JP5521886B2 - Mirror surface decorative sheet - Google Patents

Description

  The present invention relates to a mirror-type decorative sheet used by adhering to a base material for a decorative material such as a wooden base material, an inorganic base material, a synthetic resin base material, a metal base material, and the like, particularly a kitchen door and a bathroom interior. It is related with the mirror surface decorative sheet used for decorative materials, such as.

  Conventionally, as a decorative sheet used for a decorative board, a sheet made of a polyvinyl chloride resin has been most common. In recent years, however, polyvinyl chloride resin has become a cause of the generation of hydrogen chloride gas and dioxin, a highly toxic substance, which causes acid rain during incineration, and further due to the bleed-out of plasticizer added to the sheet made of polyvinyl chloride resin. There are also problems such as deterioration in designability, and it has been regarded as a problem from the viewpoint of environmental protection. From the background as described above, a decorative sheet using a non-vinyl chloride resin has been demanded.

  Under such circumstances, decorative sheets using resins such as polyethylene, polypropylene, polyethylene terephthalate, and acrylic as a substitute for vinyl chloride resin have been proposed and are now on the market.

  Among these, a decorative sheet using polypropylene provided with moderate flexibility, abrasion resistance, scratch resistance, heat resistance, chemical resistance, post-processability, etc. required for a decorative sheet, and provided at low cost, Most specifications have been proposed and are in actual use.

  However, the use of cosmetic materials such as kitchen doors and bathroom interiors requires a very high-definition image with a mirror-finished surface compared to other normal cosmetic materials. Certain polypropylenes are not necessarily suitable for this application due to their high internal haze. The decorative sheet using acrylic resin can reduce the internal haze because it does not have a crystal structure. However, it is particularly important for kitchen applications, in terms of contamination and chemicals, compared to a decorative sheet using polypropylene resin. Inferior.

  Therefore, as a decorative sheet for uses requiring high definition, a mirror-type decorative sheet having a structure in which a polyester resin film having excellent transparency, surface smoothness, scratch resistance, and the like is arranged on the surface is mainly used. It is used. Specifically, transparent polyethylene terephthalate in which an appropriate pattern is printed on the back side of the surface of a concealable base material sheet made of a colored polyvinyl chloride resin film or a colored polyolefin resin film via an adhesive. A resin film is laminated. In particular, when a polyethylene terephthalate resin that has been subjected to stretching treatment is used, a decorative sheet excellent in stain resistance and chemical resistance can be obtained.

However, the polyethylene terephthalate resin that has been subjected to stretching treatment is not suitable for applications such as bonding to a substrate having a complicated shape using a wrapping method because it has a high so-called “stiffness” and lacks flexibility. Further, since it is necessary to draw a polyethylene terephthalate resin in advance to prepare a film, it is impossible to manufacture a decorative sheet using an extrusion lamination method with high production efficiency, which tends to increase the manufacturing cost. In addition, when used for so-called water applications such as for kitchens and bathrooms, there is also a problem of deterioration with time due to hydrolysis of the polyester resin.

Japanese Patent No. 2833484 Japanese Patent No. 3175482 Japanese Patent No. 3271102 JP 7-17005 A Japanese Patent No. 3641946

  The present invention has been made in order to solve the above problems from such a background, and the problem is that it has contamination resistance and chemical resistance, and has high production efficiency such as an extrusion lamination method. To provide a mirror surface decorative sheet that can select an extrusion laminating method and has no concern about hydrolysis, and at the same time has both high definition and flexibility, and can withstand long-term use. .

The present invention solves the above-mentioned problems, that is, the invention according to claim 1 is a mirror-finished decorative sheet having a pattern layer and a transparent olefin resin layer in this order on a base sheet. The olefin resin layer includes (1) a copolymer composed of two or more olefins comprising propylene as a main raw material and ethylene and / or an α-olefin other than propylene having 3 to 20 carbon atoms, (2) A copolymer composed of two or more olefins has a Shore A hardness of 65 to 90 according to the compliance standard ASTM D2240, a density of 860 to 875 kg / m ³ according to the compliance standard ASTM D1505, and a glass transition temperature of −35 to −− according to differential scanning calorimetry. 25 ° C. and melting point of 130 to 170 ° C. (3) The copolymer has a network structure crystal, A mirror surface decorative sheet characterized in that a crystal lamella has a folded structure of 100 nm or less.

  The invention according to claim 2 is characterized in that, in 100% by weight of the transparent olefin resin, two or more olefins comprising propylene as a main raw material and ethylene and / or an α-olefin other than propylene having 3 to 20 carbon atoms. The mirror surface decorative sheet according to claim 1, comprising 50% by weight or less of a random polypropylene resin obtained by random copolymerization.

