Multilayer body and head-up display dust-proofing cover

Abstract

Provided are: a multilayer body; and a head-up display dust-proofing cover using the same. This multilayer body includes a base material layer and an infrared absorption layer. The infrared absorption layer contains an ultraviolet curable resin, two or more coloring agents, and a photopolymerization initiator. The coloring agents include tungsten oxide and a dye.

Description

Multilayer body and dustproof cover for head-up display

[0001] The present invention relates to a multilayer body and a dustproof cover for a head-up display, and more particularly to a multilayer body having a polycarbonate resin layer and an acrylic resin layer.

[0002] Polycarbonate resin is widely used in a variety of fields, not only because of its excellent transparency, but also because it is easier to process and has better impact resistance than glass, and because it does not emit toxic gases compared to other plastic materials. It is also used as a thermoforming material for vacuum forming, pressure forming, and other processes.

[0003] On the other hand, polycarbonate resin generally has low surface hardness, and therefore the surface of a molded product made of polycarbonate resin tends to be easily scratched. Therefore, when polycarbonate resin is made into a film, it has been considered to form a layer containing an acrylic resin or an infrared absorbing layer (protective layer) on the surface to prevent scratches on the product surface. Such multilayer bodies are described in Patent Documents 1 and 2.

[0004] International Publication No. 2016 / 060100 International Publication No. 2021 / 215435

[0005] Here, it is common practice to blend tungsten oxide into the infrared absorption layer as described above in order to suppress transmission of near-infrared rays. However, a multilayer body blended with tungsten oxide may result in a bluish projected image. It is desirable that the projected image of the multilayer body be a black and white projected image. The present invention aims to solve this problem by providing a multilayer body that does not result in a bluish projected image, has excellent transparency, and low infrared transmittance, and a dustproof cover for a head-up display using the same.

[0006] In light of the above-mentioned problems, the present inventors have conducted research and found that the above-mentioned problems can be solved by blending a dye together with tungsten oxide in the infrared absorbing layer. Specifically, the above-mentioned problems have been solved by the following means. <1> A multilayer body having a base layer and an infrared absorbing layer, wherein the infrared absorbing layer contains an ultraviolet curable resin, two or more types of colorants, and a photopolymerization initiator, and the colorant contains tungsten oxide and a dye. <2> A multilayer body having a L ＊ a ＊ b ＊ In the color system, a ＊ value and b ＊The multilayer body according to <1>, wherein the absolute values ​​of the values ​​are each independently 2.0 or less. <3> The multilayer body according to <1> or <2>, wherein when the total light transmittance T of the multilayer body is 81% or more, the ratio T / T1 of the transmittance T1 at a wavelength of 1000 nm is 1.5 or more, and when the total light transmittance T is less than 81%, the ratio T / T1 of T1 is 2 or more. <4> The multilayer body according to any one of <1> to <3>, wherein the base layer comprises an acrylic resin layer and a polycarbonate resin layer, and the infrared absorbing layer is located on the surface of the polycarbonate resin layer opposite to the acrylic resin layer. <5> The multilayer body according to <4>, wherein the content of the metal sulfonate in at least one of the acrylic resin layer and the polycarbonate resin layer is 0.01 to 0.80 mass%. <6> The multilayer body according to <4>, wherein the content of the metal salt of sulfonate in the polycarbonate resin layer is 0.01 to 0.80% by mass. <7> The multilayer body according to any one of <1> to <6>, wherein the haze measured according to JIS K7136 is 2.0% or less. <8> The multilayer body according to any one of <1> to <7>, wherein the infrared absorbing layer contains 20% or more by mass of the tungsten oxide. <9> The multilayer body according to any one of <1> to <8>, wherein the infrared absorbing layer contains a red colorant and a yellow colorant, each in a proportion of 0.5 to 6% by mass. <10> The multilayer body according to any one of <1> to <9>, wherein the infrared absorbing layer contains a red dye and a yellow dye, each in a proportion of 0.5 to 6% by mass. <11> The multilayer body according to any one of <1> to <10>, further comprising a hard coat layer, wherein the hard coat is formed by laminating an infrared absorbing layer, a polycarbonate resin layer, an acrylic resin layer, and a hard coat layer in this order. <12> The multilayer body according to <11>, wherein the hard coat layer contains inorganic particles. <13> The multilayer body according to any one of <1> to <12>, further comprising an antireflection layer. <14> The multilayer body according to any one of <1> to <13>, further comprising a polarizing layer. <15> A dustproof cover for a head-up display, comprising the multilayer body according to any one of <1> to <14>.

[0007] The present invention makes it possible to provide a multilayer body that does not project a bluish image, has excellent transparency, and has low infrared transmittance, as well as a dustproof cover for a head-up display that uses the same.

[0008] FIG. 1 is a schematic cross-sectional view showing an example of the multilayer body of the present invention.

[0009] Hereinafter, a detailed description of an embodiment of the present invention (hereinafter simply referred to as "the present embodiment") will be given. The following present embodiment is an example for explaining the present invention, and the present invention is not limited to this embodiment. In this specification, the term "to" is used to mean that the numerical values ​​before and after the term are included as lower and upper limits. In this specification, various physical property values ​​and characteristic values ​​are those at 23°C unless otherwise specified. In this specification, weight average molecular weights and number average molecular weights are polystyrene-equivalent values ​​measured by GPC (gel permeation chromatography) unless otherwise specified. In this specification, "(meth)acrylate" refers to both or either acrylate and methacrylate. In this specification, the term "multilayer body" includes those in the form of a film or sheet. "Film" and "sheet" refer to molded articles that are thin relative to their length and width, and are generally flat. In this specification, "film" and "sheet" may be single-layer or multi-layer. If the measurement methods and other aspects described in the standards shown in this specification vary from year to year, they will be based on the standards as of January 1, 2022, unless otherwise stated. The drawings attached to this specification are schematic diagrams and may not be to scale. In this specification, near-infrared light refers to light with a wavelength of 700 nm to 2500 nm.

[0010] The multilayer body of this embodiment has a base layer and an infrared-absorbing layer, and the infrared-absorbing layer contains an ultraviolet-curable resin, two or more colorants, and a photopolymerization initiator, and the colorant contains tungsten oxide and a dye. This configuration results in a multilayer body that does not produce a bluish projected image, has excellent transparency, and low infrared transmittance. To reduce the near-infrared transmittance of the multilayer body, it is conceivable to incorporate tungsten oxide into the infrared-absorbing layer. However, projected images of multilayer bodies incorporating tungsten oxide tend to be bluish. It is desirable for the projected image to be black and white. Therefore, it was considered to incorporate another colorant into tungsten oxide to achieve a total blackish color. However, after further investigation, the inventors found that incorporating a pigment as a colorant could adjust the color of the projected image, but resulted in poor transparency. It was speculated that this was due to the poor dispersibility of the pigment. In this embodiment, the above-mentioned problem was resolved by using a dye as at least one of the colorants. The present invention will now be described in detail.

[0011] <Infrared absorbing layer> The infrared absorbing layer in this embodiment contains an ultraviolet curable resin, two or more types of colorants, and a photopolymerization initiator, and the colorants contain tungsten oxide and a dye. By containing tungsten oxide and a dye, the total color can be adjusted to be black, thereby making it possible to produce a black and white projected image. Furthermore, by blending a dye as a colorant, it is possible to increase the dispersibility of the dye in the composition for forming an infrared absorbing layer, thereby increasing transparency. The state in which the multilayer body exhibits a black color can be determined by the L of the multilayer body. ＊ a ＊ b ＊ In the color system, a ＊ value and b ＊ The absolute values ​​of the values ​​are each independently 2.0 or less.

[0012] <<Ultraviolet Curable Resin>> The type of the ultraviolet curable resin used in this embodiment is not particularly limited, and known resins can be used. Examples of the ultraviolet curable resin include a (meth)acryloyl group-containing polymer and a polyfunctional urethane (meth)acrylate oligomer, and the polyfunctional urethane (meth)acrylate oligomer is preferred.

[0013] The (meth)acryloyl group-containing polymer can be obtained, for example, by copolymerizing (meth)acrylic acid and (meth)acrylic acid glycidyl ether to synthesize an epoxy compound having a (meth)acrylate skeleton, and then adding acrylic acid, methacrylic acid, etc. to this. A synthesis example is shown below.

