JP5045180B2 - Manufacturing method of decorative sheet for flooring - Google Patents

Description

  The present invention relates to a method for producing a decorative sheet for flooring.

  The decorative sheet for flooring is used for the purpose of decorating the surface of the base material by sticking it to a base material (for example, a wooden base material such as plywood) disposed on the floor surface. Such a decorative sheet for flooring is required to have excellent properties such as caster resistance and impact resistance in addition to the decorative performance. The caster resistance indicates resistance to a load applied to the surface of the decorative sheet for flooring by a caster (wheel) such as an office chair.

  As a decorative sheet for flooring, for example, a decorative layer is provided on the base material sheet, and a synthetic resin backer layer is further provided on the back surface of the base material sheet, so that characteristics such as caster resistance and impact resistance are exhibited as a whole. There is known a decorative sheet for flooring (Patent Document 1, etc.). Note that the backer layer is a synthetic resin layer having a relatively large thickness, which is effective for the expression of the above-mentioned characteristics while mitigating the influence of surface irregularities such as a wooden substrate.

  Conventionally, the decorative sheet for flooring having a backer layer has been manufactured by pasting a backer layer on the back surface of a base sheet by dry lamination or the like. There is a problem that it is easy and takes a long time to paste, and is not suitable for mass production.

  In view of the above problems, there is an attempt to form a decorative sheet for flooring by forming a relatively thick transparent resin layer on a base sheet without forming a backer layer (Patent Document 2 and the like). Since a thick resin layer is laminated, there is a limit to the production speed, and there is room for further improvement in terms of productivity.

  In addition to the above, a method for producing a decorative sheet for floors for forming a backer layer, in which a backer layer is formed by extrusion of a molten resin, has also been proposed. However, this manufacturing method creates new problems. That is, since the molten resin is hot, high temperature heat is transmitted to the base sheet side, and the embossed pattern on the decorative sheet surface disappears due to heat.

Therefore, it is desired to develop a method for producing a decorative sheet for flooring that has excellent properties such as caster resistance and impact resistance, and that does not impair other properties.
JP 2003-239517 A JP 2005-290568 A

  The present invention is a method for producing a decorative sheet for flooring that has excellent properties such as caster resistance and impact resistance, and an object thereof is to provide an efficient production method.

  As a result of intensive studies to achieve the above object, the present inventor made the above object when the thickness of the decorative sheet for flooring is within a specific range and the backer layer is laminated by a specific method. The inventors have found that this can be achieved and have completed the present invention.

  That is, this invention relates to the manufacturing method of the following decorative sheet for flooring, and a flooring decorative material.

1. Production of a decorative sheet for flooring that has a pattern layer, a transparent adhesive layer, a transparent resin layer, and a transparent surface protective layer in this order on the base sheet, and has a synthetic resin backer layer on the back of the base sheet A method,
(1) The transparent resin layer has a thickness of 60 to 250 μm,
(2) The decorative sheet for flooring has a thickness of 300 to 580 μm,
(3) The decorative sheet for flooring is based on the back surface of the intermediate sheet in which the pattern layer, the transparent adhesive layer, the transparent resin layer, and the transparent surface protective layer are formed on the base material sheet. Obtained by forming a synthetic resin backer layer by extruding the molten resin in a thickness range of 80 to 250 μm ,
(4) At least one of the transparent resin layer and the synthetic resin backer layer contains a thermoplastic resin as a resin component.
A method for producing a decorative sheet for flooring.

2. Furthermore, the manufacturing method of said claim | item 1 with which an adhesive bond layer is formed between a synthetic resinous backer layer and a base material sheet.

  3. Item 3. The method according to Item 1 or 2, wherein the transparent resin layer contains polypropylene as a resin component.

  4). The manufacturing method according to any one of Items 1 to 3, wherein the transparent resin layer has a tensile modulus of elasticity of 600 MPa or more as measured according to JIS K6734.

  5). The manufacturing method according to any one of Items 1 to 4, wherein the synthetic resin backer layer has a tensile elastic modulus measured according to JIS K6734 of 1000 MPa or more.

  6). Item 6. The method according to any one of Items 1 to 5, wherein the transparent surface protective layer contains an ionizing radiation curable resin as a resin component.

  7). Item 7. The production method according to any one of Items 1 to 6, wherein the base sheet contains a polyolefin-based resin as a resin component.

  Hereinafter, the present invention will be described in detail.

