Sheet for thermoforming and decorative sheet

Abstract

Provided is a sheet for thermoforming, which is capable of reducing or suppressing the occurrence of upwarp of a peelable layer when, for example, a functional layer, a design layer or the like is laminated, and which has excellent workability, thermoformability and the like. The sheet for thermoforming according to the present disclosure is a sheet for thermoforming in which at least three layers, i.e., a layer (layer A) comprising a thermoplastic resin, a layer (layer B) comprising an uncured product of a (meth) acrylate-based active energy ray-curable resin composition (composition B), and a layer (layer C) that can be peeled off from the layer B, are laminated in this order, when the elongation of the C layer in the MD direction at 100 DEG C is [beta] 1 (%) and the elongation of the laminate in the MD direction at 100 DEG C after the C layer has been peeled from the sheet for thermoforming is [alpha] 1 (%), [beta] 1-[alpha] 1 is-0.5-5.0%.

Description

Technical Field

[0001] The present invention relates to a sheet for thermoforming and a decorative sheet. Background Art

[0002] In recent years, for example, due to the diversification of automobile designs or the requirement for weight reduction of automobiles, the number of resin molded parts used in automobiles is increasing. These resin molded parts are required to have designs such as wood grain style and metal style, as well as functions such as chemical resistance and scratch resistance.

[0003] In addition, for the casings and front panels of electronic devices and the like, designability and three-dimensional shapes are also required, as well as functions such as chemical resistance and scratch resistance, and resin molded products are preferably used.

[0004] As a method for imparting appearance and function, a method of integrating a sheet having a specific design or function such as a decorative sheet with a resin molded product has been proposed. As specific examples, the following two methods can be exemplified:

[0005] (1) A method in which a sheet is previously formed into a specific shape by thermoforming (vacuum forming, pressure forming, etc.), it is set in an injection molding die, and molten resin is injected to form an injection molded body, and at the same time it is integrated with the preformed sheet.

[0006] (2) A method of coating a sheet on a previously produced resin molded product by thermoforming (three-dimensional surface decoration molding).

[0007] In the methods (1) and (2), thermoforming of the sheet is essential, and in order to have chemical resistance and scratch resistance, the thermoforming sheet used generally has a hard coat.

[0008] For example, Patent Document 1 discloses an insert molding hard coating film having a base film and a hard coat formed on the surface of the base film, the hard coat being composed of a composition cured by ionizing radiation, and the indentation hardness of the hard coat measured by nanoindentation being 10 to 200 N / mm at 30°C 2 , and 100 N / mm or less at 150°C 2 .

[0009] Patent Document 2 discloses a laminated hard coating film for molding, which is a laminated hard coating film for molding in which a hard coat containing resin is provided on a base film, and the laminated hard coating film has an elongation of 10% or more in an atmosphere of 23°C and 50% RH.

[0010] Patent Document 3 discloses a decorative laminated member having, in order, a protective film, a coating layer, and a resin substrate. The protective film has an adhesive layer that contacts the coating layer. The surface roughness Rz(a) of the coating layer side of the adhesive layer in the state where it does not contact the coating layer and the surface roughness Rz(b) of the side of the coating layer of the non-heated specimen of the coating layer and the resin substrate after peeling the protective film in the laminated member from the coating layer at a speed of 5.0 mm / second satisfy the following relationship:

[0011] 85% < Rz(b) / Rz(a)×100 ≤ 110% (1);

[0012] The surface roughness Rz(b) and the surface roughness Rz(bh) of the side of the coating layer of the heated specimen obtained by heating the non-heated specimen in an atmosphere of 150 to 190°C for 30 to 60 seconds satisfy at least one of the following (2) and (3):

[0013] 0% ≤ Rz(bh) / Rz(b)×100 < 30% (2),

[0014] 0 ≤ Rz(bh) ≤ Rz(b) < 0.5 μm (3); and

[0015] The coating layer has unreacted (meth)acryloyl groups. In the state where the heated specimen is irradiated with active energy rays of 500 mJ / cm 2 Compared with the unreacted (meth)acryloyl groups in the above coating layer of the non-heated specimen, 10 to 100% of the unreacted (meth)acryloyl groups in the coating layer disappear.

[0016] Prior Art Documents

[0017] Patent Documents

[0018] Patent Document 1: International Publication No. 2022 / 014674

[0019] Patent Document 2: Japanese Patent Application Laid-Open No. 2012-210755

[0020] Patent Document 3: International Publication No. 2020 / 116576 Summary of the Invention

[0021] When thermoforming a thermoforming sheet having a hard coating into a specified shape, generally, in order to prevent cracks and the like during thermoforming, that is, in order to improve formability, the hard coating is generally formed in an uncured state. The surface of the uncured hard coating is soft and is easily scratched and the like. Therefore, considering operability and the like, a protective film having peelability from the hard coating is generally applied to the thermoforming sheet having the above layers.

[0022] If the adhesion of the protective film to the hard coat is too strong, that is, the peelability of the protective film is too weak, it is impossible to easily peel the protective film from the hard coat. Therefore, the working efficiency may decrease. On the other hand, if the adhesion of the protective film to the hard coat is too weak in order to improve the working efficiency, that is, the peelability of the protective film is too high, for example, when laminating a functional layer, a design layer, etc., the protective film may partially peel from the hard coat, resulting in a state where the protective film warps from the hard coat. Such warping of the protective film sometimes deteriorates the appearance of the molded product produced by applying the thermoforming sheet at the time of shipment, or in a state where the protective film has warped, for example, when the protective film is peeled off after laminating a functional layer, a design layer, etc. and performing heat treatment, appearance defects such as wrinkles or scratches corresponding to the warped portion of the protective film are generated on the surface of the hard coat.

[0023] Therefore, an object of the present disclosure is to provide a thermoforming sheet that can reduce or suppress the generation of warping of a peelable layer when laminating a functional layer, a design layer, etc., and has excellent workability and thermoformability.

[0024] <Mode 1>

[0025] A thermoforming sheet is formed by laminating at least three layers including a layer containing a thermoplastic resin (layer A), a layer formed of an uncured product of a (meth)acrylate-based active energy ray curable resin composition (composition B) (layer B), and a layer (layer C) that can be peeled from the layer B in this order.

[0026] When the elongation at break in the MD direction of the layer C at 100 °C is β1 (%), and the elongation at break in the MD direction of the laminate after peeling the layer C from the thermoforming sheet at 100 °C is α1 (%), β1 - α1 is -0.5% to 5.0%.

[0027] <Mode 2>

[0028] The thermoforming sheet according to Mode 1, wherein when the elongation at break in the TD direction of the layer C at 100 °C is β2 (%), β1 - β2 is -2.0% to 4.0%.

[0029] <Mode 3>

[0030] The thermoforming sheet according to Mode 1 or 2, wherein the layer C includes an unstretched thermoplastic resin layer or a biaxially stretched thermoplastic resin layer.

[0031] <Mode 4>

[0032] The thermoforming sheet according to any one of Modes 1 to 3, wherein the peel force of the layer C from the layer B is 10 mN / 25 mm to 1000 mN / 25 mm.

[0033] <Mode 5>

[0034] The thermoforming sheet according to any one of Methods 1 to 4, wherein the protrusion defects having a height of 5 μm or more and an area of 0.1 mm 2 or more on the surface of the C layer on the B layer side are 10 pieces / m 2 or less.

[0035] <Method 6>

[0036] The thermoforming sheet according to any one of Methods 1 to 5, wherein the surface roughness (Sa) of the surface of the C layer on the B layer side is 150 nm or less.

[0037] <Method 7>

[0038] The thermoforming sheet according to any one of Methods 1 to 6, wherein the reaction rate of the (meth)acrylate contained in the B layer is 2% to 50%.

[0039] <Method 8>

[0040] The thermoforming sheet according to any one of Methods 1 to 7, wherein the C layer contains at least one resin selected from polycarbonate-based resins, polypropylene, and modified polyolefin-based resins.

[0041] <Method 9>

[0042] The thermoforming sheet according to any one of Methods 1 to 8, wherein the A layer contains a polycarbonate-based resin.

[0043] <Method 10>

[0044] The thermoforming sheet according to Method 9, wherein in the A layer, 1 to 20 parts by mass of a polyester-based thermoplastic elastomer is contained relative to 100 parts by mass of the polycarbonate-based resin.

[0045] <Method 11>

[0046] The thermoforming sheet according to any one of Methods 1 to 10, wherein a layer (D layer) containing a (meth)acrylic resin is provided between the A layer and the B layer.

[0047] <Method 12>

[0048] A decorative sheet having a design layer on the surface of the A layer of the thermoforming sheet according to any one of Methods 1 to 11, which is opposite to the B layer.

