Resin composition, flat molded body, multilayer body, molded article, and method for producing molded article

Abstract

A resin composition which makes it possible to provide a laminate in which the occurrence of cracking is suppressed and flow marks are not prone to occur is provided; a plate-shape molded body, a laminate and a molded product that use the resin composition are also provided. This resin composition contains a resin that contains (meth)acrylic compound units and aromatic vinyl compound units; in the resin composition, the total of the (meth)acrylic compound units and aromatic vinyl compound units is greater than or equal to 55 mass%, the initial glass transition temperature (Tig) of the resin composition measured by differential scanning calorimetry is greater than or equal to 135°C, the un-notched Charpy impact strength when forming the resin composition into a 3 mm-thick ISO test piece is greater than or equal to 10.0 kJ / m2, the un-notched Charpy impact strength is the value obtained by changing the thickness of the ISO test piece from 4 mm to 3 mm and otherwise measuring in the same manner as JIS K 7111-1; the melt viscosity of the resin composition at 240°C and at a shear velocity 1220 s-1 is less than or equal to 500 Pa*s.

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a flat molded article, a multi-layered body, a molded article, and a method for producing the molded article. [Background technology]

[0002] Acrylic resins have excellent transparency, moldability, and surface hardness, and are therefore used in a wide range of applications as optical materials. For example, Patent Document 1 discloses a resin composition comprising 10 to 70 parts by mass of the following (meth)acrylic acid ester polymer (A) and 90 to 30 parts by mass of a styrene-maleic anhydride copolymer (B), and characterized in that the haze at a thickness of 2 mm measured according to ASTM D1003 is 3% or less. (Meth)acrylic acid ester polymer (A): a polymer consisting of 60 to 100% by mass of (meth)acrylic acid ester monomer units and 40 to 0% by mass of styrene monomer units Styrene-maleic anhydride copolymer (B): A copolymer consisting of 75 to 95% by mass of styrene monomer units and 25 to 5% by mass of maleic anhydride. On the other hand, since acrylic resin has poor material toughness, multilayer films and sheets are produced by co-extrusion with polycarbonate resin, which has excellent transparency and material toughness. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-050536 Summary of the Invention [Problem to be solved by the invention]

[0004] It was found that when a layer containing an acrylic resin and a layer containing a polycarbonate resin are combined to form a multilayer body and molded into a desired shape, cracks and flow marks may occur, particularly when molded at a high temperature of about 135°C. The present invention aims to solve these problems by providing a resin composition that can suppress the occurrence of cracks and provide a multilayer body that is less likely to develop flow marks, as well as a flat molded body, a multilayer body, and a molded article that use the resin composition. [Means for solving the problem]

[0005] In light of the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using a resin containing (meth)acrylic compound units and aromatic vinyl compound units, and by increasing the initial glass transition temperature, increasing the Charpy impact strength, and decreasing the melt viscosity of the resin composition. Specifically, the above problems were solved by the following means. <1> A resin composition comprising a resin containing (meth)acrylic compound units and aromatic vinyl compound units, wherein the total amount of the (meth)acrylic compound units and aromatic vinyl compound units in the resin composition is 55 mass% or more, the resin composition has an initial glass transition temperature (Tig) measured by differential scanning calorimetry of 135°C or more, and when the resin composition is molded into a 3 mm thick ISO test piece, the unnotched Charpy impact strength is 10.0 kJ / m 2 The unnotched Charpy impact strength is a value measured in the same manner as in JIS K 7111-1, except that the thickness of the ISO test piece was changed from 4 mm to 3 mm, and the resin composition was subjected to a test at 240°C for 1220 seconds. -1 A resin composition having a melt viscosity of 500 Pa·s or less at a shear rate of 1000 Pa·s or less. <2> When the resin composition is molded into a test piece having a thickness of 1 mm, the haze is 5.0% or less. <1> The resin composition according to claim 1. <3> The resin composition has an initial glass transition temperature (Tig) of 140°C or higher as measured by differential scanning calorimetry. <1> or <2> The resin composition according to claim 1. <4> The resin composition contains an acrylic resin (a) containing a (meth)acrylic compound unit and a styrene resin (b) as a resin containing an aromatic vinyl compound unit. <1> ~ <3> The resin composition according to any one of the above. <5> The acrylic resin (a) contains at least one of a cyclic acid anhydride unit, an imide unit, and a glutarimide unit. <4> The resin composition according to claim 1. <6> The acrylic resin (a) contains a cyclic acid anhydride unit and / or an N-substituted maleimide unit. <4> The resin composition according to claim 1. <7> The acrylic resin (a) contains an N-substituted maleimide unit. <5> or <6> The resin composition according to claim 1. <8> The acrylic resin (a) contains an N-phenylmaleimide unit and / or an N-cyclohexylmaleimide unit. <5> or <6> The resin composition according to claim 1. <9> the acrylic resin (a) contains 37 to 96 mass% of (meth)acrylic compound units, 1 to 60 mass% of aromatic vinyl compound units, and 3 to 74 mass% of maleic anhydride and / or N-substituted maleimide units (provided that the total of the (meth)acrylic compound units, aromatic vinyl compound units, and maleic anhydride and / or N-substituted maleimide units does not exceed 100 mass%), <4> ~ <8> The resin composition according to any one of the above. <10> The styrene resin (b) contains a cyclic acid anhydride unit. <4> ~ <9> The resin composition according to any one of the above. <11> the styrene resin (b) contains 68 to 84 mass% of aromatic vinyl compound units and 16 to 32 mass% of cyclic acid anhydride units (provided that the total of the aromatic vinyl compound units and the cyclic acid anhydride units does not exceed 100 mass%); <4> ~ <10> The resin composition according to any one of the above. <12> The styrene resin (b) contains a styrene unit. <4> ~ <11> The resin composition according to any one of the above. <13> The styrene resin (b) contains maleic anhydride units. <4> ~ <12> The resin composition according to any one of the above. <14> The content of the acrylic resin (a) is 15 to 85 parts by mass, and the content of the styrene resin (b) is 15 to 85 parts by mass, based on 100 parts by mass of the total content of the acrylic resin (a) and the styrene resin (b). <4> ~ <13> The resin composition according to any one of the above. <15> Further containing antioxidants and / or mold release agents, <1> ~ <14> The resin composition according to any one of the above. <16> <1> ~ <15> 1. A flat plate-shaped molded article formed from the resin composition according to any one of 1 to 8. <17> The thickness is 10 to 5,000 μm. <16> The flat plate-like molded article according to claim 1. <18> <16> or <17> A multilayer body comprising the flat plate-like molded body according to claim 1. <19> <16> or <17> A multilayer body having the flat plate-like molded body according to claim 1 and a layer containing a polycarbonate resin. <20> the plate-like molded article further includes a hard coat layer, and the hard coat layer is formed by laminating the layer containing the polycarbonate resin, the plate-like molded article, and the hard coat layer in this order. <19> The multilayer body according to claim 1. <21> Furthermore, one or both surfaces of the multilayer body are subjected to one or more of an anti-fingerprint treatment, an anti-reflection treatment, an anti-glare treatment, a weather resistance treatment, an anti-static treatment, an anti-fouling treatment, and an anti-blocking treatment. <18> ~ <20> 10. The multilayer body according to any one of the preceding items. <22> <18> ~ <21> A molded article formed from the multilayer body according to any one of the above items, having a portion with a radius of curvature of 50 mmR or less. <23> <18> ~ <21> 1. A method for producing a molded article, comprising hot bending the multilayer body according to any one of the above items at 133 to 143°C. [Effects of the Invention]

[0006] The present invention provides a resin composition capable of providing a multilayer body that can suppress the occurrence of cracks and is less likely to produce flow marks, as well as a flat molded body, a multilayer body, and a molded article using the resin composition. In particular, it has become possible to prevent the occurrence of cracks in the multilayer body even when molded at a high temperature of about 135°C. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing the structure of an example of an anti-reflection film. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the present embodiment is an example for explaining the present invention, and the present invention is not limited to only this embodiment. In this specification, the symbol "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit. In this specification, various physical properties and characteristic values ​​are those at 23°C unless otherwise specified. In the description of groups (atomic groups) in this specification, when a notation does not specify whether they are substituted or unsubstituted, it includes both groups (atomic groups) that have no substituents and groups (atomic groups) that have substituents. For example, the term "alkyl group" includes not only alkyl groups that have no substituents (unsubstituted alkyl groups) but also alkyl groups that have substituents (substituted alkyl groups). In this specification, when a notation does not specify whether they are substituted or unsubstituted, it is preferable that they be unsubstituted. In this specification, the term "(meth)acrylic compound" refers to either or both of an acrylic compound and a methacrylic compound, with a methacrylic compound being preferred. Furthermore, the acrylic resin includes not only an acrylate (co)polymer but also a methacrylate (co)polymer. The flat plate-like molded body and multilayer body in this specification are intended to include those in the shape of a film or sheet, respectively. The terms "film" and "sheet" refer to a molded body that is thin relative to its length and width and is generally flat. In addition, the "film" and "sheet" in this specification may be single-layer or multi-layer. In this specification, "parts by mass" indicates the relative amount of a component, and "% by mass" indicates the absolute amount of a component. In cases where the standards shown in this specification differ depending on the year and the measurement method, etc., the standards shall be based on the standards in effect at the time of filing unless otherwise stated.

