Laminate for thermoforming and molded article obtained by molding same

Abstract

The present invention is capable of providing a laminate for thermoforming comprising a substrate layer, a primer layer, an adhesive layer, and a backer material in this order. The primer layer has a thickness of 0.2-1.0 μm, the adhesive layer comprises a two-component curable composition containing a polyester-based adhesive and an isocyanate-based curing agent, and the content of the isocyanate-based curing agent is 2-20 parts by mass with respect to 100 parts by mass of the polyester-based adhesive contained in the adhesive layer.

Description

Thermoforming laminate and molded article obtained by molding the same

[0001] The present invention relates to a thermoforming laminate and a molded article obtained by molding the same, and in particular to a thermoforming laminate that can be suitably used for printing (e.g., gravure printing, screen printing, wet coating, etc.) and a molded article obtained by molding the same.

[0002] Acrylic resins are excellent in surface hardness, transparency, scratch resistance, and weather resistance. Meanwhile, polycarbonate resins are excellent in impact resistance. For this reason, laminates having an acrylic resin layer and a polycarbonate resin layer are excellent in surface hardness, transparency, scratch resistance, weather resistance, and impact resistance, and are used in display windows for automobile parts, home appliances, electronic devices, and portable information terminals (Patent Document 1). In recent years, with the diversification of design needs, there has been a demand for products with enhanced design, such as front panels of display devices, that are thermoformed by vacuum forming or pressure forming. Due to the excellent performance described above, laminates having an acrylic resin layer and a polycarbonate resin layer have been attempted to be used as front panels.

[0003] Polycarbonate is not an easy adherend, so methods of using various adhesives and surface treatments in combination have been proposed, but because polycarbonate resin itself does not have good solvent resistance, using a solvent that dissolves it well causes the polycarbonate surface to whiten, resulting in a loss of transparency and a poor appearance.In addition, because polycarbonate does not have good moisture permeability, when it is bonded to other materials using adhesives or surface treatments in combination and a moisture resistance test is performed, moisture penetrates the interface between the polycarbonate and the adhesive, resulting in a decrease in adhesive strength.

[0004] For example, solvents commonly used in commercially available adhesives are toluene, xylene, ethyl acetate, methyl ethyl ketone, etc. These solvents cause cracks and whitening in polycarbonate resins.

[0005] International Publication No. 2016 / 060100

[0006] Meanwhile, there is a growing need for thermoforming laminates in which a substrate layer containing a polycarbonate resin or the like is laminated with a backing material, and there is a demand for improved adhesive strength between the substrate layer and the backing material. Therefore, an object of the present invention is to provide a thermoforming laminate that can improve the initial adhesive strength between the substrate layer and the backing material, maintain the adhesive strength after wet heat treatment, and be suitably used for printing (e.g., gravure printing, screen printing, wet coating, etc.), and a molded article obtained by molding the same.

[0007] As a result of extensive research into solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by adjusting the film thickness of the primer layer and the content of the isocyanate-based curing agent in the adhesive layer.

[0008] <1> A thermoforming laminate comprising, in this order, a substrate layer, a primer layer, an adhesive layer, and a backing material, wherein the primer layer has a thickness of 0.2 to 1.0 μm, and the adhesive layer is made of a two-component curing composition containing a polyester adhesive and an isocyanate curing agent, and the content of the isocyanate curing agent is 2 to 20 parts by mass per 100 parts by mass of the polyester adhesive contained in the adhesive layer. <2> The thermoforming laminate according to <1> above, wherein the backing material contains a thermoplastic resin. <3> The thermoforming laminate according to <2> above, wherein the thermoplastic resin contains a polycarbonate resin. <4> The thermoforming laminate according to any one of <1> to <3> above, wherein the backing material contains a layer containing a polycarbonate resin and a layer containing an acrylic resin. <5> The thermoforming laminate according to <4> above, wherein the adhesive layer is disposed on the side of the layer containing the acrylic resin. <6> The thermoforming laminate according to any one of <1> to <5> above, wherein the base layer contains a polycarbonate resin. <7> The thermoforming laminate according to any one of <1> to <6> above, wherein the base layer contains a layer containing a polycarbonate resin and a layer containing an acrylic resin. <8> The thermoforming laminate according to <7> above, wherein the primer layer is disposed on the side of the layer containing a polycarbonate resin. <9> The thermoforming laminate according to any one of <1> to <8> above, wherein the primer layer contains an active energy ray-curable resin having a (meth)acryloyl group or a thermosetting resin having a (meth)acryloyl group. <10> The thermoforming laminate according to any one of <1> to <9> above, wherein the adhesive layer has a thickness of 2 to 25 μm. <11> The thermoforming laminate according to any one of the above <1> to <10>, wherein, after curing of the two-component curing composition, an adhesive strength [N / 25 mm] required to peel the base layer from the backing material at a peel speed of 30 mm / min and a peel angle of 90° is 4.0 [N / 25 mm] or more, and an adhesive strength [N / 25 mm] after a moist heat test performed under conditions of 85°C and 85% RH for 500 hours is 1.5 [N / 25 mm] or more.<12> The thermoforming laminate according to any one of <1> to <11> above, further comprising a printed layer between the primer layer and the adhesive layer. <13> A molded article obtained by molding the thermoforming laminate according to any one of <1> to <12> above.

[0009] According to the present invention, it is possible to provide a thermoforming laminate that can improve the initial adhesive strength between a base layer and a backing material, maintain the adhesive strength after wet heat treatment, and be suitably used for printing (e.g., gravure printing, screen printing, wet coating, etc.), and a molded article obtained by molding the same.

[0010] Hereinafter, the present invention will be described in detail by way of examples and working examples, but the present invention is not limited to the illustrated examples and working examples, and can be carried out by any method as long as it does not significantly deviate from the content of the present invention.

[0011] The thermoformable laminate of the present invention comprises a substrate layer, a primer layer, an adhesive layer, and a backer material in this order.

[0012] <Substrate Layer> The substrate layer preferably contains a thermoplastic resin. The type of thermoplastic resin is not particularly limited, but various resins such as polycarbonate (PC) resin, acrylic resin such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), triacetyl cellulose (TAC), polyethylene naphthalate (PEN), polyimide (PI), cycloolefin copolymer (COC), norbornene-containing resin, polyethersulfone, cellophane, and aromatic polyamide are used. Of the above-mentioned thermoplastic resins, the substrate layer preferably contains at least a polycarbonate resin, and more preferably contains an aromatic polycarbonate resin from the viewpoints of toughness and heat resistance.

[0013] The polycarbonate resin is not particularly limited as long as it contains a carbonate bond, i.e., an -[O-R-OCO]- unit (where R may contain an aliphatic group, an aromatic group, or both an aliphatic group and an aromatic group, and may have a straight-chain structure or a branched structure), in the molecular main chain. However, aromatic polycarbonate resins are preferred, and it is particularly preferred to use polycarbonate resins containing structural units of the following formula (4a). By using such polycarbonate resins, a thermoforming laminate with excellent impact resistance can be obtained.

