JPS63172618A - Manufacture if filmy plastic molded product - Google Patents

Abstract

PURPOSE:To obtain a filmy plastic molded product free from unnecessary flashes, by a method wherein adhesion of a thermoplastic powdery material, melting of the adhered powdery material and formation of a film are performed by sticking a masking member to a cavity surface by abutting the masking member against the cavity surface so that the masking member covers a predetermined part of the cavity surface through a heat insulation material. CONSTITUTION:A mold 30 which has been heated is put over a basket 32, and the mold 30 and basket 32 are turned upside-down. A thermoplastic powdery material 48 in the basket 32 becomes a semi-molten state and stuck to the cavity surface 34 through heat of the cavity surface 34. Although the thermoplastic powdery material 48 comes into contact also with the outside of the masking member 38, heat transfer to the masking member 38 is prevented through heat insulation material 40. As the masking member 38 is at a temperature lower than the melting temperature of the powdery material, the contacting powdery material is neither heated nor stuck to the masking member 38. The mold 30 and basket 32 are turned upside-down and the surplus thermoplastic powdery material is accommodated into a housing part 44 of the basket. when the mold 30 is cooled, a molten film is cured and demolding is performed. a filmy plastic molded product in a desired form is obtained. A product free from flashes is obtained by providing the masking member 38.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a film-like plastic molded article by a powder slush molding method.

(Prior Art) Conventionally, film-like plastic molded products used as outer skins of vehicle armrests, furniture cushion products, etc. have been manufactured by various methods. Among these manufacturing methods, the powder slush molding method is a method that has been attracting attention in recent years because it can easily produce thin films or films with elaborate patterns, shapes, etc.

This powder slush molding method produces plastic film.
As shown in FIG. 3, the method for manufacturing a molded product involves manufacturing a film using a packet 12 containing a thermoplastic plastic powder 10 and a heatable mold 14 having a cavity surface 14a. The outline is as follows. First, heating means 1 such as a heating medium circulation pipe, etc.
The mold 14 heated in step 6 is placed over the packet 12 containing the thermoplastic plastic powder 10 with a lid, and the mold 14 and the bucket 12 are rotated and turned upside down. Thermoplastic powder lO is moved and lowered into the cavity. The thermoplastic plastic powder lO that has moved into the cavity comes into contact with the heated cavity surface 14a and adheres to the cavity surface 14a in a layered manner. Thereafter, the mold 14 and the bucket [2 are rotated again to return to their original positions, and the surplus thermoplastic powder that was not used for the deposition is accommodated in the packet 12. Then, if necessary, further heat the mold 14,
The adhered powder 10 is melted and gelled to form a molten film. Subsequently, the mold 14 is cooled, thereby hardening the molten film to fix its shape, and by removing the cured film from the mold, a desired film-like plastic molded product is obtained.

By the way, the packet 12 is usually larger than the product molding part of the mold 14 so that it can be used in various molds, and the mold cavity surface is also larger than the product molding part to match the packet. rub Therefore, in the past, when the thermoplastic powder is inverted, it adheres to the periphery of the product molding part on the cavity surface 14a, and unnecessary burr is formed on the outer periphery of the product. As this became necessary, there was a loss of raw materials.

Therefore, in order to solve these problems and manufacture film-like plastic molded products, the applicant filed a patent application in 1986-286.
No. 683 was filed for an invention related to a powder slush molding device. The powder slush molding equipment is the fourth
As shown in the figure, in the thermoplastic powder storage section 18 of the packet 17,
A plate-shaped peripheral wall 20 is provided to substantially match the outer peripheral shape of the product molding part a of the mold 22, and a sealing material 2 is provided at the upper end of the peripheral wall 20.
4 is provided, and when the mold 22 is placed over the packet 17, the sealing material 24 is pressed against the cavity surface to seal the core portion. By manufacturing a film-like plastic molded product using this molding equipment, it is possible to prevent thermoplastic plastic powder from adhering to the cavity surface other than the product molding part a, that is, to mask it, and the above-mentioned problem can be solved. It was.

