JP7255187B2 - Decorative sheet and board - Google Patents

Description

TECHNICAL FIELD The present invention relates to a decorative sheet and a decorative board.

For decorative sheets used for building interior materials and surfaces of fittings, especially for decorative sheets used in public places, the noncombustible materials described in Article 108-2, Item 1 and Item 2 of the Enforcement Order of the Building Standards Law It is required to meet the technical standards of Conventionally, a decorative sheet containing a soft polyvinyl chloride resin has been used as a decorative sheet that satisfies the technical standards for such noncombustible materials. However, the decorative sheet containing a soft polyvinyl chloride resin has a problem of generating toxic gas and the like during incineration after disposal.

Therefore, in recent years, decorative sheets using polyolefin-based resins have been proposed instead of polyvinyl chloride-based resins. However, when polyolefin resin is used for decorative sheets, the generation of toxic gases during combustion is suppressed. May be a source of gas.
As a decorative sheet using a polyolefin resin that satisfies the technical standards for noncombustible materials described in the above-mentioned laws and regulations and can suppress the generation of greenhouse gases, for example, the sheets described in Patent Documents 1 and 2 are available. be. The patent documents 1 and 2 disclose a structure using a polyolefin resin layer containing an inorganic filler such as calcium carbonate.

JP 2013-010931 A JP 2011-122293 A

As mentioned above, it is difficult to dramatically reduce the amount of greenhouse gases generated during manufacturing defects and disposal of used products with decorative sheets made of polyolefin resin that meet the technical standards for noncombustible materials. be. From the viewpoint of preventing global warming, it is important to reduce environmental load by recycling decorative sheet materials.
A problem in recycling the base material for the decorative sheet, that is, the base material for the decorative sheet, is the easy peelability between the base material for the decorative sheet and the transparent resin layer. In many conventional decorative sheets, the print layer and the base material for decorative sheet made of polyolefin resin under the printed layer are strongly bonded, and the printed layer and the base material for decorative sheet are not easily peeled off. Therefore, it may not be possible to separate the decorative sheet base material from the laminate including the layers above the printed layer. On the other hand, if the interfacial adhesive strength between the base material for the decorative sheet and the printed layer is lowered too much, the base material for the decorative sheet and the printed layer will unintentionally separate during use due to deterioration over time. A problem arose, and it was difficult to recycle and use the decorative sheet base material.

The present invention has been made by paying attention to the points as described above. An object of the present invention is to provide a laminated stretched film, a decorative sheet base material, a decorative sheet, and a decorative board, in which peeling between a base material for a decorative sheet and a laminate thereof over time is reduced.

In order to solve the above problems, a laminated stretched film according to an aspect of the present invention is a uniaxially or biaxially laminated stretched film, and has a plurality of layers in which the main component of the resin material is a polypropylene resin. , when the first layer located on the outermost surface among the plurality of layers is defined as the surface layer, and the layer other than the surface layer among the plurality of layers is defined as the core layer, the surface layer is IR The peak intensity ratio by spectroscopy is less than 30 and the peak intensity ratio by Raman spectroscopy is less than 6.0, and the core layer has a peak intensity ratio by IR spectroscopy of 43 or more, or a peak intensity by Raman spectroscopy The gist is that the ratio is 2.0 or more.
Further, a decorative sheet according to one aspect of the present invention uses the laminated stretched film according to one aspect as a base material for a decorative sheet, and contains a polyolefin-based resin formed on the surface of the base material for the decorative sheet on the surface layer side. The gist is to provide a transparent resin layer of one layer or a plurality of layers.

According to one aspect of the present invention, a base material for a decorative sheet and a laminate of the base material and the laminate thereof are provided while maintaining easy peelability between the base material for the decorative sheet and the laminate including a transparent resin layer provided above the printed layer. Detachment over time can be reduced.
In one aspect of the present invention, the base material for decorative sheet is uniaxially or biaxially stretched, and the peak intensity ratio by IR spectroscopy and the peak intensity ratio by Raman spectroscopy are adjusted to obtain a surface layer and a core layer. delamination is induced, and the transparent resin layer can be peeled off together with the surface layer and the printed layer from the base material for the decorative sheet.
In the case of delamination between the surface layer and the core layer, unlike the case of delamination at the interface between the printed layer and the decorative sheet base material, the peel strength (adhesion strength) is less likely to decrease over time. Therefore, by inducing delamination between the surface layer and the core layer, the peel strength between the printed layer and the base material for the decorative sheet is suppressed over time. It becomes possible to easily separate the laminate containing the layer from the decorative sheet base material with a low peel force.

As a method for achieving the above easy peelability, the peak intensity ratio by IR spectroscopy of the surface layer of the substrate is less than 30 and the peak intensity ratio by Raman spectroscopy is less than 6.0, and the core of the substrate It is desirable that the layer has a peak intensity ratio of 43 or more by IR spectroscopy or a peak intensity ratio of 2.0 or more by Raman spectroscopy. The surface layer of the substrate has a peak intensity ratio of less than 30 by IR spectroscopy and a peak intensity ratio of less than 6.0 by Raman spectroscopy, and the core layer of the substrate has a peak intensity ratio of 43 or more by IR spectroscopy, or , By inducing delamination between the surface layer and the core layer by setting the peak intensity ratio by Raman spectroscopy to 2.0 or more, the laminate including the layers above the surface layer is separated from the decorative sheet base material. It can be easily peeled off and can be reused as a base material for decorative sheets.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows one structural example of the decorative sheet which concerns on embodiment of this invention.

An embodiment of the present invention will be described with reference to the drawings.
Here, the configuration shown in FIG. 1 is a schematic one, and the relation between the thickness and the planar dimension, the ratio of the thickness of each layer, and the like are different from the actual one. Further, the embodiments shown below are examples of configurations for embodying the technical idea of the present invention. It is not limited to things. Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

FIG. 1 is a cross-sectional view showing the configuration of a decorative sheet 1 according to this embodiment. The decorative sheet 1 has a base material 6 for a decorative sheet (hereinafter also referred to as base material 6) composed of a laminate including a plurality of thermoplastic resin layers, and on one side (surface) of the base material 6 In addition, a printed layer 5, an adhesive layer 4, a transparent resin layer 3 and a surface protective layer 2 are formed in this order. In addition, the decorative sheet 1 is provided with a masking layer 7 and a primer layer 8 on the other surface (back surface) of the base material 6 . The back surface of the base material 6 is also called the bottom surface.

