Decorative sheet and method for manufacturing the same

Abstract

The objective is to provide a decorative sheet that combines processability in three-dimensional molding, adhesion to the substrate, and scratch resistance on the surface. [Solution] A method for manufacturing a three-dimensionally moldable decorative sheet having at least a resin base layer and a surface protective layer, characterized in that a resin composition containing a specific ultraviolet-curable resin (A) and a specific thermosetting resin (B) in a mass ratio of 30:70 to 60:40 is applied to the surface of a long sheet forming the resin base layer, the ultraviolet-curable resin (A) is cured by ultraviolet irradiation and wound into a roll, and then cured at 35 to 55°C to completely cure the thermosetting resin (B) and form a surface protective layer.

Description

Technical Field

[0001] The present invention relates to a decorative sheet and a method for manufacturing the same.

Background Art

[0002] For example, as interior and exterior members used in building materials, it is widely practiced to attach a decorative sheet to the surface of a three-dimensional substrate to impart design properties. As a decorative sheet, for example, a substrate, a colored ink layer, a primer layer, and a surface protective layer are provided in this order, the substrate is a biaxially stretched polyester film of 20 μm or more and 95 μm or less, and the surface protective layer is a cured product of a resin composition containing an ionizing radiation curable resin and a thermosetting resin in a mass ratio of 95:5 to 50:50. A decorative sheet has been proposed (Patent Document 1). Since this biaxially stretched polyester film is oriented and crystallized in the biaxial direction, there is no film elongation around 100 ° C and three-dimensional molding is impossible.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the prior art such as Patent Document 1, it is difficult to obtain a decorative sheet that兼备 all of the processability in three-dimensional molding, adhesion to a substrate, and scratch resistance of the surface. The main object of the present invention is to provide a decorative sheet and a method for manufacturing the same that兼备 all of the processability in three-dimensional molding, adhesion to a substrate, and scratch resistance of the surface.

Means for Solving the Problems

[0005] It should be noted that the description "兼备 all of the processability in three-dimensional molding, adhesion to a substrate, and scratch resistance of the surface" in the translation contains an inappropriate Chinese character "兼备" which may not be recognized in English. It is recommended to use appropriate English expressions such as "have all of the... properties" to accurately convey the meaning. The above translation is presented as is based on the requirements, but this part can be further optimized for better readability and accuracy.The present invention includes the following configuration. [1]: A three-dimensionally moldable decorative sheet having at least a resin substrate layer and a surface protective layer, The aforementioned surface protective layer consists of a cured product of a resin composition containing an ultraviolet-curing resin (A) and a thermosetting resin (B) in a mass ratio of 30:70 to 60:40. The UV-curable resin (A) is one or more urethane (meth)acrylates selected from polyester, polyether, and polycarbonate types, having 2 to 3 functional groups, and the pencil hardness of the cured product is from HB to 4B. The thermosetting resin (B) is a decorative sheet comprising an acrylic polyol resin and a polyisocyanate compound as a curing agent. [2] The resin substrate layer is made of a polyester sheet or a polypropylene sheet having a tensile elongation of 200% or more at 90°C and a load of 4.0 to 9.0 N / cm in the range of 50% to 200% of the tensile elongation. The decorative sheet according to [1], wherein the thickness of the resin substrate layer is 120 to 250 μm. [3] The polyester sheet having a tensile elongation of 200% or more at 90°C is an amorphous polyester sheet, as described in [2]. [4] The decorative sheet according to [2], wherein the polypropylene sheet having a tensile elongation of 200% or more at 90°C is an amorphous polypropylene sheet containing an olefin elastomer and polyethylene resin. [5]: The decorative sheet according to any one of [1] to [4], wherein the resin base layer is a 2-type 3-layer or 3-type 3-layer structure using recycled polyethylene terephthalate resin or recycled polypropylene resin as an intermediate layer. [6]: A method for manufacturing a three-dimensionally moldable decorative sheet having at least a resin substrate layer and a surface protective layer, A method for manufacturing a decorative sheet, characterized by applying a resin composition containing the following UV-curing resin (A) and thermosetting resin (B) in a mass ratio of 30:70 to 60:40 to the surface of a long sheet forming the resin substrate layer, curing the UV-curing resin (A) by UV irradiation and winding it into a roll, and then curing it at 35 to 55°C to completely cure the thermosetting resin (B) and form a surface protective layer. UV-curing resin (A): A UV-curing resin comprising one or more urethane (meth)acrylates selected from polyester, polyether, and polycarbonate types, having 2 to 3 functional groups, and having a pencil hardness of HB to 4B for the cured product. Thermosetting resin (B): A thermosetting resin consisting of an acrylic polyol resin and a polyisocyanate compound as a curing agent. [7]: The resin substrate layer is made of a polyester sheet or a polypropylene sheet having a tensile elongation of 200% or more at 90°C and a load of 4.0 to 9.0 N / cm in the range of 50% to 200% of the tensile elongation. The method for manufacturing a decorative sheet according to [6], wherein the thickness of the resin substrate layer is 120 to 250 μm. [8] The method for manufacturing a decorative sheet according to [7], wherein the polyester sheet having a tensile elongation of 200% or more at 90°C is an amorphous polyester sheet. [9] The method for manufacturing a decorative sheet according to [7], wherein the polypropylene sheet having a tensile elongation of 200% or more at 90°C is an amorphous polypropylene sheet containing an olefin elastomer and a polyethylene resin.