[0009] The resin composition of the present embodiment is a resin composition containing a resin containing (meth)acrylic compound units and aromatic vinyl compound units, wherein the total amount of the (meth)acrylic compound units and aromatic vinyl compound units in the resin composition is 55 mass% or more, the resin composition has an initial glass transition temperature (Tig) measured by differential scanning calorimetry of 135°C or more, and when the resin composition is molded into a 3 mm thick ISO test piece, the unnotched Charpy impact strength is 10.0 kJ / m 2 The unnotched Charpy impact strength is a value measured in the same manner as in JIS K 7111-1, except that the thickness of the ISO test piece was changed from 4 mm to 3 mm, and the resin composition was subjected to 240°C for 1220 seconds. -1 The resin composition is characterized by having a melt viscosity at a shear rate of 500 Pa s or less. This configuration makes it possible to obtain a resin composition that can suppress the occurrence of cracks and provide a multilayer body that is less likely to develop flow marks. In particular, cracks are less likely to develop even when molded at a high temperature of about 135°C. For example, a multilayer body having a layer formed from the resin composition of the present embodiment (the flat plate-shaped molded body of the present embodiment) and a layer containing a polycarbonate resin (hereinafter sometimes referred to as the "polycarbonate resin layer") can be hot-bent at about 125°C, but a temperature of 135°C or higher is preferred because the hot-bending time can be effectively shortened, stress relaxation of the resin is accelerated, and springback is less likely to occur.

[0010] The mechanism is presumed to be as follows. That is, by increasing the glass transition temperature of the resin composition and ensuring that the Charpy impact strength is equal to or greater than a predetermined value, the occurrence of cracks can be effectively suppressed. Furthermore, by reducing the melt viscosity of the resin composition, the occurrence of flow marks can be effectively suppressed. That is, when the resin composition of this embodiment and another resin (e.g., polycarbonate resin) are multilayer extruded, there is a point where the resin composition of this embodiment and the other resin component join. At this time, if the difference in melt viscosity of the resins is too large, poor flow is likely to occur. In this embodiment, it is presumed that poor flow and flow marks can be effectively suppressed by bringing the melt viscosity of the resin composition closer to the melt viscosity of the resin co-extruded with the acrylic resin.

[0011] <Resin> The resin composition of this embodiment includes a resin containing (meth)acrylic compound units and aromatic vinyl compound units, and the total content of the (meth)acrylic compound units and aromatic vinyl compound units in the resin composition is 55% by mass or more. The inclusion of (meth)acrylic compound units tends to further improve pencil hardness and impact resistance, while the inclusion of aromatic vinyl compound units improves the refractive index, effectively suppressing interference fringes when the resin is combined with other resin layers, such as aromatic polycarbonate resins. Furthermore, by ensuring that the total content of the (meth)acrylic compound units and aromatic vinyl compound units in the resin composition is 55% by mass or more, the resin can achieve high pencil hardness and a high refractive index while maintaining transparency. Here, "(meth)acrylic compound units" refers to structural units composed of (meth)acrylic compounds in the resin, and "aromatic vinyl compound units" refers to structural units composed of aromatic vinyl compounds in the resin. In this embodiment, the resin containing (meth)acrylic compound units and aromatic vinyl compound units may be a blend of an acrylic resin (a) containing (meth)acrylic compound units and a styrene resin (b) containing aromatic vinyl compound units, or may be a copolymer containing (meth)acrylic compound units and aromatic vinyl compound units. The resin composition of this embodiment preferably contains both an acrylic resin (a) containing (meth)acrylic compound units and a styrene resin (b) containing aromatic vinyl compound units. By using the acrylic resin (a) and the styrene resin (b), the melt viscosity of the resulting resin composition can be effectively reduced while the heat resistance of the resin composition can be increased.

[0012] First, the (meth)acrylic compound will be described. The (meth)acrylic compound is not particularly limited as long as it contains a (meth)acrylic group, but a compound represented by formula (a1) is preferred. [ka] (In formula (a1), Ra 1 is a hydrogen atom or a methyl group, and Ra 2 is an aliphatic group. In the above formula (a1), Ra1 is a hydrogen atom or a methyl group, and a methyl group is preferred. 2 is an aliphatic group, preferably a linear or branched aliphatic group, more preferably a linear aliphatic group. Examples of the aliphatic group include alkyl groups (including cycloalkyl groups), alkynyl groups (including cycloalkynyl groups), and alkenyl groups (including cycloalkenyl groups). An alkyl group is preferred, a linear or branched alkyl group is more preferred, and a linear alkyl group is even more preferred. Ra 2 The aliphatic group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, even more preferably 1 to 3 carbon atoms, still more preferably 1 or 2 carbon atoms, and even more preferably 1 carbon atom. The (meth)acrylic compound represented by formula (a1) is preferably an alkyl (meth)acrylate (preferably an alkyl methacrylate), and more preferably a methyl (meth)acrylate (preferably a methyl methacrylate). By using methyl methacrylate, the impact strength and pencil hardness of the obtained flat-plate-shaped molded article tend to be improved.

[0013] Next, the aromatic vinyl compound will be described. Aromatic vinyl compounds are compounds that have a vinyl group and an aromatic ring group, and a wide range of compounds that can be copolymerized with (meth)acrylic compounds can be used. Aromatic vinyl compounds are CH2=CH-L 1 -Ar 1 Preferably, the compound is represented by the formula: 1 is a single bond or a divalent linking group, preferably a single bond or a divalent linking group with a formula weight of 100 to 500, more preferably a single bond or a divalent linking group with a formula weight of 100 to 300, and even more preferably a single bond. 1 When L is a divalent linking group, it is preferably an aliphatic hydrocarbon group or a group consisting of a combination of an aliphatic hydrocarbon group and -O-. 1 This refers to the mass (g) per mole of the part corresponding to Ar. Hereinafter, the same applies to other "formula weights." 1is an aromatic ring group, and is preferably a substituted or unsubstituted benzene ring group or naphthalene ring (preferably a benzene ring), and more preferably an unsubstituted benzene ring group.

[0014] More specifically, the aromatic vinyl compound preferably includes an aromatic vinyl compound represented by formula (b1). Formula (b1) [ka] (In formula (b1), Ra 3 is a substituent, and na is an integer of 0 to 6.

[0015] In formula (b1), Ra 3 is a substituent, and examples thereof include a halogen atom (preferably a chlorine atom, a fluorine atom, or a bromine atom), a hydroxyl group, an alkyl group (preferably an alkyl group having 1 to 5 carbon atoms), an aryl group (preferably a phenyl group), an alkenyl group (preferably an alkenyl group having 2 to 5 carbon atoms), an alkoxy group (preferably an alkoxy group having 1 to 5 carbon atoms), and an aryloxy group (preferably a phenoxy group). When na is 2 or more, a plurality of Ra 3 may be the same or different. Preferably, na is an integer of 5 or less, more preferably an integer of 4 or less, even more preferably an integer of 3 or less, even more preferably an integer of 2 or less, even more preferably an integer of 1 or less, and even more preferably 0.

[0016] The aromatic vinyl compound is preferably a compound having a molecular weight of 104 to 600, and more preferably a compound having a molecular weight of 104 to 400. Specific examples of the aromatic vinyl compound include styrene-based monomers (styrene derivatives) such as styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, methoxystyrene, monobromostyrene, dibromostyrene, fluorostyrene, and tribromostyrene, with styrene being particularly preferred.

[0017] Next, the mass ratio of the (meth)acrylic compound units to the aromatic vinyl compound units contained in the resin composition of this embodiment will be described. In the resin composition of this embodiment, the mass ratio of the (meth)acrylic compound units to the aromatic vinyl compound units is preferably 25 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 60 parts by mass or more, even more preferably 70 parts by mass or more, and even more preferably 75 parts by mass or more, of the aromatic vinyl compound units per 100 parts by mass of the (meth)acrylic compound units. By setting the mass ratio at or above the lower limit, the refractive index is improved, thereby effectively suppressing the occurrence of interference fringes when laminated with a polycarbonate resin layer. Furthermore, the mass ratio of the (meth)acrylic compound units to the aromatic vinyl compound units is preferably 250 parts by mass or less, more preferably 200 parts by mass or less, even more preferably 190 parts by mass or less, even more preferably 180 parts by mass or less, and even more preferably 175 parts by mass or less, of the aromatic vinyl compound units per 100 parts by mass of the (meth)acrylic compound units. By setting the mass ratio at or below the upper limit, the impact strength and abrasion resistance of a flat plate-shaped molded article formed from the resin composition of this embodiment tend to be further improved. The resin composition of the present embodiment may contain only one type of (meth)acrylic compound unit and one type of aromatic vinyl compound unit, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0018] Next, the acrylic resin (a) will be described. The resin composition of this embodiment preferably contains an acrylic resin (a) containing (meth)acrylic compound units. The proportion of (meth)acrylic compound units in the acrylic resin (a) is preferably more than 50% by mass, more preferably 55% by mass or more, even more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, and even more preferably 70% by mass or more, of all structural units excluding terminal groups. By making the proportion equal to or greater than the lower limit, scratch resistance tends to be further improved. The upper limit of the proportion of (meth)acrylic compound units in the acrylic resin (a) is preferably 100% by mass, preferably 90% by mass or less, and more preferably 85% by mass or less, of all structural units excluding terminal groups. The acrylic resin (a) may contain only one type of (meth)acrylic compound unit, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0019] The acrylic resin (a) may contain a monomer unit other than a (meth)acrylic compound unit. Examples of the other monomer include a monomer other than a (meth)acrylic compound that is copolymerizable with a (meth)acrylic compound. Specific examples of other monomer units include an aromatic vinyl compound unit, a cyclic acid anhydride unit, an imide structural unit, a lactone ring structural unit, and an aliphatic vinyl compound unit. A preferred example of the other monomer unit is at least one selected from an aromatic vinyl compound unit, a cyclic acid anhydride unit, a lactone ring structure unit, and an N-substituted maleimide unit. Another preferred example of the other monomer unit is at least one of a cyclic acid anhydride unit, an imide unit, a glutarimide unit, and a lactone ring structure unit. Another preferred example of the other monomer unit is one that contains a cyclic acid anhydride unit and / or an N-substituted maleimide unit. Another preferred example of the other monomer units is an aromatic vinyl compound unit and an N-substituted maleimide unit. Another preferred example of the other monomer units is an aromatic vinyl compound unit, an N-phenylmaleimide unit, and an N-cyclohexylmaleimide unit.

