Multilayer products and dust covers for head-up displays.

Abstract

DEPCT68 Provided are multi-layer products and dust covers for head-up displays. Use a multi-layer product; a multi-layer product containing layers of polycarbonate resin. And metal salts of sulfonic acid and an acrylic resin layer with a thickness of 1 to 80 micrometers and containing... Acrylic resin in which the amount of metal salts of sulfonic acid in the polycarbonate resin layer is 0.01 to 0.80 percent by mass and the cloudiness of the multilayer product is 20 percent or less. that;

Description

Multilayer body and dustproof cover for head-up display

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

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

[0003] On the other hand, polycarbonate resins generally have low surface hardness, so that the surfaces of molded products made of polycarbonate resins tend to be easily scratched. Therefore, when polycarbonate resins are formed into films, it has been considered to form a layer containing an acrylic resin or a hard coat layer (protective layer) on the surface to prevent scratches on the product surface. Such multilayer bodies are described in Patent Documents 1 and 2.

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

[0005] Here, a multilayer body having a layer containing a polycarbonate resin (polycarbonate resin layer) and a layer containing an acrylic resin (acrylic resin layer) may be required to have flame retardancy. Furthermore, such a multilayer body is also required to have transparency. The present invention aims to solve this problem by providing a multilayer body having excellent flame retardancy and high transparency, and a dustproof cover for a head-up display using the same.

[0006] In light of the above-mentioned problem, the present inventors conducted research and found that acrylic resin layers are more flammable than polycarbonate resin layers. However, even when a flame retardant was incorporated into the acrylic resin layer, it was difficult to obtain a multilayer body that met Federal Motor Vehicle Safety Standards (FMVSS). Furthermore, the inventors conducted research and found that the above-mentioned problem could be solved by incorporating a specific flame retardant into the polycarbonate resin layer and reducing the thickness of the acrylic resin layer. Specifically, the above-mentioned problem was solved by the following means. <1> A multilayer body having a polycarbonate resin layer containing a polycarbonate resin and a metal sulfonate salt, and an acrylic resin layer having a thickness of 1 to 80 μm and containing an acrylic resin, wherein the content of the metal sulfonate salt in the polycarbonate resin layer is 0.01 to 0.80 mass %, and the haze of the multilayer body is 20% or less. <2> The multilayer body according to <1>, wherein the haze of the multilayer body is 10% or less. <3> The multilayer body according to <1> or <2>, wherein the thickness of the acrylic resin layer is 10 to 80 μm. <4> The multilayer body according to any one of <1> to <3>, wherein the pencil hardness measured from the acrylic resin layer side of the multilayer body is F or more. <5> The multilayer body according to any one of <1> to <4>, wherein the acrylic resin layer of the multilayer body contains a flame retardant. <6> The multilayer body according to <1> or <2>, wherein the thickness of the acrylic resin layer is 1 μm or more and less than 10 μm. <7> The multilayer body according to <6>, wherein the acrylic resin layer of the multilayer body is substantially free of a flame retardant. <8> The multilayer body according to any one of <1> to <7>, further comprising a hard coat layer. <9> A dustproof cover for a head-up display, comprising the multilayer body according to any one of <1> to <8>.

[0007] The present invention makes it possible to provide a multilayer body that is excellent in flame retardancy and transparency, and a dustproof cover for a head-up display that uses the same.

[0008] FIG. 1 is a diagram schematically illustrating the layer structure of the multilayer body of the present invention.

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

[0010] The multilayer body of this embodiment comprises a polycarbonate resin layer containing a polycarbonate resin and a metal sulfonate salt, and an acrylic resin layer having a thickness of 1 to 80 μm and containing an acrylic resin, wherein the content of the metal sulfonate salt in the polycarbonate resin layer is 0.01 to 0.80 mass %, and the haze of the multilayer body is 20% or less. This configuration results in a multilayer body with excellent flame retardancy and high transparency. Acrylic resins are inherently flammable, and it is difficult to achieve flame retardancy sufficient to pass the FMVSS test by simply adding a flame retardant to the acrylic resin layer. Therefore, in this embodiment, by adding a flame retardant to the polycarbonate resin layer and thinning the acrylic resin layer, it is possible to pass the FMVSS test. Needless to say, even if a product does not pass the FMVSS test, it is within the scope of the present invention as long as it achieves the effects of the present invention. Furthermore, adding a large amount of flame retardant to the polycarbonate resin layer results in poor transparency. In this embodiment, by using a metal sulfonate as the flame retardant, it is possible to exhibit flame retardancy with the addition of a small amount, and a multilayer body having excellent transparency can be obtained.

[0011] <Polycarbonate Resin Layer> The polycarbonate resin layer in this embodiment contains a polycarbonate resin and a metal sulfonate, and the content of the metal sulfonate in the polycarbonate resin layer is 0.01 to 0.80% by mass.

[0012] The polycarbonate resin is not particularly limited as long as it contains an —[O—R—OCO]— structural unit (R is a hydrocarbon group (for example, an aliphatic group, an aromatic group, or one containing both an aliphatic group and an aromatic group, and further, one having a linear structure or a branched structure)) that contains a carbonate ester bond in the molecular main chain, and various polycarbonate resins can be used.

