JP5332271B2 - Decorative sheet - Google Patents

Description

The present invention relates to a decorative sheet.

  Conventionally, a polyvinyl chloride resin sheet is frequently used as a constituent material of a resin-made decorative sheet. When the sheet is used, there are advantages such as excellent scratch resistance and easy embossing.

  However, polyvinyl chloride resin may release harmful black smoke and chlorinated gas during incineration. Therefore, in recent years, olefin-based resins have been used as resins that do not release chlorine-based gases during incineration, instead of polyvinyl chloride resins.

  For example, in a decorative sheet obtained by sequentially laminating a pattern layer, a transparent adhesive layer, a transparent resin layer, and a transparent surface protective layer on a base sheet, a polyolefin resin is used as the resin component of the transparent resin layer. Is used. In addition, various additives are contained in the transparent resin layer for the purpose of imparting various performances such as weather resistance and mechanical stain resistance to the decorative sheet.

  However, when the decorative sheet is folded, there is a problem that the vicinity of the fold is easily whitened. Whitening tends to occur when the transparent resin layer has a sea-island structure. Here, the sea-island structure refers to a state where crystals (islands) are scattered in an amorphous region (sea). When the transparent resin layer has a sea-island structure, an interface is formed between the amorphous region and the crystal. When the decorative sheet is bent, cracks and the like are generated from the interface, and the crystal structure of the polyolefin-based resin is destroyed, resulting in whitening. Moreover, when it contains an additive, the interface between the polyolefin resin and the additive causes whitening.

  For example, in Patent Document 1, in a decorative sheet having a transparent or translucent surface resin layer made of a polypropylene resin, the elasticity of the decorative sheet is improved by adding styrene butadiene rubber to the resin layer, and bending processing is performed. It has been reported that whitening can be prevented during

  However, in the technique of Patent Document 1, whitening cannot be sufficiently suppressed when a large amount of additive is contained in the surface resin layer.

Therefore, development of a decorative sheet that is less likely to be whitened when folded even when it contains a large amount of additives is eagerly desired.
JP 2006-281687 A

  The main object of the present invention is to provide a decorative sheet that is less likely to be whitened during bending even when it contains a large amount of additives.

  As a result of intensive studies, the present inventor has found that the above problems can be solved by including a specific component in the transparent resin layer, and has completed the present invention.

That is, the present invention relates to the following decorative sheet.
1. A decorative sheet having a transparent resin layer containing a polypropylene resin,
The transparent resin layer is (1) an α-olefin elastomer having a compression set at 70 ° C. of 60 % or less and (2) a melt flow rate value at 230 ° C. of 1 to 7 g / 10 min. contain,
The α-olefin elastomer is a polymer obtained by polymerizing an α-olefin having 2 to 20 carbon atoms using a metallocene catalyst,
The α-olefin is at least selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-butene, and 4-methyl-1-pentene. One kind of α-olefin having 2 to 20 carbon atoms,
The transparent resin layer further contains a moldability modifier that is low density polyethylene,
Makeup sheet.
2 . Item 2. The decorative sheet according to Item 1, wherein the transparent resin layer further contains an ultraviolet absorber.
3 . Item 3. The decorative sheet according to Item 1 or 2 , wherein the transparent resin layer further contains a light stabilizer.
4 . Item 4. The decorative sheet according to any one of Items 1 to 3 , wherein a pattern layer, a transparent adhesive layer, the transparent resin layer, and a transparent surface protective layer are sequentially laminated on the base material sheet.

The decorative sheet of the present invention is a decorative sheet having a transparent resin layer containing a polypropylene resin,
The transparent resin layer comprises: (1) an α-olefin elastomer having a compression set at 70 ° C. of 75% or less and (2) a melt flow rate value at 230 ° C. of 1 to 20 g / 10 min. contains.

  In the present invention, a crystal (island) having a sea-island structure can be effectively refined by including the α-olefin-based elastomer in a transparent resin layer containing a polypropylene-based resin as a resin component. Moreover, when the said transparent resin layer contains various additives in large quantities, the compatibility of the said additive with respect to the said polypropylene resin can be improved by containing the said alpha-olefin type elastomer. That is, the α-olefin-based elastomer can serve as a compatibilizing agent. By such refinement of the sea-island crystal and improved compatibility of the additive, whitening that occurs when the decorative sheet is folded is prevented or suppressed.

