JP2000006185A - Manufacture of in-mold molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide in-mold moldings with decorative effects of three-dimensional feel by using a mold whose one of molding halves has a recessed part for forming an annular projection formed in a region against the outer peripheral edge part of a finished product on the inner face of a cavity, and arranging a decorative film covering the recessed part and further filling the recessed part with a molten resin to form the annular projection integrally with the moldings. SOLUTION: A recessed part 5 for forming an annular projection to be provided on the face of a cavity in a mold is prepared for forming a fitting part such as a leg and a claw to be attached to another member. The dimensions and the cross section shape of the recessed part 5 are properly decided in accordance with moldings. A decorative film 4 is arranged in such a manner that it covers the recessed part 5, using the mold having the inner face of the cavity with the recessed part 5. Further the decorative film 4 is softened in the annular recessed part 5 by the pressure and heat of a molten resin 13 to be injected and cut off. The molten resin 13 is made to flow into the annular recessed part 5. Thus it is possible to integrate the resin moldings with the film 4 into a single piece and dispense with the cutting of the decorative film 4 in an after-fabrication and obtain the in-mold moldings with a resin part formed on the first surface and the decorative film layer 4 on the second surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an in-mold molded product in which a resin is integrated on a decorative film.

[0002]

2. Description of the Related Art It is conventionally known to arrange a film having a decorative pattern in a mold and inject a transparent resin onto the film to produce a film-integrated resin molded product. By this method, the picture is viewed through the transparent resin, and a decoration with a deep three-dimensional effect can be applied to the resin molded article in combination with the lens effect.

In this case, in order to attach the decorative molded article to another member, it is necessary to integrate mounting feet and claws into the molded article. Japanese Patent Application Laid-Open No. 7-276458 proposes such a problem. There is a method disclosed in the issue.
In this method, a molded product having a design on one surface made of a first resin is molded, and the molded product is placed in a female mold of an insert molding die so that the design faces a male mold. To obtain a molded product in which the pattern is sandwiched by the second resin molded portion. The attachment for the decorative molded product is formed by the second resin molded portion.

As another method, when a film having a decorative pattern is set in a mold and resin is injection-molded,
It is conceivable that a hole is previously provided in the film at a position corresponding to the mounting portion. Through this hole, the resin enters the concave portion for forming the mounting portion in the mold, and the mounting portion of the film-integrated resin molded product can be formed.

[0005]

However, in the former method, the molding step is inevitably performed in two steps, which is complicated and costly. In addition, in the latter method, in addition to impairing the appearance because a part of the decorative film is torn, in addition to the step of providing a hole in the film in advance,
In addition, this method also requires an operation of aligning the hole of the film with the concave portion of the mold for forming the mounting portion, and this method also increases the cost.

[0006] Under such circumstances, the present invention comprises a resin layer on the front side and a decorative film layer on the back side to provide a three-dimensional appearance.
It is an object of the present invention to provide a method of manufacturing an in-mold molded product having a deep decorative effect at low cost.

[0007]

As a result of intensive studies, the present inventor has used a mold having a recess for forming an annular projection at a portion of a mold cavity surface corresponding to a substantially outer peripheral edge of a molded product. By arranging the decorative film in the mold and performing injection molding, the film was cut by the heat and pressure of the injected molten resin, and it was found that a molded product excellent in design effect integrating the decorative film could be easily manufactured. This has led to the present invention.

That is, according to the present invention, a pair of molds each having a concave portion for forming an annular projection in a portion corresponding to a substantially outer peripheral portion of the product on the inner surface of the cavity is used. After arranging a decorative film so as to cover and closing a pair of molds, the cavity is filled with a molten resin to form a resin molded body, and at the same time, the resin is caused to flow into a concave portion for forming an annular protrusion, and a resin molded body is formed. The present invention relates to a method for manufacturing an in-mold molded product, wherein an annular projection is formed integrally at a substantially outer peripheral edge portion.

In the present invention, the recess for forming an annular projection provided on the surface of the mold cavity is for forming a locking portion such as a foot or a claw to be attached to another member, and its size or sectional shape is formed by molding. It is determined appropriately depending on the product. The position of the concave portion is on the decorative film surface side of the molded product, and is substantially at the outer peripheral edge of the molded product.

[0010] More preferably, it is a part slightly inside the outermost peripheral part. In the present invention, using a mold having a cavity inner surface provided with the annular projection concave portion,
The decorative film is arranged so as to cover the concave portion, and the decorative film is softened and cut in the annular concave portion by the pressure and heat of the injected molten resin, and the molten resin flows into the annular concave portion to integrate the resin formed body and the film. It is important that Other than that, there is no particular limitation, and a normal injection molding method can be applied.

Therefore, a thermoplastic resin can be used as the molding resin, but a transparent, translucent or pale colored material is preferable so that the decoration on the back side can be visually recognized. For example, an acrylic resin such as polymethyl methacrylate resin is used. Resin, polycarbonate, polyamide, polystyrene, ABS and the like can be mentioned. A compounding material may be appropriately added to these resins.

The decorative film used in the present invention is located on the back side of the above-mentioned transparent or translucent resin molded article, and enhances the design effect of the decoration and gives the molded article a sense of quality. This decorative film may be a continuous film or a single film, but a continuous film is preferable. The film has a pattern such as a character, a symbol, or a picture as a decorative portion.
This decorative portion may be on the entire surface of the film, or on the center or the like. As a material of the film, a film used in a general printing method capable of printing the above-described picture or the like can be used. For example, acrylic resins such as polymethyl methacrylate, polyester resins such as polyethylene terephthalate, polyvinyl chloride resins, polyamide resins, and polyolefin resins are preferred. The printing method is not particularly limited, and screen printing, gravure printing, silk printing, or the like is applied.

