Decorative sheet

Abstract

To provide a decorative sheet that can clear a required non-flammability standard when attached to an interior material of a moving body and that suppresses or prevents an occurrence of warping.SOLUTION: A decorative sheet 10 of the present invention includes a core layer 11 and a surface layer 12, which are laminated in this order, and the decorative sheet 10 satisfies as follows: the surface layer 12 is composed of a resin composition containing a thermosetting resin and a support substrate that supports the resin composition by being impregnated therein, and the decorative sheet 10 is used as a first test piece in a shape of a strip with a short side of 20 mm and a long side of 120 mm, and with one short side fixed so that the other short side is floating, the first test piece is left to stand in an environment of a temperature of 40°C and a relative humidity of 93% for 96 hours, and after using a position of one short side as a reference point, the first test piece is left to stand in an environment of a temperature of 70°C and a relative humidity of 10% for 24 hours, and a displacement amount X of one short side from the reference point is 7.0 mm or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a decorative sheet. [Background technology]

[0002] Conventionally, when deterioration in the appearance of interior materials in moving bodies such as trains, automobiles, aircraft, and ships is recognized due to long-term use, the interior materials themselves have been removed and new interior materials have been installed to refurbish the vehicle.

[0003] However, in this case, removing and installing the interior materials requires time and effort, and there is a problem that, particularly if the vehicle is used for public transportation and there is no spare vehicle, this will affect the timetable of the public transportation. Therefore, there was a need to renew the interior materials without requiring time and effort.

[0004] In order to solve this problem, it has been proposed in recent years to apply a decorative sheet (decorative board) with design to the surface of interior material that has been found to have deteriorated in design, without removing the material (see Patent Document 1). With this attachment method (application method), there is no need to remove the interior material that has been found to have deteriorated in design, and a new decorative sheet can be applied directly to the interior material, making it possible to renovate the interior material without requiring time and effort.

[0005] Since such interior materials are to be applied to moving bodies in public transportation, and in order to meet the "non-flammability" standards of the vehicle material combustion test, it has been proposed that they be made up of a laminate having a core layer containing a metal material with heat dissipation properties and a surface layer laminated on one side of this core layer, the surface opposite to the core layer forming the design surface, and that this surface layer be made up of a melamine resin-impregnated layer.

[0006] However, with decorative sheets having such a configuration, when moisture absorption occurs due to temperature changes caused by warm and cold differences or changes in humidity, the decorative sheet warps due to a large difference between the dimensional change rates of the core layer and the surface layer, etc. As a result, problems have arisen in that it is not possible to apply the decorative sheet with high precision to interior materials that have been found to have deteriorated, and that peeling of the decorative sheet from the interior material is observed relatively soon after application of the decorative sheet to the interior material. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-096702 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a decorative sheet that can meet the required non-flammability standards when attached to interior materials of a mobile body and that suppresses or prevents warping. [Means for solving the problem]

[0009] These objects can be achieved by the present invention as set forth in (1) to (11) below. (1) A decorative sheet composed of a laminate having a core layer having heat dissipation properties and a surface layer laminated on one side of the core layer, the surface opposite to the core layer forming a design surface, the surface layer is composed of a resin composition containing a thermosetting resin and a support substrate that supports the resin composition by being impregnated therewith; A decorative sheet characterized by satisfying the following requirement A. Requirement A: The displacement measured using the procedures (A-1) to (A-6) below is 7.0 mm or less. (A-1) The decorative sheet is used as the first test piece in the form of a strip measuring 20 mm on the short side and 120 mm on the long side. (A-2) The first test piece is fixed by clamping a range of 20 mm from the other short side with a fixing jig so that one of the short sides is floating in the air. (A-3) The first test piece fixed to the fixing jig is left to stand in an environment of a temperature of 40°C and a relative humidity of 93% for 96 hours. (A-4) The first test piece fixed to the fixing jig is placed on a flat surface, and the vertical position of one of the short sides is set as a reference point. (A-5) The first test piece fixed to the fixing jig is left to stand in an environment of a temperature of 70°C and a relative humidity of 10% for 24 hours. (A-6) The amount of displacement of one of the short sides in the vertical direction from the reference point is defined as the amount of displacement.

[0010] (2) The decorative sheet according to (1) above, wherein the surface layer satisfies the following requirement B: Requirement B: Six second test pieces, each 140 mm long and 13 mm wide, are prepared from the surface layer, and in accordance with Method B for dimensional stability (high temperature) of the thermosetting resin high-pressure decorative panel testing methods specified in JIS K 6902:2022, three of the second test pieces are subjected to a low-humidity test in which they are left to stand in a thermostatic chamber at a temperature of 70°C for 24 hours, and the remaining three second test pieces are subjected to a high-humidity test in which they are left to stand in a thermostatic chamber at a temperature of 40°C and a relative humidity of 93% for 96 hours.When the total dimensional change rate is calculated as the sum of the average longitudinal dimensional change rate of the second test pieces in the low-humidity test and the average longitudinal dimensional change rate of the second test pieces in the high-humidity test, the absolute value of the total dimensional change rate is 1.0% or less.

[0011] (3) The decorative sheet according to (1) or (2) above, wherein the resin composition contains a diallyl phthalate resin and an unsaturated polyester resin as the thermosetting resin.

[0012] (4) The decorative sheet according to any one of (1) to (3) above, wherein the content of the diallyl phthalate resin in the resin composition is 20% by weight or more and 90% by weight or less.

[0013] (5) The support substrate is porous and has a basis weight of 40 g / m 2 More than 150g / m 2 A decorative sheet according to any one of the above (1) to (4):

[0014] (6) A decorative sheet according to any one of (1) to (5) above, wherein the surface layer has an average thickness of 0.05 mm or more and 0.30 mm or less.

