Decorative sheet

Abstract

This decorative sheet comprises: a first layer which has a first resin component that contains 70 mass% or more of a recycled PET-based resin derived from PET bottles, and a white pigment, and which has a thickness of 100 μm to 220 μm inclusive; a second layer which is disposed so as to overlap one surface of the first layer, which has a second resin component that contains 70 mass% or more of a virgin resin, which contains a white pigment in an amount of not less than 17 parts by mass but less than 30 parts by mass with respect to 100 parts by mass of the second resin component, and which has a thickness of 25 μm to 150 μm inclusive; and a third layer which is disposed so as to overlap the other surface of the first layer, which has a third resin component that contains 80 mass% or more of a virgin resin, and which contains a white pigment in an amount of 5 parts by mass or less with respect to 100 parts by mass of the third resin component. The total thickness of the first layer, the second layer, and the third layer is 100 μm to 400 μm inclusive.　

Description

decorative sheet

[0001] This invention relates to a decorative sheet.

[0002] Polyvinyl chloride sheets were once the mainstream material for decorative sheets used on the surfaces of wall coverings, floor coverings, fixtures (doors, etc.), furniture, sinks, and vanity units. In recent years, due to growing concern for environmental issues, sheets mainly composed of polyolefins such as polyethylene, and sheets mainly composed of polyesters such as polyethylene terephthalate (hereinafter also referred to as "PET") have become the mainstream for decorative sheets. There is also a strong demand for the development of decorative sheets using recycled resin made from waste plastic. However, recycled resins are often colored in various colors, and decorative sheets using recycled resin tend to have variations in color.

[0003] The following decorative sheets have been proposed that use recycled resin and have reduced color variation: (1) A decorative sheet made by laminating a recycled polyvinyl chloride sheet with a newly produced polyvinyl chloride sheet having a colored layer (see Patent Document 1). (2) A decorative sheet made of polyester consisting of 3 to 70% by mass of recycled polyester and 30 to 97% by mass of virgin polyester, with 0.1 to 30% by mass of colored pigment (see Patent Document 2). However, in order to suppress color variation, the decorative sheets of (1) and (2) require a high proportion of virgin resin (newly produced resin) raw material, resulting in a low proportion of recycled resin.

[0004] The following have been proposed as sheets with a high proportion of recycled resin: (3) A decorative sheet in which a resin layer (corresponding to a decorative sheet) with a mass ratio of recycled PET / recycled polyethylene / compatibilizer / blue pigment = 85 / 15 / 5 / 1 is laminated to the surface of a steel plate (see paragraph

[0148] of Patent Document 3). (4) A recycled plastic sheet in which 100 parts by mass of recycled PET is blended with 3 to 10 parts by mass of a specific binder and 2 to 5 parts by mass of a modifier consisting of titanium oxide (see Patent Document 4).

[0005] The following decorative sheets have been proposed, which have a high proportion of recycled resin and suppress color variations: (5) A decorative sheet in which the first layer is laminated as the middle layer, the first layer having 70% by mass of recycled PET resin and a white pigment and having a thickness of 151 μm to 184 μm, the second layer having 70% by mass or more of virgin resin and a white pigment and having a thickness of 25 μm to 75 μm, and the third layer having 80% by mass or more of virgin resin and a white pigment of 5 parts by mass or less per 100 parts by mass of virgin resin, the total thickness of the first, second, and third layers is 100 μm to 250 μm, and the total amount of white pigment contained in the first layer and the white pigment contained in the second layer is 11.0 parts by mass or more and 22.2 parts by mass or less per 200 parts by mass of the total of 100 parts by mass of the first layer resin component and 100 parts by mass of the second layer resin component (see Patent Document 5).

[0006] Japanese Patent Publication No. 56-080417, Japanese Patent Publication No. 11-130877, Japanese Patent Publication No. 2009-030062, Japanese Patent Publication No. 2002-348448, Japanese Patent Publication No. 2023-033350

[0007] In recent years, there has been a growing demand for decorative sheets made from recycled resin that offer high brightness, minimize color variations, and enhance aesthetic appeal. For example, in the interior design field, such as furniture, it is necessary to adjust not only the color tone but also the surface's reflective properties. In particular, depending on the application and use of the decorative sheet, a high gloss finish, sometimes called "high gloss," is preferred.

[0008] The resin layer in the decorative panel disclosed in Patent Document 3 is colored blue to suppress color variations due to recycled resin. Therefore, with a formulation like the resin layer in Patent Document 3, the available colors are limited to low-luminosity colors such as dark blue, black, and gray, where color variations due to recycled resin are difficult to discern, making it difficult to use high-luminosity colors such as white and light colors.

[0009] Furthermore, the recycled plastic sheet disclosed in Patent Document 4 is intended for use as a packing material for cooling towers, and titanium dioxide is added in small amounts as a modifier to impart weather resistance. However, when recycled plastic sheets with a low titanium dioxide content are used as decorative sheets, their brightness is low, making it impossible to use bright colors such as white or light colors. In addition, the sheet is transparent, resulting in insufficient opacity as a decorative sheet. Moreover, there is significant color variation between raw material lots and from one part of the sheet to another, making it difficult to achieve a uniform color tone.

[0010] Furthermore, decorative panels and recycled plastic sheets with a high proportion of recycled resin, as disclosed in Patent Documents 3 and 4, tend to have fine foreign matter and impurities contained in the recycled resin raw material that easily become the starting point for cracks when exposed to solvents or chemicals (acids and bases), causing a decrease in the aesthetic appearance and strength of the decorative sheets.

