Method for manufacturing a bent resin sheet product and the bent resin sheet product

Abstract

This bend forming product of a resin sheet suppresses upward warpage of an end of a bent portion.　This is made possible by cutting the end of the bent portion of the bend forming product of the resin sheet.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a bent resin sheet product and to a bent resin sheet product. [Background technology]

[0002] Resin molded products are used in automotive interior parts such as instrument covers, as well as in the casings of home appliances, office automation equipment, personal computers, small portable devices, and touch panel displays for mobile phone terminals. Resin molded products used in these applications are manufactured by molding resin sheets.

[0003] Conventionally, the aforementioned molding resin sheet is molded into an appropriate shape depending on the application. For example, Patent Document 1 describes an invention relating to a method for manufacturing a polycarbonate resin molded article, which includes the steps of laminating a predetermined protective film to at least one side of a polycarbonate resin laminate formed on a polycarbonate resin sheet or polycarbonate resin layer as a base material, shaping by cutting or punching, and bending while heating. Patent Document 1 states that the polycarbonate resin molded by the above method is used for anti-glare products or protective products.

[0004] Patent Document 1 describes that a method of obtaining polycarbonate resin sheets by heat bending is preferred because it allows for the application of functionalities such as hard coating and polarizing properties to the sheet before heat bending, thus resulting in higher productivity compared to performing similar treatments after processing.

[0005] Furthermore, as a moldable resin sheet with pre-applied functionality, Patent Document 2 describes a decorative film in which a hard coat layer is applied by a curing method in which a film with an ultraviolet (UV) curable hard coat layer is decoratively molded and then cured by UV irradiation.

[0006] In addition, Patent Document 3 describes a molded article made of a polycarbonate resin produced by an injection press molding method, which is subjected to a hard coat treatment by a dip coating method and has a hardness layer on both surfaces.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] As described above, in the method for forming a resin sheet, although bending is highly productive and useful, it has been found that warping may occur at the ends of the bent molded body. As a result, the appearance of the obtained bent molded product may be distorted.

[0009] Therefore, the present invention provides a method for manufacturing a bent molded product that has no warping and excellent appearance.

Means for Solving the Problems

[0010] The inventors of the present invention conducted intensive research to solve the above problems. As a result, they found that the above problems can be solved by removing the warped ends, and thus completed the present invention. That is, the present invention is as follows, for example.

[0011] <1> A bending step of bending a resin sheet to obtain a bent molded body including ends having warping, A removing step of removing the ends having warping, A method for manufacturing a bent molded product, including the above steps. <2>The manufacturing method according to <1> above, wherein the resin sheet contains a polycarbonate resin. <3>The manufacturing method according to <2> above, wherein the resin sheet has a high-hardness resin layer containing a high-hardness resin on at least one surface of a base material layer containing a polycarbonate resin. <4>The manufacturing method according to <3> above, wherein the resin sheet has the high-hardness resin layer on one surface of the base material layer and a hard coat layer on the other surface of the base material layer. <5>The high-hardness resin is represented by the following general formula (1):

Chemical formula

Chemical formula

Chemical formula

[0012] According to the present invention, a method for manufacturing a bent molded product that is free from warping and has an excellent appearance is provided. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view of a bent molded body with curves at both ends. [Figure 2] This is a front view of a bent molded body with curves at both ends. [Figure 3] This is a perspective view of a bent molded body that has been bent into a V-shape. [Figure 4] This is a perspective view of a bent molded body that has been bent into an L-shape. [Figure 5] This is a perspective view of a bent molded body having a V-shaped bend for removal. [Modes for carrying out the invention]

[0014] The present invention will be described in detail below, but the present invention is not limited to the examples, and can be modified in any way as long as it does not deviate significantly from the content of the present invention.

[0015] <Method for manufacturing bent molded products> The method for manufacturing a bent molded product according to the present invention includes a bending molding step of bending a resin sheet to obtain a bent molded body including a curved end, and a removal step of removing the curved end.

[0016] As described above, when a resin sheet is bent, warping may occur at the ends of the bent molded body due to stresses and other factors generated during the bending process. For example, Figures 1 and 2 show a perspective view and a front view, respectively, of a bent molded body with warping at both ends.

[0017] The bent molded body 1 shown in Figures 1 and 2 is obtained by heat bending a resin sheet (80 mm x 170 mm, thickness: 2 mm) made of a polycarbonate resin base layer using an aluminum upper and lower die with a radius of 50 mm. The bent molded body 1 has curved ends 11 and 12. As a result, the appearance of the bent molded body is distorted. In addition, according to Figures 1 and 2, the curved ends 11 and 12 have a curve along their entire edge.

[0018] In contrast, the present invention removes the curved ends 11 and 12. This makes it possible to manufacture a bent molded product that is free from curves and has a superior appearance.

[0019] [Bending and forming process] The bending molding process includes bending a resin sheet to obtain a bent molded body that includes curved ends.

[0020] (Resin sheet) The resin sheet is not particularly limited, but it preferably contains a thermoplastic resin that can be bent by heat.

[0021] The thermoplastic resin is not particularly limited, but examples include polycarbonate (PC) resin, polyester resin (polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polyethylene naphthalate (PEN) resin, polybutylene naphthalate (PBN) resin, etc.), polyamide resin, polyurethane resin, acrylic resin (methacrylic resin, acrylic resin), polyolefin resin (polyethylene (PE) resin, polypropylene (PP) resin, polyvinyl chloride (PVC) resin, polytetrafluoroethylene (PTFE) resin, etc.), polystyrene resin, triacetylcellulose resin, copolymers containing at least one monomer that constitutes these resins, etc.

[0022] Of these, the resin sheet preferably contains polycarbonate (PC) resin, polyester resin, acrylic resin, polyolefin resin, or a copolymer containing at least one monomer constituting these resins, from the viewpoint of high transparency; more preferably contains polycarbonate (PC) resin, polyethylene terephthalate (PET) resin, methacrylic resin, acrylic resin, polyvinyl chloride (PVC) resin, or a copolymer containing at least one monomer constituting these resins; and even more preferably contains polycarbonate (PC) resin. In the above resin sheet, the thermoplastic resins described above may be used individually or in combination of two or more types.

[0023] The following describes in detail preferred forms in which the resin sheet contains polycarbonate resin.

[0024] When the resin sheet contains polycarbonate resin, the resin sheet has a base layer containing polycarbonate resin. The resin sheet may further have a high-hardness resin layer, a hard coat layer, etc. By pre-applying functional layers such as a high-hardness resin layer and a hard coat layer to the resin sheet used for bending, these can be bent together. This offers advantages such as forming a uniform functional layer on a curved surface and increased productivity compared to processing after bending.

[0025] In one embodiment, if the resin sheet includes a base layer and a high-hardness resin layer, the resin sheet may have a two-layer structure (base layer - high-hardness resin layer) including a base layer and a high-hardness resin layer disposed on the base layer, or it may have a three-layer structure (first high-hardness resin layer - base layer - second high-hardness resin layer) including a first high-hardness resin layer, a base layer disposed on the first high-hardness resin layer, and a second high-hardness resin layer disposed on the base layer.

[0026] In another embodiment, if the resin sheet includes a base layer and a hard coat layer, the resin sheet may have a two-layer structure (base layer - hard coat layer) including a base layer and a hard coat layer disposed on the base layer, or it may have a three-layer structure (first hard coat layer - base layer - second hard coat layer) including a first hard coat layer, a base layer disposed on the first hard coat layer, and a second hard coat layer disposed on the base layer.

[0027] In another embodiment, if the resin sheet includes a base layer, a high-hardness resin layer, and a hard coat layer, it may be a three-layer structure (base layer - high-hardness resin layer - hard coat layer) including a base layer, a high-hardness resin layer disposed on the base layer, and a hard coat layer disposed on the high-hardness resin layer, or it may be a three-layer structure (hard coat layer - base layer - high-hardness resin layer) including a hard coat layer, a base layer disposed on the hard coat layer, and a high-hardness resin layer disposed on the base layer. Furthermore, the resin sheet may have a four-layer structure (first hard coat layer - base layer - high hardness resin layer - second hard coat layer) including a first hard coat layer, a base layer disposed on the first hard coat layer, a high hardness resin layer disposed on the base layer, and a second hard coat layer disposed on the high hardness resin layer, or it may have a four-layer structure (first high hardness resin layer - base layer - second high hardness resin layer - hard coat layer) including a first high hardness resin layer, a base layer disposed on the first high hardness resin layer, a second high hardness resin layer disposed on the base layer, and a hard coat layer disposed on the second high hardness resin layer. Furthermore, the resin sheet may have a five-layer structure (first hard coat layer - first high hardness resin layer - base layer - second high hardness resin layer - second hard coat layer) including a first hard coat layer, a first high hardness resin layer disposed on the first hard coat layer, a base layer disposed on the first high hardness resin layer, a second high hardness resin layer disposed on the base layer, and a second hard coat layer disposed on the second high hardness resin layer.

[0028] Of the above, the resin sheet preferably has a high-hardness resin layer containing a high-hardness resin on at least one surface of the base layer containing polycarbonate resin, and more preferably has the high-hardness resin layer on one surface of the base layer and a hard coat layer on the other surface of the base layer.