[10] : A method for manufacturing a decorative sheet according to any one of [6] to [9], wherein the resin base layer is a 2-type 3-layer or 3-type 3-layer structure using recycled polyethylene terephthalate resin or recycled polypropylene resin as an intermediate layer. [Effects of the Invention]

[0006] The present invention provides a decorative sheet and a method for manufacturing the same that combine processability in three-dimensional molding, adhesion to a substrate, and surface scratch resistance. In particular, a decorative sheet using recycled resin having the above-mentioned properties can also be provided. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic cross-sectional view showing a decorative sheet according to one embodiment. [Modes for carrying out the invention]

[0008] In this specification, the following terms have the meanings set forth below. "(Meth)acrylic" means acrylic or methacrylic. "(meth)acryloyl group" means either an acryloyl group or a methacryloyl group. "(Meth)acrylate" means acrylate or methacrylate. The "~" symbol indicating a numerical range means that the numbers before and after it are included as the lower and upper limits, respectively.

[0009] The decorative sheet of the present invention will be described below with reference to the drawings, showing an example. Note that the dimensions and other specifications shown in the following description are examples only, and the present invention is not necessarily limited to them. It can be modified as appropriate without altering its essence.

[0010] [Decorative sheet] The decorative sheet according to the embodiment is a three-dimensionally moldable decorative sheet having at least a resin substrate layer and a surface protective layer, wherein the surface protective layer consists of a cured product of a resin composition containing a UV-curing resin (A) and a thermosetting resin (B) in a mass ratio of 30:70 to 60:40.

[0011] Figure 1 is a schematic cross-sectional view showing a decorative sheet according to one embodiment. As shown in FIG. 1, a cosmetic sheet 10 according to an example of an embodiment includes a resin base material layer 12 and a surface protection layer 14 provided on the resin base material layer 12. In addition, the cosmetic sheet according to the embodiment may have one or more other layers other than the resin base material layer and the surface protection layer on any one or more of the opposite side of the resin base material layer 12 from the surface protection layer 14, between the resin base material layer 12 and the surface protection layer 14, and the opposite side of the surface protection layer 14 from the resin base material layer 12.

[0012] (Resin base material layer) A resin sheet can be used for the resin base material layer. The resin sheet may be a single layer or a multi-layer. In the case of a multi-layer, for example, it can be two types and two layers, or two types and three layers. In the case of a multi-layer, by making the layer other than the surface layer a resin layer mainly composed of recycled resin, resources can be effectively utilized.

[0013] As the resin sheet, a polyester-based sheet or a polypropylene-based sheet is preferable. The polyester resin used for the polyester-based sheet may be a homopolymer or a copolymer. Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. As the polyester resin constituting the polyester-based sheet, one type may be used alone, or two or more types may be used in combination.

[0014] For the polyester-based sheet, in order to improve the processability, a modified polyester (PETG) obtained by copolymerizing ethylene glycol and cyclohexanedimethanol with terephthalic acid may be blended. Also, the polyester-based sheet may be processed as an amorphous sheet to improve the processability. For the polypropylene-based sheet, at least one of an olefin-based elastomer and a polyethylene-based resin may be blended in order to improve the processability.

[0015] When a resin sheet sample with a thickness of 200 μm and a width of 10 mm is subjected to a tensile test at a temperature of 90°C and a tensile speed of 500 mm / min, it is preferable that the tensile elongation is 200% or more. Furthermore, the load measured in the tensile test when the tensile elongation is in the range of 50% to 200% is preferably 4.0 to 9.0 N / cm, more preferably 4.5 to 8.5 N / cm. If the load is within the above range, the processability for three-dimensional molding such as vacuum forming, pressure forming, and membrane press molding will be improved. Also, if the load is below the upper limit, it is easier to suppress the increase in processing pressure for three-dimensional molding. If the load is above the lower limit, it is easier to suppress the occurrence of wrinkles during molding due to excessive stretching of the decorative sheet.