In the present invention, in order to bond and integrate the decorative film (or the printed layer thereon) and the resin molded article satisfactorily, it is preferable that both materials have compatibility.
However, the present invention is not limited to this combination. For a combination having poor compatibility, the film can be integrated via an adhesive such as providing an adhesive layer on the film. As described above, in the method of the present invention, the decorative film disposed on the mold cavity surface is softened by the pressure of the molten resin injected into the cavity, heat, and the other portion of the film in the annular concave portion of the cavity. Be separated. Therefore, in the method of the present invention, a decorative film, a molding resin,
The injection condition is selected. In one preferred example of the present invention, a decorative film having a printing layer of acrylic or vinyl ink on a polymethyl methacrylate film having a thickness of about 50 to 200 μm, and a polymethyl methacrylate resin as a molding resin. Use, resin temperature 170-270 ° C, injection pressure 700-1500kg
/ Cm ² under molding conditions.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of an ornament 2 in an airbag cover 1 which is an example of a resin molded product in which a decorative film according to the present invention is integrated with a back surface. FIG. 2 is an explanatory cross-sectional view taken along line A in FIG. As is clear from FIG. 2, the ornament (2), which is an in-mold molded product according to the present invention, has a decorative film (4) integrally on the back side at the center of the airbag cover, and has a substantially rear side. An annular projection (14) is provided at the outer peripheral edge.
For example, letters, symbols, pictures, patterns, and the like such as a company name and a car model name are printed on the decorative film 4, and the decorative film 4 is viewed through the transparent and translucent resin portion 3 on the front surface side. A deeper design can be brought out by the objective effect. In FIG. 2, the annular projection (14) functions as an attachment portion to the airbag cover. In this example, the annular projection (14) is attached to the stopper guide (7) on the airbag side by the stopper (6) (metal or metal). (A resin ring) and a welding stopper 14 for locking the ring. The welding stopper (14) may be formed by heat caulking, a push-on fix, or the like, or the shape of the welding stopper (14) may be formed into a seating surface or a hook for attaching a metal clip.

FIGS. 3 to 6 are process explanatory views of the in-mold molding method of the present invention.

FIG. 3 shows a state in which the decorative film (4) is supplied to the core mold (8) from a film feeder (not shown). FIG. 4 shows a state in which the mold is closed. FIG. 5 shows a state in which the resin is being injected. This shows a state in which the molten resin (13) fills the cavity, and at the same time, the decorative film is cut off by the heat and the resin pressure in the cavity-shaped annular concave portion (5) and the molten resin flows into the concave portion. FIG. 6 shows a completed state of filling the resin into the cavity. The separated end face of the separated decorative film is a mold-shaped annular concave portion (5).
Shows a state in which it has fallen inward.

FIG. 7 shows another embodiment, and explains a case where the part where the decorative film is cut off is made inconspicuous in the molded product. FIG. 7 (12) shows a case in which a process such as embossing is applied to a mold surface. The separation of the film is performed at the annular concave portion substantially at the outer peripheral edge of the molded product. Even if the film is originally damaged by the separation, it is not so noticeable, but further treatment is required.

FIG. 8 shows another embodiment of the decorative film used in the present invention. The decorative film is provided only on the portion (15) used as a decoration in the molded product, and the others are made of a transparent film. It has been left as it is. In this case, a weak portion of the film such as a slit may be provided on the outer periphery of the decorative portion to make it easier to separate the decorative portion.

FIG. 9 is an explanatory view showing a case where the decorative film is evacuated in the mold. The film can be adapted to the annular concave portion before the resin is injected. 10a and 10b show another embodiment of the locking portion of the annular projection, where a is a claw and b is a pin.

[0021]

As described above, according to the present invention, the decorative film is softened and cut off in the annular concave portion by the pressure and heat of the injected molten resin, and the molten resin flows into the annular concave portion. Since the molded body and the film can be integrated, and it is not necessary to cut the decorative film by post-processing, an in-mold molded product having a resin portion on the front side and a decorative film layer on the back side can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a perspective view of an airbag cover with an ornament according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line in FIG. 1A.

FIG. 3 is an explanatory view of the in-mold molding method of the present invention, showing a state where a decorative film is supplied to a core mold.

FIG. 4 is an explanatory view of the same, showing a mold closed state.

FIG. 5 is an explanatory view showing the state where the resin is injected into the cavity.

FIG. 6 is an explanatory view showing the state in which the filling of the resin into the cavity is completed.

FIG. 7 is an explanatory view of a mold obtained by graining a portion corresponding to an annular concave portion of a mold.

FIG. 8 is an explanatory view of an example of a decorative film used in the present invention.

FIG. 9 is an explanatory view of a state in which the decorative film is evacuated in the mold.

FIG. 10 is a diagram showing another embodiment of the locking portion of the annular projection.

Claims (1)

[Claims] 1. A mold having a pair of molds having an annular projection forming recess at a position corresponding to a substantially outer peripheral portion of a product in a cavity, wherein one of the molds covers the annular projection forming recess on the inner surface of the cavity. After the decorative film is placed on the mold and the pair of molds is closed, the cavity is filled with a molten resin to form a resin molded body, and at the same time, the resin is caused to flow into the concave portion for forming the annular projection to be integrally formed with the resin molded body. A method for producing an in-mold molded product, wherein an annular projection is formed on a substantially outer peripheral edge portion.