Sheet for thermoforming, decorated sheet, and molded article using these

Abstract

To provide a thermoforming sheet which achieves both moldability and hardness.SOLUTION: A thermoforming sheet is obtained by laminating at least three layers of a layer (A layer) containing a polycarbonate-based resin, a layer containing an acrylic resin (B layer), and a layer (C layer) formed of an uncured product of an acrylate-based active energy ray-curable resin composition (C composition) in this order. A glass transition temperature (Tg) of the A layer is 100°C or higher and 145°C or lower.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a thermoforming sheet, a decorative sheet, and a molded article using the same, which are preferably used in a method of integrating a sheet with a design or function into a resin molded article by thermoforming in order to impart chemical resistance, scratch resistance, and design to the surface of the resin molded article.

Background Art

[0002] In recent years, due to the diversification of automobile designs and the demand for weight reduction of automobiles, the number of resin molded parts adopted in automobiles has been increasing. These resin molded parts are required to have designs such as wood grain and metallic appearance, and functions such as chemical resistance and scratch resistance. As methods for imparting design and functions, methods of integrating a sheet having a specific design or function such as a decorative sheet with a resin molded article have been proposed. As specific examples, the following two methods can be exemplified. (1) A method in which a sheet is previously thermoformed (vacuum forming, pressure air forming, etc.) into a specific shape, which is set in an injection mold, and molten resin is injected to form an injection molded body and at the same time integrate it with a preformed sheet. (2) A method of coating a previously produced resin molded article with a sheet by thermoforming (three-dimensional surface decoration molding). Both of these methods (1) and (2) require thermoforming of the sheet. The thermoforming sheet used has a hard coat layer to provide chemical resistance and scratch resistance, and the base sheet is required to be transparent so as not to inhibit the appearance of the design layer. Therefore, acrylic resins, polycarbonate resins, and polyester resins are generally used.

[0003] For example, Patent Document 1 discloses an example of a scratch-resistant sheet having an ultraviolet curable hard coat layer on a laminated sheet of a polycarbonate resin layer and an acrylic resin layer containing rubber particles. However, the hardened hard coat layer cannot follow three-dimensional molding, and when attempting to mold by the above methods (1) and (2), the hard coat layer will crack.

[0004] As a countermeasure described above, Patent Document 2 discloses an example of so-called two-stage curing in a laminated hard coat film in which an ultraviolet curable hard coat layer is formed on a base film. In this method, the hard coat layer is cured with a weak ultraviolet exposure amount before three-dimensional molding, and then post-exposure is performed after three-dimensional molding to achieve both moldability and surface hardness. However, such two-stage curing may cause variations in moldability depending on the state of the first-stage curing, and there is a concern that the product life may be significantly deteriorated.

[0005] (1) and (2) In the thermoforming sheet used in the method, the following characteristics are mainly required. First, moldability is required. That is, it is important to have sufficient extensibility to follow three-dimensional molding and to prevent appearance defects such as cracks from occurring even when stretched. In particular, when performing high-temperature preheating during molding, even if good extensibility is possessed before heating, there is a problem that the thermosetting of the functional layer progresses due to preheating and the extensibility deteriorates significantly. Second, surface hardness (pencil hardness, scratch resistance) is required. When the thermoforming sheet is integrated with a resin molded product, the functional layer is arranged on the outermost surface, and the surface function of the resin molded product is required. For this purpose, high surface hardness is required. Generally, there is a trade-off relationship between the hardness and extensibility of the hard coat layer, and it has been a conventional problem to achieve both characteristics.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a thermoforming sheet, a decorative sheet, and a molded article using these sheets, which achieve both formability and hardness. In particular, in order to impart chemical resistance and scratch resistance to the surface of a resin molded article, a thermoforming sheet, a decorative sheet, and a molded article using these sheets that are suitable for use in a method of integrating a sheet having these functions with a resin molded article by thermoforming are provided.

Means for Solving the Problems

[0008] It has been found that the above problems are solved by a thermoforming sheet obtained by laminating at least three layers of a layer containing a specific polycarbonate resin (layer A), a layer containing an acrylic resin (layer B), and a layer formed from an uncured acrylate-based active energy ray curable resin composition (composition C) in this order.

[0009] That is, according to the present invention, the following configurations are provided.

[0010] 1. A thermoforming sheet obtained by laminating at least three layers of a layer containing a polycarbonate resin (layer A), a layer containing an acrylic resin (layer B), and a layer formed from an uncured acrylate-based active energy ray curable resin composition (composition C) in this order, wherein the glass transition temperature (Tg) of the layer A is 100°C or higher and 145°C or lower.

[0011] 2. The thermoforming sheet according to item 1 above, wherein the layer A contains a polyester-based thermoplastic elastomer, and the polyester-based thermoplastic elastomer is composed of a hard segment composed of polybutylene terephthalate units and a soft segment composed of polyester units having an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid as dicarboxylic acid components and a diol having 5 to 15 carbon atoms as a diol component.

[0012] 3. The thermoforming sheet according to item 2 above, wherein the layer A contains 1 to 20 parts by weight of the polyester-based thermoplastic elastomer according to item 2 above with respect to 100 parts by weight of the polycarbonate resin.

[0013] 4. The B layer is the thermoforming sheet according to any one of the preceding items 1 to 3, which substantially does not contain rubber particles.

[0014] 5. The C layer is the thermoforming sheet according to any one of the preceding items 1 to 4, which contains 1 to 5 parts by weight of a hindered amine compound with respect to 100 parts by weight of the uncured product of an acrylate-based active energy ray curable resin composition (Composition C).

