Multilayer dust cover for head-up display

Abstract

The present invention relates to: a multilayer body comprising a polycarbonate resin layer containing a polycarbonate resin and a metal sulfonate, and an acrylic resin layer having a thickness of 1-80 [mu] m and containing an acrylic resin, the content of the metal sulfonate in the polycarbonate resin layer being 0.01-0.80% by mass; the haze of the multilayer body is 20% or less.

Description

Technical Field

[0001] The present invention relates to a multi-layer body and a dust cover for a head-up display. In particular, it relates to a multi-layer body having a polycarbonate resin layer and an acrylic resin layer. Background Art

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

[0003] On the other hand, since polycarbonate resin usually has a low surface hardness, the surface of a molded product made of polycarbonate resin is often easily scratched. Therefore, technologies for forming a layer containing acrylic resin, a hard coat (protective layer), etc. on the surface have been continuously studied in the case where polycarbonate resin is formed into a film shape to prevent the surface of the product from being scratched. Such multi-layer bodies are described in Patent Document 1 and Patent Document 2.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: International Publication No. 2016 / 060100

[0007] Patent Document 2: International Publication No. 2021 / 215435 Summary of the Invention

[0008] Technical Problem to be Solved by the Invention

[0009] Among them, a multi-layer body having a layer containing polycarbonate resin (polycarbonate resin layer) and a layer containing acrylic resin (acrylic resin layer) sometimes needs to have flame retardancy. Moreover, such a multi-layer body also needs to have transparency.

[0010] The present invention aims to solve such a technical problem, and its object is to provide a multi-layer body with excellent flame retardancy and high transparency, and a dust cover for a head-up display using the multi-layer body.

[0011] Technical Solution for Solving the Technical Problem

[0012] The present inventors have found through research on the above technical problems that the acrylic resin layer is more flammable than the polycarbonate layer. However, even if a flame retardant is incorporated into the acrylic resin layer, it is difficult to obtain a multi-layer body that meets the Federal Motor Vehicle Safety Standards (FMVSS) of the United States. Moreover, as a result of the inventors' research, it has been found that by incorporating a specified flame retardant into the polycarbonate resin layer and reducing the thickness of the acrylic resin layer, the above technical problems can be solved.

[0013] Specifically, the above technical problems are solved by the following solutions.

[0014] <1>A multilayer body, comprising: a polycarbonate resin layer containing a polycarbonate resin and a metal sulfonate; and an acrylic resin layer having a thickness of 1 to 80 μm and containing an acrylic resin.

[0015] The content of the metal sulfonate in the above polycarbonate resin layer is 0.01 to 0.80% by mass, and the haze of the above multilayer body is 20% or less.

[0016] <2>The multilayer body according to <1>, wherein the haze of the above multilayer body is 10% or less.

[0017] <3>The multilayer body according to <1> or <2>, wherein the thickness of the above acrylic resin layer is 10 to 80 μm.

[0018] <4>The multilayer body according to any one of <1> to <3>, wherein the pencil hardness of the above multilayer body measured from the acrylic resin layer side is F or above.

[0019] <5>The multilayer body according to any one of <1> to <4>, wherein the acrylic resin layer of the above multilayer body contains a flame retardant.

[0020] <6>The multilayer body according to <1> or <2>, wherein the thickness of the above acrylic resin layer is 1 μm or more and less than 10 μm.

[0021] <7>The multilayer body according to <6>, wherein the acrylic resin layer of the above multilayer body substantially does not contain a flame retardant.

[0022] <8>The multilayer body according to any one of <1> to <7>, further having a hard coat.

[0023] <9>A dust-proof cover for a head-up display, comprising the multilayer body according to any one of <1> to <8>.

[0024] Advantages of the Invention

[0025] According to the present invention, it is possible to provide a multilayer body having excellent flame retardancy and high transparency, and a dust-proof cover for a head-up display using the multilayer body. Brief Description of the Drawings

[0026] Figure 1 It is a schematic diagram showing the layer structure of the multilayer body of the present invention. Detailed Description of the Invention

[0027] Hereinafter, specific embodiments for implementing the present invention (hereinafter simply referred to as "embodiments of the present invention") will be described in detail. It should be noted that the following embodiments of the present invention are merely illustrative examples for explaining the present invention, and the present invention is not limited to the embodiments of the present invention.

[0028] It should be noted that in this specification, "~" is used in the sense of including the values described before and after it as the lower limit value and the upper limit value.

[0029] In this specification, unless otherwise specified, all physical property values and characteristic values refer to the values at 23°C.

[0030] In this specification, unless otherwise specified, both the weight average molecular weight and the number average molecular weight are polystyrene conversion values measured by the GPC (gel permeation chromatography) method.

[0031] In this specification, "(meth)acrylate" means both acrylate and methacrylate or any one of them.

[0032] The multilayer body in this specification means products including those formed in the shape of a film or a sheet. "Film" and "sheet" respectively refer to molded products that are relatively thin and substantially flat with respect to length and width. In addition, the "film" and "sheet" in this specification can be single-layer or multi-layer.

[0033] When the measurement methods and the like described in the standards shown in this specification vary from year to year, unless otherwise specified, the standards based on the time point of January 1, 2022 are adopted.

[0034] The attached drawings of the specification are schematic diagrams, and the scale and the like may not be consistent with the actual situation.

[0035] In this specification, near-infrared light refers to light with a wavelength of 700 nm to 2500 nm.

[0036] The multilayer body of the embodiments of the present invention includes a polycarbonate resin layer containing a polycarbonate resin and a metal sulfonate, and an acrylic resin layer with a thickness of 1 to 80 μm and containing an acrylic resin. The content of the metal sulfonate in the above polycarbonate resin layer is 0.01 to 0.80% by mass, and the haze of the above multilayer body is 20% or less.