[0013] In this embodiment, the polycarbonate resin preferably contains a bisphenol-type polycarbonate resin. A bisphenol-type polycarbonate resin is one 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 (preferably bisphenol A) and / or its derivatives. The bisphenol-type polycarbonate resin is preferably a bisphenol A-type polycarbonate resin.

[0014] The molecular weight of the polycarbonate resin is not particularly limited, but is preferably 20,000 or more, more preferably 22,000 or more, in terms of viscosity average molecular weight calculated from the solution viscosity measured at 25°C using methylene chloride as a solvent. The viscosity average molecular weight is preferably 35,000 or less, more preferably 32,000 or less, and even more preferably 30,000 or less, and may be 28,000 or less, or 25,000 or less. By setting the viscosity average molecular weight to the lower limit or more, the strength of the resulting flat molded article can be increased. Setting the viscosity average molecular weight to the upper limit or less tends to improve moldability. Here, the viscosity average molecular weight [Mv] is calculated by using methylene chloride as a solvent and an Ubbelohde viscometer to determine the intrinsic viscosity [η] (unit: dL / g) at 25°C, and then calculating the viscosity average molecular weight using Schnell's viscosity formula, i.e., η = 1.23 × 10. －４ Mv ０．８３ The intrinsic viscosity [η] is the specific viscosity [η] at each solution concentration [C] (g / dL). ｓｐ ] was measured and the value was calculated according to the following formula. In this embodiment, two or more polycarbonate resins having different viscosity average molecular weights may be mixed and used, and in this case, the viscosity average molecular weight is the viscosity average molecular weight of the mixture.

[0015] The onset 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, even more preferably 151 ° C. or less, and may be 150 ° C. or less, 149 ° C. or less. The onset glass transition temperature (Tg) of the polycarbonate resin used in this embodiment is, for example, 140 ° C. or more, or even 143 ° C. or more, 145 ° C. or more, 147 ° C. or more, or 148 ° C. or more. The glass transition temperature is measured according to the description in paragraph 0056 of JP 2022-080270 A.

[0016] For details of the polycarbonate resin, the descriptions in paragraphs 0011 to 0020 of JP-A-2012-144604 and the descriptions in paragraphs 0014 to 0035 of JP-A-2019-002023 can be referred to as long as they do not deviate from the spirit of this embodiment, and the contents of these can be incorporated into this specification.

[0017] In this embodiment, the content of polycarbonate resin in the polycarbonate resin layer is preferably 90% by mass or more, more preferably 92% by mass or more, even more preferably 94% by mass or more, even more preferably 96% by mass or more, still more preferably 97% by mass or more, and may even be 98% by mass or more, based on 100% by mass of the polycarbonate resin layer. The upper limit is the amount of components other than the sulfonic acid metal salt in the polycarbonate resin layer that become polycarbonate resin. When the polycarbonate resin layer in this embodiment contains two or more types of polycarbonate resin, it is preferable that the total amount be within the above range.

[0018] The polycarbonate resin layer in this embodiment contains a metal sulfonate, which is a component generally used as a flame retardant for polycarbonate resins.

[0019] The metal sulfonate is preferably an alkali metal salt. The alkali metal constituting the alkali metal salt is preferably lithium, sodium, potassium, or rubidium, and more preferably sodium or potassium. The metal sulfonate may also contain a fluorine atom. The molecular weight of the metal sulfonate used in this embodiment is preferably 100 to 900, and more preferably 100 to 500.

[0020] Specific examples of the metal sulfonate salt used in this embodiment are shown below. It goes without saying that the metal sulfonate salt used in this embodiment is not limited to these.

[0021] The content of the metal sulfonate in the polycarbonate resin layer is 0.01 to 0.80% by mass, preferably 0.7% by mass or less, 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 0.05% by mass or less. By using a metal sulfonate, excellent flame retardancy can be achieved even with a reduced amount of flame retardant incorporated into the polycarbonate resin layer, resulting in a multilayer body with excellent transparency and moist heat resistance. The polycarbonate resin layer in this embodiment may contain only one type of metal sulfonate, or two or more types. When two or more types are contained, the total amount preferably falls within the above range.

[0022] The polycarbonate resin layer in this embodiment may or may not contain a flame retardant other than a metal sulfonate. Examples of flame retardants other than a metal sulfonate include phosphorus-based flame retardants and halogen-based flame retardants. An example of the polycarbonate resin layer in this embodiment is a form in which a metal sulfonate and a phosphorus-based flame retardant are used in combination. It is preferable that the polycarbonate resin layer in this embodiment is substantially free of flame retardants other than a metal sulfonate. "Substantially free" means that the content of flame retardants other than a metal sulfonate is 50% by mass or less of the total amount of flame retardants contained in the polycarbonate resin layer, preferably 10% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less.

