JP3289079B2 - Method for producing foamed molded article having improved surface appearance - Google Patents

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 foamed molded article having an improved surface appearance, such as expanded polystyrene, expanded polyethylene, and expanded polypropylene. The present invention relates to a method for producing the foamed molded article, which improves the appearance of the surface.

[0002]

2. Description of the Related Art Expanded synthetic resins represented by expanded polystyrene are widely used for various packaging containers and transport containers because of their excellent buffering properties and heat insulating properties. In molding, thermoplastic foaming resin particles such as polystyrene (foamed beads) are used as raw materials, filled into male and female molds, heated, melted and cooled, and molded into products by the so-called bead method. In-mold foam molding is performed in accordance with each form.

However, since the in-mold foam molded product obtained by the above-described bead method is press-molded using pre-expanded beads as a raw material, the resulting molded product has a turtle-shaped pattern or a vapor formed by fusion of expanded beads. A pattern of holes was formed, which governed the appearance of the molded product, and showed that foam molding was carried out by the bead method, which was an obstacle to expanding the application.

Therefore, the present inventors focused on improving the surface appearance of the foamed molded product by the above-described bead method, and previously heated and pressed the surface of the foamed molded product, thereby destructing the surface by the destruction of the surface cell structure. By clearing the film, the external appearance image of the conventional bead method foam molded product is wiped out and packaging is performed.
It was proposed to expand the range of applications and applications not only in the buffer field. (Japanese Patent Application No. 3-110958)

[0005] After that, various studies have been continued on the improvement of the appearance of the foamed molded product, and by changing the degree of pressing at the time of heating and pressing without changing the surface of the foamed molded product. It has been found that surface attachment with various inserts or mesh fabrics is possible.

[0006]

However, in each of the above methods, regardless of whether the surface is formed into a film or a net-like cloth is applied to the surface and the cloth is integrated through the mesh,
In any case, the surface of the foamed molded body is pressed by using the heating mold to break the cell structure on the surface. When the mold is to be released from the foamed molding, the molten surface of the foamed molding adheres to the heating mold and peels off together as it is. To release the heating mold, it is necessary to wait until the mold cools before releasing the mold. In other words, the molding cycle was prolonged and the productivity could not be reduced.

[0007] Cooling a heated mold that has been heated at an angle requires time to heat again and results in loss of energy. In addition, heating and cooling the mold requires damage to the mold. There is also a difficulty that is likely to occur. However, the use of two or more heating dies increases the equipment cost and is economically problematic.

[0008] The present invention addresses the above-mentioned situation and uses a heating mold by interposing a heat-resistant sheet that does not fuse at a temperature higher than the melting point of the foamed molded product and does not permeate the molten resin on the surface of the foamed molded product. It is an object of the present invention to simplify the peeling after press shaping, to improve the appearance of the foam molded article after shaping, to reduce the cost, to accelerate the molding cycle, and to improve the productivity.

[0009]

In order to achieve the above-mentioned object, the method of the present invention comprises the steps of:
First, it does not heat fuse at a temperature higher than the melting point of the foam molded article,
Moreover, the outer surface of the foamed molded article was covered with a heat-resistant sheet material that does not transmit the molten resin due to the surface melting. Then, the surface of the foamed molded product is pressed by a heating mold through the heat-resistant sheet-like material, and the surface cell structure is destroyed and melted.
The pressurized hot mold is removed, and pressed in place of the cold却型immediately,
After cooling to not Teso was allowed remove heat sheet coated outer surface.

In addition to diversifying the surface appearance of the foam molded article obtained as described above, prior to the application of the heat-resistant sheet-like material, a sheet through which a molten resin such as a wire mesh or coarse cloth permeates the outer surface of the foam molded article. It is also effective to arrange the shapes and then apply the above method. (Claim 2)

In particular, the heat-resistant sheet used in the above-mentioned method is one which does not fuse even when the surface of the foamed molded product is melted at a temperature higher than the melting point of the foamed molded product. It is important that the material does not permeate to the outside, and examples thereof include a metal sheet or film, a high-melting point plastic sheet or film, and a cloth having a dense structure, and at least one of them is used.

[0012]

According to the method of the present invention, the outer surface of the foamed molded article is shaped into a predetermined form or pattern by pressing the heating mold, and even if the surface is melted, the heat-resistant sheet-like material is not integrated at all. It can be easily released as it is because it is simply covered, and when using a metal or plastic sheet or film, a beautiful and glossy surface can be obtained. In this case, the appearance can be improved, such as obtaining a dull appearance. In particular, when the heat-resistant sheet is a fabric, it is possible to form an appearance in which a fabric pattern is transferred.