  The invention according to claim 3 is the specular decorative sheet according to any one of claims 1 to 2, further comprising a hard coat surface protective layer that is three-dimensionally crosslinked on the outermost surface.

  The invention according to claim 4 is characterized in that a weather resistance stabilizer is added to at least one of the transparent olefin resin layer and the hard coat surface protective layer. The mirror surface decorative sheet according to any one of the above.

  The invention according to claim 5 is the specular decorative sheet according to claim 4, wherein the weather stabilizer has a molecular weight of 400 or more.

  According to the first aspect of the present invention, a specular decorative sheet having both high definition and flexibility can be obtained. This is a component in the transparent olefin resin layer, the crystal takes a network structure without taking a spherulite structure, and transparency is ensured by taking a folded structure with a crystal lamella of 100 nm or less, and at the same time, It is a copolymer composed of propylene and ethylene or an α-olefin other than propylene having 3 to 20 carbon atoms, and flexibility is also added when the Shore A hardness is in the range of 65 to 90. At the same time, since it has the same melting point and glass transition point as ordinary polypropylene resin, it has heat resistance, chemical resistance, and contamination resistance comparable to those of ordinary polypropylene resin decorative sheets.

When the crystal has a spherulite structure or the lamellar size exceeds 100 nm, the internal haze value increases due to the relationship between light refraction and irregular reflection, and high-definition like the mirror-finished decorative sheet of the present invention is obtained. It is not possible.
In addition, when the copolymer is not a copolymer composed of propylene and ethylene or an α-olefin other than propylene having 3 to 20 carbon atoms, the rigidity becomes high and the Shore A hardness exceeds the upper limit of 65 to 90, which is rich in flexibility. Can't get a mirror-finished decorative sheet.
When the Shore A hardness is less than 65, the crystal network structure cannot sufficiently exhibit heat resistance, chemical resistance, contamination resistance, and the like, and the stickiness of the transparent olefin resin layer increases, blocking, Concerns about defects such as bleed-out of additive components increase.

  Further, according to the invention described in claim 2, it is possible to enhance the scratch resistance of the mirror surface decorative sheet while maintaining a practically sufficient high definition and flexibility. If the proportion of the random copolymer exceeds 50% by weight, or if the random copolymer is replaced with a homopolypropylene, the internal haze value rises because the crystals begin to take a spherulitic structure, and the transparent The nature becomes low. When a block copolymer is used instead of the random copolymer, the internal haze value is increased due to the sea-island structure of the block, and the transparency is lowered.

  Further, the invention according to claim 3 makes it possible to further improve the scratch resistance of the mirror surface decorative sheet. The hard coat surface protective layer is more preferably three-dimensionally cross-linked from the viewpoint of heat resistance, chemical resistance, stain resistance, and the like. As a three-dimensional crosslinking method, a one-component thermosetting type, a two-component thermosetting type, an ultraviolet ray curable type, an electron beam curable type, or the like is generally used, but the method is not limited to these, and required performance, etc. The cross-linking method may be appropriately selected according to the conditions. The material of the hard coat surface protective layer is not particularly limited, but it is preferable to use an acrylic coating agent in consideration of balance with transparency, weather resistance, scratch resistance and the like.

  In addition, according to the invention described in claim 4, the weather resistance performance of the mirror surface decorative sheet can be greatly improved. Examples of the weathering stabilizer include an ultraviolet absorber, a light stabilizer, and an antioxidant. The most desirable thing is to put an appropriate amount of UV absorber and light stabilizer in both the hard coat surface protective layer and the transparent olefin resin layer, but since UV rays fall from the outermost surface, it is added only to the hard coat surface protective layer. But the effect is great. Conversely, the addition of the UV absorber to the transparent olefin resin layer is not necessarily required as long as a sufficient UV absorber is added to the hard coat surface protective layer, and only the light stabilizer may be added. In some cases. However, it is preferable to use an ultraviolet absorber and a light stabilizer in combination because each of them exhibits a synergistic effect and contributes to improvement in weather resistance.

  Further, according to the invention described in claim 5, it is possible to suppress the bleed out of the weather stabilizer and improve the weather resistance. When a weathering stabilizer having a molecular weight of 400 or less is used, bleed out with time increases. When a weathering stabilizer having a large molecular weight is used, when the addition amount is set by weight ratio, the absorptivity is reduced as compared with the case of adding a weathering stabilizer having a small molecular weight. Therefore, the addition amount may be increased, but an influence such as an increase in the internal haze value is produced, and therefore, the adjustment may be appropriately made. Specifically, the range of 1 to 20% by weight in the hard coat surface protective layer and the range of 0.1 to 5% by weight in the transparent olefin resin layer are suitable.

