JP7052731B2 - Laminated stretch film, base material for decorative sheet, decorative sheet and decorative board - Google Patents

Description

The present invention relates to a laminated stretch film, a base material for a decorative sheet, a decorative sheet and a decorative board.

Among decorative sheets used for building interior materials and the surface of fittings, especially for decorative sheets used for public use, non-combustible materials described in Article 108-2, Items 1 and 2 of the Building Standards Act Enforcement Ordinance. It is required to meet the technical standards of. Conventionally, a decorative sheet using a soft polyvinyl chloride resin has been used as a decorative sheet satisfying the technical standards for such non-combustible materials. However, the decorative sheet using the soft polyvinyl chloride resin has a problem that toxic gas or the like is generated during the incineration treatment after disposal.
Therefore, a decorative sheet using a polyolefin resin instead of the polyvinyl chloride resin has been proposed. However, when a polyolefin-based resin is used, although the generation of toxic gas and the like during combustion is suppressed, the polyolefin-based resin has excellent combustibility, so that it is a technical standard for non-combustible materials. It was difficult to meet.

Examples of the decorative sheet using the polyolefin resin that satisfies the technical standards for non-combustible materials described in the above-mentioned laws and regulations include the decorative sheets described in Patent Documents 1 and 2. Patent Documents 1 and 2 disclose a structure using a polyolefin-based resin layer containing an inorganic filler such as calcium carbonate.

Japanese Unexamined Patent Publication No. 2013-01931 Japanese Unexamined Patent Publication No. 2011-122293

Here, as a method for obtaining a decorative sheet made of a polyolefin resin that satisfies the above technical standards for non-combustible materials, for example, a method for thinning the base material of the decorative sheet can be mentioned. Further, in general, a printing layer is provided on the surface side of the base material in order to impart designability to the decorative sheet. At this time, when the base material is put into the printing machine, the base material is required to have sufficient mechanical strength in order to suppress the occurrence of the deviation of the printing position.
In order to cope with the above, if a stretched film subjected to uniaxial stretching or biaxial stretching is adopted as the base material for the decorative sheet, the base material for the decorative sheet is thinned and the nonflammability of the decorative sheet is enhanced at the same time. It is possible to increase the mechanical strength of the base material for a decorative sheet and further the decorative sheet.

However, when the base material is stretched, the surface uneven shape of the base material becomes smooth, so that the anchor effect is lowered and the adhesion between the printed layer and the surface of the base material is lowered. When the adhesion between the surface of the base material and the printing layer is lowered, the peel strength between the transparent resin layer formed on the base material via the printing layer and the base material may be significantly lowered. At this time, by forming surface irregularities on the base material by embossing and imparting an anchor effect to the surface of the base material, the adhesion between the printed layer and the base material can be improved. However, if the embossing treatment is performed at a processing temperature that enables embossing deformation, the orientation with respect to stretching is relaxed, and the effect of improving the strength by stretching may decrease.

Achieving both improvement in peel strength and improvement in strength by stretching is an issue in obtaining a decorative sheet having both substrate strength and durability.
The present invention has been made by paying attention to the above points, and is a laminated stretched film having both strength and durability of a base material, a base material for a decorative sheet provided with the laminated stretched film, and a base material for the decorative sheet. It is an object of the present invention to provide a decorative sheet provided with a decorative sheet and a decorative board provided with the decorative sheet.

In order to solve the problem, the laminated stretched film according to one aspect of the present invention is a uniaxial or biaxial laminated stretch film having a plurality of layers of a thermoplastic resin, and the plurality of thermoplastic resins thereof. When the first layer located on the outermost surface of the layers is defined as the surface layer, the melting point of the resin of the surface layer is 20 ° C. or higher as compared with the melting point of the resin of the thermoplastic resin layer other than the surface layer. low.
Further, the decorative sheet according to one aspect of the present invention is a one-layer or a plurality of transparent resin layers containing the above-mentioned base material for a decorative sheet and a polyolefin-based resin formed on the surface of the base material for a decorative sheet on the surface layer side. And prepare.

According to one aspect of the present invention, a laminated stretched film having both strength and durability of a base material, a base material for a decorative sheet provided with the laminated stretched film, a decorative sheet provided with the base material for the decorative sheet, and a decorative sheet thereof. You can get a veneer with.
That is, since it is a stretched film, it is possible to simultaneously increase the thinning of the base material and the mechanical strength.
At this time, when the film is stretched, the surface of the film as a base material is crystallized, and the wet affinity of the ink with respect to the base material (how much the ink soaks into the original fabric) is lowered, so that the ink and the base are formed. Adhesion with the material may decrease. On the other hand, according to one aspect of the present invention, the layer of the thermoplastic resin constituting the stretched film is multi-layered, and the melting point of the surface layer is lowered by 20 degrees or more from the melting point of the other layers to form the surface layer. The degree of crystallinity is reduced and the adhesion with the ink (printing layer) is maintained. As a result, durability as a decorative sheet can be ensured without necessarily embossing.
Further, since the base material can be thinned by stretching, it is possible to improve the nonflammability.

It is sectional drawing which shows one structural example of the decorative sheet which concerns on embodiment of this invention.

An embodiment of the present invention will be described with reference to FIG.
Here, the configuration shown in FIG. 1 below is a schematic one, and the relationship between the thickness and the plane dimension, the ratio of the thickness of each layer, and the like are different from the actual ones. Further, the embodiments shown below exemplify a configuration for embodying the technical idea of the present invention, and the technical idea of the present invention describes the materials, shapes, structures, etc. of the constituent parts as follows. It is not specific to things. The technical idea of the present invention may be modified in various ways within the technical scope specified by the claims described in the claims.

