JP2011218573A - Molding die, and method of manufacturing foamed molding using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding die preventing the deterioration of molding die quality by venting a proper amount of gas while maintaining the sealability of a cavity, and a method of manufacturing a foamed molding using the molding die.SOLUTION: The molding die 10 includes a packing 16 surrounding a cavity C at least on either one of split surfaces 18 of two split molding dies 12, 14 that are configured to openably/closably form the cavity C inside. The packing 16 is provided in a manner that at least a part of the packing protrudes from the split surface 18. Packing grooves 22 are formed on a protruded surface of the packing 16 as gas discharge passages for discharging gas in the cavity C. Each of the packing grooves 22 is formed in such a way that its bottom 22a is at a depth exceeding the split surface 18. This makes the discharge amount of gas to be a proper amount while preventing the large amount of foam material P from entering between the split surfaces 18, 20 by maintaining a proper discharge amount of gas.

Description

  The present invention relates to a molding die and a method for producing a foam molded body using the molding die, and in particular, one split surface of two split dies configured to be openable and closable so as to form a cavity therein. The present invention relates to a molding die in which a packing is provided so as to surround the periphery of a cavity, and a method of manufacturing a foam molded body such as a seat pad using the molding die.

  Conventionally, foam molded articles such as seat pads used in vehicles such as automobiles supply a synthetic resin foam material such as flexible polyurethane foam into a mold cavity formed by two divided molds such as an upper mold and a lower mold. Then, the cavity is sealed and the foam material inside is foamed and molded.

  In such a molding die, in order to obtain a stable product shape of the foam molded body, the foaming gas generated at the time of foam molding and the air remaining in the cavity are discharged to the outside of the cavity to perform foam molding. It is necessary to prevent the occurrence of lack of body and voids. As a technique for discharging the gas in the cavity, it is known to form a mold groove portion extending from the cavity to the outside of the mold on either one of the two divided molds of the mold (for example, Patent Document 1). Thereby, when manufacturing a foaming molding using a metal mold | die, the gas generated in a cavity is discharged | emitted from a groove part.

  On the other hand, a technique is known in which packing is provided so as to surround a cavity on a dividing surface of a mold (see, for example, Patent Document 2). According to this technique, the sealing performance at the dividing surface of the mold is improved, the generation of a large amount of burrs due to the leakage of the foam material from the inside of the cavity is prevented, and the deterioration of the quality of the foam molded product is prevented. However, in this technique, the sealing performance of the cavity is enhanced, but it is considered that there is a risk that a sufficient gas discharge amount may not be ensured.

JP 2003-181839 A JP 2006-35590 A

  However, in the technique for forming the mold groove in the mold described in the above-mentioned Patent Document 1 or the like, the sealing performance of the cavity on the divided surface is insufficient, and the divided surface of the foamed material, particularly the mold groove, is formed. There is a concern that the amount of infiltration increases, and as a result, the quality of the final foamed product is deteriorated. In addition, burrs are likely to occur, and post-processing may be required.

  On the other hand, in a mold in which a part without packing is formed around the cavity, a large pressure difference occurs between the part with packing and the notch in the packing, so a large amount of gas escapes from the notch in the packing. It is conceivable that a large amount of foam material may enter the notch portion of the packing and adversely affect the quality of the foamed molded product. On the other hand, it is conceivable to reduce the gas discharge amount by reducing the notch portion of the packing, but in that case, the gas escape is insufficient, and the molded body is likely to be thin and voided. there were. That is, the conventional technique has a big problem in that the gas discharge amount in the cavity is appropriately controlled.

  The present invention has been made in view of such circumstances, and an object of the present invention is to enable an appropriate amount of degassing while maintaining the sealing performance of the cavity, thereby preventing deterioration of the quality of the molded body. An object of the present invention is to provide a molding die and a method for producing a foam molded body using the molding die.

  In order to solve the above problems, the molding die according to claim 1 is a molding in which a packing is provided on at least one split surface of two split molds configured to be openable and closable so as to form a cavity therein. The packing is provided in a state where at least part of the packing protrudes from the dividing surface, and a packing groove portion serving as a gas discharge path for discharging gas in the cavity is provided on the protruding surface of the packing. The packing groove is characterized in that the bottom of the packing groove is formed to a depth exceeding the dividing surface.

