JP2023180071A - Decorative sheet and method for manufacturing the same - Google Patents

Abstract

To provide a decorative sheet which can improve scratch resistance, stain resistance and weather resistance, and a method for manufacturing the same.SOLUTION: In a decorative sheet 10 having a base material 11, a pattern layer 12 provided on the base material 11, an adhesive layer 13 provided on the pattern layer 12, a transparent resin layer 14 provided on the adhesive layer 13 and a surface protective layer 15 provided on the transparent resin layer 14, the surface protective layer 15 contains a reaction product of a polycarbonate-based urethane resin and a carbodiimide-based curing agent, and a ratio (intensity A/intensity B) of peak intensity A of a wave number of maximum intensity existing between 1,800 cm-1 and 1,850 cm-1 to peak intensity B of a wave number of maximum intensity existing between 1,700 cm-1 and 1,800 cm-1, which are measured from the surface of the surface protective layer 15 by an infrared spectroscopic analysis method, is 0.01 or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to a decorative sheet used for the interior and exterior of buildings, fittings, furniture, etc., and a method for manufacturing the same.

With the recent diversification of use environments for decorative sheets, there has been a strong demand for higher functionality. Generally, it is difficult to simultaneously improve all physical properties such as weather resistance, scratch resistance, and stain resistance. Therefore, a surface protective layer is often provided on the outermost layer of the decorative sheet for the purpose of imparting functionality. When imparting weather resistance to this surface protective layer, it is common to add a weathering agent such as an ultraviolet absorber or a light stabilizer. As a prior art, for example, there is a decorative sheet described in Patent Document 1.

JP 2019-30998 Publication

Since decorative sheets are increasingly being used for the exterior of buildings, there is a strong demand for improved weather resistance. In order to improve the weather resistance of decorative sheets, it is common to add weathering agents such as ultraviolet absorbers and light stabilizers to the surface protective layer. However, if the amount of weathering agent added to the surface protective layer is increased in order to improve the weather resistance of the decorative sheet, the scratch resistance and stain resistance of the surface protective layer may be reduced. In other words, in the physical properties of the decorative sheet, there is a so-called trade-off relationship between improvement in weather resistance and improvement in scratch resistance and stain resistance.

Therefore, an object of the present invention is to provide a decorative sheet that can improve scratch resistance, stain resistance, and weather resistance, and a method for manufacturing the same.

In order to solve the above-mentioned problems, the decorative sheet according to the present invention includes a base material, a pattern layer provided on the base material, an adhesive layer provided on the pattern layer, and a decorative sheet provided on the adhesive layer. A decorative sheet comprising a transparent resin layer and a surface protection layer provided on the transparent resin layer,
(1) The surface protective layer contains a reaction product of a polycarbonate-based urethane resin and a carbodiimide-based curing agent,
(2) 1800 cm ^-1 and 1850 cm ^-1 with respect to the peak intensity B of the wave number of the maximum intensity existing between 1700 cm ^-1 and 1800 cm ^-1 measured from the surface of the surface protective layer by infrared spectroscopy It is characterized in that the ratio of the peak intensity A of the wave number of the maximum intensity existing between the two (intensity A/intensity B) is 0.01 or more.

Further, in the decorative sheet according to the present invention, the surface protective layer preferably has a Martens hardness of 30 N/mm ² or more and 150 N/mm ² or less in the cross-sectional direction.

Moreover, in the decorative sheet according to the present invention, the surface protective layer preferably has a thickness of 2 μm or more and 15 μm or less.

Further, in the decorative sheet according to the present invention, in the decorative sheet described above, it is preferable that the surface protective layer contains a filler.

Further, in the decorative sheet according to the present invention, in the decorative sheet described above, it is preferable that the filler is silica particles.

Further, in the decorative sheet according to the present invention, in the decorative sheet described above, it is preferable that the surface protective layer contains an ultraviolet absorber.

Further, in the decorative sheet according to the present invention, in the decorative sheet described above, it is preferable that the surface protective layer contains a light stabilizer.

Further, in the decorative sheet according to the present invention, in the decorative sheet described above, the surface protective layer is preferably formed from an aqueous composition.

Moreover, in the decorative sheet according to the present invention, in the decorative sheet described above, it is preferable that the transparent resin layer is made of an olefin resin.

Further, in the decorative sheet according to the present invention, in the decorative sheet described above, it is preferable that the adhesive layer contains a polyurethane resin.

On the other hand, in order to solve the above-mentioned problems, the method for manufacturing a decorative sheet according to the present invention includes a pattern layer forming step of providing a pattern layer on the base material, and an adhesive layer forming step of providing an adhesive layer on the pattern layer. and a method for producing a decorative sheet, comprising: a transparent resin layer forming step of providing a transparent resin layer on the adhesive layer; and a surface protection layer forming step of providing a surface protective layer on the transparent resin layer. The process is measured from the surface by infrared spectroscopy, with the peak intensity B existing between 1800 cm ⁻¹ and 1850 cm ⁻¹ for a wave number of maximum intensity existing between 1700 cm ⁻¹ and 1800 cm ⁻¹ A product obtained by reacting a polycarbonate urethane resin and a carbodiimide curing agent such that the ratio of peak intensity A of the wave number of the maximum intensity (intensity A/intensity B) becomes 0.01 or more. The present invention is characterized by comprising a step of providing the surface protective layer containing the product as a main component on the transparent resin layer.

