JP2023122995A - Decorative sheet and method for producing decorative sheet - Google Patents

Abstract

The present invention provides a decorative sheet with excellent weather resistance, scratch resistance, and stain resistance, and a method for manufacturing the decorative sheet. A decorative sheet 10 according to the present embodiment includes a base layer 11 containing polyolefin, a pattern layer 12 formed on the base layer 11, and an anchor layer 13 formed on the pattern layer 12. A transparent resin layer 14 formed on the anchor layer 13 and mainly composed of polypropylene, and a top coat layer 15 formed on the transparent resin layer 14, the top coat layer 15 is made of polycarbonate-based urethane resin and carbodiimide. It is composed of a curing agent, an inorganic filler, a wax, an ultraviolet absorber, a light stabilizer, and an antibacterial agent. [Selection diagram] Figure 1

Description

TECHNICAL FIELD The present invention relates to a decorative sheet used for surfaces of interiors and exteriors of buildings, fittings, furniture, etc., and a method for producing the decorative sheet.

With the diversification of use environments in recent years, there is an increasing demand for higher functionality of decorative sheets. In general, it is difficult to improve all physical properties such as weather resistance, scratch resistance, and stain resistance at the same time. often When imparting weather resistance to this topcoat layer, it is common to add a weather resistance agent such as an ultraviolet absorber and a light stabilizer.

JP 2019-30998 A

Decorative sheets are also being used for exterior applications, and improvement in weather resistance is a particular issue. In order to improve the weather resistance, it is common to add weather resistance agents such as ultraviolet absorbers and light stabilizers to the top coat layer. In order to improve the weather resistance, it is common to increase the amount of these additives, but there is a possibility that physical properties such as scratch resistance and stain resistance of the topcoat layer may be lowered. That is, in conventional decorative sheets, there is a so-called trade-off relationship between improvement in weather resistance and improvement in scratch resistance and stain resistance.
The present invention specifies the material composition of the topcoat layer and minimizes the amount of the weathering agent used in combination to provide a decorative sheet having excellent weather resistance, scratch resistance, and stain resistance, and the production of the decorative sheet. We aim to provide a method.

The inventor found the present invention by studying the material composition used for the topcoat layer for the purpose of further improving the weather resistance, scratch resistance and stain resistance of the decorative sheet.
In order to solve the above problems, a decorative sheet according to one aspect of the present invention includes a polyolefin base material, a pattern layer formed on the polyolefin base material, an anchor coat layer formed on the pattern layer, A transparent resin layer formed on the anchor coat layer and containing polypropylene as a main component, and a top coat layer formed on the transparent resin layer, wherein the top coat layer comprises a polycarbonate-based urethane resin and carbodiimide. The gist of the composition is that it includes a curing agent, an inorganic filler, a wax, an ultraviolet absorber, a light stabilizer, and an antibacterial agent.

According to one aspect of the present invention, by specifying the material composition of the topcoat layer, the decorative sheet having excellent weather resistance, scratch resistance, and stain resistance without impairing other properties, and the production of the decorative sheet. can provide a method.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing explaining the structure of the decorative sheet which concerns on embodiment of this invention.

Next, embodiments of the present invention will be described with reference to the drawings. The descriptions in the drawings below are schematic, and the relationship between the thickness and the planar dimension, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined with reference to the following description.
Further, the embodiments shown below are examples of devices and methods for embodying the technical idea of the present invention. etc. are not specified below. Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

[Overall configuration of decorative sheet]
As shown in FIG. 1, a decorative sheet 10 according to an embodiment of the present invention (hereinafter referred to as the present embodiment) includes a base layer 11, a pattern layer 12, an anchor layer 13, a transparent resin layer 14, and a top coat. layer 15 and so on are laminated in this order. The configuration of each layer described above will be described below.

(Base material layer 11)
The base material layer 11 is a layer composed of a polyolefin base material, that is, a base material containing polyolefin, or a base material containing only polyolefin. Examples of the polyolefin forming the base material layer 11 include polyethylene, polypropylene, polybutylene, etc. Among them, polyethylene is most preferable. By making the base material layer 11 a layer composed of a polyolefin base material, it is possible to reduce the generation of harmful gases and the like at the time of disposal. Further, by using a layer composed of a base material containing polyethylene or a base material containing only polyethylene as the base material layer 11, it is possible to further reduce the generation of harmful gases and the like at the time of disposal.

The base material layer 11 is preferably a layer composed of a polyolefin base material as described above, but may be a layer composed of other materials. The base material layer 11 made of a material other than polyolefin will be described below.
As the base material layer 11, for example, a material selected arbitrarily from paper, synthetic resin, synthetic resin foam, rubber, non-woven fabric, synthetic paper, metal foil, and the like can be used. Examples of paper include thin paper, titanium paper, and resin-impregnated paper. Examples of synthetic resins include polystyrene, polycarbonate, polyester, polyamide, ethylene-vinyl acetate copolymer, polyvinyl alcohol, and acrylic. Examples of rubber include ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, styrene-butadiene copolymer rubber, styrene-isoprene-styrene block copolymer rubber, styrene-butadiene-styrene block copolymer rubber, polyurethane, and the like. I can give an example. Organic or inorganic nonwoven fabrics can be used as the nonwoven fabric. Examples of the metal of the metal foil include aluminum, iron, gold, and silver.
The substrate layer 11 may be subjected to surface treatment such as corona treatment, plasma treatment, ozone treatment, electron beam treatment, ultraviolet treatment, dichromic acid treatment, etc., in order to enhance adhesion with adjacent layers.

