Polycarbonate resin laminate for heat bending, and method for manufacturing the same

Abstract

To provide a polycarbonate resin laminate with improved weather resistance.SOLUTION: A polycarbonate resin laminate for heat bending 10 includes a substrate layer 1 containing polycarbonate resin, and a hard coat layer 2, which are laminated one upon another. A weather-resistant layer 3 is interposed between the substrate layer 1 and the hard coat layer 2. The weather-resistant layer 3 contains polycarbonate resin and an ultraviolet absorber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a polycarbonate resin laminate for hot bending and a method for manufacturing a polycarbonate resin laminate for hot bending. More specifically, the present invention relates to a polycarbonate resin laminate for hot bending, a curved member, a method for manufacturing a polycarbonate resin laminate for hot bending, and a method for manufacturing a curved member. [Background technology]

[0002] Polycarbonate resin is known to have high transparency, abrasion resistance, heat resistance, etc. Therefore, molded articles obtained by heat bending a polycarbonate resin sheet are suitably used, for example, as various lenses for sunglasses and ski goggles, motorcycle windshields, and vehicle window materials.

[0003] For example, Patent Document 1 (WO 2021 / 070632) discloses a polycarbonate resin laminate in which a predetermined penetration layer and a hard coat layer containing an ultraviolet absorber are laminated in this order on at least one surface of a polycarbonate resin substrate layer in order to improve abrasion resistance, heat bending property, and adhesion after heat bending. It also discloses that the penetration layer contains both the components of the polycarbonate resin substrate layer and the hard coat layer, thereby improving the adhesion of each layer. It also discloses that a method for forming the penetration layer and the hard coat layer can be achieved by applying an inorganic fine particle dispersion for forming the hard coat layer to the surface of the polycarbonate resin substrate layer to form the penetration layer and the hard coat layer simultaneously. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 070632 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional polycarbonate resin laminates such as those disclosed in Patent Document 1 contain an ultraviolet absorber in the hard coat layer that forms the outer surface. However, due to the resin properties of polycarbonate resin laminates, they may be used for long periods of time or exposed to harsh environments such as strong winds and dust, which makes the hard coat layer prone to wear and damage. As a result, the ultraviolet absorption effect of the conventional technology is impaired, leaving room for improvement in terms of maintaining good weather resistance. [Means for solving the problem]

[0006] The present inventors have conducted research into improving the weather resistance of polycarbonate resins while maintaining their inherent properties, such as abrasion resistance, and have found that by providing a weather-resistant layer containing an ultraviolet absorber below the hard coat layer, the weather-resistant layer can protect the substrate layer from ultraviolet rays even if the hard coat layer is worn, and have completed the present invention.

[0007] According to the present invention, the following polycarbonate resin laminate and related techniques are provided.

[0008] [1] A substrate layer containing a polycarbonate resin; a hard coat layer; A polycarbonate resin laminate in which a weather-resistant layer is interposed between the substrate layer and the hard coat layer, The polycarbonate resin laminate for heat bending processability, wherein the weather-resistant layer contains a polycarbonate resin and an ultraviolet absorber. [2] The polycarbonate resin laminate for hot bending process according to [1], A polycarbonate resin laminate for use in hot bending, wherein the content of an ultraviolet absorber contained in the weather-resistant layer is 1% by mass or more and 10% by mass or less, based on the total amount of the weather-resistant layer. [3] A polycarbonate resin laminate for hot bending process according to [1] or [2], A polycarbonate resin laminate for hot bending processability, wherein the hard coat layer contains an ultraviolet absorber of a different type from the ultraviolet absorber contained in the weather-resistant layer. [4] A polycarbonate resin laminate for hot bending process according to any one of [1] to [3], A polycarbonate resin laminate for use in hot bending, wherein the content of an ultraviolet absorber contained in the base layer is 1% by mass or less with respect to the total amount of the base layer. [5] A polycarbonate resin laminate for hot bending process according to any one of [1] to [4], L of the polycarbonate resin laminate for heat bending processing * a * b * a in color system * Values are -6 to 1, b * A polycarbonate resin laminate for heat bending process, having a value of -8 to 2.5. [6] A polycarbonate resin laminate for hot bending process according to any one of [1] to [5], A polycarbonate resin laminate for use in hot bending, wherein the thickness (μm) of the weather-resistant layer is 0.06 to 3.5% of the total thickness (μm) of the polycarbonate resin laminate for use in hot bending. [7] A polycarbonate resin laminate for hot bending process according to any one of [1] to [6], A polycarbonate resin laminate for hot bending processability, wherein the weather-resistant layer has a thickness (μm) of 10 to 100 μm. [8] A polycarbonate resin laminate for hot bending process according to any one of [1] to [7], The polycarbonate resin laminate for heat bending processability, wherein the ultraviolet absorber contained in the weather-resistant layer is a triazine-based ultraviolet absorber. [9] A polycarbonate resin laminate for hot bending process according to any one of [1] to [8], The polycarbonate resin laminate for hot bending processability is obtained by laminating the base layer and the weather-resistant layer by co-extrusion molding.

[10] A polycarbonate resin laminate for hot bending process according to any one of [1] to [9], a transition layer between the hard coat layer and the weather resistant layer; A polycarbonate resin laminate for hot bending processability, wherein the transition layer contains at least a portion of the components of the hard coat layer and at least a portion of the components of the weather-resistant layer.

[11] A curved member obtained by heat-bending the polycarbonate resin laminate for heat bending process according to any one of [1] to

[10] .

[12] A method for producing a polycarbonate resin laminate for hot bending process, in which a substrate layer containing a polycarbonate resin, a weather-resistant layer, and a hard coat layer are laminated in this order, comprising: a step of co-extrusion molding a resin composition for a base layer and a resin composition for a weather-resistant layer to laminate the base layer and the weather-resistant layer; applying a resin composition for a hard coat layer to a surface of the laminated weather-resistant layer opposite to the substrate layer to form a hard coat layer on the substrate layer; Including, The method for producing a polycarbonate resin laminate for heat bending processability, wherein the weather-resistant layer contains a polycarbonate resin and an ultraviolet absorber.

[13] A method for producing a curved member, comprising a step of hot bending a polycarbonate resin laminate for hot bending process obtained by the method for producing a polycarbonate resin laminate for hot bending process according to

[12] to form a curved member. [Effects of the Invention]

[0009] According to the present invention, a polycarbonate resin laminate having improved weather resistance is provided. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view schematically showing a polycarbonate resin laminate 10 for hot bending process according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] In this specification, the expression "a to b" in the description of a numerical range means from a to b, unless otherwise specified. For example, "1 to 5 mass%" means "1 mass% to 5 mass%." Furthermore, the lower limit and upper limit of a numerical range can be arbitrarily combined with the lower limit and upper limit of another numerical range.

[0012] Unless otherwise specified, each of the components and materials exemplified in this specification may be used alone or in combination of two or more. In this specification, the thickness of each layer refers to the thickness of one layer.

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The drawings are for illustrative purposes only, and the shapes and dimensional ratios of the components in the drawings do not necessarily correspond to actual products.

[0014] <Polycarbonate resin laminate for heat bending> 1 is a cross-sectional view schematically showing a polycarbonate resin laminate 10 for use in hot bending according to this embodiment. The polycarbonate resin laminate 10 for use in hot bending is in the form of a plate, sheet, or film.