[0011] Furthermore, decorative panels and recycled plastic sheets with a high proportion of recycled resin, as disclosed in Patent Documents 3 and 4, have been found to have reduced adhesion to wall surfaces due to the recycled resin.

[0012] The decorative sheet disclosed in Patent Document 5 uses recycled PET resin in the second layer, which has a greater thickness, thereby increasing the proportion of recycled PET resin in the overall decorative sheet. By having a second and third layer containing virgin resin, it suppresses color variations, a decrease in base resistance, and a decrease in tackiness. On the other hand, Patent Document 5 does not mention gloss or image quality, and there is room for improvement.

[0013] The present invention aims to provide a decorative sheet that exhibits excellent reflective properties such as gloss and image quality while suppressing color variations in high-brightness colors.

[0014] The present invention has the following aspects: <1> A decorative sheet comprising: a first layer having a thickness of 100 μm to 220 μm, which is a first resin component containing 70% by mass or more of recycled PET resin derived from PET bottles and a white pigment; a second layer disposed on one side of the first layer, which has a second resin component containing 70% by mass or more of virgin resin, which contains 17 parts by mass or more and less than 30 parts by mass of the white pigment per 100 parts by mass of the second resin component, which has a thickness of 25 μm to 150 μm; and a third layer disposed on the other side of the first layer, which has a third resin component containing 80% by mass or more of virgin resin, which contains 5 parts by mass or less of the white pigment per 100 parts by mass of the third resin component, wherein the total thickness of the first layer, the second layer and the third layer is 100 μm to 400 μm. <2> The decorative sheet according to <1>, wherein the total amount of the white pigment contained in the first layer and the white pigment contained in the second layer is 20.0 parts by mass or more with respect to 200 parts by mass, which is the total of 100 parts by mass of the first resin component and 100 parts by mass of the second resin component. <3> The decorative sheet according to <1> or <2>, wherein the second resin component further contains the recycled PET resin in a range of 30% by mass or less. <4> The decorative sheet according to <1> or <2>, wherein the third resin component further contains the recycled PET resin in a range of 5% by mass or less. <5> The decorative sheet according to <1> or <2>, wherein the 20° gloss value measured from the second layer side with respect to the first layer is 74% or more. <6> The decorative sheet according to <1> or <2>, wherein the Reflected Image Quality (RIQ) measured from the second layer side with respect to the first layer is 85 or more. <7> The decorative sheet according to <1> or <2>, wherein the L* in the CIE 1976 L*a*b* color space is 90 or more on the surface side of the second layer.

[0015] According to the present invention, it is possible to provide a decorative sheet with high brightness, suppressing color variations, and exhibiting excellent reflective properties such as gloss and image quality.

[0016] This is a cross-sectional view showing the layer structure of a decorative sheet according to one embodiment of the present invention.

[0017] The following definitions of terms apply throughout this specification and the claims. "L*" is a correlation of lightness as defined in JIS Z 8781-4:2013 "Colorimetry - Part IV: CIE 1976 L*a*b* color space" (corresponding international standard ISO 11664-4:2008). "a*" and "b*" are color coordinates as defined in JIS Z 8781-4:2013 "Colorimetry - Part IV: CIE 1976 L*a*b* color space" (corresponding international standard ISO 11664-4:2008). The "~" indicating a numerical range means that the numbers before and after it are included as the lower and upper limits, respectively.

[0018] The following describes a decorative sheet according to one embodiment of the present invention. The embodiments described below are provided to give a better understanding of the spirit of the invention and do not limit the present invention unless otherwise specified.

[0019] <Decorative Sheet> Figure 1 is a cross-sectional view showing the layer structure of a decorative sheet according to one embodiment of the present invention. The decorative sheet 10 of this embodiment has a multi-layer structure comprising a first layer 11, a second layer 12 formed on top of one side 11a of the first layer 11, and a third layer 13 formed on top of the other side 11b of the first layer 11. In this embodiment, the decorative sheet 10 is attached to the wall surface W on the third layer 13 side, for example, via an adhesive layer 14, and the second layer 12 side is exposed to the outside.

[0020] (First Layer) The first layer 11 contains at least a first resin component containing 70% by mass or more of recycled PET resin derived from PET bottles, and a white pigment. The first layer 11 may also contain components other than the first resin component and the white pigment (hereinafter also referred to as "other components (first layer)") as needed, to the extent that the effects of the present invention are not impaired.

[0021] "First resin component (first layer)" The first resin component contains 70% by mass or more of recycled PET resin derived from PET bottles. The first resin component may also contain a resin other than recycled PET resin (hereinafter also referred to as "other resin (first layer)") in an amount of, for example, 30% by mass or less, preferably 10% by mass or less.

[0022] Furthermore, it is preferable that the recycled PET resin is present in an amount of 25% by mass or more relative to the total mass of the decorative sheet 10. If the recycled PET resin is less than 25% by mass, the proportion of virgin resin contained in the second layer 12, which will be described later, will be relatively high, and the significance of using recycled PET resin as an environmental measure will decrease.

[0023] Recycled PET resin is a recycled resin derived from PET bottles, and is preferred as crushed PET bottle material due to its low cost and easy availability. The recycled PET resin may also include crushed materials such as labels (including printing and adhesives) and caps that were attached to the PET bottles, to the extent that it does not impair the effects of the present invention.