It is explanatory drawing which shows the structure of the cross section of one Example of the mirror surface decorative sheet of this invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows a cross-sectional structure of an embodiment of a mirror-finished decorative sheet of the present invention, but the specification is not limited to this as long as it is within the scope of the claims of the present invention. As a layer structure, the pattern layer 2, the adhesive layer 3 provided as appropriate, the transparent olefin resin layer 4, and the hard coat surface protective layer 5 provided as appropriate are laminated on the base sheet 1 in this order.

  As the base sheet 1 in the present invention, polypropylene, polyethylene, ethylene vinyl acetate copolymer resin, ethylene vinyl alcohol copolymer resin, polystyrene, ABS, polymethyl methacrylate, polymethyl acrylate, polybutyl acrylate, polyvinyl acetate Specific examples include sheets made of non-vinyl chloride resin materials such as polyvinyl alcohol, polyvinyl butyral, polyvinyl acetal, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyurethane, polyamide, nylon 6 and nylon 66. Can be mentioned. Among these, considering recyclability, a base sheet made of a polyolefin material such as polypropylene or polyethylene is desirable. Furthermore, if the base sheet is made of a polypropylene material, most of the components of the decorative sheet are made of a polypropylene material. Therefore, although it is still desirable, it is not necessarily limited to this.

  Moreover, it is possible to add 1 type, or 2 or more types of additives, such as an inorganic pigment, antioxidant, a light stabilizer, and an antiblocking agent, in the said resin which comprises the base material sheet 1 in an appropriate quantity. is there.

  The inorganic pigment is added to conceal the base sheet 1. The reason for concealing is to prevent the base material such as a wooden board, an inorganic board, or a metal plate to be bonded from being visible from the surface of the mirror surface decorative sheet. However, this is not the case when it is desired to make use of the texture of the base material.

  Further, when the T-die extrusion method is used as a method for producing the base sheet 1, a synthetic resin material for forming the film is directly colored with a concealing colorant such as a dye or a pigment and heated and melted. The substrate sheet 1 obtained by extrusion from the T die may be colored to impart concealability.

  In this case, the coloring method of the base sheet 1 in the T-die extrusion method includes a dry color method and a master batch method, but is not particularly limited. In the dry color method, a fine powdery colorant obtained by treating a pigment with a dispersion aid or a surfactant is directly mixed into an ordinary uncolored synthetic resin material for forming the base sheet 1. This is a method of coloring. On the other hand, in the master batch method, a master batch pellet in which a normal synthetic resin material that is not colored for forming the base sheet 1 and a high concentration pigment is melt-kneaded and pre-dispersed is prepared in advance. In the extrusion hopper, this master batch pellet is dry blended with a normal uncolored synthetic resin material for forming the base sheet 1 into a film.

  The types of pigments used for coloring may be those usually used, but inorganic pigments such as titanium oxide, ultramarine, cadmium pigment, iron oxide and the like are particularly desirable in consideration of heat resistance and weather resistance. Also, organic pigments such as phthalocyanine pigments and quinacridone pigments can be used. The pigment-to-resin ratio and hue are appropriately determined in view of the degree of concealment and design properties, and are not particularly limited.

  The pattern layer 2 in the present invention is generally provided on the base sheet 1 using a known printing ink by a known printing method such as gravure printing, intaglio printing, flexographic printing, silk printing, electrostatic printing, and inkjet printing. However, this is not necessarily the case. Also, the ink used in this case is a known ink, that is, a colorant such as a dye or pigment, an extender pigment, pearl, etc. are added to the vehicle, and further, a plasticizer, a stabilizer, a wax, a grease, a desiccant, a curing agent, an increase agent. The ink may be an ink obtained by arbitrarily adding a viscosity agent, a dispersant, a filler, and the like and kneading the mixture sufficiently with a solvent, a diluent, or the like. Further, as a method for laminating the pattern layer 2, a method such as a vapor deposition method, a spray method, a die coating method, a dipping coating method, or a transfer method may be used instead of providing a printing ink using a known printing method. Or you may laminate | stack metal thin films, such as aluminum foil, copper foil, gold foil, and silver foil, via an adhesive agent.

  In the mirror surface decorative sheet of the present invention, a primer coat layer (not shown) laminated on the back surface of the base material sheet 1 is also suitably used as needed in order to increase the adhesion to various base materials.