[0015] The polycarbonate resin laminate 10 for hot bending processing comprises a substrate layer 1 containing polycarbonate resin and a hard coat layer 2 laminated together, with a weather-resistant layer 3 interposed between the substrate layer 1 and the hard coat layer 2, and the weather-resistant layer 3 containing polycarbonate resin and an ultraviolet absorber. In other words, since the weather-resistant layer 3 interposed between the substrate layer 1 and the hard coat layer 2 contains an ultraviolet absorber, even if the hard coat layer 2 is worn or damaged, the weather-resistant layer 3 maintains weather resistance and can protect the substrate layer 1.

[0016] In this embodiment, the polycarbonate resin laminate 10 for hot bending has a weather-resistant layer 3 and a hard coat layer 2 on both sides of the base layer 1, with one side of the weather-resistant layer 3 in contact with the base layer 1 and the other side in contact with the hard coat layer 2. As a result, the base layer 1 is not exposed on the surface of the polycarbonate resin laminate 10 for hot bending, which prevents the base layer 1 from being hit by sand, dust, flying stones, rain, etc., and from being abraded by other members, etc.

[0017] Furthermore, in conventional techniques in which an ultraviolet absorber is incorporated into a substrate layer, the substrate layer is relatively thicker than other layers, such as the hard coat layer, resulting in a low concentration of ultraviolet absorber, which tends to cause the substrate layer to yellow due to ultraviolet rays. Furthermore, yellowing of the substrate layer also causes the entire laminate to yellow, which tends to degrade the appearance of the laminate. In contrast, the polycarbonate resin laminate 10 for hot bending process of the present embodiment contains an ultraviolet absorber in the weather-resistant layer 3, which is thinner than the substrate layer 1, and can therefore contain a high concentration of ultraviolet absorber. Therefore, the weather-resistant layer 3 can effectively absorb ultraviolet rays that reach the substrate layer 1, which facilitates improving the weather resistance of the polycarbonate resin laminate 10 for hot bending process. Furthermore, even if the weather-resistant layer 3 yellows due to ultraviolet rays, the thin thickness of the weather-resistant layer 3 minimizes the impact on the appearance of the polycarbonate resin laminate 10 for hot bending process, making it easier to maintain a good appearance.

[0018] Polycarbonate resin laminate for heat bending 10L * a * b * a in color system * The value is preferably from -6 to 1, more preferably from -5 to 0, and further preferably from -4.5 to -1. Polycarbonate resin laminate for heat bending 10L * a * b * b in color space * The value is preferably from -8 to 2.5, more preferably from -6.5 to 1.5, and further preferably from -3 to 1. L * a * b *a in color system * value and b * By setting the value within the above range, the polycarbonate resin laminate 10 for hot bending process can maintain a good balance between good appearance and transparency.

[0019] Polycarbonate resin laminate for heat bending 10L * a * b * a in color system * value and b * The value can be adjusted by selecting and combining the combination of materials for the substrate layer 1, hard coat layer 2, and weather-resistant layer 3 and known manufacturing methods.

[0020] The total thickness of the polycarbonate resin laminate 10 for hot bending processability is preferably 3 mm or more, more preferably 5 mm or more, and even more preferably 8 mm or more, which allows the strength to be improved while maintaining good thermoformability. On the other hand, the thickness of the polycarbonate resin laminate 10 for hot bending is preferably 15 mm or less, more preferably 12 mm or less, and even more preferably 10 mm or less, which allows for improved thermoformability while maintaining good strength.

[0021] The hot bending process is intended to soften the base material layer 1 by heating the polycarbonate resin laminate 10 for hot bending process and then bend it into a desired shape by applying pressure. Only a part of the polycarbonate resin laminate 10 for hot bending process may be heated and bent, or the entire polycarbonate resin laminate 10 may be heated and bent. The processing conditions are set appropriately.

[0022] The total light transmittance of the polycarbonate resin laminate 10 for hot bending process can be appropriately set depending on the application, but from the viewpoint of letting in light while suppressing excessive glare from direct sunlight, it is preferably 10% or more, more preferably 15% or more, and preferably 90% or less, more preferably 80% or less. The total light transmittance can be measured in accordance with JIS K7361-1.

[0023] The polycarbonate resin laminate 10 for hot bending preferably has a heat shrinkage rate measured in accordance with the method specified in JIS K 6735 of 5% or less, more preferably 3% or less. By setting the heat shrinkage rate to the above upper limit or less, even if the polycarbonate resin laminate 10 for hot bending has a molded portion that has been thermoformed into a curved shape, it is possible to reliably suppress or prevent delamination between the layers of the polycarbonate resin laminate 10 for hot bending in the molded portion. As a result, the polycarbonate resin laminate 10 for hot bending has excellent weather resistance. Furthermore, when the polycarbonate resin laminate 10 for hot bending is printed to form a printed surface, it is possible to reliably suppress or prevent misalignment of the printed surface. The heat shrinkage rate is intended to be the maximum value among the heat shrinkage rates measured along the surface direction of the polycarbonate resin laminate 10 for hot bending process.

[0024] Each layer will be described in detail below.

[0025] [Base material layer 1] The base layer 1 is a layer that forms the base of the polycarbonate resin laminate 10 for hot bending processability. The base layer 1 contributes to maintaining good transparency and mechanical strength of the polycarbonate resin laminate 10 for hot bending processability. In this embodiment, the weather-resistant layer 3 is provided so as to be in contact with both surfaces of the base layer 1. The weather-resistant layer 3 may cover the entire surface of the base layer 1, may cover a part of the surface, or may cover it discontinuously.

[0026] The base layer 1 preferably has optical transparency (visible light transparency). The base layer 1 may be colorless, or may be colored in red, blue, yellow, or the like with a colorant described below, as long as it maintains optical transparency.

[0027] The thickness of the base layer 1 is preferably 3 mm or more, more preferably 5 mm or more, and even more preferably 8 mm or more, which can improve strength while maintaining good thermoformability. On the other hand, the thickness of the base layer 1 is preferably 15 mm or less, more preferably 12 mm or less, and even more preferably 10 mm or less, which can improve thermoformability while maintaining good strength.

[0028] The thickness of the base layer 1 is preferably 93.00 to 99.99% of the total thickness of the polycarbonate resin laminate 10 for hot bending processability, and more preferably 95.00 to 99.90%.

[0029] (Resin composition for base layer) The substrate layer 1 is a resin layer containing a polycarbonate resin, and is formed using a resin composition for a substrate layer. Polycarbonate resin has excellent transparency and mechanical strength such as rigidity, and also has high heat resistance.

[0030] As the polycarbonate resin, various resins can be used, but among them, aromatic polycarbonate resins are preferred. The aromatic polycarbonate resin is synthesized, for example, by an interfacial polycondensation reaction between bisphenol and phosgene, or a transesterification reaction between bisphenol and diphenyl carbonate. A bisphenol-type polycarbonate resin having a skeleton derived from bisphenol is preferably used as the main material. By using such a bisphenol-type polycarbonate resin, the base layer 1 exhibits even greater strength.

[0031] The base layer 1 may contain various additives such as resins other than polycarbonate resin, ultraviolet absorbers, colorants, antioxidants, fillers, plasticizers, light stabilizers, heat ray absorbers, and flame retardants, as described below, as long as the transparency and mechanical strength of the polycarbonate resin laminate 10 for hot bending process is maintained. For example, when the base layer 1 is formed by extrusion molding, discoloration can be suppressed by selecting a heat-resistant additive, and the transparency of the polycarbonate resin laminate 10 for hot bending process can be maintained.