[0049] According to the present disclosure, it is possible to provide a thermoforming sheet that can reduce or suppress the generation of warping of a peelable layer when laminating functional layers, design layers, etc., and has excellent workability and thermoformability. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is a cross-sectional view of a sheet for thermoforming according to an embodiment of the present disclosure Detailed Embodiment

[0051] Hereinafter, embodiments of the present disclosure will be described in detail. The present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the invention for implementation.

[0052] The sheet for thermoforming of the present disclosure is composed of laminating at least three layers including a layer containing a thermoplastic resin (layer A), a layer (layer B) formed of an uncured product of a (meth)acrylate-based active energy ray curable resin composition (composition B), and a layer (layer C, sometimes referred to as a "peelable layer") that can be peeled from layer B in this order. When the elongation rate in the MD direction of layer C at 100 °C is set as β1 (%) and the elongation rate in the MD direction of the laminate after peeling layer C from the sheet for thermoforming at 100 °C is set as α1 (%), β1 - α1 is -0.5% to 5.0%. It should be noted that in the present disclosure, the "elongation rate in the MD direction at 100 °C" and the "elongation rate in the TD direction at 100 °C" respectively refer to the length change rates in the MD direction and TD direction when each layer is heated from room temperature (25 °C) to 100 °C.

[0053] Although not limited by the principle, the principle of the sheet for thermoforming of the present disclosure that can reduce or suppress the generation of warping of the peelable layer (layer C) and has excellent workability and thermoformability is considered as follows.

[0054] In order to enable the peelable layer to be peeled from layer B, as Figure 1 shown, the surface (109) on the layer B (103) side of the layer C (105) serving as the peelable layer exhibits peelability. If the peelability of this surface is improved, the peelable layer can be easily peeled from layer B, and the workability can be improved. On the other hand, such a peelable layer may also be peeled from layer B due to deformation stress applied during heat treatment or the like, and a gap is formed between the layer C (105) serving as the peelable layer and layer B. Therefore, it is considered that a warping portion such as warping of the peelable layer (layer C) will be generated. And it is considered that such a warping portion of the peelable layer may sometimes further cause appearance defects such as scratches or wrinkles on the surface of the cured layer. That is, it is considered that such appearance defects are generated as a result of layer B being cured in a state where the uncured layer deforms following the gap of the warping portion of the peelable layer.

[0055] The inventors of the present invention predicted that the stress difference generated between the peelable layer and the uncured layer during heat treatment or the like was due to the generation of the warped portion of the peelable layer, and conducted in-depth research. As a result, it was found that, for example, in the case of laminating a functional layer, a design layer, etc. and performing heat treatment, if the difference in the elongation rate accompanying the thermal expansion of the peelable layer and the elongation rate accompanying the thermal expansion of the laminate other than the peelable layer in the thermoforming sheet with respect to the temperature applied at this time (a temperature of about 100 °C) was small, the generation of the warped portion of the peelable layer could be reduced or suppressed. It is considered that this is because the elongation accompanying the thermal expansion of the peelable layer and the elongation accompanying the thermal expansion of the laminate other than the peelable layer are of the same degree, and in the case of laminating a functional layer, a design layer, etc. and performing heat treatment or the like, the two elongate equally, and as a result, the stress difference generated between the peelable layer and the uncured layer is reduced.

[0056] Therefore, it is considered that even if the thermoforming sheet of the present disclosure uses a peelable layer having excellent peelability, for example, during the operation of the sheet, and when laminating a functional layer, a design layer, etc. and performing heat treatment, the generation of the warped portion of the peelable layer can be reduced or suppressed. Therefore, the operability in the uncured state is improved, and both formability and excellent appearance can be achieved.

[0057] The definitions of the terms in the present disclosure are as follows.

[0058] In the present disclosure, "in sequence" means that when focusing on three constituent members, namely, layer A, layer B, and layer C, the thermoforming sheet includes these constituent members in sequence, and between these constituent members, for example, other layers such as a layer (layer D) containing a (meth)acrylic resin may be interposed between layer A and layer B.

[0059] In the present disclosure, "(meth)acrylic acid" means acrylic acid or methacrylic acid, and "(meth)acrylate" means acrylate or methacrylate.

[0060] "Thermoforming Sheet"

[0061] The thermoforming sheet of the present disclosure, for example Figure 1 as shown, includes at least three layers in sequence: a layer (101 (layer A)) containing a thermoplastic resin, a layer (103 (layer B)) formed from an uncured product of a (meth)acrylate-based active energy ray curable resin composition (composition B), and a layer (105 (layer C)) that can be peeled from layer B.

[0062] First, each layer constituting the thermoforming sheet of the present disclosure will be described below.

[0063] 〈Layer Containing Thermoplastic Resin (Layer A)〉

[0064] The sheet for thermoforming of the present disclosure includes a layer containing a thermoplastic resin (layer A). This layer can be a single layer, or can also be a laminate structure of two or more layers. In the case where layer A is a structure of two or more layers, in order to distinguish each layer in layer A, it can be called layer A1, layer A2, etc.

[0065] There is no particular limitation on the thermoplastic resin. For example, polyolefin resins such as polyethylene, polypropylene, and poly(4-methylpentene-1) can be cited; cycloolefins such as norbornene-based ring-opening metathesis polymers, addition polymers, and addition copolymers with other olefins; biodegradable polymers such as polylactic acid and polybutylene succinate; polyamide resins such as nylon 6, 11, 12, and 66 (including semi-aromatic polyamides); polymethyl methacrylate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, ethylene-vinyl acetate copolymer, polyacetal, polyglycolic acid, polystyrene, styrene copolymerized with polymethyl methacrylate, polycarbonate-based resins, polypropylene terephthalate, polyethylene terephthalate (PET), poly(ethylene isophthalate) (IAPET), polybutylene terephthalate (PBT), poly(ethylene 2,6-naphthalate) (PEN), etc. polyester resins; polyether sulfone, polyether ketone, modified polyphenylene ether, polyphenylene sulfide, polyetherimide, polyimide, polyarylate, tetrafluoroethylene-hexafluoropropylene copolymer, polyvinylidene fluoride, and acrylonitrile-butadiene-styrene copolymer. The thermoplastic resin can be used alone or in combination of two or more.

[0066] Among them, from the viewpoints of thermoformability, the effect of suppressing the warping part of the peelable layer, etc., the layer containing a thermoplastic resin (layer A) preferably contains a polycarbonate-based resin.

[0067] The polycarbonate-based resin used in layer A is a polymer formed by bonding dihydroxy compounds through carbonate bonds, and is usually obtained by reacting a dihydroxy component with a carbonate precursor by an interfacial polymerization method or a melt polymerization method.

[0068] As representative examples of the dihydroxy component, 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

[0069] -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, and 1,6-hexanediol. It may be a homopolymer using them alone or a copolymer formed by copolymerizing two or more of them. From the viewpoints of physical properties and cost, bisphenol A is preferred. In the present disclosure, 50 mol% or more of the bisphenol component is preferably a polycarbonate of bisphenol A and / or bisphenol C, more preferably 70 mol% or more, and still more preferably 90 mol% or more.

[0070] As specific polycarbonates, for example, 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, and a binary copolymer of bisphenol A and 9,9-bis{(4-hydroxy-3

[0071] -methyl)phenyl}fluorene can be cited. A homopolymer of bisphenol A is most preferred.

[0072] As a carbonate precursor, for example, carbonyl halide, carbonate, or haloformate can be used. Specifically, for example, phosgene, diphenyl carbonate, or a dihaloformate of a diphenol can be cited.

[0073] When producing a polycarbonate resin by reacting the above divalent dihydroxy compound with a carbonate precursor by an interfacial polymerization method or a melt polymerization method, for example, a catalyst, a capping agent, and an antioxidant such as a diphenol can also be used as needed. The polycarbonate resin may be a branched polycarbonate resin copolymerized with a polyfunctional aromatic compound having three or more functional groups, or may be a polyester carbonate resin copolymerized with an aromatic or aliphatic difunctional carboxylic acid, or may be a mixture of two or more of the obtained polycarbonate resins.