[0023] In addition to the above components, the polycarbonate resin layer in this embodiment may contain antioxidants, release agents, UV absorbers, flame retardant aids, heat stabilizers, colorants, antistatic agents, fluorescent brighteners, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact improvers, sliding improvers, hue improvers, acid trapping agents, etc. These components may be used alone or in combination of two or more. The total content of the above components is preferably 0 to 5% by mass of the polycarbonate resin layer, more preferably 0 to 3% by mass, even more preferably 0 to 1% by mass, even more preferably 0 to 0.5% by mass, even more preferably 0 to 0.3% by mass, and even more preferably 0 to 0.1% by mass.

[0024] Examples of antioxidants include phenol-based antioxidants, amine-based antioxidants, phosphorus-based antioxidants, thioether-based antioxidants, etc. Among these, in the present embodiment, phosphorus-based antioxidants and phenol-based antioxidants (more preferably hindered phenol-based antioxidants) are preferred, and phosphorus-based antioxidants are more preferred.

[0025] The phosphorus-based antioxidant is preferably a phosphite-based antioxidant, and a phosphite compound represented by the following formula (1) or (2) is preferred. (In formula (1), R １１ and R１２ each independently represents an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms. (In formula (2), R １３ ~R １７ each independently represents a hydrogen atom, an aryl group having 6 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms.

[0026] In the above formula (1), R １１ , R １２ Each of the alkyl groups represented by the formula (I) is preferably a linear or branched alkyl group having 1 to 10 carbon atoms. １１ , R １２ When is an aryl group, it is preferably an aryl group represented by any one of the following formulae (1-a), (1-b), and (1-c): * in the formula represents the bonding position.

[0027] (In formula (1-a), R Ａ each independently represents an alkyl group having 1 to 10 carbon atoms. Ｂ each independently represents an alkyl group having 1 to 10 carbon atoms.

[0028] For the hindered phenol-based antioxidant, reference can be made to the descriptions in paragraph 0063 of JP-A-2018-090677 and paragraph 0076 of JP-A-2018-188496, the contents of which are incorporated herein by reference.

[0029] In addition to the above, the antioxidants can be found in paragraphs 0057 to 0061 of JP 2017-031313 A, the contents of which are incorporated herein by reference.

[0030] The content of the antioxidant is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, even more preferably 0.010 parts by mass or more, and even more preferably 0.050 parts by mass or more, relative to 100 parts by mass of the polycarbonate resin layer. The upper limit of the antioxidant content is preferably 0.500 parts by mass or less, more preferably 0.300 parts by mass or less, even more preferably 0.200 parts by mass or less, even more preferably 0.150 parts by mass or less, even more preferably 0.100 parts by mass or less, and particularly preferably 0.080 parts by mass or less, relative to 100 parts by mass of the polycarbonate resin layer. One or more antioxidants may be used. When two or more antioxidants are used, the total amount is preferably within the above range.

[0031] Next, the release agent that can be contained in the polycarbonate resin layer will be described. The type of release agent is not particularly limited, but examples include aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds with a number average molecular weight of 200 to 15,000, polyethers with a number average molecular weight of 100 to 5,000, and polysiloxane-based silicone oils.

[0032] For details of the release agent, please refer to paragraphs 0035 to 0039 of WO 2015 / 190162, the contents of which are incorporated herein by reference.

[0033] The content of the release agent is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, even more preferably 0.010 parts by mass or more, and even more preferably 0.050 parts by mass or more, relative to 100 parts by mass of the polycarbonate resin layer. The upper limit is preferably 0.5 parts by mass or less, more preferably 0.3 parts by mass or less, and even more preferably 0.1 parts by mass or less. Only one type of release agent may be used, or two or more types may be used. When two or more types are used, it is preferable that the total amount be within the above range.

[0034] The thickness of the polycarbonate resin layer is preferably 50 μm or more, more preferably 100 μm or more, and even more preferably 200 μm or more. By making the thickness equal to or greater than the lower limit, molding becomes easier and flame retardancy tends to be improved. Furthermore, the upper limit of the thickness of the polycarbonate resin layer is preferably 1000 μm or less, more preferably 750 μm or less, and even more preferably 500 μm or less.

[0035] <Acrylic Resin Layer> The acrylic resin layer in this embodiment has a thickness of 1 to 80 μm and contains an acrylic resin.

[0036] The thickness of the acrylic resin layer is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 10 μm or more, even more preferably 20 μm or more, even more preferably 25 μm or more, and even more preferably 30 μm or more. By making the thickness equal to or greater than the lower limit, molding becomes easier and hardness tends to be improved. Furthermore, the upper limit of the thickness of the acrylic resin layer is 80 μm or less, preferably 70 μm or less, more preferably 60 μm or less, and may be 55 μm or less, 50 μm or less, 45 μm or less, or 40 μm or less, or may be less than 10 μm depending on the application, etc. By reducing the thickness of the acrylic resin layer in this way, the flame retardancy of the multilayer body can be improved.

[0037] The acrylic resin layer may be a single layer or may be a multilayer, but is preferably a single layer.