[0015] 6. The thermoforming sheet according to any one of the preceding items 1 to 5, wherein the pencil hardness of the surface of the cured layer obtained by irradiating the C layer with active energy rays and curing is H or more.

[0016] 7. The thermoforming sheet according to any one of the preceding items 1 to 6, which is provided with a protective film on the C layer, and the protective film is peelable from the C layer.

[0017] 8. The thermoforming sheet according to any one of the preceding items 1 to 7, wherein the total thickness of the forming sheet is in the range of 0.05 mm or more and 3 mm or less.

[0018] 9. A decorative sheet formed with a decorative layer on the side of the A layer of the thermoforming sheet according to any one of the preceding items 1 to 8, opposite to the B layer and the C layer sides.

[0019] 10. A method for manufacturing a molded body, characterized in that the thermoforming sheet according to any one of the preceding items 1 to 8 or the decorative sheet according to item 9 is pre-shaped into the shape of a mold cavity, placed in the mold, and integrated with the molding of the resin material at the same time, and then post-exposure is performed with active energy rays.

[0020] 11. A method for manufacturing a molded body, characterized in that the thermoforming sheet according to any one of the preceding items 1 to 8 or the decorative sheet according to item 9 is attached to the mold cavity side with a vacuum pressure, integrated with the molding of the resin material at the same time, and then post-exposure is performed with active energy rays.

Effect of the Invention

[0021] The thermoforming sheet and decorative sheet of the present invention are thermoforming sheets and decorative sheets that achieve both formability and hardness. In particular, in order to impart chemical resistance and scratch resistance to the surface of resin molded products, they are suitable for use in a method of integrating sheets having these functions with resin molded products by thermoforming. Resin molded bodies using these can be used for automotive interior materials, household appliances, cosmetic cases, interior and exterior building materials, etc., and the industrial effects they exhibit are exceptional.

Embodiments for Carrying Out the Invention

[0022] Hereinafter, the present invention will be described in detail.

[0023] (Layer (A layer) containing a polycarbonate-based resin) The polycarbonate-based resin used in the present invention is a polymer in which dihydroxy compounds are linked by carbonate ester bonds, and is usually obtained by reacting a dihydroxy component and a carbonate precursor by an interfacial polymerization method or a melt polymerization method.

[0024] Typical examples of the dihydroxy component include 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A), 2,2-bis{(4-hydroxy-3-methyl)phenyl}propane (bisphenol C), 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)-3-methylbutane, 2,2-bis(4-hydroxyphenyl)-3,3-dimethylbutane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)octane, 1,1-bis(4-hydroxyphenyl)decane, 9,9-bis{(4-hydroxy-3-methyl)phenyl}fluorene, 9,9-bis(4-hydroxyphenyl)fluorene, α,α'-bis(4-hydroxyphenyl)-m-diisopropylbenzene, isosorbide, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and the like. A homopolymer using these alone or a copolymer copolymerized with two or more of them may be used. Bisphenol A is preferred in terms of physical properties and cost. In the present invention, a polycarbonate in which 50 mol% or more of the bisphenol component is bisphenol A and / or bisphenol C is preferred, more preferably 70 mol% or more, and still more preferably 90 mol% or more.

[0025] Specific polycarbonates include a homopolymer of bisphenol A, a homopolymer of bisphenol C, a binary copolymer of bisphenol A and bisphenol C, a binary copolymer of bisphenol A and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, a binary copolymer of bisphenol A and 9,9-bis{(4-hydroxy-3-methyl)phenyl}fluorene, and the like. A homopolymer of bisphenol A is most preferred.

[0026] As the carbonate precursor, carbonyl halide, carbonate ester, haloformate, etc. are used, and specifically, phosgene, diphenyl carbonate, dihaloformate of dihydric phenol, etc. are mentioned.

[0027] When producing a polycarbonate resin by reacting the above-mentioned dihydric dihydroxy compound with a carbonate precursor by an interfacial polymerization method or a melt polymerization method, a catalyst, a terminal stopper, an antioxidant for dihydric phenol, etc. may be used as necessary. Further, the polycarbonate resin may be a branched polycarbonate resin copolymerized with a polyfunctional aromatic compound having trifunctionality or higher, or a polyester carbonate resin copolymerized with an aromatic or aliphatic difunctional carboxylic acid, or a mixture of two or more of the obtained polycarbonate resins may be used.

[0028] The molecular weight of the polycarbonate resin is preferably in the range of 13,000 to 40,000 expressed as the viscosity average molecular weight. If the molecular weight is lower than 13,000, the sheet becomes brittle, and cracks and burrs are likely to occur during thermoforming. If it is higher than 40,000, the melt viscosity of the resin composition with the polyester-based thermoplastic elastomer becomes too high, and melt film formation may be difficult. The molecular weight is more preferably 15,000 to 35,000, still more preferably 20,000 to 32,000, and particularly preferably 22,000 to 28,000. When the polycarbonate resin is a mixture of two or more kinds, it represents the molecular weight of the whole mixture. Here, the viscosity average molecular weight is the specific viscosity (η sp ) of a solution obtained by dissolving 0.7 g of polycarbonate in 100 mL of methylene chloride at 20 °C, and the viscosity average molecular weight (M) is calculated from the following formula. η sp / c = [η] + 0.45 × [η] 2 c [η] = 1.23 × 10 -4 M 0.83 (However, c = 0.7 g / dL, [η] is the intrinsic viscosity)