  The adhesive layer 3 provided as appropriate is appropriately selected and provided in order to improve the interlayer adhesion between the base sheet 1 provided with the pattern layer 2 and the transparent olefin resin layer 4 to be described later. It can be provided using a known method such as a coating method.

  As the transparent olefin resin layer 4 in the present invention, a desired performance can be obtained by using a material having the characteristics of the present invention. Among them, random polypropylene composed mainly of propylene in the transparent olefin resin layer and composed of ethylene and / or an α-olefin other than propylene having 3 to 20 carbon atoms is a random copolymer polypropylene resin composed of two types of olefin materials. However, there is no problem even if it is a random copolymer polypropylene resin made of three or more olefin materials. In addition, the ratio of ethylene and / or α-olefin other than propylene having 3 to 20 carbon atoms to propylene is not limited in the present invention, but in order to ensure the properties as polypropylene, it is 10 in monomer units. % Or less, more desirably 7% or less.

  The melt viscosity value of the transparent olefin resin layer 4 at the time of melting is preferably in the range of 0.1 to 50 g / 10 min in terms of melt flow rate (MFR). If the MFR is less than 0.1 g / 10 min, molding is difficult, and if it exceeds 50 g / 10 min, the molecular weight is too small, resulting in insufficient mechanical properties. In order to obtain a better balance between moldability and mechanical properties, the MFR is more preferably in the range of 0.2 to 30 g / 10 min. When the transparent olefin resin layer 4 is a mixed system of two or more transparent olefin resins, each component does not have to be in the range of 0.1 to 50 g / 10 min in terms of melt flow rate (MFR), When the transparent olefin resin layer 4 is formed by an extrusion film forming method, the melt flow rate (MFR) of each other is preferably close to each other in order to improve the film forming stability.

The copolymer in the present invention has a Shore A hardness of 65 to 90 according to the compliance standard ASTM D2240, a density of 860 to 875 kg / m ³ according to the compliance standard ASTM-D1505, and a glass transition temperature of −35 to −25 by differential scanning calorimetry. Those having a melting point of 130 to 170 ° C. are used.

  Examples of the α-olefin other than propylene having 3 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene and 1-tetradecene. 1-hexadecene, 1-octadecene, 1-eicosene and the like.

  The Shore A hardness used in the present invention is a press molding condition of a temperature of 190 ° C., a heating and pressing time of 7 minutes, and cooling with a 15 ° C. chiller. After placement, a rubber hardness tester (Shore A type) was used to superimpose two sheets, and the scale was read immediately after contact with the pressing needle (according to ASTM-D2240). The Shore A hardness (ASTM-D2240) of the copolymer (B) composed of propylene and ethylene or an α-olefin other than propylene having 3 to 20 carbon atoms in the present invention is preferably 65 to 85, and more preferably 72 to Those in the range of 85 are preferred.

  The melting point and glass transition point used in the present invention are about 10 mg of a sample packed in an aluminum pan, (i) heated up to 200 ° C. at 100 ° C./min and held at 200 ° C. for 5 minutes (ii) 10 ° C. It is obtained by measuring the temperature of the endothermic peak observed in (iii) when the temperature is lowered to -70 ° C./min and then (iii) the temperature is raised to 200 ° C. at 10 ° C./min. When the temperature is raised in (iii), the temperature indicated by the first endothermic peak that is visible corresponds to the glass transition point, and the second endothermic peak that is visible is the melting point. In the present invention, a copolymer composed of propylene and ethylene or an α-olefin other than propylene having 3 to 20 carbon atoms has a melting point in the range of 130 to 170 ° C, more preferably 130 to 150 ° C. . It is desirable that the glass transition temperature measured by differential scanning calorimetry (DSC) is in the range of -35 ° C to -25 ° C.

The density used in the present invention is measured by a method based on ASTM-D1505 after a 2 mmt press sheet obtained under the same press molding conditions as the Shore A hardness measurement sample is allowed to stand at 23 ° C. for 72 hours. Is obtained. The density of the copolymer (B) consisting of propylene and ethylene or α-olefin other than propylene having 3 to 20 carbon atoms in the present invention is in the range of 860 to 875 kg / m ³ , and further 860 to 872 kg. / M ³ is preferred.

  As described above, the copolymer composed of propylene according to the present invention and ethylene or α-olefin other than propylene having 3 to 20 carbon atoms is not particularly limited as long as it satisfies the above physical properties, but is commercially available. It may be used. Examples thereof include “Notio” manufactured by Mitsui Chemicals, Inc. and “Tough Selenium” manufactured by Sumitomo Chemical Co., Ltd.

