JP2014087984A - Decorative sheet and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decorative sheet having working easiness into a cubic shape, and having high productivity.SOLUTION: The decorative sheet 10 comprises: a substrate sheet 11; a pattern layer 12 formed on the substrate sheet; an adhesive layer 13 formed on the pattern layer 12 and including a vinyl chloride-vinyl acetate copolymer; and a surface protective layer 14 formed on the adhesive layer 13 and including a thermoplastic polyurethane elastomer. By this constitution, the outermost surface of the decorative sheet is covered with the thermoplastic polyurethane elastomer, thus the flexibility and durability of the decorative sheet increase.

Description

  The present invention relates to a decorative sheet, and particularly to a decorative sheet provided with a specific surface protective layer.

  Conventionally, there is a decorative sheet used for decorating the surface of an article. The decorative sheet is a base sheet provided with a decorative layer composed of a design layer, an adhesive layer, and the like. As a method of decorating the surface of an article with a decorative sheet, there is a method of three-dimensionally bonding the decorative sheet to the surface of a three-dimensional article by heating and pressing the decorative sheet. When the article is a three-dimensional resin molded product used for a mobile phone or a personal computer housing, the simultaneous molding insert method is used. The simultaneous molding insert method is to insert a decorative sheet in a mold cavity in a state where the decorative sheet is placed, inject a molten resin into the mold, and then cool to obtain a three-dimensional resin molded product. At the same time, a decorative sheet is bonded to the surface of the three-dimensional resin molded product to decorate the surface of the three-dimensional resin molded product.

  In the above decoration, in order to improve the surface strength of the article after decoration, a transparent thermoplastic resin layer composed of a surface protective layer and an intermediate layer is provided on the top surface of the decorative sheet, and a multilayer extruder is used. In some cases, it is provided by extrusion (see Patent Document 1).

Japanese Patent No. 2630159

  In the conventional decorative sheet as described above, a process of applying an adhesive is required for adhesion of the extruded film, and the process and equipment are complicated. In addition, when the uppermost surface is formed of a thermoplastic polyurethane elastomer for easy processing into a three-dimensional shape, it is difficult to select an adhesive having good adhesion to the thermoplastic polyurethane elastomer. For example, sufficient adhesive force cannot be obtained with the adhesives exemplified in the above-mentioned documents.

  The present invention has been made in order to solve the above-described problems, and an object thereof is to provide a decorative sheet having high processability into a three-dimensional shape and high productivity.

  In order to achieve the above object, the first invention is formed on a base sheet, an adhesive layer formed on the base sheet, the vinyl chloride-vinyl acetate copolymer as a main component, and an adhesive layer. And a decorative sheet comprising a surface protective layer mainly composed of a thermoplastic polyurethane elastomer.

  If comprised in this way, since the uppermost surface of a decorating sheet is covered with a thermoplastic polyurethane elastomer, the softness | flexibility and durability of a decorating sheet will go up.

  2nd invention is a decoration sheet | seat provided with the pattern layer formed between the base sheet and the contact bonding layer in the structure of 1st invention.

  If comprised in this way, since a design layer is formed in a desired position, the decorating sheet excellent in the designability can be obtained.

  3rd invention is a decoration sheet | seat whose rubber hardness of a thermoplastic polyurethane elastomer is the Shore A hardness of 90 or more in the structure of 1st or 2nd invention.

  If comprised in this way, since the uppermost surface of a decorating sheet is covered with the thermoplastic polyurethane elastomer of predetermined | prescribed rubber hardness, the self-restorability of a decorating sheet can fully be acquired.

  A fourth invention is a decorative sheet according to any one of the first to third inventions, wherein the glass transition temperature of the vinyl chloride-vinyl acetate copolymer is 80 ° C. or lower.

  If comprised in this way, since an adhesive layer will melt when shape | molding a surface protective layer, an adhesive layer will adhere | attach firmly with a surface protective layer

  According to a fifth invention, in any one of the first to fourth inventions, the base sheet includes a first high hardness layer, a heat-resistant layer formed thereon, and a second high layer formed thereon. A decorative sheet including a hardness layer.

  If comprised in this way, since a heat resistant layer is provided in the middle of a base sheet, the heat resistance of a decorating sheet improves.

  A sixth invention is a decorative sheet in which the surface protective layer is formed by melt extrusion molding in any one of the first to fifth inventions.

  The seventh invention includes a step of forming a design layer on the base sheet, a step of forming an adhesive layer on the design layer, and a surface protective layer mainly composed of a thermoplastic polyurethane elastomer on the adhesive layer. And a process for producing a decorative sheet comprising a step of forming by melt extrusion molding.