[0029] The glass transition temperature of the layer (layer A) containing the polycarbonate resin of the present invention needs to be in the range of 100°C or higher and 145°C or lower, preferably 110°C or higher and 140°C or lower, more preferably 120°C or higher and 130°C or lower. When the glass transition temperature is higher than the above range, it is necessary to increase the thermoforming temperature, and the thermal radical polymerization of the layer (layer C) formed from the uncured product of the acrylate-based active energy ray curable resin composition (composition C) starts due to the heat during thermoforming, resulting in appearance defects such as cracks after forming. Also, when the glass transition temperature is lower than the above range, the molding temperature appropriate for thermoforming the A layer falls below the glass transition temperature of the layer (layer B) containing the acrylic resin or the layer (layer C) formed from the uncured product of the acrylate-based active energy ray curable resin composition (composition C), and thermoforming becomes impossible. Here, the glass transition point refers to the value measured by the differential scanning calorimetry (DSC) method.

[0030] The method for adjusting the glass transition temperature of the A layer is not particularly limited, but in order to ensure the transparency of the thermoforming sheet, a method of blending a polyester-based thermoplastic elastomer with the polycarbonate resin is preferred. Further, the polyester-based thermoplastic elastomer is preferably a multi-block copolymer composed of a hard segment made of polybutylene terephthalate units and a soft segment made of polyester units having an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid as the dicarboxylic acid component and a diol having 5 to 15 carbon atoms as the diol component.

[0031] The hard segment composed of polybutylene terephthalate units has excellent compatibility with polycarbonate resin, is preferable in terms of transparency and thermoformability, and also has good properties in terms of strength and the like. Polybutylene terephthalate may contain other components as copolymerization components as long as the effects of the present invention are not impaired. The ratio of such copolymerization components is preferably 30 mol% or less, more preferably 20 mol% or less, and even more preferably 10 mol% or less in 100 mol% of the total components of both the dicarboxylic acid component and the diol component. The intrinsic viscosity of the polymer serving as the hard segment is preferably in the range of 0.2 to 2.0, more preferably 0.5 to 1.5.

[0032] The soft segment composed of polyester units having the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid as the dicarboxylic acid component and a diol having 5 to 15 carbon atoms as the diol component means a segment in which the melting point of the polymer formed from the segment is 100°C or lower, or which is liquid and amorphous at 100°C. The intrinsic viscosity of the polymer serving as the soft segment is preferably in the range of 0.2 to 2.0, more preferably 0.5 to 1.5. The soft segment used is a soft segment composed of polyester units having an aromatic dicarboxylic acid and / or an aliphatic carboxylic acid as the dicarboxylic acid component and a diol having 5 to 15 carbon atoms as the diol component. (Hereinafter, it may be referred to as "SS-1" in some cases). SS-1 is suitable because extremely good transparency can be obtained.

[0033] In the soft segment SS-1, the content of the aromatic dicarboxylic acid is preferably 60 to 99 mol% and the content of the aliphatic dicarboxylic acid is preferably 1 to 40 mol% in 100 mol% of the total dicarboxylic acid components in terms of obtaining better transparency. More preferably, the content of the aromatic dicarboxylic acid is 70 to 95 mol% and the content of the aliphatic dicarboxylic acid is 5 to 30 mol%. Even more preferably, the content of the aromatic dicarboxylic acid is 85 to 93 mol% and the content of the aliphatic dicarboxylic acid is 7 to 15 mol%. Particularly preferably, the content of the aromatic dicarboxylic acid is 89 to 92 mol% and the content of the aliphatic dicarboxylic acid is 8 to 11 mol%.

[0034] As the aromatic dicarboxylic acid of SS-1, at least one selected from the group consisting of terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenylcarboxylic acid, bis(4-carboxyphenyl)methane, and bis(4-carboxyphenyl)sulfone is preferably used. Terephthalic acid and isophthalic acid are more preferable, and isophthalic acid is particularly preferable from the viewpoint of reducing crystallinity.

[0035] As the aliphatic dicarboxylic acid of SS-1, linear aliphatic dicarboxylic acids having 4 to 12 carbon atoms such as succinic acid, adipic acid, and sebacic acid are preferable, and sebacic acid is particularly preferable.

[0036] As the diol component having 5 to 15 carbon atoms of SS-1, linear aliphatic diols having 6 to 12 carbon atoms such as hexamethylene glycol, decamethylene glycol, 3-methylpentanediol, and 2-methyloctamethylene diol are more preferable, and hexamethylene glycol is particularly preferable.

[0037] SS-1 is particularly preferable from the viewpoints that it has high compatibility with a polycarbonate resin and can provide a product with high transparency, and that the surface properties and transparency after thermoforming are also good. More specifically, as SS-1, a polyester composed of isophthalic acid, sebacic acid, and hexamethylene glycol is preferable.

[0038] In the present invention, the ratio of the hard segment to the soft segment in the polyester-based thermoplastic elastomer is preferably such that the hard segment is 20 to 70% by weight and the soft segment is 80 to 30% by weight in 100% by weight of the elastomer, and more preferably the hard segment is 20 to 40% by weight and the soft segment is 80 to 60% by weight. The intrinsic viscosity of the polyester-based thermoplastic elastomer (value measured at 35 °C in o-chlorophenol) is preferably 0.6 or more, more preferably in the range of 0.8 to 1.5, and even more preferably in the range of 0.8 to 1.2. If the intrinsic viscosity is lower than the above range, the sheet strength may decrease, which is not preferable.