FIG. 1 is a cross-sectional view showing the configuration of the decorative sheet 1 according to the present embodiment. The decorative sheet 1 is printed on a decorative sheet base material 6 (hereinafter, also referred to as a base material 6) composed of a laminate containing a plurality of thermoplastic resin layers and one surface (surface) of the base material 6. The layer 5, the adhesive layer 4, the transparent resin layer 3 and the surface protective layer 2 are formed in this order. Further, the decorative sheet 1 is provided with a concealing layer 7 and a primer layer 8 on the other surface (back surface) of the base material 6.
Here, the base material 6 has at least a first base material layer 6-1 (hereinafter referred to as a surface layer 6-1) which is the outermost surface and a second base material layer different from the surface layer 6-1. It comprises at least one of 6-2 to nth base layer 6-n. That is, the base material 6 has n pieces from the surface layer 6-1 and the second base material layer 6-2 to the nth base material layer 6-n (n is an arbitrary positive integer of 2 or more). It is formed of a base layer of.

When the base material 6 is composed of two layers, the surface layer 6-1 and the second base material layer 6-2, the back surface of the second base material layer 6-2 is the other surface of the base material 6. ..
The concealing layer 7 may be formed between the base material 6 and the printing layer 5, or may be omitted. In particular, in the present embodiment, since the inorganic pigment is mixed with the base material 6 as described later, there is no design problem even if the concealing layer 7 is omitted. When the amount of pigment mixed in the base material 6 is suppressed to a small amount, it is preferable to provide the concealing layer 7 as needed.
The thickness of the decorative sheet 1 is preferably in the range of, for example, 49 μm or more and 360 μm or less. When the thickness of the decorative sheet 1 is within this range, the printing workability at the time of manufacturing the decorative sheet 1 can be improved, and the manufacturing cost can be suppressed.
Such a decorative sheet 1 constitutes a decorative plate by attaching the surface on the primer layer 8 side to a base plate 9 made of, for example, a wood substrate.
Hereinafter, each part of the decorative sheet 1 will be described in detail.

<Base material>
The base material 6 is made of a laminated stretched film thinned by uniaxial stretching or biaxial stretching from the viewpoint of nonflammability. The thickness of the base material 6 is preferably 20 μm or more and less than 60 μm, and more preferably 20 μm or more and 40 μm or less. When the thickness of the base material 6 is in the range of 20 μm or more and less than 60 μm, both the nonflammability of the decorative sheet 1 and the mechanical properties (strength) can be achieved. Further, when the thickness of the base material 6 is in the range of 20 μm or more and 40 μm or less, it is more preferable because the nonflammability is further improved.

The non-combustibility of the base material 6 is the heat generated by the cone calorie meter tester compliant with ISO5660-1 in a state where the substrate to which the decorative sheet is attached is attached to a non-combustible base material (not shown) made of a metal plate or an inorganic material. In the sex test, it is preferable that the property is nonflammable enough to satisfy the requirements described in Article 108-2, Items 1 and 2 of the Building Standards Act Enforcement Ordinance.
Each layer constituting the base material 6 is formed of a resin material and contains a thermoplastic resin as a main component of the resin material. The main component means, for example, a resin material containing 100 parts by mass or more of the resin material constituting the layer and 70 parts by mass or more and 100 parts by mass or less, preferably 90 parts by mass or more and 100 parts by mass or less.

(Melting point of substrate 6)
The surface layer 6-1 of the base material 6 contains a thermoplastic resin having a melting point at least 20 ° C. or higher lower than that of the other base material layers 6-2 to 6-n. By setting the difference in melting point of the resin to be 20 ° C. or higher, when embossing the substrate, the temperature at which the surface layer is embossed is such that the substrate layers 6-2 to 6-n other than the surface layer are embossed. The orientation can be maintained to some extent. Therefore, the interlayer adhesion between the surface layer 6-1 and the transparent resin layer 3 can be improved while maintaining the effect of improving the strength of the base material by stretching.

Even when the surface layer 6-1 is not embossed, the crystallinity of the surface layer 6-1 is reduced by lowering the melting point of the surface layer 6-1 by 20 degrees or more from the melting points of the other layers. As a result of maintaining the adhesion with the ink (printing layer), the interlayer adhesion between the surface layer 6-1 and the transparent resin layer 3 is ensured.
Here, if the same type of resin is used, the lower the melting point, the more difficult it is for crystallization to proceed. For example, the melting point of highly crystalline polypropylene is about 160 ° C. and crystallization is easy to proceed, but the melting point of low density polyethylene is about 130 to 145 ° C. and crystallization is relatively difficult to proceed.

On the other hand, the difference between the melting point of the thermoplastic resin contained in the second base material layer 6-2 to the nth base material layer 6-n and the melting point of the thermoplastic resin contained in the surface layer 6-1 is 20 ° C. If it is less than, the ink adhesion between the base material 6 and the printing layer 5 is improved when the surface layer 6-1 is embossed, but the layers of the base material layers 6-2 to 6-n are stretch-oriented. The effect of relaxing the orientation of the base material 6 is increased, and the effect of improving the strength of the base material 6 by stretching is reduced.
Here, in order for the surface layer 6-1 to be a combination of a thermoplastic resin having a melting point of at least 20 ° C. or higher lower than that of the other base layers 6-2 to 6-n, for example, the surface layer 6-1 is used. It is realized by being composed of low-density polyethylene and the other base layer 6-2 to 6-n being composed of highly crystalline polypropylene.