[0024] For example, in Japan, in order to prevent a decline in the quality of recycled products, the voluntary design guidelines described below stipulate that designated PET bottles must be made of pure PET (no substances other than the main PET material are added or combined), and that they must not be colored (excluding the white color due to crystallization of the spout). Therefore, currently, no colored PET bottles are produced in Japan, and there is a request that colored PET bottles produced overseas for the Japanese market be changed to uncolored PET bottles (http: / / www.petbottle-rec.gr.jp / qanda / sec13.html).

[0025] Regarding PET bottles distributed within Japan, the details are specified in the "Voluntary Design Guidelines for Designated PET Bottles," which were established by the PET Bottle Recycling Promotion Council under the guidance of the government (http: / / www.petbottle-rec.gr.jp / guideline / jisyu.html).

[0026] These voluntary design guidelines were established by the PET Bottle Recycling Promotion Council to ensure that PET bottles (designated PET bottles) used for designated products (soft drinks, dairy drinks, alcoholic beverages, and specific seasonings) under the Law for Promotion of Effective Utilization of Resources are containers with excellent reusability, including reprocessing after use and hygiene, and specify the bottles, labels (including printing and adhesives), caps, etc. to be used.

[0027] While it is a given that members (organizations and companies) of the PET Bottle Recycling Promotion Council must comply with the voluntary design guidelines, even non-members are required to comply with the voluntary design guidelines if they manufacture, import, or sell beverages, alcoholic beverages, or specific seasonings in designated PET bottles, or if they manufacture or import designated PET bottles and their accompanying packaging materials, provided that they are sold or used within Japan.

[0028] Therefore, most PET bottles distributed domestically are uncolored, and recycled PET resin derived from PET bottles is almost transparent. However, although recycled PET resin is almost transparent, it tends to be yellowish-black (high b* value and low L* value in the CIE 1976 L*a*b* color space) due to the heat history it receives during thermoforming and the presence of labels, etc. For this reason, there has been hesitation to use recycled PET resin as a material for high-brightness white or light-colored decorative sheets.

[0029] In the present invention, as will be described later, a second layer 12 is formed on top of the first layer 11 and exposed to the outside, and this second layer 12 contains a second resin component mainly composed of virgin resin, making it possible to use recycled PET resin as a constituent material for a highly white or light-colored decorative sheet 10 without worrying about a decrease in brightness.

[0030] The crystallization temperature of recycled PET resin is preferably 145°C or lower, more preferably 120 to 145°C, and even more preferably 125 to 140°C. The crystallization temperature of recycled PET resin is measured using a thermal analyzer (such as a differential scanning calorimetry (DSC)).

[0031] The intrinsic viscosity (IV value) of the recycled PET resin is preferably 0.60 or higher, more preferably 0.65 to 0.85, and even more preferably 0.70 to 0.83. If the intrinsic viscosity (IV value) of the recycled PET resin is below the lower limit of the above range, problems may arise in extrusion moldability due to a decrease in melt viscosity when pigment is added. If the intrinsic viscosity (IV value) of the recycled PET resin is above the upper limit of the above range, problems may arise in extrusion moldability due to high viscosity. The intrinsic viscosity (IV value) of the recycled PET resin is measured by the test method described in JIS K 7390:2003.

[0032] The b* value of recycled PET resin in the CIE 1976 L*a*b* color space is preferably 9 or less, more preferably -6 to 8, and even more preferably 0 to 7. The b* value of recycled PET resin is measured by the test method described in JIS K 7390:2003. The L* value of recycled PET resin in the CIE 1976 L*a*b* color space is preferably 65 or more, more preferably 68 or more, and even more preferably 70 or more. If the L* value of recycled PET resin is above the lower limit of the above range, it is easier to manufacture white or light-colored decorative sheets 10 with high brightness.

[0033] Other resins included in the first resin component (first layer) include resins used in masterbatches containing white pigments, and resins added for purposes such as suppressing color variations in decorative sheets and improving the properties of decorative sheets. Specific examples of other resins include virgin PET resins, recycled resins other than recycled PET resins (excluding polyvinyl chloride), and virgin resins other than virgin PET resins (excluding polyvinyl chloride).

[0034] "White Pigments (First Layer)" Examples of white pigments for the first layer 11 include titanium dioxide, zinc oxide, calcium carbonate, magnesium oxide, and lithopone. Titanium dioxide is preferred as a white pigment due to its high opacity. Examples of titanium dioxide include rutile-type titanium dioxide and anatase-type titanium dioxide, with rutile-type titanium dioxide being preferred due to its low catalytic activity.

[0035] The content of the white pigment in the first layer 11 is not particularly limited, but is preferably 5 to 15 parts by mass, more preferably 6 to 12 parts by mass, and still more preferably 6 to 10 parts by mass, relative to 100 parts by mass of the first resin component. By incorporating a white pigment into the first layer 11, which serves as the lower layer of the second layer 12 described later, it is possible to prevent the brightness of the decorative sheet 10 from decreasing due to color transmission even when the thickness of the second layer 12 exposed to the outside is reduced. When the content of the white pigment is not less than the lower limit of the above range, a white or light-colored decorative sheet 10 with high brightness and little color variation between raw material lots and between different positions of the sheet can be obtained. When the content of the white pigment is not more than the upper limit of the above range, abnormal extrusion behavior (such as width abnormality caused by a decrease in melt viscosity) can be suppressed, and good moldability is achieved when manufacturing the decorative sheet 10.

[0036] "Other components (first layer)" As other components of the first layer 11, mention may be made of pigments other than white pigments, compatibilizers, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, storage stabilizers, lubricants, fillers and the like. The content of other components is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and still more preferably 5 parts by mass or less, relative to 100 parts by mass of the first resin component.