According to the present invention, the scratch resistance, stain resistance, and weather resistance of the decorative sheet can be improved.

1 is a sectional view showing a schematic structure of a main embodiment of a decorative sheet according to the present invention.

Embodiments of a decorative sheet and a method for manufacturing the same according to the present invention will be described below based on the drawings. Note that the descriptions in the drawings below are schematic, and the relationship between thickness and planar dimension, the ratio of the thickness of each layer, etc. are different from the actual ones. Therefore, the specific thickness and dimensions should be determined with reference to the following explanation. In addition, the embodiments shown below exemplify devices and methods for embodying the technical idea of the present invention. etc. are not specified as those listed below. The technical idea of the present invention can be modified in various ways within the technical scope defined by the claims.

[Main embodiment]
A main embodiment of a decorative sheet and a method for manufacturing the same according to the present invention will be described based on FIG. 1.

<Overall composition of decorative sheet>
As shown in FIG. 1, the decorative sheet 10 includes a base material 11, a pattern layer 12 provided on the base material 11, an adhesive layer 13 provided on the pattern layer 12, and a transparent resin provided on the adhesive layer 13. layer 14 and a surface protection layer 15 provided on the transparent resin layer 14. That is, the decorative sheet 10 includes a base layer 11, a pattern layer 12, an adhesive layer 13, a transparent resin layer 14, and a surface protection layer 15, which are laminated in this order. In addition, the code|symbol 19 is a primer layer.

The thickness of the decorative sheet 10 is preferably within the range of 45 μm or more and 250 μm or less. If it is less than 45 μm, the strength of the decorative sheet 10 as a whole will decrease, and there is a risk that it will be damaged during manufacturing. If it exceeds 250 μm, the flexibility of the decorative sheet 10 as a whole decreases, and there is a risk of cracking, whitening, etc.

<Base material layer 11>
The base material layer 11 can be arbitrarily selected from resin, resin foam, rubber, paper, nonwoven fabric, synthetic paper, metal foil, etc., and resin is preferable. The resin is preferably a thermoplastic resin, and examples include polyolefin resins such as polyethylene, polypropylene, and polybutylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, polyurethane, ABS resin, AS resin, and acrylic resin. It is also possible to apply these copolymers, kneading of multiple resins, and laminates of multiple layers. In particular, polyolefin resins are suitable, and among them, polyethylene is most suitable.

When the base material layer 11 contains a polyolefin resin, that is, it also contains a resin other than polyolefin, or is made of only polyolefin, the generation of harmful gases etc. at the time of disposal can be reduced. When the base material layer 11 contains polyethylene or consists only of polyethylene, the generation of harmful gases etc. at the time of disposal can be further reduced.

The base material 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 improve adhesion with adjacent layers. It is.

Considering manufacturing workability, cost, etc., the thickness of the base layer 11 is preferably within the range of 20 μm or more and 150 μm or less, and more preferably within the range of 50 μm or more and 100 μm or less.

<Picture layer 12>
The pattern layer 12 is a pattern printed layer that is printed on the base material layer 11 using ink.

The ink forming the pattern layer 12 contains a binder. As the binder, for example, nitrified cotton, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, polyester, and the like can be used alone or appropriately selected from modified products thereof. Any of aqueous, solvent-based, and emulsion types can be used as the binder, and either a one-component type or a two-component type using a hardening agent can be used.

The pattern layer 12 can also be formed, for example, by using urethane-based ink and curing it with an isocyanate-based curing agent. The curing agent used for curing urethane ink is not particularly limited, and examples thereof include hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate and its hydrogenated product, or diphenylmethane diisocyanate and its hydrogenated product. The curing agent can be appropriately selected from commercially available curing agents including the following. Furthermore, it is also possible to use a photocurable ink or the like and to cure it by irradiating it with ultraviolet rays, electron beams, or the like.

In addition to the binder described above, the pattern layer 12 can also contain colorants such as pigments and dyes, extender pigments, solvents, various additives, etc. that are contained in ordinary inks. Examples of highly versatile pigments include pearl pigments such as condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, and mica.

It is preferable that the above-described ink contains a light stabilizer because deterioration of the decorative sheet 10 itself caused by photodeterioration of the ink can be suppressed and the life of the decorative sheet 10 can be extended. When the content of the light stabilizer is within the range of 1% by mass or more and 5% by mass or less based on the mass of the entire ink, it is possible to effectively suppress deterioration of the decorative sheet 10 itself caused by photodegradation of the ink. This is preferable because it can be done.

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

The thickness of the pattern layer 12 is preferably within the range of 0.5 μm or more and 10 μm or less, and more preferably within the range of 1 μm or more and 5 μm or less, considering manufacturing workability, cost, etc.

<Adhesive layer 13>
The adhesive layer 13 is a layer provided to improve the adhesiveness between the pattern layer 12 and the transparent resin layer 14.

The material constituting the adhesive layer 13 is not particularly limited, and may be selected from resin materials such as urethane, acrylic, acrylic silicone, fluorine, epoxy, and polyester. A material that has excellent adhesion to 14 can be appropriately selected and used after being made into an ink.

The method for forming the adhesive layer 13 is not particularly limited, and it can be formed by, for example, applying a normal coating method such as gravure coating, microgravure coating, comma coating, knife coating, or die coating.

Considering manufacturing workability, cost, etc., the thickness of the adhesive layer 13 is preferably within the range of 1 μm or more and 20 μm or less, and more preferably within the range of 1 μm or more and 3 μm or less.