[0074] The molecular weight of the polycarbonate-based resin is preferably in the range of 13,000 to 40,000 in terms of the viscosity-average molecular weight. If it is in this range, defects such as cracks and burrs during thermoforming can be appropriately suppressed, and melt film formation can be appropriately carried out. 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. In the case where the polycarbonate resin is a mixture of two or more, the molecular weight of the entire mixture is represented. Here, the viscosity-average molecular weight means the specific viscosity (ηsp ) and calculate the viscosity-average molecular weight (M) according to the following formulas (1) and (2):

[0075] η sp / c = [η] + 0.45 × [η] 2 c…Formula (1)

[0076] [η] = 1.23 × 10 －4 m 0.83 …Formula (2)

[0077] (wherein, c = 0.7 g / dL, and [η] is the limiting viscosity)

[0078] From the viewpoints such as thermoformability, etc., the glass transition temperature (Tg) of the layer (layer A) containing a polycarbonate resin is preferably in the range of 100°C to 145°C. The glass transition temperature of this layer is more preferably in the range of 110°C to 140°C, and particularly preferably in the range of 120°C to 130°C. Here, the glass transition temperature refers to the value measured by differential scanning calorimetry (DSC) method.

[0079] The method for adjusting the glass transition temperature of this layer A is not particularly limited. In order to ensure the transparency of the thermoforming sheet, a method of blending a polyester thermoplastic elastomer in the polycarbonate resin is preferred. In addition, this polyester thermoplastic elastomer is preferably a multi-block copolymer composed of a hard segment composed of polybutylene terephthalate units and a soft segment composed of polyester units composed of 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.

[0080] From the viewpoints of excellent compatibility with the polycarbonate resin, transparency, thermoformability, etc., a hard segment composed of the polybutylene terephthalate units is preferred, and good characteristics can also be exhibited from the aspects of strength, etc. Polybutylene terephthalate may also contain other components as copolymer components within the range that does not impair the effects of the present disclosure. Regarding the proportion of this copolymer component, both the dicarboxylic acid component and the diol component are preferably 30 mol% or less, more preferably 20 mol% or less, and further preferably 10 mol% or less in 100 mol% of all their respective components. The intrinsic viscosity of the polymer as the hard segment is preferably in the range of 0.2 to 2.0, and more preferably in the range of 0.5 to 1.5.

[0081] The soft segment composed of a polyester having an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid as the dicarboxylic acid components 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 by this segment is 100°C or lower, or is liquid at 100°C and shows amorphous properties. The intrinsic viscosity of the polymer as the soft segment is preferably in the range of 0.2 to 2.0, more preferably in the range of 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 components and a diol having 5 to 15 carbon atoms as the diol component (hereinafter sometimes referred to as "SS-1"). From the aspect of obtaining excellent transparency, SS-1 is preferred.

[0082] In the soft segment SS-1, from the viewpoint of obtaining better transparency, in 100 mol% of the total dicarboxylic acid components, 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%. 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%. Further 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%.

[0083] As the aromatic dicarboxylic acid of SS-1, at least one selected from 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 preferred, more preferably terephthalic acid and isophthalic acid, and particularly preferably isophthalic acid from the viewpoint of reducing crystallinity.

[0084] 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 preferred, and sebacic acid is particularly preferred.

[0085] 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-methyloctanediol are more preferred, and hexamethylene glycol is particularly preferred.

[0086] SS-1 has high compatibility with the polycarbonate resin and can obtain a substance with high transparency. It is particularly preferred from the viewpoint of good surface properties and transparency after thermoforming. More specifically, as SS-1, a polyester composed of isophthalic acid, sebacic acid, and hexamethylene glycol is preferred.

[0087] In the present disclosure, in the polyester-based thermoplastic elastomer, the ratio of the hard segment to the soft segment is preferably 20 to 70% by mass for the hard segment and 80 to 30% by mass for the soft segment, more preferably 20 to 40% by mass for the hard segment and 80 to 60% by mass for the soft segment in 100% by mass of the elastomer. From the viewpoint of sheet strength, the intrinsic viscosity of the polyester-based thermoplastic elastomer is preferably 0.6 or more, more preferably in the range of 0.8 to 1.5, and further preferably in the range of 0.8 to 1.2. Here, the intrinsic viscosity refers to the value measured in o-chlorophenol at 35°C.

[0088] The glass transition temperature of the A layer can be set within an appropriate range, and as a result, thermoformability can be improved. Therefore, the polyester-based thermoplastic elastomer is preferably contained in the A layer in a range of 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more and 20 parts by mass or less, 18 parts by mass or less, or 15 parts by mass or less with respect to 100 parts by mass of the polycarbonate-based resin in the A layer.

[0089] The thickness of the A layer is not particularly limited and can be appropriately set according to the use purpose of the thermoforming sheet, etc. For example, from the viewpoints of thermoformability, etc., the thickness of the A layer is preferably in the range of 20 to 3000 μm, more preferably in the range of 30 to 2500 μm, further preferably in the range of 40 to 2000 μm, particularly preferably in the range of 50 to 1500 μm, and most preferably in the range of 100 to 1000 μm.

[0090] For the thermoforming sheet of the present disclosure, when the elongation at break in the MD direction of the peelable layer (C layer) described later at 100°C is β1 (%), and the elongation at break in the MD direction of the laminate after peeling the C layer from the thermoforming sheet at 100°C is α1 (%), β1 - α1 needs to be in the range of -0.5% to 5.0%. As long as this condition is satisfied, the elongation at break in the MD direction and / or TD direction of the A layer at 100°C is not particularly limited. As this elongation at break, for example, it can be 0% or more, greater than 0%, 0.1% or more, 0.3% or more, 0.5% or more, 0.7% or more, or 1.0% or more, and can be 10% or less, 8.0% or less, 6.0% or less, 5.0% or less, 3.0% or less, or 1.0% or less. It should be noted that the elongation at break in the present disclosure can be obtained by the method described in the examples below.

[0091] The A layer of the present disclosure can be appropriately blended with various components within a range that does not affect the effects of the present disclosure. As such optional components, for example, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, dyes, pigments, and reinforcing fillers (such as glass fibers) can be cited. These components can be used alone or in combination of two or more.

[0092] (Layer (layer B) formed from the uncured product of a (meth)acrylate-based energy ray curable resin composition (composition B))

[0093] The uncured product of the (meth)acrylate-based energy ray curable resin composition (composition B) that constitutes layer B of the thermoformable sheet of the present disclosure contains a (meth)acrylate-based resin such as a (meth)acrylate or a polyurethane (meth)acrylate. Its content is preferably in the range of 70 to 95% by mass in all solid components of layer B. If it is in such a range, the productivity is excellent, and properties such as the cohesion, chemical resistance, scratch resistance, and optical properties of the coating film can be further improved. It should be noted that in the present disclosure, "uncured" refers to an incompletely cured state, and in addition to the uncured state, it also includes a slightly cured state, that is, the concept of semi-cured.

[0094] The reaction rate of the (meth)acrylate contained in the uncured layer B is preferably 1% or more, 2% or more, 3% or more, 4% or more, or 5% or more, and is preferably 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less. If the reaction rate of the (meth)acrylate is within such a range, layer B becomes a semi-cured state, the stickiness is reduced, so the workability is improved, and the softness of layer B itself is improved, so it can also appropriately follow complex shapes during thermoforming. The reaction rate of the (meth)acrylate can be adjusted by, for example, the irradiation amount of ultraviolet rays.

[0095] The (meth)acrylate-based resin contained in layer B in the present disclosure can be either an oligomer or a prepolymer, and there is no particular limitation.

[0096] The glass transition temperature of the uncured product of the (meth)acrylate-based resin composition (composition B) is preferably 30 to 150 °C, more preferably 35 to 140 °C, and particularly preferably 40 to 130 °C. If it is in this range, defects such as adhesion during roll winding and cracks during thermoforming can be further reduced or suppressed.

[0097] The pencil hardness of the cured layer after irradiating the uncured product of the (meth)acrylate-based resin composition (composition B) with active energy rays such as ultraviolet rays to cure it is preferably H or more or 2H or more. As the upper limit of the pencil hardness, there is no particular limitation, and it can be 5H or less, 4H or less, or 3H or less. If the pencil hardness of the cured layer is in such a range, the wear resistance and scratch resistance can be further improved.

[0098] Here, the pencil hardness is a value obtained by the following measurement. That is, as described later in the examples, with an accumulated light amount of 2000 mJ / cm 2The value obtained by irradiating ultraviolet rays to a film obtained by coating and drying an uncured product (composition B) of a (meth)acrylate resin composition to cure the coating film to prepare a test piece and measuring the pencil hardness of the coating film of the test piece according to JIS K5600-5-4-1999.

[0099] In the present disclosure, the B layer may contain a photopolymerization initiator. By containing a photopolymerization initiator, the polymerization curing reaction of the hard coat based on light (ultraviolet ray) irradiation can be carried out in a short time. Examples of the photopolymerization initiator include benzophenone, benzoin, Michler's ketone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-diethoxyacetophenone, benzoyl dimethyl 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-morpholinopropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methylpropan-1-one, bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyrrol-1-yl)titanium, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, 2,4,6-trimethylbenzoyl diphenylphosphine oxide. The photopolymerization initiator may be used alone or in combination of two or more.