[0037] The thickness of the first layer 11 having the composition described above is 100 μm to 220 μm, preferably 100 μm to 200 μm, and more preferably 150 μm to 200 μm.

[0038] When the first layer 11 has a thickness not less than the lower limit of the above thickness range, it is easy to increase the mechanical strength and hiding power of the decorative sheet 10, and a sufficient proportion of recycled PET-based resin can be secured in the entire decorative sheet 10. When the first layer 11 has a thickness not more than the upper limit of the above thickness range, the three-dimensional processability, flexibility and the like of the decorative sheet 10 become favorable.

[0039] (Second layer) The second layer 12 contains at least a second resin component containing 70% by mass or more of virgin resin (newborn resin), and a white pigment. The second layer 12 may optionally contain components other than the second resin component and the white pigment (hereinafter also referred to as "other components (second layer)") within a range that does not impair the effects of the present invention.

[0040] "Second Resin Component (Second Layer)" The second resin component contains 70% by mass or more of virgin resin. In addition, the second resin component may contain a resin other than virgin resin (hereinafter also referred to as "other resin (second layer)") in an amount of 30% by mass or less, preferably 10% by mass or less.

[0041] Virgin resin is a resin newly produced from a resin raw material containing almost no impurities. From the viewpoint of improving the bondability to the first layer (11), copolymers having ethylene glycol and terephthalic acid as main monomers (PET, PET-G), polycarbonate, and polyacrylic acid polymers are preferred.

[0042] By including 70% by mass or more of virgin resin as the second resin component of the second layer (12) covering the first layer (11) in the decorative sheet (10), the brightness of the externally exposed second layer (12) can be made higher than the brightness of the first layer containing 70% by mass or more of recycled PET-based resin. As a result, even when the decorative sheet (10) uses recycled PET-based resin in an amount accounting for 25% by mass or more of the total resin components of the decorative sheet (10), high brightness can be maintained in terms of appearance.

[0043] Examples of other resins contained in the second resin component include resins used in masterbatches containing white pigments, and resins added for purposes such as suppressing color variation of decorative sheets and improving the properties of decorative sheets. Specific examples of other resins include virgin resins other than virgin PET-based resins (excluding polyvinyl chloride), recycled PET-based resins, and recycled resins other than recycled PET-based resins (excluding polyvinyl chloride). For example, as another resin contained in the second resin component, recycled PET-based resin can be contained in an amount of 30% by mass or less.

[0044] "White Pigment (Second Layer)" As for the white pigment of the second layer 12, similar to the first layer 11, titanium dioxide, zinc oxide, calcium carbonate, magnesium oxide, lithopone, etc., can be used. Titanium dioxide is preferred as the white pigment due to its high opacity. Examples of titanium dioxide include rutile-type titanium dioxide and anatase-type titanium dioxide, with rutile-type titanium dioxide being preferred due to its low catalytic activity. The white pigment of the second layer 12 may be the same as that of the white resin of the first layer 11, or different from those of the first layer 11 may be selected.

[0045] The content of the white pigment in the second layer 12 is 17 parts by mass or more, preferably 20 parts by mass or more, and more preferably 22 parts by mass or more, per 100 parts by mass of the second resin component. If the content of the white pigment is above the lower limit of the above range, a white or light-colored decorative sheet 10 can be obtained that has less color variation between raw material lots and from place to place on the sheet, excellent reflective properties such as gloss and image quality, and high brightness. In addition, the content of the white pigment in the second layer 12 may be less than 30 parts by mass, less than 28 parts by mass, or less than 25 parts by mass, per 100 parts by mass of the second resin component. If the content of the white pigment is below the upper limit of the above range, abnormalities in extrusion behavior (such as width abnormalities due to a decrease in melt viscosity) are suppressed, and the moldability when manufacturing the decorative sheet 10 is good.

[0046] "Other components (second layer)" Other components of the second layer 12 include pigments other than white pigments, compatibilizers, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, preservative stabilizers, lubricants, fillers, etc. The content of the other components is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, per 100 parts by mass of the second resin component.

[0047] The thickness of the second layer 12, having the composition described above, is desirable to be above a certain thickness in order to cover the first layer 11, which contains 70% or more by mass of recycled PET resin, and to prevent penetration into the first layer 11, which has low chemical and solvent resistance. The thickness of the second layer 12 is 25 μm to 150 μm, preferably 25 μm to 125 μm, and more preferably 50 μm to 100 μm.

[0048] By maintaining this thickness range, the first layer 11, which contains recycled PET resin and has low brightness, is prevented from showing through the second layer 12 that is exposed to the outside of the decorative sheet 10, thus preventing a decrease in the apparent brightness of the decorative sheet 10. Furthermore, if the second layer 12 is too thick, the proportion of recycled PET resin used in the entire decorative sheet 10 decreases, reducing the significance of using recycled PET resin.

[0049] (Third Layer) The third layer 13 contains at least a third resin component containing 80% by mass or more of virgin resin (newly produced resin). The third layer 13 may also further contain a white pigment in an amount of 5 parts by mass or less per 100 parts by mass of the third resin component. Furthermore, the third layer 13 may contain components other than the third resin component and selectively included white pigment (hereinafter also referred to as "other components (third layer)") as needed, to the extent that the effects of the present invention are not impaired.