  According to the molding die according to the present invention, a packing is provided around the cavity of the molding die to ensure sealing performance, while a groove is formed in the packing used for the purpose of maintaining this sealing performance. Forming a gas discharge path. Thereby, while maintaining the sealing performance of the cavity and suppressing a large amount of intrusion between the divided surfaces of the foamed material, a gas escape path can be secured by the packing groove and the gas discharge amount can be appropriately maintained. Therefore, it is possible to prevent adverse effects on the quality of the foamed molded product due to the occurrence of the lacking portion, and it is possible to prevent complicated post-processing such as burr removal.

  In particular, since the packing is generally formed of an elastic material or a flexible material, the process of providing the packing groove can be performed at low cost and with easy work. Therefore, gas can be adjusted by adjusting the size of the groove formed in the packing without processing the mold in accordance with the desired degassing amount determined according to various conditions such as the raw material conditions of the foam material and the mold temperature. The amount of extraction can be controlled easily and at low cost.

  According to a second aspect of the present invention, in the molding die according to the first aspect, a mold that extends from the cavity toward the outer side of the mold and communicates with the packing groove portion on the split surface of the split mold. A groove is formed.

  According to this, since the packing groove portion and the groove portion of the mold are formed as an integrated passage, the gas is discharged from the packing groove portion through the mold groove portion, so that the gas discharge effect can be enhanced. . In particular, the foam material pushed out between the divided surfaces can be concentrated in the mold groove by the exhaust gas flow. Therefore, since the penetration of the foam material between the divided surfaces can be made local, burrs generated in the molded body are also locally corresponding to the position of the mold groove, and post-processing is extremely easy. .

  According to a third aspect of the present invention, in the molding die according to the second aspect, the packing groove portion is formed to have a width smaller than the width of the mold groove portion in a plan view of the dividing surface. It is characterized by. According to this, it can prevent more reliably that gas discharge | emission amount increases excessively, can maintain moderate gas discharge | emission amount, and can improve a moldability.

  According to a fourth aspect of the present invention, in the molding die according to any one of the first to third aspects, the packing groove portion is disposed substantially uniformly over the entire area of the packing.

  According to this, degassing can be performed substantially uniformly from the entire cavity. That is, uneven pressure distribution in the cavity can be prevented, and more efficient gas discharge can be achieved while preventing local large burrs from being generated in the molded body.

  The method for producing a foam molded article according to claim 5 uses the molding die according to any one of claims 1 to 4 to inject a foam material in an open state of the split mold, and The foam material is foam-molded while the mold is closed and gas is discharged from the cavity through the packing groove.

  According to the present invention, a foaming material can be used while discharging gas in the cavity through the packing groove portion using the molding die according to claim 1, wherein an appropriate amount of gas can be released while maintaining sealing performance in the cavity. By performing the foam molding, it is possible to prevent complication of post-processing, and to suppress the occurrence of a lacking portion due to gas residue, and to obtain a good molded product.

  According to the molding die according to the present invention, the packing for ensuring the sealing performance of the cavity is arranged, and a groove is formed on the packing for ensuring the sealing performance to form the gas discharge path. That is, it is possible to suppress the large amount of the foam material from entering between the divided surfaces by maintaining the sealing property of the cavity, and to maintain an appropriate gas discharge amount. Therefore, it is possible to prevent adverse effects on the quality of the foamed molded product due to the occurrence of the lacking portion, and it is possible to prevent complicated post-processing such as burr removal.

  In addition, since the process of providing the packing groove can be easily performed at low cost, it is formed on the packing according to the desired degassing amount determined according to various molding conditions without the need to process the mold. By adjusting the size of the groove portion to be controlled, it is possible to control the amount of degassing easily and at low cost.

It is a figure explaining the structure of the metal mold | die for molding which concerns on this Embodiment. It is a figure explaining the principal part structure of the metal mold | die for shaping | molding in detail. It is an AA line schematic sectional drawing of FIG. (A) is the figure which looked at FIG. 2 from the B direction, (B) is the principal part enlarged view of (A). (A) has shown the use condition of the metal mold | die at the time of foam molding, (B) has shown the packing 16 part the enlarged view. It is a figure explaining the structure of the metal mold | die for a comparative example.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. FIG. 1 (A) schematically shows a molding die according to the present embodiment. As shown in the figure, the molding die 10 includes two split dies 12 and 14 configured to be opened and closed by a hinge 70. These split molds 12 and 14 form a cavity C as a molding space into which the foam material P is charged. A packing 16 is provided on the split surface 18 of the split mold (lower mold) 12 so as to surround the cavity C.

