JPH07156182A - Foamed resin molded article with skin and production thereof - Google Patents

Abstract

PURPOSE:To obtain a foamed resin molded article with a skin and a production method thereof in which a shortage, a failure in fusing, and the like do not occur in a foamed body even if a non-permeable skin is used. CONSTITUTION:In a production method of a foamed resin molded article 7 with a skin by providing the outer surface of a foamed body 71 with a skin 12, the skin 12 is set in a foaming mold, the mold is closed, and foamable resin particles are charged into a cavity 15 by air and simultaneously, the accompanying air is discharged outside the cavity 15 through return pipes 5 projected in the cavity 15. After that, steam is supplied into the cavity 15 to accelerate the expansion and fusion of the resin particles 3 while the steam and its condensate are discharged outside the cavity 15 through the return pipes 15. In this manner, the foamed body 71 is formed integrally with the skin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foamed resin molded article with a skin in which the outer surface of a foam is covered with a skin and a method for producing the same.

[0002]

2. Description of the Related Art Foamed resin particles, such as polypropylene, are expanded by heating, and the surface of the foamed resin particles is fused to form a foamed material that is lightweight and highly heat-retaining. Suitable for heat insulating materials. However, with the foam as it is, the porous surface is exposed and the heat retention efficiency is poor,
In addition, since there is a concern about mold and other troublesome problems in the above-mentioned bathing areas such as baths, there has been a strong demand for an integral skin product having a non-breathable skin on the foam surface.

[0003]

However, when the non-breathable skin is set in the foaming mold and an attempt is made to manufacture a skin-integrated foamed product, the following problems occur. The air (the air flow is indicated by an arrow) sent together with the resin particles 3 from the raw material filling machine into the cavity 15 cannot pass through the cavity mold 12 by the skin 72, and enters the communication hole 111 of the core mold 11. (Fig. 7). The resin particles 3 are also entrained in the air and swirl in the cavity to form the communication hole 1
11 (the communication hole diameter is smaller than the resin particle diameter). For this reason, as shown in FIG. 8, an unfilled portion 91 is formed in the cavity 15 near the cavity mold 12, causing defective fusion.

Further, steam heating is performed to fuse the resin particles 3 filled in the cavity 15 with each other.
The discharge port for the steam injected into the cavity 15 from 11 was only the communication hole 111 because of the skin 72. Therefore, as shown in FIG. 9, the vapor could not circulate all over the cavity, and the dead zone 92 was created. As a result, the fusion between the skin 72 and the resin particles 3 and the fusion between the resin particles in the vicinity of the skin 72 were not completed sufficiently. In particular, when steam that escaped near the epidermis cooled and became condensed water, its surroundings remained almost unmelted. As a result, defects such as peeling, swelling, wrinkles, and insufficient strength of the skin 72 were caused.

On the other hand, various manufacturing methods for integrally molding a skin on a foam of resin particles have been disclosed in the past (Japanese Patent Laid-Open No. 61-61).
No. 127333, etc.). However, in the technique of forming an air vent hole in the plastic sheet 73 and integrally molding it (Japanese Patent Application Laid-Open No. 61-127333), as shown in FIG. 10, when the resin particles 3 are filled, air flows from the core mold 11 to the cavity mold 12 Although it can be manufactured well by flowing into, the problems such as mold formation have not been solved yet due to the presence of air vent holes provided in the product. Further, in the invention in which a breathable sheet is attached to the back of the skin and vapor is allowed to pass through from there (JP-A-61-211019), the manufacturing process is too complicated. Furthermore, in the invention in which a steam injection pipe is provided in the cavity (Japanese Patent Laid-Open No. 1-283130), steam condensed water remains between resin particles, fusion cannot be completely achieved, and the skin is set on the upper mold. Technology (JP-A-61)
-239934), it is difficult to set the epidermis,
Moreover, only a vertical molding machine can be applied, and in addition, the foam is allowed to be limited to a thin material.