[0050] "Third resin component (third layer)" The third resin component contains 80% by mass or more of virgin resin. The third resin component may also contain a resin other than virgin resin (hereinafter also referred to as "other resin (third layer)") in an amount of, for example, 20% by mass or less, preferably 10% by mass or less.

[0051] Virgin resin is a resin newly manufactured from resin raw materials that contain almost no impurities. From the viewpoint of improving adhesion to the first layer 11 and adhesion to the wall surface W via the adhesive layer 14, copolymers mainly composed of ethylene glycol and terephthalic acid (PET, PET-G), polycarbonate, and polyacrylic acid polymers are preferred. The virgin resin used for the third layer 13 may be the same as the virgin resin used for the second layer 12, or different types of virgin resins may be used.

[0052] In the decorative sheet 10, by including 80% by mass or more of virgin resin as the third resin component of the third layer 13 that covers the first layer 11, the adhesion of the third layer 13 to the wall surface W, which forms the surface on which the decorative sheet 10 is adhered to the wall surface W, is improved. Furthermore, by not including white pigments, or limiting them to 5 parts by mass or less per 100 parts by mass of the third resin component, a decrease in adhesion due to dispersants contained in white pigments can be prevented.

[0053] Other resins that can be included in the third resin component include virgin resins other than virgin PET resins (excluding polyvinyl chloride), recycled PET resins, and recycled resins other than recycled PET resins (excluding polyvinyl chloride). For example, recycled PET resin can be included in the third resin component in an amount of 20% by mass or less.

[0054] "White Pigment (Third Layer)" It is preferable that the third layer 13 does not contain a white pigment, but if it is included, examples include titanium dioxide, zinc oxide, calcium carbonate, magnesium oxide, lithopone, etc., similar to the first layer 11. As a white pigment, titanium dioxide is preferred due to its high opacity. Examples of titanium dioxide include rutile-type titanium dioxide and anatase-type titanium dioxide, and rutile-type titanium dioxide is preferred due to its low catalytic activity. The white pigment of the third layer 13 may be the same as that of the white resin of the first layer 11 and the second layer 12, or different from those of the first layer 11 and the second layer 12.

[0055] "Other components (third layer)" Other components of the third layer 13 include pigments other than white pigments, compatibilizers, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, preservative stabilizers, lubricants, fillers, etc. The content of the other components is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, per 100 parts by mass of the third resin component.

[0056] The thickness of the third layer 13, having the composition described above, is preferably above a certain thickness in order to cover the first layer 11, which contains 70% or more by mass of recycled PET resin, and to prevent penetration into the first layer 11, which has low chemical and solvent resistance. The thickness of the third layer 13 is preferably 15 μm to 70 μm, and more preferably 25 μm to 40 μm.

[0057] By maintaining this thickness range, it is possible to prevent a decrease in adhesion caused by the dispersant in the pigment contained in the recycled PET resin of the first layer 11 penetrating to the adhesive layer 14 of the third layer 13 and bleeding out. Furthermore, if the third layer 13 is too thick, the proportion of recycled PET resin used in the entire decorative sheet 10 decreases, reducing the significance of using recycled PET resin.

[0058] Furthermore, as shown in Figure 2, the decorative sheet 10 may, if necessary, have a fourth layer formed on the side of the second layer 12 opposite to the first layer 11, as long as it does not impair the effects of the present invention. For example, the decorative sheet 10 may have a first layer 11, a second layer 12 formed overlapping one side 11a of the first layer 11, a third layer 13 formed overlapping the other side 11b of the first layer 11, and a fourth layer 15 formed overlapping the second layer 12 on the side of the second layer 12 opposite to the first layer 11.

[0059] (Fourth layer) The fourth layer 15 contains at least a fourth resin component. The fourth resin component is not particularly limited, and is, for example, an energy curable resin. The "energy curable resin" is typically in a liquid state, and refers to an organic compound having a functional group that polymerizes (or crosslinks) when energy such as light (typically ultraviolet light) or heat is applied thereto. Examples of such polymerizable functional groups include (meth)acryloyl groups, vinyl groups, and allyl groups. The energy curable resin is not particularly limited as long as it is an organic compound having the above-mentioned polymerizable functional group, and conventionally known photocurable resins and thermosetting resins can be used without particular limitation. Specific examples of such energy curable resins include polyfunctional monomers, polyfunctional oligomers, polyfunctional polymers, etc. that contain a plurality of the above-mentioned polymerizable functional groups (typically vinyl groups or (meth)acryloyl groups) in the molecule. These energy curable resins may be used alone or in combination of two or more. For example, by using a mixture of a polyfunctional (meth)acrylate monomer and a polyfunctional (meth)acrylate polymer as the energy curable resin, a hard coat resin composition that cures easily can be obtained.

[0060] In addition, the fourth layer 15 may contain other components that are selectively included as necessary within a range that does not impair the effects of the present invention (hereinafter also referred to as "other components (fourth layer)"). The other components of the fourth layer 15 are not particularly limited, and are, for example, inorganic particles. Examples of materials for the inorganic particles include silica (SiO ２ ), alumina (Al ２ O ３ ), zirconia (ZrO ２ ), titania (TiO ２ ), ITO (tin-doped indium oxide), tin oxide (SnO ２ ), zinc oxide (ZnO) and antimony oxide (Sb ２ O ３ , Sb ２ O ５One or more types selected from the above are examples. The shape of the inorganic particles is not particularly limited, but for example, it is spherical. Other components of the fourth layer 15 may include spherical alumina particles. This makes it possible to improve impact resistance and scratch resistance after curing, as well as to reduce light diffusion (HAZE) and form a hard coat with excellent transparency.