  If comprised in this way, since a surface protective layer is directly formed in the base sheet in which the pattern layer and the contact bonding layer were formed, post-processes, such as dry lamination, become unnecessary, and a decorating sheet can be manufactured easily.

  According to this invention, it is easy to process into a three-dimensional shape, and a decorative sheet with high productivity can be obtained. Moreover, such a decorative sheet can be obtained by an easy manufacturing method.

It is sectional drawing which showed the structure of the decorating sheet by 1st Embodiment of this invention. It is sectional drawing which showed the structure of the decorating sheet by 2nd Embodiment of this invention. It is explanatory drawing which showed schematic structure of the melt extrusion molding machine by 3rd Embodiment of this invention.

  With reference to FIG. 1, the decoration sheet 10 by 1st Embodiment of this invention is demonstrated. The decorative sheet 10 includes a base sheet 11, a design layer 12 formed on the base sheet, an adhesive layer 13 formed on the design layer 12 and mainly composed of a vinyl chloride-vinyl acetate copolymer, And a surface protective layer 14 mainly composed of a thermoplastic polyurethane elastomer formed on the adhesive layer 13. The decorative sheet 10 is bonded to the surface of a three-dimensional article by a method such as roll transfer, press transfer, or a simultaneous molding insert method. In the simultaneous molding insert method, (1) the decorative sheet is placed in the mold cavity and sandwiched in the mold, the decorative sheet is heated with a heat source, preformed, and then melted in the mold A method of obtaining a three-dimensional resin molded product by injecting a resin and then cooling it, (2) A flat decorative sheet is placed in the mold cavity and sandwiched in the mold, and the molten resin is put in the mold It is conceivable to obtain a three-dimensional resin molded product by cooling after injection. In addition, the decorative sheet 10 may include other layers such as an anchor layer for improving adhesion between the layers of each layer, or may include a plurality of design layers.

  As the base sheet 11, a sheet material conventionally used for the purpose of supporting the design layer 12 and the like on the sheet can be used. As a constituent material of the base sheet 11, polypropylene, polyethylene, polyamide, polyimide, polystyrene, polyester, acrylic, polyvinyl chloride, polycarbonate, PBT resin, ABS resin film, and the like can be used.

  The thickness of the base sheet 11 is preferably 50 μm to 400 μm, and more preferably 100 μm to 188 μm. If the thickness of the base sheet 11 is 50 μm or less, the base sheet 11 is likely to be wrinkled when it is bonded to the surface of the article, making it difficult to handle. Moreover, if it is 400 micrometers or more, the thickness of the article | item after bonding the decorating sheet 10 will become thick.

  The design layer 12 is a layer for expressing a design. The design layer 12 is formed using a colored ink containing at least a colorant and a synthetic resin that serves as a binder. As the synthetic resin serving as the binder of the pattern layer 12, polyvinyl resin, polyamide resin, polyester, polyacrylic resin, polyurethane resin, polyvinyl acetal resin, polyester urethane resin, cellulose ester resin, alkyd resin, and the like can be used. Examples of the colorant contained in the colored ink of the design layer 12 include pigments and dyes. Examples of pigments include (1) plant pigments such as indigo, alizarin, carsamine, anthocyanin, flavonoid, shikonin, (2) food pigments such as azo, xanthene, triphenylmethane, and (3) natural inorganic pigments such as loess and green soil. (4) Calcium carbonate, titanium oxide, aluminum lake, muder lake, cochineal lake and the like.

  The thickness of the pattern layer 12 is preferably 0.5 μm to 10 μm, and more preferably 1 μm to 5 μm. If the thickness of the pattern layer 12 is 0.5 μm or less, it will be transparent and the design cannot be expressed. If it is 10 μm or more, there will be a large step between where the pattern layer 12 is formed and where it is not formed. Therefore, it becomes difficult to form the adhesive layer 13 or the design layer 12 is broken.

  The adhesive layer 13 is a layer for improving the adhesiveness between the surface protective layer 14 and other layers. The adhesive layer 13 is a layer mainly composed of vinyl chloride-vinyl acetate copolymer, and the vinyl chloride-vinyl acetate copolymer preferably has a glass transition temperature of 80 ° C. or lower. When the glass transition temperature is 80 ° C. or higher, the adhesive layer 13 is not melted when the surface protective layer 14 is molded, and sufficient adhesion cannot be obtained.

