JP4077871B2 - Hollow double wall molded article and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hollow double wall molded article having a hollow double wall structure obtained by blow molding a thermoplastic resin and having a partition wall integrally connecting the one wall and the other wall in the hollow portion, and It relates to the manufacturing method.
[0002]
The hollow double wall molded product according to the present invention is used for housing equipment, furniture panels, home appliance housings, office equipment housings, automotive supplies panels, and the like.
[0003]
[Prior art]
Housing equipment includes bathroom panels, washstands, wall materials, partitions, entrance doors, and furniture panels include desk tops, partition panels, and bookshelves. Further, the housing of the home appliance includes a refrigerator housing, a television housing, and the like. The housing of office equipment includes a housing of a copying machine and its door. Examples of automobile panels include console box lids, bonnets, and doors.
[0004]
And, since housing equipment, furniture panels, household appliance housings, office equipment housings, automotive parts panels, etc. are often required to have high rigidity, one wall of the hollow double wall structure and the other The thing of the structure which integrated the wall with the concave rib formed toward the one wall from the other wall is used (refer Unexamined-Japanese-Patent No. 7-195559).
[0005]
[Problems to be solved by the invention]
In housing equipment, furniture panels, home appliance housings, office equipment housings, automobile supplies panels, etc., the appearance may be asked not only on the front side but also on the back side. In the case of such a panel, when high rigidity is required, one wall and the other wall are formed in blow molding in order to integrate the one wall and the other wall of the hollow double wall structure. In order to form a partition wall (so-called inner rib) in which a part of the other wall is protruded until it comes into contact with the one wall and is integrally connected in the hollow portion (see FIGS. 1 and 3).
[0006]
By the way, the partition wall described above is arranged such that a thermoplastic resin parison is placed between a pair of split molds and the mold is clamped, and a slide core provided in the other mold is advanced to move one part of the other wall to one side. After projecting until they touch each other wall and welding both walls, the slide core is retracted to the cavity surface of the other mold, and the side surfaces of the projecting walls are welded to each other by blow pressure. Since the process of forming an integral partition wall with the other wall is followed, in the process in which the protruded wall becomes the partition wall integrated by the blow pressure, the partition wall becomes the part of the other mold. The blow pressure is received without supporting the cavity.
[0007]
For this reason, since the joint surfaces of the partition walls appear to wave along the cavity of the other mold due to the geographical variation of the blow pressure, the other wall of the hollow double wall structure On the outer surface, a wavy line appears at a portion corresponding to the partition wall, and the appearance is impaired.
[0008]
Therefore, the present invention is to place a thermoplastic resin parison between a pair of split molds and clamp the mold, and to advance a slide core provided in the other mold, thereby moving a part of the other wall to one wall. After projecting until it touches and welding both walls, the slide core is retracted to a position slightly projecting from the cavity surface of the other mold, and pressure fluid is introduced into the parison to make the parison a pair of molds. By forming the shape along the cavity surface and welding the side surfaces of the walls protruded by blow pressure to form an integral partition wall between one wall and the other wall, The part that becomes the partition wall in the process of forming the integral partition wall between the one wall and the other wall by welding the side surfaces of the protruded walls to each other by the blow pressure is the tip of the slide core. Mold cavity Supports and reliably prevents the appearance of wavy lines at the part corresponding to the partition wall on the outer surface of the other wall, and the appearance of not only the outer surface of one wall but also the outer surface of the other wall is excellent. An object of the present invention is to provide a hollow double wall molded product.
[0009]
In addition, the present invention provides a method for producing a hollow double wall molded product that can reliably obtain a hollow double wall molded product that is excellent not only in the outer surface of one wall but also in the outer appearance of the other wall. The purpose is to do.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a hollow double wall molded article according to claim 1 of the present invention is a molded article having a hollow double wall structure obtained by blow molding a thermoplastic resin, and forms a partition wall. A partition consisting of a wall in which a part of the projected other wall is welded in contact with the one wall at the top end surface and the both side surfaces are pressed together and integrally welded by advancing and retracting the slide core. wall is formed so as to connect integrally the one wall and the other wall in the hollow portion, the portions corresponding to the other wall of the outer surface of the partition walls, the width of the open end is located at 1~5mm In addition, a concave groove shallower than the thickness of the other wall is formed.
