JPH06339935A - Foam molding tool - Google Patents

Abstract

PURPOSE:To provide a foam molding tool which can control the generation of flashes and degassing securely and simply without being affected by thermal deformation and the like on the peripheral edges of a skin. CONSTITUTION:In a foam molding tool consisting of a cover mold 21 and a cavity mold 11 with a skin disposed thereon and molding a foaming raw material in a cavity 30 between the inner face of the cover and the inner face of the skin, sealed faces 15 and 23 clamping the peripheral edge of the skin on the inner face of the cover mold and the inner face of the cavity on the cavity outer periphery, and vent hole channels 26 with their one ends 27 opened in the cavity and the other ends 28 communicating with the outside of a foam molding tool are formed on the sealed faces 23 of the cover mold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foaming mold comprising a lid mold and a cavity mold in which a skin is arranged.

[0002]

2. Description of the Related Art As a method for producing a foam-molded article in which a foam is covered with a skin, a skin-integrated foam-molding method is widely used. This skin-integrated foam molding method uses a foam molding die composed of a lid mold and a cavity mold, and a foaming raw material such as a polyurethane raw material is injected into a cavity between the skin and the lid mold arranged in the cavity mold so as to be integrated with the skin. This is a method of foaming. In addition,
Depending on the application of the foam-molded article, a base material may be placed in the lid mold to foam the skin and the base material together.

The foaming raw material injected into the cavity in the skin-integrated foam molding method fills the cavity by the foaming reaction to form a cavity-shaped foam and is integrated with the skin (and the base material when there is a base material). Into a desired foam-molded product. At that time, if the air remaining in the cavity or the foaming gas generated from the foaming raw material is trapped in the cavity, the foaming foaming raw material cannot fill the inside of the cavity without any gap, and the foamed molded product has a shortage or Voids (air pockets) occur, and good products cannot be obtained.

In order to prevent the defective molding, it has been proposed to allow air or foaming gas in the cavity to escape to the outside of the mold by providing a gap between the closing surfaces of the lid mold and the cavity mold (see Japanese Patent Publication No. 63-286786). ). It has also been proposed to timely seal the gap between the lid mold and the cavity mold during foam molding (see Japanese Utility Model Publication No. 4-5288).

However, in the former case, the foaming raw material is likely to leak from the gap of the closing surface to cause burrs, resulting in loss of the foaming raw material,
The burr removal work after molding was unavoidable. In addition, when the skin is placed, the peripheral edge of the skin may be deformed or lifted up, or after the skin is placed, the heat or foaming pressure of the foaming raw material may deform or lift the peripheral edge of the skin. There is a risk that gas will not escape.

Further, in the latter case, there is a problem that if the sealing time is wrong, air or the like will be left in the cavity and a void or void will be formed in the foam. In particular, since the rate of the foaming reaction of the polyurethane raw material is likely to change depending on the liquid temperature, it is easily affected by the ambient temperature, and it is extremely difficult to measure the sealing time.

[0007]

SUMMARY OF THE INVENTION Therefore, the present invention has been made in view of the above points, and provides a foaming mold capable of reliably and easily degassing while suppressing the generation of burrs.

[0008]

The present invention provides a foaming mold comprising a lid mold and a cavity mold in which a skin is arranged, wherein a foaming raw material is foamed in a cavity between the lid mold inner surface and the skin inner surface. A sealing surface sandwiching the peripheral edge of the skin is formed between the inner surface of the lid die on the outer periphery of the cavity and the inner surface of the cavity die, and one end of the sealing surface of the lid die opens in the cavity and the other end communicates with the outside of the foam molding die. The present invention relates to a foaming mold having a gas vent groove.

[0009]

[Function] The skin placed in the cavity mold during foam molding is
The peripheral edge is sandwiched by the sealing surfaces of the lid mold and the cavity mold to be sealed. However, the sealing surface of the lid mold has a gas vent groove that connects the inside of the cavity to the outside of the foam molding die, so even if the lid mold and the cavity mold are completely closed, the gas vent groove creates a foam vent inside the cavity. The outside of the mold is communicated with, and the air and foaming gas in the cavity are discharged to the outside of the cavity through the gas vent groove.

Further, since the outer peripheral edge is sandwiched between the sealing surfaces, the outer peripheral edge is securely fixed to prevent deformation of the outer peripheral edge, and one end of the gas vent groove is open in the cavity. Even if the skin is deformed by heat or the like, the gas vent groove is not blocked by the deformation of the skin. As a result, stable degassing can always be performed. In addition, since the foaming raw material increases in viscosity as the foaming reaction proceeds, it is difficult for the foaming raw material to leak out of the cavity through the narrow gas vent groove, and there is almost no possibility of forming burrs.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. 1 is a sectional view of a foaming mold of the present invention, FIG. 2 is a sectional perspective view showing a part of a lid mold thereof, FIG. 3 is a partially enlarged sectional view of a foaming mold at the time of foam molding, and FIG. 4 is foaming of the present invention. FIG. 3 is a cross-sectional view of a foam-molded product obtained by using a molding die.

