JP4998178B2 - Mold for foam molding - Google Patents

Description

  The present invention relates to a mold for foam molding provided with a strip-shaped recess for escape of foam gas.

As this type of foam molding die, the foam molding die described in Citation 1 is known. This mold for foam molding is provided with a strip-shaped recess (also called a vent vent) for releasing foam gas on the closing surface of the upper die or the lower die, and in the circumferential direction of the closing surfaces of the upper die and the lower die. Similarly, circumferential recesses for releasing the foaming gas are provided over the entire circumference.
And according to the above-mentioned known technology, by removing the foaming gas generated in the cavity at the time of foam molding with both the gas vent and the circumferential recess, it is possible to prevent problems of the molded product due to foam gas venting failure. be able to.
JP 2005-153293 A

By the way, in this type of foam molding die, for example, if a gas vent is provided (even if a circumferential recess is not provided), it is possible to prevent a foam gas vent failure by adjusting molding conditions and the like. . However, in the known technique, a plurality of burrs (a burr made of a foaming material that has entered the circumferential recess) and a mushroom-like burr made of a foaming material that has entered a large amount into the degassing vent under any molding conditions. (So-called beards)) always occur, and the work to remove them is troublesome.
The present invention was devised in view of the above points, and the problem to be solved by the present invention is to form a molded product by bringing the closing surfaces of the upper mold and the lower mold into close contact so that the foaming raw material does not enter. This is to satisfactorily prevent excessive burr formation.

As means for solving the above-mentioned problems, the foam molding die of the first invention comprises an upper mold and a lower mold that form a cavity by closing, and the foaming gas generated from the foaming raw material in the cavity is It is the structure discharged | emitted outside by the strip-shaped recessed part for foaming gas escape provided in the closing surface of a type | mold or a lower type | mold.
The foam molding mold forms the cavity in a sealed state while maintaining the external communication state of the strip-shaped recess by the seal member provided in the circumferential direction of the closing surface of the upper mold or the lower mold. The seal member has an extending side portion that extends into the cavity. For this reason, when the upper die and the lower die are closed, the extending side portion of the seal member extends into the cavity (in a protruding shape). Therefore, Kukunaru the resulting gap (recess) of the portion mating closing of the upper mold and the lower mold cavity side.
Further, a restricting portion is provided on the extending side portion protruding into the cavity, and the flow of the foaming raw material in the cavity can be restricted so that the foaming raw material does not enter the closed portion of the upper die and the lower die.

Further, in the foam molding die of the first invention , the strip-shaped concave portion has an opening width and an opening depth that are suddenly narrower than the opening on the cavity side (not a step but a step or a protrusion). E) It has a narrow part. For this reason, according to the strip-shaped recessed part, it can reduce or prevent that a foaming raw material approachs from a cavity in a narrow part.

According to a second aspect of the present invention, there is provided a foam molding die according to the first invention, wherein the sealing member includes a base layer bonded and fixed to at least one closing surface of the upper die and the lower die. And an adhesion layer that overlaps the base layer and faces the other closing surface different from the one. And a base layer is a resin layer containing an aluminum type additive, and is equipped with the physical property (for example, the outstanding adhesiveness and workability) derived from an aluminum type additive. On the other hand, the adhesion layer is a rubber layer that does not contain an aluminum-based additive and is softer than the base layer (for example, a rubber layer having a Shore hardness of 75 or more and less than 85 without containing an aluminum-based additive). is there). When the upper mold and the lower mold are closed , the flexible adhesive layer brings the upper mold and the lower mold into close contact with each other, so that the cavity is more reliably formed in a sealed state.

According to the foam molding die of the first invention, it is possible to satisfactorily prevent the formation of excess burrs in the molded product by bringing the closing surfaces of the upper mold and the lower mold into close contact so that the foaming raw material does not enter. . In addition, according to the foam molding die of the first invention, it is possible to better prevent the formation of excessive burrs in the molded product. And according to the metal mold | die for foam molding of 2nd invention, the adhesiveness of an upper mold | type and a lower mold | type can be improved more.

The best mode for carrying out the present invention will be described below with reference to FIGS.
[overall structure]
The foam molding die 2 of the present embodiment is provided with an upper die 4 and a lower die 6 with reference to FIG. 1 and FIG. 2, and by closing these together, a cavity 8 is formed inside the foam molding die 2. Form. A foam raw material (for example, urethane foam) is poured into the cavity 8.
The foam molding die 2 is formed by a sealing member 10 provided in the circumferential direction of the closing surface 6a of the lower die 6 and a later-described atypical vent vent 30 for releasing the foaming gas (a strip-shaped recess having an internal shape different from that of the conventional one). ), The cavity 8 is formed in a sealed state while maintaining the external communication state.
The foaming gas generated from the foaming raw material inside the cavity 8 at the time of foam molding is discharged to the outside of the foam molding die 2 by the modified gas venting vent 30 provided on the closing surface 6 a of the lower mold 6.

  Specifically, in the present embodiment, the sealing member 10 (details will be described later) is provided on the entire circumference of the closing surface 6a of the lower mold 6 in the present embodiment with reference to FIG. A plurality of irregular vent vents 30 (internal shape will be described later) and discharge chambers 50 are alternately provided in the seal member 10. Specifically, referring to FIG. 3 and FIG. 4, the irregular vent vent 30 is formed by cutting the surface of the seal member 10 into a strip-like shape. On the other hand, the discharge chamber 50 is formed so as to penetrate the seal member 10 in a substantially rectangular shape when viewed from the front in the thickness direction. The modified vent hole 30 communicates with two adjacent discharge chambers 50 and 50 through communication grooves 42 and 42 as its constituent elements. Each discharge chamber 50 is provided with a discharge hole 52 communicating with the outside.

  Then, referring to FIG. 4, the closing surface 4a of the upper die 4 is brought into contact (close contact) with the seal member 10 of the lower die 6, and the upper die 4 and the lower die 6 are closed to make the cavity 8 hermetically sealed. Form. At this time, since the irregular vent hole 30 (and the communication groove 42 as a component thereof) and the discharge chamber 50 are both concave with respect to the surface of the seal member 10 (see FIG. 5), they are crushed by the upper mold 4. The internal shape is maintained as it is. For this reason, the foaming gas that has entered from the opening 32 of the odd-shaped gas venting vent 30 passes through the communication groove 42 of the odd-shaped gas venting vent 30 and is discharged to the outside from the discharge hole 52 of the discharge chamber 50 (the external communication state is maintained). Will be). Hereinafter, main components will be described in detail.

[Seal member]
In the sealing member 10 of this embodiment, referring to FIG. 5, the side portion on the cavity 8 side is an extended side portion 20 that extends into the cavity 8. When the upper mold 4 and the lower mold 6 are closed and the cavity 8 is sealed, the extending side portion 20 extends from the closed portion 16 of the upper mold 4 and the lower mold 6 into the cavity 8 (in a protruding shape). Is done. For this reason, a gap (for example, a recess corresponding to a circumferential recess of a known technique) is not generated as much as possible in the closing portion 16 on the cavity 8 side.
And the upper side edge (edge which faces the upper mold | type 4) of the extension side part 20 is provided with the triangular-shaped control part 18 by the longitudinal cross-sectional view. The restricting portion 18 protrudes in the thickness direction of the seal member 10 and is disposed so as to cover the lower side (lower die 6 side) of the closing portion 16 of the upper die 4 and the lower die 6. The triangular regulating portion 18 is formed in an edge shape such that the tip thereof is directed toward the inside of the cavity 8. With such a configuration, referring to the arrow line S in FIG. 5, the foaming raw material in the cavity 8 (the upward flow of the foaming raw material generated during heat molding) is closed from the lower side (lower mold 6 side). Even if it tries to go to the mating point 16, it is blocked by the restricting portion 18 of the extending side portion 20. The foaming raw material is guided toward the inner side of the cavity 8 along the regulating portion 18 that is directed toward the inside of the cavity 8.
As described above, according to the seal member 10 (the extending side portion 20 and the restricting portion 18) of the present embodiment, the upper mold 4 and the lower mold 6 are satisfactorily adhered, and the foaming raw material in the cavity 8 is It is possible to prevent or reduce entry into the closing portion 16 of the lower mold 6. For this reason, it is possible to satisfactorily prevent the formation of excessive burrs on the molded product (particle line).

  By the way, when the upper die 4 and the lower die 6 are closed, the restricting portion 18 protrudes in the thickness direction of the seal member 10 so as to cover the closing portion 16 (part or all) on the cavity 8 side. It only has to be. For this reason, the shape of the restricting portion 18 is not limited to the triangular shape in the longitudinal section shown in the figure, but may be various shapes such as a polygonal shape such as a rectangular shape or a pentagonal shape in the longitudinal sectional view, a hemispherical shape or a semi-elliptical spherical shape in the longitudinal sectional view. Can do. The regulating portion 18 has an edge shape (the tip is sharp in a longitudinal section, for example, a trapezoidal shape, a pentagon shape, a tip R-attached trapezoid shape, a tip R-attached triangle shape, a tip R-attached pentagon shape). The shape of the foamed raw material in the cavity 8 is more preferable because the foamed raw material is guided to the inside of the cavity 8 well.

The sealing member 10 of this embodiment includes a base layer 14 that is bonded and fixed to the closing surface 6a of the lower mold 6 (one), and an upper mold 4 (the other different from the other) that overlaps the base layer 14. And an adhesion layer 12 facing the surface 4a.
The base layer 14 is a resin layer containing an aluminum-based additive and has physical properties derived from the aluminum-based additive (for example, excellent adhesiveness and workability). On the other hand, the adhesion layer 12 is a rubber layer that does not contain an aluminum-based additive and is more flexible than the base layer 14. Since the sealing member 10 has a two-layer structure as described above, the upper die 4 is adhered to the lower die 6 satisfactorily by the base layer 14 of the sealing member 10 and the flexibility of the adhesion layer 12 facing the mating surface of the upper die 4. And the lower mold 6 can be in close contact with each other to improve the sealing performance of the cavity 8.

  The resin constituting the base layer 14 is, for example, a thermosetting resin such as an epoxy resin, a phenol resin, a melamine resin, a urea resin, an unsaturated polyester resin, an alkyd resin, a polyurethane resin, or a thermosetting polyimide resin. The base layer 14 is obtained by adding an aluminum-based additive (for example, powder (aluminum powder) such as aluminum or alumina) to these resins (one kind or a mixture of plural kinds), and then curing by appropriately adding a curing agent. be able to.

  On the other hand, the rubber constituting the adhesion layer 12 is, for example, urethane rubber, butadiene rubber, natural rubber, nitrile rubber, chloroprene rubber, butyl rubber, styrene rubber, ethylene propylene rubber, silicon rubber, or fluorine rubber. An adhesion layer obtained by adding a curing agent to these rubbers (one kind or a mixture of plural kinds) as appropriate (without containing an aluminum-based additive) and having a Shore hardness (test method: JIS Z2246) of 75 or more and less than 85 Twelve. It is preferable that the adhesion layer 12 is made of a semi-curing rubber having a Shore hardness of around 80 (77 to 83), which is excellent in flexibility, than the adhesion layer 12 made of a curable rubber (solid rubber) having a Shore hardness of around 85.

