JP4049685B2 - Molding method for partially decorated molded products - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a partially decorated molded product such as a vehicle instrument panel that is partially decorated with a decorative sheet, for example.
[0002]
[Prior art]
Conventionally, for example, a high-quality design has been applied to a part of the surface in order to give a high-quality appearance to the appearance of a resin product, to enhance cushioning, to improve the touch, etc. As a technique for molding such a resin molded product, for example, a decorative sheet is set in a mold and clamped, and then decorated. Start injection of molten resin from the injection injection hole of the mold where the sheet is not set toward the back of the decorative sheet, and then sequentially inject molten resin from the injection injection holes at other positions into the cavity. A method of filling and partially molding a partially decorated resin molded product, or as disclosed in Japanese Patent Application Laid-Open No. 9-267353, the mold is in a half-open state, and from the injection injection hole at a position facing the decorative sheet, to the back side of the decorative sheet Injecting molten resin A method of forming a partially decorated resin molded product by injecting molten resin from an injection injection hole at a position away from the outer edge of the decorative sheet and filling the entire cavity after spreading the mold while closing the mold Etc. are known.
[0003]
[Problems to be solved by the invention]
However, in the method of starting the injection injection of the molten resin from the injection injection hole at the position facing the decorative sheet directly to the decorative sheet as in the former, the high temperature molten resin is directly injected onto the back surface of the decorative sheet. Therefore, there is a problem that the decorative surface of the decorative sheet is crushed by the injection pressure, or the decorative sheet is stretched or torn due to the influence of the fluid pressure in the cavity. ) When the pressure inside the cavity is set to a pressure higher than that at the time of injection, the decorative sheet moves, the decorative surface is crushed, and the sheet is stretched.
Also, as in the latter case, if the mold is injected in a half-open state, injection pressure and fluid pressure can be reduced and various problems occurring in the decorative sheet can be suppressed, but the molten resin injected in the half-open state Since the curing speed and the curing timing of the molten resin injected after mold clamping are different, there is a problem that it may cause cracks, distortion, and the like due to a temperature difference.
[0004]
Therefore, in the present invention, when a decorative sheet is set in a mold and a molten resin is injected and produced to produce a partially decorated resin molded product, the decorative surface of the sheet is crushed due to injection pressure, fluid pressure in the cavity, and the like. It is intended to prevent the occurrence of defects in quality by preventing problems such as the movement, stretching, and tearing of sheets.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention sets a decorative sheet on the molding surface of one of the pair of molds, injects the molten resin into the cavity from the injection injection hole, In the method of forming a partially decorated molded article by applying the next pressure, the decorative sheet is set on the sheet setting surface of the first mold provided with the injection injection hole, and the 2 The molten resin is injected toward the mold, and then the molten resin is filled into the cavity through an in-mold runner or the like formed on the molding surface of the second mold in the vicinity of the sheet set surface, Before applying the secondary pressure, the molten resin of the in-mold runner was compressed toward the sheet set surface.
[0006]
Thus, if the molding surface of the first mold in which the injection injection hole is provided is a sheet set surface, and the molten resin is injected from the injection injection hole of the first mold toward the second mold, the molten resin Since it does not inject directly toward the decorative sheet, it is possible to suppress a problem that the decorative surface of the decorative sheet is crushed by the injection pressure or the sheet is easily stretched by heat.
Moreover, the molten resin on the front surface of the decorative sheet is provided by providing a runner in the mold that faces the sheet setting surface or in the periphery of the molding surface of the second mold, and the molten resin passes through the runner in the mold. The flow rate of the decorative sheet is reduced so as to suppress the movement of the decorative sheet and problems such as elongation.
[0007]
Here, as the in-mold runner, for example, when injecting molten resin, it is thicker than the thickness of the actual product shape so that the flow rate of the molten resin flowing in the cavity can be reduced Thus, it is not necessary to use the entire area facing the sheet setting surface as an in-mold runner, and may be a partial area of the region facing the sheet setting surface.
Then, before injecting the molten resin and before applying the secondary pressure, the molten resin of the in-mold runner is compressed toward the sheet set surface to return to the actual product shape wall thickness, The effect of (holding pressure) effectively acts on the resin in the in-mold runner so as not to cause sink marks or the like in the same part.
[0008]
Further, in the present invention, a plurality of the injection injection holes are provided in or near the sheet set surface and at a position away from the sheet set surface, and when applying a secondary pressure, in or near the sheet set surface. The injection injection hole was closed.
