JPH03132311A - Foaming mold - Google Patents

Abstract

PURPOSE:To prevent air permeable synthetic paper from coming up to the surface and thus enable an excellent foam to be formed by constituting that the peripheries of air permeable synthetic paper closing vent-holes are hold and fixed between a split mold including the vent-holes and the other split molds. CONSTITUTION:For forming a polyurethane foam, at first when molds 12, 14 are fabricated, an air permeable synthetic paper 15 is held and fixed between a split mold including the vent-holes 26 and the other split molds for closing the vent-holes 26 and then a polyurethane material is injected into a mold cavity 16 and foamed thereafter. At the time, gas and air come out of the foam and remaining in the mold run out from the vent-holes 26 through the air permeable synthetic paper 15. On the other hand, the polyurethane material is interrupted by the air permeable synthetic paper 15 and prevented from coming into the vent-holes 26 and in consequence foams in the mold cavity 16. And, when the foam is taken out of the mold after a lapse of predetermined time, a desired foam can be obtained.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a foam type polyurethane foam used as a cushion body for vehicle seats, seat parts, etc., and in particular, a vent hole for gas venting. Regarding the foam mold provided.

(Prior Art) Conventionally, polyurethane foams used for cushion bodies such as vehicle seats are molded by injecting a polyurethane raw material into a foam mold and foaming it into the shape of the mold surface.

By the way, in the foaming mold, the gases generated during foaming that do not contribute to the formation of the foam and the remaining air inside the mold are released outside the mold to prevent the formation of voids or voids in the resulting foam. Therefore, it is usually published in Japanese Unexamined Patent Publication No. 59-23
A vent hole for degassing as shown in Japanese Patent No. 2832 is formed.

However, although foaming molds with vent holes exhaust unnecessary gases, the expanding polyurethane raw material leaks out of the foaming mold through the vent holes, staining the outside surface of the mold, or clogging the vent holes. There are problems such as In addition, in a foaming mold whose vent hole is blocked due to the leakage during foaming, the internal pressure of the mold increases as the foaming progresses, and the foam that had been clogged in the vent hole is blown away by the internal pressure of the mold. The pressure inside the mold is released. Therefore, the sludge pressure in the foam acts toward the vent hole, and the cell membrane of the foam, which has not yet been sufficiently cured, ruptures, often creating cavities in the foam.

Therefore, Japanese Patent Application Laid-open No. 59-232832 proposes that by closing the opening inside the mold of the vent hole with a urethane foam sheet having an open-cell structure, only gas etc. can escape outside the mold, and the raw material to be knotted can be A molding method has been proposed in which the urethane foam sheet is impregnated and cured to prevent it from entering the vent hole.

However, in this method, the urethane foam sheet for closure is impregnated with the foaming raw material and cured, so the urethane foam sheet for closure is removed when the molded foam is removed. However, it is necessary to attach a foam sheet to the inner surface of the mold each time the molding is performed, and the workability and mass productivity tend to be poor, such as the number of man-hours required for the molding cycle being longer. However, the material impregnated into the urethane foam sheet is physically inhibited from foaming, resulting in the formation of hard spots in some parts of the foam, even on the back side, which can cause passengers to feel uncomfortable when sitting on the seat. There are also many.

Therefore, in order to solve the above-mentioned problem, the present applicant would like to invent a foam molding mold in which the vent hole is closed using breathable synthetic paper instead of the urethane foam sheet for closure (Japanese Patent Application No. 1-232250). .

Although the foam mold allows residual air in the mold and gas escaping from the foam to pass through, it hardly allows the liquid polyurethane raw material to pass through, so the raw material may leak out of the mold from the vent hole, or the vent hole may be blocked by leaked raw material. It never gets clogged. However, the foam mold has the advantage that it is not necessary to replace the synthetic paper for a certain period of time, making the foam molding operation extremely simple and improving the molding operation.

(Problem to be Solved by the Invention) However, if the vent hole is closed by pasting the breathable synthetic paper on the mold surface using a normal pasting means such as double-sided adhesive tape, then the breathable synthetic paper is Even when replacing the synthetic paper, it was far from easy to replace it.9Also, the mold surface on which the vent hole is provided is usually the mold surface that constitutes the back surface of the foam, but the weight of the foam In order to reduce the weight and save the original v1, a protrusion is provided on a part of the mold surface, so-called undercutting. Therefore, the protrusions may make it difficult for the breathable synthetic paper to adhere to the mold surface.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a foam mold that allows easy attachment and replacement of air-permeable synthetic paper that closes vent holes.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a foamed pen in which the split-type pen 1 provided with a vent hole is closed with breathable synthetic paper! , the type containing the vent hole is divided into v1
It is made of 1M construction, and the edge of the breathable synthetic paper that closes the vent hole is sandwiched and fixed between the split mold containing the vent hole and the remaining split mold. Furthermore, in addition to this, for foam molds in which part of the mold surface of the split mold including the vent hole is protruded due to the above-mentioned thinning, etc., the protrusion is made removable, and the removable protrusion mold A part of the breathable synthetic paper was sandwiched between the surfaces.