[0032] When the base layer 1 contains a resin other than the above-mentioned polycarbonate resin, the proportion of the resin other than the polycarbonate resin is preferably 1 mass % or less, more preferably 0.5 mass % or less, and even more preferably 0.1 mass % or less, relative to the total amount of resin in the base layer 1, and it is even more preferable that the base layer does not contain any resin other than the polycarbonate resin.

[0033] When the base layer 1 contains an ultraviolet absorber, the content of the ultraviolet absorber is preferably 1% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.1% by mass or less, and even more preferably no ultraviolet absorber is contained, relative to the total amount of the base layer 1. By setting the content of the ultraviolet absorber in the base layer 1 to the above upper limit or less, the transparency and functionality of the base layer 1 can be more easily maintained.

[0034] As the colorant, known dyes and pigments may be used. When the base layer 1 contains a colorant, the content of the colorant is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less, relative to the total amount of the base layer 1, and it is even more preferable that the base layer 1 does not contain a colorant.

[0035] Examples of the dye include acid dyes, direct dyes, reactive dyes, and basic dyes, and one or more selected from these may be used in combination.

[0036] The pigment is not particularly limited, but examples thereof include phthalocyanine pigments such as phthalocyanine green and phthalocyanine blue; azo pigments such as fast yellow, disazo yellow, condensed azo yellow, benzimidazolone yellow, dinitroaniline orange, benzimidazolone orange, toluidine red, permanent carmine, permanent red, naphthol red, condensed azo red, benzimidazolone carmine, and benzimidazolone brown; anthraquinone pigments such as anthrapyrimidine yellow and anthraquinonyl red; copper pigments such as copper fluoride, ... organic pigments such as azomethine pigments such as azomethine yellow, quinophthalone pigments such as quinophthalone yellow, isoindoline pigments such as isoindoline yellow, nitroso pigments such as nickel dioxime yellow, perinone pigments such as perinone orange, quinacridone pigments such as quinacridone magenta, quinacridone maroon, quinacridone scarlet, and quinacridone red, perylene pigments such as perylene red and perylene maroon, pyrrolopyrrole pigments such as diketopyrrolopyrrole red, and dioxazine pigments such as dioxazine violet; Carbon pigments such as bomb black, lamp black, furnace black, ivory black, graphite, and fullerene, chromate pigments such as yellow lead and molybdate orange, sulfide pigments such as cadmium yellow, cadmium lithopone yellow, cadmium orange, cadmium lithopone orange, vermilion, cadmium red, cadmium lithopone red, sulfide, ochre, titanium yellow, titanium barium nickel yellow, red iron oxide, red lead, umber, brown iron oxide, zinc iron chrome brown, chrome oxide, cobalt green, cobalt chrome green, titanium Examples of the pigment include oxide pigments such as cobalt green, cobalt blue, cerulean blue, cobalt aluminum chrome blue, iron black, manganese ferrite black, cobalt ferrite black, copper chrome black, and copper chrome manganese black; hydroxide pigments such as viridian; ferrocyanide pigments such as Prussian blue; silicate pigments such as ultramarine; phosphate pigments such as cobalt violet and mineral violet; and other inorganic pigments (for example, cadmium sulfide and cadmium selenide). These pigments can be used alone or in combination of two or more.

[0037] [Hard coat layer 2] The hard coat layer 2 is provided on the substrate layer 1 and has the function of protecting the substrate layer 1. In this embodiment, weather-resistant layers 3 are provided on the upper and lower surfaces of the substrate layer 1, and the hard coat layer 2 is provided on the surface of the weather-resistant layer 3 opposite to the substrate layer 1.

[0038] The thickness of the hard coat layer 2 is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more, which improves the strength as a protective layer and can suppress breakage and cracks. On the other hand, the thickness of the hard coat layer 2 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less, which makes it easier to maintain good thermal processability and light transmittance.

[0039] (Resin composition for hard coat layer) The hard coat layer 2 is formed using a resin composition for a hard coat layer. The resin composition for the hard coat layer preferably contains at least one of a silicon-modified (meth)acrylic resin and dispersible silica particles having a polymerizable group, and more preferably contains both in terms of improving abrasion resistance.

[0040] (Silicone-modified (meth)acrylic resin) Silicone-modified (meth)acrylic resin (siloxane-modified (meth)acrylate) is a polymer (prepolymer) having a main chain in which structural units derived from (meth)acrylic monomers having a (meth)acryloyl group are repeated, and a repeating body (side chain) in which structural units having a siloxane bond are repeated and linked to this main chain.

[0041] That is, it is a polymer (prepolymer) in which a (meth)acrylic compound as the main chain and a compound having a siloxane bond (-Si-O-Si-) as the side chain are linked together.

[0042] The silicon-modified (meth)acrylic resin, by virtue of having the aforementioned main chain, imparts excellent transparency to the hard coat layer 2, and by virtue of having a repeating unit in which the aforementioned structural unit having a siloxane bond is repeated, imparts excellent scratch resistance and weather resistance to the hard coat layer 2, i.e., can impart the hard coat layer 2 with the function as a protective layer.

[0043] Specific examples of the main chain of the silicon-modified (meth)acrylic resin include those composed of repeating structural units derived from a monomer having a (meth)acryloyl group of at least one of the following formulas (1) and (2), and examples of those having repeating structural units derived from both of these monomers include those having the chemical formula shown in the following formula (12).

[0044] [ka] (In formula (1), n represents an integer of 1 or greater; R1 independently represents a hydrocarbon group, an organic group, or a hydrogen atom; and R0 independently represents a hydrocarbon group or a hydrogen atom.)

[0045] [ka] (In formula (2), m represents an integer of 1 or greater; R2 independently represents a hydrocarbon group, an organic group, or a hydrogen atom; and R0 independently represents a hydrocarbon group or a hydrogen atom.)

[0046] [ka] (In formula (12), m and n are integers of 1 or greater; R1, R2, and R3 each independently represent a hydrocarbon group, an organic group, or a hydrogen atom; and R0 independently represent a hydrocarbon group or a hydrogen atom.)

[0047] Furthermore, at least one end of the main chain or side chain of such a structure is bonded to a repeating body (sub-chain) in which a structural unit having a siloxane bond is repeated.

[0048] Because siloxane bonds have a high bonding strength, when the silicon-modified (meth)acrylic resin has a repeating structure in which structural units having siloxane bonds are repeated, it is possible to obtain a hard coat layer 2 with better heat resistance and weather resistance. Furthermore, the high bonding strength of the siloxane bonds makes it possible to obtain a hard hard coat layer 2, which further increases the scratch resistance and abrasion resistance of the polycarbonate resin laminate 10 for hot bending process against impacts from sand, dust, flying stones, and the like. The effect of the siloxane bond can also be obtained by using silica particles, which will be described later, and can be made more pronounced by using a silicon-modified (meth)acrylic resin and dispersible silica particles in combination.

[0049] Specific examples of repeating units having siloxane bonds include those composed of repeating structural units having siloxane bonds of at least one of the following formulas (3) and (4):

[0050] [ka] (In formula (3), X1 represents a hydrocarbon group or a hydroxyl group.)

[0051] [ka] (In formula (4), X2 represents a hydrocarbon group or a hydroxyl group, and X3 represents a divalent group in which a hydrogen atom has been removed from a hydrocarbon group or a hydroxyl group.)

[0052] Specific examples of the repeating structure in which the structural unit having a siloxane bond is repeated include those having polyorganosiloxane and those having silsesquioxane. The structure of the silsesquioxane may be any structure, such as a random structure, a cage structure, or a ladder structure.