<Transparent resin layer 14>
The transparent resin layer 14 is a layer provided to improve the overall strength (mechanical strength) of the decorative sheet 10 and to enhance the design by providing unevenness.

The transparent resin layer 14 is a layer containing polypropylene as a main component. Here, "main component" means a state in which the mass of polypropylene occupies 50% by mass or more of the mass of the entire transparent resin layer 14. The transparent resin layer 14 can contain resin components other than polypropylene. As a material other than polypropylene that can be contained in the transparent resin layer 14, an olefin resin is preferably mentioned.

In addition to polypropylene, olefin resins that can be contained in the transparent resin layer 14 include not only polyethylene and polybutene, but also α-olefins (for example, 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, Homopolymerization or copolymerization of two or more of 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc.) ethylene/vinyl acetate copolymer, ethylene/vinyl alcohol copolymer, ethylene/methyl methacrylate copolymer, ethylene/ethyl methacrylate copolymer, ethylene/butyl methacrylate copolymer, ethylene/methyl acrylate copolymer Examples include copolymers of ethylene or α-olefin and other monomers, such as ethylene/ethyl acrylate copolymers, ethylene/butyl acrylate copolymers, and the like.

In particular, it is preferable to use highly crystalline polypropylene as the resin material constituting the transparent resin layer 14 because the surface strength of the decorative sheet 10 can be improved. That is, the transparent resin layer 14 is preferably a layer containing highly crystalline polypropylene as a main component.

The transparent resin layer 14 can also contain, as a weathering agent, an ultraviolet absorber having a triazine skeleton and a light stabilizer having a NOR type skeleton. Examples of weathering agents include benzophenone-based UV absorbers, and hindered amine-based weathering agents as light stabilizers. The benzophenone-based ultraviolet absorber is preferably added in an amount of 0.1% by mass or more and 5% by mass or less based on the mass of the entire transparent resin layer 14 . The amount of the hindered amine light stabilizer added is preferably within the range of 0.1% by mass to 5% by mass, based on the total mass of the transparent resin layer 14 .

The transparent resin layer 14 can also contain various additives such as a heat stabilizer, a light stabilizer, an antiblocking agent, a catalyst scavenger, a coloring agent, a light scattering agent, and a gloss modifier, as necessary. Examples of the heat stabilizer include phenol type, sulfur type, phosphorus type, hydrazine type and the like. Examples of the light stabilizer include hindered amine type stabilizers. These additives are appropriately added and contained in common combinations.

The method of 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 these, extrusion molding is preferred as a method for forming the transparent resin layer 14. If extrusion molding is used, the transparent resin layer 14 can be formed uniformly.

The transparent resin layer 14 can also be given a design by providing unevenness on its surface. Examples of methods for providing unevenness on the surface include a method in which heat embossing is performed after extrusion molding the transparent resin layer 14, a method in which embossing is performed at the same time as extrusion molding using a cooling roll provided with projections and recesses during extrusion molding, etc. can be mentioned.

The thickness of the transparent resin layer 14 is preferably within the range of 20 μm or more and 200 μm or less, and more preferably within the range of 70 μm or more and 100 μm or less, considering manufacturing workability, cost, etc.

<Surface protective layer 15>
The surface protection layer 15 is a layer provided to impart various functions to the decorative sheet 10, such as scratch resistance, stain resistance, weather resistance, and design.

The surface protective layer 15 mainly contains a reaction product of a polycarbonate urethane resin and a carbodiimide curing agent. Here, the term "main component" refers to a state where the reaction product of the polycarbonate urethane resin and the carbodiimide curing agent accounts for 50% by mass or more of the surface protective layer 15. The surface protective layer 15 can be formed by crosslinking and curing a polycarbonate urethane resin and a carbodiimide curing agent using heat.

The surface protective layer 15 can also contain, for example, other thermosetting resins in addition to the reaction product of the polycarbonate-based urethane resin and the carbodiimide-based curing agent, which are the main components. Examples of other thermosetting resins include those formed by crosslinking and curing a resin containing a carboxy group and a carbodiimide curing agent using heat. The polymer containing a carboxyl group is not particularly limited, and examples thereof include various acrylic resins, polyester resins, polyether resins, and the like other than polycarbonate-based urethane resins. By further containing such a resin containing a carboxyl group, it is possible to further impart mechanical properties due to elongation of the molecular structure, for example.

The polycarbonate urethane resin preferably has a glass transition temperature of 80° C. or higher and an acid value of 10 mgKOH/g or higher. If the glass transition temperature is less than 80° C., the surface hardness of the surface protective layer 15 tends to be low, which may lead to a decrease in scratch resistance. If the acid value is less than 10 mgKOH/g, the crosslinking density after curing tends to be low, which may lead to a decrease in scratch resistance and stain resistance.

The polycarbonate-based urethane resin is preferably an aqueous emulsion type that is emulsified with water to form an aqueous composition. When the polycarbonate-based urethane resin is an aqueous emulsion-type aqueous composition, a film with a high molecular weight can be easily formed, and the surface hardness of the surface protective layer 15 can be improved, as well as stain resistance. can be achieved.