[0039] In the present invention, it is preferable to contain 1 to 20 parts by weight of the polyester-based thermoplastic elastomer with respect to 100 parts by weight of the polycarbonate-based resin in the A layer. If the polyester-based thermoplastic elastomer is less than 1 part by weight, the glass transition temperature of the A layer may exceed 145 °C, and if it exceeds 20 parts by weight, the glass transition temperature of the A layer may fall below 100 °C.

[0040] The thickness of the A layer is preferably in the range of 50 to 3000 μm, more preferably in the range of 100 to 2000 μm, even more preferably in the range of 150 to 1500 μm, particularly preferably in the range of 200 to 1000 μm, and most preferably in the range of 250 to 500 μm.

[0041] The A layer of the present invention may contain various additives generally used in each resin. For example, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, dyes, etc. may be mentioned. Further, within a range not impairing the effects of the present invention, reinforcing fillers such as glass fibers may be contained.

[0042] (Layer containing acrylic resin (B layer)) In the present invention, the acrylic resin used for the B layer is preferably mainly composed of a polymer of a methacrylic acid ester or an acrylic acid ester. When a resin other than the acrylic resin is used for the B layer, for example, in the case of a polycarbonate resin, the surface hardness of the laminated film is low, and the molded body is likely to be scratched, which is not preferable. Further, in the case of a PET resin, appearance defects due to uneven thickness are likely to occur, which is not preferable. As the acrylic resin, a copolymer containing preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, and particularly preferably 90 mol% or more of methyl methacrylate is preferable.

[0043] Examples of other copolymerization components include ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc. Further, examples of other copolymerization components include other ethylenically unsaturated monomers. Specifically, vinyl aromatic compounds such as styrene, α-methylstyrene, vinyltoluene, diene compounds such as 1,3-butadiene, isoprene, alkenyl cyanide compounds such as acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, maleic anhydride, N-substituted maleimide, etc. are included. These may be used alone or in combination of two or more. The content of the copolymerization component is preferably 0 to 50% by weight, more preferably 0 to 30% by weight, still more preferably 0 to 20% by weight. The production method of the acrylic resin is generally roughly classified into an emulsion polymerization method, a suspension polymerization method, and a continuous polymerization method, but the acrylic resin used in the present invention may be produced by any polymerization method. Further, various additives such as a general heat stabilizer, a coloring agent, a release agent, a lubricant, an antistatic agent, a matting agent, etc. may be added to the B layer.

[0044] Rubber particles can be added to the B layer of the present invention, but it is preferably substantially free of rubber particles. Although improving toughness by adding rubber particles to an acrylic resin is a known technique and is widely used, it is preferably not included from the viewpoints of ensuring transparency and surface hardness.

[0045] The thickness of the B layer is preferably in the range of 10 to 300 μm, more preferably in the range of 20 to 250 μm, still more preferably in the range of 30 to 200 μm, particularly preferably in the range of 35 to 150 μm, and most preferably in the range of 40 to 100 μm.

[0046] (Layer (C layer) formed from the uncured product of the acrylate-based active energy ray curable resin composition (Composition C)) The uncured product of the active energy ray curable resin composition (Composition C) constituting the C layer of the present invention contains an acrylate-based resin such as acrylate or urethane acrylate. Its content is preferably in the range of 70 to 95% by mass in the total solid content of the C layer. If it is less than 70% by mass, the cohesive force, chemical resistance, abrasion resistance, optical properties, etc. of the coating film may decrease. If it exceeds 95% by mass, the initiation of photopolymerization may be delayed, resulting in inferior productivity.

[0047] The acrylate-based resin contained in the C layer in the present invention may be either an oligomer or a prepolymer, and is not particularly limited.

[0048] The glass transition temperature of the uncured product of the acrylate-based resin composition (Composition C) is preferably 30 to 150 °C, more preferably 35 to 140 °C, and particularly preferably 40 to 130 °C. When using an acrylate-based resin with a glass transition temperature of less than 30 °C, the coating film after heat drying in the uncured state has tackiness, and blocking is likely to occur during roll winding. If the glass transition point exceeds 150 °C, sufficient heat is not applied during molding, and cracking may occur.

[0049] In addition, the pencil hardness of the cured layer after irradiating the uncured product of the acrylate-based resin composition (Composition C) with active energy rays such as ultraviolet rays and curing is preferably H or higher. By setting the pencil hardness within this range, there is the merit of improving abrasion resistance. When the pencil hardness is H or higher, the abrasion resistance is sufficient.

[0050] Here, as will be described later in the examples, the pencil hardness refers to a value obtained by coating and drying an uncured acrylate resin composition (Composition C) to form a sheet, irradiating the sheet with ultraviolet light at an integrated light quantity of 1000 mJ / cm 2 to cure the coating film to obtain a test piece, and measuring the pencil hardness of the coating film in accordance with JIS K5600-5-4-1999.

[0051] In the present invention, a photoinitiator can be contained in the C layer. By containing a photoinitiator, the polymerization curing reaction of the hard coat layer by light (ultraviolet light) irradiation can be carried out in a short time. Examples of the photoinitiator include benzophenone, benzyl, Michler's ketone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-diethoxyacetophenone, benzyldimethyl ketal, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyr-1-yl)titanium, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and the like. Further, these compounds may be used alone or in combination of a plurality thereof.

[0052] The photoinitiator contained in the solid content of the C layer is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, based on the total solid content of the C layer. If the content of the photoinitiator is less than 0.01% by mass, the photocurability may decrease. If the content exceeds 10% by mass, coloring of the C layer may occur, and since the progress of the photocuring reaction does not change, it may be economically disadvantageous. In addition, various known dyes and sensitizers can be added to improve the photocurability.