[0014] The epoxy (meth)acrylate used in the (meth)acryloyl group-containing polymer includes those having a repeating unit represented by the following formula (I). In formula (I), m is an alkylene group having 1 to 4 carbon atoms or a single bond, n is an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, p is a single bond or an alkylene group having 1 or 2 carbon atoms, and q is an alkyl group having a total of 1 to 12 carbon atoms which may contain at least one substituent selected from the group consisting of an epoxy group, a hydroxyl group, an acryloyl group, and a methacryloyl group, or a hydrogen atom.

[0015] The epoxy (meth)acrylate polymer more preferably contains the following repeating unit, i.e., a repeating unit in which, in the above formula (I), m is an alkylene group having 1 or 2 carbon atoms, n is an alkyl group having 1 or 2 carbon atoms, p is a single bond or a methylene group, and q is an alkyl group having a total of 1 to 6 carbon atoms which may contain at least one substituent selected from the group consisting of a glycidyl group, a hydroxyl group, and an acryloyl group, or a hydrogen atom. For example, in the above formula (I), m is a methylene group, n is a methyl group, p is a single bond, and q is a methyl group, an alkyl group having 5 or less carbon atoms which contains a glycidyl group (epoxy group), an alkyl group having 8 or less carbon atoms which contains a hydroxyl group and an acryloyl group, or the like.

[0016] Specific examples of repeating units contained in the epoxy (meth)acrylate polymer include those represented by the following formulae (II-a), (II-b), and (II-c).

[0017] In the (meth)acrylate polymer, the repeating unit of formula (II-a) preferably accounts for 30 to 85 mol%, more preferably 40 to 80 mol%, based on the total number of moles of the repeating unit of formula (II-a), the repeating unit of formula (II-b), and the repeating unit of formula (II-c). The repeating unit of formula (II-b) preferably accounts for 5 to 30 mol%, more preferably 10 to 25 mol%, based on the total number of moles. The repeating unit of formula (II-c) preferably accounts for 10 to 40 mol%, more preferably 10 to 35 mol%, based on the total number of moles. The molar ratio of the repeating unit of formula (II-a), the repeating unit of formula (II-b), and the repeating unit of formula (II-c) is preferably 4.5 to 5.5:1.5 to 2.5:2.5 to 3.5, for example, 5:2:3.

[0018] Such (meth)acryloyl group-containing polymers are commercially available and easily available. Examples include SMP-220A (Kyoeisha Chemical Co., Ltd.), SMP-250A (Kyoeisha Chemical Co., Ltd.), SMP-360A (Kyoeisha Chemical Co., Ltd.), SMP-550A (Kyoeisha Chemical Co., Ltd.), HA7975 (Showa Denko Materials K.K.), HA7975D (Showa Denko Materials K.K.), RA-4101 (Negami Chemical Industrial Co., Ltd.), 8KX-078 (Taisei Fine Chemical Co., Ltd.), and 8KX-212 (Taisei Fine Chemical Co., Ltd.).

[0019] Examples of polyfunctional urethane (meth)acrylate oligomers include urethane reaction products of a (meth)acrylate monomer having at least one (meth)acryloyloxy group and a hydroxyl group in one molecule and a polyisocyanate; and urethane reaction products of an isocyanate compound obtained by reacting a polyol with a polyisocyanate and a (meth)acrylate monomer having at least one (meth)acryloyloxy group and a hydroxyl group in one molecule.

[0020] Examples of the (meth)acrylate monomer having at least one (meth)acryloyloxy group and one hydroxyl group per molecule, which is used in the urethanization reaction, include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glycerin di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol penta(meth)acrylate.

[0021] Examples of polyisocyanates used in the urethanization reaction include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, diisocyanates obtained by hydrogenating aromatic isocyanates among these diisocyanates (for example, diisocyanates such as hydrogenated tolylene diisocyanate and hydrogenated xylylene diisocyanate), di- or tri-polyisocyanates such as triphenylmethane triisocyanate and dimethylene triphenyl triisocyanate, and polyisocyanates obtained by polymerizing diisocyanates.

[0022] Polyols used in the urethanization reaction generally include aromatic, aliphatic, and alicyclic polyols, as well as polyester polyols, polyether polyols, etc. Typical aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, ethylene glycol, propylene glycol, trimethylolethane, trimethylolpropane, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyric acid, glycerin, and hydrogenated bisphenol A.

[0023] Examples of polyester polyols include those obtained by the dehydration condensation reaction of the above-mentioned polyols with polycarboxylic acids. Specific examples of polycarboxylic acid compounds include succinic acid, adipic acid, maleic acid, trimellitic acid, hexahydrophthalic acid, phthalic acid, isophthalic acid, and terephthalic acid. These polycarboxylic acids may be anhydrides. Examples of polyether polyols include polyalkylene glycols and polyoxyalkylene-modified polyols obtained by the reaction of the above-mentioned polyols or phenols with alkylene oxides.

[0024] Furthermore, multifunctional polyester (meth)acrylate oligomers can be obtained by a dehydration condensation reaction using (meth)acrylic acid, a polycarboxylic acid, and a polyol. Examples of polycarboxylic acids used in the dehydration condensation reaction include succinic acid, adipic acid, maleic acid, itaconic acid, trimellitic acid, pyromellitic acid, hexahydrophthalic acid, phthalic acid, isophthalic acid, and terephthalic acid. These polycarboxylic acids may also be anhydrides. Examples of polyols used in the dehydration condensation reaction include 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyric acid, trimethylolpropane, ditrimethylolpropane, pentaerythritol, and dipentaerythritol.

[0025] Polyfunctional epoxy (meth)acrylate oligomers can be obtained by the addition reaction of polyglycidyl ethers with (meth)acrylic acid. Examples of polyglycidyl ethers include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and bisphenol A diglycidyl ether.

[0026] Commercially available polyfunctional urethane (meth)acrylates can also be used, such as UN-3320HA, UN-3320HC, UN-906S, UN-901T, UN-952, UN-904, UN-905, UN-3320HS, and H-575 (all manufactured by Negami Chemical Industrial Co., Ltd.), U-6LPA and UA-1100H (all manufactured by Shin-Nakamura Chemical Co., Ltd.), and EBECRYL5129, EBECRYL4738, EBECRYL4740, EBECRYL4513, EBECRYL8254, EBECRYL220, and EBECRYL8701 (all manufactured by Daicel Allnex Corporation).

[0027] The double bond equivalent of the ultraviolet curable resin is 400 g / mol or less, preferably 360 g / mol or less, and more preferably 250 g / mol or less. By making it equal to or greater than the lower limit, the hardness of the obtained infrared absorbing layer tends to be improved. The lower limit is preferably 100 g / mol or more.

[0028] The ultraviolet curable resin preferably has 2 to 10 functional groups, and more preferably has 3 to 7 functional groups.

[0029] The weight average molecular weight of the ultraviolet curable resin is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, and even more preferably 1,000 to 30,000. By making it 1,000 or more, cure shrinkage can be more effectively suppressed, and by making it 100,000 or less, coating can be made easier.

[0030] In addition to the above, the ultraviolet-curable resin may contain a monofunctional alkyl(meth)acrylate monomer and / or a polyfunctional alkyl(meth)acrylate monomer, a styrene monomer, a styrene oligomer, a cyclic acid anhydride, an N-substituted maleimide compound, a lactone ring compound, or the like.

[0031] The content of the ultraviolet curable resin in the infrared absorbing layer of this embodiment is preferably 50% by mass or more, more preferably 55% by mass or more, and preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less, in the infrared absorbing layer (cured product). By setting the content at or above the lower limit, a multilayer body with higher toughness and hardness tends to be obtained. Furthermore, by setting the content at or below the upper limit, a coating film with a good balance between transmittance and infrared absorption can be obtained. The infrared absorbing layer of this embodiment may contain only one type of ultraviolet curable resin, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0032] <<Two or More Colorants>> The infrared absorbing layer of this embodiment contains two or more colorants, and also contains tungsten oxide and a dye.

[0033] The colorant used in this embodiment contains tungsten oxide. By containing tungsten oxide, the multilayer body can block near-infrared rays, making it more suitable for use as a dustproof cover for a head-up display. As the tungsten oxide, cesium tungsten oxide (CWO) is preferred.

