JPS62144913A - Molding device for powder slush - Google Patents

Abstract

PURPOSE:To prevent the generation of flashes by almost coinciding the surrounding wall of powder accommodating section in the bucket with the shape of outer circumference of product forming section of the molding tool and compressively adhering the sealing material to the outer circumference face of product forming section when the molding tool is clad. CONSTITUTION:Thermoplastic powder such as flexible vinyl chloride resin and the like is put into the powder accommodating section 22a of the bucket. The molding tool 24 is placed over the bucket 22 and closed with the clamp and the like. At that time, the molding tool 24 is heated up to normally 230-250 deg.C by the heating means 28. Next, the molding unit 20 is upside down and thermoplastic powder is moved into the molding tool 24. Since during the said process the product forming section (b) of molding tool 24 is encircled with the circumferential wall 23 and sealed with the sealing material 26, thermoplastic powder is not likely to adhere except the mold face 24a of the product forming section. Thermoplastic powder moved into the molding tool 24 is adhered on the mold face 24a because of the heat of mold face 24a to form up a molten film. A molding device 20 is placed back to the original normal position, and the surplus thermoplastic powder not used for forming the said molten film is accommodated in the powder accommodating section 22a and then the molding tool 24 is cooled down.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a powder slush molding apparatus used for molding a plastic skin material of a desired shape from thermoplastic plastic powder.

(Prior Art) Conventionally, plastic skin materials used for vehicle armrests and the like have been molded by various methods. Among them,
The powder slush molding method has recently attracted attention as a method for easily molding thin objects or objects having minute patterns, shapes, etc.

This powder slush molding method, as shown in FIG.
2 and a heatable mold (usually an electroforming mold) 14 having a product-shaped mold surface 14a. The molding of a plastic skin material using the molding device 16 is briefly described as follows.

First, the thermoplastic powder IO contained in the bucket 12 is moved into the mold 14, which has been heated in advance by a heating means 18 such as a heating medium circulation pipe, by turning the molding device 16 upside down, as shown in FIG. Molding mold 14
The thermoplastic plastic powder 10 that has moved inside is heated and melted by contacting the heated mold surface 14a, and becomes a molten coating 10a that conforms to the shape of the mold surface 14a.

Thereafter, by standing the molding device 16 upright, the surplus thermoplastic plastic powder that was not used to form the molten coating 10a is dumped into the bucket 1 again as shown in FIG.
Contained within 2. Then, if necessary, the mold 14 is further heated to completely melt and gel the molten coating 10a. Subsequently, the mold 14 is cooled, thereby hardening the molten coating 10a to fix its shape, and the desired plastic skin material is obtained by removing the cured coating from the mold.

(Problems to be Solved by the Invention) However, in the conventional molding device 16, since the powder accommodating portion 12a of the bucket 12 is larger than the product molding portion a of the mold 14, unnecessary pars are formed on the outer periphery of the product. It is formed. As a result, there is a problem in that a work to remove the paris is required and that raw materials are lost.

In addition, since the mold 14 only needs to heat the product molding part a, heating means 18 is provided outside the product molding part a in order to reduce heating energy and mold cost, and to make it lightweight.
Normally, this is not provided.

Therefore, the mold surface 14a of the mold 14 becomes lower in temperature as it goes outward from the product molding part a, and at the end of the part, a part made of thermoplastic plastic powder 100 in a semi-molten (commonly known as half-baked) state is formed. It will be done.

Since the half-baked part has insufficient gelation and has lower physical properties than the original, it may easily tear off from the product body and adhere to the mold when demolding the product. As a result, the deposits are mixed into the thermoplastic plastic powder 10 during the next molding, impeding the formation of a uniform film from the next time onwards, and causing deterioration of the physical properties of the resulting product.

The present invention has been made in view of the above-mentioned points, and provides a powder slush molding apparatus that solves the occurrence of flakes and various problems associated therewith.

(Means for Solving the Problems) The present invention provides a powder slush molding device comprising a bucket containing thermoplastic powder and a heatable mold attached to the bucket. The peripheral wall of the powder storage section is made to approximately match the outer peripheral shape of the product molding part of the mold, a sealing material is provided at the upper end of the peripheral wall, and the sealing material is crimped to the outer peripheral surface of the product molding part of the mold when the mold is attached. It is characterized by having a structure that allows

The sealing material is made of silicone rubber foam,
Moreover, it is preferable that the shape is hollow.

(Function) The peripheral wall of the powder storage part of the bucket is approximately aligned with the outer periphery of the product forming part of the mold, and a sealing material is provided at the upper end of the peripheral wall, so when the mold is attached to the bucket, the molding The outer periphery of the product forming part of the mold is sealed by the peripheral wall of the powder storage part of the bucket. Therefore, during molding of the plastic skin material (such as when the powder slush molding apparatus is inverted), the thermoplastic plastic powder will adhere only to the mold surface of the product molding part of the mold.

As a result, no particles are formed, so raw materials are not wasted, and there is no risk of particles in a half-baked state adhering to the mold and degrading the physical properties of the product, as in the conventional method.

In addition, if the sealing material is made of silicone rubber foam with excellent heat resistance, the sealing performance will not be impaired by the high temperatures during molding of the plastic skin material, and if it is made into a hollow shape,
The sealing material is easily deformed between the mold and the upper end of the peripheral wall, and good sealing performance can be obtained.

(Example) Next, this invention will be explained based on examples.

FIG. 1 is a cross-sectional view of a powder slush molding apparatus according to an embodiment of the present invention.

This molding device 20 consists of a bucket 22 and a mold 24.