[0061] The thickness of the fourth layer 15 is preferably 0.1 μm to 8 μm, and more preferably 0.1 μm to 5 μm.

[0062] If the fourth layer 15 is within the aforementioned thickness range, surface functionality can be imparted without affecting the appearance.

[0063] (Overall composition of the decorative sheet) The total thickness of the first layer 11, the second layer 12, and the third layer 13 is 100 μm or more and 400 μm or less, preferably 100 μm or more and 350 μm or less, and more preferably 150 μm or more and 250 μm or less. If the total thickness of the first layer 11, the second layer 12, and the third layer 13 is above the lower limit of the above range, the mechanical strength and opacity of the decorative sheet 10 are easily increased. If the total thickness of the first layer 11, the second layer 12, and the third layer 13 is below the upper limit of the above range, the three-dimensional processability and flexibility of the decorative sheet 10 will be improved.

[0064] The total amount of the white pigment contained in the first layer 11 and the white pigment contained in the second layer 12 is preferably 20.0 parts by mass or more, more preferably 22.0 parts by mass or more, and even more preferably 24.0 parts by mass or more, relative to the total of 200 parts by mass of the first resin component and 100 parts by mass of the second resin component. This prevents a decrease in the brightness of the decorative sheet 10 due to color transmission, and results in a highly bright white or light-colored decorative sheet 10 with little color variation between raw material lots and from place to place on the sheet. Furthermore, the total amount of the white pigment contained in the first layer 11 and the white pigment contained in the second layer 12 may be 45 parts by mass or less, 40 parts by mass or less, or 35 parts by mass or less, relative to the total of 200 parts by mass of the first resin component and 100 parts by mass of the second resin component.

[0065] The 20° gloss value of the decorative sheet 10, measured from the surface side of the second layer 12, is preferably 74% or higher, and more preferably 75% or higher. By setting the 20° gloss value within this range, the glossiness stands out against high-brightness colors, improving aesthetics. The 20° gloss value is calculated based on JIS Z 8741:1997.

[0066] The Reflected Image Quality (RIQ) measured from the surface side of the second layer 12 of the decorative sheet 10 is preferably 85 or higher, more preferably 90 or higher, and even more preferably 95 or higher. By setting the RIQ within this range, distortion and blurring of the reflected image as seen by the naked eye can be reduced, improving aesthetics. The RIQ is measured using an appearance analyzer (Rhopoint IQ-S, manufactured by Rhopoint).

[0067] On the surface side of the second layer 12 of the decorative sheet 10, the L* in the CIE 1976 L*a*b* color space is preferably 90 or higher, more preferably 92 or higher, and even more preferably 95 or higher. This makes it possible to produce a decorative sheet 10 with high brightness, such as white or light color. The L* of the decorative sheet 10 is measured according to JIS Z 8781-4:2013.

[0068] Furthermore, in the second layer 12, the arithmetic mean roughness (Ra), measured from the second layer side with respect to the first layer, is preferably 0.4 μm or less, more preferably 0.2 μm or less, and even more preferably 0.1 μm or less. By achieving this arithmetic mean roughness range, a decorative sheet with high gloss and image quality can be obtained. The arithmetic mean roughness (Ra) is measured in accordance with JIS B 0601:2013.

[0069] The decorative sheet 10 of this embodiment may have functional layers to provide various functions as needed, within the limits that do not impair the effects of the present invention. Examples of functional layers include coating layers, transfer layers, and printing layers to provide stain resistance and weather resistance. The surface shape of the second layer forming the surface of the decorative sheet 10 is not particularly limited and may be smooth or may have an uneven shape due to embossing or the like. Furthermore, if a fourth layer 15 is provided on the decorative sheet 10, the surface shape of the fourth layer forming the surface of the decorative sheet 10 is not particularly limited and may be smooth or may have an uneven shape due to embossing or the like.

[0070] The decorative sheet 10 of this embodiment is obtained, for example, by heating, melting, and kneading resin mixtures containing resin components and white pigments that constitute the first layer 11, the second layer 12, and the third layer 13, and then co-extruding them into a multilayer sheet. For example, the resin constituting the first layer 11, the resin constituting the second layer 12, and the resin constituting the third layer 13 are supplied to a co-extrusion molding machine, and a decorative sheet 10 consisting of the first layer 11, the second layer 12, and the third layer 13 is formed by co-extruding at about 200°C using a feed block type T-die.

[0071] Alternatively, the decorative sheet 10 can be obtained by forming the resin mixture into sheets, and then joining the second layer 12 to one side 11a of the obtained first layer 11 and the third layer 13 to the other side 11b. Examples of methods for forming the resin mixture include extrusion molding and calendering. The decorative sheet 10 may be unstretched or stretched.

[0072] In the embodiment described above, the decorative sheet 10 is composed of three layers: a first layer 11, a second layer 12, and a third layer 13. However, any additional functional layers can be formed between each of these layers.

[0073] (Mechanism of Action) In the decorative sheet 10 of this embodiment described above, the first resin component of the first layer 11 contains 70% by mass or more of recycled PET resin derived from PET bottles. Therefore, it is more environmentally friendly than decorative sheets containing polyvinyl chloride or decorative sheets with a low proportion of recycled resin in the total resin components.