[0034] The content of tungsten oxide in the infrared absorbing layer of this embodiment is preferably 20% by mass or more, more preferably 25% by mass or more, more preferably 28% by mass or more, and even more preferably 31% by mass or more, and is preferably 50% by mass or less, and more preferably 45% by mass or less. By setting the content to be equal to or greater than the lower limit, the infrared absorbing effect tends to be further improved. Furthermore, by setting the content to be equal to or less than the upper limit, excellent transparency can be maintained. The infrared absorbing layer of this embodiment may contain only one type of tungsten oxide, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0035] The colorant used in this embodiment includes a dye. The dye in this invention means a colorant that is soluble in at least one solvent at 23°C, and includes at least those commercially available as the Solvent series. In this embodiment, the colorant preferably includes Solvent Yellow and / or Solvent Red.

[0036] The colorant used in this embodiment preferably contains at least one of a red colorant and a yellow colorant in addition to tungsten oxide, which allows the colorant to exhibit a blackish color.

[0037] At least one of the colorants used in this embodiment is a dye. Specifically, the dye is preferably a red dye and / or a yellow dye, and more preferably contains both a red dye and a yellow dye.

[0038] The content of the red colorant (preferably a red dye) in the infrared absorbing layer of this embodiment is preferably 0.5% by mass or more, more preferably 1% by mass or more, and preferably 6% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and preferably 2% by mass or less. By setting the content to be equal to or greater than the lower limit, coloration of the projected image can be more effectively suppressed. Furthermore, by setting the content to be equal to or less than the upper limit, excellent transparency can be maintained. The content of the yellow colorant (preferably a yellow dye) in the infrared absorbing layer of this embodiment is preferably 0.5% by mass or more, more preferably 1% by mass or more, and preferably 6% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. By setting the content to be equal to or greater than the lower limit, coloration of the projected image can be more effectively suppressed. Furthermore, by setting the content to be equal to or less than the upper limit, excellent transparency can be maintained. The amounts of the red colorant and the yellow colorant to be blended and the ratio between them are preferably adjusted so that the infrared absorbing layer satisfies the desired light transmittance at a wavelength of 1000 nm and the ratio T / T1 of the total light transmittance T to the transmittance T1 at a wavelength of 1000 nm.

[0039] The content of the colorant other than tungsten oxide in the infrared absorbing layer of this embodiment is preferably 0.5% by mass or more, more preferably 1% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less. By making the content equal to or greater than the lower limit, coloration of the projected image can be more effectively suppressed. Furthermore, by making the content equal to or less than the upper limit, excellent transparency can be maintained. The infrared absorbing layer of this embodiment may contain only one type of dye, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0040] The infrared absorbing layer of this embodiment may contain a pigment other than tungsten oxide. Specific examples include red pigments and / or yellow pigments. In this embodiment, when the infrared absorbing layer contains a pigment other than tungsten oxide, it preferably contains a combination of a red pigment and a yellow dye, and / or a combination of a yellow pigment and a red dye. When pigments other than tungsten oxide are contained in the infrared absorbing layer of this embodiment, the total content of the pigments other than tungsten oxide in the infrared absorbing layer is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, and preferably 7% by mass or less, and more preferably 5% by mass or less. By setting the content at or above the lower limit, coloration of the projected image can be more effectively suppressed. Furthermore, by setting the content at or below the upper limit, excellent transparency can be maintained.

[0041] The infrared absorbing layer in this embodiment also preferably contains substantially no pigments other than tungsten oxide. Substantially no pigments other than tungsten oxide means that the content of pigments other than tungsten oxide contained in the infrared absorbing layer is preferably less than 10% by mass, more preferably less than 5% by mass, and even more preferably less than 1% by mass of the content of tungsten oxide.

[0042] <<Photopolymerization Initiator>> The photopolymerization initiator used in this embodiment may be any known photopolymerization initiator, as long as it cures the UV-curable resin. The photopolymerization initiator is preferably a photoradical generator that is cleaved by visible light or UV light having a wavelength shorter than 450 nm to generate radicals. Examples of the photopolymerization initiator include photopolymerization initiators having an acylphosphine oxide skeleton, an α-hydroxyketone skeleton, a benzyl dimethyl ketal skeleton, an aminoketone skeleton, a benzophenone skeleton, or a trichloromethyl group-containing triazine skeleton. Photopolymerization initiators having an acylphosphine oxide skeleton and / or an α-hydroxyketone skeleton are preferred. Specific examples of photopolymerization initiators include benzophenone, thioxanthone, benzyl dimethyl ketal, α-hydroxyketone, α-hydroxyalkylphenone, α-aminoketone, α-aminoalkylphenone, monoacylphosphine oxide, bisacylphosphine oxide, hydroxybenzophenone, aminobenzophenone, titanocene, oxime ester, and oxyphenylacetic acid ester. In addition to the above, as the polymerization initiator, the description in paragraph 0039 of WO 2023 / 095664, the description in paragraphs 0234 to 0238 of WO 2022 / 102736, the description in paragraphs 0135 and thereafter of JP-A-2010-106268, the description in paragraphs 0018 to 0025 of JP-A-2009-13115, and the description in paragraphs 0018 to 0025 of JP-A-2005-154312 can be taken into consideration, and the contents of these can be incorporated into this specification.

[0043] The content of the photopolymerization initiator contained in the infrared absorbing layer of this embodiment is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 1.2% by mass or more, and preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 4% by mass or less. By setting the content to be equal to or greater than the lower limit, sufficient curability can be exhibited. Furthermore, by setting the content to be equal to or less than the upper limit, storage stability and deterioration over time tend to be further improved. The infrared absorbing layer of this embodiment may contain only one type of photopolymerization initiator, or may contain two or more types. When two or more types are contained, it is preferable that the total amount be within the above range.

[0044] The infrared absorbing layer of this embodiment may contain a heat stabilizer. The content of the heat stabilizer in the infrared absorbing layer is preferably 0.1 to 20.0 mass %, more preferably 2 to 10.0 mass %. Only one type of heat stabilizer may be contained, or two or more types may be contained. When two or more types are contained, the total amount is preferably within the above range. By ensuring that the content is equal to or greater than the above lower limit, deterioration of the infrared absorbing layer during a heat and humidity test can be prevented.

[0045] <<Other Components>> In addition to the above components, the infrared absorbing layer may contain a leveling agent, an ultraviolet absorber, a light stabilizer, a flame retardant, a flame retardant aid, a colorant, an antistatic agent, a fluorescent brightener, an antifogging agent, a flowability improver, a plasticizer, a dispersant, an antibacterial agent, an antiblocking agent, an impact improver, a sliding improver, a hue improver, an acid trapping agent, etc. One of these components may be used alone, or two or more may be used in combination. The total amount of these other components in the infrared absorbing layer is preferably 0% by mass or more and less than 10% by mass, more preferably 0% by mass or more and less than 5% by mass, and may be 0% by mass or more and less than 1% by mass.

[0046] <<Light Stabilizer>> Examples of light stabilizers that can be used include hindered amine light stabilizers such as bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate, bis(1-undecanoxy-2,2,6,6-tetramethylpiperidin-4-yl)carbonate, 1,2,2,6,6-13-pentamethyl-4-piperidyl methacrylate, 2,2,6,6-tetramethyl-4-piperidyl methacrylate, bis[2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl]decanedioate, and bis[1,2,2,6,6-pentamethyl-4-piperidinyl]2-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]-2-butylpropanedioate. The content of the light stabilizer in the infrared absorbing layer is preferably 0 to 5% by mass, more preferably 0 to 3% by mass, and even more preferably 0 to 1% by mass. By setting the content to the upper limit or less, the ultraviolet curable resin tends to be cured more effectively.

[0047] Examples of flame retardants include halogen-based flame retardants and phosphorus-based flame retardants. Phosphorus-based flame retardants include aromatic phosphate ester compounds, phosphaphenanthrene compounds, metal phosphinates, ammonium polyphosphate, melamine polyphosphate, phosphate ester amides, and red phosphorus. For flame retardants, see paragraphs 0054 to 0082 of JP 2022-104214 A and paragraphs 0052 to 0077 of Japanese Patent No. 7021724, the contents of which are incorporated herein by reference.

[0048] In the infrared absorbing layer, the total of the ultraviolet curable resin, the photopolymerization initiator, and the colorant preferably accounts for 90% by mass or more, more preferably 95% by mass or more, and even more preferably 97% by mass or more of the infrared absorbing layer. Furthermore, in the infrared absorbing layer, the total of the ultraviolet curable resin, the photopolymerization initiator, and the colorant does not exceed 100% by mass.

[0049] The thickness of the infrared absorbing layer is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 1.5 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 5 μm or less. By setting the thickness at or below the upper limit, curing defects do not occur when curing with UV. Furthermore, by setting the thickness at or above the lower limit, the infrared absorbing layer exhibits greater effectiveness.