[0053] Examples of the hydrocarbon group include alkyl groups such as a methyl group, an ethyl group, a propyl group, and an isopropyl group; cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group; aryl groups such as a phenyl group, a naphthyl group, and a 2-methylphenyl group; aralkyl groups such as a benzyl group, a diphenylmethyl group, and a naphthylmethyl group; a phenyl group; and a biphenyl group.

[0054] In addition, it is preferable that an unsaturated double bond be introduced into the end or side chain of the repeating unit in which a structural unit having a siloxane bond is repeated. As a result, when a urethane (meth)acrylate described below is contained in the resin composition, the unsaturated double bond can bond with the (meth)acryloyl group of the urethane (meth)acrylate to form a network of the silicon-modified (meth)acrylic resin and the urethane (meth)acrylate. Therefore, the silicon-modified (meth)acrylic resin and the urethane (meth)acrylate are more uniformly dispersed in the hard coat layer 2, and as a result, the hard coat layer 2 can exhibit the above-mentioned properties more uniformly throughout its entirety.

[0055] The content of the silicon-modified (meth)acrylic resin in the resin composition for the hard coat layer is not particularly limited, but is preferably 10 parts by mass or more and 70 parts by mass or less, and more preferably 20 parts by mass or more and 50 parts by mass or less, per 100 parts by mass of the resin composition for the hard coat layer. By setting the content of the silicon-modified (meth)acrylic resin to be equal to or greater than the above-mentioned lower limit, the hardness of the hard coat layer 2 can be maintained well. On the other hand, by setting the content of the silicon-modified (meth)acrylic resin to be equal to or less than the above-mentioned upper limit, the flexibility of the hard coat layer 2 can be easily maintained.

[0056] Examples of the silicone-modified (meth)acrylic resin having the above-mentioned structure include compounds represented by the following formulas (5) and (6).

[0057] [ka] (In formula (5), Me represents a methyl group, and m, n, and p each represent an integer of 1 or more.)

[0058] [ka] (In formula (6), Me represents a methyl group, m, n, and p each represent an integer of 1 or more, and R1, R2, R3, and R4 each independently represent a hydrocarbon group, an organic group, or a hydrogen atom.)

[0059] (silica particles) The silica particles are dispersible silica particles having polymerizable groups.

[0060] The silica particles are preferably in the form of a solvent-dispersed sol. In the solvent dispersion sol of silica particles, the dispersion medium is preferably an organic solvent from the viewpoint of compatibility with other components and dispersibility. The organic solvent is not particularly limited, but examples thereof include ketone solvents, aromatic solvents, alcohol solvents, glycol solvents, glycol ether solvents, ester solvents, petroleum solvents, haloalkane solvents, amide solvents, etc. These may be used alone or in combination of two or more.

[0061] The silica particles may be those whose surfaces are modified with an organic group or those that are not surface-modified, but silica particles whose surfaces are modified with an organic group having an unsaturated group are preferred. That is, it is preferable to make silica particles in the form of a composite in which an organic group having an unsaturated group on the surface thereof is introduced physically or chemically (preferably chemically) onto the surface of the silica particles. The unsaturated group is preferably a radically polymerizable group, specifically a functional group having a carbon-carbon double bond (also called a polymerizable double bond), such as a vinyl group, a (meth)acryloyl group, a (meth)acrylamide group, a vinyl ether group, an allyl group, etc. Of these, a (meth)acryloyl group is preferred from the viewpoints of adhesion and scratch resistance.

[0062] The silica particles may have any shape, such as spherical, hollow, porous, rod-like, plate-like, fibrous, or irregular shape, but the preferred shape is spherical.

[0063] The upper and lower limits of the particle size of the silica particles are preferably 5 to 200 nm, more preferably 10 to 100 nm.

[0064] The content of the silica particles in the resin composition for a hard coat layer is not particularly limited, but is preferably 10 parts by mass or more and 70 parts by mass or less, and more preferably 20 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the resin composition for a hard coat layer. By setting the content of silica particles to the above lower limit or more, the hardness of the hard coat layer 2 can be maintained at a good level, and abrasion resistance can be obtained. On the other hand, by setting the content of silica particles to the above upper limit or less, the flexibility of the hard coat layer 2 can be easily maintained.

[0065] Furthermore, the resin composition for the hard coat layer may contain the following urethane (meth)acrylate, (meth)acrylate monomer, etc.

[0066] (urethane (meth)acrylate) Moreover, it is preferable that the resin composition for the hard coat layer further contains urethane (meth)acrylate.

[0067] When an unsaturated double bond is introduced into the end or side chain of a repeating unit having a siloxane bond in the silicon-modified (meth)acrylic resin or silica particles, the hard coat layer resin composition contains a urethane (meth)acrylate, and the (meth)acryloyl group of the urethane (meth)acrylate bonds with the unsaturated double bond, forming a network between the silicon-modified (meth)acrylic resin or silica particles and the urethane (meth)acrylate. As a result, the hard coat layer resin composition is cured to obtain a cured product, and a hard coat layer 2 composed of this cured product is formed. Note that the hard coat layer resin composition is cured by bonding the (meth)acryloyl group with the unsaturated double bond through photocuring, in which the hard coat layer resin composition is cured by irradiating it with energy rays such as ultraviolet light.

[0068] By containing urethane (meth)acrylate in the hard coat layer 2 formed as described above, the flexibility of the hard coat layer 2 can be improved, and since the polycarbonate resin laminate 10 for heat bending is applied to a part or all of the polycarbonate resin laminate 10 for heat bending processing having a curved shape, the occurrence of cracks on the surface of the hard coat layer 2 can be appropriately suppressed when the polycarbonate resin laminate 10 for heat bending processing is heat bent, and therefore, excellent thermoformability can be imparted to the polycarbonate resin laminate 10 for heat bending processing.

[0069] Furthermore, by combining the above-mentioned silicon-modified (meth)acrylic resin with this urethane (meth)acrylate, it is possible to obtain a polycarbonate resin laminate 10 for hot bending that has both excellent scratch resistance and thermoformability at a high level. Also, due to the improved scratch resistance, the use of the polycarbonate resin laminate 10 for hot bending can effectively prevent scratches on the surface of the hard coat layer 2, even if sand, dust, flying stones, etc. collide with the hard coat layer 2 after irradiation with ultraviolet rays contained in sunlight.

[0070] The urethane (meth)acrylate is a compound having a main chain with a urethane bond (-OCONH-) and a (meth)acryloyl group linked to the main chain. The urethane (meth)acrylate is a monomer or oligomer.

[0071] The urethane (meth)acrylate having such a structure is a compound with excellent flexibility due to the presence of urethane bonds. Therefore, by including urethane (meth)acrylate in the hard coat layer 2, it is possible to impart further flexibility (softness) to the hard coat layer 2. Therefore, when the polycarbonate resin laminate 10 for hot bending processability is molded into a curved shape, it is possible to reliably suppress the occurrence of cracks in the bent portion.

[0072] The urethane (meth)acrylate can be obtained, for example, as a reaction product between an isocyanate compound obtained by reacting a polyol with a diisocyanate, and a (meth)acrylate monomer having a hydroxyl group.

[0073] Examples of the polyol include polyether polyol, polyester polyol, and polycarbonate diol.

[0074] Polyester polyols can be obtained, for example, by polycondensation of a diol with a dicarboxylic acid or dicarboxylic acid chloride, or by esterifying a diol or dicarboxylic acid and then transesterifying it. Examples of dicarboxylic acids include adipic acid, succinic acid, glutaric acid, pimelic acid, sebacic acid, azelaic acid, maleic acid, terephthalic acid, isophthalic acid, and phthalic acid. Examples of diols include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, tripropylene glycol, and tetrapropylene glycol.

