JP2008100415A - Method for producing decorative resin molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simultaneously implement the molding of a resin molding and surface decoration and to materialize injection without a turbulent flow during the injection of a molding resin. <P>SOLUTION: In the production of a decorative resin molding, a decorative sheet is placed in a lower mold with its surface side turned down, an upper mold is brought down on the lower mold, and the molding resin is injected between the upper mold and the decorative sheet to mold the resin molding which is laid on the decorative sheet to overlap each other and integrated with the decorative sheet. In molding injection, the injection is carried out by an injection gate having an opening inner diameter width of at least 1/2 of the injection side inner diameters of the upper and lower molds. In this way, remarkable process shortening, productivity improvement, and cost reduction can be materialized, and the decorative resin molding good in surface properties can be obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for decorating the surface of various plastic molded products such as building materials, automobile interior parts, parts of electrical appliances, mobile phone parts, and the like, and aims to improve work efficiency and reduce costs.

Conventionally, as a technique for decorating the surface of resin parts such as key tops and various cases of mobile phones, for example, a decorative film (multilayer laminated film) is adhered to the top and side surfaces of the resin molded body with an adhesive, In addition, characters and the like are printed and displayed, and a transparent resin cover is further covered with an adhesive (described in JP-A 2006-216493, [0041] to [0044], And see FIG. In addition, as shown in FIG. 4, the resin molded body 5 is made by pouring resin from a narrow gate 3 between a pair of lower mold 1 and upper mold 2 for injection molding. It is common to mold.
JP 2006-216493 A

  However, in the invention described in Patent Document 1 described above, the number of steps is large and the productivity is inferior. In the case where the resin molded body 5 which is a resin part is molded by injection molding resin in the upper and lower molds, However, since the opening of the resin injection gate 3 is narrow, the resin turbulently flows. As a result, a unique small fine wrinkle 6 is generated near the injection side of the surface of the finished decorative resin molded body 5a due to a fine shrinkage at the time of injection molding. I can't avoid it.

  Therefore, in the present invention, the number of processes for decorating a resin molded product is reduced, the productivity is improved, and a decorative resin molded product having a good surface property that is free from ugly fines that easily occur during injection molding is reduced. Specifically, according to the first aspect of the present invention, a decorative sheet is laid in the lower mold with the surface side down, and the upper mold is further placed on the lower mold. , A molded resin is injected between the upper mold and the decorative sheet to form a resin molded product, and the decorative resin molded product manufacturing method is integrally molded with the decorative sheet About.

  In the second aspect of the invention, the decorative sheet is laid in the lower mold with the surface side down, and the upper mold is lowered onto the lower mold, and is molded between the upper mold and the decorative sheet. In the case of molding a resin molding by injecting a resin, and molding the decorative sheet with the polymerization sheet, the injection of the molding resin between the upper mold and the decorative sheet is performed on the injection side of the upper and lower molds. The present invention relates to a method for manufacturing a decorative resin molded product that is performed by an injection gate having an opening inner diameter width of at least one half of the inner diameter.

  Furthermore, the third invention lays a decorative sheet in the lower mold with the surface side down, and further lowers the upper mold on the lower mold and forms it between the upper mold and the decorative sheet. In the case of molding a resin molding by injecting a resin, and molding the decorative sheet with the polymerization sheet, the injection of the molding resin between the upper mold and the decorative sheet is performed on the injection side of the upper and lower molds. The inner diameter width is gradually increased from the opening to a position at least a half to one-third of the injection-side inner diameter of the upper and lower molds. The present invention relates to a method for manufacturing a decorative resin molded product which is performed by an injection gate having a substantially triangular shape so as to reduce the diameter.

  According to the first aspect of the present invention, a decorative sheet is laid in the lower mold when the decorative resin molded product is manufactured, and the upper mold is lowered onto the lower mold, and the upper mold and the additional mold are added. Since the molded resin is injected between the decorative sheet and the resin molded product is molded, and the decorative sheet and the polymer are integrally formed, the injection molding process of the resin molded product and the decoration of the surface of the resin molded product are performed. Since the processes can be performed simultaneously in the same mold, it is possible to realize a remarkable process shortening, productivity improvement, and cost reduction.

  In addition to the first invention described above, the second invention is such that, in the injection molding process of the resin molded product, the injection of the molded resin between the upper mold and the decorative sheet is performed on the injection side inner diameter of the upper and lower molds. Since it is performed by a wide injection gate having an opening inner diameter width of at least a half or more, the flow of the injection resin flows smoothly and evenly. As a result, partial wrinkles are unlikely to occur and the surface property is improved. A decorative resin molded product can be obtained.

  Further, in the third invention, in addition to the above-mentioned second invention, the injection of the molded resin between the upper mold and the decorative sheet in the injection molding process of the molded resin is performed on the injection side inner diameter of the upper and lower molds. The inner diameter width is gradually reduced from the opening to a position separated from the opening by a distance of at least one-half to one-third of the injection-side inner diameter of the upper and lower molds. Since the injection gate is formed in a substantially triangular shape so as to have a diameter, the flow of the injection resin flows smoothly and evenly, and turbulence does not occur in the flow process. A resin molded product can be obtained.

  The specific contents of the present invention will be described below based on the illustrated embodiment. In the figure, 10 is a decorative sheet, 13 is an injection mold, and 16 is an injection gate. The decorative sheet 10 is a relatively thin sheet for covering the surface of the resin molded product to give a decorative property, and as shown in FIG. 1, a base resin layer 11 attached to the surface of the resin molded product, The decorative layer 12 applied on the base resin layer 11 is composed of a metal layer.