[0020] When the acrylic resin (a) contains an aromatic vinyl compound unit, the details are the same as those for the aromatic vinyl compound unit described above. The content of the aromatic vinyl compound unit is preferably 1% by mass or more, more preferably 3% by mass or more, of all structural units in the acrylic resin (a) excluding terminal groups. By adjusting the content to be equal to or greater than the lower limit, compatibility with styrene resins tends to be improved. When the acrylic resin (a) contains an aromatic vinyl compound unit, the content of the aromatic vinyl compound unit is preferably 49% by mass or less, more preferably 30% by mass or less, and may further be 25% by mass or less, 20% by mass or less, 10% by mass or less, or 7% by mass or less, of all structural units in the acrylic resin (a) excluding terminal groups. By adjusting the content to be equal to or less than the upper limit, scratch resistance and impact resistance tend to be further improved. The acrylic resin (a) may contain only one type of aromatic vinyl compound unit, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0021] Examples of the cyclic acid anhydride unit include a maleic anhydride unit and a glutaric anhydride unit, and the maleic anhydride unit is preferred. By including the cyclic acid anhydride unit, particularly the maleic acid unit, the effect of improving the compatibility with the styrene resin (b) and the effect of improving the heat resistance are more effectively exhibited. When the acrylic resin (a) contains a cyclic acid anhydride unit, the content thereof is preferably 1% by mass or more, more preferably 4% by mass or more, of all structural units in the acrylic resin (a) excluding the terminal groups. By making the content equal to or greater than the lower limit, heat resistance tends to be further improved. Furthermore, when the acrylic resin (a) contains a cyclic acid anhydride unit, the content thereof is preferably 40% by mass or less, more preferably 30% by mass or less, of all structural units in the acrylic resin (a) excluding the terminal groups. By making the content equal to or less than the upper limit, compatibility with the styrene resin (b) tends to be further improved. The acrylic resin (a) may contain only one type of cyclic acid anhydride unit, or may contain two or more types. When two or more types are contained, the total amount preferably falls within the above range.

[0022] Examples of the imide structural unit include an N-substituted maleimide unit and a glutarimide unit. Examples of the N-substituted maleimide unit include an N-phenylmaleimide unit, an N-cyclohexylmaleimide unit, an N-benzylmaleimide unit, and an N-(4-carboxyphenyl)maleimide unit, and an N-phenylmaleimide unit and / or an N-cyclohexylmaleimide unit are preferred. The disclosures in paragraphs 0030 to 0034 of JP 2018-009144 A can be found in the specification, the contents of which are incorporated herein by reference. For glutarimide units, the description in paragraphs 0040 to 0047 of JP 2018-009144 A can be referred to, the contents of which are incorporated herein by reference.

[0023] In this embodiment, the acrylic resin (a) contains an N-substituted maleimide unit, in particular an N-phenylmaleimide unit and / or an N-cyclohexylmaleimide unit, so that heat resistance and compatibility with the styrene resin (b) are more effectively exhibited. When the acrylic resin (a) contains an N-substituted maleimide unit or a glutarimide unit (preferably an N-substituted maleimide unit), the content thereof is preferably 5% by mass or more, and more preferably 10% by mass or more, of all structural units in the acrylic resin (a) excluding the terminal groups. By making the content equal to or greater than the lower limit, heat resistance tends to be further improved. Furthermore, when the acrylic resin (a) contains an N-substituted maleimide unit or a glutarimide unit (preferably an N-substituted maleimide unit), the content thereof is preferably 49% by mass or less, and more preferably 30% by mass or less, of all structural units in the acrylic resin (a) excluding the terminal groups, and may even be 25% by mass or less, 20% by mass or less, or 10% by mass or less. By making the content equal to or less than the upper limit, impact resistance and abrasion resistance tend to be further improved. The acrylic resin (a) may contain only one type of N-substituted maleimide unit or glutarimide unit, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0024] For the lactone ring structure, the description in paragraphs 0048 to 0050 of JP 2018-009144 A can be referred to, the contents of which are incorporated herein by reference. When the acrylic resin (a) contains a lactone ring unit, its content is preferably 1% by mass or more, more preferably 4% by mass or more, of all structural units in the acrylic resin (a) excluding the terminal groups. By making the content equal to or greater than the lower limit, heat resistance tends to be further improved. Furthermore, when the acrylic resin (a) contains a lactone ring structural unit, its content is preferably 40% by mass or less, more preferably 30% by mass or less, of all structural units in the acrylic resin (a) excluding the terminal groups. By making the content equal to or less than the upper limit, compatibility with the styrene resin (b) tends to be further improved. The acrylic resin (a) may contain only one type of lactone ring unit, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0025] The first embodiment of the acrylic resin (a) preferably contains 37 to 96 mass% of (meth)acrylic compound units (preferably methyl methacrylate units), 1 to 60 mass% of aromatic vinyl compound units (preferably styrene), and 3 to 74 mass% of units consisting of one or more of cyclic acid anhydride units, imide units, and lactone ring structural units (preferably maleic anhydride and / or N-substituted maleimide units, more preferably N-substituted maleimide units), and more preferably contains 48 to 93 mass% of (meth)acrylic compound units, 2 to 45 mass% of aromatic vinyl compound units, and 7 to 50 mass% of units consisting of one or more of cyclic acid anhydride units, imide units, and lactone ring structural units (preferably maleic anhydride and / or N-substituted maleimide units). However, the total of (meth)acrylic compound units, aromatic vinyl compound units, and units consisting of one or more of cyclic acid anhydride units, imide units, and lactone ring structural units (preferably maleic anhydride and / or N-substituted maleimide units) does not exceed 100% by mass. In the first embodiment, the total of (meth)acrylic compound units, aromatic vinyl compound units, and units consisting of one or more of cyclic acid anhydride units, imide units, and lactone ring structural units (preferably maleic anhydride and / or N-substituted maleimide units) is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass or more of all structural units of the acrylic resin (a) excluding the terminal groups.

[0026] A second embodiment of the acrylic resin (a) is a blend of the acrylic resin of the first embodiment and an acrylic resin (ax) containing 90% by mass or more of (meth)acrylic compound units. This configuration makes it possible to suppress the occurrence of cracks, to make the multilayer body less susceptible to flow marks, and to warp after high temperature and high humidity. The blend ratio (mass ratio) of the acrylic resin of the first embodiment to the acrylic resin (ax) containing 90 mass % or more of (meth)acrylic compound units is preferably 1 to 10:1, more preferably 2 to 9:1, even more preferably 3 to 8:1, still more preferably 3 to 7:1, and even more preferably 4 to 6:1.

[0027] The initial glass transition temperature (Tig) of the acrylic resin (a) is preferably 120°C or higher, more preferably 125°C or higher, even more preferably 130°C or higher, and may be 133°C or higher. By setting the temperature at or above the lower limit, the effect of preventing cracks from occurring during hot bending tends to be further improved. Furthermore, the initial glass transition temperature (Tig) of the acrylic resin (a) is preferably 170°C or lower, more preferably 160°C or lower, even more preferably 150°C or lower, and may be 140°C or lower. By setting the temperature at or below the upper limit, the effect of suppressing springback during hot bending tends to be further improved. When the resin composition of this embodiment contains two or more acrylic resins (a), the initial glass transition temperature (Tig) of the acrylic resins (a) is the Tig of the mixture. The glass transition temperature is measured according to the method described in the Examples below (the same applies to the weight-average molecular weight, pencil hardness, and glass transition temperature, weight-average molecular weight, and pencil hardness of the styrene resin (b)).

[0028] The weight-average molecular weight of the acrylic resin (a) is preferably 50,000 or more, more preferably 70,000 or more, even more preferably 100,000 or more, even more preferably 120,000 or more, and even more preferably 150,000 or more. By setting it to the lower limit or more, the impact strength of the obtained flat plate-shaped molded article can be further improved. The weight-average molecular weight of the acrylic resin (a) is preferably 300,000 or less, more preferably 250,000 or less, even more preferably 225,000 or less, even more preferably 210,000 or less, and even more preferably 200,000 or less. By setting it to the upper limit or less, the melt viscosity of the resin composition can be effectively reduced.

