Resin panel and infrared sensor

Abstract

A resin panel is provided, which can make the infrared sensor fully function when used as a protective cover of the infrared sensor. A resin panel is a resin panel having at least a core layer, wherein the light transmittance of the resin panel at a wavelength of 905nm is greater than 85% and the visible light transmittance is less than 20%.

Description

Technical Field

[0001] The invention relates to a resin panel and an infrared sensor. Background Art

[0002] In recent years, the development of optical sensors such as LiDAR has been advancing in the fields of autonomous driving of cars. These optical sensors are sometimes equipped with protective covers in front of the light emitting element and the light receiving element.

[0003] The protective cover of the optical sensor is formed, for example, to protect the light emitting element and the light receiving element from the influence of flying stones, sunlight, wind and rain, etc. Therefore, the protective cover preferably has excellent impact resistance and weather resistance. For example, Patent Document 1 proposes configuring an optical element made of polycarbonate as a protective cover.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-32505 (Claim 1, paragraph 0042) Summary of the invention

[0007] Problems to be solved by the invention

[0008] In order to reduce the impact on human eyes, the light emitting element of the optical sensor sometimes uses infrared light as the emission wavelength. In particular, the light emitting element of the optical sensor (mainly LiDAR) installed in the car often uses infrared light as the emission wavelength.

[0009] However, when the optical element made of polycarbonate disclosed in Patent Document 1 is used as a protective cover for a light sensor (infrared sensor) that emits light in the infrared region as a wavelength, the infrared sensor frequently fails to fully function. In particular, when a pattern layer is provided on the protective cover to improve the aesthetics, there is a tendency that the infrared sensor fails to fully function.

[0010] An object of the present invention is to provide a resin panel and an infrared sensor having the resin panel, wherein when the resin panel is used as a protective cover of the infrared sensor, the infrared sensor can fully exert its function.

[0011] Means for solving problems

[0012] In order to solve the above-mentioned problems, the present invention provides the following [1] to [2].

[0013] [1] A resin panel having at least a core layer, wherein the light transmittance of the resin panel at a wavelength of 905 nm is 85% or more and the visible light transmittance is 20% or less.

[0014] [2] An infrared sensor comprising an infrared light emitting element, an infrared light receiving element, and a protective cover arranged in front of the infrared light emitting element and the infrared light receiving element, wherein the protective cover is the resin panel of [1].

[0015] Effects of the Invention

[0016] When the resin panel of the present invention is used as a protective cover of an infrared sensor, the infrared sensor can fully function. In addition, the infrared sensor of the present invention having the resin panel can fully function. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a cross-sectional view showing one embodiment of the resin panel of the present invention.

[0018] Figure 2 This is a cross-sectional view showing another embodiment of the resin panel of the present invention.

[0019] Figure 3 This is a cross-sectional view showing another embodiment of the resin panel of the present invention.

[0020] Figure 4 This is a cross-sectional view showing another embodiment of the resin panel of the present invention.

[0021] Figure 5 This is a cross-sectional view showing another embodiment of the resin panel of the present invention.

[0022] Figure 6 This is a cross-sectional view showing another embodiment of the resin panel of the present invention. DETAILED DESCRIPTION

[0023] [Resin panel]

[0024] The resin panel of the present invention is a resin panel having at least a core layer, wherein the light transmittance of the resin panel at a wavelength of 905 nm is 85% or more and the visible light transmittance is 20% or less.

[0025] Figure 1 to Figure 6 This is a cross-sectional view showing one embodiment of the resin panel of the present invention.

[0026] Figure 1 to Figure 6 The resin panels (100) each have a core layer (10).

[0027] in addition, Figure 1 to Figure 6The resin panel (100) has an inner layer (20) in addition to the core layer (10), and the inner layer (20) has an anti-reflection layer (23) and the like.

[0028] in addition, Figure 1 to Figure 5 The resin panel (100) has an outer layer (30) in addition to the core layer (10), and the outer layer (30) has a hard coating layer B (35) and the like.

[0029] It should be noted that, in this specification, the "inner layer" refers to the following layer: when the resin panel is used as a protective cover for the infrared sensor, the layer is located on the side of the infrared light emitting element and the infrared light receiving element with the core layer as the reference. Similarly, in this specification, the "outer layer" refers to the following layer: when the resin panel is used as a protective cover for the infrared sensor, the layer is located on the side opposite to the infrared light emitting element and the infrared light receiving element with the core layer as the reference.

[0030] <Transmittance>

[0031] The resin panel of the present invention needs to have a light transmittance of 85% or more at a wavelength of 905 nm and a visible light transmittance of 20% or less. It should be noted that when any of the front and back surfaces of the resin panel is used as the light incident surface, the above values ​​must be met.

[0032] When the transmittance of the wavelength 905nm is less than 85%, the detection function of the infrared sensor using the infrared light of the wavelength 905nm as the emission wavelength cannot be fully exerted. In addition, even if the transmittance of the wavelength 905nm is more than 85%, when the visible light transmittance exceeds 20%, operation errors based on visible light such as sunlight may occur, and the function of the infrared sensor cannot be fully exerted. In addition, by making the visible light transmittance less than 20%, the infrared light emitting element and the infrared light receiving element arranged inside the infrared sensor can be easily made invisible.

[0033] The light transmittance of the resin panel at a wavelength of 905 nm is preferably 86% or more, more preferably 88% or more. The upper limit of the light transmittance of the resin panel at a wavelength of 905 nm is not particularly limited, but is usually 97% or less.

[0034] In order to increase the light transmittance of the resin panel at a wavelength of 905 nm, it is preferred to include a low reflection layer described below, and it is further preferred that the refractive index and thickness of the low reflection layer be within the ranges described below.

[0035] In this specification, the light transmittance of the resin panel at a wavelength of 905 nm and the visible light transmittance described later are average values ​​of 20 measured values.

[0036] The visible light transmittance of the resin panel is preferably 15% or less, more preferably 13% or less, and further preferably 11% or less.

[0037] In order to reduce the visible light transmittance, carbon black is generally used. However, carbon black absorbs light in the infrared region and reduces the transmittance of a wavelength of 905 nm. Therefore, in order to reduce the visible light transmittance of the resin panel, it is preferred to use one or more compounds selected from the azomethine azo compounds and perylene compounds described below.

[0038] It should be noted that even if the visible light transmittance is excessively reduced, further effects are difficult to obtain, and on the other hand, the transmittance of light at a wavelength of 905 nm may be reduced. Therefore, the visible light transmittance of the resin panel is preferably 1% or more, and more preferably 2% or more.

[0039] It should be noted that in this specification, "visible light transmittance" refers to the average value of spectral transmittance at wavelengths of 380 nm to 780 nm. The measurement wavelength interval is 1 nm.

[0040] <Core Layer>

[0041] The core layer preferably contains a resin or glass as a main component, and more preferably contains a resin as a main component from the viewpoint of moldability.

[0042] The main component refers to 50% by mass or more of the total solid content constituting the core layer, preferably 70% by mass or more, and more preferably 90% by mass or more.

[0043] When the core layer contains a resin, a thermoplastic resin is preferably used from the viewpoint of ease of injection molding such as insert molding and in-mold molding.

[0044] Examples of the thermoplastic resin include one or a mixture selected from polystyrene resins, polyolefin resins, ABS resins, AS resins, AN resins, polyphenylene ether resins, polycarbonate resins, polyacetal resins, acrylic resins, polyethylene terephthalate resins, polybutylene terephthalate resins, polysulfone resins, and polyphenylene sulfide resins. Among these, polycarbonate resins and acrylic resins are preferred, and polycarbonate resins having excellent impact resistance are more preferred.