[0016] As a polyester sheet with a tensile elongation of 200% or more at 90°C, an amorphous polyester sheet is preferred. The amorphous polyester sheet is obtained by rapidly cooling the sheet coming out of the T-die in extrusion molding using two cooling rolls at 20°C or below, thereby significantly reducing the degree of crystallinity.

[0017] As a polypropylene sheet with a tensile elongation of 200% or more at 90°C, an amorphous polypropylene sheet containing an olefin-based elastomer and polyethylene resin is preferred. Examples of olefin-based elastomers include ethylene-α-olefin random copolymer, propylene-α-olefin random copolymer, and butene-1-α-olefin random copolymer, with a density of 0.91 g / cm³. 3 Preferably, 0.90 g / cm³ 3 Examples include the following: α-olefins include 1-hexene and 1-octene. Commercially available olefin-based elastomers such as those manufactured by Mitsui Chemicals, Nippon Polyethylene Co., Ltd., and Dow Chemical can be used.

[0018] It is preferable to use a polyethylene terephthalate-based sheet made from recycled polyethylene terephthalate resin (hereinafter referred to as "recycled PET") for the resin substrate layer. Typically, recycled PET exhibits discoloration and the presence of foreign matter. Therefore, when using recycled PET, it is preferable to use a three-layer colored sheet in which recycled PET is used as the intermediate layer of the resin substrate layer, and unused polyethylene terephthalate (PET) resin is used for both outer layers. This ensures color stability while effectively utilizing recycled PET. As a resin substrate layer using recycled PET, a layer consisting of two types of three layers or three types of three layers with recycled PET as the intermediate layer is preferred.

[0019] Polyester sheets using recycled PET are preferably amorphous polyester sheets. For example, by using recycled PET as the intermediate layer material, and extruding a sheet from a T-die capable of forming a 2-type 3-layer or 3-type 3-layer sheet, and then rapidly cooling the sheet between two cooling rolls at 20°C or below to significantly reduce the degree of crystallinity, an amorphous polyester sheet using recycled PET as the intermediate layer can be obtained.

[0020] It is also preferable to use a polypropylene-based sheet made from recycled polypropylene resin (hereinafter referred to as "recycled PP") for the resin substrate layer. Typically, recycled PP (polypropylene) also contains coloring and foreign matter. Therefore, when using recycled PP, it is preferable to use a three-layer colored sheet in which recycled PP is used as the intermediate layer of the resin base layer, and unused polypropylene (PP) resin is used for both outer layers. This ensures color stability while effectively utilizing recycled PP. As a resin substrate layer using recycled PP, a layer consisting of two types of three layers or three types of three layers with recycled PP as the intermediate layer is preferred.

[0021] Polypropylene sheets using recycled PP are preferably amorphous polypropylene sheets. For example, by blending an olefin elastomer and polyethylene resin with the recycled PP used as the intermediate layer to significantly reduce the degree of crystallinity, an amorphous polypropylene sheet using recycled PP as the intermediate layer can be obtained.

[0022] The thickness of the resin substrate layer is preferably 150 to 300 μm, more preferably 180 to 250 μm. If the thickness of the resin substrate layer is greater than or equal to the lower limit, the decorative sheet is more stretchable, making three-dimensional molding easier. If the thickness of the resin substrate layer is less than or equal to the upper limit, the decorative sheet exhibits excellent moldability. The thickness of the resin substrate layer is the average of the thicknesses measured at any three locations on the resin substrate.

[0023] The resin sheet constituting the resin substrate layer 12 may contain a coloring agent. Furthermore, the resin sheet may contain additives such as fillers, flame retardants, antioxidants, lubricants, UV absorbers, and light stabilizers, as needed. These additives may be used individually or in combination of two or more.

[0024] A pattern may be provided on the surface of the resin substrate layer 12 on the side where the surface protection layer 14 is provided. The pattern can be applied by gravure printing, inkjet printing, or the like. The pattern is not particularly limited and examples include wood grain patterns, stone patterns, sand patterns, tile patterns, brick patterns, fabric patterns, leather patterns, geometric figures, and abstract patterns.

[0025] The surface of the resin substrate layer 12 on the side where the surface protection layer 14 is provided may be subjected to surface treatment by oxidation or an easy-adhesion coating treatment in order to improve the adhesion between the resin substrate layer 12 and the surface protection layer 14. Examples of surface treatments using oxidation methods include corona discharge treatment and ozone / ultraviolet treatment. Examples of resins used in easy-adhesion coating treatments include polyester resins, acrylic resins, and urethane resins. These resins may be used individually or in combination of two or more types.