[0009]
Thus, if the injection injection hole in or near the sheet set surface is closed before applying the secondary pressure, for example, when applying a secondary pressure higher than the pressure at the time of injection, a large flow pressure is applied to the decorative sheet. It does not take place, and it becomes difficult to cause problems such as movement and elongation of the seat.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the accompanying drawings.
Here, FIG. 1 is an explanatory view of a molded instrument panel for a vehicle molded by the molding method according to the present invention, FIG. 2 is an explanatory view of an in-mold runner, and FIG. 3 is a state in which the molten resin of the in-mold runner is compressed. It is explanatory drawing.
[0011]
The molding method of the partially decorated molded product according to the present invention improves the designability, functionality, etc. on a part of the exterior surface and the like, for example, when injection molding the vehicle instrument panel 1 as shown in FIG. In the technique for integrating the decorative sheet 2 (hatched portion in the figure) for the purpose, to prevent adverse effects on the decorative sheet 2 due to the injection pressure of the molten resin, the fluid pressure when flowing in the cavity, etc. Thus, it is possible to prevent such a problem that the decorative surface of the decorative sheet 2 is crushed, the sheet 2 is moved, stretched or torn.
[0012]
Here, as the decorative sheet 2, for example, fiber materials such as woven fabric and non-woven fabric, thermoplastic resin sheets such as TPO (olefin resin), vinyl chloride, and polyurethane, or foamed resin sheets can be applied. In the embodiment, a TPO sheet is used.
In addition, as the injection resin, for example, resin materials commonly used for injection molding such as polyethylene, polypropylene, polystyrene, polyamide, acrylonitrile-styrene-butadiene copolymer, ethylene-propylene block copolymer are applied. Is possible.
[0013]
Then, the resin injection portion of such instrument panel 1 are provided at a plurality of locations of _G 1 ~G ₉ in Figure, the upper injection unit _G 1 ~G ₃ and below the injection part _G 7 ~G ₉ Is provided at a position away from the decorative sheet 2, and the intermediate injection parts G _{4 to} G ₆ are provided in the sheet surface of the decorative sheet 2.
[0014]
Then, the shaping | molding method of the instrument panel 1 is demonstrated based on FIG. 2, FIG.
First, among the pair of first and second molds 11 and 12 shown in FIG. 3, the decorative sheet 2 is mounted on the molding surface of the first mold 11 provided with the nozzle 13 and the sprue 14 as injection injection holes. . Here, means for fixing the decorative sheet 2 and the like are arbitrary. For example, a locking portion where a part of the decorative sheet 2 is locked is formed on the molding surface of the first mold 11. Or may be fixed by other methods. And the molding surface part of the 1st metal mold | die 11 with which this decorating sheet 2 is mounted | worn is called sheet set surface 11s.
[0015]
In addition, a hole 2h is formed in the decorative sheet 2 in advance at a position corresponding to the position of the sprue 14, and the hole 2h is set in accordance with the position of the sprue 14 to be injected from the sprue 14. The molten resin is injected toward the opposing second mold 12 through the hole 2h.
[0016]
On the other hand, the second mold 12 is provided with a land portion 12n at a position facing the opening of the sprue 14, and at a position facing the sheet setting surface 11s, a recess for forming the in-mold runner r. 12d and a slide plate 15 are provided.
Then, when the slide plate 15 is retracted from the predetermined position, the thickness “a” of the cavity between the decorative sheet 2 spreads beyond the thickness “b” of the molded product, and the in-mold runner r is formed. By moving forward, the thickness of the cavity coincides with the thickness b of the molded product, and the in-mold runner r disappears.
[0017]
Then, after the decorative sheet 2 is mounted on the sheet set surface 11s of the first mold 11 as described above, the slide plate 15 of the second mold 12 is moved backward as shown in FIG. The mold is clamped with the inner runner r formed, and molten resin is injected into the cavity through the nozzle 13 and the sprue 14.
At this time, since the high-temperature and high-pressure molten resin is not directly injected toward the decorative sheet 2, there is no problem that the decorative surface of the decorative sheet 2 is crushed, and it is easily stretched by heat. Such a tendency is suppressed.
Moreover, since it is desirable that the injected molten resin is first filled in the cavity on the front surface of the decorative sheet 2, in the molding method of the instrument panel 1 shown in FIG. 1, the resin injection portions G _{1 to} G The injection order of _{9 is} the order of G ₄ , G ₅ → G ₆ → G ₁ , G ₂ , G ₃ → G ₇ , G ₈ , G ₉ .
[0018]
First, the molten resin injected from the resin injection parts G ₄ and G ₅ is filled in the cavity on the front surface of the decorative sheet 2. At this time, as shown in FIG. filled through r. And the flow rate of the molten resin which passes the in-mold runner r is lowered, and the malfunction that the decorating sheet 2 moves or is extended is suppressed.
[0019]
Then, after that, when the molten resin is injected from each resin injection portion G ₆ , G ₁ , G ₂ , G ₃ , G ₇ , G ₈ , G ₉ and all the inside of the cavity is filled with the molten resin, Before applying pressure (holding pressure), the slide plate 15 is advanced, and the molten resin of the in-mold runner r is compressed toward the decorative sheet 2 as shown in FIG. Is the thickness b of the molded product.
Here, in the case where the resin of the in-mold runner r is not compressed by the slide plate 15, the same part becomes too thick, and the effect of the subsequent secondary pressure is not exerted. Become.
[0020]
Then, before subjecting the secondary pressure, so as to close the resin injection portion _{G 4, G 5, G 6} of the decorative sheet 2 plane, from these injection unit _{G 4, G 5, G 6} is closed two Apply the next pressure.
Then, a big fluid pressure is not applied to the decorating sheet 2, and it becomes difficult to raise | generate malfunctions, such as a movement of the decorating sheet 2, and elongation.
[0021]
By the way, the side gate groove m as shown in FIG. 2 is provided in the land portion 12n of the second mold 12, and the molten resin injected from the sprue 14 is filled in the cavity on the front surface of the decorative sheet 2. It is also effective to promote it.
Thus, if it is made to accelerate | stimulate that molten resin is filled in the cavity of the front surface of the decorating sheet 2, the decorating sheet 2 can be hold | maintained in a fixed position, and defects, such as position shift, can be suppressed further and is suitable. It is.
[0022]
The present invention is not limited to the above embodiment. What has substantially the same configuration as the matters described in the claims of the present invention and exhibits the same operational effects belongs to the technical scope of the present invention.
For example, the molded product is not limited to the instrument panel, and may be other products, and the resin injecting portions G _{4 to} G ₆ are not limited to being provided in the sheet surface of the decorative sheet 2. Even when it is provided in the vicinity of the decorative sheet 2, it can be similarly applied.
[0023]
【The invention's effect】
As described above, the molding method of the partially decorated molded product according to the present invention sets the decorative sheet set in advance in the mold to the mold provided with the injection injection hole, and molds the mold on the opposite side. After forming the in-mold runner on the surface and injecting the molten resin, the molten resin of the in-mold runner is compressed toward the sheet set surface before applying the secondary pressure. Problems such as deviation, elongation, and tearing can be suppressed.
Further, when the secondary pressure is applied, if the injection injection hole in or near the sheet set surface is closed, it is possible to further suppress problems such as misalignment and elongation of the sheet.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a molded instrument panel for a vehicle molded by the molding method according to the present invention. FIG. 2 is an explanatory diagram of an in-mold runner. FIG. 3 is an explanatory diagram of a state in which the molten resin of the in-mold runner is compressed. (A) is a state diagram before compression, (b) is a state diagram after compression.
1 ... instrument panel, 2 ... decorative sheet, 11 ... first mold, 11s ... sheet set surface, 12 ... second mold 14 ... sprue, r ... mold _{runner, G} 1 ~G 9 _... resin injection Department.

Claims (2)

Set the decorative sheet only on the molding surface of one of the pair of molds, inject the molten resin into the cavity from the injection injection hole, and then apply the secondary pressure to partially apply A method of forming a decorated molded product, the step of setting the decorative sheet on a sheet set surface of a first mold provided with an injection injection hole, and facing the sheet set surface from the injection injection hole second after injecting the molten resin toward a die, the opposite to the sheet set surface or a cavity molten resin through a mold runner which is formed on the molding surface of the second mold around the to comprising a step of filling all, a step of compressing toward the sheet set face the mold in a runner of molten resin before applying the secondary pressure even after filling the molten resin into all of the cavity of the Partial decoration featured by Molding method of goods.   A plurality of the injection injection holes are provided in or near the sheet set surface and at a position away from the sheet set surface, and when applying the secondary pressure, injection injection in or near the sheet set surface is performed. The method for forming a partially decorated molded product according to claim 1, wherein the hole is closed.

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