  The method for laminating the transparent olefin resin layer 4 in the present invention may be performed using a known method, and is not particularly limited, but is not limited to dry lamination method, wet lamination method, sand lamination method, extrusion lamination method ( A coextrusion laminating method) is preferably used. The film formation and bonding of the transparent olefin resin layer 4 may be performed in-line at one time, or may be performed after film formation and then bonded again.

  In the present invention, a concave embossed pattern may be appropriately provided on the surface of the transparent olefin resin layer 4. As the method, the transparent olefin resin layer 4 formed by melt extrusion and biaxial stretching from a T-die extruder is bonded through the adhesive layer 3. After the adhesive is cured by aging, a concave embossed pattern is applied to the surface layer using a heat drum having a pattern in which the concaves and convexes are reversed from the concave pattern to be applied. Such a method is known.

  The hard coat surface protective layer 5 provided as appropriate can be provided by laminating the outermost surface using a technique such as a gravure printing method after providing the concave embossed pattern. For the purpose of increasing the adhesion at the laminated interface, it is also necessary to introduce a polar group into the laminated interface by a known technique such as corona treatment. In particular, a transparent olefin resin which is basically a nonpolar resin is used. When using, polar group introduction | transduction by corona treatment etc. is performed suitably.

  Note that the application of the concave embossed pattern and the lamination of the hard coat surface protective layer 5 can be reversed in order. In that case, since the hard coat surface protective layer 5 firmly enters the recessed portion, the ability to maintain the weather resistance of the recessed portion is exhibited, and further improvement of the weather resistance can be expected. The substrate sheet 1 may be transparent, but a colored sheet to which a pigment or the like is added may be used so as not to show the texture of the substrate such as a steel plate to be bonded.

  As a material used for the hard coat surface protective layer 5 provided as appropriate, specifically, a resin is prepared by reacting a prepolymer in which a hydroxyl group is introduced into an acrylic resin or an ester resin with a separately prepared curing agent having an isocyanate group. It is good to make it harden by generating a urethane reaction thing inside. As the isocyanate component, an aromatic component may be used if importance is attached to immediate curing, and an aliphatic component may be used if importance is placed on ultraviolet resistance. In addition, when it is desired to impart flexibility to the hard coat surface protective layer 5, a method of modifying the urethane from a prepolymer state is also preferably used.

  As a method of curing the hard coat surface protective layer 5, in addition to a method of reacting with isocyanate (isocyanate curing method), a method of irradiating ultraviolet rays after adding a photopolymerization initiator (ultraviolet curing method), irradiating with an electron beam A method (electron beam curing method) or the like may be used. A plurality of these curing methods may be combined.

  The hard coat surface protective layer 5 generally uses various weathering stabilizers. For example, benzotriazoles, benzoates, benzophenones, hydroxyphenyltriazines, etc. are suitably used as UV absorbers, and hindered amines are preferably used as light stabilizers, and these are used alone or in combination. . Moreover, gloss can be adjusted by adding finely pulverized silica, and scratch resistance can be improved by adding glass-based beads. It is also preferable to add a slip agent to prevent sheet blocking or to add an antistatic agent to suppress adhesion of dust and the like.

  The lamination method of the hard coat surface protective layer 5 may be a known technique and is not limited at all, but a gravure coating method is generally used. The thickness is preferably about 3 to 20 μm. However, in the case of the gravure coating method, the film thickness that can be coated at one time is about several μm. If the thickness is larger than that, problems such as uneven coating may occur. In that case, a method of coating repeatedly to a desired thickness in a plurality of times is preferably used.

  As the thickness of the hard coat surface protective layer 5 increases, the scratch resistance increases and the result of the pencil hardness test tends to be improved. However, when the hard coat surface protective layer 5 is lapped, the hard coat surface protective layer 5 It also has the problem of easily causing cracks and cracks. From these balances, the appropriate thickness is preferably in the range of 3 to 50 μm.

  The decorative board produced using the mirror surface decorative sheet of the present invention has stain resistance and chemical resistance, can select an extrusion lamination method with high production efficiency such as an extrusion lamination method, and has no concern about hydrolysis. Although it is a decorative sheet, it has both high definition and flexibility and can withstand long-term use.

