Multilayer dust cover for head-up display

Abstract

Provided are a multilayer body having excellent weather resistance, adhesion, and transparency, and a dust cover for a head-up display using the multilayer body, the multilayer body having an acrylic resin layer, a polycarbonate resin layer, and an infrared ray absorbing layer, the infrared ray absorbing layer containing an ultraviolet curable resin, a photopolymerization initiator, and a colorant, the ultraviolet curable resin contains a component derived from a bifunctional (meth) acrylate monomer (A-1) having an alicyclic ring and / or an aromatic ring, the proportion of the component derived from the monomer (A-1) in the infrared absorption layer is 10-31 mass%, and the colorant includes a tungsten oxide. The infrared ray absorbing layer is located on the surface of the polycarbonate resin layer opposite to the acrylic resin layer.

Description

Technical Field

[0001] This invention relates to a multilayer dust cover for head-up displays. In particular, it relates to a multilayer comprising a polycarbonate resin layer and an acrylic resin layer. Background Technology

[0002] In addition to its excellent transparency, polycarbonate resin also has superior processability and impact resistance compared to glass. Furthermore, compared to other plastic materials, there is no need to worry about toxic gases. Therefore, it is widely used in various fields and is also used as a thermoforming material for vacuum forming and air compression forming.

[0003] On the other hand, because polycarbonate resin typically has low surface hardness, molded products made from polycarbonate resin are often easily scratched. Therefore, research has been conducted on techniques that, when polycarbonate resin is formed into a film, form a layer containing acrylic resin or an infrared absorbing layer (protective layer) on the surface to prevent scratches on the product surface. Such multilayers are described in Patent Documents 1 and 2.

[0004] Existing technical documents Patent documents Patent Document 1: International Publication No. 2016 / 060100 Patent Document 2: International Publication No. 2021 / 215435 Summary of the Invention

[0005] The problem that the invention aims to solve Therefore, by placing an infrared absorbing layer on one side of the polycarbonate resin layer in a multilayer comprising a polycarbonate resin layer and an acrylic resin layer containing acrylic resin, the infrared shielding performance can be improved. However, the adhesion (seamlessness) between the polycarbonate resin layer and the infrared absorbing layer becomes a problem. Moreover, such multilayers also need to be transparent.

[0006] The purpose of this invention is to solve related problems and to provide a multilayer body with excellent weather resistance, adhesion and transparency, as well as a dust cover for a head-up display using the multilayer body.

[0007] Technical solutions for solving the problem After conducting research on the above-mentioned issues, the inventors of this invention discovered that by employing a structure in which the infrared absorption layer is located on the side of the polycarbonate resin layer opposite to the acrylic resin layer in a multilayer having an acrylic resin layer, a polycarbonate resin layer, and an infrared absorption layer, and by incorporating a predetermined amount of (meth)acrylate monomer into the infrared absorption layer, the above-mentioned issues can be resolved.

[0008] Specifically, the above-mentioned problems were solved through the following solution.

[0009] <1> A multilayer comprising an acrylic resin layer, a polycarbonate resin layer, and an infrared absorbing layer. The aforementioned infrared absorbing layer comprises an ultraviolet-curable resin, a photopolymerization initiator, and a colorant. The aforementioned UV-curable resin contains a component derived from a bifunctional (meth)acrylate monomer (A-1) having an alicyclic and / or aromatic ring, and the proportion of the component derived from the aforementioned monomer (A-1) in the aforementioned infrared absorption layer is 10-31% by mass. The aforementioned colorants include tungsten oxide. The aforementioned infrared absorbing layer is located on the side of the polycarbonate resin layer opposite to the acrylic resin layer.

[0010] <2> according to <1> The multilayer body, wherein the monomer (A-1) includes the monomer represented by formula (1-1) and / or the monomer represented by formula (1-2). In equations (1-1) and (1-2), n and m are independent numbers that satisfy the condition that n+m is greater than 3 and less than 5.

[0011] <3> according to <1> or <2> The aforementioned multilayer body has a haze value of less than 2%.

[0012] <4> according to <1> ~ <3> In any one of the multilayer bodies, the proportion of the tungsten oxide in the infrared absorbing layer is 20% by mass or more.

[0013] <5> according to <1> ~ <4> The multilayer body according to any one of the above-mentioned photopolymerization initiators includes a photopolymerization initiator having an acylphosphine oxide backbone and / or an α-hydroxyketone backbone.

[0014] <6> according to <1> ~ <5> In any one of the multilayers, the sulfonate metal salt content of at least one of the acrylic resin layer and the polycarbonate resin layer is 0.01 to 0.80 by mass.

[0015] <7> according to <1> ~ <5> In any one of the multilayer bodies, the content of the sulfonate metal salt in the polycarbonate resin layer is 0.01 to 0.80 by mass.

[0016] <8> according to <1> ~ <7> The multilayer body according to any one of the following methods, wherein the multilayer body further comprises a hard coating layer, wherein the hard coating layer is stacked in the order of infrared absorbing layer, polycarbonate resin layer, acrylic resin layer and hard coating layer.

[0017] <9> according to <8> The multilayer body, wherein the hard coating contains inorganic particles.

[0018] <10> according to <1> ~ <9> The multilayer body according to any one of the following methods, wherein the multilayer body further comprises an anti-reflective layer.

[0019] <11> according to <1> ~ <10> The multilayer body according to any one of the following methods, wherein the multilayer body further comprises a polarizing layer.

[0020] <12> A dust cover for a head-up display, wherein the dust cover for a head-up display includes <1> ~ <11> The multilayer body as described in any one of the following.

[0021] Invention Effects According to the present invention, a multilayer body with excellent weather resistance, adhesion and transparency can be provided, as well as a dust cover for a head-up display using the multilayer body. Attached Figure Description

[0022] Figure 1 This is a cross-sectional schematic diagram illustrating an example of the multilayer body of the present invention. Detailed Implementation

[0023] The following will describe in detail specific embodiments for implementing the present invention (hereinafter referred to as "this embodiment"). It should be noted that the following embodiments are merely illustrative examples for illustrating the present invention, and the present invention is not limited to these embodiments.

[0024] It should be noted that in this specification, "~" is used to indicate the lower and upper limits, including the values ​​recorded before and after it.

[0025] Unless otherwise stated, all property values ​​and characteristic values ​​in this specification refer to values ​​at 23°C.

[0026] In this specification, unless otherwise stated, the weight-average molecular weight and number-average molecular weight are polystyrene equivalent values ​​determined by GPC (gel permeation chromatography).

[0027] In this specification, "(meth)acrylate" means either or both of acrylate and methacrylate.

[0028] In this specification, "multilayer body" means including articles that form the shape 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. Furthermore, "film" and "sheet" in this specification can be single-layered or multi-layered.

[0029] Where the measurement methods described in accordance with the standards given in this instruction manual vary from year to year, the standards based on the date of January 1, 2022 shall be used unless otherwise stated.

[0030] The accompanying diagrams are schematic diagrams, and the scale may differ from the actual figures.

[0031] In this specification, near-infrared light refers to light with a wavelength of 700nm to 2500nm.

[0032] The multilayer body of this embodiment is a multilayer body having an acrylic resin layer, a polycarbonate resin layer and an infrared absorption layer. The infrared absorption layer is characterized in that the infrared absorption layer comprises an ultraviolet-curable resin, a photopolymerization initiator and a colorant. The ultraviolet-curable resin contains a component derived from a bifunctional (meth)acrylate monomer (A) having an alicyclic and / or aromatic ring. The proportion of the component derived from the monomer (A) in the infrared absorption layer is 10 to 31% by mass. The colorant includes tungsten oxide. The infrared absorption layer is located on the side of the polycarbonate resin layer opposite to the acrylic resin layer.

[0033] This configuration provides a multilayer with excellent weather resistance, adhesion, and transparency.

[0034] In multilayers comprising an acrylic resin layer, a polycarbonate resin layer, and an infrared absorbing layer, weather resistance can be improved by employing a structure where the infrared absorbing layer is located on the side of the polycarbonate resin layer opposite to the acrylic resin layer. However, the adhesion between the polycarbonate resin layer and the infrared absorbing layer is often poor. Furthermore, it is known that transparency may be compromised when attempting to improve adhesion.

[0035] In this embodiment, the above-mentioned problems are successfully solved by including an infrared absorption layer comprising an ultraviolet-curable resin, a photopolymerization initiator, and a colorant, and by using a composition in which the ultraviolet-curable resin contains a component derived from a bifunctional (meth)acrylate monomer (A) having an alicyclic and / or aromatic ring, such that the proportion of the component derived from monomer (A) in the infrared absorption layer is 10 to 31% by mass, and the colorant comprises tungsten oxide.

[0036] That is, because monomers with alicyclic and / or aromatic rings have a large-volume backbone, the resulting resins readily interact with each other and stress relaxation is easily achieved. The inventors infer that, due to the ease of stress relaxation, it is possible to suppress peeling caused by stress applied in situations such as when coating an infrared absorbing layer onto a substrate having an acrylic resin layer and a polycarbonate resin layer.

[0037] Furthermore, monofunctional (meth)acrylate monomers often exhibit lower curing performance and poorer adhesion. On the other hand, trifunctional (meth)acrylate monomers are inferred to have high curing performance but are less likely to achieve stress relaxation. Therefore, the inventors deduced that, in comparison, by using difunctional (meth)acrylate monomers, a balance between curing performance and stress relaxation can be achieved with sufficient adhesion.

[0038] The following describes the details of the invention.