[0050] <Layer Structure of Multilayer Body> Next, the layer structure of the multilayer body of this embodiment will be described. The multilayer body of this embodiment has a base layer and an infrared absorbing layer. The base layer preferably includes an acrylic resin layer and a polycarbonate resin layer, and more preferably includes an acrylic resin layer and a polycarbonate resin layer, with the infrared absorbing layer being located on the side of the polycarbonate resin layer opposite the acrylic resin layer. This structure results in a multilayer body with even better weather resistance. Below, a preferred example of the multilayer body of this embodiment will be described with reference to FIG. 1. It goes without saying that the multilayer body of this embodiment is not limited to the one shown in FIG. 1. FIG. 1 is a cross-sectional schematic diagram showing an example of the multilayer body of this embodiment, in which 1 indicates the multilayer body, 2 indicates the acrylic resin layer, 3 indicates the polycarbonate resin layer, and 4 indicates the infrared absorbing layer. In the multilayer body 1 of this embodiment, it is preferred that the infrared absorbing layer 4 be located on the side of the polycarbonate resin layer 3 opposite the acrylic resin layer 2. This structure can improve the weather resistance of the multilayer body. In this specification, the acrylic resin layer 2 and the polycarbonate resin layer 3 may be collectively referred to as the substrate. It goes without saying that the substrate may include other layers within the scope of the present invention. Details of the other layers will be described later.

[0051] The infrared absorbing layer 4 may be the outermost layer of the multilayer body 1. Providing the infrared absorbing layer 4 tends to further improve the surface hardness of the multilayer body 1. In the multilayer body 1 of this embodiment, the acrylic resin layer 2, the polycarbonate resin layer 3, and the infrared absorbing layer 4 are laminated in this order, and the infrared absorbing layer 4 is preferably located on the surface of the polycarbonate resin layer 3. By being located on the surface of the polycarbonate resin layer 3, the formability of the infrared absorbing layer 2 (applicability of the infrared absorbing layer-forming composition) can be further improved. The multilayer body of this embodiment may include other layers as long as the acrylic resin layer 2, the polycarbonate resin layer 3, and the infrared absorbing layer 4 are laminated in the above order without departing from the spirit of this embodiment. However, it is preferable that the multilayer body does not include other layers, i.e., that the layers are adjacent to each other. Furthermore, the multilayer body of this embodiment may be a flame-retardant substrate in which the content of the metal sulfonate in at least one of the acrylic resin layer and the polycarbonate resin layer is 0.01 to 0.80% by mass. The use of such a flame-retardant substrate makes it suitable for applications requiring flame retardancy. These will be explained in more detail below.

[0052] The thickness (total thickness) of the multilayer body is not particularly limited, but is preferably 30 μm or more, more preferably 100 μm or more, and is preferably 10,000 μm or less, more preferably 5,000 μm or less, and even more preferably 2,000 μm or less, and may be 1,000 μm or less, or 500 μm or less.

[0053] The multilayer body of this embodiment preferably has excellent infrared shielding properties. Specifically, the light transmittance of the multilayer body of this embodiment at a wavelength of 1000 nm is preferably 60% or less, more preferably 40% or less, even more preferably 20% or less, and even more preferably 15% or less. The lower limit is not particularly specified, but a value of more than 0% is practical.

[0054] The multilayer body of this embodiment also preferably has excellent transparency. Specifically, the haze of the multilayer body measured in accordance with JIS K7136 is preferably 3% or less, more preferably 2% or less, even more preferably 1.5% or less, and even more preferably 1% or less. The lower limit is preferably 0% or more, but more preferably more than 0% is practical.

[0055] In the multilayer body of this embodiment, when the total light transmittance T of the multilayer body is 81% or more, the ratio T / T1 of the transmittance T1 at a wavelength of 1000 nm is preferably 1.5 or more, and is also preferably 20 or less, more preferably 4 or less, even more preferably 3.5 or less, still more preferably 3 or less, even more preferably 2 or less, and preferably 1.5 or more. Furthermore, in the multilayer body of this embodiment, when the total light transmittance T of the multilayer body is less than 81%, the ratio T / T1 of T1 is preferably 2 or more, preferably 30 or less, and more preferably 25 or less. By adopting such a configuration, the performance required for a head-up display can be satisfied.

[0056] The multilayer body of this embodiment is L ＊ a ＊ b ＊ In the color system, a ＊ value and b ＊ It is preferable that the value is close to 0. Specifically, ＊ a ＊ b ＊ In the color system, a ＊ value and b ＊ The absolute values ​​of the values ​​are each independently preferably 2.0 or less, more preferably 1.9 or less, even more preferably 1.8 or less, still more preferably 1.6 or less, even more preferably 1.0 or less, and preferably 0, and even if they are 0.001 or more, the required performance is sufficiently satisfied.

[0057] The multilayer body of this embodiment may also have flame retardancy. Specifically, the multilayer body preferably satisfies a C rating (burns up to the B standard line but the burning rate is 102 mm / min or less) in a combustion test (FMVSS test) based on FMVSS No. 302, and more preferably satisfies a B rating (burns within 51 mm (and within 60 seconds) from the A standard line and self-extinguishes) in the FMVSS test. ＊ value and b ＊ The values ​​and FMVSS test are measured as described in the Examples below.

[0058] The multilayer body of this embodiment preferably further includes a hard coat layer. The hard coat layer is preferably provided on at least one surface of the multilayer body, and more preferably on the side of the acrylic resin layer of the multilayer body opposite the polycarbonate resin layer. The hard coat layer may be the outermost layer of the multilayer body. By providing a hard coat layer, the surface hardness of the multilayer body tends to be further improved. In the multilayer body of this embodiment, the hard coat layer is preferably formed by laminating an infrared absorbing layer, a polycarbonate resin layer, an acrylic resin layer, and a hard coat layer in this order. In the multilayer body of this embodiment, the hard coat layer is preferably provided on the surface of the acrylic resin layer. By providing a hard coat layer on the surface of the acrylic resin layer, the coatability of the hard coat layer can be further improved.

[0059] The hard coat layer that may be included in the multilayer body of this embodiment is a layer having a higher surface hardness than the polycarbonate resin layer. By including such a hard coat layer, the surface hardness of the multilayer body or molded article can be increased. The thickness of the hard coat layer is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 2 μm or more, even more preferably 2.5 μm or more, and even more preferably 3 μm or more. By making the thickness equal to or greater than the lower limit, the pencil hardness of the entire multilayer body due to the hard coat layer tends to be further improved. The upper limit of the thickness of the hard coat layer is preferably 20 μm or less, more preferably 15 μm or less, even more preferably 12 μm or less, even more preferably 10 μm or less, even more preferably 8 μm or less, and may even be 5 μm or less. By making the thickness equal to or less than the upper limit, the flame retardancy tends to be further improved.

[0060] The hard coat layer is preferably obtained by applying and curing a hard coat material that can be cured by heat or active energy rays. Examples of coating materials that can be cured using active energy rays include resin compositions composed of a single or multiple monofunctional or polyfunctional (preferably di- to decafunctional) (meth)acrylate monomers or oligomers, and preferred examples include resin compositions containing monofunctional or polyfunctional (preferably di- to decafunctional) urethane (meth)acrylate oligomers. These resin compositions preferably contain a photopolymerization initiator as a curing catalyst. Examples of thermosetting resin coating materials include polyorganosiloxane-based and crosslinked acrylic-based coatings. Such resin compositions are commercially available as hard coat agents for acrylic or polycarbonate resin films or sheets, and can be selected appropriately taking into account suitability for the coating line. For the hard coat layer, the descriptions in paragraphs 0045 to 0055 of JP-A-2013-020130, the descriptions in paragraphs 0073 to 0076 of JP-A-2018-103518, and the descriptions in paragraphs 0062 to 0082 of JP-A-2017-213771 can be referred to, and the contents of these can be incorporated into this specification.

[0061] In addition to the above components, the hard coat layer preferably contains inorganic particles, organic pigments, ultraviolet absorbers, light stabilizers, heat stabilizers, flame retardants, flame retardant assistants, colorants, antistatic agents, fluorescent brighteners, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact improvers, sliding improvers, hue improvers, acid trapping agents, etc., and more preferably contains inorganic particles. These components may be used alone or in combination of two or more.

