JP2024109438A - Decorative sheets and decorative materials - Google Patents

Abstract

To provide a decorative sheet which can achieve both weather resistance and thermal peeling resistance, and a decorative material using the same.SOLUTION: A decorative sheet includes a base material sheet, an anchor coat layer provided on the base material sheet, and a transparent resin layer which is stacked on the anchor coat layer and contains a polypropylene resin. The transparent resin layer includes at least a resin layer A which contains a polypropylene resin and a hindered amine-based radical scavenger and is in contact with the anchor coat layer. The radical scavenger has an alkyl group represented by CH3(CH2)n- (in the formula, n represents an integer of 10 or more) and has a molecular weight of 1,000 or more.SELECTED DRAWING: Figure 1

Description

This disclosure relates to decorative sheets and decorative materials.

A base sheet with a printed pattern is used as a component of the decorative sheet, and it is common to further laminate a transparent resin layer made of a transparent resin material on top of the base sheet to improve the design. In recent years, from the perspective of environmental protection, decorative sheets in which the transparent resin layer is made of a resin material such as polypropylene resin have also been proposed (see, for example, Patent Document 1 below).

Since decorative sheets are sometimes used in outdoor exposure conditions, UV absorbers, light stabilizers, antioxidants, etc. are added to the transparent resin layer as weather resistance agents to give it weather resistance.

JP 2010-158798 A

The base sheet and the transparent resin layer are usually bonded via an anchor coat layer provided on the base sheet, but if the adhesive strength at the lamination interface is insufficient, for example, when masking tape or poster display tape is applied to the surface and the tape is peeled off after use, the transparent resin layer may peel off. In addition, when attaching a decorative sheet to various substrates, a hot melt wrapping adhesive may be used, but decorative sheets that have been subjected to stress due to such a thermal history tend to be more susceptible to the above-mentioned peeling problems.

In the past, resin materials containing polypropylene resin have been investigated for transparent resin layers with the aim of suppressing the decrease in peel strength after thermal history, but the inventors of the present disclosure have found that in heated decorative sheets, there is a decrease in peel strength due to the light stabilizer.

This disclosure has been made in consideration of the above circumstances, and aims to provide a decorative sheet that can achieve both weather resistance and heat-resistant peel strength, and a decorative material using the same.

In order to solve the above problems, the present disclosure provides the following decorative sheets and decorative materials.

[1] A decorative sheet comprising a base sheet, an anchor coat layer provided on the base sheet, and a transparent resin layer containing a polypropylene resin laminated on the anchor coat layer, the transparent resin layer containing a polypropylene resin and a hindered amine-based radical scavenger, the sheet including at least a resin layer A in contact with the anchor coat layer, the radical scavenger having an alkyl group represented by _CH3 ( _CH2 ) _n- (wherein n is an integer of 10 or more) and having a molecular weight of 1000 or more.
[2] The decorative sheet according to the above-mentioned [1], wherein the radical scavenger has a structure represented by the following general formula (1):

[In formula (1), n represents an integer of 10 or more, and m represents an integer.]
[3] The decorative sheet according to the above-mentioned [1] or [2], wherein the resin layer A further contains an ethylene-based elastomer.
[4] The decorative sheet according to the above-mentioned [3], wherein the transparent resin layer has a laminated structure of two or more layers, and the transparent resin layer includes a resin layer B that contains a polypropylene resin and does not contain an ethylene-based elastomer.
[5] The decorative sheet according to the above [4], wherein the thickness of the resin layer A is 5 to 30 μm.
[6] The decorative sheet according to any one of the above [3] to [5], wherein the ethylene-based elastomer is a polymer produced using a metallocene catalyst.
[7] The decorative sheet according to any one of the above [1] to [6], wherein the resin layer A further contains an acid-modified polypropylene resin.
[8] The decorative sheet according to the above-mentioned [7], wherein the acid-modified polypropylene resin is a maleic anhydride-modified polypropylene resin.
[9] A decorative material comprising a substrate and the decorative sheet according to any one of [1] to [8] above bonded to the substrate.

In the decorative sheet of the present disclosure, the transparent resin layer has sufficient weather resistance, and even after being subjected to a thermal history, the peel strength near the lamination interface between the transparent resin layer and the anchor coat layer can be sufficiently maintained. The inventor of the present disclosure speculates as follows about the reason for such an effect. In the decorative sheet described in [1] above, the radical scavenger contained in the resin layer A in contact with the anchor coat layer has the specific alkyl group described above, which improves compatibility with the polypropylene resin, and also has a high molecular weight, which makes it less likely to bleed out from the resin layer even when heated, and it is believed that this has enabled both weather resistance and heat-resistant peel strength to be achieved.