[0039] <Layer Composition of Multi-layer Structures> The layer structure of the multilayer body in this embodiment is referenced. Figure 1 This will be explained. It goes without saying that the multilayer structure in this embodiment is not limited to... Figure 1 The method described above.

[0040] Figure 1 This is a cross-sectional schematic diagram illustrating an example of a multilayer structure according to this embodiment. 1 represents the multilayer structure, 2 represents the acrylic resin layer, 3 represents the polycarbonate resin layer, and 4 represents the infrared absorbing layer. In the multilayer structure 1 of this embodiment, the infrared absorbing layer 4 is located on the side of the polycarbonate resin layer 3 opposite to the acrylic resin layer 2. This configuration improves the weather resistance of the multilayer structure. It should be noted that in this specification, the acrylic resin layer 2 and the polycarbonate resin layer 3 are sometimes referred to together as the substrate. Furthermore, it is self-evident that the substrate may also include other layers without departing from the spirit of the invention. Details of these other layers will be described later.

[0041] The infrared absorption layer 4 can be the outermost layer of the multilayer 1. By providing the infrared absorption layer 4, the surface hardness of the multilayer can often be further improved. In the multilayer 1 of this embodiment, it is preferable to stack the acrylic resin layer 2, the polycarbonate resin layer 3, and the infrared absorption layer 4 in that order, with the infrared absorption layer 4 located on the surface of the polycarbonate resin layer 3. By having the infrared absorption layer 2 located on the surface of the polycarbonate resin layer 3, the formability of the infrared absorption layer 2 (the coatability of the composition for forming the infrared absorption layer) can be further improved. As long as the multilayer of this embodiment stacks the acrylic resin layer 2, the polycarbonate resin layer 3, and the infrared absorption layer 4 in the above order, other layers may be present without departing from the spirit of this embodiment, but it is preferable that there are no other layers, that is, the above three layers are adjacent to each other.

[0042] Furthermore, the multilayer in this embodiment can be a flame-retardant substrate in which at least one of the acrylic resin layer and the polycarbonate resin layer contains 0.01 to 0.80% by mass of a sulfonate metal salt. By using such a flame-retardant substrate, it can also be applied to applications requiring flame retardancy. These details will be explained later.

[0043] The thickness (total thickness) of the multilayer is preferably, but not particularly limited to, 30 μm or more, more preferably 100 μm or more. In addition, the thickness of the multilayer is preferably 10,000 μm or less, more preferably 5,000 μm or less, and even more preferably 2,000 μm or less, and can be 1,000 μm or less or 500 μm or less.

[0044] The multilayer structure in this embodiment preferably exhibits excellent infrared shielding performance.

[0045] Specifically, the transmittance of the multilayer at a wavelength of 1000 nm in this embodiment is preferably 30% or less, more preferably 10% or less, further preferably 8% or less, and even more preferably 7% or less. Although no specific lower limit is specified, it is actually greater than 0%.

[0046] The multilayer material in this embodiment also preferably exhibits excellent transparency. Specifically, it is further preferred that the haze of the multilayer material is 3% or less, more preferably 2% or less, even more preferably 1.5% or less, and even more preferably 1% or less. Although the lower limit is preferably 0% or more, in practice it exceeds 0%.

[0047] The multilayer body of this embodiment may also have flame retardancy. Specifically, the multilayer body preferably meets the Class C rating in the flammability test (FMVSS test) based on FMVSS No. 302 (it is burning before reaching the B mark, but the burning rate is less than 102 mm / min), and more preferably meets the Class B rating in the FMVSS test (it self-extinguishes within 51 mm of the A mark (and within 60 seconds)).

[0048] The above-mentioned transmittance, haze, and FMVSS tests were performed according to the description in the following embodiments.

[0049] The multilayer structure of this embodiment preferably further includes a hard coating layer. Preferably, the hard coating layer is present on at least one side of the multilayer structure, more preferably on the side of the acrylic resin layer opposite to the polycarbonate resin layer. The hard coating layer can be the outermost surface layer of the multilayer structure. By providing a hard coating layer, the surface hardness of the multilayer structure can often be further improved. In the multilayer structure of this embodiment, the hard coating layer is preferably stacked in the order of infrared absorption layer, polycarbonate resin layer, acrylic resin layer, and hard coating layer. In the multilayer structure of this embodiment, the hard coating layer is preferably provided on the surface of the acrylic resin layer. By providing a hard coating layer on the surface of the acrylic resin layer, the coatability of the hard coating layer can be further improved.

[0050] The hard coating layer included in the multilayer of this embodiment may be a layer with a surface hardness higher than that of the polycarbonate resin layer. By including such a hard coating layer, the surface hardness of the multilayer and even the molded article can be improved.

[0051] The thickness of the hard coating is preferably 0.5 μm or more, more preferably 1 μm or more, further preferably 2 μm or more, even more preferably 2.5 μm or more, and still more preferably 3 μm or more. By setting the thickness above or below the above-mentioned lower limit, the overall pencil hardness of the multilayer body can often be further improved by using the hard coating. The upper limit of the thickness of the hard coating is preferably 20 μm or less, more preferably 15 μm or less, further preferably 12 μm or less, even more preferably 10 μm or less, and still more preferably 8 μm or less, and can be 5 μm or less. By setting the thickness below the above-mentioned upper limit, the flame retardancy can often be further improved.

[0052] The hard coating is preferably a layer obtained by applying a hard coating material that can be cured by heat curing or active energy rays and then curing it.

[0053] As an example of a coating that uses active energy rays for curing, a resin composition comprising one or more monofunctional or polyfunctional (preferably 2- to 10-functional) (meth)acrylate monomers or oligomers can be cited. A resin composition comprising monofunctional or polyfunctional (preferably 2- to 10-functional) urethane (meth)acrylate oligomers is preferred. In these resin compositions, a photopolymerization initiator is preferably added as a curing catalyst.

[0054] In addition, examples of thermosetting resin coatings include polyorganosiloxane-based and cross-linked acrylic coatings. These resin compositions are also commercially available as hard coating agents for acrylic resins or polycarbonate resin films or sheets, and can be appropriately selected based on their compatibility with the coating production line.

[0055] As a hard coating, reference can be made to the descriptions in Japanese Patent Application Publication No. 2013-020130, paragraphs

[0045] to

[0055] , Japanese Patent Application Publication No. 2018-103518, paragraphs

[0073] to

[0076] , and Japanese Patent Application Publication No. 2017-213771, paragraphs

[0062] to

[0082] , the contents of which are incorporated herein by reference.

[0056] The hard coating preferably includes, in addition to the above-mentioned components, inorganic particles, organic pigments, ultraviolet absorbers, light stabilizers, heat stabilizers, flame retardants, flame retardant additives, colorants, antistatic agents, fluorescent whitening agents, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact resistance improvers, slip resistance improvers, hue improvers, acid scavengers, leveling agents, etc., and more preferably, inorganic particles. One or more of these components may be used.

[0057] Examples of inorganic particles are preferably nanoparticles composed of metals and / or metal compounds. Examples include gold, silver, copper, platinum, palladium, nickel, cobalt, iron, manganese, silicon, titanium, zirconium, tungsten, molybdenum, chromium, zinc, aluminum, and composite metals composed of two or more of these metals. Furthermore, metal compounds are preferably metal oxides, metal carbides, metal borides, metal carbonates, zeolites, clays, and their complexes, such as iron oxide, silicon dioxide, zirconium oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, cobalt oxide, nickel oxide, cerium oxide, copper oxide, zinc oxide, tin oxide, antimony oxide, titanium dioxide, aluminum oxide, indium tin oxide (ITO), cesium tungsten oxide (CWO), and mixtures thereof; silicon dioxide is more preferred.

[0058] The aforementioned inorganic particles may or may not undergo surface treatment. Surface treatment is preferred. The surface treatment agent is preferably a silane coupling agent.

[0059] The average particle size D50 of the aforementioned 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 it above the aforementioned lower limit, the flame retardancy of the obtained multilayer body can often be further improved. In addition, by setting it below the aforementioned upper limit, the ratio of surface area to mass ratio increases, thereby enabling the formation of more cross-linked structures with other components.

[0060] In this embodiment, the content of inorganic particles in the hard coating is preferably 20 parts by mass or more, more preferably 30 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. By setting the content above the above-mentioned lower limit, the flame retardancy of the resulting multilayer can often be further improved. In addition, by setting the content below the above-mentioned upper limit, the generation of cracks during the heat resistance test of the multilayer can often be more effectively suppressed.

[0061] The aforementioned hard coating may contain only one type of inorganic particle or two or more types of inorganic particles. When containing two or more types, the total amount is preferably within the aforementioned range.

[0062] Examples of flame retardants include halogen-based flame retardants and phosphorus-based flame retardants. Examples of phosphorus-based flame retardants include aromatic phosphate compounds, phenanthrene phosphate compounds, phosphonate metal salts, ammonium polyphosphate, melamine polyphosphate, phosphate ester amides, and red phosphorus. For further information on flame retardants, please refer to paragraphs

[0054] to

[0082] of Japanese Patent Application Publication No. 2022-104214 and paragraphs

[0052] to

[0077] of Japanese Patent No. 7021724, the contents of which are incorporated herein by reference.

[0063] In addition to the above-described structure, the multilayer body of this embodiment may also have other layers. Examples include bonding layers, adhesive layers, antifouling layers, antireflective layers, and polarizing layers, with an antireflective layer being preferred.

[0064] The anti-reflective layer is typically preferably located on the opposite side of the infrared absorbing layer from the polycarbonate resin layer (e.g., Figure 1 It can be placed on the underside of 4, but it can also be placed on the polycarbonate (resin layer) side.