The present invention solves the above-mentioned problems, and there is no restriction on the shape of the foam, the molding machine, etc., and even if a non-breathable skin is used, the inside of the foam will not be lost or defective in fusion. An object of the present invention is to provide a foamed resin molded article with a skin and a method for producing the same.

[0007]

Means for Solving the Problems A foamed resin molded article with a skin of the first invention is a foamed body formed by fusing expandable resin particles with steam as a heating medium, and the fusion of the resin particles. And a skin attached to the outer surface of the foam, and an insertion hole for a vapor return pipe for heating the resin particles toward the inside of the foam is formed on the back surface side of the foam. It is characterized by The method for producing a foamed resin molded article with a skin according to the second aspect of the present invention is the method for producing a foamed resin molded article with a skin in which the outer surface of a foam is covered with the skin, and the method comprises: Mold and then inject the foamable resin particles into the cavity by air transfer, and use the return pipe projecting inside the cavity to discharge the entrained air to the outside of the cavity, and then supply steam to the cavity to supply the resin. It is characterized in that a foam integrated with the skin is formed so that steam and its condensed water are discharged from the return pipe while accelerating the heat fusion of the particles. Here, the operations of "supplying steam into the cavity" and "discharging steam and its condensed water out of the cavity" include not only simultaneous operation but also sequential operation. Further, "supply of steam into the cavity" and "discharge of steam and its condensed water to the outside of the cavity" may be continuous operation or intermittent operation.

[0008]

According to the foamed resin molded article with the skin and the method for producing the same according to the present invention, even if a non-air-permeable skin is used as the skin, the air that has been sent into the cavity together with the resin particles by air conveyance is Then, the resin particles are discharged to the outside of the cavity through the return pipe arranged so as to project, and the entire area of the cavity is smoothly and evenly filled with the resin particles. Further, even in the case where the steam injected from the communication hole into the cavity has traditionally lost its escape route and stayed in the vicinity of the non-permeable skin, if the return pipe is provided, You can easily get out. Therefore, fusion defects and the like due to residual steam and condensed water in the cavity do not occur. On the other hand, in the foamed resin molded product with a skin, the vapor reaches all corners of the cavity due to the presence of the return pipe, so that the foaming and fusion of the resin particles are completed, the desired molded product is formed, and the skin does not peel off. . Then, the return pipe insertion hole remains in the foamed resin molded product, but since it is located on the back surface side hidden by the product, there is no problem.

[0009]

EXAMPLES The present invention will be described in detail below based on examples. (1) Example 1 Method for Manufacturing Foamed Resin Molded Product with Skin FIG. 1 to FIG. 3 show an example of a method A for manufacturing a foamed resin molded product with skin according to the present invention. 1 is a cross-sectional view of a foaming mold used for manufacturing a foamed resin molded product with a skin, FIG. 2 is a cross-sectional view around the cavity and the supply feeder of FIG. 1, and FIG. 3 is a perspective view of the return pipe of FIG.

First, the foaming mold 1 used in the manufacturing method of the present invention will be described. The horizontal foaming mold 1 is composed of a set of a core mold 11 and a cavity mold 12, and each has box-shaped steam chambers 13 and 14 to which a steam pipe 2 is connected (FIG. 1). The mold surfaces of the core mold 11 and the cavity mold 12 forming the cavity 15 have a large number of communication holes 111, 121 penetrating to the steam chambers 13, 14. This communication hole 11
The pore diameters of 1,121 are smaller than the diameter of resin particles used as the raw material of the foamed resin molded product with skin 7.

A raw material filling machine (not shown) is used for the core mold 11.
A supply feeder 4 is provided for feeding the expandable resin particles 3 into the cavity 15 (FIG. 2). Further, the pipe-shaped return pipe 5 is arranged so as to project into the cavity 15 and attached to the core mold 11. The return pipe 5 goes out of the core mold 11 and is connected to the vacuum pump 8.