[0074] Furthermore, in the decorative sheet 10 of this embodiment, a second layer 12 having a second resin component containing 70% or more by mass of virgin resin is placed on top of a first layer 11 containing a large amount of recycled PET resin. As a result, the surface of the decorative sheet 10 that is exposed to the outside becomes this second layer 12, which allows for a high level of brightness in appearance and makes it possible to realize a decorative sheet 10 with less unevenness in color tone.

[0075] Furthermore, the second layer 12 located on the outer surface of the decorative sheet 10 has a second resin component containing 70% by mass or more of virgin resin. This makes it possible to create a decorative sheet 10 that is less prone to cracks caused by bases in impurities, which can occur when the proportion of recycled resin is high, thus preventing a decrease in surface aesthetics and strength.

[0076] Furthermore, the second layer 12 located on the outer surface of the decorative sheet 10 contains 17 parts by mass or more of a white pigment per 100 parts by mass of the second resin component. This allows for greater light reflection due to the white pigment being more abundant in the visible layer, resulting in a decorative sheet 10 with excellent reflective properties such as gloss and image quality.

[0077] Furthermore, in the decorative sheet 10 of this embodiment, if a third layer 13 having a third resin component containing 80% or more by mass of virgin resin is provided on top of the first layer 11 which contains a large amount of recycled PET resin, the decorative sheet 10 will be bonded to the wall surface W by this third layer 13. This prevents the decrease in adhesion that occurs when the proportion of recycled resin is high, due to the dispersant in the pigment bleeding out to the surface of the decorative sheet. Therefore, even if the first layer 11 contains a large amount of recycled PET resin, a decorative sheet 10 with good adhesion can be realized.

[0078] The decorative sheet of the present invention is used on the surface of wall materials, floor materials, fixtures (doors, etc.), furniture, sinks, vanity units, etc., and is preferably used on the surface of doors of furniture, sinks, vanity units, etc.

[0079] Although embodiments of the present invention have been specifically described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0080] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0081] "Evaluation Method" - Using a surface color spectrophotometer (CCM) (Konica Minolta Japan, CM-3600A), measurements were taken at three locations on the decorative sheet under the conditions of light source D65 and viewing angle of 10°. L*, a*, and b* in the CIE 1976 L*a*b* color space were determined, and the average value of the three locations was used.

[0082] - Glossiness: In accordance with JIS Z 8741:1997, an appearance analyzer (Rhopoint IQ-S, manufactured by Rhopoint) was used to measure the glossiness at 20° by illuminating the surface of the second layer of the decorative sheet with light incident at an incidence angle of 20°. The specular reflected light flux was measured, and the 20° glossiness was determined. The above measurement was performed five times, and the average value was calculated.

[0083] - The Image Clarity Index (RIQ) was measured from the surface of the second layer of the decorative sheet using a Rhopoint IQ-S image clarity analyzer. The above measurement was performed five times, and the average value was calculated.

[0084] - Arithmetic mean roughness Ra: The arithmetic mean roughness Ra of the second layer surface of the decorative sheet was calculated in accordance with JIS B 0601:2013.

[0085] (Example 1) First layer: A resin mixture was used, which consisted of recycled PET resin {ALIPLAST Co., Ltd., trade name "Alimpet" (Italian recycled PET bottle resin)} with a masterbatch (containing titanium dioxide and virgin A-PET resin) added. The content of white pigment relative to the resin component is shown in Table 1. Second layer: A resin mixture was used, which consisted of PET-G resin (virgin resin, SK Chemical Co., Ltd., trade name "K2012") with a masterbatch (containing titanium dioxide and virgin PET-G) added. The content of white pigment relative to the resin component is shown in Table 1. Third layer: PET-G resin (virgin resin, SK Chemical Co., Ltd., trade name "K2012") was used. The above raw materials were extruded from a T-die at 265°C using a co-extrusion method with a three-layer extruder, and cast onto a cooling roll at 40°C to obtain a sheet with a total layer thickness of 250 μm, with the second, first, and third layers being 87.5 μm, 137.5 μm, and 25 μm respectively.

[0086] Fourth layer: On the second layer side of the sheet obtained above, a coating solution was applied by bar coating by mixing 100 parts by mass of a resin obtained by mixing 50 parts by mass of dipentaerythritol hexaacrylate (manufactured by Daicel Ornex) and 50 parts by mass of urethane acrylate (manufactured by Mitsubishi Chemical Corporation, trade name "UV-6640B") with 5 parts by weight of polymerization initiator (manufactured by IGM Resins B.V., trade name "Omnirad 1173") solution and 195 parts by weight of methyl ethyl ketone. This coating solution was then applied, dried, and irradiated with ultraviolet light to form a fourth layer with a thickness of 4.0 μm, resulting in a decorative sheet composed of the fourth layer / second layer / first layer / third layer.

[0087] (Example 2) The decorative sheet of Example 2 was obtained in the same manner as in Example 1, except that the thickness of the first layer was 145 μm, the thickness of the second layer was 70 μm, the content of the white pigment was changed to 18 parts by mass per 100 parts by mass of the second resin component, and the thickness of the third layer was 35 μm.

[0088] (Example 3) The decorative sheet of Example 3 was obtained in the same manner as in Example 1, except that a fourth layer was not formed on the second layer, and a decorative sheet consisting of the second layer / first layer / third layer was obtained.

[0089] (Example 4) The decorative sheet of Example 4 was obtained in the same manner as in Example 1, except that the thickness of the first layer was 220 μm, the thickness of the second layer was 140 μm, and the thickness of the third layer was 40 μm.