[0045] -Azomethine azo compounds, perylene compounds-

[0046] The core layer preferably contains one or more compounds selected from azomethine azo compounds and perylene compounds. Azomethine azo compounds and perylene compounds are black pigments that absorb light in the visible light region and transmit light in the infrared region. Therefore, by making the core layer contain one or more compounds selected from azomethine azo compounds and perylene compounds, the visible light transmittance of the resin panel can be reduced, and the transmittance of the wavelength of 905nm can be easily maintained in a high range.

[0047] The azomethine azo compound is an azo compound having an azomethine group. Examples of the azo compound having an azomethine group include compounds having an azo group and having a structural unit represented by the following general formula (1) in the molecule.

[0048] The azomethine azo compound can be produced by the method described in, for example, JP-A No. 63-91283 and JP-A No. 62-32149.

[0049] Examples of the azomethine azo compound include compounds having a diazo group which are reaction compounds of tetrachlorophthalimide and aminoaniline.

[0050] [Chemistry 1]

[0051]

[0052] [In formula (1), "Ar" is a residue of an aromatic compound or a heterocyclic compound, "X" is a hydrogen atom or a halogen atom, and "m" is an integer greater than or equal to 1 resulting from the substitution position of Ar. "m" is preferably an integer of 1 to 4.]

[0053] The perylene compound is a compound having a structure in which two oxygen atoms constituting a six-membered ring of perylene tetracarboxylic dianhydride are removed, and examples thereof include perylene black.

[0054] The content of one or more compounds selected from azomethine azo compounds and perylene compounds in the core layer varies depending on the thickness of the core layer and the composition of the pattern layer described later, and therefore cannot be generalized. It is preferably less than 45% by mass of the total solid content constituting the core layer, and more preferably 5% to 30% by mass.

[0055] The core layer may contain additives such as ultraviolet absorbers, light stabilizers, antioxidants and flame retardants as needed.

[0056] The thickness of the core layer is not particularly limited, but is usually 1 mm or more, preferably 1 mm to 10 mm.

[0057] In this specification, the thickness of each layer (core layer, pattern layer, etc.) constituting the resin panel is calculated as an average value of 20 arbitrary points when a vertical cross section of the resin panel is observed using an electron microscope or the like.

[0058] <Anti-reflection layer>

[0059] The resin panel of the present invention is preferably provided with an anti-reflection layer on the surface of at least one side. The anti-reflection layer is preferably provided at least on the surface of the inner layer side of the resin panel, and may also be provided on the surfaces of both sides of the resin panel. It should be noted that, if the outer layer side of the resin panel is required to have excellent scratch resistance, it is also preferred to provide the anti-reflection layer only on the surface of the inner layer side of the resin panel.

[0060] It should be noted that a general antireflection layer is designed so that the reflectance is lowest near the center wavelength of 550 nm in the visible light region. The antireflection layer of the present embodiment preferably has the lowest reflectance near the wavelength of 905 nm.

[0061] The anti-reflection layer may include, for example, a single-layer structure of a low-refractive index layer, a two-layer structure of a high-refractive index layer and a low-refractive index layer, and may further include three or more layers of the anti-reflection layer. In the case of a two-layer structure of a high-refractive index layer and a low-refractive index layer, the low-refractive index layer is disposed on the surface side (= with the high-refractive index layer as the core layer side).

[0062] The total thickness of the antireflection layer is adjusted so that the reflectivity near the wavelength of 905 nm is reduced for various antireflection layer structures (single layer, two layers, three layers or more). The total thickness of the antireflection layer is, for example, about 120 nm to 550 nm, preferably about 170 nm to 450 nm.

[0063] - Low refractive index layer -

[0064] The refractive index of the low refractive index layer is preferably 1.28 to 1.40, more preferably 1.30 to 1.38, and even more preferably 1.32 to 1.37.

[0065] The thickness of the low refractive index layer is preferably 120 nm to 250 nm, more preferably 120 nm to 200 nm, further preferably 150 nm to 200 nm, and further preferably 160 nm to 190 nm.

[0066] By setting the refractive index and thickness of the low refractive index layer to be within the above ranges, the reflectivity at a wavelength of around 905 nm can be easily minimized.

[0067] The method of forming a low refractive index layer can be roughly divided into a wet method and a dry method. As a wet method, there can be mentioned: a method of forming by a sol-gel method using a metal alkoxide or the like; a method of forming by coating a low refractive index resin such as a fluororesin; a method of forming by coating a low refractive index layer forming coating liquid containing low refractive index particles in a resin composition. As a dry method, there can be mentioned the following method: selecting particles having a desired refractive index from the low refractive index particles described later, and forming by a physical vapor growth method or a chemical vapor growth method.

[0068] The wet method is excellent from the viewpoint of production efficiency. In the wet method, it is preferable to form the layer using a coating liquid for forming a low refractive index layer containing low refractive index particles in the binder resin composition.

[0069] The low refractive index particles may be any of particles composed of inorganic compounds such as silicon dioxide and magnesium fluoride or particles composed of organic compounds, and may be used without limitation. However, particles having a structure with voids are preferably used from the perspective of improving antireflection properties by lowering the refractive index.

[0070] The particles having a structure with voids have fine voids inside, for example, they are filled with a gas such as air having a refractive index of 1.0, so their own refractive index is low. As such particles having voids, inorganic or organic porous particles, hollow particles, etc. can be cited, for example, porous polymer particles or hollow polymer particles using porous silica, hollow silica particles, or acrylic resins, etc. can be cited.

[0071] The average particle size of the primary particles of the low refractive index particles is preferably 5 nm to 200 nm, more preferably 5 nm to 100 nm, and further preferably 10 nm to 80 nm.

[0072] The content of the low refractive index particles is preferably 50 to 200 parts by mass, more preferably 70 to 150 parts by mass, based on 100 parts by mass of the binder component.

[0073] The binder resin composition is preferably a curable resin composition. The curable resin composition becomes a cured product in the antireflection layer and serves as a binder component.

[0074] Examples of the curable resin composition include thermosetting resin compositions and ionizing radiation curable resin compositions. Among these, ionizing radiation curable resin compositions are preferred.

[0075] Thermosetting resin composition is a composition containing at least a thermosetting resin, and is a resin composition that is cured by heating. Examples of thermosetting resins include acrylic resins, urethane resins, phenolic resins, urea-melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. In the thermosetting resin composition, a curing agent such as an isocyanate curing agent is added to these curable resins as needed.

[0076] The ionizing radiation curable resin composition is a composition containing a compound having an ionizing radiation curable functional group (hereinafter also referred to as an "ionizing radiation curable compound"). Examples of the ionizing radiation curable functional group include ethylenically unsaturated bond groups such as (meth)acryloyl, vinyl, and allyl groups, as well as epoxy groups and oxetanyl groups.

[0077] As the ionizing radiation curable resin, a compound having an ethylenically unsaturated bond group is preferred. In addition, from the aspect of suppressing damage to the resin layer during the process of manufacturing the transfer sheet, as the ionizing radiation curable resin, a compound having two or more ethylenically unsaturated bond groups is more preferred, and among them, a multifunctional (meth) acrylate compound having two or more ethylenically unsaturated bond groups is further preferred. As the multifunctional (meth) acrylate compound, both a monomer and an oligomer can be used.

[0078] It should be noted that ionizing radiation refers to radiation in electromagnetic waves or charged particle beams that has energy quanta that can cause molecules to polymerize or cross-link. Usually, ultraviolet light (UV) or electron beam (EB) are used. In addition, electromagnetic waves such as X-rays and gamma rays, alpha rays, and charged particle beams such as ion beams can also be used.