According to the decorative sheet according to [2] above, the above-mentioned effects are easily obtained. According to the decorative sheet according to [3] above, the polypropylene resin and the ethylene-based elastomer form a sea-island structure, which allows the peel stress to be absorbed more effectively, making it easier to obtain interlayer strength. According to the decorative sheet according to [4] above, the resin transparent layer can be further provided with functions such as scratch resistance. According to the decorative sheet according to [5] above, weather resistance can also be provided to the resin layer B, making it easy to improve the weather resistance, weather-resistant peel strength, and heat-resistant peel strength in a well-balanced manner. According to the decorative sheet according to [6] above, the ethylene-based elastomer is less likely to become low molecular weight over time, making it easier to suppress the decrease in adhesion of the resin layer A over time. According to the decorative sheets according to [7] to [8] above, the peel strength and heat-resistant peel strength can be further improved. The decorative material according to [9] above is laminated with the decorative sheet according to any one of [1] to [8] above, so that the design of the decorative sheet is less likely to deteriorate even when exposed to the outdoors, and the heat-resistant peel strength near the lamination interface between the transparent resin layer and the anchor coat layer can be sufficiently maintained.

This disclosure makes it possible to provide a decorative sheet that achieves both weather resistance and heat-resistant peel strength, and a decorative material using the same.

FIG. 1 is a schematic cross-sectional view showing one embodiment of a decorative sheet of the present disclosure.

Embodiments of the present disclosure are described in detail below.

<Decorative sheet>
The cosmetic sheet of the present embodiment includes a base sheet, an anchor coat layer provided on the base sheet, and a transparent resin layer containing a polypropylene resin laminated on the anchor coat layer.

Figure 1 is a schematic cross-sectional view showing one embodiment of the decorative sheet of the present disclosure. The decorative sheet 100 shown in Figure 1 comprises a patterned substrate sheet 1, an anchor coat layer 2 provided on the surface of the patterned substrate sheet 1, and a transparent resin layer 3 containing a polypropylene resin laminated on the anchor coat layer 2. The patterned substrate sheet 1 has a substrate sheet 11 and a pattern layer 12 provided on the surface of the substrate sheet 11 on the transparent resin layer 3 side. The transparent resin layer 3 has a two-layer laminate structure and includes a resin layer A31 that contacts the anchor coat layer 2 and a resin layer B32 that does not contact the anchor coat layer 3. The transparent resin layer 3 may have a laminate structure of three or more layers, or may be a single layer consisting of the resin layer A31.

The transparent resin layer 3 is mainly provided to protect the pattern layer 12 of the decorative sheet, improve the design, and exhibit scratch resistance, abrasion resistance, and chemical resistance, and is made of a constituent material mainly made of polypropylene resin. Examples of polypropylene resin include homopolypropylene obtained by polymerizing propylene alone, and propylene copolymers obtained by copolymerizing propylene as the main raw material with ethylene and one or more α-olefins having 4 to 20 carbon atoms. Examples of the α-olefins having 4 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-nonadecene, 1-eicosene, and 4-methyl-1-pentene.

The melting point of the homopolypropylene may be 120 to 170°C, 140 to 170°C, or 150 to 170°C. In order to increase the melting point or softening point, the homopolypropylene may be a polymer polymerized with a Ziegler-Natta catalyst. The homopolypropylene may contain an atactic polypropylene component, a syndiotactic polypropylene component, an isotactic polypropylene component, or two or more of these components.

The propylene copolymer may be, for example, a block copolymer such as a propylene-ethylene block copolymer, or a random copolymer such as a propylene-α-olefin random copolymer.

The propylene copolymer may contain 80 parts by mass or more, or 90 parts by mass or more, of the propylene component per 100 parts by mass of the total copolymerization components.

The transparent resin layer 3 may be colored or cloudy, as long as the printed pattern can be seen.

The transparent resin layer 3 includes at least a resin layer A31 that is in contact with the anchor coat layer 2. The resin layer A contains a polypropylene resin (hereinafter also referred to as component (A)) and a hindered amine-based radical scavenger.

The above-mentioned components can be used as component (A), and one can be used alone or two or more can be used in combination.

From the viewpoint of roll release properties, resin layer A may contain homopolypropylene (hereinafter also referred to as component (A1)).

The above-mentioned compounds can be used as component (A1), and one compound can be used alone or two or more compounds can be used in combination.

The (A1) component may be a commercially available product such as E2000GV (product name, manufactured by Prime Polymer Co., Ltd.), F113G (product name, manufactured by Prime Polymer Co., Ltd.), or FL03H (product name, manufactured by Japan Polypropylene Corporation).

The content of the (A1) component in the resin layer A may be 5 to 30 parts by mass, or 5 to 15 parts by mass, relative to 100 parts by mass of the total amount of the (A) component contained in the resin layer A.

The resin layer A may contain a propylene copolymer (hereinafter also referred to as component (A2)) from the viewpoint of suppressing whitening when folded. The above-mentioned components can be used as the component (A2), and one type can be used alone or two or more types can be used in combination.

The resin layer A may contain random polypropylene (hereinafter also referred to as component (A2-1)) as component (A2).

The above-mentioned propylene-α-olefin random copolymer can be used as component (A2-1), and one type can be used alone or two or more types can be used in combination.

From the viewpoint of film formation stability, the MFR(230) of the (A2-1) component may be 3 to 30 or 5 to 20.