The substrate 6 is composed of a laminate of n (n is any positive integer equal to or greater than 2) substrate layers. The base material 6 includes a first base material layer 6-1 (hereinafter referred to as the surface layer 6-1) which is the outermost surface, and a second base material layer 6-2 which is located below the surface layer 6-1. and at least one of the n-th base layers 6-n. The second base layer 6-2 to the (n-1)th base layer 6-(n-1) are "core layers 6-2 to 6-(n-1)", and the other base layer 6-(n-1) The n-th base layer 6-n, which is the surface, is also referred to as the "bottom layer 6-n". Further, when the substrate 6 is composed of two layers, the surface layer 6-1 and the core layer 6-2, the back surface of the core layer 6-2 is the other surface of the substrate 6. FIG.
Since the bottom layer 6-n may be in contact with the primer layer 8, it preferably has the same structure as the surface layer 6-1. By doing so, the adhesion between the base material 6 and the primer layer 8 can be maintained.

The concealing layer 7 may be formed between the base material 6 and the printed layer 5, or may be omitted. Especially in this embodiment, since the inorganic pigment is mixed in the base material 6 as will be described later, even if the masking layer 7 is omitted, there is no problem in terms of design. In order to reduce the amount of pigment mixed with the base material 6, it is preferable to provide the masking layer 7 as necessary.
The thickness of the decorative sheet 1 is preferably in the range of, for example, 49 μm or more and 360 μm or less. When the thickness of the decorative sheet 1 is within this range, the printing workability when manufacturing the decorative sheet 1 is improved, and the manufacturing cost can be suppressed.

Such a decorative sheet 1 constitutes a decorative board by attaching the surface (back surface) of the decorative sheet 1 on the side of the primer layer 8 to a base plate 9 made of, for example, a woody base material.
The easy peelability of the decorative sheet 1 is measured according to JIS K 6854-2. The decorative sheet 1 induces delamination between the surface layer 6-1 and the core layer 6-2 without deforming or tearing the substrate 6 in the peelability test between the transparent resin layer 3 and the substrate 6. It is preferable that the base material 6 and the layered product including the transparent resin layer 3 provided above the surface layer 6-1 can be separated by exfoliation.

Each part of the decorative sheet 1 will be described in detail below.
<Base material>
The substrate 6 of the present embodiment is made of a laminated stretched film thinned by uniaxial stretching or biaxial stretching.
By stretching the base material 6, the ratio of peak intensity by IR spectroscopy and the ratio of peak intensity by Raman spectroscopy are adjusted, and easy peelability is improved. The thickness of the base material 6 is preferably 20 μm or more and less than 60 μm, and more preferably 20 μm or more and 40 μm or less. When the thickness of the base material 6 is in the range of 20 μm or more and less than 60 μm, it is possible to make the decorative sheet 1 compatible with easy peelability, mechanical properties (mechanical strength), and noncombustibility. Moreover, when the thickness of the base material 6 is in the range of 20 μm or more and 40 μm or less, the nonflammability is further improved, which is more preferable.
It is considered that the reason why nonflammability is enhanced by setting the thickness of the base material 6 within the above numerical range is that the base material 6 is thinned by stretching. Further, the reason why the mechanical properties (mechanical strength) are enhanced by setting the thickness of the base material 6 within the above numerical range is considered to be that the base material 6 is toughened by stretching.

The noncombustibility of the base material 6 is evaluated by a heat generation test using a cone calorimeter tester conforming to ISO 5660-1 in a state where it is laminated with a noncombustible base material (not shown) made of a metal plate or an inorganic material. It is preferable to have incombustibility sufficient to satisfy the requirements described in Article 108-2, Item 1 and Item 2 of the Enforcement Order. It is possible to impart incombustibility sufficient to satisfy the requirements described in Article 108-2, Item 1 and Item 2 of the Enforcement Ordinance of the Building Standards Act, as in the examples described later.
As described above, the base material 6 is configured as a laminate of two or more base material layers, and the layers constituting each base material layer are formed of a resin material. The base material 6 contains polypropylene-based resin, which is a thermoplastic resin, as a main component of the resin material forming the base material layer. In this specification, the main component is, for example, 70 parts by mass or more and 100 parts by mass or less, preferably 90 parts by mass or more and 100 parts by mass or less of the resin material that constitutes the layer is 100 parts by mass. .

(Peak intensity ratio by IR spectroscopy of substrate 6)
The “peak intensity ratio by IR spectroscopy” in this embodiment will be described below.
When determining the peak intensity ratio by IR spectroscopy in the present embodiment, first, for example, using a PerkinElmer Fourier infrared spectrometer (Spectrum Spotlight 400), the absorption spectrum from 4000 cm ^-1 to 700 cm ^-1 is measured. do. Next, peak intensities at wavenumbers of 997 cm ⁻¹ , 973 cm ⁻¹ and 938 cm ⁻¹ are extracted from the obtained absorption spectrum, and the peak intensity ratio is calculated using the following formula (1). P998, P973 and P938 represent peak intensities at 998 cm ⁻¹ , 973 cm ⁻¹ and 938 cm ⁻¹ respectively. The crystallinity of the substrate 6 can be evaluated from the peak intensity ratio by IR spectroscopy.

(Peak intensity ratio by Raman spectroscopy of base material 6)
The “peak intensity ratio by Raman spectroscopy” in this embodiment will be described below.
In this embodiment, in order to measure the peak intensity ratio derived from the orientation of the polypropylene film surface by Raman spectroscopy, for example, using a microscopic Raman spectrometer (LabRAM ARAMIS) manufactured by Horiba, Ltd., 808 cm ^-1 , 841 cm ^- Measure each peak of ¹ . At that time, the Raman scattered light is analyzed using a polarizing filter. Here, the value of the peak intensity ratio is represented by the following equation (2).

^{The S808 parallel and the S841 parallel are the peak intensity at 808 cm −1 and the peak intensity at 841 cm −1 when} the polarization direction and the MD direction (flow direction during film formation) are parallel. S808 vertical is the peak intensity at 808 cm ⁻¹ when the polarization direction is perpendicular to the MD direction, and S841 vertical is the peak intensity at 841 cm ⁻¹ when the polarization direction is perpendicular to the MD direction. When polypropylene is used as the substrate 6, the peak of the crystalline portion of the resin is observed near 809 cm ⁻¹ and the peak of the amorphous portion of the resin is observed near 842 cm ⁻¹ . This peak intensity ratio serves as a measure of the degree of molecular orientation. That is, the molecular orientation can be evaluated from this peak intensity ratio.