[0015] (7) A decorative sheet according to any one of (1) to (6) above, wherein the core layer is mainly made of a heat-dissipating material having a thermal conductivity of 10 W / m·K or more. (8) The decorative sheet according to (7) above, wherein the heat-dissipating material is a metal material.

[0016] (9) A decorative sheet according to any one of (1) to (8) above, wherein the core layer has a surface on at least the surface layer side treated with a primer using an epoxy resin.

[0017] (10) A decorative sheet according to any one of (1) to (9) above, wherein the core layer has an average thickness of 0.20 mm or more and 0.50 mm or less.

[0018] (11) The decorative sheet according to any one of (1) to (10) above, which is used by being attached to the surface of an interior material of a moving body. [Effects of the Invention]

[0019] According to the present invention, when a decorative sheet is attached to an interior material of a moving body, the required non-flammability standards can be met and warping in the decorative sheet can be accurately suppressed or prevented. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a longitudinal cross-sectional view showing an embodiment of a decorative sheet of the present invention. [Figure 2]FIG. 2 is a vertical cross-sectional view showing a method for evaluating the magnitude of warpage of the decorative sheet of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The decorative sheet of the present invention will now be described in detail with reference to preferred embodiments shown in the accompanying drawings.

[0022] (Decorative sheet 10) Fig. 1 is a longitudinal cross-sectional view showing an embodiment of the decorative sheet of the present invention, and Fig. 2 is a longitudinal cross-sectional view showing a method for evaluating the magnitude of warpage of the decorative sheet of Fig. 1. For convenience of explanation, the upper side of Fig. 1 and Fig. 2 will be referred to as "upper" and the lower side as "lower" below.

[0023] The decorative sheet 10 (decorative board) shown in Figure 1 is used to refurbish interior materials in moving bodies such as trains, automobiles, aircraft, and ships when the appearance of the interior material has deteriorated due to long-term use, etc., by attaching this decorative sheet 10 to the surface of the interior material.

[0024] This decorative sheet 10 is composed of a laminate having a core layer 11 with heat dissipation properties and a surface layer 12 laminated on one side (top side) of this core layer 11, the surface of which on the opposite side (top side) to the core layer 11 forms the design surface, and the surface layer 12 is composed of a resin composition containing a thermosetting resin and a supporting substrate that supports this resin composition by being impregnated with it, and satisfies the following requirement A.

[0025] Requirement A: The displacement X measured by the following procedures (A-1) to (A-6) is 7.0 mm or less. Figure 2 is a diagram for explaining the following procedures.

[0026] (A-1) A first test piece 100 in the shape of a strip with a short side of 20 mm and a long side of 120 mm is prepared from the decorative sheet 10.

[0027] (A-2) The first test piece 100 is fixed by clamping a range of 20 mm from the other short side 102 with a fixing jig 20 so that one short side 101 of the first test piece 100 is floating in the air. At this time, the first test piece 100 is fixed so that the surface layer 12 is positioned vertically upward, for example, as shown in FIG.

[0028] (A-3) The first test piece 100 fixed to the fixing jig 20 is left to stand for 96 hours in an environment with a temperature of 40°C and a relative humidity of 93%. As a result, the first test piece 100 absorbs moisture, and for example, warpage C1 as shown in FIG. 2 occurs.

[0029] (A-4) The first test piece 100 fixed to the fixing jig 20 is placed on the flat surface 30, and the position of one of the short sides 101 in the vertical direction is set as the reference point RP shown in FIG.

[0030] (A-5) The first test piece 100 fixed to the fixing jig 20 is left to stand for 24 hours in an environment of a temperature of 70°C and a relative humidity of 10%. As a result, the first test piece 100 that has absorbed moisture dries, and for example, as shown in FIG. 2, a warpage C2 different from the warpage C1 described above occurs.

[0031] (A-6) Measure the amount of vertical displacement of one of the short sides 101 from the reference point RP, and define this as the displacement amount X.

[0032] The decorative sheet 10 is composed of a laminate having a core layer 11 and a surface layer 12. The core layer 11 has heat dissipation properties, and the surface layer 12 is composed of a resin composition containing a thermosetting resin and a support substrate that is impregnated with the resin composition. Therefore, when the decorative sheet 10 is applied to the interior material of a mobile object, it can meet the required non-flammability standards.

[0033] Furthermore, in requirement A, the magnitude of the displacement X is set to 7.0 mm or less, thereby accurately suppressing or preventing the occurrence of warping in the decorative sheet 10. As a result, when applying the decorative sheet 10 to interior materials that have been found to be deteriorated in order to renovate the interior materials of vehicles, this application can be carried out with excellent accuracy. Furthermore, peeling of the decorative sheet 10 from the interior materials can be accurately suppressed or prevented relatively soon after application of the decorative sheet 10 to the interior materials, thereby maintaining the state in which the decorative sheet 10 is applied to the interior materials for an extended period of time. In particular, requirement A takes into consideration the effects of warping due to changes in temperature and humidity. Therefore, by satisfying requirement A, a decrease in work accuracy is sufficiently suppressed even in work environments with large changes in temperature and humidity, and a decorative sheet 10 can be realized in which peeling is sufficiently suppressed even in environments with large changes in temperature and humidity after application.

[0034] The state of the warps C1 and C2 shown in FIG. 2 is an example, and the state may be different from that shown in the drawing.

[0035] The decorative sheet 10 will now be described with respect to each part (each layer) of the laminate that constitutes it, that is, the core layer 11 and the surface layer 12 that the laminate has.

[0036] (Core layer 11) In this embodiment, when the decorative sheet 10 is attached to an interior material that has been found to have deteriorated, the core layer 11 constitutes the innermost layer located on the interior material side, i.e., the innermost layer located on the opposite side to the surface of the decorative sheet 10 that is visible to the user.

[0037] This core layer 11 has heat dissipation properties, and is preferably made primarily of a heat dissipation material having a thermal conductivity of 10 W / m·K or more.