The (A2-1) component may have a boiling heptane soluble residue of 50% or more, 60% or more, or 70% or more after curing at 40°C for 3 days.

In this specification, the boiling heptane soluble residue is measured by the following test.
(1) 2 g of a sample polymer is added to 200 ml of p-xylene, and the temperature is raised to 120° C. with stirring in an oil bath. Stirring is then continued for an additional 30 minutes to completely dissolve the polymer and prepare a homogeneous solution.
(2) Next, the p-xylene solution is left in a powered off oil bath for 24 hours and slowly cooled to room temperature (23°C) to precipitate a polymer. The p-xylene solution containing the polymer precipitate is poured into 2000 ml of methanol and stirred for 4 hours, after which the polymer precipitate is filtered off and dried under reduced pressure at 70°C for 24 hours.
(3) 1 g of the dried polymer powder is packed into a thimble and extracted with n-heptane for 7 hours using a Soxhlet extractor, after which the extraction residue is dried together with the thimble under reduced pressure at 70°C for 24 hours.
(4) Measure the dry weight before and after extraction, and calculate the boiling heptane soluble residue according to the following formula.
Boiling heptane soluble residue (%) = (dry weight after extraction) x 100 / (dry weight before extraction)

The samples used in the above tests were prepared by injection molding a specimen (size: 2mm x 2mm x 2mm) at 200°C and curing it in a constant temperature oven in the dark in the atmosphere at 40°C for three days.

The density of the (A2-1) component may be 890 to 910 kg/ ^m3 , or 895 to 910 kg/ ^m3 .

The (A2-1) component may be a commercially available product such as Prime Polypro S235WC (trade name, manufactured by Prime Polymer Co., Ltd.) or Y-2045GP (trade name, manufactured by Prime Polymer Co., Ltd.).

The content of the (A2-1) component in the resin layer A may be 10 to 70 parts by mass, or 40 to 50 parts by mass, relative to 100 parts by mass of the total amount of the (A) component contained in the resin layer A.

The resin layer A may contain a propylene-based elastomer (hereinafter also referred to as the (A2-2) component) as the (A2) component.

The component (A2-2) may be a propylene copolymer obtained by copolymerizing propylene as the main raw material with ethylene and one or more α-olefins having 4 to 20 carbon atoms. Examples of α-olefins include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-nonadecene, 1-eicosene, and 4-methyl-1-pentene. These can be used alone or in combination of two or more.

The propylene copolymer used as component (A2-2) may contain 60 parts by mass or more, or 70 parts by mass or more, of the propylene component per 100 parts by mass of the total amount of the copolymerization components.

From the viewpoint of film formation stability, the MFR(230) of the (A2-2) component may be 20 to 40 or 25 to 35.

The (A2-2) component may have a boiling heptane soluble residue of 30% or less, 20% or less, or 10% or less after curing at 40°C for 3 days.

The (A2-2) component may be a polymer produced using a metallocene catalyst. Resin layer A containing such an (A2-2) component can improve weather resistance because (A2-2) is less likely to become low molecular weight over time.

Examples of polymers using metallocene catalysts include copolymers of propylene with ethylene, butene, hexene, or octene.

The density of (A2-2) may be 865 to 910 kg/ ^m3 , or 868 to 910 kg/ ^m3 .

The (A2-2) component may be a commercially available product such as Catalloy (trade name, manufactured by Sunallomer Co., Ltd.), Tafmer PN-20300 (trade name, manufactured by Mitsui Chemicals, Inc.), or Tafthren (trade name, manufactured by Sumitomo Chemical Co., Ltd.).

The content of the (A2-2) component in the resin layer A may be 5 to 25 parts by mass, or 10 to 20 parts by mass, relative to 100 parts by mass of the total amount of the (A) component contained in the resin layer A.

The hindered amine radical scavenger has an alkyl group represented by CH ₃ (CH ₂ ) _n - (wherein n is an integer of 10 or more) and has a molecular weight of 1000 or more (hereinafter, may be referred to as "polymeric alkyl HALS"). From the viewpoint of compatibility with polypropylene resin, n may be 10 to 20 or may be 10 to 15. From the viewpoint of suppressing bleed-out, the molecular weight may be 3000 to 4000 or may be 3500 to 4000.

As the polymeric alkyl HALS, for example, a compound having a structure represented by the following general formula (1) can be used.

In formula (1), n is an integer of 10 or more, and m is an integer. Furthermore, n and m in formula (1) may be set so as to satisfy the above-mentioned conditions.

The compound having the structure represented by the above general formula (1) may be a commercially available product such as Uvinul 5050H (product name, manufactured by BASF Japan Ltd.).

The polymeric alkyl HALS can be used alone or in combination of two or more types.

The content of the polymeric alkyl HALS in resin layer A may be 0.1 to 0.5 mass%, 0.2 to 0.3 mass%, or 0.2 to 0.25 mass%, based on the total mass of resin layer A.

The resin layer A may further contain an ethylene-based elastomer (hereinafter also referred to as component (B)) in order to improve interlaminar strength.

