JP2010069729A - Heat molding decorative sheet and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To materialize a decorative sheet in which no embossment flow occurs during heating molding. <P>SOLUTION: The decorative sheet comprises a thermoplastic resin substrate layer 1A in which an uneven pattern a is formed. An electron beam crosslinked layer e is formed in a surface layer in which the uneven pattern a is formed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a decorative sheet for thermoforming and a method for producing the same.

  As a decorative sheet, a sheet having a three-dimensional pattern on its surface is particularly known in order to enhance its design. In order to obtain a three-dimensional pattern, the surface is embossed with an uneven pattern. In this way, the decorative sheet having a concavo-convex pattern on the surface can provide a simple three-dimensional effect, but cannot derive an effective design property that produces a sense of depth, for example. In addition, if there are uneven patterns on the surface, dust and dirt are likely to accumulate in the recesses, and it is also difficult to remove the accumulated dust and dirt, so there is a problem that the design properties deteriorate with the passage of time after pasting . Furthermore, since the uneven pattern on the surface may collapse due to wear or scratches, there is a problem that it is difficult to apply to the surface of a movable object or a place where it is easy to touch.

In order to solve such problems, a so-called decorative sheet called internal embossing is known in which an uneven pattern is formed inside. Patent Document 1 below describes a laminate in which a thermoplastic synthetic resin sheet provided with an embossed concavo-convex pattern and a transparent synthetic resin sheet are bonded together by a dry laminating method using a two-component urethane-based transparent adhesive or the like. The following Patent Document 2 discloses a PVC in which a concave / convex pattern made of an ultraviolet curable resin is formed on the back surface of a transparent resin sheet such as a polyvinyl chloride (PVC) sheet, and vent holes are formed in the concave / convex pattern surface of the sheet. The sheet is heat laminated.
Japanese Patent Publication No. 7-22989 JP 10-34780 A

  The decorative sheet on which the concavo-convex pattern as described above is formed may be subjected to heat forming according to the surface shape of the object to be laid after the sheet is formed. For example, in the case of a decorative sheet for a vehicle interior, the decorative sheet is thermoformed according to the curvature of the surface shape of the dashboard, door trim, console box, and other parts.

  In this way, when a decorative sheet on which a concavo-convex pattern is formed is thermoformed, the concavo-convex pattern flows due to the thermoplasticity of the base material layer provided with the concavo-convex pattern, and the concavo-convex pattern that has been applied cannot be effectively visually recognized. There is. In particular, as described above, in a decorative sheet called an internal embossing having an uneven pattern formed therein, the design properties are significantly reduced by the embossing flow at the time of heat forming even though the internal embossing is applied by a multilayer structure. There's a problem.

  Furthermore, in the thing of patent document 1, since the solvent is contained in the adhesive agent used for dry lamination, since the solvent component which remained in the sheet | seat vaporizes and foams at the time of thermoforming, a bubble arises inside a sheet | seat and external appearance This is not suitable for use in places with high airtightness, for example, for vehicle interiors, because there is a problem that the solvent component tends to be adversely affected and the solvent component becomes volatile organic waste (VOC). In order to skip the solvent component, a drying process is required separately, which causes a problem that the manufacturing process becomes complicated and leads to an increase in cost.

  On the other hand, in the case of the one described in Patent Document 2, since the layer filling the unevenness is a PVC sheet that is thermally laminated, when the sheet thickness is thinly formed, the surface follows the emboss during lamination and becomes a crusty skin shape. Cheap. Therefore, when the unevenness is directed to the surface side, the flatness of the surface cannot be obtained, and an effective design with a sense of depth in which the uneven pattern exists inside the flat surface cannot be obtained. This problem becomes more noticeable when the emboss depth is deep. Further, there is a problem that the heat laminating layer is melted at the time of thermoforming, and the surface easily follows the uneven pattern inside. Furthermore, since the ultraviolet curable resin layer having a concavo-convex pattern is cured once, the elongation at the time of heating is considerably lower than that of other resin layers.

  An object of the present invention is to deal with such a problem. In other words, when heat-molding a decorative sheet on which a concavo-convex pattern is formed, the phenomenon that the concavo-convex pattern flows and the design properties deteriorate (hereinafter, this phenomenon is referred to as “embossing flow”) is avoided, and good thermoformability It is possible to maintain a high rugged design with an embossed pattern, and in particular, to maintain an effective design with a sense of depth while having good heat moldability even in a decorative sheet having a depth-like internal embossing. In addition, the occurrence of VOC does not occur, the complexity of the manufacturing process does not occur, the surface does not become crusty, it can also be applied to patterns with deep embossing, and bubbles and cracks are generated during heat molding, resulting in design It is an object of the present invention that the problem of lowering does not occur.

