JP2000254930A - Manufacture of synthetic resin molding by powder slush molding process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the emboss transfer of a mold face and thereby prevent pin holes, voids or the like from being generated to manufacture a high-quality product by closely binding a power slush molding die and a power box together and create a vacuum state temporarily in the molding die during melting a molding material on a mold face to discharge gas in the molding material and between the material and the mold face. SOLUTION: A mold face 2 is heated using heaters 4 around the periphery of a powder slush(PS) molding die 1 and the opening part 3 of the molding die 1 is airtightly sealed with the help of a sealing member 6 on a powder box (PS) 5 storing a PS molding material 11. The molding die 1 and the PB 5 set in a combined state are reversely turned upside down and further, are given a rotating motion in such a way that the die 1 and the PB 5 are alternately rocked to the right and the left. Thus the PS molding material 11 sticks to the mold face 2 of the molding die 1 and is thermally molted to form a molten resin layer on the mold face 2. Next, the interior of the molding die 1 and the PB 5 is set in a vacuum state using a vacuum device 9 to discharge air between the molten resin layer and the mold face 2 and trapped in the molten resin layer. The resin is set by cooling into a molding. Consequently, it is possible to prevent voids, pin holes or the like from being generated and form an emboss with high clarity to obtain the molding of a superb quality.

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 a synthetic resin molded product for producing a skin such as an instrument panel, which is an interior part for an automobile, by using a powder slush molding method. The present invention relates to a method for producing a synthetic resin molded product by a powder slush molding method for obtaining a high quality skin or the like by suppressing the occurrence of the like.

[0002]

2. Description of the Related Art Conventionally, a well-known powder slush molding method is employed to form a synthetic resin molded product used as a skin of an instrument panel, a door trim, a glove box, etc., for example, as interior parts of an automobile. For example, PVC (TPVC), TP, and the like are placed on a mold surface in a mold having a predetermined shape heated to a temperature at which a powder slush molding material (powder-like synthetic resin) is softened and melted easily.
U, TEO (TPO), TPEE (TEEE) and other powder slash materials are adhered and fused to a desired thickness, and then the mold is cooled to form a molded product (skin) adhered to the mold surface. ) Is cooled and released from the mold surface to obtain a synthetic resin molded product such as a skin.

[0003] That is, a mold generally used for powder slush molding, which is generally performed in the past, includes a mold heated to a desired temperature and a powder box attached to an opening of the mold. First, a mold is placed on the powder box in which the powder slush molding material is placed, and then the mold is heated to a predetermined temperature, and then the mold and the powder box are rotated so that they alternately reverse. Then, the powder slush molding material is melt-adhered to the entire surface of the mold surface at a desired thickness on the mold surface of the mold.

[0004]

However, inside the powder box and the mold in which the powder box and the mold are adhered, air mixed in the powder slush molding material and the powder mixed with the powder slush molding material. Gas generated during the heating and melting of the slush molding material traps gas inside the molded synthetic resin product (skin), causing pinholes and voids, or the mold surface and the synthetic resin molded product There is a problem that the grain pattern formed on the mold surface may not be transferred well on the surface of the synthetic resin molded product due to air interposed between the molds.

The present invention has been made in view of such a conventional fact. In forming a synthetic resin molded article such as the above-mentioned skin by employing a powder slush molding method, the present invention has been applied to a method in which a mold is formed on a mold surface in advance. It is an object of the present invention to improve grain transfer corresponding to grain that is present, and to produce a high-quality synthetic resin molded article without causing bad phenomena such as pinholes and voids.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a powder box containing a powder slush molding material is placed over an opening of a heated powder slush molding die. In a powder slush molding method for inverting a powder slush molding die and a powder box to cause the powder slush molding material in the powder box to melt and adhere to the mold surface of the heated powder slush molding die, the powder slush molding die and the powder box And is hermetically bonded so that when the mold surface of the powder slush molding material is melted,
A method for manufacturing a synthetic resin molded product by a powder slush molding method in which a powder slush molding material and a gas contained between the powder slush molding material and the mold surface are temporarily evacuated to a vacuum state in the powder slush molding mold. It is characterized by having.

According to a second aspect of the present invention, a powder box containing a powder slush molding material is placed over an opening of the heated powder slush molding die, and then the powder slush molding die and the powder box are turned over. In the powder slush molding method of melting and adhering the powder slush molding material to the mold surface of the heated powder slush molding die, the powder slush molding die and the powder box are hermetically connected to form a mold surface of the powder slush molding material. At the time of melting, the inside of the powder slush molding mold is temporarily brought into a vacuum state to discharge the powder slush molding material and the gas contained between the powder slush material and the mold surface, and then the powder slush molding mold is temporarily evacuated. In a compressed air state It is characterized by a method for producing a synthetic resin molded article according to powder slush molding method in which pressurized mold surface the molten material.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

1 and 2, reference numeral 1 denotes a mold used for powder slush molding. The mold 1 has a mold surface 2 formed in a concave shape and an opening 3 thereof. . As the material of the mold 1, a metal having good thermal conductivity can be selected and used, and for example, nickel, copper, aluminum, iron or the like is desirably used. Reference numeral 4 denotes a heater for heating the mold 1.

Reference numeral 5 denotes a powder box which is hermetically attached to the periphery of the opening 3 of the mold 1 via a sealing material 6. The powder box 5 communicates with the inside and outside of the powder box 5. Both the vacuum device 9 and the compressed air device 10 are connected to the end of the trachea 7 via a switching valve 8.