  As the base sheet 1, a random polypropylene resin having a differential scanning calorimetry melting point of 140 ° C. and ethylene content of 4% in monomer units, 6% by weight of titanium oxide, “Irganox 1076” as a phenolic antioxidant ( 0.2% by weight of BASF Japan Co., Ltd., “Ilfugafos 168” (manufactured by BASF Japan) as a phosphorus processing stabilizer, and “Kimasorb 944” (manufactured by BASF Japan) as a hindered amine light stabilizer. ) Was added in an amount of 0.3% by weight, respectively, and melt extruded using a T-die extruder at an extrusion temperature of 230 ° C. and an extrusion thickness of 70 μm, and both surfaces were subjected to corona treatment.

  On the base material sheet 1, a wood grain pattern was applied as a pattern layer 2 using a pattern ink (“Lamister” manufactured by Toyo Ink Manufacturing Co., Ltd.) by a gravure printing method.

  As an adhesive layer 3 on the pattern layer 2, "Takelac A-520" (main agent; manufactured by Mitsui Chemicals), "Takenate A-80" (curing agent) ; Mitsui Chemicals Co., Ltd.) is blended with the main agent / curing agent = 9/1, adjusted to a solid content of 30% with an ethyl acetate solvent, and then converted to a solid content thickness of about 5 μm by gravure printing. And dried in an oven at 60 ° C. for 2 minutes to volatilize the solvent component.

  On the other hand, as the transparent olefin resin layer 4, 80 wt. Of a random polypropylene resin (“Prime Polypro Y-2045GP” manufactured by Prime Polymer Co., Ltd., MFR = 20) containing 4.3% of ethylene as a monomer unit as the resin (A). %, A sample with 20% by weight of “Notio PN-2070” (Mitsui Chemical Co., Ltd., MFR = 7.0) as the resin (B) was prepared, melt-kneaded and extruded at an extrusion temperature of 230 ° C., and T-die A transparent polypropylene resin sheet was obtained by casting to form a film.

In addition, among the above resins, “Notio PN-2070” has a propylene-derived structural unit content of 71 mol%, and as a structural unit other than the propylene-derived structural unit, it is derived from ethylene and 1-butene. It contains a structural unit. Its physical properties are as follows: Shore A hardness (ASTM-D2240) is 75, melting point is 138 ° C, density (ASTM-D1505) is 867 kg / m ³ , glass transition temperature (Tg) is -29 ° C, and the crystal has a network structure. The crystal lamella has a fine fold structure of 100 nm or less.

  After performing corona treatment on both the front and back surfaces of the transparent olefin resin layer 4, and pasting on the coated surface side of the adhesive layer 3 of the base sheet 1, aging is performed for 3 days in a 60 ° C. environment. A mirror surface decorative sheet was prepared.

  As the resin (A), a random polypropylene resin containing 4.3% of ethylene in monomer units (“Prime Polypro Y-2045GP” manufactured by Prime Polymer Co., Ltd., MFR = 20) is 60% by weight as the resin (B). A mirror surface decorative sheet was produced in the same manner as in Example 1 except that 40% by weight of “Notio PN-2070” (manufactured by Mitsui Chemicals, Inc., MFR = 7.0) was used.

  As the resin (A), 40% by weight of a random polypropylene resin (“Prime Polypro Y-2045GP” manufactured by Prime Polymer Co., Ltd., MFR = 20) containing 4.3% of ethylene as a monomer unit is used as the resin (B). A mirror surface decorative sheet was produced in the same manner as in Example 1 except that "Notio PN-2070" (Mitsui Chemical Co., Ltd., MFR = 7.0) was changed to 60% by weight.

  As the hard coat surface protective layer 5 on the outermost layer, a two-component curable acrylic coating solution “UC Clear W-184” (main agent; manufactured by DIC Graphics Co., Ltd.) and “W-325N” (curing agent; DIC Graphics Co., Ltd.) was blended with the base agent / curing agent = 10/1, the solid content was adjusted to 20% with an ethyl acetate solvent, and then converted to a solid content thickness of about 3 μm by the wire bar coating method. Coated so that. By repeating the same coating three times, the thickness of the hard coat surface protective layer 5 was set to 9 μm, and further aging was performed in a 60 ° C. environment for 2 days to prepare a mirror-finished decorative sheet. The “UC Clear W-184” and the curing agent “W-325N” used for the hard coat surface protective layer 5 do not contain a weather resistance stabilizer.

  When melt-kneading the transparent olefin resin layer 4, 0.5 wt% of benzotriazole UV absorber “Tinuvin P” (manufactured by BASF Corporation) as a weather resistance stabilizer, hindered amine light stabilizer “Kimasorb 2020” A mirror-finished decorative sheet was obtained using the same method as in Example 4 except that 0.5% by weight (BASF) was added. The molecular weight of “Tinubin P” is 225, and the molecular weight of “Chimasorb 2020” is about 2600 to 3400.