  In order to achieve such an object, the present invention provides a decorative sheet comprising a base material layer made of a thermoplastic resin having a concavo-convex pattern, and an electron beam cross-linking layer on a surface layer having the concavo-convex pattern formed thereon. Is formed.

  In addition to the above-described features, an intermediate layer that is a transparent or translucent hot melt adhesive layer formed so as to fill the uneven pattern of the base material layer, and a transparent or transparent layer formed on the intermediate layer And an upper layer which is a translucent thermoplastic resin layer.

  As a method for producing such a thermoformable decorative sheet, there are a step of embossing a concavo-convex pattern on the surface of a base material layer made of a thermoplastic resin, and a surface layer by irradiating the surface with the concavo-convex pattern with an electron beam. And a step of forming an electron beam cross-linking layer.

  In addition to the above-described features, a transparent or translucent thermoplastic resin layer is formed on the base material layer via an intermediate layer made of a transparent or translucent hot melt adhesive layer that fills the uneven pattern of the base material layer. It is characterized by heat laminating as a top layer.

  The present invention having such a feature can improve the heat resistance of the uneven surface by irradiating the surface with the uneven pattern with an electron beam to form an electron beam cross-linked layer on the surface layer. It is possible to suppress the embossing flow that occurs when the decorative sheet on which the is formed is thermoformed. As a result, it is possible to obtain a decorative sheet having good heat moldability and no embossing flow. In particular, a decorative sheet having internal embossing can maintain a high design with a sense of depth even by heat molding.

  In addition, by providing a transparent intermediate layer, it is possible to effectively secure the distance from the upper layer to the concave-convex pattern of the base material layer, so that it is possible to obtain an internal embossed decorative sheet having a high design with a sense of depth. By using a hot-melt adhesive that does not contain a solvent component, a decorative sheet that does not generate VOC after formation can be obtained. Since a drying process for removing the solvent component is not required when obtaining a clean decorative sheet free from VOC generation, the manufacturing process is not complicated, and the manufacturing cost can be reduced.

  In the case of forming the intermediate layer, since the upper layer is formed after the uneven pattern is completely flattened by the intermediate layer, the surface does not become crusty even during the formation of the decorative sheet or the subsequent heat molding. In addition, since the thickness of the intermediate layer can be determined according to the depth of the emboss, it can be applied to a deep embossed pattern. By using a hot-melt adhesive, the base material layer, intermediate layer, and upper layer are formed of thermoplastic resin, so heat moldability is good, and bubbles are generated during heat-molding because it is a solvent-free hot-melt adhesive. There is no problem, and there is no problem that cracks occur during heat forming due to the reheat processability of the hot melt adhesive.

Embodiments of the present invention will be described below. FIG. 1 is an explanatory view illustrating a decorative sheet and a method for manufacturing the decorative sheet according to an embodiment of the present invention. The decorative sheet according to the embodiment of the present invention includes a base material layer 1A made of a thermoplastic resin on which an uneven pattern a is formed, and an electron beam cross-linking layer e is formed on the surface layer on which the uneven pattern a is formed. In order to form the concavo-convex pattern a on the base material layer 1A, as shown in FIG. 3A, embossing is performed to press the embossing roller 2 (or embossing plate) on the surface of the base material layer 1A formed into a sheet. In order to form the electron beam cross-linking layer e, as shown in FIG. 2B, the surface on which the concavo-convex pattern a is applied is irradiated with an electron beam e ₀ from the electron beam irradiation device 3, and the electron beam is applied to the surface layer. A crosslinked layer e is formed. Irradiation of the electron beam e ₀ may be carried out while scanning the electron beam irradiation device 3 or substrate layer 1A in a specific direction as shown, it may be uniformly irradiated to the irradiated surface entirely.

  Electron beam irradiation with respect to such a concavo-convex pattern a results in the formation of an electron beam cross-linked layer e on the surface layer on which the concavo-convex pattern a is formed. No embossing flow. The electron beam irradiation conditions are appropriately adjusted according to the material of the base material layer 1A, but the acceleration voltage is adjusted in the range of 10 kV to 300 kV, and the irradiation dose is adjusted in the range of about 10 kGy to 500 kGy.

  The base layer 1A is selected from ABS resin, acrylic resin, urethane resin, polyvinyl chloride (PVC), polyethylene (PE), ethylene vinyl acetate copolymer (EVA), and ethylene-methyl methacrylate (EMMA). Those having one or more kinds of synthetic resins as a main component can be used. When the surface of the base material layer 1A is irradiated with an electron beam, the embossing flow can be suppressed and at the same time the moldability can be improved.

  Although the base material layer 1A is sufficiently effective in preventing embossing flow even when the material is used alone, a crosslinking aid may be added during the blending of the sheet. Effective crosslinking aids include triallyl isocyanurate (TAIC), trimethylolpropane trimethacrylate (TMPT), trimethylolpropane triacrylate (TMPTA), pentaerythritol tetraacrylate (PETTA), dipentaerythritol hexaacrylate (DPHA). And the like.