(Picture layer 12)
The pattern layer 12 is a pattern-printed layer applied to the base material layer 11 using ink.

The ink that forms the pattern layer 12 contains a binder, and the binder includes, for example, nitrocellulose, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, polyester, and the like, either alone or modified. It can be appropriately selected and used from among them. The binder may be water-based, solvent-based, or emulsion type, and may be either a one-liquid type or a two-liquid type using a curing agent. Furthermore, the pattern layer 12 may be formed by using a curable ink and curing the ink by irradiation with ultraviolet rays, electron beams, or the like. Among them, the most common method is a method of using urethane-based ink and curing the ink with isocyanate to form the pattern layer 12 .
In addition to the binder described above, the pattern layer 12 may contain pigments, colorants such as dyes, extender pigments, solvents, various additives, and the like, which are contained in ordinary inks. Examples of highly versatile pigments include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, and pearl pigments such as mica.

Curing agents used for curing urethane-based inks are not particularly limited. It can be used by appropriately selecting from commercially available curing agents such as

In addition to the application of ink, it is also possible to apply a design to the pattern layer 12 by vapor deposition or sputtering of various metals.
In addition, it is preferable that a light stabilizer is added to the above-described ink, so that deterioration of the decorative sheet 10 itself caused by light deterioration of the ink can be suppressed, and the life of the decorative sheet 10 can be extended. . In order to effectively suppress deterioration of the decorative sheet 10 itself caused by light deterioration of the ink, the content of the light stabilizer is set within a range of 1% by mass or more and 5% by mass or less with respect to the mass of the entire ink. preferably.

A method for forming the pattern layer 12 is not particularly limited. The picture layer 12 can be formed using a normal printing method such as gravure printing, offset printing, screen printing, flexographic printing, and inkjet printing.

(Anchor layer 13)
The anchor layer (anchor coat layer) 13 is a layer provided to enhance the adhesiveness between the pattern layer 12 and the transparent resin layer 14 .
The material constituting the anchor layer 13 is not particularly limited. It is possible to use a material in which a material having excellent adhesion to 14 is appropriately selected and made into an ink.

A method for forming the anchor layer 13 is not particularly limited. The anchor layer 13 can be formed using a normal coating method such as gravure coating, micro gravure coating, comma coating, knife coating, and die coating.

(Transparent resin layer 14)
The transparent resin layer 14 is a layer provided to improve the strength (mechanical strength) of the decorative sheet 10 as a whole.
The transparent resin layer 14 is a layer containing polypropylene as a main component. Here, the “main component” means that the mass of polypropylene accounts for 50 mass % or more of the mass of the entire transparent resin layer 14 .

The transparent resin layer 14 may contain resin components other than polypropylene. As materials other than polypropylene that can be included in the transparent resin layer 14, olefin resins are preferably used, and in addition to polyethylene, polybutene, etc., α olefins (eg, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4, 4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc.) Homopolymerization or copolymerization of two or more types, ethylene/vinyl acetate copolymer, ethylene/vinyl alcohol copolymer, ethylene/methyl methacrylate copolymer, ethylene/ethyl methacrylate copolymer, ethylene/butyl methacrylate copolymer polymers, ethylene/methyl acrylate copolymers, ethylene/ethyl acrylate copolymers, ethylene/butyl acrylate copolymers, and copolymers of ethylene or α-olefins with other monomers. .

Moreover, in order to improve the surface strength of the decorative sheet 10, it is preferable to use highly crystalline polypropylene as the resin constituting the transparent resin layer 14. FIG. In other words, it is preferable that the transparent resin layer 14 is a layer whose main component is highly crystalline polypropylene.

Moreover, the transparent resin layer 14 may contain, as weather resistance agents, an ultraviolet absorber having a triazine skeleton and a light stabilizer having a NOR type skeleton. The transparent resin layer 14 may contain, for example, a benzophenone-based ultraviolet absorber and a hindered amine-based light stabilizer as weather resistant agents. The benzophenone-based ultraviolet absorber is preferably in the range of 0.1 mass % or more and 5 mass % or less with respect to the mass of the entire transparent resin layer 14 . Moreover, the hindered amine light stabilizer is preferably in the range of 0.1 mass % or more and 5 mass % or less with respect to the mass of the entire transparent resin layer 14 .

Various additives such as heat stabilizers, light stabilizers, antiblocking agents, catalyst scavengers, colorants, light scattering agents and gloss modifiers may be added to the transparent resin layer 14 as necessary. . Phenolic, sulfur, phosphorus, and hydrazine heat stabilizers, and hindered amine light stabilizers are generally added in arbitrary combinations.

A method for forming the transparent resin layer 14 is not particularly limited. The transparent resin layer 14 can be formed using a normal method such as calendar film formation or extrusion film formation. Among them, extrusion molding is preferable as a method for forming the transparent resin layer 14 . In the case of extrusion molding, the transparent resin layer 14 can be formed uniformly.
In addition, the transparent resin layer 14 may be provided with surface irregularities in order to impart design properties. Examples of the method of providing unevenness include a method of subjecting the transparent resin layer 14 to heat embossing after extrusion molding, and a method of performing embossing simultaneously with extrusion molding using a cooling roll provided with unevenness during extrusion molding.