  A mirror surface decorative sheet was obtained in the same manner as in Example 5 except that “Tinuvin 234” (BASF Corp.) was added instead of “Tinuvin P” (BASF Corp.). Tinuvin 234 has a molecular weight of 447.6.

  When the hard coat surface protective layer 5 is applied, as a weather resistance stabilizer, benzotriazole-based ultraviolet absorber “Tinuvin PS” (manufactured by BASF Corporation) is used at a solid content ratio of “W-184”. A mirror surface decorative sheet was obtained in the same manner as in Example 3 except that 5% by weight of hindered amine light stabilizer “Tinuvin 123” (BASF Co., Ltd.) was added. The molecular weight of “Tinuvin PS” is 225, and the molecular weight of “Tinuvin 123” is 737.2.

  A mirror surface decorative sheet was obtained using the same method as in Example 7 except that “Tinuvin 900” (manufactured by BASF Corporation) was added instead of “Tinuvin PS”. Tinuvin 900 has a molecular weight of 447.6.

  When the hard coat surface protective layer 5 is applied, a benzotriazole-based ultraviolet absorber “Tinuvin Tinuvin 900” (manufactured by BASF Corporation) is used as a weather resistance stabilizer in a solid content ratio with respect to “W-184”. A mirror surface decorative sheet was obtained in the same manner as in Example 6 except that 8% by weight and 5% by weight of the hindered amine light stabilizer “Tinuvin 123” (BASF Co., Ltd.) were added.

<Comparative Example 1>
A mirror surface decorative sheet was obtained using the same method as in Example 1 except that an acrylic film “Acryprene” (manufactured by Mitsubishi Rayon Co., Ltd.) having a thickness of 50 μm was used instead of the transparent olefin resin layer 4.

<Comparative example 2>
A mirror surface decorative sheet was obtained using the same method as in Example 1 except that a biaxially stretched polyethylene terephthalate film (Mitsubishi Rayon Co., Ltd.) having a thickness of 50 μm was used instead of the transparent olefin resin layer 4. .

<Comparative Example 3>
A mirror-finished decorative sheet was obtained using the same method as in Example 1 except that an unstretched polyethylene terephthalate film (manufactured by Polytech Co., Ltd.) having a thickness of 50 μm was used instead of the transparent olefin resin layer 4.

<Comparative Example 4>
Example 1 except that the propylene elastomer “Prime TPO R110MP” (manufactured by Prime Polymer Co., Ltd., MFR = 2.5) was used instead of “Notio PN-2070” of the resin (B) described in Example 1. Using the same method as in No. 1, a specular decorative sheet was obtained. “Prime TPO R110MP” has a propylene-derived constituent unit content of 60 mol%, and ethylene-containing constituent units other than propylene-derived constituent units are 40 mol%. The physical properties are as follows: Shore A hardness (ASTM-D2240) is 68, melting point is 155 ° C., density (ASTM-D1505) is 880 kg / m ³ , and glass transition temperature (Tg) is −20 ° C.

<Solvent resistance>
Absorbent cotton impregnated with methyl ethyl ketone solvent is placed on the front side of the mirror-finished decorative sheets of Examples 1 to 3 and Comparative Examples 1 to 4, and further covered with a watch glass to prevent volatilization. Left for hours. Thereafter, the decorative sheet surface layer was washed away with running tap water and further naturally dried for 72 hours to confirm the state of the mirror-finished decorative sheet.

<High definition (transparency)>
About the single layer of the transparent olefin resin layer 4 at the time of mirror surface decorative sheet preparation of Examples 1-3 and Comparative Examples 1-4, Sunshine weather meter S-80BBR (Suga Test Instruments Co., Ltd. test conditions: Black panel temperature 63 A continuous light irradiation test was conducted in a continuous irradiation mode (no shower spraying), and the visible light transmittance after 100 hours was measured. The visible light transmittance was measured as a mean value by measuring transmittance values at wavelengths of 400 to 700 nm using a U-3900H spectrophotometer (manufactured by Hitachi High-Technologies Corporation).

<Wrapping aptitude>
A solvent-based adhesive was applied to the back surfaces of the mirror-finished decorative sheets of Examples 1 to 3 and Comparative Examples 1 to 4, and lapping was performed on the wood-based member having a complicated shape. The state of the member immediately after wrapping was confirmed, and the presence or absence of flaking or floating of the sheet from the wooden member was visually observed.