[0038] As described above, the acrylic resin layer in this embodiment contains an acrylic resin. An example of the acrylic resin is a polymer containing 50% by mass or more (preferably 90% by mass or more, more preferably 95% by mass or more) of all structural units of alkyl (meth)acrylate units (preferably alkyl methacrylate units, also preferably alkyl (meth)acrylate units having an alkyl group of 1 to 3 carbon atoms, more preferably alkyl methacrylate units having an alkyl group of 1 to 3 carbon atoms), and more preferably a polymer containing 50% by mass or more (preferably 90% by mass or more) of all structural units of methyl (meth)acrylate units (preferably methyl methacrylate units). Examples of structural units other than alkyl (meth)acrylate units include other (meth)acrylate units, styrene units, cyclic acid anhydride units, N-substituted maleimide units, and lactone ring units. When the acrylic resin layer of this embodiment is multilayered (composed of two or more layers), it is preferable that all of the acrylic resin layers contain the above-mentioned acrylic resin.

[0039] The acrylic resin layer may be made of only an acrylic resin, or may contain, in addition to the acrylic resin, other thermoplastic resins, preferably at least one thermoplastic resin selected from a styrene-based resin, a fluorine-based resin such as polyvinylidene fluoride, and an aromatic polyether resin such as polyphenylene ether, and more preferably a styrene-based resin.

[0040] An example of the acrylic resin layer is a layer composed of 90% by mass or more (preferably 95% by mass or more, more preferably 97% by mass or more, and even more preferably 98% by mass or more) of an acrylic resin. Another example of the acrylic resin is a layer composed of 90% by mass or more (preferably 95% by mass or more, more preferably 97% by mass or more, and even more preferably 98% by mass or more) of the acrylic resin and another thermoplastic resin (preferably a styrene-based resin).

[0041] The weight-average molecular weight of the acrylic resin is not particularly limited, but is preferably 10,000 or more, more preferably 30,000 or more, even more preferably 50,000 or more, still more preferably 60,000 or more, and even more preferably 70,000 or more. The weight-average molecular weight of the acrylic resin is preferably 250,000 or less, more preferably 200,000 or less, even more preferably 150,000 or less, still more preferably 100,000 or less, and even more preferably 90,000 or less.

[0042] The glass transition temperature of the acrylic resin layer used in this embodiment is preferably 80°C or higher, more preferably 90°C or higher, even more preferably 95°C or higher, even more preferably 100°C or higher, and even more preferably 105°C or higher. The upper limit is not particularly specified, but, for example, 200°C or lower is practical. The glass transition temperature is measured according to the description in paragraph 0056 of JP 2022-080270 A.

[0043] In addition to the above components, the acrylic resin layer may contain inorganic particles, antioxidants, release agents, ultraviolet absorbers, heat stabilizers, flame retardants, flame retardant aids, colorants, antistatic agents, fluorescent brighteners, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact improvers, sliding improvers, hue improvers, acid trapping agents, etc. These components may be used alone or in combination of two or more. When contained, the total content of the above components is preferably 0.1 to 5% by mass of the acrylic resin layer.

[0044] As described above, the acrylic resin layer in this embodiment may contain a flame retardant. Examples of the flame retardant that may be contained in the acrylic resin layer include phosphorus-based flame retardants. Examples of phosphorus-based flame retardants include aromatic phosphate ester compounds, phosphaphenanthrene compounds, metal phosphinates, ammonium polyphosphate, melamine polyphosphate, phosphate ester amide, and red phosphorus, with aromatic phosphate ester compounds and phosphaphenanthrene compounds being preferred.

[0045] Examples of aromatic phosphate ester compounds include resorcinol diphenyl phosphate, hydroquinone diphenyl phosphate, bisphenol A diphenyl phosphate, biphenyl diphenyl phosphate, etc. Commercially available products thereof include PX-202, CR-741, PX-200, and PX-201 manufactured by Daihachi Chemical Industry Co., Ltd., and FP-500, FP-600, FP-700, and PFR manufactured by ADEKA Corporation.

[0046] Phosphaphenanthrene compounds are phosphorus-based flame retardants having at least one phosphaphenanthrene skeleton in the molecule, and commercially available products include HCA, HCA-HQ, BCA, SANKO-220, and M-Ester manufactured by Sankosha.

[0047] The metal phosphinate salt is a phosphinate salt and / or a diphosphinate salt and / or a polymer thereof. Examples of the salt include calcium, aluminum, and zinc salts. Commercially available metal phosphinate salts include "Exolit" (registered trademark) OP1230 and OP1240 manufactured by Clariant Japan.

[0048] Phosphate ester amide is an aromatic amide-based flame retardant containing a phosphorus atom and a nitrogen atom. A commercially available phosphorus ester amide product such as SP-703 manufactured by Shikoku Kasei Co., Ltd. is preferably used.

[0049] Examples of ammonium polyphosphate include ammonium polyphosphate, melamine-modified ammonium polyphosphate, and carbamyl ammonium polyphosphate. Examples of the melamine polyphosphate include melamine phosphate, melamine pyrophosphate, and melamine polyphosphates such as melamine, melam, and melem phosphates. Products such as MPP-A manufactured by Sanwa Chemical Co., Ltd. and PMP-100 and PMP-200 manufactured by Nissan Chemical Industries, Ltd. are preferably used.