[0100] The photopolymerization initiator contained in the solid content of the B 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 B layer. If it is in such a range, good photocurability can be exhibited, and in addition, adverse conditions such as coloring of the B layer and manufacturing costs can be reduced or suppressed. In addition, in order to improve the photocurability, various known dyes and sensitizers may be added, for example.

[0101] The thickness of the B layer is not particularly limited and may be appropriately set so as to exhibit desired properties (for example, desired abrasion resistance) corresponding to the use. For example, from the viewpoints of abrasion resistance and scratch resistance, the thickness of the B layer is preferably in the range of 1 to 50 μm, more preferably in the range of 2 to 30 μm, further preferably in the range of 2.5 to 20 μm, and particularly preferably in the range of 3 to 10 μm.

[0102] For the sheet for thermoforming of the present disclosure, when the elongation at break in the MD direction of the peelable layer (C layer) described later at 100°C is β1 (%), and the elongation at break in the MD direction of the laminate after peeling the C layer from the sheet for thermoforming at 100°C is α1 (%), β1 - α1 needs to be -0.5% to 5.0%. As long as this condition is satisfied, the elongation at break in the MD direction and / or TD direction of the B layer at 100°C is not particularly limited. As this elongation at break, for example, it can be 0% or more, greater than 0%, 0.1% or more, 0.3% or more, 0.5% or more, 0.7% or more, or 1.0% or more, and can be 10% or less, 8.0% or less, 6.0% or less, 5.0% or less, 3.0% or less, or 1.0% or less. It should be noted that when it is difficult to measure the elongation at break of the B layer alone due to its thin thickness, for example, by applying the B layer to the above-mentioned A layer, measuring the elongation at break in this state, and then subtracting the elongation at break of the A layer alone, the elongation at break of the B layer can be obtained.

[0103] In the B layer of the present disclosure, various components can be appropriately incorporated within the range that does not affect the effects of the present disclosure. As such optional components, for example, leveling agents, defoaming agents, antifouling agents (such as surfactants), surface modifiers, and fillers (such as organic fillers and inorganic fillers) can be cited. These components can be used alone or in combination of two or more.

[0104] 〈Layer (C layer) peelable from B layer〉

[0105] The sheet for thermoforming of the present disclosure includes a layer (C layer: peelable layer) that can be peeled from the B layer. The C layer protects the performance of the B layer during sheet operation, heat treatment, etc., and thus can also be referred to as a protective layer or a protective film. Since the B layer, especially the dried B layer, does not exhibit adhesiveness, the C layer can include an adhesive layer capable of peeling from the B layer and a support layer that supports the adhesive layer. The C layer can include these two layers. In order to distinguish these layers in the C layer, the support layer can also be referred to as the C1 layer, and the adhesive layer can be referred to as the C2 layer. The C layer can also be indirectly applied to the B layer via other layers, but from the viewpoints of the effect of suppressing the warping portion of the peelable layer, etc., the C layer is preferably directly applied to the B layer.

[0106] From the viewpoints of thermoformability, operability, the effect of suppressing the warping portion of the peelable layer, etc., the C layer, for example, the support layer (C1 layer) constituting the C layer, is preferably an unstretched thermoplastic resin layer or a biaxially stretched thermoplastic resin layer. This thermoplastic resin layer can also be in the form of a film or a sheet.

[0107] The thermoplastic resin constituting the thermoplastic resin layer is not particularly limited. For example, polyolefin resins such as polyethylene, polypropylene, and poly(4-methylpentene-1), or modified polyolefin resins obtained by modifying such resins with ethylenically unsaturated carboxylic acids, etc.; cycloolefins such as norbornene-based ring-opening metathesis polymers, addition polymers, and addition copolymers with other olefins; biodegradable polymers such as polylactic acid and polybutylene succinate; polyamide resins such as nylon 6, 11, 12, 66 (including semi-aromatic polyamides); polymethyl methacrylate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, ethylene-vinyl acetate copolymer, polyacetal, polyglycolic acid, polystyrene, styrene copolymerized with polymethyl methacrylate, polycarbonate resins, polypropylene glycol terephthalate, polyethylene terephthalate (PET), poly(ethylene isophthalate) (IAPET), polybutylene terephthalate (PBT), poly(ethylene 2,6-naphthalate) (PEN), etc.; polyether sulfone, polyether ketone, modified polyphenylene ether, polyphenylene sulfide, polyetherimide, polyimide, polyarylate, tetrafluoroethylene-hexafluoropropylene copolymer, polyvinylidene fluoride, and acrylonitrile-butadiene-styrene copolymer. The thermoplastic resin can be used alone or in combination of two or more.

[0108] Among them, from the viewpoints of thermoformability, workability, and the effect of suppressing the warping portion of the peelable layer, etc., as the thermoplastic resin, at least one selected from polycarbonate resins, polypropylene, and modified polyolefin resins is preferred. Here, as the polycarbonate resin, the polycarbonate resin used in the above A layer can be used in the same manner.

[0109] When the C layer includes an adhesive layer (C2 layer), the adhesive for forming an adhesive layer capable of peeling from the B layer is not particularly limited. For example, (meth)acrylic polymers, natural rubbers, synthetic rubbers, polyolefin polymers, polyester polymers, polyether polymers, polyurethane polymers, silicone polymers, or other polymers can be used. The adhesive can be used alone or in combination of two or more.

[0110] The peel strength of the C layer from the B layer (the dried B layer) can be appropriately adjusted, for example, by adding an adhesion adjuster to the adhesive layer (C2 layer) constituting the C layer. As this peel strength, from the viewpoints of workability (operability) when peeling the peelable layer (C layer) and the effect of suppressing the warping portion of the peelable layer, etc., a range of 10 mN / 25 mm or more, 15 mN / 25 mm or more, or 20 mN / 25 mm or more, and 1000 mN / 25 mm or less, 800 mN / 25 mm or less, 500 mN / 25 mm or less, 450 mN / 25 mm or less, or 400 mN / 25 mm or less is preferred. The peel strength can be determined by the method described in the examples below.

[0111] For the C layer used in the thermoforming sheet of the present disclosure, when the elongation at break in the MD direction of the C layer at 100 °C is β1 (%) and the elongation at break in the MD direction of the laminate after peeling the C layer from the thermoforming sheet at 100 °C is α1 (%), as long as β1 - α1 is -0.5% to 5.0%, the elongation at break (β1) of the C layer in the MD direction at 100 °C is not particularly limited. As this elongation at break (β1), for example, it can be 0% or more, greater than 0%, 0.1% or more, 0.3% or more, 0.5% or more, 0.7% or more, or 1.0% or more, and can be 10% or less, 8.0% or less, 6.0% or less, or 5.0% or less.

[0112] As the elongation at break (β2) of the C layer in the TD direction at 100 °C, for example, it can be 0% or more, greater than 0%, 0.1% or more, 0.3% or more, 0.5% or more, 0.7% or more, or 1.0% or more, and can be 10% or less, 8.0% or less, 6.0% or less, or 5.0% or less.

[0113] As the thickness of the C layer, there is no particular limitation, and it can be appropriately set to obtain desired properties (such as protective properties). For example, from the viewpoint of the protective properties for the B layer, etc., the thickness of the C layer is preferably in the range of 10 to 100 μm, more preferably in the range of 15 to 50 μm, and most preferably in the range of 15 to 30 μm.

[0114] The C layer of the present disclosure can be appropriately blended with various components within the range that does not affect the effects of the present disclosure. As such optional components, for example, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, adhesion modifiers, dyes, pigments, and reinforcing fillers (such as glass fibers) can be cited. These components can be used alone or in combination of two or more.

[0115] In some embodiments, in the C layer of the present disclosure, the protruding defects with a height of 5 μm or more and an area of 0.1 mm 2 or more on the surface on the B layer side of the C layer are preferably 10 / m 2 or less, 8 / m 2 or less, 5 / m 2 or less, 3 / m 2 or less, 2 / m 2 or less, or 1 / m 2 or less. As the lower limit value of such defects, there is no particular limitation, and for example, it can be 0 / m 2 or more or greater than 0 / m 2 . If the proportion of the protruding defects is within such a range, the surface appearance of the cured B layer can be further improved. The protruding defects can be obtained by the method described in the examples below.