[0053] The thickness of the C layer is preferably in the range of 1 to 50 μm, more preferably in the range of 2 to 30 μm, even more preferably in the range of 2.5 to 20 μm, and particularly preferably in the range of 3 to 10 μm.

[0054] Surfactants such as leveling agents, defoaming agents, and antifouling agents, additives such as surface modifiers, and fillers such as organic fillers and inorganic fillers can be added to the C layer according to the situation.

[0055] (hindered amine compound) The C layer of the present invention preferably contains a hindered amine compound. By containing a hindered amine compound, heat radicals generated by heat during thermoforming can be captured, and thermal radical polymerization can be suppressed. Further, from the viewpoint of effectively exerting the effects of the present invention, the content of the hindered amine compound is preferably 1 to 5 parts by weight with respect to 100 parts by weight of the uncured product of the acrylate-based active energy ray curable resin composition (composition C). If the content is less than 1 part by weight, the heat radical capturing effect may not be obtained, and if it exceeds 5 parts by weight, curing inhibition of the C layer may be caused.

[0056] (protective film) It is preferable to laminate a protective film on the surface of the C layer in order to protect the uncured and uncrosslinked C layer before curing of the thermoforming sheet of the present invention from contamination and damage. The protective film is not particularly limited, but polyethylene films, polypropylene films, polyethylene terephthalate films, etc. can be preferably used. Considering the heat applied in the step of forming a decorative layer on the side of the A layer of the thermoforming sheet of the present invention opposite to the B layer and the C layer side by printing or the like after laminating the protective film, heat-resistant polypropylene films and polyethylene terephthalate films are more preferable.

[0057] (Method for manufacturing a thermoforming sheet) The laminated sheet of the A layer and the B layer constituting the thermoforming sheet of the present invention can be manufactured by a coextrusion method using the molding material A for the A layer and the molding material B for the B layer. The coextrusion method is a method of obtaining a multilayer sheet by melt-extruding the molding material A and the molding material B using separate extruders and laminating them using a feed block or a multi-manifold die. By adjusting the extrusion amount, film-forming speed, die lip interval, etc. of each extruder, it is possible to control the total thickness and thickness composition of the obtained laminated sheet.

[0058] The laminated sheet is formed into a sheet by bringing the molten resin into close contact with a roll or a belt. Furthermore, since the molten resin before cooling and solidifying can be narrowly pressed with a metal roll to transfer a metal mirror surface, the surface appearance of the laminated sheet can be improved. Examples of the metal elastic roll include a shaft roll and a cylindrical metal thin film disposed so as to cover the outer peripheral surface of the shaft roll and contacting the molten resin, and those in which a temperature-controlled fluid such as water or oil is enclosed between the shaft roll and the metal thin film, and those in which a metal belt is wound around the surface of a rubber roll. Among them, a metal elastic roll with a metal belt wound around two or more rolls can cool the molten resin with as little stress remaining in the resin as possible by narrowly pressing it on a wider surface on the arc.

[0059] In order to laminate the C layer constituting the sheet for thermoforming of the present invention on the laminated sheet of the A layer and the B layer, a coating method is generally used. The coating method is not particularly limited, but coating can be performed by a method in which the coating film thickness can be easily adjusted, such as gravure coating, microgravure coating, fountain coating, slide die coating, slot die coating, etc. In the coating step, a coating material in which an acrylate-based active energy ray curable resin composition (Composition C) and, if necessary, a hindered amine compound, an initiator, and other additives are dissolved and dispersed in an appropriate solvent is coated on the laminated sheet and dried to form the C layer. The solvent can be appropriately selected according to the solubility of Composition C, and any solvent that can uniformly dissolve or disperse at least the solid content (resin, polymerization initiator, and other additives) may be used. Examples of such solvents include ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ethers (dioxane, tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated carbons (dichloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), alcohols (methanol, ethanol, isopropanol, butanol, cyclohexanol, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetates, sulfoxides, amides, and the like. Further, the solvents may be used alone or in combination.

[0060] The thickness of the sheet for thermoforming of the present invention is not particularly limited, but is preferably 0.05 mm or more and 3 mm or less, more preferably 0.1 mm or more and 2.5 mm or less, still more preferably 0.15 mm or more and 2 mm or less, and particularly preferably 0.2 mm or more and 1 mm or less.

[0061] (Method for manufacturing a decorative sheet) In the thermoforming sheet of the present invention, a decorative layer by printing or the like can be provided on the side of the A layer opposite to the B layer. Examples of the method for forming the decorative layer include forming a pattern layer by printing, forming a thin film layer of a metal or a metal oxide, etc., and these may be used in combination. As the printing method for forming the pattern layer, known printing methods such as gravure printing, offset printing, flexographic printing, dry offset printing, pad printing, and screen printing can be used according to the product shape and printing purpose. Examples of the method for forming a thin film layer of a metal or a metal oxide include vapor deposition, spraying method, plating method, etc. Specifically, as the vapor deposition method, methods such as vacuum vapor deposition, sputtering, ion plating, thermal CVD method, plasma CVD method, and photo CVD method can be mentioned. Also, as the spraying method, atmospheric pressure plasma spraying method, reduced pressure plasma spraying method, etc. can be mentioned. As the plating method, electroless plating method, molten plating method, electroplating method, etc. can be mentioned.