The carbodiimide curing agent is not particularly limited, but includes, for example, N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, N-[3- (dimethylamino)propyl]-N'-ethylcarbodiimide, N-[3-(dimethylamino)propyl]-N'-ethylcarbodiimide methiodide, N-tert-butyl-N'-ethylcarbodiimide, N-cyclohexyl- Examples include N'-(2-morpholinoethyl)carbodiimide meso-p-toluenesulfonate, N,N'-di-tert-butylcarbodiimide, and N,N'-di-p-tolylcarbodiimide. These carbodiimide curing agents can be used alone or in combination of two or more.

If the carbodiimide curing agent is added in an appropriate amount, it can improve scratch resistance, stain resistance, and weather resistance. However, if the amount of the curing agent added is too large, there is a possibility that the surface protective layer 15 becomes easily brittle. Therefore, the amount of the curing agent is preferably 40 parts by mass or less, and more preferably 1 part by mass or more and 20 parts by mass or less, based on 100 parts by mass of the resin component in the surface protection layer 15.

The surface protective layer 15 generally often contains a filler as a gloss adjuster (light scattering agent). Examples of the filler include organic fillers such as acrylic beads and silicone beads, and inorganic fillers such as alumina and silica. In particular, silica particles as an inorganic filler are preferred because they can improve scratch resistance. Silica exhibits good scratch resistance compared to other materials, and this is thought to be due to silica having appropriate hardness. The silica particles preferably have a particle diameter of 9 μm or less. If the particle diameter exceeds 9 μm, it is not preferable because particles may easily become missing.

Silica preferably has a pore volume of 1 mL/g or more. Silica tends to have excellent scratch resistance when its pore volume is large (specifically, 1 mL/g or more). This is thought to be largely due to the impregnation of the binder resin component into the pores of the silica. Silica, which has a large pore volume, has a great ability to remove gloss, and has a great effect in reducing the amount of gloss modifier needed to be added.

The gloss modifier is preferably contained in a range of 1% by mass or more and 30% by mass or less, and preferably contained in a range of 2% by mass or more and 20% by mass or less, based on the mass of the entire surface protective layer 15. It is even better if there is. In other words, when adding silica particles with a pore volume of 1 mL/g or more as a gloss modifier, the amount should be within the range of 1% by mass or more and 30% by mass or less based on the entire mass of the surface protective layer 15. It is preferable to add it, and it is more preferable to add it in an amount of 2% by mass or more and 20% by mass or less.

The amount of silica to be supplied is preferably 100 mL/100 g or more and 200 mL/100 g or less. Silica tends to have excellent scratch resistance when the amount of oil supplied is large (specifically, 100 mL/100 g or more and 200 mL/100 g or less). This is thought to be due to the increased affinity between the binder resin component and the silica surface. Silica, which requires a large amount of oil, has a great ability to remove gloss and has a great effect in reducing the amount of gloss modifier needed to be added.

Therefore, when adding silica particles as a gloss modifier with an oil supply amount of 100 mL/100 g or more and 200 mL/100 g or less, it should be in the range of 1 mass % or more and 30 mass % or less based on the entire mass of the surface protective layer 15. It is preferable to add it so that it becomes, and it is more preferable to add it so that it is in the range of 2% by mass or more and 20% by mass or less.

The surface protective layer 15 can also contain weathering agents such as ultraviolet absorbers and light stabilizers as necessary. Examples of the ultraviolet absorber include benzotriazole-based, benzoate-based, benzophenone-based, triazine-based, and the like. Examples of the light stabilizer include hindered amine type stabilizers. The weathering agent generally contains any combination of ultraviolet absorbers, light stabilizers, and the like. For example, a UV absorber having a triazine skeleton and a light stabilizer having a NOR type skeleton are contained in the surface protective layer 15 as weathering agents.

The surface protective layer 15 preferably contains an ultraviolet absorber having a triazine skeleton in a range of 1% by mass or more and 15% by mass or less, and 3% by mass or more and 6% by mass, based on the total mass of the surface protective layer 15. It is more preferable that the content is within the range of % by mass or less. The surface protective layer 15 preferably contains a light stabilizer having a NOR type skeleton in a range of 1% by mass or more and 10% by mass or less, and 3% by mass or more, based on the total mass of the surface protective layer 15. It is more preferable that the content is within the range of 6% by mass or less. When the ultraviolet absorber having a triazine skeleton or the light stabilizer having a NOR type skeleton is contained within the above numerical range, the basic functions of the surface protective layer 15 such as scratch resistance and stain resistance can be maintained. , weather resistance can be further improved.

The surface protective layer 15 preferably contains an ultraviolet absorber having a triazine skeleton in an amount larger than that of a light stabilizer having a NOR type skeleton, particularly in a range of 1.5 times or more and 3 times or less. It is more preferable if there is. When the ultraviolet absorber having a triazine skeleton is contained within the above numerical range, weather resistance can be further improved while maintaining the basic functions of the surface protective layer 15 such as scratch resistance and stain resistance. can.

The surface protective layer 15 can also contain a lubricant such as polyethylene wax as necessary. Here, "polyethylene wax" means low molecular weight polyethylene with a molecular weight of tens of thousands or less. Furthermore, the term "wax" refers to "(1) a solid or semi-solid substance at room temperature, with a melting point of 40°C or higher, and (2) a substance that melts without decomposition when heated and has a low viscosity."

As the polyethylene wax, for example, the "Sunwax (registered trademark)" series manufactured by Sanyo Chemical Industries, Ltd. and the "Hiwax (trade name)" series manufactured by Mitsui Chemicals, Inc. can be used. The surface protective layer 15 preferably contains polyethylene wax in a range of 1% by mass or more and 10% by mass or less, and 3% by mass or more and 6% by mass or less, based on the entire mass of the surface protective layer 15. It is more preferable that the content is within this range. When the polyethylene wax is contained within the above numerical range, stain resistance can be further improved while maintaining the basic functions of the surface protective layer 15 such as scratch resistance.