[0037] By adopting such a configuration, a multilayer body with excellent flame retardancy and high transparency can be obtained.

[0038] Acrylic resins are flammable by themselves. Even if a flame retardant is only incorporated into the acrylic resin layer, it is very difficult to achieve a flame retardancy that can pass the FMVSS test. Therefore, in the embodiment of the present invention, by incorporating a flame retardant into the polycarbonate resin layer and making the acrylic resin layer thinner, a product capable of passing the FMVSS test was formed. It should be noted that even if it fails to pass the FMVSS test, as long as the effects of the present invention can be achieved, undoubtedly, it is also included within the scope of the present invention.

[0039] In addition, once a large amount of flame retardant is incorporated into the polycarbonate resin layer, the transparency will become poor. In the embodiment of the present invention, by using a metal sulfonate as the flame retardant, flame retardancy can be exhibited with a small amount of addition, and a multilayer body with excellent transparency is obtained.

[0040] The following describes the details of the present invention.

[0041] <Polycarbonate resin layer>

[0042] The polycarbonate resin layer in the embodiment of the present invention 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.

[0043] The polycarbonate resin is not particularly limited, and various polycarbonate resins can be used as long as the molecular main chain contains a carbonate bond-containing -[O-R-OCO]- structural unit (R is a hydrocarbon group (for example, a group containing an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or both an aliphatic hydrocarbon group and an aromatic hydrocarbon group, and having a straight-chain structure or a branched-chain structure)).

[0044] In the embodiment of the present invention, the polycarbonate resin preferably contains a bisphenol-based polycarbonate resin. The bisphenol-based polycarbonate resin means that 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.

[0045] The bisphenol-based polycarbonate resin is preferably a bisphenol A-type polycarbonate resin.

[0046] The molecular weight of the polycarbonate resin is the viscosity-average molecular weight converted from the solution viscosity measured at a temperature of 25°C using dichloromethane as a solvent, and is preferably, but not particularly limited to, 20,000 or more, more preferably 22,000 or more. Additionally, the above-mentioned viscosity-average molecular weight is preferably 35,000 or less, more preferably 32,000 or less, further preferably 30,000 or less, and may also be 28,000 or less, 25,000 or less. By setting the above-mentioned viscosity-average molecular weight to be above the lower limit value, the strength of the obtained flat molded body can be improved. Furthermore, by setting the above-mentioned viscosity-average molecular weight to be below the above-mentioned upper limit value, the moldability is likely to be improved.

[0047] Among them, the viscosity-average molecular weight [Mv] refers to the intrinsic viscosity [η] (unit: dL / g) at a temperature of 25°C obtained using a Ubbelohde viscometer with dichloromethane as a solvent, and is calculated based on the Schnell viscosity formula, that is, η = 1.23×10 -4 Mv 0.83 The value calculated. Additionally, the intrinsic viscosity [η] refers to the value calculated by measuring the specific viscosity [η sp at each solution concentration [C] (g / dL) and calculating according to the following formula.

[0048] [Mathematical formula 1]

[0049]

[0050] It should be noted that in the embodiments of the present invention, two or more polycarbonate resins with different viscosity-average molecular weights can be mixed and used, and in this case, the viscosity-average molecular weight of the mixture is adopted.

[0051] The initial glass transition temperature (Tg) of the polycarbonate resin used in the embodiments of the present invention is preferably 160°C or less, more preferably 155°C or less, further preferably 154°C or less, still further preferably 153°C or less, yet further preferably 152°C or less, and even further preferably 151°C or less, and can be 150°C or less, 149°C or less. Additionally, the initial glass transition temperature (Tg) of the polycarbonate resin used in the embodiments of the present invention is, for example, 140°C or more, and can also be 143°C or more, 145°C or more, 147°C or more, 148°C or more.

[0052] The glass transition temperature is measured according to the description in paragraph

[0056] of Japanese Patent Laid-Open No. 2022-080270.

[0053] In addition, for the details of the polycarbonate resin, reference can also be made to the descriptions in paragraphs

[0011] to

[0020] of Japanese Patent Laid-Open No. 2012-144604 and paragraphs

[0014] to

[0035] of Japanese Patent Laid-Open No. 2019-002023, and these contents are incorporated into this specification.

[0054] In the polycarbonate resin layer of the embodiment of the present invention, the content of the polycarbonate resin is preferably 90% by mass or more, more preferably 92% by mass or more, further preferably 94% by mass or more, still further preferably 96% by mass or more, and even further preferably 97% by mass or more, and may be 98% by mass or more, based on 100% by mass of the polycarbonate resin layer. The upper limit is the amount of components other than the metal sulfonate in the polycarbonate resin layer that becomes the polycarbonate resin.

[0055] When the polycarbonate resin layer in the embodiment of the present invention contains two or more polycarbonate resins, it is preferable that the total amount is within the above range.

[0056] The polycarbonate resin layer in the embodiment of the present invention contains a metal sulfonate. The metal sulfonate is generally a component used as a flame retardant in the polycarbonate resin.

[0057] The metal sulfonate is preferably an alkali metal salt. As the alkali metal constituting the alkali metal salt, lithium, sodium, potassium, and rubidium are preferred, and sodium and potassium are more preferred. In addition, the metal sulfonate may contain fluorine atoms.

[0058] The molecular weight of the metal sulfonate used in the embodiment of the present invention is preferably 100 to 900, more preferably 100 to 500.

[0059] Specific examples of the metal sulfonate used in the embodiment of the present invention are shown below. Needless to say, in the embodiment of the present invention, the metal sulfonate is not limited thereto.