(Problem to be Solved by the Invention) However, most of the cavity surface 23 of the mold 22 is a concave curved surface, and the plate-shaped peripheral wall 20 installed on the bucket 7) side may not contact the cavity surface perpendicularly. I have a problem.

Therefore, depending on the shape of the cavity surface (product shape), there is a risk that sealing defects may occur during the production of film-like plastic molded products. In addition, in order to bring the plate-shaped peripheral wall 20 into contact with the cavity surface perpendicularly, it is necessary to provide a plane substantially perpendicular to the peripheral wall 20 on the cavity surface, but if you want to change the position of the peripheral wall 20 (the masking part (if you want to change)
, or when changing the shape of the peripheral wall 20, the shape of the cavity surface must be changed, which poses a problem of requiring an enormous number of man-hours.

The present invention solves the above-mentioned problems of the prior art, namely, that depending on the shape of the cavity surface, it may not be possible to completely prevent the formation of a plastic film on unnecessary parts of the cavity surface, and The purpose is to solve the problem that it is not easy to mask parts, and furthermore, to provide a manufacturing method that can perform masking more efficiently.

(Means for Solving the Problems) The first invention provides a film-like plastic by a powder slush molding method in which thermoplastic plastic powder is adhered to the mold cavity surface and the adhered powder is melted to form a film. In a method for manufacturing a molded product, a masking member having a desired shape is fixedly attached to a cavity surface via a heat insulating material so as to cover a predetermined portion of the cavity surface, thereby controlling the adhesion of the thermoplastic plastic powder and the adhesion of the adhered powder. It is characterized by melting and forming a film.

A second invention is a method for manufacturing a film-like plastic molded product using a powder slab molding method, in which a masking member having a desired shape is placed so as to cover a predetermined portion of a cavity surface, and to leave a space between the masking member and the cavity surface. The thermoplastic plastic powder is adhered to the cavity surface through a heat insulating material, and while the air in the space is circulated with outside air or cold air, the thermoplastic plastic powder is attached to the cavity surface and the adhered powder is melted. and forming a film.

(Operation) First, the first invention will be explained. A first aspect of the invention is to apply a masking member having a desired shape to a predetermined portion of the cavity surface, and to contact and fix the masking member to the cavity surface via a heat insulating material, and to apply thermoplastic plastic powder to the cavity surface using a powder slush molding method. A film-like plastic molded article is produced by adhering a body, melting the adhered material, and cooling and hardening the melted material. That is, a film is formed by covering a predetermined portion of the cavity surface with a masking member. Therefore, it has the following effects.

The cavity surface is heated in advance to a predetermined temperature by a heating medium flowing through a circulation pipe provided in the mold in order to adhere and melt the thermoplastic plastic powder. However, in the part where the cavity surface is covered by the masking member, since the masking member is in contact with the cavity surface through the insulation material, the heat of the cavity surface is difficult to be transmitted to the masking member, and the temperature of the masking member surface is lower than that of the cavity surface. temperature (and is maintained lower than the melting temperature of the thermoplastic plastic powder. Furthermore, if a space is provided between the masking member and the cavity surface, the effect of heat radiation from the cavity surface can be reduced. Therefore, even if the thermoplastic plastic powder comes into contact with or adjoins the masking member by inverting the mold and the packet, the powder will not be heated because the temperature of the surface of the masking member is lower than the melting temperature of the powder. The material will not become semi-molten and will not adhere to the masking member.

That is, only the portion of the cavity surface covered by the masking member is free from adhesion of the thermoplastic plastic powder, and the powder is adhered to the other portions. As a result, even if a film is formed on the cavity surface by subsequent melting and gelling of the thermoplastic plastic powder and cooling and hardening of the melt, the film will not be formed on the portion covered by the masking member.

Therefore, by masking (covering) the portion of the cavity surface where the film is not desired to be formed with the masking member, the formation of the film on the core can be prevented.