[0026] (Surface protective layer) The surface protective layer 14 is a layer made of a cured product of a resin composition containing an ultraviolet-curing resin (A) and a thermosetting resin (B) in a mass ratio of 30:70 to 60:40.

[0027] UV-curable resin (A) is a resin that hardens by crosslinking when irradiated with ultraviolet light. UV-curable resin (A) is one or more urethane (meth)acrylates selected from polyester-based urethane (meth)acrylates, polyether-based urethane (meth)acrylates, and polycarbonate-based urethane (meth)acrylates, having 2 to 3 functional groups. The pencil hardness of the cured product of UV-curable resin (A) ranges from HB to 4B.

[0028] A functional group possessed by the UV-curable resin (A) is the (meth)acryloyl group. The UV-curable resin (A) has two or three (meth)acryloyl groups. The UV-curing resin (A) may be an oligomer or a prepolymer. UV-curable resin (A) can be obtained, for example, by esterifying a polyurethane oligomer, which is obtained by the reaction of a polyether polyol, polyester polyol, or polycarbonate polyol with a polyisocyanate, with (meth)acrylic acid. As the UV-curing resin (A), one type may be used alone, or two or more types may be used in combination.

[0029] The pencil hardness of the cured product of UV-curable resin (A) is between HB and 4B, preferably between HB and 2B. If the pencil hardness of the cured product of UV-curable resin (A) is within the above range, it will have excellent processability for three-dimensional molding such as vacuum forming and membrane press molding. The pencil hardness is measured according to JIS K 5600-5-4:1999.

[0030] When curing with ultraviolet light, a photopolymerization initiator may be used for the ultraviolet-curable resin (A). The photopolymerization initiator can be appropriately selected from those conventionally used, and preferred examples include benzoin-based photopolymerization initiators, acetophenone-based photopolymerization initiators, phenyl ketone-based photopolymerization initiators, benzophenone-based photopolymerization initiators, and anthraquinone-based photopolymerization initiators. The amount of photopolymerization initiator used is preferably 0.1 to 5 parts by mass per 100 parts by mass of ultraviolet curing resin (A).

[0031] Thermosetting resin (B) is a resin that is crosslinked and hardened by heating. Preferably, thermosetting resin (B) consists of an acrylic polyol resin and a curing agent. Examples of acrylic polyol resins include acrylic polyols having two or more hydroxyl groups in their molecules. Acrylic polyol resins can be obtained, for example, by copolymerizing a (meth)acrylic acid ester with a hydroxyl group-containing (meth)acrylic acid ester.

[0032] Examples of (meth)acrylic acid esters used in acrylic polyol resins include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and octyl (meth)acrylate. These (meth)acrylic acid esters may be used individually or in combination of two or more.

[0033] Examples of hydroxyl group-containing (meth)acrylic acid esters used in acrylic polyol resins include 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate. These hydroxyl group-containing (meth)acrylic acid esters may be used individually or in combination of two or more.

[0034] The weight-average molecular weight of the acrylic polyol resin is preferably 20,000 to 200,000, more preferably 25,000 to 150,000, and even more preferably 30,000 to 100,000. If the weight-average molecular weight of the acrylic polyol resin is above the lower limit, it exhibits excellent drying properties. If the weight-average molecular weight of the acrylic polyol resin is below the upper limit, it is easier to obtain sufficient processability. The weight-average molecular weight of acrylic polyol resins is a value equivalent to standard polystyrene, measured by gel permeation chromatography (GPC).

[0035] The glass transition temperature (Tg) of the acrylic polyol resin is preferably 65 to 110°C, more preferably 75 to 105°C. If the Tg of the acrylic polyol resin is above the lower limit, it exhibits excellent drying properties and heat resistance. If the Tg of the acrylic polyol resin is below the upper limit, it exhibits excellent drying properties and is likely to maintain sufficient hardness. For acrylic polyol resins, the Tg value used is the midpoint between the extrapolation glass transition onset temperature and the extrapolation glass transition end temperature, measured using a differential scanning calorimeter.

[0036] The hydroxyl value of the acrylic polyol resin is preferably 5 to 30 mmHg / KOH, more preferably 10 to 25 mmHg / KOH. If the hydroxyl value of the acrylic polyol resin is above the lower limit, it exhibits excellent drying properties. If the hydroxyl value of the acrylic polyol resin is below the upper limit, it is easier to suppress the occurrence of blocking. The hydroxyl value of acrylic polyol resins is expressed in milligrams as the amount of potassium hydroxide equivalent to the number of hydroxyl groups per gram of sample, and is a value measured based on the potentiometric titration method specified in JIS K 0070:1992.