[0060]

[0061] 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, further preferably 0.5% by mass or less, still further preferably 0.4% by mass or less, and depending on the use and the like, it may also be less than 0.1% by mass or 0.05% by mass or less. By using the metal sulfonate, even when the amount of the flame retardant compounded in the polycarbonate resin layer is reduced, excellent flame retardancy can still be achieved, and a multilayer body with excellent transparency and heat and humidity resistance can be obtained.

[0062] The polycarbonate resin layer in the embodiment of the present invention may contain only one metal sulfonate or may contain two or more. When two or more are contained, it is preferable that the total amount is within the above range.

[0063] In the polycarbonate resin layer of the embodiment of the present invention, a flame retardant other than metal sulfonate may or may not be contained. Examples of the flame retardant other than metal sulfonate include a phosphorus-based flame retardant, a halogen-based flame retardant, etc. As an example of the polycarbonate resin layer in the embodiment of the present invention, a mode in which a metal sulfonate and a phosphorus-based flame retardant are used in combination can be cited.

[0064] The polycarbonate resin layer in the embodiment of the present invention preferably substantially does not contain a flame retardant other than metal sulfonate. Substantially not containing means that the content of the flame retardant other than metal sulfonate is 50% by mass or less, preferably 10% by mass or less, more preferably 3% by mass or less, and further preferably 1% by mass or less of the total amount of the flame retardants contained in the polycarbonate resin layer.

[0065] In addition to the above components, the polycarbonate resin layer of the embodiment of the present invention may further contain an antioxidant, a release agent, an ultraviolet absorber, a flame retardant aid, a heat stabilizer, a colorant, an antistatic agent, a fluorescent brightening agent, an antifogging agent, a fluidity improver, a plasticizer, a dispersant, an antibacterial agent, an anti-blocking agent, an impact resistance improver, a sliding property improver, a hue improver, an acid scavenger, etc. One of these components can be used, or two or more can be used in combination. The content of the above components is preferably 0 to 5% by mass, more preferably 0 to 3% by mass, further preferably 0 to 1% by mass, still further preferably 0 to 0.5% by mass, yet further preferably 0 to 0.3% by mass, and still further preferably 0 to 0.1% by mass of the polycarbonate resin layer in total.

[0066] Examples of the antioxidant include a phenolic antioxidant, an amine-based antioxidant, a phosphorus-based antioxidant, a thioether-based antioxidant, etc. Among them, in the embodiment of the present invention, a phosphorus-based antioxidant and a phenolic antioxidant (more preferably a hindered phenolic antioxidant) are preferred, and a phosphorus-based antioxidant is more preferred.

[0067] The phosphorus-based antioxidant is preferably a phosphite-based antioxidant, and preferably a phosphite compound represented by the following formula (1) or (2).

[0068]

[0069] In formula (1), R 11 and R 12 each independently represent an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms.

[0070]

[0071] In formula (2), R 13 to R 17Each independently represents a hydrogen atom, an aryl group having 6 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms.

[0072] In the above formula (1), R 11 , R 12 The alkyl groups represented are preferably each independently a straight-chain or branched-chain alkyl group having 1 to 10 carbon atoms. When R 11 , R 12 is an aryl group, it is preferably an aryl group represented by any one of the following formulas (1-a), (1-b), and (1-c). "*" in the formula represents the bonding position.

[0073]

[0074] In formula (1-a), R A each independently represents an alkyl group having 1 to 10 carbon atoms. In formula (1-b), R B each independently represents an alkyl group having 1 to 10 carbon atoms.

[0075] As the hindered phenol antioxidant, reference can be made to the descriptions in paragraphs

[0063] of Japanese Patent Application Laid-Open No. 2018-090677 and paragraphs

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

[0076] In addition to the above compounds, for the antioxidant, reference can be made to the descriptions in paragraphs

[0057] to

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

[0077] The content of the antioxidant relative to 100 parts by mass of the polycarbonate resin layer is preferably 0.001 part by mass or more, more preferably 0.005 part by mass or more, further preferably 0.010 part by mass or more, still further preferably 0.050 part by mass or more. In addition, as the upper limit value of the antioxidant content, relative to 100 parts by mass of the polycarbonate resin layer, it is preferably 0.500 part by mass or less, more preferably 0.300 part by mass or less, further preferably 0.200 part by mass or less, still further preferably 0.150 part by mass or less, still further preferably 0.100 part by mass or less, particularly more preferably 0.080 part by mass or less.

[0078] The antioxidant can be used alone or in combination of two or more. When two or more are used, it is preferably that the total amount is within the above range.

[0079] Next, the mold release agent that can be contained in the polycarbonate resin layer will be described.

[0080] Examples of the release agent include, but are not particularly limited to, for example, aliphatic carboxylic acids, esters formed from aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15,000, polyethers having a number average molecular weight of 100 to 5,000, polysiloxane-based silicone oils, and the like.

[0081] Details of the release agent can be referred to the description in paragraphs

[0035] to

[0039] of International Publication No. 2015 / 190162, the content of which is incorporated into this specification.

[0082] The content of the release agent relative to 100 parts by mass of the polycarbonate resin layer is preferably 0.001 part by mass or more, more preferably 0.005 part by mass or more, further preferably 0.010 part by mass or more, and still further preferably 0.050 part by mass or more. As the upper limit value, it is preferably 0.5 part by mass or less, more preferably 0.3 part by mass or less, and further preferably 0.1 part by mass or less.

[0083] Only one type of release agent may be used, or two or more types may be used. In the case of using two or more types, it is preferable that the total amount thereof is within the above range.

[0084] The thickness of the polycarbonate resin layer is preferably 50 μm or more, more preferably 100 μm or more, and still further preferably 200 μm or more. By setting it above the above lower limit value, not only the molding becomes easier, but also the flame retardancy tends to be improved. In addition, the upper limit of the thickness of the polycarbonate resin layer is preferably 1000 μm or less, more preferably 750 μm or less, and further preferably 500 μm or less.