  The packing 16 is made of, for example, a known material having elasticity or flexibility, such as a rubber material such as nitrile rubber or fluororubber, or a resin material such as fluororesin. The packing 16 is provided with a base end portion 16 a partially embedded in the dividing surface 18 of the split mold 12 and an upper portion 16 b protruding from the dividing surface 18. With this configuration, when the split molds 12 and 14 are closed, the packing 16 has the upper surface 16b pressed against the split face 20 of the split mold (upper mold) 14 and deforms, whereby the split faces of the two split molds 12 and 14 are deformed. It functions to seal between 18 and 20.

  If the packing 16 protrudes from the dividing surface 18, a part of the packing 16 does not need to be embedded in the dividing surface 18, and the packing 16 is attached so as to be placed on the dividing surface 18 using a predetermined bonding means, for example. Also good.

  Hereinafter, a characteristic configuration of the present embodiment formed in the split mold 12 and the packing 16 in order to degas the inside of the cavity C generated during the foaming and molding process of the foam material will be described.

  FIG. 2 is a schematic plan view of the split mold 12 for explaining the characteristic configuration of the molding die 10, and FIG. 3 is a schematic cross-sectional view taken along the line AA of FIG. As shown in the figure, a packing accommodating recess 12b having a depth D1 is formed on the dividing surface 18, and the packing 16 is partially accommodated in the packing accommodating recess 12b.

  A plurality of packing grooves 22 are formed along the extending direction of the packing 16 on the surface portion of the packing 16 protruding from the dividing surface 18 as gas discharge passages. In the present embodiment, the packing 16 corresponding to each side of the cavity C formed in a substantially rectangular shape in plan view is provided with four packing grooves 22 on the long side and three on the short side. . And these packing groove parts 22 are arrange | positioned on the said each side part at substantially equal intervals, As a result, it has been in the state arrange | positioned substantially uniformly in the whole region of the packing 16. FIG. Moreover, the packing groove part 22 is formed so that it may extend substantially orthogonally with respect to the extending | stretching direction of each edge | side of the packing 16 of a substantially rectangular shape in planar view. The packing groove 22 preferably has a width W1 in a plan view of 1 to 30 mm, and a depth D2 of about 30 to 90% of the height H1 of the packing 16.

  According to the above configuration, by providing the packing 16 surrounding the cavity C, the sealing performance of the cavity C is ensured, while the packing groove portion 22 formed in the packing 16 used for maintaining the sealing performance. This ensures a gas discharge path.

  Therefore, the gas discharge amount can be properly maintained while maintaining the sealing property of the cavity C and suppressing a large amount of the foam material P from entering between the split surfaces 18 and 20, so that foaming due to the occurrence of the lacking portion is achieved. An adverse effect on the quality of the molded body can be prevented, and complication of post-treatment such as burr removal can be prevented.

  In particular, when a plurality of the packing groove portions 22 are formed substantially uniformly in the entire area of the packing 16 as described above, gas can be discharged substantially uniformly from the entire area in the cavity C. That is, it is possible to suppress the uneven pressure distribution in the cavity C and to more efficiently discharge the gas. Note that the number and arrangement position of the packing groove portions 22 are not limited to the above-described form, and can be appropriately changed according to various conditions such as molding conditions and the scale of the mold.

  Further, in the present embodiment, a ventilator 24 as a mold groove extending from the inside of the cavity C toward the outside of the mold is formed on the split surface 18 of the split mold 12 so as to communicate with each packing groove 22. . The ventilator 24 basically functions to allow the foam material to enter between the split surfaces 18 and 20 from the cavity C and to assist the packing groove portion 22 as a gas discharge path. The depth D3 of the ventilator 24 is preferably set to 0.2 mm to 1.0 mm, and more preferably set to 0.3 to 0.8 mm. Moreover, it is preferable that the width W2 in the planar view of the ventilator 24 is set to 2-30 mm.

  Therefore, since the packing groove 22 and the ventilator 24 form an integral gas discharge path, the gas discharge effect in the cavity C can be enhanced. In particular, since the ventilator 24 is a gas discharge path, the penetration of the foam material P between the divided surfaces 18 and 20 can be concentrated on the ventilator 24 by the force of the gas flow flowing into the ventilator 24. Accordingly, since the penetration of the foam material P between the divided surfaces 18 and 20 can be made local to the ventilator 24, burrs generated in the molded body are also locally corresponding to the position of the ventilator 24. The post-treatment after removing the burrs becomes extremely easy.