[0062] In addition, in the thermoforming sheet and the decorative sheet, it is preferable that the C layer be the outermost layer because of excellent properties such as hardness.

[0063] (Method for manufacturing a molded body) Using the thermoforming sheet or the decorative sheet of the present invention, a molded body can be created. Examples of the molded body include automotive interior materials, automotive indicator panels, electric appliances, cosmetic cases, building interior and exterior products, cases for various devices, products and sundries, switches, keys, key pads, handles, levers, buttons, housings and exterior parts of personal computers, mobile phones and mobile devices which are home appliances and AV devices, etc.

[0064] The molded body can be obtained by performing various conventionally known moldings using the thermoforming sheet or the decorative sheet.

[0065] As a method for forming a molded body, an in-mold decoration method in injection molding is used. A thermoforming sheet or a decorative sheet pre-shaped by vacuum forming, pressure-air forming, etc. along the shape of the injection mold cavity is set in the mold, and molten resin is injected there. At the same time as injection molding, the thermoforming sheet or the decorative sheet is welded to the resin molded product to be integrated to obtain a molded body, which is called an insert molding method.

[0066] Also, as another method for forming a molded body, a thermoforming sheet or a decorative sheet is attached to the mold cavity side by vacuum pressure, and molten resin is injected there. By applying heat and pressure, the thermoforming sheet or the decorative sheet is bonded to the resin molded product to obtain a molded body, which is called a molding method.

[0067] Furthermore, a method of laminating by vacuum forming or pressure-air forming is included. As a heating method for the decorative film for decorative molding during thermoforming, various methods such as an infrared heater, an electric heater, high-frequency induction, a halogen lamp, a microwave, a high-temperature conductor (such as steam), and a laser can be used.

[0068] It is preferable that the C layer is located on the outermost surface of the molded body in the created molded body. The molded body is cooled or allowed to cool, and then the C layer is cured by irradiating with radiation (ultraviolet rays, visible light, infrared rays, or electron beams). These radiations may be polarized or unpolarized. In particular, ultraviolet rays are preferable from the viewpoints of equipment cost, safety, running cost, etc. When curing by ultraviolet irradiation, it is necessary to add a photoinitiator. As an energy source of ultraviolet rays, for example, a high-pressure mercury lamp, a halogen lamp, a xenon lamp, a metal halide lamp, a nitrogen laser, an electron beam accelerator, a radioactive element, etc. are preferable. The irradiation amount of the energy source is preferably in the range of 100 to 5,000 mJ / cm 2 in terms of the integrated exposure amount at an ultraviolet wavelength of 365 nm, and more preferably 300 to 3,000 mJ / cm 2 If the irradiation amount is less than 100 mJ / cm 2 , the curing may be insufficient and the hardness may decrease. Also, if it is 5,000 mJ / cm 2When it exceeds this value, the C layer may be colored and the transparency may decrease. The oxygen concentration during radiation irradiation is preferably 5% or less, more preferably 3% or less, and particularly preferably 2% or less. For an oxygen-free or low-concentration atmosphere, the gas contained in addition to oxygen is preferably an inert gas. Examples of the inert gas include nitrogen, helium, neon, argon, and the like.

Examples

[0069] The present invention will be described more specifically by way of examples below, but the present invention is not limited to only these examples. The physical property measurements performed in the examples and comparative examples were carried out by the following methods. (Glass transition temperature) Using a 2920-type DSC manufactured by TA Instruments, the measurement was carried out at a heating rate of 20 °C / min, and the inflection point was determined. (Total thickness of the thermoforming sheet) It is the value at the center in the sheet width direction measured with an electronic micrometer film thickness gauge manufactured by Anritsu Corporation. The sheet width direction represents the direction perpendicular to the sheet flow direction during film formation. (Pencil hardness) From the C layer side of the prepared thermoforming sheet, the ultraviolet rays were irradiated with an integrated light amount of 1000 mJ / cm 2 to cure the coating film to obtain a test piece, and the pencil hardness of the coating film was measured in accordance with JIS K5600-5-4-1999. (Formability) Using a biaxial stretching test apparatus (manufactured by Toyo Seiki Co., Ltd.), after preheating the thermoforming sheet at a temperature of (glass transition temperature + 20) °C for 1 minute, the appearance of the sheet when stretched at the same temperature with a stretching ratio of 1.3 times was evaluated according to the following criteria. 〇: No cracks and cloudiness are observed △: Weak cracks or slight cloudiness are observed ×: Cracks or cloudiness are observed

[0070] [Preparation Example 1] (Production of polyester-based thermoplastic elastomer) To 100 parts by weight of dimethyl isophthalate, 13 parts by weight of dimethyl sebacate and 80 parts by weight of hexamethylene glycol were subjected to transesterification reaction with a dibutyltin diacetate catalyst, and then polycondensed under reduced pressure to obtain an amorphous polyester (soft segment) having an intrinsic viscosity of 1.06 and showing no endothermic peak due to melting of crystals as measured by the DSC method. To 100 parts by weight of the above polyester, 32 parts by weight of pellets of polybutylene terephthalate having an intrinsic viscosity of 0.98 (hard segment) were added, and after reacting at 240 °C for 45 minutes, 0.03 parts by weight of phenylphosphonic acid was added to stop the reaction. The melting point of the obtained polymer was 190 °C and the intrinsic viscosity was 0.93.