[0085] <Acrylic resin layer>

[0086] In the embodiment of the present invention, the thickness of the acrylic resin layer is 1 to 80 μm and contains an acrylic resin.

[0087] The thickness of the acrylic resin layer is preferably 1 μm or more, more preferably 3 μm or more, further preferably 10 μm or more, still further preferably 20 μm or more, even further preferably 25 μm or more, and yet further preferably 30 μm or more. By setting it above the above lower limit value, not only the molding becomes easier, but also the hardness tends to be improved. In addition, 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, 40 μm or less. Depending on the use and the like, it may also be less than 10 μm. By setting the thickness of the acrylic resin layer so thin, the flame retardancy of the multilayer body can be improved.

[0088] In addition, the acrylic resin layer may be a single layer or multiple layers, and a single layer is preferred.

[0089] The acrylic resin layer of the embodiment of the present invention contains an acrylic resin as described above.

[0090] One example of the acrylic resin is preferably a polymer in which the content of (meth)acrylic acid alkyl ester units (preferably methacrylic acid alkyl ester units, or preferably (meth)acrylic acid alkyl ester units having 1 to 3 carbon atoms in the alkyl group, more preferably methacrylic acid alkyl ester units having 1 to 3 carbon atoms in the alkyl group) in all structural units is 50% by mass or more (preferably 90% by mass or more, more preferably 95% by mass or more), and more preferably a polymer in which the content of (meth)acrylic acid methyl ester units (preferably methacrylic acid methyl ester units) in all structural units is 50% by mass or more (preferably 90% by mass or more). Examples of structural units other than (meth)acrylic acid alkyl ester units include other (meth)acrylic acid ester units, styrene units, cyclic acid anhydride units, N-substituted maleimide units, and lactone ring units.

[0091] In the case where the acrylic resin layer of the embodiment of the present invention is multilayer (in the case of being composed of two or more layers), it is preferable that all acrylic resin layers contain the above acrylic resin.

[0092] The acrylic resin layer may be formed only of an acrylic resin, or may contain other thermoplastic resins in addition to the acrylic resin.

[0093] As other thermoplastic resins, it is more preferable to contain at least one thermoplastic resin selected from styrene resins, fluororesins such as polyvinylidene fluoride, and aromatic polyether resins such as polyphenylene ether, and it is further preferable to contain styrene resins.

[0094] One example of the acrylic resin layer is a layer in which 90% by mass or more (preferably 95% by mass or more, more preferably 97% by mass or more, further preferably 98% by mass or more) is composed of an acrylic resin.

[0095] Another example of the acrylic resin layer is a layer in which 90% by mass or more (preferably 95% by mass or more, more preferably 97% by mass or more, further preferably 98% by mass or more) is composed of the above acrylic resin and other thermoplastic resins (preferably styrene resins).

[0096] The weight average molecular weight of the acrylic resin is preferably 10,000 or more, more preferably 30,000 or more, further preferably 50,000 or more, still further preferably 60,000 or more, and even further preferably 70,000 or more, although not particularly limited. In addition, the weight average molecular weight of the acrylic resin is preferably 250,000 or less, more preferably 200,000 or less, further preferably 150,000 or less, still further preferably 100,000 or less, and even further preferably 90,000 or less.

[0097] The glass transition temperature of the acrylic resin layer used in the embodiments of the present invention is preferably 80 °C or higher, more preferably 90 °C or higher, further preferably 95 °C or higher, still further preferably 100 °C or higher, and even further preferably 105 °C or higher. The upper limit is not particularly limited, but in practical applications, it is, for example, 200 °C or lower.

[0098] The glass transition temperature is measured according to the description in paragraph

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

[0099] In addition to the above components, the acrylic resin layer may contain inorganic particles, antioxidants, mold release agents, ultraviolet absorbers, heat stabilizers, flame retardants, flame retardant aids, colorants, antistatic agents, fluorescent brighteners, antifogging agents, fluidity improvers, plasticizers, dispersants, antibacterial agents, anti-blocking agents, impact resistance improvers, sliding property improvers, hue improvers, acid scavengers, etc. These components may be used singly or in combination of two or more. When the above components are contained, the content of the above components is preferably 0.1 to 5% by mass of the acrylic resin layer in total.

[0100] As described above, the acrylic resin layer of the embodiments of the present invention may contain a flame retardant. Examples of the flame retardant that can be contained in the acrylic resin layer include phosphorus-based flame retardants.

[0101] Examples of the phosphorus-based flame retardants include aromatic phosphate compounds, phosphaphenanthrene compounds, metal hypophosphites, ammonium polyphosphate, melamine polyphosphate, phosphate amides, and red phosphorus, etc. Aromatic phosphate compounds and phosphaphenanthrene compounds are preferred.

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

[0103] The phosphaphenanthrene compound is a phosphorus-based flame retardant having at least one phosphaphenanthrene skeleton in the molecule. Examples of commercially available products thereof include HCA, HCA-HQ, BCA, SANKO-220, and M-Ester manufactured by Mitsuwa Chemical Co., Ltd.

[0104] The metal hypophosphite is a hypophosphite and / or a secondary phosphite and / or a polymer thereof. Examples of the above salts include salts of calcium, aluminum, and zinc, etc. Examples of commercially available products of the metal hypophosphite include Exolit of Clariant Japan TMOP1230, Exolit TM OP1240, etc.

[0105] Phosphate ester amide is an aromatic amide-based flame retardant containing phosphorus atoms and nitrogen atoms. As a commercially available product of phosphate ester amide, it is preferably SP-703 manufactured by Shikoku Kasei Co., Ltd., etc.