[0011]
The hollow double-wall molded product according to claim 2 of the present invention is the structure of claim 1, and the concave groove formed in the portion corresponding to the partition wall on the outer surface of the other wall has a depth of 0.1 It is 2 mm, and the width of the opening end is narrower than the width of the partition wall .
[0012]
The hollow double-wall molded product according to claim 3 of the present invention is the structure of claim 1 or 2, wherein the concave groove formed in the part corresponding to the partition wall on the outer surface of the other wall is in the depth direction. It is characterized by being formed so as to have a narrow width.
[0013]
A method for producing a hollow double-wall molded product according to claim 4 of the present invention is a method for obtaining a molded product having a hollow double-wall structure by blow-molding a thermoplastic resin, between a pair of split molds. A thermoplastic resin parison is placed and clamped, and a slide core forming a partition wall provided in the other mold is advanced to project a part of the other wall until it touches one wall. After the wall is welded, the slide core that forms the partition wall is retracted to a position that slightly protrudes from the cavity surface of the other mold, and pressure fluid is introduced into the parison so that the parison is cavityd between the pair of molds. After forming the shape along the surface and welding the side surfaces of the protruded walls together by blow pressure to form an integral partition wall between one wall and the other wall, a pair of gold Special feature is to open the mold and take out the molded product It is an.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a partially broken perspective view showing a hollow double wall panel according to an embodiment of the present invention, and FIG. 2 is a partial sectional view thereof. 3 and 4 show a blow molding aspect of a hollow double wall panel according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view showing a process in which a slide core that forms a partition wall is advanced during mold clamping. FIG. 4 and FIG. 4 are cross-sectional views showing the process of retracting the slide core. FIG. 5, FIG. 6 and FIG. 7 each show another embodiment of the present invention, and are cross-sectional views showing a process in which a slide core forming a partition wall is advanced after clamping.
[0015]
In FIG. 1 and FIG. 2, 1 is a hollow double-wall molded product, and this hollow double-wall molded product 1 is obtained by blow molding a thermoplastic resin. One wall 2 and the other wall 3 constituting the hollow double wall molded article 1 are integrated by a partition wall 4 formed from the other wall 3 toward the one wall 2. 5 is a hollow part.
[0016]
The partition wall 4 is an inner rib formed by projecting a part of the other wall 3 of the hollow double-wall molded product 1 until it comes into contact with one wall 2, and the inner rib refers to one wall 2 and the other wall 2. It is a wall that is in the hollow portion 5 between the wall 3 and is integrally connected by a welded portion 7 on the side surface.
[0017]
A groove 6 is formed in a portion corresponding to the partition wall 4 on the outer surface of the other wall 3. This concave groove 6 is narrower than the width of the partition wall 4 and extremely shallow compared to the thickness of the other wall 3, and is formed by the tip of a slide core (described later) involved in the formation of the partition wall 4. Is done.
[0018]
The depth of the concave groove 6 is 0.1 to 2 mm, and the width of the open end is 1 to 5 mm. When the depth of the concave groove 6 is less than 0.1 mm, the support for the cavity of the other mold (described later) of the part to be the partition wall 4 is insufficient, and if it exceeds 2 mm, the molded product is released from the mold. May cause trouble. In addition, as will be described later, when the width of the concave groove 6 is less than 1 mm, the part that becomes the partition wall 4 in the process of forming the integral partition wall 4 by the blow pressure is the other mold at the tip of the slide core. The effect of supporting the cavity 3 is insufficient, and if it exceeds 5 mm, the appearance of the outer surface of the other wall 3 is impaired.