[Surface layer]
The surface layer 6-1 has a peak intensity ratio of less than 30 as measured by IR spectroscopy and a peak intensity ratio of less than 6.0 as measured by Raman spectroscopy. By doing so, delamination between the surface layer 6-1 and the core layers 6-2 to 6-(n-1) is induced, and the substrate 6 and the laminate including the layers above the surface layer 6-1 are separated. can be easily peeled off.
If the peak intensity ratio of the surface layer 6-1 measured by IR spectroscopy is 30 or more, the interlayer adhesion strength derived from the crystallinity is improved, and sufficient easy peelability may not be imparted. Therefore, the peak intensity ratio of the surface layer 6-1 is set to less than 30 by IR spectroscopy. Further, when the peak intensity ratio of the surface layer 6-1 by Raman spectroscopy is 6.0 or more, the cohesive force derived from the orientation of the surface layer 6-1 is reduced, and sufficient easy peelability is maintained. Sometimes I can't. Therefore, the peak intensity ratio of the surface layer 6-1 measured by Raman spectroscopy is set to less than 6.0.

The peak intensity ratio of the surface layer 6-1 measured by IR spectroscopy is preferably 5 or more. If the peak intensity ratio of the surface layer 6-1 as measured by IR spectroscopy is less than 5, the mechanical strength of the laminated stretched film, that is, the substrate 6 may be lowered.
Also, the peak intensity ratio of the surface layer 6-1 by Raman spectroscopy is preferably 1.0 or more. If the peak intensity ratio of the surface layer 6-1 as measured by Raman spectroscopy is less than 1.0, the mechanical strength of the laminated stretched film, that is, the substrate 6 may decrease.

[Core layer]
The core layers 6-2 to 6-(n-1) preferably have a peak intensity ratio of 43 or more by IR spectroscopy or a peak intensity ratio of 2.0 or more by Raman spectroscopy. By doing so, the substrate 6 can obtain sufficient mechanical strength. Since the surface layer 6-1 has a relatively low peak intensity ratio (crystallinity) according to IR spectroscopy, the core layers 6-2 to 6-(n -1) preferably has a higher peak intensity ratio (crystallinity) by IR spectroscopy than the surface layer 6-1.

However, if the peak intensity ratio (crystallinity) of the core layers 6-2 to 6-(n-1) measured by IR spectroscopy is too high, the base material 6 may be torn at the time of peeling. Therefore, the peak intensity ratio of the core layers 6-2 to 6-(n-1) measured by IR spectroscopy is preferably 80 or less, more preferably 70 or less. Moreover, if the peak intensity ratio of the core layers 6-2 to 6-(n-1) measured by Raman spectroscopy is too high, the substrate 6 may be torn in the orientation direction. Therefore, the peak intensity ratio of the core layers 6-2 to 6-(n-1) measured by Raman spectroscopy should be 50.0 or less, preferably 15.0 or less, and more preferably 10.0 or less.

[Bottom layer]
The lowest layer 6-n may have a peak intensity ratio of less than 30 by IR spectroscopy and a peak intensity ratio of less than 6.0 by Raman spectroscopy. By doing so, the substrate 6 can obtain sufficient mechanical strength. The peak intensity ratio of the lowermost layer 6-n by IR spectroscopy is preferably 5 or more. If the lowermost layer 6-n has a peak intensity ratio of less than 5 as measured by IR spectroscopy, the mechanical strength of the laminated stretched film, that is, the substrate 6 may be lowered.
Also, the peak intensity ratio of the lowermost layer 6-n by Raman spectroscopy is preferably 1.0 or more. If the peak intensity ratio of the lowermost layer 6-n by Raman spectroscopy is less than 1.0, the mechanical strength of the laminated stretched film, that is, the substrate 6 may decrease.
From the viewpoint of mechanical strength, it is desirable that the layer ratio of the base material 6 to the total thickness is less than 30% for both the surface layer 6-1 and the bottom layer 6-n. If the layer ratio of each layer is 30% or more, sufficient mechanical strength may not be obtained.

As described above, by defining the peak intensity ratio by IR spectroscopy and/or the peak intensity ratio by Raman spectroscopy in each base material layer of the base material 6, easy peelability can be realized. In addition, in the present embodiment, since delamination is induced, delamination over time between the substrate 6 and the laminate including the transparent resin layer 3 provided above the surface layer 6-1 can be reduced. .

(resin material)
As described above, the main component of the resin material constituting each base material layer constituting the base material 6, that is, each base layer forming the surface layer 6-1 and the core layers 6-2 to 6-n is polypropylene-based. Resin.
Examples of polypropylene-based resins include those obtained by copolymerizing polypropylene with α-olefin alone or with two or more kinds thereof. Examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, tridecene, and 1-tetradecene. , 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4 -methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11 -methyl-1-dodecene, 12-ethyl-1-tetradecene and the like.
In order to improve the tensile modulus of the base material 6, it is preferable to use highly crystalline polypropylene.

(soft material)
Each substrate layer constituting the substrate 6 may contain a resin material with low crystallinity as a soft material in order to adjust the peak intensity ratio by IR spectroscopy and the peak intensity ratio by Raman spectroscopy after stretching. good.
Further, from the viewpoint of uniformity of the resin material forming each base material layer constituting the base material 6, the soft material is a material having high compatibility with the resin material forming each base material layer constituting the base material 6. Preferably. From this point of view, for example, when each base material layer constituting the base material 6 is made of a polypropylene-based resin, it is desirable that the soft material to be mixed is also a polypropylene-based resin.

In particular, the surface layer 6-1 desirably contains a resin material with low crystallinity in order to reduce the peak intensity ratio (crystallinity) by IR spectroscopy after stretching. Resin materials with low crystallinity that can be added to the surface layer 6-1 include, for example, (1) a polypropylene resin having a high ethylene content in the polypropylene main chain imparted by copolymerization of ethylene, and (2) an α-olefin of polypropylene. Polypropylene-based resins composed of a propylene-α-olefin copolymer that is a copolymer, (3) polypropylene-based resins having a lower melting point than isotactic homopolypropylene by lowering the stereoregularity of polypropylene-based resins, etc. be done.

The polypropylene resin containing a large amount of ethylene in the polypropylene main chain due to the copolymerization of ethylene described above preferably has an ethylene content of 4% or more, more preferably 15% or more.
Further, as the polypropylene-based resin composed of the above-mentioned propylene-α-olefin copolymer, for example, a polypropylene-based resin composed of a propylene-α-olefin copolymer having a copolymerization ratio of α-olefin of 16% or more is preferable. . If the copolymerization ratio is less than 16%, the cohesive force of the surface layer 6-1 is increased, and there is a possibility that sufficient easy peelability cannot be obtained.