[0050] When the acrylic resin layer contains a flame retardant, the content thereof is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 5 parts by mass or more, and even more preferably 7 parts by mass or more, per 100 parts by mass of the acrylic resin layer. The upper limit of the content of the flame retardant is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, per 100 parts by mass of the acrylic resin layer. The acrylic resin layer may contain only one type of flame retardant, or two or more types. When two or more types are contained, the total amount is preferably within the above range. The multilayer body of this embodiment can also be configured so that the acrylic resin layer is substantially free of flame retardants. "Substantially free" means that the content of the flame retardant in the acrylic resin layer is less than 1 part by mass, preferably 0.1 parts by mass or less, and even more preferably 0.01 parts by mass or less, per 100 parts by mass of the acrylic resin layer. This embodiment is valuable in that flame retardancy can be achieved without substantially blending a flame retardant into the flammable acrylic resin layer. Furthermore, when the content of the flame retardant in the acrylic resin layer is low, roll contamination during production can be effectively suppressed. Furthermore, when the thickness of the acrylic resin layer is, for example, less than 20 μm, further less than 10 μm, particularly 8 μm or less, it is preferable that the acrylic resin layer is substantially free of a flame retardant.

[0051] <Multilayer body> As described above, the multilayer body of this embodiment has a polycarbonate resin layer and an acrylic resin layer. There is no particular limitation on the thickness (total thickness) of the multilayer body, but it is preferably 30 μm or more, and more preferably 100 μm or more. Furthermore, the thickness of the multilayer body is preferably 10,000 μm or less, more preferably 5,000 μm or less, and even more preferably 2,000 μm or less, and may be 1,000 μm or less, or 500 μm or less.

[0052] The multilayer body of this embodiment preferably has high (hard) pencil hardness. The pencil hardness measured from the acrylic resin layer side is preferably F or higher, and more preferably H or higher. There is no particular upper limit, but a practical upper limit is 3H or lower.

[0053] The multilayer body of this embodiment also preferably has excellent transparency. Specifically, the haze of the multilayer body is 20% or less, preferably 10% or less, more preferably 5% or less, even more preferably 3% or less, even more preferably 2% or less, even more preferably 1.5% or less, even more preferably 1% or less, particularly preferably 0.8% or less, and may even be 0.5% or less. The lower limit is preferably 0% or more, but more than 0% is practical.

[0054] The multilayer body of this embodiment also preferably has excellent flame retardancy. Specifically, the multilayer body preferably satisfies a C rating in the FMVSS test (burns up to the B standard line but has a burning rate of 102 mm / min or less), more preferably a B rating in the FMVSS test (self-extinguishing with a burning distance of 51 mm or less (and within 60 seconds) from the A standard line), and even more preferably an A rating (the test piece does not ignite or self-extinguishes just before the A standard line). The pencil hardness, haze, and FMVSS test are measured according to the descriptions in the examples below.

[0055] The multilayer body of this embodiment may further include a hard coat layer. The hard coat layer is preferably present on at least one surface of the multilayer body. The hard coat layer may be the outermost layer of the multilayer body. Providing a hard coat layer tends to further improve the surface hardness of the multilayer body. In the multilayer body of this embodiment, the hard coat layer is preferably laminated in the following order: a polycarbonate resin layer, an acrylic resin layer, and a hard coat layer. In the multilayer body of this embodiment, the hard coat layer is preferably provided on the surface of the acrylic resin layer. Providing a hard coat layer on the surface of the acrylic resin layer can further improve the coatability of the hard coat layer. FIG. 1 is a schematic diagram showing an example of the multilayer body of this embodiment, where, as described above, 1 indicates the multilayer body, 2 indicates the polycarbonate resin layer, 3 indicates the acrylic resin layer, and 4 indicates the hard coat layer. The polycarbonate resin layer 2, the acrylic resin layer 3, and the hard coat layer 4 may include other layers as long as they are laminated in the above order without departing from the spirit of this embodiment; however, it is preferable that they do not include other layers, i.e., that they are adjacent to each other.

[0056] The hard coat layer that may be included in the multilayer body of this embodiment has a surface hardness higher than that of the polycarbonate resin layer. By including such a hard coat layer, the surface hardness of the multilayer body or molded article can be increased. Furthermore, by including a hard coat layer with a higher surface hardness, flame retardancy tends to be further improved. The thickness of the hard coat layer is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 2 μm or more, even more preferably 2.5 μm or more, and even more preferably 3 μm or more. By setting the thickness at or above the lower limit, the pencil hardness of the entire multilayer body due to the hard coat layer tends to be further improved. The upper limit of the thickness of the hard coat layer is preferably 20 μm or less, more preferably 15 μm or less, even more preferably 12 μm or less, even more preferably 10 μm or less, even more preferably 8 μm or less, and may even be 5 μm or less. By setting the thickness at or below the upper limit, flame retardancy tends to be further improved.