  The structure of the decorative sheet of the present invention is not particularly limited as long as the transparent resin layer is laminated on the base sheet (the front surface of the base sheet). For example, a decorative sheet formed by laminating a pattern layer, a transparent adhesive layer, the transparent resin layer, and a transparent surface protective layer in this order on a substrate sheet.

  Hereinafter, the decorative sheet of the present invention will be specifically described with the decorative sheet having such a configuration as a representative example.

The base sheet is preferably a film containing a polyolefin resin as a resin component.

  As said 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. These can be used alone or in combination of two or more. Among these, polyethylene, polypropylene, polyolefin-based thermoplastic elastomers and the like are particularly preferable.

  The polyolefin resin is preferably a homopolymer or a copolymer mainly composed of polypropylene. For example, a homopolypropylene resin, a random polypropylene resin, a block polypropylene resin, and a copolymer of a crystalline part of polypropylene and an α-olefin having 2 to 20 carbon atoms other than propylene can be given. 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 a block polymer using isotactic polypropylene as a hard segment and atactic polypropylene as a soft segment. In particular, an elastomer obtained by mixing a hard segment made of isotactic polypropylene and a soft segment made of atactic polypropylene at a weight ratio of 80:20 is preferable.

  A well-known 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). These can be used alone or in combination of two or more. About the compounding quantity of the said additive, it can set suitably according to a product characteristic.

  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. These can be used alone or in combination of two or more. 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 the adherend (base material to which the decorative sheet is bonded) 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.

  The base sheet is obtained by forming a resin composition containing the resin component or the like 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 material sheet is usually about 50 to 150 μm, preferably about 60 to 80 μm.

  Corona discharge treatment, ozone treatment, plasma treatment, ionizing radiation treatment, dichromic acid on the front and back surfaces (surface opposite to the surface on which the following pattern layer is laminated) as required Surface treatment such as treatment may be performed. For example, when the corona discharge treatment is performed, the surface tension of the substrate sheet surface may be 35 dyne or more, preferably 40 dyne or more. The surface treatment may be performed according to a conventional method for each treatment.

  You may provide a primer layer in the back surface of a base material sheet as needed.

  A primer layer can be formed by apply | coating a well-known primer agent to the back surface of a base material sheet. As the primer agent, for example, an acrylic-urethane resin-based primer agent made of an acrylic-modified urethane resin or the like is preferable in terms of weather resistance.

The application amount of the primer agent is usually about 0.1 to 10 g / m ² , preferably about 0.1 to 5 g / m ² .

  The thickness of the primer layer is usually about 0.01 to 10 μm, preferably about 0.1 to 5 μm.

A pattern layer is formed on the pattern pattern layer base sheet (front surface).

  The design pattern layer imparts design properties with a desired design to the decorative sheet, and the type of the design is not 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 colorants include inorganic pigments such as carbon black, titanium white, zinc white, dial, bitumen, 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 resins, styrene resins, polyester resins, urethane resins, acrylic-urethane resins, chlorinated polyolefin resins, vinyl chloride-vinyl acetate copolymer resins, polyvinyl butyral resins. Alkyd resins, petroleum resins, ketone resins, epoxy resins, melamine resins, fluorine resins, silicone resins, fiber derivatives, rubber resins, 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.

  The thickness of the pattern layer can be appropriately set according to the product characteristics. Usually, the layer thickness during coating is about 1 to 15 μm, and the layer thickness after drying is about 0.1 to 10 μm.

A colored concealment layer may be further formed between the colored concealment layer base sheet and the pattern layer, if necessary. The colored masking layer is provided when it is desired to mask the ground color of the adherend (base) 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. This 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 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. These can be used alone or in combination of two or more.