[0038] This provides excellent heat dissipation properties to the core layer 11 and ultimately to the decorative sheet 10. As a result, the decorative sheet 10 can relatively easily meet the "non-flammability" standards of the vehicle material combustion test. In this specification, "heat dissipation" refers to the release of heat by at least one of the mechanisms of "thermal conduction," "convective heat conduction," and "thermal radiation."

[0039] Heat-dissipating materials with a thermal conductivity of 10 W / m·K or higher are not particularly limited, but include, for example, metallic materials (metals) such as silver (420 W / m·K), copper (398 W / m·K), gold (320 W / m·K), aluminum (236 W / m·K), silicon (168 W / m·K), brass (106 W / m·K), and iron (84 W / m·K), as well as ceramic materials such as boron nitride, and one or more of these can be used in combination. Among these, the heat-dissipating material is preferably a metallic material, and particularly preferably a material containing aluminum.

[0040] Examples of the core layer 11 containing such a heat-dissipating material include a resin sheet (resin layer) containing thermally conductive particles made of a heat-dissipating material, and a heat-dissipating sheet (heat-dissipating layer) made of a heat-dissipating material. However, from the viewpoints of thermal conductivity, processability, and versatility, a metal layer made of a metal material is preferably used, and an aluminum layer made of aluminum is particularly preferably used.

[0041] Here, when the core layer 11 is constructed of an aluminum layer, for example, aluminum foil or aluminum plate can be used. This can impart heat resistance and non-flammability to the core layer 11, and ultimately to the decorative sheet 10. As a result, a decorative sheet 10 can be obtained that meets the "non-flammability" standard of the vehicle material combustion test. Furthermore, excellent rigidity can be imparted to the decorative sheet 10. Thus, it is relatively easy to realize a decorative sheet 10 that satisfies the above-mentioned requirement A, i.e., a decorative sheet 10 in which the magnitude of the displacement X is set to 7.0 mm or less.

[0042] In this case, the average thickness of the core layer 11 is preferably 0.20 mm or more and 0.50 mm or less, and more preferably 0.25 mm or more and 0.45 mm or less. By setting the average thickness at or above the lower limit, excellent heat resistance and non-combustibility can be imparted to the core layer 11 and, in turn, to the decorative sheet 10. There are no particular limitations on the upper limit of the average thickness, but a larger average thickness improves heat resistance and non-combustibility, but increases the thickness and weight of the decorative sheet 10 and increases costs. For this reason, it is preferable to set the average thickness at or below the upper limit. Furthermore, by setting the average thickness within the above range, a decorative sheet 10 that satisfies requirement A can be realized relatively easily.

[0043] Furthermore, in this case, it is preferable that one or both surfaces (the surface on the surface layer 12 side) of the core layer 11 be subjected to sanding, chromate treatment, or other treatment to remove an oxide film, or a primer treatment. Among these, the primer treatment can particularly improve the adhesion between the core layer 11 and the surface layer 12.

[0044] The resin used for the primer treatment is not particularly limited, but examples thereof include epoxy resins, urethane resins, polyester resins, acrylic resins, and mixtures or copolymers thereof, with epoxy resins being preferred, as this allows the effects obtained by the primer treatment to be more pronounced.

[0045] When the core layer 11 is made of a metal layer (aluminum layer), the core layer 11 functions to conceal any interior material that has been found to be deteriorated, i.e., the attachment surface to which the decorative sheet 10 is attached. In other words, the core layer 11 functions as a concealing layer that can prevent the interior material (attachment surface) from being seen through from the surface layer 12 side, i.e., the surface side of the decorative sheet 10.

[0046] In addition, when the user views the core layer 11 from the surface layer 12 side, the core layer 11 also has the function of improving the visibility of the pattern on the surface layer 12 or changing the color depending on the combination with the surface layer 12 described below.

[0047] (Surface layer 12) In this embodiment, when the decorative sheet 10 is attached to an interior material that has been found to have deteriorated, the surface layer 12 is located as the outermost layer on the side opposite the interior material, i.e., the surface of the decorative sheet 10 that is visible to the user.

[0048] The surface layer 12 is composed of a resin composition containing a thermosetting resin and a support substrate that supports the resin composition by being impregnated with the resin composition. The surface layer 12 constitutes the design surface that is visually recognized by the user.

[0049] In this specification, the term "support substrate supporting a resin composition" refers to one or both of the following states: the resin composition is attached to the surface of the substrate (carrier) and / or impregnated into voids formed inside the porous support substrate. This allows the functionality of the supported thermosetting resin to be realized after the formation of the surface layer 12. The resin composition does not have to be uniformly distributed on the surface of the support substrate and inside the substrate.

[0050] The support substrate is in the form of a sheet. The support substrate is impregnated with a resin composition containing a thermosetting resin, and the cured resin is supported on the support substrate. This provides the support substrate, and ultimately the surface layer 12, with a suitable hardness.

[0051] The constituent materials for the support substrate are not particularly limited, but examples include pulp, linter, synthetic fiber, glass fiber, and titanium oxide-containing decorative paper containing pigments such as titanium oxide, and one or more of these can be used in combination. Among these, pulp, linter, synthetic fiber, and glass fiber are preferably used. By constructing the support substrate from these constituent materials, the above-mentioned requirement A can be satisfied relatively easily.

[0052] When the support substrate is porous, the basis weight is not particularly limited, but is, for example, 40 g / m 2 More than 150g / m 2 Preferably, it is 70 g / m or less. 2 More than 120g / m 2 It is more preferable that the basis weight is less than the lower limit. If the basis weight is less than the lower limit, depending on the constituent material of the support substrate, phenomena such as cuts and wrinkles may occur in the support substrate when the resin composition is supported on the support substrate. This may make it difficult to support the resin composition or to adjust the amount of resin composition supported on the support substrate. On the other hand, if the basis weight exceeds the upper limit, depending on the constituent material of the support substrate, unevenness may occur in the amount of resin composition supported on the support substrate, which may result in a decrease in the flexibility of the surface layer 12 and therefore the decorative sheet 10, as well as a decrease in productivity and an increase in costs.