(Top coat layer 15)
The top coat layer 15 is a layer provided to impart functions such as weather resistance, scratch resistance, stain resistance, and design to the decorative sheet 10 .
The material constituting the top coat layer 15 is not particularly limited, and for example, an ionizing radiation curable resin or a thermosetting resin is preferably used.

As the ionizing radiation curable resin, for example, various monomers and commercially available oligomers can be used. It is preferable to use polyfunctional monomers such as triacrylate (TMPTA) and dipentaerythritol hexaacrylate (DPHA), polyfunctional oligomers such as Shikou UV-1700B (manufactured by Nippon Gosei Chemical Co., Ltd.), or mixtures thereof.

As the thermosetting resin, for example, one formed by thermally curing a polymer containing a carboxy group described below and a carbodiimide compound (carbodiimide curing agent) as a curing agent component is preferable. Polymers containing carboxyl groups are not particularly limited, but may be used, for example, to impart mechanical properties to the topcoat layer 15 by elongation of the molecular structure. The polymer containing a carboxyl group is appropriately selected and used from, for example, various acrylic polymers, various polyesters, various polyethers, various polycarbonates, various polyurethanes, and the like.

Polycarbonate-based urethane resin is the most preferable material for forming the top coat layer 15 among the resins described above. A polycarbonate-based urethane resin is a urethane resin having a polycarbonate diol as a structural unit and obtained by reaction with an isocyanate compound or a diol compound.

The carbodiimide compound that is a curing agent component is not particularly limited as described above, but examples include diisopropylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-3-dimethylamino Propyl-N'-ethylcarbodiimide, N-tert-butyl-N'-ethylcarbodiimide, N-cyclohexyl-N'-2-morpholinoethylcarbodiimide meso-p-toluenesulfonic acid, N,N'-di-tert- butylcarbodiimide, and the like.

The amount of the carbodiimide compound added is determined by the molar equivalent (mmol/g) of carbodiimide calculated from the carbodiimide equivalent (NCN equivalent) and the acid value (mgKOH/g) of the polycarbonate-based urethane resin, and the number of carboxyl groups in the polycarbonate-based urethane resin. The equivalent ratio to the molar equivalent (mmol/g) (molar equivalent of carbodiimide/molar equivalent of carboxy group in polycarbonate-based urethane resin) is preferably 1 or more, more preferably 1.2 or more, and 1 .3 or more is more preferable. If this equivalent ratio is less than 1, the crosslink density will be low, resulting in deterioration of scratch resistance and stain resistance.

The upper limit of the amount of the carbodiimide compound to be added is not particularly limited. / molar equivalent of carboxy group in polycarbonate-based urethane resin) is preferably 2 or less, more preferably 1.8 or less, and even more preferably 1.6 or less. If the addition amount of the carbodiimide compound exceeds 2 in terms of equivalent ratio, the content of the polycarbonate-based urethane resin is relatively decreased, and the amount of the carbodiimide compound that does not contribute to the curing reaction is increased. It may not be high enough.

As the resin contained in the topcoat layer 15 in the present embodiment, a polycarbonate-based urethane polymer (polycarbonate-based urethane resin) having an acid value of 10 mgKOH/g or more is crosslinked with a curing agent (for example, the carbodiimide curing agent described above). It is more preferable that the resin is a polycarbonate-based urethane polymer having a glass transition temperature of 80° C. or higher and an acid value of 10 mgKOH/g or higher crosslinked with a curing agent. Here, if the glass transition temperature is 80° C. or lower, the surface hardness of the top coat layer 15 may be lowered, and the scratch resistance may be lowered. Moreover, when the acid value is 10 mgKOH/g or less, the crosslink density after curing is low, and thus the scratch resistance may be lowered.

Although the upper limit of the glass transition temperature of the polycarbonate-based urethane polymer contained in the topcoat layer 15 in this embodiment is not particularly limited, it is preferably 200° C. or less, for example. If the glass transition temperature of the resin forming the topcoat layer 15 in the present embodiment exceeds 200° C., the surface hardness of the topcoat layer 15 becomes too high, and there is a possibility that the topcoat layer 15 becomes vulnerable to external impact.
Moreover, the upper limit of the acid value of the polycarbonate-based urethane polymer contained in the topcoat layer 15 in the present embodiment is not particularly limited, but is preferably 200 mgKOH/g or less, for example. If the acid value of the resin constituting the topcoat layer 15 in this embodiment exceeds 200 mgKOH/g, the crosslink density after curing becomes too high, and there is a possibility that the resin may become vulnerable to external impact.

Further, the polycarbonate-based urethane polymer contained in the top coat layer 15 is preferably applied in the form of an aqueous emulsion together with the curing agent. If the polycarbonate-based urethane polymer contained in the topcoat layer 15 is in the form of an aqueous emulsion and is coated together with the curing agent, a resin film having a high molecular weight can be obtained, and the surface hardness of the topcoat layer 15 is improved, and the surface hardness of the topcoat layer 15 is improved. Stainability is improved. Here, "aqueous emulsion" means an emulsion formed in water or a lower alcohol as a dispersion medium.