[0065] Details of the anti-reflective layer can be found in Japanese Patent Application Publication No. 2023-114940, paragraphs

[0062] to

[0083] , Japanese Patent Application Publication No. 2022-174051, paragraphs

[0013] to

[0041] , and Japanese Patent Application Publication No. 2021-081596, paragraphs

[0043] to

[0046] , the contents of which are incorporated herein by reference.

[0066] The polarizing layer is typically preferably located on the side of the infrared absorbing layer opposite to the polycarbonate resin layer (e.g., Figure 1 (of) 4 on the lower side.

[0067] Details of the polarizing layer can be found in Japanese Patent Application Publication No. 2008-105225, paragraphs

[0022] to

[0029] , Japanese Patent Application Publication No. 2020-52406, paragraphs

[0011] to

[0021] , and Japanese Patent Application Publication No. 2023-13533, paragraphs

[0014] to

[0037] , the contents of which are incorporated herein by reference.

[0068] Furthermore, the multilayer can also undergo one or more of the following treatments on at least one surface: fingerprint resistance treatment, anti-glare treatment, weather resistance treatment, antistatic treatment, anti-fouling treatment, and anti-blocking treatment. In addition, anti-blocking treatment refers to a treatment that allows the films to be easily peeled off even if they adhere to each other, and examples include adding anti-blocking agents and creating textures on the surface of the multilayer.

[0069] <Infrared Absorption Layer> The infrared absorbing layer in this embodiment comprises a UV-curable resin, a photopolymerization initiator, and a colorant. Furthermore, the UV-curable resin contains a component derived from a bifunctional (meth)acrylate monomer (A-1) having an alicyclic and / or aromatic ring, and the proportion of the component derived from the aforementioned monomer (A-1) in the infrared absorbing layer is 10–31% by mass. The colorant includes tungsten oxide, and the proportion of the aforementioned tungsten oxide in the infrared absorbing layer is 20% by mass or more. By employing this configuration, a multilayer with excellent weather resistance, adhesion, and transparency can be provided.

[0070] <<Bifunctional (meth)acrylate monomers with alicyclic and / or aromatic rings (A-1)>> The UV-curable resin contains a component derived from a bifunctional (meth)acrylate monomer (A-1) having an alicyclic and / or aromatic ring (sometimes referred to simply as "bifunctional (meth)acrylate monomer (A-1)" in this specification).

[0071] The components derived from the difunctional (meth)acrylate monomer (A-1) can be either the difunctional (meth)acrylate monomer (A-1) itself or its cured form. The difunctional (meth)acrylate monomer (A-1) contained in the ultraviolet absorbing layer is usually a cured form.

[0072] The weight-average molecular weight of the bifunctional (meth)acrylate monomer (A-1) is usually below 1000, preferably 200 to 1000.

[0073] The bifunctional (meth)acrylate monomer (A-1) contains alicyclic and / or aromatic rings. Due to the presence of alicyclic and / or aromatic rings and the relatively large skeleton volume, the resins readily interact with each other and stress relaxation is easily achieved. This results in easier adherence to other layers, improving adhesion.

[0074] The difunctional (meth)acrylate monomer (A-1) preferably has an aromatic ring. By using a difunctional (meth)acrylate monomer (A-1) containing an aromatic ring, especially the monomer represented by formula (1-1) and / or the monomer represented by formula (1-2), it is possible to improve compatibility with polycarbonate resins, facilitate the formation of a common layer, and improve adhesion.

[0075] Examples of alicyclic rings contained in the bifunctional (meth)acrylate monomer (A-1) include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, cycloheptane rings, cyclooctane rings, cyclononane rings, cyclodecane rings, cycloundecane rings, and cyclododecane rings. Examples of cyclic olefin rings include cyclopropene rings, cyclobutene rings, cyclopentene rings, cyclohexene rings, cycloheptene rings, cyclooctene rings, bicyclic undecane rings, decalin rings, norbornene rings, norbornadiene rings, tricyclic decane rings, cuboethane rings, shaleane rings, arsenane rings, and spirocyclic rings, with cyclohexane rings and tricyclic decane rings being preferred.

[0076] Examples of aromatic rings contained in the difunctional (meth)acrylate monomer (A-1) include benzene rings, naphthalene rings, anthracene rings, biphenyl rings, indene rings, azurite rings, and biphenylene rings, with benzene rings being preferred. Particularly preferred are difunctional (meth)acrylate monomers derived from bisphenols, further preferred are monomers represented by formula (1-1) and / or monomers represented by formula (1-2), and even more preferred are monomers represented by formula (1-1). In equations (1-1) and (1-2), n and m are independent numbers that satisfy the condition that n+m is greater than 3 and less than 5.

[0077] The content of the bifunctional (meth)acrylate monomer (A-1) in the infrared absorption layer is 10% by mass or more, and 31% by mass or less, preferably 27% by mass or less, more preferably 22% by mass or less, even more preferably 20% by mass or less, even more preferably 15% by mass or less, and still even more preferably 12% by mass or less. Setting the content above the lower limit often improves the adhesion of the coating film. Setting the content below the upper limit often improves the transparency of the resulting multilayer.

[0078] The infrared absorbing layer of this embodiment may contain only one bifunctional (meth)acrylate monomer (A-1), or it may contain two or more monomers (A-1). When it contains two or more monomers (A-1), the total amount is preferably within the above-mentioned range.

[0079] <<Other UV-curable resins>> The UV-curable resin used in this embodiment preferably includes other UV-curable resins besides those derived from the difunctional (meth)acrylate monomer (A-1) (sometimes referred to simply as "other UV-curable resins" in this specification).

[0080] There are no particular restrictions on the types of other UV-curable resins; any known resins may be used.

[0081] Other UV-curable resins include polymers containing (meth)acryloyl groups, polyfunctional urethane (meth)acrylate oligomers, etc., with polyfunctional urethane (meth)acrylate oligomers being preferred.

[0082] Polymers containing (meth)acryloyl groups can be synthesized, for example, by copolymerizing (meth)acrylic acid and glycidyl ether of (meth)acrylic acid to form an epoxy compound with a (meth)acrylate backbone, and then adding acrylic acid or methacrylic acid to it. Synthetic examples are shown below. Examples of epoxy (meth)acrylates used as polymers containing (meth)acryloyl groups include compounds having repeating units as shown in formula (I). In formula (I), m is an alkylene group or a single bond with 1 to 4 carbon atoms, n is an alkyl group or a hydrogen atom with 1 to 4 carbon atoms, p is a single bond or an alkylene group with 1 or 2 carbon atoms, and q is an alkyl group or a hydrogen atom with a total number of 1 to 12 carbon atoms that may contain at least one of the substituents of epoxy, hydroxyl, acryloyl and methacryloyl.

[0083] The epoxy (meth)acrylate polymer more preferably comprises the following repeating unit, namely, in the above formula (I), m is an alkylene group with 1 or 2 carbon atoms, n is an alkyl group with 1 or 2 carbon atoms, p is a single bond or methylene group, and q is a repeating unit with a total number of 1 to 6 alkyl or hydrogen atoms that may contain at least one of the substituents of glycidyl group, hydroxyl group and acryloyl group.

[0084] For example, in the above formula (I), m is methylene, n is methyl, p is a single bond, q is methyl, alkyl with 5 or fewer carbon atoms containing glycidyl (epoxy) group, alkyl with 8 or fewer carbon atoms containing hydroxyl and acryloyl group, etc.

[0085] Specific examples of repeating units contained in epoxy (meth)acrylate polymers include repeating units shown in formulas (II-a), (II-b), and (II-c). In the (meth)acrylate polymer, based on the total molar number of repeating units of formula (II-a), formula (II-b), and formula (II-c), the proportion of repeating units of formula (II-a) is preferably 30-85 mol%, more preferably 40-80 mol%. The proportion of repeating units of formula (II-b) is preferably 5-30 mol%, more preferably 10-25 mol%, based on the total molar number described above. Furthermore, the proportion of repeating units of formula (II-c) is preferably 10-40 mol%, more preferably 10-35 mol%, based on the total molar number described above.

[0086] Furthermore, the molar ratio of the repeating unit in formula (II-a), the repeating unit in formula (II-b), and the repeating unit in 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.

[0087] These polymers containing (meth)acryloyl groups are commercially available and readily available. Examples include SMP-220A (manufactured by Kyoeisha Chemical Co., Ltd.), SMP-250A (manufactured by Kyoeisha Chemical Co., Ltd.), SMP-360A (manufactured by Kyoeisha Chemical Co., Ltd.), SMP-550A (manufactured by Kyoeisha Chemical Co., Ltd.), HA7975 (manufactured by Showa Denko Materials Co., Ltd.), HA7975D (manufactured by Showa Denko Materials Co., Ltd.), RA-4101 (manufactured by Neage Kogyo Co., Ltd.), 8KX-078 (manufactured by Taisei Fine Chemicals Co., Ltd.), and 8KX-212 (manufactured by Taisei Fine Chemicals Co., Ltd.).

[0088] Examples of polyfunctional urethane (meth)acrylate oligomers include the urethane esterification reaction products of (meth)acrylate monomers having at least one (meth)acryloyloxy and one hydroxyl group in one molecule with polyisocyanates; and the urethane esterification reaction products of isocyanate compounds obtained by reacting polyols and polyisocyanates with (meth)acrylate monomers having at least one or more (meth)acryloyloxy and one or more hydroxyl groups in one molecule.