[0062] Examples of inorganic particles include nanoparticles made of metal or metal compound.For example, gold, silver, copper, platinum, palladium, nickel, cobalt, iron, manganese, silicon, titanium, zirconium, tungsten, molybdenum, chromium, zinc, aluminum, and composite metals made of two or more of these.In addition, examples of metal compounds include iron oxide, silicon oxide, zirconium oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, cobalt oxide, nickel oxide, cerium oxide, cupric oxide, zinc oxide, tin oxide, antimony oxide, titanium dioxide, aluminum oxide, indium tin oxide (ITO), cesium tungsten oxide (CWO) and their mixtures, metal oxides, metal carbides, metal borides, metal carbonates, zeolites, clay, and their composites, and silicon oxide is more preferred.

[0063] The inorganic particles may be surface-treated or may not be surface-treated. Preferably, the inorganic particles are surface-treated. The surface treatment agent is preferably a silane coupling agent.

[0064] The average particle size (D50) of the inorganic particles is preferably 5 nm or more, more preferably 7 nm or more, and preferably 30 nm or less, more preferably 20 nm or less. By setting the average particle size at or above the lower limit, the flame retardancy of the resulting multilayer body tends to be further improved. Furthermore, the smaller the average particle size, the larger the surface area relative to the blend mass, making it possible to form more crosslinked structures with other components.

[0065] The content of inorganic particles in the hard coat layer of this embodiment is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, and preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 35 parts by mass or less, per 100 parts by mass of the hard coat layer. By setting the content at or above the lower limit, the flame retardancy of the multilayer body tends to be further improved. Furthermore, by setting the content at or below the upper limit, the occurrence of cracks during a heat resistance test of the multilayer body tends to be more effectively suppressed. The hard coat layer may contain only one type of inorganic particles, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0066] Examples of flame retardants include halogen-based flame retardants and phosphorus-based flame retardants. Phosphorus-based flame retardants include aromatic phosphate ester compounds, phosphaphenanthrene compounds, metal phosphinates, ammonium polyphosphate, melamine polyphosphate, phosphate ester amides, and red phosphorus. For flame retardants, see paragraphs 0054 to 0082 of JP 2022-104214 A and paragraphs 0052 to 0077 of Japanese Patent No. 7021724, the contents of which are incorporated herein by reference.

[0067] The multilayer body of this embodiment may have other layers in addition to the above. Specific examples include an adhesive layer, a pressure-sensitive adhesive layer, an antifouling layer, an antireflection layer, a polarizing layer, and the like, with an antireflection layer being preferred. The antireflection layer is typically preferably provided on the underside of the infrared absorbing layer, opposite the polycarbonate resin layer (e.g., in FIG. 1), 4, but may also be provided on the polycarbonate side. For details of the antireflection layer, please refer to paragraphs 0062 to 0083 of JP-A No. 2023-114940, paragraphs 0013 to 0041 of JP-A No. 2022-174051, and paragraphs 0043 to 0046 of JP-A No. 2021-081596, the contents of which are incorporated herein by reference. The polarizing layer is typically preferably provided on the underside of the infrared absorbing layer, opposite the polycarbonate resin layer (e.g., in FIG. 1), 4. For details of the polarizing layer, please refer to the descriptions in paragraphs 0022 to 0029 of JP-A-2008-105225, the descriptions in paragraphs 0011 to 0021 of JP-A-2020-52406, and the descriptions in paragraphs 0014 to 0037 of JP-A-2023-13533, the contents of which are incorporated herein by reference.

[0068] The multilayer body may be subjected to one or more of the following treatments on at least one surface: anti-fingerprint treatment, anti-glare treatment, weather resistance treatment, antistatic treatment, anti-fouling treatment, and anti-blocking treatment. The anti-blocking treatment refers to a treatment that enables films to be easily peeled even when they are in close contact with each other, and examples of such treatment include adding an anti-blocking agent and providing unevenness on the surface of the multilayer body.

[0069] <<Polycarbonate Resin Layer>> The polycarbonate resin layer in this embodiment contains a polycarbonate resin. The polycarbonate resin is not particularly limited as long as it contains an —[O—R—OCO]— structural unit (R is a hydrocarbon group (for example, an aliphatic group, an aromatic group, or one containing both an aliphatic group and an aromatic group, and further one having a linear structure or a branched structure)) that contains a carbonate ester bond in the molecular main chain, and various polycarbonate resins can be used, with aromatic polycarbonate resins being preferred.

[0070] In this embodiment, the polycarbonate resin preferably contains a bisphenol-type polycarbonate resin. A bisphenol-type polycarbonate resin refers to a polycarbonate resin in which 80 mol% or more, preferably 90 mol% or more, and more preferably 95 mol% or more of the structural units constituting the polycarbonate resin are carbonate structural units derived from bisphenol and / or a derivative thereof. The bisphenol and / or a derivative thereof is preferably bisphenol A, bisphenol AP, bisphenol C, bisphenol BP, or a derivative thereof, more preferably bisphenol A, bisphenol AP, or a derivative thereof, and even more preferably bisphenol A or a derivative thereof. The bisphenol-type polycarbonate resin is preferably a bisphenol A-type polycarbonate resin.

[0071] The molecular weight of the polycarbonate resin is not particularly limited, but is preferably 20,000 or more, more preferably 22,000 or more, in terms of viscosity average molecular weight calculated from the solution viscosity measured at 25°C using methylene chloride as a solvent. The viscosity average molecular weight is preferably 35,000 or less, more preferably 32,000 or less, and even more preferably 30,000 or less. By setting the viscosity average molecular weight to the lower limit or more, the strength of the resulting flat-plate molded article can be increased. Setting the viscosity average molecular weight to the upper limit or less tends to improve moldability. Here, the viscosity average molecular weight [Mv] is calculated by using methylene chloride as a solvent and an Ubbelohde viscometer to determine the intrinsic viscosity [η] (unit: dL / g) at 25°C, and then calculating the viscosity average molecular weight using Schnell's viscosity formula, i.e., η = 1.23 × 10 －４ Mv ０．８３ The intrinsic viscosity [η] is the specific viscosity [η] at each solution concentration [C] (g / dL). ｓｐ ] was measured and the value was calculated according to the following formula. In this embodiment, two or more polycarbonate resins having different viscosity average molecular weights may be mixed and used, and in this case, the viscosity average molecular weight is the viscosity average molecular weight of the mixture.

[0072] The onset glass transition temperature (Tg) of the polycarbonate resin used in this embodiment is preferably 160 ° C. or lower, more preferably 155 ° C. or lower, even more preferably 154 ° C. or lower, even more preferably 153 ° C. or lower, even more preferably 152 ° C. or lower, and even more preferably 151 ° C. or lower. The onset glass transition temperature (Tg) of the polycarbonate resin used in this embodiment is, for example, 140 ° C. or higher, or even 143 ° C. or higher, 145 ° C. or higher, 147 ° C. or higher, or 148 ° C. or higher. The glass transition temperature is measured according to the description in paragraph 0056 of JP 2022-080270 A.

[0073] For details of the polycarbonate resin, the descriptions in paragraphs 0011 to 0020 of JP-A-2012-144604 and the descriptions in paragraphs 0014 to 0035 of JP-A-2019-002023 can be referred to as long as they do not deviate from the spirit of this embodiment, and the contents of these can be incorporated into this specification.

[0074] In this embodiment, the content of the polycarbonate resin in the polycarbonate resin layer is preferably 90% by mass or more, more preferably 92% by mass or more, even more preferably 94% by mass or more, even more preferably 96% by mass or more, still more preferably 97% by mass or more, and may be 98% by mass or more, based on 100% by mass of the polycarbonate resin layer. The upper limit may be 100% by mass. When the polycarbonate resin layer in this embodiment contains two or more types of polycarbonate resins, the total amount is preferably within the above range.

[0075] The polycarbonate resin layer in this embodiment may contain a metal sulfonate, which is a component generally used as a flame retardant for polycarbonate resins.

[0076] The metal sulfonate is preferably an alkali metal salt. The alkali metal constituting the alkali metal salt is preferably lithium, sodium, potassium, or rubidium, and more preferably sodium or potassium. The metal sulfonate may also contain a fluorine atom. The molecular weight of the metal sulfonate used in this embodiment is preferably 100 to 900, and more preferably 100 to 500.

[0077] Specific examples of the metal sulfonate salt used in this embodiment are shown below. It goes without saying that the metal sulfonate salt used in this embodiment is not limited to these.

[0078] The content of the sulfonate metal salt in the polycarbonate resin layer is preferably 0.01 to 0.80% by mass, more preferably 0.7% by mass or less, even more preferably 0.6% by mass or less, even more preferably 0.5% by mass or less, and even more preferably 0.4% by mass or less, and may be less than 0.1% by mass or 0.05% by mass or less depending on the application, etc. The polycarbonate resin layer in this embodiment may contain only one type of sulfonate metal salt, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0079] The polycarbonate resin layer in this embodiment may contain a flame retardant other than a metal sulfonate, for example, a phosphorus-based flame retardant such as a condensed phosphate ester or a phosphazene, a silicone-based flame retardant such as a polyorganosiloxane, or a halogen-based flame retardant such as a brominated polycarbonate oligomer. Specific examples of phosphorus-based flame retardants include condensed phosphate esters such as resorcinol bis-diphenyl phosphate (RDP), resorcinol bis-dixylenyl phosphate (RDX), bisphenol A bis-diphenyl phosphate (BDP), and biphenyl bis-diphenyl phosphate, as well as linear phenoxyphosphazenes and cyclic phenoxyphosphazenes. The content of the flame retardant in the polycarbonate resin layer is preferably 0.3 to 20% by mass, and more preferably 0.5 to 10% by mass.

[0080] The polycarbonate resin layer in this embodiment may contain an ultraviolet absorber such as a triazine-based ultraviolet absorber or a benzotriazole-based ultraviolet absorber. The content of the ultraviolet absorber in the polycarbonate resin layer is preferably 0.1 to 5.0% by mass, and more preferably 0.5 to 2.0% by mass.

[0081] In addition to the above components, the polycarbonate resin layer in this embodiment may contain antioxidants, release agents, flame retardant aids, heat stabilizers, colorants, antistatic agents, fluorescent brighteners, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact improvers, sliding improvers, hue improvers, acid trapping agents, etc. These components may be used alone or in combination of two or more. The total content of the above components is preferably 0 to 5% by mass of the polycarbonate resin layer, more preferably 0 to 3% by mass, even more preferably 0 to 1% by mass, even more preferably 0 to 0.5% by mass, even more preferably 0 to 0.3% by mass, and even more preferably 0 to 0.1% by mass.

[0082] Examples of antioxidants include phenol-based antioxidants, amine-based antioxidants, phosphorus-based antioxidants, thioether-based antioxidants, etc. Among these, in the present embodiment, phosphorus-based antioxidants and phenol-based antioxidants (more preferably hindered phenol-based antioxidants) are preferred, and phosphorus-based antioxidants are more preferred.

[0083] The phosphorus-based antioxidant is preferably a phosphite-based antioxidant, and a phosphite compound represented by the following formula (1) or (2) is preferred. (In formula (1), R １１ and R １２ each independently represents an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms. (In formula (2), R １３ ~R １７ each independently represents a hydrogen atom, an aryl group having 6 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms.

[0084] In the above formula (1), R １１, R １２ Each of the alkyl groups represented by the formula (I) is preferably a linear or branched alkyl group having 1 to 10 carbon atoms. １１ , R １２ When is an aryl group, it is preferably an aryl group represented by any one of the following formulae (1-a), (1-b), and (1-c): * in the formula represents the bonding position.

[0085] (In formula (1-a), R Ａ each independently represents an alkyl group having 1 to 10 carbon atoms. Ｂ each independently represents an alkyl group having 1 to 10 carbon atoms.

[0086] For the hindered phenol-based antioxidant, reference can be made to the descriptions in paragraph 0063 of JP-A-2018-090677 and paragraph 0076 of JP-A-2018-188496, the contents of which are incorporated herein by reference.

[0087] In addition to the above, the antioxidants can be found in paragraphs 0057 to 0061 of JP 2017-031313 A, the contents of which are incorporated herein by reference.

[0088] The content of the antioxidant is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, even more preferably 0.010 parts by mass or more, and even more preferably 0.050 parts by mass or more, relative to 100 parts by mass of the polycarbonate resin layer. The upper limit of the antioxidant content is preferably 0.500 parts by mass or less, more preferably 0.300 parts by mass or less, even more preferably 0.200 parts by mass or less, even more preferably 0.150 parts by mass or less, even more preferably 0.100 parts by mass or less, and particularly preferably 0.080 parts by mass or less, relative to 100 parts by mass of the polycarbonate resin layer. One or more antioxidants may be used. When two or more antioxidants are used, the total amount is preferably within the above range.

[0089] Next, the release agent that can be contained in the polycarbonate resin layer will be described. The type of release agent is not particularly limited, but examples include aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds with a number average molecular weight of 200 to 15,000, polyethers with a number average molecular weight of 100 to 5,000, and polysiloxane-based silicone oils.

[0090] For details of the release agent, please refer to paragraphs 0035 to 0039 of WO 2015 / 190162, the contents of which are incorporated herein by reference.

[0091] The content of the release agent is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, even more preferably 0.010 parts by mass or more, and even more preferably 0.050 parts by mass or more, relative to 100 parts by mass of the polycarbonate resin layer. The upper limit is preferably 0.5 parts by mass or less, more preferably 0.3 parts by mass or less, and even more preferably 0.1 parts by mass or less. Only one type of release agent may be used, or two or more types may be used. When two or more types are used, it is preferable that the total amount be within the above range.

[0092] The thickness of the polycarbonate resin layer is preferably 50 μm or more, more preferably 100 μm or more, and even more preferably 150 μm or more. By making the thickness equal to or greater than the lower limit, molding becomes easier and flame retardancy tends to be improved. Furthermore, the upper limit of the thickness of the polycarbonate resin layer is preferably 1000 μm or less, more preferably 750 μm or less, and even more preferably 500 μm or less.

[0093] <<Acrylic Resin Layer>> The acrylic resin layer in this embodiment contains an acrylic resin. The acrylic resin layer may be a single layer or may be a multilayer, but is preferably a single layer.

[0094] As described above, the acrylic resin layer in this embodiment contains an acrylic resin. An example of the acrylic resin is preferably a polymer containing alkyl (meth)acrylate units (preferably alkyl methacrylate units) in an amount of 50% by mass or more (preferably 90% by mass or more) of all structural units, and more preferably a polymer containing methyl (meth)acrylate units (preferably methyl methacrylate units) in an amount of 50% by mass or more (preferably 90% by mass or more) of all structural units. Examples of structural units other than alkyl (meth)acrylate units include other (meth)acrylate units, styrene units, cyclic acid anhydride units, N-substituted maleimide units, and lactone ring units.

[0095] The acrylic resin layer may be made of only an acrylic resin, or may contain, in addition to the acrylic resin, other thermoplastic resins, preferably at least one thermoplastic resin selected from a styrene-based resin, a fluorine-based resin such as polyvinylidene fluoride, and an aromatic polyether resin such as polyphenylene ether, and more preferably a styrene-based resin.

[0096] An example of the acrylic resin layer is a layer composed of 90% by mass or more (preferably 95% by mass or more, more preferably 97% by mass or more, and even more preferably 98% by mass or more) of an acrylic resin. Another example of the acrylic resin is a layer composed of 90% by mass or more (preferably 95% by mass or more, more preferably 97% by mass or more, and even more preferably 98% by mass or more) of the acrylic resin and another thermoplastic resin (preferably a styrene-based resin).

[0097] The weight-average molecular weight of the acrylic resin is not particularly limited, but is preferably 10,000 or more, more preferably 30,000 or more, even more preferably 50,000 or more, still more preferably 60,000 or more, and even more preferably 70,000 or more. The weight-average molecular weight of the acrylic resin is preferably 250,000 or less, more preferably 200,000 or less, even more preferably 150,000 or less, still more preferably 100,000 or less, and even more preferably 90,000 or less.

[0098] The glass transition temperature of the acrylic resin layer used in this embodiment is preferably 80°C or higher, more preferably 90°C or higher, even more preferably 95°C or higher, even more preferably 100°C or higher, and even more preferably 105°C or higher. The upper limit is not particularly specified, but, for example, 200°C or lower is practical. The glass transition temperature is measured according to the description in paragraph 0056 of JP 2022-080270 A.

[0099] In addition to the above components, the acrylic resin layer may contain inorganic particles, antioxidants, release agents, UV absorbers, heat stabilizers, flame retardants, flame retardant aids, colorants, antistatic agents, fluorescent brighteners, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact improvers, sliding improvers, hue improvers, acid trapping agents, etc. These components may be used alone or in combination of two or more. The total content of the above components is preferably 0 to 5% by mass of the acrylic resin layer, more preferably 0 to 3% by mass, even more preferably 0 to 1% by mass, even more preferably 0 to 0.5% by mass, even more preferably 0 to 0.3% by mass, and even more preferably 0 to 0.1% by mass.