The (B) component may be an ethylene copolymer obtained by copolymerizing ethylene as the main raw material with one or more α-olefins having 3 to 20 carbon atoms. Examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-nonadecene, 1-eicosene, and 4-methyl-1-pentene. The (B) component may be an ethylene copolymer obtained by copolymerizing ethylene with one or more α-olefins having 4 to 6 carbon atoms.

Component (B) may be used alone or in combination of two or more types.

The ethylene copolymer used as component (B) may contain 60 parts by mass or more, or 70 parts by mass or more, of the ethylene component per 100 parts by mass of the total copolymerization components.

From the viewpoint of peel strength during film formation, component (B) may have an MFR(190) of 1 or less, 0.4 to 0.8, or 0.4 to 0.6.

From the viewpoint of reducing the peel stress, the density of the (B) component may be 870 kg/ ^m3 or less, or may be 860 to 865 kg/ ^m3 .

The (B) component may be a polymer using a metallocene catalyst. Since the resin layer A containing such a (B) component contains a small amount of low molecular weight substances in the (B) component, it is easier to suppress the decrease in adhesion strength of the resin layer A over time.

Component (B) may be a commercially available product such as Tafmer DF605 (manufactured by Mitsui Chemicals, Inc., trade name, MFR: 0.5 (190°C)), Excellen VL100 (manufactured by Sumitomo Chemical Co., Ltd., trade name, MFR: 0.8 (190°C)), or Excellen VL102 (manufactured by Sumitomo Chemical Co., Ltd., trade name, MFR: 0.9 (190°C)).

The contents of the (A) and (B) components in the resin layer A may be 35 to 97 parts by mass and 3 to 65 parts by mass, or 70 to 80 parts by mass and 20 to 30 parts by mass, respectively, when the total content of the (A) and (B) components is 100 parts by mass.

When resin layer A contains the (A2-1) component and the (B) component, the contents of the (A2-1) component and the (B) component may be 15 to 99 parts by mass and 1 to 85 parts by mass, or 25 to 35 parts by mass and 65 to 75 parts by mass, respectively, when the total content of the (A2-1) component and the (B) component is taken as 100 parts by mass.

The resin layer A may further contain a resin component (hereinafter also referred to as component (C)) other than the above-mentioned components (A) and (B).

As component (C), a modifier can be used, and from the viewpoint of further improving the heat-resistant peel strength, for example, a polypropylene resin having a functional group introduced therein, such as an acid-modified polypropylene resin, can be used. The functional group may be introduced by graft polymerization, and for example, a maleic anhydride-modified polypropylene resin in which maleic anhydride is added to polypropylene can be used.

Component (C) may be used alone or in combination of two or more types.

The content of component (C) in resin layer A may be 1 to 10 parts by mass, or 1 to 5 parts by mass, when the total amount of polypropylene resin contained in resin layer A is 100 parts by mass.

The resin layer A may contain, as necessary, a heat stabilizer, a flame retardant, an ultraviolet absorber, a light stabilizer other than the above-mentioned high molecular alkyl HALS, a nucleating agent, an antiblocking agent, a catalyst capture agent, and the like.

The thickness of resin layer A may be 5 μm or more, or 10 μm or more, from the viewpoint of peel strength, and may be 30 μm or less, or 20 μm or less, from the viewpoint of scratch resistance.

When the transparent resin layer has a laminated structure of two or more layers and the anchor coat layer is in contact with the resin layer A, the thickness of the resin layer A may be 5 to 30 μm or 10 to 20 μm from the viewpoint of improving the weather resistance, weather resistant peel strength, and heat resistant peel strength of the transparent resin layer in a well-balanced manner.

The transparent resin layer 3 may further include a resin layer B32 that is not in contact with the anchor coat layer 2. In this case, the resin layer A ensures peel strength and heat-resistant peel strength, while further imparting functions such as scratch resistance to the resin transparent layer.

From the viewpoint of solvent resistance and heat resistance, the resin layer B may contain a polypropylene resin and may not contain an ethylene-based elastomer. In this case, homopolypropylene or random polypropylene may be used as the polypropylene resin, and homopolypropylene may be used from the viewpoint of scratch resistance. As the homopolypropylene, for example, commercially available products such as E2000GV (manufactured by Prime Polymer Co., Ltd., product name), Prime Polypro Y-2000GP (manufactured by Prime Polymer Co., Ltd., product name), and F113G (manufactured by Prime Polymer Co., Ltd., product name) may be used.

Examples of ethylene-based elastomers not included in resin layer B include those that contain 30% or more of components with a molecular weight of 1,000 or less.

The content of polypropylene resin in resin layer B may be 88% by mass or more, or 90% by mass or more, based on the total mass of resin layer B.

The resin layer B may contain heat stabilizers, flame retardants, ultraviolet absorbers, light stabilizers, nucleating agents, antiblocking agents, catalyst scavengers, etc. as necessary.