<Performance comparison results>
Table 1 shows the evaluation results of solvent resistance, high definition (transparency), and lapping suitability.

  As can be seen from the results in Table 1, when no olefin copolymer is used as in Comparative Examples 1 to 3, it is difficult to achieve both solvent resistance and lapping suitability. Since Comparative Example 4 uses an olefin-based copolymer, both solvent resistance and lapping suitability are compatible. However, since the high-definition property after the accelerated weathering test is poor, the transparency in the initial stage of production is temporarily low. Even if secured, the condition does not continue for a long time. Therefore, as a mirror surface decorative sheet, it does not become high-definition over time.

<Weather resistance>
On a woody base material having a thickness of about 5 mm, ethylene-vinyl acetate copolymer resin emulsion adhesive “Rikabond BA-10L” (manufactured by Chuo Rika Kogyo Co., Ltd.) 100% by weight as a curing accelerator “BA- 11B "(manufactured by Chuo Rika Kogyo Co., Ltd.) added at a rate of 2.5% by weight and uniformly stirred at a coating amount of 80 g / m <2>. Were aged for 3 days in a room temperature (20-30 ° C.) environment. The prepared sample was cut to a size of 50 mm × 150 mm and subjected to waterproofing treatment by sealing the side surface and the back surface, and then “Sunshine Weather Meter S-80BBR” (manufactured by Suga Test Instruments Co., Ltd. Test condition: Black panel temperature 63 ° C. , 18 minutes of pure water shower spraying in 120 minutes) was performed, and by observing the sample every 250 hours, the time when the deterioration of the design property began to be set was visually confirmed. As an evaluation method, the state where the design property is maintained is “◯”, and the state where the design is deteriorated is “x”.

  Table 2 shows the evaluation results of the weather resistance of each mirror-finished decorative sheet of Examples 1-9.

  From the results in Table 2, it can be seen that all the mirror-finished decorative sheets of the present invention have weather resistance equivalent to 500 hours or more with a sunshine weather meter. Further, as in Example 4, by providing the hard coat surface protective layer 5, the weather resistance is extended to 750 hours. This is presumably because the transparent olefin resin layer 4 is not the outermost surface layer, so that it is less susceptible to internal additive bleed out and shower water in the accelerated test. In addition, by formulating a weathering agent in the transparent olefin resin layer 4 and the hard coat surface protective layer 5, the weathering performance is further improved, and by limiting the additive to one having a molecular weight of 400 or more, the weathering performance is It turns out that it is improving further.

  Since the mirror surface decorative sheet of the present invention does not use any vinyl chloride, there is no concern about environmental problems. Furthermore, since it has stain resistance and chemical resistance, and at the same time has both high definition and flexibility, it can provide a mirror surface decorative sheet that is highly designed and excellent in post-processing such as lapping.

DESCRIPTION OF SYMBOLS 1 ... Base material sheet 2 ... Pattern layer 3 ... Adhesive layer 4 ... Transparent olefin resin layer 5 ... Hard-coat surface protective layer

Claims (5)

In the mirror surface decorative sheet having at least a pattern layer and a transparent olefin resin layer in this order on the base material sheet, the transparent olefin resin layer is:
(1) Propylene as a main raw material, including a copolymer composed of two or more olefins composed of ethylene and / or an α-olefin other than propylene having 3 to 20 carbon atoms,
(2) The copolymer composed of two or more kinds of olefins has a Shore A hardness of 65 to 90 according to the compliance standard ASTM D2240, a density of 860 to 875 kg / m ³ according to the compliance standard ASTM D1505, and a glass transition temperature by differential scanning calorimetry. −35 to −25 ° C., melting point 130 to 170 ° C.
(3) The specular decorative sheet, wherein the copolymer has a crystal having a network structure, and a lamella of the crystal has a folded structure of 100 nm or less.   Randomly obtained by random copolymerizing two or more olefins comprising propylene as a main raw material and ethylene and / or an α-olefin other than propylene having 3 to 20 carbon atoms in 100% by weight of the transparent olefin resin. The mirror surface decorative sheet according to claim 1, comprising 50% by weight or less of polypropylene resin.   The mirror surface decorative sheet according to claim 1, further comprising a hard coat surface protective layer that is three-dimensionally crosslinked on the outermost surface.   The specular decorative sheet according to any one of claims 1 to 3, wherein a weather resistance stabilizer is added to at least one of the transparent olefin resin layer and the hard coat surface protective layer.   The specular decorative sheet according to claim 4, wherein the weather stabilizer has a molecular weight of 400 or more.