[0014] Specifically, aromatic polycarbonate resins (for example, Iupilon S-2000, Iupilon S-1000, Iupilon E-2000; manufactured by Mitsubishi Engineering Plastics Corporation) can be used as the polycarbonate resin.

[0015] In recent years, polycarbonate resins to which a monohydric phenol represented by the following general formula (4) has been added as a terminal terminator have been used for the purpose of controlling the glass transition temperature of the polycarbonate resin. In the above embodiment, a polycarbonate resin to which such a terminal terminator has been added can also be used. (In the formula, R １ represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 36 carbon atoms; R ２ ~R ５ each independently represents a hydrogen atom, a halogen, or an optionally substituted alkyl group having 1 to 20 carbon atoms or an optionally substituted aryl group having 6 to 12 carbon atoms; here, the substituent is a halogen, an optionally substituted alkyl group having 1 to 20 carbon atoms, or an optionally substituted aryl group having 6 to 12 carbon atoms.) In this specification, "alkyl groups" and "alkenyl groups" may be linear or branched and may have a substituent.

[0016] More preferably, the monohydric phenol represented by the general formula (4) is represented by the following general formula (5). (In the formula, R １ represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 36 carbon atoms.

[0017] R in general formula (4) or general formula (5) １ It is more preferable that the number of carbon atoms in R is within a specific numerical range. １ The upper limit of the number of carbon atoms in R is preferably 36, more preferably 22, and particularly preferably 18. １ The lower limit of the number of carbon atoms is preferably 8, and more preferably 12.

[0018] Among the monohydric phenols represented by general formula (4) or general formula (5), it is particularly preferable to use either or both of parahydroxybenzoic acid hexadecyl ester and parahydroxybenzoic acid 2-hexyldecyl ester as the end terminator.

[0019] For example, in general formula (5), R １ When a monohydric phenol in which the alkyl group has 16 carbon atoms is used as the end terminator, a polycarbonate resin excellent in glass transition temperature, melt fluidity, moldability, drawdown resistance, etc. can be obtained, and the monohydric phenol also has excellent solubility in solvents during the production of the polycarbonate resin, and this is particularly preferred.

[0020] On the other hand, R in general formula (4) or general formula (5) １ If the number of carbon atoms in R is too large, the solubility of the monohydric phenol (terminal terminator) in organic solvents tends to decrease, which may result in a decrease in productivity during the production of polycarbonate resins. １ When the number of carbon atoms in R is 36 or less, the productivity in producing the polycarbonate resin is high and the economic efficiency is also good. １ When the carbon number of R in the general formula (4) or (5) is 22 or less, the monohydric phenol has particularly excellent solubility in organic solvents, and the productivity in producing the polycarbonate resin can be significantly increased, resulting in improved economic efficiency. An example of a polycarbonate resin using such a monohydric phenol is Iupizeta T-1380 (manufactured by Mitsubishi Gas Chemical Company). １ If the number of carbon atoms is too small, the glass transition temperature of the polycarbonate resin will not be sufficiently low, and thermoformability may decrease.

[0021] The weight-average molecular weight of a polycarbonate resin can affect the impact resistance and molding conditions of a thermoforming laminate. In other words, if the weight-average molecular weight is too low, the impact resistance of the thermoforming laminate may decrease. If the weight-average molecular weight is too high, an excessive heat source may be required when forming a substrate layer containing a polycarbonate resin. Furthermore, depending on the molding method selected, high temperatures may be required, which may expose the polycarbonate resin to high temperatures and adversely affect its thermal stability. The weight-average molecular weight of the polycarbonate resin is preferably 15,000 to 75,000, more preferably 20,000 to 70,000, and even more preferably 20,000 to 65,000. The weight-average molecular weight in this specification is the weight-average molecular weight measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0022] The glass transition point (Tg) of the polycarbonate resin is preferably 90 to 190° C., more preferably 100 to 170° C., and particularly preferably 110 to 150° C. In this specification, the glass transition point is a temperature measured using a differential scanning calorimeter with a 10 mg sample at a heating rate of 10° C. / min and calculated by the midpoint method.

[0023] The substrate layer may contain other resins in addition to the polycarbonate resin. Examples of such resins include polyester resins. The polyester resin preferably contains terephthalic acid as the dicarboxylic acid component, but may also contain a dicarboxylic acid component other than terephthalic acid. For example, a polyester resin (so-called "PETG") obtained by polycondensation of a glycol component containing 80 to 60 mol% of ethylene glycol as the main component and 20 to 40 mol% of 1,4-cyclohexanedimethanol (total 100 mol%) is preferred. When the resin in the substrate layer contains other resins, the amount of such other resins is preferably 0 to 50% by mass, more preferably 0 to 30% by mass, and particularly preferably 0 to 20% by mass, relative to the total mass of the substrate layer.

[0024] The substrate layer may further contain additives. Additives commonly used in thermoforming laminates can be used, including, for example, antioxidants, anti-coloring agents, anti-static agents, release agents, lubricants, dyes, pigments, plasticizers, flame retardants, resin modifiers, compatibilizers, and reinforcing materials such as organic and inorganic fillers. The method for mixing the additives and resin is not particularly limited, and methods such as compounding the entire amount, dry blending a masterbatch, and dry blending the entire amount can be used. The amount of additive is preferably 0 to 10% by mass, more preferably 0 to 7% by mass, and particularly preferably 0 to 5% by mass, relative to the total mass of the substrate layer.

[0025] Acrylic resins are also preferred as thermoplastic resins contained in the substrate layer. Specific examples include, but are not limited to, homopolymers of various (meth)acrylic acid esters, such as polymethyl methacrylate (PMMA) and methyl methacrylate (MMA), or copolymers of PMMA, MMA, or their constituent monomers with one or more other monomers. A mixture of multiple resins can also be used. Among these, (meth)acrylates containing a cyclic alkyl structure, which have low birefringence, low moisture absorption, and excellent heat resistance, are preferred. Examples of such (meth)acrylates include, but are not limited to, ACRYPET (manufactured by Mitsubishi Rayon Co., Ltd.), DELPET (manufactured by Asahi Kasei Chemicals Corporation), and PARAPET (manufactured by Kuraray Co., Ltd.).

[0026] The substrate layer may also be formed of multiple layers having different compositions. In the present invention, from the viewpoint of formability, it is preferable to use a substrate layer consisting of a layer containing the above-mentioned polycarbonate resin and a layer containing an acrylic resin. The substrate layer consisting of multiple layers is not limited to a two-layer structure, and may be three or more layers. For example, when using a substrate layer containing a layer containing a polycarbonate resin and a layer containing an acrylic resin, it is preferable that a primer layer is laminated on the side of the layer containing the polycarbonate resin. By using a substrate layer with a multilayer structure containing a layer containing a polycarbonate resin and a layer containing an acrylic resin, it is possible to maintain the thermoformability of the substrate layer while improving the surface hardness of the substrate layer.