  In the present embodiment, since the ventilator 24 extends from the cavity C so as to communicate with the outside of the mold 10 via the packing 16, the gas passing through the packing groove portion 22 is allowed to flow through the ventilator 24. Is discharged to the outside of the mold 10 through the portion 24a located on the outer side of the mold with respect to the packing 16. That is, the ventilator 24 can more efficiently assist the gas discharge function of the packing groove 22.

  Furthermore, in the present embodiment, the width W1 of the packing groove portion 22 is formed to be smaller than the width W2 of the ventilator 24 for venting gas in the plan view of the split mold 12. According to this, since the gas flowing into the ventilator 24 from the inside of the cavity C is once squeezed at the portion of the packing groove portion 22, it is more reliably prevented that the gas discharge amount is excessively increased, and an appropriate gas The discharge amount can be maintained and the moldability can be improved.

  4A is a view schematically showing a state in which the molding die 10 is viewed from the direction A (mold side surface direction) in FIG. 3, and FIG. ) Is an enlarged view of main part (circled part). In addition, the dashed-dotted line in FIG.4 (B) shows the height position same as the height position of the division surface 18. FIG.

  As shown in the figure, the packing groove portion 22 of the packing 16 is formed to a depth at which the bottom portion 22 a extends beyond the dividing surface 18 of the dividing mold 12. Thereby, even when the molding die 10 is closed and the packing 16 is pressed and deformed by the split mold 14, the packing groove portion 22 is not crushed and is more reliably secured. Therefore, the gas in the cavity C can be discharged more stably. Furthermore, in this embodiment, the packing groove 22 is formed to a depth that does not reach the bottom 24 b of the ventilator 24. As a result, the packing groove portion 22 is enlarged, and the gas discharge passage is unnecessarily large, thereby preventing the gas from being excessively discharged, thereby achieving a more appropriate gas discharge amount and improving the moldability. it can.

  As described above, in the present embodiment, the packing groove 22 is formed on the packing 16 for maintaining the sealing state while maintaining the sealing state of the cavity C by the sealing property of the packing 16. As a result of discharging the gas, an excellent molded product with extremely high moldability (no voids or lacking parts) can be obtained.

  FIG. 5 (A) is a view showing a state where the foam material P is foam-molded using the molding die 10 having the above-described configuration, and FIG. 5 (B) is an enlarged view of the packing 16 portion. . As can be seen from the figure, the seal 16 in the cavity C is secured by the packing 16 deformed between the dividing surfaces 18 and 20, and in this state, gas is discharged from the packing groove 22 and the ventilator 24 while foaming. Molding is performed. In the closed state of the molding die 10, the gap H2 between the bottom portion 22a of the packing groove 22 and the surface 14a of the split die 14 that is the upper die is about 0.3 mm to 0.8 mm. Each dimension such as the depth of the packing groove 22 is preferably adjusted.

  Further, in the present embodiment, the width (W1), the depth (D2), etc. of the packing groove portion 22 are adjusted without performing special processing in accordance with various conditions such as the raw material conditions of the foam material and the mold temperature. The gas discharge amount can be easily controlled to an appropriate amount according to various conditions such as the raw material conditions of the foam material and the mold temperature. Therefore, for example, when it is necessary to increase the amount of gas discharged, such as when the type of foaming material to be molded using the same molding die 10 is changed, the size of the packing groove 22 is expanded (packing 16 The gas passage area can be changed and the gas discharge amount can be increased. In addition, you may make it change the magnitude | size of the packing groove part 22 by replacing | exchanging the packing 16 whole. Thereby, the magnitude | size of the packing groove part 22 can be adjusted more easily.

  Further, in order to ensure good sealing performance by the packing 16, the volume of the packing 16 as a whole is slightly larger than the volume of the portion of the packing 16 accommodated in the packing accommodating recess 12 b when the molding die 10 is closed. It is preferable to set it to a large extent.

  Hereinafter, a comparison is made between a foam molded body manufactured using the molding die 10 according to the present invention and a foam molded body manufactured using a conventional molding die.

(Comparative example)
As shown in FIG. 6, a packing 102 is provided around the cavity C on the dividing surface 101 of the molding die 100. A part of the notch 104 is formed in the packing 102, and gas is discharged from the notch 104. The width W3 in plan view of the cutout portion 104 of the packing 102 was 25 mm.

  Of the 50 products manufactured using this molding die 100, 23 were defective. In particular, the amount of intrusion of the foamed material between the split surfaces due to excessive gas removal at the cutout portion 104 of the packing 102 increases, and post-treatment for removing burrs is complicated for many products.