  As a method for forming a transparent adhesive layer, for example, an adhesive is applied on the following transparent resin layer, dried and cured to form a transparent adhesive layer, and then the obtained laminate is used as the laminate. The method of laminating | stacking on the said pattern pattern layer by the dry laminating method is mentioned so that a pattern pattern layer and this transparent adhesive layer may contact | connect.

  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. 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 dry laminating method may follow a known method.

  The thickness of the transparent adhesive layer is usually about 0.1 to 30 μm, preferably about 1 to 20 μm after drying.

Transparent resin layer The transparent resin layer is formed on the transparent adhesive layer. The transparent resin layer is not particularly limited as long as it is transparent, and includes any of colorless and transparent, colored and transparent, and translucent.

  The transparent resin layer contains a polypropylene resin as a resin component.

Examples of the polypropylene resin include random polypropylene copolymers and homopolypropylene. These can be used alone or in combination of two or more.
The random polypropylene copolymer means a copolymer obtained by randomly copolymerizing propylene and a monomer other than propylene.

  Examples of the monomer other than propylene include ethylene and 1-butene. These monomer components are contained alone or in combination of two or more.

  The copolymerization ratio of propylene and the monomer may be appropriately set according to the type of the monomer, etc. For example, when the monomer is ethylene, the copolymerization ratio of propylene and ethylene is 99 to 94: 1. ~ 6 is preferred.

  The transparent resin layer has (1) a compression set at 70 ° C. of 75% or less, preferably 20 to 65%, and (2) a melt flow rate value (MFR) at 230 ° C. of 1 to 20 g / It contains an α-olefin elastomer that is 10 minutes, preferably 5 to 15 g / 10 minutes. By containing the α-olefin elastomer, whitening when the decorative sheet is folded can be prevented or suppressed.

The compression set can be calculated by the following method. First, six sheets of α-olefin elastomer having a thickness of 2 mm are prepared using a press molding machine. Next, the following processes 1) to 4) are sequentially performed on a laminate (thickness 12 mm) obtained by stacking six sheets according to JIS K6262.
1) 25% compression with spacer 2) Leave in a constant temperature room (23 ° C) for 24 hours
3) Heat treatment at 70 ° C. for 24 hours
4) Leave in a constant temperature room (23 ° C.) for 30 minutes. Then, the thickness of the obtained processed product is measured, and the compression set is calculated according to the following formula.

[ (Thickness of the laminate−Thickness of the treated product) ÷ ( Thickness of the laminate−Thickness of the spacer)] × 100
The MFR can be measured by a test method described in JIS K 7210 (Thermoplastic flow test method). As test conditions, “230 ° C., 21.18 N (2.16 kgf)” described in JIS K 6760 is adopted.

  The α-olefin-based elastomer is preferably an elastomer in which a crystalline part and an amorphous part are controlled in nano order. By using such an elastomer, impact resistance and scratch resistance can be imparted to a decorative sheet without impairing transparency even when mixed with the polypropylene resin.

The α-olefin-based elastomer preferably has a softening temperature (TMA) of 120 to 150 ° C. of a planar indenter having a diameter of 1.8 mmφ under a load of 2 kg / cm ² . In addition, the said diameter is a diameter of the front end surface of a planar indenter.

  As the α-olefin elastomer, for example, a polymer obtained by polymerizing an α-olefin having 2 to 20 carbon atoms using a metallocene catalyst can be used.

  Examples of the α-olefin include 2 to 20 carbon atoms such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-butene and 4-methyl-1-pentene. Can be mentioned.

  In the polymerization, monomer components other than the α-olefin may be further polymerized within a range not impeding the effects of the present invention.

  A commercially available product can be used as the α-olefin elastomer.

  The content of the α-olefin elastomer in the transparent resin layer is preferably 5 to 100 parts by weight and more preferably 5 to 43 parts by weight with respect to 100 parts by weight of the polypropylene resin. When the content of the α-olefin elastomer is 5 to 100 parts by weight with respect to 100 parts by weight of the polypropylene resin, whitening when the decorative sheet is folded can be more reliably prevented. In particular, when the transparent resin layer contains a hindered amine light stabilizer and / or low density polyethylene of a side chain bond type polymer, there is a problem that the bending processability of the decorative sheet is lowered and whitening is likely to occur. However, if the content of the α-olefin-based elastomer is within the above range, the above problem can be suitably solved.