[0100] As described above, the acrylic resin layer in this embodiment may contain a flame retardant. Examples of the flame retardant that may be contained in the acrylic resin layer include phosphorus-based flame retardants and metal sulfonates, and phosphorus-based flame retardants are preferred.

[0101] Examples of phosphorus-based flame retardants include aromatic phosphate ester compounds, phosphazene compounds, phosphaphenanthrene compounds, metal phosphinates, ammonium polyphosphate, melamine polyphosphate, phosphate ester amides, and red phosphorus, with aromatic phosphate ester compounds, phosphazene compounds, and phosphaphenanthrene compounds being preferred.

[0102] Examples of aromatic phosphate ester compounds include resorcinol diphenyl phosphate, hydroquinone diphenyl phosphate, bisphenol A diphenyl phosphate, biphenyl diphenyl phosphate, etc. Commercially available products thereof include PX-202, CR-741, PX-200, and PX-201 manufactured by Daihachi Chemical Industry Co., Ltd., and FP-500, FP-600, FP-700, and PFR manufactured by ADEKA Corporation.

[0103] Examples of aromatic phosphate ester compounds include cyclic phenoxyphosphazene and its derivatives, etc. Commercially available products include Lavitol FP-110 manufactured by Fushimi Pharmaceutical Co., Ltd.

[0104] Phosphaphenanthrene compounds are phosphorus-based flame retardants having at least one phosphaphenanthrene skeleton in the molecule, and commercially available products include HCA, HCA-HQ, BCA, SANKO-220, and M-Ester manufactured by Sankosha.

[0105] The metal phosphinate salt is a phosphinate salt and / or a diphosphinate salt and / or a polymer thereof. Examples of the salt include calcium, aluminum, and zinc salts. Commercially available metal phosphinate salts include "Exolit" (registered trademark) OP1230 and OP1240 manufactured by Clariant Japan.

[0106] Phosphate ester amide is an aromatic amide-based flame retardant containing a phosphorus atom and a nitrogen atom. A commercially available phosphorus ester amide product such as SP-703 manufactured by Shikoku Chemicals Co., Ltd. is preferably used.

[0107] Examples of ammonium polyphosphate include ammonium polyphosphate, melamine-modified ammonium polyphosphate, and carbamyl ammonium polyphosphate. Examples of the melamine polyphosphate include melamine phosphate, melamine pyrophosphate, and melamine polyphosphates such as melamine, melam, and melem phosphates. Products such as MPP-A manufactured by Sanwa Chemical Co., Ltd. and PMP-100 and PMP-200 manufactured by Nissan Chemical Industries, Ltd. are preferably used.

[0108] When the acrylic resin layer contains a flame retardant (phosphorus-based flame retardant, sulfonic acid metal salt, or other flame retardant), the content thereof is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 5 parts by mass or more, and even more preferably 7 parts by mass or more, per 100 parts by mass of the acrylic resin layer. The upper limit of the content of the flame retardant is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, per 100 parts by mass of the acrylic resin layer. The acrylic resin layer may contain only one type of flame retardant, or two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0109] The thickness of the acrylic resin layer is preferably 50 μm or more, more preferably 100 μm or more, and even more preferably 150 μm or more. By making the thickness equal to or greater than the lower limit, molding becomes easier and hardness tends to improve. Furthermore, the upper limit of the thickness of the acrylic resin layer is preferably 1000 μm or less, more preferably 750 μm or less, and even more preferably 500 μm or less.

[0110] <Method for producing multilayer body> The multilayer body of this embodiment can be produced by a known method. For example, the multilayer body of this embodiment can be produced by using a main extruder that extrudes a polycarbonate resin layer-forming composition and a sub-extruder that extrudes an acrylic resin layer-forming composition, melting the resins under the conditions of the resins used, introducing them into an extrusion die, laminating them inside the die and forming them into a sheet, or laminating them after forming them into a sheet, thereby forming a substrate. Furthermore, the multilayer body can be produced by applying a composition for forming an infrared-absorbing layer to the polycarbonate resin layer side of the substrate and curing it.

[0111] The multilayer body of this embodiment may be used as is, but can also be processed, particularly by heat processing, to form a molded article.

[0112] <Applications> The multilayer body of this embodiment can be suitably used for optical components, decorative products, anti-reflection molded articles, etc. The multilayer body of this embodiment can be suitably used for components such as display devices, electrical and electronic devices, office automation equipment, portable information terminals, machine parts, home appliances, vehicle parts, various containers, and lighting equipment. Among these, it is particularly suitable for use in housings for various displays, electrical and electronic devices, office automation equipment, portable information terminals, and home appliances, lighting equipment, and vehicle parts (particularly vehicle interior parts), surface films for smartphones and touch panels, etc., optical materials, and optical discs. In particular, the multilayer body of this embodiment can be preferably used as a dustproof cover for a head-up display.

[0113] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

[0114] 1. Raw Materials Urethane acrylate: UN-3320HC, solid content 100% by mass, weight average molecular weight 1,500, number of functional groups 6, manufactured by Negami Chemical Industrial Co., Ltd. Solvent Yellow 163: yellow dye, manufactured by Kiwa Chemical Industry Co., Ltd. Solvent Red 27: red dye, manufactured by Orient Chemical Industry Co., Ltd. Pigment Red 254-based pigment: red pigment, MIBK dispersion liquid used, solid content 20% by mass, manufactured by Nikko Bix Co., Ltd. FeOOH-based pigment: yellow pigment, PGM dispersion liquid used, solid content 20% by mass YMF-02A: CWO (cesium tungsten oxide) dispersion liquid, CWO content 18.5% by mass, manufactured by Sumitomo Metal Mining Co., Ltd.

[0115] Omnirad 819: acylphosphine oxide photopolymerization initiator, solid content 100% by mass, manufactured by IGM RESINS B.V. BYK-UV3575: silicone leveling agent, manufactured by BYK

[0116] PC / PMMA film: two-layer film of polycarbonate resin layer and acrylic resin layer, DF02U, manufactured by Mitsubishi Gas Chemical Company, thickness 0.375 mm

[0117] The composition of the flame-retardant base material is as follows: E-2000F: Polycarbonate resin obtained by interfacial polymerization using bisphenol A as a starting material (Mitsubishi Gas Chemical Company, Inc., E-2000F, viscosity average molecular weight: 27,000, Tg: 150°C) KSS-FR: Arichem, KSS-FR, potassium diphenylsulfone-3-sulfonate 2112: Tris(2,4-di-tert-butylphenyl)phosphite (phosphorus-based antioxidant, ADEKA, Adekastab 2112) S-100A: Glycerin monostearate (Rikemal S-100A, Riken Vitamin Co., Ltd.) 80HD: Asahi Kasei, polymethyl methacrylate

[0118] <Production of Flame-Retardant Substrate> A resin composition (pellet) for forming a polycarbonate resin layer (PC layer) and a resin composition (pellet) for forming an acrylic resin layer were produced according to the following method. Each of the components described above was weighed out to the amount shown in Table 1 (each component in Table 1 is expressed in mass%). After mixing for 15 minutes in a tumbler, the mixture was melt-kneaded in a vented twin-screw extruder with a screw diameter of 32 mm ("TEX30α" manufactured by The Japan Steel Works, Ltd.), and pellets were obtained by strand cutting. The resin composition (pellet) for forming the polycarbonate resin layer was melt-kneaded at 260 to 300°C, with the temperature being changed as needed depending on the resin viscosity, and the resin composition (pellet) for forming the acrylic resin layer was melt-kneaded at 260°C.

[0119] Flame-retardant substrates were molded using a multi-layer extrusion device having a single-screw extruder with a shaft diameter of 32 mm, a single-screw extruder with a shaft diameter of 65 mm, a feed block connected to all extruders, and a 650 mm wide T-die connected to the feed block. The resin composition (pellets) for the acrylic resin layer of each flame-retardant substrate shown in Table 1 was introduced into the single-screw extruder with a shaft diameter of 32 mm, and extruded under conditions of a cylinder temperature of 240 ° C and a discharge rate of 0.3 to 6.4 kg / h. Furthermore, the resin composition (pellets) for forming the polycarbonate resin layer of each flame-retardant substrate shown in Table 1 was continuously introduced into a single-screw extruder with a shaft diameter of 65 mm, and the cylinder temperature was changed from 250 ° C to 290 ° C depending on the resin viscosity, while the discharge rate was 17.4 to 23.5 kg / h. The feed block connected to all extruders was equipped with a two-type, two-layer distribution pin, and extruded and laminated. The extruded material was extruded into a sheet form through a T-die connected to the end of the die, and cooled while transferring a mirror surface using three mirror-finishing rolls set at temperatures of 120°C, 120°C, and 140°C from the upstream side, to obtain each flame-retardant substrate.