[0071] [Example 1] (Molding Material A) Polycarbonate resin pellets (Panlite L1250WP manufactured by Teijin Limited, a homopolycarbonate resin of bisphenol A (PC-A), viscosity average molecular weight 23,900)), and the thermoplastic elastomer obtained in the above [Preparation Example] were each pre-dried in advance, and mixed with a V-type blender so that the amount of the thermoplastic elastomer was 1 part by weight with respect to 100 parts by weight of the polycarbonate resin pellets, and then extruded at a cylinder temperature of 260 °C using a twin-screw extruder and pelletized to obtain a molding material A for layer A. The glass transition temperature of the molding material A was 145 °C.

[0072] (Molding Material B) As a molding material B for layer B, an acrylic resin (Acrypet VH-001 manufactured by Mitsubishi Rayon Co., Ltd., an acrylic resin copolymerized with 95 mol% of methyl methacrylate and 5 mol% of methyl acrylate) was prepared.

[0073] [Coextrusion] The molding materials A and B were extruded from a T-die with a width of 650 mm by a feed block method using a single-screw extruder with a screw diameter of 40 mm under the conditions of a cylinder temperature of 260 °C (for molding material A), 250 °C (for molding material B), a screw rotation speed of 11 rpm (for molding material A), and 109 rpm (for molding material B). After the molten resin was narrowly pressed and cooled between a metal roll and a metal sleeve roll, it was edge-trimmed and wound up at a winding speed of 10.3 m / min to create a laminated sheet with a width of 400 mm having a two-layer structure of A layer / B layer (A layer: 440 μm, B layer: 60 μm).

[0074] (Paint adjustment) As the paint for forming the C layer, 100 parts by weight of a urethane acrylate-based ultraviolet curable resin "Forside No. 371C (trade name)" (solid content: 40%, manufactured by Nippon Paint Co., Ltd.), 5 parts by weight of Irgacure 184 (photoinitiator, manufactured by Ciba Specialty Chemicals Co., Ltd.), and 5 parts by weight of a hindered amine-based compound "TINUVIN 292 (trade name)" (manufactured by BASF Co., Ltd.) were diluted with methyl isobutyl ketone until the solid content concentration in the paint of the ultraviolet curable resin reached 30% and stirred well to prepare the paint.

[0075] (Coating) The paint for forming the C layer was coated on the B layer side of the laminated sheet of the A layer and the B layer using a bar coater (#8), and dried with hot air in a drying oven at 80 °C for 1 minute to form a C layer with a coating film thickness of 5 μm. Then, a protective film made of polypropylene (manufactured by Oji Efttex Co., Ltd.) was laminated on the C layer to create a thermoforming sheet with a thickness of 0.5 mm. The various evaluation results are shown in Table 1.

[0076] [Example 2] A thermoforming sheet was created in the same manner as in Example 1 except that the content of the polyester-based thermoplastic elastomer, the thickness of the laminated sheet, and the content of the hindered amine compound were changed as shown in Table 1. The various evaluation results are shown in Table 1.

[0077] [Example 3] A thermoforming sheet was prepared in the same manner as in Example 1, except that the content of the polyester-based thermoplastic elastomer, the laminated sheet thickness, and the content of the hindered amine compound were changed as shown in Table 1. The various evaluation results are shown in Table 1.

[0078] [Example 4] A thermoforming sheet was prepared in the same manner as in Example 1, except that the content of the polyester-based thermoplastic elastomer, the laminated sheet thickness, and the content of the hindered amine compound were changed as shown in Table 1. The various evaluation results are shown in Table 1.

[0079] [Example 5] A thermoforming sheet was prepared in the same manner as in Example 1, except that the content of the polyester-based thermoplastic elastomer and the content of the hindered amine compound were changed as shown in Table 1. The various evaluation results are shown in Table 1.

[0080] [Example 6] As the rubber particles in the molding material B, the innermost layer is a hard polymer obtained by polymerization of a monomer consisting of 93.8% methyl methacrylate, 6% methyl acrylate, and 0.2% allyl methacrylate, the intermediate layer is an elastic polymer obtained by polymerization of a monomer consisting of 81% butyl acrylate, 17% styrene, and 2% allyl methacrylate, and the outermost layer is a hard polymer obtained by polymerization of a monomer consisting of 94% methyl methacrylate and 6% methyl acrylate. 5 parts by weight of rubber particles by the emulsion polymerization method were mixed with 100 parts by weight of the acrylic resin. A thermoforming sheet was prepared in the same manner as in Example 1, except that the content of the polyester-based thermoplastic elastomer and the laminated sheet thickness were changed as shown in Table 1. The various evaluation results are shown in Table 1.

[0081] [Example 7] A thermoforming sheet was prepared in the same manner as in Example 1, except that the laminated sheet thickness was changed as shown in Table 1. The various evaluation results are shown in Table 1.

[0082] [Example 8] A thermoformed sheet was produced in the same manner as in Example 1, except that the content of the polyester-based thermoplastic elastomer, the laminated sheet thickness, and the content of the hindered amine compound were changed as shown in Table 1. The various evaluation results are shown in Table 1.

[0083] [Example 9] A thermoformed sheet was produced in the same manner as in Example 1, except that the laminated sheet thickness and the content of the hindered amine compound were changed as shown in Table 1. The various evaluation results are shown in Table 1.

[0084] [Example 10] A thermoformed sheet was produced in the same manner as in Example 1, except that the content of the polyester-based thermoplastic elastomer, the laminated sheet thickness, and the content of the hindered amine compound were changed as shown in Table 1. The various evaluation results are shown in Table 1.