The thickness of resin layer B may be 50 μm or more, or 60 μm or more, from the viewpoint of scratch resistance, and may be 80 μm or less, or 75 μm or less, from the viewpoint of post-processing such as V-cut processing and wrapping processing.

The above-mentioned resin layer A and resin layer B may be laminated, and the laminated product may be laminated on top of the base sheet by known methods such as dry lamination and sand lamination. However, by using the hot melt co-extrusion lamination method using a T-die, various advantages can be obtained. For example, it is not necessary to provide an adhesive layer between resin layer A and resin layer B that are in contact with the anchor coat layer, and the laminate of resin layer A and resin layer B that are in contact with the anchor coat layer and the base sheet can be laminated simultaneously, enabling efficient production. Furthermore, when performing co-extrusion lamination, a pattern that is the inverse of the concave and convex shape of the design shape to be imparted to the decorative sheet can be imparted to the surface of the decorative sheet at the same time by imparting to the cooling roll a pattern that is the inverse of the concave and convex shape of the design shape to be imparted to the decorative sheet.

Non-vinyl chloride resin materials can be used as the constituent material of the anchor coat layer 2. For example, a two-component curing urethane resin that forms a urethane bond by reaction between a polyol and an isocyanate, or a hydroxyl group-modified polyolefin can be used. Examples of the polyol component include polyester polyol and polyester polyurethane polyol. These may be used alone or in combination of two or more. Examples of the isocyanate component include hexamethylene diisocyanate and isophorone diisocyanate. These may be used alone or in combination of two or more.

The thickness of the anchor coat layer 2 may be 0.1 μm or more, or 0.5 μm or more, from the viewpoint of adhesion, and may be 10 μm or less, or 5 μm or less, from the viewpoint of peel strength. The thickness of the anchor coat layer is calculated by dividing the coating weight (unit: grams/m2) by the specific gravity of the ink.

Methods for forming the anchor coat layer 2 include the gravure method (gravure printing method, gravure coating method), etc. In this embodiment, the anchor coat layer 2 can be formed by the gravure coating method, etc. on the side of the patterned substrate sheet 1 on which the pattern layer 12 is provided.

As the base sheet 11, sheets containing non-vinyl chloride resin materials such as polypropylene, polyethylene, ethylene-vinyl acetate copolymer resin, ethylene-vinyl alcohol copolymer resin, polystyrene, ABS, polymethyl methacrylate, polymethyl acrylate, polybutyl acrylate, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl acetal, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyurethane, polyamide, nylon 6, and nylon 66 can be used.

From the viewpoint of recyclability, the base sheet 11 may be a base sheet made of a polyolefin material such as polypropylene or polyethylene. Also, from the viewpoint of increasing the content ratio of polypropylene-based materials in the decorative sheet, the base sheet 11 may be a base sheet made of polypropylene resin.

The resin constituting the base sheet 11 may contain one or more additives, such as inorganic pigments, antioxidants, light stabilizers, and antiblocking agents, in appropriate amounts.

The base sheet 11 may be given a concealing property. The reason for providing the concealing property is to prevent the base material, such as a wood board, an inorganic board, or a metal plate, that is to be attached from being seen from the surface of the decorative sheet. However, this is not the case when it is desired to make use of the texture of the base material.

The concealing properties (concealing layer) and the pattern layer 12 may be imparted to the substrate sheet 11 by a known printing method such as gravure printing, intaglio printing, flexographic printing, silk printing, electrostatic printing, inkjet printing, etc., on the front or back surface of the substrate sheet 11, or on both surfaces. The ink used in this case may be a known ink, for example, an ink obtained by adding a colorant such as a dye or pigment, an extender pigment, etc. to a vehicle, and further adding a plasticizer, a stabilizer, wax, grease, a drying agent, a hardener, a thickener, a dispersant, a filler, etc., and thoroughly kneading the ink with a solvent, a diluent, etc.

Also, a method can be used in which the concealing layer or the pattern layer, or both, are formed on an arbitrary transfer base sheet other than the base sheet 11 by the above-mentioned formation method or the like, and the transfer base sheet is then attached to the base sheet 11 by a thermal lamination method, a dry lamination method, a wet lamination method, an extrusion lamination method or the like, and then the transfer base sheet is peeled off to transfer the concealing layer or the pattern layer, or both, onto the base sheet 11.

In addition, when the T-die extrusion method is used as the manufacturing method of the base sheet 11, the synthetic resin material for forming the film may be directly colored with a coloring agent having hiding properties such as a dye or pigment, and extruded from the T-die in a heated and molten state, and the obtained base sheet 11 may be colored to impart hiding properties. In this case, the coloring method of the base sheet 11 in the T-die extrusion method includes, but is not limited to, the dry color method and the master batch method. The dry color method is a method in which a fine powder coloring agent in which a pigment is treated with a dispersing agent or a surfactant is directly mixed into an uncolored normal synthetic resin material for forming the base sheet 11. On the other hand, the master batch method is a method in which a master batch pellet is prepared in advance by melt-kneading an uncolored normal synthetic resin material for forming the base sheet 11 and a high concentration pigment to pre-disperse them, and the master batch pellet is dry-blended with the uncolored normal synthetic resin material for forming the base sheet 11 in the extrusion hopper.

Methods for applying a pattern layer to a base sheet include a method of applying it to the surface of the base sheet and a method of applying it to the base sheet itself (within the layer of the base sheet). The above-mentioned printing method and transfer method can be used as a method for applying it to the surface. A method for applying it to the base sheet itself includes a method in which a high concentration of pigment is melt-kneaded and pre-dispersed in a resin with different flow characteristics from the resin constituting the base sheet, and the masterbatch pellets, wood powder, glass powder, etc. are added to the above-mentioned synthetic resin material that has been given hiding properties for forming a film of the base sheet, and the material is heated and melted, extruded, and formed into a film. This makes it possible to give a pattern using masterbatch pellets, wood powder, glass powder, etc. to the base sheet itself, which has hiding properties. These methods for giving coloring hiding properties and patterns to the base sheet itself can also be used in combination with the above-mentioned printing method and transfer method.

In addition, when using a calendar method to manufacture a base sheet with concealing properties, the base sheet can be given concealing properties and patterns by a similar method, that is, by manufacturing the base sheet by the calendar method while simultaneously imparting coloring concealing properties and patterns to the base sheet itself, or by a method that combines these methods with the printing method, transfer method, etc., described above.

The decorative sheet 100 comprises a patterned base sheet 1 having a pattern layer 12 provided on a base sheet 11, but may also comprise a base sheet 11 having at least one of a concealing layer and a pattern layer provided on the front or back surface, or both, of the front and back surfaces, or may comprise a base sheet in which the concealing properties or pattern are applied to the base sheet itself.

In the decorative sheet of this embodiment, in order to improve the feel of the surface of the decorative sheet and to further enhance the design, a recessed pattern may be formed in the transparent resin layer 3 (for example, the outermost layer such as resin layer B), and if necessary, a filler ink may be embedded in the recesses. In addition, the decorative sheet may be laminated with a surface protection layer as the outermost layer from the viewpoint of further enhancing the design and various physical properties.

The surface protection layer may be formed by any known technique, for example, by gravure coating, with a thickness of 3 to 20 μm. Materials that can be used include acrylic, ester, and urethane, and the curing type may be isocyanate-curable, ultraviolet-curable, or electron beam-curable, either alone or in a hybrid form.

In the decorative sheet of this embodiment, a primer coating layer may be laminated on the back surface of the decorative sheet to increase adhesion to wood-based, inorganic, and metal-based substrates.

The primer coat layer may be laminated using known techniques, for example, by gravure coating, to a thickness of 1 to 5 μm. As the material, an isocyanate-curing polyester material may be used. In addition, to prevent blocking when the decorative sheet is rolled up (a phenomenon in which overlapping decorative sheets adhere too closely to each other, making them difficult to peel off), an inorganic granular material such as silica with an average particle size of 1 to 10 μm may be added to the primer coat layer.

<Decorative materials>
The decorative material of the present embodiment comprises a substrate and the decorative sheet of the present embodiment attached to the substrate.

The substrate to which the decorative sheet is attached can be appropriately selected depending on the application and type of the decorative material, and examples of such substrates include inorganic (non-metallic), metallic, wood-based, and plastic-based materials.

Inorganic substrates include tiles and gypsum boards. Metal substrates include steel plates and aluminum plates. Wood substrates include MDF (medium density fiberboard) and plywood. Plastic substrates include polypropylene, PVC, polyester, acrylic, and styrene boards.

An adhesive may be used to bond the decorative sheet to the substrate. Examples of adhesives include hot melt adhesives, organic solvent adhesives, and water-based adhesives. The adhesive material may be urethane-based, ester-based, acrylic-based, vinyl acetate-based, etc.

The decorative material of this embodiment may be one in which a substrate and a decorative sheet are bonded together at high temperature via the adhesive described above, since the decorative sheet of this embodiment has excellent heat-resistant peel strength. The heating temperature may be 150°C or higher from the viewpoints of time saving and adhesive strength, and may be 180 to 250°C from the viewpoint of suppressing changes in the design of the decorative sheet (for example, maintaining the embossed uneven pattern).

The present disclosure will be explained in detail below with reference to examples, but the present disclosure is not limited to these examples.

<Preparation of decorative sheet>
(Examples 1 to 8)
A sheet was prepared by melt extruding a resin composition containing 93.3 parts by mass of random polypropylene resin, 6 parts by mass of inorganic pigment, 0.2 parts by mass of phenolic antioxidant, 0.3 parts by mass of hindered amine light stabilizer, and 0.2 parts by mass of antiblocking agent as a base sheet. After corona treatment was performed on the surface of this sheet, a wood grain pattern was applied by gravure printing using a pattern ink (V351 manufactured by Toyo Ink Co., Ltd.) to form a pattern layer.