[0075] Furthermore, examples of polycarbonate diols that can be used include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 2-ethyl-1,3-hexanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanediol, and polyoxyethylene glycol, and these can be used alone or in combination of two or more.

[0076] Examples of (meth)acrylate monomers having a hydroxyl group include trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol triacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, and polyethylene glycol monoacrylate.

[0077] The content of urethane (meth)acrylate in the resin composition for the hard coat layer is not particularly limited, but is preferably 10 to 75 parts by mass, and more preferably 15 to 65 parts by mass, per 100 parts by mass of the resin composition for the hard coat layer. If the content of urethane (meth)acrylate in the resin composition for the hard coat layer is less than the lower limit, the flexibility of the hard coat layer 2 may be poor, depending on the type of urethane (meth)acrylate. If the content of urethane (meth)acrylate in the resin composition for the hard coat layer exceeds the upper limit, the content of materials other than urethane (meth)acrylate in the resin composition for the hard coat layer may be relatively reduced, depending on the type of urethane (meth)acrylate, and the scratch resistance of the polycarbonate resin laminate 10 for hot bending processability may be reduced.

[0078] ((Meth)acrylate Monomer) Moreover, the resin composition for the hard coat layer preferably further contains a (meth)acrylate monomer.

[0079] When an unsaturated double bond is introduced into the end or side chain of a repeating unit of a siloxane bond-containing structural unit contained in a silicon-modified (meth)acrylic resin, the resin composition for a hard coat layer contains a (meth)acrylate monomer, and the (meth)acryloyl group of the (meth)acrylate monomer bonds with the unsaturated double bond, forming a network of the silicon-modified (meth)acrylic resin and the (meth)acrylate monomer, and as a result, the resin composition for a hard coat layer hardens to form a hard coat layer 2.

[0080] The (meth)acrylate monomer is not particularly limited, but examples thereof include pentaerythritol tetraacrylate, ditrimethylolpropane triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, ethoxylated pentaerythritol triacrylate, ethoxylated pentaerythritol tetraacrylate, polyethylene glycol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated hydrogenated bisphenol A diacrylate, ethoxylated cyclohexane dimethanol diacrylate, tricyclodecane dimethanol diacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, and isobornyl acrylate. One or more of these may be used in combination. Among these, aromatic-free resins are preferred from the viewpoint of improving the weather resistance of the polycarbonate resin laminate 10 for hot bending processability.

[0081] The content of the (meth)acrylate monomer in the resin composition for the hard coat layer is not particularly limited, but is preferably 5 parts by mass or more and 55 parts by mass or less, and more preferably 10 parts by mass or more and 30 parts by mass or less, per 100 parts by mass of the resin composition for the hard coat layer.

[0082] (Isocyanate) Preferably, the resin composition for a hard coat layer further contains an isocyanate, which has an isocyanurate skeleton and has di- or tri-functional isocyanate groups.

[0083] As a result, in the resin composition for hard coat layer, isocyanate functions as a cross-linking agent that bonds (cross-links) between molecules of the silicon-modified (meth)acrylic resin. That is, by including isocyanate as a cross-linking agent, the hydroxyl groups in the main chain of the silicon-modified (meth)acrylic resin, which is made up of repeated structural units derived from a (meth)acrylic monomer having a (meth)acryloyl group, react with the isocyanate groups of the isocyanate to form a cross-linked structure composed of urethane bonds, resulting in the formation of a hard coat layer 2 composed of a cured product of the resin composition for hard coat layer. Note that the curing of the resin composition for hard coat layer by bonding these hydroxyl groups with the isocyanate groups is carried out by thermal curing, in which the resin composition for hard coat layer is cured by heating.

[0084] In the hard coat layer 2 formed as described above, a network can be constructed by bonding hydroxyl groups and isocyanate groups, so that the scratch resistance and weather resistance of the hard coat layer 2 can be further improved.

[0085] The content of isocyanate in the resin composition for hard coat layer is not particularly limited, but is preferably 3 parts by mass or more and 40 parts by mass or less, and more preferably 10 parts by mass or more and 25 parts by mass or less, relative to 100 parts by mass of the resin composition for hard coat layer.

[0086] (Other ingredients) The resin composition for the hard coat layer may contain other materials in addition to the various materials described above, such as a resin material other than the silicon-modified (meth)acrylic resin, a photopolymerization initiator, an ultraviolet absorber (described later), a colorant, a sensitizer, a stabilizer, a surfactant, an antioxidant, an anti-reducing agent, an antistatic agent, a surface conditioner, a hydrophilic additive, a filler, and a solvent, and one or more of these may be used in combination.

[0087] When the hard coat layer 2 contains an ultraviolet absorber, it is preferable that the ultraviolet absorber is of a different type from the ultraviolet absorber contained in the weather-resistant layer 3 described below. For example, the UV absorbers may be selected depending on the manufacturing methods of the hard coat layer 2 and the weather-resistant layer 3. For example, when the weather-resistant layer 3 is extrusion-molded, a UV absorber with relatively high heat resistance may be selected. When the hard coat layer 2 is formed by coating, a UV absorber with relatively high dispersibility and little bleeding during the coating film formation process may be selected. Specifically, for example, it is preferable that the hard coat layer 2 contains a triazine-based compound with a reactive functional group (e.g., "RUVA-93" manufactured by Otsuka Chemical Co., Ltd. or "Tinuvin 400" manufactured by BASF Japan Ltd.) and the weather-resistant layer 3 contains a triazine-based compound with excellent heat resistance that can function even after the extrusion process (e.g., "Tinuvin 1577" manufactured by BASF Japan Ltd.). This allows the hard coat layer 2 and the weather-resistant layer 3 to be appropriately formed, resulting in increased adhesion between them and improved mechanical strength of the polycarbonate resin laminate 10 for hot bending processability, which in turn facilitates further improvement in weather resistance. Furthermore, using UV absorbers with different absorption wavelength ranges broadens the absorption wavelength range, making it easier to achieve stable weather resistance.

[0088] The content of the ultraviolet absorber in the hard coat layer 2 is preferably 1 mass % or more and 6 mass % or less, more preferably 2 mass % or more and 5.5 mass % or less, and even more preferably 3 mass % or more and 6 mass % or less, relative to the total amount of the hard coat layer 2. By setting the content of the ultraviolet absorber in the hard coat layer 2 to the above lower limit or more, better weather resistance can be obtained. On the other hand, by setting the content of the ultraviolet absorber in the hard coat layer 2 to the above upper limit or less, it becomes easier to obtain good transparency and heat bending processability while maintaining weather resistance.

[0089] [Weatherproof layer 3] The weather-resistant layer 3 is interposed between the substrate layer 1 and the hard coat layer 2, and has the function of protecting the substrate layer 1 from ultraviolet rays. In the polycarbonate resin laminate 10 for hot bending processability, the weather-resistant layers 3 are provided on the upper and lower surfaces of the base layer 1, respectively.

[0090] The weather-resistant layer 3 preferably has light transparency (visible light transparency).

[0091] The thickness of the weather-resistant layer 3 is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more, which improves the strength of the protective layer and makes it possible to suppress breakage and cracks. On the other hand, the thickness of the weather-resistant layer 3 is preferably 100 μm or less, more preferably 90 μm or less, and even more preferably 80 μm or less, which makes it easier to maintain good thermal processability and light transmittance.