  The transparent resin layer preferably further contains an ultraviolet absorber. By including the ultraviolet absorber, excellent weather resistance can be imparted to the decorative sheet.

  Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, and a triazine ultraviolet absorber. These can be used individually by 1 type or in combination of 2 or more types. In particular, it is preferable to use a triazine-based ultraviolet absorber in that it can provide excellent weather resistance.

  Moreover, it is preferable that the said ultraviolet absorber is liquid. By using a liquid ultraviolet absorbent, even when a large quantity of ultraviolet absorbent is used, the occurrence of bleeding (generation of needle crystals) can be suppressed.

  A commercial item can be used as said ultraviolet absorber.

  The transparent resin layer preferably further contains a light stabilizer. By including a light stabilizer, excellent weather resistance can be imparted to the decorative sheet.

  As the light stabilizer, a known light stabilizer can be used, and it is particularly preferable to use a side chain-bonded polymer hindered amine light stabilizer. By using the hindered amine light stabilizer, a decorative sheet having excellent weather resistance can be obtained. In addition, it is less susceptible to mechanical contamination, and production efficiency is improved.

  The transparent resin layer preferably further contains a moldability modifier. By including a moldability modifier, the high-speed sheeting suitability of the transparent resin layer is improved.

  As the moldability modifier, low density polyethylene is particularly preferable.

  In addition, you may further contain a well-known additive as needed. Examples of the additive include a filler, a flame retardant, a lubricant, and an antioxidant.

  In the present invention, by including the α-olefin elastomer in the transparent resin layer, the compatibility of the additive with respect to the polypropylene resin can be improved, so that it has excellent performance such as weather resistance, and A decorative sheet in which whitening at the time of bending is prevented or suppressed can be suitably obtained.

  As a method for forming the transparent resin layer, for example, a method of laminating a resin composition containing the resin component or the like on the transparent adhesive layer by, for example, a calendar method, an inflation method, a T-die extrusion method, or the like. Is mentioned.

  The thickness of the transparent resin layer is usually about 10 to 250 μm, preferably about 30 to 100 μm.

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

  Moreover, you may provide a primer layer on the surface as needed.

  The primer layer can be formed by applying a known primer agent to the surface of the transparent resin layer. As the primer agent, those exemplified above can be used.

The application amount of the primer agent is not particularly limited, but is usually 0.1 to 10 g / m ² , preferably about 0.1 to 5 g / m ² .

  Although the thickness of a primer layer is not specifically limited, Usually, 0.01-10 micrometers, Preferably it is about 0.1-5 micrometers.

  A wiping process may be applied to the surface of the transparent resin layer for the purpose of improving designability and weather resistance.

  As a method of performing the wiping process, for example, a method of forming a concave portion on the surface of the transparent resin layer by embossing and filling the concave portion with a colored ink composition can be mentioned.

  For example, embossing is performed by using an embossed plate provided with an uneven pattern of a desired shape by heating and softening the resin constituting the transparent resin layer on a heating drum and further heating to 140 to 180 ° C. with an infrared radiation heater. Pressurized, shaped, cooled and fixed. For this, a known single wafer or rotary embossing machine may be used. The embossing may be performed simultaneously in the step of laminating the transparent resin layer on the transparent adhesive layer.

  Examples of the concavo-convex pattern include a wood grain conduit groove, a float pattern (a concavo-convex pattern of a raised annual ring), a hairline, a grain, and a satin texture.

  As said coloring ink composition, the composition conventionally used for the wiping process can be used. Examples thereof include a colored ink composition containing a binder, a colorant, silica particles, an ultraviolet absorber, a light stabilizer, and the like.

Transparent surface protective layer A transparent surface protective layer is formed on the transparent resin layer.

  Examples of the surface protective layer include a surface protective layer made of an ionizing radiation curable resin. By forming a surface protective layer made of an ionizing radiation curable resin, the abrasion resistance, impact resistance, stain resistance, scratch resistance, weather resistance, etc. of the decorative sheet can be improved.