(Resin material and soft material)
At least one layer constituting the base material 6, that is, another base material layer different from the surface layer 6-1 and the surface layer 6-1 (second base material layer 6-2 to nth base material layer 6-n). ) At least one layer preferably contains a polyolefin resin. Polymer-based resins include, in addition to polyethylene, polypropylene, polybutene, etc., α-olefins (eg, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonen, 1-decene). , 1-Undecene, 1-Dodecene, Tridecene, 1-Tetradecene, 1-Pentadecene, 1-Hexadecene, 1-Heptadesen, 1-Octadecene, 1-Nonadecene, 1-Eikosen, 3-Methyl-1-butene, 3-Methyl -1-Pentene, 3-Ethylene-1-Pentene, 4-Methyl-1-Pentene, 4-Methyl-1-hexene, 4,4-dimethyl-1-Pentene, 4-Ethylene-1-Hexene, 3-Ethylene 1-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc.) are homopolymerized or copolymerized in two or more types, or ethylene / vinyl acetate copolymer weight. Combined, ethylene / vinyl alcohol copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl methacrylate copolymer, ethylene / butyl methacrylate copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, Examples thereof include those obtained by copolymerizing ethylene or α-olefin with other monomers such as an ethylene / butyl acrylate copolymer. In particular, from the viewpoint of price and processability, it is preferable to select and use at least one of polyethylene and polypropylene as the polyolefin resin. Further, in order to improve the tensile elastic modulus of the base material 6, it is preferable to use highly crystalline polypropylene. In this embodiment, the resin group containing polypropylene and its derivative is referred to as "polypropylene resin".

Further, the surface layer 6-1 may contain a resin material having low crystallinity as a soft material in order to improve the embossing processability. As the surface layer 6-1, it is preferable to use, for example, a polyolefin resin having a mesopentad fraction of 30% or more and less than 50% as the soft material. Specifically, as the soft material, for example, it is particularly preferable to use a polypropylene resin having a mesopentad fraction in the range of 30% or more and less than 50%, particularly a low crystalline polypropylene resin.
When the surface layer 6-1 contains a soft material, the surface layer 6-1 contains 5 parts by mass or more and 30 parts by mass with respect to 100 parts by mass of the main component resin (base resin) constituting the surface layer 6-1. It is preferably formed of a mixed resin mixed in an amount of less than a portion. When the mixing amount of the soft material is less than 5 parts by mass, the soft effect due to the mixing of the soft material is unlikely to appear. Further, when the mixing amount of the soft material is 30 parts by mass or more, the soft effect due to the mixing of the soft material appears, but the stickiness of the surface layer 6-1 becomes a problem due to the heat treatment during the stretching of the base material 6. There is.
Further, from the viewpoint of the uniformity of the resin material forming the surface layer 6-1, the soft material is preferably a material having high compatibility with the resin material forming the surface layer 6-1. From this point of view, for example, when the surface layer 6-1 is made of polypropylene resin, it is desirable that the soft material to be mixed is also polypropylene resin.

(About surface roughness on the base material)
The adhesion between the surface layer 6-1 of the decorative sheet base material 6 and the printing layer 5 formed on the surface layer 6-1 of the decorative sheet base material 6 depends on the roughness of the surface of the base material 6. improves. However, since the roughness of the surface of the base material 6 is reduced by the uniaxial or biaxial stretching, the stretched base material adheres to the printing layer as compared with the non-stretched base material. The sex is reduced. Therefore, from the viewpoint of improving the adhesion between the base material 6 and the printing layer 5, it is desirable to provide the base material 6 after stretching with an appropriate surface roughness. The surface roughness index on the preferred substrate 6 is in the range where the maximum valley depth Rv is 5 μm or more and 10 μm or less. If Rv is less than 5 μm, the anchoring effect of adhering the substrate and the printed layer is lowered, so that an appropriate peel strength test result cannot be obtained. Further, if Rv is more than 10 μm, the gloss value of the print layer is greatly affected and the design required for the decorative sheet changes, which is not preferable.

(About embossing method)
The embossing process is performed by crimping the embossing roll to the base material 6, and the roughness corresponding to the shape on the embossing roll can be imparted to the surface of the base material 6. At the time of embossing, the embossing roll temperature must be higher than the temperature at which the base material 6 is sufficiently thermally deformed. In particular, in the present application, although the surface layer 6-1 of the base material 6 is deformed, the surface layer 6- It is desirable that the temperature is below the temperature at which the substrate layers 6-2 to 6-n other than 1 are deformed. The appropriate embossing roll temperature for the resin is not uniquely determined because it is affected by the pressure during crimping, but under a certain pressure, it is the melting point of the resin constituting each layer of the base material 6. Therefore, if the melting point of the surface layer 6-1 of the base material 6 is designed to be 20 ° C. or more lower than the melting points of the other layers 6-2 to 6-n as in the present application, the surface layer of the base material 6 is correlated. At the temperature at which the embossed roll surface structure begins to be transferred to 6-1 the substrate layers 6-2 to 6-n other than the surface layer 6-1 are not deformed or the amount of deformation is suppressed to a small value.

(Inorganic pigment)
At least one layer constituting the base material 6, that is, a base material layer different from the surface layer 6-1 and the surface layer 6-1 (second base material layer 6-2 to nth base material layer 6-n). The at least one layer preferably contains an inorganic pigment. By containing the inorganic pigment, the light transmittance of the base material 6 is lowered, and the pattern of the base material plate 9 to which the decorative sheet 1 is attached can be prevented from being transmitted.
The mixing amount of the inorganic pigment is preferably 5 vol% or more and 50 vol% or less with respect to the resin material in each of the surface layer 6-1 and the other base layer 6-2 to 6-n. When the mixing amount of the inorganic pigment is 5 vol% or more and 50 vol% or less, the effect of improving the nonflammability by adding the inorganic pigment is exhibited, and the embrittlement of the base material 6 due to the excessive amount of the inorganic pigment added is also suppressed. This is because it can be done.