[0029] Furthermore, according to another embodiment, it is preferable to have a structure consisting of a base layer, a base layer-high hardness resin layer, a base layer-high hardness resin layer-hard coat layer, a hard coat layer-base layer-high hardness resin layer, a first high hardness resin layer-base layer-second high hardness resin layer, a first hard coat layer-base layer-second high hardness resin layer, a first high hardness resin layer-base layer-second high hardness resin layer-hard coat layer, a first hard coat layer-base layer-high hardness resin layer-second hard coat layer, a first hard coat layer-first high hardness resin layer-base layer-second high hardness resin layer-second hard coat layer, and a base layer, a base layer-high hardness resin layer, a base layer-high hardness resin layer-hard coat It is more preferable to have a structure of a hard coat layer, a hard coat layer - a base layer - a high hardness resin layer, a first high hardness resin layer - a base layer - a second high hardness resin layer - a hard coat layer, a first hard coat layer - a base layer - a high hardness resin layer - a second hard coat layer, a first hard coat layer - a first high hardness resin layer - a base layer - a second high hardness resin layer - a second hard coat layer, and it is even more preferable to have a structure of a base layer - a high hardness resin layer, a base layer - a high hardness resin layer - a hard coat layer, a first high hardness resin layer - a base layer - a second high hardness resin layer - a hard coat layer, a first hard coat layer - a first high hardness resin layer - a base layer - a second high hardness resin layer - a second hard coat layer.

[0030] Furthermore, additional layers may exist between the base layer and the high-hardness resin layer, and between the high-hardness resin layer and the hard coat layer. These additional layers are not limited to, but may include adhesive layers, primer layers, etc.

[0031] The following describes each component of the aforementioned resin sheet.

[0032] Base material layer The base layer contains polycarbonate resin (a1). The base layer may further contain other resins, additives, etc.

[0033] Polycarbonate resin (a1) The polycarbonate resin (a1) is not particularly limited as long as it contains carbonate ester bonds, i.e., -[OR-OCO]- units (where R may contain an aliphatic group, an aromatic group, or both an aliphatic and an aromatic group, and may have a linear or branched structure) in its molecular main chain. However, it is preferably an aromatic polycarbonate resin, and in particular, it is preferable to use a polycarbonate resin containing the constituent units of the following formula (3a).

[0034] [ka]

[0035] Specifically, as the polycarbonate resin (a1), aromatic polycarbonate resins (for example, Yupiron S-2000, Yupiron S-1000, Yupiron E-2000; manufactured by Mitsubishi Engineering Plastics Co., Ltd.) can be used.

[0036] By using this type of polycarbonate resin, it is possible to obtain a resin sheet with superior impact resistance.

[0037] In recent years, polycarbonate resins to which a monovalent phenol, represented by the following general formula (3), has been added as a terminal inhibitor have been used to control the glass transition temperature of the polycarbonate resin. In the present invention, a polycarbonate resin to which such a terminal inhibitor has been added can also be used.

[0038] [ka]

[0039] In the formula, R 5 R represents an alkyl group having 8 to 36 carbon atoms, or an alkenyl group having 8 to 36 carbon atoms; 6Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or an aryl group having 6 to 12 carbon atoms; n is an integer of 0 to 4; here, the substituent is a halogen, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 12 carbon atoms. In the present specification, "alkyl group" and "alkenyl group" may be linear or branched and may have a substituent.

[0040] The monohydric phenol represented by the general formula (3) is preferably the one represented by the following general formula (4).

[0041]

Chemical formula

[0042] In the formula, R 5 represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 36 carbon atoms.

[0043] The carbon number of R in the general formula (3) or the general formula (4) 5 is more preferably within a specific numerical range. Specifically, 36 is preferable as the upper limit value of the carbon number of R 5 , 22 is more preferable, and 18 is particularly preferable. Also, 8 is preferable as the lower limit value of the carbon number of R 5 , and 12 is more preferable.

[0044] When the upper limit value of the carbon number of R in the general formula (3) or the general formula (4) 5 is appropriate, the solubility of the monohydric phenol (terminal stopper) in an organic solvent tends to be high, and the productivity during the production of the polycarbonate resin is high, which is preferable.

[0045] As an example, if the carbon number of R 5 is 36 or less, the productivity is high and the economy is good in producing the polycarbonate resin. R 5If the carbon number is 22 or less, monovalent phenols exhibit particularly excellent solubility in organic solvents, significantly increasing productivity and improving economic efficiency in the production of polycarbonate resins. Examples of polycarbonate resins using such monovalent phenols include Yupizeta T-1380 (manufactured by Mitsubishi Gas Chemical).

[0046] R in general formula (3) or general formula (4) 5 When the lower limit of the number of carbon atoms is appropriate, the glass transition temperature of the polycarbonate resin does not become too high, and it is preferable because it has suitable thermoformability.

[0047] For example, in general formula (4), R 5 When a monovalent phenol with a C16 alkyl group is used as the end-terminating agent, a polycarbonate resin with excellent glass transition temperature, melt flowability, moldability, and drawdown resistance can be obtained, and the solvent solubility of the monovalent phenol during the production of the polycarbonate resin is also excellent, making it particularly preferable.

[0048] Among the monovalent phenols represented by general formula (3) or general formula (4), it is particularly preferable to use either or both of hexadecyl p-hydroxybenzoate or 2-hexyldecyl p-hydroxybenzoate as the end-termination agent.

[0049] The weight-average molecular weight of the polycarbonate resin (a1) is preferably 15,000 to 75,000, more preferably 20,000 to 70,000, and even more preferably 20,000 to 65,000. A weight-average molecular weight of 15,000 or more for the polycarbonate resin (a1) is preferable because it can lead to higher impact resistance. On the other hand, a weight-average molecular weight of 75,000 or less is preferable because it allows the base layer to be formed with fewer heat sources and maintains thermal stability even when molding conditions are high. In this specification, the weight-average molecular weight is the weight-average molecular weight on a standard polystyrene basis, measured by gel permeation chromatography (GPC).

[0050] The Tg of the polycarbonate resin (a1) is preferably 90 to 190°C, more preferably 100 to 170°C, and even more preferably 110 to 150°C. The Tg of the polycarbonate resin (a1) can be controlled by appropriately adjusting the type and combination of constituent units of the polycarbonate resin (a1), the weight-average molecular weight, etc. In this specification, the glass transition temperature is the temperature measured using a differential scanning calorimetry device with a sample of 10 mg at a heating rate of 10°C / min and calculated using the midpoint method.

[0051] The polycarbonate resin (a1) contained in the base layer may be used alone or in combination of two or more types.

[0052] The polycarbonate resin (a1) content in the base layer is preferably 75 to 100% by mass, more preferably 90 to 100% by mass, and particularly preferably 100% by mass, relative to the total mass of the base layer. A polycarbonate resin content of 75% or more is preferable because it can further improve impact resistance.

[0053] Other resins Other resins are not particularly limited, but examples include polyester resins.

[0054] The polyester resin preferably contains terephthalic acid as its dicarboxylic acid component, but may also contain other dicarboxylic acid components.

[0055] For example, a polyester resin (so-called "PETG") obtained by polycondensation of a glycol component containing 20 to 40 mol% (total 100 mol%) of 1,4-cyclohexanedimethanol to 80 to 60 mol% of the main component, ethylene glycol, is preferred.

[0056] Other resins may be used individually or in combination of two or more types.

[0057] If other resins are included, their content is preferably 0 to 25% by mass, and more preferably 0 to 10% by mass, relative to the total mass of the base layer.

[0058] additives As additives, those commonly used in resin sheets can be used. Specifically, these include antioxidants, anti-coloring agents, anti-static agents, mold release agents, lubricants, dyes, pigments, plasticizers, flame retardants, resin modifiers, compatibilizers, and reinforcing materials such as organic and inorganic fillers. These additives may be used individually or in combination of two or more types.

[0059] The amount of additive is preferably 0 to 10% by mass, more preferably 0 to 7% by mass, and particularly preferably 0 to 5% by mass, relative to the total mass of the base layer.

[0060] The method of mixing the additive and resin is not particularly limited, and methods such as total compounding, dry blending of masterbatches, and total dry blending can be used.

[0061] Thickness of the base layer The thickness of the base material layer is preferably 0.3 to 10 mm, more preferably 0.3 to 5 mm, and even more preferably 0.3 to 3.5 mm.

[0062] High hardness resin layer The high-hardness resin layer contains a high-hardness resin. Other resins, additives, etc., may also be included as needed. In this specification, "high-hardness resin" refers to a resin with a higher hardness than the polycarbonate resin used as the base material, and has a pencil hardness of HB or higher, preferably HB to 3H, more preferably H to 3H, and even more preferably 2H to 3H. The pencil hardness of the high-hardness resin layer was evaluated using a pencil scratch hardness test in accordance with JIS K 5600-5-4:1999. Specifically, a pencil was pressed against the surface of the hard coat anti-glare layer at a 45-degree angle and with a load of 750g, gradually increasing the hardness, and the hardest pencil that did not leave a scratch was evaluated as the pencil hardness.

[0063] High hardness resin The high-hardness resin is not particularly limited, but it is preferable to include at least one selected from the group consisting of resins (B1) to (B5).

[0064] Resin (B1) The resin (B1) is a copolymer comprising a (meth)acrylic acid ester constituent unit (a) represented by general formula (1) and an aliphatic vinyl constituent unit (b) represented by general formula (2). In this case, the resin (B1) may further have other constituent units. In this specification, (meth)acrylic refers to methacrylic and / or acrylic.

[0065] [ka]

[0066] In the formula, R 1 is a hydrogen atom or a methyl group, preferably a methyl group.

[0067] Also R 2 R is an alkyl group having 1 to 18 carbon atoms, preferably an alkyl group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. Specifically, examples include methyl group, ethyl group, butyl group, lauryl group, stearyl group, cyclohexyl group, isobornyl group, etc. Of these, R2 The group is preferably a methyl group or an ethyl group, and more preferably a methyl group.

