is easily stretchable. For example, the second electrode layer 13 may be made of a stretchable wiring such as a stretchable metal paste wiring, and / or may be made of a stretchable bellows-shaped metal wiring. The second electrode layer 13 may be a transparent electrode. For example, the second electrode layer 13 may be made of a transparent stretchable electrode that uses a conductive polymer or nanocarbon, which is an example of the stretchable wiring.

[0052] The second electrode layer 13 can be formed, for example, by depositing or applying the above-mentioned material onto the resin film 1 on which the first electrode layer 11 and the photoelectric conversion layer 12 are provided.

[0053] The annealing treatment may be performed while the first electrode layer 11, the photoelectric conversion layer 12, and the second electrode layer 13 are laminated on the resin film 1, or may be performed at any stage when part of the above layer structure is laminated.

[0054] The photoelectric conversion element 10 may further include a protective layer 14 as a component of the laminated structure. The protective layer 14 is preferably laminated on the second electrode layer 13. As shown in FIG. 2 , the photoelectric conversion element 10 may be configured such that a portion of the protective layer 14 is laminated on the second electrode layer 13, another portion of the protective layer 14 is laminated on the photoelectric conversion layer 12, and the remaining portion of the protective layer 14 is laminated on the first electrode layer 11. As shown in FIG. 2 , the second electrode layer 13 and the photoelectric conversion layer 12 may be disposed between the first electrode layer 11 and the protective layer 14. Although not shown, the photoelectric conversion element 10 may be configured such that a portion of the protective layer 14 is laminated on the resin film 1.

[0055] The protective layer 14 preferably has gas barrier properties. The protective layer 14 may have a structure of two or more layers including a barrier layer having gas barrier properties. As described above, the protective layer 14 preferably has a configuration that is easily stretchable. For example, a stretchable elastomer may be used as the material of the protective layer 14.

[0056] As shown in FIG. 2, it is preferable that light 15 is applied to the photoelectric conversion element 10 from the side where the resin film 1 is located.

[0057] The photoelectric conversion element 10 can be attached to, for example, the rear glass or windshield of an automobile. The photoelectric conversion element 10 uses the restorable resin film 1 as a base material, so that it can be easily attached to the rear glass or windshield of an automobile having a three-dimensional curved surface.

[0058] Next, a display 20 that can be manufactured using the resin film 1 according to the embodiment of the present invention will be described.

[0059] The display 20 according to the embodiment of the present invention preferably includes the resin film 1 and a light-emitting element 21 fixed to the resin film 1. The display 20 may be a so-called transparent display. Since the resin film 1 can be easily installed on a three-dimensional curved surface, using the resin film 1 as the base material of the display 20 makes it possible to easily install the display 20 on a three-dimensional curved surface. This makes it easy to incorporate the display 20 into various everyday objects without design restrictions.

[0060] The light emitting element 21 may be in contact with the resin film 1. The light emitting element 21 may not be in contact with the resin film 1. For example, the light emitting element 21 may be fixed in a state in which another member is disposed between the light emitting element 21 and the resin film 1.

[0061] An LED can be used as the light-emitting element 21. When an organic light-emitting diode is used as the light-emitting element 21, the display 20 becomes an organic EL display. When a micro light-emitting diode is used as the light-emitting element 21, the display 20 becomes, for example, a micro LED display. Each of the members constituting the light-emitting element 21 may have a configuration that is easy to stretch, for example, as described above with respect to the photoelectric conversion element 10.

[0062] The display 20 may further include conductive wiring 22. The wiring 22 is preferably fixed to the resin film 1 and the light-emitting element 21. As described above, the wiring 22 may have a configuration that allows it to easily stretch.

[0063] The display 20 may further include a protective layer 23. The protective layer 23 may be configured such that a portion of the protective layer 23 is laminated on the resin film 1, another portion of the protective layer 23 is laminated on the light-emitting element 21, and the remaining portion of the protective layer 23 is laminated on the wiring 22. As described above, the protective layer 23 may be configured to be easily stretchable.