[0085] [Example 11] During the production of the polycarbonate resin pellets of molding material A, 2,2-bis{(4-hydroxy-3-methyl)phenyl}propane (commonly known as bisphenol C; PC-C) was used instead of 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A). Also, a thermoformed sheet was produced in the same manner as in Example 1, except that the content of the polyester-based thermoplastic elastomer, the laminated sheet thickness, and the content of the hindered amine compound were changed as shown in Table 1. The various evaluation results are shown in Table 1.

[0086] [Example 12] After forming the C layer, the protective film was not laminated. Also, a thermoformed sheet was produced in the same manner as in Example 1, except that the content of the polyester-based thermoplastic elastomer, the laminated sheet thickness, and the content of the hindered amine compound were changed as shown in Table 1. The various evaluation results are shown in Table 1.

[0087] [Comparative Example 1] A polyester-based thermoplastic elastomer was not added to molding material A. Also, a thermoformed sheet was produced in the same manner as in Example 1, except that the laminated sheet thickness was changed as shown in Table 1. The various evaluation results are shown in Table 2.

[0088] [Comparative Example 2] A thermoforming sheet was prepared in the same manner as in Example 1, except that the content of the polyester-based thermoplastic elastomer, the laminated sheet thickness, and the content of the hindered amine compound were changed as shown in Table 1. The various evaluation results are shown in Table 2.

[0089] [Comparative Example 3] As the resin composition for forming the C layer, instead of the urethane acrylate-based ultraviolet curable resin "Forcide No. 371C", an isopropanol solution Togasard 510 (manufactured by Momentive Performance Materials Co., Ltd.) mainly composed of trifunctional and tetrafunctional alkoxysilanes was applied, and then dried by hot air in a drying oven at 80 °C for 1 minute. Also, as rubber particles in the molding material B, a hard polymer obtained by polymerization of a monomer composed of 93.8% methyl methacrylate, 6% methyl acrylate, and 0.2% allyl methacrylate for the innermost layer, an elastic polymer obtained by polymerization of a monomer composed of 81% butyl acrylate, 17% styrene, and 2% allyl methacrylate for the intermediate layer, and a hard polymer obtained by polymerization of a monomer composed of 94% methyl methacrylate and 6% methyl acrylate for the outermost layer. Rubber particles obtained by an emulsion polymerization method were mixed in an amount of 5 parts by weight with respect to 100 parts by weight of the acrylic resin. Further, a thermoforming sheet was prepared in the same manner as in Example 1, except that the laminated sheet thickness and the content of the hindered amine compound were changed as shown in Table 1. The various evaluation results are shown in Table 2.

[0090]

Table 1

[0091]

Table 2

Industrial Applicability

[0092] The sheet for thermoforming and the decorative sheet of the present invention are excellent in formability and hardness, and the molded article using the sheet for thermoforming and the decorative sheet is useful as an automotive interior material, an automotive indicator panel, an electric appliance, a cosmetic case, an interior and exterior material for building materials, a case for various devices, products and sundries, a switch, a key, a key pad, a handle, a lever, a button, and a housing and exterior parts of a personal computer, a mobile phone and a mobile device which are home electric appliances and AV devices.

Claims

1. A sheet for thermoforming, which is formed by laminating at least three layers in this order: a layer containing a polycarbonate resin (layer A), a layer containing an acrylic resin (layer B), and a layer (layer C) formed from an uncured product of a urethane acrylate-based active energy ray curable resin composition (composition C). After preliminarily shaping the thermoforming sheet into the shape of the mold cavity, with the glass transition temperature (Tg) of the layer A being 100°C or higher and 145°C or lower, it is placed in the mold and integrated simultaneously with the molding of the resin material to produce a molded body, and then post-exposure with active energy rays is performed. A method for manufacturing a molded body, characterized by this.

2. A decorated sheet for thermoforming, which is formed by laminating at least four layers in this order: a decorative layer, a layer containing a polycarbonate resin (layer A), a layer containing an acrylic resin (layer B), and a layer (layer C) formed from an uncured product of a urethane acrylate-based active energy ray curable resin composition (composition C). After preliminarily shaping the thermoforming sheet into the shape of the mold cavity, with the glass transition temperature (Tg) of the layer A being 100°C or higher and 145°C or lower, it is placed in the mold and integrated simultaneously with the molding of the resin material to produce a molded body, and then post-exposure with active energy rays is performed. A method for manufacturing a molded body, characterized by this.

3. A sheet for thermoforming, which is formed by laminating at least three layers in this order: a layer containing a polycarbonate resin (layer A), a layer containing an acrylic resin (layer B), and a layer (layer C) formed from an uncured product of a urethane acrylate-based active energy ray curable resin composition (composition C). The thermoforming sheet with the glass transition temperature (Tg) of the layer A being 100°C or higher and 145°C or lower is attached to the mold cavity side with a vacuum pressure, and integrated simultaneously with the molding of the resin material to produce a molded body, and then post-exposure with active energy rays is performed. A method for manufacturing a molded body, characterized by this.

4. A decorated sheet for thermoforming, which is formed by laminating at least four layers in this order: a decorative layer, a layer containing a polycarbonate resin (layer A), a layer containing an acrylic resin (layer B), and a layer (layer C) formed from an uncured product of a urethane acrylate-based active energy ray curable resin composition (composition C). The thermoforming sheet with the glass transition temperature (Tg) of the layer A being 100°C or higher and 145°C or lower is attached to the mold cavity side with a vacuum pressure, and integrated simultaneously with the molding of the resin material to produce a molded body, and then post-exposure with active energy rays is performed. A method for manufacturing a molded body, characterized by this.

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