JP2021151766A - Decorative sheet and decorative material - Google Patents

Abstract

To provide a decorative sheet and a decorative material that have excellent scratch resistance and impact resistance, suppress cracking during bending, have excellent impact resistance under cold temperatures, and suppress cracking during bending even under cold temperatures.SOLUTION: There is provided a decorative sheet with a transparent resin layer at least under a surface protective layer, in which (1) the transparent resin layer has a first transparent resin layer and a second transparent resin layer in an order from the surface protective layer side, (2) the first transparent resin layer has a thickness of 10 μm or more and less than 20 μm, and an indentation hardness of 80 MPa or more, (3) the second transparent resin layer has a thickness of 35 μm or more and an indentation hardness of 40 MPa or more and 70 MPa or less, (4) the first transparent resin layer and the second transparent resin layer contain a polypropylene resin, and (5) a total of the thickness of the first transparent resin layer and the thickness of the second transparent resin layer is 60 μm or more.SELECTED DRAWING: None

Description

The present invention relates to a decorative sheet and a decorative material.

Conventionally, in order to improve the scratch resistance of a decorative sheet, a method of applying an ionizing radiation curable resin to a surface protective layer and curing it has been used. Decorative sheets used for floor decorative materials and the like are required to have even higher scratch resistance and impact resistance.

If a soft resin is used for the surface protective layer in order to improve the impact resistance of the decorative sheet, there is a problem that the scratch resistance is lowered. On the other hand, in order to further improve the scratch resistance, a method of increasing the thickness of the surface protective layer to improve the hardness is known. However, if the surface protective layer is made too thick and too hard, there is a problem that the coating film is easily cracked by falling objects and the like, and the impact resistance is lowered. In particular, when used in a cold region, there is a problem that the decorative sheet becomes hard under cold temperature and the impact resistance is further lowered.

In addition, although scratch resistance is improved by thickening the surface protective layer and hardening the transparent resin layer, there is a problem that the decorative sheet breaks (cracks) during bending, and in particular, processing in a cold environment. There is a problem that it is sometimes easily broken (cracked).

As a decorative sheet with improved scratch resistance and scratch resistance, a transparent polypropylene resin showing a specific range of thickness and hardness and a decorative sheet for flooring having a transparent surface protective layer showing a specific range of hardness are available. It has been proposed (see, for example, Patent Document 1).

The above-mentioned decorative sheet for flooring is also an excellent decorative sheet, but cracking during bending has not been examined, and there is room for improvement. Therefore, it is excellent in scratch resistance and impact resistance required for a decorative sheet, and cracks during bending are suppressed. In particular, it is excellent in impact resistance under cold temperature and is bent even at cold temperature. It is desired to develop a decorative sheet in which time cracking is suppressed.

Japanese Unexamined Patent Publication No. 2006-1235112

The present invention is excellent in scratch resistance and impact resistance, and cracks during bending are suppressed, and is excellent in impact resistance under cold temperature, and cracks during bending are suppressed even under cold temperature. It is an object of the present invention to provide a decorative sheet and a decorative material.

As a result of diligent research, the present inventors have conducted, and as a result, at least in a decorative sheet having a transparent resin layer under the surface protective layer, the transparent resin layer is the first transparent resin layer and the first transparent resin layer in order from the surface protective layer side. It has two transparent resin layers, and the first transparent resin layer and the second transparent resin layer each exhibit a specific range of layer thickness and indentation hardness, and the first transparent resin layer and the second transparent resin layer are transparent. According to the decorative sheet in which the sex resin layer contains a polypropylene-based resin and the total of the layer thickness of the first transparent resin layer and the layer thickness of the second transparent resin layer is in a specific range, the above object can be achieved. The present invention has been completed.

That is, the present invention relates to the following decorative sheet.
1. 1. A decorative sheet having at least a transparent resin layer under the surface protective layer.
(1) The transparent resin layer has a first transparent resin layer and a second transparent resin layer in order from the surface protection layer side.
(2) The first transparent resin layer has a thickness of 10 μm or more and less than 20 μm, and an indentation hardness of 80 MPa or more.
(3) The second transparent resin layer has a thickness of 35 μm or more and an indentation hardness of 40 MPa or more and 70 MPa or less.
(4) The first transparent resin layer and the second transparent resin layer contain a polypropylene resin and contain a polypropylene resin.
(5) The total thickness of the first transparent resin layer and the thickness of the second transparent resin layer is 60 μm or more.
A decorative sheet characterized by that.
2. Item 2. The decorative sheet according to Item 1, wherein the transparent resin layer further has a third transparent resin layer under the second transparent resin layer.
3. 3. Item 2. The decorative sheet according to Item 1 or 2, which has an embossed shape on the surface protective layer side.
4. Item 2. The decorative sheet according to any one of Items 1 to 3, wherein the surface protective layer contains an ionizing radiation curable resin or a two-component curable urethane resin.
5. Item 2. The decorative sheet according to any one of Items 1 to 4, wherein the surface protective layer contains an antiviral agent.
6. Item 2. The decorative sheet according to any one of Items 1 to 5, further comprising a transparent adhesive layer, a pattern layer, and a base material sheet under the transparent resin layer.
7. A decorative material having the decorative sheet according to any one of Items 1 to 6 on an adherend.

The decorative sheet of the present invention is excellent in scratch resistance and impact resistance, cracks during bending are suppressed, and is excellent in impact resistance under cold temperature, and cracks during bending even under cold temperature are excellent. Is suppressed.

It is a schematic diagram which shows the example of the layer structure of the decorative sheet and the decorative material of this invention. FIG. 1 (a) shows an example of the layer structure of the decorative sheet of the present invention having a synthetic resin backer layer, and FIG. 1 (b) shows an example of the layer structure of the decorative sheet of the present invention having no synthetic resin backer layer. 1 (c) shows an example of the layer structure of the decorative material of the present invention. It is a figure explaining the method of measuring the indentation hardness in this specification.

Hereinafter, the decorative sheet and the decorative material of the present invention will be described in detail. In the decorative sheet of the present invention, the surface is a so-called "front surface", which is a surface that comes into contact with the adherend when the decorative sheet of the present invention is laminated on the adherend or the like. Is the opposite surface, which is visible after stacking. Further, in the present specification, with respect to the decorative sheet of the present invention, the direction of the surface thereof may be referred to as "front" or "top", and the opposite side thereof may be referred to as "back" or "bottom". Further, in the following description, the lower and upper limits of the numerical range represented by "-" mean "greater than or equal to or less than" (for example, if α to β, it is greater than or equal to α or less than β).

1. 1. Decorative sheet The decorative sheet of the present invention is a decorative sheet having at least a transparent resin layer under the surface protective layer, and (1) the transparent resin layer is a first transparent resin in order from the surface protective layer side. It has a layer and a second transparent resin layer, (2) the first transparent resin layer has a thickness of 10 μm or more and less than 20 μm, and an indentation hardness of 80 MPa or more, and (3) the first transparent resin layer. The 2 transparent resin layer has a thickness of 35 μm or more and an indentation hardness of 40 MPa or more and 70 MPa or less. (4) The first transparent resin layer and the second transparent resin layer are polypropylene-based. It contains a resin, and (5) the total thickness of the first transparent resin layer and the thickness of the second transparent resin layer is 60 μm or more.

