JP3414235B2 - Molding method for resin molded products - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a molding method for a resin molded article such as an instrument panel of an automobile, in which a skin is partially disposed integrally.

[0002]

2. Description of the Related Art For automobile instrument panels, door trims, etc., resin molded products made of synthetic resin are used. However, in consideration of the physical characteristics of the surface, surface appearance, etc. It is arranged. Then, as shown in FIG. 9, for example, such a resin molded product 9 partially having a skin has a resin portion 91 as a main body made of synthetic resin and a skin 95 integrally molded on a part thereof. Become.

As the skin 95, for example, there is one having vinyl chloride on the front side and a polypropylene foam layer on the back side. In the conventional resin molded product, a skin is arranged on a part of the inner wall of the cavity of the molding die, and the gate 8 (FIG. 9) directs the skin 95 toward the skin.
Molding is performed by injecting synthetic resin into the cavity of the mold.

[0004]

However, in the resin molded product 9 molded by the above method, as shown in FIG. 9, the synthetic resin 91 wraps around to the surface side of the end portion of the outer skin 95, and the wraparound resin portion 910. May be formed. Therefore, the appearance of the resin molded product 9 deteriorates.

In view of the above-mentioned conventional problems, the present invention does not form a wraparound resin portion on the surface side of the skin,
An object of the present invention is to provide a method for molding a resin molded product having excellent surface appearance.

[0006]

According to a first aspect of the present invention, there is provided a resin molded product, wherein a skin is disposed on a part of an inner wall of a molding die, a synthetic resin is injected into a cavity of the molding die, and the skin is partially provided. In the method of integrally molding, a first gate is provided on a first inner wall portion located on a portion other than the back surface side of the outer skin arranged on the inner wall of the molding die, and a second gate located on the back surface side of the outer skin arranged on the inner wall. using a mold having a second gate to the inner wall portion, first, an injection Then the synthetic resin to the tip portion of the synthetic resin from the first gate has reached near the end of the skin
Together, the first gate is closed and the synthetic tree from the first gate is closed.
A method for molding a resin molded product is characterized in that the injection of oil is stopped and then the synthetic resin is injected from the second gate.

What is most noticeable in the present invention is that when the synthetic resin is injected, the synthetic resin is first injected from the first gate until the tip of the synthetic resin reaches near the end of the skin . Close the gate to the first gate
The injection of the synthetic resin from is stopped, and then the synthetic resin is injected from the second gate.

Next, the function and effect of the present invention will be described. In the present invention, as described above, the skin is arranged on a part of the inner wall of the mold, and after the mold is clamped, the synthetic resin is injected from the first gate. Then, the synthetic resin is injected until the tip of this synthetic resin reaches near the end of the skin ,
1 Close the gate .

Then, before the tip of the synthetic resin from the first gate reaches the edge of the skin, the second gate
A synthetic resin is injected from the gate. This injection is performed toward the back side of the epidermis. Then, the synthetic resin passes through between the back surface side of the skin and the inner wall of the molding die, proceeds toward the end of the skin, and the front end portion of the synthetic resin from the first gate located in front of the end. Fused and united with.

What is important here is that since the synthetic resin injected from the second gate is injected to the back surface side of the outer skin, it advances while pressing the outer skin toward the inner wall of the molding die. . Therefore, the end portion of the epidermis is also pressed inward of the inner wall, and the synthetic resin is prevented from wrapping around from the end portion to the surface side of the epidermis. Further, the synthetic resin injected from the first gate has its tip portion reaching just before the end portion of the epidermis, so that the wraparound is not performed. Therefore, the obtained resin molded product has excellent surface appearance even on the surface side of the skin.

Next, according to the invention of claim 2, the first
It is preferable to stop the injection of the synthetic resin injected from the gate when the distance between the tip portion of the gate and the edge of the skin is 0 to 10 cm.