[0106] As ammonium polyphosphate, ammonium polyphosphate, melamine-modified ammonium polyphosphate, carbamoyl ammonium polyphosphate, etc. can be cited. As the above-mentioned melamine polyphosphate, melamine phosphate, pyrophosphate melamine, and phosphates formed with melamine, melem, and melam can be cited. It is preferably MPP-A manufactured by Sanwa Chemical Co., Ltd., PMP-100, PMP-200, etc. manufactured by Nissan Chemical Industries, Ltd.

[0107] When the acrylic resin layer contains a flame retardant, its content relative to 100 parts by mass of the acrylic resin layer is preferably 1 part by mass or more, more preferably 2 parts by mass or more, further preferably 5 parts by mass or more, and still further preferably 7 parts by mass or more. In addition, the upper limit value of the content of the above-mentioned flame retardant relative to 100 parts by mass of the acrylic resin layer is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 15 parts by mass or less.

[0108] The acrylic resin layer may contain only one kind of flame retardant or may contain two or more kinds. When two or more kinds are contained, it is preferably within the above range in total amount.

[0109] In addition, the multilayer body of the present embodiment may also adopt a configuration in which the acrylic resin layer substantially does not contain a flame retardant. Substantially not containing means that the content of the flame retardant in the acrylic resin layer is less than 1 part by mass relative to 100 parts by mass of the acrylic resin layer, preferably 0.1 part by mass or less, and more preferably 0.01 part by mass or less. In the embodiment of the present invention, even if the flame retardant is not substantially incorporated in the flammable acrylic resin layer, flame retardancy can be achieved, which is thus of great value. In addition, when the content of the flame retardant in the acrylic resin layer is small, roll contamination (roll scale) during manufacturing can be effectively suppressed.

[0110] In addition, when the thickness of the acrylic resin layer is, for example, less than 20 μm, further less than 10 μm, and particularly 8 μm or less, it is preferable to adopt a configuration in which the acrylic resin layer substantially does not contain a flame retardant.

[0111] <Multilayer body>

[0112] As described above, the multilayer body of the embodiment of the present invention has a polycarbonate resin layer and an acrylic resin layer.

[0113] The thickness (total thickness) of the multilayer body is preferably, but not particularly limited to, 30 μm or more, more preferably 100 μm or more. In addition, the thickness of the multilayer body is preferably 10000 μm or less, more preferably 5000 μm or less, still more preferably 2000 μm or less, and may be 1000 μm or less, 500 μm or less.

[0114] The multilayer body according to the embodiment of the present invention preferably has a high (hard) pencil hardness. The pencil hardness measured from the acrylic resin layer side is preferably F or more, more preferably H or more. In addition, although the upper limit is not particularly limited, it is 3H or less in practical applications.

[0115] The multilayer body of the present embodiment preferably also has excellent transparency. Specifically, the haze of the multilayer body is 20% or less, preferably 10% or less, more preferably 5% or less, still more preferably 3% or less, even more preferably 2% or less, yet more preferably 1.5% or less, still more preferably 1% or less, particularly preferably 0.8% or less, and may also be 0.5% or less. Although the lower limit value is preferably 0% or more, it is higher than 0% in practical applications.

[0116] The multilayer body according to the embodiment of the present invention preferably also has excellent flame retardancy. Specifically, the multilayer body preferably satisfies the C-level rating in the FMVSS test (although it burns until before reaching the B marking line, but the burning speed is 102 mm / min or less), more preferably satisfies the B-level rating in the FMVSS test (self-extinguishes when the burning distance is within 51 mm from the A marking line (and within 60 seconds)), and still more preferably satisfies the A-level rating (the test piece does not burn or self-extinguishes just before reaching the A marking line).

[0117] The pencil hardness, haze, and FMVSS test are measured according to the description in the following examples.

[0118] The multilayer body according to the embodiment of the present invention may also further include a hard coat. Preferably, a hard coat is provided on at least one surface of the multilayer body. The hard coat may be the outermost layer of the multilayer body. By providing the hard coat, the surface hardness of the multilayer body can often be further improved. In the multilayer body according to the embodiment of the present invention, the hard coat is preferably laminated in the order of a polycarbonate resin layer, an acrylic resin layer, and a hard coat. In the multilayer body according to the embodiment of the present invention, the hard coat is preferably provided on the surface of the acrylic resin layer. By providing the hard coat on the surface of the acrylic resin layer, the coating performance of the hard coat can be further improved.

[0119] Figure 1The figure is a schematic diagram showing an example of a multilayer body according to an embodiment of the present invention. As described above, 1 represents the multilayer body, 2 represents a polycarbonate resin layer, 3 represents an acrylic resin layer, and 4 represents a hard coat. The polycarbonate resin layer 2, the acrylic resin layer 3, and the hard coat 4 may be laminated in the above order, and other layers may be provided therebetween within the scope not departing from the gist of the embodiment of the present invention, but it is preferably that there are no other layers, that is, it is preferably that the three are in adjacent contact with each other.

[0120] The hard coat that can be included in the multilayer body according to the embodiment of the present invention is a layer having a surface hardness higher than that of the polycarbonate resin layer. By including such a hard coat, the surface hardness of the multilayer body or the molded article can be improved. In addition, by including a hard coat having a higher surface hardness, the flame retardancy tends to be further improved.

[0121] The thickness of the hard coat is preferably 0.5 μm or more, more preferably 1 μm or more, further preferably 2 μm or more, still further preferably 2.5 μm or more, and even further preferably 3 μm or more. By setting it above the above lower limit value, the pencil hardness of the entire multilayer body can often be further improved by the hard coat. The upper limit of the thickness of the hard coat is preferably 20 μm or less, more preferably 15 μm or less, further preferably 12 μm or less, still further preferably 10 μm or less, and even further preferably 8 μm or less, and may be 5 μm or less. By setting it below the above upper limit value, the flame retardancy can often be further improved.