The decorative sheet of the present invention having the above characteristics has a surface protective layer and is therefore excellent in scratch resistance. Further, the transparent resin layer has a first transparent resin layer on the surface protective layer side, and the indentation hardness of the first transparent resin layer is 80 MPa or more, so that it is hard and has a thickness of 10 μm or more and 20 μm. Since it is less than or equal to and has an appropriate thickness, deformation and impact due to rubbing on the surface of the decorative sheet can be appropriately released downward, and it is excellent in scratch resistance and impact resistance. Further, the transparent resin layer has a second transparent resin layer on the side opposite to the surface protective layer of the first transparent resin layer, and the indent hardness of the second transparent resin layer is 40 MPa or more. Since it is 70 MPa or less, it is softer than the first transparent resin layer, and has an appropriate thickness of 35 μm or more. Therefore, the thickness of the first transparent resin layer is 10 μm or more and less than 20 μm. Rubbing and impact on the sheet surface can be dispersed and absorbed by the entire surface protective layer, first transparent resin layer and second transparent resin layer, and has excellent scratch resistance and impact resistance during bending. Cracking can be suppressed.

Further, in the decorative sheet of the present invention, the first transparent resin layer and the second transparent resin layer contain a polypropylene-based resin, each of which exhibits a specific thickness and indentation hardness, and the first transparent resin. When the total thickness of the layer and the thickness of the second transparent resin layer is 60 μm or more, cracking during bending is suppressed.

Further, in the decorative sheet of the present invention, (2) the first transparent resin layer has a thickness of 10 μm or more and less than 20 μm, and an indentation hardness of 80 MPa or more, and (3) the second transparency. The resin layer has excellent impact resistance under cold temperature and is bent even at cold temperature by satisfying the requirement that the thickness is 35 μm or more and the indentation hardness is 40 MPa or more and 70 MPa or less. Time cracking is suppressed.

That is, the decorative sheet of the present invention is excellent in scratch resistance and impact resistance by having all of the above-mentioned configurations, and cracking during bending is suppressed. It is excellent and can have all the characteristics that cracking during bending is suppressed even under cold temperature.

In the present specification, the "cold temperature" is a temperature in a general cold region, and examples thereof include 20 ° C. or lower, a lower temperature of 15 ° C. or lower, and a lower temperature of 5 ° C. or lower. Further, the lower limit of the temperature in the cold region is not particularly limited, and is about 10 ° C. or higher below the freezing point.

In the present specification, the "indentation hardness" of each layer is measured by using the micro-region mechanical property evaluation device Tribo Indenter (registered trademark) "TI-950" (manufactured by Bruker). Shown by.

_{The method for measuring the indentation hardness (HIT} ) of each layer using the tribo indenter (registered trademark) "TI-950" is as follows.

(1) As the indenter of the nano indenter, a Berkovich indenter (model number: TI0039) having a triangular pyramid shape shown in FIG. 2 (a) is used. As shown in FIG. 2 (b), the Berkovich indenter is pushed into the measurement sample under the pushing conditions described later, and the pushing depth h (nm) with respect to the pushing load F (μN) is continuously measured, and FIG. 2 (c) shows. Create a load-displacement curve as shown. _{The maximum pushing load F max} (μN) is obtained from the created load-displacement curve. Next, the hardness is obtained by dividing the maximum pushing load F _max (μN) by the contact projected area Ap (μm ^{2) between the indenter and the sample at that time.} Here, Ap is a contact projection area in which the indenter tip curvature is corrected by the apparatus standard method using the fused silica of the standard sample.
That is, H _IT = F _max / Ap.
(2) The pushing conditions are as shown in FIG. 2 (c) at room temperature (23 ± 5 ° C.), where a load of 0 to 50 μN is first applied in 5 seconds (that is, 10 μN / s), and then 50 μN (F). _{Hold for 5 seconds with a load of max} ), and finally unload from 50 to 0 μN in 5 seconds.
(3) When measuring the hardness, the hardness of the cross section of the layer to be measured is measured in order to avoid the influence of the hardness of the layer other than the layer as the measurement sample. That is, the decorative sheet is embedded with a resin (normal temperature curing type epoxy two-component curing resin), left at room temperature for 24 hours or more to be cured, and then the cured embedded sample is prepared with a sharp knife (for example, an electron microscope section preparation). The sample is carved out so that the Berkovich indenter can be pushed in, and the cross section of the layer to be measured is exposed. The hardness of the cross section is measured by pushing the Berkovich indenter into the position where the fine particles are avoided). (4) The indentation hardness of 10 or more points is measured for the layer to be measured, and the average value of the 10 points measured with good reproducibility is used as the measured value.

In the present invention, the following can be confirmed. That is, the indentation hardness can be appropriately set by mixing two or more kinds of resins having different hardness, mixing an elastomer with the resin, and the like. Further, the indentation hardness can be appropriately adjusted by adjusting the cooling temperature such as the chill roll temperature when the resin is melt-kneaded at a high temperature and then cooled. When the cooling temperature is increased, the cooling rate is lowered, so that the crystallinity of the resin is increased and the indentation hardness is increased. Further, when the cooling temperature is lowered, the cooling rate is increased, so that the crystallinity of the resin is lowered and the indentation hardness is lowered.

The decorative sheet of the present invention has at least a transparent resin layer under the surface protective layer, and the transparent resin layer is a first transparent resin layer and a second transparent resin layer in order from the surface protective layer side. As long as it has, the specific layer structure is not limited. For example, a decorative sheet having an adhesive layer, a pattern layer, and a base material sheet on the surface of the transparent resin layer opposite to the surface protective layer can be mentioned. Further, the decorative sheet of the present invention may have a synthetic resin backer layer on the surface of the base material sheet opposite to the transparent resin layer and the surface protective layer. Hereinafter, each layer will be specifically described with a decorative sheet having such a layer structure as a typical example.

Surface protective layer The decorative sheet of the present invention has a surface protective layer. The resin forming the surface protective layer preferably contains at least one type of curable resin such as a thermoplastic resin, a thermosetting resin, or an ionization radiation curable resin. In particular, the ionizing radiation curable resin is preferable from the viewpoint of high surface hardness, productivity and the like. Further, the electron beam curable resin is most preferable from the viewpoint of further improving the weather resistance.

Examples of the thermoplastic resin include vinyl chloride resin, polypropylene resin, polyethylene resin, polyester resin, acrylic resin, ionomer resin and the like.

Examples of the heat-curable resin include unsaturated polyester resin, polyurethane resin (including two-component curable polyurethane), epoxy resin, aminoalkyd resin, phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, and melamine. -Urea cocondensation resin, silicon resin, polysiloxane resin and the like can be mentioned.

The surface protective layer preferably contains an ionizing radiation curable resin or a two-component curable urethane resin. When the surface protective layer contains these resins, it is easy to further improve the abrasion resistance, impact resistance, stain resistance, scratch resistance, weather resistance, etc. of the decorative sheet.

A cross-linking agent, a polymerization initiator, a curing agent, a polymerization accelerator and the like can be added to the resin. For example, as a curing agent, isocyanate, organic sulfonate, etc. can be added to unsaturated polyester resin, polyurethane resin, etc., organic amine, etc. can be added to epoxy resin, peroxide such as methyl ethyl ketone peroxide, azoisobutylnitrile, etc. A radical initiator can be added to the unsaturated polyester resin.

Examples of the method for forming the surface protective layer with the thermosetting resin include a method in which a solution of the thermosetting resin is applied by a coating method such as a roll coating method or a gravure coating method, and dried and cured. The amount of the solution applied is approximately 5 to 50 μm, preferably about 5 to 40 μm in terms of solid content.

The ionizing radiation curable resin is not limited as long as it is a resin that undergoes a cross-linking polymerization reaction by irradiation with ionizing radiation and changes into a three-dimensional polymer structure. For example, one or more of prepolymers, oligomers and monomers having a polymerizable unsaturated bond or an epoxy group in the molecule that can be crosslinked by irradiation with ionizing radiation can be used. For example, acrylate resins such as urethane acrylates, polyester acrylates and epoxy acrylates; silicon resins such as siloxane; polyester resins; epoxy resins and the like can be mentioned.

