JPH0560770B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a film-like molded product having a foamed resin layer, which is used as a skin material for automobile interior materials, furniture, and other products.

(Prior Art) Conventionally, the following powder slush molding method has been used as a method for producing a film-like molded product having a foamed resin layer.

First, as shown in FIG. 4, a powdered resin 14 containing a foaming agent is charged into a slush mold 12 having an opening 10. Then, by heat transfer from the preheated mold surface 13 of the slush mold, the powdered resins in the mold are welded together and adhered to the mold surface to a predetermined thickness. After that, slush mold 12
The excess powder resin that did not adhere to the mold surface is discharged from the slush mold 12 by inverting the mold. Next, the powdered resin layer on the mold surface is further heated to melt the powdered resin and decompose the foaming agent to cause foaming, thereby obtaining a film-like molded product having a foamed resin layer.

At that time, the heating of the powder resin layer attached to the mold surface is
This is accomplished by housing the slush mold in a heating oven, by passing a heat medium through a circulating pipe connected to the slush mold, or by immersing the slush mold in a fluidized bed of heat medium.

On the other hand, in order to produce a film-like molded product made by laminating a non-foamed resin layer and a foamed resin layer,
As described in Japanese Patent No. 101014, powdered resin containing no foaming agent is first put into a slush mold, adhered to the mold surface, and heated and melted to form a non-foamed resin layer. Thereafter, in the same manner as described above, a powdered resin containing a foaming agent is put into a slush mold and melted and foamed by heating to form a foamed resin layer on the non-foamed resin layer.

In addition, in the film-like molded product having the foamed resin layer obtained as described above, the part below the A-A section of the slush mold 12 is the product part. However, in order to obtain a homogeneous film-like molded product and to facilitate the injection process of polyurethane foam raw materials, etc. in the subsequent process, the slush mold 12 is provided with an extension surface 16 that expands following the opening edge. 13 and the extension surface 16, and
A large film-like molded product is formed by successively heating and melting the material. In addition, the parts that will become the mounting holes for meters, etc. on the instrument panel, or the mounting holes for the assist grips on the pillar garnish, such as part B, are originally unnecessary parts, but for the same reason as above, that is, the homogeneous film. In order to obtain a molded product, etc., it is continuously molded from other parts and then cut out.

The film-like molded product having the foamed resin layer thus obtained is then placed in a foam mold as a skin, and a liquid foaming raw material such as a polyurethane foam raw material is injected into the inner surface of the film-like molded product to form a pillar. Foam molded products such as garnishes are integrally molded.
At this time, the film extension formed by the extension surface 16 of the slush mold is sandwiched between the lower mold and the upper mold of the foam mold, and is used to hold the film-like molded product. In addition, in order to facilitate subsequent removal and to prevent wasteful use of the liquid foam raw material, the film in part B is sandwiched between the upper and lower molds of the foam molding mold. Foam formation is prevented.

After the foam molding, the film extension part and the film in part B of the film-like molded product are cut off from A-A along with the protrusion (burr) of the foam, and the mold surface below A-A of the slush mold is removed. The molded film-like product becomes the skin.

(Problems to be Solved by the Invention) By the way, the film-like molded product having a foamed resin layer molded in this way may be partially modified depending on the use, etc., to the degree of foaming of the foamed resin layer, that is, the degree of foaming of the powdered resin layer. Sometimes it's better to lower it. For example, like the film extension part or the film in part B,
In the area that is sandwiched between the foam molds during integral molding, it is preferable to reduce the degree of foaming of the foam resin layer in order to maintain a stable seal between the foam mold and the film-like molded product. Further, the film extension portion etc. are to be removed afterwards, and in order to facilitate the removal operation, it is preferable to reduce the degree of foaming of the foamed resin layer in this portion.

Therefore, it is desirable that the slush mold for obtaining such products be capable of partial heating or cooling. Therefore, some slush molds are used that have a heating medium circulation pipe arranged on the back side of the slush mold. Of the heating medium circulation pipes for powder resin adhesion and foaming provided in the slush mold, the heating medium is not passed through the portion where foaming is to be suppressed during heating and foaming of the powder resin, thereby increasing the heating temperature of the portion. An attempt has been made to suppress the foaming of the powdered resin in that part by making it lower than in other parts.

However, since slush molds are usually made of materials with excellent heat conductivity such as metals, even if the heat transfer medium (heating oil, etc.) stops heating only one part of the mold, the heat from other parts of the mold will still be absorbed. The temperature of the part increases with time. Further, due to the heat dissipation from the heat medium circulation pipe located near the portion, the portion is heated to a considerable extent.

For these reasons, in the past, even if attempts were made to suppress the foaming of the powdered resin layer adhering to the inside of the slush mold only in a predetermined portion, it was not possible to sufficiently suppress the foaming.