[0068] Note, R 2 When is a methyl group or an ethyl group, the (meth)acrylic acid ester constituent unit (a) represented by general formula (1) becomes a (meth)acrylic acid ester constituent unit, R 1 is a methyl group and R 2 When the group is a methyl group, the (meth)acrylic acid ester constituent unit (a) represented by general formula (1) becomes a methyl methacrylate constituent unit.

[0069] The (meth)acrylic acid ester constituent unit (a) represented by general formula (1) may be present in the resin (B1) as one type or as two or more types.

[0070] [ka]

[0071] In the formula, R 3 This is either a hydrogen atom or a methyl group, and is preferably a hydrogen atom.

[0072] R 4 This is a cyclohexyl group which may be substituted with a hydrocarbon group having 1 to 4 carbon atoms, and is preferably an unsubstituted cyclohexyl group.

[0073] R 3 is a hydrogen atom, and R 4 When is a cyclohexyl group, the aliphatic vinyl structural unit (b) represented by general formula (2) becomes a vinylcyclohexane structural unit.

[0074] The aliphatic vinyl constituent unit (b) represented by general formula (2) may be present in the resin (B1) as only one type or as two or more types.

[0075] In this specification, the "hydrocarbon group" may be linear, branched, or cyclic, and may have substituents.

[0076] Other constituent units are not particularly limited, but include constituent units derived from aromatic vinyl monomers containing unhydrogenated aromatic double bonds, which are produced in the process of polymerizing (meth)acrylic acid ester monomers and aromatic vinyl monomers and then hydrogenating the aromatic double bonds derived from the aromatic vinyl monomers to produce resin (B1). A specific example of other constituent units is the styrene constituent unit.

[0077] Other constituent units may be present in the resin (B1) as one type or as two or more types.

[0078] The total content of (meth)acrylic acid ester constituent units (a) and aliphatic vinyl constituent units (b) is preferably 90 to 100 mol%, more preferably 95 to 100 mol%, and particularly preferably 98 to 100 mol%, relative to the total constituent units of the resin (B1).

[0079] The content of the (meth)acrylic acid ester constituent unit (a) represented by general formula (1) is preferably 65 to 80 mol%, and more preferably 70 to 80 mol%, relative to the total constituent units of the resin (B1). A proportion of 65 mol% or more of the (meth)acrylic acid ester constituent unit (a) is preferable because it allows for the production of a resin layer with excellent adhesion to the substrate layer and surface hardness. On the other hand, a proportion of 80 mol% or less of the (meth)acrylic acid ester constituent unit (a) is preferable because it reduces the likelihood of warping due to water absorption of the resin sheet.

[0080] Furthermore, the content of the aliphatic vinyl constituent unit (b) represented by general formula (2) is preferably 20 to 35 mol%, and more preferably 20 to 30 mol%, relative to the total constituent units of the resin (B1). A content of 20 mol% or more of the aliphatic vinyl constituent unit (b) is preferable because it can prevent warping under high temperature and high humidity conditions. On the other hand, a content of 35 mol% or less of the aliphatic vinyl constituent unit (b) is preferable because it can prevent delamination at the interface with the substrate.

[0081] Furthermore, the content of other constituent units is preferably 10 mol% or less, more preferably 5 mol% or less, and particularly preferably 2 mol% or less, relative to the total constituent units of the resin (B1).

[0082] In this specification, "polymer" may have any of the following structures: random copolymer, block copolymer, or alternating copolymer.

[0083] The weight-average molecular weight of resin (B1) is not particularly limited, but from the viewpoint of strength and moldability, it is preferably 50,000 to 400,000, and more preferably 70,000 to 300,000.

[0084] The glass transition temperature of resin (B1) is preferably 110 to 140°C, more preferably 110 to 135°C, and particularly preferably 110 to 130°C. A glass transition temperature of 110°C or higher is preferable because it reduces the likelihood of deformation or cracking of the resin sheet in a hot or humid environment. On the other hand, a glass transition temperature of 140°C or lower is preferable because it provides excellent processability when molding by continuous thermal shaping using mirror-finish rolls or shaping rolls, or by batch thermal shaping using mirror-finish molds or shaping molds.

[0085] Specific examples of resin (B1) include Optimus 7500 and 6000 (manufactured by Mitsubishi Gas Chemical). The above-mentioned resin (B1) may be used alone or in combination of two or more types.

[0086] When using resin (B1) as the high-hardness resin, it is preferable to use Yupizeta T-1380 (manufactured by Mitsubishi Gas Chemical) as the polycarbonate resin (a1).

[0087] Furthermore, as a high-hardness resin, the constituent unit (R) represented by general formula (1) is used. 1 , R 2 Both are methyl groups; methyl methacrylate) is 75 mol%, and the constituent unit (R) represented by general formula (2) is 3 is a hydrogen atom, R 4 A resin (B1) is used which is a copolymer containing 25 mol% of a cyclohexyl group (vinylcyclohexane), and a polycarbonate resin (a1) is used which contains the constituent unit of general formula (3a), and a monovalent phenol (R) represented by general formula (4) is used as the end-stop agent. 5 A particularly preferred embodiment is one in which a carbon atom with 8 to 22 carbon atoms is used.

[0088] The method for producing resin (B1) is not particularly limited, but it is preferable to obtain it by polymerizing at least one (meth)acrylic acid ester monomer with at least one aromatic vinyl monomer, and then hydrogenating the aromatic double bond derived from the aromatic vinyl monomer.

[0089] The aromatic vinyl monomer is not particularly limited, but examples include styrene, α-methylstyrene, p-hydroxystyrene, alkoxystyrene, chlorostyrene, and their derivatives. Of these, the aromatic vinyl monomer is preferably styrene.

[0090] Known methods can be used for the polymerization of (meth)acrylic acid ester monomers and aromatic vinyl monomers, but they can be produced by methods such as bulk polymerization or solution polymerization.

[0091] The bulk polymerization method is carried out by continuously supplying a monomer composition containing the above-mentioned monomer and polymerization initiator to a complete mixing tank and performing continuous polymerization at 100 to 180°C. The above-mentioned monomer composition may optionally contain a chain transfer agent.

[0092] Examples of polymerization initiators, though not particularly limited, include organic peroxides such as t-amyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexanoate, benzoyl peroxide, 1,1-di(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-hexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)cyclohexane, t-hexylpropoxyisopropyl monocarbonate, t-amyl peroxy-n-octoate, t-butylperoxyisopropyl monocarbonate, and di-t-butyl peroxide, as well as azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), and 2,2'-azobis(2,4-dimethylvaleronitrile). These can be used individually or in combination of two or more.

[0093] The chain transfer agent is not particularly limited, but examples include α-methylstyrene dimer.

[0094] Examples of solvents used in solution polymerization include hydrocarbon solvents such as toluene, xylene, cyclohexane, and methylcyclohexane; ester solvents such as ethyl acetate and methyl isobutyrate; ketone solvents such as acetone and methyl ethyl ketone; ether solvents such as tetrahydrofuran and dioxane; and alcohol solvents such as methanol and isopropanol. These solvents may be used individually or in combination of two or more.

[0095] The solvent used in the hydrogenation reaction to hydrogenate the aromatic double bond derived from the aromatic vinyl monomer after polymerization of the (meth)acrylic acid ester monomer and the aromatic vinyl monomer may be the same as or different from the polymerization solvent described above. Examples include hydrocarbon solvents such as cyclohexane and methylcyclohexane, ester solvents such as ethyl acetate and methyl isobutyrate, ketone solvents such as acetone and methyl ethyl ketone, ether solvents such as tetrahydrofuran and dioxane, and alcohol solvents such as methanol and isopropanol.

[0096] The hydrogenation method is not particularly limited, and known methods can be used. For example, it can be carried out in a batch or continuous flow manner at a hydrogen pressure of 3 to 30 MPa and a reaction temperature of 60 to 250°C. A reaction temperature of 60°C or higher is preferable because it prevents the reaction time from becoming too long. On the other hand, a reaction temperature of 250°C or lower is preferable because side reactions such as molecular chain cleavage and hydrogenation of ester moieties do not occur or hardly occur.

[0097] Examples of catalysts used in hydrogenation reactions include solid catalysts in which metals such as nickel, palladium, platinum, cobalt, ruthenium, and rhodium, or oxides, salts, or complex compounds of these metals, are supported on porous carriers such as carbon, alumina, silica, silica-alumina, and diatomaceous earth.

[0098] In the hydrogenation reaction, it is preferable that 70% or more of the aromatic double bonds derived from the aromatic vinyl monomer are hydrogenated. That is, the unhydrogenated percentage of aromatic double bonds contained in the constituent units derived from the aromatic vinyl monomer is preferably less than 30%, more preferably less than 10%, and even more preferably less than 5%. An unhydrogenated percentage of less than 30% is preferable because it allows for the production of a resin with excellent transparency. The unhydrogenated portion of the constituent units may become other constituent units in the resin (B1).

[0099] Resin (B2) The resin (B2) is a copolymer containing 6 to 77% by mass of (meth)acrylic acid ester units, 15 to 71% by mass of styrene units, and 8 to 23% by mass of unsaturated dicarboxylic acid units. In this case, the resin (B2) may further contain other units.

[0100] The (meth)acrylic acid ester monomer constituting the (meth)acrylic acid ester constituent unit in the resin (B2) is not particularly limited, but examples include acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, and 2-ethylhexyl methacrylate. Of these, methyl methacrylate is preferred as the (meth)acrylic acid ester monomer. The above-mentioned (meth)acrylic acid ester monomer may be included alone as the (meth)acrylic acid ester constituent unit, or in combination of two or more types.

[0101] The content of (meth)acrylic acid ester constituent units is 6 to 77% by mass, preferably 20 to 70% by mass, relative to the total mass of resin (B2).