[0053] Furthermore, the average thickness of the surface layer 12 is not particularly limited, but is preferably 0.05 mm or more and 0.30 mm or less, and more preferably 0.10 mm or more and 0.25 mm or less, for example. This allows a sufficient amount of the resin composition to be supported on the support substrate, thereby reliably satisfying the requirement A.

[0054] The support substrate having such a configuration is impregnated with a resin composition containing a thermosetting resin and supported as a cured product, thereby imparting a suitable hardness to the support substrate and, in turn, to the surface layer 12.

[0055] The amount of resin (solid content of the resin in the resin composition) impregnated into the porous support substrate is expressed as the mass ratio of the resin impregnated into the support substrate to the total mass of the support substrate and resin. The amount of resin impregnated into the decorative sheet 10 is preferably 30% by mass or more and 70% by mass or less, and more preferably 40% by mass or more and 60% by mass or less. This allows for the realization of a decorative sheet 10 that has a good balance of the necessary non-flammability, warp suppression, and suitable surface hardness.

[0056] The thermosetting resin contained in this resin composition is not particularly limited as long as it satisfies the above-mentioned requirement A. Examples include diallyl phthalate-based resins, unsaturated polyester-based resins, phenol-based resins, epoxy-based resins, benzoguanamine-based resins, urethane-based resins, alkyd-based resins, and urea-based resins, and one or more of these may be used in combination.

[0057] Among these, it is preferable that this thermosetting resin contains a diallyl phthalate-based resin, and it is even more preferable that it contains a diallyl phthalate-based resin and an unsaturated polyester-based resin, which makes it relatively easy for the decorative sheet 10 to satisfy the above-mentioned requirement A.

[0058] In addition, in the resin composition before being supported on the support substrate, the thermosetting resin is contained as a prepolymer having a thermosetting functional group. In contrast, when the resin composition is supported on the support substrate, the resin composition exists in a cured state due to heating. A cured product refers to a state in which functional groups in the thermosetting resin react with each other, that is, a state in which prepolymers are polymerized to form a polymer. Furthermore, when the thermosetting resin is a diallyl phthalate resin or an unsaturated polyester resin, the thermosetting functional group of the thermosetting resin is an unsaturated carbon-carbon double bond.

[0059] The diallyl phthalate resin may be a compound containing at least a constituent unit derived from a diallyl phthalate monomer.

[0060] Examples of the diallyl phthalate monomer include diallyl orthophthalate, diallyl isophthalate, and diallyl terephthalate, and one or more of these can be used in combination.

[0061] The unsaturated polyester resin may be a compound containing a structural unit derived from a polybasic unsaturated acid and a structural unit derived from a polyhydric alcohol. The unsaturated polyester resin may further contain a structural unit derived from a polybasic saturated acid. The unsaturated acid, saturated acid, and polyhydric alcohol may each be used alone or in combination of two or more.

[0062] The polybasic unsaturated acid is not particularly limited, and examples thereof include maleic acid, fumaric acid, itaconic acid, and phthalic acid monomers such as orthophthalic acid, isophthalic acid, and terephthalic acid. The polyhydric alcohol is not particularly limited, and examples thereof include ethylene glycol, diethylene glycol, propylene glycol, and neopentyl glycol.

[0063] In addition, as the unsaturated polyester-based resin, an air-curable unsaturated polyester-based resin can also be used. In this case, for example, the unsaturated polyester-based resin may include a structural unit derived from an aliphatic cyclic unsaturated acid such as tetrahydrophthalic acid, 3,6-endomethylenetetrahydrophthalic acid, or methyl-3,6-endomethylenetetrahydrophthalic acid as the unsaturated acid, and a structural unit derived from allyl glycidyl ether as the polyhydric alcohol.

[0064] Such an unsaturated polyester resin may be either a liquid or a solid at room temperature.

[0065] The content of the thermosetting resin in the resin composition is preferably 10% by weight to 100% by weight, more preferably 40% by weight to 90% by weight, and even more preferably 50% by weight to 80% by weight.

[0066] In this case, when the thermosetting resin contains a diallyl phthalate resin and an unsaturated polyester resin, the content of the diallyl phthalate resin in the resin composition is preferably 20% by weight or more and 90% by weight or less, more preferably 30% by weight or more and 80% by weight or less, and even more preferably 60% by weight or more and 70% by weight or less. By setting the content of the diallyl phthalate resin within the above range, it is possible to improve the adhesion between the support substrate and the resin composition, and it is also possible to relatively easily satisfy the requirement A.

[0067] Furthermore, the weight-average molecular weight of the thermosetting resin, diallyl phthalate resin or unsaturated polyester resin, is not particularly limited, but is preferably 200 to 1,000, more preferably 250 to 500. By setting the molecular weight within this range, the thermosetting resin can be impregnated into the support substrate and reliably supported. Therefore, the requirement A can be reliably satisfied. The weight-average molecular weight can be measured, for example, by GPC (gel permeation chromatography, standard substance: polystyrene equivalent).

[0068] The resin composition containing a thermosetting resin may contain a monomer constituting the thermosetting resin or an oligomer of this monomer (e.g., a polymer of two or three monomers). Specifically, when the resin composition contains a diallyl phthalate-based resin as the thermosetting resin, it may contain a diallyl phthalate-based monomer which is a constituent unit of this diallyl phthalate-based resin.

[0069] As described above, the resin composition contains a thermosetting resin, and preferably further contains a crosslinking agent that crosslinks the thermosetting resin.