[0079] Examples of the bifunctional (meth)acrylate monomer in the polyfunctional (meth)acrylate compound include ethylene glycol di(meth)acrylate, bisphenol A tetraethoxy diacrylate, bisphenol A tetrapropoxy diacrylate, and 1,6-hexanediol diacrylate.

[0080] Examples of the trifunctional or higher-functional (meth)acrylate monomer include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and isocyanuric acid-modified tri(meth)acrylate.

[0081] The (meth)acrylate monomers may have a part of their molecular skeleton modified, and those modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol, or the like may also be used.

[0082] Examples of the polyfunctional (meth)acrylate oligomer include acrylate polymers such as urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate.

[0083] Urethane (meth)acrylate is obtained, for example, by reaction of polyol and organic diisocyanate with hydroxy (meth)acrylate.

[0084] In addition, preferred epoxy (meth)acrylates are (meth)acrylates obtained by reacting trifunctional or higher aromatic epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, etc. with (meth)acrylic acid; (meth)acrylates obtained by reacting difunctional or higher aromatic epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, etc. with polybasic acids and (meth)acrylic acid; and (meth)acrylates obtained by reacting difunctional or higher aromatic epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, etc. with phenols and (meth)acrylic acid.

[0085] The above-mentioned ionizing radiation curable resins may be used alone or in combination of two or more.

[0086] When the ionizing radiation curable resin is an ultraviolet curable resin, the coating liquid for forming a resin layer preferably contains additives such as a photopolymerization initiator and a photopolymerization accelerator.

[0087] Examples of the photopolymerization initiator include one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzoin dimethyl ether, benzoylbenzoate, α-acyl oxime ester, thioxanthones and the like.

[0088] The photopolymerization accelerator can reduce polymerization inhibition by air during curing and increase the curing rate, and examples thereof include at least one selected from isopentyl p-dimethylaminobenzoate, ethyl p-dimethylaminobenzoate, and the like.

[0089] The low refractive index layer preferably contains a water repellent. By making the low refractive index layer contain a water repellent, condensation inside the resin panel can be suppressed, and the reduction in the function of the infrared sensor due to condensation can be suppressed.

[0090] Examples of the water repellent include fluorine compounds, and the content of the water repellent is preferably 1% to 30% by mass, more preferably 3% to 20% by mass, of the total solid content of the low refractive index layer.

[0091] -High refractive index layer-

[0092] The anti-reflection layer may further include a high refractive index layer. By including a high refractive index layer in addition to the low refractive index layer, the wavelength region with low reflectivity is expanded, and the applicable range of the wavelength of the infrared laser can be expanded. In addition, the peak of the reflectivity near 905nm can be made sharp, and by increasing the reflectivity of other wavelengths, other wavelengths that become noise can be cut off.

[0093] The high refractive index layer is disposed closer to the core layer than the low refractive index layer.

[0094] The refractive index of the high refractive index layer is preferably 1.55 to 1.85, more preferably 1.56 to 1.70.

[0095] The thickness of the high refractive index layer is preferably 300 nm or less, more preferably 20 nm to 250 nm.

[0096] The high refractive index layer can be formed of, for example, a high refractive index layer coating liquid containing a binder resin composition and high refractive index particles. As the binder resin composition, for example, the curable resin composition exemplified in the low refractive index layer can be used.

[0097] Examples of high refractive index particles include antimony pentoxide (1.79), zinc oxide (1.90), titanium oxide (2.3-2.7), cerium oxide (1.95), tin-doped indium oxide (1.95-2.00), antimony-doped tin oxide (1.75-1.85), yttrium oxide (1.87) and zirconium oxide (2.10).

[0098] The average particle size of the primary particles of the high refractive index particles is preferably 5 nm to 200 nm, more preferably 5 nm to 100 nm, and even more preferably 10 nm to 80 nm.

[0099] -Contact angle-

[0100] The water contact angle of the antireflection layer surface is preferably 100 degrees or more, more preferably 105 degrees or more. By setting the contact angle within this range, condensation inside the resin panel can be suppressed, and the reduction in the function of the infrared sensor due to condensation can be suppressed.

[0101] In this specification, the term "water contact angle" refers to a value obtained by dropping 1.5 μL of pure water and measuring the static contact angle 2 seconds after the droplet adheres according to the θ / 2 method.

[0102] <Other layer 1 (layer located between the core layer and the antireflection layer)>

[0103] The core layer and the antireflection layer may be directly in close contact with each other, but are preferably in close contact with each other through another layer.

[0104] Examples of the layer between the core layer and the antireflection layer include a substrate A, an adhesive layer A, and a hard coat layer A. In addition, other layers such as the pattern layer and primer layer exemplified as the outer layer may be present between the core layer and the antireflection layer.

[0105] like Figure 1 and Figure 4 As shown, when there is a substrate A (22) and an adhesive layer A (21) between the anti-reflection layer (23) and the core layer (10) (≒when there is an adhesive layer A (21) and a substrate A (22) as the inner layer (20)), it is preferred to laminate the inner layer (20) on the core layer (10) to make the core layer and the inner layer tightly bonded.

[0106] like Figure 2 and Figure 5 As shown, when there is a substrate A (22) between the anti-reflection layer (23) and the core layer (10) (≒when the inner layer (20) has a substrate A (22) but does not have an adhesive layer A (21)), it is preferred to seal the core layer (10) and the inner layer (20) by insert molding.

[0107] like Figure 3 As shown, in the case where there is an adhesive layer A (21) between the anti-reflection layer (23) and the core layer (10) (≒ in the case where the inner layer (20) has the adhesive layer A (21) but does not have the substrate A (22)), it is preferred to bond the core layer (10) and the inner layer (20) together by in-mold molding using a transfer sheet (a transfer sheet having a transfer layer (inner layer) including an anti-reflection layer and an adhesive layer A on a release substrate).

[0108] -Substrate A-

[0109] Examples of the substrate A include plastic films composed of polyolefin resins such as polyethylene and polypropylene, vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene / vinyl acetate copolymers, and ethylene / vinyl alcohol copolymers, polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate, acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate, styrene resins such as polystyrene, and polyamide resins represented by nylon 6 or nylon 66.

[0110] Among these plastic films, biaxially oriented polyester films are preferred from the perspective of heat resistance and dimensional stability, and acrylic films, polycarbonate films, or coextruded products of acrylic and polycarbonate are preferred from the perspective of moldability in insert molding and weather resistance.

[0111] The thickness of the substrate A is preferably 28 μm to 250 μm, more preferably 38 μm to 200 μm, from the viewpoints of moldability and handling properties.

[0112] - Adhesive layer A -

[0113] The adhesive layer A is preferably disposed at a position in contact with the core layer.

[0114] The adhesive layer A may be a pressure-sensitive adhesive layer (so-called "adhesive layer") or a heat-sensitive adhesive layer (so-called "heat-sealing layer"). In the case of lamination, a pressure-sensitive adhesive layer (adhesive layer) is preferred, and in the case of in-mold molding, a heat-sensitive adhesive layer (heat-sealing layer) is preferred.

[0115] In addition, the adhesive layer A preferably uses a heat-sensitive or pressure-sensitive resin suitable for the material of the core layer. For example, when the material of the core layer is an acrylic resin, it is preferred to use an acrylic resin. In addition, when the material of the core layer is a polyphenylene ether resin, a polycarbonate resin, or a styrene resin, it is preferred to use an acrylic resin, a polystyrene resin, a polyamide resin, etc. having affinity with these resins. In addition, when the material of the core layer is a polypropylene resin, it is preferred to use a chlorinated polyolefin resin, a vinyl chloride-vinyl acetate copolymer resin, a cyclized rubber, or a benzofuran indene resin.