[0122] The hard coat is preferably a layer obtained by applying a hard coat material that can be cured by heat or by active energy rays and then curing it.

[0123] As an example of a coating material that is cured by active energy rays, a resin composition composed of a single kind or a plurality of monofunctional or polyfunctional (preferably 2 to 10 functional) (meth)acrylate monomers or oligomers, etc. can be cited, and a resin composition containing a monofunctional or polyfunctional (preferably 2 to 10 functional) polyurethane (meth)acrylate oligomer is preferably selected. In these resin compositions, a photopolymerization initiator is preferably added as a curing catalyst.

[0124] In addition, as a thermosetting resin coating, polyorganosiloxane-based, crosslinked acrylic-based coatings, etc. can be cited. There are also commercially available products of such resin compositions as hard coat coating agents for films or sheets of acrylic resins or polycarbonate resins, and they can be appropriately selected according to the compatibility with the coating production line.

[0125] As the hard coat, reference can be made to the descriptions in paragraphs

[0045] to

[0055] of Japanese Patent Application Laid-Open No. 2013-020130, paragraphs

[0073] to

[0076] of Japanese Patent Application Laid-Open No. 2018-103518, and paragraphs

[0062] to

[0082] of Japanese Patent Application Laid-Open No. 2017-213771, the contents of which are incorporated herein.

[0126] In addition to the above components, the hard coat may further contain inorganic particles, organic pigments, ultraviolet absorbers, light stabilizers, heat stabilizers, flame retardants, flame retardant aids, colorants, antistatic agents, fluorescent brighteners, antifogging agents, fluidity improvers, plasticizers, dispersants, antibacterial agents, anti-blocking agents, impact resistance improvers, sliding property improvers, hue improvers, acid scavengers, etc. These components may be used singly or in combination of two or more.

[0127] As the inorganic particles, preferably, nanoparticles containing a metal and / or a metal compound can be mentioned. For example, gold, silver, copper, platinum, palladium, nickel, cobalt, iron, manganese, silicon, titanium, zirconium, tungsten, molybdenum, chromium, zinc, aluminum, and composite metals composed of two or more of them can be mentioned. In addition, as the metal compound, preferably, metal oxides such as iron oxide, silicon oxide, zirconium oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, cobalt oxide, nickel oxide, cerium oxide, copper oxide, zinc oxide, tin oxide, antimony oxide, titanium dioxide, aluminum oxide, indium tin oxide (ITO), cesium tungsten oxide (CWO), and mixtures thereof, metal carbides, metal borides, metal carbonates, zeolites, clays, and their composites can be mentioned.

[0128] As examples of the flame retardant, halogen-based flame retardants and phosphorus-based flame retardants can be exemplified. As the phosphorus-based flame retardants, aromatic phosphate compounds, phosphaphenanthrene compounds, metal hypophosphites, ammonium polyphosphate, melamine polyphosphate, phosphate ester amides, and red phosphorus can be mentioned. As the flame retardant, reference can be made to the descriptions in paragraphs

[0054] to

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

[0052] to

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

[0129] The multilayer body of the embodiment of the present invention may also have a near-infrared cut-off layer. The near-infrared cut-off layer is preferably a layer containing a near-infrared absorber. As an example of the infrared cut-off layer, a mode in which a near-infrared absorber (for example, cesium tungsten oxide (CWO)) is incorporated into the hard coat can be exemplified. Since the hard coat contains a near-infrared absorber, the multilayer body can cut off near-infrared rays and can be more preferably used as a dust cover for a head-up display.

[0130] In addition to the above layers, the multilayer body according to the embodiment of the present invention may further have other layers. Specific examples include a bonding layer, an adhesive layer, an antifouling layer, etc.

[0131] Moreover, the multilayer body may be subjected to any one or more of fingerprint resistance treatment, antiglare treatment, weather resistance treatment, antistatic treatment, antifouling treatment, and antiadhesion treatment on at least one of its surfaces. As an example of the outermost surface of the multilayer body in this case, a hard coat can be cited. In addition, the antiadhesion treatment refers to a treatment that enables easy peeling even when the films are in close contact with each other, and examples include adding an antiadhesion agent and providing irregularities on the surface of the multilayer body.

[0132] The multilayer body according to the embodiment of the present invention can be formed by using a main extruder for extruding a polycarbonate resin layer-forming composition and an auxiliary extruder for extruding an acrylic resin layer-forming composition, melting and extruding the resins according to the conditions of each resin used, introducing them into a die, laminating them inside the die and forming them into a sheet, or laminating them after forming them into a sheet.

[0133] The multilayer body according to the embodiment of the present invention can be used directly, or can be formed into a molded product through processing, particularly through heat processing.

[0134] The molded product according to the embodiment of the present invention is a molded product formed from the multilayer body according to the embodiment of the present invention.

[0135] <Use>

[0136] The multilayer body or molded product according to the embodiment of the present invention can be applied to optical components, design products, antireflection molded bodies, etc.

[0137] The multilayer body according to the embodiment of the present invention can be applied to components of display devices, electrical and electronic devices, OA (office automation) devices, portable information terminals, mechanical components, household appliances, vehicle components, various containers, lighting devices, etc. Among them, it is particularly applicable to housings of various displays, electrical and electronic devices, OA devices, portable information terminals, and household appliances, lighting devices and vehicle components (especially automotive interior components), surface films of smartphones and touchscreens, optical materials, and optical discs. The multilayer body according to the embodiment of the present invention is particularly preferably used as a dust cover for a head-up display.

[0138] Examples

[0139] The following examples illustrate the present invention more specifically. The materials, amounts used, ratios, treatment contents, treatment steps, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[0140] When it is difficult to obtain the measuring instruments and the like used in the examples due to production suspension or other reasons, other devices with equivalent performance can be used for measurement.