  FIG. 2 is a schematic cross-sectional view of a decorative sheet according to an embodiment of the present invention. Here, an example of a decorative sheet having internal embossing will be described. The decorative sheet 1 according to the embodiment of the present invention shown in FIG. 1A has the base layer 1A, the intermediate layer 1B, and the upper layer 1C described above. The base material layer 1A is a thermoplastic resin sheet layer on which the above-described uneven pattern a is formed, and an electron beam cross-linking layer is formed on the surface layer on which the uneven pattern a is formed. The intermediate layer 1B is a transparent or translucent hot melt adhesive layer formed on the base layer 1A so as to fill the uneven pattern a formed on the base layer 1A. The upper layer 1C is a transparent or translucent thermoplastic resin layer formed on the intermediate layer 1B.

  Moreover, the decorative sheet 1 according to the embodiment of the present invention shown in FIG. 5B includes a decorative layer 1D in addition to the base layer 1A, the intermediate layer 1B, and the upper layer 1C described above. This decorative layer 1D is formed of a printing layer having various color patterns and / or an aluminum vapor deposition layer, and is provided to improve the design of the uneven pattern a applied on the base material layer 1A.

  For forming the base material layer 1A itself, a well-known sheet forming method such as a T-die extrusion method or a calendar method can be employed, and a sheet material having a thickness of 0.3 to 0.4 mm is preferably formed. Formation of the concavo-convex pattern a on the base material layer 1A can be performed by a known embossing method including a printing and transfer method. More specifically, as shown in FIG. 1, it can apply by pressing the roller-shaped embossing plate which has an uneven | corrugated shape on the surface with respect to the base material layer sheet immediately after thermoforming.

  The decorative layer 1D described above forms a printed layer and / or an aluminum deposited layer by forming a concavo-convex pattern a on the substrate layer 1A and performing an electron beam irradiation treatment, followed by a printing process such as gravure printing or an aluminum deposition process. To do.

  As the hot melt adhesive layer of the intermediate layer 1B, a solventless polyurethane-based, ethylene vinyl acetate (EVA) -based, polyamide-based, polyester-based hot-melt adhesive can be used. The intermediate layer 1B is formed in a layer having a thickness suitable for filling the uneven pattern formed on the base material layer 1A. Preferably, it can be formed to a thickness of about 50 to 100 μm for a base material layer having a thickness of 0.3 to 0.4 mm.

  As a method for forming the intermediate layer 1B, it can be formed by applying to one or both of the base material layer 1A and the upper layer 1C. As the coating method, a gravure printing method, a roller coating method, an offset method, a die coating method, or the like can be used.

  The transparent or translucent resin layer of the upper layer 1C is a thermoplastic resin that can be heat-molded, and can be a resin layer such as an acrylic, olefin, or styrene resin, preferably an acrylic resin layer Can be.

  According to the decorative sheet 1 having such a configuration, a decorative sheet with good heat moldability can be obtained by the laminated structure of the thermoplastic resin layers. Moreover, since the transparent or semi-transparent intermediate layer 1B is interposed, the distance from the upper layer 1C to the uneven pattern a of the base material layer 1A can be effectively ensured, and the unevenness formed on the base material layer 1A. A sufficient depth feeling can be given to the pattern a, and an effective design can be given to the uneven pattern a having a depth feeling due to the refractive index relationship between the upper layer 1C and the intermediate layer 1B.

  Further, since the concave / convex pattern a is formed inside the decorative sheet 1, dust or dirt does not collect in the concave portions of the concave / convex pattern a as in the case where the concave / convex pattern is on the surface, and the upper flat surface is formed. Cleaning can easily remove dirt on the surface. Thereby, high designability can be maintained over time after pasting. Furthermore, since the upper layer 1A on the surface serves as a protective layer, the concave / convex pattern a does not collapse due to wear or scratches, and the selectivity of the application portion of the decorative sheet can be enhanced.

  By using a hot melt adhesive that does not contain a solvent component as the intermediate layer 1B, it is possible to obtain a decorative sheet 1 that does not generate VOCs after formation. Since the drying process for removing a solvent component etc. is not required when obtaining the clean decorative sheet 1 which does not generate | occur | produce VOC, the complexity of a manufacturing process does not arise and it becomes possible to reduce manufacturing cost.

  Since the upper layer 1C is formed after the concavo-convex pattern is completely flattened by the intermediate layer 1B, the surface does not become crusty even during the formation of the decorative sheet 1 or the subsequent heat molding. Further, since the thickness of the intermediate layer 1B can be determined according to the depth of the emboss, it can be applied to a pattern with a deep emboss. Since the intermediate layer 1B is a solvent-free hot-melt adhesive, there is no problem that bubbles are generated during heat forming, and there is no problem that cracks are generated during heat forming due to the reheat processability of the hot-melt adhesive.