[0037] Polyisocyanate compounds are preferred as curing agents for thermosetting resin (B). Polyisocyanate compounds are compounds having two or more isocyanate groups in their molecule. Examples of polyisocyanate compounds include aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate; and aromatic ring-containing polyisocyanates such as tolylene diisocyanate, xylylene diisocyanate, and diphenylmethane diisocyanate. These polyisocyanate compounds may be used individually or in combination of two or more.

[0038] The mass ratio of the UV-curing resin (A) to the thermosetting resin (B) is 30:70 to 60:40, preferably 30:70 to 50:50, and more preferably 35:65 to 48:52. If the ratio of thermosetting resin (B) is above the lower limit, the processability for three-dimensional molding such as vacuum forming and membrane press molding will be excellent. If the ratio of thermosetting resin (B) is below the upper limit, scratch resistance will be improved.

[0039] The resin composition forming the surface protective layer may also contain resins other than the ultraviolet-curing resin (A) and the thermosetting resin (B). Other resins are not particularly limited, and examples include polysyl polyol resins. These other resins may be used individually or in combination of two or more.

[0040] The surface protective layer may contain various additives depending on the required physical properties. Examples of additives include UV absorbers, light stabilizers, wear resistance enhancers, antistatic agents, leveling agents, coupling agents, fillers, and solvents.

[0041] Either an inorganic or organic UV absorber may be used as the UV absorber. As inorganic UV absorbers, titanium dioxide, cerium oxide, and zinc oxide with an average particle size of about 5 to 120 nm can be preferably used. As organic UV absorbers, for example, benzotriazole-based UV absorbers, triazine-based UV absorbers, and benzophenone-based UV absorbers are preferred. Among UV absorbers, triazine-based absorbers are preferred because they have high UV absorption capacity and do not degrade easily even when exposed to high energy such as ultraviolet light. Examples of triazine-based UV absorbers include BASF's product names "TINUVIN 479," "TINUVIN 400," "TINUVIN 405," and "TINUVIN 460."

[0042] If the surface protective layer contains an ultraviolet absorber, the amount of ultraviolet absorber is preferably 0.5 to 10 parts by mass, more preferably 1 to 5 parts by mass, per 100 parts by mass of the resin forming the surface protective layer. If the surface protective layer contains a light stabilizer, the amount of the light stabilizer is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the resin forming the surface protective layer.

[0043] The thickness of the surface protective layer is preferably 5 to 20 μm, more preferably 6 to 12 μm. If the thickness of the surface protective layer is greater than or equal to the lower limit, the scratch resistance is excellent. If the thickness of the surface protective layer is less than or equal to the upper limit, the hardness is easily maintained and the decrease in scratch resistance is easily suppressed. The thickness of the surface protection layer is the average of the thicknesses measured at any three locations within the surface protection layer.

[0044] The applications of the decorative sheet according to this embodiment are not particularly limited, and examples include surface materials for doors, furniture, etc. The decorative sheet according to this embodiment is suitable for imparting design to a substrate having a three-dimensional shape by three-dimensional molding such as vacuum forming or membrane press molding.

[0045] [Manufacturing method for decorative sheets] The decorative sheets mentioned above can be manufactured, for example, by the method described below. The method for manufacturing a decorative sheet according to the embodiment is a method for manufacturing a three-dimensionally moldable decorative sheet having at least the resin base layer and surface protective layer described above. In a method for manufacturing a decorative sheet according to one embodiment, a resin composition containing an ultraviolet-curing resin (A) and a thermosetting resin (B) in a mass ratio of 30:70 to 60:40 is applied to the surface of a long sheet forming the resin substrate layer. The ultraviolet-curing resin (A) is cured by ultraviolet irradiation and wound into a roll, and then cured at 35 to 55°C to completely cure the thermosetting resin (B) and form a surface protective layer.

[0046] As the long sheet, a long piece of the resin sheet described above can be used. When forming a surface protective layer consisting of a resin composition containing an ultraviolet-curing resin (A) and a thermosetting resin (B), for example, the ultraviolet-curing resin (A) and the thermosetting resin (B) are mixed in a predetermined ratio, a solvent is added to adjust the viscosity, and various additives are added as needed to prepare the coating agent. The viscosity of the coating agent is not particularly limited, as long as it is a viscosity that allows for application. Preferred solvents include ethyl acetate, butyl acetate, and methyl ethyl ketone, but are not limited to these.

