Molding die and method for producing foam molding product

Abstract

The present invention provides a molding die which prevents unnecessary flow of a foaming raw material into an insert material, which is integrally molded with a foam molded product, and contributes to the production of a sound foam molded product.　On the bottom surface of a mold that defines a cavity of the molding die, a projection part and a vertical wall extending beyond the top part of the projection part along the projection direction of the projection part are formed.

Description

Mold and method for manufacturing foam-molded products

[0001] The present invention relates to a molding die used to manufacture a foam-molded product, particularly a foam-molded product into which an insert material is integrally molded, and a method for manufacturing a foam-molded product using this molding die.

[0002] In the case of vehicle seats such as automobiles, and seats for household use such as floor chairs and sofas, foam molded articles (urethane foam) are sometimes integrally molded with insert materials during foam molding. Examples of such insert materials include backing materials for foam molded articles and fasteners for the skin material that covers the surface of foam molded articles.

[0003] For example, Patent Document 1 discloses a foam molding die used to integrally mold a backing material such as a nonwoven fabric as an insert material into a seat pad for a seat. As described in Patent Document 1, the backing material is attached to the molding die by magnetic force in order to integrally mold the backing material at a predetermined position of the foam molded product.

[0004] Furthermore, the fasteners for the skin material described above are used to secure the skin material covering the foam molded product to the foam molded product, and a typical example is a hook-and-loop fastener. The hook-and-loop fastener must be firmly and stably embedded in the foam molded product when the foam molded product is foam molded. Therefore, even when the hook-and-loop fastener is placed inside the foam molding mold, it is often attached to the molding mold using magnetic force.

[0005] Japanese Patent Application Laid-Open No. 2013-233719

[0006] An example of a molding die to which the above-mentioned hook-and-loop fasteners can be attached is shown in Figure 1. That is, as shown in Figure 1, a cross section of the lower mold 1 of a foam molding die consisting of an upper mold and a lower mold is schematically shown. A convex portion 3 is formed on the mold bottom surface 2 that defines the cavity 10 of the molding die, and the foam molding is performed with a hook-and-loop fastener 4 attached to the top 30 of this convex portion 3. As shown in Figure 2, a top view of region II in Figure 1, the convex portion 3 is a protruding strip extending along the mold bottom surface 2 in accordance with the length and shape corresponding to the long hook-and-loop fastener 4 to be attached, and magnets 31 are embedded continuously or intermittently in the longitudinal direction inside. Meanwhile, as shown in Figure 2, a magnetic body 40 is attached to the hook-and-loop fastener 4, so that it is attracted to or fixed to the top 30 of the convex portion 3 via magnetic force.

[0007] 3, foam molding is performed by supplying foaming raw material 6 from a supply head 5 into the cavity 10 of the open lower mold 1, and then closing the upper mold (not shown) to foam the foaming raw material 6. Here, the foaming raw material 6 is typically supplied to a plurality of predetermined positions in the cavity 10 by moving the supply head 5. Because the foaming raw material 6 is a low-viscosity liquid, strong flow may occur at the mold bottom surface 2 depending on the amount and speed of supply.

[0008] In particular, the foaming raw material 6 supplied to the inclined portion 20 of the mold bottom surface 2 flows down the slope, resulting in a faster flow rate than, for example, the flat portion in the center. This causes the foaming raw material 6 to strongly collide with the convex portions 3 and the hook-and-loop fasteners 4. As shown by the arrows in Figure 4, this impinging flow of foaming raw material 6 lifts the hook-and-loop fasteners 4 attached to the convex portions 3 from their top portions 30, causing them to partially curl up. As a result, the foaming raw material 6 penetrates through the gaps in the curled-up portions of the hook-and-loop fasteners 4, and after foam molding, the surface of the hook-and-loop fasteners 4 facing the top portions 30 is covered with urethane foam. Because the surface of the hook-and-loop fasteners 4 facing the top portions 30 is the fastening surface of the hook-and-loop fasteners, the urethane foam impairs their fastening function, resulting in the production of defective products. This results in wasted material, which is undesirable from an environmental perspective.

[0009] Therefore, an object of the present invention is to provide a molding die that solves the above-mentioned problems when supplying foaming raw material, thereby preventing the foaming raw material from unnecessarily flowing into the insert material that is molded integrally with the foam-molded product, and thereby contributing to the production of sound foam-molded products. Another object of the present invention is to propose an advantageous method for producing a foam-molded product with an insert material.