The inorganic pigment contained in at least one layer constituting the base material 6 is not particularly limited, and examples thereof include natural inorganic pigments and synthetic inorganic pigments.
Examples of natural inorganic pigments include earth-based pigments, calcined soil, and mineral pigments. Examples of synthetic inorganic pigments include oxide pigments, hydroxide pigments, sulfide pigments, silicate pigments, phosphate pigments, carbonate pigments, metal powder pigments, carbon pigments and the like. Further, a mixed pigment of one kind or a mixture of two or more kinds from natural inorganic pigments and synthetic inorganic pigments may be used.
It is not preferable to use an organic pigment as the pigment. This is because the nonflammability of the base material 6 is impaired.

The base material 6 preferably has a light transmittance in the range of 0% or more and 40% or less in order to obtain the concealing property required from the viewpoint of the design of the decorative sheet 1. When the light transmittance exceeds 40%, sufficient concealing property cannot be obtained to bring out the design of the decorative sheet 1. Sufficient concealment cannot be obtained, for example, in a decorative board in which the surface of the decorative sheet 1 on the primer layer 8 side is attached to a base plate 9 made of a wood base material or the like, a base material such as a wood base material is used. It means that the pattern on the surface of the plate 9 facing the primer layer 8 is visible from the surface protective layer 2 side via the decorative sheet 1. When visually recognizable, the design of the print layer 5 and the pattern of the base plate 9 such as a wood base material may overlap and be visually recognized.

<Print layer>
The print layer 5 is a layer on which a pattern is formed in order to impart designability. The printing layer 5 can be provided on the surface layer 6-1 of the decorative sheet base material 6 by using a known printing method. When the base material 6 can be prepared in a wound state, printing for forming the printing layer 5 can be performed by a roll-to-roll printing apparatus. The printing method is not particularly limited, but a gravure printing method can be used, for example, in consideration of productivity and the quality of the pattern.
As the pattern, any pattern may be adopted in consideration of the design according to the place of use such as the floor material and the wall material. For example, in order to obtain a decorative sheet 1 having a wood-based pattern, various wood grain patterns are often preferably used as the pattern, and a cork pattern may be used in addition to the wood grain pattern. Further, in the case of obtaining the decorative sheet 1 in the image of a stone floor such as marble, marble stones or the like are used for the pattern. In addition to the patterns of natural materials, artificial patterns such as artificial patterns and geometric patterns using them as motifs are used as the pattern of the print layer 5.

The printing ink used to form the printing layer 5 is not particularly limited, but an ink corresponding to the printing method is appropriately selected. In particular, it is preferable that the printing ink is selected in consideration of the adhesion to the base material 6, the printability, the weather resistance of the decorative sheet 1, and the like.
Colorants such as pigments and dyes, extender pigments, solvents, and binders contained in ordinary inks are appropriately added to the printing inks. Examples of the pigment include condensed azo, insoluble azo, quinacridone, isoindoline, anthracinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, pearl pigments such as mica, and the like. The binder may be an aqueous type, a solvent type, or an emulsion type, and the curing method is particularly limited to a one-component type, a two-component type consisting of a main agent and a curing agent, or a type that is cured by ultraviolet rays or electron beams. It's not something to do. Among them, the most common method is a two-component type, which uses a urethane-based main agent and a curing agent composed of isocyanate. In addition to this, the design may be applied by vapor deposition or sputtering of various metals.
The thickness of the print layer 5 is preferably 3 μm or more and 20 μm or less. When the thickness of the printing layer 5 is within this range, printing can be clarified, printing workability at the time of manufacturing the decorative sheet 1 can be improved, and manufacturing cost can be suppressed.

<Adhesive layer>
The adhesive layer 4 is provided for the purpose of strengthening the adhesion between the base material 6 and the printing layer 5 and the transparent resin layer 3. The strong adhesion between the base material 6 and the printing layer 5 and the transparent resin layer 3 makes it possible to impart bending workability to the decorative sheet 1 so as to follow a curved surface or a right-angled surface. The adhesive layer 4 is preferably transparent.
The adhesive layer 4 is formed of, for example, an acrylic adhesive, a polyester adhesive, a polyurethane adhesive, an epoxy adhesive, or the like. As the adhesive constituting the adhesive layer 4, it is usually preferable to use a two-component curable type due to its cohesive force, particularly a urethane-based material obtained by reaction with a polyol using isocyanate. The adhesive layer 4 may be omitted if sufficient adhesive strength between the transparent resin layer 3 and the printing layer 5 can be obtained.

Any method can be selected as the bonding method between the base material 6 and the printing layer 5 via the adhesive layer 4 and the transparent resin layer 3, and for example, a laminating method by thermal laminating, extrusion laminating, dry laminating or the like can be selected. Can be mentioned.
The thickness of the adhesive layer 4 is preferably 1 μm or more and 20 μm or less. When the thickness of the adhesive layer 4 is within this range, the adhesive strength between the base material 6 and the printing layer 5 and the transparent resin layer 3 is improved, and the printing workability at the time of manufacturing the decorative sheet 1 is improved. Moreover, the manufacturing cost can be suppressed.

<Transparent resin layer>
The transparent resin layer 3 is composed of, for example, a transparent resin sheet, and is adhered to the base material 6 and the printing layer 5 by the adhesive layer 4. In the decorative sheet 1 shown in FIG. 1, the case where the transparent resin layer 3 is one layer is shown, but a plurality of transparent resin layers 3 may be laminated. The transparent resin layer 3 of the present embodiment is preferably composed of a polyolefin resin as a main component. The main component is, for example, a resin material containing 100 parts by mass of the resin material constituting the base material 6 and 70 parts by mass or more and 100 parts by mass or less, preferably 90 parts by mass or more and 100 parts by mass or less.