In this embodiment, three return pipes 5 extend from the header 6 to near the mold surface of the cavity mold 12. The interval between the return pipes 5 is within 150 mm, preferably within 80 mm. The set number of return pipes 5 is appropriately determined according to the three-dimensional shape of the foamed resin molded product with the skin. However, the insertion hole 711 of the return pipe 5 is formed on the rear surface of the foam 71 after molding.
Therefore, it is more desirable to increase the number of return pipes 5 than to increase the diameter thereof. In the foaming mold 1, the diameter of the return pipe 5 is 6 mmφ.

The distance between the return pipe 5 and the skin 72 set in the cavity mold 12 is 10 to 60 mm, preferably 20 to 40 mm. This is because if the distance between the return pipe 5 and the skin 72 is too close, it becomes difficult to fill the resin particles 3 and steam easily causes wrinkles, swelling, and the like on the skin 72.
Further, if the distance between the tip of the return pipe 5 and the skin 72 is too narrow, there is no room for the resin particles 3 to enter, and a cavity is formed on the back surface side of the skin 72. On the contrary, the upper limit is set because if the distance between the return pipe 5 and the skin 72 is too large, the uneven distribution of the resin particles 3 and vapor at the time of filling will cause the skin 7
This is because the resin particles 3 are not spread close to 2 and fusion of the resin particles 3 is insufficient. In the foaming mold 1, the distance between the return pipe 5 and the skin 72 is 20 mm.

Each of the return pipes 5, as shown in FIG.
A net 52 through which the resin particles 3 do not pass through the tip opening 51.
And a plurality of through holes 53 are formed on the peripheral surface of the pipe arranged in the cavity 15. The opening diameter (0.8 mmφ) of the through hole 53 is the diameter of the resin particle 3 (about 2 to 6 mmφ).
Smaller than If the inner diameter of the return pipe 5 is smaller than the resin particle diameter, the net 52 becomes unnecessary. The return pipe 5 may be either a type having only the opening 51 at the tip or a type having a through hole 53 in the entire pipe. However, it is preferable to increase the number of the through holes 53 as shown in FIG. This is because the suction force is increased as it approaches the tip of the return pipe 5, so that the filling and fusion of the resin particles 3 near the tip can be promoted, and the filling failure and the fusion failure can be eliminated.

By the way, the return pipe 5 and the core mold 11 need not be sealed. If the resin particles 3 do not come out of the mold, it is preferable that there is clearance. This is because such a clearance plays the same role as the communication hole 111.

Next, a method of manufacturing a foamed resin molded article with a skin using the foaming mold 1 will be described. Expandable resin particles 3
For this, a granular polypropylene resin impregnated with a foaming gas was prefoamed with a prefoaming machine at a magnification of 30 times. As the skin 72, a non-breathable polypropylene sheet (thickness of 0.1 to 2.0 mm) was used. here,
The resin particles 3 may be a one-stage foamed product, but it is preferable to use pre-expanded particles in order to obtain the foamed body 71 having a higher heat retention effect. The material of the expandable resin particles 3 is polypropylene, polyethylene, polystyrene, polyphenylene oxide, or the like. The material of the skin 72 is not only polypropylene but also a resin film such as vinyl chloride resin or polyethylene.

In the production of the foamed resin molded article with the skin, the following steps are repeated every cycle. First, the core mold 11
On the (fixed side) mold surface, 72 sets of pre-shaped skins are formed. Next, the cavity mold 12 (moving side) is moved to the core mold 11
To close the mold (Fig. 1). And
Raw material filling machine (not shown) without opening the hopper shutter
Fill air from the cavity through the feeder 4
Blow in. This is for removing water drops on the foamed mold surface. Then, the resin particles 3 are filled in the cavity 15. The resin particles 3 are sent into the cavity 15 by jetting the carrier air (FIG. 2).

Here, the vacuum pump 8 connected to the return pipe 5 is started at the same time as the filling of the resin particles 3 is started. By this vacuum suction, the air entrained together with the resin particles 3 into the cavity 15 passes through the return pipe 5 and the cavity 1
5 is discharged to the outside. The suction pressure (vacuum degree) of the vacuum pump 8 is 750 mmHg VAC.