[0116] The thickness of the adhesive layer A is preferably 0.1 μm to 50 μm, more preferably 0.5 μm to 30 μm.

[0117] -Hard Coating A-

[0118] The hard coat layer A is preferably disposed closer to the core layer than the antireflection layer and in contact with the antireflection layer.

[0119] By arranging the hard coating layer A at the above position, it is possible to suppress the surface of the anti-reflection layer from being damaged during the manufacture of the resin panel and when the resin panel is assembled to the infrared sensor, and it is possible to easily maintain the desired transmittance for a long time. In addition, by arranging the hard coating layer A at the above position, it is possible to further improve the infrared transmittance by adjusting the refractive index of the hard coating layer A.

[0120] The hard coat layer A preferably contains a cured product of a curable resin composition as a main component.

[0121] The main component refers to 50% by mass or more of the total solid content constituting the hard coat layer A, preferably 70% by mass or more, and more preferably 80% by mass or more.

[0122] Examples of the curable resin composition of the hard coat layer A include thermosetting resin compositions and ionizing radiation curable resin compositions, and ionizing radiation curable resin compositions are preferred.

[0123] Examples of the thermosetting resin composition and ionizing radiation curable resin composition of the hard coat layer A include the same ones as those of the low refractive index layer.

[0124] In order to increase the hardness, the hard coating layer A may contain inorganic particles.

[0125] Examples of the inorganic particles include silica, alumina, zirconia, and titania, and silica is preferred.

[0126] The average particle size of the inorganic particles is preferably 10 nm to 6 μm, more preferably 30 nm to 5 μm.

[0127] In this specification, the average particle size is measured as a mass average particle size d50 in a particle size distribution measurement by a laser diffraction method.

[0128] The content of the inorganic particles in the hard coat layer A is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, based on 100 parts by mass of the cured product of the curable resin composition.

[0129] The thickness of the hard coat layer A is preferably 1 μm to 20 μm, more preferably 2 μm to 10 μm, and even more preferably 3 μm to 5 μm.

[0130] <Pattern Layer>

[0131] The resin panel of the present invention may have a pattern layer.

[0132] When the resin panel has an antireflection layer, the pattern layer is preferably located between the antireflection layer and the core layer or on the opposite side of the core layer from the antireflection layer, and more preferably located on the opposite side of the core layer from the antireflection layer.

[0133] That is, in the embodiment having the antireflection layer and the pattern layer, the resin panel more preferably has the pattern layer, the core layer and the antireflection layer in this order, and the antireflection layer is disposed on the surface of the resin panel.

[0134] The pattern layer preferably contains a binder resin and a colorant.

[0135] As the binder resin of the pattern layer, a cured product of a thermoplastic resin, a thermosetting resin composition and a cured product of an ionizing radiation curable resin composition can be cited. From the aspect of improving the adhesion with the adjacent layer (for example, substrate B, primer, hard coat B), it is preferably appropriately selected according to the composition of the adjacent layer. For example, if a thermoplastic resin is included as the binder resin, it is preferred from the aspect of easily improving the adhesion with various layers. In addition, in the case where the adjacent layer is formed by a thermosetting resin composition, the binder resin of the pattern layer is preferably formed by a thermosetting resin composition (when the adjacent layer includes a cured product of a thermosetting resin composition, the binder resin of the pattern layer preferably includes a cured product of a thermosetting resin composition).

[0136] Examples of the thermoplastic resin and thermosetting resin composition as the binder resin of the pattern layer include the same ones as exemplified as the thermoplastic resin of the core layer and the thermosetting resin composition of the low refractive index layer.

[0137] From the perspective of being able to maintain the transmittance at a wavelength of 905 nm in a high range, the colorant of the pattern layer is preferably one or more compounds selected from azomethine azo compounds and perylene compounds. That is, the pattern layer preferably contains one or more compounds selected from azomethine azo compounds and perylene compounds.

[0138] The content of one or more compounds selected from azomethine azo compounds and perylene compounds in the pattern layer varies depending on the thickness of the pattern layer and the composition of the above-mentioned core layer, and therefore cannot be generalized. It is preferably 5% to 50% by mass of the total solid content constituting the pattern layer, and more preferably 10% to 40% by mass.

[0139] The pattern layer may also be a single layer, preferably having a first pattern layer formed of dots or meshes and a second pattern layer that is solid on the entire surface. With this structure, the dots or meshes of the first pattern layer can be used to impart aesthetics, while the second pattern layer can be printed solid on the entire surface to impart visible light shielding properties, making it easy to take both aesthetics and visible light shielding properties into account.

[0140] In particular, by making the first pattern layer and the second pattern layer both contain one or more compounds selected from azomethine azo compounds and perylene compounds, it is possible to easily maintain the light transmittance at a wavelength of 905 nm in a high range while achieving both aesthetics and visible light shielding properties.

[0141] It is preferred that each of the dots of the first pattern layer has a diameter of 5 μm to 100 μm, and the interval between the centers of the dots is 20 μm to 200 μm.

[0142] The mesh of the first pattern layer preferably has a line width of 20 μm to 100 μm and an interval between line centers of 20 μm to 200 μm.

[0143] The thickness of the pattern layer (when the pattern layer includes the first pattern layer and the second pattern layer, the total thickness of the first pattern layer and the second pattern layer) is preferably 0.5 μm to 10 μm, more preferably 1 μm to 7 μm, and further preferably 3 μm to 5 μm.

[0144] When the pattern layer includes a first pattern layer and a second pattern layer, the ratio of the thickness of the first pattern layer to the thickness of the second pattern layer is preferably 2:8 to 8:2, more preferably 4:6 to 6:4.

[0145] <Other layer 2 (a layer located on the opposite side of the core layer from the antireflection layer)>

[0146] As described above, the pattern layer is preferably located on the side of the core layer opposite to the anti-reflection layer. It should be noted that the side of the core layer opposite to the anti-reflection layer may also have a layer other than the pattern layer. In addition, the side of the core layer opposite to the anti-reflection layer may not have a pattern layer but may have other layers (e.g. Figure 2 , 5 ). In addition, the core layer may not have a layer on the side opposite to the anti-reflection layer, and the core layer may be exposed (for example Figure 6 ).

[0147] Examples of the layer other than the pattern layer located on the opposite side of the core layer to the antireflection layer include a substrate B, an adhesive layer B, a primer layer, and a hard coat layer B.

[0148] like Figure 4 and Figure 5 As shown, when the core layer 10 has a substrate B (31) on the side opposite to the anti-reflection layer (≒when the outer layer (30) has a substrate B (31) but does not have an adhesive layer B (32)), it is preferred to seal the core layer (10) and the outer layer (30) by insert molding.

[0149] like Figure 1 to Figure 3 As shown, in the case where the core layer 10 has an adhesive layer B (32) on the side opposite to the anti-reflection layer (≒in the case where the outer layer (30) has an adhesive layer B (32) but does not have a substrate B (31)), it is preferred to bond the core layer (10) and the outer layer (30) together by in-mold molding using a transfer sheet (a transfer sheet having a transfer layer (outer layer) including an adhesive layer B on a release substrate), and then peel off the release substrate.

[0150] In addition, although not shown in the figure, when the core layer has an adhesive layer B and a substrate B on the side opposite to the anti-reflection layer (≒when the outer layer has an adhesive layer B and a substrate B), it is preferred to laminate the outer layer on the core layer to tightly bond the core layer and the outer layer.

[0151] -Substrate B-

[0152] As the substrate B, the plastic films exemplified in the substrate A can be mentioned.

[0153] Among these plastic films, biaxially oriented polyester films are preferred from the viewpoint of heat resistance and dimensional stability, and acrylic films, polycarbonate films, or coextruded films of acrylic and polycarbonate are preferred from the viewpoint of moldability in insert molding and weather resistance.