The surface protective layer 15 can also contain an antibacterial agent such as silver-supported phosphate, if necessary. The phosphate is not particularly limited as long as it is publicly known, but it includes at least one metal selected from the group consisting of silver, titanium, cerium, zirconium, germanium, potassium, aluminum, and gallium. preferable. It is also possible to apply isotopes of these metals. In particular, silver is preferable from the viewpoint of antibacterial ability. A known method is used to produce the phosphate. The antibacterial agent is contained in the surface protective layer 15 in an amount of 1×10 ^-4 mass % or more and 20 mass % or less.

The surface protective layer 15 can also contain various additives such as a heat stabilizer, an antiblocking agent, a catalyst scavenger, a coloring agent, and a fungicide, in order to have various other functions.

The method of forming the surface protective layer 15 is not particularly limited, but for example, the above-mentioned materials may be formed into a coating liquid, and a general method such as gravure coating, microgravure coating, comma coating, knife coating, or die coating may be used. After coating, it can be formed by curing by a means suitable for the material, such as heat curing or ultraviolet curing.

Considering manufacturing workability, cost, etc., the surface protective layer 15 preferably has a thickness of 1 μm or more and 20 μm or less, more preferably 2 μm or more and 15 μm or less.

The surface protective layer 15 has a peak intensity B of a maximum intensity wave number between 1700 cm ^-1 and 1800 cm ^-1 measured from the surface by Fourier transform infrared spectroscopy (FT-IR). The intensity ratio (intensity A/intensity B), which is the ratio of the peak intensity A of the wave number of the maximum intensity existing between 1800 cm ^-1 and 1850 cm ^-1 , is 0.01 or more. This intensity ratio is an index indicating the crosslinking density of the surface protective layer 15, and is a value determined as follows.

A sample is prepared by cutting the decorative sheet 10, and the FT-IR absorption spectrum of the surface of the surface protective layer 15 located on the outside of the sample is measured. From the obtained absorption spectrum, peak intensity A of the maximum intensity wavenumber derived from acid anhydride absorption exists between 1800 cm ^-1 and 1850 cm ^-1 , and carbonate exists between 1700 cm ^-1 and 1800 cm ^-1 . The peak intensity B of the maximum intensity wave number derived from bond absorption is determined, and the intensity ratio of the peak intensity A to the peak intensity B (intensity A/intensity B) is calculated to determine an index value Dc representing the crosslink density.

The index value Dc needs to be 0.01 or more, but from the viewpoint of scratch resistance and stain resistance, it is preferably 0.02 or more. Although there is no particular upper limit to the index value Dc, 0.2 or less is considered to be the de facto upper limit.

Methods for increasing the index value Dc to 0.01 or more include adjusting the functional group equivalents and content ratios of the polycarbonate urethane resin and the carbodiimide curing agent, and heating temperature and heating time during production of the decorative sheet 10. For example, crosslinking may be promoted by adjusting .

Further, the surface protective layer 15 preferably has a Martens hardness in the cross-sectional direction of 30 N/mm ² or more and 150 N/mm ² or less (temperature 23° C., humidity 50% RH). Martens hardness is a type of index that indicates the hardness (hardness) of a substance. Martens hardness is calculated by applying a load to the indenter, pushing the indenter into the surface of the sample, measuring the depth (indentation depth) of the indentation (indentation) formed on the sample, and calculating the indentation force from the load. , is defined as the value of the quotient of the surface area of the depression calculated from the indentation depth.

The Martens hardness is measured from the cross section of the decorative sheet 10 in order to avoid the influence of the resin layer laminated in addition to the surface protection layer 15. Specifically, a sample of the decorative sheet 10 is embedded in a resin such as a cold-curing epoxy resin or a UV-curing resin, and then sufficiently cured, and then cut so that a cross section of the decorative sheet 10 is exposed. The cut surface is mechanically polished to obtain a measurement surface. Then, an indenter is pressed into the surface protection layer 10, and the Martens hardness is calculated from the depth of indentation and the load. More specifically, the measurement method is defined in "ISO14577".

The Martens hardness is preferably 30 N/mm ² or more and 150 N/mm ² or less (temperature 23°C, humidity 50% RH), and 50 N/mm ² or more and 100 N/mm ² or less (temperature 23°C, humidity 50% RH). It is more preferable. When the Martens hardness is less than 30 N/mm ² , it becomes difficult to obtain sufficient scratch resistance, and when it exceeds 150 N/mm ² , it becomes difficult to obtain sufficient weather resistance and stain resistance. Put it away.

The method of adjusting the Martens hardness includes adjusting the functional group equivalent and content ratio of the polycarbonate urethane resin and the carbodiimide curing agent, adjusting the particle size and content of the filler, and adjusting the content during the production of the decorative sheet 10. Examples include promoting crosslinking by adjusting the heating temperature and heating time.

<Primer layer 19>
The primer layer 19 is provided to adhere the decorative sheet 10 to an object to be adhered. The material constituting the primer layer 19 is not particularly limited, and may be selected from resin materials such as urethane-based, acrylic-based, acrylic-silicon-based, fluorine-based, epoxy-based, and polyester-based, depending on the adhesion to the adherend. Materials with excellent properties can be appropriately selected and applied.