Examples of the polyolefin resin constituting the transparent resin layer 3 include α-olefins (for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, etc., in addition to polypropylene, polyethylene, polybutene and the like. 1-Nonen, 1-Desen, 1-Undecene, 1-Dodecene, Tridecene, 1-Tetradecene, 1-Pentadecene, 1-Hexadecene, 1-Heptadesen, 1-Octadecene, 1-Nonadecene, 1-Eicosen, 3-Methyl- 1-Butene, 3-Methyl-1-Pentene, 3-Ethylene-1-Pentene, 4-Methyl-1-Pentene, 4-Methyl-1-hexene, 4,4-dimethyl-1-Pentene, 4-Ethylene- 1-Hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc.) are homopolymerized or copolymerized in two or more types. , Ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl methacrylate copolymer, ethylene / butyl methacrylate copolymer, ethylene / methyl acrylate copolymer, ethylene -Examples include those obtained by copolymerizing ethylene or α-olefin with other monomers, such as an ethyl acrylate copolymer and an ethylene / butyl acrylate copolymer. Further, when improving the surface strength of the decorative sheet 1, it is preferable to use highly crystalline polypropylene.
The thickness of the transparent resin layer 3 is preferably 20 μm or more and 200 μm or less. When the thickness of the transparent resin layer 3 is within this range, the strength of the decorative sheet 1 is improved, the printing workability when manufacturing the decorative sheet 1 is improved, and the manufacturing cost can be suppressed.

<Surface protective layer>
The surface protective layer 2 is provided on the outermost surface of the decorative sheet 1 and has a function of protecting the surface and adjusting the gloss. Examples of the material constituting the surface protective layer 2 include polyurethane resin, acrylic silicon resin, fluororesin, epoxy resin, vinyl resin, polyester resin, melamine resin, aminoalkyd resin, urea resin and the like. Can be mentioned. The form of the resin material is not particularly limited, such as water-based, emulsion, and solvent-based. As for the curing method, a one-component type, a two-component type, an ultraviolet curing method, or the like can be appropriately selected.

In particular, as the resin material that is the main component of the surface protective layer 2, a urethane-based resin using isocyanate is suitable from the viewpoints of workability, price, cohesive force of the resin itself, and the like. Examples of isocyanates include tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), diphenylmethane diisocyanate (MDI), lysine diisocyanate (LDI), isophorone diisocyanate (IPDI), and methylhexane diisocyanate (HTDI). , Methylcyclohexamethylene diisocyanate (HXDI), trimethylhexamethylene diisocyanate (TMDI) and the like can be appropriately selected. Among them, hexamethylene diisocyanate (HMDI) having a linear molecular structure is preferable as the isocyanate from the viewpoint of weather resistance. In addition to this, when improving the surface hardness, it is preferable to use a resin that is cured by active energy rays such as ultraviolet rays and electron beams. These resins can be used in combination with each other. For example, by using a hybrid type of a thermosetting type and a photocuring type, the surface hardness can be improved, the curing shrinkage can be suppressed, and the adhesion can be improved. Can be planned.
The thickness of the surface protective layer 2 is preferably 3 μm or more and 20 μm or less. When the thickness of the surface protective layer 2 is within this range, the surface of the decorative sheet 1 can be protected and sufficiently glossed, the printing workability at the time of manufacturing the decorative sheet 1 is improved, and the manufacturing cost is improved. Can be suppressed.

<Concealment layer>
The concealing layer 7 is formed for the purpose of maintaining concealment with respect to the base plate 9 in a decorative plate in which the surface of the decorative sheet 1 on the side of the primer layer 8 is attached to the base plate 9 such as a wood base material. To. The concealing layer 7 is formed by printing ink, for example, like the printing layer 5. As the pigment to be contained in the ink, it is preferable to use an opaque pigment, titanium oxide, iron oxide or the like. Further, in order to improve the concealing property of the pattern of the base plate 9 made of a wood base material or the like to which the decorative sheet 1 is attached in the concealing layer 7, metals such as gold, silver, copper and aluminum are added to the ink. It is also possible, and it is generally preferable to add flake-shaped aluminum. As described above, in the concealing layer 7, any of the base layers of the base material 6 (for example, the surface layer 6-1 or the second base material layer 6-2) is opaque and has a concealing property. In some cases, it can be omitted.
The thickness of the concealing layer 7 is preferably 2 μm or more and 20 μm or less. When the thickness of the concealing layer 7 is within this range, the concealing property with respect to the base plate 9 can be maintained, the printing workability at the time of manufacturing the decorative sheet 1 can be improved, and the manufacturing cost can be suppressed.

<Primer layer>
The primer layer 8 is provided in order to improve the adhesion between the decorative sheet 1 and the base plate 9 in the decorative plate in which the surface of the decorative sheet 1 on the primer layer 8 side is attached to the base plate 9.
As the primer layer 8, basically the same material (printing ink) as that of the printing layer 5 can be used. In particular, considering that the printing ink is wound in the form of a web because it is applied to the back surface of the decorative sheet 1, an inorganic filler such as silica, alumina, magnesia, titanium oxide, or barium sulfate is added to the printing ink. Is preferable. As a result, it is possible to avoid the occurrence of blocking when winding the decorative sheet 1 and to improve the adhesion with the adhesive.

When the base plate 9 is a wood base material, the primer layer 8 is, for example, an ester resin, a urethane resin, an acrylic resin, a polycarbonate resin, a vinyl chloride-vinyl acetate copolymer, a polyvinyl butyral resin, and the like. It is preferably formed of a resin material such as a nitrocellulose resin. These resin materials can be used alone or mixed to form an adhesive composition, and can be formed by using an appropriate coating means such as a roll coating method or a gravure printing method. In this case, it is preferable to use a urethane-acrylate resin as the resin material constituting the primer layer 8. That is, it is particularly preferable to form the resin composed of a copolymer of an acrylic resin and a urethane resin and an isocyanate.
The thickness of the primer layer 8 is preferably 0.1 μm or more and 20 μm or less. When the thickness of the primer layer 8 is within this range, the adhesion between the decorative sheet 1 and the base plate 9 is improved, and the printing workability when manufacturing the decorative sheet 1 is improved and manufactured. The cost can be suppressed.