[0116] In some embodiments, the C layer of the present disclosure is as Figure 1 shown. The surface roughness (Sa) of the surface (109) of the C layer that contacts the B layer is preferably 150 nm or less, 120 nm or less, 100 nm or less, 80 nm or less, or 50 nm or less. As the lower limit value of this surface roughness, there is no particular limitation, and for example, it can be 1 nm or more, 5 nm or more, 10 nm or more, or 15 nm or more. If the surface roughness is within such a range, the surface appearance of the cured B layer can be further improved. The surface roughness (Sa) can be obtained by the method described in the examples below.

[0117] 〈β1 - α1〉

[0118] For the thermoforming sheet of the present disclosure and the decorative sheet prepared using this sheet, when laminating functional layers, design layers, etc. using this sheet, it is usually supplied at a temperature of about 20°C to 100°C. Therefore, the thermal expansion of each layer in this sheet reaches its maximum at around 100°C. Thus, for the thermoforming sheet of the present disclosure and the decorative sheet prepared using this sheet, when the elongation rate in the MD direction (machine direction) of the peelable layer (C layer) at 100°C is set as β1 (%), and the elongation rate in the MD direction of the laminate after peeling the C layer from the thermoforming sheet at 100°C is set as α1 (%), β1 - α1 needs to be -0.5% to 5.0%. By β1 - α1 being within such a range, for example, in the case of laminating functional layers, design layers, etc. and performing heat treatment, the generation of warping of the peelable layer can be reduced or suppressed, and the operability and thermoformability of the thermoforming sheet or the decorative sheet can be improved. As the range of β1 - α1, it is more preferably greater than -0.5%, -0.4% or more, -0.3% or more, -0.2% or more, or -0.1% or more, and less than 5.0%, 4.5% or less, 4.0% or less, 3.5% or less, 3.0% or less, or 2.5% or less. It should be noted that in the present disclosure, for example, when laminating functional layers, design layers, etc., the applied temperature does not exclude temperatures exceeding 100°C.

[0119] 〈β2 - α2〉

[0120] In some embodiments, for the sheet for thermoforming of the present disclosure, when the elongation at break in the TD direction (width direction) of the peelable layer (layer C) at 100 °C is β2 (%), and the elongation at break in the TD direction of the laminate after peeling layer C from the sheet for thermoforming at 100 °C is α2 (%), β2 - α2 can be -1.0% to 5.0%. If β2 - α2 is within such a range, the generation of warping of the peelable layer during thermoforming can be further reduced or suppressed, and the operability and thermoformability of the sheet for thermoforming or the decorative sheet can be further improved. As the range of β2 - α2, it is more preferably greater than -1.0%, -0.8% or more, -0.5% or more, -0.4% or more, -0.3% or more, -0.2% or more, or -0.1% or more, and less than 5.0%, 4.5% or less, 4.0% or less, 3.5% or less, 3.0% or less, or 2.5% or less.

[0121] 〈β1 - β2〉

[0122] In some embodiments, in the sheet for thermoforming of the present disclosure, regarding β1 and β2 described above, β1 - β2 can be -2.0% to 4.0%. If β1 - β2 is within such a range, the warping of the peelable layer (layer C) can be further reduced or suppressed. As the range of β1 - β2, it is more preferably -1.8% or more, -1.5% or more, -1.3% or more, -1.0% or more, -0.8% or more, -0.5% or more, -0.4% or more, -0.3% or more, -0.2% or more, or -0.1% or more, and less than 4.0%, 3.5% or less, 3.0% or less, 2.5% or less, 2.0% or less, 1.5% or less, or 1.0% or less.

[0123] 〈Any layer〉

[0124] The sheet for thermoforming of the present disclosure can further include one or more arbitrary layers within the range that does not affect the effects of the present disclosure according to the intended use and the like. As the arbitrary layer, it is not limited to the following layers. For example, the following layers can be used.

[0125] (Layer (D layer) containing (meth)acrylic resin)

[0126] In some embodiments, the sheet for thermoforming of the present disclosure can include a layer (layer D) containing (meth)acrylic resin. Layer D is preferably disposed between the above-mentioned layer A and layer B. If layer D is applied, appearance defects accompanied by thickness unevenness are less likely to occur, and the hardness and scratch resistance of the sheet for thermoforming can be further improved. Layer D can be a single layer, or can also be a laminate structure of two or more layers. In the case where layer D has a structure of two or more layers, in order to distinguish each layer in layer D, it can be referred to as layer D1, layer D2, etc.

[0127] The (meth)acrylic resin used in the D layer is preferably a resin mainly composed of a polymer of a methacrylate or acrylate. As the (meth)acrylic resin, a copolymer containing 50 mol% or more, more preferably 70 mol% or more, further preferably 80 mol% or more, and particularly preferably 90 mol% or more of methyl methacrylate is preferred.

[0128] As other copolymerization components, for example, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate can be cited. As other copolymerization components, in addition, for example, other ethylenically unsaturated monomers can be cited. As ethylenically unsaturated monomers, specifically, for example, vinyl aromatic compounds such as styrene, α-methylstyrene, and vinyltoluene, diene compounds such as 1,3-butadiene and isoprene, vinyl cyanides such as acrylonitrile and methacrylonitrile, acrylic acid, methacrylic acid, maleic anhydride, N-substituted maleimides, etc. can be cited. The copolymerization components can be used alone or in combination of two or more. The content of the copolymerization components is preferably 0 to 50% by mass, more preferably 0 to 30% by mass, and further preferably 0 to 20% by mass.

[0129] As a method for producing the (meth)acrylic resin, there is no particular limitation, and for example, an emulsion polymerization method, a suspension polymerization method, or a continuous polymerization method can be adopted.

[0130] The D layer of the present disclosure can be appropriately blended with various components within a range that does not affect the effects of the present disclosure. As such optional components, for example, heat stabilizers, colorants, mold release agents, lubricants, antistatic agents, and matting agents can be cited. These components can be used alone or in combination of two or more.

[0131] In order to improve toughness and the like, rubber particles can also be blended in the D layer. However, from the viewpoints of ensuring transparency and surface hardness, it is preferably substantially free of rubber particles. When rubber particles are blended, the blending amount can be, for example, 1% by mass or less, 0.5% by mass or less, or 0.1% by mass or less in the total solid content of the D layer.

[0132] As the thickness of the D layer, there is no particular limitation, and it can be appropriately set according to the use purpose of the thermoformed sheet and the like. For example, from the viewpoints of thermoformability and the like, the thickness of the D layer is preferably in the range of 5 to 300 μm, more preferably in the range of 8 to 250 μm, further preferably in the range of 10 to 200 μm, particularly preferably in the range of 20 to 150 μm, and most preferably in the range of 30 to 100 μm.

[0133] (Design layer)

[0134] In some embodiments, the sheet for thermoforming of the present disclosure may include a design layer. The design layer can be applied to any position of the sheet for thermoforming, but is preferably applied to the surface (107) on the side opposite to the B layer (103) of the A layer (101) of the sheet for thermoforming (100) as shown in Figure 1 FIG. The sheet obtained by thermoforming is typically cured in a state after peeling off the C layer, and the B layer is used as the upper surface. Therefore, if the design layer is applied to the surface on the side of the A layer opposite to the B layer, the design layer can be protected by at least the B layer and the A layer. The design layer can be formed over the entire surface of the applied surface, or can be formed partially. It should be noted that the sheet for thermoforming having a design layer may also be referred to as a decorative sheet.

[0135] The design layer is not particularly limited as long as it can exhibit designability (decorativeness). As the design layer, for example, a colored layer presenting a special color tone or a metallic color, and a pattern layer capable of imparting patterns (such as wood grain, stone grain), logos, patterns, etc. can be cited. The design layer can be one kind, or can be a layer formed by combining a plurality of design layers.

[0136] The thickness of the design layer can be various. For example, it can be 1 μm or more, 2 μm or more, or 5 μm or more, and further, it can be 50 μm or less, 30 μm or less, 10 μm or less, 8 μm or less, or 5 μm or less.

[0137] (Other layers)

[0138] As optional layers, in addition to this, any functional layer capable of imparting functions such as an antistatic layer, a conductive layer, a primer layer, and an adhesive layer can be adopted.

[0139] 〈Thickness of the sheet for thermoforming or decorative sheet〉

[0140] The thickness of the sheet for thermoforming or decorative sheet of the present disclosure is not particularly limited and can be appropriately set according to the usage purpose of each sheet, etc. For example, from the viewpoints of workability, thermoformability, decorative formability, etc., their thickness is preferably 0.05 mm to 3 mm, more preferably 0.1 mm to 2.5 mm, still more preferably 0.15 mm to 2 mm, and particularly preferably 0.2 mm to 1 mm.

[0141] 《Manufacturing method of the sheet for thermoforming》

[0142] The manufacturing method of the sheet for thermoforming of the present disclosure is not particularly limited. An example of the manufacturing method is shown below. It should be noted that in various manufacturing methods of the present disclosure, the above materials can be used in the same manner.