[0089] Examples of (meth)acrylate monomers used in carbamate reactions that have at least one (meth)acryloyloxy and one hydroxyl group in one molecule include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glyceryl di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, and pentaerythritol penta(meth)acrylate.

[0090] Examples of polyisocyanates used in carbamate reactions include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, phenyl diisocyanate, diisocyanates obtained by hydrogenation of aromatic isocyanates (e.g., hydrogenated toluene diisocyanate, hydrogenated phenyl diisocyanate, etc.), triphenylmethane triisocyanate, dimethylene triphenyl triisocyanate, etc., or polyisocyanates obtained by polymerizing diisocyanates.

[0091] Polyols used in urethane esterification reactions typically include, in addition to aromatic, aliphatic, and alicyclic polyols, polyester polyols and polyether polyols. Examples of aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, ethylene glycol, propylene glycol, trimethylolethane, trimethylolpropane, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyric acid, glycerol, and hydrogenated bisphenol A.

[0092] Examples of polyester polyols include products obtained through the dehydration condensation reaction of the aforementioned polyols with polycarboxylic acids. Specific compounds of polycarboxylic acids include succinic acid, adipic acid, maleic acid, trimellitic acid, hexahydrophthalic acid, phthalic acid, isophthalic acid, and terephthalic acid. These polycarboxylic acids can also be acid anhydrides. Furthermore, in addition to polyalkylene glycols, examples of polyether polyols include polyoxyalkylene modified polyols obtained by reacting the aforementioned polyols or phenols with epoxides.

[0093] Furthermore, multifunctional polyester (meth)acrylate oligomers are obtained through a dehydration condensation reaction of (meth)acrylic acid, polycarboxylic acids, and polyols. 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 can also be acid 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, dimethylolheptan, dimethylolpropionic acid, dimethylolbutyric acid, trimethylolpropane, bis(trimethylolpropane), pentaerythritol, and dipentaerythritol.

[0094] Multifunctional epoxy (meth)acrylate oligomers are 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.

[0095] As polyfunctional urethane (meth)acrylates, commercially available products can also be used. Examples include UN-3320HA, UN-3320HC, UN-906S, UN-901T, UN-952, UN-904, UN-905, UN-3320HS, H-575 (all manufactured by Negami Kogyo Co., Ltd.), U-6LPA, UA-1100H (all manufactured by Shin-Nakamura Chemical Co., Ltd.), EBECRYL5129, EBECRYL4738, EBECRYL4740, EBECRYL4513, EBECRYL8254, EBECRYL220, and EBECRYL8701 (all manufactured by Daicel Allnex Co., Ltd.).

[0096] The double bond equivalent of the UV-curable resin is 400 g / mol or less, preferably 360 g / mol or less, and more preferably 250 g / mol or less. Setting the value above or above this lower limit often improves the hardness of the resulting infrared absorption layer. As a lower limit, 100 g / mol or more is preferred.

[0097] The number of functional groups in other UV-curable resins is preferably 2 to 10, more preferably 3 to 7.

[0098] The weight-average molecular weight of other UV-curable resins is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, and even more preferably 1,000 to 30,000. Setting it above 1,000 can more effectively suppress curing shrinkage; setting it below 100,000 can make coating easier.

[0099] In this embodiment, the content of other UV-curable resins in the infrared absorption layer is preferably 30% by mass or more, more preferably 35% by mass or more, further preferably 40% by mass or more, even more preferably 45% by mass or more, and preferably 70% by mass or less, more preferably 65% ​​by mass or less, and even more preferably 60% by mass or less. By setting the content above the above-mentioned lower limit, multilayers with higher toughness and higher hardness can often be obtained. Furthermore, by setting the content below the above-mentioned upper limit, a coating film with a good balance between light transmittance and infrared absorption can be obtained.

[0100] The infrared absorbing layer of this embodiment may contain only one type of bifunctional (meth)acrylate monomer (A-1) and other UV-curable resins, or it may contain two or more types. When two or more types are contained, the total amount is preferably within the above-mentioned range.

[0101] <<Photopolymerization Initiators>> The photopolymerization initiator used in this embodiment can be any known photopolymerization initiator, as long as it can cure the UV-curable resin.

[0102] As a photopolymerization initiator, a photoradical initiator that can break bonds and generate free radicals under the action of visible light or ultraviolet light with a wavelength shorter than 450 nm is preferred. Examples include photopolymerization initiators having an acylphosphine oxide skeleton, an α-hydroxy ketone skeleton, a benzyl dimethyl ketal skeleton, an amino ketone skeleton, a benzophenone skeleton, or a triazine skeleton containing trichloromethyl. Photopolymerization initiators having an acylphosphine oxide skeleton and / or an α-hydroxy ketone skeleton are preferred.

[0103] Specific examples of photopolymerization initiators include benzophenone, thioxanone, benzyl dimethyl ketal, α-hydroxy ketone, α-hydroxyalkyl phenyl ketone, α-amino ketone, α-aminoalkyl phenyl ketone, monoacylphosphine oxide, diacylphosphine oxide, hydroxybenzophenone, aminobenzophenone, dicene, oxime ester, and oxyphenyl acetate.

[0104] In addition to the examples mentioned above, as polymerization initiators, references can also be made to the descriptions in International Publication No. 2023 / 095664, paragraph

[0039] ; International Publication No. 2022 / 102736, paragraphs

[0234] to

[0238] ; Japanese Patent Application Publication No. 2010-106268, paragraphs

[0135] onwards; Japanese Patent Application Publication No. 2009-13115, paragraphs

[0018] to

[0025] ; and Japanese Patent Application Publication No. 2005-154312, paragraphs

[0018] to

[0025] , the contents of which are incorporated herein by reference.

[0105] The content of the photopolymerization initiator contained in the infrared absorption layer of this embodiment is preferably 0.1% by mass or more, more preferably 1% by mass or more, further preferably 1.5% by mass or more, even more preferably 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 it above the above lower limit value, sufficient curability can be exhibited. By setting it below the above upper limit value, storage stability and aging degradation can often be further improved.

[0106] The infrared absorbing layer of this embodiment may contain only one photopolymerization initiator, or it may contain two or more. When it contains two or more, the total amount is preferably within the above-mentioned range.

[0107] <<Coloring Agents>> The colorant used in this embodiment includes tungsten oxide. By including tungsten oxide, the multilayer can block near-infrared light, thus making it more suitable for use as a dust cover for head-up displays.

[0108] Cesium tungsten oxide (CWO) is preferred as the tungsten oxide.

[0109] In this embodiment, the tungsten oxide content in the infrared absorption layer is preferably 20% by mass or more, more preferably 25% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 42% by mass or less. By setting the content above the lower limit, the infrared absorption effect can often be further improved. By setting the content below the upper limit, excellent transparency can be maintained.

[0110] The infrared absorbing layer of this embodiment may contain only one type of tungsten oxide, or it may contain two or more types. When it contains two or more types, the total amount is preferably within the above-mentioned range.

[0111] The colorant in this embodiment may also include colorants other than tungsten oxide, such as inorganic pigments and / or organic pigments or dyes other than tungsten oxide.

[0112] Examples of inorganic pigments include titanium dioxide, barium sulfate, zinc sulfide, and zinc oxide as white pigments; iron oxide and titanium yellow as yellow pigments; iron oxide as red pigments; cobalt blue and ultramarine as blue pigments; and carbon black as black pigments. Examples of organic pigments or dyes include monoazo, condensed azo, anthraquinone, diazo, and heterocyclic compounds as yellow pigments; quinacridone, anthraquinone, perylene, diazo, and monoazo as red pigments; phthalocyanine as blue pigments; and phthalocyanine as green pigments. These colorants can be used alone or in mixtures of two or more.

[0113] In the infrared absorption layer of this embodiment, the content of colorants other than tungsten oxide is usually 0 to 10% by mass, and the content of colorants in the infrared absorption layer is preferably less than 10% by mass, more preferably less than 5% by mass, and even more preferably less than 1% by mass.

[0114] <<Heat Stabilizers>> 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% by mass, more preferably 2 to 10.0% by mass. The heat stabilizer may contain only one type or two or more types. When two or more types are contained, the total amount is preferably within the above range. By setting the content above the lower limit, deterioration of the infrared absorbing layer during damp heat testing can be prevented.

[0115] <<Other Ingredients>> In addition to the components mentioned above, the infrared absorbing layer may also contain leveling agents, ultraviolet absorbers, light stabilizers, flame retardants, flame retardant additives, antistatic agents, fluorescent whitening agents, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, anti-blocking agents, impact resistance improvers, slip resistance improvers, color improvers, acid scavengers, etc. One or more of these components may be used.

[0116] The total amount of these other components in the infrared absorption layer is preferably 0% or more and less than 10% by mass, more preferably 0% or more and less than 5% by mass, and may also be 0% or more and less than 1% by mass.

[0117] <<Light Stabilizers>> As light stabilizers, hindered amine light stabilizers such as bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate, bis(1-undecalkoxy-2,2,6,6-tetramethylpiperidin-4-yl) carbonate, 1,2,2,6,6-13-pentamethyl-4-piperidinyl methacrylate, 2,2,6,6-tetramethyl-4-piperidinyl methacrylate, bis[2,2,6,6-tetramethyl-1-(octoxy)piperidin-4-yl] sebacate, and 2-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]-2-butylmalonic acid bis[1,2,2,6,6-pentamethyl-4-piperidinyl] ester can be used.

[0118] The content ratio of light stabilizer in the infrared absorption layer is preferably 0-5% by mass, more preferably 0-3% by mass, and even more preferably 0-1% by mass. By setting it below the above upper limit, the UV-curable resin can often be cured more effectively.