[0027] The viscosity average molecular weight of the thermoplastic resin contained in the substrate layer is preferably 15,000 to 40,000, more preferably 20,000 to 35,000, and even more preferably 22,500 to 25,000.

[0028] The content of the thermoplastic resin in the substrate layer is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more, relative to the mass of the substrate layer. Furthermore, in a layer containing polycarbonate resin as the main component, the proportion of polycarbonate resin in the layer is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more. In a layer containing acrylic resin as the main component, the proportion of acrylic resin in the layer is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more. By setting the content of the thermoplastic resin within the above range, the flowability during injection molding tends to be further improved.

[0029] In a preferred embodiment of the present invention, the thickness of the acrylic resin-containing layer affects the surface hardness and impact resistance of the thermoforming laminate. That is, if the thickness of the acrylic resin-containing layer is too thin, the surface hardness tends to decrease. If the thickness of the acrylic resin-containing layer is too large, the impact resistance tends to decrease. The lower limit of the thickness of the acrylic resin-containing layer is preferably 5 μm, more preferably 7 μm, and even more preferably 8 μm. The upper limit of the thickness of the acrylic resin-containing layer is preferably 200 μm, more preferably 180 μm, and even more preferably 150 μm.

[0030] In a preferred embodiment of the present invention, the total thickness of the polycarbonate resin-containing layer and the acrylic resin-containing layer affects impact resistance. If the total thickness of the polycarbonate resin-containing layer and the acrylic resin-containing layer is too thin, impact resistance tends to decrease. The total thickness of the polycarbonate resin-containing layer and the acrylic resin-containing layer is preferably 50 to 3,000 μm, more preferably 60 to 2,000 μm, and even more preferably 70 to 1,000 μm.

[0031] In a preferred embodiment of the present invention, an ultraviolet absorber can be mixed into the polycarbonate resin-containing layer and / or the acrylic resin-containing layer. If the content of the ultraviolet absorber is too low, light resistance will be insufficient. If the content is too high, depending on the molding method, excess ultraviolet absorber may scatter due to high temperatures and contaminate the molding environment, causing problems. Examples of ultraviolet absorbers include benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, benzoate-based ultraviolet absorbers, hindered amine-based ultraviolet absorbers, and triazine-based ultraviolet absorbers. The mixing method is not particularly limited, and methods such as compounding the entire amount, dry-blending a masterbatch, and dry-blending the entire amount can be used.

[0032] The surface of the base layer in the present invention may have an uneven shape. The uneven surface shape scatters external light, preventing a decrease in visibility due to reflection of external light or image glare. In addition, when placed on the surface of a liquid crystal display device, good contrast is achieved, and the occurrence of so-called "glare" can be suppressed, in which interference between the pixels of the liquid crystal display device and the uneven surface shape of the antiglare film results in a brightness distribution that makes it difficult to see. In addition, the diffuse reflection of light due to the fine unevenness on the layer surface suppresses surface gloss, achieving a satin-like matte appearance.

[0033] Methods for imparting an uneven shape to the surface of the base layer include, for example, adding fine particles to the base layer, applying a coating material containing fine particles to the surface of the base layer, forming unevenness on the surface by passing the base layer or the manufactured base layer through a heated roll that has been given an uneven surface, or forming unevenness by an unevenness-making method such as sandblasting, shot blasting, liquid honing, or solvent treatment.

[0034] The fine particles are not particularly limited, but examples thereof include acrylic fine particles, styrene fine particles, acrylonitrile fine particles, urethane fine particles, nylon fine particles, polyimide fine particles, melamine fine particles, silicon fine particles, silica fine particles, and zirconia fine particles. Among these, crosslinked acrylic fine particles are preferred. The crosslinked acrylic fine particles are not particularly limited. Examples of crosslinked acrylic fine particles include crosslinked polymethyl methacrylate fine particles, crosslinked polyethyl methacrylate fine particles, and crosslinked poly(normal butyl methacrylate) fine particles.

[0035] Examples of methods for applying the coating material containing the above-mentioned fine particles include microgravure coating, wire bar coating, direct gravure coating, die coating, dipping, spray coating, reverse roll coating, curtain coating, comma coating, knife coating, and spin coating.

[0036] <Primer Layer> The primer layer is provided between the substrate layer and the adhesive layer. An additional layer may be present between the primer layer and the substrate layer in the present invention. One of the features of the present invention is that the primer layer has a thickness of 0.2 to 1.0 μm, preferably 0.3 to 0.8 μm, and more preferably 0.5 to 0.8 μm. If the thickness is less than 0.2 μm, the solvent contained in the adhesive layer or printed layer may cause cracking or whitening of the substrate layer, while if the thickness exceeds 1.0 μm, the adhesive strength decreases. The thickness of the primer layer can be measured by observing the cross section with a microscope or the like and measuring from the coating interface to the surface.

[0037] In a preferred embodiment of the present invention, the primer layer is formed by polymerizing and curing a primer composition containing an active energy ray-curable resin having a (meth)acryloyl group or a thermosetting resin having a (meth)acryloyl group. Hereinafter, a polymer having a (meth)acryloyl group will also be referred to as a (meth)acryloyl polymer. The primer layer may contain one or more types of (meth)acryloyl polymers. The primer composition used in the present invention is preferably energy ray-curable.

[0038] The (meth)acryloyl polymer preferably used in the present invention is an acrylic polymer having a radically polymerizable (meth)acryloyl group in the side chain, and is a polymer that can be cured by UV, EB, or heat. The (meth)acryloyl polymer preferably used in the present invention can also be a polymer obtained by polymerizing a (meth)acrylic monomer, oligomer, or prepolymer that contains a (meth)acryloyl group as a polymerizable group.

[0039] Any (meth)acrylic monomer can be used as long as it has a (meth)acryloyl group as a functional group in the molecule, and it may be a monofunctional monomer, a difunctional monomer, or a trifunctional or higher functional monomer. Examples of monofunctional monomers include (meth)acrylic acid and (meth)acrylic acid esters. Specific examples of bifunctional and / or trifunctional or higher functional (meth)acrylic monomers include diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, tetraethylene glycol di(meth)acrylate, hydroxypivalic acid neopentyl glycol diacrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol diacrylate, 1,3-butylene glycol di(meth)acrylate, dicyclopentaerythritol 2-hydroxybenzoate, ... Examples of the alkyl acrylate include 1,4-butanediol oligoacrylate, neopentyl glycol oligoacrylate, 1,6-hexanediol oligoacrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethoxy tri(meth)acrylate, trimethylolpropane propoxy tri(meth)acrylate, pentaerythritol tri(meth)acrylate, glyceryl propoxy tri(meth)acrylate, trimethylolpropane trimethacrylate, trimethylolpropane ethylene oxide adduct triacrylate, glycerin propylene oxide adduct triacrylate, and pentaerythritol tetraacrylate.