The top coat layer 15 is generally added with a filler as a gloss modifier in many cases. Silica (silica filler) made of an inorganic material is preferable in terms of properties. Silica exhibits better scratch resistance than other materials, which is considered to be due to silica having moderate hardness.
The particle size (average particle size D50) of silica is preferably 9 μm or less, more preferably 7 μm or less, and even more preferably 5 μm or less. If the particle size exceeds 9 μm, the particles are likely to be missing in the abrasion evaluation, which is not preferable.

Although the lower limit of the particle size of silica is not particularly limited, it is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 3 μm or more. If the particle size of the silica added to the topcoat layer 15 in this embodiment is less than 1 μm, the function as a gloss modifier may not be exhibited.

Silica preferably has a pore volume of 1 mL/g or more. Silica exhibits a tendency to be excellent in scratch resistance when the pore volume is large (specifically, 1 mL/g or more). . In addition, silica having a large pore volume has a large delustering function, and has a large effect of reducing the required addition amount of the gloss modifier. The content of the glossiness adjusting agent is preferably in the range of 1% by mass to 30% by mass, more preferably in the range of 2% by mass to 20% by mass, based on the total mass of the topcoat layer 15. is. That is, in the present embodiment, when silica (silica filler) having a pore volume of 1 mL/g or more is added as a glossiness adjusting agent, the silica content is , preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 20% by mass or less.
The silica may have a spherical shape.

In addition, silica preferably has an oil absorption of 100 mL/100 g to 200 mL/100 g, more preferably an oil absorption of 150 mL/100 g to 180 mL/100 g, and an oil absorption of 160 mL/100 g to 170 mL/100 g. More preferred. Silica has a large oil absorption (specifically, 100 mL/100 g to 200 mL/100 g) and tends to be excellent in scratch resistance, which is influenced by the increased affinity between the binder resin component and the silica surface. it is conceivable that. In addition, silica, which has a large oil absorption, has a large function of removing luster, and has a large effect of reducing the required addition amount of the gloss modifier. Therefore, in the present embodiment, when silica (silica filler) having an oil absorption of 100 mL/100 g to 200 mL/100 g is added as a glossiness adjusting agent, the silica content is equal to the weight of the entire topcoat layer 15. is preferably in the range of 1% by mass or more and 30% by mass or less, more preferably in the range of 2% by mass or more and 20% by mass or less. Further, the silica content is more preferably in the range of 10% by mass or more and 15% by mass or less with respect to the mass of the topcoat layer 15 as a whole.

In order to impart various functions to the top coat layer 15 constituting the decorative sheet 10 of the present embodiment, for example, a heat stabilizer, an antiblocking agent, a catalyst scavenger, a colorant, a light scattering agent, an antibacterial agent, and an antifungal agent. Various additives such as may be blended.

Moreover, an ultraviolet absorber or a light stabilizer can be added to the top coat layer 15 as a weather resistant agent, if necessary. As UV absorbers, for example, benzotriazole-based, benzoate-based, benzophenone-based, triazine-based, etc., and as light stabilizers, for example, hindered amine-based, etc., are generally added in any combination. That is, the topcoat layer 15 may contain, as weather resistance agents, an ultraviolet absorber having a triazine skeleton and a light stabilizer having a NOR-type skeleton. The content of the ultraviolet absorber having a triazine skeleton in the topcoat layer 15 is preferably in the range of 1% by mass or more and 15% by mass or less, and 3% by mass or more and 6% by mass or less with respect to the total mass of the topcoat layer 15. is more preferable. In addition, the content of the light stabilizer having a NOR-type skeleton in the topcoat layer 15 is preferably in the range of 1% by mass or more and 10% by mass or less, and 3% by mass or more and 6 It is more preferably in the range of mass % or less. If the content of the ultraviolet absorber having a triazine skeleton and the content of the light stabilizer having a NOR skeleton are within the above numerical ranges, the basic functions of the topcoat layer 15 such as scratch resistance and stain resistance can be achieved. Weather resistance can be further improved while maintaining the same.

Moreover, in the topcoat layer 15, the content of the ultraviolet absorber having a triazine skeleton is preferably greater than the content of the light stabilizer having a NOR-type skeleton, and is within the range of 1.5 times or more and 3 times or less. preferable. If the content of the ultraviolet absorber having a triazine skeleton is within the above numerical range, the weather resistance can be further improved while maintaining the basic functions of the topcoat layer 15 such as scratch resistance and stain resistance. can.

Further, particulate polyethylene wax can be added as a lubricant (wax) to the top coat layer 15 as necessary. Here, "polyethylene-based wax" means low-molecular-weight polyethylene having a molecular weight of tens of thousands or less. The term "wax" means "(1) solid or semi-solid at room temperature, having a melting point of 40° C. or higher, and (2) melting upon heating without decomposition and low viscosity."
As the polyethylene-based wax, for example, Sanyo Kasei's "Sun.Wax" series and Mitsui Chemicals, Inc.'s "Hi-Wax" series can be used. The content of the polyethylene-based wax in the topcoat layer 15 is, for example, preferably in the range of 1% by mass or more and 10% by mass or less, and in the range of 3% by mass or more and 6% by mass or less with respect to the total mass of the topcoat layer 15. Inside is more preferred. If the content of the polyethylene-based wax is within the above numerical range, the stain resistance can be further improved while maintaining the basic functions of the top coat layer 15 such as scratch resistance.