(Example)
In the molding die 10 in the above embodiment, the height H1 (see FIGS. 3 and 4) of the packing 16 is 7 mm, the width W1 in the plan view of the packing groove 22 is 5 mm, and the depth D2 is 3 mm. On the other hand, the width W2 of the ventilator 24 formed on the dividing surface 18 of the molding die 10 is 5 mm, the depth D3 is 0.5 mm, and the depth D1 of the packing accommodating recess 12b is 4.0 mm. In addition, by setting the dimensions of the packing groove portion 22 and the ventilator 24 as described above, the bottom portion 22a of the packing groove portion 22 and the bottom portion 24b of the ventilator 24 are substantially flush with each other in the depth direction.

  In the molding die 10, the configuration related to the size other than the size of the packing 16 and the ventilator 24 is considered to affect the required amount of gas discharge and the amount of intrusion of the foam material into the dividing surface (the size of the cavity, The overall size of the mold and the material of the packing, etc.) were almost the same as the mold 100 of the comparative example. That is, this is because the difference in the gas discharge amount and the intrusion amount of the foamed material into the split surface between the molding die 10 of this embodiment and the comparative mold 100 is due to the structure of the packing 16 and the ventilator 24. The conditions are set so as to make it clear as much as possible that it is caused by the difference between the two.

  When the molding material 10 was used to mold the foam material P, it was possible to suppress the occurrence of a lacking portion and voids and to concentrate the generation of burrs locally on the ventilator 24. . In molding using this molding die 100, it was possible to make one defective product out of 50 manufactured products. Therefore, the number of defective products was successfully reduced by 44% compared to the comparative example.

  In addition, this invention is not limited to the said embodiment, A various change is possible within the range of the summary of invention. For example, the dimensions and shapes such as the width (W1, W2) and depth of the packing groove portion 22 of the packing 16 and the ventilator 24 of the mold 10 are in accordance with various molding conditions such as the raw material conditions of the foam material P and the mold temperature. It can be changed as appropriate.

  The ventilator 24 can be formed to have an arbitrary length as long as the ventilator 24 is formed so as to communicate with at least the inside of the cavity C and extend outward from the mold. For example, in the present embodiment, the length is formed so as to communicate from the inside of the cavity C to the outside of the mold 10 via the packing groove portion 22, but the present invention is not limited to this. You may form in the length which does not reach.

  Further, in the present embodiment, the packing 16 and the ventilator 24 having the packing groove portion 22 are provided in the split mold 12 which is the lower mold, but these may be applied to the split mold 14 which is the upper mold. In addition, the packing 16 and the ventilator 24 may be provided in both the split mold 14 that is the upper mold and the split mold 12 that is the lower mold, and a plurality of packings 16 are provided on the split surface of one split mold. It may be arranged in parallel.

  Further, in the present embodiment, as shown in FIG. 2, the packing groove portion 22 is formed so as to be substantially orthogonal to the extending direction of one side of the packing 16 having a substantially rectangular shape in a plan view. If the packing groove portion 22 can function as a gas discharge path, the packing groove portion 22 may be formed so as to cross and extend without being orthogonal to the extension direction of the packing 16, for example. good.

  Further, the ventilator 24 is not an essential component of the present invention, and the molding die 10 may be configured without forming the ventilator 24.

DESCRIPTION OF SYMBOLS 10 Mold 12 Dividing die 14 Dividing die 16 Packing 18 Dividing surface 22 Packing groove part 24 Ventilator (die groove part)
C cavity P foam material

Claims (5)

A molding die in which packing is provided on at least one split surface of two split molds configured to be openable and closable so as to form a cavity therein,
The packing is provided in a state in which at least a part thereof protrudes from the dividing surface,
On the protruding surface of the packing, a packing groove is formed as a gas discharge path for discharging the gas in the cavity.
The molding groove characterized in that the packing groove portion has a bottom portion formed at a depth exceeding the dividing surface. In the split surface of the split type,
The mold for molding according to claim 1, wherein a mold groove extending from the cavity toward the outside of the mold and communicating with the packing groove is formed. The packing groove is
3. The molding die according to claim 2, wherein the molding die is formed to have a width smaller than a width of the die groove portion in a plan view of the dividing surface. The packing groove is
The molding die according to any one of claims 1 to 3, wherein the molding die is disposed substantially uniformly throughout the packing. Using the molding die according to any one of claims 1 to 4,
Injecting foam material in the open state of the split mold,
A method for producing a foamed molded product, wherein the split mold is closed and foaming of the foamed material is performed while gas is discharged from the cavity through the packing groove.

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