Pulsating suction is performed at the beginning of the filling of the resin particles 3. This is because the resin particles 3 are less likely to be clogged in the through holes 53 of the return pipe 5 by the pulsating suction, and the suction effect is enhanced. In addition, the resin particles 3 can reach the vicinity of the skin 72 without forming a cavity near the skin 72. Thus, the entrained air of the resin particles 3 as shown in FIG.
The air flows toward the tip of the return pipe 5, and the air passes through the through hole 53.
Is sucked from. The resin particles 3 are smoothly filled from the back surface of the skin 72. Since the through holes 53 are formed on the peripheral surface of the return pipe 5, the filling is made uniform. still,
If the return pipe 5 itself is vibrated, rotated, etc., the resin particles 3 can be filled more quickly and evenly, which is preferable.
When the filling of the resin particles 3 in the cavity 15 is almost completed, the suction is changed to continuous suction, and the carrier air of the resin particles 3 is expelled from the return pipe 5 to the outside of the system. Since the return pipe 5 is arranged so as to project into the cavity 15, even if the non-air-permeable skin 72 is used, the communication hole 11 of the core mold 11 as in the conventional case.
The resin particles 3 are not unevenly distributed in 1 and the cavity 15 can be filled with a predetermined amount.

Next, the mold clamping operation is performed, and then the valves (not shown) of the steam pipes 2a and 2b are opened, and the core mold 11,
Steam is allowed to flow into the steam chambers 13 and 14 of the cavity mold 12. The steam used has a pressure of 4 kg / c on the steam pipe 2a side.
The m ² temperature was about 143 ° C., the steam piping 2 b side was lower than this, and the pressure was 1.5 kg / cm ² and the temperature was 110 ° C. When the pressure on the cavity mold 12 side becomes high, the force pushing the skin 72 from the outside to the inside works, and the skin 7
This is because it causes a problem that wrinkles and the like are formed on the second sheet. Further, when the temperature of the cavity mold 12 side becomes high, the skin 72
This is because there is a risk of softening.

Preheating is first carried out with steam. The temperature of the foaming mold 1 rises by preheating. At this point, vacuum pump 8
Works, and the accumulated steam and condensed water are also drained. The vacuum pump 8 is intermittently operated to suck the accumulated steam or the like from the return pipe 5. After that, the operation is shifted to continuous suction, and the removal of accumulated steam and the like is completed.

Next, main heating is started. Steam is flowed into the cavity 15 to heat and fuse the resin particles 3. During the main heating, the vacuum pump 8 uses pulsating suction to promote fusion. The heated steam penetrates deep into the cavity 15 to the vicinity of the skin 72 and applies heat of fusion to the resin particles 3. And
The steam and condensed water, which have exhausted the latent heat and finished their functions, are sucked up by the return pipe 5 arranged up to the vicinity thereof and discharged to the outside of the cavity 15. By the pulsating suction operation, the steam inflow into and out of the cavity 15 smoothly proceed.

At this stage, a steam flow is formed throughout the cavity 15. That is, the steam room 13,1
At the same time as 4 is heated, the heated steam enters between the resin particles 3 and 3 through the communication hole 111. Then, the resin particles 3 are heated while expelling the residual air between the resin particles 3 and 3. After that, the steam and condensed water that have been heated are returned to the return pipe 5.
Is sucked into. By the above operation, the resin particles 3 become soft, and the resin particles 3, 3 are changed into the foamed body 71 which is fusion-bonded to each other. At the same time, by heating and fusing the resin particles 3, the skin 72 is adhered and bonded to the molding surface. Thus, a foamed resin molded product with a skin in the shape of the cavity 15 is completed. When this molding is completed, the steam is stopped and the vacuum pump 8 is also stopped. The expansion ratio of only the molding foam is about 1.1 to 1.8.