The lubricant that can be added to the topcoat layer 15 is not limited to the above-described particulate polyethylene wax, and may be, for example, particulate polyester wax.

Moreover, an antibacterial agent comprising a silver-supporting phosphate can be added to the topcoat layer 15 as necessary. The phosphate is not particularly limited as long as it is known, but preferably contains one or more metals selected from the group consisting of silver, titanium, cerium, zirconium, germanium, potassium, aluminum and gallium. . These metals allow the use of their isotopes. In the present embodiment, silver is particularly preferred because of its antibacterial ability. Moreover, a well-known method is used as a method of manufacturing a phosphate.
The silver-supported phosphate in the topcoat layer 15 is preferably used within a range of 1×10 ⁻⁴ mass % or more and 20 mass % or less, and is used within a range of 1 mass % or more and 15 mass % or less. is more preferably used within the range of 3% by mass or more and 10% by mass or less, and most preferably within the range of 5% by mass or more and 8% by mass or less. If the content of the silver-supporting phosphate is within the above numerical range, the antibacterial ability is reliably exhibited.
Here, in order to obtain antibacterial performance, it is preferable that the amount of the antibacterial agent added is relatively large. , sufficient surface strength cannot be obtained. Specifically, for example, when the thickness D of the topcoat layer 15 is in the range of 3 μm or more and 20 μm or less, the amount of the antibacterial agent added is 1×10 μm with respect to the mass of the entire topcoat layer 15 as described above. It is preferably in the range of ^-4 % by mass or more and 20% by mass or less. If the amount of the antibacterial agent added is less than 1×10 ⁻⁴ mass %, the antibacterial performance cannot be exhibited, and if it exceeds 20 mass %, the surface strength cannot be ensured.

The particle size (average particle size D50) of the silver-supporting phosphate is preferably 1 μm or more. If the particle size is less than 1 μm, the dispersibility is lowered and the function as an antibacterial agent may not be exhibited.
Although the upper limit of the particle size of the silver-supporting phosphate is not particularly limited, it is preferably 10 μm or less, for example. If the particle size of the silver-supported phosphate added to the topcoat layer 15 in the present embodiment exceeds 10 μm, the antibacterial agent is likely to be missing in the scratch resistance evaluation, which is not preferable.

The particle size (μm) of the antibacterial agent is 1 μm or more, preferably 0.1 to 1.0 times the thickness D (μm) of the topcoat layer 15, and 0.3 to 0.3 times. It is more preferably 4 times or less. If the average particle size of the antibacterial agent is less than 0.1 times the thickness D of the topcoat layer 15, the dispersibility of the antibacterial agent may decrease, and a sufficient antibacterial effect may not be obtained. If it exceeds, the surface hardness may decrease.

In addition, the above-mentioned antibacterial agent having a particle diameter (μm) of 1 μm or more and having a thickness D of 0.1 times or more and 1.0 times or less of the thickness D of the topcoat layer 15 is the “first antibacterial agent”. Assuming that the antibacterial agent has a particle diameter (μm) of 1 μm or more and is 1.4 to 1.6 times the thickness D of the topcoat layer 15 as the “second antibacterial agent” , the topcoat layer 15 may include a first antimicrobial agent and a second antimicrobial agent. That is, the topcoat layer 15 may contain two or more types of antibacterial agents having different average particle sizes. By including the second antibacterial agent, the second antibacterial agent protrudes from the surface of the topcoat layer 15, and the second antibacterial agent exhibits an antibacterial effect.

In addition, the ratio between the amount of the first antibacterial agent added and the amount of the second antibacterial agent added (amount of the first antibacterial agent added/amount of the second antibacterial agent added) is 1.5 or more and 10 or less. Any number is acceptable, more preferably 2 or more and 8 or less, and even more preferably 3 or more and 5 or less. Within the above numerical range, a high antibacterial effect can be obtained.
Also, the first antibacterial agent and the second antibacterial agent may be the same type of antibacterial agent (for example, the same type of silver-based antibacterial agent), or may be different types of antibacterial agents.

In addition to the silver-supported phosphate described above, the antibacterial agent that can be added to the topcoat layer 15 includes, for example, inorganic compounds such as zeolite, apatite, and zirconia, and silver ions, copper ions, and zinc ions. Inorganic antibacterial agents such as antibacterial zeolite, antibacterial apatite, and antibacterial zirconia formed by incorporating metal ions can be used. Antibacterial agents include organic antibacterial agents such as zinc pyridione, 2-(4-thiazolyl)-benzimidazole, 10,10-oxybisphenoxanodine, organic sulphurous halogen, and pyridine-2-thiol-oxide. A silver-based antibacterial agent (an antibacterial agent containing a silver-based material) is superior in terms of antibacterial effect.

