WO2018117268A1

WO2018117268A1 - Multilayer stretched film, substrate for decorative sheets, decorative sheet and decorative panel

Info

Publication number: WO2018117268A1
Application number: PCT/JP2017/046262
Authority: WO
Inventors: 真志服部
Original assignee: 凸版印刷株式会社
Priority date: 2016-12-22
Filing date: 2017-12-22
Publication date: 2018-06-28
Also published as: JP7052731B2; JPWO2018117268A1

Abstract

Provided are: a multilayer stretched film which achieves a good balance between substrate strength and durability; a substrate for decorative sheets, which is provided with the multilayer stretched film; a decorative sheet which is provided with this substrate for decorative sheets; and a decorative panel which is provided with this decorative sheet. A substrate (6) for decorative sheets according to an embodiment of the present invention is provided with a multilayer stretched film having a plurality of thermoplastic resin layers, and the melting point of a surface layer (6-1) is lower than the melting point of the resin of the substrate layers (6-2 to 6-n) other than the surface layer (6-1) by 20°C or more. A decorative sheet (1) is provided with the substrate (6) for decorative sheets and one or more transparent resin layers (3) which are formed on the surface layer (6-1)-side surface of the substrate (6) for decorative sheets and contain a polyolefin resin. The surface layer (6-1) and/or the substrate layers (6-2 to 6-n) other than the surface layer (6-1) contain a polyolefin resin. The surface layer (6-1) contains, as the polyolefin resin, a polypropylene that has a mesopentad fraction of 30% or more but less than 50%.

Description

Laminated stretched film, base material for decorative sheet, decorative sheet and decorative plate

The present invention relates to a laminated stretched film, a decorative sheet substrate, a decorative sheet, and a decorative plate.

In the decorative sheet used for the surface of building interior materials and fittings, especially for the decorative sheet used for public use, the non-combustible material described in the Building Standard Law Enforcement Ordinance Article 108-2 No. 1 and No. 2 To meet technical standards. Conventionally, as a decorative sheet satisfying the technical standard of such a noncombustible material, one using a soft polyvinyl chloride resin has been used. However, a decorative sheet using a soft polyvinyl chloride resin has problems such as generation of toxic gas during incineration after disposal.
For this reason, a decorative sheet using a polyolefin resin instead of the polyvinyl chloride resin has been proposed. However, when polyolefin resin is used, the generation of toxic gases during combustion is suppressed, but because polyolefin resin has excellent flammability, technical standards for nonflammable materials It was difficult to satisfy.

As a decorative sheet using a polyolefin-based resin that satisfies the technical standards for non-combustible materials described in the above-mentioned laws and regulations, there are decorative sheets described in

Patent Documents

1 and 2, for example.

Patent Documents

1 and 2 disclose a structure using a polyolefin resin layer in which an inorganic filler such as calcium carbonate is blended.

JP 2013-010931 A JP 2011-122293 A

Here, as a method for obtaining a decorative sheet made of a polyolefin-based resin that satisfies the technical standards for non-combustible materials as described above, for example, there is a method of thinning a base material of the decorative sheet. In general, in order to impart designability to the decorative sheet, a printing layer is provided on the substrate surface side. At this time, when the substrate is put into the printing machine, the substrate is required to have sufficient mechanical strength in order to suppress the occurrence of the displacement of the printing position.
In order to cope with the above, if a stretched film subjected to uniaxial stretching or biaxial stretching is used as a decorative sheet base material, the decorative sheet base material becomes thin and simultaneously increases the nonflammability of the decorative sheet. It is possible to increase the mechanical strength of the decorative sheet base material and the decorative sheet.

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

Coexistence of such improvement of peel strength and strength improvement by stretching is a problem in obtaining a decorative sheet having both base material strength and durability.
The present invention has been made paying attention to the above points, and is a laminated stretched film having both base material strength and durability, a decorative sheet base material provided with the laminated stretched film, and a decorative sheet base material. It aims at providing the decorative sheet provided with, and the decorative board provided with the decorative sheet.

In order to solve the problems, a laminated stretched film according to one embodiment of the present invention is a uniaxial or biaxial laminated stretched film having a plurality of thermoplastic resin layers, and the plurality of thermoplastic resins. 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 compared to the melting point of the resin of the thermoplastic resin layer other than the surface layer. Low.
Moreover, the decorative sheet according to one embodiment of the present invention is a single-layer or multiple-layer transparent resin layer including the above-described decorative sheet base material and a polyolefin-based resin formed on the surface layer side surface of the decorative sheet base material. And comprising.