Examples of the ionizing radiation include ultraviolet rays (near ultraviolet rays, vacuum ultraviolet rays, etc.), X-rays, electron beams, ionizing rays, etc. Among them, ultraviolet rays and electron beams are preferable, and electron beams are more preferable.

As the ultraviolet source, a light source of an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light fluorescent lamp, or a metal halide lamp can be used. The wavelength of ultraviolet rays is about 190 to 380 nm.

As the electron beam source, for example, various electron beam accelerators such as Cockcroft-Walt type, Van de Graaff type, resonance transformer type, insulated core transformer type, linear type, dynamitron type, and high frequency type can be used. The energy of the electron beam is preferably about 100 to 1000 keV, more preferably about 100 to 300 keV. The irradiation amount of the electron beam is preferably about 2 to 15 Mrad.

The ionizing radiation curable resin is sufficiently cured by irradiating it with an electron beam, but when it is cured by irradiating it with ultraviolet rays, it is preferable to add a photopolymerization initiator (sensitizer).

In the case of a resin system having a radically polymerizable unsaturated group, the photopolymerization initiator is, for example, acetophenone, benzophenone, thioxanthone, benzoin, benzoin methyl ether, Michler benzoyl benzoate, Michler ketone, diphenyl sulfide, dibenzyl disulfide. , Diethyl oxide, triphenylbiimidazole, isopropyl-N, N-dimethylaminobenzoate and the like can be used. In the case of a resin system having a cationically polymerizable functional group, at least one of, for example, an aromatic diazonium salt, an aromatic sulfonium salt, a metallocene compound, a benzoin sulfonic acid ester, and a freeleoxysulfoxonium diallyl iodosyl salt. Can be used.

The amount of the photopolymerization initiator added is not particularly limited, but is generally about 0.1 to 10 parts by mass with respect to 100 parts by mass of the ionizing radiation curable resin.

As a method of forming the protective layer with the ionizing radiation curable resin, for example, a solution of the ionizing radiation curable resin may be applied by a coating method such as a gravure coating method or a roll coating method.

The thickness of the surface protective layer is not particularly limited as long as it exhibits the required performance, but is preferably 3 to 45 μm, more preferably 5 to 35 μm, and even more preferably 10 to 25 μm. When the lower limit of the thickness of the surface protective layer is within the above range, the scratch resistance of the decorative material of the present invention is further improved. Further, when the upper limit of the thickness of the surface protective layer is within the above range, the post-processability (wrapping process, V-cut process) of the decorative material of the present invention is further improved.

In order to further impart scratch resistance and abrasion resistance to the surface protective layer formed of the ionizing radiation curable resin, an inorganic filler may be added. Examples of the inorganic filler include powdered aluminum oxide, silicon carbide, silicon dioxide, calcium titanate, barium titanate, magnesium pyrobolate, zinc oxide, silicon nitride, zirconium oxide, chromium oxide, iron oxide, and boron nitride. Examples include diamond, Kongo sand, and glass fiber.

The amount of the inorganic filler added is about 1 to 80 parts by mass with respect to 100 parts by mass of the ionizing radiation curable resin.

The surface protective layer may contain additives other than the above-mentioned inorganic filler, if necessary. Examples of additives include fillers such as calcium carbonate and clay, flame retardants such as magnesium hydroxide, antioxidants, lubricants, foaming agents, ultraviolet absorbers, light stabilizers, deodorants, antibacterial agents, and antiviruses. Examples include agents, anti-allergen agents, antifungal agents and the like.

The surface protective layer preferably contains an antiviral agent. Antiviral agents can be broadly classified into organic and inorganic agents. Examples of the organic antiviral agent include quaternary ammonium salt-based, quaternary phosphonium salt-based, pyridine-based, pyrithione-based, benzimidazole-based, organic iodine-based, isothiazoline-based, and anionic antiviral agents. .. Examples of the inorganic antiviral agent include antiviral agents in which metal ions such as silver, copper, and zinc are supported on zeolite, apatite, zirconia, glass, and the like.

Among the above organic antiviral agents, benzimidazole antiviral agents or anionic antiviral agents, which are antiviral agents that maintain the particle shape, are particularly preferably used. When the antiviral agent retains its particle shape, it means that the antiviral agent does not dissolve in the composition (ink before curing) for forming the surface protective layer, but in the state of particles in the surface protective layer after curing. It means that it exists. Therefore, in the process of forming the surface protective layer, the particles of the antiviral agent are likely to emerge, and the particles of the antiviral agent can be easily unevenly distributed on the outermost surface side of the surface protective layer. By unevenly distributing the particles of the antiviral agent on the outermost surface side of the surface protective layer, it is possible to suppress the amount of the antiviral agent added in order to obtain a predetermined antiviral property. It is possible to easily suppress a decrease in scratch resistance.

As the anionic antiviral agent, for example, those containing a styrene polymer derivative compound and an unsaturated carboxylic acid derivative compound are preferable. Further, the styrene polymer derivative compound and the unsaturated carboxylic acid derivative compound preferably contain at least one of the structures of styrene, sodium sulfonate, acrylic acid, maleic acid, and fumaric acid, and may include all the structures. More preferred. This is because there are two types of viruses with and without envelope, and it is considered that the structures of antiviral agents that can effectively inhibit the activity of each type are different.

As the above-mentioned inorganic antiviral agent, a silver-based antiviral agent is preferable from the viewpoint of non-biotoxicity and excellent safety, and among them, a phosphoric acid-based glass-silver-supporting compound or a silver zeolite compound exhibits antiviral performance even in a small amount. Therefore, the amount of addition can be suppressed, which is more preferable.

The antiviral agent may be used alone or in combination of two or more.

Transparent resin layer The decorative sheet of the present invention has a transparent resin layer under the surface protective layer. The transparent resin layer is not particularly limited as long as it is transparent, and may be colorless transparent, colored transparent, translucent, or the like. Further, the transparent resin layer has a first transparent resin layer and a second transparent resin layer in this order from the surface protection layer side.

(First transparent resin layer)
The thickness of the first transparent resin layer is 10 μm or more and less than 20 μm. If the thickness is less than 10 μm, the scratch resistance of the decorative sheet is lowered. Further, if the thickness exceeds 20 μm, the impact resistance of the decorative sheet and the impact resistance under cold temperature are lowered, and cracking during bending processing at cold temperature cannot be suppressed. The thickness of the first transparent resin layer is preferably 12 μm or more, and more preferably 14 μm or more in that the scratch resistance is further improved. The thickness of the first transparent resin layer is preferably 18 μm or less in that the impact resistance under cold temperature and the bending workability at cold temperature are further improved.

The first transparent resin layer has an indentation hardness of 80 MPa or more. If the indentation hardness of the first transparent resin layer is less than 80 MPa, the scratch resistance of the decorative sheet is lowered. The indentation hardness of the first transparent resin layer is preferably 100 MPa or more in that the scratch resistance of the decorative sheet of the present invention is further improved. Further, the upper limit of the indentation hardness of the first transparent resin layer is not particularly limited, and is preferably 160 MPa or less. When the upper limit of the indentation hardness of the first transparent resin layer is within the above range, the decorative sheet of the present invention is further excellent in scratch resistance, and cracking during bending is further suppressed.

The first transparent resin layer contains a polypropylene-based resin described later. The content of the polypropylene-based resin in the first transparent resin layer may be 100% by mass or less, or 95% by mass or less. The content of the polypropylene-based resin in the first transparent resin layer is preferably 80% by mass or more, more preferably 90% by mass or more.