[0040] The primer layer preferably contains an active energy ray-curable resin or a thermosetting resin, and more preferably contains an active energy ray-curable resin. Any resin having active energy ray curability can be used as the active energy ray-curable resin. Examples of active energy ray-curable resins include (meth)acrylate polymers, more specifically, epoxy (meth)acrylate polymers and polyester (meth)acrylate polymers. Polymers having a (meth)acryloyl group, such as (meth)acrylate polymers having a (meth)acryloyl group, are particularly preferred. More specifically, examples include epoxy (meth)acrylate polymers having a (meth)acryloyl group and polyester (meth)acrylate polymers having a (meth)acryloyl group. Active energy ray-curable resins are readily available from various companies. In this specification, "(meth)acrylate" refers to methacrylate and / or acrylate, and "(meth)acryloyl group" refers to methacryloyl and / or acryloyl groups. Other similar descriptions are also interpreted as described above.

[0041] Epoxy (meth)acrylate polymer The active energy ray curable resin may be, for example, an epoxy (meth)acrylate polymer. Among them, an epoxy (meth)acrylate polymer having a (meth)acryloyl group is preferred. A synthesis example of an epoxy (meth)acrylate is shown in formula (1). Epoxy (meth)acrylate can be obtained by adding acrylic acid or methacrylic acid having an unsaturated bond to an epoxy compound. (In formula (1), R is an alkyl group having 1 to 12 carbon atoms or a hydrogen atom, and the alkyl group may be substituted with one or more substituents selected from the group consisting of an epoxy group, a hydroxyl group, an acryloyl group, and a methacryloyl group; and R' is a methyl group or a hydrogen atom.)

[0042] An epoxy (meth)acrylate polymer can be obtained, for example, by copolymerizing (meth)acrylic acid and (meth)acrylic acid glycidyl ether to synthesize an epoxy resin having a (meth)acrylate skeleton, and then adding acrylic acid, methacrylic acid, etc. to the epoxy resin. An example of the synthesis is shown in formula (2).

[0043] Suitable epoxy (meth)acrylate polymers include, for example, those having repeating units represented by formula (I): In formula (I), m is an alkylene group having 1 to 4 carbon atoms or a single bond; n is an alkyl group having 1 to 4 carbon atoms or a hydrogen atom; p is a single bond or an alkylene group having 1 or 2 carbon atoms; and q is an alkyl group having 1 to 12 carbon atoms which may have one or more substituents selected from the group consisting of an epoxy group, a hydroxyl group, an acryloyl group, and a methacryloyl group, or a hydrogen atom.

[0044] In the above formula (I), preferably, m is an alkylene group having 1 or 2 carbon atoms; n is an alkyl group having 1 or 2 carbon atoms; p is a single bond or a methylene group; and q is an alkyl group having 1 to 6 carbon atoms which may have one or more substituents selected from the group consisting of epoxy groups, hydroxyl groups, and acryloyl groups, or a hydrogen atom. More preferably, m is a methylene group; n is a methyl group; p is a single bond; and q is an alkyl group having 5 or less carbon atoms which may have one or more substituents selected from the group consisting of methyl groups and epoxy groups, or an alkyl group having 8 or less carbon atoms which may have one or more substituents selected from hydroxyl groups and acryloyl groups.

[0045] Specific examples of the repeating unit represented by formula (I) include those represented by the following formulae (II-a), (II-b) and (II-c).

[0046] Polyester (meth)acrylate polymer The polymer having a (meth)acryloyl group may be a polyester (meth)acrylate polymer. Examples of polyester (meth)acrylate polymers include polymers obtained by a dehydration condensation reaction of (meth)acrylic acid, a polybasic carboxylic acid (anhydride), and a polyol. Examples of polybasic carboxylic acid (anhydride) used in such a dehydration condensation reaction include succinic acid (anhydride), adipic acid, maleic acid (anhydride), itaconic acid (anhydride), trimellitic acid (anhydride), pyromellitic acid (anhydride), hexahydrophthalic acid (anhydride), phthalic acid (anhydride), isophthalic acid, and terephthalic acid. Examples of polyols used in the dehydration condensation reaction include 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyric acid, trimethylolpropane, ditrimethylolpropane, pentaerythritol, and dipentaerythritol.

[0047] Specific examples of polyester (meth)acrylate polymers include Aronix M-6100, Aronix M-7100, Aronix M-8030, Aronix M-8060, Aronix M-8530, and Aronix M-8050 (all trade names of polyester (meth)acrylate oligomers manufactured by Toagosei Co., Ltd.), Laromer PE44F, Laromer LR8907, Laromer PE55F, Laromer PE46T, and Laromer LR8800 (all trade names of polyester (meth)acrylate oligomers manufactured by BASF), Ebecryl 80, Ebecryl 657, Ebecryl 800, Ebecryl 450, and Ebecryl 657. 1830, Ebecryl 584 (all of which are trade names of polyester (meth)acrylate oligomers manufactured by Daicel U.C.B. Co., Ltd.), Photomer RCC13-429, Photomer 5018 (all of which are trade names of polyester (meth)acrylate oligomers manufactured by San Nopco Ltd.), and the like.

[0048] The primer composition used in the present invention may contain a surface modifier. Surface modifiers include leveling agents, light stabilizers, ultraviolet absorbers, and other agents that modify the surface performance of the primer layer. Preferred leveling agents include silicone-based leveling agents, acrylic-based leveling agents, and fluorine-based leveling agents. Examples of leveling agents include polyether-modified polyalkylsiloxanes, polyether-modified siloxanes, polyester-modified hydroxyl-containing polyalkylsiloxanes, polyether-modified polydimethylsiloxanes having alkyl groups, modified polyethers, and silicone-modified acrylics. The content of the leveling agent is preferably 0.01 to 3 parts by mass, more preferably 0.01 to 1 part by mass, per 100 parts by mass of the (meth)acryloyl polymer contained in the primer composition.

[0049] As the silicone-based leveling agent, commercially available products can be used, for example, BYK-300, BYK-302, BYK-306, BYK-307, BYK-310, BYK-313, BYK-315N, BYK-320, BYK-322, BYK-323, BYK-325, BYK-326, BYK-330, BYK-331, BYK-333, BYK-342, BYK-370, BYK-375, BYK-377, BYK-378, BYK-3760 (manufactured by BYK Corporation); Disparlon 1711EF, Disparlon 1761, Disparlon LS-001, Disparlon LS-050, Disparlon LS-280, Disparlon LS-460, Disparlon LS-480 (manufactured by Kusumoto Chemicals Co., Ltd.); Tego Flow 425, Tego Glide 100, Tego Glide 110, Tego Glide 130, Tego Glide 406, Tego Glide 420, Tego Glide 432, Tego Glide 435, Tego Glide 440, Tego Glide 450, Tego Glide 482, Tego Glide 485, Tego Glide ZG400, Tego wet KL245, Tego wet 250, Tego wet 260, Tego wet 265, Tego Wet 270, Tego Wet 280 (manufactured by Evonic Tego Chemie), etc. These may be used alone or in combination of two or more.