  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.

  In particular, as the ionizing radiation curable resin, a prepolymer having a radical polymerizable unsaturated group is preferable, and urethane acrylate is more preferable.

  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 transparent surface protective layer is formed by, for example, applying an ionizing radiation curable resin on the transparent resin layer (or the primer layer) by a known coating method such as gravure coating or roll coating, and then irradiating with ionizing radiation. It can be formed by curing the resin.

  The transparent surface protective layer may further contain a known additive as required. Examples of the additive include an ultraviolet absorber, the light stabilizer, a filler, a matting agent, a flame retardant, a lubricant, and an antioxidant.

  The thickness of the transparent 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.

Embossing An embossed pattern may be applied to the front surface of the decorative sheet of the present invention as necessary. The embossed pattern can be applied by, for example, a known embossing roll. For example, a desired embossed pattern can be formed by pressing from 100 to 180 ° C. from the transparent surface protective layer side using an embossing roll. Embossed patterns include wood grain plate conduit grooves, stone plate surface irregularities, cloth surface textures, satin texture, sand texture, hair lines, and multi-line grooves.

  The decorative sheet of the present invention can be suitably used particularly as a decorative sheet for floors.

  This invention can prevent or suppress the whitening which arises when a decorative sheet is bent by making the transparent resin layer containing a polypropylene resin as a resin component contain the α-olefin elastomer.

  In particular, the decorative sheet of the present invention can effectively prevent the whitening even when the transparent resin layer contains a large amount of various additives.

  Therefore, according to the present invention, various properties such as weather resistance, impact resistance, and scratch resistance can be suitably imparted to the decorative sheet while preventing or suppressing whitening that occurs when the sheet is bent.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to the examples.

Reference Examples 1-5, Examples 6-8, and Comparative Examples 1-4
A decorative sheet having the structure shown in FIG. 1 was produced by the following method.

  As the substrate 2, a resin sheet made of a colored polypropylene resin (thickness 80 μm) was prepared. After performing corona discharge treatment on the front surface and the back surface, a wood grain pattern was formed on the surface by gravure printing to obtain a picture pattern layer 3. On the other hand, a back primer layer 7 (thickness: 2 μm) using urethane resin as a binder was formed on the back surface by gravure printing.

  Next, a transparent resin layer 4 (thickness 80 μm) obtained by melting a resin composition containing random polypropylene as a resin component at 230 ° C. using a T-die is formed, and 2 on the transparent resin layer 4 A coating solution made of a liquid curable urethane resin is applied to form a transparent adhesive layer 8 (thickness 15 μm in a dry state), and the adhesive layer side is laminated on the pattern layer 3 by a dry laminating method. I let you. The resin composition for forming the transparent resin layer 4 contained the elastomers shown in Table 1 and ultraviolet absorbers in the proportions shown in Table 1.

  Next, a primer layer 5 was formed on the transparent resin layer 4. First, urethane acrylic with a urethane component to acrylic component mass ratio of 7/3 as a binder, trade name “Tinuvin 400” (manufactured by Ciba Specialty Chemicals) as a UV absorber, trade name “hindered amine light stabilizer” A resin composition containing 2% by mass of Tinuvin 123 ”(manufactured by Ciba Specialty Chemicals) was prepared.

This resin composition and hexanemethylene diisocyanate (curing agent) were mixed at a mass ratio of 100 to 5, and the mixture was applied onto the transparent resin layer 4 to form a primer layer 5. The application amount of the mixture was 2.5 g / m ² . The thickness of the primer layer 5 was about 2 μm.

On the primer layer 5, an ionizing radiation-polymerizable oligomer comprising 80% by weight of a bifunctional urethane acrylate oligomer (A) and 20% by weight of a hexafunctional urethane acrylate oligomer (B) has a solid content of 5 g / m ² by roll coating. Coating and drying were performed to form an uncured electron beam curable resin layer.

  The bifunctional urethane acrylate oligomer is formed by bonding a) isophorone diisocyanate, b) polyester diol (condensation product of adipic acid and ethylene glycol) and c) 2-hydroxyethyl acrylate, and has a weight average. The molecular weight is 1700.