The decorative sheet 1 using the base material 6 according to the present embodiment improves nonflammability and base material strength by using the base material 6 formed by stretching a resin film made of a thermoplastic resin to form a thin film. There is.
Further, in the decorative sheet 1 according to the present embodiment, the layers of the thermoplastic resin constituting the stretched film are multi-layered, and the melting point of the surface layer 6-1 is set to the base material layers 6-2 to other than the surface layer 6-1. By setting the temperature 20 ° C. or higher lower than the melting point of 6-n, the crystallinity on the surface of the substrate is reduced, and the wet affinity of the ink with respect to the substrate 6 (how much the ink soaks into the original film). It suppresses the deterioration and maintains the adhesion with the ink (printing layer). As a result, durability as a decorative sheet can be ensured without necessarily embossing.

Further, by lowering the melting point of the surface layer 6-1 to 20 ° C. or more lower than the melting point of the base layers 6-2 to 6-n other than the surface layer 6-1, the base material other than the surface layer 6-1 is used. It does not relax the orientation of layers 6-2 to 6-n. Therefore, by embossing the uneven structure on the decorative sheet base material 6, the adhesion between the decorative sheet base material 6 and the printing layer 5 can be further improved.
As described above, according to the present embodiment, it is possible to obtain the decorative sheet 1 having both the strength and durability of the base material.
Further, since the base material 6 can be thinned by stretching, it is possible to improve the nonflammability.

Hereinafter, the decorative sheet of the present invention will be specifically described with reference to Examples.
<Sample 1>
The decorative sheet of Sample 1 was formed by the steps shown below.
(Process for forming a resin sheet for a transparent resin layer)
First, a resin material is prepared by adding a hindered phenol-based antioxidant, a benzotriazole-based ultraviolet absorber, and a hindered amine-based light stabilizer to a homopolypropylene resin. Here, as the homopolypropylene resin, a material having a mesopentad fraction of 97.8%, an MFR (melt flow rate) of 15 g / 10 min (230 ° C.), and a molecular weight distribution MWD (Mw / Mn) of 2.3 is used. bottom. Further, 0.05% by mass (500PPM) of the hindered phenolic antioxidant (Irganox 1010: manufactured by BASF) was added to the homopolypropylene resin. The benzotriazole-based ultraviolet absorber (Tinubin 328: manufactured by BASF) was added in an amount of 0.2% by mass (2000PPM) with respect to the homopolypropylene resin. The hindered amine-based light stabilizer (Kimasorb 944: manufactured by BASF) was added in an amount of 0.2% by mass (2000PPM) based on the homopolypropylene resin. Such a resin material was extruded using a melt extruder to form a transparent resin sheet made of polypropylene having a thickness of 80 μm to be used as a transparent resin layer.
Subsequently, both sides of the obtained transparent resin sheet were subjected to corona treatment to set the wetting tension on the surface of the transparent resin sheet to 40 dyn / cm or more.

(Base material forming process)
It was formed by forming and stretching a base material in which two layers of a surface layer and a second base material layer were laminated by an extrusion method. That is, the base material for the decorative sheet was composed of two thermoplastic resin layers.
A layer serving as a precursor of the surface layer of the first layer was formed to a thickness of 60 μm using a resin material A (low density polyethylene, melting point 120 ° C.) to which an inorganic pigment was added. Subsequently, a layer to be a precursor of the second base material layer of the second layer is added to a resin material E (homopolypropylene, melting point 160) to which an inorganic pigment is added on the layer to be the precursor of the surface layer of the first layer. It was formed to a thickness of 60 μm using ° C.). As a result, a laminated resin precursor having a total thickness of 120 μm was formed.
Subsequently, the laminated resin precursor was stretched four times by a uniaxial stretching method to form a substrate having a thickness of 30 μm (the film thickness of the surface layer was 15 μm and the film thickness of the second substrate layer was 15 μm).

(Embossing process on the base material layer)
In the embossing process, the laminated stretched sheet constituting the base material is passed between the embossed roll having a surface roughness shape and the mirror surface roll, and a pressure of 20 MPa is applied to transfer the surface structure of the embossed roll to the surface layer. I went there. The temperature of the embossed roll was 110 ° C.

(Printing layer and primer layer forming process)
A print layer was formed by performing pattern printing on the surface layer of the base material by a gravure printing method. The printing layer is a two-component urethane ink (V180; manufactured by Toyo Ink Mfg. Co., Ltd.) containing 0.5% by mass of a hindered amine-based light stabilizer (Kimasorb 944; manufactured by BASF) with respect to the binder resin content of the ink. It was formed using the added ink.
In addition, a primer layer was formed on the back surface of the second base material layer of the base material. The primer layer was formed by printing a two-component urethane ink similar to the printing layer by a gravure printing method.

(Transparent resin layer forming process)
Subsequently, a dry laminating adhesive (Takelac A540; manufactured by Mitsui Chemicals, Inc .; coating amount 2 g / m ² ) was applied as an adhesive layer to the front surface (printing layer forming surface) of the base material. After that, a transparent resin sheet was formed by laminating a transparent resin sheet on the front surface of the base material via an adhesive layer by a dry laminating method. The surface of the transparent resin layer was embossed.

(Surface protective layer forming process)
A two-component curable urethane top coat (W184; manufactured by DIC Graphics Co., Ltd.) was applied to the surface of the embossed transparent resin layer at a coating thickness of 6 g / m ² and dried to form a surface protective layer. ..
As a result, a decorative sheet having a total thickness of 120 μm was obtained.