[0050] As the acrylic leveling agent, commercially available products can be used, and examples thereof include BYK-350, BYK-354, BYK-355, BYK-356, BYK-358N, BYK-361N, BYK-392, BYK-394, and BYK-3441 (manufactured by BYK Corporation); Disparlon LF-1983, Disparlon LF-1984, LF-1985, Disparlon UVX-35, and Disparlon UVX-36 (manufactured by Kusumoto Chemicals Co., Ltd.); Tego Flow 300, Tego Flow 370, Tego Flow ATF2, and Tego Flow ZFS460. These may be used alone or in combination of two or more.

[0051] Other types of leveling agents that can be used include commercially available products such as BYK-399, BYK-3440, BYK-3550, BYK-3560, BYK-3565, BYK-SILCLEAN 3700, BYK-SILCLEAN 3701, and BYKETOL-OK (manufactured by BYK Corporation); Disparlon UVX-272, Disparlon UVX-2285, Disparlon LHP-810, Disparlon NSH-8430HF, Disparlon LHP-90, Disparlon LHP-91, Disparlon LHP-95, and Disparlon LHP-96 (manufactured by Kusumoto Chemicals Co., Ltd.). These may be used alone or in combination of two or more.

[0052] As the fluorine-based leveling agent, commercially available fluorine-based leveling agents can be used. Examples of commercially available fluorine-based leveling agents include leveling agents of the Optool series manufactured by Daikin Industries, Ltd. ("DSX" and "DAC-HP"), leveling agents of the Surflon series manufactured by AGC Seimi Chemical Co., Ltd. ("S-242", "S-243", "S-420", "S-611", "S-651", "S-386", etc.), leveling agents of the BYK series manufactured by BYK Japan K.K. ("BYK-340", etc.), leveling agents of the AC series manufactured by Algin Chemie ("AC 110a", "AC 100a", etc.), and leveling agents of the Megafac series manufactured by DIC Corporation ("Megafac F-114", "Megafac F-410", "Megafac F-444", "Megafac EXP", etc.). TP-2066", "Megafac F-430", "Megafac F-472SF", "Megafac F-477", "Megafac F-552", "Megafac F-553", "Megafac F-554", "Megafac F-555", "Megafac R-94", "Megafac RS-72-K", "Megafac RS-75", "Megafac F-556", "Megafac EXP TF-1367", "Megafac EXP TF-1437", "Megafac F-558", "Megafac EXPTF-1537, etc.), FC series leveling agents manufactured by Sumitomo 3M Limited (FC-4430, FC-4432, etc.), Ftergent series leveling agents manufactured by Neos Corporation (Ftergent 100, Ftergent 100C, Ftergent 110, Ftergent 150, Ftergent 150CH, Ftergent A-K, Ftergent 501, Ftergent 250, Ftergent 251, Ftergent 222F, Ftergent 208G). , "Ftergent 300", "Ftergent 310", "Ftergent 400SW", "Ftergent 602A", "Ftergent 650AC", "Ftergent 681A", "Ftergent 684A", etc.), and the PF series leveling agents manufactured by Kitamura Chemical Industries Co., Ltd. ("PF-136A", "PF-156A", "PF-151N", "PF-636", "PF-6320", "PF-656", "PF-6520", "PF-651", "PF-652", "PF-3320", etc.).

[0053] Examples of light stabilizers that can be used include hindered amine compounds such as Tinuvin 123 (manufactured by BASF), Tinuvin 770DF (manufactured by BASF), Tinuvin 144 (manufactured by BASF), and LA-81 (manufactured by ADEKA). Examples of ultraviolet absorbers that can be used include DAINSORB-TO (manufactured by Daiwa Chemical Industry Co., Ltd.), Tinuvin 405 (manufactured by BASF), Tinuvin 477 (manufactured by BASF), Tinuvin 479 (manufactured by BASF), Tinuvin 928 (manufactured by BASF), and UVA-903KT (manufactured by BASF).

[0054] The primer composition used in the present invention may contain a photopolymerization initiator. In this specification, the photopolymerization initiator refers to a photoradical generator.

[0055] The photopolymerization initiator that can be used in the present invention is preferably active energy ray-curable or heat-curable, more preferably active energy ray-curable, and particularly preferably ultraviolet-curable. Examples of photopolymerization initiators that can be used include IRGACURE 184 (1-hydroxycyclohexylphenyl ketone), IRGACURE 1173 (2-hydroxy-2-methyl-1-phenylpropan-1-one), IRGACURE TPO (2,4,6-trimethylbenzoyldiphenylphosphine oxide), IRGACURE 819 (bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide), and EsacureONE (oligo(2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone). Among these, EsacureOne is preferred as the photopolymerization initiator from the viewpoint of heat resistance. The content of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 7 parts by mass, and particularly preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the (meth)acryloyl polymer contained in the primer composition.

[0056] The primer composition used in the present invention may contain one or more monomers. Examples of the monomers that can be used in the present invention include monofunctional acrylic monomers such as Light Acrylate IAA (Kyoeisha Chemical Co., Ltd.), Light Acrylate PO-A (Kyoeisha Chemical Co., Ltd.), Light Acrylate IB-XA (Kyoeisha Chemical Co., Ltd.), HOA-MS(N) (Kyoeisha Chemical Co., Ltd.), and Light Acrylate 9EG-A (Kyoeisha Chemical Co., Ltd.), and bifunctional acrylic monomers such as Light Acrylate 1.6HX-A (Kyoeisha Chemical Co., Ltd.), and Light Acrylate DCP- Examples of suitable acrylic monomers include Light Acrylate BP-4A (manufactured by Kyoeisha Chemical Co., Ltd.), Light Acrylate BP-4EAL (manufactured by Kyoeisha Chemical Co., Ltd.), and Light Acrylate BP-4PA (manufactured by Kyoeisha Chemical Co., Ltd.), and examples of suitable polyfunctional acrylates include Light Acrylate TMP-A (manufactured by Kyoeisha Chemical Co., Ltd.), Light Acrylate PE-3A (manufactured by Kyoeisha Chemical Co., Ltd.), Light Acrylate PE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), and Light Acrylate DPE-6A (manufactured by Kyoeisha Chemical Co., Ltd.), and the above-mentioned acrylic monomers can be preferably used. The content of the monomer is preferably more than 0% by mass and not more than 50% by mass, and more preferably more than 0% by mass and not more than 30% by mass, based on the total mass of the primer composition.

[0057] The method for forming the primer layer is not particularly limited, but for example, the primer layer can be formed by applying a primer composition onto a layer located below the primer layer and then photopolymerizing the applied composition.