The first transparent resin layer may contain a thermoplastic elastomer described later in order to adjust the indentation hardness. The content of the thermoplastic elastomer in the first transparent resin layer is preferably 20% by mass or less, more preferably 10% by mass or less. Further, the lower limit of the content of the thermoplastic elastomer in the first transparent resin layer is not particularly limited, and may be 0% by mass or 10% by mass or more.

The first transparent resin layer may contain a crystal nucleating agent in order to adjust the indentation hardness. Examples of the crystal nucleating agent include a phosphate ester metal salt and a sorbitol-based crystal nucleating agent. Among these, a phosphate ester metal salt is preferable from the viewpoint of improving the indentation hardness.

The content of the crystal nucleating agent in the first transparent resin layer is preferably 0.1% by mass or more, more preferably 0.2% by mass or more.

(Second transparent resin layer)
The thickness of the second transparent resin layer is 35 μm or more. If the thickness is less than 35 μm, the scratch resistance and impact resistance of the decorative sheet are lowered. The thickness of the second transparent resin layer is preferably 40 μm or more. The upper limit of the thickness of the second transparent resin layer is not particularly limited, and is preferably 100 μm or less, more preferably 90 μm or less. When the upper limit of the thickness of the second transparent resin layer is within the above range, cracking of the decorative sheet of the present invention during bending is further suppressed.

The second transparent resin layer has an indentation hardness of 40 MPa or more and 70 MPa or less. If the indentation hardness of the second transparent resin layer is less than 40 MPa, the scratch resistance of the decorative sheet is lowered. Further, when the indentation hardness exceeds 70 MPa, the impact resistance of the decorative sheet of the present invention and the impact resistance under cold temperature are lowered, and cracking during bending processing at cold temperature is not suppressed. The indentation hardness of the second transparent resin layer is preferably 50 MPa or more from the viewpoint of further improving the scratch resistance. Further, the indentation hardness of the second transparent resin layer further improves the impact resistance of the decorative sheet of the present invention and the impact resistance under cold temperature, and further cracks during bending processing at cold temperature. 65 MPa or less is preferable, and 60 MPa or less is more preferable in terms of being suppressed.

The second transparent resin layer contains a polypropylene-based resin described later. The content of the polypropylene-based resin in the second transparent resin layer is preferably 90% by mass or less, more preferably 85% by mass or less. The content of the polypropylene-based resin in the second transparent resin layer is preferably 30% by mass or more, more preferably 40% by mass or more.

The second transparent resin layer may contain a thermoplastic elastomer described later in order to adjust the indentation hardness. The content of the thermoplastic elastomer in the second transparent resin layer is preferably 60% by mass or less, more preferably 70% by mass or less. The content of the thermoplastic elastomer in the second transparent resin layer is preferably 10% by mass or more, more preferably 15% by mass or more.

Since it is presumed that it is preferable to lower the glass dislocation temperature of polypropylene in order to improve the impact resistance under cold temperature and suppress cracking during bending, the second transparent resin layer is phased with the polypropylene resin. It preferably contains a highly soluble thermoplastic elastomer. Examples of such thermoplastic elastomers include hydrogenated styrene- (ethylene-butylene) -based elastomers and polypropylene-based elastomers.

(Third transparent resin layer)
The transparent resin layer may further have a third transparent resin layer under the second transparent resin layer. When the transparent resin layer has the third transparent resin layer, the scratch resistance and impact resistance of the decorative sheet of the present invention are further improved.

The thickness of the third transparent resin layer is preferably 5 μm or more, more preferably 10 μm or more. The thickness of the third transparent resin layer is preferably 90 μm or less, more preferably 40 μm or less.

The indentation hardness of the third transparent resin layer is preferably 60 MPa or less, preferably 50 MPa or less, and more preferably 40 MPa or less. By setting the indentation hardness of the third transparent resin layer within the above range, the scratch resistance and impact resistance of the decorative sheet of the present invention are further improved, and cracking during bending is further suppressed.

The thickness and indentation hardness of the third transparent resin layer are preferably equal to or less than the thickness and indentation hardness of the second transparent resin layer. With this configuration, the scratch resistance and impact resistance of the decorative sheet of the present invention can be further improved.

The third transparent resin layer preferably contains a polypropylene-based resin described later. The content of the polypropylene-based resin in the third transparent resin layer may be 100% by mass or less, or 90% by mass or less by adding a thermoplastic elastomer to adjust the indentation hardness. It may be. The content of the polypropylene-based resin in the third transparent resin layer is preferably 15% by mass or more, more preferably 20% by mass or more.

In the third transparent resin layer, an acid-modified propylene-based resin may be used as the polypropylene-based resin. By containing the acid-modified polypropylene-based resin in the third transparent resin layer, the adhesiveness with the pattern layer is further improved.

The third transparent resin layer may contain a thermoplastic elastomer in order to adjust the indentation hardness. The content of the thermoplastic elastomer in the third transparent resin layer is preferably 85% by mass or less, more preferably 80% by mass or less. Further, the lower limit of the content of the thermoplastic elastomer in the third transparent resin layer is not particularly limited, and may be 0% by mass or more, 10% by mass or more, or 15% by mass or more. It may be.

The total thickness of the first transparent resin layer and the thickness of the second transparent resin layer is 60 μm or more. When the total thickness is less than 60 μm, the scratch resistance and impact resistance of the decorative sheet of the present invention are lowered. The total thickness is preferably 70 μm or more, more preferably 80 μm or more. The total thickness is preferably 130 μm or less, more preferably 120 μm or less, and even more preferably 100 μm or less. When the upper limit of the thickness is within the above range, cracking of the decorative sheet of the present invention during bending is further suppressed.

The first transparent resin layer and the second transparent resin layer contain a polypropylene-based resin as described above. Further, it is preferable that the third transparent resin layer formed as needed also contains the polypropylene-based resin. As the polypropylene-based resin, either a homopolymer or a copolymer can be used. For example, homopolypropylene resin, random polypropylene resin, block polypropylene resin and the like can be mentioned. A polypropylene-based resin having stereoregularity is preferable. When a polypropylene-based resin is used, it is desirable to mold the molten polypropylene-based resin by an extrusion method to form a transparent resin layer. As the polypropylene-based resin, commercially available products (Prime Polymer Co., Ltd. Prime TPO "J-5900", Prime Polypro "F219DA", etc.) can be used.

The first transparent resin layer, the second transparent resin layer, and the third transparent resin layer formed as needed may contain a thermoplastic elastomer as described above. Since the transparent resin layer contains the thermoplastic elastomer, the indentation hardness of the transparent resin layer is lowered, so that the indentation hardness of the transparent resin layer can be appropriately adjusted to a desired hardness. Further, in order to improve the impact resistance under cold temperature and suppress cracking during bending, it is presumed that the glass dislocation temperature of polypropylene is lowered. Therefore, the transparent resin layer is compatible with the polypropylene resin. It preferably contains a highly soluble thermoplastic elastomer.

The thermoplastic elastomer as described above is not particularly limited, and for example, a styrene-based thermoplastic elastomer can be preferably used. Examples of the styrene-based thermoplastic elastomer include a random copolymer of one or more diene and styrene selected from the group consisting of isoprene, butadiene, and isobutylene, and hydrogenated products thereof; polyisoprene and hydrogenated poly. From isoprene, polybutadiene (1,2-polybutadiene, 1,4-polybutadiene), hydrogenated polybutadiene (hydrogenated 1,2-polybutadiene, 1,4-polybutadiene), polyisobutylene, polyethylene, polypropylene and polyvinyl Examples include a copolymer of one or more blocks selected from the above group and a polystyrene block, hydrogenated products thereof; and a mixture of these copolymers.