[0029] The pencil hardness of the acrylic resin (a) is preferably HB or higher, more preferably H or higher. By making the pencil hardness equal to or higher than the lower limit, the surface hardness of the obtained flat plate-like molded article can be further increased. The pencil hardness of the acrylic resin (a) is preferably 2H or lower, more preferably H or lower.

[0030] Next, the styrene resin (b) will be described. The resin composition of this embodiment preferably contains a styrene resin (b) as a resin containing an aromatic vinyl compound unit. The styrene resin (b) is a resin containing at least one styrene-based monomer unit, such as a styrene unit, an α-methylstyrene unit, an o-methylstyrene unit, or a p-methylstyrene unit, as an aromatic vinyl compound unit, and preferably contains a styrene unit. The proportion of aromatic vinyl compound units (preferably styrene-based monomer units) in the styrene resin (b) is preferably more than 50% by mass, more preferably 55% by mass or more, even more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, and even more preferably 70% by mass or more, of all structural units excluding terminal groups. By ensuring that the proportion is equal to or greater than the above lower limit, the refractive index is improved, which tends to effectively suppress interference fringes when laminated with a polycarbonate resin layer. The upper limit of the proportion of aromatic vinyl compound units in the styrene resin (b) is 100% by mass of all structural units excluding terminal groups. The styrene resin (b) may contain only one type of aromatic vinyl compound unit, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0031] The styrene resin (b) may contain a monomer unit other than an aromatic vinyl compound unit and an aromatic vinyl compound unit other than a styrene-based monomer unit. Examples of other monomers include monomers other than aromatic vinyl compounds that are copolymerizable with aromatic vinyl compounds. Specific examples of the other monomer units include a cyclic acid anhydride unit, an N-substituted maleimide unit, and an alkenyl cyanide unit, with a cyclic acid anhydride unit being preferred.

[0032] Examples of the cyclic acid anhydride unit include maleic anhydride units and glutaric anhydride units, and maleic anhydride units are preferred. By including cyclic acid anhydride units, particularly maleic acid units, the glass transition temperature of the resulting styrene resin (b) can be increased. When the styrene resin (b) contains a cyclic acid anhydride unit, the content thereof is preferably 16% by mass or more, more preferably 20% by mass or more, of all structural units in the styrene resin (b) excluding the terminal groups. Furthermore, when the styrene resin (b) contains a cyclic acid anhydride unit, the content thereof is preferably 32% by mass or less, more preferably 26% by mass or less, of all structural units in the styrene resin (b) excluding the terminal groups. By adjusting the content to be equal to or greater than the above-mentioned lower limit or equal to or less than the above-mentioned upper limit, compatibility with the acrylic resin tends to be further improved. Furthermore, by adjusting the content to be equal to or greater than the above-mentioned lower limit, the heat resistance of the entire resin composition can be improved. The styrene resin (b) may contain only one type of cyclic acid anhydride unit, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above-mentioned range.

[0033] The styrene resin (b) preferably contains 68 to 84 mass% of aromatic vinyl compound units (preferably styrene units) and 16 to 32 mass% of cyclic acid anhydride units (preferably maleic anhydride units), and more preferably contains 70 to 83 mass% of aromatic vinyl compound units and 17 to 30 mass% of cyclic acid anhydride units. However, the total of the aromatic vinyl compound units and the cyclic acid anhydride units does not exceed 100 mass%. The total of the aromatic vinyl compound units and the cyclic acid anhydride units is preferably 90 mass% or more, more preferably 95 mass% or more, and even more preferably 99 mass% or more of all structural units of the styrene resin (b) excluding the terminal groups.

[0034] The initial glass transition temperature (Tig) of the styrene resin (b) is preferably 130°C or higher, more preferably 135°C or higher, even more preferably 140°C or higher, and even more preferably 143°C or higher. By setting the temperature at or above the lower limit, it is possible to effectively suppress the occurrence of cracks during hot bending. Furthermore, the initial glass transition temperature (Tig) of the styrene resin (b) is preferably 180°C or lower, more preferably 160°C or lower, and even more preferably 155°C or lower. By setting the temperature at or below the upper limit, the effect of suppressing springback during hot bending tends to be further improved.

[0035] The weight-average molecular weight of the styrene resin (b) is preferably 20,000 or more, more preferably 25,000 or more, even more preferably 30,000 or more, even more preferably 40,000 or more, and even more preferably 60,000 or more. By setting it to be equal to or greater than the lower limit, the impact strength of the obtained flat plate-shaped molded article can be further improved. Furthermore, the weight-average molecular weight of the styrene resin (b) is preferably 150,000 or less, more preferably 130,000 or less, even more preferably 120,000 or less, even more preferably 100,000 or less, even more preferably 80,000 or less, and may be 70,000 or less. By setting it to be equal to or less than the upper limit, the melt viscosity of the resin composition can be effectively reduced.

[0036] The pencil hardness of the styrene resin (b) is preferably B or higher, more preferably HB or higher. By making it equal to or higher than the lower limit, the surface hardness of the obtained flat plate-like molded article can be further increased. Furthermore, the pencil hardness of the styrene resin (b) is preferably H or lower, more preferably HB or lower.

[0037] Next, the blend form of the acrylic resin (a) and the styrene resin (b) in the resin composition of this embodiment will be described. In this embodiment, based on 100 parts by mass of the total content of the acrylic resin (a) and the styrene resin (b), the content of the acrylic resin (a) is preferably 15 to 85 parts by mass and the content of the styrene resin (b) is 15 to 85 parts by mass, more preferably 20 to 80 parts by mass and the content of the styrene resin (b) is 80 to 20 parts by mass, and even more preferably 30 to 70 parts by mass and the content of the styrene resin (b) is 70 to 30 parts by mass. By adopting such a composition, scratch resistance, impact resistance, and heat resistance are all achieved, and cracking during hot bending can be effectively prevented.

[0038] In the resin composition of this embodiment, the total content of the (meth)acrylic compound units and aromatic vinyl compound units in the resin composition is 55% by mass or more, preferably 60% by mass or more, more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, and even more preferably 73% by mass or more. By making the total content equal to or greater than the lower limit, high pencil hardness and high refractive index tend to be more effectively exhibited. Furthermore, in the resin composition, the total content of the (meth)acrylic compound units and aromatic vinyl compound units is preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, and even more preferably 80% by mass or less. By making the total content equal to or less than the upper limit, the heat resistance and rigidity of the entire resin composition due to the other units tend to be improved. In this embodiment, the resins containing the (meth)acrylic compound units and aromatic vinyl compound units (preferably the acrylic resin (a) and the styrene resin (b)) preferably account for 90% by mass or more of the resin composition, more preferably 94% by mass or more, and even more preferably 97% by mass or more. The upper limit may be 99.9% by mass of the resin composition. Furthermore, examples of resin components other than the resin containing a (meth)acrylic compound unit and an aromatic vinyl compound unit include polycarbonate resins and polyarylate resins.

[0039] <Antioxidants> The resin composition of the present embodiment preferably contains an antioxidant. Examples of antioxidants include phenol-based antioxidants, amine-based antioxidants, phosphorus-based antioxidants, and thioether-based antioxidants. Among these, in this embodiment, phosphorus-based antioxidants and phenol-based antioxidants (more preferably hindered phenol-based antioxidants) are preferred. Phosphorus-based antioxidants are particularly preferred because they provide excellent color to molded articles.

[0040] The phosphorus-based antioxidant is preferably a phosphite-based antioxidant, and a phosphite compound represented by the following formula (1) or (2) is preferred. [ka] (In formula (1), R 11 and R 12 each independently represents an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms. [ka] (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.

[0041] In the above formula (1), R 11 , R 12 Each of the alkyl groups represented by R 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.

[0042] [ka] (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.

[0043] 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.

[0044] 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.

[0045] The content of the antioxidant is preferably 0.001 parts by mass or more, and more preferably 0.008 parts by mass or more, relative to 100 parts by mass of the resin composition. The upper limit of the content of the antioxidant is preferably 0.5 parts by mass or less, more preferably 0.3 parts by mass or less, even more preferably 0.2 parts by mass or less, even more preferably 0.15 parts by mass or less, still more preferably 0.10 parts by mass or less, and particularly preferably 0.08 parts by mass or less, relative to 100 parts by mass of the resin composition.

[0046] By setting the content of the antioxidant to the above lower limit or more, a molded product with better hue and heat discoloration resistance can be obtained. On the other hand, by setting the content of the antioxidant to the above upper limit or less, a flat-plate molded product with good wet heat stability can be obtained without deteriorating heat discoloration resistance. The antioxidant may be used alone or in combination of two or more. When two or more antioxidants are used, the total amount is preferably within the above range.

[0047] <Release agent> The resin composition of the present embodiment preferably contains a release agent. By including a mold release agent, the moldability of the flat plate-shaped molded article can be improved. The type of release agent is not particularly limited, but examples thereof include aliphatic carboxylic acids, esters of 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, and polysiloxane-based silicone oils.

[0048] For details about the release agent, please refer to paragraphs 0035 to 0039 of WO 2015 / 190162, the contents of which are incorporated herein by reference.