[0141] 1. Raw materials

[0142] Polycarbonate resin

[0143] E-2000F: A polycarbonate resin obtained by an interfacial polymerization method using bisphenol A as a starting material (E-2000F manufactured by Mitsubishi Gas Chemical Company, Limited, viscosity-average molecular weight: 27,000, Tg: 150 °C)

[0144] S-3000F: A polycarbonate resin obtained by an interfacial polymerization method using bisphenol A as a starting material (S-3000F manufactured by Mitsubishi Gas Chemical Company, Limited, viscosity-average molecular weight: 21,000, Tg: 147 °C).

[0145] Metal sulfonate

[0146] KSS-FR: Manufactured by Arichem Corporation, KSS-FR, potassium diphenyl sulfone-3-sulfonate

[0147] NATS: Manufactured by Tokyo Chemical Industry Co., Ltd., NATS, sodium p-toluenesulfonate

[0148] F-114P: Manufactured by DIC Corporation, F-114P, potassium perfluorobutanesulfonate.

[0149] Phosphorus-based flame retardant

[0150] PX-200: The following compound manufactured by Daihachi Chemical Industry Co., Ltd.

[0151]

[0152] Antioxidant

[0153] 2112: Tris(2,4-di-tert-butylphenyl) phosphite (phosphorus-based antioxidant, Adekastab 2112 manufactured by ADEKA Corporation)

[0154] Release agent

[0155] S-100A: Glycerol monostearate (RIKEMAL S-100A manufactured by Riken Vitamin Co., Ltd.)

[0156] Acrylic resin

[0157] PMMA: Polymethyl methacrylate, manufactured by Asahi Kasei Corporation, DELPET 80HD.

[0158] Flame retardant

[0159] BCA: manufactured by Mitsuho Corporation, the following compound

[0160]

[0161] 2. Examples 1 to 10, Comparative Examples 1 to 10

[0162] <Manufacture of Resin Composition (Pellets)>

[0163] The resin composition (pellets) for forming a polycarbonate resin layer and the resin composition (pellets) for forming an acrylic resin layer were manufactured according to the following method.

[0164] Each of the above components was weighed according to the addition amounts described in Table 1 or Table 2 (each component in Table 1 and Table 2 is expressed in mass %). Then, after mixing for 15 minutes with a tumbler, it was melt-kneaded using a vented twin-screw extruder with a screw diameter of 32 mm ("TEX30α" manufactured by Japan Steel Works, Ltd.), and the strands were cut to obtain pellets. It should be noted that the resin composition (pellets) for forming a polycarbonate resin layer was melt-kneaded under the condition of appropriately changing the temperature at a temperature of 260 to 300 °C according to the resin viscosity, and the resin composition (pellets) for forming an acrylic resin layer was melt-kneaded at a temperature of 260 °C.

[0165] <Manufacture of Multilayer Body>

[0166] A multilayer extrusion device having a single-screw extruder with a screw diameter of 32 mm, a single-screw extruder with a screw diameter of 65 mm, a feed unit connected to all extruders, and a 650-mm-wide T-die connected to the feed unit was used to form a multilayer body. The resin composition (pellets) used for forming the acrylic resin layer in each of the examples and comparative examples shown in Table 1 and Table 2 was introduced into a single-screw extruder with a screw diameter of 32 mm and extruded under the conditions of a barrel temperature of 240 °C and a discharge rate of 0.3 to 6.4 kg / h. And the resin composition (pellets) used for forming the polycarbonate resin layer in each of the examples and comparative examples shown in Table 1 and Table 2 was continuously introduced into a single-screw extruder with a screw diameter of 65 mm, and extruded at a discharge rate of 17.4 to 23.5 kg / h under the condition of appropriately changing the barrel temperature in the range of 250 to 290 °C according to the resin viscosity. The feed unit connected to all extruders has two double-layer distribution pins, and extrusion and lamination were performed. It was extruded into a sheet shape using a T-die connected to the end of the extruder, and mirror transfer was performed using three mirror-polished rolls with temperatures of 120 °C, 120 °C, and 140 °C from the upstream side, and cooled simultaneously to obtain each multilayer body.

[0167] In addition, it was visually confirmed whether there was roll fouling on the rolls used in the production. During the confirmation process, five experts conducted evaluations and made judgments by the method of the minority obeying the majority. The judgment results are shown as "roll fouling" in the following table.

[0168] <Pencil hardness>

[0169] In accordance with JIS K5600-5-4:1999, using a pencil hardness tester, the surface on the side of the acrylic resin layer of the multilayer body prepared as described above was measured under a load of 750 g, and the pencil hardness was obtained. The evaluation was made by five experts by the method of the minority obeying the majority.

[0170] <FMVSS test>

[0171] For the multilayer body obtained above, using an FMVSS No. 302 flammability test device, starting from the right end of the test piece (350 mm × 100 mm × 0.375 mm), it was brought into contact with a 38-mm burner flame for 15 seconds, and the burning rate for a burning distance of 254 mm between the marking lines was measured. The test fixture was measured without a heat-resistant metal support wire (wire), and the evaluation was carried out as described below.

[0172] A: The test piece is non-flammable or self-extinguishes before reaching the A marking line.

[0173] B: Self-extinguishes when the burning distance is within 51 mm from the A marking line (and within 60 seconds).

[0174] C: Although it burns continuously until before reaching the B marking line, the burning rate is 102 mm / min or less.

[0175] D: Burns continuously until before reaching the B marking line, and the burning rate is faster than 102 mm / min.

[0176] <Haze>

[0177] The haze (unit: %) of the obtained multilayer body was measured under the conditions of a D65 light source and a 10° field of view.

[0178] During the measurement, a haze meter ("HM-150" manufactured by Murakami Color Technology Research Institute) was used.