Specific examples of the styrene-based thermoplastic elastomer include hydrogenated styrene-butadiene random copolymer (h-SBR), polystyrene-polyisoprene-polystyrene block copolymer (SIS), and polystyrene-polybutadiene-polystyrene block copolymer. (SBS), hydrogenated styrene butadiene block copolymer [polystyrene-hydrogenated-1,2-polybutadiene-hydrogenated-1,4-polybutadiene-polystyrene block copolymer (SEBS)], hydrogenated styrene isoprene block copolymer Combined [Polymer-hydrogenated polyisoprene-polystyrene block copolymer (SEPS)], polystyrene-vinyl-polyisoprene-polystyrene block copolymer (SHIVS), polystyrene-hydrogenated polybutadiene-hydrogenated polyisoprene block copolymer, Examples thereof include polystyrene-polyisobutylene block copolymers, polystyrene-polyisobutylene-polystyrene block copolymers (SIBS), and polystyrene-hydrogenated polybutadiene-polyisoprene-polystyrene copolymers. Among these, it is preferable to use a hydrogenated styrene-butadiene block copolymer.

The styrene-based thermoplastic elastomer may be used alone or in combination of two or more. Further, it is preferable to use the above-mentioned hydrogenated additive in which the double bond of the conjugated diene is saturated by 80% or more.

Commercially available styrene-based elastomers include, for example, Septon 4077, Septon 4055, Septon 8105 (all trade names, manufactured by Kuraray), Dynaron 1320P, Dynaron 4600P, 6200P, 8601P, 9901P (all trade names, manufactured by JSR Corporation). ).

The transparent resin layer may contain a filler, a matting agent, a foaming agent, a flame retardant, a lubricant, an antistatic agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a radical scavenger, and a soft component (as needed). For example, various additives such as rubber) may be contained.

If necessary, the transparent resin layer may be subjected to a corona discharge treatment in order to improve the adhesion with the adjacent layer and the primer layer.

Base sheet The base sheet is preferably formed of, for example, a thermoplastic resin. Specifically, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyethylene, polypropylene, polycarbonate, polyethylene naphthalate, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester Examples thereof include polymers, ionomers, polyacrylic acid esters, and polymethacryl acid esters. Among the above, polyolefins such as polypropylene are preferable.

The base sheet may be colored. In this case, a coloring material (pigment or dye) can be added to the above-mentioned thermoplastic resin to color it. As the coloring material, for example, inorganic pigments such as titanium dioxide, carbon black and iron oxide, organic pigments such as phthalocyanine blue, and various dyes can be used. These can be selected from one or more of known or commercially available ones. In addition, the amount of the coloring material added may be appropriately set according to the desired color and the like.

The base sheet contains various additives such as fillers, matting agents, foaming agents, flame retardants, lubricants, antistatic agents, antioxidants, UV absorbers, light stabilizers, etc., as required. You may be.

Examples of the filler include silica, clay, calcium carbonate, aluminum hydroxide, magnesium hydroxide, antimony trioxide, zinc borate, molybdenum compound and the like. By including the filler, the effect of improving the surface characteristics and the like can be obtained. The content of the filler is preferably about 0 to 100 parts by weight, more preferably about 10 to 50 parts by weight, based on 100 parts by weight of the resin component.

The thickness of the base sheet can be appropriately set depending on the intended use, usage method, etc. of the final product, but is generally preferably 50 to 250 μm.

If necessary, the surface (front surface) of the base sheet may be subjected to a corona discharge treatment in order to enhance the adhesion of the ink forming the pattern layer. The method and conditions of the corona discharge treatment may be carried out according to a known method. Further, if necessary, the back surface of the base sheet may be subjected to a corona discharge treatment.

Backside Primer Layer A backside primer layer may be provided on the back surface of the above-mentioned base material sheet, if necessary. For example, it is advantageous when the base sheet and the adherend are adhered to produce a decorative material for a floor.

The back surface primer layer can be formed by applying a known primer agent to the back surface of the base sheet. Examples of the primer agent include a urethane resin-based primer made of an acrylic-modified urethane resin (acrylic urethane-based resin) and the like, and a urethane-cellulose-based resin (for example, a resin obtained by adding hexamethylene diisocyanate to a mixture of urethane and nitrified cotton. ), A resin-based primer made of a block copolymer of acrylic and urethane, and the like. Additives may be added to the primer, if necessary. Examples of the additive include a filler such as calcium carbonate and clay, a flame retardant such as magnesium hydroxide, an antioxidant, a lubricant, a foaming agent, an ultraviolet absorber, and a light stabilizer. The blending amount of the additive can be appropriately set according to the product characteristics.

The thickness of the back surface primer layer is not particularly limited, but is usually 0.1 to 10 μm, preferably about 1 to 5 μm.

Primer layer for forming a pattern layer Further, a primer layer for forming a pattern layer may be provided on the surface (front surface) of the above-mentioned base material sheet, if necessary. For example, it is advantageous when the base material sheet and the pattern layer are adhered to produce a decorative material.

The pattern layer forming primer layer can be formed by applying a known primer agent to the surface (front surface) of the base material sheet. As the primer agent, the same one used for the above-mentioned back surface primer layer can be used.

The thickness of the primer layer for forming the pattern layer is not particularly limited, but is usually 0.1 to 10 μm, preferably about 1 to 5 μm.

Pattern pattern layer The decorative sheet of the present invention may be provided with a pattern pattern layer on the surface (front surface) of the base material sheet, if desired.

The pattern pattern layer imparts a desired pattern (design) to the decorative sheet, and the type of pattern and the like are not limited. For example, wood grain pattern, stone grain pattern, sand grain pattern, tiled pattern, brickwork pattern, cloth grain pattern, leather squeezing pattern, geometric figure, character, symbol, abstract pattern and the like can be mentioned.

The method for forming the pattern layer is not particularly limited, and for example, an ink obtained by dissolving (or dispersing) a known colorant (dye or pigment) in a solvent (or dispersion medium) together with a binder resin is used. It may be formed on the surface of the base sheet by a printing method.

Examples of colorants include inorganic pigments such as carbon black, titanium white, zinc flower, petal pattern, dark blue, and cadmium red; azo pigments, lake pigments, anthraquinone pigments, quinacridone pigments, phthalocyanine pigments, isoindolinone pigments, and dioxazine pigments. Organic pigments such as; metal powder pigments such as aluminum powder and bronze powder; pearl luster pigments such as titanium oxide-coated mica and bismuth oxide; fluorescent pigments; luminous pigments and the like. These colorants can be used alone or in combination of two or more. Fillers such as silica, extender pigments such as organic beads, neutralizers, surfactants and the like may be further added to these colorants.

As the binder resin, in addition to polyester-based urethane resin and hydrophilic-treated polyester-based urethane resin, polyester, polyacrylate, polyvinyl acetate, polybutadiene, polyvinyl chloride, chlorinated polypropylene, polyethylene, polystyrene, and polystyrene-acrylate are all used. Polymers, rosin derivatives, alcohol adducts of styrene-maleic anhydride copolymers, cellulose-based resins and the like can also be used in combination.

More specifically, for example, polyurethane-polyacrylic resin, polyacrylamide resin, poly (meth) acrylic acid resin, polyethylene oxide resin, poly N-vinylpyrrolidone resin, water-soluble polyester resin, water-soluble. Polyamide-based resins, water-soluble amino-based resins, water-soluble phenol-based resins, and other water-soluble synthetic resins; water-soluble natural polymers such as polynucleotides, polypeptides, and polysaccharides; and the like can be used. Further, for example, natural rubber, synthetic rubber, polyvinyl acetate resin, (meth) acrylic resin, polyvinyl chloride resin, polyurethane-polyacrylic resin modified or mixed resin, and other resins can also be used. The binder resin can be used alone or in combination of two or more.