Manufacturing method of decorative sheet for flooring The manufacturing method of a decorative sheet for flooring of the present invention has a pattern layer, a transparent adhesive layer, a transparent resin layer, and a transparent surface protective layer in this order on a base sheet. And a method for producing a decorative sheet for flooring having a synthetic resin backer layer on the back surface of the base sheet,
(1) The transparent resin layer has a thickness of 60 to 250 μm,
(2) The decorative sheet for flooring has a thickness of 300 to 580 μm,
(3) The decorative sheet for flooring is based on the back surface of the intermediate sheet in which the pattern layer, the transparent adhesive layer, the transparent resin layer, and the transparent surface protective layer are formed on the base material sheet. The molten resin is obtained by forming a synthetic resin backer layer by extruding the molten resin in a thickness range of 80 to 250 μm.

  According to the manufacturing method of the present invention having the above characteristics, the decorative material for flooring is formed without losing the embossed pattern formed on the surface of the decorative sheet, even though the synthetic resin backer layer is formed by extrusion molding of the molten resin. Sheets can be manufactured. In addition, by adopting the thickness conditions defined in (1) to (3) above, the decorative sheet for flooring has good properties such as caster resistance and impact resistance.

  In the production method of the present invention, first, an intermediate sheet in which a pattern layer, a transparent adhesive layer, a transparent resin layer, and a transparent surface protective layer are formed on a base sheet is prepared. Next, a synthetic resin backer layer is formed by extruding a molten resin (melted synthetic resin) in a thickness range of 80 to 250 μm on the back surface of the base material sheet of the intermediate sheet.

  The configuration of the intermediate sheet is as follows.

(Base material sheet)
Although it does not limit as a base material sheet, the base material sheet which contains polyolefin resin as a resin component is preferable. Essentially, a sheet made of polyolefin resin is used.

  It does not specifically limit as polyolefin resin, What is normally used in the field | area of a decorative sheet can be used. For example, polyethylene, polypropylene, polybutene, polymethylpentene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-propylene-butene copolymer, polyolefin-based thermoplastic elastomer, etc. Is mentioned. Among these, polypropylene, polyolefin-based thermoplastic elastomers and the like are particularly preferable.

  A homopolymer or copolymer having polypropylene as a main component is also preferable, for example, a homopolypropylene resin, a random polypropylene resin, a block polypropylene resin, and a polypropylene crystal part and having 2 to 20 carbon atoms other than propylene. -Olefins. In addition, a propylene-α-olefin copolymer containing 15 mol% or more of a comonomer of ethylene, butene-1,4-methylpentene-1, hexene-1, or octene-1 is also preferable.

  The polyolefin-based thermoplastic elastomer is preferably a mixture of isotactic polypropylene in the hard segment and atactic polypropylene in the soft segment in a weight ratio of 80:20.

  The polyolefin resin may be formed into a film by, for example, a calendar method, an inflation method, a T-die extrusion method, or the like.

  The thickness of the base sheet is not particularly limited and can be set according to the product characteristics, but is usually 40 to 150 μm, preferably about 50 to 100 μm.

  An additive may be mix | blended with a base material sheet as needed. Examples of the additive include a filler such as calcium carbonate and clay, a flame retardant such as magnesium hydroxide, an antioxidant, a lubricant, a foaming agent, and a colorant (see below). The blending amount of the additive can be appropriately set according to the product characteristics.

  It does not specifically limit as a coloring agent, Well-known coloring agents, such as a pigment and dye, can be used. For example, inorganic pigments such as titanium white, zinc white, petal, vermilion, ultramarine blue, cobalt blue, titanium yellow, yellow lead, carbon black; isoindolinone, Hansa Yellow A, quinacridone, permanent red 4R, phthalocyanine blue, indanthrene Organic pigments (including dyes) such as blue RS and aniline black; metal pigments such as aluminum and brass; pearlescent pigments made of foil powder such as titanium dioxide-coated mica and basic lead carbonate. The coloring mode of the base sheet includes transparent coloring and opaque coloring (hiding coloring), and these can be arbitrarily selected. For example, when the ground color of an adherend (a base material on which a decorative sheet is pasted, such as a wooden base material) is concealed, opaque coloring may be selected. On the other hand, in order to make the ground pattern of the adherend visible, transparent coloring may be selected.

  One or both surfaces of the base sheet may be subjected to surface treatment such as corona discharge treatment, ozone treatment, plasma treatment, ionizing radiation treatment, dichromic acid treatment, etc., as necessary. For example, when the corona discharge treatment is performed, the surface tension of the substrate sheet surface may be 30 dyne or more, preferably 40 dyne or more. The surface treatment may be performed according to a conventional method for each treatment.