Here, the manufacturing method of the sealing member 10 of a present Example is illustrated.
An aluminum powder-containing epoxy resin (typically putty) before curing is applied to the mating surface 4a of the upper mold 4 so as to have a predetermined thickness (preferably a thickness corresponding to the gap dimension between the upper mold 4 and the lower mold 6). Mold. At this time, a rectangular form may be embedded in a portion corresponding to the discharge chamber 50 described above. Then, the epoxy resin layer molded by the upper mold 4 is replaced (transferred) to the lower mold 6.
Then, after the epoxy resin layer is scraped from the epoxy resin layer transferred to the lower mold 6 (preferably so that its thickness is about half), urethane rubber (typically putty-like) before curing is formed on the epoxy resin layer surface. ) Is applied by the thickness of the shaved epoxy resin. At this time, since the epoxy resin layer (base layer 14) contains aluminum powder, it is easy to cut. Then, the epoxy resin layer and the urethane rubber layer are cured by applying heat, and the “base layer 14” composed of an epoxy resin containing aluminum powder and the “adhesion layer 12” composed of urethane rubber that is more flexible than the base layer 14. The sealing member 10 consisting of is manufactured. Then, the surface of the cured seal member 10 is cut into a strip shape to form the atypical vent vent 30.
In addition, as the base layer 14, an epoxy resin containing aluminum powder (manufactured by ITW Industry) can be suitably used. As the adhesion layer 12, a two-component urethane rubber (a urethane rubber not containing aluminum powder and adjusted to a Shore hardness of 80, manufactured by ITW Industry Co., Ltd.) can be suitably used.

[Atypical venting vent]
With reference to FIGS. 3 and 4, the odd-shaped vent vent 30 of this embodiment includes an opening 32 that opens toward the cavity 8, a wall (blocking wall 44) that faces the opening 32, and a blocking wall 44. And a communication groove 42 communicating with the discharge chamber 50.
The odd-shaped venting vent 30 includes a narrow portion (projecting portion 36, stepped portion 46) between the opening portion 32 and the communication groove 42 where the opening width and opening depth suddenly narrow with respect to the opening portion 32. .
In the present embodiment, referring to FIG. 3, a pair of projecting portions 36 and 36 (triangular shape in front view) projecting from both side surfaces 39 and 39 of the odd-shaped venting vent 30 are provided, and the opening width W1 of the opening 32 is provided. On the other hand, the opening width W2 of the narrow portion is abruptly narrowed. By the projecting portions 36, 36, the flow of the foaming raw material M that has entered the irregular venting vent 30 can be changed (the momentum of the flow of the foaming raw material M is stopped). Furthermore, the projecting portion 36 includes a first rising surface 38 that rises at an angle θ1 (preferably θ1 of 45 ° or more and less than 90 °) with respect to the side surface of the variant degassing vent 30. The flow of the foaming raw material M that has entered can be well blocked.

At this time, the atypical vent hole 30 is, for example, a protruding portion 36 having a first rising surface 38 that rises at an angle θ1 of 90 ° or more, like a protruding portion 36a having a square shape in front view shown in FIG. It is more preferable because the flow of the foaming raw material M can be better blocked.
By the way, the protruding portion 36 protrudes from both side surfaces 39, 39 of the modified gas venting vent 30 to change at least the flow of the foaming raw material M that has entered the modified gas venting vent 30 (stops the flow of the foaming raw material M). I can do it. For this reason, for example, as shown in FIG. 6 (b), the odd-shaped venting vent 30 can be provided with protruding portions of various shapes such as a protruding portion 36 b having a substantially semicircular shape when viewed from the front.

  Further, in this embodiment, referring to FIG. 4, a stepped portion 46 is provided between the opening side bottom surface 34 of the modified venting vent 30 and the blocking wall side bottom surface 40, and the opening depth of the opening side bottom surface 34 is determined. The opening depth D2 of the closed wall side bottom surface 40 is abruptly narrower than the length D1. According to the stepped portion 46 of the narrow portion, the flow of the foaming raw material M that has entered the irregular gas venting vent 30 can be changed (the momentum of the flow of the foaming raw material M is stopped). Further, the stepped portion 46 of this embodiment includes a second rising surface 48 that rises at a right angle (θ2 is 90 °) with respect to the opening-side bottom surface 34 of the modified gas venting vent 30. The flow of the foaming raw material M that has entered the inside 30 can be well blocked.