  The decorative sheet 10 in FIG. 1 shows the simplest configuration, and includes a base resin layer 11 / decorative layer 12 / transparent protective layer (not shown). Or, the decorative layer 12 is a comparatively thin or translucent colorant, or is provided with a pearl pigment, or the base resin layer 11 is mixed with a rutile pearl pigment, or the decorative layer 12 Various variations are possible, such as those printed between the two.

  Even when a metal layer is used as the decorative layer 12, metal deposition is performed through a deposition anchor layer using an acrylic, urethane, vinyl, or cellulose resin, or a sputtering method or an ion plating method. It can be formed by known means. In this case, the vapor deposition can be performed by vacuum vapor deposition or electron beam emission. As the metal to be used, Cr is the best because of its low cost, but in addition, a simple substance such as Sn, In, Al, Ni, Ag, Au, or a compound thereof may be used. Furthermore, the case where a decorating sheet is a laminated body of decorating films, such as a base resin adhesion layer and a coating-film layer or a metal layer, etc. are also considered. As a decorative sheet having such metallic luster, Dainippon Ink Chemical Co., Ltd. trade name “Metalare” is used.

  Furthermore, as the base resin layer 11, various thermoplastic resins such as acrylonitrile, styrene, butadiene, enka vinyl, polypropylene, polycarbonate, or a mixture thereof are generally used.

  As shown in FIG. 2, the injection mold 13 includes a concave lower mold 14 and a convex upper mold 15 to form a pair of injection molds 13. Further, the injection gate 16 has an opening at the front end of the injection port for injecting the resin between the upper mold 15 and the decorative sheet 10 laid in advance in the lower mold 14 in the lateral direction of the upper and lower molds 15 and 14. It faces in a pair of molds.

  Further, the opening inner diameter width b of the tip opening portion depends on the thickness of the resin molding 17 to be molded, but is usually at least about 1.5 to 3.0 mm for the upper and lower molds 15 and 14. At least about half of the injection-side inner diameter a is sufficient, and if it is 3.0 mm or more, it is two-thirds or more of the injection-side inner diameter a of the upper and lower molds 15 and 14 depending on the thickness. If the inside diameter of the opening is not set, turbulent flow is likely to occur during resin injection. Therefore, it is necessary to be at least one half or more of the injection side inner diameter a of the upper and lower molds 15 and 14.

  Further, in order to prevent the flow of the injection resin from flowing smoothly and evenly and to prevent further turbulence in the flow process, the shape of the injection gate 16 toward the opening of the injection gate 16 described above is shown in FIG. As shown in FIG. 3, a substantially triangular shape is formed so that the inner diameter width gradually decreases from the opening to a position separated by a distance of at least one half to one third of the injection side inner diameter a of the upper and lower molds 15 and 14. Is preferable. In this case, as the resin for molding the resin molded product 17 to be injected, many types of general-purpose resins are used.

  In the configuration of the above-described embodiment, the decorative sheet 10 is laid in the lower mold 14 with the surface side (decorative layer 12 side) facing down, and the upper mold 15 is lowered on the lower mold 14. The molded product resin 17 is injected between the upper mold 15 and the decorative sheet 10 and solidified in a state of being integrally molded with the decorative sheet.

  When the molded resin 17 is injected, since the injection gate 16 has an opening inner diameter width that is at least one half of the injection side inner diameter of the upper and lower molds, almost no turbulent flow of the resin occurs during the injection. Further, the shape of the injection gate 16 has an opening inner diameter width of at least one-half of the injection-side inner diameter of the upper and lower molds, and at least one-half to one-third of the injection-side inner diameter of the upper and lower molds from the opening. In the case where it is performed by an injection gate having a substantially triangular shape so that the inner diameter width is gradually reduced toward a position separated by a distance of 1, there is no turbulent flow at the time of resin injection, and even better surface properties Can be obtained.

The fragmentary sectional view showing an example of the decorating sheet used in this invention. The schematic sectional drawing of the injection mold used for implementation of this invention. The top view showing the state of the resin molding which gave the decorating sheet in FIG. 2, and the injection gate. The top view showing the surface of the injection-molding die conventionally used widely and the decorative resin molded product molded by the die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Decorating sheet 11 Base resin layer 12 Decorating layer 13 Injection mold 14 Lower mold 15 Upper mold 16 Injection gate 17 Molded resin

Claims (4)

  A decorative sheet is laid in the lower mold with the front side down, and the upper mold is lowered onto the lower mold, and a resin molded product is injected between the upper mold and the decorative sheet. A method for producing a decorative resin molded product which is integrally formed with the decorative sheet by polymerization.   A decorative sheet is laid in the lower mold with the front side down, and the upper mold is lowered onto the lower mold, and a molded resin is injected between the upper mold and the decorative sheet. In the case where a resin molded product is molded and polymerized integrally with the decorative sheet, the injection of the molded product resin between the upper mold and the decorative sheet is at least two minutes of the injection side inner diameter of the upper and lower molds. A method for producing a decorative resin molded product, which is performed by an injection gate having an opening inner diameter width of one or more.   A decorative sheet is laid in the lower mold with the front side down, and the upper mold is lowered onto the lower mold, and a molded resin is injected between the upper mold and the decorative sheet. In the case where a resin molded product is molded and polymerized integrally with the decorative sheet, the injection of the molded product resin between the upper mold and the decorative sheet is at least two minutes of the injection side inner diameter of the upper and lower molds. It has an opening inner diameter width of 1 or more, and is substantially triangular so that the inner diameter width gradually decreases from the opening portion to a position separated by at least one half to one third of the injection side inner diameter of the upper and lower molds. A method for producing a decorative resin molded product, which is performed by a shaped injection gate.   The method for producing a decorated resin molded article according to any one of claims 1 to 3, wherein the decorative sheet is a laminate of a base resin adhesion layer and a decorative film such as a coating layer or a metal layer.

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