[0010] The present inventors have conducted extensive research into ways to solve the above problems, and have found that an effective solution is to prevent the leading edge of the foaming raw material from colliding with the boundary between the convex portion on the bottom surface of the mold and the insert material on the convex portion when the foaming raw material is supplied into the mold cavity.

[0011] 1. A molding die having a bottom surface that defines a cavity of the molding die, the bottom surface having a convex portion and a vertical wall that extends beyond the top of the convex portion along the protruding direction of the convex portion.

[0012] 2. A molding die used to manufacture a foam-molded product with an insert material, the molding die having, on the bottom surface of the mold that defines the cavity of the molding die, a convex portion having an apex that serves as a mounting portion for the insert material, and a vertical wall that extends beyond the apex in the protruding direction of the convex portion by at least the thickness of the insert material.

[0013] 3. The molding die according to 1 or 2, wherein the vertical wall extends from a position adjacent to at least a part of the side surface forming the protrusion along the protrusion direction of the protrusion.

[0014] 4. The molding die according to any one of 1 to 3, wherein the vertical wall extends from the top of the convex portion along the protruding direction of the convex portion.

[0015] 5. The molding die according to any one of 1 to 4 above, wherein the vertical wall is provided on a convex portion disposed on an inclined portion of the bottom surface of the die.

[0016] 6. The molding die according to any one of 1 to 5 above, wherein the convex portion is a convex streak extending along the bottom surface of the die.

[0017] 7. The molding die according to 6 above, wherein the vertical wall extends continuously or intermittently in the longitudinal direction of the protrusion.

[0018] 8. The molding die according to any one of 1 to 7 above, wherein the vertical wall is adjacent to a side surface that is in a direction intersecting the flow direction of the foaming raw material injected into the cavity, among the side surfaces that form the protrusion.

[0019] 9. The molding die according to any one of 1 to 8 above, wherein the insert material is a hook-and-loop fastener.

[0020] 10. A method for manufacturing a foam-molded product in which an insert material is integrally molded, comprising: attaching the insert material to the top of a convex portion provided on the bottom surface of the mold that defines a cavity of the molding mold; and then, when foaming raw material for the foam-molded product is supplied into the cavity, a vertical wall extending beyond the top of the convex portion in the protruding direction of the convex portion prevents the foaming raw material from colliding with the top and the insert material at least at the inclined portion of the bottom surface of the mold, thereby performing foam molding.

[0021] According to the molding die of the present invention, when the foaming raw material is supplied into the mold cavity, the vertical wall prevents the leading edge of the raw material from colliding with, for example, the insert material, thereby preventing the foaming raw material from undesirably flowing into the insert material and enabling the production of sound foam-molded products. Furthermore, according to the manufacturing method of the present invention, the adhesion of unnecessary urethane foam to the insert material is prevented, thereby realizing production with a low reject rate.

[0022] 5 is a cross-sectional view of the lower mold of a molding die. FIG. 6 is a top view showing region II of FIG. 1. FIG. 7 is an explanatory view showing how the foaming raw material is supplied to the mold bottom surface of the lower mold. FIG. 8 is an explanatory view showing the collision of a foaming raw material flow with a convex portion on the mold bottom surface. FIG. 9 is a partial cross-sectional view of the lower mold showing a vertical wall to be provided on the convex portion on the mold bottom surface. FIG. 10 is a top view of the convex portion shown in FIG. 5. FIG. 6 is a partial cross-sectional view of the lower mold showing a vertical wall to be provided on the convex portion on the mold bottom surface. FIG. 7 is a partial cross-sectional view of the lower mold showing another form of a vertical wall to be provided on the convex portion on the mold bottom surface. FIG. 8 is a photograph of the locking functional surface side of a hook-and-loop fastener in a foam-molded product.

[0023] [Molding die] One embodiment of the molding die of the present invention will be described in detail below with reference to Figures 5 and 6. Figures 5 and 6 show a portion corresponding to region II of the molding die 1 shown in Figure 1, and the same components as those of the molding die 1 shown in Figure 1 are given the same reference numerals and will not be described again. Furthermore, a hook-and-loop fastener will be used as a typical example of the insert material.

[0024] The molding die 1 shown in Fig. 5 has a vertical wall 7 extending from a position adjacent to at least a part of the side surface forming the protrusion 3, along the protrusion direction of the protrusion 3, beyond the top 30 of the protrusion 3. In the illustrated example, the protrusion 3 is a long, rectangular parallelepiped protrusion that curves midway, as shown in the top view of Fig. 6, and has the vertical wall 7 on at least the side surface 3a that faces the supply portion of the foaming raw material 6 (see Fig. 3) among the side surfaces forming the protrusion 3. In other words, the vertical wall 7 is provided along the protrusion direction of the protrusion 3 in contact with the side surface 3a that the flow of the foaming raw material 6 first reaches among the side surfaces forming the protrusion 3.