  By the way, the level | step-difference part 46 should just be the structure which can change the flow of the foaming raw material M which approached in the unusual shape gas venting vent 30 (stops the vigor of the flow of the foaming raw material M). That is, the step portion 46 may be configured to protrude in a step shape with respect to the opening side bottom surface 34 (preferably the rising angle θ2 of the second rising surface 48 is set to 45 ° or more). At this time, it is more preferable that the rising angle θ2 of the second rising surface 48 is 90 ° or more, since the flow of the foaming raw material M that has entered the irregular venting vent 30 is well blocked at the stepped portion 46.

Then , according to the modified gas venting vent 30 , referring to FIG. 4, the foaming gas (arrow line G) that has entered the modified gas venting vent 30 flows toward the communication groove 42 without staying in the narrow portion. However, the foaming material M that has entered following the foaming gas is stopped in the flow (or the flow is blocked) in the narrow portion (the protruding portion 36 and the stepped portion 46).
For this reason, according to the modified vent hole 30, it is possible to reduce or prevent excessive burr formation of the molded product by satisfactorily blocking the entry of the foaming raw material M by the narrow portion. Specifically, mushroom-like burrs (so-called whiskers) made of the foaming raw material M that has entered a large amount into the degassing vent are unlikely to occur.

The modified venting vent 30 is greatly shown in FIG. 3 so as to be emphasized, but actually, the opening width W1 of the opening 32 on the cavity 8 side may be 5 mm to 30 mm. Moreover, the narrow part (the protrusion part 36, the level | step difference part 46) should just be provided in 5-20 mm back (upper figure side) from the opening part 32. FIG.
The opening depths (D1, D2) of the modified vent hole 30 are emphasized in FIG. 4, but may actually be about 0.1 mm to 0.5 mm. For example, the depth D1 of the opening side bottom surface 34 of the modified gas vent 30 is set to 0.3 mm, while the depth D2 of the blocking wall side bottom surface 40 is set to 0.2 mm. With this depth setting, the thickness of the burrs generated in the parting line of the molded product (the strip-shaped burrs formed by entering the modified vent hole 30) is 0.2 mm to 0.00 mm. It becomes about 3 mm and can be bent easily. For this reason, depending on the molded product, the burr can be left as it is in the folded state (the operation for removing the burr becomes unnecessary).

As described above, according to the foam molding die 2 of the present embodiment, the upper mold 4 and the lower mold 6 are closed by the extending side portion 20 and the regulating portion 18 of the seal member 10 so that the foam raw material does not enter. By bringing the mating surfaces (4a, 6a) into close contact with each other, it is possible to satisfactorily prevent the formation of excessive burrs in the molded product. Further, according to the foam molding die 2, it is possible to reduce or prevent the foaming raw material from entering the modified gas venting vent 30 by the narrow portions (projecting portions 36, stepped portions 46) of the deformed venting vent 30. it can.
Therefore, according to the foam molding die 2, it is possible to satisfactorily prevent the formation of excessive burrs on the molded product (particularly, the portion corresponding to the particle line).

  And the foam molding die 2 of a present Example can shape | mold the seat cushion pad (an example of a molded product) of a vehicle seat satisfactorily. For example, urethane foam is poured into the cavity 8 of the foam molding die 2 using a soft foamed urethane high pressure injector. Then, the inside of the cavity 8 is heated for 5 to 10 minutes at a temperature setting of 65 ± 5 ° C. (preferable molding conditions) to foam and cure the foamed urethane, thereby foam-molding the seat cushion pad. By doing so, the seat cushion pad can be molded while satisfactorily preventing burr formation and beard formation. Then, after folding the strip-shaped burrs (thickness formed by the foaming raw material that has entered the atypical venting vent 30) formed on the seat cushion pad, the sheet cushion pad is actually covered with a skin material. It can be set as the seat cushion provided with the designability which can endure use.