[0047] The solid resin content of the coating agent is preferably 30 to 70% by mass, more preferably 35 to 55% by mass. If the proportion of solid resin content is above the lower limit, it can be easily applied to the resin substrate layer to form a surface protective layer. If the proportion of solid resin content is above the lower limit, the amount of solvent used can be reduced and the drying time can be shortened.

[0048] For example, a surface protective layer can be formed by applying a coating agent to a resin substrate layer such that the thickness after curing is 5 to 20 μm to form an uncured resin composition layer, curing the UV-curable resin (A) by irradiating it with ultraviolet light, and curing the thermosetting resin (B) by heating. As for the method of applying the coating agent, known methods such as gravure coating, bar coating, and reverse coating can be used, and gravure coating is preferred.

[0049] The wavelength of ultraviolet light used to cure the UV-curable resin (A) is preferably 254 to 436 nm, more preferably 300 to 365 nm. A high-pressure mercury lamp, for example, can be used as the light source. The cumulative amount of UV light irradiated when curing UV-curable resin (A) is preferably 100 to 500 mJ / cm². 2 More preferably 300-400 mJ / cm² 2 That is the case.

[0050] When curing the thermosetting resin (B) at 35-55°C, it is preferable to do so in a constant temperature chamber. The heating temperature for curing the thermosetting resin (B) is preferably 35 to 55°C, more preferably 40 to 53°C. If the heating temperature exceeds 55°C, the long sheet forming the resin substrate layer softens, and shrinkage due to residual stress during extrusion molding causes undesirable curling. Conversely, if the heating temperature falls below 35°C, curing takes too long, which is also undesirable. The heating time for curing the thermosetting resin (B) varies depending on the heating temperature, but is preferably 2 to 10 days, more preferably 5 to 7 days. For the curing conditions of the thermosetting resin (B), for example, curing can be performed for 5 days at 40°C or 3 days at 50°C.

[0051] The method for manufacturing the decorative sheet according to the embodiment is not limited to the method described above. For example, regarding the timing of curing the UV-curable resin (A) by UV irradiation and the thermosetting resin (B) by heating, it is preferable to cure the UV-curable resin (A) first and then the thermosetting resin (B), but it is also possible to cure the UV-curable resin (A) after curing the thermosetting resin (B), or to cure the UV-curable resin (A) and the thermosetting resin (B) simultaneously.

[0052] As described above, in the present invention, by forming a surface protective layer on a resin substrate layer using a cured product of a resin composition containing a specific ultraviolet-curable resin (A) and a thermosetting resin (B) in a specific ratio, a decorative sheet can be made that possesses processability in three-dimensional molding, adhesion to the substrate, and scratch resistance on the surface. [Examples]

[0053] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following description.

[0054] [material] The materials used in this embodiment are shown below. (Ultraviolet curing resin (A)) A-1: Polyester-based urethane (meth)acrylate, number of functional groups: 3, pencil hardness of cured product: 2B A-2: Polyether-based urethane (meth)acrylate, number of functional groups: 2, pencil hardness of cured product: B A-3: Polycarbonate-based urethane (meth)acrylate, number of functional groups: 2, pencil hardness of cured product: 3B

[0055] (Other UV-curing resins (X)) X-1: Polyester-based urethane (meth)acrylate, Number of functional groups: 7, Pencil hardness of cured product: 2H X-2: Polyester-based urethane (meth)acrylate, number of functional groups: 6, pencil hardness of cured product: 3H X-3: Polycaprolactam-based urethane (meth)acrylate, number of functional groups: 2, pencil hardness: B

[0056] (Curable resin (B)) B-1: A mixture of acrylic polyol (Tg: 100℃, hydroxyl value: 15 mmHg / KOH, solid resin content: 38% by mass, weight-average molecular weight: 55,000) and a curing agent (hexamethylene diisocyanate) in a mass ratio of 5:1. B-2: A mixture of acrylic polyol (Tg: 93℃, hydroxyl value: 10 mmHg / KOH, solid resin content: 38% by mass, weight-average molecular weight: 75,000) and a curing agent (hexamethylene diisocyanate) in a mass ratio of 6:1.

[0057] (Other ingredients) Photopolymerization initiator: "OmniRat 184" manufactured by IGM Resins BV. UV absorber: "Chinubin 400" manufactured by BASF.