(Function) The edges of the breathable synthetic paper are clamped and fixed between the split mold including the vent hole and the remaining split mold, so that the breathable synthetic paper is affixed to the mold surface of the split mold including the vent hole. That lick,
When assembling a split mold, the breathable synthetic paper can sometimes be fixed to the mold surface, but if the breathable synthetic paper is not adhered to the mold surface, the breathable synthetic paper can be easily removed by removing the split mold. The breathable synthetic paper can be easily attached and removed.

In addition, in the case of foam molds in which the mold surface with vent holes becomes a part of the protrusion due to the hollow space, and the protrusion mold surface is removable, the edge of the breathable synthetic paper Note: Since the breathable synthetic paper is sandwiched as described above and a portion of the breathable synthetic paper is also pinched by the protruding mold surface, the breathable synthetic paper adheres closely to the mold surface and does not lift up from the mold surface. As a result, problems such as narrowing of the cavity of the foaming mold due to the breathable synthetic paper floating from the mold surface do not occur.

(Example) Examples of the present invention will be described below.

FIG. 1 is a sectional view showing when the foaming mold 10 according to an embodiment of the present invention is assembled, and FIG. 2 is a sectional view showing the foaming mold 10 after being assembled.
FIG.

The foaming mold 10 consists of a mold main body divided into two parts, a lower mold 12 and an upper mold 14, and a breathable synthetic paper 15, and has a double-use sheet-shaped cavity 16 inside the mold main body.

The cavity surface 18 of the lower mold 12 defines the seating surface of the seat, and the cavity surface 20 of the upper mold 14 defines the back surface of the seat. The upper mold 14 has a divided structure and is divided into three divided molds 14a, 14b, and 14c, and the divided surface 13a of each divided mold 14a, 14b, and 14c is
, 13b.

13c is bent toward the outside of the mold so that they can be stacked on top of each other, and can be connected by bolts 22 and nuts 24. 25 is a bolt insertion hole. Furthermore, a vent hole 26 is formed in the mold surface of the split mold 14b at the center of the upper mold for gas escape, which communicates between the inside and outside of the mold. The size (inner diameter), number, and position of the vent holes 26 are appropriately set depending on the shape of the product (foam). A vent hole is provided in the split mold 14b. The vent hole 2
6 is closed with a breathable synthetic paper 15 shown below.

The breathable synthetic paper 15 is mainly made of polyethylene and polypropylene fibers, and conforms to JTS P8117.
The air permeability was measured based on the paper and paperboard air permeability test method, i.e., paper with an area of 64,582
The average number of seconds it takes for +ml to pass is between 10 and 80. To obtain this air permeability, the thickness is 1.0 to 2.5.
The above fibers with a denier and length of 10 to 30 M are made into paper together with a binder, and this paper is compressed and crimped with a hot roll to a thickness of 0.1 to 0.25 mm and a density of 0.4 to 0.89.
/cm' or synthetic paper made by pressing 2 to 5 sheets of synthetic paper with a hot roll. This breathable synthetic paper 15 is assembled into the upper mold 14 when the divided mold 14b including the hole 26 and the remaining divided molds 14a and 14c are connected with bolts 22 and nuts 24. Divided surface (13a
and 13b, 13b and 13C), and the edges 15a, 15a are sandwiched between them to close the vent hole 26 on the mold surface of the split mold 14b.

FIG. 3 is a cross-sectional view showing the assembly of a foaming mold 28 according to another embodiment, and FIG. 4 is a cross-sectional view showing the assembly of the foaming mold 28 according to another embodiment.

The foam mold 28 is a so-called hollow mold, and is composed of a mold main body consisting of a lower mold 30 and an upper mold 32, and a breathable synthetic paper 34. The lower mold 30 has a cavity 36 shaped like a product.
is formed. The upper mold 32 is divided into three parts fi32a
, 32b, and 32c, and a vent hole 38 and a hole 39 for attaching the protrusion 40 are formed in the central split mold 32b. The protrusion 40 is for thinning, and is removably housed in the inner surface of the split mold 32b by a bolt 42 and a nut 44 buried at one end, and its surface becomes a part of the mold surface.