[0143] The single-layer sheet that constitutes the A layer of the thermoforming sheet of the present disclosure can be manufactured, for example, by a known extrusion method using the molding material A for the A layer. In addition, a laminated sheet having an A layer and an arbitrary D layer can be manufactured, for example, by a known coextrusion method using the molding material A for the A layer and the molding material D for the D layer. Here, the coextrusion method is generally a method of obtaining a multi-layer sheet by melting and extruding the molding material A and the molding material D using their respective extruders and laminating them using a feedblock or a manifold die head. By adjusting the extrusion amount of each extruder, the film forming speed, the die head sliding interval, etc., the total thickness and the thickness composition of the obtained laminated sheet can be controlled.

[0144] The sheet is formed by bringing the molten resin into close contact with a roll or a belt. Further, since the molten resin before cooling and solidification can be extruded by a metal roll to transfer a metal mirror surface, the surface appearance of the sheet can be made good. As the metal elastic roll, for example, a metal elastic roll having a shaft roll and a cylindrical metal film disposed so as to cover the outer peripheral surface of the shaft roll and contacting the molten resin, and a temperature-controlled fluid such as water or oil sealed between these shaft roll and the metal film; or a metal elastic roll formed by winding a metal band around the surface of a rubber roll. Among them, a metal elastic roll formed by winding a metal band around two or more rolls extrudes the molten resin with a wider surface on an arc, so that cooling can be performed in a state where stress is not left in the resin as much as possible.

[0145] As a method of laminating the B layer that constitutes the thermoforming sheet of the present disclosure on the above single-layer sheet or laminated sheet, a coating method is generally used. The coating method is not particularly limited, and examples thereof include a gravure coating method, a microgravure coating method, a jet rod coating method, a slide die coating method, and a slot die coating method. These are coating methods in which the coating film thickness is easily adjusted.

[0146] In the coating step, a (meth)acrylate-based active energy ray curable resin composition (Composition B), a hindered amine compound, a photopolymerization initiator, and other optional components as needed can be dissolved or dispersed in an appropriate solvent to prepare a coating material, and the coating material is coated on the above single-layer sheet or laminated sheet and dried to form a B layer.

[0147] The solvent is not particularly limited and can be appropriately selected according to the solubility of Composition B, as long as it is a solvent that can at least uniformly dissolve or disperse the solid components (resin, photopolymerization initiator, other optional components). Examples of such solvents include ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ethers (di Alkanes (such as tetrahydrofuran), aliphatic hydrocarbons (such as hexane), alicyclic hydrocarbons (such as cyclohexane), aromatic hydrocarbons (such as toluene and xylene), halogenated hydrocarbons (such as dichloromethane and dichloroethane), esters (such as methyl acetate, ethyl acetate, and butyl acetate), alcohols (such as methanol, ethanol, isopropanol, butanol, and cyclohexanol), cellosolves (such as methyl cellosolve and ethyl cellosolve), cellosolve acetates, sulfoxides, and amides. The solvents can be used alone or in combination of two or more.

[0148] As a method for laminating the peelable layer (layer C) of the present disclosure, for example, lamination processing is preferably used. The lamination processing can be carried out at room temperature or while heating. In the case of lamination processing carried out at room temperature, layer C preferably has a peelable adhesive layer. In the hot lamination processing carried out while heating, by making the lamination temperature higher than the glass transition temperature of layer B, layer B softens and fuses, so that the desired interfacial adhesion strength can be obtained with layer C.

[0149] Method for manufacturing a decorative sheet

[0150] For the thermoformable sheet of the present disclosure, as described above, a design layer can be further applied to the sheet to be used as a decorative sheet. The method for forming the design layer is not particularly limited. For example, forming a pattern layer by printing, forming a thin film layer of a metal or metal oxide, or a combination of these can be used. It should be noted that when applying a design layer, a functional layer, etc. to the thermoformable sheet, although not limited to the following temperatures, the sheet is typically supplied at a temperature of about 20°C to 100°C or about 60°C to 100°C.

[0151] As the printing method for forming a pattern layer, etc., there is no particular limitation. For example, known printing methods such as gravure printing, lithographic printing, flexographic printing, dry offset printing, pad printing, and screen printing can be used according to the product shape and printing purpose. As the material of the design layer when forming the design layer by such a printing method, for example, a coating obtained by dispersing pigments such as inorganic pigments, organic pigments, and gloss materials in a binder resin can be used.

[0152] As the method for forming a thin film layer of a metal or metal oxide, there is no particular limitation. For example, vapor deposition, spraying method, plating method, etc. can be cited. As the vapor deposition method, for example, vacuum vapor deposition method, sputtering, ion plating method, thermal CVD method, plasma CVD method, photo CVD method, etc. can be cited. As the spraying method, for example, atmospheric pressure plasma spraying method, reduced pressure plasma spraying method, etc. can be cited. As the plating method, for example, electroless plating method, molten plating method, electroplating method, etc. can be cited.

[0153] Method for manufacturing a molded body

[0154] The sheet for thermoforming or decorative sheet of the present disclosure can be used to manufacture a molded body by various conventionally known forming methods.

[0155] The molded body is not particularly limited, and examples thereof include interior and exterior decorative materials for automobiles, display screens for automobiles, electrical appliances, cosmetic cases, interior and exterior decorations for building materials, housings for various devices or products, housings for sundries, switches, buttons, keyboards, handles, control levers, buttons, and outer casings or exterior decorative parts of home appliances and AV equipment (such as personal computers), mobile phones, and mobile devices.

[0156] As a forming method for the molded body, for example, an insert molding method, which is an in-mold decoration method in injection molding, can be cited. In this method, a thermoforming sheet or decorative sheet pre-shaped according to the shape of the injection molding die cavity by vacuum forming or pressure forming is placed in the mold, molten resin is injected therein, and the thermoforming sheet or decorative sheet is welded to the resin molded product during injection molding to integrate them to obtain the molded body. It should be noted that in the forming method of the molded body of the present disclosure, from the viewpoint of the appearance quality of the final molded body, etc., the C layer that functions as a protective layer in the thermoforming sheet or decorative sheet is preferably peeled off from the sheet after drying the B layer and before thermoforming.

[0157] As another forming method, for example, a forming method can be cited in which a thermoforming sheet or decorative sheet is attached to the side of the mold cavity under vacuum pressure, molten resin is injected therein, and heat and pressure are applied to bond the thermoforming sheet or decorative sheet to the resin molded product to obtain the molded body.

[0158] As another forming method, a method of laminating using vacuum forming or pressure forming can be further cited. As a heating method for the thermoforming sheet or decorative sheet during thermoforming, various methods such as an infrared heater, an electric heater, high-frequency induction, a halogen lamp, microwave, high-temperature derivatives (such as steam), and a laser can be used.

[0159] The above-mentioned molding method is not limited to the following temperatures, but generally, according to the process, it is supplied at a temperature of about 140°C to 160°C. Therefore, the molded body produced is cooled or allowed to cool as needed. Next, the B layer applied to the molded body is cured by irradiating active energy rays (ultraviolet rays, visible light, infrared rays, or electron beams). The active energy rays can be polarized light or non-polarized light. Among the active energy rays, ultraviolet rays are preferred from the viewpoints of equipment cost, safety, operating cost, etc. In the case of curing by ultraviolet irradiation, a photoinitiator is typically used. As an energy ray source for ultraviolet rays, for example, a high-pressure mercury lamp, halogen lamp, xenon lamp, metal halide lamp, nitrogen laser, electron beam accelerator, and radioactive element can be used. The irradiation amount of ultraviolet rays is preferably in the range of 100 to 5000 mJ / cm 2 in terms of the cumulative exposure amount at a wavelength of 365 nm of ultraviolet rays, and more preferably in the range of 300 to 3000 mJ / cm 2 . If the irradiation amount is within such a range, a B layer with more excellent properties such as transparency and surface hardness can be obtained.

[0160] The oxygen concentration during the irradiation of active energy rays is preferably 5% or less, more preferably 3% or less, and particularly preferably 2% or less. Such an atmosphere with a low oxygen concentration or an oxygen-free atmosphere can be obtained, for example, by replacing the atmosphere of at least the irradiation part in the irradiation device with an inert gas. As the inert gas, for example, nitrogen, helium, neon, and argon can be cited.

[0161] Examples

[0162] Hereinafter, the present invention will be described more specifically using examples, but the present invention is not limited to these examples. The physical property measurements in the examples and comparative examples were carried out by the following methods.