[0154] From the viewpoints of moldability, handling properties, and stone flying resistance, the thickness of the substrate B is preferably 28 μm to 300 μm, more preferably 75 μm to 250 μm.

[0155] - Adhesive layer B -

[0156] The adhesive layer B may be a pressure-sensitive adhesive layer (so-called "adhesive layer") or a heat-sensitive adhesive layer (so-called "heat-sealing layer"). In the case of lamination, a pressure-sensitive adhesive layer (adhesive layer) is preferred, and in the case of in-mold molding, a heat-sensitive adhesive layer (heat-sealing layer) is preferred.

[0157] In addition, a heat-sensitive or pressure-sensitive resin suitable for the material of the core layer is preferably used for the adhesive layer B. Preferred embodiments of the adhesive layer B according to the material of the core layer are the same as those of the adhesive layer A.

[0158] The thickness of the adhesive layer B is preferably 0.1 μm to 50 μm, more preferably 0.5 μm to 30 μm.

[0159] -Hard Coating B-

[0160] The hard coating layer B is preferably arranged on the outermost surface of the layer on the opposite side of the core layer to the anti-reflection layer. That is, the hard coating layer B is preferably arranged on the surface side of the outer layer (the side of the outer layer farthest from the core layer). By arranging the hard coating layer B at the position, the scratch resistance of the resin panel can be improved, and the function of the infrared sensor can be easily maintained for a long time.

[0161] The hard coat layer B preferably contains a cured product of a curable resin composition as a main component.

[0162] The main component refers to 50% by mass or more of the total solid content constituting the hard coat layer B, preferably 70% by mass or more, and more preferably 80% by mass or more.

[0163] Examples of the curable resin composition of the hard coat layer B include thermosetting resin compositions and ionizing radiation curable resin compositions, and ionizing radiation curable resin compositions are preferred.

[0164] Examples of the thermosetting resin composition and ionizing radiation curable resin composition of the hard coat layer B include the same ones as those of the low refractive index layer.

[0165] In order to increase the hardness, the hard coating layer B may contain inorganic particles.

[0166] The embodiments of the inorganic particles of the hard coat layer B (particle type, average particle size, content) are the same as those of the inorganic particles of the hard coat layer A.

[0167] Since the hard coating layer B is located on the outside, it preferably contains a weathering agent.

[0168] Examples of the weathering agent include general-purpose ultraviolet absorbers and light stabilizers. The content of the weathering agent is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the cured product of the curable resin composition.

[0169] The thickness of the hard coat layer B is preferably 1 μm to 20 μm, more preferably 2 μm to 10 μm, and even more preferably 3 μm to 5 μm.

[0170] -Base coating-

[0171] The primer layer is a layer disposed between the layers as needed to improve interlayer adhesion. The position of the primer layer is not particularly limited, and for example, the primer layer may be disposed between the hard coat layer B and the pattern layer.

[0172] The undercoat layer preferably contains a resin component as a main component.

[0173] Examples of the resin component of the primer layer include cured products of thermoplastic resins and curable resin compositions, preferably cured products of curable resin compositions, and more preferably cured products of thermosetting resin compositions.

[0174] Examples of the thermosetting resin composition used as the resin component of the primer include the same thermosetting resin compositions as exemplified in the low refractive index layer.

[0175] The thickness of the primer layer is preferably 1 μm to 20 μm, more preferably 2 μm to 10 μm, and even more preferably 3 μm to 5 μm.

[0176] -ATO (Antimony Tin Oxide), ITO (Indium Tin Oxide)-

[0177] The resin panel of the present invention may contain one or more infrared absorbers selected from ATO and ITO in any of the outer layers.

[0178] ATO and ITO have the following characteristics: they can transmit light with a wavelength of 905nm at a predetermined ratio, and on the other hand, they can absorb most of the near infrared rays with a wavelength exceeding 905nm. Therefore, by including one or more infrared absorbers selected from ATO and ITO in any of the outer layers, the transmittance of the wavelength of 905nm can be maintained at a high level, and on the other hand, near infrared rays with a wavelength exceeding 905nm can be cut off, thereby suppressing the temperature rise inside the infrared sensor, and making it easy to fully exert the function of the infrared sensor.

[0179] It is preferable that one or more infrared absorbers selected from ATO and ITO are contained in any one or more layers selected from the adhesive layer B, the hard coat layer B and the primer layer.

[0180] The content of one or more infrared absorbers selected from ATO and ITO may be appropriately adjusted within a range in which the light transmittance of the resin panel at a wavelength of 905 nm can be maintained at 85% or more.

[0181] It should be noted that when using cesium tungsten oxide and lanthanum hexaboride, which are representative examples of infrared absorbers, it is difficult to maintain the light transmittance at a wavelength of 905 nm at a high level.

[0182] [Manufacturing method of resin panel]

[0183] The resin panel of the present invention can be produced by, for example, lamination, insert molding, in-mold molding, or the like.

[0184] The following, Figure 1 to Figure 6 A manufacturing example of a resin panel is described below.

[0185] < Figure 1 Manufacturing example of resin panel>

[0186] Figure 1 The resin panel can be produced, for example, by the steps 1-1 to 1-5 below.

[0187] 1-1. A step of preparing a laminate film for forming an inner layer (20) having an adhesive layer A (21), a substrate A (22), a hard coat layer A (24) and an antireflection layer (23) in this order.

[0188] 1-2. A step of preparing a transfer sheet B for in-mold molding for forming an outer layer (30) which has a release substrate B (not shown), a hard coat layer B (35), a pattern layer (33) and an adhesive layer B (32) in this order.

[0189] 1-3. The transfer sheet B of 1-2 is arranged in a mold for in-mold molding (the transfer sheet B is arranged in the mold in such a way that the adhesive layer B (32) faces the inner side of the mold), and then the core layer forming composition is injected to obtain a laminate in which the core layer (10) and the adhesive layer B (32) of the transfer sheet B are tightly bonded.

[0190] 1-4. A step of peeling the release substrate B from the laminate obtained in the above 1-3.

[0191] 1-5. A step of laminating the adhesive layer A (21) side of the laminate film of 1-1 to the exposed surface of the core layer (10) of the laminate obtained in 1-3 or the laminate of 1-4 from which the release substrate B is peeled.

[0192] < Figure 2 Manufacturing example of resin panel>

[0193] Figure 2 The resin panel can be produced, for example, by the steps 2-1 to 2-5 below.

[0194] 2-1. A step of preparing an insert molding film A for forming an inner layer (20) which includes a substrate A (22), a hard coating layer A (24) and an antireflection layer (23) in this order.

[0195] 2-2. A step of preparing a transfer sheet B for in-mold molding for forming an outer layer ( 30 ) which includes a release substrate B (not shown), a hard coat layer B ( 35 ) and an adhesive layer B ( 32 ) in this order.

[0196] 2-3. A step of placing the insert molding film A of 2-1 above in a vacuum molding mold, performing vacuum molding (offline premolding), and trimming excess portions as necessary to obtain a molded sheet A.

[0197] 2-4. A process of disposing the molding sheet A obtained in the above 2-3 on one side of a pair of molds for injection molding (insert and in-mold batch molding), and disposing the transfer sheet B of the above 2-2 on the other side of the above mold, and then injecting the core layer forming composition to obtain a laminate in which the substrate A (22) of the molding sheet A, the core layer (10) and the adhesive layer B (32) of the transfer sheet B are tightly bonded.

[0198] 2-5. A step of peeling the release substrate B from the laminate obtained in the above 2-4.