When the distance between the tip of the synthetic resin and the end of the skin is less than 0 cm, that is, when the tip of the injected synthetic resin comes inside the end of the skin, The wraparound resin portion may be slightly generated. On the other hand, if it exceeds 10 cm, the distance between the end of the epidermis and the tip of the synthetic resin from the first gate becomes far,
The amount of synthetic resin that fills the cavity in the meantime with the synthetic resin from the second gate increases, and the injection molding time increases. Because the clearance between the back surface side of the skin and the inner wall of the resin molded product is small, the traveling speed of the synthetic resin injected from the second gate is slow. Therefore, if the amount of the above-mentioned synthetic resin to be supplemented increases, the time required for the entire injection molding will increase. In addition, since the synthetic resin associates at the site away from the edge of the epidermis, the weld becomes conspicuous.

Next, according to the invention of claim 3, the first
It is preferable that a plurality of gates and a plurality of second gates are provided on the first inner wall portion and the second inner wall portion, respectively. In this case, the synthetic resin injected from the plurality of second gates presses the back surface side of the skin from a plurality of positions. Therefore, the formation of the wraparound resin portion can be further prevented. Moreover, the synthetic resin can be injected into the resin portion in a short time.

Next, according to the invention of claim 4, the second
After injecting the synthetic resin from the gate, it is preferable to continuously hold the pressure of the molded product by the second gate. In this case, the synthetic resin is first injected through the first gate,
The gate is closed, then the second gate is used to inject the synthetic resin, and then the second gate is used to maintain the pressure. Therefore, the pressure is relieved by the skin, and some time elapses until the holding pressure is applied to the non-skin molded product side. Therefore, the generation of burrs can be suppressed.

Next, according to the invention of claim 5, the second
It is preferable that after the synthetic resin is injected through the gate, the second gate is closed and then the first gate is opened to hold the molded product. In this case, first the synthetic resin is injected from the first gate, then the first gate is closed, then the synthetic resin is injected from the second gate, then the second gate is closed, and then the first gate is opened again. To maintain the pressure. That is, after injecting the synthetic resin from the second gate, the first gate is opened again to carry out the holding pressure, so that some time elapses until the holding pressure is applied to the non-skin portion molded article side. Therefore, the occurrence of burrs is suppressed.

The present invention can be utilized for molding instrument panels, door trims, console boxes, console lids, etc. of automobiles.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1 A molding method of a resin molded product having a partial skin according to an embodiment of the present invention will be described with reference to FIGS. In the molding method of this example, the first gate 11 is provided on the first inner wall portion 101 located on a portion other than the back surface side 22 of the outer skin 2 arranged on the inner wall 10 of the molding die 1, while the back surface side 22 of the outer skin 2 is provided. The second gate 1 is located on the second inner wall portion 102.
The molding die 1 provided with 2 is used.

In molding, first, as shown in FIG. 1, a synthetic resin 31 is injected from the first gate 11, and a tip portion 310 of the synthetic resin 31 is 0 to 10 cm from the end portion 25 of the skin 2. The first gate is closed when the position is reached. Then, as shown in FIG. 2, a synthetic resin 31 is injected from the second gate 12, and the second gate 12 is further injected.
Hold pressure with open. As a result, as shown in FIG. 3, the two synthetic resins 31 described above are fused and integrated, and a resin molded product partially having the skin 2 is obtained.

In this example, the surface 2 of the skin 2 is arranged so that its surface side 21 is in contact with the inner wall 10 of the mold. Such arrangement is performed by means of temporary fixing with a pin, vacuum suction using a suction device, or the like. Further, a second cavity 32 is formed between the back surface side 22 of the skin 2 and the second inner wall portion 102. A cavity 15 is formed between the inner wall 10 of the mold and the first inner wall portion 101.

Next, the function and effect of this example will be described.
In this example, as described above, the skin 2 is arranged on a part of the inner wall of the mold 1, and after the mold is clamped, the first gate 11 is removed.
More synthetic resin 31 is injected. And this synthetic resin 3
The tip part 310 of 1 is 0 to 10c from the end 25 of the epidermis 2.
The first gate is closed when the m position is reached. And
Then, before the tip portion of the synthetic resin 31 from the first gate 11 reaches the end portion 25 of the skin 2, the synthetic resin 31 is injected from the second gate 12. This injection is the skin 2
To the back side 22 of the.