<Sample 2>
The surface layer was formed of the resin material B (random polypropylene, melting point 135 ° C.), and a decorative sheet was formed in the same manner as in Sample 1 except that the embossing roll temperature was 125 ° C.
<Sample 3>
The surface layer was formed of resin material C (mixed resin of 100 parts by mass of random polypropylene and 100 parts by mass of low crystalline polypropylene (mesopentide fraction 30%), melting point 100 ° C.) except that the embossing roll temperature was 90 ° C. , A decorative sheet was formed in the same manner as in Sample 1.

<Sample 4>
The surface layer was formed of a resin material D (mixed resin of 100 parts by mass of random polypropylene and 20 parts by mass of low crystalline polypropylene (mesopentad fraction 30%), melting point 105 ° C.) except that the embossing roll temperature was 95 ° C. , A decorative sheet was formed in the same manner as in Sample 1.
<Sample 5>
The surface layer and the second base material layer were formed without containing a pigment, and a decorative sheet was formed in the same manner as in Sample 1 except that the embossing roll temperature was set to 110 ° C.

<Sample 6>
A decorative sheet was formed in the same manner as in Sample 1 except that the surface layer was used as the resin material E, the second base material layer was formed as the resin material A, and the embossing roll temperature was set to 150 ° C.
<Sample 7>
The decorative sheet was formed in the same manner as in Sample 1 except that the surface layer was formed as the resin material E, the second base material layer was formed as the resin material F (homopolypropylene, melting point 165 ° C.), and the embossed roll temperature was set to 150 ° C. Formed.

<Sample 8>
A decorative sheet was formed in the same manner as in Sample 1, except that a substrate having no second substrate layer was used and the thickness after stretching was 30 μm.
<Sample 9>
The surface layer is formed using resin material B (random polypropylene, melting point 135 ° C.) so that the thickness after stretching is 30 μm, and the embossing roll temperature is set using a base material without a second base material layer. A decorative sheet was formed in the same manner as in Sample 1 except that the temperature was 125 ° C.

<Sample 10>
A decorative sheet was formed in the same manner as in Sample 1 except that the thickness of the second base material layer after stretching was 30 μm, a base material having no surface layer was used, and the embossing roll temperature was 150 ° C.
<Sample 11>
The second base material layer was formed to a thickness of 30 μm without stretching, a base material having no surface layer was used, and the decorative sheet was prepared in the same manner as in Sample 1 except that the embossing roll temperature was set to 150 ° C. Formed.

<Sample 12>
The second base material layer was formed to a thickness of 60 μm without stretching, a base material having no surface layer was used, and the decorative sheet was prepared in the same manner as in Sample 1 except that the embossing roll temperature was set to 150 ° C. Formed.
<Sample 13>
A decorative sheet was formed in the same manner as in Sample 1 except that the second base material layer was formed to a thickness of 60 μm without stretching, a base material having no surface layer was used, and no embossing was performed. bottom.

<Sample 14>
A decorative sheet was formed in the same manner as in Sample 1 except that the thickness of the second base material layer after stretching was 30 μm, a base material having no surface layer was used, and embossing was not performed.
<Sample 15>
A decorative sheet was formed in the same manner as in Sample 1 except that embossing was not performed.

<Performance evaluation of decorative sheet>
The performance of each sample of the decorative sheet was evaluated.
[Tension modulus]
The decorative sheet of each sample was pulled at 50 mm / min by a Tensilon universal material tester, and the elastic modulus was measured.
The evaluation of elastic modulus is as follows.
◯: Good (elastic modulus of 500 MPa or more)
X: Defective (elastic modulus less than 500 MPa)

[Non-flammable test]
Using the decorative sheet of each sample, a heat generation test was carried out by a cone calorie meter tester compliant with ISO5660-1. Nonflammability was determined by whether or not the provisions of Article 108-2, Items 1 and 2 of the Building Standards Act Enforcement Ordinance were satisfied.
The evaluation of nonflammability is as follows.
○: Good (within standard)
×: Defective (non-standard)

[Interlayer adhesion test]
The interlayer adhesion test is a test for evaluating the adhesion between the transparent resin layer and the base material. The interlayer adhesion test was carried out according to JIS K 6854-2 using the decorative sheet of each sample.
The evaluation of the interlayer adhesion is as follows.
◎: Very good (within standard)
○: Good (within standard)
Δ: Adhesion that can withstand practical use (within standard)
×: Defective (non-standard)
[Transparency test]
The transparency test is a test for evaluating the design of a decorative sheet. In the transparency test, the transmittance of the decorative sheet of each sample was measured and evaluated by a spectrophotometer.
The evaluation of the light transmittance is as follows.
○: Good concealment (within standard)
×: Concealment is poor (non-standard)
Table 1 below shows the results of each evaluation.

As can be seen from Table 1, Samples 1 to 5 have a surface layer and a second base material layer, and the melting point of the resin constituting the surface layer is 20 ° C. or more lower than the melting point of the second base material layer. The decorative sheet of No. 1 was excellent in elastic modulus, nonflammability, and interlayer adhesion.
Further, the decorative sheets of Samples 1 to 4 containing the pigment in the surface layer and the second base material layer are lighter than the decorative sheets of Sample 5 containing no pigment in the surface layer and the second base material layer. The transmittance was low and the concealment was excellent.