  As the hexafunctional urethane acrylate oligomer, product name “UA306H” manufactured by Kyoeisha Chemical Co., Ltd. was used.

  After forming an uncured electron beam curable resin layer, in an environment with an oxygen concentration of 200 ppm, the uncured resin layer is irradiated with an electron beam under conditions of an acceleration voltage of 125 KeV and 5 Mrad to cure the resin to obtain a 15 μm thick A line curable resin layer (transparent surface protective layer 6) was formed.

  A decorative sheet was prepared by the above process.

Test example 1 (0 ° C steel sheet bending test)
A steel sheet coated with an adhesive composed of a two-component curable urethane resin was cured in an oven at 150 ° C. for about 1 minute, and then immediately laminated with the decorative sheet of Reference Example 1 and the steel sheet using a roll laminator. .

  The obtained sheet steel sheet was subjected to a bending test according to the V-block method defined in JIS Z 2248 6.3 under the conditions of a sheet steel sheet surface temperature of 0 ° C., a bending angle of 90 °, and a bending inner radius of 0 mm. .

The same test was performed on the decorative sheets of Reference Examples 2 to 5, Examples 6 to 8, and Comparative Examples 1 to 4.

  After the bending test, the case where the vicinity of the crease was not whitened was evaluated as ○, the case where slight whitening was observed in the vicinity of the fold, but the design was not problematic, Δ, and the case where the vicinity of the fold was whitened was evaluated as ×.

Test Example 2 (High-speed sheeting suitability)
The resin compositions for forming the transparent resin layers of Reference Examples 1 to 5, Examples 6 to 8 and Comparative Examples 1 to 4 were each extruded at a constant amount at 230 ° C. using a T-die extruder, and the thickness was 80 μm. The transparent resin layer was prepared and the operation of winding it was continuously performed. The change in the width of the transparent resin layer was confirmed when the winding speed was changed from low speed to high speed.

  When wound at high speed, compared to when wound at low speed, the width of the transparent resin layer is almost the same, and the width of the transparent resin layer wound at high speed is constant. When evaluated and wound at high speed, the width of the transparent resin layer is smaller than when wound at low speed, and the width of the transparent resin layer wound at high speed is not constant (the width is extremely The case where a small part and a part having a small width are mixed is evaluated as “low speed”.

  The results are shown in Table 2.

Test example 3 (pencil hardness)
The pencil hardness of the produced floor decorative material was measured using a pencil hardness tester. The test was conducted in accordance with JIS K 5600-5-4 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.

Reference Example 1-5 is a schematic view showing a cross section of the decorative sheets prepared in Examples 6-8 and Comparative Examples 1-4.

Explanation of symbols

1. Cosmetic sheet
2.Base material
3. Pattern pattern layer
3a. Pattern layer
3b. Colored layer.
4.Transparent resin layer
5.Primer layer
6.Transparent surface protective layer
7.Back primer layer
8.Transparent adhesive layer

Claims (4)

A decorative sheet having a transparent resin layer containing a polypropylene resin,
The transparent resin layer is (1) an α-olefin elastomer having a compression set at 70 ° C. of 60 % or less and (2) a melt flow rate value at 230 ° C. of 1 to 7 g / 10 min. contain,
The α-olefin elastomer is a polymer obtained by polymerizing an α-olefin having 2 to 20 carbon atoms using a metallocene catalyst,
The α-olefin is at least selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-butene, and 4-methyl-1-pentene. One kind of α-olefin having 2 to 20 carbon atoms,
The transparent resin layer further contains a moldability modifier that is low density polyethylene,
Makeup sheet. The decorative sheet according to claim 1, wherein the transparent resin layer further contains an ultraviolet absorber. The decorative sheet according to claim 1 or 2 , wherein the transparent resin layer further contains a light stabilizer. The decorative sheet according to any one of claims 1 to 3 , wherein a pattern layer, a transparent adhesive layer, the transparent resin layer, and a transparent surface protective layer are sequentially laminated on a base sheet.

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