In addition, since the masking member is brought into contact with the cavity surface via the heat insulating material and fixed to the mold by the fixing means, the heat insulating material is sandwiched between the masking member and the cavity surface, and the heat insulating material also acts as a sealing material. become. As a result, it is possible to reliably seal between the masking member and the cavity surface.

Furthermore, since the heat insulating material is located between the masking member and the cavity surface and acts as a seal as described above, even if the shape of the cavity surface at the mounting part of the masking member is not flat, the distance between the masking member and the cavity surface can be ensured. Can be sealed. Therefore, any part of the cavity surface can be masked without being affected by the cavity surface shape, and the masking position can be changed without changing the cavity surface shape (this can be easily done).

On the other hand, in the second invention, a space is provided between the masking member and the cavity surface, the masking member is fixed to the mold as in the first invention, and the air in the space is circulated with outside air or cold air. , adheres thermoplastic plastic powder to the dedicated surface, melts it, and forms a film.

Therefore, in this second invention, in addition to the effect of the first invention, the masking member is forcibly cooled, so that the masking member absorbs the thermoplastic plastic powder by heat dissipation from the cavity surface. It is possible to reliably prevent heating above the melting temperature, and it is possible to more reliably prevent the thermoplastic plastic powder from adhering to the masking member.

(Example) The present invention will be explained below based on embodiments and with reference to the drawings.

FIG. 1 is a sectional view of a mold 30 and a packet 32 used in carrying out the first invention.

The mold 30 is usually an electroforming mold, and has a cavity surface 3 on the inner surface.
4 is formed, and a heat medium circulation pipe 36 as a heating means is disposed on the outer surface. As a heating means,
There are various means other than circulating the heat medium, and depending on the means, a circulation pipe may not be necessary.

Further, the cavity surface 34 is made larger than the product molding part (the part that will become the product) for reasons such as matching the size of the packet 32. A masking member 38 is fixed to the mold 30 so as to cover a predetermined portion of the cavity surface 32, that is, a portion to which the thermoplastic powder is not desired to adhere.

The masking member 38 is made of Ia fiber reinforced plastic (F
RP) molded products or ceramic molded products, etc., which have high rigidity and a specified heat resistance,
The shape thereof may be a flat plate shape that is substantially the same as the predetermined portion of the cavity surface shape, a hollow box shape as in this example, or any other shape that can cover the predetermined portion of the cavity surface. Particularly when thermoplastic powder is deposited on the outer surface of the masking member.
In order to prevent the masking member 38 from slipping easily from the outer surface, the outer surface of the masking member 38 is configured to have no four parts and to form a slope in the depth direction of the cavity. It is preferable that the outer surface of the masking member 38 be as smooth as possible.

The heat insulating material 40 is made of an asbestos board, a rock wool board, etc., and is sandwiched between the masking member 38 and the cavity surface 34. Therefore, the heat insulating material 40 acts not only as a heat insulator but also as a sealing material. Further, as shown in FIG. 2 showing a cross section of a part of the mold example used in the second invention, a heat-resistant elastic body 40a such as silicone rubber or fluorine rubber is placed between the heat insulating material 40 and the masking member 38. It may be provided. In this way, even if the cavity surface 34 has large irregularities and the sealing action of the heat insulating material 40 cannot completely seal between the cavity surface 34 and the masking member 38, the heat-resistant elastic body 40a
Since it is sandwiched between the heat insulating material 40 and the masking member 38 and is compressively deformed, the above-mentioned sealing can be performed completely.

Therefore, a desired portion can be masked without being affected by the cavity surface shape.

Further, the means 11 for fixing the masking member 38 to the mold 30
As the second method, there are means such as screwing with bolts and nuts, or fixing a clip to the inner surface of the masking member 38 and locking the clip to the mold 30.

The masking member fixed to the mold by the fixing means and the cavity surface may be in contact with each other without any gap through the heat insulating material, but as shown in FIG. It is preferable to provide a space 39 and abut against each other. The reason for this is that by providing the space 39, the influence of heat radiation from the cavity surface 34 can be reduced.