  The thickness of the adhesive layer 13 is preferably 1 μm to 30 μm, and more preferably 2 μm to 5 μm. If the thickness of the adhesive layer 13 is between 1 and 30 μm, sufficient adhesion can be obtained.

The surface protective layer 14 is a layer that becomes the uppermost surface when the decorative sheet 10 is bonded to the surface of a three-dimensional article. The surface protective layer 14 is mainly composed of a thermoplastic polyurethane elastomer. The thermoplastic polyurethane elastomer preferably has a rubber hardness of Shore A hardness of 90 or more. This is because when the rubber hardness is 90 or more Shore A hardness, sufficient self-repairing property can be obtained. Here, the rubber hardness is a value measured in accordance with Japanese Industrial Standard (JIS) K6253A. The measurement conditions were a sample piece of 6 mm thickness, temperature 23 ± 2 ° C., humidity 50 ± 5%, and measurement time 15 seconds.

  The thickness of the surface protective layer 14 is preferably 25 μm to 300 μm, and more preferably 50 μm to 100 μm. If the surface protective layer 14 is 300 μm or more, three-dimensional processing becomes difficult when the decorative sheet 10 is bonded to the surface of the article in a subsequent step, and if it is 25 μm or less, sufficient self-repairing can be obtained. Can not.

  As described above, since the uppermost surface of the decorative sheet 10 is covered with the thermoplastic polyurethane elastomer, the flexibility and durability of the decorative sheet 10 are improved. When the flexibility and durability of the decorative sheet 10 are improved, the sheet will not crack even if a three-dimensional shape process such as pre-forming is performed when the decorative sheet 10 is bonded to the surface of the article. Since the pattern can be formed at a desired position by providing the pattern layer 12, the decorative sheet 10 is excellent in design. Since the vinyl chloride-vinyl acetate copolymer, which is the main component of the adhesive layer 13, has a glass transition temperature of 80 ° C. or lower, the adhesive layer melts when the surface protective layer is formed, and the adhesive layer becomes the surface protective layer. Adhere firmly. Since the thermoplastic polyurethane elastomer which is the main component of the surface protective layer 14 has a Shore A hardness of 90 or more, the uppermost surface of the decorative sheet 10 is covered with a thermoplastic polyurethane elastomer having a predetermined rubber hardness, so that the self-healing property is improved. You can get enough.

  A decorative sheet 10A according to a second embodiment of the present invention will be described. Referring to FIG. 2, the decorative sheet 10A has the same configuration as that of the first embodiment except for the layer structure of the base sheet 11A, and therefore only the differences will be described here.

  The base sheet 11A includes a first high-hardness layer 15, a heat-resistant layer 16 formed thereon, and a second high-hardness layer 17 formed thereon. In other words, the heat-resistant layer 16 has a structure sandwiched between the first high hardness layer 15 and the second high hardness layer 17.

  As the material of the first high hardness layer 15, an acrylic synthetic resin or the like can be used. Further, the hardness of the first high hardness layer is preferably pencil hardness FH.

  As a material for the heat-resistant layer 16, polystyrene, polycarbonate, or the like can be used. The glass transition temperature of the heat-resistant layer 16 is preferably 140 ° C to 150 ° C. If the glass transition temperature is 140 ° C. or lower, sufficient heat resistance of the base sheet 11A cannot be obtained, and if it is 150 ° C. or higher, workability is deteriorated.

  The material of the second high hardness layer 17 is preferably the same as that of the first high hardness layer 15. This is because if the materials of the first high hardness layer 15 and the second high hardness layer 17 are the same, there is no possibility that the sheet will be warped or distorted when the base sheet 11A is heat-treated.

  The thickness of the base sheet 11A is preferably 50 μm to 400 μm, and more preferably 100 μm to 188 μm. The thickness of the heat-resistant layer 16 is preferably 60% to 90% of the total thickness of the base sheet 11A. If the thickness of the heat-resistant layer 16 is within this range, sufficient heat resistance can be obtained, and shrinkage of the sheet can be suppressed when the base sheet 11A is heat-treated.

  The first high hardness layer 15 and the second high hardness layer 17 are preferably the same in thickness. This is because if the thicknesses of the first high hardness layer 15 and the second high hardness layer 17 are the same, there is no possibility that the sheet is warped or distorted when the base sheet 11A is heat-treated.

  The manufacturing method of the base sheet 11A can be selected from thermal lamination and coextrusion multilayer molding. A coextrusion multilayer molding method is particularly preferred because the number of steps can be reduced.