[0013]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 (a) to 1 (d) show a production process according to the present invention. In the drawings, reference numeral 1 denotes a foamed molded article foamed in a mold by a bead method, and 2 denotes a heat-resistant sheet adhered to the outer surface thereof. Things.

Here, the above-mentioned foamed molded article may be a general foamed molded article, but is usually a foamed molded article of polyethylene, polypropylene, polystyrene or the like, and is usually an in-mold foamed molded article by a bead method. . Accordingly, in-mold foam moldings such as (meth) acrylate-styrene copolymers, acrylonitrile-styrene copolymers, and copolymers of polystyrene and polyethylene, which can be subjected to in-mold foam molding, can of course be applied. The foamed article is not limited to a cubic or rectangular parallelepiped, but may be of various shapes or a basic form of various products.

On the other hand, the heat-resistant sheet-shaped material must not be heat-sealed at a temperature higher than the melting point of the foamed molded article, and must have a property that the molten resin does not permeate and flow out even if the surface of the foamed molded article is melted. For example, a sheet of metal such as copper, aluminum, brass, stainless steel, or the like, a sheet of plastic such as film, nylon, polyester, or acrylic, or a dense fabric using a film or a fiber of nylon, polyester, or the like is used.

Of course, depending on the melting point of the foamed molding, there is still another thing, for example, in the case of polystyrene, the melting point is about 105 ° C.
The melting point is about 120 to 1 in the case of polyethylene.
30 ° C. and 110-150 for polypropylene
Since it is about ° C., any material that does not thermally fuse at a temperature higher than this can be relatively used.

The form of the heat-resistant sheet is generally a sheet such as a cloth or a metal plate, but depending on the product, a deformed sheet may be used as long as the intended purpose is met. it can.

In practicing the present invention, first, as shown in FIG. 1 (a), a heat-resistant sheet 2 is applied to the outer surface of the foamed molded body 1, and the outer surface is covered.

Then, in this state, the foam molded article 1 covered with the heat-resistant sheet-like material 2 is put into a mold 4 as shown in FIG. Pressing is performed by the heated heating mold 3, and the outer surface of the foamed molded product 1 is heated and pressed via the heat-resistant sheet-like material 2 adhered to the outer surface of the foamed molded product 1.

In the drawing, the heat-resistant sheet-like material 2 is only the upper surface of the foamed molded product 1, but the present invention is not limited to this, and the same applies to a part or an entire outer surface.

Thus, when the heating mold 3 is pressed and held for a required time, for example, 20 to 30 seconds as described above, the cells on the surface of the foam molding 1 are broken and melted. At this time, since the heat-resistant sheet-like material 2 does not transmit the molten resin, the surface-melted portion of the foamed molded article 1 does not transmit through the heat-resistant sheet-like material 2, and the inner surface of the heat-resistant sheet-like material 2 Thus, for example, in the case of a smooth metal flat plate, a surface corresponding to the smooth flat plate is formed, and in the case of a cloth, a fine uneven surface corresponding to the cloth is formed.

As described above, when the surface of the foamed molded body 1 is pressed by the heating mold 3 for a required time to form a surface corresponding to the heat-resistant sheet-like material 2, as shown in FIG. Then, the heating mold 3 is removed, and the mold is immediately replaced with the cooling mold 5 and pressed again. At this time, without using the cooling mold 5,
Although conceivable Rukoto is held to room temperature, however, it is preferable to use a cooled 5 from the surface to reduce the time to cool.

The heating mold 3 can be easily removed because the heat-resistant sheet 2 is interposed. By replacing the cooling mold 5, the original foamed molded article 1 can be obtained as a predetermined foamed molded article form 1 'with the heat-resistant sheet-like material 2 adhered. When the object 2 is removed from the surface (see FIG. 1D), the required product is finally completed. At this time, depending on the type of the heat-resistant sheet material 2, a glossy surface is obtained in the case of a smooth surface such as a metal sheet, and a glossy surface is formed in the case of a fine uneven surface such as a cloth. When a metal sheet and a fabric are used simultaneously, a partially different surface is obtained.