[0019]
The thermoplastic resin constituting the hollow double-wall molded article 1 according to the present invention may be any one that can be blow-molded, but is not limited to high density polyethylene resin, medium density polyethylene resin, polypropylene resin, modified polyphenylene oxide resin, polycarbonate resin. Polyamide resin, polystyrene resin, ABS resin and the like are preferable.
[0020]
As shown in FIGS. 3 and 4, the hollow double wall molded article 1 according to the present invention is manufactured by blow molding a thermoplastic resin. In these drawings, a pair of split molds consists of one mold 11 and the other mold 12, and one mold 11 connects one wall 2 of the hollow double wall panel 1 and the other mold 12. Has a cavity for molding the other wall 3. The other mold 12 is provided with a slide core 13 for forming the partition wall 4.
[0021]
In order to blow-mold the hollow double-wall molded product 1 with the pair of split molds, a parison 14 is disposed between one mold 11 and the other mold 12, and a pair of pairs as shown in FIG. Tighten the split mold. Then, the slide core 13 is advanced, and a part of the part that becomes the other wall 3 of the parison 14 is protruded until it comes into contact with a part that becomes the one wall 2 of the parison 14, and the top end face 8 of the parison 14 It welds to the part which becomes the wall 2.
[0022]
Next, as shown in FIG. 4, the slide core 13 is retracted to a position slightly protruding from the cavity surface of the other mold 12, and in that state, a pressure fluid is introduced into the parison 14, and the internal pressure is increased. Is increased, the parison 14 is pressure-bonded to the cavities of one mold 11 and the other mold 12. Further, the protruding portion of the portion that becomes the other wall 3 of the parison 14 forms a partition wall 4 by forming a welded portion 7 in which both side surfaces are pressed together and integrally welded. As shown in FIG. 4, both side surfaces of the protruding wall are welded and integrated with each other, and the top end surface 8 is welded to one wall 2.
[0023]
The blow-molded hollow double wall molded product 1 is taken out after the pair of molds are cooled.
[0024]
In the above blow molding step, the part that becomes the partition wall 4 is supported by the protruding tip end portion of the slide core 13 with respect to the cavity of the other mold 12, so that in the process of forming the integral partition wall 4, Even if the pressure is applied, the partition wall 4 does not shift along the cavity surface of the other mold 12, and a wavy line appears at a portion corresponding to the partition wall 4 on the outer surface of the other wall 3. It can be surely prevented from coming out. For this reason, the hollow double wall molded article 1 excellent in the appearance of not only the outer surface of one wall 2 but also the outer surface of the other wall 3 is obtained.
[0025]
5, FIG. 6 and FIG. 7 show other embodiments of the method for producing a hollow molded article according to the present invention. In these other embodiments, only the tip shape of the slide core 13 is different from that shown in FIGS. 3 and 4, and other aspects are the same as those shown in FIGS. 3 and 4. Therefore, the same reference numerals are given to the parts of the same mode, and the description thereof will be omitted.
[0026]
In the embodiment shown in FIG. 5, the tip of the slide core 13 has a narrowed shape. Thereby, since the width | variety of the ditch | groove 6 can be formed narrowly, the external appearance property of the outer surface of the other wall 2 is favorable. In the embodiment shown in FIG. 6, the width of the distal end portion of the slide core 13 is narrowed in the distal direction. And by doing in this way, since the ditch | groove 6 formed in the site | part corresponding to the partition wall 4 of the outer surface of the other wall 3 is formed so that a width | variety may become narrow in the depth direction, Release is smooth. Further, in the embodiment shown in FIG. 7, the tip of the slide core 13 has a shape that gradually decreases in width toward the tip, and the groove 6 has a partition wall even if the opening side is shallow. Since the part corresponding to the welding surface 8 of 4 can be formed deeply, the effect of preventing the appearance of wavy lines is further improved.