[0025] Here, "along the protruding direction of the convex portion 3" means that it is sufficient to be roughly oriented in the protruding direction, and does not necessarily mean that it is on the contour line of the side surface 3a. The key is that it is sufficient to be oriented in a direction that can prevent the foaming raw material 6 from colliding with the hook-and-loop fastener 4. Therefore, it may be inclined with respect to the contour line of the side surface 3a, for example, vertically. From the viewpoint of the manufacturing efficiency of the foam-molded product, it is preferable that it be in the direction in which the foam-molded product is pulled out. Therefore, the vertical wall 7 does not necessarily need to be in contact with the side surface 3a, and there may be a gap between the vertical wall 7 and the side surface 3a depending on the direction in which the vertical wall 7 extends, etc.

[0026] In addition, if the flow of the foaming raw material 6 collides with other side surfaces forming the protrusions 3, the vertical walls 7 may be similarly provided on those side surfaces. For example, in the illustrated example, if the flow of the foaming raw material 6 collides with side surfaces located at both ends in the longitudinal direction of the protrusions 3, it goes without saying that the vertical walls 7 may be provided on those side surfaces.

[0027] Here, it is essential that the vertical wall 7 extends beyond the top 30 of the projection 3, specifically that it extends beyond the top 30 by at least the thickness of the hook-and-loop fastener 4. In other words, at least the boundary between the top 30 of the projection 3 and the hook-and-loop fastener 4 must be covered by the vertical wall 7. This reliably prevents the hook-and-loop fastener 4 from peeling off from the top 30 due to the impinging flow of the foaming raw material 6. More specifically, the vertical distance t (see FIG. 5 ) from the top 30 of the projection 3 to the tip of the vertical wall 7 is preferably equal to or greater than the thickness of the hook-and-loop fastener 4, and more preferably greater than the thickness of the hook-and-loop fastener 4.

[0028] 6, the vertical wall 7 is provided continuously over the entire length of the projection 3 in the longitudinal direction, but may be provided discontinuously with a small gap therebetween. Alternatively, depending on the shape of the projection 3, the vertical wall 7 may be provided only on the side surface portion where the foaming raw material 6 first reaches.

[0029] In the molding die shown in Fig. 5, a vertical wall 7 is provided on the convex portion 3 of the inclined portion of the mold bottom surface 2, where the flow of the foaming raw material 6 is likely to be fast. Note that Fig. 5 is a partial enlarged view of region II, and as shown in Fig. 3, there is also an inclined portion on the side of the mold bottom surface 2 of the molding die 1 opposite to region II across the central compartment. The foaming raw material 6 is also supplied to this inclined portion. Therefore, for the convex portion 3 of this inclined portion, a vertical wall 7 must also be provided on the side surface 3b on the central compartment side, as shown in Fig. 7.

[0030] Incidentally, when the inclination angle of the inclined portion of the mold bottom surface 2 relative to the horizontal plane is 10° or more, the flow of the foaming raw material 6 becomes strong and the curling of the hook-and-loop fastener 4 becomes noticeable, so it is particularly advantageous to provide a vertical wall 7 on the convex portion 3 of such an inclined portion.

[0031] 3, when the central section in the mold bottom surface 2 to which the foaming raw material 6 is supplied is flat, the flow of the foaming raw material 6 is gentle, and therefore it is not necessary to provide the vertical wall 7 on the protrusions 3 arranged in the central section. However, when there is a concern that partial detachment of the hook-and-loop fastener 4 may occur due to the collision of the foaming raw material 6, for example, when the supply speed of the foaming raw material 6 in the central section is extremely fast, it is preferable to also provide the vertical wall 7 on the side of the protrusions 3 arranged in the central section that the foaming raw material 6 collides with.

[0032] In addition, in the example shown in Figure 5, the vertical wall 7 extends in the protruding direction from the side surface 3a of the convex portion 3, but it may also be configured as shown in Figure 8, for example, in which the vertical wall 7 is placed on the surface of the top portion 30 of the convex portion 3, and the vertical wall 7 extends in the protruding direction from the surface of the top portion 30.