[0049] The content of the release agent is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, and even more preferably 0.01 parts by mass or more, relative to 100 parts by mass of the resin composition, and 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 0.2 parts by mass or less. The release agent may be used alone or in combination of two or more. When two or more types are used, the total amount is preferably within the above range.

[0050] <Other ingredients> In addition to the above components, the resin composition of the present embodiment may contain other thermoplastic resins, ultraviolet absorbers, 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. When contained, the total content of the above components is preferably 0.1 to 5% by mass of the resin composition.

[0051] <Physical properties of resin composition> The resin composition of this embodiment has an initial glass transition temperature (Tig) measured by differential scanning calorimetry of 135°C or higher, preferably 136°C or higher, more preferably 137°C or higher, even more preferably 138°C or higher, even more preferably 139°C or higher, and even more preferably 140°C or higher. By setting the temperature at or above the lower limit, cracking can be effectively suppressed. Furthermore, durability in environmental resistance tests such as moist heat tests and high-temperature tests tends to be further improved. The upper limit of the initial glass transition temperature (Tig) is not particularly limited, but a practical value is 145°C or lower, and it may also be 144°C or lower, or even 143°C or lower. By setting the temperature at or below the upper limit, the effect of suppressing springback during hot bending tends to be further improved. The resin composition of this embodiment preferably has a mid-glass transition temperature (Tmg) measured by differential scanning calorimetry of 139°C or higher, more preferably 140°C or higher, even more preferably 141°C or higher, even more preferably 142°C or higher, and even more preferably 143°C or higher. By setting the temperature at or above the lower limit, cracking can be effectively suppressed. Furthermore, durability in environmental resistance tests such as moist heat tests and high-temperature tests tends to be further improved. The upper limit of the mid-glass transition temperature (Tmg) is not particularly specified, but a practical value is 149°C or lower, and it may also be 148°C or lower, or even 147°C or lower. By setting the temperature at or below the upper limit, the effect of suppressing springback during hot bending tends to be further improved. The glass transition temperatures (Tig, Tmg) are measured according to the method described in the Examples below. The initial glass transition temperature (Tig) can be increased by adjusting the raw material monomers of the resin, or by increasing the molecular weight of the resin. The glass transition temperature of a resin is generally determined by the raw material monomers and molecular weight, and can be appropriately selected by those skilled in the art.

[0052] The resin composition of this embodiment is heated at 240°C for 1220 seconds. -1The melt viscosity at a shear rate of 500 Pa·s or less is preferably 495 Pa·s or less, more preferably 490 Pa·s or less, even more preferably 485 Pa·s or less, and even more preferably 480 Pa·s or less. The lower limit of the melt viscosity is preferably 250 Pa·s or more, more preferably 300 Pa·s or more, even more preferably 350 Pa·s or more, even more preferably 375 Pa·s or more, and even more preferably 400 Pa·s or more. By setting the viscosity within the above range, the occurrence of flow marks can be effectively suppressed. The melt viscosity is measured as described in the Examples below. The melt viscosity can be adjusted to the above range by adjusting the molecular weight of the resin or by adding a low molecular weight compound that does not adversely affect the resin.

[0053] The resin composition of this embodiment preferably has excellent transparency. Specifically, when the resin composition of this embodiment is molded to a thickness of 1 mm, the haze is preferably 5.0% or less, more preferably 2.0% or less, even more preferably 1.0% or less, even more preferably 0.4% or less, and even more preferably 0.2% or less. The lower limit is ideally 0%, but practically 0.01% or more. The haze is measured as described in the Examples section below.

[0054] The resin composition of this embodiment preferably has high (hard) pencil hardness. Specifically, the resin composition of this embodiment is molded to a thickness of 1 mm, and the pencil hardness measured in accordance with JIS K5600-5-4:1999 using a pencil hardness tester under a load of 750 g is preferably F or higher, more preferably H or higher. By making the pencil hardness F or higher, the hardness of the entire multilayer body can be increased, and scratch resistance can be improved. There is no particular upper limit, but a practical value is 3H or lower. The pencil hardness is measured as described in the Examples below.

[0055] The resin composition of the present embodiment preferably has excellent impact strength. Specifically, the unnotched Charpy impact strength measured in accordance with JIS K 7111-1, except that the thickness of the ISO test piece was changed from 4 mm to 3 mm, is 10.0 kJ / m 2 or more, 10.2 kJ / m 2 It is preferable that the concentration is 10.5 kJ / m or more. 2 It is more preferable that the Charpy impact strength is equal to or greater than the lower limit. By making the Charpy impact strength equal to or greater than the lower limit, the occurrence of cracks can be suppressed. The upper limit of the Charpy impact strength is not particularly limited, but is preferably 20.0 kJ / m 2 The following is practical: 13.0 kJ / m 2 Even if it is less than this, it will still fully meet the required performance. Examples of methods for increasing the Charpy impact strength include blending a known resin with high impact resistance such as polymethyl methacrylate, using a resin with a high molecular weight, or blending an impact modifier such as rubber.

[0056] <Flat-shaped molded body> The resin composition of the present embodiment is preferably processed into a flat plate-shaped molded article for use. That is, the flat plate-shaped molded article of the present embodiment is formed from the resin composition of the present embodiment. The flat plate-shaped molded article of the present embodiment has excellent moist heat resistance. Examples of the flat-plate-shaped molded article include a plate, a film, a sheet, and the like. Furthermore, the flat-plate-shaped molded article may be included in a multilayer body laminated on another substrate, as will be described in detail later. Furthermore, the flat-plate-shaped molded article of this embodiment may be incorporated into a part of the multilayer body and then subjected to bending or the like. The lower limit of the thickness of the plate-like molded body is, for example, 1 μm or more, preferably 10 μm or more, more preferably 20 μm or more, even more preferably 50 μm or more, even more preferably 80 μm or more, and may be 100 μm or more. By setting the thickness at or above the lower limit, molding becomes easier and hardness tends to be improved. There is no particular upper limit to the thickness of the plate-like molded body, but it is preferably 5,000 μm or less, more preferably 2,000 μm or less, even more preferably 1,000 μm or less, even more preferably 500 μm or less, and even more preferably 300 μm or less. In particular, as will be described in detail later, it is preferable that the plate-like molded body is thinner than the total thickness of the plate-like molded body and the polycarbonate resin layer. By adopting such a configuration, even when the multilayer body is hot-molded, cracking and springback are effectively suppressed. The flat plate-shaped molded article of this embodiment is molded by injection molding, extrusion molding using a T-die, or the like.

[0057] The flat plate-like molded article of this embodiment preferably has a pencil hardness of F or more, more preferably H or more, measured under a load of 750 g using a pencil hardness tester in accordance with JIS K5600-5-4:1999. By making the pencil hardness F or more, the hardness of the entire multilayer body can be increased, and scratch resistance can be improved. There is no particular upper limit, but a practical upper limit is 3H or less. The pencil hardness is measured as described in the Examples below.

[0058] <Multilayer body> The multilayer body of this embodiment includes the flat-plate-shaped molded body of this embodiment. Such a multilayer body has excellent surface hardness. Furthermore, the multilayer body of this embodiment is preferably a multilayer body having the flat-plate-shaped molded body of this embodiment and a layer containing a polycarbonate resin (polycarbonate resin layer). The polycarbonate resin layer usually serves as the base material of the multilayer body. The multilayer body of this embodiment preferably further includes a hard coat layer. The hard coat layer is preferably formed by laminating the layer containing the polycarbonate resin, the flat-plate molded body, and the hard coat layer in this order. The hard coat layer may also be provided on the polycarbonate resin layer side. Note that other layers may be present between the polycarbonate resin layer and the flat-plate molded body, and between the flat-plate molded body and the hard coat layer, as long as they do not deviate from the spirit of this embodiment. Furthermore, the multilayer body of the present embodiment preferably has a low refractive index layer on the surface of the hard coat layer opposite to the substrate (the polycarbonate resin layer). That is, the multilayer body can be used as an antireflection film. FIG. 1 is a schematic diagram showing an example of an anti-reflection film, in which 1 denotes a substrate (polycarbonate resin layer), 2 denotes a flat-plate-shaped molded body, 3 denotes a hard coat layer, and 4 denotes an anti-reflection layer. In FIG. 1, the substrate 1, the flat-plate-shaped molded body 2, the hard coat layer 3, and the anti-reflection layer 4 are laminated in this order; however, other layers may be included within the scope of the present embodiment. When the multilayer body includes other layers, it is preferable that one or both surfaces of the multilayer body be subjected to one or more of the following treatments: anti-fingerprint treatment, anti-reflection treatment, anti-glare treatment, weather resistance treatment, antistatic treatment, anti-fouling treatment, and anti-blocking treatment. An example of the outermost surface of the multilayer body in this case is a hard coat layer. Furthermore, 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. Examples of such treatments include adding an anti-blocking agent or providing a surface irregularity of the multilayer body. Furthermore, the multilayer body of this embodiment may include other layers in addition to those described above. Specific examples include an adhesive layer, a pressure-sensitive adhesive layer, and an anti-fouling layer.