[0058] [Manufacturing Example 1] 60% recycled PP by mass, 5% unused PP resin by mass, olefin-based elastomer (ethylene-α-olefin random copolymer, Mitsui Chemicals "Tafmer", density 0.89 g / cm³) 3 Composition X-1 was prepared by blending a black pigment into a resin mixture containing 15% by mass of ) and 20% by mass of polyethylene resin. In addition, unused PP resin (70% by mass), olefin-based elastomer (ethylene-α-olefin random copolymer, "Tafmer" manufactured by Mitsui Chemicals, density 0.89 g / cm³) was used. 3 Composition Y-1 was prepared by blending a black pigment into a resin mixture containing 10% by mass of (X) and 20% by mass of polyethylene resin. Composition X-1 was fed into one of two extruders and composition Y-1 into the other. Composition X-1 was used as the intermediate layer and composition Y-1 was used for both outer layers. The mixture was extruded from a T-die to form a 3-layer structure (outer layer:intermediate layer:outer layer (thickness ratio) = 1:6:1), and a 3-layer sheet with a total thickness of 200 μm and reduced crystallinity was wound up to obtain a 600 m long sheet A. Samples measuring 200 μm in thickness, 100 mm in length, and 10 mm in width were cut from sheet A in both the longitudinal and lateral directions. Tensile tests were performed at a temperature of 90°C and a tensile speed of 500 mm / min. In both directions, the load at which tensile elongation was measured in the range of 50% to 200% was 5.0 to 7.5 N / cm.

[0059] [Manufacturing Example 2] Composition X-2 was prepared by blending a black pigment into a resin mixture containing 75% by mass of recycled PET and 15% by mass of methyl methacrylate-butadiene-styrene (MBS) copolymer as an impact-reinforcement resin. Composition Y-2 was prepared by blending a black pigment into a resin mixture containing 85% by mass of unused PET resin and 15% by mass of MBS copolymer as an impact-reinforcement resin. Composition X-2 was fed into one of two extruders and composition Y-2 into the other. Composition X-2 was used as the intermediate layer and composition Y-2 as both outer layers, resulting in a 2-type, 3-layer structure (outer layer:intermediate layer:outer layer (thickness ratio) = 1:12:1) extruded from a T-die. The extruded sheets were cooled between two cooling rolls at 15°C and 20°C to reduce the degree of crystallinity, and a 3-layer sheet with a total thickness of 200 μm was wound up to obtain a 600 m long sheet B. Samples measuring 200 μm in thickness, 100 mm in length, and 10 mm in width were cut from sheet B in both the longitudinal and lateral directions. Tensile tests were performed at a temperature of 90°C and a tensile speed of 500 mm / min. In both directions, the load at which tensile elongation was measured in the range of 50% to 200% was 4.5 to 7.0 N / cm.

[0060] [Examples 1-7] A resin composition was prepared by mixing an ultraviolet-curing resin (A) and a thermosetting resin (B) to obtain the composition shown in Table 1. Ethyl acetate was added to adjust the viscosity, and a photopolymerization initiator and an ultraviolet absorber were added to prepare the coating agent. As the resin sheet constituting the resin base layer, a 600m roll of sheet A obtained in Manufacturing Example 1 was used. After surface corona treatment of the resin sheet, a coating agent was applied to the treated surface of the resin sheet using a guavia reverse coater so that the cured thickness would be 7-8 μm. After application, the solvent was removed by heating at 70°C for about 1 minute and dried. Then, ultraviolet light with a wavelength of 300 nm × 365 nm was irradiated with a high-pressure mercury lamp to cure the ultraviolet-curable resin (A), and sheet A with a surface protective layer was wound up. Subsequently, the wound sheet A was cured at 50°C for 3 days to completely cure the thermosetting resin (B) and form a surface protective layer, obtaining a decorative sheet.

[0061] [Comparative Examples 1-6] Decorative sheets were prepared in the same manner as in Examples 1 to 7, except that the composition of the resin composition was changed as shown in Table 1.

[0062] [Evaluation Method] The decorative sheets obtained in each example were evaluated for the following properties: adhesion, processability, and scratch resistance.

[0063] (Adhesion) A grid of 2mm x 2mm squares was made on the surface of the protective layer of the decorative sheet using a utility knife, creating a grid of 100 squares. Adhesive tape was attached to the grid, and the tape was peeled off at a 45-degree angle. This process was repeated three times. Afterwards, the percentage of peeled-off pieces in the 100-square grid was calculated, and the adhesion was evaluated according to the following criteria. <Evaluation Criteria> A: Percentage of detached fragments is 0% B: The proportion of detached fragments is 5-10% C: The proportion of detached fragments is 11% or more.

[0064] (processability) A decorative sheet was placed in a vacuum forming chamber and heated, and held for approximately 2 minutes to raise the temperature of the decorative sheet to 100°C. Then, the decorative sheet was placed from above onto a mold having a groove 3 cm deep and 4 cm wide, and molded under reduced pressure. The resulting molded product was removed, visually inspected for cracks and whitening, and evaluated according to the following criteria. <Evaluation Criteria> A: No cracking or whitening. B: There is slight bleaching. C: Cracks and whitening present. D: There are significant cracks and whitening.