Then, the synthetic resin 31 passes through between the back surface side 22 of the skin 2 and the second inner wall portion 102 of the molding die and advances toward the end portion 25 of the skin 2 and is more than the end portion 25. The tip portion 310 of the synthetic resin 31 from the first gate 11 on the front side is fused and integrated. Then, the holding pressure is continuously applied with the second gate 12 kept open.

What is important here is that the synthetic resin 31 injected from the second gate 12 is injected to the back surface side 22 of the skin 2, so that the skin 2 is formed on the inner wall 10 of the mold.
It is to push in the direction of. Therefore, the end portion 25 of the outer skin 2 is also pressed inwardly of the inner wall 10, and the synthetic resin 31 is prevented from flowing from this end portion to the surface side of the outer skin 2. Further, in the synthetic resin 31 injected from the first gate 11, the tip portion 310 thereof is the end portion 2 of the skin 2.
Since it has reached only before 5, the above wraparound is not performed. Therefore, the obtained resin molded product has excellent surface appearance even on the front surface side 21 of the skin 2.

Further, in the case of this embodiment, the synthetic resin is first injected from the first gate 11, the first gate 11 is closed, and then the synthetic resin 31 is injected from the second gate 12, and then the second resin is injected. Pressure is maintained by the gate 12. Therefore, the pressure is relieved by the skin 2, and some time elapses until the holding pressure is applied to the non-skin molded article side. Therefore, the generation of burrs can be suppressed. Therefore, it is possible to perform molding at a lower pressure than ordinary injection molding.

Embodiment 2 As shown in FIGS. 4 to 6, this embodiment shows an example in which the present invention is applied to an instrument panel 4 of an automobile. The instrument panel 4, as shown in FIGS. 4 and 5,
The whole has a resin portion 3 molded of synthetic resin,
A skin 2 is provided on the upper surface of the instrument panel.

In this example, as shown in FIG. 5, a plurality of first gates 111 and 112 and a plurality of second gates 12 are provided.
1, 122 is used. As the skin, as shown in FIG. 6, a three-layer skin in which vinyl chloride is provided as the surface layer 201, a polypropylene foam layer is provided as the inner layer 202, and polypropylene resin is provided as the base material 203 is used. Further, polypropylene is used as the synthetic resin of the resin portion 3.

In molding the instrument panel 4, the skin 2 is arranged on a part of the inner wall of the molding die as in the first embodiment, and the plurality of first gates 111 and 112 are formed.
Similarly to the first embodiment, the synthetic resin is sequentially injected from the second gates 121 and 122.

In this example, the injection of the synthetic resin from the first gate is stopped when the tip portion 31 of the synthetic resin reaches 2 mm before the end of the skin 2, and then the second gate is opened. It was The pressure holding by the second gate was performed for 15 to 20 seconds. Others are the same as those in the first embodiment. According to this example, there is no resin portion that wraps around the surface of the skin 2.
It is possible to obtain an instrument panel having excellent surface appearance.

Embodiment 3 As shown in FIGS. 7 and 8, this embodiment shows an example in which the present invention is applied to an automobile door trim. As shown in both figures, the door trim has a resin portion 30 which is wholly molded of synthetic resin, and a skin 20 is provided on a part thereof. In the figure, reference numeral 451 denotes an armrest, 45
2 is a speaker box, and 453 is a pocket.

A cloth having a polypropylene sheet lined on the back side was used as the skin 20, and polypropylene was used as the synthetic resin. Further, a plurality of first gates 115 and 116 are used as the first gate, and a plurality of second gates 125 and 126 are used as the second gate. Others are the same as those in the second embodiment. According to this example, it is possible to obtain an instrument panel that does not have a resin portion that wraps around the surface of the skin 20 and that has excellent surface appearance.