[0070] By including a crosslinking agent in the resin composition, the crosslink density of the cured resin composition supported on the support substrate increases, thereby increasing the surface hardness of the cured resin composition and, in turn, the surface layer 12. This makes it possible to satisfy the requirement A relatively easily.

[0071] The crosslinking agent is appropriately selected depending on the type of thermosetting resin contained in the resin composition. Specifically, when the thermosetting resin is a diallyl phthalate resin or an unsaturated polyester resin, examples of the crosslinking agent include polyfunctional monomers having at least two polymerizable functional groups with unsaturated carbon-carbon double bonds, such as (meth)acryloyl groups and vinyl groups, and polyfunctional compounds such as polymers of these polyfunctional monomers, and these may be used alone or in combination of two or more.

[0072] Examples of polyfunctional monomers include polyfunctional (meth)acrylates such as hexanediol di(meth)acrylate, dodecanediol di(meth)acrylate, butanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, butyl di(meth)acrylate, and hexyl di(meth)acrylate. Polyfunctional compounds preferably include poly(meth)acrylates having three or more (meth)acryloyl groups in the molecule.

[0073] The content of the crosslinking agent in the resin composition is preferably 0.5 to 50 parts by weight, more preferably 10 to 47 parts by weight, and even more preferably 30 to 45 parts by weight, per 100 parts by weight of the thermosetting resin. Setting the content of the crosslinking agent within this range ensures a high crosslink density in the cured resin composition supported on the support substrate, thereby ensuring high surface hardness of the cured resin composition and, in turn, the surface layer 12. In particular, when the content of the diallyl phthalate resin in the thermosetting resin is high, preferably 60% by weight or more, more preferably 80% by weight or more, the effect obtained by setting the content of the crosslinking agent within this range can be more significantly exhibited.

[0074] Furthermore, the resin composition preferably contains a polymerization initiator. By including a polymerization initiator in the resin composition, the curing rate of the thermosetting resin in the resin composition can be increased, and therefore, the cured product of the resin composition can be formed in a relatively short time as a product impregnated into a support substrate.

[0075] The polymerization initiator is appropriately selected depending on the type of thermosetting resin contained in the resin composition. Specifically, when the thermosetting resin is a diallyl phthalate resin or an unsaturated polyester resin, examples of the polymerization initiator include benzoyl peroxide, tertiary butyl perbenzoate, dicumyl peroxide, etc., and one or more of these can be used in combination.

[0076] The content of the polymerization initiator in the resin composition is set within a range of preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, relative to 100 parts by weight of the thermosetting resin. By setting the content of the polymerization initiator within the range, the effects obtained by the resin composition containing the polymerization initiator can be reliably exhibited.

[0077] The resin composition preferably contains a crosslinking agent and a polymerization initiator in addition to the thermosetting resin, as described above, but may further contain other components.

[0078] Such other components include curing catalysts, curing accelerators, release agents, fillers, plasticizers, dispersants, thickeners, viscosity modifiers, flame retardants, colorants (pigments, dyes, etc.), antifoaming agents, preservatives, UV absorbers, depleting agents, antibacterial agents, leveling agents, silane coupling agents, etc., and these may be used alone or in combination of two or more.

[0079] Here, the method for supporting a resin composition containing a thermosetting resin on a support substrate is not particularly limited, but examples include a method in which a resin composition made into a varnish by adding a solvent is applied using a known device such as a spray device, a shower device, a kiss coater, or a comma coater, and then the resin composition is heated and dried at a temperature of about 80°C to 130°C.

[0080] After the varnish-like resin composition is applied to the support substrate and heat-dried, i.e., the surface layer 12 composed of the support substrate carrying the resin composition, preferably contains 2 to 9% by weight, and more preferably 5 to 8% by weight, of volatile matter (solvent) when the total weight of the surface layer 12 is taken as 100% by weight. This makes the surface layer 12 easier to handle and improves the resin flow of the thermosetting resin on the surface visible to the user (the surface of the surface layer 12 opposite the core layer 11) during thermoforming. This allows the decorative sheet 10 to have a good design appearance and surface gloss. Furthermore, since warping in the decorative sheet 10 can be accurately suppressed, the aforementioned requirement A can be met relatively easily.

[0081] The solvent for dissolving the thermoplastic resin in the resin composition is not particularly limited, but examples thereof include polar solvents such as water; alcoholic solvents such as methanol, ethanol, and isopropanol; ketone solvents such as methyl ethyl ketone and acetone; amide solvents such as dimethylformamide (DMF); ether solvents such as tetrahydrofuran (THF) and tetrahydropyran; and sulfoxide solvents such as dimethyl sulfoxide (DMSO). Among these, water, methanol, or methyl ethyl ketone is preferred, and methyl ethyl ketone is particularly preferred. The content of solids (all components excluding the solvent) in the solvent-containing resin composition is not particularly limited, but is preferably 30% by weight to 70% by weight, and more preferably 45% by weight to 60% by weight, relative to the solvent-containing resin composition. This improves the impregnation of the solvent-containing resin composition into the support substrate.

[0082] The surface layer 12 having such a configuration preferably satisfies the following requirement B. Requirement B: Six second test pieces, each 140 mm long and 13 mm wide, were prepared from the surface layer 12. According to JIS K 6902:2022's dimensional stability (high temperature) test method B, three of the second test pieces were subjected to a low-humidity test in which they were left in a thermostatic chamber at 70°C for 24 hours, and the remaining three were subjected to a high-humidity test in which they were left in a thermostatic chamber at 40°C and 93% relative humidity for 96 hours. The total dimensional change was calculated by adding the absolute value of the average longitudinal dimensional change of the second test pieces in the low-humidity test and the absolute value of the average longitudinal dimensional change of the second test pieces in the high-humidity test. The total dimensional change was 1.0% or less.

