JPH03206B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an improved foam molding method, and more particularly, to an improved foam molding method for advantageously foam molding a foam product in which a predetermined insert is embedded without causing problems such as underfilling. It's about how to do it.

(Prior art and its problems) Integrated foam products, such as automobile headrests, have been used in various fields, in which a predetermined insert (core body) is embedded inside a foam body. Foamed products such as this are made by injecting a foaming material such as urethane into a predetermined foaming mold with the insert positioned inside the mold.
It is manufactured by a foam molding method in which the foaming raw material is foamed and filled into a mold. However, with this type of molding method, there is an inherent problem that underfilling occurs due to foaming gas, air inside the mold, etc. at the confluence point of the foam that is foaming and expanding on both sides of the insert. There is.

In other words, a predetermined foaming material injected through the injection hole of the foaming mold fills the mold while foaming and expanding, but at this time, the mold space on one side of the insert If the foam that foams and fills the mold space on the other side of the insert merges with the foam that foams and fills the mold space on the other side of the insert at the position of the mold part of the foam mold, the mating surface of the mold part Since the gas during foaming of the raw material and the air inside the mold escape to the outside through the gaps, the entire inside of the mold can be completely filled with the foam, resulting in a defect-free foamed product.
However, if the foaming raw material foams quickly in the mold space on either side of the insert, the confluence point of the foam will occur at a location away from the mold part. At such confluence points, foaming gas and air that have failed to escape from the mold parts accumulate and are compressed, preventing the filling of the foam, and during this time the foam hardens, resulting in underfilling. This results in a deterioration in the quality of the foamed product obtained.

Conventionally, countermeasures have been taken to prevent this by providing gas vent holes in areas of the foam mold where such underfilling is likely to occur, or by forming mold splits at those positions. All such measures have the following drawbacks. In other words, the area where underfilling occurs tends to change depending on the foaming conditions and other external factors, and it is difficult to determine the appropriate position because it needs to be folded into the mold. Since material also leaks, there are inherent problems such as the number of man-hours needed to treat the leaked foam and the need to treat the mold with a mold release agent to make it easier to remove the leaked foam. Furthermore, the position of the mold splitting part is of course limited by the mold structure, and the foam located at the vent holes and the mold splitting part becomes hard and protrudes onto the product surface as burrs, which deteriorates the appearance. There are also inherent problems such as an increase in the number of finishing steps required to remove such portions.

(Solution Means) Here, the present invention has been made against the background of the above-mentioned circumstances, and its feature is that foaming is performed in a state where a predetermined insert is positioned in the mold of a foaming mold. By injecting a raw material and causing the foaming raw material to foam and fill the mold, when a predetermined foamed product in which the insert is embedded is foam-molded, the foam material hangs down into the mold at the mold splitting part of the foam molding mold. A rectifying plate extending to the vicinity of the insert is provided, and the rectifying plate is used to prevent foaming and filling the mold space on one side of the insert from intruding into the mold space on the other side. The foamed materials filling both sides of the insert are arranged to merge at the current plate portion.

(Function) As described above, in the present invention, the foaming raw material foams faster in the mold space on one side of the insert placed in the mold of the foaming mold than on the other side, and the foaming material foams there. Even if the insert becomes full, such foam is blocked by the current plate to prevent it from climbing over the insert and entering the mold space on the other side. The confluence point of the foam that foams and fills on both sides of the insert is effectively defined by this current plate part, and since this current plate part is provided in the mold part, this mold Foaming gas and air inside the mold are effectively released to the outside through the split portion.

(Specific Configuration) Hereinafter, the configuration of the present invention will be explained in more detail with reference to the drawings.

First, FIGS. 1 and 2 show an example of a foaming mold that is suitably used for foaming a headrest according to the present invention. In these figures, 2 is a fixed mold, and a movable mold 4 is rotated clockwise by a lower hinge (not shown) to the fixed mold 2 to match the fixed mold 2 and the movable mold 4. A mold space 6 is formed inside the movable mold 4 for foam-molding a predetermined headrest. Further, in the mold space 6, an insert 10 having a stay 8 for a headrest is arranged. Further, 12 is a mold matching part (mold dividing part), and this mold matching part 1 extending in the vertical direction
2, the left and right fixed molds 2 and movable molds 4 are matched to form a foam mold. Furthermore,
An injection hole 14 for the foaming raw material to reach the mold space 6 is provided in the center of the upper part of the mold matching part 12, and an injection plug 16 is fitted into the injection hole 14 to close it. I'm starting to be able to push myself.

Further, two hinges 18, 18 are attached to the upper surface of the mold matching part 12 at the upper part of the fixed mold 2 on both sides so as to sandwich the injection hole 14, and furthermore, these two hinges 18, 18 can be rotated. A rectifying plate 20 is attached to the piece. Then, as shown in the figure, this rectifying plate 20 is made of a fixed mold 2 whose molds are matched.
It is adapted to hang down into the internal mold space 6 through the mold matching part 12 between the movable plate 4 and the movable plate 4, and its lower end extends to the vicinity of the insert 10 arranged in the mold space 6. It is extending. Therefore, the current plate 20 is positioned to partition the space above the insert 10, thereby separating the upper part of the mold space on one side of the insert 10 and the upper part of the mold space on the other side. It's starting to feel like a partition.

Note that the size of the current plate 20 is generally determined by the size of the mold space 6 of the insert 10, as shown in FIG.
The length is approximately equal to the width at , and a predetermined gap l is formed between the insert 10 and the insert 10 . Also, this gap: l
is provided to absorb variations in the placement position of the insert 10 and to prevent the foam layer formed around the insert 10 from falling off from the insert 10, and is intended to prevent the foam product from falling off. An appropriate gap will be selected depending on the situation, but generally the gap is about 3 to 5 mm.