[0065] (Scratch resistance) A 1 kg load of steel wool was applied to the surface of the protective layer of the decorative sheet and moved back and forth 10 times. After that, the surface of the protective layer was visually inspected and evaluated according to the following criteria. <Evaluation Criteria> A: There is almost no change in appearance. B: There are some minor scratches or changes on the exterior. C: Significant damage or alteration to the exterior.

[0066] Table 1 shows the evaluation results for Examples 1-7 and Comparative Examples 1-6.

[0067] [Table 1]

[0068] As shown in Table 1, the decorative sheets of Examples 1 to 6, in which a surface protective layer was formed using a resin composition containing an ultraviolet-curing resin (A) and a thermosetting resin (B) in the ratio specified in the present invention, exhibited excellent adhesion, processability, and scratch resistance. On the other hand, the decorative sheets of Comparative Examples 1-2 and 5-6, which did not use UV-curing resin (A), and the decorative sheets of Comparative Examples 3-4, in which the ratio of UV-curing resin (A) to thermosetting resin (B) was inappropriate, lacked adhesion, processability, and scratch resistance.

[0069] [Example 8] A resin composition was prepared by mixing 40 parts by mass of ultraviolet-curing resin (A-1) and 60 parts by mass of thermosetting resin (B-1). Ethyl acetate was added to adjust the viscosity, and then 2 parts by mass of a photopolymerization initiator and 2 parts by mass of an ultraviolet absorber were added to prepare a coating agent. Sheet B obtained in Manufacturing Example 2 was used as the resin sheet constituting the resin substrate layer. A coating agent was applied to the treated surface of the resin sheet using a Guavia reverse coater machine so that the cured thickness would be 10 μm. After application, the solvent was removed and the sheet was dried by passing it through a 70°C heating zone for about 1 minute. Then, ultraviolet light with a wavelength of 300 nm was irradiated to cure the ultraviolet-curable resin (A-1). After that, it was cured at 50°C for 3 days to completely cure the thermosetting resin (B-1) and form a surface protective layer, obtaining a decorative sheet.

[0070] The resulting decorative sheet received an "A" rating for adhesion and a "B" rating for scratch resistance. Furthermore, when a decorative sheet was bonded to a wooden door that had been given a three-dimensional textured surface by router processing using a membrane press molding machine set to approximately 100°C, and then laminated, the result was extremely clean and without any cracking. [Explanation of Symbols]

[0071] 10 decorative sheets 12 Resin base material layer 14 Surface protective layer

Claims

1. In a method for manufacturing a three-dimensionally moldable decorative sheet having at least a resin substrate layer and a surface protective layer, A method for manufacturing a decorative sheet, characterized by applying a resin composition containing the following ultraviolet-curable resin (A) and thermosetting resin (B) in a mass ratio of 30:70 to 60:40 to the surface of a long sheet forming the resin base layer, curing the ultraviolet-curable resin (A) by ultraviolet irradiation and winding it into a roll, and then curing it at 35 to 55°C to completely cure the thermosetting resin (B) and form a surface protective layer. UV-curing resin (A): A UV-curing resin comprising one or more urethane (meth)acrylates selected from polyester, polyether, and polycarbonate types, having 2 to 3 functional groups, and having a pencil hardness of HB to 4B in the cured product. Thermosetting resin (B): A thermosetting resin consisting of an acrylic polyol-based resin and a polyisocyanate compound as a curing agent.

2. The resin substrate layer is made of a polyester or polypropylene sheet having a tensile elongation of 200% or more at 90°C, and a load of 4.0 to 9.0 N / cm in the range of 50% to 200% tensile elongation. The method for manufacturing a decorative sheet according to claim 1, wherein the thickness of the resin substrate layer is 150 to 300 μm.

3. The method for manufacturing a decorative sheet according to claim 2, wherein the polyester sheet having a tensile elongation of 200% or more at 90°C is an amorphous polyester sheet.

4. The method for producing a decorative sheet according to claim 2, wherein the polypropylene sheet having a tensile elongation of 200% or more at 90°C is an amorphous polypropylene sheet containing an olefin elastomer and a polyethylene resin.

5. A method for manufacturing a decorative sheet according to any one of claims 1 to 4, wherein the resin substrate layer is a two-type three-layer or three-type three-layer structure using recycled polyethylene terephthalate resin or recycled polypropylene resin as an intermediate layer.

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