After that, cooling and cooling operations are started. Core type 1
1. Cooling water is circulated in a cooling water pipe (not shown) arranged in the cavity mold 12 to lower the temperature. Further, in parallel with the above operation, cooling air is taken in through the drain ports 16 and 17. Then, the vacuum pump 8 is restarted to draw the cool air into the cavity 15 and remove the heat of the cool air from the return pipe 5 to the outside of the system one after another. This is because the cooling time can be shortened. In this way, the molding and foaming is completed, and the process proceeds to the next mold opening. After the mold is opened, finally, the eject pin (not shown) advances to take out the desired foamed resin molded product with the skin.

Foamed Resin Molded Product with a Skin A foamed resin molded product with a skin 7 obtained by the above-mentioned manufacturing method is shown in FIG. The foamed resin molded product 7 with a skin has a foamed body 71 formed by mutual fusion bonding of the resin particles 3 which are expanded by heating with steam, and a skin 7 which is adhesively bonded to the outer surface of the foamed body 71.
It consists of 2. The skin 72 is integrated with the foam 71 when the resin particles 3 are fused. Therefore, the adhesion strength between the foam 71 and the skin 72 is large. The foam 71 is a cavity-shaped molded product made of expanded polypropylene, and is lightweight and highly heat-retaining. Three insertion holes 711 for the return pipe 5 are formed on the back surface side of the foam body 71.

The insertion hole 711 is formed from the back surface of the foam body 71 to the skin 72 until a distance of about 20 mm is approached. Therefore, as the thickness of the foam 71 increases, the insertion hole 711
Too deep. By forming the insertion hole 711, the resin particles 3 are filled up to the vicinity of the skin 72, and the unevenness of steam heating is eliminated. As shown in FIG. 4, the foamed resin molded product with a skin 7 in which the foam 71 and the skin 72 are integrated has an insertion hole 71.
Due to the presence of the return pipe 5 disposed in No. 1, defects such as formation of a hollow portion in the foam 71 and peeling or swelling of the skin 72 are eliminated.

By the way, the insertion hole 711 is a circular hole,
It is preferable that the foam body 71 is tapered slightly toward the outer surface 72. This is because the return pipe 5 can be easily separated from the foam body 71. A non-breathable skin 72 covers the required parts of the foam 71 and its outer edge 7
21 is extended. A desired final product is completed by cutting off the outer skin edge 721 of the foamed resin molded product with a skin 7 in a post-process.

(2) Example 2 Compared to Example 1, a foamed resin molded product with a skin 7 having a relatively simple structure is produced (FIGS. 5 and 6). Therefore, the number of the return pipes 5 protrudingly arranged in the cavity 15 of the foaming mold 1 is two. In addition, the cavity mold 12 has the first embodiment.
Such a communication hole 121 is not formed. Since the non-air-permeable skin 72 blocks the mold surface of the cavity mold 12 by disposing the non-air-permeable skin 72, the vapor from the cavity mold 12 may directly contact the resin particles 3. Because there is no. The other components and manufacturing method are the same as in the first embodiment. FIG. 6 shows a foamed resin molded product with a skin 7 obtained by the foaming mold 1 of Example 2. The surface of the foam 71 is covered with the skin 72. Then, an insertion hole 711 is formed on the back surface side where it is hidden when the product is manufactured. Reference numeral 721 is an outer edge of the epidermis that is cut off when the product is manufactured.

(5) Effects of the Embodiments According to the foamed resin molded article with the skin and the method of manufacturing the same in the above-described manner, since the return pipe 5 is arranged so as to project into the cavity 15, the non-permeable skin 72 is formed. Even when it was arranged on the mold surface of the cavity mold 12, the air could be properly discharged when the resin particles 3 were supplied. By connecting the return pipe 5 to the vacuum pump 8 and applying vacuum suction, the entrained air could be more efficiently removed from the return pipe 5 to the outside of the cavity 15. In addition, since the return pipe 5 is provided up to the vicinity of the skin 72, the resin particles 3 easily enter the back surface of the skin. Similarly, even when steam heating the resin particles 3 to fuse them, the steam and condensed water that have finished their roles can be quickly removed from the system through the return pipe 5 by vacuum suction, so that the resin particles 3 are foamed and expanded. The fusion was surely achieved. As described above, the suction and discharge of air and vapor from the return pipe 5 are achieved, so that the non-breathable skin 72 is formed into the foam type 1.
However, the defective filling of the resin particles 3, the peeling of the outer skin 72, the wrinkles and the like disappeared. Then, the foamed resin molded product with a skin 7 having a desired excellent quality could be easily manufactured.

