JP5103121B2 - Core vent used for foam molding and foam molding method - Google Patents

Description

  The present invention relates to an improvement in a core vent used in a foam mold and a foam molding method.

Conventionally, a foaming thermoplastic resin particle is filled in a molding space (cavity) between two foaming molds (core mold and cavity mold), and steam as a heating medium is placed in the molding space to heat and expand the particles. A foam molding method is known. In this method, a large number of core vents are attached to the molding die, and steam is caused to flow into the molding space from the steam holes of the core vent (for example, Patent Document 1 below). Moreover, many unevenness | corrugations are formed in the inner surface of a foaming mold, and this unevenness | corrugation pattern is transcribe | transferred to the surface of a foaming molding.
JP 2005-51979 A

  As described above, there is an advantage that the turtle shell pattern due to the foam particles becomes inconspicuous when the concavo-convex pattern is transferred to the surface of the foam molded body, but a large number of circular patterns due to a large number of core vents are simultaneously formed on the surface of the foam molded body. Therefore, there is a problem that the pattern of the core vent becomes conspicuous.

  Therefore, the present invention has been made in view of the above-described conventional problems, and in using a foam molding die having a large number of irregularities on the inner surface, by making the pattern caused by the core vent generated on the surface of the foam molded article less noticeable. An object is to further improve the aesthetics of the foamed molded product.

The present invention has been made to solve the above-mentioned problems, and the core vent used in the foam molding die according to the present invention is in the molding space when mounted on the foam molding die having a large number of irregularities on the inner surface. on one end face facing to a Koabento a large number of steam holes are opened, the end surface is concave than the opening of the convex portion and the steam holes than the opening of the steam holes forwardly projecting recessed rearward Are formed, and the opening of the steam hole is located in the convex portion of the convex portion and the concave portion on the one end surface .

The core vent having the above structure is mounted on a foam mold having a large number of irregularities formed on the inner surface, and foam molding is performed. In this mounted state, a large number of vapor holes are opened on one end surface of the core vent facing the molding space. Therefore, the steam flows into the molding space through the steam hole of the core vent. The one end surface of the core vent is formed with a plurality of convex portions protruding forward from the opening of the steam hole or concave portions recessed rearward from the opening of the steam hole. One end surface is not a flat surface but an uneven surface. Therefore, a concavo-convex pattern is formed in the portion corresponding to the core vent on the surface of the obtained foamed molded body, like the other portions.
Further, since the opening of the steam hole is located in the convex part of the convex part and the concave part on the one end surface, the opening of the steam hole is not on the concave part side but on the convex part side, and the opening is positioned forward of the concave part. Therefore, the release air coming out from the opening of the steam hole flows along the concave shape of the foam molded body, and the foam molded body easily floats from the foam mold and has excellent releasability.

In the core vent of the present invention, the convex portion may be formed of a ridge extending in two directions, and a steam hole opening may be formed at a crossing portion where the ridges in the two directions intersect .

  As described above, a large number of convex portions projecting forward from the opening of the vapor hole or concave portions recessed rearward from the opening of the vapor hole are formed on one end surface of the core vent. A pattern will be formed, the pattern resulting from the contour of the one end face of the core vent will be less noticeable, and the appearance of the foamed molded product can be enhanced.

Hereinafter, an embodiment of a core vent according to the present invention will be described with reference to the drawings.
FIG. 1 to FIG. 3 show the core vent in the present embodiment. The core vent 1 is generally cylindrical, and has a disk-shaped wall portion 2 of a predetermined thickness on one end side, and the other end. The side is open. That is, a large circular hole 3 coaxial with the axis T of the core vent 1 is formed in a counterbore shape on the other end side of the core vent 1, and the depth of the large hole 3 is the entire length of the core vent 1 in the axial direction. Since it is more than half, the thickness of the disk-shaped wall surface portion 2 is less than half of the total length of the core vent 1 in the axial direction. The wall surface portion 2 is formed with a large number of round steam holes 4 extending in the axial direction so as to penetrate the wall surface section 2, and the steam holes 4 communicate with the large hole 3 on the other end side. Therefore, the steam flows from the large holes 3 into the respective steam holes 4 and exits from the openings 4 a of the steam holes 4 in the one end face 5 of the core vent 1. Although the number of the vapor | steam holes 4 is arbitrary, it is 5-30 pieces (preferably 6-24 pieces), for example.

  As described above, the one end surface 5 of the core vent 1 has a large number of openings 4a of the steam holes 4, but the one end surface 5 is not a flat surface but an uneven surface. That is, a plurality of ridges 6 extending in two orthogonal directions are formed on the one end surface 5 of the core vent 1 at predetermined intervals, and each ridge 6 is linear and extends from one end of the circular end surface 5 to the other end. Is formed. Accordingly, the two-way ridges 6 are formed on the one end surface 5 in a lattice shape, so that the square area defined by the two-way ridges 6 is a recess 7. Since the height of each protrusion 6 is constant, the depth of all the recesses 7 is also constant, and the bottom surface of the recesses 7 is flat. The protrusion 6 has a triangular cross section, and the apex angle is an acute angle. The pitch between the ridges 6 is, for example, 1 to 4.5 mm (more preferably 1.5 to 4 mm), and the height of the ridges 6 is, for example, 0.3 to 2 mm (more preferably 0.8 to 1). .2 mm).

  And the opening 4a of the said vapor hole 4 is formed in the crossing part 8 where the protrusion 6 of two directions crosses. Therefore, the recessed part 7 is located behind the opening 4a of the vapor hole 4, in other words, the opening 4a is on the protruding part side. As shown in FIG. 3, the openings 4a of the vapor holes 4 are located in all the intersecting portions 8 existing in the circular region corresponding to the large hole 3, and the intersecting portions located outside the region. 8 does not have the opening 4a of the vapor hole 4. Further, the diameter of the opening 4 a of the vapor hole 4 is smaller than the width of the protrusion 6.