According to one aspect of the present invention, a laminated stretched film having both substrate strength and durability, a base for a decorative sheet provided with the laminated stretched film, a decorative sheet provided with the base for decorative sheet, and the decorative sheet Can be obtained.
That is, since it is a stretched film, it is possible to simultaneously increase the thickness and mechanical strength of the substrate.
At this time, if the film is stretched, the crystallization of the film surface as the base material proceeds, and the wet affinity of the ink to the base material (how far the ink penetrates into the original fabric) is reduced, so Adhesion with the material may be reduced. On the other hand, according to one aspect of the present invention, the thermoplastic resin layer 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. 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.
Moreover, since a base material can be thinned by extending | stretching, it also becomes possible to raise 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 schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Further, the embodiment described below exemplifies a configuration for embodying the technical idea of the present invention, and the technical idea of the present invention is that the material, shape, structure, etc. of the component parts are as follows. It is not something specific. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

FIG. 1 is a cross-sectional view illustrating a configuration of a 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 including a plurality of thermoplastic resin layers, and on one surface (front 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 substrate 6.
Here, the base material 6 includes 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. 6-2 to at least one of the nth base material layers 6-n. That is, the substrate 6 includes a surface layer 6-1 and n layers from the second substrate layer 6-2 to the n-th substrate layer 6-n (n is an arbitrary positive integer of 2 or more). The base material layer is formed.

When the substrate 6 is composed of two layers of the surface layer 6-1 and the second substrate layer 6-2, the back surface of the second substrate layer 6-2 becomes the other surface of the substrate 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 this embodiment, since an inorganic pigment is mixed in the base material 6 as will be described later, there is no problem in design even if the masking layer 7 is omitted. When suppressing the pigment mixed with the base material 6 to a small amount, it is preferable to provide a concealing layer 7 as necessary.
The thickness of the decorative sheet 1 is preferably in the range of 49 μm to 360 μm, for example. When the thickness of the decorative sheet 1 is within this range, the printing workability when manufacturing the decorative sheet 1 is improved and the manufacturing cost can be suppressed.
Such a decorative sheet 1 comprises a decorative board by affixing the surface by the side of the primer layer 8 to the base material board 9 which consists of a wooden base material etc., for example.
Hereinafter, each part of the decorative sheet 1 will be described in detail.

<Base material>
The substrate 6 is made of a laminated stretched film that has been thinned by uniaxial stretching or biaxial stretching from the viewpoint of nonflammability. The thickness of the substrate 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 and the mechanical properties (strength) of the decorative sheet 1 can be achieved. Moreover, since the nonflammability improves further when the thickness of the base material 6 is the range of 20 micrometers or more and 40 micrometers or less, it is more preferable.

The non-flammability of the base material 6 is the heat generated by a cone calorimeter tester compliant with ISO5660-1 in a state where the substrate to which the decorative sheet is attached is bonded to a non-flammable base material (not shown) made of a metal plate or an inorganic material. In the property test, it is preferable to have incombustibility sufficient to satisfy the requirements described in Article 108-2, Item 1 and Item 2 of the Building Standard Law Enforcement Ordinance.
Each layer which comprises the base material 6 is formed with the resin material, and contains the thermoplastic resin as a main component of the resin material. The main component refers to, for example, a resin material that is contained in an amount of 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, with 100 parts by mass of the resin material constituting the layer.

(Melting point of base material 6)
The surface layer 6-1 of the substrate 6 contains a thermoplastic resin whose melting point is at least 20 ° C. lower than the other substrate layers 6-2 to 6-n. By setting the difference between the melting points of the resins to be 20 ° C. or lower, when embossing is performed on the base material, the temperature of the embossing on the surface layer is reduced in the base material layers 6-2 to 6-n other than the surface layer. The orientation can be maintained to some extent. For this reason, it is possible to improve the interlayer adhesion between the surface layer 6-1 and the transparent resin layer 3 while maintaining the effect of improving the strength of the substrate by stretching.