Further, during cooling, the air in which cold air is taken in from the drain port 16 can be sucked out from the return pipe 5, which contributes to shortening the cooling time. Further, the pulsating suction of the vacuum pump 8 alleviates the clogging of the resin particles 3 into the through holes 53,
A foamed resin molded product with a skin 7 having stable and excellent quality could be manufactured. In addition, a change in the shape of the foam body 71 can be dealt with by appropriately selecting the number of the return pipes 5 and the like.
There were no restrictions on product shape, thickness, etc. By the way, the insertion hole 711 of the return pipe 5 is formed in the product,
Since it is located on the back surface of the foam 71 that is invisible to the public, there is no problem.

The present invention is not limited to those shown in the above embodiments, but can be variously modified within the scope of the present invention depending on the purpose and application. For example, the material of the skin 72 and the foam 71,
The shape and the like are appropriately selected according to the application. A pigment, an antistatic agent, a heat stabilizer, and the like are added to the foam 71 as needed. The epidermis 72 is not limited to the use of non-breathable epidermis, but also includes application to breathable epidermis. This is because even in the case of a breathable skin, the shape of the foam 71 may be too complicated to cause uneven filling of the resin particles 3, defective fusion, and the like, and in such a case, it is effective. Further, even when the skin 72 is not provided, it may be applied in order to prevent defective fusion or the like. The foaming mold 1 may adopt a vertical shape instead of a horizontal shape.

[0032]

INDUSTRIAL APPLICABILITY As described above, the foamed resin molded article with the skin and the method for producing the same according to the present invention are integrated with the skin which enhances the heat retention efficiency and helps prevent the occurrence of mold, without the inside of the foam being defective or the fusion being defective. Since it is used to manufacture a molded foam, it contributes to improving the performance and quality of the product, and also has an excellent effect in that the manufacturing process is simplified and an inexpensive product can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view of a foaming mold of Example 1.

FIG. 2 is a cross-sectional view around the cavity and supply feeder of FIG.

3 is a perspective view of the return pipe of FIG. 1. FIG.

FIG. 4 is a perspective view of a foamed resin molded product with a skin obtained by the foaming mold of Example 1.

FIG. 5 is a sectional view of a foaming mold of Example 2.

FIG. 6 is a perspective view of a foamed resin molded product with a skin obtained by the foaming mold of Example 2.

FIG. 7 is an explanatory sectional view of a conventional technique.

FIG. 8 is an explanatory cross-sectional view of a conventional technique.

FIG. 9 is an explanatory cross-sectional view of a conventional technique.

FIG. 10 is an explanatory cross-sectional view of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Foaming type 15 Cavity 3 Resin particles 5 Return pipe 7 Foamed resin molded product with a skin 71 Foam 711 Insert hole 72 Skin

Claims (2)

[Claims] 1. A foam (71) formed by fusing expandable resin particles with steam as a heating medium, and a skin (7) attached to the outer surface of the foam by fusing the resin particles. 72), and a foamed resin molded article with a skin, characterized in that an insertion hole for a vapor return pipe for heating the resin particles toward the inside of the foam is formed on the back surface side of the foamed body. . 2. A method for producing a foamed resin molded article with a skin, wherein the outer surface of a foam is covered with a skin, the method comprising the steps of disposing a skin on a foam mold, closing the mold, and then foaming into the cavity by air conveyance. -Like resin particles are injected, and the entrained air is discharged to the outside of the cavity using a return pipe protruding in the cavity, and then steam is supplied into the cavity to promote heat fusion of the resin particles, while returning to the above A method for producing a foamed resin molded article with a skin, which comprises forming a foam integrated with a skin by discharging steam and its condensed water from a pipe to the outside of the cavity.