  The core vent 1 is generally formed of a metal such as brass, aluminum, an aluminum alloy, or slenless, but a resin can also be used. Moreover, in order to suppress adhesion of foamed resin, it is preferable to use a coated product. Further, the core vent 1 generally has a diameter of several mm to several tens of mm (for example, 6 to 10 mm), and the vapor hole 4 has a diameter of, for example, 0.5 to 1.5 mm (more preferably, 0.8 to 1.2 mm) is used.

  The core vent 1 configured as described above is mounted in a large number on the foam molding die 12 (foam molding die) so that one end surface 5 thereof faces the molding space 11 (cavity). Specifically, As shown in FIG. 4, it is fitted into the through hole 13 formed in the foaming mold 12 by press fitting. Then, the steam passes from the chamber 14 through the large holes 3 of the core vent 1 and the respective steam holes 4, and steam is introduced into the molding space 11. In FIG. 4, the thickness of the foam molding die 12 is substantially equal to the total axial length of the core vent 1, and therefore the one end surface 5 of the core vent 1 is substantially flush with the inner surface 12 a of the foam molding die 12. For example, aluminum or stainless steel is used as the mold material.

  In the inner surface 12a of the foam molding die 12, the turtle shell pattern on the surface of the foam molded body is made inconspicuous, or when the foam molded body is rubbed against other members that are close to each other in use, suppression of rubbing noise is suppressed. Therefore, a large number of irregularities are formed. Various methods can be used for forming the irregularities. For example, in the case of a method of creating a sand mold from a wooden mold (original mold) and casting the foaming mold 12 from the sand mold, a synthetic resin is used for the wooden mold. An uneven pattern can be formed on the inner surface 12a of the foam molding die 12 by attaching a conductive mesh sheet and sequentially transferring the uneven pattern. In addition to using a mesh sheet, a wire mesh or punching metal can also be used. FIG. 4 shows a case where the height (depth) of the unevenness of the foaming mold 12 is equal to the height of the protrusion 6 of the core vent 1.

  Using the foam molding die 12 as described above, a foam molded article made of, for example, a polystyrene resin, a styrene modified polyethylene resin, a styrene modified polypropylene resin, a polyethylene resin, a polypropylene resin, a polylactic acid resin, or the like. When (for example, an automobile interior member) is formed by molding, the concavo-convex pattern on the inner surface 12a of the foam molding die 12 is transferred to the surface of the foam molded body, and the concavo-convex pattern on the one end surface 5 of the core vent 1 is also transferred. . Therefore, since the concavo-convex pattern is formed on the entire surface of the foam molded article, the tortoiseshell pattern is not conspicuous on the surface, and at the same time, the circular pattern that is the outline of the one end face 5 of the core vent 1 is not conspicuous. A foamed molded product can be obtained. Since many of the core vents 1 are used, many patterns of the core vents 1 are likely to be present on the surface of the foam molded article. However, since the patterns of the core vents 1 are less noticeable, a good overall appearance can be obtained. It is done.

  Moreover, since the opening 4a of the vapor hole 4 is provided in the protrusion 6, release air flows along the convex shape of the foam molding die 12, that is, the concave shape of the foam molded body, and the foam molding metal of the foam molded body. The releasability from the mold 12 is improved. In particular, since the opening 4a is provided in the crossing portion 8, the release air flows in all directions, and the releasability is further improved.

  In addition to providing the opening 4 a of the vapor hole 4 in the crossing portion 8, for example, the vapor hole 4 may be provided in a portion of the ridge 6 other than the crossing portion 8 or in the bottom surface of the recess 7. When the opening 4 a of the steam hole 4 is provided on the bottom surface of the recess 7, the protrusion 6 projects forward from the opening 4 a of the steam hole 4.

  Moreover, although the case where the round vapor hole 4 was formed was demonstrated, it is good also as a slit-shaped vapor hole 4. FIG.

  Furthermore, although the two ridges 6 are orthogonal, they may be crossed at an acute angle, or the ridges 6 may be provided only in one direction.

  Further, the ridge 6 is not linear but wave-shaped, or instead of the ridge 6, a large number of convex portions such as round shapes and square shapes are provided, or conversely, concave portions 7 such as round shapes and square shapes are provided. It may be recessed.

The perspective view which shows the core vent which concerns on one Embodiment of this invention. The side view containing the partially broken line of the same core vent. The front view of the core vent. Sectional drawing which shows the state which mounted | wore the foam molding die with the same core vent.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Core vent, 2 ... Wall surface part, 3 ... Large hole, 4 ... Steam hole, 4a ... Opening, 5 ... One end surface, 6 ... Projection, 7 ... Recessed part, 8 ... Crossing part, 11 ... Molding space, 12 ... Foaming Mold (molding mold), 13 ... through hole, 14 ... chamber

Claims (3)

A core vent in which a large number of vapor holes are opened on one end surface facing the molding space in a mounting state on a foaming mold in which a large number of irregularities are formed on the inner surface,
The one end surface is formed with a plurality of convex portions protruding forward from the opening of the vapor hole and concave portions recessed rearward from the opening of the vapor hole, and the vapor hole is formed in the convex portion of the one end surface and the concave portion. A core vent used in a foam molding die, characterized in that the opening of is located . 2. The core vent according to claim 1 , wherein the convex portion is formed of a ridge extending in two directions, and an opening of a vapor hole is formed at a crossing portion where the two ridges intersect .   A foam molding method using a foam molding die having a plurality of irregularities formed on the inner surface and provided with the core vent according to claim 1.

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