[0199] < Figure 3 Manufacturing example of resin panel>

[0200] Figure 3 The resin panel can be produced, for example, by the steps 3-1 to 3-4 below.

[0201] 3-1. A step of preparing a transfer sheet A for in-mold molding for forming an inner layer (20) which has a release substrate A (not shown), an antireflection layer (23), a hard coat layer A (24) and an adhesive layer A (21) in this order.

[0202] 3-2. A step of preparing a transfer sheet B for in-mold molding for forming an outer layer (30) which has a release substrate B (not shown), a hard coat layer B (35), a pattern layer (33) and an adhesive layer B (32) in this order.

[0203] 3-3. A process of disposing the transfer sheet A of 3-1 on one side of a pair of in-mold molding molds, and disposing the transfer sheet B of 3-2 on the other side of the molds (the transfer sheet A and the transfer sheet B are arranged in the molds in such a manner that the adhesive layer A (21) and the adhesive layer B (32) face the inner side of the molds, respectively, and the adhesive layer A and the adhesive layer B are opposite to each other), and then injecting a core layer forming composition to obtain a laminate in which the adhesive layer A (21) of the transfer sheet A, the core layer (10) and the adhesive layer B (32) of the transfer sheet B are tightly bonded.

[0204] 3-4. A step of opening the mold and peeling the release substrate A and the release substrate B from the laminate obtained in the above 3-3.

[0205] < Figure 4 Manufacturing example of resin panel>

[0206] Figure 4 The resin panel can be produced, for example, by the steps 4-1 to 4-5 below.

[0207] 4-1. A step of preparing a laminate film for forming an inner layer (20) having an adhesive layer A (21), a substrate A (22) and an antireflection layer (23) in this order.

[0208] 4-2. A step of preparing an insert molding film for forming an outer layer (30) having a substrate B (31), a pattern layer (33), a primer layer (34) and a hard coat layer B (35) in this order.

[0209] 4-3. A step of placing the insert molding film of 4-2 above in a vacuum molding mold, performing vacuum molding (offline premolding), and trimming excess portions as necessary to obtain a molded sheet.

[0210] 4-4. A step of inserting the molded sheet obtained in 4-3 above into an injection molding die and injecting the core layer forming composition to obtain a laminate in which the core layer (10) and the molding sheet (outer layer) are in close contact with each other.

[0211] 4-5. A step of laminating the adhesive layer A (21) side of the laminate film of 4-1 to the surface of the laminate obtained in 4-4 above where the core layer is exposed.

[0212] < Figure 5 Manufacturing example of resin panel>

[0213] Figure 5 The resin panel can be produced, for example, by the steps 5-1 to 5-5 below.

[0214] 5-1. A step of preparing an insert molding film A for forming an inner layer (20) having a substrate A (22), a hard coating layer A (24) and an antireflection layer (23) in this order.

[0215] 5-2. A step of preparing an insert molding film B for forming an outer layer ( 30 ) having a substrate B ( 31 ), a primer layer ( 34 ), and a hard coat layer B ( 35 ) in this order.

[0216] 5-3. A step of placing the insert molding film A of 5-1 above in a vacuum molding mold, performing vacuum molding (offline premolding), and trimming excess portions as necessary to obtain a molded sheet A.

[0217] 5-4. A step of placing the insert molding film B of 5-2 above in a vacuum molding mold, performing vacuum molding (offline premolding), and trimming excess portions as necessary to obtain a molded sheet B.

[0218] 5-5. A process of disposing the molding sheet A obtained in the above 5-3 on one side of a pair of insert molding molds, and disposing the molding sheet B obtained in the above 5-4 on the other side of the above molds, and then injecting a core layer forming composition to obtain a laminate in which the molding sheet A (inner layer), the core layer (10) and the molding sheet B (outer layer) are tightly bonded.

[0219] < Figure 6 Manufacturing example of resin panel>

[0220] Figure 6 The resin panel can be produced, for example, by the steps 6-1 to 6-3 below.

[0221] 6-1. A step of preparing a laminate film for forming an inner layer (20) having an adhesive layer A (21), a substrate A (22) and an antireflection layer (23) in this order.

[0222] 6-2. Step of preparing a molded core layer (10).

[0223] 6-3. A step of bonding the adhesive layer A (21) side of the laminate film of 6-1 above to the core layer.

[0224] [Infrared sensor]

[0225] The infrared sensor of the present invention comprises an infrared light emitting element, an infrared light receiving element, and a protective cover arranged in front of the infrared light emitting element and the infrared light receiving element, wherein the protective cover is the resin panel of the present invention.

[0226] The infrared light emitting element can be used without particular limitation as long as it emits infrared laser light. The wavelength of the infrared laser light is preferably 905 nm.

[0227] In addition, any infrared light receiving element can be used without particular limitation as long as it can receive the above-mentioned infrared laser light.

[0228] The infrared light emitting element and the infrared light receiving element are preferably disposed in the housing.

[0229] The housing preferably has a window portion, through which infrared rays can be irradiated and received. In addition, a protective cover is preferably provided on the window portion.

[0230] The protective cover is arranged in front of the infrared light emitting element and the infrared light receiving element. The infrared sensor of the present invention needs to use the above-mentioned resin panel of the present invention as a protective cover.

[0231] By using the resin panel of the present invention as a protective cover, the infrared sensor is less likely to have an operational error, and the infrared sensor can fully function.

[0232] When the resin panel has an antireflection layer, it is preferable to arrange the resin panel so that the side having the antireflection layer faces the infrared light emitting element and the infrared light receiving element.

[0233] Infrared sensors are useful as distance sensors (LiDAR), and can be used as sensors for automobile driving, for example.

[0234] Example

[0235] Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. It should be noted that the present invention is not limited to the embodiments described in the Examples.

[0236] 1. Measurement and evaluation

[0237] The following measurements and evaluations were performed on the resin panels obtained in Examples and Comparative Examples.

[0238] 1-1. Transmittance

[0239] The transmittance (infrared transmittance) and visible light transmittance of the resin panel at a wavelength of 905 nm were measured using an ultraviolet-visible spectrophotometer having the following functions and specifications. It should be noted that for Examples 1 to 4 and Comparative Example 3, the measurements were performed in both cases where the inner side (the side with the antireflection layer) was the light incident surface and the outer side was the light incident surface.

[0240] <Functions and specifications>

[0241] Model: UV-visible spectrophotometer manufactured by JASCO Corporation (model: V-670)

[0242] Accessory unit: Integrating sphere unit (manufactured by JASCO Corporation, product number: ISN-723)

[0243] Light source: Deuterium lamp (190nm~350nm), halogen lamp (330nm~2700nm)

[0244] ·Measurement wavelength interval: 1nm

[0245] ·Diameter of measuring point: 2mm~20mm

[0246] 1-2. Scratch resistance

[0247] The outer side surfaces (the surface opposite to the side having the antireflection layer) of the resin panels of Examples 1 to 4 and Comparative Example 3, and the exposed surface of the core layer of the resin panels of Comparative Examples 1 and 2 were heated to 100 g / m 2 Steel wool ("Bonster #0000", manufactured by Nippon Steel Wool Co., Ltd.) was moved back and forth 100 times with a load of 10 ...

[0248] <Evaluation criteria for scratch resistance>

[0249] A: Average score is 2.5 or above

[0250] B: Average score is 2.0 or more and less than 2.5

[0251] C: Average score less than 2.0

[0252] 2. Preparation of coating solution

[0253] The following coating liquid was prepared. It should be noted that "parts" and "%" are based on mass.