[0057] The hard coat layer is preferably obtained by applying and curing a hard coat material that can be cured by heat or active energy rays. Examples of coating materials that can be cured using active energy rays include resin compositions composed of a single or multiple monofunctional or polyfunctional (preferably di- to decafunctional) (meth)acrylate monomers or oligomers, and preferred examples include resin compositions containing monofunctional or polyfunctional (preferably di- to decafunctional) urethane (meth)acrylate oligomers. These resin compositions preferably contain a photopolymerization initiator as a curing catalyst. Examples of thermosetting resin coating materials include polyorganosiloxane-based and crosslinked acrylic-based coatings. Such resin compositions are commercially available as hard coat agents for acrylic or polycarbonate resin films or sheets, and can be selected appropriately taking into account suitability for the coating line. For the hard coat layer, the descriptions in paragraphs 0045 to 0055 of JP-A-2013-020130, the descriptions in paragraphs 0073 to 0076 of JP-A-2018-103518, and the descriptions in paragraphs 0062 to 0082 of JP-A-2017-213771 can be referred to, and the contents of these can be incorporated into this specification.

[0058] In addition to the above components, the hard coat layer may contain inorganic particles, organic pigments, ultraviolet absorbers, light stabilizers, heat stabilizers, flame retardants, flame retardant assistants, colorants, antistatic agents, fluorescent brighteners, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact improvers, sliding improvers, hue improvers, acid trapping agents, etc. These components may be used alone or in combination of two or more.

[0059] Preferred examples of inorganic particles include nanoparticles made of metals 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 made of two or more of these. Preferred examples of metal compounds include iron oxide, silicon oxide, zirconium oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, cobalt oxide, nickel oxide, cerium oxide, cupric oxide, zinc oxide, tin oxide, antimony oxide, titanium dioxide, aluminum oxide, indium tin oxide (ITO), cesium tungsten oxide (CWO), and mixtures thereof, and other metal oxides, metal carbides, metal borides, metal carbonates, zeolites, clays, and composites thereof.

[0060] Examples of flame retardants include halogen-based flame retardants and phosphorus-based flame retardants. Phosphorus-based flame retardants include aromatic phosphate ester compounds, phosphaphenanthrene compounds, metal phosphinates, ammonium polyphosphate, melamine polyphosphate, phosphate ester amides, and red phosphorus. For flame retardants, see paragraphs 0054 to 0082 of JP 2022-104214 A and paragraphs 0052 to 0077 of Japanese Patent No. 7021724, the contents of which are incorporated herein by reference.

[0061] The multilayer body of this embodiment may have a near-infrared cut layer. The near-infrared cut layer is preferably a layer containing a near-infrared absorber. An example of the infrared cut layer is a hard coat layer to which a near-infrared absorber (e.g., cesium tungsten oxide (CWO)) is blended. When the hard coat layer contains a near-infrared absorber, the multilayer body can cut near-infrared rays, and can be more preferably used as a dustproof cover for a head-up display.

[0062] The multilayer body of the present embodiment may have other layers in addition to those described above, such as an adhesive layer, a pressure-sensitive adhesive layer, an antifouling layer, and the like.

[0063] The multilayer body may also be subjected to one or more of anti-fingerprint treatment, anti-glare treatment, weather-resistant treatment, antistatic treatment, anti-fouling treatment, and anti-blocking treatment on at least one surface thereof. An example of the outermost surface of the multilayer body in this case is a hard coat layer. The anti-blocking treatment refers to a treatment that allows films to be easily peeled even when they are in close contact with each other, and examples include adding an anti-blocking agent or providing irregularities on the surface of the multilayer body. The multilayer body of this embodiment can be formed by using a main extruder that extrudes a polycarbonate resin layer-forming composition and a sub-extruder that extrudes an acrylic resin layer-forming composition, melting the resins under the conditions of the resins used, introducing them into an extrusion die, laminating them inside the die and forming them into a sheet, or laminating them into a sheet.

[0064] The multilayer body of the present embodiment may be used as it is, but can also be processed, particularly by heat processing, to form a molded article. The molded article of the present embodiment is a molded article formed from the multilayer body of the present embodiment.

[0065] <Applications> The multilayer body or molded article of this embodiment can be suitably used for optical parts, decorative products, anti-reflection molded bodies, etc. The multilayer body of this embodiment can be suitably used for parts such as display devices, electrical and electronic devices, office automation equipment, mobile information terminals, machine parts, home appliances, vehicle parts, various containers, and lighting equipment. Among these, it is particularly suitable for use in housings for various displays, electrical and electronic devices, office automation equipment, mobile information terminals, and home appliances, lighting equipment, and vehicle parts (particularly vehicle interior parts), surface films for smartphones and touch panels, etc., optical materials, and optical discs. In particular, the multilayer body of this embodiment can be suitably used as a dustproof cover for head-up displays.