[0120] 2. Examples 1 to 13 and Comparative Examples 1 to 3 <Preparation of Multilayer Body (Coating of Infrared Absorbing Layer)> Component (A), component (B), component (C), and a leveling agent shown in Table 2 or Table 3 were mixed and stirred to obtain a composition for forming an infrared absorbing layer. In Tables 2 and 3, the proportion of each component indicates the solid content (parts by mass). The composition for forming an infrared absorbing layer obtained above was applied to the coated surface of the substrate shown in Table 2 using a bar coater. The applied composition for forming an infrared absorbing layer was dried in an oven at 80°C for 3 minutes, and then irradiated with an ultraviolet ray irradiator manufactured by Heraeus K.K. under a nitrogen atmosphere with an integrated light dose of 500 mJ / cm. ２ (UV illuminance meter manufactured by Oak Corporation, measurement wavelength 360 nm)

[0121] <Coating a Hard Coat Layer on the Opposite Side> A hard coat layer was formed on the surface opposite to the surface on which the infrared absorbing layer was formed of the multilayer body prepared above. In Table 2, a and b indicate the resin compositions used for the hard coat layer, and the following resin compositions were used. a: HO3313U-10 manufactured by Fujikura Chemical Industries, Ltd. b: UN-3320HC manufactured by Negami Chemical Industries, Ltd. A hard coat layer resin composition comprising 67.5 mass% of HO3313U-10, 29.0 mass% of silica particles surface-treated with 3-acryloxypropyltrimethoxysilane, 2.5 mass% of photoinitiator, and 1 mass% of leveling agent. The hard coat layer resin composition was applied with a bar coater to the outermost surface (surface of the acrylic resin layer) of the multilayer body opposite to the side on which the infrared absorbing layer was formed. The applied hard coat layer resin composition was dried in an oven at 80°C for 3 minutes, and then irradiated with an ultraviolet ray irradiator manufactured by Heraeus K.K. under a nitrogen atmosphere with an integrated light dose of 500 mJ / cm. ２ (UV illuminance meter manufactured by Oak Corporation, measurement wavelength 360 nm) to prepare a hard coat layer having a thickness of 4 μm.

[0122] <Total Light Transmittance> The total light transmittance of the multilayer body was measured based on JIS K 7375:2008 using "HM-150" manufactured by Murakami Color Co., Ltd.

[0123] <Transmittance at a wavelength of 1000 nm> The transmittance of light at a wavelength of 1000 nm of the multilayer body was measured using a spectrophotometer U-4000 manufactured by Hitachi High-Technologies Corporation.

[0124] <Ratio (T / T1)> The ratio T / T1 of the total light transmittance T of the multilayer body to the transmittance T1 at a wavelength of 1000 nm was calculated.

[0125] <Haze of Multilayer Body> The haze of the multilayer body was evaluated based on JIS K 7136: 2000. Haze was measured using "HM-150" manufactured by Murakami Color Co., Ltd.

[0126] <a ＊ value and b ＊ Value > a of multilayer body ＊ value and b ＊ The values ​​were evaluated in a transmission mode using a spectrophotometer / colorimeter "SD 7000" manufactured by Nippon Denshoku Industries Co., Ltd., under conditions of a D65 light source and a 2° viewing angle.

[0127] <Evaluation of Projected Image> A white image was projected using a projector through the multilayer body obtained above. The color of the projected image was evaluated as follows: A: No change in color was observed; B: Slight coloring was observed; C: Significant coloring was observed.

[0128] <FMVSS Test> Using an FMVSS No. 302 flammability tester, the multilayer body obtained above was measured for a burning distance of 254 mm between the gauge lines by applying a burner flame 38 mm from the right end of the test piece (350 mm x 100 mm x 0.375 mm) for 15 seconds. The test jig was used without a wire, and the burning rate was measured as follows: A: The test piece did not ignite or self-extinguished just before the A standard line; B: The burning distance was within 51 mm (and within 60 seconds) from the A standard line; C: The test piece burned up to the B standard line, but the burning rate was 102 mm / min or less; D: The test piece burned up to the B standard line, but the burning rate was faster than 102 mm / min.

[0129]

[0130]

[0131] In the table, the Pigment Red 254-based pigment and the FeOOH-based pigment each indicate the amount of solids. In the table, CWO indicates the amount of CWO (YMF-02A) in the CWO dispersion. In the table, PMMA-side HC indicates whether or not a hard coat layer was provided on the surface of the acrylic resin layer, and a and b indicate the composition of the resin composition for the hard coat layer. In the table, the ratio (T / T1) indicates the ratio T / T1 of the total light transmittance T of the multilayer body to the transmittance T1 at a wavelength of 1000 nm. As is clear from the results, the multilayer bodies of the present invention had low haze, no bluish tinge in the projected image, high total light transmittance, and low near-infrared transmittance (Examples 1 to 9). In contrast, when the infrared absorbing layer contained only a tungsten oxide pigment as a colorant (Comparative Example 1), the resulting multilayer body exhibited a significant change in color compared to a white image. In addition, when the infrared absorbing layer contains other pigments as colorants in addition to the tungsten oxide pigment (Comparative Example 2), the resulting multilayer body was able to suppress color changes relative to the white image, but the haze was high. Furthermore, when the infrared absorbing layer contains only a dye as a colorant (Comparative Example 3), the resulting multilayer body was observed to change color relative to the white image and was strongly bluish.

[0132] 1 Multilayer body 2 Acrylic resin layer 3 Polycarbonate resin layer 4 Infrared absorbing layer

Claims

1. A multilayer body having a base layer and an infrared absorbing layer, the infrared absorbing layer containing an ultraviolet curable resin, two or more types of colorants and a photopolymerization initiator, the colorant containing tungsten oxide and a dye.

2. L of the multilayer body ＊ a ＊ b ＊ In the color system, a ＊ value and b ＊ 2. The multilayer body of claim 1 , wherein the absolute value of each of the above values ​​is independently 2.0 or less.

3. A multilayer body according to claim 1 or 2, in which when the total light transmittance T of the multilayer body is 81% or more, the ratio T / T1 of the transmittance T1 at a wavelength of 1000 nm is 1.5 or more, and when the total light transmittance T is less than 81%, the ratio T / T1 of T1 is 2 or more.

4. The multilayer body according to any one of claims 1 to 3, wherein the base layer comprises an acrylic resin layer and a polycarbonate resin layer, and the infrared absorbing layer is located on the surface of the polycarbonate resin layer opposite to the acrylic resin layer.

5. The multilayer body according to claim 4, wherein the content of the metal sulfonate in at least one of the acrylic resin layer and the polycarbonate resin layer is 0.01 to 0.80% by mass.

6. The multilayer body according to claim 4, wherein the content of the metal salt of sulfonate in the polycarbonate resin layer is 0.01 to 0.80% by mass.

7. The multilayer body according to any one of claims 1 to 6, which has a haze of 2.0% or less as measured in accordance with JIS K7136.

8. The multilayer body according to any one of claims 1 to 7, wherein the infrared absorbing layer contains 20 mass % or more of the tungsten oxide.

9. The multilayer body according to any one of claims 1 to 8, wherein the infrared absorbing layer contains a red colorant and a yellow colorant in an amount of 0.5 to 6 mass % each.

10. The multilayer body according to any one of claims 1 to 9, wherein the infrared absorbing layer contains a red dye and a yellow dye in an amount of 0.5 to 6 mass % each.

11. The multilayer body according to any one of claims 1 to 10, further comprising a hard coat layer, the hard coat being formed by laminating an infrared absorbing layer, a polycarbonate resin layer, an acrylic resin layer and a hard coat layer in this order.

12. The multilayer body according to claim 11, wherein the hard coat layer contains inorganic particles.

13. The multilayer body according to any one of claims 1 to 12, further comprising an antireflection layer.

14. The multilayer body according to any one of claims 1 to 13, further comprising a polarizing layer.

15. A dustproof cover for a head-up display, comprising the multilayer body according to any one of claims 1 to 14.

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