[0119] Examples of flame retardants include halogen-based flame retardants and phosphorus-based flame retardants. Examples of phosphorus-based flame retardants include aromatic phosphate compounds, phenanthrene phosphate compounds, phosphonate metal salts, ammonium polyphosphate, melamine polyphosphate, phosphate ester amides, and red phosphorus. For further information on flame retardants, please refer to paragraphs

[0054] to

[0082] of Japanese Patent Application Publication No. 2022-104214 and paragraphs

[0052] to

[0077] of Japanese Patent No. 7021724, the contents of which are incorporated herein by reference.

[0120] In the infrared absorption layer, the total amount of ultraviolet-curable resin, photopolymerization initiator and colorant preferably accounts for more than 90% by mass, more preferably more than 95% by mass, and even more preferably more than 97% by mass.

[0121] In addition, the total amount of UV-curable resin, photopolymerization initiator and colorant in the infrared absorption layer will not exceed 100% by mass.

[0122] The thickness of the infrared absorption layer is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 1.5 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, even more preferably 5 μm or less. By setting it below the above upper limit value, curing defects will not occur during UV curing. By setting it above the above lower limit value, the effect as an infrared absorption layer can be more effectively demonstrated.

[0123] <Polycarbonate resin layer> The polycarbonate resin layer in this embodiment contains polycarbonate resin.

[0124] There are no particular limitations on the polycarbonate resin, and various polycarbonate resins can be used, as long as they include the -[O-R-OCO]- structural unit (R is a hydrocarbon group, such as aliphatic group, aromatic group, or both aliphatic group and aromatic group, and has a straight chain structure or a branched chain structure) in the main molecular chain. Aromatic polycarbonate resins are preferred.

[0125] In this embodiment, the polycarbonate resin preferably comprises 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 its derivatives. Bisphenol and / or its derivatives are preferably bisphenol A, bisphenol AP, bisphenol C, bisphenol BP, or derivatives of these bisphenols, more preferably bisphenol A, bisphenol AP, or derivatives of both, and even more preferably bisphenol A or its derivatives.

[0126] Bisphenol type polycarbonate resin is preferably bisphenol A type polycarbonate resin.

[0127] The molecular weight of polycarbonate resin is typically calculated by converting the viscosity of the solution measured at 25°C using dichloromethane as a solvent. Preferably, but not particularly limited to, it is 20,000 or more, more preferably 22,000 or more. Furthermore, the aforementioned 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 above, the strength of the obtained flat molded body can be improved. Moreover, by setting the viscosity-average molecular weight to the upper limit or below, the molding and processing performance is often improved.

[0128] Wherein, viscosity-average molecular weight [Mv] refers to the intrinsic viscosity [η] (unit: dL / g) at 25°C using dichloromethane as a solvent and an Ubbelohde viscometer, based on the Schnell viscosity formula, i.e., η = 1.23 × 10⁻⁶. ﹣4 Mv 0.83 The calculated value. Furthermore, intrinsic viscosity [η] refers to the specific viscosity [η] measured at various solution concentrations [C] (g / dL). sp ], and the value is calculated according to the following formula. It should be noted that, in this embodiment, two or more polycarbonate resins with different viscosity-average molecular weights can be mixed and used. In this case, the viscosity-average molecular weight of the mixture is used.

[0129] The initial glass transition temperature (Tg) of the polycarbonate resin used in this embodiment is preferably 160°C or less, more preferably 155°C or less, even more preferably 154°C or less, even more preferably 153°C or less, even more preferably 152°C or less, and even more preferably 151°C or less. Furthermore, the initial glass transition temperature (Tg) of the polycarbonate resin used in this embodiment is, for example, 140°C or more, and further preferably 143°C or more, 145°C or more, 147°C or more, or 148°C or more.

[0130] The glass transition temperature was measured according to the description in paragraph

[0056] of Japanese Patent Application Publication No. 2022-080270.

[0131] Furthermore, as long as the main idea of ​​this embodiment is not deviated from, the details of the polycarbonate resin can also be found in paragraphs

[0011] to

[0020] of Japanese Patent Application Publication No. 2012-144604 and paragraphs

[0014] to

[0035] of Japanese Patent Application Publication No. 2019-002023, which are incorporated herein by reference.

[0132] The content of polycarbonate resin in the polycarbonate resin layer of this embodiment is preferably 90% by mass or more, more preferably 92% by mass or more, further preferably 94% by mass or more, even more preferably 96% by mass or more, and even more preferably 97% by mass or more, and can be 98% by mass or more. The upper limit can be 100% by mass.

[0133] In this embodiment, when the polycarbonate resin layer contains two or more types of polycarbonate resin, it is preferable that their total amount is within the above-mentioned range.

[0134] The polycarbonate resin layer in this embodiment may also contain sulfonate metal salts. Sulfonate metal salts are typically used as flame retardants in polycarbonate resins.

[0135] The sulfonate metal salt is preferably an alkali metal salt. Lithium, sodium, potassium, and rubidium are preferred as the alkali metal constituting the alkali metal salt, with sodium and potassium being more preferred. Additionally, the sulfonate metal salt may also contain fluorine atoms.

[0136] The molecular weight of the sulfonate metal salt used in this embodiment is preferably 100-900, more preferably 100-500.

[0137] Specific examples of the sulfonate metal salts used in this embodiment are shown below. It goes without saying that the sulfonate metal salts used in this embodiment are not limited to these. The content of 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. Depending on the application, it may be less than 0.1% by mass or less than 0.05% by mass.

[0138] The polycarbonate resin layer of this embodiment may contain only one sulfonate metal salt, or it may contain two or more sulfonate metal salts. When it contains two or more, the total amount is preferably within the above-mentioned range.

[0139] The polycarbonate resin layer in this embodiment may also contain flame retardants other than sulfonate metal salts, such as phosphorus-based flame retardants like condensed phosphate esters and phosphazenes, organosilicon-based flame retardants like polyorganosiloxanes, and halogen-based flame retardants like Br-modified polycarbonate oligomers. Specific examples of phosphorus-based flame retardants include condensed phosphate esters such as resorcinol bis(diphenyl phosphate) (RDP), resorcinol bis(xylyl 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, more preferably 0.5 to 10% by mass.

[0140] The polycarbonate resin layer of this embodiment may also contain ultraviolet absorbers such as triazine-based ultraviolet absorbers and benzotriazole-based ultraviolet absorbers. The content of the ultraviolet absorber in the polycarbonate resin layer is preferably 0.1 to 5.0% by mass, more preferably 0.5 to 2.0% by mass.

[0141] In addition to the components described above, the polycarbonate resin layer of this embodiment may also contain antioxidants, release agents, flame retardants, heat stabilizers, colorants, antistatic agents, fluorescent whitening agents, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact resistance improvers, slip resistance improvers, hue improvers, acid scavengers, etc. One or more of these components may be used. The preferred content of the above components, in total, is 0-5% by mass of the polycarbonate resin layer; more preferably, 0-3% by mass; further preferably, 0-1% by mass; even more preferably, 0-0.5% by mass; still more preferably, 0-0.3% by mass; and still more preferably, 0-0.1% by mass.

[0142] Examples of antioxidants include phenolic antioxidants, amine antioxidants, phosphorus-based antioxidants, and thioether antioxidants. In this embodiment, phosphorus-based antioxidants and phenolic antioxidants (more preferably hindered phenolic antioxidants), and even more preferably phosphorus-based antioxidants, are preferred.

[0143] The phosphorus-based antioxidant is preferably a phosphite antioxidant, and more preferably a phosphite compound represented by formula (1) or (2).

[0144] (1) In equation (1), R 11 and R 12 Each can be independently represented as an alkyl group with 1 to 30 carbon atoms or an aryl group with 6 to 30 carbon atoms. In equation (2), R 13 ~R 17 Each can be independently represented by a hydrogen atom, an aryl group with 6 to 20 carbon atoms, or an alkyl group with 1 to 20 carbon atoms.

[0145] In the above equation (1), R 11 R 12 Each alkyl group is preferably a straight-chain or branched alkyl group having 1 to 10 carbon atoms. In R 11 R 12 When the aryl group is aryl, it is preferably represented by any one of the following formulas (1-a), (1-b), and (1-c). The "*" in the formula indicates the bonding position. In equation (1-a), R A Each of the following independently represents an alkyl group having 1 to 10 carbon atoms. In formula (1-b), R B Each can be used independently to represent an alkyl group having 1 to 10 carbon atoms.

[0146] As a hindered phenolic antioxidant, reference can be made to paragraphs

[0063] of Japanese Patent Application Publication No. 2018-090677 and

[0076] of Japanese Patent Application Publication No. 2018-188496, the contents of which are incorporated herein by reference.

[0147] In addition to the compounds mentioned above, antioxidants can be found in paragraphs

[0057] to

[0061] of Japanese Patent Application Publication No. 2017-031313, the contents of which are incorporated herein by reference.

[0148] The antioxidant content is preferably 0.001 parts by weight or more, more preferably 0.005 parts by weight or more, further preferably 0.010 parts by weight or more, and even more preferably 0.050 parts by weight or more, relative to 100 parts by weight of the polycarbonate resin layer. Furthermore, as an upper limit for the antioxidant content, relative to 100 parts by weight of the polycarbonate resin layer, it is preferably 0.500 parts by weight or less, more preferably 0.300 parts by weight or less, further preferably 0.200 parts by weight or less, even more preferably 0.150 parts by weight or less, even more preferably 0.100 parts by weight or less, and particularly more preferably 0.080 parts by weight or less.

[0149] Antioxidants may be used in single or multiple forms. When using multiple forms, it is preferable that their combined dosage is within the range described above.

[0150] Next, we will explain the release agents that can be included in the polycarbonate resin layer.

[0151] Types of mold release agents can be listed, but are not specifically limited to, 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.

[0152] Details of the release agent can be found in paragraphs

[0035] to

[0039] of International Publication No. 2015 / 190162, the contents of which are incorporated herein by reference.

[0153] The content of the release agent relative to 100 parts by weight of the polycarbonate resin layer is preferably 0.001 parts by weight or more, more preferably 0.005 parts by weight or more, further preferably 0.010 parts by weight or more, and even more preferably 0.050 parts by weight or more. As an upper limit, it is preferably 0.5 parts by weight or less, more preferably 0.3 parts by weight or less, and even more preferably 0.1 parts by weight or less.

[0154] A single type of release agent may be used, or two or more may be used. When using two or more, it is preferable that their total dosage be within the range described above.

[0155] 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 setting it above the above lower limit, it is not only easier to mold, but also tends to improve flame retardancy. In addition, 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.

[0156] <Acrylic resin layer> The acrylic resin layer in this embodiment contains acrylic resin.

[0157] Furthermore, the acrylic resin layer can be a single layer or multiple layers, but a single layer is preferred.

[0158] The acrylic resin layer in this embodiment comprises acrylic resin as described above.

[0159] An example of an acrylic resin is preferably a polymer in which the content of (meth)acrylate alkyl ester units (preferably alkyl methacrylate units) in all structural units is 50% by mass or more (preferably 90% by mass or more), and more preferably a polymer in which the content of (meth)acrylate methyl acrylate units (preferably methyl methacrylate units) in all structural units is 50% by mass or more (preferably 90% by mass or more). Other structural units besides (meth)acrylate alkyl ester units can be cited as examples, such as other (meth)acrylate units, styrene units, cyclic anhydride units, N-substituted maleimide units, and lactone ring units.

[0160] The acrylic resin layer may be formed solely of acrylic resin, or it may contain other thermoplastic resins in addition to acrylic resin.

[0161] As other thermoplastic resins, it is more preferable to include at least one thermoplastic resin selected from styrene-based resins, fluorinated resins such as polyvinylidene fluoride, and aromatic polyether resins such as polyphenylene ether, and even more preferably to include styrene-based resins.

[0162] An example of an acrylic resin layer is a layer in which 90% or more (preferably 95% or more, more preferably 97% or more, and even more preferably 98% or more) is formed of acrylic resin.

[0163] Another example of an acrylic resin is a layer formed of the above-mentioned acrylic resin and other thermoplastic resins (preferably styrene-based resins) comprising 90% or more by mass (preferably 95% or more by mass, more preferably 97% or more by mass, and even more preferably 98% or more by mass).

[0164] The weight-average molecular weight of the acrylic resin is preferably, but not particularly limited to, 10,000 or more, more preferably 30,000 or more, further preferably 50,000 or more, even more preferably 60,000 or more, and still more preferably 70,000 or more. Furthermore, the weight-average molecular weight of the acrylic resin is preferably 250,000 or less, more preferably 200,000 or less, further preferably 150,000 or less, even more preferably 100,000 or less, and still even more preferably 90,000 or less.

[0165] 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 still more preferably 105°C or higher. There is no particular upper limit, but in practice it is, for example, 200°C or lower.

[0166] The glass transition temperature was measured according to the description in paragraph

[0056] of Japanese Patent Application Publication No. 2022-080270.

[0167] In addition to the above-mentioned components, the acrylic resin layer may also contain ultraviolet absorbers, antioxidants, release agents, inorganic particles, heat stabilizers, flame retardants, flame retardant additives, colorants, antistatic agents, fluorescent whitening agents, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, anti-blocking agents, impact resistance improvers, slip resistance improvers, color improvers, acid scavengers, etc. One or more of these components may be used. The preferred content of the above components, calculated in total, is 0-5% by mass of the acrylic resin layer; more preferably 0-3% by mass; further preferably 0-1% by mass; even more preferably 0-0.5% by mass; still more preferably 0-0.3% by mass; and even more preferably 0-0.1% by mass.

[0168] <<Ultraviolet Absorbers>> As described above, in order to prevent ultraviolet degradation of the polycarbonate resin layer, acrylic resin layer and infrared absorption layer in this embodiment, the acrylic resin layer in this embodiment may contain an ultraviolet absorber.

[0169] Examples of usable ultraviolet absorbers include benzotriazole, benzophenone, phenyl salicylate, benzoxazine, malonate, triazine, and polymeric ultraviolet absorbers with the above compounds added as side groups.

[0170] Examples of benzotriazole-based ultraviolet absorbers include 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2,2-methylenebis[4-(1,1,3,3-tetramethylenebutyl)-6-(2H-benzotriazole-2-yl)phenol], and 2-(2H-benzotriazole-2-yl)phenol. Examples include triazol-2-yl)-6-(1-methyl-1-phenethyl)-4-(1,1,3,3-tetramethylbutyl)phenol; examples of benzophenone-based ultraviolet absorbers include 2-hydroxy-4-octoxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-4'-chlorobenzophenone, 2,2-dihydroxy-4-methoxybenzophenone, and 2,2-dihydroxy-4,4'-dimethoxybenzophenone.

[0171] In addition, examples of phenyl salicylate-based ultraviolet absorbers include p-tert-butyl salicylate. Examples of benzoxazine-based ultraviolet absorbers include 2,2'-(1,4-phenylene)bis[4H-3,1-benzoxazine-4-one].

[0172] Examples of malonate-based ultraviolet absorbers include dimethyl [(4-methoxyphenyl)-methylene]malonate.

[0173] Examples of triazine-based ultraviolet absorbers include 2,4-diphenyl-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-ethoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-(2-hydroxy-4-propoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, and 2,6-di(4-biphenyl)-4-(2-hydroxy-4-(2-ethylhexyl)oxy Examples of triazine include (-phenylene)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-dodecanoyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine, and 2,4-diphenyl-6-(2-hydroxy-4-butoxyethoxy)-1,3,5-triazine, but these are not limited to these examples; they also include commonly available ultraviolet absorbers.

[0174] Examples of polymeric ultraviolet absorbers include polymers with hydroxybenzophenone or hydroxybenzotriazole structures, as well as substituted products in which some hydrogen atoms are replaced by alkyl groups. One example of a polymeric ultraviolet absorber is UVA-633L (2-hydroxy-4-(methacryloyloxyethoxy)benzophenone) methyl methacrylate copolymer, commercially manufactured by BASF.

[0175] Antioxidants As described above, the acrylic resin layer in this embodiment may contain an antioxidant. Examples of antioxidants include phenolic antioxidants, amine antioxidants, phosphorus-based antioxidants, and thioether antioxidants. In this embodiment, a phosphorus-based antioxidant is also preferred.

[0176] The phosphorus-based antioxidant is preferably a phosphite antioxidant, and more preferably a phosphite compound represented by formula (1) or (2).

[0177] (1) In equation (1), R 11 and R 12 Each can be independently represented as an alkyl group with 1 to 30 carbon atoms or an aryl group with 6 to 30 carbon atoms. In equation (2), R 13 ~R 17 Each can be independently represented by a hydrogen atom, an aryl group with 6 to 20 carbon atoms, or an alkyl group with 1 to 20 carbon atoms.

[0178] In the above equation (1), R 11 R 12 The alkyl groups represented are preferably each a straight-chain or branched alkyl group having 1 to 10 carbon atoms. In R 11 R 12 When the aryl group is aryl, it is preferably represented by any one of the following formulas (1-a), (1-b), and (1-c). The "*" in the formula indicates the bonding position. Relative to 100 parts by weight of the acrylic resin layer, the content of the antioxidant is preferably 0.001 parts by weight or more, more preferably 0.005 parts by weight or more, and even more preferably 0.010 parts by weight or more. As for the upper limit of the antioxidant content, relative to 100 parts by weight of the acrylic resin layer, it is preferably 0.500 parts by weight or less, more preferably 0.300 parts by weight or less, even more preferably 0.200 parts by weight or less, even more preferably 0.150 parts by weight or less, even more preferably 0.100 parts by weight or less, and even more preferably 0.080 parts by weight or less.

[0179] Antioxidants may be used in single or multiple forms. When using multiple forms, it is preferable that their combined dosage is within the range described above.

[0180] <<Mold Release Agent>> As described above, the acrylic resin layer in this embodiment may contain a release agent.

[0181] Types of mold release agents can be listed, but are not specifically limited to, 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.

[0182] Details of the release agent can be found in paragraphs

[0035] to

[0039] of International Publication No. 2015 / 190162, the contents of which are incorporated herein by reference.

[0183] The content of the release agent relative to 100 parts by weight of the acrylic resin layer is preferably 0.001 parts by weight or more, more preferably 0.005 parts by weight or more, further preferably 0.010 parts by weight or more, and even more preferably 0.050 parts by weight or more. As an upper limit, it is preferably 0.5 parts by weight or less, more preferably 0.3 parts by weight or less, and even more preferably 0.2 parts by weight or less.

[0184] A single type of release agent may be used, or two or more may be used. When using two or more, it is preferable that their total dosage be within the range described above.

[0185] As described above, the acrylic resin layer in this embodiment may contain inorganic particles. Examples of inorganic particles include silica particles, alumina particles, zirconium oxide particles, silicon particles, silver particles, and glass particles.