Next, a two-component curing urethane anchor coating agent (Takelac A3210 (main agent, product name, manufactured by Mitsui Chemicals, Inc.) and Takenate A80 (hardening agent, product name, manufactured by Mitsui Chemicals, Inc.) mixed in a mass ratio of 8:1) was applied to the wood grain pattern layer by gravure printing to a thickness of approximately 1 μm to form an anchor coating layer.

Next, a single-layer transparent resin layer was laminated on the upper surface of the anchor coat layer by a T-die extrusion lamination method at an extrusion temperature of 230° C. using a blend of the materials shown in Table 1 in the compounding ratios (parts by mass) shown in the same table, so that the resin layer A and the anchor coat layer were in contact with each other, with an extrusion thickness shown in the same table. Next, the surface layer was corona-treated, and then a top coat agent (main agent: W480E Gloss UVH, hardener: W325N compounding ratio 100/10, both manufactured by DIC Graphics Corporation) was applied to the top coat agent at 6 g/m ₂ (after solvent evaporation) to prepare each decorative sheet.

(Examples 9 to 15 and Comparative Examples 1 to 3)
A sheet was prepared by melt extruding a resin composition containing 93.3 parts by mass of random polypropylene resin, 6 parts by mass of inorganic pigment, 0.2 parts by mass of phenolic antioxidant, 0.3 parts by mass of hindered amine light stabilizer, and 0.2 parts by mass of antiblocking agent as a base sheet. After corona treatment was performed on the surface of this sheet, a wood grain pattern was applied by gravure printing using a pattern ink (V351 manufactured by Toyo Ink Co., Ltd.) to form a pattern layer.

Next, a two-component curing urethane anchor coating agent (Takelac A3210 (main agent, product name, manufactured by Mitsui Chemicals, Inc.) and Takenate A80 (hardening agent, product name, manufactured by Mitsui Chemicals, Inc.) mixed in a mass ratio of 8:1) was applied to the wood grain pattern layer by gravure printing to a thickness of approximately 1 μm to form an anchor coating layer.

Next, a transparent resin layer having a two-layer structure of resin layer A and resin layer B was laminated on the upper surface of the anchor coat layer by blending the materials shown in Table 2 or Table 3 in the compounding ratio (parts by mass) shown in the same table to the extrusion thickness shown in the same table at an extrusion temperature of 230° C. by a T-die coextrusion lamination method so that resin layer A and the anchor coat layer were in contact. Next, the surface layer was subjected to a corona treatment, and then a top coat agent (main agent: W480E Gloss UVH, hardener: W325N compounding ratio 100/10, both manufactured by DIC Graphics Corporation) was applied to 6 g/m ₂ (after solvent evaporation) to prepare each decorative sheet.

(Example 16)
A decorative sheet was prepared in the same manner as above, except that the anchor coat layer was formed using UNISTOLE P-801 (manufactured by Mitsui Chemicals, Inc., product name), a hydroxyl group-modified polyolefin, instead of the two-component curing urethane anchor coat agent.

<Material evaluation method>
The boiling heptane soluble residue was measured by the following method.
(1) 2 g of a sample polymer is added to 200 ml of p-xylene, and the temperature is raised to 120° C. with stirring in an oil bath. Stirring is then continued for an additional 30 minutes to completely dissolve the polymer and prepare a homogeneous solution.
(2) Next, the p-xylene solution is left in a powered off oil bath for 24 hours and slowly cooled to room temperature (23°C) to precipitate a polymer. The p-xylene solution containing the polymer precipitate is poured into 2000 ml of methanol and stirred for 4 hours, after which the polymer precipitate is filtered off and dried under reduced pressure at 70°C for 24 hours.
(3) 1 g of the dried polymer powder is packed into a thimble and extracted with n-heptane for 7 hours using a Soxhlet extractor, after which the extraction residue is dried together with the thimble under reduced pressure at 70°C for 24 hours.
(4) Measure the dry weight before and after extraction, and calculate the boiling heptane soluble residue according to the following formula.
Boiling heptane soluble residue (%) = (dry weight after extraction) x 100 / (dry weight before extraction)

The samples used in the above tests were made by injection-molding the polymer (size: 2 mm x 2 mm x 2 mm) at 200°C, and curing it in a thermostatic oven in the dark in the atmosphere at 40°C for three days.

The decorative sheets produced in the examples and comparative examples were evaluated as follows:

[Peel strength (N/in) at 25°C]
A strip-shaped evaluation sample cut into a width of 1 inch from the decorative sheet was prepared, and a portion near the laminate interface (the interface between the resin layer A and the anchor coat layer) at one end of the sample was preliminarily peeled off using an organic solvent or the like, and a peel test was performed at a peel speed of 50 mm/min in an environment of 23° C. The peeling was performed by chucking the top and bottom of the partially peeled portion with a jig, and holding the unpeeled portion (the portion to be peeled) perpendicular to the movement direction of the chuck to form a T-shape.

[Peel strength after heating at 80° C. for 72 hours (N/in)]
A peel test was carried out in the same manner as in the measurement of peel strength in a 25° C. environment, except that the evaluation sample was heated in an oven at 80° C. for 72 hours.