Examples of the printing method used for forming the pattern layer include a gravure printing method, an offset printing method, a screen printing method, a flexographic printing method, an electrostatic printing method, and an inkjet printing method. Further, when forming a solid pattern layer (also referred to as a colored concealing layer) on the entire surface, for example, a gravure coating method, a gravure reverse coating method, a roll coating method, a knife coating method, an air knife coating method, and a die coating method are used. Various coating methods such as a method, a lip coating method, a comma coating method, a kiss coating method, a flow coating method, and a dip coating method can also be mentioned.

In addition to the above, for example, a hand-painting method, a suminagashi method, a photographic method, a transfer method, a laser beam drawing method, an electron beam drawing method, a partial vapor deposition method for metals, an etching method, etc. are used, or in combination with other forming methods. You may use it.

The thickness of the pattern layer is not particularly limited and can be appropriately set according to the product characteristics, but the layer thickness at the time of coating is about 1 to 15 μm, and the layer thickness after drying is about 0.1 to 10 μm.

Colored concealment layer A colored concealment layer may be formed on the base material sheet, if necessary. The decorative sheet of the present invention preferably has a colored concealing layer between the base sheet and the pattern layer. The colored concealing layer is formed on the base sheet as a solid printing layer on the entire surface.

The colored concealing layer may be uniformly colored or may be a pattern layer to which various colors are imparted. By providing the colored concealing layer, the surface of the adherend can be concealed, and when the base sheet is colored or has uneven color, the intended color can be given to adjust the surface color. can.

The colored concealing layer can be, for example, a layer containing a pigment and a binder resin. This colored concealing layer can be formed by a known printing method such as gravure printing, flexographic printing, silk screen printing, offset printing, etc. using, for example, a printing ink containing a coloring material, a binder resin, and a solvent. These inks may be known or commercially available.

As the colorant, the binder resin and the solvent, those used for the above-mentioned pattern layer can be used.

The thickness of the colored concealing layer is usually about 0.5 to 20 μm, preferably 1 to 10 μm, and more preferably 1 to 5 μm. When the thickness of the colored concealing layer is within the above range, excellent designability can be imparted to the decorative sheet, and concealing property can be imparted.

Adhesive layer The decorative sheet of the present invention may be provided with an adhesive layer between the pattern layer and the transparent resin layer, if desired.

The adhesive layer may be transparent or translucent as long as the pattern layer can be recognized, but a transparent adhesive layer is preferable. The adhesive used in the adhesive layer is not particularly limited, and can be appropriately selected depending on the components constituting the pattern layer or the transparent resin layer. Examples of the adhesive known in the field of decorative sheets include thermoplastic resins such as polyamide resins, acrylic resins and vinyl acetate resins, and thermosetting resins such as urethane resins. These adhesives may be used alone or in combination of two or more. Further, a two-component curable polyurethane resin or polyester resin using isocyanate as a curing agent can also be applied.

Further, if necessary, known easy-adhesion treatments such as corona discharge treatment, plasma treatment, degreasing treatment, and surface roughening treatment can be applied to the adhesive surface.

The adhesive layer can be formed, for example, by applying an adhesive on the pattern layer, drying it once, and then laminating a transparent resin. The method of applying the adhesive is not particularly limited, and for example, roll coat, curtain flow coat, wire bar coat, reverse coat, gravure coat, gravure reverse coat, air knife coat, kiss coat, blade coat, smooth coat, comma coat, etc. The method can be adopted.

The thickness of the adhesive layer varies depending on the transparent protective layer, the type of adhesive used, and the like, but is generally about 0.1 to 30 μm.

Primer layer In the decorative sheet of the present invention, a primer layer may be provided between the transparent resin layer and the surface protective layer, if desired. The primer layer has a function of enhancing the adhesiveness (adhesion) between the transparent resin layer and the surface protective layer. Further, for example, it has an effect of making it difficult for fine cracks and whitening to occur in the stretched portion of the surface protective layer during bending. Further, by providing the primer layer, the formation of the surface protective layer becomes easy. The primer layer is not particularly limited as long as it is transparent, and includes any of colorless transparent, colored transparent, translucent and the like.

The primer layer can be formed by applying a known or commercially available primer agent on the transparent resin layer. In particular, the primer layer is preferably a layer formed by cross-linking a resin. Examples of the primer agent for forming such a layer include a urethane resin-based primer agent made of an acrylic-modified urethane resin and the like, a resin-based primer agent made of a block copolymer of acrylic and urethane, and the like. These primer agents may be used alone or in combination of two or more.

The primer layer may contain silica as a matting agent. The content of silica in the primer is preferably 0.1 to 50 parts by weight, more preferably 10 to 40 parts by weight, based on 100 parts by weight of the resin component. Further, if necessary, the primer agent may contain a known additive. For example, by incorporating a hexamethylene diisocyanate-based curing agent in the primer agent, the adhesion between the transparent resin layer and the surface protective layer can be further improved. Further, various weather resistant agents such as an ultraviolet absorber and a light stabilizer may be added to the primer layer.

The primer layer can be formed by, for example, a direct coating method, such as gravure coat, gravure reverse coat, gravure offset coat, spin coat, roll coat, reverse roll coat, kiss coat, wheeler coat, dip coat, solid coat by silk screen, wire. Bar coat, flow coat, comma coat, free-flow coat, brush coat, spray coat and the like can be used.

The thickness of the primer layer is preferably about 0.1 to 10 μm. When it is 0.1 μm or more, the effect of preventing cracking, breaking, whitening, etc. of the surface protective layer can be sufficiently exhibited. On the other hand, when the thickness of the primer layer is 10 μm or less, when the primer layer is applied, the coating film is stable in drying and curing, so that the moldability does not fluctuate, which is preferable. From the above points, the thickness of the primer layer is more preferably 0.1 to 10 μm.

Method for manufacturing decorative sheet For laminating each layer constituting the decorative sheet of the present invention, for example, (a) a backside primer layer is provided on the back surface of the base material sheet, and (b) a pattern pattern layer is provided on the front surface of the base material sheet. Is formed by printing, (c) an adhesive layer is formed on the pattern printing pattern layer, and (d) a second transparent resin layer and a first transparent layer formed on the adhesive layer by an extrusion lamination method. A transparent resin layer having a sex resin layer is laminated, and (e) the surface of the first transparent resin layer is subjected to corona discharge treatment, then a primer layer is formed, and (f) the surface is subjected to a gravure coating method. This can be done by applying an ionizing radiation curable resin that forms a surface protective layer and irradiating it with an electron beam.

The embossed decorative sheet may be embossed on the transparent resin layer and / or on the surface protective layer. The decorative sheet of the present invention preferably has an embossed shape on the surface protective layer side by the embossing process.

The embossing process is performed to give the decorative sheet a desired texture such as a wood grain pattern. For example, after the surface protective layer is heat-softened, it is pressed and shaped with an embossed plate having a desired uneven pattern, and then cooled and fixed to give a texture. The embossing can be performed with a known single-wafer or rotary embossing machine. Examples of the embossed uneven pattern include a wood grain conduit groove, a floating pattern (an uneven pattern of an embossed annual ring), a hairline, a sand grain, and a satin finish.

When embossed, if necessary, the embossed recess may be filled with ink by wiping. For example, the embossed recess is filled with ink while scratching the surface with a doctor blade. As the ink to be filled (wiping ink), an ink using a two-component curable urethane resin as a binder can be usually used. In particular, by performing wiping processing on the unevenness of the wood grain conduit groove, it is possible to enhance the commercial value by expressing a design closer to the actual wood grain.