Further, the antibacterial agent may have a structure in which a silver-based material is supported on an inorganic material. As the "inorganic material", for example, "glass" can be used.
By supporting the silver component (silver-based material) on the inorganic material, it is possible to prevent the silver component from falling off over time and from transferring to adjacent layers. The antimicrobial agent may also include finely divided silver.
Specifically, the antibacterial agent that can be used in the present embodiment includes a diiodomethyl complex (trade name; PBM-H7, manufactured by MIC) and a calcium hydroxide calcined product (trade name; Scallow, manufactured by Bacteriological Research Institute). ), or “Biocide TB-B100 (trade name)” (manufactured by Taisho Technos Co., Ltd.).

The antibacterial agent described above may be added not only to the topcoat layer 15 but also to the transparent resin layer 14 . As a result, even when the transparent resin layer 14 is exposed due to abrasion or the like, the antibacterial performance can be maintained. The amount of the antibacterial agent added to the transparent resin layer 14 is preferably 1% by mass or more and 30% by mass or less with respect to the total mass of the transparent resin layer 14 . The average particle size of the antibacterial agent is preferably 2 μm or more and 20 μm or less, more preferably 5 μm or more and 12 μm or less. When an antibacterial agent is added to the transparent resin layer 14, it is preferable not to add a chlorine-containing component to the transparent resin layer 14.

Further, in the above-described embodiment, the case where an antibacterial agent is added to the topcoat layer 15 has been described, but the antibacterial agent may be an antiviral agent having antiviral performance. That is, in the present embodiment, instead of the antibacterial agent, an antiviral agent may be added to the topcoat layer 15, or both the antibacterial agent and the antiviral agent may be added to the topcoat layer 15.
The addition amount, average particle size, and the like of the antiviral agent added to the topcoat layer 15 may be the same as those of the antibacterial agent described above. In addition, two or more antiviral agents having different average particle sizes may be added to the topcoat layer 15 as in the case of the antibacterial agent.

The resin forming the topcoat layer 15 has a crosslinked structure.
By forming the topcoat layer 15 to have a crosslinked structure, it becomes possible to block transfer of the antibacterial agent containing the silver component. The crosslinked structure can be crosslinked with high energy such as ultraviolet rays, electron beams, or heat to increase the degree of crosslinking and further suppress transfer of the antibacterial agent containing the silver component.

A method for forming the topcoat layer 15 is not particularly limited. The top coat layer 15 is formed by coating the above-mentioned material in a coating liquid by a usual method such as gravure coat, micro gravure coat, comma coat, knife coat, die coat, etc., and then heat curing, ultraviolet curing, etc. suitable for the material. It may be formed by curing by a method described above.
Further, the topcoat layer 15 may be provided after the pattern layer 12 provided on the base material layer 11 is joined to the transparent resin layer 14 via the anchor layer 13 .

The thickness of each layer constituting the decorative sheet 10 of this embodiment will be described below. Considering printing workability, cost, etc., the thickness of the base material layer 11 is preferably in the range of 20 μm to 150 μm, more preferably in the range of 50 μm to 100 μm.
Similarly, considering printing workability, cost, etc., the thickness of the pattern layer 12 is preferably in the range of 0.5 μm to 10 μm, more preferably in the range of 1 μm to 5 μm.
Similarly, considering printing workability, cost, etc., the thickness of the anchor layer 13 is preferably in the range of 1 μm to 20 μm, more preferably in the range of 1 μm to 3 μm.
Similarly, considering printing workability, cost, etc., the thickness of the transparent resin layer 14 is preferably in the range of 20 μm to 200 μm, more preferably in the range of 70 μm to 100 μm.
Similarly, considering printing workability, cost, etc., the thickness of the top coat layer 15 is preferably in the range of 3 μm to 20 μm, more preferably in the range of 3 μm to 15 μm.
Also, the total thickness of the decorative sheet 10 is preferably within the range of 45 μm or more and 250 μm or less. If the total thickness of the decorative sheet 10 is less than 45 μm, the overall strength of the decorative sheet 10 is insufficient, and for example, when the decorative sheet 10 is manufactured in-line, the decorative sheet 10 may be damaged during manufacture. If the total thickness of the decorative sheet 10 exceeds 250 μm, the overall flexibility of the decorative sheet 10 is reduced, and the decorative sheet 10 may be cracked or whitened.

[Method for manufacturing decorative sheet]
A method for manufacturing the decorative sheet 10 according to this embodiment will be briefly described below.
First, the pattern layer 12 is formed on the base material layer 11 containing polyolefin.
Next, an anchor layer 13 is formed on the pattern layer 12 .
Next, a transparent resin layer 14 containing polypropylene as a main component is formed on the anchor layer 13 by extrusion molding to a thickness of 70 μm or more and 100 μm or less.
Next, on the transparent resin layer 14, a topcoat layer 15 containing a polycarbonate-based urethane resin, a carbodiimide curing agent, an inorganic filler, a wax, an ultraviolet absorber, a light stabilizer, and an antibacterial agent is formed to a thickness of 3 μm or more. It is formed with a film thickness of 15 μm or less.

Moreover, in the step of forming the transparent resin layer 14, the surface of the transparent resin layer 14 may be treated so that the wettability index of the surface is 60 dyne or more. The wetting index on the surface of the transparent resin layer 14 can be confirmed using a so-called "wetting reagent".

In at least one of the step of forming the anchor layer 13 and the step of forming the topcoat layer 15, each layer may be formed using any one of gravure printing, flexographic printing, and inkjet printing.