  The decorative sheet 10 </ b> A includes a base sheet 11 </ b> A, a design layer 12, an adhesive layer 13, and a surface protective layer 14. The base sheet 11 </ b> A includes a first high hardness layer 15, a heat resistant layer 16, and a second high hardness layer 17. By providing the heat resistant layer 16 in the middle, the heat resistance of the base sheet 11A is improved, and the heat resistance of the decorative sheet 10A is also improved.

  The manufacturing method of the decorating sheet 10 by 3rd Embodiment of this invention is demonstrated. The method of manufacturing the decorative sheet 10 includes a step of forming the design layer 12 on the base sheet 11, a step of forming the adhesive layer 13 on the design layer 12, and a thermoplastic polyurethane resin elastomer on the adhesive layer 13. And a step of forming the surface protective layer 14 made of by melt extrusion molding.

  First, the design layer 12 is formed on the base sheet 11. As a method for forming the pattern layer 12, a known thin film manufacturing technique can be employed. For example, a printing method such as a gravure printing method, a screen printing method, an offset printing method, or a flexographic printing method can be employed. In particular, the gravure printing method and the offset printing method are suitable for performing multicolor printing and gradation expression. In the case of a single color, a coating method such as a gravure coating method, a roll coating method, or a comma coating method may be employed.

  Next, the adhesive layer 13 is formed on the design layer 12. As a method for forming the adhesive layer 13, a known thin film manufacturing technique can be employed. For example, a printing method such as a gravure printing method, a screen printing method, an offset printing method, or a flexographic printing method can be employed. In particular, the gravure printing method and the offset printing method are suitable for performing multicolor printing and gradation expression. In the case of a single color, a coating method such as a gravure coating method, a roll coating method, or a comma coating method may be employed.

  Next, the surface protective layer 14 is formed on the adhesive layer 13. As a method of forming the surface protective layer 14, melt extrusion molding is preferable.

  With reference to FIG. 3, the base sheet 11 on which the design layer 12 and the adhesive layer 13 are formed is set on the unwinding portion 21 of the melt extrusion molding machine and unwound on the pressure roll 22. The thermoplastic polyurethane elastomer melted in the extruder 23 is extruded in the form of a sheet from the discharge port 25 of the T-die 24 in the vertical direction, and is laminated on the adhesive layer 13 as the surface protective layer 14. Thereafter, the melted surface protective layer 14 is cooled by the cooling roll 26, and the completed decorative sheet 10 is taken up by the take-up unit 27.

  As a base material sheet, an easily molded two-type three-layer coextruded product of acryl layer and polycarbonate layer (No-clean manufactured by RP Topra Co., Ltd.) was used. For the adhesive layer, a copolymer of vinyl chloride and vinyl acetate was used. On this, an ester thermoplastic polyurethane elastomer having a Shore A hardness of 96 was extruded using a T-die, and a surface protective layer was produced and laminated at the same time. The thickness of each layer was a pattern layer of 3 μm, an adhesive layer of 3 μm, and a surface protective layer of 30 μm.

DESCRIPTION OF SYMBOLS 10, 10A Decorating sheet 11, 11A Base sheet 12 Pattern layer 13 Adhesive layer 14 Surface protective layer 15 1st high hardness layer 16 Heat resistant layer 17 2nd high hardness layer 20 Melt extrusion machine 21 Unwinding part 22 Pressure roll 23 Extruder 24 T die 25 Discharge port 26 Cooling roll 27 Winding part

Claims (7)

A base sheet;
An adhesive layer formed on the base sheet and mainly composed of a vinyl chloride-vinyl acetate copolymer;
A decorative sheet comprising a surface protective layer formed on the adhesive layer and mainly composed of a thermoplastic polyurethane elastomer.   The decorative sheet according to claim 1, comprising a pattern layer formed between the base sheet and the adhesive layer.   The decorative sheet according to claim 1 or 2, wherein the thermoplastic polyurethane elastomer has a rubber hardness of Shore A hardness of 90 or more.   The decorative sheet according to any one of claims 1 to 3, wherein the vinyl chloride-vinyl acetate copolymer has a glass transition temperature of 80 ° C or lower.   5. The base sheet according to claim 1, wherein the base sheet includes a first high-hardness layer, a heat-resistant layer formed thereon, and a second high-hardness layer formed thereon. Decorative sheet.   The decorative sheet according to any one of claims 1 to 5, wherein the surface protective layer is formed by melt extrusion molding. Forming a pattern layer on the base sheet;
Forming an adhesive layer on the design layer;
A process for producing a decorative sheet, comprising: forming a surface protective layer mainly composed of a thermoplastic polyurethane elastomer on the adhesive layer by melt extrusion molding.

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