The backer layer decorative sheet may be provided with a backer layer on the back surface of the base sheet. The back surface primer layer described above may be further provided on the front surface (the surface of the backer layer opposite to the side on which the surface protection layer and the transparent resin layer are laminated), which is the back surface side of the backer layer. ..

The resin constituting the backer layer is preferably a thermoplastic resin, for example, polyethylene, polypropylene, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polymethylene, polymethylpentene, polyethylene terephthalate, amorphous polyethylene terephthalate. (A-PET), polyalkylene terephthalate having high heat resistance [For example, polyethylene terephthalate in which a part of ethylene glycol is replaced with 1,4-cyclohexanedimethanol, diethylene glycol, etc., so-called trade name PET-G (Eastman Chemical). (Manufactured by Company)], polybutylene terephthalate, polycarbonate, polyarylate, polyethylene naphthalate, polyethylene naphthalate-isophthalate copolymer, polyimide, polystyrene, polyamide, ABS (acrylonitrile-butadiene-styrene copolymer) and the like. These resins can be used alone or in combination of two or more.

The thickness of the backer layer can be appropriately set depending on the intended use, usage method, etc. of the final product, but is generally preferably 50 to 800 μm.

If necessary, the backer layer may be subjected to a known easy-adhesion treatment such as a corona discharge treatment, a plasma treatment, a degreasing treatment, and a surface roughening treatment.

As a method for forming the backer layer, for example, the material used for the adhesive layer may be laminated by a calendar method, an inflation method, a T-die extrusion method, or the like, or a ready-made film may be used.

However, although the decorative sheet of the present invention can secure sufficient impact resistance, it is possible to further secure impact resistance by forming a backer layer.

The decorative sheet of the present invention described above can be suitably used as a decorative sheet for floors.

Decorative material A decorative material can be obtained by adhering and joining an adherend to the base sheet side of the decorative sheet of the present invention.

The material of the various adherends is not particularly limited, and examples thereof include inorganic non-metal-based, metal-based, wood-based, and plastic-based materials. Specifically, in the case of inorganic non-metallic cement, for example, abstract cement, extruded cement, slag cement, ALC (lightweight cellular concrete), GRC (glass fiber reinforced concrete), pulp cement, wood piece cement, asbestos cement, calcium silicate, etc. Examples include non-ceramic ceramic materials such as gypsum and gypsum slag, and ceramic materials such as earthenware, pottery, porcelain, cement, glass, and amber. Examples of the metal system include metal materials (metal steel plates) such as iron, aluminum, and copper. Examples of wood-based materials include veneer made of cedar, cypress, oak, lauan, teak and the like, plywood, particle board, fiber board, laminated lumber and the like. Examples of plastics include resin materials such as polypropylene, ABS resin, and phenol resin.

The shape of such an adherend is not particularly limited, and usually, a flat plate may be used in consideration of installation on flooring or the like.

An adhesive can be used, for example, to bond the adherend and the decorative sheet. Examples of the adhesive include urethane, acrylic, urethane / acrylic, polyvinyl acetate, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ionomer, butadiene / acrylic nitrile rubber, and neoprene rubber. , Known adhesives containing natural rubber or the like as an active ingredient can be used.

After joining the adherend and the decorative sheet, for example, cutting, sane processing using a tenoner, V-shaped groove giving, chamfering on all sides, etc. may be performed according to the characteristics of the final product.

The decorative material of the present invention described above can be suitably used as a decorative material for floors.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. However, the present invention is not limited to the embodiments of the examples.

Example 1
(Preparation of transparent resin layer)
Using a two-kind two-layer extruder, the resins having the formulations shown in Table 1 as the first transparent resin layer and the second transparent resin layer were extruded under the condition of a resin temperature of 235 ° C. at the time of processing, and 40 ° C. A transparent resin layer in which a first transparent resin layer and a second transparent resin layer were laminated was prepared by cooling by passing the chill roll of the above. The thickness of the first transparent resin layer was 18 μm, and the indentation hardness was 90 MPa. The thickness of the second transparent resin layer was 45 μm, and the indentation hardness was 55 MPa.

(Preparation of decorative sheet)
Both sides of a base sheet made of a colored polypropylene film having a thickness of 60 μm were subjected to corona discharge treatment, and a backside primer layer having a thickness of 2 μm was formed on the back surface. Next, a pattern layer having a thickness of 2 μm is formed on the front surface of the base material sheet by printing, and further, a transparent adhesive layer is used on the pattern print pattern layer using a urethane-based dry laminating adhesive. Was formed. Next, the transparent resin layer prepared as described above was laminated on the transparent adhesive layer so that the second transparent resin layer side was in contact with the transparent adhesive layer.

The transparent resin layer is subjected to corona discharge treatment, and the treated surface is coated with an acrylic urethane resin (100 parts by weight of acrylic polyol plus 5 parts by weight of hexamethylene diisocyanate) by a gravure coating method to protect the surface. A primer layer for use was formed. The thickness of the primer layer for the surface protective layer was 1 μm.

A urethane acrylate-based electron beam-curable resin is applied on the primer layer for the surface protective layer by a roll coating method, dried, and then the uncured electron beam-curable resin layer is coated with an electron beam (electron beam (electron beam) in an environment with an oxygen concentration of 200 ppm or less. It was cured by irradiating it with an acceleration voltage of 175 KeV and an irradiation amount of 5 Mrad) to form a surface protective layer made of an electron beam curable resin. The thickness of the surface protective layer was 15 μm.

Next, a decorative sheet was produced by embossing from the surface protective layer side with a wood grain conduit-like embossing plate having a plate depth of 50 μm to form a wood grain conduit-like uneven pattern.

In the examples and comparative examples, the resins used for forming the surface protective layer and the transparent resin layer are as follows.
-Electronic beam curable resin (EB): Urethane acrylate-based electron beam-curable resin-UV curable resin (UV): Urethane acrylate-based UV curable resin-Homo polypropylene resin (homo PP): Polypropylene homopolymer (mesopentad fraction) 98%)
Thermoplastic elastomer (SEBS): Hydrogenated styrene-butadiene block copolymer (polystyrene-hydrogenated-1,2-polybutadiene-hydrogenated-1,4-polybutadiene-polystyrene block copolymer)
-Ionomer: Zinc ion cross-linked polymer of ethylene-methacrylic acid copolymer

(Making decorative materials)
Urethane-modified ethylene-vinyl acetate emulsion adhesive is uniformly applied on a medium density wood fiberboard (MDF) with a thickness of 3 mm at 100 g / m ² wet, and a decorative sheet is attached and cured at room temperature for 3 days. A decorative material was produced by the above.

Examples 2-5, Comparative Examples 1-6
Example 1 except that the resin forming the surface protective layer, the thickness, and the resin forming the first transparent resin layer and the second transparent resin layer, the thickness, and the indentation hardness were changed as shown in Table 1. In the same manner as in the above, decorative sheets and cosmetic materials of Examples 2 to 5 and Comparative Examples 1 to 6 were prepared. In Comparative Example 6, the transparent resin layer was a single layer. The indentation hardness of the transparent resin layer was adjusted by changing the blending of the resin and the cooling temperature at the time of extrusion.

Example 6
Polypropylene was extruded by a coextrusion method using a T-die extruder to form a backer layer. The thickness of the backer layer was 0.25 mm. A urethane-based adhesive layer was further formed on the surface of the back surface primer layer of the decorative sheet produced in Example 1, and a backer layer was laminated on the surface of the urethane-based adhesive layer by a dry laminating method to prepare a decorative sheet. .. The thickness of the decorative sheet was 0.41 mm.