The bucket 22 has a powder storage section 22a inside. The powder storage portion 22a is surrounded by a peripheral wall 23 that stands up from the inner bottom surface of the bucket.

The peripheral wall 23 has a shape that substantially matches the outer peripheral shape of the product molding part of the mold 24, and a sealing material 26 is provided at the upper end of the peripheral wall 23. The sealing material 26 is attached to the peripheral wall 2 shown in FIG.
As shown in the enlarged cross-sectional view of the main part of the upper part of 3, it is provided at the upper end of the peripheral wall 23 by fitting into a groove 23a formed at the upper end of the peripheral wall 23, or by screwing to the upper end of the peripheral wall. Further, it is preferable that the sealing material 26 is formed from a silicone rubber foam and has a hollow shape.

The molding die 24 is usually made up of a mold, and its inner surface is composed of a product molding part and an outer circumferential surface 24b of the product molding part. The product molding section has a mold surface 24a in the shape of a product.

Further, this mold 24 is provided with a heating means 28 such as a heating medium permeable pipe.

The mold 24 formed in this manner is placed over the bucket 22 and fixed to the bucket 22 with a clamp or the like during molding of the plastic skin material. At this time, the sealing material 26 at the upper end of the peripheral wall of the powder storage portion 22a is pressed against the outer peripheral surface 24b of the product forming portion of the mold, and the pressed portion is sealed.

Next, the molding of a plastic skin material performed using this molding apparatus 20 will be explained.

First, as shown in FIG. 3, the powder storage section 22a of the bucket is
Thermoplastic plastic powder 10, such as soft vinyl chloride resin powder, is added. And that bucket 2
A mold 24 is placed over the mold 2 and closed using a clamp or the like.

By this closing, the sealing material 26 on the peripheral wall of the powder storage portion
is pressed against the outer circumferential surface of the product molding part of the mold, and sealing is performed at the core part. At this time, the mold 24 is heated to a predetermined temperature, usually 230 to 250°C, by the heating means 28.

Subsequently, as shown in FIG. 4, the molding apparatus 20 is turned upside down, and the thermoplastic plastic powder IO is moved into the mold 24. At this time, since the product molding part of the mold 24 is surrounded by the peripheral wall 23 and sealed by the sealing material 26 as shown in FIG. There is no risk of adhesion. Then, the thermoplastic powder 10 that has moved into the mold 24 is moved to the mold surface 24 by the heat of the mold surface 24a.
4a to form a molten coating 10a. The thickness of the molten coating 10a can be adjusted by adjusting the length of time the molding device 20 is inverted.

After a predetermined period of time has elapsed, the molding device 20 is returned to its original upright position as shown in FIG. If necessary, the mold 24 is heated to completely melt (gel) the molten coating 10a, and then the mold 24 is cooled. With this cooling,
The molten coating is cured and has a fixed shape.

Thereafter, the cured film is removed from the mold to obtain the desired plastic skin material.

In the above, the mold 24 and the bucket 22 are closed,
A molding example has been described in which the thermoplastic plastic powder is moved and molded into the mold 24 by inverting the mold, but as shown in FIG. A floating device 25 may be provided, and after the mold 24 is placed on the bucket 22, the powder floating device 25 is driven to cause the powder to adhere to the mold surface 24a of the mold to form a molten film. It is. Note that 27 is a drive motor.

(Effects of the Invention) In the powder slush molding apparatus according to the present invention, the peripheral wall of the powder accommodating part of the bucket is aligned with the outer periphery of the product forming part of the mold, and the outer periphery of the product molding part of the mold is is sealed.

Therefore, during molding of the plastic skin material, there is no risk of the thermoplastic plastic powder adhering to parts other than the product molding part of the mold, and no flakes will be formed. As a result, pari removal work becomes unnecessary and loss of raw materials can be prevented. Furthermore, since pari in the semi-baked state does not adhere to the mold, there is no risk of degrading the physical properties of the product.

In addition, the sealing material used is a silicone rubber foam that can withstand the high temperatures during molding of the plastic skin material, and its hollow shape makes it easy to deform during crimping, so it always maintains a good seal. As a result, it becomes possible to effectively prevent Paris.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a powder slush molding apparatus according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of the upper part of the peripheral wall in FIG. 1, and FIGS. Figure J5 is a process diagram explaining the molding of a plastic skin material using the molding apparatus shown in Figure 1, Figure 6 is a sectional view of the bucket of the powder slush molding apparatus in this inventive embodiment, and Figure 7 9th to 9th
The figure is a process diagram illustrating the molding of a plastic skin material using a conventional molding device. 22° Bucket, 22a Powder storage section, 23
Peripheral wall, 24° oval mold, b Product molding part, 24b Product molding part outer peripheral surface, 26 Sealing material Patent applicant Inoue MCP Co., Ltd. Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 R

Claims (3)

[Claims] (1) In a powder slush molding device consisting of a bucket containing thermoplastic plastic powder and a heatable mold placed on the bucket, the peripheral wall of the powder storage portion of the bucket is connected to the product forming portion of the mold. It is made to approximately match the outer peripheral shape, and a sealing material is provided at the upper end of the peripheral wall.
A powder slush molding apparatus characterized by having a structure in which the sealing material is pressed onto the outer circumferential surface of a product forming part of a mold when the sealing material is attached to the mold. (2) The powder slush molding apparatus described in the patent scope item 1, in which the sealing material is a silicone rubber foam. (3) The powder slush molding apparatus according to claim 1 or 2, wherein the sealing material has a hollow shape.