[0058] The method for applying the primer composition is not particularly limited, and known methods can be used, such as spin coating, dipping, spraying, slide coating, bar coating, roll coating, gravure coating, meniscus coating, flexographic printing, screen printing, beat coating, and sieving.

[0059] The lamp used for light irradiation in photopolymerization has an emission distribution with a light wavelength of 420 nm or less, and examples thereof include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, etc. Among these, high-pressure mercury lamps or metal halide lamps are preferred because they efficiently emit light in the active wavelength region of the initiator and do not emit much short-wavelength light that would reduce the viscoelastic properties of the resulting polymer due to crosslinking, or much long-wavelength light that would heat and evaporate the reaction composition.

[0060] To improve the adhesion of the primer layer, the coated surface may be pretreated by known methods such as sandblasting, solvent treatment, corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone treatment, and ultraviolet treatment.

[0061] The thermoformable laminate of the present invention can be subjected to one or more of anti-reflection treatment, anti-fouling treatment, anti-static treatment, weather resistance treatment, and anti-glare treatment on one or both sides. The methods for the anti-reflection treatment, anti-fouling treatment, anti-static treatment, weather resistance treatment, and anti-glare treatment are not particularly limited, and known methods can be used. Examples include a method of applying a reflection-reducing coating, a method of vapor-depositing a dielectric thin film, and a method of applying an anti-static coating.

[0062] <Adhesive Layer> The adhesive layer is provided between the primer layer and the backing material. One feature of the present invention is that the adhesive layer is made of a two-component curing composition containing a polyester adhesive and an isocyanate curing agent, and the content of the isocyanate curing agent is 2 to 20 parts by mass per 100 parts by mass of the polyester adhesive contained in the adhesive layer. If the content of the isocyanate curing agent is less than 2 parts by mass per 100 parts by mass of the polyester adhesive contained in the adhesive layer, the adhesive strength after a moist heat test will decrease, causing lifting or peeling. If the content of the isocyanate curing agent is more than 20 parts by mass, the initial adhesive strength will decrease. The content of the isocyanate curing agent is preferably 3 to 15 parts by mass, more preferably 4 to 10 parts by mass per 100 parts by mass of the polyester adhesive contained in the adhesive layer.

[0063] The polyester adhesive used in the present invention may be a commercially available product, and preferred examples thereof include TM-K51, TM-K76, and TM-K55 manufactured by Toyo-Morton Co., Ltd. The isocyanate curing agent used in the present invention may be a commercially available product, and preferred examples thereof include CAT-RT85, CAT-RT32, and CAT-RT1 manufactured by Toyo-Morton Co., Ltd.

[0064] The adhesive layer may contain an adhesive other than a polyester-based adhesive, as long as the effects of the present invention are not impaired. Such adhesives are made of resins such as acrylic resins, urethane resins, epoxy resins, ethylene-vinyl acetate copolymer resins (EVA), vinyl resins (vinyl chloride, vinyl acetate, vinyl chloride-vinyl acetate copolymer resins), styrene-ethylene-butylene copolymer resins, polyvinyl alcohol resins, polyacrylamide resins, polyacrylamide resins, isobutylene rubber, isoprene rubber, natural rubber, SBR, NBR, and silicone rubber. These resins may be used by dissolving them in a solvent, or may be used without a solvent, as appropriate.

[0065] The thickness of the adhesive layer is not particularly limited. For example, the thickness of the adhesive layer is preferably 2 μm or more, more preferably 4 μm or more. The thickness of the adhesive layer is preferably 25 μm or less, more preferably 20 μm or less. When the thickness of the adhesive layer is within the above range, the obtained thermoforming laminate has even better appearance and adhesiveness when bonded.

[0066] The adhesive layer may be provided with a coloring pigment to impart design properties. The adhesive layer may also be blended with an antistatic agent or the like to impart functionality such as antistatic properties. This can improve the adhesive layer's suitability for lamination.

[0067] The method for forming the adhesive layer is not particularly limited. For example, the adhesive layer may be formed by using a roll coater or the like to apply a resin solution (two-component curing composition) that constitutes the adhesive layer, dissolved in an appropriate solvent, to a backer material, and then laminating the backer material with the adhesive layer formed thereon to the primer layer so that the adhesive layer and the primer layer are in contact with each other. Alternatively, a ready-made product in which an adhesive layer is provided on a backer material may be used. The method for forming the adhesive layer may be selected appropriately depending on the characteristics of the polyester adhesive and isocyanate curing agent used.

[0068] In the present invention, after the two-component curing composition is cured, the adhesive strength [N / 25 mm] required to peel the substrate layer from the backing material at a peel speed of 30 mm / min and a peel angle of 90° is preferably 4.0 [N / 25 mm] or more, more preferably 6.0 [N / 25 mm] or more. The upper limit is typically about 25 [N / 25 mm]. Furthermore, in the present invention, the adhesive strength [N / 25 mm] after a moist heat test performed under conditions of 85°C and 85% RH for 500 hours is preferably 1.5 [N / 25 mm] or more, more preferably 4.0 [N / 25 mm] or more. The upper limit is typically about 20 [N / 25 mm]. These initial adhesive strengths and adhesive strengths after the moist heat test can be measured by the method described in the Examples below.

[0069] <Backer Material> In the thermoforming laminate of the present invention, a backer material (backing sheet) is provided on the adhesive layer. The backer material is suitably provided when a film insert method is adopted when producing the thermoforming laminate. The backer material is not particularly limited. As an example, the backer material may be a polymer sheet that can be thermoformed, and is preferably an ABS sheet, a polyacrylic sheet, a polypropylene sheet, a polyethylene sheet, a polycarbonate sheet, an A-PET sheet, a PET-G sheet, a polyvinyl chloride (PVC) sheet, a polyamide sheet, or the like.

[0070] The backer material may be formed of multiple layers having different compositions. In the present invention, it is preferable to use a backer material consisting of a layer containing a polycarbonate resin and a layer containing an acrylic resin. The backer material consisting of multiple layers is not limited to a two-layer structure, and may be three or more layers. For example, when using a backer material containing a layer containing a polycarbonate resin and a layer containing an acrylic resin, it is preferable that an adhesive layer is laminated on the layer containing the acrylic resin. Using a multi-layered backer material containing a layer containing a polycarbonate resin and a layer containing an acrylic resin is preferable because it facilitates processing and molding.

[0071] The thickness of the backer material is not particularly limited. For example, from the viewpoint of formability in compression molding or the like, the thickness of the backer material is preferably 0.05 to 5 mm, and more preferably 0.1 to 3 mm.

[0072] The backing material may be subjected to a desired surface treatment. The surface treatment is not particularly limited. Examples of the surface treatment include matte, satin, embossed, hairline, and various patterns.

[0073] The backer material may be one on which an adhesive layer is already provided, or an adhesive layer may be formed on the backer material, and the adhesive layer may be attached to the primer layer so that the adhesive layer is in contact with the primer layer.