[0083] By satisfying requirement B, it is possible to realize a surface layer 12 in which the ratio of dimensional change due to moisture absorption accompanying temperature changes due to temperature differences and humidity changes is sufficiently small, and therefore requirement A can be satisfied relatively easily.

[0084] (adhesive layer) The decorative sheet 10 having the above-described configuration may also include an adhesive layer as an intermediate layer located between the surface layer 12 and the core layer 11. This improves the bonding strength between the surface layer 12 and the core layer 11.

[0085] The adhesive layer is selected from a single layer or two or more layers of a primer, adhesive, adhesive film, glass cloth prepreg, or other adhesive that functions as an adhesive. All of these can be general-purpose adhesives.

[0086] Furthermore, even if the adhesive layer itself does not have an adhesive effect, glass cloth, for example, can be used as the adhesive layer because it has better adhesion to both adherends than to each other. Glass cloth has good adhesion to both the thermosetting resin impregnated in the support substrate of the surface layer 12 and the primer-treated core layer 11. Therefore, by disposing the glass cloth as an intermediate layer between the surface layer 12 and the core layer 11, the glass cloth can function as an adhesive layer that bonds the surface layer 12 and the core layer 11.

[0087] The glass cloth, and further the glass cloth contained in the glass cloth prepreg, is not particularly limited, but examples thereof include woven glass fabric, nonwoven glass fabric, etc. Examples of glass constituting the glass cloth include E glass, C glass, A glass, S glass, D glass, NE glass, T glass, H glass, etc.

[0088] The adhesive is not particularly limited, and examples thereof include acrylic adhesives, urethane adhesives, epoxy adhesives, and silicone adhesives. Among these, urethane adhesives are preferred. This can improve the adhesive strength and durability of the adhesive layer while also improving its ability to adapt to changes in shape.

[0089] Conventional decorative sheets can warp due to moisture absorption caused by temperature changes due to temperature differences and humidity changes. This is thought to be due to factors such as a large difference between the dimensional change rates of the core layer and the surface layer. When this warping occurs, problems arise, such as reduced work accuracy and peeling of the decorative sheet from the interior material relatively soon after application, when applying the decorative sheet to interior materials that have been found to be deteriorated, for example, for renovation of interior materials for moving objects such as trains, automobiles, aircraft, and ships.

[0090] In contrast to this, in this embodiment, the decorative sheet 10 satisfies requirement A that the displacement X measured by the following procedures (A-1) to (A-6) be 7.0 mm or less.

[0091] (A-1) The decorative sheet 10 is formed into a first test piece 100 in the shape of a strip with a short side of 20 mm and a long side of 120 mm. (A-2) The first test piece 100 is fixed by clamping a range of 20 mm from the other short side 102 with a fixing jig 20 so that one short side 101 of the first test piece 100 floats in the air. (A-3) The first test piece 100 fixed to the fixing jig 20 is left standing in an environment of a temperature of 40°C and a relative humidity of 93% for 96 hours. (A-4) The first test piece 100 fixed to the fixture 20 is placed on the flat surface 30, and the position of one short side 101 in the vertical direction is set as the reference point RP. (A-5) The first test piece 100 fixed to the fixing jig 20 is left standing in an environment of a temperature of 70°C and a relative humidity of 10% for 24 hours. (A-6) The amount of displacement of one short side 101 in the vertical direction from the reference point RP is defined as the displacement amount X.

[0092] This configuration makes it possible to realize a decorative sheet 10 that warps little, regardless of the humidity environment. This allows the decorative sheet 10 to be attached to the interior material with high precision. Specifically, it is possible to accurately suppress or prevent the occurrence of wrinkles and the like in the decorative sheet 10. Furthermore, it is possible to accurately suppress or prevent the decorative sheet 10 from peeling off from the interior material relatively soon after attachment, allowing the decorative sheet 10 to remain attached for a long period of time.

[0093] In the present invention, the displacement X may be 7.0 mm or less, preferably 3.0 mm or less, and more preferably 0.3 mm or more and 1.5 mm or less, which suppresses warping of the decorative sheet 10 and allows the above-mentioned effects to be more pronounced.

[0094] The decorative sheet 10 may have an adhesive layer (not shown) provided on the back surface of the core material layer 11. This adhesive layer improves work efficiency when attaching the decorative sheet 10 to an interior material.

[0095] Furthermore, when the flammability of the decorative sheet 10 during alcohol combustion is determined in accordance with the railway vehicle material combustion test prescribed by the Ministerial Ordinance of the Ministry of Land, Infrastructure, Transport and Tourism, it is preferable that the decorative sheet 10 be in the non-flammable judgment standard category. The non-flammable judgment standard category requires that there is no ignition or flame during alcohol combustion and that there is minimal smoke generation.

[0096] Furthermore, when the decorative sheet 10 is judged for flammability after alcohol combustion in accordance with the above-mentioned railway vehicle material flammability test, it is preferable that the decorative sheet 10 be in the non-flammable judgment standard category. The non-flammable judgment standard category requires that discoloration due to carbonization be 100 mm or less and that surface deformation be 100 mm or less.

[0097] A decorative sheet 10 that has been judged to be non-flammable as described above has sufficiently low flammability, and is therefore particularly useful as a material for railway vehicles, for example.

[0098] Furthermore, when the decorative sheet 10 is evaluated for flame resistance in accordance with the cone calorimeter test specified in ISO 5660-1:2002, it is determined to be in the non-flammable category, i.e., the total calorific value is 8 MJ / m 2 or less, and the maximum heat generation rate is 300kW / m 2 It is preferable that:

[0099] A decorative sheet 10 that satisfies the total heat release amount and maximum heat release rate as described above has excellent flame resistance, and is therefore particularly useful as a material for railway vehicles, for example.

[0100] The decorative sheet 10 is subjected to the railway vehicle material combustion test and the cone calorimeter test in the form of a third test piece prepared by the method described below.