  A primer layer (for example, a back primer layer for facilitating adhesion of a backer layer, a primer layer for facilitating the formation of a pattern layer) is provided on one or both sides of the base sheet as necessary. May be.

  A primer layer can be formed by apply | coating a well-known primer agent to the single side | surface or both surfaces of a base material sheet. Examples of the primer agent include a urethane resin primer agent made of acrylic modified urethane resin, a primer agent made of urethane-cellulose resin (for example, a resin made by adding hexamethylene diisocyanate to a mixture of urethane and nitrified cotton), and the like. Is mentioned.

Although the application amount of the primer agent is not particularly limited, it is usually 0.1 to 100 g / m ² , preferably about 0.1 to 50 g / m ² .

  Although the thickness of a primer layer is not specifically limited, Usually, 0.01-10 micrometers, Preferably it is about 0.1-1 micrometer.

(Pattern pattern layer)
A pattern layer is formed on the base sheet (opposite to the surface on which the backer layer is formed).

  The design pattern layer imparts design properties with a desired design to the decorative sheet, and the type of design is not particularly limited. Examples thereof include a wood grain pattern, a stone pattern, a grain pattern, a tiled pattern, a brickwork pattern, a cloth pattern, a leather pattern, a geometric figure, a character, a symbol, and an abstract pattern.

  The method for forming the pattern layer is not particularly limited. For example, a colored ink or coating obtained by dissolving (or dispersing) a known colorant (dye or pigment) in a solvent (or dispersion medium) together with a binder resin. What is necessary is just to form by the printing method etc. which used the agent etc.

  Examples of the colorant include inorganic pigments such as carbon black, titanium white, zinc white, dial, bitumen, and cadmium red; azo pigments, lake pigments, anthraquinone pigments, quinacridone pigments, phthalocyanine pigments, isoindolinone pigments, dioxazine pigments. Organic pigments such as aluminum powder, metal powder pigments such as bronze powder, pearlescent pigments such as titanium oxide-coated mica and bismuth oxide chloride; fluorescent pigments; These colorants can be used alone or in admixture of two or more. These colorants may further contain fillers such as silica, extender pigments such as organic beads, neutralizing agents, surfactants and the like.

  Examples of the binder resin include acrylic resin, styrene resin, polyester resin, urethane resin, chlorinated polyolefin resin, vinyl chloride-vinyl acetate copolymer resin, polyvinyl butyral resin, alkyd resin, petroleum Resin, ketone resin, epoxy resin, melamine resin, fluorine resin, silicone resin, fiber derivative, rubber resin and the like. These resins can be used alone or in admixture of two or more.

  Examples of the solvent (or dispersion medium) include petroleum organic solvents such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; ethyl acetate, butyl acetate, 2-methoxyethyl acetate, and acetic acid-2 -Ester-based organic solvents such as ethoxyethyl; alcohol-based organic solvents such as methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, isobutyl alcohol, ethylene glycol, propylene glycol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone Organic solvents; ether organic solvents such as diethyl ether, dioxane, tetrahydrofuran; dichloromethane, carbon tetrachloride, trichloroethylene, tetrachloroethylene Inorganic solvents and the like, such as water; chlorinated organic solvents. These solvents (or dispersion media) can be used alone or in admixture of two or more.

  Examples of the printing method used for forming the pattern layer include a gravure printing method, an offset printing method, a screen printing method, a flexographic printing method, an electrostatic printing method, and an inkjet printing method. When forming a solid pattern pattern layer, for example, roll coating method, knife coating method, air knife coating method, die coating method, lip coating method, comma coating method, kiss coating method, flow coating method, dip coating Various coating methods such as a coating method may be mentioned. In addition, the hand-drawn method, the ink-sink method, the photographic method, the transfer method, the laser beam drawing method, the electron beam drawing method, the metal partial evaporation method, the etching method, etc. may be used or combined with other forming methods. Good.

  The thickness of the pattern layer is not particularly limited and can be set as appropriate according to product characteristics. The layer thickness at the time of coating is about 1 to 15 μm, and the layer thickness after drying is about 0.1 to 10 μm.

(Colored hiding layer)
A colored concealment layer may be further formed between the base sheet and the pattern layer as necessary. The colored masking layer is provided when it is desired to mask the ground color of the adherend from the front surface of the decorative sheet. Of course, when the base sheet is transparent, even when the base sheet is concealed, it may be formed to stabilize the concealment.

  As the ink for forming the colored masking layer, an ink for forming a pattern layer and capable of masking coloring can be used.