[0074] <Printed Layer> The thermoformable laminate of the present invention may have a printed layer (e.g., a printed layer formed by gravure printing, screen printing, wet coating, etc.) between the primer layer and the adhesive layer. Examples of methods for forming the printed layer include a method in which a desired design is printed directly on the primer layer by gravure printing or the like and then heated and dried to form a printed layer, and a method in which a printed layer formed by printing on a transfer sheet such as a biaxially oriented PET film is transferred to the thermoformable laminate by a method such as heat transfer. For example, printing can be performed using polyester-based, polycarbonate-based, acrylic-based, or urethane-based printing inks. In particular, if there is a problem with adhesion to the primer layer, it is possible to improve adhesion by surface modification using surface treatments such as plasma, ion etching, or corona discharge. Another example is a method in which a metal layer, metal oxide layer, etc. is formed on the primer layer using physical vapor deposition or chemical vapor deposition to form a printed layer.

[0075] The pattern of the printing layer is not particularly limited, and may be the pattern of the material of the printing layer itself, or may be a picture, letter, etc. Examples of the pattern include wood grain, stone grain, cloth grain, sand grain, woven grain, bark grain, geometric patterns, letters, tiled patterns, brickwork patterns, marquetry patterns, patchwork patterns, hairline patterns, solid wood patterns, patterned patterns, and Japanese paper patterns.

[0076] The color of the printed layer is not particularly limited and may be the color of the material of the printed layer itself or the color of a colorant. Examples of the color include black, white, red, blue, green, yellow, etc., as well as metallic colors, polarized colors, and structural colors. The printed layer may have a gloss or luster, or may be matte, such as a metallic tone, piano black tone, carbon tone, satin tone, or pearl tone.

[0077] The thickness of the printed layer may be 0.01 to 30 μm. The above thickness may be the thickness when the printed layer is formed by printing or vapor deposition. When the pattern of the printed layer is the pattern of the material of the printed layer itself, the article itself can be used as the printed layer, so the thickness (size) of the printed layer is not limited at all.

[0078] The printed layer can be formed by methods such as printing, coating, plating, vapor deposition, sputtering, ion plating, molding, polishing, and etching.

[0079] Examples of the printing method include offset printing, gravure rotary printing, screen printing, roll coating, spray coating, and flexographic printing. The printing ink used for the printing can be a mixture of a binder with an appropriate amount of a pigment, a solvent, a stabilizer, a plasticizer, a catalyst, a curing agent, etc. Examples of the binder that can be used include polyurethane resins, vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-vinyl acetate-acrylic copolymer resins, chlorinated polypropylene resins, acrylic resins, polyester resins, polyamide resins, butyral resins, polystyrene resins, nitrocellulose resins, and cellulose acetate resins, as well as resin compositions thereof.

[0080] The thermoforming laminate of the present invention is then processed into an appropriate three-dimensional shape to produce a molded article. The molding method for the molded article is not particularly limited. Examples of molding methods include vacuum molding and TOM (Three Dimension Overlay Method) molding. In TOM molding, the thermoforming laminate is applied to a previously prepared adherend and softened by heat, thereby being integrally molded to conform to the adherend. On the other hand, in vacuum molding, the thermoforming laminate is heated and softened by a heater. The heated thermoforming laminate is then pressed against a mold having a desired three-dimensional shape while being vacuum-suctioned, and is deformed to conform to the shape of the three-dimensional molded article.

[0081] The present invention will be specifically described below with reference to examples, although the present invention is not limited to these examples in any way.

[0082] Example 1 To 100 parts by mass of ultraviolet-curable (meth)acryloyl polymer (MAP-7000, manufactured by Negami Chemical Industrial Co., Ltd.), 3 parts by mass of photopolymerization initiator ESACURE-ONE (manufactured by DKSH Japan Co., Ltd.) and 1 part by mass of silicone leveling agent BYK-3565 (manufactured by BYK Japan Co., Ltd.) were added. Subsequently, PGM (polypropylene glycol monomethyl ether) was added as a dilution solvent to a solids concentration of 15% by mass, and the mixture was stirred to obtain a primer composition. As a substrate layer, DF02U (manufactured by Mitsubishi Gas Chemical Company, Inc., thickness 0.125 mm), a two-layer product of bisphenol A polycarbonate resin and PMMA (methyl methacrylate), was prepared. The primer composition obtained above was applied to the bisphenol A polycarbonate resin side of the substrate layer. The application process was performed using a #0.5 wire-wound rod, and the applied primer composition was dried at 80°C for 1 minute. Thereafter, an ultraviolet irradiator (Heraeus) was used to irradiate the light at 500 mJ / cm ２ The substrate was irradiated with ultraviolet light of 100 .mu.m / s to form a primer layer on the bisphenol A polycarbonate resin side of the substrate layer. The resulting primer layer had a thickness of 0.3 μm. 100 parts by mass of a polyester adhesive (TM-K51 manufactured by Toyo-Morton Co., Ltd.) was mixed with 4 parts by mass of an isocyanate curing agent (CAT-RT85 manufactured by Toyo-Morton Co., Ltd.), and ethyl acetate was added as a dilution solvent to a solids concentration of 30% by mass. The mixture was stirred to obtain a two-component curing composition. DF02U (manufactured by Mitsubishi Gas Chemical Company, Inc., thickness 0.254 mm), a two-layer product of bisphenol A polycarbonate resin and PMMA (methyl methacrylate), was prepared as a backer material. The two-component curing composition obtained above was applied to the PMMA side of the backer material. The application process was performed using a #6.0 wire-wound rod, and the applied two-component curing composition was dried at 80°C for 1 minute to form an adhesive layer on the PMMA side of the backer material. The adhesive layer and the primer layer obtained above were then dry laminated using a laminator MP-630A manufactured by MCK Corporation. The resulting laminate was then heated at 60°C in an explosion-proof air dryer for 3 days for thermal curing, yielding a thermoforming laminate. The resulting adhesive layer had a thickness of 10 μm.

[0083] Examples 2 and 3 Thermoforming laminates were prepared in the same manner as in Example 1, except that the thickness of the primer layer was changed as shown in Table 1 below.

[0084] (Examples 4 to 6) Thermoforming laminates were produced in the same manner as in Example 1, except that the content of the isocyanate-based curing agent was changed as shown in Table 1 below and the film thickness of the primer layer was changed as shown in Table 1 below.

[0085] Examples 7 and 8 Thermoforming laminates were prepared in the same manner as in Example 2, except that the isocyanate-based curing agent (CAT-RT32 manufactured by Toyo-Morton Co., Ltd.) shown in Table 1 below was used in the parts by mass shown in Table 1 below instead of the isocyanate-based curing agent (CAT-RT85 manufactured by Toyo-Morton Co., Ltd.).