FIG. 2 shows a case where the above-mentioned method of the present invention is further modified. Before the outer surface coating with the heat-resistant sheet-like material 2, the molten resin by the surface melting of the foamed molded product 1 can pass through the foamed molded product 1. Covered with a transparent sheet material 6,
After that, it is covered with the heat-resistant sheet material 2.

In this case, the molten resin permeates through the permeable sheet material 6 and flows out to the surface side due to the melting of the surface of the foam molded article 1, forming a resin layer between the resin and the heat-resistant sheet material 2. The surface state of the heat-resistant sheet material 2 is transferred to the resin layer, and at the same time, the permeable sheet material 6 is embedded on the inner surface via the resin layer. Therefore, in the product form 1 ', the appearance of the transparent sheet material 6 can be improved by seeing through. As the permeable sheet-like material 6, a wire mesh, a net-like or coarse cloth is suitable.

A product having an improved appearance of a foamed article in this way is different from a conventional foamed article, and has an appearance different from that of a foamed article. In addition, since the substance is a foamed article, it is lightweight. It is used not only in the logistics packaging field, but also in various fields such as the sports and leisure field, the industrial components field, the housing equipment field, and the office supplies field.

[0027]

According to the present invention, as described above, in order to improve the appearance of the foamed molded article, the outer surface of the foamed molded article is not heat-sealed at a temperature higher than the melting point of the foamed molded article in advance, and the molten resin of the foamed molded article is reduced. After coating with a heat-resistant sheet material that does not permeate out, press the heated mold, melt the surface of the foamed molded body, remove the heating mold, immediately press at room temperature or with a cooling mold, and cool the surface It is a method of removing the heat-resistant sheet-like material that has covered the outer surface after that, the use of the heat-resistant sheet-like material cuts off the heating mold and the melted portion of the foam molded body surface, and facilitates removal of the heating mold. Depending on the type of heat-resistant sheet-like material, it is possible to form a glossy surface, a non-glossy surface, an uneven surface, and various pattern surfaces, etc., and it is possible to improve the appearance of the in-mold foam molded article beautifully Has a great effect

Moreover, the method of the present invention does not allow the heating mold to be integrated with the surface of the foamed molding because the surface of the heating mold and the foamed molding are cut off by the heat-resistant sheet as described above. It is easy to shape and can be replaced immediately at room temperature or cooling with a cooling mold, and it is possible to mold without waiting for cooling of the heating mold, shortening the molding cycle and greatly improving productivity. it can.

Further, since there is no need to cool the heating mold, there is little energy loss. Further, damage to the mold due to repeated heating and cooling is not only avoided, but equipment using a plurality of heating molds is used. It is a useful method in terms of low cost and extremely high efficiency by eliminating cost increase.

The invention described in claim 2 is effective in developing the above-mentioned invention, and in obtaining a foam molded article having a variety of appearances.

[Brief description of the drawings]

FIG. 1 is a process explanatory view showing one example of the method of the present invention;
(D) show the steps in order.

FIG. 2 is an explanatory view showing another embodiment of the method of the present invention.

[Explanation of symbols]

 Reference Signs List 1 foam molded product 1 'foam molded product product after molding 2 heat-resistant sheet material 3 heating mold 5 cooling mold 6 permeable sheet material

Claims (3)

(57) [Claims] 1. An outer surface of a foamed molded article is covered with a heat-resistant sheet which does not thermally fuse at a temperature higher than the melting point of the foamed molded article and which does not allow a molten resin to pass therethrough. After melting the body surface through a heat-resistant sheet,
Mold was removed, instead of the cold却型pressed again immediately, After cooling, the foamed molded article having an improved surface appearance and removing the heat-resistant sheet-like material obtained by covering the outer surface Manufacturing method. 2. A deposited an outer surface in molten resin permeable sheet material foam moldings, not heat-sealed over an outer surface at a temperature above the melting point of the foamed molded, yet resistant sheet-like impermeable to molten resin Covered with an object, pressed the heated mold to melt the surface of the foam molded article through the heat-resistant sheet material, and caused the molten resin to flow between the heat-resistant sheet material and the transparent sheet. after the mold was removed, instead of the cold却型pressed again immediately, after cooling, the foam having an improved surface appearance and removing the heat-resistant sheet-like material obtained by covering the outer surface A method for producing a molded article. 3. The heat-resistant sheet-like material is at least one selected from a metal sheet or film, a plastic sheet or film, and a densely-textured fabric.
A method for producing a foamed molded article having the improved surface appearance as described above.