The foaming mold 10 of this embodiment comprises a cavity mold 11 and a lid mold 21, and has a cavity 30 between the inner surface of the cavity mold 11 and the inner surface of the lid mold 21. Further, there is a gap 31 between the closing surface 12 of the cavity mold 11 and the closing surface 22 of the lid mold 21.

The cavity mold 11 is also called a lower mold, and in this embodiment, the upper parts are split molds 13 and 14 in order to eliminate the undercut shape when the foam molded article is removed from the mold. A sealing surface 15 is formed on the outer periphery of the cavity 30 in the cavity mold 11. The sealing surface 15 is for sandwiching and sealing the peripheral edge 41 of the skin 40 arranged in the cavity mold 11 during foam molding with the sealing surface 23 of the lid mold 21 described later. This sealing surface 15,2
3 is not necessarily provided all around the outer periphery of the cavity 30, and may be provided only in a portion where the foaming raw material easily leaks during foam molding. In the figure, 16 and 17 are split molds 13,
A hinge for connecting 14 openably and closably, a mold closing surface 12
It is a protrusion for fixing the epidermis formed on the.

The lid mold 21, which is also called an upper mold, is connected to the cavity mold 11 by a hinge 19 and can be opened and closed. The inner surface of the lid mold 21 has a sealing surface 23 (FIG. 2) facing the sealing surface 15 of the cavity mold 11.
Then, a chain line portion) is formed on the outer periphery of the cavity 30, and an inner end portion of the gap 31 of the closing surface is formed on the outer side of the cavity 30 which is connected to the seal surface 23.

A gas vent groove 26 is formed in the sealing surface 23 of the lid mold 21. The degassing groove 26 has one end 27 opening into the cavity 30 and the other end 28 opening into the gap 31 so that the cavity 30 communicates with the outside of the foaming mold through the gap 31 when the mold is closed. is there. One end 27 of the gas vent groove 26 that opens in the cavity 30
Is preferably projected into the cavity 30 after the skin 40 is arranged. The protrusion amount a (shown in FIG. 3) is not particularly limited, but is usually about 2 mm to 10 mm. Further, the width t (shown in FIG. 2) and the depth d (shown in FIG. 3) of the gas vent groove 26 are usually preferably about 2 to 5 mm in order to prevent the foaming raw material from leaking out, while the distance b between the gas vent grooves 26 is set to b. (Shown in FIG. 2) is usually preferably about 10 to 20 mm.

It should be noted that the gas vent groove 26 must be the sealing surface 2
It does not have to be provided over the entire area of 3, and may be provided only in a part of the sealing surface 23, particularly in a part requiring degassing. Further, the interval b between the gas grooves 26 may be narrowed in a portion where it is desired to make the gas release exceptionally good.
Further, the cross-sectional shape of the gas vent groove 26 is not limited to the concave shape shown in the drawing, but may be a semicircular shape or the like.

The foam molding die 10 thus formed is used as follows during foam molding. First, the lid mold 21
A skin 40 having a predetermined shape is placed on the inner surface of the cavity mold 11 in the opened state. At that time, the peripheral edge 41 of the skin 40
The end portion 41a is arranged on the mold closing surface 12 of the cavity mold, and the seal portion 41b inside the end portion 41a is arranged on the seal surface 15 of the cavity mold. Then, the outer peripheral edge portion 41
The positioning concave portion 42 provided in a is a protrusion of the closing surface.
, So that the skin 40 is properly placed in the cavity mold 11. As the skin 40, various types such as a plastic skin formed into a predetermined shape by vacuum forming or slush forming, or a laminated skin formed by laminating a plastic film or flexible foam on a fabric to form a predetermined shape are foamed products. It is used according to the application.

On the other hand, a mold release agent such as silicon emulsion is applied to the inner surface of the lid mold 21 including the sealing surface 23 and the degassing groove 26. Further, in this embodiment, the lid type 2
The base material 50 is arranged on the inner surface of the substrate 1 via a clip, a magnet or the like (not shown). The base material 50 has a size such that the edge portion 51 does not close the one end 27 of the gas vent groove. This base material 50 is also called an insert and is used for imparting rigidity to or attaching to the foam molded product, and may not be necessary depending on the application of the foam molded product.

Next, the cavity 30 in the skin 40.
A foam material such as polyurethane material is injected into the lid mold 2
1 is closed. With this closed mold, the seal portion 4 around the epidermis is
1b is a cavity type sealing surface 15 and a lid type sealing surface 2
3, the outer peripheral edge 41 is fixed and sealed. At this time, one end 27 of the gas vent groove 26 on the lid-shaped sealing surface 23 has a cavity 30 inside the skin 40.
The inside of the cavity 30 is opened, and the other end 28 is opened at the inner end of the gap 31 of the mold closing surface to connect the inside of the cavity 30 to the outside of the foam molding die 10.

The foaming raw material injected into the cavity foams and fills the cavity 30 as shown in FIG. At this time, the air trapped in the cavity 30 at the time of the mold closing or the foaming gas generated by foaming is the foaming raw material 6
Cavity 30 through degassing groove 26 according to 0 fill
Are discharged from the foam molding die. Therefore, the foaming raw material 60 in the cavity 30 foams without being disturbed by the air or foaming gas remaining in the cavity,
Fill the cavity 30 without any gap. In addition, foaming raw material 6
In the case of 0, since the viscosity increases due to the progress of the foaming reaction and the fluidity deteriorates, it hardly penetrates into the narrow gas vent groove 26. Since the property is impaired, it hardly flows out to the mold closing surface through the gas vent groove 26.

The foaming raw material 60 filling the cavity is
Due to the adhesiveness at the time of foaming, it is integrated with the skin 40 and the base material 50 and cured to become a foam. After that, the lid mold 21 and the cavity mold halves 13 and 14 are opened, and the foamed molded product 70 shown in FIG. 4 is taken out. The foamed molded product 70 taken out has the peripheral edge 41 of the skin 40 cut and removed from the position indicated by the chain line, if necessary. Reference numeral 61 in the drawing denotes a foam formed from the foaming raw material 60.

In the above embodiment, a gap is provided in the mold closing surface and the gas vent groove is communicated with the outside of the foam molding die through the gap. The ends of the grooves may be opened on the outer surface of the foaming mold.
However, if the gas vent groove is communicated with the outside of the foam mold through the gap, the gas vent groove can be communicated with the outside of the foam mold even when it is difficult to directly open the gas vent groove on the outer surface of the foam mold.

Further, in the above-mentioned embodiment, the open pouring method in which the lid mold is opened to inject the foaming raw material is shown, but the present invention is not limited to this, and the foaming raw material is injected with the lid mold closed. A closed injection method may be used. Further, the cavity mold is not limited to the split mold as in the above embodiment, but may be a single cavity mold depending on the shape of the foamed molded product.

[0024]

As shown and described above, according to the present invention, a sealing surface sandwiching the skin peripheral edge is provided in the lid mold and the cavity mold, and the sealing surface of the lid mold communicates the inside of the cavity with the outside of the foaming mold. Since the gas venting groove is provided, the air in the cavity or the foaming gas can be discharged to the outside of the cavity during foam molding, and a good foam molded product with no wall thickness or air retention can be obtained.

Moreover, since the outer peripheral edge is sandwiched between the sealing surfaces and one end of the gas vent groove is opened in the cavity, the vicinity of the outer peripheral edge is not deformed and the gas vent groove is not blocked, so that the gas vent can be reliably performed. Can be pulled out.

Further, since the foaming raw material increases in viscosity and decreases in fluidity due to foaming, there is little risk of leakage through the gas vent groove, and burrs hardly occur. Therefore, according to this foaming mold, not only the raw material can be saved, but also the burr removing work after the molding can be simplified.

[Brief description of drawings]

FIG. 1 is a sectional view of a foaming mold according to an embodiment of the present invention.

FIG. 2 is a cross-sectional perspective view showing a part of a lid mold of the foaming mold.

FIG. 3 is a partially enlarged sectional view of the foam molding die during foam molding.

FIG. 4 is a sectional view of a foam-molded article obtained by using the foam-molding die.

[Explanation of symbols]

 10 Foaming Mold 11 Cavity Mold 12 Cavity Mold Closing Surface 15 Cavity Mold Sealing Surface 21 Lid Mold 22 Lid Closing Surface 23 Lid Mold Sealing Surface 26 Venting Groove 30 Cavity 31 Gap 40 Skin

Claims (2)

[Claims] 1. A foam molding die comprising a lid mold and a cavity mold in which a skin is disposed, wherein a foaming raw material is foamed in a cavity between the inner surface of the lid mold and the inner surface of the skin, wherein the inner surface of the lid mold around the outer periphery of the cavity. A sealing surface that sandwiches the peripheral edge of the skin is formed on the inner surface of the cavity mold, and one end is opened in the cavity and the other end is formed with a gas vent groove that communicates with the outside of the foaming mold on the sealing surface of the lid mold. A characteristic foaming mold. 2. The method according to claim 1, wherein a gap is provided between the mold closing surface of the lid mold and the cavity mold outside the sealing surface, and the degassing groove is communicated with the outside of the foam molding die through the gap. Foam mold to do.