As the polypropylene-based resin with lowered stereoregularity, for example, one having a mesopentat fraction of less than 45% is preferable. If the mesopentat fraction is 45% or more, the peak intensity ratio (crystallinity) by IR spectroscopy increases, the cohesive force of the surface layer 6-1 improves, and there is a possibility that sufficient easy peelability cannot be obtained. be.
By appropriately blending such a softening agent, it is possible to adjust the peak intensity ratio by IR spectroscopy and the peak intensity ratio by Raman spectroscopy of the stretched surface layer 6-1. As for the blending amount, the soft material is preferably mixed in an amount of 5 to 80 parts by weight, more preferably 60 to 80 parts by weight, with respect to the main component resin (base resin).

(Inorganic pigment)
At least one base material layer constituting the base material 6 preferably contains an inorganic pigment. By containing the inorganic pigment, the light transmittance of the base material 6 is lowered so that the pattern of the base plate 9 to which the decorative sheet 1 is adhered can be prevented from being transmitted.
The mixing amount of the inorganic pigment is preferably 5 vol % or more and 50 vol % or less with respect to the resin material in the base layer containing the inorganic pigment. When the mixing amount of the inorganic pigment is 5 vol% or more and 50 vol% or less, the effect of improving the nonflammability due to the addition of the inorganic pigment is exhibited, and embrittlement of the base material 6 due to the addition amount of the inorganic pigment being too large is also suppressed. This is because

The inorganic pigment to be contained is not particularly limited, but examples thereof include natural inorganic pigments and synthetic inorganic pigments.
Examples of natural inorganic pigments include earth pigments, calcined earth, and mineral pigments. Examples of synthetic inorganic pigments include oxide pigments, hydroxide pigments, sulfide pigments, silicate pigments, phosphate pigments, carbonate pigments, metal powder pigments, and carbon pigments. Also, one or a mixture of two or more of natural inorganic pigments and synthetic inorganic pigments may be used.
In addition, it is not preferable to use an organic pigment as the pigment. This is because the nonflammability of the substrate 6 is impaired.

The base material 6 preferably has a light transmittance of 40% or less in order to obtain the concealing property required from the viewpoint of the design of the decorative sheet 1 . If the light transmittance is more than 40%, the decorative sheet 1 cannot have sufficient concealing properties to bring out the design. In addition, the above-mentioned "sufficient hiding property cannot be obtained" means, for example, in a decorative board configured by attaching the surface of the decorative sheet 1 on the primer layer 8 side to a base board 9 made of a wooden base material or the like. , means that the pattern on the surface of the wood substrate or the like facing the primer layer 8 is visible from the side of the surface protective layer 2 through the decorative sheet 1 . When visible in this way, the design of the printed layer 5 and the pattern of the substrate plate 9 such as a wooden substrate may be visually recognized overlapping. It is preferable to provide the concealing layer 7 when it is visible.

<Print layer>
The printed layer 5 is a layer on which a pattern is formed in order to impart design properties. The printed layer 5 can be provided on the surface layer 6-1 of the substrate 6 using a known printing technique. If the substrate 6 can be prepared in a rolled state, printing for forming the printing layer 5 can be performed by a roll-to-roll printing apparatus. The printing method is not particularly limited, but if productivity and image quality are taken into consideration, gravure printing, for example, can be used.

As for the pattern, any pattern may be adopted in consideration of the design properties according to the place of use such as the floor material and the wall material. For example, when obtaining a decorative sheet 1 having a wood-based pattern, various wood grain patterns are often preferred for the pattern, and a cork pattern may be used in addition to the wood grain pattern. In addition, when obtaining the decorative sheet 1 having an image of a stone floor such as marble, the grain of marble or the like is used for the picture pattern. In addition to the picture patterns of natural materials, artificial picture patterns such as geometric patterns and artificial patterns using natural materials as motifs are used as the picture patterns of the printed layer 5 .

The printing ink used to form the printing layer 5 is not particularly limited, but an ink corresponding to the printing method is appropriately selected. In particular, it is preferable to select the printing ink in consideration of adhesion to the substrate 6, printability, weather resistance of the decorative sheet 1, and the like.
Coloring agents such as pigments and dyes, extender pigments, solvents, and binders, which are contained in ordinary inks, are appropriately added to the printing ink. Examples of pigments include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, and pearl pigments such as mica. The binder may be water-based, solvent-based, or emulsion type, and the curing method is also particularly limited, such as a one-liquid type, a two-liquid type consisting of a main agent and a curing agent, or a type that is cured by ultraviolet rays, electron beams, or the like. not something to do. Among them, the general method is a two-liquid type method using a urethane-based main agent and a curing agent composed of isocyanate. In addition, the design may be applied by vapor deposition or sputtering of various metals.
The thickness of the printed layer 5 is preferably 2 μm or more and 20 μm or less. When the thickness of the printed layer 5 is within this range, the print can be clearly printed, the printing workability in manufacturing the decorative sheet 1 can be improved, and the manufacturing cost can be suppressed.

<Adhesive layer>
The adhesive layer 4 is provided for the purpose of strengthening the adhesion between the base material 6 and the printed layer 5 and the transparent resin layer 3 . Strong adhesion between the base material 6 and the printed layer 5 and the transparent resin layer 3 makes it possible to give the decorative sheet 1 bending workability to follow curved surfaces and perpendicular surfaces. Adhesive layer 4 is preferably transparent.
The adhesive layer 4 is made of, for example, an acrylic adhesive, a polyester adhesive, a polyurethane adhesive, an epoxy adhesive, or the like. As the adhesive constituting the adhesive layer 4, it is usually preferable to use a urethane-based material obtained by reaction with a polyol using isocyanate as a two-liquid curing type because of its cohesion. Note that the adhesive layer 4 may be omitted if sufficient adhesive strength is obtained between the transparent resin layer 3 and the printed layer 5 .

Any method can be selected as a method for bonding the substrate 6 and the printed layer 5 to the transparent resin layer 3 via the adhesive layer 4. For example, a lamination method such as thermal lamination, extrusion lamination, or dry lamination can be used. mentioned.
The thickness of the adhesive layer 4 is preferably 1 μm or more and 20 μm or less. When the thickness of the adhesive layer 4 is within this range, the adhesive strength between the base material 6 and the printed layer 5 and the transparent resin layer 3 is improved, and the printing workability during the production of the decorative sheet 1 is improved. , and the manufacturing cost can be suppressed.