[0092] The thickness of the weather-resistant layer 3 is preferably 0.06 to 3.5%, more preferably 0.08 to 2.0%, and even more preferably 0.1 to 1.5%, of the total thickness of the polycarbonate resin laminate for hot bending 10. By keeping the thickness within this range, good hot bending processability can be obtained while improving weather resistance.

[0093] (Resin composition for weather-resistant layer) The weather-resistant layer 3 is a resin layer containing an ultraviolet absorber. Resin materials include, but are not limited to, acrylic resins, polycarbonates, polystyrenes, epoxy resins, cyclic ether resins such as oxetane resins, polyamides, polyimides, polybenzoxazoles, polysilanes, polysilazanes, silicone resins, fluororesins, polyurethanes, polyolefins, polybutadiene, polyisoprene, polychloroprene, polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyethylene succinate, polysulfones, polyethers, and cyclic olefin resins such as benzocyclobutene resins and norbornene resins. One or more of these may be used in combination (as a polymer alloy, polymer blend (mixture), copolymer, etc.). Among these, polycarbonates or polyamides are preferred, and polycarbonates are more preferred. The use of polycarbonates can improve the strength and transparency of the polycarbonate resin laminate 10 for hot bending processability.

[0094] The content of the ultraviolet absorber in the weather-resistant layer 3 is preferably 1 mass % or more and 10 mass % or less, more preferably 2 mass % or more and 8 mass % or less, and even more preferably 3 mass % or more and 6 mass % or less, relative to the total amount of the weather-resistant layer 3. By setting the content of the ultraviolet absorber in the weather-resistant layer 3 to the above lower limit or more, better weather resistance can be obtained. On the other hand, by setting the content of the ultraviolet absorber in the weather-resistant layer 3 to the above upper limit or less, it becomes easier to obtain good transparency and hot bending processability while maintaining weather resistance.

[0095] (ultraviolet absorber) The ultraviolet absorber is not particularly limited, but examples thereof include compounds that absorb light with wavelengths of 100 nm or more and 400 nm or less, which can suppress the transmission of ultraviolet light and visible light with relatively short wavelengths (light with wavelengths of 400 nm or less), thereby improving weather resistance.

[0096] The ultraviolet absorber is not particularly limited, but examples thereof include triazine-based, benzophenone-based, benzotriazole-based, and cyanoacrylate-based compounds, and one or two of these may be used in combination. Among these, triazine-based compounds are preferred.

[0097] Examples of triazine compounds include 2-mono(hydroxyphenyl)-1,3,5-triazine compounds, 2,4-bis(hydroxyphenyl)-1,3,5-triazine compounds, and 2,4,6-tris(hydroxyphenyl)-1,3,5-triazine compounds. Specific examples 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, and 2,4-diphenyl-(2-hydroxy-4-propoxyphenyl)-1,3,5-triazine. )-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, 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-dodecyloxyphenyl)-1,3,5-triazine, 2,4- Diphenyl-6-(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-butoxyethoxy)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3-5-triazine, 2,4,6-tris(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-ethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine -propoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-dodecyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine, 2,4,6-Tris(2-hydroxy-4-ethoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-butoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-propoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-methoxycarbonylpropyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-ethoxycarbonylethyloxyphenyl)-1,3,5-triazine, 2,4,6- Tris(2-hydroxy-4-(1-(2-ethoxyhexyloxy)-1-oxopropan-2-yloxy)phenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-methoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-ethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-propoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-butoxyphenyl) -1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-hexyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-octyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-dodecyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-benzyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-ethoxyphenyl)-1,3,5-triazine 2,4,6-tris(2-hydroxy-3-methyl-4-butoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-propoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-methoxycarbonylpropyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-ethoxycarbonylethyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-(1-(2-ethoxyhexyloxy)-1-oxopropan-2-yloxy)phenyl)-1,3,5-triazine, etc. Commercially available triazine-based ultraviolet absorbers include, for example, "Tinuvin 1577," "Tinuvin 400," and "Tinuvin 405" (manufactured by BASF Japan Ltd.), and "RUVA-93" (manufactured by Otsuka Chemical Co., Ltd.), and one or more of these may be used in combination.

[0098] Among these, the ultraviolet absorber contained in the weather-resistant layer 3 is preferably a triazine-based compound.

[0099] [Transition Layer] A transition layer (not shown) may be present between the hard coat layer 2 and the weather resistant layer 3 . The transition layer contains at least some of the components of the hard coat layer 2 and at least some of the components of the weather-resistant layer 3. This increases the adhesion between the hard coat layer 2 and the weather-resistant layer 3, and improves the heat bending processability of the polycarbonate resin laminate 10 for heat bending processability.

[0100] The thickness of the transition layer is preferably 2 to 9 μm, and more preferably 3 to 5 μm.

[0101] The transition layer can be confirmed by observation with a scanning electron microscope (SEM). That is, another layer (transition layer) with different brightness can be confirmed between the hard coat layer 2 and the weather-resistant layer 3.

[0102] (Transition layer manufacturing method) The transfer layer can be formed by applying a resin composition for a hard coat layer onto the weather-resistant layer 3 to form the hard coat layer 2. That is, by forming the weather-resistant layer 3 and then applying the resin composition for a hard coat layer to form the hard coat layer 2, the solvent contained in the resin composition for a hard coat layer can cause a portion of the surface of the weather-resistant layer 3 to transfer to the subsequent hard coat layer 2. This improves the adhesion between the hard coat layer 2 and the weather-resistant layer 3 and improves thermal processability, such as bending.

[0103] [others] The polycarbonate resin laminate 10 for use in hot bending may further have other layers laminated on the hard coat layer 2 as needed. Examples of other layers include decorative layers. This can enhance the design of the polycarbonate resin laminate 10 for use in hot bending. In the polycarbonate resin laminate 10 for hot bending processability, it is preferable not to provide an adhesive layer between the substrate layer 1, the weather-resistant layer 3 and the hard coat layer 2 in order to obtain good hot bending processability and transparency.

[0104] [Application] The polycarbonate resin laminate 10 for heat bending process can also be used by being attached to curved window members found in vehicles such as automobiles, motorcycles, and trains, as well as in aircraft, ships, houses, etc. This window member can be applied to window members provided in vehicles and the like that are positioned between a person and an object that the person can see, as well as window members that are positioned between various devices such as sensors and display devices provided in vehicles and the object.

[0105] <Method for manufacturing polycarbonate resin laminate 10 for heat bending processing> The method for producing the polycarbonate resin laminate 10 for hot bending process includes the following steps. (Step 1) A step of laminating the base layer 1 and the weather-resistant layer 3 by co-extrusion molding a resin composition for the base layer and a resin composition for the weather-resistant layer. (Step 2) A step of applying a resin composition for a hard coat layer to the surface of the laminated weather-resistant layer 3 opposite to the substrate layer 1 to form a hard coat layer 2 on the substrate layer 1. Each step will be described in detail below.

[0106] (Process 1) First, a resin composition for the base layer and a resin composition for the weather-resistant layer are prepared. The resin composition for the base layer can be prepared, for example, by premixing a polycarbonate resin raw material and any additives using a mixer, followed by extrusion melt kneading, and then granulating and pelletizing using a granulator. Similarly, the resin composition for the weather-resistant layer may be prepared by premixing the constituent resin raw materials and any additives using a mixer, followed by extrusion melt kneading, and then granulating and pelletizing using a granulator. Next, the pelletized materials are co-extruded in a known extruder to form sheets and laminate them together, thereby laminating the base material layer 1 and the weather-resistant layer 3 together. Furthermore, when laminating by co-extrusion without going through such pelletization, it is also possible to directly melt-knead the materials in an extruder and extrude them through a die to form a sheet, which can then be laminated.