<Method for manufacturing decorative sheets>
Next, a method for manufacturing the decorative sheet 10 according to the present embodiment described above will be explained.
First, the pattern layer 12 is printed and formed on the base material layer 11 (pattern layer forming step), and then the adhesive layer 13 is applied and formed on the pattern layer 12 (adhesive layer forming step). Subsequently, a transparent resin layer 14 is formed on the adhesive layer 13 by extrusion molding (transparent resin layer forming step). Finally, a surface protective layer 15 is formed on the transparent resin layer 14 (surface protective layer forming step).

Here, in the surface protective layer forming step, an index value Dc, which is the ratio of the peak intensity A to the peak intensity B (intensity A/intensity B) measured from the surface by the FT-IR method, is 0.01. A surface protective layer 15 containing the product obtained by reacting a polycarbonate urethane resin with a carbodiimide curing agent as a main component is provided on the transparent resin layer 14 so as to form the above product.

In addition, in the transparent resin layer forming step, it is preferable to treat the surface of the transparent resin layer 14 so that the surface of the transparent resin layer 14 has a wettability index of 60 dyne or more. Note that the wetting index of the surface of the transparent resin layer 14 can be confirmed using a so-called "wetting reagent."

In addition, in the adhesive layer forming step and the surface protective layer forming step, it is possible to form a layer by applying a printing method such as gravure printing, flexographic printing, or inkjet printing.

In the decorative sheet 10 according to the present embodiment manufactured in this manner, the surface protective layer 15 contains a reaction product of a polycarbonate urethane resin and a carbodiimide curing agent, and the index value Dc is 0. 01 or more, it is possible to improve scratch resistance, stain resistance, and weather resistance.

Furthermore, in the decorative sheet 10 according to the present embodiment, since the Martens hardness is 30 N/mm ² or more and 150 N/mm ^{2 or} less, scratch resistance, stain resistance, and weather resistance can be further improved.

Examples of the decorative sheet and the method for manufacturing the same according to the present invention will be described below, but the present invention is not limited to the examples described below.

[Preparation of test specimen and comparison specimen]
<Test specimen 1>
《Preparation of material for surface protective layer》
A material for the surface protective layer was prepared according to the following formulation.
・Resin: 100 parts by mass of polycarbonate urethane resin “Takelac (registered trademark) W-6010 (product number)” manufactured by Mitsui Chemicals Co., Ltd. ・Curing agent: Carbodiimide curing agent “Carbodilite (registered trademark) SV-02 manufactured by Nisshinbo Chemical Co., Ltd.” (Product number)" 10 parts by mass Filler: Mizusawa Chemical Co., Ltd. "Mizukasil (registered trademark) P-803 (Product number)" 2.5 parts by mass (particle size 5 μm)
- Ultraviolet absorber: 1 part by mass of "Tinuvin (registered trademark) 400DW (product number)" manufactured by BASF Japan Ltd. - Light stabilizer: 1 part by mass of "Tinuvin (registered trademark) 123DW (product number)" manufactured by BASF Japan Ltd.

《Preparation of decorative sheet》
A 55 μm polyethylene sheet with hiding properties was used as the base layer. A two-component curing urethane ink (manufactured by Toyo Ink Co., Ltd., "V180 (product number)") was printed on one side of the base layer using a gravure printing method to form a pattern layer (thickness: 3 μm), and on the other side of the base layer. A primer layer made of the same resin component as the pattern layer was provided. An adhesive layer (thickness: 2 μm) was provided by printing a dry laminating adhesive (“Takelac (registered trademark) A540 (product number)” manufactured by Mitsui Chemicals, Inc.) on the surface of the pattern layer using a gravure printing method.

Next, polypropylene resin (containing 0.5% by mass of benzophenone ultraviolet absorber and 0.5% by mass of hindered amine light stabilizer) was extruded onto the surface of the adhesive layer using an extrusion lamination method to form a transparent resin layer (thickness: 70 μm). Established. Subsequently, a surface protective layer (thickness: 7 μm) was provided by coating the surface of the transparent resin layer with the material for the surface protective layer using a gravure coating method, thereby producing a decorative sheet test piece 1.

<Test specimen 2>
A decorative sheet test specimen was made the same as test specimen 1, except that the hardening agent for the material for the surface protective layer was changed to a carbodiimide hardening agent “Carbodilite (registered trademark) V-04 (product number)” manufactured by Nisshinbo Chemical Co., Ltd. 2 was produced.

<Test specimen 3>
A decorative sheet test specimen was made the same as test specimen 1 except that the hardening agent for the material for the surface protective layer was changed to a carbodiimide hardening agent “Carbodilite (registered trademark) E-02 (product number)” manufactured by Nisshinbo Chemical Co., Ltd. 3 was prepared.

<Test specimen 4>
Test sample 4 of the decorative sheet was the same as test sample 1 except that the resin for the surface protective layer was changed to polycarbonate-based urethane resin "Takelac (registered trademark) WS-5100 (product number)" manufactured by Mitsui Chemicals. was created.

<Test specimen 5>
The resin for the surface protective layer material was changed to polycarbonate urethane resin "Takelac (registered trademark) WS-5100 (product number)" manufactured by Mitsui Chemicals Co., Ltd., and the hardening agent for the surface protective layer material was changed to Nisshinbo Chemical Co., Ltd. A decorative sheet test specimen 5 was prepared in the same manner as test specimen 1 except that the carbodiimide curing agent "Carbodilite (registered trademark) V-04 (product number)" was used.