<Transparent resin layer>
The transparent resin layer 3 is composed of, for example, a transparent resin sheet, and is adhered to the base material 6 and the printed layer 5 with an adhesive layer 4 . In the decorative sheet 1 shown in FIG. 1, the case where the transparent resin layer 3 is one layer is illustrated, but a plurality of transparent resin layers 3 may be laminated. The transparent resin layer 3 of this embodiment is preferably composed mainly of a polyolefin resin. The main component is, for example, 70 to 100 parts by mass, preferably 90 to 100 parts by mass of the resin material that constitutes the transparent resin layer 3 is 100 parts by mass.

Examples of polyolefin-based resins constituting the transparent resin layer 3 include polypropylene, polyethylene, polybutene, and α-olefins (eg, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1- Octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3- methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-pentene, 4- ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc.) homopolymerized or copolymerized with two or more Monoya, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-butyl methacrylate copolymer, ethylene-methyl acrylate copolymer , ethylene/ethyl acrylate copolymer, ethylene/butyl acrylate copolymer, and the like, copolymers of ethylene or α-olefin with other monomers. In order to improve the surface strength of the decorative sheet 1, it is preferable to use highly crystalline polypropylene.
The thickness of the transparent resin layer 3 is preferably 20 μm or more and 200 μm or less. When the thickness of the transparent resin layer 3 is within this range, the strength of the decorative sheet 1 is improved, the printing workability in manufacturing the decorative sheet 1 is improved, and the manufacturing cost can be suppressed.

<Surface protective layer>
The surface protective layer 2 is provided on the outermost surface of the decorative sheet 1 and has functions of surface protection and gloss adjustment. Materials constituting the surface protective layer 2 include, for example, polyurethane-based resins, acrylic silicon-based resins, fluorine-based resins, epoxy-based resins, vinyl-based resins, polyester-based resins, melamine-based resins, aminoalkyd-based resins, and urea-based resins. etc. The form of the resin material is not particularly limited, and may be water-based, emulsion, solvent-based, or the like. As for the curing method, a one-liquid type, a two-liquid type, an ultraviolet curing method, or the like can be selected as appropriate.

In particular, as the resin material that is the main component of the surface protective layer 2, a urethane-based resin using isocyanate is suitable from the viewpoints of workability, cost, cohesion of the resin itself, and the like. Isocyanates include, for example, tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), diphenylmethane diisocyanate (MDI), lysine diisocyanate (LDI), isophorone diisocyanate (IPDI), methylhexane diisocyanate (HTDI). ), methylcyclohexanone diisocyanate (HXDI), trimethylhexamethylene diisocyanate (TMDI), and the like. Among them, hexamethylene diisocyanate (HMDI) having a linear molecular structure is suitable as the isocyanate from the viewpoint of weather resistance. In addition, in order to improve the surface hardness, it is preferable to use a resin that is cured by active energy rays such as ultraviolet rays and electron beams. These resins can be used in combination with each other. For example, by using a hybrid type of thermosetting type and photosetting type, it is possible to improve surface hardness, suppress curing shrinkage, and improve adhesion. can be planned.
The thickness of the surface protective layer 2 is preferably 3 μm or more and 20 μm or less. When the thickness of the surface protective layer 2 is within this range, it is possible to protect the surface of the decorative sheet 1 and to provide sufficient luster, improve the printing workability when manufacturing the decorative sheet 1, and reduce the manufacturing cost. can be suppressed.

<Concealing layer>
The concealing layer 7 is formed for the purpose of maintaining the concealability with respect to the base plate 9 in the decorative plate in which the surface of the decorative sheet 1 on the primer layer 8 side is attached to the base plate 9 such as a wooden base. be. The masking layer 7 is formed, for example, by ink printing in the same manner as the printed layer 5 . As the pigment to be included in the ink, it is preferable to use, for example, an opaque pigment, titanium oxide, iron oxide, or the like. In addition, in order to improve the concealability of the pattern of the base plate 9 made of a wooden base material or the like to which the decorative sheet 1 is attached in the concealing layer 7, for example, a metal such as gold, silver, copper, or aluminum is added to the ink. It is also possible to add aluminum flakes, and it is generally preferable to add aluminum flakes. As described above, the concealing layer 7 can be omitted when any one of the substrate layers of the substrate 6 is opaque and has concealing properties.
The thickness of the concealing layer 7 is preferably 2 μm or more and 20 μm or less. When the thickness of the concealing layer 7 is within this range, it is possible to maintain the concealability with respect to the base plate 9, improve printing workability when manufacturing the decorative sheet 1, and reduce manufacturing costs.

<Primer layer>
The primer layer 8 is provided to improve adhesion between the decorative sheet 1 and the base plate 9 in the decorative plate in which the primer layer 8 side of the decorative sheet 1 is attached to the base plate 9 .
The primer layer 8 can basically use the same material (printing ink) as the printing layer 5 . In particular, considering that the decorative sheet 1 is wound in a web shape because it is applied to the back surface, inorganic fillers such as silica, alumina, magnesia, titanium oxide, and barium sulfate are added to the printing ink. It is preferable to add This makes it possible to avoid the occurrence of blocking when the decorative sheet 1 is wound up, and to enhance the close contact with the adhesive.

When the substrate plate 9 is a wood substrate, the primer layer 8 is made of, for example, an ester resin, a urethane resin, an acrylic resin, a polycarbonate resin, a vinyl chloride-vinyl acetate copolymer, a polyvinyl butyral resin, It is preferably made of a resin material such as nitrocellulose resin. These resin materials can be used alone or mixed to form an adhesive composition, which can be formed using an appropriate coating means such as a roll coating method or a gravure printing method. In this case, it is preferable to use a urethane-acrylate resin as the resin material forming the primer layer 8 . That is, it is particularly preferable to use a resin composed of a copolymer of an acrylic resin and a urethane resin and an isocyanate.

The thickness of the primer layer 8 is preferably 0.1 μm or more and 20 μm or less. When the thickness of the primer layer 8 is within this range, the adhesiveness between the decorative sheet 1 and the base plate 9 is improved, and the printing workability when manufacturing the decorative sheet 1 is improved. Cost can be suppressed. Furthermore, when the bottom layer 6-n of the base material 6 has the same material and structure as the surface layer 6-1, the interlayer adhesion between the base material 6 and the primer layer 8 can be improved. Adhesion with the base plate 9 can be improved.