[0086] Examples 9 and 10 Thermoforming laminates were prepared in the same manner as in Example 2, except that 100 parts by mass of a polyester adhesive (TM-K76 manufactured by Toyo-Morton Co., Ltd.) shown in Table 1 below was used, and an isocyanate curing agent (CAT-RT32 manufactured by Toyo-Morton Co., Ltd.) was used in an amount shown in Table 1 below.

[0087] Examples 11 and 12 A thermoforming laminate was prepared in the same manner as in Example 1, except that a thermosetting acrylic resin, SHP470-FT2050 manufactured by Momentive Corporation, was used as the primer composition instead of the ultraviolet-curable (meth)acryloyl polymer (MAP-7000 manufactured by Negami Chemical Industrial Co., Ltd.), and the primer composition was applied to a thickness of the primer layer shown in Table 1 below, followed by curing at 130°C for 30 minutes.

[0088] Examples 13 to 15 Thermoforming laminates were prepared in the same manner as in Example 2, except that the thickness of the adhesive layer was changed as shown in Table 2 below.

[0089] (Examples 16 to 18) Thermoforming laminates were produced in the same manner as in Example 2, except that a 2 μm printed layer was laminated as the printed layer between the primer layer and the adhesive layer using a solvent-based ink ("LioAlpha (registered trademark) R641 White" manufactured by Toyo Ink Co., Ltd.) and the film thickness of the adhesive layer was set as shown in Table 2 below.

[0090] Comparative Examples 1 and 2 Thermoformable laminates were prepared in the same manner as in Example 4, except that the thickness of the primer layer was changed as shown in Table 2 below.

[0091] Comparative Example 3 A thermoforming laminate was produced in the same manner as in Example 3, except that the isocyanate-based curing agent was used in the parts by mass shown in Table 2 below.

[0092] Comparative Example 4 A thermoforming laminate was prepared in the same manner as in Example 9, except that the isocyanate-based curing agent was used in the parts by mass shown in Table 2 below.

[0093] Comparative Example 5 A thermoforming laminate was produced in the same manner as in Example 11, except that the isocyanate-based curing agent was used in the parts by mass shown in Table 2 below and the film thickness of the primer layer was changed as shown in Table 2 below.

[0094] Comparative Example 6 A thermoforming laminate was produced in the same manner as in Example 16, except that the isocyanate-based curing agent was used in the amount of parts by mass shown in Table 2 below and the thickness of the primer layer was changed as shown in Table 2 below.

[0095] Comparative Example 7 A thermoforming laminate was produced in the same manner as in Example 16, except that the thickness of the primer layer was changed as shown in Table 2 below.

[0096] The thermoforming laminates prepared as described above were evaluated for initial adhesive strength and long-term adhesive strength stability as follows. The results are shown in Tables 1 and 2. The thickness of the primer layer was measured as follows.

[0097] <Method for Measuring Primer Layer Thickness> The thickness of the primer layer was measured using a film thickness measurement system F-20 (manufactured by Filmetrics Inc.).

[0098] <Appearance Evaluation Criteria> After producing a thermoforming laminate, the appearance was visually inspected and evaluated according to the following evaluation criteria. ∘: No change in appearance was observed across the entire thermoforming laminate. Δ: Slight whitening or slight cracks occurred in the base layer, but these were at a level that would not pose a problem in practical use. ×: Significant whitening of the appearance or large cracks occurred in the base layer.

[0099] <90-degree peel test> An autograph AGS-X manufactured by Shimadzu Corporation was used. Using a 25 mm x 210 mm thermoforming laminate as a test piece, peel strength measurements were performed in accordance with "JIS K 6854-1 - Adhesives - Peel adhesion strength test method - Part 1: 90-degree peel" at a measurement width of 25 mm and a peel speed of 30 mm / min to evaluate the adhesive strength between the substrate layer and the backing material. The adhesive strength was evaluated from the 90-degree peel test value according to the following evaluation criteria: ○: Adhesive strength of 6.0 N / 25 mm or more △: Adhesive strength of 4.0 N / 25 mm or more but less than 6.0 N / 25 mm ×: Adhesive strength of less than 4.0 N / 25 mm

[0100] <90-degree peel test after moist heat test> A test was carried out for 500 hours (temperature: 85°C, humidity: 85% RH) using a PL-3KPH manufactured by ESPEC Corporation. After the test, the long-term stability of adhesive strength was evaluated in the same manner as in the 90-degree peel test described above. The adhesive strength was evaluated according to the following evaluation criteria from the value of the 90-degree peel test after the moist heat test. ○: Adhesive strength of 4.0 N / 25 mm or more △: Adhesive strength of 1.5 N / 25 mm or more but less than 4.0 N / 25 mm ×: Adhesive strength of less than 1.5 N / 25 mm

[0101]

Claims

1. A thermoforming laminate comprising a substrate layer, a primer layer, an adhesive layer, and a backing material in this order, wherein the primer layer has a thickness of 0.2 to 1.0 μm, the adhesive layer is made of a two-component curing composition containing a polyester adhesive and an isocyanate curing agent, and the content of the isocyanate curing agent is 2 to 20 parts by mass per 100 parts by mass of the polyester adhesive contained in the adhesive layer.

2. The thermoformable laminate of claim 1, wherein the backer material comprises a thermoplastic resin.

3. The thermoformable laminate according to claim 2, wherein the thermoplastic resin comprises a polycarbonate resin.

4. The thermoforming laminate according to any one of claims 1 to 3, wherein the backing material comprises a layer containing a polycarbonate resin and a layer containing an acrylic resin.

5. The thermoforming laminate according to claim 4, wherein the adhesive layer is disposed on the side of the layer containing the acrylic resin.

6. The thermoforming laminate according to any one of claims 1 to 5, wherein the substrate layer comprises a polycarbonate resin.

7. The thermoforming laminate according to any one of claims 1 to 6, wherein the substrate layer comprises a layer containing a polycarbonate resin and a layer containing an acrylic resin.

8. The thermoforming laminate according to claim 7, wherein the primer layer is disposed on the side of the layer containing the polycarbonate resin.

9. The thermoforming laminate according to any one of claims 1 to 8, wherein the primer layer contains an active energy ray-curable resin having a (meth)acryloyl group or a thermosetting resin having a (meth)acryloyl group.

10. The thermoforming laminate according to any one of claims 1 to 9, wherein the adhesive layer has a thickness of 2 to 25 µm.

11. A thermoforming laminate according to any one of claims 1 to 10, wherein after the two-component curing composition has cured, the adhesive strength [N / 25 mm] required to peel the base layer from the backing material at a peel speed of 30 mm / min and a peel angle of 90° is 4.0 [N / 25 mm] or more, and the adhesive strength [N / 25 mm] after a moist heat test conducted under conditions of 85°C, 85% RH for 500 hours is 1.5 [N / 25 mm] or more.

12. The thermoforming laminate according to any one of claims 1 to 11, which comprises a printed layer between the primer layer and the adhesive layer.

13. A molded article obtained by molding the thermoforming laminate according to any one of claims 1 to 12.

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