This invention was made in view of the above points,
When manufacturing a film-like molded product with a foamed resin layer,
It is an object of the present invention to provide a manufacturing method that can sufficiently suppress foaming of a powder resin layer in a predetermined portion.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a slush molding mold having an opening, in which a powdered resin containing a foaming agent is charged, and the powdered resin layer adhered to the inside of the mold. In a method of manufacturing a film-like molded product having a foamed resin layer by melting the powdered resin and decomposing the foaming agent by heating the powdered resin, the powdered resin layer is heated at the same time as heating from the mold surface. This is done by irradiating the layer surface with far infrared rays, and in a predetermined part of the powder resin layer surface, the surface is covered to block the far infrared rays, and the powder resin layer is molded while suppressing foaming in the part. That's what I did.

(Function) Far-infrared rays have the property of heating objects irradiated with far-infrared rays. Therefore, the powder resin layer containing the foaming agent adhering to the inside of the slush mold is heated from the mold surface and heated by far infrared ray irradiation, melting, and the foaming agent thermally decomposes and foams, forming the foamed resin layer. become. At that time, a predetermined part of the powder resin layer containing the foaming agent is shielded from far infrared rays by the cover, so it is not heated by the far infrared rays, preventing thermal decomposition of the foaming agent and suppressing foaming. be done. As a result, in the resulting film-like molded product having a foamed resin layer, the degree of foaming of the foamed resin layer is low in the portion where far infrared rays are shielded by the cover.

(Example) Hereinafter, the present invention will be explained by taking as an example a film-like molded product formed by laminating a non-foamed resin layer and a foamed resin layer.

First, the powdered resin forming the non-foamed resin layer and the powdered resin forming the foamed resin layer will be explained.

The powdered resin (hereinafter referred to as the first powdered resin) that forms the non-foamed resin layer is usually made by powdering a thermoplastic resin such as vinyl chloride resin and adding auxiliary agents such as stabilizers, plasticizers, and flame retardants. The added one is used.
Further, as the powdered resin (hereinafter referred to as the second powdered resin) forming the foamed resin layer, the first powdered resin composition containing a foaming agent is used. The blowing agent is one that is decomposed by heat, and includes, for example, an azo compound such as azodicarbonamide, a sulfonyl hydrazide compound such as benzenesulfonyl hydrazide, or other organic or inorganic blowing agent.

FIG. 1 is a sectional view of a slush mold 18 used in one embodiment of the present invention. This slush mold 18 is a mold for molding a film-like molded product used as the skin of a pillar garnish, and a pipe 20 for circulating a heat medium for heating the mold surface is installed on the outside of the mold. ing. A horizontal mold surface portion 18a protruding into the mold is a mold surface for molding a film portion in which a hole for attaching an assist grip is formed. Further, the inclined mold surface extension part 18b following the opening edge is formed into a mold for forming the film extension part which is sandwiched between the lower mold and the upper mold when the film-like molded product is held in the foam mold as described above. Both of the coating parts molded by the mold surface predetermined portions 18a and 18b are then cut away. Therefore, in the slush mold 18, the mold surface portion above C-C constitutes the original product molding section.

First, the opening 21 of the slush mold 18
is closed with a bucket 24 containing the first powdered resin 22, and the slush mold 18 and bucket 24 are rotated while the mold surface is preheated to 140 to 250°C with heated oil passing through the circulation pipe 20 on the outside of the mold. Then, the first powdered resin 22 is adhered to the mold surface of the slush mold 18. At this time, if there is an undercut part on the mold surface, the surplus of the first powder resin 22 will accumulate in the undercut part and will be difficult to discharge, so air is blown onto the part to remove the surplus powder resin. The slush mold 18 can be removed by blowing it out or using an air knocker (not shown) or the like every time the slush mold 18 reaches the upper position.
Vibration is applied to the slush mold 18 to remove excess powder resin 22 accumulated in the undercut portion of the mold surface from the slush mold 18, and to uniformly adhere the powder resin 22 to the mold surface. Removal of excess powdered resin using the air knocker is more efficient than removal by air blowing, and is also superior in terms of equipment.

After continuing to rotate until a predetermined amount of the first powder resin adheres to the mold surface, the excess powder resin 22 is returned to the bucket 24 with the opening 21 of the slush mold facing down, and the bucket 24 is then slush molded. It is removed from the mold 18 and the first powdered resin adhering to the mold surface is melted to form a non-foamed resin layer on the mold surface.

Note that the above steps are not necessary when manufacturing a film-like molded product consisting only of a foamed resin layer.

Next, the opening 21 of the slush mold 18 is closed with a bucket (not shown) containing a second powdered resin containing a foaming agent. Subsequently, the same rotation, vibration, etc. as described above are applied, and the heat retained in the non-foamed resin layer causes a predetermined amount of the second powder resin to adhere to the surface of the non-foamed resin layer. After the second powdered resin that has not adhered is stored in the bucket, the bucket is removed from the slush mold.
During this time, the temperature of the slush mold is preferably maintained below the thermal decomposition temperature of the blowing agent.