When assembling the upper mold, the breathable synthetic paper 34 is divided into a divided mold 32b including a vent hole 38 and a remaining divided mold 32a.

The edge 34a is sandwiched between the protrusions 40 and the mold surface of the split mold 32b, and the center portion is sandwiched between the protrusion 40 and the mold surface of the split mold 32b to close the vent hole 38.

Note that the foaming mold of the present invention is not limited to one that is divided into upper and lower halves, but may be one that is divided into three parts as shown in FIG. 5, or one that is divided into more parts.

FIG. 5 is a sectional view of a foam mold 46 consisting of three parts.6 The foam mold 46 has a lower mold 4 that defines the back surface of the seat back.
8, a mold body consisting of an upper mold 50 defining the back surface of the seat back, and breathable synthetic paper 52. Upper mold 50
is divided into a central portion 54 and both edge portions 56, and the central portion 54 further includes a divided mold 54b including a vent hole 58,
It is composed of the gJ molds 54a and 54c on both sides, a divided mold 54b including the vent hole 58, and the remaining divided mold 5.
Breathable synthetic paper 5 with both edges sandwiched between 4a and 54c
2, the vent hole 58 is closed 1.

In order to mold a polyurethane foam using a foam mold formed in this way, the mold is first assembled by sandwiching and fixing breathable synthetic paper between the split mold containing the vent hole and the remaining split mold. ! - After tacking, the polyurethane raw material is injected into the mold cavity and foamed. The gas escaping from the foam and the air remaining in the mold escape through the breathable synthetic paper and out of the mold through the vent holes. On the other hand, the polyurethane raw material is blocked by the breathable synthetic paper and foams within the mold cavity without entering the vent hole.5Then, by removing the foam from the mold after a predetermined period of time, the desired foam can be obtained.

Thereafter, the polyurethane raw material is injected into the cavity while the breathable synthetic paper is clamped and fixed, and the molding of the foam is repeated.

In addition, when molding this foam, a mold release agent is usually applied to the roughened cavity surface and one side of the breathable synthetic paper. Since a mold release agent originally has a high surface tension, even if the air-permeable synthetic paper is made of polyolefin-based plastic fibers that do not easily break apart on the surface, air permeability will be slightly inhibited.

Therefore, depending on the release agent used, it is preferable to select a breathable synthetic paper based on experiments so that it has the desired breathability.

When it is time to replace the breathable synthetic paper after repeating the molding of the foam for a certain period of time, the split molds that sandwich the breathable synthetic paper are uncoupled and the breathable synthetic paper is removed. ,
A new breathable synthetic paper is again sandwiched between the split mold in which the vent hole is formed and the remaining split mold and attached to the mold surface.

(Effects) As described above, the present invention is to sandwich the edge of breathable synthetic paper between the first divided mold including the vent hole and the remaining divided mold and attach it to the mold surface, thereby closing the vent hole. Since double-sided adhesive tape is not used, installation of the breathable synthetic paper,
Replacement can be done easily. In addition, even if there is a protrusion for filling the mold on the mold surface including the vent hole, the protrusion is removable and a part of the breathable synthetic paper is sandwiched between the protrusion mold surface. Synthetic paper does not lift up from the mold surface, and a good foam can be formed.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the assembly of a foaming mold according to one embodiment of the present invention, Fig. 2 is a sectional view of the foaming mold after its assembly, and Fig. 3 is a sectional view showing the assembly of the foaming mold according to another embodiment. The foam mold is assembled in a sectional view showing the time, and Figure 4 is a sectional view of the foam mold after its assembly.
FIG. 5 is a sectional view of a foam mold according to still another embodiment. 12, 30.48: Lower mold, 14.32.50: Upper mold, 1
4a, : 32a, 54a, 14c, 32c, 54c:
Divided type, 14b, 32b, 54b: Divided type including vent holes, 15, 34.52: Breathable synthetic paper,
40: Protrusion, 26 38, 58 Covent Hall

Claims (2)

[Claims] (1) In a foam mold with a split mold with a vent hole closed with breathable synthetic paper, the mold containing the vent hole has a split structure, and the edge of the breathable synthetic paper that closes the vent hole is vented. A foam mold characterized by being sandwiched and fixed between a split mold including a hole and a remaining split mold. (2) A part of the mold surface of the split mold including the vent hole is a removable protrusion, and a part of the breathable synthetic paper is sandwiched between the removable protrusion mold surface. The foaming mold according to item 1.