[0064] The display 20 can be attached to, for example, the rear glass or windshield of an automobile. The display 20 uses the restorable resin film 1 as a base material, so that the display 20 can be easily attached to the rear glass or windshield of an automobile having a three-dimensional curved surface.

[0065] This application claims the benefit of priority based on Japanese Patent Application No. 2024-118830, filed on July 24, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-118830, filed on July 24, 2024, are incorporated herein by reference.

[0066] The resin film according to the embodiment of the present invention will be described in detail below with reference to examples, but the resin film according to the embodiment of the present invention is not limited to these examples.

[0067] The films used in the examples and comparative examples are as follows:

[0068] (Examples 1 and 2) Pelprene (registered trademark) P-30B manufactured by Toyobo MC Co., Ltd. was used as the pellet material. The pellet material was melt-extruded into a film using a T-die extruder, brought into contact with a mirror-finish chilled roll at 20°C, and wound up with an interleaf sheet sandwiched between them, to produce resin films according to Examples 1 and 2. The barrel temperature and die temperature during extrusion were set to the melting point + 30°C. The resin film was unstretched. The thickness of the resin film was adjusted by changing the rotation speed of the mirror-finish chilled roll.

[0069] Example 3 Pelprene (registered trademark) P-40H manufactured by Toyobo MC Co., Ltd. was used as the pellet material. The pellet material was melt-extruded into a film using a T-die extruder, brought into contact with a mirror-finish chilled roll at 20°C, and wound up with an interleaving sheet sandwiched between them, thereby producing a resin film according to Example 3. The barrel temperature and die temperature during extrusion were set to the melting point + 30°C. The resin film was unstretched. The thickness of the resin film was adjusted by changing the rotation speed of the mirror-finish chilled roll.

[0070] Example 4 Pelprene (registered trademark) P-55B manufactured by Toyobo MC Co., Ltd. was used as the pellet material. The pellet material was melt-extruded into a film using a T-die extruder, brought into contact with a mirror-finish chilled roll at 20°C, and wound up with an interleaf sheet sandwiched between them, to produce a resin film according to Example 4. The barrel temperature and die temperature during extrusion were set to the melting point + 30°C. The resin film was unstretched. The thickness of the resin film was adjusted by changing the rotation speed of the mirror-finish chilled roll.

[0071] (Comparative Example 1) Pelprene (registered trademark) P-150B manufactured by Toyobo MC Co., Ltd. was used as the pellet material. The pellet material was melt-extruded into a film using a T-die extruder, brought into contact with a mirror-surface chilled roll at 20°C, and wound up with an interleaf sheet sandwiched between them, to produce a film according to Comparative Example 1. The barrel temperature and die temperature during extrusion were set to the melting point + 30°C. The film was unstretched. The thickness of the film was adjusted by changing the rotation speed of the mirror-surface chilled roll.

[0072] (Comparative Example 2) Pelprene (registered trademark) P-55B manufactured by Toyobo MC Co., Ltd. was used as the pellet material. The pellet material was injected using an injection molding machine and poured into a mirror-finished mold to produce a film according to Comparative Example 2. The barrel temperature during injection molding was set to the melting point + 30°C. The mold was cooled with cooling water to a temperature of 20°C.

[0073] Comparative Example 3 In Comparative Example 3, a polyester film Cosmoshine (registered trademark) A4160 manufactured by Toyobo Co., Ltd. was used.

[0074] Comparative Example 4 In Comparative Example 4, a silicone rubber film 6-9085-13 manufactured by AS ONE Corporation was used.

[0075] The methods for measuring the physical properties of the films of each Example and Comparative Example are as follows. Unless otherwise specified, the term "longitudinal direction" refers to the MD direction of the film, and the term "lateral direction" refers to the TD direction of the film. Furthermore, when cutting out a sample for measuring physical properties, the sample is cut so that the longitudinal direction of the sample is parallel to the MD direction of the film, and the transverse direction of the sample is parallel to the TD direction of the film.

[0076] (Haze Value) According to JIS K 7136, the haze value of each film was measured three times using a haze meter NDH8000 manufactured by Nippon Denshoku Industries Co., Ltd., and the average of the measured values ​​is shown in Tables 1 and 2.

[0077] (Average transmittance of light with wavelengths of 400 nm or more and 700 nm or less) The transmittance of light with wavelengths of 400 nm or more and 700 nm or less was measured by ultraviolet-visible spectroscopy under the following measurement conditions. The light transmittance was measured using an integrating sphere with an ultraviolet-visible-near-infrared (UV-Vis-NIR) spectrophotometer SolidSpec-3700 (software: UVProve ver. 2.71) manufactured by Shimadzu Corporation. <Measurement conditions> Measurement wavelength: 400 nm or more and 700 nm or less Scan speed: Medium speed Slit width: 12 nm Sampling pitch: 0.5 nm Standard white plate: Spectralon standard reflector The average transmittance of light with wavelengths of 400 nm or more and 700 nm or less was calculated and is shown in Tables 1 and 2.

[0078] (Restoration rate after 10% elongation) A sample measuring 150 mm length x 10 mm width was cut out from each film and elongated by 10% in the longitudinal direction using an Autograph AGS-X manufactured by Shimadzu Corporation, with an initial chuck distance of 100 mm and a pulling speed of 50 mm / min. The sample was then returned to the initial position at a speed of 50 mm / min, and the elongation rate at which the stress became zero was taken as the permanent set (%). The restoration rate after 10% elongation was calculated using the following formula and is shown in Tables 1 and 2. Restoration rate after 10% elongation (%) = (1 - permanent set / 10) x 100

[0079] (Surface roughness Ra) The objective lens of a Hitachi High-Technologies Nano 3D optical interference measurement system VS1800 was set to ×10, a cross-sectional profile of 1 mm in the lateral direction was obtained from each film, and the surface roughness Ra was calculated based on JIS B 0601. This was performed at any three locations, and the average of the surface roughness Ra calculated from the three locations is shown in Tables 1 and 2.

[0080] (Stress at 50% Elongation) The stress at 50% elongation was measured in accordance with JIS K 7127. A sample of 150 mm length x 10 mm width was cut out from each film, and the stress was measured using an Autograph AGS-X manufactured by Shimadzu Corporation when the sample was elongated by 50% lengthwise at an initial chuck distance of 100 mm and a tensile speed of 50 mm / min. The results are shown in Tables 1 and 2.

[0081] (Melting Point) A differential scanning calorimeter DSC220 manufactured by Seiko Electronics Co., Ltd. was used. Specifically, 5 mg of the sample pellet material was placed in an aluminum pan, the pan was sealed with a lid, and the sample was melted in nitrogen at 250°C for 2 minutes. The temperature was then lowered to 50°C at a rate of 20°C / min, and the temperature was then increased from 50°C to 250°C at a rate of 20°C / min to obtain a thermogram curve. The endothermic peak due to melting was determined from the obtained thermogram curve, and this was shown as the melting point in Tables 1 and 2.

[0082] (Thickness) Measurements were made at five arbitrary points in the transverse direction of each film using a micrometer manufactured by Mitutoyo Corp. The average thickness was shown in Tables 1 and 2 as the thickness of each film.

[0083] (Ease of installation on three-dimensional curved surfaces) The ease of installation on three-dimensional curved surfaces of the film of Example 3 and the film of Comparative Example 3 was evaluated using a watch glass manufactured by SCHOTT. The watch glass used was made of borosilicate glass DURAN (registered trademark) and had a diameter C of 50 mm and a depth h of 5 mm. The surface was approximately spherical, and the radius of curvature R could be calculated using the following formula: R = h / 2 + C ２ / 8h The calculated radius of curvature R was 65 mm. Each film was fixed to a 100 mm x 100 mm metal frame. The watch glass was placed on a vacuum device with the convex side facing upwards, and each film fixed to the metal frame was positioned to cover the entire outer surface of the watch glass, and vacuum suction was applied. Each film was then aligned along the outer surface of the watch glass, and visual inspection was performed to ensure there were no wrinkles on each film. Films with multiple large wrinkles were poorly suited to installation on three-dimensional curved surfaces. Films with no wrinkles were excellently suited to installation on three-dimensional curved surfaces. In Tables 1 and 2, an "x" is indicated if multiple large wrinkles were present and the film was poorly suited to installation on a three-dimensional curved surface, and an "o" is indicated if no wrinkles were present and the film was excellently suited to installation on a three-dimensional curved surface. The arc L of the watch glass can be calculated as 51.32 from L = Rα (where α (radian) = sin －１ (C / 2R)) And L / C=1.026. Therefore, each film is stretched by at least 2.6%.

[0084]

[0085]

[0086] As is clear from Table 1, all of Examples 1 to 4 have low haze values, high average transmittance for light with wavelengths of 400 nm to 700 nm, and therefore excellent transparency, low surface roughness Ra, and high recovery rate after 10% elongation, and therefore excellent recovery. Furthermore, the film of Example 3, which was evaluated for ease of application to a three-dimensional curved surface, was confirmed to be able to be applied to the three-dimensional curved surface without wrinkles.

[0087] The film of Comparative Example 1 whitened during extrusion molding. As shown in Table 2, the film of Comparative Example 1 had a high haze value and a low average transmittance of light with a wavelength of 400 nm to 700 nm, resulting in poor transparency. The film of Comparative Example 2 whitened during cooling after injection molding. As shown in Table 2, the film of Comparative Example 2 had a high haze value and a low average transmittance of light with a wavelength of 400 nm to 700 nm, resulting in poor transparency. As shown in Table 2, the film of Comparative Example 3 had a low haze value and a high average transmittance of light with a wavelength of 400 nm to 700 nm, resulting in excellent transparency, and a small surface roughness Ra, resulting in excellent surface smoothness. However, the recovery rate after 10% elongation was low and the stress at 50% elongation was high, resulting in poor stretchability and recovery. Therefore, when the film of Comparative Example 3 was placed on a three-dimensional curved surface, multiple large wrinkles occurred, making it impossible to place it neatly on the three-dimensional curved surface. As shown in Table 2, the film of Comparative Example 4 has a high recovery rate after 10% elongation and is excellent in recovery, but has a large surface roughness Ra and is therefore inferior in surface smoothness.

[0088] 1: Resin film 10: Photoelectric conversion element 11: First electrode layer 12: Photoelectric conversion layer 13: Second electrode layer 14: Protective layer 15: Light 20: Display 21: Light-emitting element 22: Wiring 23: Protective layer

Claims

1. A resin film made from a material containing a thermoplastic elastomer, which has a haze value of 20% or less, an average transmittance of light with a wavelength of 400 nm or more and 700 nm or less of 70% or more, a recovery rate after 10% elongation of 70% or more, and a surface roughness Ra of 20 nm or less.

2. The resin film according to claim 1, wherein the stress of said resin film at 50% elongation is 15.0 MPa or less.

3. The resin film according to claim 1 or 2, wherein the melting point of the thermoplastic elastomer is 120°C or higher and 210°C or lower.

4. The resin film according to claim 1 or 2, wherein the thermoplastic elastomer contains 50% by mass or more of any one of polyester elastomer, polyurethane elastomer, and polyamide elastomer.

5. A photoelectric conversion element comprising: the resin film according to claim 1 or 2; a photoelectric conversion layer made of a material containing a photoelectric conversion material; and a first electrode layer disposed between the resin film and the photoelectric conversion layer.

6. A display comprising the resin film according to claim 1 or 2, and a light-emitting element fixed to the resin film.

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