[0033] [Method for manufacturing foam-molded product] Foam molding can be performed using the above-described molding die 1. That is, after attaching a hook-and-loop fastener 4 to the top 30 of a protrusion 3 provided on the bottom surface 2 of the die, foam molding is performed by supplying the foaming raw material 6 of the foam-molded product toward the bottom surface 2 of the die. As described above, when the foaming raw material 6 is supplied into the die, the vertical wall 7 arranged adjacent to a predetermined side surface of the protrusion 3 prevents the foaming raw material 6 from coming into contact with the top 30 and the hook-and-loop fastener 4, thereby preventing the urethane foam from seeping out onto the engaging surface side of the hook-and-loop fastener 4.

[0034] Using the molding die 1 shown in Figures 5 and 6, a 2 mm thick hook-and-loop fastener 4 was attached to the top 30 of the protrusion 3 via magnetic force. Next, the foaming raw material 6 was supplied to the bottom surface 2 of the die as shown in Figure 2, and the upper die was closed. Thereafter, foam molding was carried out under a predetermined pressure to produce an automobile seat material.

[0035] A vertical wall 7 was provided on the side surface 3 a of the protrusion 3 formed on the inclined portion 20 (inclination angle relative to the horizontal plane: 10°) of the mold bottom surface 2. The vertical wall 7 had a height t of 2 mm extending from the top 30 of the protrusion 3, and furthermore, the vertical wall 7 was installed over the entire longitudinal length of the side surface 3 a of the protrusion 3, as shown in FIG.

[0036] For comparison, foam molding was carried out under the same conditions using a molding die having the same configuration except that the vertical wall 7 was not provided.

[0037] In the seat material thus produced, the finished state of the hook-and-loop fastener 4 attached to the convex portion 3 of the inclined portion 20 of the mold bottom surface 2 was visually confirmed. Figure 9 shows a photograph of the locking surface of the hook-and-loop fastener 4 exposed on the surface of the seat material after molding. As shown in Figure 9, in the case where there was no vertical wall, urethane foam was attached (indistinct portions) to the locking elements (hook portions) of the locking surface of the hook-and-loop fastener 4. In contrast, in the case where there was a vertical wall, there was no urethane foam attached to the locking surface of the hook-and-loop fastener 4, and the locking elements (hook portions) of the locking surface could be clearly confirmed.

[0038] DESCRIPTION OF SYMBOLS 1 Lower mold 2 Mold bottom surface 3 Convex portion 3a Side surface 3b Side surface 4 Hook-and-loop fastener 5 Supply head 6 Foaming material 7 Vertical wall 10 Cavity 20 Inclined portion 30 Top portion 31 Magnet 40 Magnetic material

Claims

1. A molding die having a convex portion on the bottom surface of the die that defines a cavity of the molding die, and a vertical wall that extends beyond the top of the convex portion along the protruding direction of the convex portion.

2. A molding die used to manufacture foam-molded products with insert material, the molding die having, on the bottom surface of the mold that defines the cavity of the molding die, a convex portion having an apex that serves as an attachment portion for the insert material, and a vertical wall that extends beyond the apex in the protruding direction of the convex portion by at least the thickness of the insert material.

3. A molding die according to claim 1 or 2, wherein the vertical wall extends from a position adjacent to at least a part of the side surface forming the convex portion along the protruding direction of the convex portion.

4. A molding die according to any one of claims 1 to 3, wherein the vertical wall extends from the top of the convex portion along the protruding direction of the convex portion.

5. A molding die according to any one of claims 1 to 4, wherein the vertical wall is provided on a convex portion arranged on an inclined portion of the bottom surface of the die.

6. A molding die according to any one of claims 1 to 5, wherein the convex portion is a convex ridge extending along the bottom surface of the die.

7. The molding die according to claim 6, wherein the vertical wall extends continuously or intermittently in the longitudinal direction of the ridge.

8. A molding die according to any one of claims 1 to 7, wherein the vertical wall is adjacent to one of the side surfaces forming the convex portion that is oriented in a direction that crosses the flow direction of the foaming raw material injected into the cavity.

9. The molding die according to claim 2, wherein the insert material is a hook-and-loop fastener.

10. A method for manufacturing a foam-molded product in which an insert material is integrally molded, comprising the steps of: attaching the insert material to the top of a convex portion provided on the bottom surface of the mold that defines the cavity of the molding mold; and then, when supplying foaming raw material for the foam-molded product into the cavity, using a vertical wall that extends beyond the top of the convex portion in the protruding direction of the convex portion to prevent the foaming raw material from colliding with the top and the insert material at least at the inclined portion of the bottom surface of the mold to perform foam molding.

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