Thereafter, a far-infrared heater 26 is placed above the opening 21 of the slush mold as shown in FIG. Along with irradiating
The second powder resin layer 28 is heated by passing heated oil through the circulation pipe 20 on the outside of the mold. At that time, the second powder resin layer 28 attached to the part 18a of the mold surface
A cover 32 made of a metal plate or the like is provided over the area a to prevent far infrared rays from hitting the surface of the second powder resin layer 28a in this area.

By this far-infrared heating and heating from the mold surface by heated oil, the second powdered resin is melted and the foaming agent is thermally decomposed and foamed, thereby forming a foamed resin layer on the non-foamed resin layer 27. However, since the second powder resin layer 28a portion where the far infrared rays are shielded by the cover 32 is not heated by the far infrared rays, thermal decomposition of the foaming agent is suppressed, resulting in a foamed resin layer with a low degree of foaming. In addition, since the surface of the second powder resin layer 28b attached to the mold surface extension 18b is inclined with respect to the irradiation direction of the far infrared rays 30, the amount of far infrared rays irradiated per unit area is higher than that of the other horizontal It is smaller compared to the mold surface part. Therefore, the portion of the second powder resin layer 28b attached to this portion is not heated much by the far infrared rays, and foaming is suppressed, resulting in a foamed resin layer with a low degree of foaming. At this time, it is preferable to partially reduce the heating from the mold surface in the foamed resin layers 28a and 28b that suppress foaming. Of course, the mold surface extension part 1
8b as well, a cover may be provided on the second powder resin layer 28b to shield far infrared rays.

The heating with far infrared rays is performed so that the temperature of the second powder resin layer irradiated with far infrared rays is about 160 to 250°C, but heating by far infrared rays alone will not be sufficient. As mentioned above, heated oil at a predetermined temperature is passed through the circulation pipe 20 to supplement heating. At this time, it is better to prevent heated oil from passing through the mold surface extensions locally in order to lower the mold surface temperature.

The film-like molded product having the foamed resin layer thus molded is removed from the slush mold after being cooled. FIG. 3 is a sectional view of a film-like molded product 34 having a foamed resin layer obtained in this manner. The film-like molded product 34 has a non-foamed resin layer 27.
A foamed resin layer 36 is laminated on the back side of the
Portion 3 where far infrared rays are shielded by the cover 32
4a, and the foamed resin layer 36 at the coating extension part 34b that was inclined with respect to the far-infrared irradiation direction.
The foaming has been suppressed.

The film-like molded product 34 having the foamed resin layer is
During subsequent molding of the beer garnish, it is placed in the foam mold as a skin. At this time, the portions 34a and 34b where the foaming has been suppressed are sandwiched between the lower mold and the upper mold of the foaming mold, and the film-like molded product 34 is held in the foaming mold. And film-like molded product 3
4. A polyurethane foam raw material or the like is injected into the inner surface, and the foam is integrally molded on the inner surface of the film-like molded product. Thereafter, the film-like molded product 34 is cut from CC, and the portion below CC becomes the skin. Also, by cutting, an assist grip attachment hole is formed at the portion 34a.

(Effects) This invention covers the surface of a predetermined portion of the powder resin layer when heating the powder resin layer containing a foaming agent adhering to the inside of the slush mold by irradiating far infrared rays at the same time as heating from the mold surface. Since it shields far infrared rays, it is possible to suppress heating in this area and sufficiently suppress foaming of the powdered resin.

Moreover, by partially shielding far infrared rays and making the mold surface temperature of the foaming suppressing part lower than other parts,
A better foaming suppression effect can be obtained.

As a result, it is possible to obtain a film-like molded product that suppresses foaming in the predetermined areas that will be sandwiched between the lower mold and the upper mold of the foam mold during integral molding of the skin, and the foam mold and the film-like molded product Good sealing can be achieved with the Furthermore, it is possible to obtain a film-like molded product in which foaming is suppressed in a predetermined portion that is to be removed, and the removal can be easily performed.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views illustrating practical examples of this invention, Figure 3 is a cross-sectional view of a film-like molded product having a foamed resin layer obtained by implementing this invention, and Figure 4 is a powder It is a sectional view explaining a slush forming method. 18: Slush mold, 30: Far infrared rays, 3
2: Cover.

Claims (1)

[Claims] 1 Powdered resin containing a foaming agent is placed in a slush molding mold having an opening, and the powdered resin layer adhering to the mold is heated to melt the powdered resin and decompose the foaming agent. In a method for manufacturing a film-like molded product having a foamed resin layer, the powder resin layer is heated by heating the powder resin layer from the mold surface and simultaneously irradiating the surface of the powder resin layer with far infrared rays. A method for manufacturing a film-like molded article having a foamed resin layer, characterized in that in the part, the surface is covered to shield far infrared rays, and the molding is carried out while suppressing foaming of the powdered resin in the part.