[0102] The styrene constituent unit in the resin (B2) is not particularly limited, and any known styrene monomer can be used. From the viewpoint of availability, examples of the styrene monomer include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, t-butylstyrene, etc. Of these, styrene is preferred as the styrene monomer from the viewpoint of compatibility. The above-mentioned styrene monomer may be included alone as the styrene constituent unit, or in combination of two or more types.

[0103] The styrene constituent unit content is 15 to 71% by mass, preferably 20 to 66% by mass, relative to the total mass of the resin (B2).

[0104] The unsaturated dicarboxylic acid anhydride monomers constituting the unsaturated dicarboxylic acid constituent units in the resin (B2) are not particularly limited, but examples include acid anhydrides such as maleic acid, itaconic acid, citraconic acid, and aconitic acid. Of these, maleic acid anhydride is preferred as the unsaturated dicarboxylic acid anhydride monomer from the viewpoint of compatibility with styrene monomers. The above-mentioned unsaturated dicarboxylic acid anhydride monomers may be included individually as unsaturated dicarboxylic acid constituent units, or in combination of two or more types.

[0105] The content of unsaturated dicarboxylic acid constituent units is 8 to 23% by mass, preferably 10 to 23% by mass, relative to the total mass of the resin (B2).

[0106] Other constituent units in the aforementioned resin (B2) include, for example, N-phenylmaleimide.

[0107] The content of other constituent units is preferably 10 mol% or less, more preferably 5 mol% or less, and particularly preferably 2 mol% or less, relative to the total constituent units of the resin (B2).

[0108] The total content of the above-mentioned (meth)acrylic acid ester constituent units, styrene constituent units, and unsaturated dicarboxylic acid constituent units is preferably 90 to 100 mol%, more preferably 95 to 100 mol%, and particularly preferably 98 to 100 mol%, relative to the total constituent units of the resin (B2).

[0109] The weight-average molecular weight of resin (B2) is not particularly limited, but is preferably 50,000 to 300,000, and more preferably 80,000 to 200,000.

[0110] The glass transition temperature of resin (B2) is preferably 90 to 150°C, more preferably 100 to 150°C, and particularly preferably 115 to 150°C.

[0111] Specific examples of resins (B2) include Resistify R100, R200, R310 (manufactured by Denka), Delpet 980N (manufactured by Asahi Kasei), and hw55 (manufactured by Daicel-Evonik). The above-mentioned resins (B2) may be used individually or in combination of two or more types.

[0112] When using resin (B2) as the high-hardness resin, it is preferable to use a polycarbonate resin (a1) that contains the constituent units of general formula (3a). Furthermore, a monovalent phenol (R) represented by general formula (4) is used as the end-stop agent. 5 A particularly preferred embodiment is one in which a polycarbonate with 8 to 22 carbon atoms is used. Examples of such polycarbonate resins include Yupizeta T-1380 (manufactured by Mitsubishi Gas Chemical) and Yupiron E-2000 (manufactured by Mitsubishi Engineering Plastics).

[0113] Furthermore, when using a high-hardness resin, specifically a copolymer resin (R100, R200, or R310; manufactured by Denka) (B2) composed of 6 to 26% by mass of methyl methacrylate units, 55 to 21% by mass of styrene units, and 15 to 23% by mass of maleic anhydride units, it is preferable to use Yupizeta T-1380 as the polycarbonate resin (a1).

[0114] Furthermore, when using a high-hardness resin, specifically a copolymer (R310; manufactured by Denka) consisting of 6% by mass of methyl methacrylate constituent units, 71% styrene, and 23% maleic anhydride (resin B2), it is particularly preferable to use Yupizeta T-1380 as the polycarbonate resin (a1).

[0115] The method for producing resin (B2) is not particularly limited, but examples include bulk polymerization and solution polymerization.

[0116] Resin (B3) The resin (B3) is a polymer containing a constituent unit (c) represented by general formula (5). In this case, it is preferable that the polymer further contains a constituent unit (d) represented by general formula (6). Furthermore, the resin (B3) may further contain other constituent units.

[0117] [ka]

[0118] The content of the constituent unit (c) represented by general formula (5) is preferably 50 to 100 mol%, more preferably 60 to 100 mol%, and particularly preferably 70 to 100 mol%, relative to the total constituent units of the resin (B3).

[0119] [ka]

[0120] The content of the constituent unit (d) represented by general formula (6) is preferably 0 to 50 mol%, more preferably 0 to 40 mol%, and particularly preferably 0 to 30 mol%, relative to the total constituent units of the resin (B3).

[0121] Other constituent units in the aforementioned resin (B3) include, for example, the constituent unit represented by the following formula (3a).

[0122] [ka]

[0123] The content of other constituent units is preferably 10 mol% or less, more preferably 5 mol% or less, and particularly preferably 2 mol% or less, relative to the total constituent units of the resin (B3).

[0124] The total content of constituent unit (c) and constituent unit (d) is preferably 90 to 100 mol%, more preferably 95 to 100 mol%, and even more preferably 98 to 100 mol%, relative to the total constituent units of resin (B3).

[0125] The weight-average molecular weight of resin (B3) is preferably 15,000 to 75,000, more preferably 20,000 to 70,000, and particularly preferably 25,000 to 65,000.

[0126] The glass transition temperature of resin (B3) is preferably 105 to 150°C, more preferably 110 to 140°C, and particularly preferably 110 to 135°C.

[0127] Specific examples of resin (B3) include Yupiron KH3410UR, KH3520UR, and KS3410UR (manufactured by Mitsubishi Engineering Plastics Corporation). The above-mentioned resin (B3) may be used individually or in combination of two or more types.

[0128] When using resin (B3) as the high-hardness resin, it is preferable to use a polycarbonate resin (a1) that includes the constituent units of general formula (3a). Furthermore, a monovalent phenol (R) represented by general formula (4) is used as the end-terminating agent. 5 A particularly preferred embodiment is one in which a polycarbonate resin with 8 to 22 carbon atoms is used. An example of such a polycarbonate resin is YupiZeta T-1380 (manufactured by Mitsubishi Gas Chemical). In particular, it is preferable to use Yupiron KS3410UR (manufactured by Mitsubishi Engineering Plastics) as resin (B3) and YupiZeta T-1380 (manufactured by Mitsubishi Gas Chemical) as polycarbonate resin (a1).

[0129] Furthermore, when using resin (B3) as the high-hardness resin, it is preferable to include other resins other than resins (B1) to (B6). In this case, the other resins other than resins (B1) to (B6) are preferably resins that do not contain constituent unit (c) but contain constituent unit (d), and more preferably resins consisting only of constituent unit (d). Specifically, aromatic polycarbonate resins (for example, Yupiron S-2000, Yupiron S-1000, Yupiron E-2000; manufactured by Mitsubishi Engineering Plastics Co., Ltd.) can be used.

[0130] If resins other than those (B1) to (B6) are included, resin (B3) is preferably included in a proportion of 45% by mass or more, more preferably 55% by mass or more, relative to the total amount of resin in the high-hardness resin layer.

[0131] The method for producing resin (B3) is not particularly limited, but it can be produced in the same manner as the method for producing polycarbonate resin (a1) described above, except that bisphenol C is used as the monomer.

[0132] Resin (B4) The resin (B4) is a copolymer containing 5 to 20% by mass of styrene structural units, 60 to 90% by mass of (meth)acrylic acid ester structural units, and 5 to 20% by mass of N-substituted maleimide structural units. The resin (B4) may further contain other structural units.

[0133] The styrene constituent unit in the resin (B4) is not particularly limited, and any known styrene monomer can be used. From the viewpoint of availability, examples of the styrene monomer include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, t-butylstyrene, etc. Of these, styrene is preferred as the styrene monomer from the viewpoint of compatibility. The above-mentioned styrene monomer may be included alone as the styrene constituent unit, or in combination of two or more types.

[0134] The styrene constituent unit content is 5 to 20% by mass, preferably 5 to 15% by mass, and more preferably 5 to 10% by mass, relative to the total mass of the resin (B4).

[0135] The (meth)acrylic acid ester monomer constituting the (meth)acrylic acid ester constituent unit in the resin (B4) is not particularly limited, but examples include acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, and 2-ethylhexyl methacrylate. Of these, the (meth)acrylic acid ester monomer is preferably methyl methacrylate. The above-mentioned (meth)acrylic acid ester monomer may be included alone as the (meth)acrylic acid ester constituent unit, or in combination of two or more types.

[0136] The content of (meth)acrylic acid ester constituent units is 60 to 90% by mass, preferably 70 to 90% by mass, and more preferably 80 to 90% by mass, based on the total mass of the resin (B4).

[0137] Examples of N-substituted maleimide structural units in the resin (B4) include structural units derived from N-arylmaleimides such as N-phenylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-naphthylmaleimide, N-hydroxyphenylmaleimide, N-methoxyphenylmaleimide, N-carboxyphenylmaleimide, N-nitrophenylmaleimide, and N-tribromophenylmaleimide. Of these, structural units derived from N-phenylmaleimide are preferred from the viewpoint of compatibility with acrylic resin. The above-mentioned structural units derived from N-substituted maleimides may be included individually as N-substituted maleimide structural units, or in combination of two or more types.

[0138] The content of N-substituted maleimide constituent units is 5 to 20% by mass, preferably 5 to 15% by mass, and more preferably 5 to 10% by mass, based on the total mass of the resin (B4).

[0139] Other constituent units include (meth)acrylic acid ester constituent units represented by general formula (1) and aliphatic vinyl constituent units represented by general formula (2). In this case, general formula (1) and general formula (2) are the same as those for resin (B1) described above.

[0140] The content of other constituent units is preferably 10 mol% or less, more preferably 5 mol% or less, and particularly preferably 2 mol% or less, relative to the total constituent units of the resin (B4).