[0066] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

[0067] 1. Raw materials Polycarbonate resin E-2000F: Polycarbonate resin obtained by interfacial polymerization using bisphenol A as a starting material (manufactured by Mitsubishi Gas Chemical Company, Inc., E-2000F, viscosity average molecular weight: 27,000, Tg: 150°C) S-3000F: Polycarbonate resin obtained by interfacial polymerization using bisphenol A as a starting material (manufactured by Mitsubishi Gas Chemical Company, Inc., S-3000F, viscosity average molecular weight: 21,000, Tg: 147°C)

[0068] Metal sulfonate KSS-FR: KSS-FR manufactured by Arichem, potassium diphenylsulfone-3-sulfonate NATS: NATS manufactured by Tokyo Chemical Industry Co., Ltd., sodium p-toluenesulfonate F-114P: F-114P manufactured by DIC Corporation, potassium perfluorobutanesulfonate

[0069] Phosphorus-based flame retardant PX-200: manufactured by Daihachi Chemical Industry Co., Ltd., the following compound

[0070] Antioxidant 2112: Tris(2,4-di-tert-butylphenyl)phosphite (phosphorus-based antioxidant, Adeka Stab 2112 manufactured by ADEKA Corporation)

[0071] Release agent S-100A: Glycerin monostearate (Rikemal S-100A, manufactured by Riken Vitamin Co., Ltd.)

[0072] Acrylic resin PMMA: Polymethyl methacrylate, manufactured by Asahi Kasei Corporation, Delpet 80HD Flame retardant BCA: The following compound manufactured by Sanko Co., Ltd.

[0073] 2. Examples 1 to 10, Comparative Examples 1 to 10 <Production of Resin Compositions (Pellets)> A resin composition (pellet) for forming a polycarbonate resin layer and a resin composition (pellet) for forming an acrylic resin layer were produced according to the following method. Each of the components described above was weighed out to the amount shown in Table 1 or Table 2 (each component in Tables 1 and 2 is expressed in mass %). The mixture was then mixed in a tumbler for 15 minutes, melt-kneaded in a vented twin-screw extruder with a screw diameter of 32 mm ("TEX30α" manufactured by The Japan Steel Works, Ltd.), and pellets were obtained by strand cutting. The resin composition (pellet) for forming a polycarbonate resin layer was melt-kneaded at 260 to 300°C, with the temperature being changed as needed depending on the resin viscosity, while the resin composition (pellet) for forming an acrylic resin layer was melt-kneaded at 260°C.

[0074] <Production of Multilayer Body> A multilayer body was molded using a multilayer extrusion device equipped with a single-screw extruder with a 32 mm shaft diameter, a single-screw extruder with a 65 mm shaft diameter, a feed block connected to all extruders, and a 650 mm-wide T-die connected to the feed block. The resin composition (pellets) used to form the acrylic resin layer in each Example and Comparative Example shown in Table 1 or Table 2 was introduced into the single-screw extruder with a 32 mm shaft diameter and extruded at a cylinder temperature of 240°C and a throughput of 0.3 to 6.4 kg / h. The resin composition (pellets) used to form the polycarbonate resin layer in each Example and Comparative Example shown in Table 1 or Table 2 was continuously introduced into the single-screw extruder with a 65 mm shaft diameter and extruded at a throughput of 17.4 to 23.5 kg / h, while the cylinder temperature was changed from 250°C to 290°C depending on the resin viscosity. The feed block connected to all extruders was equipped with two-type, two-layer distributor pins, and the extrusion was laminated. The extrusion was carried out into a sheet form through a T-die connected to the end of the die, and cooled while transferring a mirror surface using three mirror-finished rolls set at temperatures of 120°C, 120°C, and 140°C from the upstream side, to obtain each multilayer body. The rolls used in the production were also visually inspected for roll contamination. Five experts evaluated the rolls and made a majority decision. The results are shown in the table below as roll contamination.

[0075] <Pencil Hardness> The pencil hardness of the acrylic resin layer side of the multilayer body prepared above was measured using a pencil hardness tester under a load of 750 g in accordance with JIS K5600-5-4: 1999. The evaluation was carried out by five experts, and judged by majority vote.

[0076] <FMVSS Test> Using an FMVSS No. 302 flammability tester, the multilayer body obtained above was measured for a burning distance of 254 mm between the gauge lines by applying a burner flame 38 mm from the right end of the test piece (350 mm x 100 mm x 0.375 mm) for 15 seconds. The test jig was used without a wire, and the burning rate was measured as follows: A: The test piece did not ignite or self-extinguished just before the A standard line; B: The burning distance was within 51 mm (and within 60 seconds) from the A standard line; C: The test piece burned up to the B standard line, but the burning rate was 102 mm / min or less; D: The test piece burned up to the B standard line, but the burning rate was faster than 102 mm / min.

[0077] <Haze> The haze (unit: %) of the obtained multilayer body was measured under the conditions of a D65 light source and a 10° field of view using a haze meter ("HM-150" manufactured by Murakami Color Research Laboratory Co., Ltd.).

[0078] Comparative Example 11 <Production of Resin Composition (Pellets)> A resin composition (pellets) for forming a polycarbonate resin layer was produced in the same manner as in Example 1.