As described above, the method for manufacturing the decorative sheet 10 of the present embodiment includes the base layer 11 containing polyolefin, the pattern layer 12, the anchor layer 13, the transparent resin layer 14 containing polypropylene as a main component, and the top coat. It includes at least a step of forming the layer 15 in this order. In the step of forming the topcoat layer 15 , the topcoat layer 15 is formed by coating the transparent resin layer 14 with a topcoat layer coating material, which is an aqueous coating liquid. Here, the coating material for the topcoat layer contains a polycarbonate-based urethane resin, a carbodiimide curing agent, an inorganic filler, a wax, an ultraviolet absorber, a light stabilizer, and an antibacterial agent. The polycarbonate-based urethane resin preferably has an acid value of 10 mgKOH/g or more and is contained in the topcoat layer coating material in the form of an aqueous emulsion.

EXAMPLES Examples based on the present invention will be described below.

<Example 1>
~ Preparation of coating material for top coat layer ~
A coating material for a topcoat layer was prepared according to the following recipe.
・ Resin (polycarbonate urethane 1): Polycarbonate urethane polymer W-6010 (manufactured by Mitsui Chemicals), 100 parts by mass ・ Curing agent (carbodiimide 1): Carbodiimide curing agent SV-02 (manufactured by Nisshinbo Chemical), 10 parts by mass · Filler (silica); Mizukasil P803 (manufactured by Mizusawa Chemical), particle size 5 μm, 2.5 parts by mass · Wax (polyethylene system); AQUAMAT263 (manufactured by BYK Chemie), 5 parts by mass · Ultraviolet absorber (triazine system); Tinuvin400DW ( BASF), 1 part by mass Light stabilizer (NOR type); Tinuvin123DW (BASF), 1 part by mass Antibacterial agent (silver-carrying type); Apacider AW (Zangi), particle size 2 μm, 0.3 parts by mass

～Creating a makeup sheet～
As the base material layer 11, a 55 μm-thick polyethylene sheet with concealability is used, and a 3 μm-thick picture layer 12 is formed on one side by a gravure printing method using a two-liquid urethane ink (V180, manufactured by Toyo Ink). , and a primer coat composed of the same resin component as that of the pattern layer 12 was provided on the other surface of the base material layer 11 .
On the surface of this pattern layer 12, an anchor layer 13 with a thickness of 2 μm is provided by a gravure printing method using an adhesive for dry lamination (Takelac A540, manufactured by Mitsui Chemicals, Inc.). A transparent resin layer 14 having a thickness of 70 μm was formed by extrusion lamination of a polypropylene resin containing 0.5% by mass of a hindered amine light stabilizer.
Furthermore, the decorative sheet 10 of Example 1 was produced by providing the topcoat layer 15 with a thickness of 7 μm on the transparent resin layer 14 using the above-described topcoat layer coating material by gravure coating.

~Evaluation of Adhesion~
Adhesion evaluation of the decorative sheet 10 described above was performed under the following conditions, and the state of the sample after the test was visually evaluated.
<Test conditions>
- The surface of the top coat layer was cross-cut with a cutter, and a sellotape (registered trademark) peeling test was performed.
<Evaluation criteria>
◯: No peeling △: Partial peeling ×: Easy peeling In this evaluation, “◯” was regarded as a pass.

-Evaluation of scratch resistance-
The scratch resistance evaluation of the decorative sheet 10 described above was performed under the following conditions, and the state of the sample after the test was visually evaluated.
<Test conditions>
・Hoffman scratch test: BYK Hoffman scratch hardness tester ・Test conditions: 100 to 1000 g load, 100 g increments
<Evaluation criteria>
◯: No scratch with a load of 500 g or more △: No scratch with a load of 100 g or more and less than 500 g ×: Scratches occurred even with a scratch of less than 100 g load In this evaluation, “◯” was regarded as a pass.

-Evaluation of contamination resistance-
The stain resistance evaluation of the decorative sheet 10 described above was performed under the following conditions, and the state of the sample after the test was visually evaluated.
<Test conditions>
- A 1% sodium hydroxide aqueous solution was dropped on the surface, and the surface condition was visually observed after being left for 24 hours.
<Evaluation criteria>
○: No traces △: Slight traces ×: Clear traces due to dissolution In this evaluation, "◯" was regarded as a pass.

-Evaluation of antibacterial properties-
Antibacterial evaluation of the decorative sheet 10 described above was carried out under the following conditions to evaluate the antibacterial performance.
<Test conditions>
・An antibacterial test was performed based on JIS Z 2801:2010 (film adhesion method). Escherichia coli and Staphylococcus aureus were added dropwise to each of the decorative sheets of Examples and Comparative Examples as contaminants, and the sheets were stored in a dark place at 25° C. for 24 hours. After that, the number of viable bacteria was counted, and the antibacterial activity value was calculated. An antibacterial activity value of 2.0 or more is acceptable (antibacterial).
<Evaluation criteria>
◯: 2.0 or more ×: Less than 2.0 In this evaluation, “◯” was regarded as a pass.