[Peel strength after heating at 100° C. for 72 hours (N/in)]
A peel test was carried out in the same manner as in the measurement of peel strength in a 25° C. environment, except that the evaluation sample was heated in an oven at 100° C. for 72 hours.

[Peel strength after accelerated weathering test (N/in)]
The decorative sheet was placed in a Sunshine Weather weathering tester (black panel 63°C, 18 minutes of water spraying out of 120 minutes) and removed after a predetermined time (2000 hours). A peel test was performed on the decorative sheet after the test in the same manner as in the measurement of peel strength in a 25°C environment.

[Surface pencil hardness]
A test was conducted in which a pencil (Hi-uni, manufactured by Mitsubishi Pencil Co., Ltd.) whose tip had been flattened with abrasive paper was pressed against the surface of the decorative sheet at a speed of 0.8 mm/s for a distance of 7 mm. The hardness (pencil hardness) of the hardest pencil that did not leave a scratch on the surface of the decorative sheet was measured.

The details of the materials shown in Tables 1 to 3 are as follows:

(Resin Layer A)
Random polypropylene: Prime Polypro S235WC (product name, manufactured by Prime Polymer Co., Ltd.), MFR: 11 (230°C), boiling heptane soluble residue: 75%
Homopolypropylene: E2000GV (product name, manufactured by Prime Polymer Co., Ltd.)
Propylene-based elastomer a: Catalloy (trade name, manufactured by Sunallomer Co., Ltd.), MFR: 9.5 (230°C), boiling heptane dissolution residue: 46%
Propylene-based elastomer b: Toughmer PN-20300 (manufactured by Mitsui Chemicals, Inc., product name), MFR: 30 (230°C), boiling heptane soluble residue: 13%
Ethylene-based elastomer: Toughmer DF605 (manufactured by Mitsui Chemicals, Inc., product name), MFR: 0.5 (190°C), density: 861 kg/ ^m3
High molecular weight alkyl HALS: Uvinul 5050H (BASF Japan Ltd., trade name), molecular weight 3000 to 4000
Low molecular weight HALS: Tinuvun 765 (product name, manufactured by BASF Japan Ltd.), molecular weight 509
Polymeric HALS: Chimassorb 944 (product name, manufactured by BASF Japan Ltd.), molecular weight 2000 to 3100
Modifier: UMEX 1001 (product name, manufactured by Sanyo Chemical Industries, Ltd.)

(Resin Layer B)
Homopolypropylene: E2000GV (product name, manufactured by Prime Polymer Co., Ltd.)
Compound: A mixture of 90 parts by mass of E2000GV (trade name, manufactured by Prime Polymer Co., Ltd.), 5 parts by mass of Chimassorb 944 (trade name, hindered amine-based light stabilizer, manufactured by BASF Japan Ltd.), and 5 parts by mass of Tinuvin 326 (trade name, benzotriazole-based ultraviolet absorber, manufactured by BASF Japan Ltd.) was melt-mixed in a twin-screw extruder and pelletized.

(Anchor coat layer)
C1: Takelac A3210 (manufactured by Mitsui Chemicals, Inc., product name) (isocyanate-cured polyester system (mixed with Takenate A80 at an 8/1 ratio))
C2: Unistole P-801 (manufactured by Mitsui Chemicals, Inc., product name) (hydroxyl group-modified polyolefin)

1...Patterned base sheet, 2...Anchor coat layer, 3...Transparent resin layer, 11...Base sheet, 12...Pattern layer, 31...Resin layer A, 32...Resin layer B, 100...Decorative sheet.

Claims (9)

The present invention comprises a base sheet, an anchor coat layer provided on the base sheet, and a transparent resin layer including a polypropylene resin laminated on the anchor coat layer,
the transparent resin layer includes at least a resin layer A that contains a polypropylene resin and a hindered amine radical scavenger and is in contact with the anchor coat layer;
The decorative sheet, wherein the radical scavenger has an alkyl group represented by CH ₃ (CH ₂ ) _n - (wherein n is an integer of 10 or more) and has a molecular weight of 1,000 or more. The decorative sheet according to claim 1 , wherein the radical scavenger has a structure represented by the following general formula (1):

[In formula (1), n represents an integer of 10 or more, and m represents an integer.] The decorative sheet according to claim 1, wherein the resin layer A further contains an ethylene-based elastomer. The transparent resin layer has a laminated structure of two or more layers,
The decorative sheet according to claim 3 , wherein the transparent resin layer comprises a resin layer B that contains a polypropylene resin and does not contain an ethylene-based elastomer. The decorative sheet according to claim 4, wherein the thickness of the resin layer A is 5 to 30 μm. The decorative sheet according to claim 3, wherein the ethylene-based elastomer is a polymer produced using a metallocene catalyst. The decorative sheet according to claim 1, wherein the resin layer A further contains an acid-modified polypropylene resin. The decorative sheet according to claim 7, wherein the acid-modified polypropylene resin is a maleic anhydride-modified polypropylene resin. A decorative material comprising a substrate and a decorative sheet according to any one of claims 1 to 8 attached to the substrate.

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