[0163] 《Examples 1 to 15 and Comparative Examples 1 to 10》

[0164] 〈Measurement methods for various physical properties〉

[0165] (Glass transition temperature)

[0166] Using a 2920-type DSC manufactured by TA Instruments, the measurement was carried out at a heating rate of 20°C / minute, and the glass transition temperature was determined based on the inflection point.

[0167] (Thickness)

[0168] The thickness is the value at the center of the sheet width direction measured using an electron microfilm thickness gauge manufactured by ANRITSU. Here, the sheet width direction refers to the direction perpendicular to the sheet flow direction (MD direction) during film formation.

[0169] (Elongation rate in the MD direction at 100°C)

[0170] Cut out 5 sample films with a size of 10 mm in the MD direction (machine direction) and 5 mm in the TD direction (width direction) along the width direction of the test piece. Apply a tension of 40 mN to them in the MD direction using a Vacuum Riko TM-3000. Heat them at a rate of 10 °C per minute in a nitrogen atmosphere and measure the expansion and contraction characteristics in the MD direction. Divide the elongation at 100 °C by the sample length to obtain the elongation rate in the MD direction at 100 °C (unit: %). The elongation rate in the table is the average value of the elongation rates of the 5 samples. It should be noted that as the test piece, a peelable layer (layer C) and an unstretched laminate without layer C before applying layer C (a laminate composed of layer A and layer B, or a laminate composed of layer A, layer B, and layer D) are used. In the table, the elongation rate in the MD direction of the peelable layer (layer C) is denoted as β1, and the elongation rate in the MD direction of the laminate is denoted as α1.

[0171] (Elongation rate in the TD direction at 100 °C)

[0172] Cut out 5 sample films with a size of 10 mm in the TD direction and 5 mm in the MD direction along the width direction of the test piece. Apply a tension of 40 mN to them in the TD direction using a Vacuum Riko TM-3000. Heat them at a rate of 10 °C per minute in a nitrogen atmosphere and measure the expansion and contraction characteristics in the TD direction. Divide the elongation at 100 °C by the sample length to obtain the elongation rate in the TD direction at 100 °C (unit: %). The elongation rate in the table is the average value of the elongation rates of the 5 samples. It should be noted that as the test piece, a peelable layer (layer C) and an unstretched laminate without layer C before applying layer C (a laminate composed of layer A and layer B, or a laminate composed of layer A, layer B, and layer D) are used. In the table, the elongation rate in the TD direction of the peelable layer (layer C) is denoted as β2, and the elongation rate in the TD direction of the laminate is denoted as α2.

[0173] (Peeling force)

[0174] Cut out a thermoforming sheet with a size of 25 mm × 200 mm. Stick the A-layer side of the cut thermoforming sheet on a SUS plate with a width of 50 mm and a length of 250 mm. Fix this SUS plate to a tensile testing machine (manufactured by Toyo Baldwin Co., Ltd., trade name “TENSILON (trademark)”) and peel layer C at an angle of 180° and a peeling speed of 300 mm / minute, and measure the load. Conduct this measurement 5 times and use the average value as the peeling force (unit: mN / 25 mm).

[0175] (Surface roughness (Sa: arithmetic mean height))

[0176] The surface roughness (Sa: arithmetic mean height) was measured using a KEYENCE VK-9710 laser microscope. This measurement was performed 5 times, and the average value was taken as the surface roughness (unit: nm).

[0177] (Protrusion-like defect)

[0178] Aluminum was vacuum-evaporated on the surface side of the B layer for application to the C layer. It was observed using a KEYENCE VK-9710 laser microscope, and the number of protrusion-like defects with a height of 5 μm or more and an area of 0.1 mm 2 or more was counted. The generation frequency of minute protrusions was expressed as the number per meter. This measurement was performed 5 times, and the average value was recorded in the table.

[0179] (Warpage of the C layer)

[0180] Using a hot air dryer, the uncured thermoforming sheet was heated at 100 °C for 60 minutes. The sheet was observed from the C layer side, and whether the C layer peeled off from the B layer to cause warpage of the C layer was visually observed and evaluated according to the following criteria:

[0181] A: No warpage of the C layer was found.

[0182] B: Slight warpage of the C layer was found.

[0183] C: Obvious warpage of the C layer was found.

[0184] (Formability)

[0185] After peeling off the C layer, which serves as a protective layer, from the thermoforming sheet, it was preheated at 150 °C for 1 minute using a biaxial stretching test device (manufactured by Toyo Seiki Co., Ltd.), and then stretched to a stretching ratio of 1.3 times at the same temperature. The appearance of the sheet at this time was evaluated according to the following criteria:

[0186] A: No cracks or cloudiness were confirmed.

[0187] B: Slight cracks or a little cloudiness were confirmed.

[0188] C: Cracks or cloudiness were confirmed.

[0189] (Workability during processing)

[0190] The workability of the sheet during thermoforming processing using the thermoforming sheet was evaluated according to the following criteria:

[0191] A: No stickiness was confirmed, the C layer did not naturally peel off during operation, and the C layer could be easily peeled off.

[0192] B: Slight stickiness was confirmed, or the end face of the C layer naturally peeled off during operation, or the C layer could not be easily peeled off.

[0193] C: Viscosity is confirmed, or the C layer peels off naturally during operation, or the C layer is difficult to peel off.

[0194] (Surface appearance of the molded product)

[0195] After peeling off the C layer as a protective layer from the thermoforming sheet, it was preheated for 1 minute at a temperature of 150 °C using a biaxial stretching test device (manufactured by Toyo Seiki Co., Ltd.), and then stretched to a stretching ratio of 1.3 times at the same temperature. Ultraviolet rays were irradiated from the B layer side with an accumulated light quantity of 2000 mJ / cm 2 to cure the B layer. The appearance of the surface of the sheet, that is, the surface of the cured B layer, was evaluated according to the following criteria:

[0196] A: No defects such as scratches, wrinkles, unevenness, etc. were found.

[0197] B: Slight defects such as scratches, wrinkles, unevenness, etc. were found.

[0198] C: Some defects such as scratches, wrinkles, unevenness, etc. were found.

[0199] D: Obvious defects such as scratches, wrinkles, unevenness, etc. were found.

[0200] (Haze)

[0201] The haze value was measured using a NDH-2000 (D65 light source) manufactured by Nippon Denshoku Industries Co., Ltd. This measurement was performed 5 times, and the average value was used as the haze value (unit: %).

[0202] (Pencil hardness)

[0203] The pencil hardness of the cured B layer of the sheet produced in the above (surface appearance of the molded product) evaluation was measured according to JIS K5600-5-4-1999.

[0204] 〈Preparation Example 1〉(Manufacture of polyester-based thermoplastic elastomer)

[0205] Using a dibutyltin diacetate catalyst, after transesterification of 100 parts by mass of dimethyl isophthalate, 13 parts by mass of dimethyl sebacate, and 80 parts by mass of hexamethylene diol, polycondensation was carried out under reduced pressure to obtain an amorphous polyester (soft segment) with an intrinsic viscosity of 1.06 and no endothermic peak caused by crystal melting when measured by the DSC method. Relative to 100 parts by mass of the above polyester, 32 parts by mass of polybutylene terephthalate particles (hard segment) with an intrinsic viscosity of 0.98 were added, and the reaction was further carried out at 240 °C for 45 minutes. Then, 0.03 parts by mass of phenylphosphonic acid was added to stop the reaction. The obtained polymer had a melting point of 190 °C and an intrinsic viscosity of 0.93.

[0206] 〈Example 1〉

[0207] (Molding material A)

[0208] Pre-dry the polycarbonate resin particles (Panlite L1250WP manufactured by Teijin, a homopolycarbonate resin of bisphenol A (PC-A, inherent viscosity molecular weight 23,900)) and the thermoplastic elastomer obtained in Preparation Example 1 above respectively. Mix them in a V-type mixer in such a way that the thermoplastic elastomer is 10 parts by mass with respect to 100 parts by mass of the polycarbonate resin particles. Then, extrude using a twin-screw extruder at a barrel temperature of 260°C to form particles, and obtain the molding material A for the A layer. The glass transition temperature of the molding material A is 120°C.

[0209] (Molding material D)

[0210] As the molding material D for the D layer, prepare an acrylic resin (Acrypet VH-001 manufactured by Mitsubishi Rayon, an acrylic resin copolymerized from 95 mol% of methyl methacrylate and 5 mol% of methyl acrylate).