The foam molding die 2 of the present embodiment is not limited to the above-described examples, and can take other various embodiments.
(1) In the embodiment, the example in which the sealing member 10 and the odd-shaped vent vent 30 are provided on the closing surface 6a of the lower mold 6 has been described. Unlike this, the sealing member 10 and the odd-shaped degassing vent 30 may be provided on the closing surface 4 a of the upper mold 4.
Further, in the present embodiment, the example in which the irregular vent hole 30 is formed in a concave shape on the surface of the seal member 10 and the external communication state is maintained has been described. Alternatively, apart from the sealing member 10 provided in the closed mating surface 6a of the lower mold 6, cut and closed mating surface 4a of the upper mold 4 in a concave shape may be provided with a different type degassing vent 30. Even in this configuration, the external communication state of the irregular vent hole 30 is maintained.
(2) In the embodiment, the example of the seal member 10 (having the two-layer structure) formed of the base layer 14 and the adhesion layer 12 has been described. Unlike this, the sealing member 10 may be configured by only one of the base layer 14 and the adhesion layer 12.
For example, when the sealing member 10 is constituted only by the adhesion layer 12, the adhesion side of the adhesion layer 12 (corresponding to the adhesion layer 12 of the embodiment) is maintained without containing an aluminum-based metal additive, and the adhesion layer An aluminum-based metal additive can be contained only on the 12 base portion side (corresponding to the base layer 14 of the embodiment).
(3) In the present embodiment, the example in which the protruding portions 36 are provided on both side surfaces of the narrow portion of the modified vent hole 30 has been described. Unlike this, the protruding portion 36 may be provided only on one side surface of the narrow portion, or a plurality of protruding portions 36 may be provided side by side. Further, the step portion 46 does not have to be a single step, and may be a plurality of steps. In the present embodiment, an example in which one portion of the opening width of the modified vent hole 30 is narrowed at the protruding portion 36 has been described. On the other hand, in the modified vent hole 30, the opening width from the narrow portion to the communication groove may be uniformly narrowed.

It is a longitudinal cross-sectional view of the mold for foam molding. It is a front view of a lower mold. It is a front perspective view of an unusual shape gas vent. It is a longitudinal cross-sectional view of a variant degassing vent. It is a partial longitudinal cross-sectional view of the mold for foam molding. It is a front perspective view of the modified gas venting vent of another example.

2 Mold for foam molding 4 Upper mold 6 Lower mold 8 Cavity 10 Sealing member 12 Adhesive layer 14 Base layer 18 Restricting part 20 Extension side part 30 Deformed venting vent 32 Opening part 36 Projection part (narrow part)
38 1st standing upper surface 42 Communication groove 44 Blocking wall 46 Step part (narrow part)
48 Second vertical surface 50 Discharge chamber 52 Discharge hole

Claims (2)

An upper mold and a lower mold that form a cavity by closing are provided, and the foaming gas generated from the foaming raw material in the cavity is externally provided by a strip-shaped recess provided on the closing surface of the upper mold or the lower mold. A mold for foam molding that can be discharged,
The foam molding die is formed by sealing the cavity while maintaining the external communication state of the strip-shaped recess by a sealing member provided in the circumferential direction of the closing surface of the upper die or the lower die. Configuration,
The sealing member is provided on an extending side portion extending into the cavity and the extending side portion, and the foaming raw material does not enter the closing portion of the upper mold and the lower mold. possess a regulating portion for regulating the flow of raw materials,
The strip-shaped concave portion is a foam molding die having a narrow portion in which an opening width and an opening depth are suddenly narrowed with respect to the opening portion on the cavity side . The sealing member has a base layer that is bonded and fixed to at least one closing surface of the upper mold and the lower mold, and an adhesion layer that is superimposed on the base layer and faces the other closing surface different from the one. And
The base layer is a resin layer containing an aluminum-based additive,
The mold for foam molding according to claim 1, wherein the adhesion layer is a rubber layer that is softer than the base layer without containing the aluminum-based additive .

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