<Test specimen 6>
The resin for the surface protective layer material was changed to polycarbonate urethane resin "Takelac (registered trademark) WS-5100 (product number)" manufactured by Mitsui Chemicals Co., Ltd., and the hardening agent for the surface protective layer material was changed to Nisshinbo Chemical Co., Ltd. A decorative sheet test specimen 6 was prepared in the same manner as test specimen 1 except that the carbodiimide curing agent "Carbodilite (registered trademark) E-02 (product number)" was used.

<Test specimen 7>
Same as test specimen 1 except that the hardening agent for the surface protective layer material was changed to carbodiimide hardening agent "Carbodilite (registered trademark) E-02 (product number)" manufactured by Nisshinbo Chemical Co., Ltd. and the amount added was changed to 5 parts by weight. A decorative sheet test specimen 7 was prepared.

<Test specimen 8>
Test sample 8 of the decorative sheet was the same as test sample 1 except that the resin for the surface protective layer material was changed to polycarbonate-based urethane resin "Takelac (registered trademark) WS-4000 (product number)" manufactured by Mitsui Chemicals. was created.

<Test specimen 9>
The resin for the surface protective layer material was changed to polycarbonate urethane resin "Takelac (registered trademark) WS-4000 (product number)" manufactured by Mitsui Chemicals Co., Ltd., and the curing agent for the surface protective layer material was changed to Nisshinbo Chemical Co., Ltd. A decorative sheet test specimen 9 was prepared in the same manner as test specimen 1 except that the carbodiimide curing agent "Carbodilite (registered trademark) E-02 (product number)" was used.

<Test specimen 10>
A decorative sheet specimen 10 was prepared in the same manner as the specimen 1 except that the filler material for the surface protective layer was omitted.

<Comparative body 1>
Comparative decorative sheet, same as test specimen 1 except that the hardening agent for the material for the surface protective layer was changed to carbodiimide hardening agent "Carbodilite (registered trademark) E-05 (product number)" manufactured by Nisshinbo Chemical Co., Ltd. 1 was produced.

<Comparative body 2>
A comparative decorative sheet 2 was prepared in the same manner as the test specimen 1 except that the content of the curing agent in the material for the surface protective layer was changed to 1 part by mass.

<Comparative body 3>
A comparative decorative sheet 3 was prepared in the same manner as the test specimen 1 except that the content of the curing agent in the material for the surface protective layer was changed to 3 parts by mass.

<Comparison 4>
A comparative decorative sheet 4 was prepared in the same manner as the test specimen 1 except that the content of the curing agent in the material for the surface protective layer was changed to 25 parts by mass.

<Comparative body 5>
Comparative decorative sheet 5 was made the same as test specimen 1 except that the resin for the surface protective layer was changed to polycarbonate urethane resin "Takelac (registered trademark) W-6110 (product number)" manufactured by Mitsui Chemicals Co., Ltd. was created.

<Comparison 6>
A decorative sheet comparison sample, which was the same as test sample 1 except that the resin for the surface protective layer was changed to polyether urethane resin "Takelac (registered trademark) W-6061 (product number)" manufactured by Mitsui Chemicals. 6 was produced.

[Physical property measurement]
<FT-IR peak intensity ratio>
"Measuring method"
Samples are prepared by cutting the above-described test specimens 1 to 10 and comparative specimens 1 to 6, and the FT-IR absorption spectrum of the surface of the surface protective layer located on the outside of the sample is measured. From the obtained absorption spectrum, peak intensity A of the maximum intensity wavenumber derived from acid anhydride absorption exists between 1800 cm ^-1 and 1850 cm ^-1 , and carbonate exists between 1700 cm ^-1 and 1800 cm ^-1 . The peak intensity B of the maximum intensity wave number derived from bond absorption is determined, and the intensity ratio (intensity A/intensity B), which is the ratio of peak intensity A to peak intensity B, is calculated to obtain the index value Dc representing the crosslink density. I asked for it.

"Measurement condition"
・Sample shape: 50mm x 50mm (square)
・FT-IR device: “FT/IR6300 (product number)” manufactured by JASCO Corporation
・Measurement mode: Total reflection measurement (ATR) mode ・Number of reflections: 1 reflection ・ATR prism: Diamond ・Temperature: 25℃
・Relative humidity: 50%
・Wavenumber resolution: 4cm ^-1
・Accumulated number of times: 160 times

<Martens hardness>
"Measuring method"
It was measured based on the regulations of "ISO14577". That is, samples of test specimens 1 to 10 and comparative specimens 1 to 6 were embedded in cold-curing epoxy resin and sufficiently cured, then cut to expose the cross section of the sample, and machined on the cut surface. By polishing the measurement surface, it is possible to avoid the effects of layers other than the surface protective layer. Then, in an environment of a temperature of 23° C. and a humidity of 50% RH, an indenter was pressed into the surface protective layer of the sample using a Martens hardness measuring device, and the Martens hardness was calculated from the pressing depth and load.