Even when the surface layer 6-1 is not embossed, the crystallinity of the surface layer 6-1 can be 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 the crystallization proceeds. For example, a high crystalline polypropylene has a melting point of about 160 ° C., and crystallization is likely to proceed. However, low-density polyethylene has a melting point of 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 substrate layer 6-2 to the n-th substrate layer 6-n and the melting point of the thermoplastic resin contained in the surface layer 6-1 is 20 ° C. When the surface layer 6-1 is embossed, the ink adhesion between the substrate 6 and the printing layer 5 is improved when the surface layer 6-1 is embossed, but the stretched and oriented layers of the substrate layers 6-2 to 6-n The effect of relaxing the orientation is increased, and the effect of improving the strength of the substrate 6 by stretching is reduced.
Here, in order for the surface layer 6-1 to be a combination of thermoplastic resins whose melting point is at least 20 ° C. lower than the other base material layers 6-2 to 6-n, for example, the surface layer 6-1 is This is realized by forming with low density polyethylene and forming the other substrate layers 6-2 to 6-n with highly crystalline polypropylene.

(Resin materials and soft materials)
At least one layer constituting the substrate 6, that is, the surface layer 6-1 and another substrate layer different from the surface layer 6-1 (second substrate layer 6-2 to n-th substrate layer 6-n). At least one layer preferably contains a polyolefin resin. Examples of the polyolefin resin include polyethylene, polypropylene, polybutene and the like, as well as 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, 4-ethyl-1-hexene, 3-ethyl -1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene Or the like, or ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl methacrylate copolymer, ethylene / vinyl methacrylate copolymer, Copolymerized ethylene or α-olefin with other monomers such as butyl methacrylate copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / butyl acrylate copolymer Is mentioned. 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. Moreover, when aiming at the improvement of the tensile elasticity modulus of the base material 6, it is preferable to use a highly crystalline polypropylene. In this embodiment, a resin group including polypropylene and derivatives thereof 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 embossability. For the surface layer 6-1, for example, a polyolefin resin having a mesopentad fraction of 30% or more and less than 50% is preferably used as a soft material. Specifically, it is particularly preferable to use, as the soft material, for example, a polypropylene resin having a mesopentad fraction in the range of 30% to less than 50%, particularly a low crystalline polypropylene resin.
When the surface layer 6-1 includes a soft material, the surface layer 6-1 includes 5 parts by mass or more and 30 parts by mass of the soft material with respect to 100 parts by mass of the main component resin (base resin) constituting the surface layer 6-1. Preferably, it is formed of a mixed resin mixed with less than a part. 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 hardly appears. 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 sticking of the surface layer 6-1 becomes a problem due to the heat treatment at the time of stretching the base material 6. There is.
Further, from the viewpoint of 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 such a viewpoint, 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 substrate)
The adhesion between the surface layer 6-1 of the decorative sheet substrate 6 and the printed layer 5 formed on the surface layer 6-1 of the decorative sheet substrate 6 depends on the roughness of the surface of the substrate 6. improves. However, since the surface roughness of the substrate 6 is reduced by performing uniaxial or biaxial stretching, the stretched substrate is more closely attached to the printed layer than the non-stretched substrate. The nature will decline. Therefore, from the viewpoint of improving the adhesion between the base material 6 and the printed layer 5, it is desirable to provide an appropriate surface roughness for the base material 6 after stretching. A preferable surface roughness index on the substrate 6 is that the maximum valley depth Rv is in the range of 5 μm to 10 μm. When Rv is less than 5 μm, the anchor effect for bonding 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 influence on the gloss value of the printed layer is large, and the design properties required of the decorative sheet change, which is not preferable.

(About embossing method)
Embossing is performed by pressure-bonding an embossing roll to the base material 6, and the roughness according 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 needs to be equal to or higher than the temperature at which the substrate 6 is sufficiently thermally deformed. In particular, in the present application, although the surface layer 6-1 of the substrate 6 is deformed, the surface layer 6- It is desirable that the temperature be lower than the temperature at which the base material layers 6-2 to 6-n other than 1 are deformed. The embossing roll temperature appropriate for the resin is not uniquely determined because it is affected by the pressure at the time of pressure bonding. However, under a certain pressure, the melting point of the resin constituting each layer of the substrate 6 Therefore, if the design is such that the melting point of the surface layer 6-1 of the substrate 6 is 20 ° C. lower than the melting points of the other layers 6-2 to 6-n as in the present application, the surface layer of the substrate 6 At the temperature at which the embossing roll surface structure starts to be transferred to 6-1, the base material layers 6-2 to 6-n other than the surface layer 6-1 are not deformed or the deformation amount is kept small.