On the other hand, the decorative sheet of Sample 6, in which the melting point of the surface layer of the base material was higher than the melting point of the second base material layer, did not have a sufficient elastic modulus. Similarly, the elastic modulus of the decorative sheet of Sample 7, in which the difference in melting point between the surface layer of the base material and the second base material layer was less than 20 ° C., was not sufficient. The elastic modulus was also insufficient for the decorative sheets from Sample 8 to Sample 11, which had only the surface layer or the second base material. From this result, in order to improve the strength of the decorative sheet, the surface layer and the second base material layer are provided, and the melting point of the resin constituting the surface layer is 20 as compared with the melting point of the second base material layer. It turned out that it needs to be lower than ℃.
Further, in a decorative sheet having only a second base material layer having a thickness of 30 μm and a melting point of 160 ° C. without providing a surface layer as in sample 14, when the base material is stretched, embossing is performed. If not, the interlayer adhesion was reduced.

On the other hand, a decorative sheet such as sample 13 in which the base material is not stretched and does not have an embossed structure has sufficient interlayer adhesion, but as can be seen from sample 15, even if stretched, it can be stretched. If the surface layer and the second base material layer are provided and the melting point of the resin constituting the surface layer is set to be 20 ° C. or more lower than the melting point of the second base material layer, even if embossing is not performed. It was found that the interlayer adhesion sufficient for practical use is secured. Further, by embossing the decorative sheet as in the case of sample 1, it is possible to improve the interlayer adhesion of the decorative sheet.
Further, the decorative sheet of Sample 11 in which the base material did not have a surface layer and the second base material layer was not stretched had particularly good interlayer adhesion because it was not stretched. However, the decorative sheet of Sample 11 having a film thickness of the second base material layer of 30 μm did not have a sufficient elastic modulus. Further, the decorative sheets of Samples 12 and 13 having a film thickness of the second base material layer of 60 μm had a sufficient elastic modulus because the film thickness of the second base material layer was thicker than that of the decorative sheet of Sample 11. However, the nonflammability decreased. From this result, it was found that it is difficult to achieve both the strength and nonflammability of the decorative sheet when stretching (thinning) is not performed in order to compensate for the decrease in interlayer adhesion due to stretching.

From the above results, a decorative sheet having a surface layer and a second base material layer and having a melting point of the resin constituting the surface layer lower than the melting point of the second base material layer by 20 ° C. or more has an elastic modulus. It was excellent in nonflammability and interlayer adhesion. That is, if the decorative sheet has a surface layer and a second base material layer and the melting point of the resin constituting the surface layer is 20 ° C. or more lower than the melting point of the second base material layer, the elastic modulus (base). It can solve both the problems of material strength) and interlayer adhesion (durability). Further, it was found that the surface layer and the second base material layer contained an inorganic pigment, so that further low light transmission (high concealing property) could be obtained.
Although the present invention has been described above with reference to each embodiment, the scope of the present invention is not limited to the illustrated and described exemplary embodiments, and the present invention has an effect equivalent to that of the object of the present invention. Also includes all embodiments. Furthermore, the scope of the present invention is not limited to the combination of the features of the invention defined by the claims, but may be defined by any desired combination of specific features among all disclosed features.

1 Decorative sheet 2 Surface protective layer 3 Transparent resin layer 4 Adhesive layer 5 Printing layer 6 Base material (base material for decorative sheet)
6-1 Surface layer (base layer)
6-2 to 6-n Base layer other than surface layer 7 Concealment layer 8 Primer layer 9 Base plate

Claims (10)

A uniaxial or biaxial laminated stretched film,
When a first layer having a plurality of thermoplastic resin layers and located on the outermost surface of the plurality of thermoplastic resin layers is defined as a surface layer, the melting point of the resin of the surface layer is the surface. 20 ° C or more lower than the melting point of the resin of the thermoplastic resin layer other than the layer,
The surface roughness on the surface layer is in the range where the maximum valley depth Rv is 5 μm or more and 10 μm or less .
The surface layer further contains polypropylene as a soft material having a mesopentad fraction in the range of 30% or more and less than 50%.
A laminated stretched film characterized in that the thermoplastic resin is a polyolefin resin . The laminated stretch according to claim 1, wherein the melting point of the resin of the surface layer is lower in the range of 20 ° C. or higher and 70 ° C. or lower as compared with the melting point of the resin of the thermoplastic resin layer other than the surface layer. the film. The laminated stretched film according to claim 1 or 2, wherein the thermoplastic resin is a polypropylene-based resin. The surface layer contains polypropylene having a mesopentad content in the range of 30% or more and less than 50% in an amount of 5 parts by mass or more with respect to 100 parts by mass of the resin having the highest content among the resins constituting the surface layer. The laminated stretched film according to any one of claims 1 to 3, wherein the film is contained within a range of less than 30 parts by mass. A uniaxial or biaxial laminated stretched film,
When a first layer having a plurality of thermoplastic resin layers and located on the outermost surface of the plurality of thermoplastic resin layers is defined as a surface layer, the melting point of the resin of the surface layer is the surface. 20 ° C or more lower than the melting point of the resin of the thermoplastic resin layer other than the layer,
The surface layer further contains, as a soft material, a polyolefin resin having a mesopentad fraction in the range of 30% or more and less than 50%.
A laminated stretched film characterized in that the thermoplastic resin is a polyolefin resin . The laminated stretched film according to claim 5 , wherein the soft material is polypropylene having a mesopentad fraction in the range of 30% or more and less than 50%. A base material for a decorative sheet, comprising the laminated stretched film according to any one of claims 1 to 6 . Satisfies the requirements described in Article 108-2, No. 1 and No. 2 of the Building Standards Act Enforcement Ordinance in the heat generation test by the cone calorie meter tester conforming to ISO5660-1 in the state of being bonded to the nonflammable substrate. The base material for a decorative sheet according to claim 7 , which is a non-combustible material. The base material for a decorative sheet according to claim 7 or 8 , and a one-layer or a plurality of transparent resin layers containing a polyolefin resin formed on the surface of the base material for a decorative sheet on the surface layer side. A decorative sheet characterized by being prepared. A decorative board according to claim 9 , wherein the decorative sheet is provided on a wooden base material.

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