The schematic structure of the molding apparatus used in the powder slush molding method of the present invention is as described above. Next, a method for producing a synthetic resin molded article using the molding apparatus will be described.

First, the heater 4 disposed around the powder slush molding die 1 causes the die surface 2 of the die 1 to be, for example, PVC (TPVC), TPU, TEO (T
PO), TPEE (TEEE) or the like is heated to a temperature suitable for melting the powder slush molding material 11.
Next, the opening 3 of the mold 1 is air-tightly adhered to the powder box 5 containing the powder slush molding material 11 via the seal member 6. After that, the mold 1 and the powder box 5 are combined with each other, and are turned upside down, and a rotation operation such as swinging the left and right sides appropriately is added. By this rotation operation, when the mold 1 is positioned below the powder box 5 as shown in FIG. 2, the powder slush molding material 11 in the powder box 5 adheres to the mold surface 2 of the mold 1, At this time, the powder slush molding material 11 which has been heated on the mold surface is heated and melted and welded to the mold surface.

When the above-described rotation is applied to the powder box 5 and the mold 1, the amount of powder slush molding material adhered to the mold surface 2 gradually increases, and the molten resin having a desired thickness is formed on the mold surface 2. Layer 12 is formed. When the molten resin layer 12 is formed on the mold surface 2 in this manner, the vacuum device 9 is driven to make the mold 1 and the powder box 5 into a vacuum state. The air interposed therebetween or the air contained in the molten resin layer 12 is discharged to the outside of the mold 1.

In this way, the air in the mold 1 and the powder box 5 is exhausted, and the inside of the mold 1 and the powder box 5 becomes negative pressure, so that the molten resin layer 12 does not generate voids or pinholes. Air stagnation between the mold 12 and the mold surface 2 can be eliminated, and a high-quality molten resin layer 12 can be obtained.

After the molding of the molten resin layer 12 in which voids or pinholes are eliminated, the mold 1 is cooled, the molten resin layer 12 is cooled and solidified, and then the mold is opened. A resin molded product (skin) can be molded and released.

In the above embodiment, after the air in the mold 1 and the powder box 5 is exhausted, the molten resin layer 12
However, the present invention is not limited to this. For example, immediately after the air is discharged, the switching valve 8 is switched and the compressed air device is driven to supply the compressed air into the mold 1 and the powder box 5 to melt. The resin layer 12 is pressed against the mold surface 2. Therefore, when a grain shape or the like is formed on the mold surface 2, it is possible to clearly form a grain surface corresponding to the grain shape applied to the mold surface 2 on the surface of the molten resin layer 12 by the pressing action. it can.

In the embodiment shown in FIG. 3, the volume of the closed space closed by the mold 1 and the powder box is reduced, and the efficiency of discharging air and supplying compressed air inside the closed space is increased. It increases the productivity of the epidermis. That is, a powder box set in a shape that is positioned close to the mold surface 2 of the mold 1 (in this case, it is preferable to call it a closed frame)
By sealing the opening of the mold 1 with the sealing material 6 at 5, the volume in the mold 1 can be reduced, whereby the air in the mold space is discharged, or the compressed air is reduced. It is possible to save energy and shorten work time when supplying energy.

[0018]

As described above, according to the method of molding a synthetic resin molded article by the powder slush molding method of the present invention, the molded synthetic resin molded article has a high quality without voids or pinholes. Good synthetic resin molded products can be produced.

In the case of a synthetic resin molded article which forms a grain or the like on the synthetic resin molded article, a grain having a high definition can be formed corresponding to a grain mold.

[Brief description of the drawings]

FIG. 1 is a schematic view of a powder slush molding apparatus used in the present invention.

FIG. 2 is an explanatory view when a skin is formed by a powder slush forming apparatus used in the present invention.

FIG. 3 is an explanatory view showing another embodiment of the powder slush molding apparatus used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Die 2 ... Mold surface 3 ... Opening 4 ... Heater 5 ... Powder box 6 ... Sealing material 7 ... Trachea 8 ... Switching valve 9 ... Vacuum device 10 ... Compressed air device 11 ... Powder slush molding material 12 ... Molten resin layer

Claims (2)

[Claims] Claims 1. A powder box containing a powder slush molding material is placed over an opening of a heated powder slush molding die, and then the powder slush molding die and the powder box are turned over to form a powder slush molding in the powder box. In a powder slush molding method in which a material is melt-adhered to a mold surface of a heated powder slush molding die, the powder slush molding die and a powder box are hermetically bonded to each other when the mold surface of the powder slush molding material is melted. Synthesizing resin by a powder slush molding method, wherein the inside of the powder slush molding mold is temporarily evacuated to discharge the powder slush molding material and gas contained between the powder slush material and the mold surface. Product manufacturing method. 2. A powder box containing a powder slush molding material is placed over an opening of a heated powder slush molding die, and then the powder slush molding die and the powder box are turned over to form a powder slush in the powder box. In a powder slush molding method in which a material is melt-adhered to a mold surface of a heated powder slush molding die, the powder slush molding die and a powder box are hermetically bonded to each other when the mold surface of the powder slush molding material is melted. The inside of the powder slush mold is temporarily evacuated to discharge the powder slush molding material and gas contained between the powder slush material and the mold surface, and then the inside of the powder slush mold is temporarily compressed with air. State, and the molten material A method for producing a synthetic resin molded product by a powder slush molding method, which comprises applying pressure to a mold surface.