Fourth Embodiment In this embodiment, a synthetic resin 31 is injected from the first gate 11, and when the distance between the tip portion 310 of the synthetic resin and the end portion 25 of the skin 2 reaches 0 to 10 mm, 1 gate 11 is closed, then synthetic resin 31 is injected from the second gate 12, the synthetic resin required for the molded product is filled, the second gate 12 is closed, and then the first gate is opened again and pressure is maintained. (See FIGS. 1 to 3). Otherwise, Embodiment 1
Is the same as.

In this case, first the synthetic resin is injected from the first gate 11, then the first gate 11 is closed, then the synthetic resin is injected from the second gate 12, and then the second resin is injected.
The gate is closed, and then the first gate 11 is opened again to maintain the pressure. That is, after injecting the synthetic resin from the second gate 12, the first gate 11 is opened again to hold the pressure, so that a certain amount of time elapses until the holding pressure is applied to the non-skin portion molded article side. Therefore, the occurrence of burrs is suppressed.

Further, since the holding pressure is performed by the first gate 11 on the non-epidermal side, no pressure is directly applied to the epidermis 2 for a long time. Therefore, the damage that the skin 2 is partially strongly compressed can be prevented. In addition, the same effect as that of the first embodiment can be obtained.

[0033]

According to the present invention, it is possible to provide a method for molding a resin molded article having excellent surface appearance without forming a wraparound resin portion on the surface side of the skin.

[Brief description of drawings]

FIG. 1 is an explanatory view of a molding method of a resin molded product in a first embodiment.

FIG. 2 is an explanatory view of a molding method of a resin molded product, following FIG.

FIG. 3 is an explanatory view following FIG. 2 of a molding method of a resin molded product.

FIG. 4 is an explanatory diagram of an instrument panel according to the second embodiment.

5 is a cross-sectional view taken along the line AA of FIG.

FIG. 6 is an explanatory view of a skin according to the second embodiment.

FIG. 7 is an explanatory view of a door trim in the third embodiment.

8 is a sectional view taken along the line BB of FIG.

FIG. 9 is an explanatory view showing a problem of a resin molded product in a conventional example.

[Explanation of symbols]

1. ． ． Mold, 10. ． ． inner wall, 101. ． ． The first inner wall portion, 102. ． ． The second inner wall portion, 11. ． ． 1st gate, 12. ． ． 2nd gate, 2. ． ． Epidermis, 21. ． ． Front side, 22. ． ． Back side, 4. ． ． Instrument panel, 45. ． ． Door trim,

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Atsushi Goto No. 1 Nagahata Ochiai, Kasuga-cho, Nishikasugai-gun, Aichi Prefecture Toyota Gosei Co., Ltd. Address within Toyoda Gosei Co., Ltd. (56) Reference JP-A-7-276421 (JP, A) JP-A-8-25407 (JP, A) JP-B 5-42936 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) B29C 45/00-45/84

Claims (5)

(57) [Claims] 1. A skin is arranged on a part of an inner wall of a molding die,
Inject the synthetic resin into the cavity of the mold to partially
In the method of integrally molding a resin molded product with a skin
hand, On the part other than the back side of the skin placed on the inner wall of the above mold
A first gate is provided on the located first inner wall portion, while
The second inner wall part located on the back side of the epidermis placed on the wall
Using a mold with two gates, First, from the first gate above, the tip of the synthetic resin is
Injection of synthetic resin until it reaches near the edge of the leatherAs well as
The first gate is closed and the synthetic resin is sprayed from the first gate.
To stop Then, a synthetic resin is injected from the second gate.
Molding method for resin molded products. 2. The synthetic resin injected from the first gate according to claim 1, wherein the injection is stopped when the distance between the tip portion of the first gate and the edge portion of the skin reaches 0 to 10 cm. A method for molding a resin molded product, which is characterized in that 3. The method for molding a resin molded product according to claim 1, wherein a plurality of the first gates and the second gates are provided on the first inner wall portion and the second inner wall portion, respectively. . 4. The resin molded product according to claim 1, wherein after the synthetic resin is injected from the second gate, the molded product is continuously held by the second gate. Molding method. 5. The molded article according to claim 1, wherein after the second gate is used to inject a synthetic resin, the second gate is closed, and then the first gate is opened. A method for molding a resin molded product, the method comprising: