JPH11953A - Skin integrated bead expanded product and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacture of a skin integrated bead expanded product which is light weighted, excellent in an aethetic appearance, and ready to be recycled by a small process wherein shape reproducibility is good, and bond treatment is not required. SOLUTION: A powder slush molded skin 2 is set in bead expansion molding dies 11, 12, the dies 11, 12 are closed, and preliminarily expanded beads 6 prepared by expanding non-expanded particles are filled in the closed dies 11, 12. Then, steam is passed between the beads to execute steam heating, the beads are mutually fused, and a bead expanded body 7 is stuck onto a rear surface of the powder slush molded skin 2. Then, the dies 11, 12 are cooled, the molded product is taken out from the dies 11, 12, and the molded product is cured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foam-integrated bead foam product comprising a bead foam as a core and a powder slush-molded skin integrally fixed to the surface thereof, and a method for producing the same. This foamed product with an integral skin bead can be suitably used mainly as an automobile interior product such as an instrument panel.

[0002]

2. Description of the Related Art In recent years, in response to the demand for improved fuel efficiency of automobiles for the purpose of protecting the global environment, the weight reduction of automobile parts has been promoted. Attention has been paid to products using bead foams, which have high rigidity and are inexpensive and easy to form complex shapes (see Japanese Patent Application Laid-Open No. 5-229,034). However, this bead foam is an aggregate of individual foam beads, and there are local density differences and voids on the surface,
Lack of surface smoothness. Therefore, in order to obtain a product with design properties, the surface must be processed (Japanese Unexamined Patent Publication No. 7-2851).
No. 41), an epidermis is adhered to the surface (Japanese Unexamined Patent Publication No.
No. 229034).

However, in the above-mentioned surface processing method (see Japanese Patent Application Laid-Open No. 7-285141), the surface of the bead foam is heated and pressed with a heated metal plate or the like to form a non-foamed layer on the surface. Although a design is transferred from a metal plate, transfer of a fine pattern is limited, and there is a problem that a soft feeling cannot be imparted.

[0004] Further, a method of attaching a skin to the surface (see Japanese Patent Application Laid-Open No. 5-229034) is to apply an adhesive to the surface of a foam molded article molded in a mold by a bead method, and place a resin sheet on the surface. In this case, the bead foam and the sheet are adhered to each other at the same time as the vacuum forming of the sheet by setting it in a vacuum forming die.

[0005] In recent years, there has been an increasing demand for materials having good recyclability.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a skin-integrated bead foam product that is lightweight, has an excellent aesthetic appearance, and is easy to recycle.
An object of the present invention is to provide a manufacturing method which has good shape reproducibility and can be formed in a small number of steps without the need for an adhesive treatment.

[0007]

The invention according to claim 1 includes (a) a step of setting a powder slush-molded skin on a bead foam molding mold and closing the mold, and (b) placing the powder slush molded skin in the closed mold. Filling the pre-expanded beads obtained by expanding the non-expanded granules, (c) performing steam heating by passing steam between the beads to fuse the beads together, and to form a bead foam on the back surface of the powder slush molded surface. (D) cooling the mold and removing the molded body from the mold, and (e) curing the molded body.
The powder slash molded skin has a leather grain,
Fine processing such as cloth grain, stitching and matting can be performed, and it is excellent in appearance and touch. The powder slush molded skin is set on the inner surface of the mold by means such as vacuum suction. The material of the powder slush molded skin is olefin-based thermoplastic elastomer (TPO),
There are styrene-based thermoplastic elastomer (TPS), urethane-based thermoplastic elastomer (TPU), polyester-based thermoplastic elastomer, and the like. Fill the pre-expanded beads with 105-110% of the cavity volume of the mold.
The material of the pre-expanded beads is polypropylene (PP),
Modified polypropylene (PPO), polystyrene, polystyrene, polyphenylene oxide, and the like, and alloys thereof are included. The particle size of the non-foamed pellets composed of these is about 1.8 mm (1.5 to 2.0 mm), and bubbles are generated and grown by adding an additive agent and a foaming agent to about 30 times (20 to 50 times). Pre-expanded beads having a particle size of (×) are formed. Since the beads contain normal hexane as a foaming agent, they evaporate under normal pressure.
It is stored in a pressurized tank (about 0.3 to 5.0 kgf / cm ² (normal state (atmospheric pressure) is set to 0, the same applies hereinafter)).
Steam heating is performed at a steam pressure of 3.0 to 3.5 kgf / cm ² and 10
Performed for ~ 30 seconds. Curing is performed by placing the molded body taken out of the mold in a room at 50 to 70 ° C for 12 to 24 hours to prevent sink and deformation of the bead foam. The bead foam can be formed into a thick wall, and is lightweight and rigid.
In-mold foam molding by the bead method does not require a large-scale apparatus, so that the mold cost can be reduced.
In addition, complicated shapes can be easily formed,
There is no need to cut the molded body or remove burrs. Unlike the conventional method of placing a completed bead foam in a vacuum mold, a completed skin is set in a mold, and then pre-foam beads are filled and fused. Therefore,
Unlike the prior art, the uneven surface of the cured bead foam does not damage the skin and has good shape reproducibility. Further, there is no need to attach the skin to the surface of the bead foam, and the number of steps is reduced.

According to a second aspect of the present invention, in addition to the first aspect, the powder slush molded skin is
It is made of an olefin-based thermoplastic elastomer. Olefin-based thermoplastic elastomer (TPO)
Easy to recycle.

According to a third aspect of the present invention, in addition to the first or second aspect, the powder slush molded skin comprises at least two layers having a surface layer and a foam layer. Gives a soft feeling due to the foam layer. The bead foam is molded at a lower pressure than other molding methods, and has less damage to the skin, including the foam layer. By providing a solid back surface layer on the back surface of the foam layer, damage to the skin is reduced.

[0010] According to a fourth aspect of the present invention, a powder slush molding surface formed in advance is set in a bead foam molding die, and a bead foam molding is fused to beads on the back surface of the powder slush molding surface. At the same time, it is attached and integrated. Powder slush molded skin is made from materials such as thermoplastic elastomers.
It is molded using an electroforming mold or the like, and its surface can be subjected to fine processing such as leather grain, cloth grain grain, stitching, matting, etc., so that it has excellent appearance and touch. The bead foam is excellent in weight reduction, soundproofness and heat resistance, can be formed into a thick wall, and is lightweight and has sufficient rigidity.

According to a fifth aspect of the present invention, in addition to the fourth aspect of the present invention, the powder slush-molded skin is T-shaped.
It is a PO. It is easy to recycle and does not require backside bonding.

According to a sixth aspect of the present invention, in addition to the fourth or fifth aspect, the powder slush-molded skin comprises at least two layers having a surface layer and a foam layer. It has a soft touch due to the foam layer.

[0013]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view of an embodiment of a method for producing a foamed product with an integral skin of the present invention, and FIG. 2 is an explanatory view of an embodiment of a foamed product with an integrated skin of the present invention.

In FIG. 2, the foam product with integral skin of the present invention comprises a core 1 and a skin 2. The core 1 is a bead foam, and the skin 2 is a powder slush molded body. These are integrally fixed without interposing an adhesive therebetween. In the illustrated example, the skin 2 is composed of three layers of a surface layer 3, a foam layer 4, and a back layer 5, but the present invention is not limited to the three layers, but is a single-layer product, a two-layer product, or four or more layers. Things are also possible. In addition, it is possible to have no foam layer, but by providing a foam layer having an appropriate thickness, a product can have a soft touch.

The core 1 is a bead foam made of polypropylene (PP), modified polypropylene (PPO), polyethylene, polystyrene, polyphenylene oxide, and alloys thereof. This bead foam is prepared by adding an additive agent and a foaming agent to non-foamed pellets in advance to generate and grow bubbles, and to prepare granular pre-foamed beads having a size of about 30 times (20 to 50 times). It is filled in a bead foam molding die, heated and pressurized, and the beads are fused together. It is thick and lightweight, can secure rigidity, and is excellent in soundproofing and heat resistance. The thickness of the core body 1 is about 5 to 100 mm, depending on the part to be used.

The skin 2 is formed by powder slush molding, and the surface layer 3 is a solid layer, and the surface thereof is subjected to fine processing such as leather grain, cloth grain grain, stitching, matting, etc. using an electroforming mold or the like. It can be applied and has excellent aesthetic appearance and touch. The foam layer 4 formed on the back surface of the surface layer 3
This is for imparting cushioning properties. Back layer 5
Has a role of protecting the foam layer 4 at the time of molding or the like with a solid layer, and may be omitted in some cases.

The material of each of the layers 3, 4, and 5 is selected from olefin-based thermoplastic elastomer (TPO), styrene-based thermoplastic elastomer (TPS), urethane-based thermoplastic elastomer (TPU), polyester-based thermoplastic elastomer, and the like. However, it is preferable to use an olefin-based thermoplastic elastomer (TPO) from the viewpoint of recycling. The surface layer 3 and the foamed layer 4 are preferably made of the same type of thermoplastic elastomer from the above-mentioned thermoplastic elastomers in consideration of the good adhesiveness between the layers. In consideration of the above, a material containing polypropylene (PP), polystyrene (PS), ABS resin, modified polyphenylene oxide, and a reinforcing filler such as talc and glass fiber are also preferable. Each layer 3, 4, 5
Although there are various thicknesses depending on the type of material and the setting of the soft feeling, the thickness of the surface layer 3 is 0.2 to 1.0 mm, the thickness of the foam layer 4 is 1.5 to 5.0 mm, and the thickness of the back layer 5 is approximately. , 0.4-1.2
mm.

The skin-integrated bead foam product of the present invention integrates a core 1 and a skin 2 having two different properties so as to make use of their respective characteristics, and is lightweight, strong, soundproof, heat-resistant and heat-insulating. It has excellent aesthetic appearance and touch.

Next, a method of manufacturing this product will be described. In FIG. 1, a mold used in this manufacturing method includes a core mold 11 and a cavity mold 12 and holds cavities 13 and 14 while forming vacancies 13 and 14 on the back side of the molds 11 and 12, and each slide is formed by a slide mechanism (not shown). Frames 15 and 16 for separating the molds 11 and 12 from each other, steam inlets 17 and 18 for supplying steam to the cavities 13 and 14, and water cooling pipes 19 and 20 provided in the cavities 13 and 14 are provided. Cooling water inlet 2 for supplying cooling water
1 and 22 are provided. Although not shown, an eject pin for extruding the molded body from the mold after molding,
A feeder for filling the pre-foamed beads, pores for supplying the vapor filled in the vacant space to the pre-foamed beads, and, in some cases, a vacuum suction port for adsorbing the powder slush molded skin. , As appropriate, or one or both molds.

Next, a manufacturing method using this mold will be described.
The powder slush-molded skin 2 formed in another step is set in the cavity mold 12 (or vice versa in some cases) in advance (see FIG. 1A). Molds 11 and 12 at this time
Is about 60-80 ° C. Next, molds 11 and 12
Is closed and pre-foamed beads 6 are filled (FIG. 1 (b)
reference). The amount of pre-expanded beads 6 to be filled is between 105 and 110% of the cavity volume. Next, the steam pressure was set to 3.0 from the steam injection ports 17 and 18 to the vacant chambers 13 and 14.
Inject steam to ~ 3.5 kgf / cm ² for 10-30 seconds. The vapor enters through the pores formed in the mold into the bubbles in the pre-expanded beads and the voids between the individual beads, causing the beads to fuse with each other and, at the same time, being adhered to the back surface of the skin 2 (FIG. 1 (c)) reference). Thereafter, cooling water is injected into the cooling pipes 19 and 20 from the cooling water inlets 21 and 22, and sprayed onto the dies 11 and 12 to cool and solidify the dies 11, 12 and the molded body 7, and demold ( (Refer to FIG. 1 (d).), Curing is promoted by placing in a room at 50 to 70 ° C. for 12 to 24 hours to cure and prevent sink and deformation of the bead foam.

In such a manufacturing method, a large-scale apparatus is not required, so that the mold cost can be reduced. In addition, it is possible to easily form a complicated shape, and it is not necessary to cut the molded body into a fixed size after molding or to remove burrs, and thus it is possible to suppress the manufacturing cost. Also, unlike the method in which the completed bead foam is placed in a vacuum mold, in the present invention, the previously formed skin 2 is set in the bead foam mold, and the bead foam 1 is later formed. While being molded, it is adhered to the back surface of the skin 2 by fusing, and the skin 2 is not likely to be damaged, and the shape reproducibility is good. The bonding process is reduced.

The material of the pre-expanded beads includes polypropylene (PP), modified polypropylene (PPO), polyethylene, polystyrene, polyphenylene oxide, and alloys thereof. The particle size of the non-foamed pellets composed of these is about 1.8 mm (1.5 to 2.0 mm), and bubbles are generated and grown by adding an additive agent and a foaming agent to about 30 times (20 to 50 times). Pre-expanded beads having a particle size of (×) are formed. Since the beads contain normal hexane as a foaming agent and evaporate under normal pressure, the beads are pressurized (about 0.3 to 5.0 kgf / c).
m ² ).

The formation of the powder slush formed skin composed of three layers having a foamed layer as shown in FIG. 2 is performed by the following steps.

A preheating step of raising the temperature of the slush molding die to an appropriate temperature; a step of adhering a material for the surface layer to the preheated die; a step of adhering a material for the foam layer to the back side of the surface layer; Attaching the material of the back layer to the mold, final heating to make each layer attached to the mold an optimal sheet and a uniform foaming state, cooling to cool each layer together with the mold, and demolding to remove each layer from the mold. It is a process.

In the preheating step, the mold for powder slush molding is preheated to 250 to 300 ° C., attached to the first powder box containing the material of the surface layer, rotated, and an appropriate amount is attached to the inside of the mold. . After removing the first powder box, an intermediate heating step may be inserted to increase the temperature of the mold depending on the heat retaining state of the mold and the cured state of the surface layer, but the optimal sheet in the final heating step Avoid overcure so that it is in a state.
Next, a second powder box containing the material of the foam layer is attached to the mold, and is similarly applied in an appropriate amount. If necessary, an intermediate heating step is inserted. Finally, a second powder box containing the material for the back layer is used to deposit a suitable amount of the material in the same manner.
By heating for 0 seconds, each layer is brought into an optimal sheet and uniform foam state, cooled, and demolded to obtain a powder slush molded skin.

[0026]

As described above, according to the first to third aspects of the present invention, the powder slush-molded skin formed in advance is set in a bead foam molding die, and the bead foam is adhered to the back surface of the bead foam. It is a manufacturing method that is configured to be fixed at the same time, unlike the method in which the skin is adhered to the previously formed bead foam, the surface of the bead foam that is cured and uneven first in the molding process A product having good shape reproducibility without damage and excellent aesthetic appearance and tactile sensation can be obtained. In addition, the bonding step is unnecessary, so that the number of steps can be reduced and the cost can be reduced. Even complicated shapes can be easily formed.

According to a fourth aspect of the present invention, there is provided a powder slush molded body comprising a powder slush molded skin and a bead foam which are integrated by the method of the first aspect. The bead foam is firmly adhered to the outer skin without impairing the excellent appearance and tactile sensation of the skin, and is thick, lightweight and rigid, and has excellent soundproofing, heat resistance and heat insulation. In addition, by using an olefin-based thermoplastic elastomer for the skin, recycling can be facilitated.

[Brief description of the drawings]

FIG. 1 is an explanatory view of one embodiment of a method for producing a foamed product with an integral skin according to the present invention.

FIG. 2 is an explanatory view of one embodiment of a foamed product with an integral skin of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core body (bead foam) 2 Skin (powder slash molding skin) 3 Surface layer 4 Foam layer 6 Pre-foamed beads 7 Molded body 11, 12 Mold

Claims (6)

[Claims] 1. (a) a step of setting a powder slush molded skin on a bead foam molding mold and closing the mold;
(B) a step of filling pre-expanded beads obtained by expanding non-expanded granules in a closed mold; and (c) performing steam heating by passing steam between the beads to fuse the beads together with each other. A step of attaching a bead foam to the back surface of the powder slush molded skin, (d) a step of cooling the mold and removing the molded body from the mold, and (e) a step of curing the molded body. To manufacture foamed product with integrated skin. 2. The method according to claim 1, wherein the powder slash-molded skin is made of an olefin-based thermoplastic elastomer. 3. The process for producing a foam-integrated bead foam product according to claim 1, wherein the powder slush-molded skin comprises two or more layers having a surface layer and a foam layer. 4. A pre-formed powder slush-molded skin is set in a bead foam molding die, and a bead foam-molded body is adhered to the back surface of the powder slush-molded skin at the same time as the beads are fused to each other. A skin-integrated bead foam product characterized by being integrated. 5. The foam-integral bead foam product according to claim 4, wherein the powder slush-molded skin is made of an olefin-based thermoplastic elastomer. 6. The foam-integral bead foam product according to claim 4, wherein said powder slush molded skin comprises at least two layers having a surface layer and a foam layer.