[0101] First, a pressure-sensitive adhesive acrylic adhesive tape is laminated onto the decorative sheet 10 at a roll linear pressure of 40 N / cm to obtain a decorative sheet with an adhesive backing. This decorative sheet with an adhesive backing is then sequentially bonded to a 1.6 mm thick metal-based melamine resin decorative board, commonly used as an interior material for vehicles, using a metal hand roll while degassing from one side. The resulting sheet is then cut to the required size to obtain a third test piece. The metal-based melamine resin decorative board is a decorative board with a 1.2 mm thick aluminum plate.

[0102] The overall average thickness of the decorative sheet 10 is preferably 0.1 mm or more and 0.6 mm or less, and more preferably 0.2 mm or more and 0.5 mm or less. By setting the overall average thickness of the decorative sheet 10 within this range, it is possible to impart excellent strength to the decorative sheet 10 while performing outward bending with a small bending radius. Specifically, the decorative sheet 10 can be bent at room temperature (usually about 20 to 30°C) with a minimum bending radius R of 15 mmR or less. Furthermore, it can achieve the thinness and weight reduction required for renewal materials that are attached to interior materials that have been found to have deteriorated.

[0103] The minimum bending radius R refers to the smallest mold radius R that will not cause defects such as cracks in the decorative sheet 10 and will produce 100% good products, even if repeated room temperature bending processing is performed in one direction along a mold having a curved portion of radius R.

[0104] (Method of manufacturing decorative sheet 10) The decorative sheet 10 having the above-described configuration can be obtained by preparing the surface layer 12 and core layer 11 having the above-described configuration, stacking them together, and then heating and press-molding the resulting laminate.

[0105] The conditions for obtaining the decorative sheet 10 by hot and pressure molding are not particularly limited, but for example, it is preferable that the temperature be 120°C or higher and 140°C or lower, the pressure be 2MPa or higher and 8MPa or lower, and the time be 3 minutes or higher and 60 minutes or lower.

[0106] Furthermore, during the heat and pressure molding of the decorative sheet 10, this surface can be given a mirror finish by overlaying a mirror-finished plate on the surface of the surface layer 12 opposite the core layer 11. Furthermore, this surface can be given an embossed finish by overlaying an embossed plate or embossed film or the like. The decorative sheet 10 can be produced by the above-described heat and pressure molding.

[0107] The decorative sheet of the present invention has been described above, but the present invention is not limited to this, and each part that makes up the decorative sheet can be replaced with any other configuration that can perform the same function.

[0108] Furthermore, the decorative sheet of the present invention may have any optional components added thereto in addition to the above-mentioned components.

[0109] More specifically, for example, the decorative sheet of the present invention may be provided with an adhesive layer laminated on the surface of the core material layer opposite the surface layer, for attachment to interior materials that have been found to have deteriorated. [Example]

[0110] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples in any way.

[0111] 1. Manufacturing of decorative sheet 10 Example 1 First, decorative paper containing titanium oxide was prepared as a support substrate. A varnish containing a diallyl phthalate resin and an unsaturated polyester resin was prepared as a resin composition. The blending ratios of the resins are shown in Table 1.

[0112] Next, the varnish was applied to one side of the support substrate and dried in a hot air dryer at 120° C. for 90 seconds to obtain a surface layer forming material.

[0113] Next, aluminum foil was overlaid on the obtained surface layer-forming material and heated and pressurized for 20 minutes at a temperature of 140°C and a pressure of 8 MPa to obtain decorative sheet 10 of Example 1 having an average thickness of 0.4 mm. The aluminum foil used had a thickness of 0.3 mm and its surface was treated with a primer using an epoxy resin.

[0114] (Examples 2 to 8 and Comparative Example) The decorative sheets 10 of Examples 2 to 8 and the comparative example were obtained in the same manner as in Example 1, except that the construction of the decorative sheet 10 was changed as shown in Table 1.

[0115] 2. Evaluation The decorative sheets 10 of the examples and comparative examples were evaluated by the following methods.

[0116] 2.1. Measurement of the magnitude of the displacement X occurring in the decorative sheet 10 (Requirement A) The magnitude of the displacement amount X was measured for the decorative sheets 10 of the examples and comparative examples using the method described above as requirement A.

[0117] 2.2. Measurement of the ratio of dimensional change occurring in the surface layer 12 of the decorative sheet 10 (Requirement B) For the decorative sheets 10 of the examples and comparative examples, the total dimensional change rate was calculated using the method described above as requirement B.

[0118] 2.3. Evaluation of Adhesion of Decorative Sheet 10 to Interior Materials The decorative sheets 10 of each example and comparative example were attached to interior materials using double-sided tape. The ease of application of the decorative sheets 10 was evaluated in accordance with the following evaluation criteria. Note that the ease of application mainly refers to the length of time required for application.

[0119] ○: The decorative sheet has good application properties. ×: The decorative sheet is poorly applied.

[0120] 2.4. Evaluation of Appearance After Application of Decorative Sheet 10 The decorative sheets 10 of each example and comparative example were attached to interior materials using double-sided tape. The appearance of the decorative sheets 10 after attachment was then observed, and the observation results were evaluated in accordance with the following evaluation criteria. The evaluation of appearance mainly focused on peeling of the edges due to warping of the decorative sheet 10, ducts (waving or undulation), etc.

[0121] ○: The appearance of the decorative sheet after application is good ×: The appearance of the decorative sheet after application is poor.

[0122] 2.5. Evaluation of processability of decorative sheet 10 For each of the decorative sheets 10 of the Examples and Comparative Examples, bending and straightening were repeated 10 times at room temperature with a minimum bending radius of 10 mm. The appearance of the bent area was then visually inspected, and the results were evaluated according to the following criteria. The evaluation of appearance primarily focused on whether defects such as cracks had occurred in the bent area.