  The method for forming the colored concealment layer is preferably a method that can be formed so as to cover the entire base sheet (entirely solid). For example, the roll coating method, knife coating method, air knife coating method, die coating method, lip coating method, comma coating method, kiss coating method, flow coating method, dip coating method and the like described above are preferable.

  The thickness of the colored concealing layer is not particularly limited and can be set as appropriate according to the product characteristics. The layer thickness during coating is about 0.2 to 10 μm, and the layer thickness after drying is about 0.1 to 5 μm.

(Transparent adhesive layer)
A transparent adhesive layer is formed on the pattern layer. The transparent adhesive layer is not particularly limited as long as it is transparent, and includes any of transparent and colorless, colored and translucent. The transparent adhesive layer is formed in order to bond the pattern layer and the transparent resin layer.

  It does not specifically limit as an adhesive agent, A well-known adhesive agent can be used in the field of a decorative sheet.

  Examples of the adhesive known in the field of decorative sheets include thermoplastic resins such as polyamide resin, acrylic resin and vinyl acetate resin, and curable resins such as thermosetting urethane resin. Further, a two-component curable polyurethane resin or polyester resin using isocyanate as a curing agent can also be applied.

  The adhesive layer can be formed, for example, by applying an adhesive on the pattern layer, applying a coating agent (adhesive) that constitutes the transparent resin layer, and drying and curing. Conditions such as drying temperature and drying time are not particularly limited, and may be set as appropriate according to the type of adhesive. The method of applying the adhesive is not particularly limited, and examples thereof include roll coating, curtain flow coating, wire bar coating, reverse coating, gravure coating, gravure reverse coating, air knife coating, kiss coating, blade coating, smooth coating, and comma coating. The method can be adopted.

  Although the thickness of an adhesive bond layer is not specifically limited, The thickness after drying is 0.1-30 micrometers, Preferably it is about 1-20 micrometers.

(Transparent resin layer)
A transparent resin layer having a thickness of 60 to 250 μm is formed on the transparent adhesive layer. If it is the range (preferably 100-250 micrometers, more preferably 150-250 micrometers) of the said thickness, the decorative sheet for flooring is easy to ensure the outstanding scratch resistance. The transparent resin layer includes any of colorless and transparent, colored and transparent, and translucent as long as it is transparent.

  The resin component contained in the transparent resin layer is not limited, but is preferably a thermoplastic resin, particularly preferably polypropylene, and more preferably homopolypropylene. It is preferable that the transparent resin layer is substantially formed of the polypropylene resin.

  The transparent resin layer preferably has a tensile elastic modulus of 600 MPa or more, and preferably 1000 MPa or more. The upper limit of the tensile elastic modulus is not particularly limited, but may be about 2000 MPa. In addition, the tensile elastic modulus in this specification refers to the tensile elastic modulus of a sample (for example, a transparent resin layer in this case) according to JIS K6734 “Plastics—Rigid polyvinyl chloride sheet—Dimensions and characteristics—Part 2: Thickness less than 1 mm It is a value measured in accordance with the provisions of “No. The JIS (Japanese Industrial Standards) refers to Japanese Industrial Standards. Specifically, when both ends (A and B in FIG. 1) of the sample punched into the shape shown in FIG. 1 are pulled at a speed of 50 mm / min using a tensile tester (Tensilon universal tester RTC-1250A). Further, it is a value obtained by reading the tensile elastic modulus (MPa) when the sample is cut at the central portion.

  The transparent resin layer is formed, for example, from the above polypropylene resin by a calendar method, an inflation method, a T-die extrusion method, or the like. An existing film may be used.

  The transparent resin layer may contain a weathering agent as necessary. As the weathering agent, for example, an ultraviolet absorber, a hindered amine light stabilizer and the like are preferable. These weathering agents can be used alone or in admixture of two or more. In particular, when the transparent resin layer contains polypropylene, it is preferable to contain a weathering agent.

  Examples of the ultraviolet absorber include benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, and triazine ultraviolet absorbers. As the light stabilizer, for example, a hindered amine light stabilizer is suitable. The content of these weathering agents is not limited, but both the ultraviolet absorber and the light stabilizer may be about 1000 to 10,000 ppm by weight in the transparent resin layer.

  On the surface of the transparent resin layer, on which the transparent surface protective layer described later is formed, the surface of corona discharge treatment, ozone treatment, plasma treatment, ionizing radiation treatment, dichromate treatment, etc., as necessary Processing may be performed. The surface treatment may be performed according to a conventional method for each treatment.

  Moreover, you may provide a primer layer (primer layer for making formation of a surface protective layer easy) on the surface as needed.

  A primer layer can be formed by apply | coating a well-known primer agent to the single side | surface or both surfaces of a base material sheet. Examples of the primer agent include a urethane resin-based primer agent composed of an acrylic-modified urethane resin and the like, and a resin-based primer agent composed of a block copolymer of acrylic and urethane.

Although the application amount of the primer agent is not particularly limited, it is usually 0.1 to 100 g / m ² , preferably about 0.1 to 50 g / m ² .

  Although the thickness of a primer layer is not specifically limited, Usually, 0.01-10 micrometers, Preferably it is about 0.1-1 micrometer.

(Transparent surface protective layer)
A transparent surface protective layer is formed on the transparent resin layer. The transparent surface protective layer is not limited, but preferably contains an ionizing radiation curable resin or a two-component curable urethane resin as a resin component. Substantially those formed from these resins are preferred. When forming a transparent surface protective layer with ionizing radiation curable resin or two-component curable urethane resin, it is easy to improve the abrasion resistance, impact resistance, contamination resistance, scratch resistance, weather resistance, etc. of the decorative sheet. .

  The ionizing radiation curable resin is not particularly limited, and prepolymers (including oligomers) and / or monomers containing radically polymerizable double bonds capable of undergoing a crosslinking reaction upon irradiation with ionizing radiation such as ultraviolet rays and electron beams. A transparent resin containing as a main component can be used. These prepolymers or monomers can be used alone or in combination. The curing reaction is usually a cross-linking curing reaction.

  Specifically, as the prepolymer or monomer, a compound having in the molecule a radically polymerizable unsaturated group such as a (meth) acryloyl group or (meth) acryloyloxy group, or a cationically polymerizable functional group such as an epoxy group. Is mentioned. Further, a polyene / thiol prepolymer based on a combination of polyene and polythiol is also preferable. Here, the (meth) acryloyl group means an acryloyl group or a methacryloyl group.

  Examples of the prepolymer having a radically polymerizable unsaturated group include polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, melamine (meth) acrylate, triazine (meth) acrylate, and silicone (meth) acrylate. Etc. These molecular weights are usually preferably about 250 to 100,000.

  As a monomer which has a radically polymerizable unsaturated group, methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, phenoxyethyl (meth) acrylate etc. are mentioned as a monofunctional monomer, for example. Examples of the polyfunctional monomer include diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethylene oxide tri (meth) acrylate, dipentaerythritol tetra ( And (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate.

  Examples of the prepolymer having a cationic polymerizable functional group include prepolymers of epoxy resins such as bisphenol type epoxy resins and novolac type epoxy compounds, and vinyl ether type resins such as fatty acid type vinyl ethers and aromatic vinyl ethers. Examples of the thiol include polythiols such as trimethylolpropane trithioglycolate and pentaerythritol tetrathioglycolate. Examples of the polyene include those in which allyl alcohol is added to both ends of polyurethane by diol and diisocyanate.

  As the ionizing radiation used for curing the ionizing radiation curable resin, electromagnetic waves or charged particles having energy capable of causing a curing reaction of molecules in the ionizing radiation curable resin (composition) are used. Usually, ultraviolet rays or electron beams may be used, but visible light, X-rays, ion rays, or the like may be used.

  As the ultraviolet light source, for example, a light source such as an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light, a metal halide lamp can be used. As a wavelength of ultraviolet rays, 190 to 380 nm is usually preferable.

  As the electron beam source, for example, various electron beam accelerators such as a cockcroft Walton type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type can be used. Among them, those capable of irradiating electrons having energy of 100 to 1000 keV, preferably 100 to 300 keV are preferable.

  The two-component curable urethane resin is not particularly limited. Among them, a polyol component (acrylic polyol, polyester polyol, polyether polyol, epoxy polyol, etc.) having an OH group as a main component and an isocyanate component (tolylene diene) which is a curing agent component. Isocyanate, hexamethylene diisocyanate, metaxylene diisocyanate and the like) can be used.

  The surface protective layer may contain an anti-glare agent, a plasticizer, a stabilizer, a filler, a dispersant, a colorant such as a dye and a pigment, a solvent, and the like, if necessary. About the kind in case of containing a weathering agent and content, it is the same as that of the description in a transparent resin layer.

  The surface protective layer is formed by, for example, applying an ionizing radiation curable resin or a two-component curable urethane resin on a transparent polypropylene resin layer by a known coating method such as gravure coating or roll coating, and then curing the resin. Can be formed. In the case of an ionizing radiation curable resin, the resin is cured by electron beam irradiation.

  The thickness of the surface protective layer is not particularly limited and can be appropriately set according to the characteristics of the final product, but is usually about 0.1 to 50 μm, preferably about 1 to 20 μm.

  Irregularities may be formed on the front surface (surface exposed to the atmosphere) of the surface protective layer. Usually, an uneven pattern is formed by embossing. The embossing method is not particularly limited. For example, a preferable method is to heat soften the front surface of the transparent acrylic resin layer, pressurize and shape with an embossing plate, and then cool. For embossing, a known single-wafer or rotary embossing machine is used. Examples of the concavo-convex shape include a wood grain plate conduit groove, a stone plate surface unevenness (such as granite cleaved surface), a cloth surface texture, a satin texture, a grain, a hairline, a ridge line, and the like.

  In the production method of the present invention, a synthetic resin backer layer is formed by extruding a molten resin in a thickness range of 80 to 250 μm on the back surface of the base sheet of the intermediate sheet described above. By extruding the molten resin within such a range, the synthetic resin backer layer can be formed on the back surface of the base material sheet without losing the embossed pattern formed on the surface of the intermediate sheet.

  When the synthetic resin backer layer is formed by extrusion molding of a molten resin, for example, extrusion molding using a T die can be suitably used. When the synthetic resin backer layer is a multilayer, for example, a multi-manifold type or feed block type T-die may be used to perform multilayer simultaneous extrusion. When the synthetic resin backer layer is a multilayer, for example, the layer closest to the back surface of the base sheet is preferably an easily adhesive resin layer. Such an improvement can be achieved by, for example, blending a known thermoplastic elastomer into a layer that forms an easily adhesive resin layer. The type of the thermoplastic elastomer is not particularly limited, and can be widely selected from those that have high compatibility with the resin constituting the backer layer and can contribute to improvement in adhesion to the base sheet.

  In addition, when the synthetic resin backer layer formed by extrusion molding is difficult to adhere to the back surface of the base sheet only by thermal fusion, an adhesive layer may be interposed as necessary to enhance the adhesion. . Although the kind of adhesive is not limited, what was described in the column of the said transparent adhesive layer can be used. The thickness of the adhesive layer is not limited, but is about 0.1 to 30 μm. When forming the adhesive layer, the thickness of the adhesive layer is also included in the thickness of the decorative sheet for flooring.

  The synthetic resin for forming the backer layer is not limited, but a thermoplastic resin is preferable. For example, polypropylene, ethylene-vinyl alcohol copolymer, polymethylene, polymethylpentene, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyarylate , Polyethylene naphthalate-isophthalate copolymer, polyimide, polystyrene, polyamide, ABS and the like.

  The thickness of the synthetic resin backer layer may be 80 to 250 μm, preferably about 100 to 250 μm, and more preferably 150 to 250 μm. Thus, it is desirable that the thickness is as large as the conditions allow within the range of 80 to 250 μm. The synthetic resin backer layer may be a single layer or multiple layers as long as it is formed by extrusion molding. The synthetic resin may be used alone or as a mixture.

  The synthetic resin backer layer preferably has a tensile elastic modulus of 1000 MPa or more, and preferably 1500 MPa or more. The upper limit of the tensile elastic modulus is not particularly limited, but may be about 2500 MPa.

  The decorative sheet for flooring of the present invention obtained by forming a synthetic resin backer layer by the above method needs to have a thickness of 300 to 580 μm. The thickness range includes the thickness of an arbitrary layer such as a primer layer.

Flooring decorative material The flooring decorative sheet of the present invention can be made into a flooring decorative material by bonding with various adherends. The material of the adherend is not particularly limited, and examples thereof include inorganic non-metallic materials, metallic materials, wood materials, and plastic materials.

  Specifically, in inorganic non-metallic systems, for example, papermaking cement, extruded cement, slag cement, ALC (lightweight cellular concrete), GRC (glass fiber reinforced concrete), pulp cement, wood chip cement, asbestos cement, calcium oxalate, Non-ceramic ceramic materials such as gypsum and gypsum slag, ceramic materials such as earthenware, ceramics, porcelain, setware, glass, and glazing.

  In a metal system, metal materials (metal steel plate), such as iron, aluminum, and copper, are mentioned, for example.

  In the wood system, for example, a single board, plywood, particle board, fiber board, laminated timber and the like made of cedar, straw, firewood, lauan, teak and the like can be mentioned.

  In the plastic system, for example, resin materials such as polypropylene, ABS resin, and phenol resin can be used.

  The shape of such an adherend is not particularly limited, and may be a flat plate in consideration of installation on a flooring or the like.

  After joining with the adherend, for example, according to the characteristics of the final product, cutting, use of a tenor, sag processing, provision of V-shaped grooves, chamfering on four sides, etc. may be performed.

  According to the production method of the present invention, the decorative sheet for flooring is produced without losing the embossed pattern formed on the surface of the decorative sheet, even though the synthetic resin backer layer is formed by extrusion molding of the molten resin. be able to. Moreover, by adopting the thickness conditions specified in the above (1) to (3), the resulting decorative sheet for flooring has good properties such as caster resistance and impact resistance.

  Experimental examples will be shown below to describe the present invention more specifically.

Reference Example 1, Examples 1-3 and Comparative Examples 1-4
(Preparation of decorative sheet for flooring)
A pattern layer (2 μm) was formed by printing on 0.06 mm thick colored polypropylene (base sheet). Next, a 0.08 mm-thick transparent polypropylene resin film (transparent resin layer) was bonded onto the pattern layer using a urethane dry laminate adhesive. The thickness of the transparent adhesive layer was 3 μm. Next, an electron beam curable transparent surface protective layer (15 μm) was formed on the transparent resin layer. Next, embossing was performed from the transparent surface protective layer side to produce an intermediate sheet. In embossing, a grain conduit pattern with a depth of about 30 μm was applied. Finally, a urethane adhesive is applied to the back surface of the intermediate sheet, and a transparent polypropylene-based resin layer (synthetic resin backer layer) having the thickness shown in Table 1 below is extruded and simultaneously laminated. Was made. The resin temperature at the time of melt extrusion was 240 ° C.
(Preparation of decorative materials for floors)
A 12 mm lauan plywood was stuck to the back surface (synthetic resin backer layer side) of the produced decorative sheet for flooring to prepare a flooring decorative material. A urethane-modified ethylene-vinyl acetate emulsion adhesive (9 g / scale ² wet) was used for the attachment.

[In Table 1, the numerical value of Reference Example 1 indicates the characteristics that the floor decorative material of the example should satisfy]
(Embossed state)
It was confirmed by naked eye observation whether the embossed pattern of the produced decorative material for floor had disappeared due to heat during lamination of the synthetic resin backer layer.

A case where the embossed pattern remained clearly was evaluated as “Good”. The case where the embossed pattern remained almost was evaluated as O to Δ. The case where the embossed pattern almost disappeared was evaluated as Δ to ×. The case where the embossed pattern completely disappeared was evaluated as x. The evaluation results are also shown in Table 1.
(DuPont impact test)
The impact resistance of the produced floor decorative material was evaluated using a DuPont impact tester (based on JIS K5600-5-3). Specifically, evaluation was performed by dropping a weight having a specified weight from a height of 30 cm onto the surface of the decorative material and measuring the amount of dents. The test results are also shown in Table 1.
(Caster resistance test)
The caster resistance of the produced floor decorative material was evaluated using a caster resistance test apparatus L6-04 (manufactured by Asano Machinery Manufacturing Co., Ltd.). Specifically, after moving the caster on the floor decorative material, the depth of the concave portion attached to the floor decorative material was measured with a depth meter by visual observation. The test results are also shown in Table 1.

≪Specifications of caster resistance test equipment≫
・ Sample fixing base: Φ80cm, thickness 8mm made of acrylic ・ Three casters: Hammer caster 420SA-N75 (Φ75mm × 25mm, wheel nylon)
・ Rotating speed of caster fixing base: 0 to 60 rpm (variable motor drive type)
・ Loading part: Adjustable to 40-210kg ・ Adjusting handle: The caster moves up and down by turning the handle on the weight base ・ Rotation direction reversal interval: 1-12 minutes (can be set by timer)
・ Preset counter: Setting of rotation speed and cumulative rotation speed ・ Digital tachometer: Display of caster rotation speed ・ Sample size: 30cm × 30cm
≪Caster resistance test conditions≫
In the caster resistance test apparatus, the floor decorative material to be tested was fixed to a sample fixing base. After the caster fixing base was raised by the adjustment handle so that the three casters did not contact the surface of the flooring decorative material, a weight was placed on the load base so that the weight would be 70 kg. The rotational speed was set to 20 rpm, counter-rotation every 5 minutes, and 1000 rotations. The adjustment handle was turned to lower the caster fixing table onto the surface of the floor decorative material to be tested. The test was started by turning on the start switch of the rotary drive device of the caster fixed base. After completion of the test, the adjustment handle was turned to float the caster fixing base, and the floor decorative material to be tested was taken out and evaluated.
(Pencil hardness test)
The pencil hardness of the produced floor decorative material was measured using a pencil hardness tester. The test was performed in accordance with JIS K5600-5-4 except that the test machine was set so as to apply a load of 1000 g to the tip of the pencil when the test machine was in the horizontal position. The test results are also shown in Table 1.
(Clemens scratch test)
A Clemens scratch test was performed on the produced floor decorative material. Specifically, the test was conducted according to JIS K5600-5-5. As a needle for scratching the surface of the decorative material, a needle made of diamond was used. The test results (maximum load at which no whitening damage occurs: g) are also shown in Table 1.
(Discussion)
From Table 1, it can be seen that when the thickness of the synthetic resin backer layer is 300 μm or more, the embossed pattern disappears remarkably.