[0141] The total content of styrene constituent units, (meth)acrylic acid ester constituent units, and N-substituted maleimide constituent units is preferably 90 to 100 mol%, more preferably 95 to 100 mol%, and even more preferably 98 to 100 mol%, relative to the total constituent units of the resin (B4).

[0142] The weight-average molecular weight of resin (B4) is preferably 50,000 to 250,000, and more preferably 100,000 to 200,000.

[0143] The glass transition temperature of resin (B4) is preferably 110 to 150°C, more preferably 115 to 140°C, and particularly preferably 115 to 135°C.

[0144] A specific example of resin (B4) is Delpet PM120N (manufactured by Asahi Kasei Corporation). Note that the above-mentioned resin (B4) may be used alone or in combination of two or more types.

[0145] When using resin (B4) as the high-hardness resin, it is preferable to use a polycarbonate resin (a1) that contains the constituent units of general formula (3a). Furthermore, a monovalent phenol (R) represented by general formula (4) is used as the end-stop agent. 5 A particularly preferred embodiment is one in which a polycarbonate resin with 8 to 22 carbon atoms is used. An example of such a polycarbonate resin is Yupizeta T-1380 (manufactured by Mitsubishi Gas Chemical). In particular, it is preferable to use Delpet PM-120N as the resin (B4), which consists of 7% styrene constituent units, 86% (meth)acrylic acid ester constituent units, and 7% N-substituted maleimide constituent units, and to use Yupizeta T-1380 as the polycarbonate resin (a1).

[0146] The method for producing resin (B4) is not particularly limited, but it can be produced by solution polymerization, bulk polymerization, etc.

[0147] Resin (B5) The resin (B5) is a copolymer containing 50 to 95% by mass of styrene structural units and 5 to 50% by mass of unsaturated dicarboxylic acid structural units. The resin (B5) may further contain other structural units.

[0148] As styrene constituent units, styrene monomers described in resin (B4) can be used. Resin (B5) may use these styrene constituent units individually or in combination of two or more types.

[0149] The styrene constituent unit content is preferably 50 to 95% by mass, more preferably 60 to 90% by mass, and even more preferably 65 to 87% by mass, based on the total mass of the resin (B5).

[0150] Examples of unsaturated dicarboxylic acid anhydride monomers that constitute the unsaturated dicarboxylic acid constituent units include acid anhydrides such as maleic acid, itaconic acid, citraconic acid, and aconitic acid. Of these, maleic anhydride is preferred from the viewpoint of compatibility with styrene monomers. The above-mentioned unsaturated dicarboxylic acid anhydride monomers may be used individually or in combination of two or more.

[0151] The content of unsaturated dicarboxylic acid constituent units is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and even more preferably 13 to 35% by mass, based on the total mass of the resin (B5).

[0152] Other constituent units include, for example, constituent units derived from the following general formula (1) and constituent units derived from general formula (2).

[0153] [ka]

[0154] In the formula, R 1 and R 2 The same applies as above.

[0155] [ka]

[0156] In the formula, R 3 and R 4 The same applies as above.

[0157] The content of other constituent units is preferably 10 mol% or less, more preferably 5 mol% or less, and even more preferably 2 mol% or less, relative to the total constituent units of the resin (B5).

[0158] The total content of styrene constituent units and unsaturated dicarboxylic acid constituent units is preferably 10 to 90 mol%, more preferably 20 to 85 mol%, and even more preferably 30 to 80 mol%, relative to the total constituent units of the resin (B5).

[0159] The weight-average molecular weight of the resin (B5) is preferably 50,000 to 250,000, and more preferably 100,000 to 200,000.

[0160] The glass transition temperature of resin (B5) is preferably 110 to 150°C, more preferably 115 to 140°C, and particularly preferably 115 to 137°C.

[0161] Specifically, examples of resin (B5) include XIBOND140 and XIBOND160 (manufactured by Polyscope Co., Ltd.). The above-mentioned resin (B5) may be used individually or in combination of two or more types.

[0162] When using resin (B5) as the high-hardness resin, it is preferable to use a polycarbonate resin (a1) that includes the constituent units of general formula (3a). Furthermore, a monovalent phenol (R) represented by general formula (4) is used as the end-terminating agent. 5 A particularly preferred embodiment is one in which a polycarbonate resin with 8 to 22 carbon atoms is used. An example of such a polycarbonate resin is Yupizeta T-1380 (manufactured by Mitsubishi Gas Chemical). In particular, it is preferable to use an alloy of XIBOND160, which consists of 78% by mass of styrene constituent units and 22% by mass of maleic anhydride constituent units, and an acrylic resin as the resin (B5), and to use Yupizeta T-1380 as the polycarbonate resin (a1).

[0163] The method for producing the resin (B5) is not particularly limited, but it can be produced by solution polymerization, bulk polymerization, or the like.

[0164] At least one selected from the group consisting of the above-mentioned resins (B1) to (B6) may be included as an alloy.

[0165] Specific examples of alloys are not particularly limited, but include alloys of two types of resin (B1), alloys of two types of resin (B2), alloys of two types of resin (B3), alloys of two types of resin (B4), alloys of two types of resin (B5), alloys of resin (B1) and resin (B2), alloys of resin (B2) and resin (B4), alloys of resin (B2) and other high-hardness resins, alloys of resin (B2) and acrylic resin, alloys of resin (B5) and acrylic resin, etc.

[0166] Other high-hardness resins include methyl methacrylate-styrene copolymer and acrylonitrile-butadiene-styrene copolymer.

[0167] Examples of the aforementioned acrylic resin include polymethyl methacrylate and copolymers of methyl methacrylate and methyl acrylate or ethyl acrylate. Examples of commercially available products include Acrypet (manufactured by Mitsubishi Chemical Corporation), Sumipex (manufactured by Sumitomo Chemical Co., Ltd.), and Parapet (manufactured by Kuraray Co., Ltd.).

[0168] When using an alloy of two types of resins, it is preferable to use an alloy of resins that have higher glass transition temperatures.

[0169] The aforementioned alloys may be used individually or in combination of two or more types.

[0170] There are no particular limitations on the method of manufacturing the alloy, but examples include using a twin-screw extruder with a screw diameter of 26 mm, melting and kneading the mixture at a cylinder temperature of 240°C, extruding it into strands, and then pelletizing it with a pelletizer.

[0171] The high-hardness resin and alloy contained in the high-hardness resin layer may be one type or two or more types. If two or more types are selected from resins (B1) to (B5) and alloys, they may be selected from the same or different categories. Furthermore, it may also contain high-hardness resins other than resins (B1) to (B5).

[0172] The content of the high-hardness resin in the high-hardness resin layer is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, and particularly preferably 100% by mass, based on the total mass of the high-hardness resin layer.

[0173] Other resins The high-hardness resin layer may contain resins other than the high-hardness resin. Examples of these other resins include methyl methacrylate-styrene copolymer, polymethyl methacrylate, polystyrene, polycarbonate, cycloolefin(co)polymer resin, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, and various elastomers. These other resins may be used individually or in combination of two or more.

[0174] The content of other resins is preferably 35% by mass or less, more preferably 25% by mass or less, and particularly preferably 10% by mass or less, based on the total mass of the high-hardness resin layer.

[0175] additives The high-hardness resin layer may contain additives, etc. The additives mentioned above may be used.

[0176] Thickness of the high-hardness resin layer The thickness of the high-hardness resin layer is preferably 10 to 250 μm, more preferably 30 to 200 μm, and particularly preferably 60 to 150 μm. A thickness of 10 μm or more is preferable because it increases surface hardness. On the other hand, a thickness of 250 μm or less is preferable because it increases impact resistance.

[0177] Lamination of a high-hardness resin layer onto a substrate layer As mentioned above, there may be further layers between the base layer and the high-hardness resin layer, but here we will describe the case where the high-hardness resin layer is laminated on the base layer.

[0178] The method for laminating the high-hardness resin layer onto the base layer is not particularly limited and includes methods such as overlapping individually formed base layers and high-hardness resin layers and heat-pressing them together; overlapping individually formed base layers and high-hardness resin layers and bonding them together with an adhesive; co-extruding the base layer and high-hardness resin layer; and in-mold molding the base layer into a pre-formed high-hardness resin layer to integrate them. Of these, the co-extrusion method is preferred from the viewpoint of manufacturing cost and productivity.

[0179] The co-extrusion method is not particularly limited. For example, in the feed block method, a high-hardness resin layer is placed on one side of the substrate layer in a feed block, extruded into a sheet shape with a T-die, and then cooled while passing through a molding roll to form the desired laminate. Alternatively, in the multi-manifold method, a high-hardness resin layer is placed on one side of the substrate layer in a multi-manifold die, extruded into a sheet shape, and then cooled while passing through a molding roll to form the desired laminate.

[0180] Furthermore, the above method can also be used to laminate a high-hardness resin layer onto a layer other than the base layer.

[0181] The total thickness of the base layer and the high-hardness resin layer is preferably 0.5 to 3.5 mm, more preferably 0.5 to 3.0 mm, and even more preferably 1.2 to 3.0 mm. A total thickness of 0.5 mm or more is preferable because it can maintain the rigidity of the sheet. On the other hand, a total thickness of 3.5 mm or less is preferable because it can prevent a decrease in the sensitivity of touch sensors when a touch panel is installed beneath the sheet.

[0182] The ratio of the thickness of the base layer to the total thickness of the base layer and the high-hardness resin layer is preferably 75% to 99%, more preferably 80% to 99%, and particularly preferably 85% to 99%. By setting it within this range, both hardness and impact resistance can be achieved.