[0211] (Co-extrusion)

[0212] Use a single-screw extruder with a screw diameter of 40 mm to extrude the molding material A and the molding material D from a 650-mm-wide T-die in a feedblock manner under the conditions of a barrel temperature of 260°C (for the molding material A), 250°C (for the molding material D), a screw rotation speed of 109 rpm (for the molding material A), and 11 rpm (for the molding material D). After extruding, press and cool the molten resin with a metal roll and a metal sleeve roll, then perform edge trimming and wind it at a winding speed of 10.3 m / min to produce a laminated sheet with a double-layer structure of A layer / D layer (A layer about 200 μm, D layer about 100 μm), a width of about 400 mm, and a thickness of about 0.3 mm.

[0213] (Coating preparation)

[0214] As the coating for forming the B layer, use methyl isobutyl ketone to make 100 parts by mass of the polyurethane acrylate-based ultraviolet curable resin "PHOLUCID (trademark) No. 371C (trade name)" (solid content 40%, manufactured by China Coatings), 5 parts by mass of IRGACURE (trademark) 184 (photoinitiator, manufactured by Ciba Specialty Chemicals), and 3 parts by mass of the hindered amine-based compound "TINUVIN (trademark) 292 (trade name)" (manufactured by BASF) so that the solid content concentration in the ultraviolet curable resin coating is 30%, and stir well to prepare the coating.

[0215] (Coating)

[0216] Using a rod coater (#8), the coating material for forming the B layer was applied to the D layer side of the laminated sheet of the A layer and the D layer, and hot air dried in a drying oven at 100 °C for 5 minutes to form a B layer with a coating film thickness of 5 μm. The reaction rate of the acrylate at this time was 5%. Further, a protective film (C layer) was disposed on the B layer and pressed with a pinch roll to produce a thermoforming sheet having a thickness of about 0.37 mm. The various evaluation results are shown in Tables 1 to 3. It should be noted that as the protective film (C layer) in each table, PCLR manufactured by Teijin, which is a film with a total thickness of about 70 μm having an acrylic adhesive layer applied on a polycarbonate support layer, was used. In addition, in the resin type and adhesive type of the protective film (C layer) in each table, PC is polycarbonate, PP is polypropylene, PO is polyolefin, PE is polyethylene, and PET is polyethylene terephthalate.

[0217] 〈Examples 2 to 11〉

[0218] In the (coating) process, the protective film (C layer) was changed as shown in Table 1, and except for this, a thermoforming sheet was produced in the same manner as in Example 1. The various evaluation results are shown in Table 1. It should be noted that FSA-010C described as the protective film (C layer) in each table is manufactured by Futamara Chemical, MX157N is manufactured by Nihon Matai, A-1, SPV-TP-4030, SPV-V420, B-2, and SPV-C6010 are manufactured by Nitto Denko, FM-325 is manufactured by Oji Paper, R415A and 7H52 are manufactured by Toray, UM1010 is manufactured by Tredegar, and JA13K and NSA22T are films manufactured by Sun A Kaken.

[0219] 〈Example 12〉

[0220] In (Forming Material A), the thermoplastic elastomer obtained in Preparation Example 1 was not blended, and except for this, a thermoforming sheet was produced in the same manner as in Example 1. The various evaluation results are shown in Table 2.

[0221] 〈Example 13〉

[0222] In the (coextrusion) process, Forming Material D was not used, that is, a single-layer sheet having a width of 400 mm and a single-layer structure (A layer: 300 μm) composed of the A layer was produced, and except for this, a thermoforming sheet was produced in the same manner as in Example 1. The various evaluation results are shown in Table 2.

[0223] 〈Example 14〉

[0224] In the (coating) process, hot air drying was performed in a drying oven at 80 °C for 1 minute to semi-cure the B layer so that the reaction rate of the acrylate was 1%, and except for this, a thermoforming sheet was produced in the same manner as in Example 1. The various evaluation results are shown in Table 2.

[0225] <Example 15>

[0226] In the (coating) process, ultraviolet rays were irradiated from the B layer side with an accumulated light quantity of 50 mJ / cm 2 to semi-cure the B layer in such a manner that the reaction rate of the acrylate was 30%. Except for this, a thermoforming sheet was produced in the same manner as in Example 1. The various evaluation results are shown in Table 2.

[0227] <Comparative Example 1>

[0228] In the (coating) process, a thermoforming sheet was produced in the same manner as in Example 1 without using the protective film (C layer). The various evaluation results are shown in Table 3.

[0229] <Comparative Examples 2 - 5>

[0230] In the (coating) process, ultraviolet rays were irradiated from the B layer side with an accumulated light quantity of 2000 mJ / cm 2 to cure the B layer in such a manner that the reaction rate of the acrylate was 70%. And in the (coating) process, the protective film (C layer) was changed to the film shown in Table 3. Except for this, a thermoforming sheet was produced in the same manner as in Example 1. The various evaluation results are shown in Table 3.

[0231] <Comparative Examples 6 - 9>

[0232] In the (coating) process, hot air drying was performed in a drying oven at 80°C for 5 minutes to semi-cure the B layer in such a manner that the reaction rate of the acrylate was 3%. And in the (coating) process, the protective film (C layer) was changed to the film shown in Table 3. Except for this, a thermoforming sheet was produced in the same manner as in Example 1. The various evaluation results are shown in Table 3.

[0233] [Table 1]

[0234]

[0235] [Table 2]

[0236]

[0237] [Table 3]

[0238]

[0239] Industrial Applicability

[0240] The sheet for thermoforming and the decorative sheet of the present disclosure can reduce or suppress the generation of warping of the peelable layer during thermoforming, and have excellent workability, thermoformability, etc. Therefore, the molded body using the sheet for thermoforming and the decorative sheet is useful as, for example, interior and exterior decoration materials for automobiles, indicator screens for automobiles, electrical appliances, cosmetic cases, interior and exterior decorations for building materials, casings for various devices or products, casings for sundries, switches, buttons, keyboards, handles, control levers, buttons, and outer casings or outer decoration parts of home appliances and AV equipment (such as personal computers), mobile phones, and mobile devices.

[0241] Symbol Explanation

[0242] 100 Sheet for thermoforming

[0243] 101 Layer containing a thermoplastic resin (layer A)

[0244] 103 Layer formed from the uncured product of a (meth)acrylate-based active energy ray curable resin composition (composition B) (layer B)

[0245] 105 Layer that can be peeled from layer B (layer C)

[0246] 107 Surface of layer A on the side opposite to layer B

[0247] 109 Surface of layer C on the layer B side

Claims

1. A sheet for thermoforming, which is formed by laminating at least three layers of layer A, layer B, and layer C in sequence. Layer A is a layer containing a thermoplastic resin. Layer B is a layer formed from an uncured product of a (meth)acrylate-based active energy ray curable resin composition, i.e., composition B. Layer C is a layer that can be peeled off from layer B. When the elongation rate in the MD direction of layer C at 100 °C is set as β1, and the elongation rate in the MD direction of the laminate after peeling layer C from the thermoforming sheet at 100 °C is set as α1, β1−α1 is from −0.5% to 5.0%.

2. The sheet for thermoforming according to claim 1, wherein, When the elongation rate in the TD direction of layer C at 100 °C is set as β2, β1−β2 is from −2.0% to 4.0%.

3. The sheet for thermoforming according to claim 1 or 2, wherein, Layer C contains an unstretched thermoplastic resin layer or a biaxially stretched thermoplastic resin layer.

4. The sheet for thermoforming according to claim 1 or 2, wherein, The peel force of layer C from layer B is from 10 mN / 25 mm to 1000 mN / 25 mm.

5. The sheet for thermoforming according to claim 1 or 2, wherein, Protrusion defects on the surface of the B layer side of the C layer, with a height of 5 μm or more and an area of 0.1 mm 2 or more, are 10 per m 2 or less.

6. The sheet for thermoforming according to claim 1 or 2, wherein, The surface roughness Sa of the surface on the layer B side of layer C is 150 nm or less.

7. The sheet for thermoforming according to claim 1 or 2, wherein, The reaction rate of the (meth)acrylate contained in layer B is from 2% to 50%.

8. The sheet for thermoforming according to claim 1 or 2, wherein, Layer C contains at least one resin selected from polycarbonate-based resins, polypropylene, and modified polyolefin-based resins.

9. The sheet for thermoforming according to claim 1 or 2, wherein, Layer A contains a polycarbonate-based resin.

10. The sheet for thermoforming according to claim 9, wherein, In layer A, 1 to 20 parts by mass of a polyester-based thermoplastic elastomer is contained relative to 100 parts by mass of the polycarbonate-based resin.

11. The sheet for thermoforming according to claim 1 or 2, wherein, A layer containing a (meth)acrylic resin, i.e., layer D, is provided between layer A and layer B.

12. A decorative sheet, which has a design layer on the surface of layer A of the thermoforming sheet according to claim 1 or 2 on the side opposite to layer B.

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