  And since the electron beam bridge | crosslinking layer is formed in the surface layer in which the uneven | corrugated pattern a was formed in 1 A of base materials layers, an embossing flow does not arise also at the time of heat forming. Therefore, even when curved molding or the like is performed, a high design with a sense of depth can be maintained as it is. Until now, decorative sheets having internal embossing have been laid exclusively on flat laying surfaces such as building materials, and have not been used for laying objects having complicated curved surfaces. This is because the problem of embossing flow cannot be solved and the embossing inside flows at the time of heat forming and cannot be visually recognized. The decorative sheet 1 according to the embodiment of the present invention has solved this problem brilliantly. In particular, in a decorative sheet for vehicle interior that has a complicated curved surface shape as an object to be laid, highly embossed internal embossing is provided. It can be applied effectively.

  Drawing 3 is an explanatory view explaining the manufacturing method of decorative sheet 1 concerning the embodiment of the present invention. FIG. 4A shows a case where a heat laminating method is employed, and FIG. 4B shows a case where a die coater laminating method is adopted.

In the method shown in FIG. 6 (a), it is separately molded base layer sheet 1A ₀ and interlayer sheet 1B ₀ and the upper sheet 1C _0. The substrate layer sheet 1A ₀ is provided with a concavo-convex pattern on the surface thereof by embossing, and the electron beam cross-linking layer e described above is formed. The intermediate layer sheet 1B ₀ is a hot melt adhesive formed into a sheet shape. Then, the base layer sheet 1A ₀ , the intermediate layer sheet 1B ₀ , and the upper layer sheet 1C ₀ are supplied to the outer periphery of the heating roller 13 through the guide rollers 10, 11, and 12, respectively. In this case, interlayer sheet 1B ₀ is stacked on the uneven pattern of the base layer sheet 1A _0, the upper layer sheet 1C ₀ is laminated thereon. The surface of the heating roller is heated to a temperature of 100 to 120 ° C. necessary for thermal lamination. The heat-molded decorative sheet 1 is drawn out through the drawing roller 14.

In the method shown in FIG. (B), it supplies the interlayer sheet 1B ₀ extruded from the die coater 22 (extruder) onto the substrate layer sheet 1A ₀ was pre uneven Pattern subjected substrate layer sheet 1A ₀ supplying an upper sheet 1C ₀ via the guide roller 21 on which a laminate of interlayer sheet 1B ₀ above, hot forming the three layers in the heating roller 20 at the same time.

  According to such a manufacturing method, the decorative sheet 1 according to the embodiment of the present invention can be formed by using a conventional multilayer sheet forming process by thermal lamination.

It is explanatory drawing explaining the decorative sheet which concerns on embodiment of this invention, and its manufacturing method. It is a schematic sectional drawing of the decorative sheet which concerns on embodiment of this invention. It is explanatory drawing explaining the manufacturing method of the decorative sheet which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Decorative sheet 1A Base material layer 1B Intermediate layer 1C Upper layer 1D Decorative layer 10, 11, 12, 21 Guide roller 13, 20 Heating roller 14 Drawer roller 2 Embossing roller 3 Electron beam irradiation device a Concave and convex pattern e Electron beam cross-linking layer 22 Die coater

Claims (5)

A decorative sheet provided with a base material layer made of a thermoplastic resin having an uneven pattern,
A decorative sheet for thermoforming, wherein an electron beam cross-linked layer is formed on a surface layer on which the uneven pattern is formed. An intermediate layer which is a transparent or translucent hot melt adhesive layer formed so as to fill the uneven pattern of the base material layer;
The decorative sheet for thermoforming according to claim 1, further comprising: an upper layer that is a transparent or translucent thermoplastic resin layer formed on the intermediate layer.   The base layer is selected from ABS resin, acrylic resin, urethane resin, polyvinyl chloride (PVC), polyethylene (PE), ethylene vinyl acetate copolymer (EVA), and ethylene-methyl methacrylate (EMMA). The decorative sheet for thermoforming according to claim 1 or 2, wherein one or more kinds of synthetic resins are used as a main component.   Embossing a concavo-convex pattern on the surface of a base material layer made of a thermoplastic resin, and irradiating an electron beam on the surface provided with the concavo-convex pattern to form an electron beam cross-linked layer on the surface layer. A method for producing a decorative sheet for thermoforming.   The substrate layer is thermally laminated with a transparent or translucent thermoplastic resin layer as an upper layer through an intermediate layer composed of a transparent or translucent hot melt adhesive layer that fills the uneven pattern of the substrate layer. The method for producing a decorative sheet for heat molding according to claim 4.

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