[0183] Hard court layer The hard coat layer is not particularly limited, but it is preferable to use an acrylic hard coat. In this case, it is even more preferable to apply an anti-glare treatment to the hard coat layer. In this specification, "acrylic hard coat" means a coating film formed by polymerizing a monomer, oligomer, or prepolymer containing a (meth)acryloyl group as a polymerization group to form a crosslinked structure.

[0184] The composition of the acrylic hard coat preferably includes a (meth)acrylic monomer, a (meth)acrylic oligomer, and a surface modifier. In this case, the acrylic hard coat may further contain a photopolymerization initiator. In this specification, the term "photopolymerization initiator" refers to a photoradical generator.

[0185] The content of (meth)acrylic monomer is preferably 2 to 98% by mass, more preferably 5 to 50% by mass, and even more preferably 20 to 40% by mass, based on the total mass of (meth)acrylic monomer, (meth)acrylic oligomer, and surface modifier.

[0186] Furthermore, the content of (meth)acrylic oligomers is preferably 2 to 98% by mass, more preferably 50 to 94% by mass, and even more preferably 60 to 78% by mass, based on the total mass of (meth)acrylic monomers, (meth)acrylic oligomers, and surface modifiers.

[0187] Furthermore, the content of the surface modifier is preferably 0 to 15% by mass, more preferably 1 to 10% by mass, and even more preferably 2 to 5% by mass, relative to the total mass of the (meth)acrylic monomer, (meth)acrylic oligomer, and surface modifier.

[0188] Furthermore, if a photopolymerizing agent is included, the content of the photopolymerizing agent is preferably 0.001 to 7 parts by mass, more preferably 0.01 to 5 parts by mass, and even more preferably 0.1 to 3 parts by mass, based on 100 parts by mass of the total sum of the (meth)acrylic monomer, (meth)acrylic oligomer, and surface modifier.

[0189] (meth)acrylic monomer As (meth)acrylic monomers, any monomer containing a (meth)acryloyl group as a functional group within the molecule can be used. Specifically, this includes monofunctional monomers, difunctional monomers, or monomers with three or more functionalities.

[0190] Examples of monofunctional monomers include (meth)acrylic acid and (meth)acrylic acid esters.

[0191] Furthermore, specific examples of bifunctional and / or trifunctional (meth)acrylic monomers include diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol diacrylate, hydroxypivalate diacrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol diacrylate, 1,3-butylene glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, and polyethylene Examples include glycol diacrylate, 1,4-butanediol oligoacrylate, neopentyl glycol oligoacrylate, 1,6-hexanediol oligoacrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethoxytri(meth)acrylate, trimethylolpropane propoxytri(meth)acrylate, pentaerythritol tri(meth)acrylate, glycerylpropoxytri(meth)acrylate, trimethylolpropane trimethacrylate, trimethylolpropane ethylene oxide adduct triacrylate, glycerin propylene oxide adduct triacrylate, pentaerythritol tetraacrylate, and the like.

[0192] The hard coat layer may contain one or more (meth)acrylic monomers.

[0193] (Meth)acrylic oligomers Examples of (meth)acrylic oligomers include difunctional or polyfunctional urethane (meth)acrylate oligomers (hereinafter also referred to as polyfunctional urethane (meth)acrylate oligomers), difunctional or polyfunctional polyester (meth)acrylate oligomers (hereinafter also referred to as polyfunctional polyester (meth)acrylate oligomers), and difunctional or polyfunctional epoxy (meth)acrylate oligomers (hereinafter also referred to as polyfunctional epoxy (meth)acrylate oligomers).

[0194] Examples of the polyfunctional urethane (meth)acrylate oligomer include urethane reaction products of a (meth)acrylate monomer having at least one (meth)acryloyloxy group and a hydroxyl group in one molecule and a polyisocyanate; and urethane reaction products of an isocyanate compound obtained by reacting polyols with a polyisocyanate and a (meth)acrylate monomer having at least one or more (meth)acryloyloxy groups and hydroxyl groups in one molecule.

[0195] Examples of (meth)acrylate monomers having at least one (meth)acryloyloxy group and one hydroxyl group in a single molecule that can be used in the urethane reaction include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glycerin di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol penta(meth)acrylate.

[0196] Polyisocyanates used in urethane reactions include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, diisocyanates obtained by hydrogenating aromatic isocyanates from these diisocyanates (e.g., hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, etc.), di or tri polyisocyanates such as triphenylmethane triisocyanate and dimethylene triphenyl triisocyanate, or polyisocyanates obtained by increasing the amount of diisocyanate.

[0197] Polyols used in urethane formation reactions generally include aromatic, aliphatic, and alicyclic polyols, as well as polyester polyols, polyether polyols, and the like.

[0198] Typical examples of aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, ethylene glycol, propylene glycol, trimethylolethane, trimethylolpropane, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyric acid, glycerin, and hydrogenated bisphenol A.

[0199] Polyester polyols include those obtained by the dehydration condensation reaction of the aforementioned polyols with polycarboxylic acids. Specific examples of polycarboxylic acids include succinic acid, adipic acid, maleic acid, trimellitic acid, hexahydrophthalic acid, phthalic acid, isophthalic acid, and terephthalic acid. These polycarboxylic acids may also be anhydrides.

[0200] Examples of polyether polyols include polyalkylene glycols, as well as polyoxyalkylene-modified polyols obtained by the reaction of the aforementioned polyols or phenols with alkylene oxides.

[0201] The aforementioned polyfunctional polyester (meth)acrylate oligomer is obtained by a dehydration condensation reaction using (meth)acrylic acid, a polycarboxylic acid, and a polyol. Examples of polycarboxylic acids used in the dehydration condensation reaction include succinic acid, adipic acid, maleic acid, itaconic acid, trimellitic acid, pyromellitic acid, hexahydrophthalic acid, phthalic acid, isophthalic acid, and terephthalic acid. These polycarboxylic acids may also be anhydrides. Examples of polyols used in the dehydration condensation reaction include 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyrionic acid, trimethylolpropane, ditrimethylolpropane, pentaerythritol, and dipentaerythritol.

[0202] The aforementioned polyfunctional epoxy (meth)acrylate oligomer is obtained by an addition reaction between a polyglycidyl ether and (meth)acrylic acid. Examples of polyglycidyl ethers include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and bisphenol A diglycidyl ether.

[0203] The hard coat layer may contain one or more types of (meth)acrylic oligomers.

[0204] Surface modifier Surface modifiers are substances that alter the surface performance of a hard coat layer, including leveling agents, antistatic agents, surfactants, water- and oil-repellent agents, inorganic particles, and organic particles.

[0205] Examples of the leveling agent include polyether-modified polyalkylsiloxane, polyether-modified siloxane, polyester-modified hydroxyl group-containing polyalkylsiloxane, alkyl group-containing polyether-modified polydimethylsiloxane, modified polyether, and silicon-modified acrylic.

[0206] Examples of the antistatic agent include glycerin fatty acid ester monoglycerides, glycerin fatty acid ester organic acid monoglycerides, polyglycerin fatty acid esters, sorbitan fatty acid esters, cationic surfactants, and anionic surfactants.

[0207] Examples of the surfactant and water-repellent / oil-repellent agent include fluorine-containing surfactants and water-repellent / oil-repellent agents such as oligomers containing fluorine-containing groups and lipophilic groups, and oligomers containing fluorine-containing groups, hydrophilic groups, lipophilic groups, and UV-reactive groups.

[0208] Examples of the inorganic particles include silica particles, alumina particles, zirconia particles, silicon particles, silver particles, and glass particles.

[0209] Examples of the aforementioned organic particles include acrylic particles and silicon particles.

[0210] The hard coat layer may contain one or more surface modifiers.

[0211] Photopolymerization initiator Examples of photopolymerization initiators include monofunctional photopolymerization initiators. Specifically, these include 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone [Darocure 2959: Merck]; α-hydroxy-α,α'-dimethylacetophenone [Darocure 1173: Merck]; acetophenone-based initiators such as methoxyacetophenone, 2,2'-dimethoxy-2-phenylacetophenone [Irgacure-651], and 1-hydroxycyclohexylphenyl ketone; benzoin ether-based initiators such as benzoin ethyl ether and benzoin isopropyl ether; and other examples such as halogenated ketones, acylphosphenoxides, and acylphosphonates. These photopolymerization initiators may be used individually or in combination of two or more.

[0212] Method for forming a hard coat layer The method for forming the hard coat layer is not particularly limited, but for example, it can be formed by applying a hard coat liquid to a layer located beneath the hard coat layer (e.g., a high-hardness resin layer) and then photopolymerizing it.

[0213] The method for applying the hard coat liquid (polymerizable composition) is not particularly limited, and known methods can be used. Examples include spin coating, dip coating, spray coating, slide coating, bar coating, roll coating, gravure coating, meniscus coating, flexographic printing, screen printing, bead coating, and defacement.

[0214] Lamps used for light irradiation in photopolymerization have an emission distribution with a wavelength of 420 nm or less. Examples include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps. Among these, high-pressure mercury lamps or metal halide lamps are preferred because they efficiently emit light in the active wavelength range of the initiator and do not emit much short-wavelength light that would reduce the viscoelastic properties of the resulting polymer by crosslinking, nor long-wavelength light that would heat and evaporate the reaction composition.

[0215] The irradiation intensity of the above lamp is a factor that affects the degree of polymerization of the resulting polymer and is controlled appropriately for the performance of the target product. When a cleavage-type initiator having a typical acetophenone group is used, the illuminance is 0.1 to 300 mW / cm². 2 A range of 10 to 40 mW / cm² is preferred, particularly when using a metal halide lamp. 2 It is preferable to do so.