Therefore, when performing foam molding using a foam mold having such a structure, first insert the insert 10 and the rectifying plate 20 into the foam mold formed from the fixed mold 2 and the movable mold 4 as shown in FIG. is placed, a predetermined amount of a predetermined foaming raw material, such as a urethane raw material, is injected from the injection hole 14, and after the injection hole 14 is closed with an injection plug 16, according to a conventional method. A foaming raw material such as a urethane raw material injected into the mold space 6 is foamed and expanded to fill the mold space 6.

At that time, even if the filling speed of the foam 22 that is foamed and expanded is different on both sides of the insert 10 positioned in the mold space 6 of the foam mold, the speed shown in FIGS. As if,
The foam 22 filling the mold space on one side is blocked by the rectifying plate 20 and does not cross over the insert 10 and invade the mold space on the other side. Foaming and filling in the mold space progresses, and the foamed materials 22 on both sides come to merge at the current plate 20 portion.

For this reason, the foam 2 on both sides of the insert 10
2 and 22 is always defined at the part of the mold matching part 12 where the current plate 20 is provided, and since the joining point is not formed anywhere other than this mold matching part 12, the insert The foaming gas and the air in the mold generated in the mold space on both sides of the mold 10 are removed between the mold mating part 12, and further between the rotating piece of the hinge 18 or the rectifying plate 20 and the mold mating surfaces of the fixed mold 2 and the movable plate 4. It will escape to the outside through the gap between the holes, and there will be no lack of thickness. In addition, such a current plate 20 can be installed in a location where there will be no defects when forming a foamed product, and therefore, the presence of the current plate 20 will not cause any defects in the resulting foamed product. It is possible to effectively avoid this.

Further, the current plate 20 can be suspended in the mold space 6 in various forms in the mold matching part 12 of the foam mold, but as in the illustrated example, it may be suspended through the hinge 18 or rather Hinge 1
In an integral structure in which the rotating piece 8 is extended into the mold, it is preferable to hang it, and by arranging the rectifier plate 20 through such a hinge 18, the inside of the mold space 6 of the foam molding mold is The removability of the foam-molded product obtained by foam-molding from the mold is improved. Due to the presence of the hinge 18, after the movable mold 4 is rotated to open the mold, when the foam molded product formed in the mold space 6 is released from the fixed mold 2, the current plate 20 This is because the foam molded product can be taken out very easily since it is rotated clockwise in the figure.

Furthermore, although the current plate 20 is configured as a single integral plate-like body in the above specific example,
Of course, there is no problem in constructing the structure with a plurality of plate-shaped bodies, and in the case where the stay 8 protruding outside the foam molding mold provided in the insert 10 interferes with the rectifying plate 20, such a stay It is also possible to take measures such as removing the 8 portions of the current plate 20 or curving the 8 portions of the current plate 20 of the stay 8. However, in the case where the stay is connected to an insert in a foam molded product after foam molding, such measures are not necessary at all, and furthermore, in a foam molded product that does not have such a stay. The situation is the same.

Although the configuration of the present invention has been explained in detail based on one specific example of the present invention, the present invention is by no means to be construed as being limited to such specific example, and within the scope of the invention. It goes without saying that the present invention can be implemented in forms with various changes, modifications, improvements, etc., and that the present invention includes such embodiments.
should be understood.

(Effects of the Invention) As is clear from the above description, due to the presence of the current plate in the method of the present invention, for example, the confluence of the foam filling both sides of the insert is always located in the mold part where the current plate is located. As a result of the stipulations, degassing within the mold can be effectively carried out, thereby making it possible to advantageously and stably prevent underfilling of products obtained by foam molding. Moreover, since the gas vent hole can eliminate the lack of thickness at the confluence point without the need for special mold separation, the installation of such a gas vent hole reduces the number of man-hours in the pre-process and post-process, and reduces mold separation. While avoiding problems such as increased man-hours in post-processing due to settings, it has become possible to design the foam mold freely.Moreover, since the rectifying plate can be installed in a position that does not cause any defects in appearance, it can be easily installed in other parts. The appearance of the product is improved, etc.
This invention has achieved a number of excellent effects, and this is where the great industrial significance of the present invention lies.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of a foam mold used for carrying out the present invention (I in FIG. 2).
Fig. 2 is an explanatory diagram of the main part of the -I cross section in Fig. 1, and Figs. 3 and 4 respectively show changes in the filling state of foam in the foam mold. FIG. 2 is a partial cross-sectional explanatory diagram corresponding to FIG. 1 for illustrating. 2: Fixed mold, 4: Movable mold, 6: Mold space, 8: Stay, 10: Insert, 12: Mold matching part, 1
4: Injection hole, 16: Injection plug, 18: Hinge, 20:
Current plate, 22: foam.

Claims (1)

[Claims] 1. A foaming raw material is injected into a foam mold with a prescribed insert positioned inside the mold, and the foaming raw material is foamed to fill the mold, thereby producing a prescribed foamed product in which the insert is embedded. When performing foam molding, a rectifying plate is provided at the mold splitting part of the foam molding die to extend into the vicinity of the insert, and the rectifying plate allows the foam to flow into the mold space on one side of the insert. A foam molding method characterized in that the foam filling the insert is prevented from entering the mold space on the other side, and the foam filling both sides of the insert join together at the rectifying plate portion.