[0107] In the coextrusion method, each resin is melt-extruded using a separate extruder, and the resins are laminated into a sheet using a feed block or multi-manifold die. The laminated sheet may be cooled before being wound onto a roll.

[0108] (Process 2) Next, a resin composition for a hard coat layer is applied to the surface of the laminated weather-resistant layer 3 opposite to the substrate layer 1. The application method is not particularly limited, and examples thereof include known and commonly used coating methods such as brush coating, roller coating, spray coating, dip coating, flow coater coating, roll coater coating, and electrodeposition coating. The resin composition for the hard coat layer is prepared as a varnish-like liquid material containing a solvent. After the varnish-like resin composition for the hard coat layer is applied to the weather-resistant layer 3, the solvent is dried and the composition is cured, thereby forming the hard coat layer 2 on the weather-resistant layer 3. Specifically, when the resin composition for the hard coat layer contains an ultraviolet absorber, the liquid coating of the resin composition for the hard coat layer can be cured by irradiating it with ultraviolet light at a high exposure dose (for example, 1000 mJ to 2000 mJ).

[0109] By going through the above steps, the polycarbonate resin laminate 10 for hot bending process can be manufactured.

[0110] <Curved member> The curved member of this embodiment is obtained by bending the polycarbonate resin laminate 10 for heat bending process by heat bending. The conditions for the hot bending process are set as appropriate, but examples include a method of hot bending by partial heating using a pipe heater, a non-contact double-sided heating sandwich heater, a far-infrared heater, etc., or by total heating using an electric furnace.

[0111] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations can also be adopted. [Example]

[0112] Next, the present invention will be described in detail with reference to examples, but the content of the present invention is not limited to the examples.

[0113] 1. Raw material preparation First, the raw materials used in the production of the polycarbonate resin laminate for hot bending process are shown below.

[0114] [Materials for base layer and weather-resistant layer] Polycarbonate resin 1: Bisphenol A polycarbonate (manufactured by Mitsubishi Engineering Plastics Corporation, "E2000FN") was prepared. Additive 1: Additive 1 was prepared by blending 99.7% by mass of polycarbonate resin, 0.1% by mass of carbon black, 0.1% by mass of 1,4-bis[(2,6-diethyl-4-methylphenyl)amino]-9,10-anthraquinone, 0.05% by mass of 3-methyl-6-[(4-methylphenyl)amino]-3H-dibenzo[f,ij]isoquinoline-2,7-dione, and 0.05% by mass of 1-phenylthioanthraquinone. Ultraviolet absorber 1: A hydroxyphenyltriazine-based ultraviolet absorber (manufactured by BASF Japan, "Tinuvin 1577 ED") was prepared.

[0115] [Hard coat layer materials] Silicone-modified (meth)acrylic resin 1: Siloxane-modified acrylate (manufactured by DIC Corporation, "MFG Coat SD-101") was prepared. Silica particles 1: "BYK-UV3518" manufactured by BYK Japan was prepared. Urethane (meth)acrylate 1: 7. Octafunctional urethane acrylate (manufactured by Mitsubishi Chemical Corporation, "UV-1700B") was prepared. Urethane (meth)acrylate 2: A bifunctional urethane acrylate (UV-3310B, manufactured by Mitsubishi Chemical Corporation) was prepared. (Meth)acrylate monomer 1: A bifunctional acrylate monomer (manufactured by Shin-Nakamura Chemical Co., Ltd., "A-BPE-4") was prepared. Polymerization initiator 1: A photopolymerization initiator (manufactured by IGM Resins) was prepared. Ultraviolet absorber 2: A hydroxyphenylbenzotriazole-based ultraviolet absorber having a (meth)acryloyl group (manufactured by Otsuka Chemical Co., Ltd., "RUVA-93") was prepared. UV absorber 3: A hydroxyphenyltriazine UV absorber (manufactured by BASF Japan, "Tinuvin 479") was prepared.

[0116] 2. Preparation of Resin Composition for Hard Coat Layer A mixture of 60.0 mass% urethane (meth)acrylate 1, 10.0 mass% urethane (meth)acrylate 2, 20.0 mass% (meth)acrylate monomer 1, 5.0 mass% polymerization initiator 1, 2.5 mass% UV absorber 2, and 2.5 mass% UV absorber 3 was diluted with propylene glycol monomethyl ether (PM) as a solvent and then stirred to prepare coating material composition 1.

[0117] 3. Formation of polycarbonate resin laminate (sheet) for heat bending processing Example 1 A laminate consisting of the base layer and the weather-resistant layer was formed by co-extrusion of a resin composition for the base layer consisting of 99.75% by mass of polycarbonate resin 1 and 0.25% of additive 1, and a resin composition for the weather-resistant layer consisting of 95% by mass of polycarbonate resin 1 and 5% by mass of UV absorber 1. The laminate had a combined thickness of 8 mm for the base layer and the weather-resistant layer, and the weather-resistant layer was 50 μm thick.

[0118] The above-mentioned coating material composition 1 was used as a resin composition for a hard coat layer, and the resin composition for a hard coat layer was applied to the weather-resistant layer side of the obtained laminate, dried at 80°C, and UV-cured to form a hard coat layer with a thickness of 8 μm, thereby obtaining a polycarbonate resin laminate sheet for hot bending process. The UV curing conditions were as follows: an electrodeless UV lamp manufactured by FUSION Systems, irradiation distance 50 mm, conveyor speed 1.5 m / min, irradiation intensity 500 mW / cm 2 , cumulative light intensity 1700mJ / cm 2 UV light was irradiated under the following conditions.

[0119] <Examples 2 to 6> A polycarbonate resin laminate sheet for hot bending processing was obtained in the same manner as in Example 1, except that 1 part of the coating material composition, 1 part of the silicon-modified (meth)acrylic resin, and 1 part of the silica particles were mixed in the proportions (parts by mass) shown in Table 1 to prepare a resin composition for the hard coating layer.

[0120] <Comparative Example 1> A laminate comprising a substrate layer and a weather-resistant layer was formed by co-extrusion of a resin composition for a substrate layer consisting of 99.75% by mass of polycarbonate resin 1 and 0.25% of additive 1, and a resin composition for a weather-resistant layer consisting of 95% by mass of polycarbonate resin 1 and 5% by mass of UV absorber 1, in the same manner as in Example 1. A hard coat layer was not provided, and the resulting laminate was used as a polycarbonate resin laminate sheet for hot bending process.

[0121] <Comparative Examples 2 to 6> A resin composition for the base layer, which was composed of 99.75% by mass of polycarbonate resin 1 for the base layer and 0.25% of additive 1, was extrusion molded to obtain a base sheet. A resin composition for a hard coat layer was prepared in the same manner as in Example 1, except that the mixing ratio of coating material composition 1, silicon-modified (meth)acrylic resin 1, and silica particles 1 was as shown in Table 1. The obtained resin composition for a hard coat layer was applied to the surface of a substrate sheet, and a hard coat layer was formed in the same manner as in Example 1. This was used as a polycarbonate resin laminate sheet for hot bending process.

[0122] 4. Evaluation The resulting laminate was subjected to the following measurements and evaluations, and the results are shown in Tables 1 and 2.

[0123] Observation of the transition layer For each laminate, the presence of a transition layer between the weather-resistant layer and the hard coat layer was confirmed by SEM observation, and the thickness (μm) of the transition layer was measured.