[0059] Next, the substrate 1 will be described. The type of substrate 1 is not particularly limited, and any known substrate can be used as long as it satisfies the performance requirements of the multilayer body of this embodiment. Specifically, a resin substrate is preferred, and polyolefin resin, polyester resin, polycarbonate resin, acrylic resin, or polystyrene resin is more preferred, and a substrate containing polycarbonate resin is even more preferred. These may be used alone or may form a composite substrate containing two or more types. In the multilayer body of this embodiment, as described above, the substrate 1 is preferably a layer containing polycarbonate resin (polycarbonate resin layer). The proportion of polycarbonate resin in the polycarbonate resin layer is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0060] The polycarbonate resin is preferably an aromatic polycarbonate resin, and more preferably a bisphenol A polycarbonate resin. The bisphenol A polycarbonate resin refers to a resin having carbonate structural units derived from bisphenol A and its derivatives, and preferably has a structural unit represented by the following formula (B-1): * in the formula indicates a bonding position. [ka] In formula (B-1), X 1 represents the following structure: [ka] R 5 and R 6 is an alkyl group or a hydrogen atom, and at least one of them is preferably a methyl group, and more preferably both of them are methyl groups. Formula (B-1) is preferably represented by the following formula (B-2). [ka]

[0061] The content of the structural unit represented by formula (B-1) in the bisphenol A polycarbonate resin is preferably 70 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more, of all structural units excluding both terminals. There is no particular upper limit, and 100 mol% may be structural units represented by formula (B-1). Particularly preferred bisphenol A polycarbonates include resins in which substantially all structural units excluding both terminals are composed of structural units of formula (B-1). Here, "substantially all structural units excluding both terminals" means 99.0 mol% or more of all structural units excluding both terminals, preferably 99.5 mol% or more, and more preferably 99.9 mol% or more. The bisphenol A polycarbonate resin may have other structural units in addition to the carbonate structural units derived from bisphenol A and its derivatives. Examples of dihydroxy compounds constituting such other structural units include the aromatic dihydroxy compounds described in paragraph 0014 of JP 2018-154819 A, the contents of which are incorporated herein by reference.

[0062] Examples of the terminal structure of the bisphenol A type polycarbonate resin include an alkyl group-substituted phenoxy group and an alkoxycarbonylphenoxy group. The number of carbon atoms in the alkyl group of the alkyl group-substituted phenoxy group is preferably 1 to 10, more preferably 1 to 8, and even more preferably 2 to 5. Examples of the alkyl group-substituted phenoxy group include an m-methylphenoxy group, a p-methylphenoxy group, an m-propylphenoxy group, a p-propylphenoxy group, and a p-tert-butylphenoxy group. The number of carbon atoms in the alkoxy group of the alkoxycarbonylphenoxy group is preferably 1 to 20. From the viewpoint of heat resistance, the alkoxycarbonylphenoxy group is preferably an alkoxycarbonylphenoxy group having 1 to 10 carbon atoms, more preferably a p-tert-butylphenoxy group. The initial glass transition temperature of the polycarbonate resin is preferably 140 to 155°C.

[0063] The method for producing the bisphenol A polycarbonate resin is not particularly limited, and any method can be used, such as interfacial polymerization, melt transesterification, pyridine method, ring-opening polymerization of a cyclic carbonate compound, and solid-phase transesterification of a prepolymer. For further details of the polycarbonate resin, please refer to the descriptions in paragraphs 0040 to 0073 of JP-A-2019-035001 and paragraphs 0016 to 0043 of JP-A-2018-103518, the contents of which are incorporated herein by reference.

[0064] The substrate 1 may contain various resin additives as needed, as long as they do not significantly impair the desired physical properties. Examples of resin additives include antioxidants, release agents, flame retardants, anti-dripping agents, dyes and pigments (including carbon black), antistatic agents, anti-fogging agents, anti-blocking agents, flow improvers, plasticizers, dispersants, and antibacterial agents. Note that one type of resin additive may be contained, or two or more types may be contained in any combination and ratio.

[0065] The substrate 1 may be a single layer or a multilayer. The thickness of the substrate 1 (preferably a polycarbonate resin layer) is not particularly limited, but is, for example, 1 μm or more, preferably 30 μm or more, more preferably 35 μm or more, even more preferably 40 μm or more, even more preferably 50 μm or more, even more preferably 100 μm or more, even more preferably 300 μm or more, particularly preferably 500 μm or more, and may be 700 μm or more. The thickness of the substrate 1 is also preferably 10,000 μm or less, more preferably 5,000 μm or less, and may be 3,000 μm or less, or may be 2,500 μm or less.

[0066] As described above, the multilayer body of this embodiment preferably includes a flat-plate-shaped molded body and a substrate. In this case, the relationship between the thickness of the flat-plate-shaped molded body and the substrate (preferably a polycarbonate resin layer) preferably satisfies the following: thickness of the flat-plate-shaped molded body / [total thickness of the flat-plate-shaped molded body and the substrate]<1 / 5. By satisfying this relationship, the flat-plate-shaped molded body becomes thin as a whole, so that even when the multilayer body is heat-molded, cracking is more effectively suppressed and springback is more effectively suppressed. More specifically, to suppress springback, it is more effective to relieve residual stress from bending remaining in the entire multilayer body when the multilayer body is bent. From this perspective, it is more preferable to relieve residual stress not only in the substrate but also in the flat-plate-shaped molded body. By ensuring that the flat-plate-shaped molded body and the substrate satisfy the above relationship, residual stress derived from the flat-plate-shaped molded body is more easily relieved, and springback can be more effectively suppressed. In this embodiment, it is more preferable that the thickness of the plate-like molded body / [total thickness of the plate-like molded body and the substrate]<1 / 6, and even more preferable that the thickness of the plate-like molded body / [total thickness of the plate-like molded body and the substrate]<1 / 8. It is also preferable that the thickness of the plate-like molded body / [total thickness of the plate-like molded body and the substrate] is 1 / 35<, and more preferably 1 / 25<thickness of the plate-like molded body / [total thickness of the plate-like molded body and the substrate]. In particular, in this embodiment, it is more preferable that the plate-like molded body and the substrate satisfy the above-mentioned preferred ranges of the predetermined thicknesses, and that the multilayer body satisfy the preferred ranges of thicknesses described below, while satisfying the above relationship. By adopting such a configuration, the effects of the present invention can be more effectively achieved. In particular, in this embodiment, it is preferable that the initial glass transition temperature (Tig) of the flat plate-shaped molded body, the initial glass transition temperature (Tig) of the substrate (preferably the polycarbonate resin layer), and the hot bending temperature (°C) satisfy the following relationship: Tig of flat molded body ≧ Hot bending temperature (℃) > [Initial glass transition temperature of substrate (Tig) - 15℃] More preferably Tig temperature of flat molded body > Hot bending temperature (℃) > [Initial glass transition temperature of substrate (Tig) - 15℃] More preferably, Tig temperature of flat molded body > Hot bending temperature (℃) > [Initial glass transition temperature of substrate (Tig) - 10℃] By doing so, there is a tendency that the suppression of springback and the suppression of crack occurrence are further improved.

[0067] In this embodiment, the change in warpage of the multilayer body consisting of the flat-plate-shaped molded body (acrylic resin layer) and the polycarbonate resin layer before and after high-humidity heat treatment is preferably less than 700 μm, more preferably less than 200 μm. The lower limit of the change in warpage is ideally 0 μm, but practically 1 μm or more. The amount of warpage change is measured according to the description in the Examples section below.

[0068] Next, the hard coat layer will be described in detail. The hard coat layer that may be included in the multilayer body of this embodiment is a layer having a surface hardness higher than that of the substrate (for example, a polycarbonate resin layer). By including such a hard coat layer, the surface hardness of the multilayer body or molded article can be increased. The thickness of the hard coat layer is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 2 μm or more, even more preferably 4 μm or more, and even more preferably 5 μm or more. By making the thickness equal to or greater than the lower limit, the pencil hardness of the entire multilayer body due to the hard coat layer tends to be further improved. The upper limit of the thickness of the hard coat layer is preferably 20 μm or less, more preferably 15 μm or less, even more preferably 12 μm or less, even more preferably 10 μm or less, and even more preferably 8 μm or less. By making the thickness equal to or less than the upper limit, the processability during hot bending tends to be further improved.

[0069] The hard coat layer is preferably obtained by applying a hard coat material that can be cured by heat or active energy rays, and then curing the applied material. Examples of coating materials that can be cured using active energy rays include resin compositions composed of one or more monofunctional or polyfunctional (preferably di- to deca-functional) (meth)acrylate monomers or oligomers, and preferably resin compositions containing monofunctional or polyfunctional (preferably di- to deca-functional) urethane (meth)acrylate oligomers. These resin compositions preferably contain a photopolymerization initiator as a curing catalyst. Examples of thermosetting resin coatings include polyorganosiloxane-based and crosslinked acrylic-based coatings. Some of these resin compositions are commercially available as hard coating agents for acrylic or polycarbonate resin films or sheets, and an appropriate coating material may be selected taking into consideration suitability for the coating line. For the hard coat layer, the descriptions in paragraphs 0045 to 0055 of JP 2013-020130 A, paragraphs 0073 to 0076 of JP 2018-103518 A, and paragraphs 0062 to 0082 of JP 2017-213771 A can be referred to, the contents of which are incorporated herein by reference.

[0070] The total thickness of the multilayer body of this embodiment is not particularly limited, but is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 100 μm or more. The thicker the layer thickness, the more likely the rigidity of the multilayer body is to be improved. Furthermore, the total thickness of the multilayer body is preferably 10,000 μm or less, more preferably 5,000 μm or less, and may be 2,000 μm or less. By setting the layer thickness within this range, when the multilayer sheet is pressed between rolls and the resin is cooled during molding of the multilayer body, the resin is cooled all the way to the inside of the multilayer body, thereby improving the moldability of the multilayer body.

[0071] The multilayer body of the present embodiment can be formed by using a main extruder that extrudes a resin composition containing a polycarbonate resin and a sub-extruder that extrudes the resin composition of the present embodiment, melting the resin under the conditions of each resin used, introducing it into an extrusion die, laminating it inside the die and forming it into a sheet, or by forming it into a sheet and then laminating it.

[0072] <Molded products and methods for manufacturing molded products> Next, a molded article using the multilayer body of this embodiment and a method for manufacturing the molded article will be described. The molded article of this embodiment is a molded article formed from the multilayer body of this embodiment. The multilayer body of the present embodiment also has excellent resistance to thermal bending, and is therefore suitable for applications having curved portions, such as molded articles having a portion with a curvature radius of 50 mmR or less (preferably a curvature radius of 40 to 50 mmR). The molded article of this embodiment is preferably obtained by hot bending the multilayer body of this embodiment at 130 to 150°C (preferably 133 to 143°C). The multilayer body of this embodiment has excellent hot bending resistance, and is therefore particularly useful when formed into a molded article having a portion with a curvature radius of 50 mmR or less. Furthermore, from the viewpoint of preventing springback and cracking, the temperature is preferably 133°C or higher. By setting the temperature at or above the lower limit, the hot bending time can be shortened, and stress relaxation of the resin is accelerated, making springback less likely to occur, which is preferable. Furthermore, the hot bending temperature is preferably 147°C or lower, more preferably 144°C or lower, and even more preferably 143°C or lower.

[0073] <Application> The flat plate-like molded body, multilayer body, and molded article of this embodiment can be suitably used for optical parts, decorative products, anti-reflection molded articles, and the like. The flat plate-like molded body, multilayer body, and molded article of this embodiment are suitable for use in parts for display devices, electrical and electronic devices, office automation equipment, personal digital assistants, machine parts, home appliances, vehicle parts, various containers, lighting equipment, etc. Among these, they are particularly suitable for use in housings for various displays, electrical and electronic devices, office automation equipment, personal digital assistants, 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 molded article of this embodiment is preferably used as a sensor film for touch panels or an anti-reflection molded article for various displays. [Example]

[0074] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, processing details, processing procedures, etc. shown in the following examples can be appropriately changed 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.

[0075] <Raw materials> Acrylic resin (MMA resin) (A1) Nippon Shokubai, PML203, mass ratio of styrene:N-phenylmaleimide:N-cyclohexylmaleimide:MMA (methyl methacrylate) = 6 mass%:19 mass%:4 mass%:71 mass%, Tig: 135°C, weight average molecular weight: 189,000, pencil hardness H (A2) ALTUGLAS (registered trademark) V020 manufactured by Arkema, MMA: methyl acrylate = 97% by mass: 3% by mass, Tig: 109°C, weight average molecular weight: 127,000, pencil hardness: 3H (A3) Daicel-Evonik PLEXIMIDE TT50, a resin composition containing MMA and glutarimide structural units (MMA: glutarimide = 24% by mass: 67% by mass), initial glass transition temperature (Tig): 152°C, weight average molecular weight: 90,200, pencil hardness H

[0076] Styrene resin (St-MAH copolymer (styrene-maleic anhydride copolymer)) (B1) XIRANSO23110 manufactured by Polyscope, styrene:maleic anhydride = 77% by mass: 23% by mass, initial glass transition temperature (Tig): 145°C, weight average molecular weight: 74,300, pencil hardness: HB (B2) XIRANSO26080 manufactured by Polyscope, styrene:maleic anhydride = 74% by mass: 26% by mass, initial glass transition temperature (Tig): 150°C, weight average molecular weight: 47,600, pencil hardness: HB

[0077] St-MMA-MAH copolymer (C) Denka Co., Ltd., R-200, styrene:maleic anhydride:methyl methacrylate = 55% by mass: 19% by mass: 26% by mass, weight average molecular weight: 123,000, Tig: 124°C

[0078] (D) Antioxidant: ADK STAB PEP-36, the following compound, where tBu represents a t-butyl group. [ka]

[0079] (E) Release agent: Glycerin monostearate, manufactured by Riken Vitamin Co., Ltd., Rikemal S-100A

[0080] Polycarbonate resin layer (F) Bisphenol A polycarbonate resin having a terminal pt-butylphenoxy group, manufactured by Mitsubishi Engineering Plastics Corporation, E-2000F, weight average molecular weight: 53,000, initial glass transition temperature (Tig): 149°C

[0081] <Measurement of glass transition temperature> The glass transition temperatures of various resins and resin compositions were measured by carrying out two cycles of temperature increase and decrease according to the differential scanning calorimetry (DSC) measurement conditions below, and measuring the glass transition temperature during the second temperature increase cycle. The intersection of a line drawn by extending the low-temperature baseline toward the high temperature side with a tangent to the inflection point was defined as the initial glass transition temperature (Tig), the intersection of a line drawn by extending the high-temperature baseline toward the low temperature side with a tangent to the inflection point was defined as the final glass transition temperature, and the midpoint between the initial and final glass transition temperatures was defined as the intermediate glass transition temperature (Tmg). Measurement starting temperature: 30°C, heating rate: 10°C / min, final temperature: 250°C, heating rate: 20°C / min. Units shown are °C. The measurement device used was a differential scanning calorimeter (DSC, manufactured by Hitachi High-Tech Science Corporation, "DSC7020").

[0082] <Method for measuring weight average molecular weight> The weight average molecular weight (Mw) of each resin and resin composition was measured by gel permeation chromatography. Specifically, the gel permeation chromatography apparatus used was an LC-20AD system (Shimadzu Corporation), and an LF-804 (Shodex Corporation) was connected to the column. The column temperature was set to 40°C. The detector used was an RID-10A (Shimadzu Corporation) RI detector. Chloroform was used as the eluent, and a calibration curve was prepared using standard polystyrene (Tosoh Corporation). If the above gel permeation chromatography device, column, and detector are difficult to obtain, measurement can be performed using other devices with equivalent performance.

[0083] <Pencil hardness> The pencil hardness of the various resins and resin compositions was determined by measuring the pencil hardness of the flat molded articles prepared above using a pencil hardness tester under a load of 750 g in accordance with JIS K5600-5-4: 1999. Evaluation was carried out by five experts, and judged by majority vote.

[0084] Examples 1 to 5, Comparative Examples 1 to 9 <Production of Resin Composition (Pellets)> Each of the components described above was weighed out so as to obtain the amount added (each component in Tables 1 to 3 is expressed in parts by mass) shown in Tables 1 to 3. After mixing for 15 minutes in a tumbler, the mixture was melt-kneaded at a cylinder temperature of 260°C in a vented twin-screw extruder ("TEX30α" manufactured by The Japan Steel Works, Ltd.) with a screw diameter of 32 mm, and pellets were obtained by strand cutting.

[0085] <Melt viscosity measurement> The melt viscosity of the above resin composition was measured. Specifically, the pellets were pre-dried at 80°C for 3 hours, and then the melt viscosity was measured using a capillograph. The measurement was performed at a temperature of 240°C, a capillary length of 10 mm, a capillary diameter of 1 mm, a furnace diameter of 9.55 mm, and a shear rate of 1220 s -1 The unit is Pa·s. The capillograph used was a Capillograph 1D PMD-C manufactured by Toyo Seiki Seisakusho Co., Ltd.

[0086] <Production of 1 mm thick flat plate-shaped molded body> The obtained resin composition (pellets) was melt-kneaded at a cylinder temperature of 260°C using a vented twin-screw injection molding machine (Sodick "PE-100", twin-screw diameter 29 mm, intermeshing co-rotating type, plunger diameter 28 mm) and molded into a flat plate-shaped molded product (100 x 100 x 1 mm) at a mold temperature of 80°C.

[0087] <Haze measurement> The haze of the obtained tabular molded article was measured using a haze meter under the conditions of a D65 light source and a 10° field of view. The haze meter used was "HM-150" manufactured by Murakami Color Research Laboratory Co., Ltd. The unit is shown as %.

[0088] <Charpy impact strength measurement> The Charpy impact strength was measured in the same manner as in JIS K 7111-1, except that the thickness of the ISO test piece was changed from 4 mm to 3 mm. Specifically, the obtained resin composition (pellets) was melt-kneaded at a cylinder temperature of 260°C using a vented twin-screw injection molding machine (Sodick "PE-100", intermeshing co-rotating twin screws with a diameter of 29mm, plunger diameter of 28mm) and molded bodies (test pieces) measuring 80mm in length, 10mm in width, and 3mm in thickness were produced at a mold temperature of 70°C. Subsequently, a Charpy impact test without a notch was conducted in accordance with JIS K7111-1 except for the thickness, and the Charpy impact strength was measured. The unit is kJ / m. 2 As shown.

[0089] <Manufacturing multilayer bodies without hard coating> 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, a multilayer extruder having a 650 mm wide T-die connected to the feed block, and a multi-manifold die connected to each extruder. The resin compositions of the Examples or Comparative Examples shown in Tables 1-3 were introduced into the single-screw extruder with a 32 mm shaft diameter and extruded at a cylinder temperature of 250°C and a throughput of 3.6 kg / h. The polycarbonate resin (F) was continuously introduced into the single-screw extruder with a 65 mm shaft diameter and extruded at a cylinder temperature of 280°C and a throughput of 32.4 kg / h. The feed block connected to all extruders was equipped with a two-type, two-layer distributor pin, and the extrusion was performed at a temperature of 270°C, resulting in lamination. The extruded material was extruded into a sheet through a T-die connected to the die at 270°C, and cooled while a mirror surface was transferred onto three mirror-finishing rolls set at temperatures of 130°C, 140°C, and 180°C from the upstream side, to obtain each multilayer body. The total thickness of the central part of the obtained multilayer body was 1000µm, and the thickness of the acrylic resin layer was 100µm.

[0090] <Warp evaluation under high temperature and humidity conditions> A test piece measuring 10 cm in length and 6 cm in width was cut from the center of the resulting multilayer body without a hard coat. The test piece was placed in a two-point support holder and placed in an environmental tester set at 23°C and 50% relative humidity for at least 24 hours to condition it, after which the warpage was measured. This value was used as the pre-treatment warpage value. The test piece was then placed in the holder and placed in an environmental tester set at 85°C and 85% relative humidity, where it was held for 120 hours. The holder was then transferred to the environmental tester set at 23°C and 50% relative humidity, where it was held for 4 hours, after which the warpage was measured again. This value was used as the post-treatment warpage value. To measure the warpage, a 3D shape measuring instrument equipped with an electric stage was used. The removed test piece was placed horizontally with a convex upwards position and scanned at 1 mm intervals. The protrusion in the center was measured as the warpage. The difference in the amount of warpage before and after the treatment, i.e., (amount of warpage after treatment) - (amount of warpage before treatment), was evaluated as the amount of warpage change. In this case, when the flat-plate-shaped molded body (acrylic resin layer) side was convex, a "-" sign was added. A: The absolute value of the change in warpage was less than 200 μm. B: The absolute value of the amount of warpage change was 200 μm or more and less than 700 μm. C: The absolute value of the warpage change was 700 μm or more.

[0091] <Production of a multilayer body with a hard coat> A coating containing 60 parts by mass of a hexafunctional urethane acrylate oligomer (product name: U6HA, manufactured by Shin-Nakamura Chemical Co., Ltd.), 35 parts by mass of PEG200# diacrylate (product name: 4EG-A, manufactured by Kyoeisha Chemical Co., Ltd.), and 5 parts by mass of an oligomer containing fluorine-containing groups, hydrophilic groups, lipophilic groups, and UV-reactive groups (product name: RS-90, manufactured by DIC Corporation) in a total of 100 parts by mass, to which 1% by mass of a photopolymerization initiator (product name: I-184 [compound name: 1-hydroxycyclohexylphenyl ketone] manufactured by BASF Ltd.) was added, was applied using a bar coater to the surface of the acrylic resin layer of the multilayer structure without a hard coat prepared above, and then heated with a metal halide lamp (20 mW / cm 2 ) for 5 seconds to cure the hard coat. The film thickness of the hard coat layer was 6 μm.

[0092] <Heat press molding processability 1 (135°C, 7 minutes of heat bending)> For the hard-coated multilayer body obtained above, convex (male) and concave (female) molds with a curvature radius of 50 mmR were prepared. The multilayer body coated with the hard coat layer was preheated at 90°C for 1 minute before molding, placed in the mold with the surface coated with the hard coat layer facing convex, pressed at a mold temperature of 135°C for 7 minutes, and then naturally cooled to produce a hot-press molded product. The cracks in the bent portions of the heat-press molded products were visually evaluated by five experts, who made their judgments by majority vote. A: No cracks were found in the bent parts of the heat press molded product. B: Cracks were observed in the bent parts of the hot press molded product.

[0093] <Heat press molding processability 2 (140°C, 3 minutes of heat bending)> For the hard-coated multilayer body obtained above, convex (male) and concave (female) molds with a curvature radius of 50 mmR were prepared. The multilayer body coated with the hard coat layer was preheated at 90°C for 1 minute before molding, placed in the mold with the surface coated with the hard coat layer facing convex, pressed at a mold temperature of 140°C for 3 minutes, and then naturally cooled to produce a hot-press molded product. The cracks in the bent portions of the heat-press molded products were visually evaluated by five experts, who made their judgments by majority vote. A: No cracks were found in the bent parts of the heat press molded product. B: Cracks were observed in the bent parts of the hot press molded product.

[0094] <External flow marks> The presence or absence of flow marks was visually confirmed in the above <Manufacturing of multilayer body>. Evaluation was carried out by five experts and judged by majority vote. A: No flow marks were observed. B: Flow marks were observed.

[0095] [Table 1]

[0096] [Table 2]

[0097] [Table 3]

[0098] The Tig, Tmg, melt viscosity, haze, pencil hardness and unnotched Charpy impact strength in the above table are measured values ​​of a resin composition containing a resin containing a (meth)acrylic compound unit and an aromatic vinyl compound unit. [Explanation of symbols]

[0099] 1 Base material 2 Flat plate shaped body 3 Hard coat layer 4 Anti-reflection layer

Claims

1. A resin composition comprising a resin containing a (meth)acrylic compound unit and an aromatic vinyl compound unit, In the resin composition, the total amount of the (meth)acrylic compound units and the aromatic vinyl compound units is 55 mass% or more, The resin composition has an initial glass transition temperature (Tig) of 135°C or higher as measured by differential scanning calorimetry; When the resin composition was molded into a 3 mm thick ISO test piece, the unnotched Charpy impact strength was 10.0 kJ / m ２ The unnotched Charpy impact strength is a value measured in the same manner as in JIS K 7111-1, except that the thickness of the ISO test piece was changed from 4 mm to 3 mm, The resin composition was subjected to 240°C for 1220 seconds. －１ A resin composition having a melt viscosity of 500 Pa s or less at a shear rate of the resin composition contains an acrylic resin (a) containing a (meth)acrylic compound unit and a styrene resin (b) as a resin containing an aromatic vinyl compound unit, A resin composition, wherein the acrylic resin (a) contains an N-substituted maleimide unit.

2. The resin composition according to claim 1, wherein the resin composition has a haze of 5.0% or less when molded into a test piece having a thickness of 1 mm.

3. The resin composition according to claim 1 or 2, wherein the resin composition has an initial glass transition temperature (Tig) of 140°C or higher as measured by differential scanning calorimetry.

4. The resin composition according to any one of claims 1 to 3, wherein the acrylic resin (a) contains an N-phenylmaleimide unit and / or an N-cyclohexylmaleimide unit.

5. The resin composition according to any one of claims 1 to 4, wherein the acrylic resin (a) contains 37 to 96 mass% of (meth)acrylic compound units, 1 to 60 mass% of aromatic vinyl compound units, and 3 to 74 mass% of N-substituted maleimide units (provided that the total of the (meth)acrylic compound units, aromatic vinyl compound units, and N-substituted maleimide units does not exceed 100 mass%).

6. The resin composition according to any one of claims 1 to 5, wherein the styrene resin (b) contains 68 to 84 mass% of aromatic vinyl compound units and 16 to 32 mass% of cyclic acid anhydride units (provided that the total of the aromatic vinyl compound units and the cyclic acid anhydride units does not exceed 100 mass%).

7. The resin composition according to any one of claims 1 to 6, wherein the styrene resin (b) contains a styrene unit.

8. The resin composition according to any one of claims 1 to 7, wherein the styrene resin (b) contains maleic anhydride units.

9. The resin composition according to any one of claims 1 to 8, wherein the content of the acrylic resin (a) is 15 to 85 parts by mass and the content of the styrene resin (b) is 15 to 85 parts by mass, based on 100 parts by mass of the total content of the acrylic resin (a) and the styrene resin (b).

10. The resin composition according to any one of claims 1 to 9, further comprising an antioxidant and / or a mold release agent.

11. A flat plate-like molded article formed from the resin composition according to any one of claims 1 to 10.

12. The plate-like molded article according to claim 11, having a thickness of 10 to 5,000 μm.

13. A multilayer body comprising the tabular molded body according to claim 11 or 12.

14. A multilayer body comprising the tabular molded body according to claim 11 or 12 and a layer containing a polycarbonate resin.

15. The multilayer body according to claim 14 , further comprising a hard coat layer, wherein the hard coat layer is formed by laminating the layer containing the polycarbonate resin, the flat plate-like molded body, and the hard coat layer in this order.

16. The multilayer body according to any one of claims 13 to 15, further comprising one or both surfaces thereof subjected to one or more of an anti-fingerprint treatment, an anti-reflection treatment, an anti-glare treatment, a weather resistance treatment, an antistatic treatment, an anti-fouling treatment, and an anti-blocking treatment.

17. A molded article formed from the multilayer body according to any one of claims 13 to 16, having a portion with a radius of curvature of 50 mmR or less.

18. A method for producing a molded article, comprising hot bending the multilayer body according to any one of claims 13 to 16 at 133 to 143°C.

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