[0216] Photopolymerization reactions are inhibited by oxygen in the air or oxygen dissolved in the reactive composition. Therefore, it is desirable to carry out light irradiation using a method that can eliminate the reaction inhibition caused by oxygen. One such method is to cover the reactive composition with a film made of polyethylene terephthalate or Teflon to cut off contact with oxygen, and then irradiate the reactive composition with light through the film. Alternatively, the composition may be irradiated with light through a light-transmitting window in an inert atmosphere where oxygen has been replaced with an inert gas such as nitrogen or carbon dioxide.

[0217] When light irradiation is performed under an inert atmosphere, a constant amount of inert gas is introduced to maintain a low oxygen concentration in the atmosphere. The introduction of this inert gas generates a gas flow on the surface of the reactive composition, causing monomer evaporation. To suppress the level of monomer evaporation, the gas flow velocity of the inert gas is preferably 1 m / sec or less, and more preferably 0.1 m / sec or less, as the relative velocity to the laminate coated with the hard coat liquid moving under the inert gas atmosphere. By keeping the gas flow velocity within the above range, monomer evaporation due to the gas flow is substantially suppressed.

[0218] To improve the adhesion of the hard coat layer, the coating surface may be pretreated. Examples of known treatment methods include sandblasting, solvent treatment, corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone treatment, ultraviolet treatment, and primer treatment using resin compositions.

[0219] When applying an anti-glare treatment to the hard coat layer, there are no particular limitations on the method of the anti-glare treatment, but one method is to use an anti-glare type. For example, a high-hardness resin layer, a coating film obtained by applying a reactive composition, and an anti-glare type are laminated in this order. Next, the reactive composition is photopolymerized and the anti-glare type is demolded. The photopolymerized reactive composition (hard coat layer) will have a shape that reflects the rough surface of the anti-glare type at the contact surface with the anti-glare type. There are no particular limitations on the material of the anti-glare type as long as it transmits UV light, and glass, transparent resin, etc., can be used. Other methods of anti-glare treatment include adding particles to the reactive composition and treating the surface of the obtained hard coat layer. The degree of anti-glare treatment of the hard coat layer can be adjusted by controlling the type of anti-glare type used (surface haze, thickness, etc.) and the amount of particles added.

[0220] The hard coat layer may be further modified. For example, one or more of the following treatments can be applied: anti-reflective treatment, anti-fouling treatment, anti-static treatment, weather-resistant treatment, and anti-glare treatment. These treatment methods are not particularly limited, and known methods can be used. Examples include applying a reflective coating, depositing a dielectric thin film, or applying an anti-static coating.

[0221] Hard court layer The thickness of the hard coat layer is preferably 1 to 40 μm, and more preferably 2 to 10 μm. A hard coat layer thickness of 1 μm or more is preferable because it provides sufficient hardness. On the other hand, a thickness of 40 μm or less is preferable because it can suppress the occurrence of cracks during bending. The thickness of the hard coat layer can be measured by observing the cross-section with a microscope or the like and measuring the distance from the coating interface to the surface.

[0222] The surface roughness (Ra) of the hard coat layer is preferably 0.01 μm or more, more preferably 0.01 to 0.5 μm, and even more preferably 0.02 to 0.3 μm. A surface roughness (Ra) of 0.01 μm or more is preferable because the uneven surface shape scatters ambient light, preventing a decrease in visibility due to reflection of ambient light or image reflection. In this specification, the surface roughness (Ra) of the hard coat layer is the value obtained by calculating the centerline average roughness (Ra) according to the method specified in JIS-B-0601-1994.

[0223] The pencil hardness of the hard coat layer surface is preferably 2H or higher, and more preferably 2H to 3H. The pencil hardness of the hard coat layer is evaluated using a pencil scratch hardness test in accordance with JIS K 5600-5-4:1999. Specifically, pencils are pressed against the surface of the hard coat layer at a 45-degree angle and with a load of 750g, gradually increasing in hardness, and the hardest pencil that did not leave a scratch is evaluated as the pencil hardness.

[0224] (Bending and forming) The bending method is not particularly limited, but it is preferable to heat and soften the resin sheet before bending it. Bending methods include straight bending, radius bending, and hot press molding.

[0225] There are no particular restrictions on the heating method, but examples include pipe heaters, thermal infrared heaters, non-contact double-sided heating sandwich heaters, drying in a dryer, and electric furnaces. These heating methods may be used individually or in combination of two or more.

[0226] The heating area may be a part of the resin sheet (partial heating) or the entire sheet (overall heating). Partial heating is preferable from the viewpoint of being able to bend with a small bending radius (bending R) and being low cost. Overall heating is preferable from the viewpoint of being able to bend into various shapes, being less prone to warping and cracking.

[0227] The softening temperature varies depending on the resin sheet used, but it is preferably ±50°C of the softening point of the resin constituting the base layer (or the resin with the highest content if two or more resins are included), and more preferably ±30°C of the softening point. For example, in the case of a polycarbonate resin sheet mainly containing polycarbonate resin in the base layer, the softening temperature is preferably 100 to 150°C, and more preferably 110 to 140°C.

[0228] The bending process may or may not require the use of a mold.

[0229] If a mold is not used, one method involves making grooves or other cuts in the bending portion of the resin sheet, and then heating it to perform the bending process.

[0230] When using a mold, one method involves heating the resin sheet and bending it to fit the mold.

[0231] Of these methods, the method using a die is preferred for bending.

[0232] The mold may be a single-sided mold or a double-sided mold with convex and concave (male and female) surfaces, but from the viewpoint of obtaining a high-precision bent molded product, a double-sided mold with convex and concave (male and female) surfaces is preferable.

[0233] The shape of the mold is not particularly limited and can be designed as appropriate to match the shape of the resulting bent product. Examples include L-shaped, V-shaped, U-shaped, P-shaped, O-shaped, Z-shaped, etc.

[0234] The material of the mold is not particularly limited and examples include wooden molds; die steel, aluminum, aluminum alloys, zinc alloys, bismuth alloys, and other alloy molds; and ceramic molds. These materials may be used individually or in combination of two or more.

[0235] The heating temperature varies depending on the resin sheet used, but it is preferably the softening point of the resin constituting the base material layer (when including two or more resins, the resin with the highest content) ±50°C, and more preferably the softening point ±30°C. For example, when it is a polycarbonate resin sheet mainly containing a polycarbonate resin in the base material layer, the heating temperature is preferably 100 - 150°C, and more preferably 110 - 140°C.

[0236] The heating time varies depending on the heating area, heating temperature, presence or absence of a mold, shape of the mold, etc., but it is preferably 10 seconds to 1 hour, more preferably 1 minute to 30 minutes, and even more preferably 3 minutes to 15 minutes.

[0237] Usually, after bending, it is cooled and taken out of the mold to obtain a bent molded body.

[0238] (Bent molded body) The bent molded body includes an end portion having a warp.

[0239] In bending, non-uniform stress (compressive stress on the inner side of the bend and tensile stress on the outer side of the bend) and stress due to non-uniform cooling can occur in the resin sheet during bending. Also, when the resin sheet has a plurality of layers (for example, base material layer - high-hardness resin layer - hard coat layer), since the materials constituting each layer are different, stress can also occur between the layers. As a result, warping can occur at the end portion of the bent molded body.

[0240] Here, in this specification, "warp" means an unintended deformation caused by bending. Also, "end portion" means at least a part of the edge (hereinafter also referred to as "edge") that contacts the bending line (bending center) in the bent molded body. And "end portion having a warp" means the region having a warp among the end portions. In the case where all the edges have a warp, the "end portion having a warp" can be understood as the edge having a warp.

[0241] For example, FIG. 3 is a perspective view of a bent body bent into a V shape. The bent body 3 is bent into a V shape along a bending line 30. Here, at least a part of the end sides 31 and 32 in contact with the bending line 30 is an "end portion". For example, when a part of the end side 31 has a warp, that region becomes an "end portion having a warp". Also, for example, when the entire end side 31 has a warp, the entire end side 31 becomes an end portion having a warp (a warped end side).

[0242] Also, FIG. 4 is a perspective view of a bent body bent into an L shape. The bent body 4 is bent into an L shape along a bending line (bending center) 40. Here, at least a part of the end sides 41 and 42 in contact with the bending line is an "end portion". For example, when a part of the end side 41 has a warp, that region becomes an "end portion having a warp". Also, for example, when the entire end side 41 has a warp, the entire end side 41 becomes an end portion having a warp (a warped end side).

[0243] Note that the bent body may have warps at both end portions or may have a warp only at one end portion.

[0244] The size of the bent molded body varies depending on its application, but it is preferable to provide a removal area considering that warping occurs at the ends of the bent molded body and the removal process described later. For example, Figure 5 is a perspective view of a bent molded body with a removal area that has been bent into a V shape. The bent molded body 5 is bent into a V shape along the bending line 50. Here, the bent molded body 5 is designed to be larger than the bent molded product that will be ultimately manufactured. Specifically, it has removal areas 54 and 55 that are extended in the direction of the bending line (bending center) 50. The removal areas 54 and 55 are located at both ends, and warping occurs at the edges 51 and 52 of the removal areas 54 and 55. Therefore, by removing the removal areas 54 and 55 in the removal process described later, it is possible to manufacture a bent molded product that is the size as designed. In other words, in a preferred embodiment, the bending process is preferably a process of bending a resin sheet including a first removal region, a main body region, and a second removal region to obtain a bent molded body in which at least one of the first removal region and the second removal region has a curved end.

[0245] [Removal process] The removal process includes removing the warped ends.

[0246] (Removal) The removal process involves removing only the end with warping if warping is formed on a portion of the edge, or removing the entire edge if warping is present on the entire edge. Even if warping is only present on a portion of the edge, the entire edge may be removed instead of just the warped end. From a productivity standpoint, the removal process preferably includes removing the warped edge.