The decorative sheet 1 using the base material 6 according to the present embodiment uses a base material formed by stretching and thinning a resin film mainly composed of polypropylene-based resin, which is a thermoplastic resin, so that the base material 6 In addition, separation from the base material 6 and its laminate over time is reduced while providing easy peelability from the laminate including the transparent resin layer 3 and the like provided above the surface layer 6-1.
In addition, the decorative sheet 1 according to the present embodiment has multiple layers of polypropylene-based resin constituting the stretched film, and the surface layer 6-1 has a peak intensity ratio of less than 30 by IR spectroscopy and a peak by Raman spectroscopy. The intensity ratio is less than 6.0, and the peak intensity ratio of the core layers 6-2 to 6-(n-1) is 43 or more by IR spectroscopy, or 2.0 or more by Raman spectroscopy.

According to this configuration, in the present embodiment, it is possible to induce delamination inside the base material 6, so that the base material 6 and the transparent resin layer 3 provided above the surface layer 6-1 are separated. It is possible to reduce delamination over time between the base material 6 and the laminate while providing easy peelability from the laminate containing the base material 6 .
That is, according to the present embodiment, the base material 6 and the laminate including the transparent resin layer 3 provided above the surface layer 6-1 are easily separated from each other, and the base material 6 and the laminate thereof are easily peeled off. It is possible to obtain the decorative sheet 1 with reduced peeling over time.

Furthermore, since the base material 6 can be thinned by stretching, it is also possible to improve nonflammability.
Here, when the base material 6 is composed of three or more base material layers, that is, when the core layers 6-2 to 6-n are two or more layers, the lowest layer (nth layer) 6-n is , is preferably made of the same material as the surface layer 6-1. That is, the lowest layer (n-th layer) 6-n preferably has a peak intensity ratio of less than 30 by IR spectroscopy and less than 6.0 by Raman spectroscopy.
With this configuration, it is possible to impart sufficient mechanical strength to the substrate 6 .

[Example]
The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.
<Example 1>
First, Example 1 will be described.
The decorative sheet of Example 1 was formed by the steps shown below.
(Step of forming resin sheet for transparent resin layer)
First, a resin material was prepared by adding a hindered phenol-based antioxidant, a benzotriazole-based ultraviolet absorber, and a hindered amine-based light stabilizer to a homopolypropylene resin. Here, as the homopolypropylene resin, a material having a mesopentad fraction of 97.8%, an MFR (melt flow rate) of 15 g/10 min (230° C.), and a molecular weight distribution MWD (Mw/Mn) of 2.3 is used. bottom. A hindered phenol-based antioxidant (Irganox 1010: manufactured by BASF) was added at 500 ppm to the homopolypropylene resin. A benzotriazole-based ultraviolet absorber (TINUVIN 328: manufactured by BASF) was added at 2000 PPM to the homopolypropylene resin. A hindered amine light stabilizer (Kimasorb 944: manufactured by BASF) was added at 2000 PPM to the homopolypropylene resin. Such a resin material was extruded using a melt extruder to form a polypropylene transparent resin sheet having a thickness of 80 μm to be used as a transparent resin layer.
Subsequently, both surfaces of the obtained transparent resin sheet were subjected to corona treatment to adjust the wetting tension of the surface of the transparent resin sheet to 40 dyn/cm or more.

(Step of forming base material)
A structure in which the substrate 6 is composed of three substrate layers, the first layer being the surface layer 6-1, the second layer being the core layer 6-2, and the third layer being the bottom layer 6-3. A laminated stretched film was adopted. Then, a base material 6 for decorative sheet was formed by extruding and stretching the base material in which three layers of the first to third layers were laminated using a polypropylene-based resin.
A layer serving as a precursor of the surface layer 6-1 of the first layer was formed with a thickness of 20 μm using the following resin A as a material. Subsequently, a layer that will be the precursor of the core layer 6-2 that is the second layer is formed on the layer that will be the precursor of the surface layer 6-1 of the first layer, and the following resin B to which an inorganic pigment is added is added. It was formed with a thickness of 108 μm using this material. On top of this, a layer to be the precursor of the lowermost layer 6-3 of the third layer was formed with a thickness of 20 μm using the following resin E as a material.
Thereby, a laminated resin precursor having a total thickness of 148 μm of three layers was formed.
Subsequently, this laminated resin precursor was stretched 4 times by a uniaxial stretching method to obtain a base material having a thickness of 37 μm (surface layer 6-1 film thickness 5 μm, core layer 6-2 film thickness 27 μm, maximum A lower layer 6-3 having a film thickness of 5 μm) was formed.

[Resin A]
Resin material: Resin containing 80 parts by mass of low-crystalline polypropylene resin having an ethylene content of 16% and 20 parts by mass of random polypropylene [Resin B]
Resin material: Homo PP (polypropylene) with a mesopentad fraction of 85%
[Resin E]
Resin material: Homo PP

(Step of forming printed layer and primer layer)
A printed layer 5 was formed on the surface layer 6-1 of the base material 6 by printing a pattern by gravure printing. The printing layer 5 is a two-component urethane ink (V180; manufactured by Toyo Ink Mfg. Co., Ltd.), and 0.5 mass of a hindered amine-based light stabilizer (Kimasorb 944; manufactured by BASF) with respect to the binder resin content of the ink. % added ink.
Also, a primer layer 8 was formed on the back surface of the bottom layer 6-3 of the substrate 6. As shown in FIG. The primer layer 8 was formed by printing a two-component urethane ink similar to that for the printed layer 5 by gravure printing.

(Step of forming transparent resin layer)
Subsequently, an adhesive for dry lamination (Takelac A540; manufactured by Mitsui Chemicals, Inc.; coating amount: 2 g/m ² ) is applied as the adhesive layer 4 to the surface layer 6-1 side of the substrate 6 on which the printed layer 5 is formed. bottom. Thereafter, the transparent resin layer 3 was formed by laminating a transparent resin sheet to the front surface of the base material 6 on which the printed layer 5 was formed via the adhesive layer 4 by a dry lamination method. Also, the surface of the transparent resin layer 3 was embossed.

(Step of forming surface protective layer)
A two-component curable urethane top coat (W184; manufactured by DIC Graphics Co., Ltd.) is applied to the surface of the embossed transparent resin layer 3 at a coating thickness of 6 g/m ² and dried to form the surface protective layer 2 . formed.
Thus, a decorative sheet 1 of Example 1 having a total thickness of 132 μm was obtained.
In Example 1, the surface layer 6-1 has a peak intensity ratio of 27 in IR spectroscopy and a peak intensity ratio of 2.2 in Raman spectroscopy, and the core layer 6-2 has a peak intensity of 2.2 in IR spectroscopy. The ratio is 50 and the peak intensity ratio in Raman spectroscopy is 5.1, and the lowest layer 6-3 has a peak intensity ratio in IR spectroscopy of 40 and a peak intensity ratio in Raman spectroscopy of 7.0. rice field.