The partial packet 32 has an internal housing section 44 for thermoplastic powder, and an external seven rung section 46 having a shape that matches the mold 30.

Next, an example of manufacturing a film-like plastic molded product according to the first invention will be explained according to the steps.

First, a thermoplastic plastic powder 48 such as vinyl chloride resin powder or polyethylene powder is put into the powder storage section 44 of the packet 32 .

Next, a heating medium such as thermal oil is passed through the circulation pipe 3 in advance.
The packet 32 is covered with a mold 30 which has been heated by passing it through the gold J! 230 and packet 3
Rotate 2 and turn it upside down.

As a result of this inversion, the thermoplastic plastic powder 48 contained in the packet 32 is contained in the mold 30 and comes into contact with the cavity surface 34, and is immediately turned into a semi-molten state by the heat of the cavity surface 34. It attaches to 34. At this time, the thermoplastic plastic powder 48 also comes into contact with the outer surface of the masking member 38, but the heat insulating material 40 prevents heat transfer from the cavity surface 34 to the masking portion 38, and the masking member 38 Since the temperature is lower than the temperature and lower than the melting temperature of the powder, the contact powder will not be heated to a semi-molten state and will not adhere to the masking member 38. In particular, when a space 39 is provided between the cavity surface 34 and the masking member 38, heating of the masking member 38 due to heat dissipation from the cavity surface 34 is suppressed, so that the temperature of the masking member 38 can be lowered. Therefore, adhesion of the powder can be more reliably prevented. The powder that has come into contact with the outer surface of the masking member 38 slides down from the outer surface of the masking member 38 due to the slope of the outer surface of the masking member 38 and the smoothness of the outer surface, and does not accumulate on the outer surface of the masking member 38. As a result, even if the temperature of the masking member 38 is close to the melt gelling temperature of the thermoplastic powder 48, the powder 48
Even if there is a risk that if it comes into contact with the masking member 38 for a long time, it will become semi-molten and adhere to the masking member 38,
Such adhesion does not occur.

Thereafter, the mold 30 and the packet 32 are rotated to return the packet 32 to its original position, ie, the packet 32 is placed down, and the excess thermoplastic powder not used for the deposition is stored in the container 44 of the packet.

In this way, the thermoplastic plastic powder adhering to the cavity surface 34 except for the portion covered by the masking member 38 is further heated, if necessary, in the mold 30 to melt and gel, thereby forming a molten film. do.

After that, the mold 30 is cooled to harden the molten film,
By removing the cured film from the mold, a film-like plastic molded product having a desired shape can be obtained.

The obtained molded product has no film formed on the portion covered by the masking material 38.

Therefore, by providing the masking member 38 in a part of the mold other than the product molding part, a product without flakes can be obtained.

Next, the production of the film-like plastic molded product according to the second invention will be explained.

FIG. 2 is a sectional view of a main part of a mold example 30a used in the second invention. This mold 30a has a space 39 between the masking member 38 having the desired shape and the cavity surface 34a.
and a heat insulating material 40 and the heat resistant elastic material 40
It is fixed to a predetermined part of the cavity surface by a fixing means 42 via a. A hole 49 is formed in a predetermined portion of the cavity surface 34a covered by the masking portion t438, and an air pressure hose 50 for blowing cold air or outside air into the space 39 is connected to the liquid hole 49.

A second invention is to manufacture a film-like plastic molded product by a powder slush molding method using this mold 30a and the packet 32, but the content thereof overlaps with the invention in accordance with the first invention. Since there are many parts, the second invention will be explained by simplifying the overlapping parts.

Thermoplastic plastic powder is first put into the packet 32, and the packet 32 is covered with a heated mold 30a. At this time, cold air or outside air is forced into the space 39 between the masking member 38 and the cavity surface 342 from the air press-in hose 50, and the air in the space 39 is circulated together with the cold air or outside air.