[0027]
【The invention's effect】
According to the present invention, a parison of a thermoplastic resin is placed between a pair of split molds and clamped, and a slide core provided on the other mold is advanced to make a part of the other wall part of one wall. After projecting until it touches and welding both walls, the slide core is retracted to a position slightly projecting from the cavity surface of the other mold, and pressure fluid is introduced into the parison to make the parison a pair of molds. By forming the shape along the cavity surface and welding the side surfaces of the walls protruded by blow pressure to form an integral partition wall between one wall and the other wall, The part that becomes the partition wall in the process of forming the integral partition wall between the one wall and the other wall by welding the side surfaces of the protruded walls to each other by the blow pressure is the tip of the slide core. Into the mold cavity To prevent the wavy line from appearing in the part corresponding to the partition wall on the outer surface of the other wall, and to improve the appearance of not only the outer surface of one wall but also the outer surface of the other wall. A hollow double-wall molded product can be provided.
[Brief description of the drawings]
FIG. 1 is a partially broken perspective view showing a hollow double wall molded article according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional view of a hollow double wall molded article according to an embodiment of the present invention.
FIG. 3 is a partial cross-sectional view showing a blow molding aspect of a hollow double-wall molded product according to an embodiment of the present invention and showing a process in which a slide core that forms a partition wall is advanced during mold clamping.
FIG. 4 is a partial cross-sectional view showing a blow molding aspect of a hollow double wall molded article according to an embodiment of the present invention and showing a step of retracting a slide core.
FIG. 5 is a partial cross-sectional view showing a blow molding aspect of a hollow double-wall molded product according to another embodiment of the present invention and showing a step of retracting the slide core.
FIG. 6 is a partial cross-sectional view showing a blow molding aspect of a hollow double wall molded article according to still another embodiment of the present invention and showing a step of retracting the slide core.
FIG. 7 is a partial cross-sectional view showing a blow molding aspect of a hollow double-wall molded product according to still another embodiment of the present invention and showing a step of retracting the slide core.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hollow double wall molded product 2 One wall 3 The other wall 4 Partition wall 5 Hollow part 6 Groove 7 Welding part 8 Top end surface 11 One metal mold 12 Other metal mold 13 Slide core 14 Parison

Claims (4)

A hollow double-walled molded product obtained by blow molding a thermoplastic resin,
When the slide core forming the partition wall is advanced and retracted, a part of the projected other wall is welded in contact with the one wall at the top end surface, and both side surfaces thereof are pressed against each other and welded together. was being formed so as to connect integrally the one wall and the other wall partition wall consisting of wall within the hollow section,
A hollow groove characterized in that a groove corresponding to the partition wall on the outer surface of the other wall has an opening end width of 1 to 5 mm and is shallower than the thickness of the other wall. Heavy wall molded product. The groove formed in a portion corresponding to the partition wall on the outer surface of the other wall has a depth of 0.1 to 2 mm, and an opening end is narrower than the partition wall. 1. A hollow double wall molded article according to 1.   The hollow double wall molding according to claim 1 or 2, wherein the groove formed in a portion corresponding to the partition wall on the outer surface of the other wall is formed to have a narrow width in the depth direction. Goods. A method of blow molding a thermoplastic resin to obtain a hollow double-walled molded article,
Place a thermoplastic resin parison between a pair of split molds, clamp the mold, and advance a slide core that forms a partition wall provided on the other mold, so that a part of the other wall is placed on one wall. After projecting to contact and welding both walls, the slide core that forms the partition wall is retracted to a position slightly projecting from the cavity surface of the other mold,
While introducing pressure fluid into the parison and forming the parison into a shape that fits the cavity surface of a pair of molds,
The side surfaces of the protruded walls are welded together by blow pressure to form an integral partition wall between one wall and the other wall, and then a pair of molds are opened to take out the molded product A method for producing a hollow double wall molded product.

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