～Evaluation of weather resistance～
Weather resistance evaluation of the decorative sheet 10 described above was performed under the following conditions, and the state of the sample after the test was visually evaluated.
<Test conditions>
・Super xenon tester; Atlas Weatherometer Ci4000 manufactured by Toyo Seiki Co., Ltd.
・Test conditions: 180 W light irradiation, 12 min rain/120 min cycle, 500 hr
<Evaluation criteria>
◯: No change before and after the test △: A part of the sample after the test was whitened. However, the whitening was at a level causing no problem in use.
x: A whitened portion or a partially peeled portion was observed in the sample after the test. The whitening and peeling were at the level of problems in use.
In this evaluation, "0" was set as a pass.

<Example 2>
Example 2 was prepared in the same manner as in Example 1 except that polycarbonate-based urethane polymer WS-5100 (manufactured by Mitsui Chemicals) was used as the resin (polycarbonate-based urethane 2) in the formulation of the coating material for the topcoat layer of Example 1. A cosmetic sheet was prepared and evaluated.

<Example 3>
In the formulation of the coating material for the topcoat layer of Example 1, except that the resin (polycarbonate urethane 3) was polycarbonate-based urethane polymer D-6300 (manufactured by Dainichiseika Co., Ltd.), the same method as in Example 1 was used. 3 was prepared and evaluated.

<Example 4>
In the formulation of the coating material for the topcoat layer of Example 1, except that the curing agent (carbodiimide 2) was a carbodiimide-based curing agent V-02 (manufactured by Nisshinbo Chemical), Example 4 was prepared in the same manner as in Example 1. A cosmetic sheet was prepared and evaluated.

<Example 5>
A decorative sheet of Example 5 was prepared in the same manner as in Example 1, except that the filler (silica) in the formulation of the coating material for the topcoat layer in Example 1 was Mizukasil P501 (manufactured by Mizusawa Kagaku) and the particle size was 10 μm. created and evaluated.

<Example 6>
In the formulation of the coating material for the topcoat layer of Example 1, except that the antibacterial agent (alkaline type) was Apacider AW (manufactured by Zangi) and the particle size was 0.2 μm, the method of Example 6 was repeated in the same manner as in Example 1. A cosmetic sheet was prepared and evaluated.

<Comparative Example 1>
A comparative example was prepared in the same manner as in Example 1, except that the resin (polyether-based urethane) in the formulation of the coating material for the topcoat layer of Example 1 was changed to polyether-based urethane polymer W-6061 (manufactured by Mitsui Chemicals). A decorative sheet No. 1 was prepared and evaluated.

<Comparative Example 2>
Comparative Example 2 was prepared in the same manner as in Example 1 except that the curing agent (epoxy) in the formulation of the coating material for the topcoat layer of Example 1 was changed to epoxy-based curing agent EX-810 (manufactured by Nagase Chemtech). A cosmetic sheet was prepared and evaluated.

As shown in Table 1, according to this example, a decorative sheet having excellent physical properties such as weather resistance, scratch resistance, and stain resistance can be obtained.

10 decorative sheet 11 base material layer 12 pattern layer 13 anchor layer 14 transparent resin layer 15 top coat layer

Claims (10)

a polyolefin base material;
a pattern layer formed on the polyolefin base material;
an anchor coat layer formed on the pattern layer;
a transparent resin layer formed on the anchor coat layer and containing polypropylene as a main component;
and a top coat layer formed on the transparent resin layer,
The decorative sheet, wherein the top coat layer contains a polycarbonate-based urethane resin, a carbodiimide curing agent, an inorganic filler, a wax, an ultraviolet absorber, a light stabilizer, and an antibacterial agent. 2. The decorative sheet according to claim 1, wherein the polycarbonate-based urethane resin contained in the topcoat layer has an acid value of 10 mgKOH/g or more. The addition amount of the carbodiimide curing agent contained in the topcoat layer is the molar equivalent ratio (mmol/g) of the carbodiimide to the molar equivalent (mmol/g) of the carboxy group in the polycarbonate-based urethane resin (mol 3. The decorative sheet according to claim 1, wherein the equivalent weight/molar equivalent weight of carboxy groups in the polycarbonate-based urethane resin) is 1 or more. 4. The decorative sheet according to any one of claims 1 to 3, wherein the inorganic filler contained in the topcoat layer is a silica filler having a particle size of 9 µm or less. 5. The decorative sheet according to any one of claims 1 to 4, wherein the antibacterial agent contained in the topcoat layer is fine particles having a particle size of 1 µm or more and made of silver-supporting phosphate. 6. The decorative sheet according to any one of claims 1 to 5, wherein the wax contained in the topcoat layer is polyethylene particles. 7. The decorative sheet according to any one of claims 1 to 6, wherein the ultraviolet absorber contained in the topcoat layer has a triazine skeleton. 8. The decorative sheet according to any one of claims 1 to 7, wherein the light stabilizer contained in the topcoat layer has a NOR-type skeleton. A method for manufacturing a decorative sheet for manufacturing the decorative sheet according to any one of claims 1 to 8,
A method for producing a decorative sheet, wherein the topcoat layer is formed from an aqueous coating liquid. 10. The method for producing a decorative sheet according to claim 9, wherein the polycarbonate-based urethane resin having an acid value of 10 mgKOH/g or more is contained in the aqueous coating liquid in the form of an aqueous emulsion.

Images