[0124] L * a * b * a in color system * value and b * value The appearance of each laminate was measured using a tristimulus value direct reading colorimeter (manufactured by Suga Test Instruments, "Color Cute i") under a D65 light source with a 10° field of view and a transmission method. * value, b * The values were measured.

[0125] ·Total transmittance (%) For each laminate, the total light transmittance (%) was determined using a haze meter (trade name: NDH2000, manufactured by Nippon Denshoku Kogyo Co., Ltd.) in accordance with JIS K7361-1 (1997).

[0126] Heat shrinkage rate (%) Using each laminate, a test piece (width 150 mm, length 150 mm, thickness 8 mm) was prepared. A circle with a diameter of 100 mm was drawn on the test piece with a compass, which was then heated and dried for 24 hours in a hot air circulating oven set at 90°C, and cooled in a desiccator to 23°C. The diameter L0 of the test piece was measured in both the machine direction (the co-extrusion direction of the laminate; MD) and the direction perpendicular to the machine direction (TD). The test piece was then heated for 75 minutes in a hot air circulating oven set at 190°C, cooled in a desiccator to 23°C, and the diameter L1 was measured at the same location as the diameter of the circle measured earlier. The obtained value was applied to the following formula (A) to calculate the heat shrinkage rate (%). Heat shrinkage rate (%) = {(L0 - L1) / L0} x 100 (A)

[0127] ·Weather resistance Each laminate was subjected to an accelerated test using a carbon arc sunshine weatherometer in accordance with JIS K 5600, and the yellowing index (ΔYI) after 1000 hours was measured. The appearance (color) was observed and evaluated according to the following criteria. ·standard ⊚: ΔYI was less than 0.6 and there was no change in appearance (color). ◯: ΔYI was less than 1.0 and there was no change in appearance (color). △: ΔYI was 1.0 or more and less than 2.0, and a slight change in appearance (color) was observed. ×: ΔYI was 2.0 or more and a change in appearance (color) was observed.

[0128] -Heat bending workability Using each laminate, prepare a test piece (width 60 mm, length 120 mm).Next, the test piece is heated in a hot air circulation oven set at 170 ° C for 10 minutes to soften, and then immediately after removing from the oven, the test piece is placed along the longitudinal direction of a wooden cylinder via a flannel cloth, with the hard coat layer side of the test piece facing outward, and the test piece is kept in this state until the temperature of the test piece is cooled to around room temperature, and the test piece is formed into a single curved surface.Then, the appearance of the test piece is observed and evaluated according to the following criteria. The wooden cylinders were prepared with radii of 150 mm and 200 mm, and each was subjected to single-curve molding. ·standard ⊚: Thermoforming was possible using both 150mm and 200mm radius wooden molds, and no cracks, paint peeling, or changes in appearance occurred. Good: When using a wooden mold with a radius of 150 mm, cracks, paint peeling, and changes in appearance were observed due to thermoforming, but thermoforming was possible with a wooden mold with a radius of 200 mm, and no cracks, paint peeling, or changes in appearance occurred. ×: In both the 150 mm radius and 200 mm radius wooden molds, cracks, peeling of the coating film, and changes in appearance such as cloudiness and roughness of the surface occurred due to thermoforming.

[0129] Abrasion resistance The surface of each laminate was subjected to a Taber abrasion test in accordance with ASTM D1044 using an abrasion wheel (product name: CS-10F, manufactured by Taber) under conditions of a load of 500 g and 500 revolutions. The haze value of the surface of each laminate was measured before and after the Taber abrasion test, and the change in haze value (ΔH; %) was calculated and evaluated according to the following criteria. The haze value was measured using a haze meter (product name: NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.). ·standard ◎: ΔH was less than 5%, and the abrasion resistance was excellent. ◯: ΔH was 5% or more and less than 10%, and the abrasion resistance was good. ×: ΔH was 10% or more, and the abrasion resistance was not good.

[0130] [Table 1]

[0131] [Table 2] [Explanation of symbols]

[0132] 10 Polycarbonate resin laminate for heat bending 1 Base material layer 2 Hard coat layer 3 Weatherproof layer

Claims

1. a substrate layer containing a polycarbonate resin; a hard coat layer; A polycarbonate resin laminate in which a weather-resistant layer is interposed between the substrate layer and the hard coat layer, The polycarbonate resin laminate for heat bending processability, wherein the weather-resistant layer contains a polycarbonate resin and an ultraviolet absorber.

2. The polycarbonate resin laminate for hot bending process according to claim 1, A polycarbonate resin laminate for hot bending processability, wherein the content of an ultraviolet absorber contained in the weather-resistant layer is 1% by mass or more and 10% by mass or less, based on the total amount of the weather-resistant layer.

3. The polycarbonate resin laminate for hot bending process according to claim 1 or 2, A polycarbonate resin laminate for hot bending processability, wherein the hard coat layer contains an ultraviolet absorber of a different type from the ultraviolet absorber contained in the weather-resistant layer.

4. The polycarbonate resin laminate for hot bending process according to claim 1 or 2, A polycarbonate resin laminate for hot bending processability, wherein the content of an ultraviolet absorber contained in the base layer is 1 mass % or less with respect to the total amount of the base layer.

5. The polycarbonate resin laminate for hot bending process according to claim 1 or 2, L of the polycarbonate resin laminate for heat bending ＊ a ＊ b ＊ a in the color system ＊ Values are -6 to 1, b ＊ A polycarbonate resin laminate for hot bending process, having a value of -8 to 2.

5.

6. The polycarbonate resin laminate for hot bending process according to claim 1 or 2, A polycarbonate resin laminate for use in hot bending, wherein the thickness (μm) of the weather-resistant layer is 0.06 to 3.5% of the total thickness (μm) of the polycarbonate resin laminate for use in hot bending.

7. The polycarbonate resin laminate for hot bending process according to claim 1 or 2, The polycarbonate resin laminate for hot bending processability, wherein the thickness (μm) of the weather-resistant layer is 10 to 100 μm.

8. The polycarbonate resin laminate for hot bending process according to claim 1 or 2, The polycarbonate resin laminate for heat bending processability, wherein the ultraviolet absorber contained in the weather-resistant layer is a triazine-based ultraviolet absorber.

9. The polycarbonate resin laminate for hot bending process according to claim 1 or 2, The polycarbonate resin laminate for hot bending processability is obtained by laminating the base layer and the weather-resistant layer by co-extrusion molding.

10. The polycarbonate resin laminate for hot bending process according to claim 1 or 2, a transition layer between the hard coat layer and the weather resistant layer; A polycarbonate resin laminate for hot bending processability, wherein the transition layer contains at least a portion of the components of the hard coat layer and at least a portion of the components of the weather-resistant layer.

11. A curved member obtained by heat bending the polycarbonate resin laminate for heat bending process according to claim 1 or 2.

12. A method for producing a polycarbonate resin laminate for hot bending process, in which a substrate layer containing a polycarbonate resin, a weather-resistant layer, and a hard coat layer are laminated in this order, comprising: a step of co-extrusion molding a resin composition for a base layer and a resin composition for a weather-resistant layer to laminate the base layer and the weather-resistant layer; applying a resin composition for a hard coat layer to a surface of the laminated weather-resistant layer opposite to the substrate layer to form a hard coat layer on the substrate layer; Including, The method for producing a polycarbonate resin laminate for heat bending processability, wherein the weather-resistant layer contains a polycarbonate resin and an ultraviolet absorber.

13. A method for producing a curved member, comprising the step of hot bending a polycarbonate resin laminate for hot bending process obtained by the method for producing a polycarbonate resin laminate for hot bending process according to claim 12 to form a curved member.

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