[0079] <Production of Multilayer Body> Using a T-die melt extruder consisting of a vented twin-screw extruder TEX30α (manufactured by The Japan Steel Works, Ltd.) with a barrel diameter of 32 mm and a screw L / D ratio of 31.5, the resin composition (pellets) used to form the polycarbonate resin layer was continuously introduced and extruded at a cylinder temperature of 280°C. The pellets were extruded into a sheet form through a T-die connected to the extruder, and cooled while transferring a mirror surface using three mirror-finishing rolls heated to 120°C, 120°C, and 140°C from the upstream side, to obtain a multilayer body. The resulting multilayer body was evaluated in the same manner as in Example 1.

[0080]

[0081]

[0082] Examples 11 to 13 <Preparation of Hard Coat A> 96 parts by mass of Nopcocure FC950 (urethane acrylate, solid content concentration 50% by mass, manufactured by San Nopco Ltd.), 2 parts by mass of Esacure One (photopolymerization initiator, manufactured by IGM Resins), and 2 parts by mass of RS-75A (fluorine-based leveling agent, solid content concentration 20% by mass, manufactured by DIC Corporation) were mixed, and then diluted with propylene glycol monoethyl ether to a solid content concentration of 25% by mass, to obtain a mixed solution.

[0083] <Preparation of Hard Coat B> HO3313U-10 (urethane acrylate, solid content concentration 52.6% by mass, manufactured by Fujikura Kasei Co., Ltd.) was diluted with propylene glycol monoethyl ether to a solid content concentration of 26.3% by mass to obtain a mixed solution.

[0084] <Formation of Hard Coat Layer> A multilayer body as shown in Table 3 was produced in the same manner as in Example 1 above. The mixed solution obtained by the hard coat solution preparation described above was applied to the acrylic resin layer side of the multilayer body using a bar coater so that the film thickness after drying would be 3 μm, and then dried in an oven at 80°C for 2 minutes. Subsequently, UV curing was performed using a Heraeus UV irradiator under a nitrogen atmosphere so that the integrated light dose was 200 mJ, thereby obtaining a multilayer body. The film thickness of the hard coat layer was 3 μm.

[0085] The FMVSS test, pencil hardness, and haze measurements were carried out in the same manner as in Example 1. The pencil hardness was measured on the side where the hard coat layer was provided. <Appearance of hard coat layer> The film after application of the hard coat was also evaluated for any appearance defects. The appearance defects of the hard coat layer were visually inspected. Upon confirmation, five experts evaluated and judged by majority vote, and the evaluation was made as follows: A: No appearance defects B: Appearance defects

[0086] Comparative Example 12 <Formation of Hard Coat Layer> A multilayer body as shown in Table 3 was produced in accordance with Comparative Example 11. The mixed solution obtained by the hard coat solution preparation described above was applied to the surface of the polycarbonate resin layer using a bar coater so that the film thickness after drying would be 3 μm, and then dried in an oven at 80°C for 2 minutes. Subsequently, UV curing was performed using a Heraeus UV irradiator under a nitrogen atmosphere so that the integrated light dose was 200 mJ, thereby obtaining a multilayer body. The film thickness of the hard coat layer was 3 μm. The obtained multilayer body was evaluated in the same manner as in Example 11.

[0087]

[0088] Example 14 The same procedure as in Example 1 was carried out except that the changes were made as shown in Table 4.

[0089] Example 15 The same procedure as in Example 13 was carried out except that the changes were made as shown in Table 4.

[0090]

[0091] In Tables 1 to 4, the PC layer refers to a polycarbonate resin layer, and in Tables 3 and 4, the HC layer refers to a hard coat layer. As is clear from the results above, the multilayer body of the present embodiment had excellent flame retardancy and transparency. Furthermore, the pencil hardness was also high.

[0092] 1 Multilayer body 2 Polycarbonate resin layer 3 Acrylic resin layer 4 Hard coat layer

Claims

DEPCT681. Multilayer products consisting of a polycarbonate resin layer incorporating polycarbonate resin and sulfonic acid metal salts and an acrylic resin layer with a thickness of 1 to 80 micrometers, incorporating acrylic resin, with the content of sulfonic acid metal salts in the polycarbonate resin layer being 0.01 to 0.80 percent by mass, where the cloudiness of the multilayer product is 20 percent or less.

2. Multilayer products according to claim 1, where the cloudiness of the multilayer product is 10 percent or less.

3. Multilayer products under Reputation 1 or 2 where the acrylic resin layer is 10 to 80 micrometers thick.

4. Multilayer products under any of Reputation 1 to 3 where the pencil hardness of the multilayer product, as measured from the acrylic resin layer side, is F or harder.

5. Multilayer products under any of Reputation 1 to 4 where the acrylic resin layer of the multilayer product is flame retardant.

6. Multilayer products under Reputation 1 or 2 where the acrylic resin layer is 1 to 10 micrometers thick. 7.Multilayer products under claim 6 in which the acrylic resin layer of the multilayer product does not contain significant flame retardants; 8. Multilayer products under any of claims 1 through 7 that also contain one or more hard coating layers; 9. Dust covers for head-up displays that incorporate multilayer products under any of claims 1 through 8.

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