<Example 2>
A decorative sheet 1 constituting Example 2 was obtained in the same manner as in Example 1, except that the following resin C material was used as the material for the bottom layer 6-3.
[Resin C]
Resin material: random PP (4% ethylene content)
In Example 2, the surface layer 6-1 has a peak intensity ratio of 27 in IR spectroscopy and a peak intensity ratio of 2.2 in Raman spectroscopy, and the core layer 6-2 has a peak intensity of 2.2 in IR spectroscopy. The ratio is 50 and the peak intensity ratio in Raman spectroscopy is 5.1, and the lowest layer 6-3 has a peak intensity ratio in IR spectroscopy of 40 and a peak intensity ratio in Raman spectroscopy of 4.5. rice field.

<Example 3>
A decorative sheet 1 constituting Example 3 was obtained in the same manner as in Example 1, except that the material of resin A was used as the material of the lowermost layer 6-3.
In Example 3, the surface layer 6-1 has a peak intensity ratio of 27 in IR spectroscopy and a peak intensity ratio of 2.2 in Raman spectroscopy, and the core layer 6-2 has a peak intensity of 2.2 in IR spectroscopy. The ratio is 50 and the peak intensity ratio in Raman spectroscopy is 5.1, and the lowest layer 6-3 has a peak intensity ratio in IR spectroscopy of 27 and a peak intensity ratio in Raman spectroscopy of 2.2. rice field.

<Example 4>
A decorative sheet 1 constituting Example 4 was formed in the same manner as in Example 2, except that the following resin D material was used as the material for the core layer 6-2.
[Resin D]
Resin material: Resin containing 80 parts by mass of low-crystalline polypropylene resin having an ethylene content of 4% and 20 parts by mass of random polypropylene In Example 4, the surface layer 6-1 had a peak intensity ratio of 27 in IR spectroscopy, The peak intensity ratio in Raman spectroscopy is 2.2, the core layer 6-2 has a peak intensity ratio in IR spectroscopy of 38, and a peak intensity ratio in Raman spectroscopy is 2.4. -3 had a peak intensity ratio of 40 by IR spectroscopy and a peak intensity ratio of 4.5 by Raman spectroscopy.

<Example 5>
A decorative sheet 1 constituting Example 5 was formed in the same manner as in Example 3, except that the resin D material was used as the material for the core layer 6-2.
In Example 5, the surface layer 6-1 has a peak intensity ratio of 27 in IR spectroscopy and a peak intensity ratio of 2.2 in Raman spectroscopy, and the core layer 6-2 has a peak intensity of 2.2 in IR spectroscopy. The ratio is 38 and the peak intensity ratio in Raman spectroscopy is 2.4, and the lowest layer 6-3 has a peak intensity ratio in IR spectroscopy of 27 and a peak intensity ratio in Raman spectroscopy of 2.2. rice field.

<Comparative Example 1>
As the materials for the surface layer 6-1, the core layer 6-2, and the bottom layer 6-3, a laminated resin precursor was formed using the material of the above resin B, but the laminated resin precursor was not stretched. . Thus, the decorative sheet 1 of Comparative Example 1 was obtained. The thickness of the surface layer 6-1 was 5 μm, the thickness of the core layer 6-2 was 27 μm, and the thickness of the lowermost layer 6-3 was 5 μm.
In Comparative Example 1, the surface layer 6-1 has a peak intensity ratio of 53 in IR spectroscopy and a peak intensity ratio of 1.2 in Raman spectroscopy, and the core layer 6-2 has a peak intensity in IR spectroscopy. The ratio is 52 and the peak intensity ratio in Raman spectroscopy is 1.2, and the lowest layer 6-3 has a peak intensity ratio in IR spectroscopy of 53 and a peak intensity ratio in Raman spectroscopy of 1.2. rice field.

<Comparative Example 2>
Comparative Example 2 was prepared in the same manner as in Comparative Example 1 except that the thickness of the surface layer 6-1 was 8 μm, the thickness of the core layer 6-2 was 72 μm, and the thickness of the bottom layer 6-3 was 8 μm. A decorative sheet 1 was formed.
In Comparative Example 2, the surface layer 6-1 has a peak intensity ratio of 52 in IR spectroscopy and a peak intensity ratio of 1.4 in Raman spectroscopy, and the core layer 6-2 has a peak intensity in IR spectroscopy. The ratio is 53 and the peak intensity ratio in Raman spectroscopy is 1.1, and the lowest layer 6-3 has a peak intensity ratio in IR spectroscopy of 52 and a peak intensity ratio in Raman spectroscopy of 1.4. rice field.

<Comparative Example 3>
The above resin C material is used as the material for the surface layer 6-1, the above resin D material is used as the material for the core layer 6-2, and the above resin C material is used as the material for the bottom layer 6-3. A decorative sheet 1 constituting Comparative Example 3 was formed in the same manner as in Example 1 except that the materials were used.
In Comparative Example 3, the surface layer 6-1 has a peak intensity ratio of 40 in IR spectroscopy and a peak intensity ratio of 4.5 in Raman spectroscopy, and the core layer 6-2 has a peak intensity in IR spectroscopy. The ratio is 38, the peak intensity ratio in Raman spectroscopy is 2.4, and the lowest layer 6-3 has a peak intensity ratio in IR spectroscopy of 40, and a peak intensity ratio in Raman spectroscopy of 4.5. rice field.

<Comparative Example 4>
A decorative sheet 1 constituting Comparative Example 4 was formed in the same manner as in Comparative Example 3, except that the resin B material was used as the material of the core layer 6-2.
In Comparative Example 4, the surface layer 6-1 has a peak intensity ratio of 40 in IR spectroscopy and a peak intensity ratio of 4.5 in Raman spectroscopy, and the core layer 6-2 has a peak intensity in IR spectroscopy. The ratio is 50 and the peak intensity ratio in Raman spectroscopy is 5.1, and the lowest layer 6-3 has a peak intensity ratio in IR spectroscopy of 40 and a peak intensity ratio in Raman spectroscopy of 4.5. rice field.
Table 1 shows the configuration of each example and each comparative example. Table 1 also describes the evaluation.