[0247] Furthermore, if only one of the two ends of the bent molded body has a warped end, the end without warping may be removed from the viewpoint of aesthetics of the resulting bent molded product. That is, in one embodiment, the removal step preferably includes removing the end without warping, and more preferably includes removing the end without warping.

[0248] The removal method is not particularly limited, and any known method may be used as appropriate. For example, a small cutting machine (such as a FANUC RoboDrill) may be used.

[0249] The removal area is not particularly limited, but it is preferable to remove at least the ends that are warped, and more preferably to remove the edges that are warped. If the bent molded body includes a removal area, it is preferable to remove that removal area.

[0250] [Bent molded product] According to one embodiment of the present invention, a bent molded product manufactured by the above-described manufacturing method is provided. The bent molded product is free from warping and has an excellent appearance.

[0251] Bent molded products are suitable for use in automotive interior parts such as instrument covers, as well as in casings for home appliances, office automation equipment, personal computers, small portable devices, and touch panel display surfaces for mobile phone terminals. [Examples]

[0252] Examples of the present invention are shown below, but the present invention is not limited to the embodiments shown.

[0253] [Example 1] A resin sheet having a base layer, a high-hardness resin layer, and a hard coat layer was subjected to bending molding.

[0254] (Manufacturing of resin sheets) A laminate consisting of a base material layer and a high-hardness resin layer was formed using a multilayer extrusion apparatus having a single-screw extruder with a shaft diameter of 35 mm, a single-screw extruder with a shaft diameter of 65 mm, feed blocks connected to each extruder, and T-dies connected to the feed blocks.

[0255] Specifically, a high-hardness resin (B2) (a copolymer of methyl methacrylate units: 21% by mass, styrene units: 64% by mass, and maleic anhydride units: 15% by mass, Resisphi R100 (manufactured by Denka)) was continuously introduced into a 35mm diameter single-screw extruder and extruded under conditions of cylinder temperature 230°C and discharge speed 2.6 kg / h. In addition, a polycarbonate resin (Yupizeta T-1380; manufactured by Mitsubishi Gas Chemical) was continuously introduced into a 65mm diameter single-screw extruder and extruded under conditions of cylinder temperature 240°C and discharge speed 83.0 kg / h.

[0256] The extruded high-hardness resin and polycarbonate resin were introduced into a feed block equipped with two types of two-layer distribution pins, and the high-hardness resin and polycarbonate resin were laminated at a temperature of 240°C. This was then introduced into a T-die at 240°C and extruded into a sheet. The sheet was then cooled and stretched using three mirror-finish rolls at temperatures of 120°C, 130°C, and 190°C from the upstream side, transferring a mirror finish to obtain a laminate of the high-hardness resin layer and the substrate layer. The stretching ratio was 1.3 times. The thickness of the resulting laminate (substrate layer - high-hardness resin layer) was 2 mm, and the thickness of the high-hardness resin layer was 60 μm near the center.

[0257] A hard coat layer was formed on the high-hardness resin layer side of the laminate (base layer - high-hardness resin layer) obtained above. The material of the hard coat layer is as follows:

[0258] • U6HA: Hetafunctional urethane acrylate oligomer (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) 60% by mass, • 4EG-A:PEG200# Diacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) 35% by mass, and · RS-90: A mixture of 5% by mass of an oligomer containing a fluorine group, a hydrophilic group, a lipophilic group, and a UV-reactive group (manufactured by DIC Corporation) with respect to 100 parts by mass. · Photoinitiator: 1 part by mass of I-184 (manufactured by BASF [Compound name: 1-hydroxy-cyclohexyl phenyl ketone]).

[0259] The above materials were applied to the high-hardness resin layer of the laminate using a bar coater, and then covered with a 2-mm-thick glass plate with a haze of 10% from above. From above the glass plate, a metal halide lamp (20 mW / cm 2 ) was applied for 5 seconds to cure the hard coat and attach the hard coat layer. Then, by peeling off the glass plate, a resin sheet having a structure of a base material layer - high-hardness resin layer - hard coat layer was produced. The film thickness of the hard coat layer was 6 μm.

[0260] (Bending forming process) Thermal bending forming (R bending) was performed.

[0261] Specifically, the produced resin sheet was cut into a rectangle of 80 mm × 170 mm and placed between the upper and lower dies made of aluminum with a radius of 50 mm. The upper and lower dies were closed with a force of 0.6 MPa to perform thermal bending forming of the resin sheet. The temperature of the upper and lower dies made of aluminum was 124°C. The die closing time was 5 minutes. In addition, warping occurred at both ends of the obtained bent formed body.

[0262] (Removing process) Both ends having warping of the obtained bent formed body were removed. Specifically, 10 mm inward from the ends of the 50-mm R portion was cut with a robot drill (manufactured by FUNAC) to produce a bent formed product of 60 mm × 170 mm (total length).

[0263] [Example 2] Bending forming of a resin sheet having the structure of the base material layer was performed.

[0264] (Production of resin sheet) A single-screw, 65mm diameter single-layer extruder was used to continuously introduce polycarbonate resin (Yupizeta T-1380 (manufactured by Mitsubishi Gas Chemical Co., Ltd.)), and the resin was extruded under the conditions of a cylinder temperature of 280°C and a discharge speed of 83.0 kg / h.

[0265] The extruded polycarbonate resin was introduced into a T-die at a temperature of 280°C and extruded into a sheet. A resin sheet consisting of a polycarbonate resin base layer was then produced by cooling and stretching the sheet while transferring a mirror finish using three mirror-finishing rolls at temperatures of 120°C, 130°C, and 190°C from the upstream side. The stretching ratio was 1.17 times. The thickness of the obtained resin sheet was 2 mm.

[0266] (Bending and removal processes) The bending and removal processes were performed in the same manner as in Example 1.

[0267] [Comparative Example 1] A resin sheet having a base layer and a high-hardness resin layer was subjected to bending molding.

[0268] (Manufacturing of resin sheets) A resin sheet (base layer - high-hardness resin layer - hard coat layer) was prepared by laminating a 6 mm thick hard coat layer onto the high-hardness resin layer side of a 2 mm thick laminate (base layer - high-hardness resin layer) using the same method as in Example 1.

[0269] (Bending and forming process) The bending process was carried out in the same manner as in Example 1, except that the prepared resin sheet was cut into a rectangle measuring 60 mm x 170 mm. However, warping was observed at both ends of the resulting bent molded body.

[0270] [Comparative Example 2] A resin sheet having a base layer structure was subjected to bending molding. (Manufacturing of resin sheets) A 2 mm thick resin sheet (base layer) was prepared using the same method as in Example 2.

[0271] (Bending and forming process) The bending process was carried out in the same manner as in Example 1, except that the prepared resin sheet was cut into a rectangle measuring 60 mm x 170 mm. However, warping was observed at both ends of the resulting bent molded body.

[0272] The bent molded products manufactured in Examples 1 and 2 and Comparative Examples 1 and 2 were visually observed, and the curvature of the ends of the bent molded products was evaluated. The results obtained are shown in Table 1 below.

[0273] [Table 1]

[0274] The results in Table 1 show that the bent molded products of Examples 1 and 2 are free from warping and have excellent appearance. [Explanation of symbols]

[0275] 1, 3, 4, 5 Bent molded body 11, 12 Ends with a curve 30, 40, 50 fold lines 31, 32, 41, 42, 51, 52 Edge 54, 55 Area for removal

Claims

1. A bending molding process involves bending a resin sheet to obtain a bent molded body that includes curved ends, A removal step to remove the end having the warp, Includes, A method for manufacturing a bent molded product, wherein the resin sheet contains polycarbonate resin.

2. The manufacturing method according to claim 1, wherein the resin sheet has a high-hardness resin layer containing a high-hardness resin on at least one surface of a base layer containing a polycarbonate resin.

3. The manufacturing method according to claim 2, wherein the resin sheet has the high-hardness resin layer on one side of the base material layer and the hard coat layer on the other side of the base material layer.

4. The aforementioned high-hardness resin, The following general formula (1): 【Chemistry 1】 (In the formula, R １ R is a hydrogen atom or a methyl group, ２ (These are alkyl groups with 1 to 18 carbon atoms.) (Meth)acrylic acid ester constituent unit (a) represented by the following general formula (2): 【Chemistry 2】 (In the formula, R ３ R is a hydrogen atom or a methyl group, ４ (This is a cyclohexyl group that may be substituted with a hydrocarbon group having 1 to 4 carbon atoms.) A resin (B1) which is a copolymer containing an aliphatic vinyl structural unit (b) represented by; A polymer resin (B2) containing 6 to 77% by mass of (meth)acrylic acid ester units, 15 to 71% by mass of styrene units, and 8 to 23% by mass of unsaturated dicarboxylic acid units; The following general formula (5): 【Transformation 3】 A polymer resin (B3) containing the constituent unit (c) represented by; A resin (B4) which is a copolymer containing 5 to 20% by mass of styrene constituent units, 60 to 90% by mass of (meth)acrylic acid ester constituent units, and 5 to 20% by mass of N-substituted maleimide constituent units; and A polymer resin (B5) containing 50 to 95% by mass of styrene structural units and 5 to 50% by mass of unsaturated dicarboxylic acid units. The manufacturing method according to claim 2 or 3, comprising at least one selected from the group consisting of the following.

5. The aforementioned resin (B3) is given by the following general formula (6): 【Chemistry 4】 The manufacturing method according to claim 4, wherein the copolymer further comprises a constituent unit (d) represented by .

6. The manufacturing method according to any one of claims 1 to 5, wherein the bending process is performed by heating and softening a resin sheet and then bending it.

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