[0179] Comparative Example 11

[0180] <Manufacture of resin composition (pellets)>

[0181] A resin composition (pellets) for forming a polycarbonate resin layer was manufactured in the same manner as in Example 1.

[0182] <Manufacture of multilayer body>

[0183] A T-die melt extruder equipped with a vented twin-screw extruder TEX30α (manufactured by Japan Steel Works, Ltd.) having a barrel diameter of 32 mm and an L / D of the screw of 31.5 was used. Under the condition of a barrel temperature of 280 °C, the resin composition (pellets) used to form the polycarbonate resin layer was continuously introduced and extruded. During this process, the discharge amount of the above pellets was controlled so that the thickness of the polycarbonate layer reached 375 μm. It was extruded into a sheet shape using a T-die connected to the extruder, and mirror transfer was performed using three mirror-polished rollers with temperatures of 120 °C, 120 °C, and 140 °C from the upstream side, while cooling was carried out to obtain a multilayer body.

[0184] The obtained multilayer body was evaluated in the same manner as in Example 1.

[0185] [Table 1]

[0186]

[0187] [Table 2]

[0188]

[0189] Examples 11 to 13

[0190] [Preparation of Hard Coating Liquid A]

[0191] 96 parts by mass of NOPCOCURE FC950 (urethane acrylate, solid content concentration 50% by mass, manufactured by SANNOPCO), 2 parts by mass of Esacure One (photoinitiator, 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) were mixed, and then diluted with propylene glycol monoethyl ether to a solid content concentration of 25% by mass to obtain a mixed liquid.

[0192] [Preparation of Hard Coating Liquid B]

[0193] 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 liquid.

[0194] [Formation of Hard Coating]

[0195] According to the above-mentioned Example 1, a multilayer body as shown in Table 3 was fabricated. On the side of the acrylic resin layer of the multilayer body, the mixed solution obtained by the preparation of the above-mentioned hard coat coating liquid was coated with a bar coater so that the dry film thickness became 3 μm, and drying was performed at a temperature of 80 °C for 2 minutes using an oven. Then, using an ultraviolet irradiation device manufactured by Heraeus, ultraviolet curing was performed in a nitrogen atmosphere so that the cumulative light amount reached 200 mJ, and a multilayer body was obtained. At this time, the film thickness of the hard coat was 3 μm.

[0196] The FMVSS test, pencil hardness, and haze were measured in the same manner as in Example 1. The pencil hardness was measured on the side provided with the hard coat.

[0197] <Appearance of the hard coat>

[0198] The appearance of the film after coating the hard coat was evaluated for defects. The appearance defects of the hard coat were observed with the naked eye. During the confirmation process, five experts conducted the evaluation, and the judgment was made by the method of the minority obeying the majority and evaluated as follows.

[0199] A: No appearance defects

[0200] B: There are appearance defects

[0201] Comparative Example 12

[0202] <Formation of the hard coat>

[0203] According to the above-mentioned Comparative Example 11, a multilayer body as shown in Table 3 was fabricated. On the surface of the polycarbonate resin layer, the mixed solution obtained by the preparation of the above-mentioned hard coat coating liquid was coated with a bar coater so that the dry film thickness became 3 μm, and drying was performed at a temperature of 80 °C for 2 minutes using an oven. Then, using an ultraviolet irradiation device manufactured by Heraeus, ultraviolet curing was performed in a nitrogen atmosphere so that the cumulative light amount reached 200 mJ, and a multilayer body was obtained. At this time, the film thickness of the hard coat was 3 μm.

[0204] The obtained multilayer body was evaluated in the same manner as in Example 11.

[0205] [Table 3]

[0206]

[0207] Example 14

[0208] Except for the changes shown in Table 4, it was carried out in the same manner as in Example 1.

[0209] Example 15

[0210] Except for the changes shown in Table 4, it was carried out in the same manner as in Example 13.

[0211] [Table 4]

[0212]

[0213] In the above Tables 1 to 4, the PC layer refers to the polycarbonate resin layer, and in Tables 3 and 4, the HC layer refers to the hard coat.

[0214] It is clearly understood from the above results that the multilayer body of the embodiment of the present invention has excellent flame retardancy and excellent transparency. Moreover, the pencil hardness is also very high.

[0215] Symbol Explanation

[0216] 1: Multilayer body

[0217] 2: Polycarbonate resin layer

[0218] 3: Acrylic resin layer

[0219] 4: Hard coat.

Claims

1. A multilayer body, characterized in that: the multilayer body comprises: a polycarbonate resin layer containing a polycarbonate resin and a metal sulfonate; and an acrylic resin layer having a thickness of 1 to 80 μm and containing an acrylic resin, the content of the metal sulfonate in the polycarbonate resin layer is 0.01 to 0.80% by mass, and the haze of the multilayer body is 20% or less.

2. The multilayer body according to claim 1, characterized in that: the haze of the multilayer body is 10% or less.

3. The multilayer body according to claim 1 or 2, characterized in that: the thickness of the acrylic resin layer is 10 to 80 μm.

4. The multilayer body according to any one of claims 1 to 3, characterized in that: the pencil hardness of the multilayer body measured from the acrylic resin layer side is F or above.

5. The multilayer body according to any one of claims 1 to 4, characterized in that: the acrylic resin layer of the multilayer body contains a flame retardant.

6. The multilayer body according to claim 1 or 2, characterized in that: the thickness of the acrylic resin layer is 1 μm or more and less than 10 μm.

7. The multilayer body according to claim 6, characterized in that: the acrylic resin layer of the multilayer body substantially does not contain a flame retardant.

8. The multilayer body according to any one of claims 1 to 7, characterized in that: the multilayer body further has a hard coat.

9. A dust-proof cover for a head-up display, characterized in that: it comprises the multilayer body according to any one of claims 1 to 8.

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