[0254] <Hard coat coating liquid 1>

[0255] · 100 parts of urethane acrylate UV curable resin composition

[0256] (Solid content 35%, toluene / ethyl acetate mixed solvent)

[0257] ·1.5 parts of photopolymerization initiator

[0258] (IGM Resins BV, trade name "Omnirad 184")

[0259] <Hard Coating Liquid 2 (Electron Beam Curing Type)>

[0260] · 100 parts of urethane acrylate UV curable resin composition

[0261] (Solid content 35%, toluene / ethyl acetate mixed solvent)

[0262] ·Silica particles 5 parts

[0263] (Average particle size: 3 μm)

[0264] ·3 parts of weathering agent

[0265] (Manufactured by BASF, product number: Tinuvin 479)

[0266] <Laminate 1 for forming adhesive layer (adhesive layer)>

[0267] A laminate having separators on both sides of a transparent adhesive layer having a thickness of 25 μm (manufactured by Panac, trade name: Panaclean PD-S1) was prepared.

[0268] <Adhesive layer (heat seal layer) coating liquid 2>

[0269] ·Acrylic resin 100 parts

[0270] (Trade name: TM-R600(NT)K3, manufactured by Dainichi Seika Industries, solid content: 20%)

[0271] · Appropriate amount of dilution solvent

[0272] (Methyl Ethyl Ketone, Toluene)

[0273] <Low refractive index layer coating liquid 1>

[0274] 1.0 part of UV curable compound

[0275] (Trifunctional to tetrafunctional alkoxylated pentaerythritol acrylate, manufactured by Nippon Kayaku Co., Ltd., trade name "PET-30")

[0276] · Photopolymerization initiator 0.07 parts

[0277] (IGM Resins BV, trade name "Omnirad 127")

[0278] ·1.1 parts of hollow silica

[0279] (average particle size 60nm)

[0280] 0.1 part of fluorine-based antifouling agent (active ingredient: 0.005 parts by mass)

[0281] (Shin-Etsu Chemical Co., Ltd., trade name "X-71-1203M")

[0282] · Appropriate amount of dilution solvent

[0283] <Pattern layer coating liquid 1 (common to the first and second pattern layers)>

[0284] ·100 parts by mass of binder resin

[0285] (Acrylic urethane resin)

[0286] ·20 parts by mass of azomethine azo compound

[0287] (Black pigment, manufactured by Dainichi Seika Industries, trade name: Chromofine Black A1103)

[0288] · Appropriate amount of dilution solvent

[0289] <Pattern layer coating liquid 2 (common to the first and second pattern layers)>

[0290] ·100 parts by mass of binder resin

[0291] (Acrylic urethane resin)

[0292] ·40 parts by mass of azomethine azo compound

[0293] (Black pigment, manufactured by Dainichi Seika Industries, trade name: Chromofine Black A1103)

[0294] · Appropriate amount of dilution solvent

[0295] <Undercoat coating liquid 1>

[0296] ·Acrylic polyol 100 parts

[0297] (Manufactured by Dainichi Seika Industries, Ltd., trade name: TM-VMAC)

[0298] ·1 part of isocyanate compound

[0299] (Manufactured by Dainichi Seika Industries, Ltd., trade name: RC-3 Curing Agent)

[0300] · Appropriate amount of dilution solvent

[0301] 3. Production of molding materials

[0302] 3-1.Laminating film

[0303] The coating solution 1 for hard coating was applied to a polyethylene terephthalate film having a thickness of 50 μm so that the thickness after drying was 4 μm, and then dried and irradiated with ultraviolet light to form a hard coating layer A. Next, the coating solution 1 for low refractive index layer was applied to the hard coating layer A so that the thickness after drying was 175 nm, and then dried and irradiated with ultraviolet light to form a single-layer antireflection layer of the low refractive index layer. Next, one separator of the above-mentioned laminate 1 was peeled off and attached to the surface of the polyethylene terephthalate film on the opposite side to the hard coating layer, and then the other separator of the laminate 1 was peeled off to obtain a laminated film having an adhesive layer A (adhesive layer), a substrate A (polyethylene terephthalate film), a hard coating layer A and an antireflection layer (a single layer of a low refractive index layer) in this order.

[0304] The refractive index of the low refractive index layer derived from the low refractive index layer coating liquid 1 was 1.36.

[0305] 3-2. Film for insert molding

[0306] The insert molding film was obtained in the same manner as in 3-1 except that the 50 μm thick polyethylene terephthalate film was changed to a 125 μm thick acrylic film and that the adhesive layer A (adhesive layer) was not formed. The insert molding film had a substrate A (acrylic film), a hard coating layer A, and an antireflection layer (a single layer of a low refractive index layer) in this order.

[0307] 3-3. Transfer sheet 1 for in-mold molding

[0308] The coating liquid 1 for the low refractive index layer was applied to a 50 μm thick polyethylene terephthalate film (release substrate A) with release properties so that the thickness after drying was 175 nm, and dried and irradiated with ultraviolet light to form a single-layer antireflection layer of the low refractive index layer. Next, the coating liquid 1 for the hard coating was applied to the low refractive index layer so that the thickness after drying was 4 μm, dried and irradiated with ultraviolet light to form a hard coating layer A. Next, the coating liquid 2 for the adhesive layer (heat seal layer) was applied to the hard coating layer A so that the thickness after drying was 2 μm, and dried to form an adhesive layer A with heat sealability, thereby obtaining a transfer sheet 1 for in-mold molding.

[0309] The transfer sheet 1 includes a release substrate A, an antireflection layer (a single layer of a low refractive index layer), a hard coat layer A, and an adhesive layer A (heat seal layer) in this order.

[0310] 3-4. Transfer sheet for in-mold molding 2

[0311] The coating liquid 2 for hard coating was applied to a 50 μm thick polyethylene terephthalate film (release substrate B) having mold release properties so that the thickness after drying was 4 μm, and then dried and irradiated with electron beams to form a hard coating layer B. Next, the coating liquid 1 for pattern layer was applied to the hard coating layer B in a dot-like manner (dot diameter: 30 μm, interval between the centers of the dots: 70 μm) and dried to form a first pattern layer having a thickness of 2 μm. Next, the coating liquid 1 for pattern layer was applied to the first pattern layer in a solid form and dried to form a second pattern layer having a thickness of 2 μm. Next, the coating liquid 2 for adhesive layer (heat seal layer) was applied to the second pattern layer so that the thickness after drying was 2 μm and dried to form an adhesive layer B having heat seal properties, thereby obtaining a transfer sheet 2 for in-mold molding.

[0312] The transfer sheet 2 includes a release substrate B, a hard coat layer B, a pattern layer, and an adhesive layer B (heat seal layer) in this order.

[0313] 3-5. Transfer sheet for in-mold molding 3

[0314] The transfer sheet 3 for in-mold molding was obtained in the same manner as in 3-4 except that the pattern layer was not formed. The transfer sheet 3 has a release substrate B, a hard coat layer B, and an adhesive layer B (heat seal layer) in this order.

[0315] 3-6. Transfer sheet for in-mold molding 4

[0316] The transfer sheet 4 for in-mold molding was obtained in the same manner as 3-4 except that the coating liquid 1 for the pattern layer was changed to the coating liquid 2 for the pattern layer, and the thickness of the first pattern layer and the second pattern layer was changed from 2 μm to 3 μm. The transfer sheet 4 sequentially comprises a release substrate B, a hard coating layer B, a pattern layer and an adhesive layer B (heat seal layer).

[0317] 4. Production of resin panels

[0318] [Example 1]

[0319] The transfer sheet 2 of 3-4 above is placed in a mold for in-mold molding (the transfer sheet 2 is placed in the mold so that the adhesive layer B faces the inside of the mold).