[0186] As described above, the acrylic resin layer in this embodiment may contain a flame retardant. Examples of flame retardants that can be included in the acrylic resin layer include phosphorus-based flame retardants and sulfonate metal salts, with phosphorus-based flame retardants being preferred.

[0187] Examples of phosphorus-based flame retardants include aromatic phosphate compounds, phosphazene compounds, phosphazene compounds, phosphonate metal salts, ammonium polyphosphate, melamine polyphosphate, phosphate ester amides, and red phosphorus, with aromatic phosphate compounds, phosphazene compounds, and phosphazene compounds being preferred.

[0188] Examples of aromatic phosphate compounds include resorcinol diphenyl phosphate, hydroquinone diphenyl phosphate, bisphenol A diphenyl phosphate, and biphenyl diphenyl phosphate. Commercially available examples 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.

[0189] Examples of aromatic phosphate compounds include cyclic phenoxyphosphazenes and their derivatives. Commercially available examples include Rabitle FP-110 manufactured by Fushimi Pharmaceutical Co., Ltd.

[0190] Phosphenanthrene compounds are phosphorus-based flame retardants with at least one phosphenanthrene skeleton in the molecule. Commercially available products include HCA, HCA-HQ, BCA, SANKO-220, and M-Ester manufactured by Sanko Corporation.

[0191] Phosphonic acid metal salts are phosphonates and / or diphosphonates and / or polymers thereof. Examples of such salts include salts of calcium, aluminum, and zinc. Commercially available phosphonic acid metal salts include Clariant's "Exolit" (registered trademark) OP1230 and OP1240.

[0192] Phosphate ester amides are aromatic amide flame retardants containing phosphorus and nitrogen atoms. Among commercially available phosphate ester amides, SP-703 manufactured by Shikoku Kasei Corporation is preferred.

[0193] Examples of ammonium polyphosphates include ammonium polyphosphate, melamine-modified ammonium polyphosphate, and carbamoyl ammonium polyphosphate. Examples of melamine polyphosphates include melamine phosphate, melamine pyrophosphate, and phosphates formed with melamine, melamine, and melamine. MPP-A manufactured by Sanwa Chemical Co., Ltd., PMP-100 manufactured by Nissan Chemical Co., Ltd., and PMP-200 manufactured by Nissan Chemical Co., Ltd. are preferred.

[0194] When the acrylic resin layer contains a flame retardant (phosphorus-based flame retardant, sulfonate metal salt, or other flame retardant), its content relative to 100 parts by weight of the acrylic resin layer is preferably 1 part by weight or more, more preferably 2 parts by weight or more, further preferably 5 parts by weight or more, and even more preferably 7 parts by weight or more. Furthermore, relative to 100 parts by weight of the acrylic resin layer, the upper limit of the content of the aforementioned flame retardant is preferably 25 parts by weight or less, more preferably 20 parts by weight or less, and even more preferably 15 parts by weight or less.

[0195] The acrylic resin layer may contain only one flame retardant or two or more. When containing two or more flame retardants, the total amount is preferably within the range described above.

[0196] 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 setting it above the above lower limit, it is not only easier to achieve molding, but also often the hardness can be improved. In addition, 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.

[0197] <Manufacturing Methods of Multilayer Materials> The multilayer body of this embodiment can be manufactured according to known methods.

[0198] The multilayer body of this embodiment can be manufactured by using a main extruder for extruding a polycarbonate resin layer forming composition and an auxiliary extruder for extruding an acrylic resin layer forming composition, melting and extruding the resin according to the conditions of each resin used, guiding it to a die, stacking it inside the die and forming it into a sheet, or stacking it after forming it into a sheet, to form a substrate. Then, an infrared absorption layer forming composition is coated on one side of the polycarbonate resin layer of the above-mentioned substrate and cured.

[0199] The multilayer body of this embodiment can be used directly or can be processed, especially by heating, to form a molded product.

[0200] <Applications> The multilayer body of this embodiment can be applied to optical components, appearance design products, anti-reflective molded bodies, etc.

[0201] The multilayer body of this embodiment can be applied to components of display devices, electrical and electronic equipment, OA (office automation) equipment, portable information terminals, mechanical parts, home appliances, vehicle parts, various containers, lighting equipment, etc. It is particularly suitable for housings of various displays, electrical and electronic equipment, OA equipment, portable information terminals, and home appliances; surface films of lighting equipment and vehicle parts (especially automotive interior parts); optical materials of smartphones and touchscreens; and optical discs. The multilayer body of this embodiment is especially preferred for use as a dust cover for head-up displays.

[0202] Example The following examples illustrate the present invention in more detail. The materials, dosages, ratios, processing contents, and processing steps shown in the following examples can be appropriately modified as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[0203] When the measuring instruments used in the embodiments are difficult to obtain due to reasons such as production stoppage, other devices with equivalent performance can be used for measurement.

[0204] 1. Raw materials Carbamate acrylate: UN-3320HC, solid content 100% by mass, weight average molecular weight 1500, functional group number 6, manufactured by Nejou Kogyo Co., Ltd.

[0205] BP4EAL: Bisphenol A EO adduct diacrylate, solid content 100% by mass, molecular weight 512, functional group number 2, manufactured by Kyoei Chemical Co., Ltd. DCP-A: Tricyclodecanedimethylethanol diacrylate, solid content 100% by mass, molecular weight 304, functional group number 2, manufactured by Shin-Nakamura Chemical Co., Ltd. CD406: Cyclohexanediethanol diacrylate, solid content 100% by mass, molecular weight 252, functional group number 2, Sartomer Chemicals Ltd.

[0206] PO-A: Phenoxyethyl acrylate, 100% solid content, molecular weight 192, number of functional groups 1, Kyoei Chemical Co., Ltd. TAI: Tris(2-acryloyloxyethyl)isocyanurate, solid component 100% by mass, molecular weight 423, functional group number 3, Tokyo Chemical Industry Co., Ltd. Esacure One: α-hydroxyketoylphosphine oxide photopolymerization initiator, 100% solid component, manufactured by IGM RESINSB.V.

[0207] Omnirad 819: Acylphosphine oxide photopolymerization initiator, solid component 100% by mass, manufactured by IGM RESINS BV.

[0208] YMF-02A: CWO (cesium tungsten oxide) dispersion, CWO content 18.5% by mass, manufactured by Sumitomo Metal Mining Co., Ltd.

[0209] Disperse Yellow 160: A yellow dye manufactured by Yuhon Chemical Industry Co., Ltd.

[0210] Solvent Red 27: A red dye manufactured by Oriental Chemical Industry Co., Ltd.

[0211] FeOOH-based pigments: Yellow pigments, produced using a pre-formed propylene glycol monomethyl ether (PGM) dispersion. Solid content: 20% by weight.

[0212] Pigment Red 254 series pigment: A red pigment made from a pre-formed methyl isobutyl ketone (MIBK) dispersion. Solid content 20% by mass. Manufactured by Nikko BICS Co., Ltd.

[0213] PC / PMMA membrane: A double-layer membrane consisting of a polycarbonate resin layer and an acrylic resin layer, DF02U, manufactured by Mitsubishi Gas Chemical Co., Ltd., with a thickness of 0.375 mm.

[0214] PC film: Polycarbonate monolayer film FS-2000, manufactured by Mitsubishi Gas Chemical Co., Ltd., thickness 0.200mm.

[0215] The flame-retardant substrate 1 and flame-retardant substrate 2 are structured as shown below.

[0216] [Table 1] E-2000F: A polycarbonate resin obtained by interfacial polymerization using bisphenol A as the starting material (Mitsubishi Gas Chemical Co., Ltd. E-2000F, viscosity-average molecular weight: 27000, Tg: 150℃).

[0217] S-3000F: A polycarbonate resin obtained by interfacial polymerization using bisphenol A as the starting material (Mitsubishi Gas Chemical Co., Ltd. S-3000F, viscosity-average molecular weight: 21000, Tg: 147℃).

[0218] KSS-FR: Manufactured by Arichem, KSS-FR stands for potassium diphenyl sulfone-3-sulfonate.

[0219] 2112: Tris(2,4-di-tert-butylphenyl) phosphite (phosphorus antioxidant, ADEKA stab2112 manufactured by ADEKA).

[0220] S-100A: Glyceryl monostearate (RIKEMAL S-100A manufactured by Riken Vitamin Co., Ltd.).

[0221] 80HD: Made by Asahi Kasei Co., Ltd., polymethylmethacrylate.

[0222] Tinuvin 1600: Manufactured by BASF, a triazine-based ultraviolet absorber.

[0223] PEP36: Manufactured by ADEKA Corporation, a phosphite-based antioxidant.

[0224] H-100: Riken Vitamin Co., Ltd., Glyceryl monostearate.

[0225] <Manufacturing of Flame-Retardant Substrates> Polycarbonate resin layer (PC layer) forming resin composition (granules) and acrylic resin layer forming resin composition (granules) were manufactured according to the following method. The components were weighed according to the addition amounts described in Table 1 (each component in Table 1 is expressed as a percentage by mass). Then, after mixing with a tumbler for 15 minutes, the mixture was melt-blended using a vented twin-screw extruder ("TEX30α" manufactured by Nippon Steel Co., Ltd., with a screw diameter of 32 mm, and the mixture was cut into granules. It should be noted that the polycarbonate resin layer forming resin composition (granules) was melt-blended at a temperature that varied from 260 to 300°C depending on the resin viscosity, while the acrylic resin layer forming resin composition (granules) was melt-blended at 260°C.