"Measurement condition"
・Measuring device: Manufactured by Fisher Instruments Co., Ltd.
"FISCHERSCOPE (registered trademark) HM2000 (product number)"
・Test force: 10mN
・Test force loading time: 10 seconds ・Test force holding time: 5 seconds

[contents of the test]
<Scratch resistance test>
"Test method"
A scratch hardness test was conducted on the samples of test specimens 1 to 10 and comparative specimens 1 to 6 using a Hoffman scratch hardness tester manufactured by BYK-Gardner, USA, to confirm scratch resistance. That is, a load from 100 g to 1000 g was sequentially applied to the sample in 100 g increments, and the load at which a scratch occurred on the sample was determined by visual observation.

"Evaluation criteria"
Evaluation was made as follows based on the load when scratches occurred.
〇: 500g load or more △: 200g load or more and 400g load or less ×: 100g load

<Stain resistance test>
"Test method"
A reagent (1% aqueous sodium hydroxide solution) was dropped onto the surface of the samples of test specimens 1 to 10 and comparative specimens 1 to 6, and the surface conditions of the samples were visually observed after being left for 24 hours.

"Evaluation criteria"
Based on the results of visual observation, evaluation was made as follows.
〇: No trace △: Slight trace ×: Clear trace due to dissolution

<Weather resistance test>
"Test method"
The samples of test specimens 1 to 10 and comparative specimens 1 to 6 were subjected to weather resistance tests under the following conditions using an accelerated weather resistance tester "Atlas Weatherometer (registered trademark) Ci4000 (product number)" manufactured by Toyo Seiki Seisakusho Co., Ltd. The condition of the sample after the test was visually observed.

"Test condition"
・Irradiation light: xenon arc lamp 180W
・Rainfall time: 12 minutes ・Rainfall cycle: 120 minutes cycle ・Test time: 500 hours

"Evaluation criteria"
Based on the results of visual observation, evaluation was made as follows.
○: No change before and after the test.
Δ: Some whitening spots were observed in the sample after the test.
×: Peeling areas or whitening areas were observed in a wide range in the sample after the test.

[Test results]
The settings of test specimens 1 to 10 and comparative specimens 1 to 6 are shown in "Table 1" below, and the test results are shown in "Table 2" below. In addition, in "Table 2", "〇" and "△" are considered "suitable", and "x" is "unsuitable".

As can be seen from Tables 1 and 2, Comparatives 1 to 6 were found to be "unsuitable" in any one of scratch resistance, stain resistance, and weather resistance. On the other hand, test specimens 1 to 10 were ``suitable'' in all of scratch resistance, weather resistance, adhesion, and workability.

From the above results, it was confirmed that the present invention can improve the scratch resistance, stain resistance, and weather resistance of decorative sheets.

The decorative sheet and the manufacturing method thereof according to the present invention can improve scratch resistance, stain resistance, and weather resistance, so it is suitable for use on the interior and exterior of buildings, fittings, furniture, etc., and is extremely useful in industry. It can be used beneficially.

10 Decorative sheet 11 Base layer 12 Pattern layer 13 Adhesive layer 14 Transparent resin layer 15 Surface protection layer 19 Primer layer

Claims (11)

A base material, a pattern layer provided on the base material, an adhesive layer provided on the pattern layer, a transparent resin layer provided on the adhesive layer, and a surface protection layer provided on the transparent resin layer. In a decorative sheet with
(1) The surface protective layer mainly contains a reaction product of a polycarbonate urethane resin and a carbodiimide curing agent,
(2) 1800 cm ^-1 and 1850 cm ^-1 with respect to the peak intensity B of the wave number of the maximum intensity existing between 1700 cm ^-1 and 1800 cm ^-1 measured from the surface of the surface protective layer by infrared spectroscopy A decorative sheet characterized in that the ratio of the peak intensity A of the wave number of the maximum intensity existing between the two (intensity A/intensity B) is 0.01 or more. The decorative sheet according to claim 1, wherein the surface protective layer has a Martens hardness of 30 N/mm ² or more and 150 N/mm ^{2 or} less in a cross-sectional direction. The decorative sheet according to claim 1, wherein the surface protective layer has a thickness of 2 μm or more and 15 μm or less. The decorative sheet according to claim 1, wherein the surface protective layer contains a filler. The decorative sheet according to claim 4, wherein the filler is silica particles. The decorative sheet according to claim 1, wherein the surface protective layer contains an ultraviolet absorber. The decorative sheet according to claim 1, wherein the surface protective layer contains a light stabilizer. The decorative sheet according to claim 1, wherein the surface protective layer is formed from an aqueous composition. The decorative sheet according to any one of claims 1 to 8, wherein the transparent resin layer is an olefin resin. The decorative sheet according to any one of claims 1 to 8, wherein the adhesive layer contains a polyurethane resin. a pattern layer forming step of providing a pattern layer on the base material; an adhesive layer forming step of providing an adhesive layer on the pattern layer; a transparent resin layer forming step of providing a transparent resin layer on the adhesive layer; In a method for manufacturing a decorative sheet, the method includes a surface protective layer forming step of providing a surface protective layer on the layer,
The surface protective layer forming step includes:
The maximum intensity present between 1800 cm ⁻¹ and 1850 cm ⁻¹ relative to the peak intensity B of the wavenumber of the maximum intensity present between 1700 cm ⁻¹ and 1800 cm ⁻¹ measured from the surface by infrared spectroscopy The product obtained by reacting a polycarbonate urethane resin and a carbodiimide curing agent such that the ratio of peak intensity A at the wave number (Intensity A/Intensity B) is 0.01 or more. A method for producing a decorative sheet, comprising the step of providing the surface protective layer containing as a main component on the transparent resin layer.

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