(Making decorative materials)
A urethane-modified ethylene-vinyl acetate emulsion adhesive is uniformly applied on a Lauan plywood having a thickness of 11.5 mm at 100 g / m ² wet, a decorative sheet is attached, and the mixture is cured at room temperature for 3 days to make up. The material was prepared.

(Evaluation method)
The following tests were conducted using the decorative materials prepared in Examples and Comparative Examples.

[1] Scratch resistance test (Hoffman scratch test)
The test was carried out using a Hoffman scratch tester manufactured by BYK-GARDNER in the United States. Specifically, a scratch blade (a cylindrical blade having a diameter of 7 mm) was set so as to come into contact with the surface of the decorative sheet of the decorative material at an angle of 45 °, and the testing machine was moved on the decorative material. The load (weight) was gradually increased by a load of 100 g, and the test was repeated until scratches, indentations, etc. were generated on the surface of the decorative sheet. Evaluation was made according to the following evaluation criteria. If the evaluation is ++, it is evaluated that there is no problem in actual use.
++: The initial scratch load is 1000 g or more. +: The initial scratch load is 700 to 900 g.-: The initial scratch load is 600 g or less.

[2] Impact resistance test (DuPont impact test)
According to the JISK5600-5-3 (1999) DuPont impact test, a shooting mold with a hemispherical tip with a radius of 6.3 mm was placed on the surface of the decorative sheet of the decorative material obtained in Examples and Comparative Examples. Then, a weight having a load of 500 g was dropped on the shooting mold from heights of 10 cm, 20 cm, 30 cm, 40 cm, and 50 cm. Evaluation was made according to the following evaluation criteria. The measurement was carried out under the temperature conditions of the decorative sheet of the decorative material at room temperature (25 ° C.) and 10 ° C. Further, in Table 1, when the sheet is not cracked even if it is dropped from 50 cm, it is described as> 50. If the evaluation is + or higher, there is no problem in actual use in cold regions, but if the evaluation is ++, it is evaluated to be particularly preferable.
++: The height of the weight at which the sheet cracks occur is 40 cm, or the sheet crack does not occur +: The height of the weight at which the sheet crack occurs is 20 cm or 30 cm-: The weight at which the sheet crack occurs The height is 10 cm

[3] Crack evaluation during bending (V-cut aptitude test)
A V-shaped groove is made on the surface opposite to the surface on which the decorative sheet of the decorative material is laminated, and the decorative material is bent at a right angle starting from the groove at room temperature (that is, the decorative sheet surface is mountain-folded and woody. The decorative material was bent at a right angle so that the base material surface was folded in a valley), and the state of cracking of the bent portion of the decorative sheet in the decorative material was visually observed. Evaluation was made according to the following evaluation criteria. The measurement was carried out under the temperature conditions of the decorative sheet of the decorative material at room temperature (25 ° C.) and 10 ° C.
++: There is no change in the appearance of the bent part of the decorative sheet, or there is a slight change but no cracks have occurred. +: The bent part of the decorative sheet has been whitened, but cracks have occurred. No-: There is a crack in the bent part of the decorative sheet.

[4] Moist heat resistance test (JAS moist heat test)
The decorative material is fixed horizontally, boiling water is dropped on the surface of the decorative material, a 1 L capacity aluminum container containing 0.5 L of boiling water is left on it for 20 minutes, and then rubbed with a dry cloth. , Left as it was for 24 hours. Next, the presence or absence of a change in the appearance of the place where the aluminum container of the decorative material was placed was visually observed. Evaluation was made according to the following evaluation criteria.
+: No trace of aluminum container was seen-: Trace of aluminum container was seen

[5] Indentation hardness The indentation hardness of the first transparent resin layer and the second transparent resin layer is measured by the micro region mechanical property evaluation device Tribo Indenter (registered trademark) "TI-950" (manufactured by HYSITRON). Was measured by the following measuring method.

(1) As the indenter of the nano indenter, a Berkovich indenter (model number: TI0039) having a triangular pyramid shape shown in FIG. 2 (a) was used. As shown in FIG. 2 (b), the Berkovich indenter is pushed into the measurement sample under the pushing conditions described later, and the pushing depth h (nm) with respect to the pushing load F (μN) is continuously measured, and FIG. 2 (c) shows. A load-displacement curve was created as shown. _{The maximum indentation load F max} (μN) was obtained from the created load-displacement curve. Next, the hardness was determined by dividing the maximum pushing load F _max (μN) by the contact projected area Ap (μm ^{2) between the indenter and the sample at that time.} Here, Ap is a contact projection area in which the indenter tip curvature is corrected by the apparatus standard method using the fused silica of the standard sample.
That is, H _IT = F _max / Ap.
(2) The pushing conditions are as shown in FIG. 2 (c) at room temperature (23 ± 5 ° C.), where a load of 0 to 50 μN is first applied in 5 seconds (that is, 10 μN / s), and then 50 μN (F). _{It was} held for 5 seconds under a load of max), and finally unloading from 50 to 0 μN was performed in 5 seconds.
(3) When measuring the hardness, the hardness of the cross section of the layer to be measured was measured in order to avoid the influence of the hardness of the layers other than the layer as the measurement sample. That is, the decorative sheet is embedded with a resin (normal temperature curing type epoxy two-component curing resin), left at room temperature for 24 hours or more to be cured, and then the cured embedded sample is prepared with a sharp knife (for example, an electron microscope section preparation). The sample is carved out so that the Berkovich indenter can be pushed in, and the cross section of the layer to be measured is exposed. The hardness of the cross section was measured by pushing the Berkovich indenter into the position where the fine particles were avoided). (4) The indentation hardness of 10 or more points was measured for the layer to be measured, and the average value of the 10 points measured with good reproducibility was used as the measured value.

The results are shown in Table 1.

1. 1. Decorative sheet 11. Surface protective layer 12. Transparent resin layer 121. First transparent resin layer 122. Second transparent resin layer 13. Pattern pattern layer 14. Base sheet 15. Backer layer 2. Cosmetic material 3. Adhesive material 20. Measurement sample 21. Berkovich indenter 22. Direction to apply load h. Pushing depth

Claims (7)

A decorative sheet having at least a transparent resin layer under the surface protective layer.
(1) The transparent resin layer has a first transparent resin layer and a second transparent resin layer in order from the surface protection layer side.
(2) The first transparent resin layer has a thickness of 10 μm or more and less than 20 μm, and an indentation hardness of 80 MPa or more.
(3) The second transparent resin layer has a thickness of 35 μm or more and an indentation hardness of 40 MPa or more and 70 MPa or less.
(4) The first transparent resin layer and the second transparent resin layer contain a polypropylene resin and contain a polypropylene resin.
(5) The total thickness of the first transparent resin layer and the thickness of the second transparent resin layer is 60 μm or more.
A decorative sheet characterized by that. The decorative sheet according to claim 1, wherein the transparent resin layer further has a third transparent resin layer under the second transparent resin layer. The decorative sheet according to claim 1 or 2, which has an embossed shape on the surface protective layer side. The decorative sheet according to any one of claims 1 to 3, wherein the surface protective layer contains an ionizing radiation curable resin or a two-component curable urethane resin. The decorative sheet according to any one of claims 1 to 4, wherein the surface protective layer contains an antiviral agent. The decorative sheet according to any one of claims 1 to 5, further comprising a transparent adhesive layer, a pattern layer, and a base material sheet under the transparent resin layer. A decorative material having the decorative sheet according to any one of claims 1 to 6 on an adherend.

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