(Inorganic pigment)
At least one layer constituting the substrate 6, that is, a surface layer 6-1 and a substrate layer different from the surface layer 6-1 (second substrate layer 6-2 to n-th substrate layer 6-n) At least one layer preferably contains an inorganic pigment. By containing an 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 material layers 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 incombustibility due to the addition of the inorganic pigment is exhibited, and the embrittlement of the base material 6 due to the excessive addition amount of the inorganic pigment is also suppressed. It is because it can do.

Although it does not specifically limit as an inorganic pigment contained in the at least 1 layer which comprises the base material 6, For example, a natural inorganic pigment and a synthetic inorganic pigment are mentioned.
Examples of natural inorganic pigments include earth-based pigments, calcined soils, and mineral pigments. Examples of the synthetic inorganic pigment include oxide pigments, hydroxide pigments, sulfide pigments, silicate pigments, phosphate pigments, carbonate pigments, metal powder pigments, and carbon pigments. Moreover, you may use the mixed pigment which mixed the 1 type (s) or 2 or more types from the natural inorganic pigment and the synthetic inorganic pigment.
In addition, it is not preferable to use an organic pigment as the pigment. This is because the incombustibility of the substrate 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 concealability required from the viewpoint of the design properties of the decorative sheet 1. When the light transmittance exceeds 40%, sufficient concealing property for obtaining the design of the decorative sheet 1 cannot be obtained. If sufficient concealability is not obtained, for example, in the decorative board in which the surface on the primer layer 8 side of the decorative sheet 1 is affixed to the base board 9 made of a wooden base material, the base material such as a wooden base material 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 through the decorative sheet 1. When visible, the pattern of the printed layer 5 and the pattern of the base plate 9 such as a wooden base material may overlap and be visually recognized.

<Print layer>
The printed layer 5 is a layer on which a pattern is formed in order to impart design properties. The printing layer 5 can be provided on the surface layer 6-1 of the decorative sheet base 6 using a known printing technique. When the substrate 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 for example, a gravure printing method can be used in consideration of productivity and picture quality.
An arbitrary pattern may be adopted as the design pattern in consideration of the design properties according to the place of use such as flooring or wall material. For example, when obtaining the decorative sheet 1 having a wooden pattern, various types of grain patterns are often used for the pattern, and a cork pattern may be used in addition to the grain pattern. In addition, when 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 pattern patterns of natural materials, an artificial pattern such as an artificial pattern or a geometric pattern using them as a motif is used as the pattern pattern of the printing layer 5.

The printing ink used for forming the printing layer 5 is not particularly limited, but an ink corresponding to the printing method is appropriately selected. In particular, it is preferable to select a printing ink in consideration of adhesion to the substrate 6 and printability, weather resistance of the decorative sheet 1, and the like.
To the printing ink, a colorant such as a pigment or a dye, an extender pigment, a solvent, and a binder, which are contained in a normal ink, are appropriately added. Examples of the pigment include pearl pigments such as condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, and mica. The binder may be any of aqueous, solvent-based, and emulsion types, and the curing method is particularly limited, such as 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. Not what you want. Among them, the most common method is a two-component type, which uses a urethane-based main agent and a curing agent made of isocyanate. In addition, the design may be applied by vapor deposition or sputtering of various metals.
The thickness of the printing 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, the printing can be clarified, the printing workability when the decorative sheet 1 is manufactured can be improved, and the manufacturing cost can be suppressed.

<Adhesive layer>
The adhesive layer 4 is provided for the purpose of strengthening the adhesion between the substrate 6 and the printed layer 5 and the transparent resin layer 3. By virtue of the strong adhesion between the substrate 6 and the printed layer 5 and the transparent resin layer 3, the decorative sheet 1 can be given bending workability that follows a curved surface or a right angle 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 urethane-based material obtained by a reaction with a polyol using an isocyanate as a two-component curing type because of its cohesive strength. Note that the adhesive layer 4 may be omitted when the adhesive strength between the transparent resin layer 3 and the printed layer 5 is sufficiently obtained.