[0320] Next, the molds are closed and a core layer forming composition (a composition containing 30 parts by mass of an azomethine azo compound relative to 100 parts by mass of a polycarbonate resin. The product name is "Makrolon AX2675ST", color number: 978001" manufactured by Covestro) is injected into the mold to obtain a laminate in which the core layer (thickness 4.0 mm) is tightly bonded to the adhesive layer B side of the above-mentioned transfer sheet 2.

[0321] Next, the release substrate B is peeled from the laminate.

[0322] Next, the adhesive layer A side of the laminate film of 3-1 was bonded to the exposed surface of the core layer of the laminate to obtain the resin panel of Example 1. The resin panel of Example 1 has Figure 1 The layer composition shown.

[0323] [Example 2]

[0324] The insert molding film of 2-1 is placed in a vacuum molding die, vacuum molding is performed (offline premolding), and excess portions are trimmed to obtain a molded sheet 1.

[0325] Next, the molding sheet 1 is arranged on one side of a pair of injection molding (insert and in-mold batch molding) molds, and the transfer sheet 3 of 3-5 is arranged on the other side of the mold (the transfer sheet 3 is arranged in the mold with the adhesive layer B facing the inside of the mold).

[0326] Next, the molds are closed and a core layer forming composition (a composition containing 30 parts by mass of an azomethine azo compound relative to 100 parts by mass of a polycarbonate resin. The product name is "Makrolon AX2675ST", color number: 978001" manufactured by Covestro) is injected into the mold to obtain a laminate in which the adhesive layer A of the molding sheet 1, the core layer (thickness 4.0 mm) and the adhesive layer B of the transfer sheet 3 are tightly bonded.

[0327] Next, the release substrate B was peeled off from the laminate to obtain the resin panel of Example 2. The resin panel of Example 2 has Figure 2 The layer composition shown.

[0328] [Example 3]

[0329] The transfer sheet 1 of 3-3 is arranged on one side of an upper and lower pair of in-mold molding molds, and the transfer sheet 4 of 3-6 is arranged on the other side of the above-mentioned mold (the transfer sheet 1 and the transfer sheet 4 are arranged in the mold in such a way that the adhesive layer A and the adhesive layer B face the inside of the mold respectively, and the adhesive layer A and the adhesive layer B face each other).

[0330] Next, the molds are closed and a core layer forming composition (transparent polycarbonate resin) is injected into the mold to obtain a laminate in which the adhesive layer A of the transfer sheet 1, the core layer (transparent core layer, thickness 4.0 mm) and the adhesive layer B of the transfer sheet 4 are tightly bonded.

[0331] Next, the release substrate A and the release substrate B were peeled off from the laminate to obtain a resin panel of Example 3. The resin panel of Example 3 has Figure 3 The layer composition shown.

[0332] [Example 4]

[0333] A core layer was prepared by molding a composition containing 30 parts by mass of an azomethine azo compound based on 100 parts by mass of a polycarbonate resin (trade name "Makrolon AX2675ST, color number: 978001" manufactured by Covestro Corporation) into a plate-like shape having a thickness of 4.0 mm.

[0334] The adhesive layer A side of the laminate film of 3-1 was bonded to the core layer to obtain a resin panel of Example 4. The resin panel of Example 4 has Figure 6 The layer composition shown.

[0335] [Comparative Example 1]

[0336] As the resin panel of Comparative Example 1, a composition containing 30 parts by mass of an azomethine azo compound per 100 parts by mass of a polycarbonate resin (trade name "Makrolon AX2675ST, color number: 978001" manufactured by Covestro Corporation) was molded into a plate-like shape having a thickness of 4.0 mm.

[0337] [Comparative Example 2]

[0338] As the resin panel of Comparative Example 2, a transparent polycarbonate resin plate having a thickness of 4.0 mm was prepared.

[0339] [Comparative Example 3]

[0340] A resin panel of Comparative Example 3 was obtained in the same manner as in Example 2 except that the azomethine azo compound was removed from the core layer forming composition. The resin panel of Comparative Example 3 was the same as the resin panel of Example 2 except that the core layer did not contain the azomethine azo compound and was transparent.

[0341] [Table 1]

[0342] Table 1

[0343]

[0344] Note: Regarding the infrared transmittance and visible light transmittance of Examples 1 to 4 and Comparative Example 3, the upper layer is the one with the outer side as the light entrance.

[0345] The lower layer is the value when the inner side (the side with the antireflection layer) is the light incident surface.

[0346] From Table 1, it can be confirmed that the resin panel of the example can suppress the visible light transmittance to a low level and can maintain the infrared transmittance at a high level, and when used as a protective cover for an infrared sensor, the infrared sensor can fully function.

[0347] Explanation of symbols

[0348] 10: Core layer

[0349] 20: Inner layer

[0350] 21: Adhesive layer A

[0351] 22: Base material A

[0352] 23: Anti-reflective layer

[0353] 24: Hard coating A

[0354] 30: Outer layer

[0355] 31: Base material B

[0356] 32: Adhesive layer B

[0357] 33: Pattern layer

[0358] 33A: First pattern layer

[0359] 33B: Second pattern layer

[0360] 34: Base coating

[0361] 35: Hard coating B

[0362] 100: Resin panel

Claims

1. An infrared sensor comprising an infrared light emitting element, an infrared light receiving element, and a protective cover disposed in front of the infrared light emitting element and the infrared light receiving element, wherein the protective cover is a resin panel having at least a core layer, The resin panel is provided with an anti-reflection layer on at least one surface thereof, the resin panel being arranged in such a manner that the anti-reflection layer is located on the infrared light emitting element and the infrared light receiving element side, and the water contact angle on the surface of the anti-reflection layer is greater than 100 degrees, The light transmittance of the resin panel at a wavelength of 905 nm is greater than 85%, and the visible light transmittance is less than 20%.

2. The infrared sensor according to claim 1, wherein: The core layer includes a polycarbonate resin.

3. The infrared sensor according to claim 1 or 2, wherein: The core layer includes one or more compounds selected from azomethine azo compounds and perylene compounds.

4. The infrared sensor according to claim 1 or 2, wherein: The anti-reflection layer is designed so that the reflectivity at a wavelength of 905 nm is lower than the reflectivity at a wavelength of 550 nm.

5. The infrared sensor according to claim 4, wherein: The antireflection layer has a low refractive index layer on the surface side. The low refractive index layer has a refractive index of 1.28 to 1.40 and a thickness of 120 nm to 250 nm.

6. The infrared sensor according to claim 5, wherein: The antireflection layer includes a high refractive index layer on the core layer side of the low refractive index layer, wherein the high refractive index layer has a refractive index of 1.55 to 1.85 and a thickness of 20 nm to 300 nm.

7. The infrared sensor according to claim 1 or 2, wherein: The resin panel has a pattern layer. 8 . The infrared sensor according to claim 7 , wherein the resin panel comprises the pattern layer, the core layer, and an anti-reflection layer in this order, and the anti-reflection layer is disposed on a surface of the resin panel.

9. The infrared sensor according to claim 7, wherein: The pattern layer includes a first pattern layer formed of dots or meshes and a second pattern layer that is solid on the entire surface.

10. The infrared sensor according to claim 8, wherein: The pattern layer includes a first pattern layer formed of dots or meshes and a second pattern layer that is solid on the entire surface.

11. The infrared sensor according to claim 7, wherein: The pattern layer includes at least one compound selected from azomethine azo compounds and perylene compounds.

12. The infrared sensor according to claim 8, wherein: The pattern layer includes at least one compound selected from azomethine azo compounds and perylene compounds.

13. The infrared sensor according to claim 9, wherein: The pattern layer includes at least one compound selected from azomethine azo compounds and perylene compounds.

14. The infrared sensor according to claim 10, wherein: The pattern layer includes at least one compound selected from azomethine azo compounds and perylene compounds.

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