As a result, the masking member 38 is cooled to a lower temperature than that of the first invention, and is reliably maintained at a temperature lower than the melting temperature of the thermoplastic powder. Furthermore, if a small hole is provided in the mold 30a around the hole 49 for connecting the hose 50, the air in the space 39 can be circulated better.

Next, as in the first invention, the mold and the packet are rotated, turned upside down, and further rotated and returned to their original positions, thereby adhering the thermoplastic plastic powder to the cavity surface. At this time, the masking member 38 is cooled by circulating the air in the space 39 with outside air or cold air, and the temperature is lower than the cavity surface temperature and lower than the melting temperature of the powder, so that the masking member 38 is Member 38
Thermoplastic powder will not adhere to the material.

Therefore, on the cavity surface, only the portion covered by the masking member 38 is free from adhesion of thermoplastic plastic powder.

Thereafter, the adhering powder is melted and gelled to form a molten film as described above, and then the mold is cooled to form a hardened film on the cavity surface.If the film is removed from the mold, the desired film shape can be obtained. Obtain plastic molded products. The molded product has no film formed on the portion of the cavity surface covered by the masking member.

(Effects of the Invention) The first invention is such that when manufacturing a film-like plastic molded product by a powder slush molding method, a masking member having a desired shape is placed to cover a predetermined part of the cavity surface via a heat insulating material. By bonding and forming a film, we were able to obtain the following effects.

That is, it was possible to prevent the thermoplastic plastic powder from adhering to a predetermined portion of the cavity surface covered with the masking member and to the masking member, and to prevent the formation of a film on the core portion (masking). It is. Therefore, by providing a masking member to cover a predetermined portion of the cavity surface where a film is not desired to be formed, it has become possible to obtain a film-like plastic molded product without unnecessary flakes.

Furthermore, it has become possible to reliably mask any part of the cavity surface without being affected by the shape of the cavity surface.

On the other hand, the second invention provides that when manufacturing a film-like plastic molded product by a powder slush molding method, a masking member having a desired shape is placed on the cavity surface via a heat insulating material so as to form a space between the masking member and the cavity surface. sticks in contact with the
Since the film was formed while circulating the air in the space with outside air or cold air, the following effects could be obtained.

In other words, the masking member can be kept at a lower temperature more reliably,
It is now possible to completely prevent thermoplastic powder from adhering to the masking member, making it possible to perform masking more reliably.

Moreover, the effect of the first invention, which is that any part can be reliably masked without being affected by the cavity surface shape, can be achieved without impairing it.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a mold and a packet used in the first invention, and FIG. 2 is a sectional view of a part of the mold used in the second invention. Further, FIG. 3 is a sectional view of an example of a mold and a packet used in the conventional manufacturing method, and FIG. 4 is a sectional view of a conventional powder slush molding apparatus. 30.30a Mold, 38 Masking member, 39
Space, 40 Insulation material, 40a Heat-resistant elastic material Patent applicant Inoue MCP Co., Ltd. No. 1 Figure 112

Claims (3)

[Claims] (1) A masking member having a desired shape in a method of manufacturing a film-like plastic molded product by a powder slush molding method in which thermoplastic plastic powder is adhered to a mold cavity surface and the adhered powder is melted to form a film. is brought into contact with and fixed to a predetermined part of the cavity surface via a heat insulating material, and the thermoplastic plastic powder is attached, the adhering powder is melted, and a film is formed without forming a film on the masking part. A method for producing a film-like plastic molded product, characterized by: (2) A method for manufacturing a film-like plastic molded product according to claim 1, wherein a space is provided between the cavity surface and the masking member. (3) A masking member having a desired shape in a method of manufacturing a film-like plastic molded product by a powder slush molding method in which thermoplastic plastic powder is adhered to a mold cavity surface and the adhered powder is melted to form a film. is fixed in contact with the cavity surface via a heat insulating material so as to cover a predetermined part of the cavity surface and to form a space between the cavity surface and the air in the space to outside air or cool air. A method for producing a film-like plastic molded product, which comprises adhering thermoplastic plastic powder, melting the adhering powder, and forming a film while circulating the product.