An arbitrary method can be selected as a method for bonding the base material 6 and the printed layer 5 through the adhesive layer 4 and the transparent resin layer 3. For example, a lamination method such as heat lamination, extrusion lamination, dry lamination, or the like can be used. 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 during the production of the decorative sheet 1 is improved, And manufacturing cost can be controlled.

<Transparent resin layer>
The transparent resin layer 3 is made of, for example, a transparent resin sheet, and is bonded to the base material 6 and the printing layer 5 with an adhesive layer 4. In the decorative sheet 1 shown in FIG. 1, the case where the transparent resin layer 3 is a single layer is illustrated, but a plurality of transparent resin layers 3 may be laminated. The transparent resin layer 3 of the present embodiment is preferably configured with a polyolefin resin as a main component. The main component means, for example, a resin material contained in 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, with 100 parts by mass of the resin material constituting the substrate 6.

Examples of polyolefin resins constituting the transparent resin layer 3 include α-olefins (eg, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, in addition to polypropylene, polyethylene, polybutene, and the like. 1-nonene, 1-decene, 1-undecene, 1-dodecene, tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl- 1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl- 1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl 1-tetradecene, etc.) or a copolymer of two or more types, ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl methacrylate copolymer Polymers, ethylene / butyl methacrylate copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / butyl acrylate copolymer, etc. Copolymerized one is mentioned. Moreover, 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 in 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 gloss. Examples of the material constituting the surface protective layer 2 include polyurethane resins, acrylic silicon resins, fluorine resins, epoxy resins, vinyl resins, polyester resins, melamine resins, aminoalkyd resins, urea resins, and the like. Is mentioned. The form of the resin material is not particularly limited, such as aqueous, emulsion, solvent type. The curing method can be appropriately selected from a one-component type, a two-component type, an ultraviolet curing method, and the like.

In particular, as a resin material that is a main component of the surface protective layer 2, urethane resins using isocyanate are suitable from the viewpoints of workability, cost, cohesive strength of the resin itself, and the like. Examples of the isocyanate include tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), diphenylmethane diisocyanate (MDI), lysine diisocyanate (LDI), isophorone diisocyanate (IPDI), methylhexane diisocyanate (HTDI). , Methylcyclohexanone diisocyanate (HXDI), trimethylhexamethylene diisocyanate (TMDI), and the like. Among these, from the viewpoint of weather resistance, hexamethylene diisocyanate (HMDI) having a linear molecular structure is suitable as the isocyanate. In addition to this, in order to improve the surface hardness, it is preferable to use a resin curable with 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 photocurable type, it is possible to improve surface hardness, suppress curing shrinkage, and improve adhesion. You can plan.
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, it is possible to protect the surface of the decorative sheet 1 and to provide sufficient gloss, to improve the printing workability when manufacturing the decorative sheet 1, and to reduce the manufacturing cost. 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 the decorative plate in which the surface on the primer layer 8 side of the decorative sheet 1 is attached to the base plate 9 such as a wood base. The The concealing layer 7 is formed, for example, by ink printing in the same manner as the printing layer 5. As the pigment to be included in the ink, it is preferable to use an opaque pigment, titanium oxide, iron oxide or the like. Moreover, in order to improve the concealability of the pattern of the base material board 9 which consists of the wooden base material etc. in which the decorative sheet 1 in the concealment layer 7 is affixed, metals, such as gold | metal | money, silver, copper, aluminum, are added to ink. In general, it is preferable to add flaky aluminum. Note that, as described above, the concealing layer 7 has any concealing property because any one of the base layers 6 (for example, the surface layer 6-1 or the second base layer 6-2) is opaque. In some cases, it can be omitted.
The thickness of the masking layer 7 is preferably 2 μm or more and 20 μm or less. When the thickness of the concealment layer 7 is within this range, the concealability with respect to the base plate 9 can be maintained, the printing workability during the production of the decorative sheet 1 can be improved, and the production cost can be suppressed.

<Primer layer>
The primer layer 8 is provided to improve the adhesion between the decorative sheet 1 and the base plate 9 in the decorative plate in which the surface on the primer layer 8 side of the decorative sheet 1 is attached to the base plate 9.
The primer layer 8 can basically use the same material (printing ink) as the printing layer 5. Among these, in consideration of performing winding in a web shape for being applied to the back surface of the decorative sheet 1, an inorganic filler such as silica, alumina, magnesia, titanium oxide, barium sulfate or the like is added to the printing ink. It is preferable. Thereby, generation | occurrence | production of the blocking at the time of winding up the decorative sheet 1 can be avoided, and adhesion | attachment with an adhesive agent can be improved.

When the base plate 9 is a wood base, 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, 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, which can be formed using an appropriate application 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 made 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 the decorative sheet 1 is manufactured is improved and manufactured. Cost can be suppressed.

The decorative sheet 1 using the base material 6 according to the present embodiment improves the nonflammability and the base material strength by using the base material 6 formed by stretching and thinning a resin film made of a thermoplastic resin. Yes.
In addition, the decorative sheet 1 according to the present embodiment has a multilayer of thermoplastic resin layers constituting the stretched film, and the melting point of the surface layer 6-1 is changed to the base material layers 6-2 to 6-2 other than the surface layer 6-1. By setting the melting point of the substrate 6-n lower than the melting point of 6-n, the degree of crystallization on the substrate surface is reduced, and the wet affinity of the ink with respect to the substrate 6 (how far the ink penetrates the original fabric) Suppression is suppressed and adhesion with ink (printing layer) is maintained. As a result, durability as a decorative sheet can be ensured without necessarily embossing.

Further, by making the melting point of the surface layer 6-1 lower by 20 ° C. or more than the melting points of the substrate layers 6-2 to 6-n other than the surface layer 6-1, the substrate other than the surface layer 6-1. The orientation of the layers 6-2 to 6-n is not relaxed. For this reason, the adhesiveness of the base material 6 for decorative sheets and the printing layer 5 can further be improved by providing an uneven structure on the base material 6 for decorative sheets by embossing.
Thus, according to the present embodiment, it is possible to obtain the decorative sheet 1 having both the base material strength and the durability.
Furthermore, since the base material 6 can be thinned by stretching, nonflammability can be increased.

Hereinafter, the decorative sheet of the present invention will be specifically described with reference to examples.
<Sample 1>
A decorative sheet of Sample 1 was formed by the following steps.
(Process for forming resin sheet for transparent resin layer)
First, a resin material prepared by adding a hindered phenol-based antioxidant, a benzotriazole-based ultraviolet absorber, and a hindered amine-based light stabilizer to a homopolypropylene resin is prepared. 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. did. Further, 0.05% by mass (500 PPM) of a hindered phenol-based antioxidant (Irganox 1010: manufactured by BASF) was added to the homopolypropylene resin. A benzotriazole ultraviolet absorber (Tinuvin 328: manufactured by BASF) was added in an amount of 0.2% by mass (2000 PPM) to the homopolypropylene resin. A hindered amine light stabilizer (Kimasorb 944: manufactured by BASF) was added in an amount of 0.2% by mass (2000 PPM) to the homopolypropylene resin. Such a resin material was extruded using a melt extruder to form a polypropylene transparent resin sheet 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, and the wet tension on the surface of the transparent resin sheet was set to 40 dyn / cm or more.

(Base material forming process)
A base material on which two layers of a surface layer and a second base material layer were laminated was formed by forming a film by an extrusion method and stretching. That is, the decorative sheet base material was composed of two thermoplastic resin layers.
A layer serving as a precursor of the first surface layer was formed with 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, on the layer serving as the precursor of the first surface layer, the layer serving as the precursor of the second base material layer of the second layer is added to the resin material E (homopolypropylene, melting point 160 having an inorganic pigment added). And a thickness of 60 μm. As a result, a laminated resin precursor having a total thickness of two layers of 120 μm was formed.
Subsequently, the laminated resin precursor was stretched 4 times by a uniaxial stretching method to form a base material having a thickness of 30 μm (a surface layer thickness of 15 μm and a second base material layer thickness of 15 μm).

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

(Printing layer and primer layer forming step)
On the surface layer of the substrate, pattern printing was performed by a gravure printing method to form a printed layer. The printing layer is a two-component urethane ink (V180; manufactured by Toyo Ink Manufacturing Co., Ltd.), and 0.5% by mass of a hindered amine light stabilizer (Kimasorb 944; manufactured by BASF) based on the binder resin content of the ink. Formed with added ink.
Moreover, the primer layer was formed in the back surface of the 2nd base material layer of a base material. The primer layer was formed by printing the same two-component urethane ink as the printing layer by a gravure printing method.

(Transparent resin layer forming process)
Subsequently, an adhesive for dry lamination (Takelac A540; manufactured by Mitsui Chemicals, Inc .; application amount 2 g / m ² ) was applied as an adhesive layer to the front surface (printing layer forming surface) of the substrate. Then, the transparent resin layer was formed by bonding a transparent resin sheet to the front surface of a base material through the adhesive layer by the dry lamination method. The surface of the transparent resin layer was embossed.

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

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

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

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

<Sample 8>
A decorative sheet was formed in the same manner as in Sample 1, except that a base material without a second base material layer was used so that 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 a base material not provided with the second base material layer is used, and the embossing roll temperature is set. A decorative sheet was formed in the same manner as Sample 1 except that the temperature was 125 ° C.

<Sample 10>
A decorative sheet was formed in the same manner as Sample 1, except that the thickness of the second base material layer after stretching was 30 μm, a base material without a surface layer was used, and the embossing roll temperature was 150 ° C.
<Sample 11>
A decorative sheet is formed in the same manner as Sample 1, except that the second base material layer is formed with a thickness of 30 μm without stretching, a base material without a surface layer is used, and the embossing roll temperature is 150 ° C. Formed.

<Sample 12>
A decorative sheet was prepared in the same manner as in Sample 1, except that the second substrate layer was formed at a thickness of 60 μm without stretching, a substrate without a surface layer was used, and the embossing roll temperature was 150 ° C. Formed.
<Sample 13>
A decorative sheet is formed in the same manner as Sample 1, except that the second base material layer is formed with a thickness of 60 μm without stretching, a base material without a surface layer is used, and embossing is not performed. did.

<Sample 14>
A decorative sheet was formed in the same manner as Sample 1, except that the thickness of the second base material layer after stretching was 30 μm, a base material without a surface layer was used, and embossing was not performed.
<Sample 15>
A decorative sheet was formed in the same manner as Sample 1 except that embossing was not performed.

<Performance evaluation of decorative sheet>
The performance of each sample decorative sheet was evaluated.
[Tensile modulus]
The elastic sheet was measured by pulling the decorative sheet of each sample with a Tensilon universal material testing machine at 50 mm / min.
The evaluation of the elastic modulus is as follows.
○: Good (elastic modulus 500 MPa or more)
X: Defect (elastic modulus less than 500 MPa)

[Nonflammability test]
Using the decorative sheet of each sample, a heat generation test was conducted using a cone calorimeter tester in accordance with ISO5660-1. Nonflammability was judged by whether or not the provisions of Article 108-2 No. 1 and No. 2 of the Building Standards Law Enforcement Ordinance were satisfied.
The evaluation of nonflammability is as follows.
○: Good (within standard)
×: Defect (non-standard)

[Interlayer adhesion test]
The interlayer adhesion test is a test for evaluating the adhesion between the transparent resin layer and the substrate. The interlayer adhesion test was performed according to JIS K 6854-2 using the decorative sheet of each sample.
Evaluation of interlayer adhesion is as follows.
A: Very good (within standard)
○: Good (within standard)
Δ: Adhesive strength for practical use (within standard)
×: Defect (non-standard)
[Transparency test]
The transparency test is a test for evaluating the design of the decorative sheet. In the transparency test, the transmittance of the decorative sheet of each sample was measured by a spectrophotometer and evaluated.
The light transmittance is evaluated as follows.
○: Concealment is good (within standard)
×: Concealment is poor (non-standard)
Table 1 below shows the results of each evaluation.

As can be seen from Table 1, Sample 1 to Sample 5 which have a surface layer and a second base material layer, and the melting point of the resin constituting the surface layer is lower by 20 ° C. or more than the melting point of the second base material layer. This decorative sheet was excellent in elastic modulus, nonflammability, and interlayer adhesion.
Further, the decorative sheets of Sample 1 to Sample 4 containing pigments in the surface layer and the second base material layer are lighter than the decorative sheets of Sample 5 in which the surface layer and the second base material layer do not contain the pigment. The transmittance was low and the hiding property 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 is higher than the melting point of the second base material layer has an insufficient elastic modulus. Similarly, the decorative sheet of Sample 7 in which the difference in melting point between the surface layer of the substrate and the second substrate layer was less than 20 ° C. was not sufficient in elasticity. Also for the decorative sheets from Sample 8 to Sample 11 in which the base material had only either the surface layer or the second base material layer, the elastic modulus was not sufficient. From this result, in order to improve the strength of the decorative sheet, it has a surface layer and a second substrate layer, and the melting point of the resin constituting the surface layer is 20 compared to the melting point of the second substrate layer. It was found that the temperature needs to be lower than ℃.
Further, in the decorative sheet having only the second base material layer having a thickness of 30 μm and a melting point of 160 ° C. without providing a surface layer as in the sample 14, when the base material is stretched, embossing is performed. In the absence, interlayer adhesion decreased.

On the other hand, the decorative sheet not subjected to stretching processing on the base material and having no embossed structure as in sample 13 had sufficient interlayer adhesion, but as can be seen from sample 15, If it has a surface layer and a second base material layer, and the melting point of the resin constituting the surface layer is set to 20 ° C. or more lower than the melting point of the second base material layer, even without embossing, It was found that the interlayer adhesion sufficient to withstand practical use was ensured. Furthermore, it becomes possible to improve the interlayer adhesiveness of a decorative sheet by embossing like sample 1 grade | etc.,.
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 was particularly good in interlayer adhesion because it was not stretched. However, the decorative sheet of Sample 11 in which the film thickness of the second base material layer is 30 μm did not have sufficient elastic modulus. In addition, the decorative sheets of Samples 12 and 13 in which the film thickness of the second base material layer was 60 μm had a sufficient elastic modulus because the film thickness of the second base material layer was thicker than the decorative sheet of Sample 11. However, nonflammability decreased. From this result, it was found that, when stretching (thinning) was not performed in order to compensate for a decrease in interlayer adhesion due to stretching, it was difficult to achieve both the strength and nonflammability of the decorative sheet.

From the above results, the decorative sheet having the surface layer and the second base material layer, the melting point of the resin constituting the surface layer being lower by 20 ° C. or more than the melting point of the second base material layer, Excellent incombustibility 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 lower by 20 ° C. or more than the melting point of the second base material layer, the elastic modulus (base It can solve the problems of both (material strength) and interlayer adhesion (durability). Moreover, it turned out that a low light transmittance (high concealment property) is further acquired by the surface layer and the 2nd base material layer containing an inorganic pigment.
Although the present invention has been described above by the embodiments, the scope of the present invention is not limited to the illustrated and described exemplary embodiments, and brings about effects equivalent to those intended by the present invention. All embodiments are also included. Further, the scope of the invention is not limited to the combinations of features of the invention defined by the claims, but can be defined by any desired combination of specific features among all the disclosed features.

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

Claims

A uniaxial or biaxial laminated stretched film,
When the first layer 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 A laminated stretched film characterized by being 20 ° C. or more lower than the melting point of the resin of the thermoplastic resin layer other than the layer.
The lamination stretching according to claim 1, wherein the melting point of the resin of the surface layer is lower than the melting point of the resin of the thermoplastic resin layer other than the surface layer within a range of 20 ° C or higher and 70 ° C or lower. the film.
3. The laminated stretched film according to claim 1 or 2, wherein the thermoplastic resin is a polyolefin resin.
3. The laminated stretched film according to claim 1 or 2, wherein the thermoplastic resin is a polypropylene resin.
The laminated drawing according to any one of claims 1 to 3, wherein the surface layer further includes polypropylene having a mesopentad fraction in a range of 30% or more and less than 50% as a soft material. the film.
The surface layer is made of polypropylene having a mesopentad fraction in the range of 30% or more and less than 50%, and the resin constituting the surface layer is 5 parts by mass or more with respect to 100 parts by mass of the resin having the highest content. The laminated stretched film according to claim 5, which is contained within a range of less than 30 parts by mass.
A decorative sheet base material comprising the laminated stretched film according to any one of claims 1 to 6.
In the exothermicity test with a cone calorimeter tester conforming to ISO5660-1 in a state of being bonded to a non-combustible base material, the requirements described in Article 108-2 No. 1 and No. 2 of the Building Standard Act Enforcement Ordinance are satisfied. The base material for decorative sheets according to claim 7, which is a non-combustible material.
The base material for a decorative sheet according to claim 7 or claim 8, and one or more transparent resin layers including a polyolefin-based resin formed on the surface layer side surface of the base material for the decorative sheet. A decorative sheet comprising:
A decorative board comprising the decorative sheet according to claim 9 provided on a wooden substrate.