(Peak intensity ratio by IR spectroscopy of substrate 6)
In each example and each comparative example, when obtaining the peak intensity ratio by IR spectroscopy, an absorption spectrum from 4000 cm ^-1 to 700 cm ^-1 was measured using a Perkin Elmer Fourier infrared spectrometer (Spectrum Spotlight 400). It was measured. Next, peak intensities at wavenumbers of 997 cm ⁻¹ , 973 cm ⁻¹ and 938 cm ⁻¹ were extracted from the obtained absorption spectrum, and the peak intensity ratio was calculated using the following formula (3). P998, P973, and P938 represent peak intensities at 998 cm ⁻¹ , 973 cm ⁻¹ , and 938 cm ⁻¹ , respectively.

<Method for measuring peak intensity ratio in Raman spectroscopy>
In each example and each comparative example, the peak intensity ratio derived from the orientation of the polypropylene film surface was measured by Raman spectroscopy. Specifically, peaks at 808 cm ⁻¹ and 841 cm ⁻¹ were measured using a microscopic Raman spectrometer (LabRAM ARAMIS) manufactured by Horiba, Ltd. At that time, the Raman scattering light was analyzed using a polarizing filter. Here, the value of the peak intensity ratio is represented by the following equation (4).

The S808 parallel and the S841 parallel were defined as the peak intensity at 808 cm ⁻¹ and the peak intensity at 841 cm ⁻¹ when the polarization direction and the MD direction (flow direction during film formation) were parallel. The S808 vertical is the peak intensity at 808 cm ⁻¹ when the polarization direction is perpendicular to the MD direction, and the S841 vertical is the peak intensity at 841 cm ⁻¹ when the polarization direction is perpendicular to the MD direction.

<Performance evaluation of decorative sheet>
Performance evaluation was performed on the decorative sheets of each example and each comparative example.

[Evaluation of easy peelability by peelability test (180 degree peel test)]
The peelability test is a test for evaluating adhesion (adhesion) between the transparent resin layer and the substrate as peel strength. A peelability test was performed according to JIS K 6854-2 using the decorative sheets of each example and each comparative example.
Evaluation is as follows.
⊚: Very good (within standard) (no printed layer remained on base material for decorative sheet after peeling, peel force less than 3 N/inch)
◯: Good (within standard) (no printed layer remained on base material for decorative sheet after peeling, peel force of 3 N/inch or more and less than 20 N/inch)
Δ: Acceptable (within the standard) (no printed layer remained on the base material for decorative sheet after peeling, peeling force of 20 N/inch or more and less than 30 N/inch)
×: Poor (non-standard) (printed layer remains on base material for decorative sheet after peeling)

[Presence or absence of substrate deformation during peelability test (180 degree peel test)]
The presence or absence of deformation of the base material and the degree of deformation during deformation were evaluated when the peelability test (180 degree peel test) was conducted.
Evaluation is as follows.
◎: Very good (within the standard) (no deformation such as fluffing, tearing, tearing, etc., spreading on the decorative sheet base material after peeling)
◯: Good (within standard) (Fuzz, elongation, and wrinkles in base material for decorative sheet after peeling, but no tearing or tearing)
△: Slightly deteriorated (the base material for decorative sheet after peeling has fluffing, elongation, wrinkles, and tears, but no tears)
×: Poor (the decorative sheet base material after peeling has fuzz, elongation, wrinkles, tears, and tears)

[Evaluation of mechanical strength by elastic modulus measurement (tensile test)]
The decorative sheet of each example and each comparative example was pulled at 50 mm/min by a Tensilon universal material testing machine to measure the elastic modulus.
Evaluation of elastic modulus is as follows.
○: Very good (elastic modulus of 800 MPa or more)
△: good (modulus of elasticity of 500 MPa or more and less than 800 MPa)
×: Poor (elastic modulus less than 500 MPa)

[Evaluation of noncombustibility by noncombustibility test]
Using the decorative sheet of each sample, a heat build-up test was conducted using a cone calorimeter tester conforming to ISO5560-1. Noncombustibility was determined by whether or not the provisions of Article 108-2, Item 1 and Item 2 of the Enforcement Ordinance of the Building Standards Law were satisfied.
Evaluation is as follows.
○: Good (within standard)
×: Defective (non-standard)

As can be seen from the results of the peelability test (easy peelability) shown in Table 1, in the decorative sheets of Examples 1 to 5, due to deterioration over time, the base material and the transparent resin layer provided above the surface layer There was no peeling from the laminate containing such as.
Further, as can be seen from the test results of the elastic modulus shown in Table 1, in the decorative sheets of Examples 1 to 5, delamination was induced inside the base material, and the transparent resin layer was easily removed from the base material together with the printed layer. can be peeled off.

1 decorative sheet 2 surface protective layer 3 transparent resin layer 4 adhesive layer 5 printed layer 6 substrate 6-1 surface layer (surface substrate layer)
6-2 to 6-n Core layer 7 Concealing layer 8 Primer layer 9 Base plate

Claims (4)

A base material for a decorative sheet , which is a uniaxial laminated stretched film and has a plurality of layers in which the main component of the resin material is a polypropylene-based resin;
one or more transparent resin layers containing a polypropylene-based resin formed on the surface of the decorative sheet base material on the surface layer side;
Having a printed layer provided between the decorative sheet base material and the transparent resin layer ,
Among the plurality of layers, the first layer located on the outermost surface is defined as the surface layer, the layer located on the backmost surface is defined as the bottom layer, and the layers other than the surface layer and the bottom layer among the multiple layers is defined as the core layer,
The surface layer has a peak intensity ratio of more than 0 and less than 30 by IR spectroscopy and a peak intensity ratio of more than 0 to less than 6.0 by Raman spectroscopy,
The decorative sheet , wherein the core layer has a peak intensity ratio of 43 or more as determined by IR spectroscopy for the entire core layer . The lower layer of the core layer has the lowermost layer whose main component of the resin material is a polypropylene resin,
2. The decorative sheet according to claim 1, wherein the lowermost layer has a peak intensity ratio of more than 0 to less than 30 by IR spectroscopy and a peak intensity ratio of more than 0 to less than 6.0 by Raman spectroscopy. The base material for the decorative sheet was subjected to a heat generation test by a cone calorimeter tester conforming to ISO 5660-1 in a state where it was laminated with a nonflammable base material. 3. The decorative sheet according to claim 1 or 2, wherein the decorative sheet is a noncombustible material that satisfies the requirements of item 2 . A decorative board comprising the decorative sheet according to any one of claims 1 to 3 and a base board made of a wood material.

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