[0123] ○: The appearance of the processed part is good ×: The appearance of the processed part is poor.

[0124] 2.6. Evaluation of Stain Resistance of Decorative Sheet 10 For each of the decorative sheets 10 of the Examples and Comparative Examples, a staining material was dropped onto the surface layer, the sheet was covered with a lid, and the sheet was left for 24 hours, after which it was washed with water and ethanol. The presence or absence of staining was then visually observed, and the observation results were evaluated according to the following evaluation criteria. The staining material used was blue-black office ink. The appearance evaluation primarily focused on the presence or absence of discoloration at the location where the staining material was dropped.

[0125] ○: The appearance of the area where the contaminating material was dropped is good. ×: The appearance of the area where the contaminating material was dropped was poor.

[0126] 2.7. Evaluation of the Weight of the Decorative Sheet 10 The decorative sheets 10 of the examples and comparative examples were each evaluated for weight based on specific gravity. The evaluation criteria were as follows:

[0127] ○: Relatively small specific gravity ×: Relatively large specific gravity

[0128] 2.8. Cost Evaluation of Decorative Sheet 10 The decorative sheets 10 of the examples and comparative examples were each evaluated for cost. The evaluation criteria were as follows:

[0129] ○: Relatively low cost ×: Relatively high cost

[0130] 2.9. Evaluation of Flammability of Decorative Sheet 10 The decorative sheets 10 of the examples and comparative examples were evaluated for flammability in the railway vehicle material flammability test and the cone calorimeter test using the methods described above. The results were then evaluated in accordance with the following evaluation criteria.

[0131] 〇: Meets the criteria for "non-flammable" in both the railway vehicle material combustion test and the cone calorimeter test △: The material is classified as "non-flammable" in only the railway vehicle material combustion test or only the cone calorimeter test. ×: Neither of them meets the criteria for "non-flammable" The evaluation results are shown in Table 1.

[0132] [Table 1]

[0133] As shown in Table 1, in each example, the decorative sheet satisfied requirement A. The decorative sheets of each example were found to meet the non-flammability standards when applied to interior materials. Furthermore, the decorative sheets of each example were found to have good appearance and application properties, as warping was sufficiently suppressed or prevented. [Explanation of symbols]

[0134] 10 Decorative Sheet 11 Core layer 12 Surface layer 20 Fixture 30 flat surface 100 First test piece 101 Short side 102 short side C1 Warpage C2 Warpage RP reference point X displacement

Claims

1. A decorative sheet comprising a laminate having a core layer having heat dissipation properties and a surface layer laminated on one side of the core layer, the surface opposite to the core layer forming a design surface, the surface layer is composed of a resin composition containing a thermosetting resin and a support substrate that supports the resin composition by being impregnated therewith; A decorative sheet characterized by satisfying the following requirement A. Requirement A: The displacement measured by the following procedures (A-1) to (A-6) is 7.0 mm or less. (A-1) The decorative sheet is used as a first test piece in the shape of a strip with a short side of 20 mm and a long side of 120 mm. (A-2) The first test piece is clamped and fixed in a range of 20 mm from the other short side with a fixing jig so that one of the short sides of the first test piece is floating in the air. (A-3) The first test piece fixed to the fixing jig is left standing in an environment of a temperature of 40°C and a relative humidity of 93% for 96 hours. (A-4) The first test piece fixed to the fixing jig is placed on a flat surface, and the vertical position of one of the short sides is set as a reference point. (A-5) The first test piece fixed to the fixing jig is left standing in an environment of a temperature of 70°C and a relative humidity of 10% for 24 hours. (A-6) The amount of displacement of one of the short sides in the vertical direction from the reference point is defined as the amount of displacement.

2. 2. The decorative sheet according to claim 1, wherein the surface layer satisfies the following requirement B: Requirement B: Six second test pieces, each 140 mm long and 13 mm wide, are prepared from the surface layer. In accordance with Method B for dimensional stability (high temperature), a test method for thermosetting resin high-pressure decorative panels specified in JIS K 6902:2022, three of the second test pieces are subjected to a low-humidity test in which they are left standing in a thermostatic chamber at 70°C for 24 hours, and the remaining three second test pieces are subjected to a high-humidity test in which they are left standing in a thermostatic chamber at 40°C and a relative humidity of 93% for 96 hours. After this, when the total dimensional change rate is calculated as the sum of the average longitudinal dimensional change rate of the second test pieces in the low-humidity test and the average longitudinal dimensional change rate of the second test pieces in the high-humidity test, the absolute value of the total dimensional change rate is 1.0% or less.

3. 3. The decorative sheet according to claim 2, wherein said resin composition contains a diallyl phthalate resin and an unsaturated polyester resin as said thermosetting resin.

4. 4. The decorative sheet according to claim 3, wherein the content of said diallyl phthalate resin in said resin composition is 20% by weight or more and 90% by weight or less.

5. The support substrate is porous and has a basis weight of 40 g / m ２ 150g / m or more ２ The decorative sheet according to claim 4, wherein:

6. 6. The decorative sheet according to claim 5, wherein the surface layer has an average thickness of 0.05 mm or more and 0.30 mm or less.

7. 2. The decorative sheet according to claim 1, wherein said core layer is mainly made of a heat-dissipating material having a thermal conductivity of 10 W / m·K or more.

8. 8. The decorative sheet according to claim 7, wherein the heat-dissipating material is a metallic material.

9. 9. The decorative sheet according to claim 8, wherein at least the surface of the core layer on the side of the surface layer is treated with a primer using an epoxy resin.

10. 10. The decorative sheet according to claim 9, wherein the core layer has an average thickness of 0.20 mm or more and 0.50 mm or less.

11. 2. The decorative sheet according to claim 1, wherein the decorative sheet is attached to the surface of an interior material of a vehicle.

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