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JP-2026074516-A - Hard coat film

JP2026074516AJP 2026074516 AJP2026074516 AJP 2026074516AJP-2026074516-A

Abstract

[Problem] To provide a hard coat film that, when used in solar cells, can provide gas barrier performance and ultraviolet shielding performance without increasing the number of components, and has a sufficiently high total light transmittance. [Solution] A gas barrier layer is provided on one side of a transparent substrate, and a hard coat layer containing an ultraviolet-curable resin is laminated on the other side of the transparent substrate, the light transmittance at a wavelength of 365 nm is less than 10%, the light transmittance at a wavelength of 440 nm is 80% or more, and the total light transmittance is 80% or more. [Selection Diagram] Figure 1

Inventors

  • 野上 花歩子
  • 泉 香
  • 眞壁 岳史

Assignees

  • 日本製紙株式会社

Dates

Publication Date
20260507
Application Date
20241021

Claims (5)

  1. A hard coat film characterized by having a gas barrier layer on one side of a transparent substrate, a hard coat layer containing an ultraviolet-curable resin laminated on the other side of the transparent substrate, a light transmittance of less than 10% at a wavelength of 365 nm, a light transmittance of 80% or more at a wavelength of 440 nm, and a total light transmittance of 80% or more.
  2. The hard coat film according to claim 1, characterized in that the light transmittance at wavelengths of 365 to 380 nm is less than 25%, and the light transmittance at wavelengths of 436 to 440 nm is 75% or more.
  3. The hard coat film according to claim 1 or 2, characterized in that the remaining percentage of the hard coat layer, as measured by the cross-cut method of JIS-K5600-5-6, is 100%.
  4. A solar cell characterized by comprising the hard coat film described in claim 1 or 2.
  5. The solar cell according to claim 4, which is a film-type solar cell having a film shape.

Description

This invention relates to a hard coat film. In recent years, perovskite solar cells using perovskite compounds have been rapidly attracting attention. Perovskite solar cells are known to have excellent light energy conversion efficiency, and, like organic solar cells such as dye-sensitized solar cells and organic thin-film solar cells, thin films can be easily manufactured by coating and drying a solution (Patent Document 1). Perovskite solar cell modules are known to be susceptible to water vapor. Furthermore, elements used in electronic devices such as solar cells are generally vulnerable to ultraviolet (UV) radiation. For example, prolonged exposure of film-type solar cells to UV radiation can lead to problems such as a decrease in photoelectric conversion efficiency. Therefore, the outermost layer of a perovskite solar cell module requires not only water vapor barrier performance but also UV shielding performance. While laminating a film with gas barrier properties and a film with UV shielding properties could be considered to satisfy these requirements, simply laminating films with individual functions would not only increase costs but also increase the overall thickness of the module. Patent Document 2 describes a laminate obtained by bonding two transparent gas barrier films together with an adhesive, then further bonding a transparent resin film with UV-blocking properties to this laminate, and finally coating this laminate with a UV-curable resin. Japanese Patent Publication No. 2014-72327International Publication No. 2018/181181 This is a cross-sectional view showing the schematic configuration of a hard coat film according to an embodiment of the present invention.This is a cross-sectional view showing the schematic configuration of the gas barrier layer laminated film (gas barrier film) of Comparative Example 2.This is a cross-sectional view showing the schematic structure of the hard coat film of Comparative Example 3. The present invention will be described in detail below with reference to the drawings. In this invention, "～" includes the endpoints. That is, "X～Y" includes the values X and Y at both ends. The hard coat film of the present invention has a gas barrier layer on one side of a transparent substrate, and a hard coat layer containing an ultraviolet-curable resin is laminated on the other side of the transparent substrate. It is characterized by having a light transmittance of less than 10% at a wavelength of 365 nm, a light transmittance of 80% or more at a wavelength of 440 nm, and a total light transmittance of 80% or more. Figure 1 is a cross-sectional view showing the schematic configuration of a hard coat film according to an embodiment of the present invention. As shown in Figure 1, the hard coat film 2 has a gas barrier layer 6 on one side of a transparent substrate film 4, and a hard coat layer 8 containing an ultraviolet-curable resin is laminated on the other side of the transparent substrate film 4. (transparent base material) The transparent substrate used in the present invention may be formed from a transparent material capable of transmitting light in the visible light wavelength range. The material of the transparent substrate is not particularly limited, but examples include polyethylene terephthalate (PET), cycloolefin, polyimide (PI), polyethylene naphthalate, polyethylene, polypropylene, polyether ether ketone (PEEK), acrylic resin, polystyrene, triacetylcellulose, and polyvinyl chloride. It is preferable to use films and sheets of the above transparent materials as the transparent substrate. Furthermore, from the viewpoint of transparency, polyethylene terephthalate (PET) is preferred, from the viewpoint of heat resistance, polyimide (PI) and polyether ether ketone (PEEK) are preferred, and among these, polyethylene terephthalate (PET) is more preferred from the viewpoint of processability and cost. Furthermore, in the present invention, when the transparent substrate is a film, the thickness of the transparent substrate is preferably in the range of 10 μm to 1000 μm, and more preferably in the range of 20 μm to 300 μm, from the viewpoint of mechanical strength, handling properties, etc. In this invention, the total light transmittance of the transparent substrate is not particularly limited as long as a hard coat film within the range of the present invention is obtained, but it is preferably 80 to 100%, and more preferably 85 to 100%. (Gas barrier layer) The gas barrier layer is preferably one that blocks water vapor and oxygen, and is particularly preferably one that is impermeable to water vapor, i.e., one with excellent water vapor barrier performance. For example, the gas barrier layer can be a layer containing silica or metal. The thickness of the gas barrier layer is not particularly limited, but is preferably in the range of 0.1 to 10 μm, and more preferably in the range of 0.2 to 1 μm. Below 0.1 μm, sufficient gas barrier performance tends not to be ob