[0090] (Example 5) The decorative sheet of Example 5 was obtained in the same manner as in Example 1, except that the content of the white pigment in the second layer was changed to 25 parts by mass per 100 parts by mass of the second resin component, and a fourth layer was not formed on the second layer, resulting in a decorative sheet composed of the second layer / first layer / third layer.

[0091] (Example 6) The decorative sheet of Example 6 was obtained in the same manner as in Example 1, except that the thickness of the first layer was 155 μm, the second resin component of the second layer was changed to PET-G, and the thickness of the second layer was 50 μm.

[0092] (Comparative Example 1) A decorative sheet of Comparative Example 1 was obtained in the same manner as in Example 6, except that the content of the white pigment in the first layer was changed to 5 parts by mass per 100 parts by mass of the first resin component, the content of the white pigment in the second layer was changed to 12 parts by mass per 100 parts by mass of the second resin component, and the thickness of the third layer was set to 45 μm.

[0093] (Comparative Example 2) A decorative sheet for Comparative Example 2 was obtained in the same manner as in Example 1, except that the thickness of the first layer was set to 155 μm and the content of the white pigment was changed to 1 part by mass per 100 parts by mass of the first resin component, the thickness of the second layer was set to 50 μm and the content of the white pigment was changed to 4.5 parts by mass per 100 parts by mass of the second resin component, and the thickness of the third layer was set to 45 μm.

[0094] (Comparative Example 3) A decorative sheet of Comparative Example 3 was obtained in the same manner as in Example 6, except that the content of the white pigment in the first layer was changed to 0.5 parts by mass per 100 parts by mass of the first resin component, the content of the white pigment in the second layer was changed to 2 parts by mass per 100 parts by mass of the second resin component, and the thickness of the third layer was set to 45 μm.

[0095] (Comparative Example 4) A decorative sheet for Comparative Example 4 was obtained in the same manner as in Example 1, except that the content of the white pigment in the second layer was changed to 30 parts by mass per 100 parts by mass of the second resin component, and a fourth layer was not formed on the second layer, resulting in a decorative sheet composed of the second layer / first layer / third layer.

[0096] (Comparative Example 5) A decorative sheet of Comparative Example 5 was obtained in the same manner as in Example 1, except that the first resin component of the first layer was changed to PVC resin (straight PVC resin with an average degree of polymerization of 700), the thickness was set to 214.5 μm, and the content of white pigment was changed to 9 parts by mass per 100 parts by mass of the first resin component; the second resin component of the second layer was changed to PVC, the thickness was set to 82.5 μm, and the content of white pigment was changed to 9 parts by mass per 100 parts by mass of the second resin component; the third resin component of the third layer was changed to PVC, the thickness was set to 33 μm, and the white pigment content of the third layer was changed to 9 parts by mass per 100 parts by mass of the third resin component.

[0097] Table 1 shows the composition and evaluation results of the samples for Examples 1 to 6, and Table 2 shows the composition and evaluation results of the samples for Comparative Examples 1 to 5.

[0098]

[0099]

[0100] As shown in Table 1, Examples 1 to 6 showed high L*, 20° gloss value, and Image Clarity Index (RIQ), indicating excellent surface color tone, gloss, and image quality. On the other hand, as shown in Table 2, Comparative Examples 1 to 3 and 5 showed low L*, 20° gloss value, and Image Clarity Index (RIQ), indicating poor surface color tone, gloss, and image quality. Comparative Example 4 was also unsuitable for molding. From these examples, the excellent surface color tone, gloss, and image quality of the decorative sheet of the present invention were confirmed.

[0101] The decorative sheet of the present invention is environmentally friendly, has excellent reflective properties such as gloss and image quality, and is useful as a white or light-colored decorative sheet with high brightness.

[0102] 10... Decorative sheet 11... First layer 12... Second layer 13... Third layer 14... Adhesive layer 15... Fourth layer W... Wall surface

Claims

1. A decorative sheet comprising: a first layer having a thickness of 100 μm to 220 μm, comprising a first resin component containing 70% by mass or more of recycled PET resin derived from PET bottles and a white pigment; a second layer disposed on one side of the first layer, comprising a second resin component containing 70% by mass or more of virgin resin, with a white pigment in an amount of 17 parts by mass or more and less than 30 parts by mass per 100 parts by mass of the second resin component, and a thickness of 25 μm to 150 μm; and a third layer disposed on the other side of the first layer, comprising a third resin component containing 80% by mass or more of virgin resin, with a white pigment in an amount of 5 parts by mass or less per 100 parts by mass of the third resin component, wherein the total thickness of the first, second, and third layers is 100 μm to 400 μm.

2. The decorative sheet according to claim 1, wherein the total amount of the white pigment contained in the first layer and the white pigment contained in the second layer is 20.0 parts by mass or more with respect to the total of 200 parts by mass of 100 parts by mass of the first resin component and 100 parts by mass of the second resin component.

3. The decorative sheet according to claim 1 or 2, wherein the second resin component further comprises the recycled PET resin in an amount of 30% by mass or less.

4. The decorative sheet according to claim 1 or 2, wherein the third resin component further comprises the recycled PET resin in an amount of 5% by mass or less.

5. The decorative sheet according to claim 1 or 2, wherein the 20° gloss value measured from the second layer side with respect to the first layer is 74% or more.

6. The decorative sheet according to claim 1 or 2, wherein the Reflected Image Quality (RIQ) measured from the second layer side with respect to the first layer is 85 or higher.

7. The decorative sheet according to claim 1 or 2, wherein the L* in the CIE 1976 L*a*b* color space is 90 or higher on the surface side of the second layer.

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