[0226] A multi-layer extrusion unit was used, consisting of a single-screw extruder with a shaft diameter of 32 mm, a single-screw extruder with a shaft diameter of 65 mm, a feeding unit connected to all extruders, and a 650 mm wide T-die connected to the feeding unit, to form flame-retardant substrates. The acrylic resin layer resin compositions (granules) for each flame-retardant substrate shown in Table 1 were introduced into the single-screw extruder with a shaft diameter of 32 mm, and extrusion was performed at a barrel temperature of 240°C and a discharge rate of 0.3–6.4 kg / h. Furthermore, the polycarbonate resin layer forming resin compositions (granules) for each flame-retardant substrate shown in Table 1 were continuously introduced into the single-screw extruder with a shaft diameter of 65 mm, and extrusion was performed at a discharge rate of 17.4–23.5 kg / h, with the barrel temperature varying in the range of 250–290°C according to the resin viscosity. The feeding unit connected to all extruders was equipped with two types of double-layer distributors (distribution pins), and extrusion and stacking were performed. The material is extruded into sheets using a T-shaped die connected to the front end of the extruder. Simultaneously, it is mirror-transferred using three mirror-polishing rollers with temperatures set at 120°C, 120°C, and 140°C from the upstream side, while being cooled to obtain various flame-retardant substrates.

[0227] 2. Examples 1-3, Comparative Examples 1-8 Fabrication of Multilayers (Coating of Infrared Absorption Layers) Components (A), (A-1), (B), and (C) shown in Tables 2-1, 2-2, 2-3, and 3 were mixed and stirred to obtain a composition for forming an infrared absorption layer. In Tables 2-1, 2-2, 2-3, and 3, the proportions of each component represent the amount of solid component.

[0228] The infrared absorption layer forming composition obtained above was applied to the substrates shown in Tables 2-1, 2-2, 2-3, and 3 using a doctor blade coater. The coated infrared absorption layer forming composition was dried in an oven at 80°C for 3 minutes and then cured under nitrogen atmosphere using a Heraeus UV irradiation system until the cumulative light intensity reached 500 mJ / cm². 2 (UV illuminance meter manufactured by ORC, measuring wavelength 360nm).

[0229] <Hard coating on the opposite side> A hard coating is applied to the side of the multilayer body fabricated as described above, opposite to the side with the infrared absorption layer.

[0230] In Tables 2-1 and 2-2, a and b represent the resin compositions used for hard coating formation, specifically the following substances.

[0231] a: Fujikura Chemicals HO3313U-10 b: A resin composition for hard coating prepared by mixing 67.5% by mass of Genjo Industrial's UN-3320HC, 29.0% by mass of silica particles surface-treated with 3-acryloyloxypropyltrimethoxysilane, 2.5% by mass of photopolymerization initiator, and 1% by mass of leveling agent.

[0232] The above-mentioned hard coating resin composition was applied to the outermost surface (the surface of the acrylic resin layer) of the multilayer, opposite to the side containing the infrared absorbing layer, using a doctor blade coater. The applied hard coating resin composition was dried in an oven at 80°C for 3 minutes and then cured under nitrogen atmosphere using a Heraeus UV irradiation system until the cumulative light intensity reached 500 mJ / cm². 2 (Using an ORC UV illuminometer with a measurement wavelength of 360nm), a hard coating with a thickness of 4μm was formed.

[0233] <Haze in Multi-layered Structures> The haze of the multilayer was evaluated according to JIS K 7136:2000. The haze was measured using the "HM-150" manufactured by the Murakami Color Technology Research Institute in Japan.

[0234] <Transmittance at 1000nm wavelength (%)> The transmittance at a wavelength of 1000 nm was measured.

[0235] The transmittance was measured using a Hitachi High Technology Co., Ltd. U-4000 spectrophotometer.

[0236] <Boiling Water Adhesion> The multi-layer body was immersed in boiling water (100 °C), fished out after 30 minutes, and the adhesion between the substrate (PC / PMMA film, PC film or flame-retardant substrate) and the infrared absorption layer was evaluated according to the evaluation method of ASTM D3359.

[0237] The evaluation was carried out in 6 grades from 5B to 0B. 5B indicates the strongest adhesion.

[0238] <Haze (%) of the multi-layer body after weather resistance test> With the acrylic resin side of the multi-layer body as the irradiation surface, light irradiation was carried out under the following conditions.

[0239] Device: SUV-W161, manufactured by Iwasaki Electric Co., Ltd.

[0240] Light source: Metal halide lamp.

[0241] Test environment: 85 °C (black panel temperature), 50% relative humidity.

[0242] Illuminance: 100 mW / cm 2 (365 nm).

[0243] Irradiation period: 24 hours (continuous irradiation).

[0244] Irradiation time: 200 hours.

[0245] The haze of the multi-layer body after the above light irradiation was measured in the same manner as above.

[0246] A: The change in haze is 2 or less compared to before the test B: The change in haze is greater than 2 compared to before the test <FMVSS test> For the above-obtained multi-layer body, using the FMVSS No. 302 flammability test device, starting from the right end of the test piece (350 mm × 100 mm × 0.375 mm), it was brought into contact with a 38-mm-high combustion flame for 15 seconds, and the combustion speed within a 254-mm combustion distance between the marking lines was measured. The measurement was carried out without a heat-resistant metal support wire (wire) in the test fixture, and the evaluation was carried out as described below.

[0247] A: The test piece does not burn or self-extinguishes before reaching the A marking line B: Self-extinguishes within 51 mm from the A marking line (and within 60 seconds) of the combustion distance C: Although it burns before reaching the B marking line, the combustion speed is 102 mm / min or less D: Burns before reaching the B marking line, and the combustion speed is faster than 102 mm / min.

[0248] [Table 2-1] [Table 2-2] [Table 2-3] [Table 3] In the table above, CWO represents the amount of CWO in the CWO dispersion (YMF-02A).

[0249] In the table above, Pigment Red 254 series pigments and FeOOH series pigments represent the amount of solid components.

[0250] In the table above, the application of HC to the opposite side indicates whether the surface of the acrylic resin layer has a hard coating, and a and b represent the composition of the resin composition for the hard coating.

[0251] As the results above show, the infrared absorbing layer of the multilayer structure of the present invention has high adhesion to the substrate, excellent weather resistance, and low haze. Moreover, it also has excellent infrared shielding performance.

[0252] In contrast, when the content of the component derived from the difunctional (meth)acrylate monomer (A) in the acrylic resin layer is higher (Comparative Examples 1 and 2), the haze is higher.

[0253] When the acrylic resin layer does not contain any component derived from the difunctional (meth)acrylate monomer (A) or contains it but in small amounts (Comparative Examples 3 and 7), the adhesion is poor.

[0254] Furthermore, when the (meth)acrylate monomer contained in the acrylic resin layer is a monofunctional or polyfunctional monomer (Comparative Examples 4 and 5), the adhesion is often poor and the infrared absorption performance is also poor.

[0255] When the infrared absorption layer is disposed on the polycarbonate resin layer side (Comparative Example 6), the infrared absorption performance is often poor.

[0256] When the substrate is a single-layer polycarbonate resin film (Comparative Example 8), the weather resistance is poor.

[0257] Symbol Explanation 1: Multi-layered body 2: Acrylic resin layer 3: Polycarbonate resin layer 4: Infrared absorption layer.

Claims

1. A multilayer comprising an acrylic resin layer, a polycarbonate resin layer, and an infrared absorbing layer, wherein the multilayer is characterized in that: The infrared absorption layer comprises an ultraviolet-curable resin, a photopolymerization initiator, and a colorant. The UV-curable resin contains a component derived from a bifunctional (meth)acrylate monomer (A-1) having an alicyclic and / or aromatic ring, and the proportion of the component derived from the monomer (A-1) in the infrared absorption layer is 10-31% by mass. The colorant includes tungsten oxide. The infrared absorbing layer is located on the side of the polycarbonate resin layer opposite to the acrylic resin layer.

2. The multilayer body according to claim 1, characterized in that: The monomer (A-1) includes the monomer represented by formula (1-1) and / or the monomer represented by formula (1-2). In equations (1-1) and (1-2), n and m are independent numbers that satisfy the condition that n+m is greater than 3 and less than 5.

3. The multilayer body according to claim 1 or 2, characterized in that: The haze value of the multilayer body is below 2%.

4. The multilayer body according to any one of claims 1 to 3, characterized in that: The proportion of tungsten oxide in the infrared absorption layer is above 20% by mass.

5. The multilayer body according to any one of claims 1 to 4, characterized in that: The photopolymerization initiator includes a photopolymerization initiator having an acylphosphine oxide backbone and / or an α-hydroxyketone backbone.

6. The multilayer body according to any one of claims 1 to 5, characterized in that: The content of sulfonate metal salt in at least one of the acrylic resin layer and the polycarbonate resin layer is 0.01 to 0.80% by mass.

7. The multilayer body according to any one of claims 1 to 5, characterized in that: The content of sulfonate metal salt in the polycarbonate resin layer is 0.01 to 0.80% by mass.

8. The multilayer body according to any one of claims 1 to 7, characterized in that: The multilayer body also has a hard coating. The hard coating layer is stacked in the following order: infrared absorption layer, polycarbonate resin layer, acrylic resin layer, and hard coating layer.

9. The multilayer body according to claim 8, characterized in that: The hard coating contains inorganic particles.

10. The multilayer body according to any one of claims 1 to 9, characterized in that: The multilayer body also has an anti-reflective layer.

11. The multilayer body according to any one of claims 1 to 10, characterized in that: The multilayer body also has a polarizing layer.

12. A dust cover for a head-up display, characterized in that: The dust cover for the head-up display comprises a multilayer body according to any one of claims 1 to 11.

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