Comparative Examples 5-9
A flooring decorative material was produced in the same manner as in Comparative Example 3 except that the thickness of the backer layer was fixed to 300 μm and the thickness of the transparent resin layer was changed to the thickness shown in Table 2 below.

  It was confirmed by naked eye observation whether the embossed pattern of the produced decorative material for floor had disappeared due to heat during lamination of the synthetic resin backer layer. Evaluation methods and evaluation criteria are as described above. The test results are also shown in Table 2.

(Discussion)
From Table 2, it can be seen that when the thickness of the synthetic resin backer layer is 300 μm or more, the embossed pattern disappears remarkably regardless of the thickness of the transparent resin layer.

Examples 4-6 and Comparative Examples 10-11
A flooring decorative material was produced in the same manner as in Comparative Example 1 except that the thickness of the backer layer was fixed at 80 μm and the thickness of the transparent resin layer was changed to the thickness shown in Table 3 below. Further, the embossed state, Dupont impact property, caster resistance, pencil hardness and Clemens scratch property were evaluated by the same method as described above. The test results are also shown in Table 3.

(Discussion)
Table 3 shows that when the thickness of the synthetic resin backer layer is constant, the scratch resistance improves as the thickness of the transparent resin layer increases. Further, it is considered that the impact test characteristic is caused by the total thickness of the decorative sheet, and it can be understood that the required characteristic is satisfied when the total thickness is 300 μm or more.

Examples 7 to 11 and Comparative Example 12
A flooring decorative material was produced in the same manner as in Example 4 except that the thickness of the transparent resin layer was fixed to 150 μm and the thickness of the synthetic resin backer layer was changed to the thickness shown in Table 4 below. Further, the embossed state, Dupont impact property, caster resistance, pencil hardness and Clemens scratch property were evaluated by the same method as described above. The test results are also shown in Table 4.

(Discussion)
From Table 4, it can be seen that when the thickness of the synthetic resin backer layer is 60 μm, the impact characteristics and the caster resistance characteristics are insufficient.

It is a schematic diagram (top view) which shows the shape of a sample in the case of measuring the tensile elasticity modulus of a sample according to prescription | regulation of JISK6734. In the figure, R60 indicates the degree of curvature.

Claims (7)

Production of a decorative sheet for flooring that has a pattern layer, a transparent adhesive layer, a transparent resin layer, and a transparent surface protective layer in this order on the base sheet, and has a synthetic resin backer layer on the back of the base sheet A method,
(1) The transparent resin layer has a thickness of 60 to 250 μm,
(2) The decorative sheet for flooring has a thickness of 300 to 580 μm,
(3) The decorative sheet for flooring is based on the back surface of the intermediate sheet in which the pattern layer, the transparent adhesive layer, the transparent resin layer, and the transparent surface protective layer are formed on the base material sheet. Obtained by forming a synthetic resin backer layer by extruding the molten resin in a thickness range of 80 to 250 μm ,
(4) At least one of the transparent resin layer and the synthetic resin backer layer contains a thermoplastic resin as a resin component.
A method for producing a decorative sheet for flooring. Furthermore, the manufacturing method of Claim 1 in which an adhesive bond layer is formed between a synthetic resinous backer layer and a base material sheet.   The production method according to claim 1, wherein the transparent resin layer contains polypropylene as a resin component.   The manufacturing method according to any one of claims 1 to 3, wherein the transparent resin layer has a tensile elastic modulus of 600 MPa or more as measured according to JIS K6734.   The manufacturing method according to any one of claims 1 to 4, wherein the synthetic resin backer layer has a tensile elastic modulus of 1000 MPa or more as measured in accordance with JIS K6734.   The manufacturing method according to claim 1, wherein the transparent surface protective layer contains an ionizing radiation curable resin as a resin component.   The base sheet contains a polyolefin resin as a resin component, according to any one of claims 1 to 6.

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