JP2000108198A - Hollow double-wall molding and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow double-wall molding having excellent appearance not only on an outer surface of one wall but also an outer surface of the other wall, and a method for manufacturing it. SOLUTION: The hollow double-wall molding 1 has a hollow double-wall structure obtained by blow molding a thermoplastic resin. A partition wall 4 for integrally connecting the one wall 2 to the other wall 3 in a hollow part 5 by projecting a part of the wall 3 until the wall 3 is brought into contact with the wall 2 is formed. A groove 6 which is narrower than a width of the wall 4 and shallow is formed at a site corresponding to the wall 4 of the outer surface of the wall 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow double-walled structure obtained by blow-molding a thermoplastic resin and having a partition wall integrally connecting one wall and the other wall in a hollow portion. The present invention relates to a double-walled molded product and a method for producing the same.

[0002] The hollow double-walled molded product according to the present invention is used for housing equipment, furniture panels, home electric appliance housings, office equipment housings, automobile supply panels, and the like.

[0003]

2. Description of the Related Art Household equipment includes bathroom panels, wash basins, wall materials, partitions, entrance doors, and the like, and furniture panels include desk tops, partition panels, and bookshelves. Further, the housing of the home electric appliance includes a housing of a refrigerator, a housing of a television, and the like. The housing of the office equipment includes a housing of a copying machine and a door thereof. Panels for automobiles include console box lids, bonnets and doors.

[0004] Since high rigidity is often required for housing equipment, furniture panels, housings for home appliances, housings for office equipment, panels for automobiles, etc., one wall of a hollow double-wall structure is required. And a structure in which the other wall is integrated by a concave rib formed from the other wall toward the one wall (JP-A-7-1955).
No. 59).

[0005]

SUMMARY OF THE INVENTION Housing equipment, furniture panels, home appliance housings, office equipment housings,
In the case of a panel of an automobile article or the like, the aesthetic appearance may be asked not only on the front surface but also on the back surface. When high rigidity is required in the case of such a panel, one wall and the other wall are blow-molded to integrate one wall and the other wall of the hollow double-wall structure. Is formed so that a part of the other wall is protruded until it comes into contact with the one wall to form a partition wall (so-called inner rib) integrally connected in the hollow portion (see FIGS. 1 and 3).

By the way, the above-mentioned partition wall is formed by disposing a parison made of a thermoplastic resin between a pair of split molds, clamping the mold, and advancing a slide core provided on the other mold to form one partition wall of the other mold. Part is protruded until it touches one wall, the two walls are welded, the slide core is retracted to the cavity surface of the other mold, and the side surfaces of the protruded walls are welded to each other by blow pressure. The process of forming an integral partition wall between the wall of the other and the other wall is followed, and in the process of forming the protruded wall into the integrated partition wall by the blow pressure, the portion serving as the partition wall becomes the other partition wall. The mold is subjected to blow pressure without being supported by the mold cavity.

[0007] For this reason, due to the geographical variation of the blow pressure and the like, the joint surfaces of the partition walls exhibit a phenomenon of waving along the cavity of the other mold. On the outer surface of the other wall, a wavy line appears at a portion corresponding to the partition wall, and the appearance is impaired.

In view of the above, according to the present invention, a parison made of a thermoplastic resin is arranged between a pair of split molds, the mold is clamped, and a slide core provided on the other mold is advanced to form a part of the other wall. The slide core is made to protrude until it comes into contact with one of the walls and both walls are welded.The slide core is then retracted to a position where it protrudes slightly from the cavity surface of the other mold. And the side surfaces of the protruding walls are welded to each other by blow pressure to form an integral partition wall between one wall and the other wall. In the process of welding the side surfaces of the protruding walls to each other by blow pressure to form an integral partition wall between one wall and the other wall, a portion serving as a partition wall is changed to a tip end of a slide core. With the other mold By supporting it in the cavity, it reliably prevents wavy lines from appearing on the outer surface of the other wall corresponding to the partition wall, and improves the appearance of not only the outer surface of one wall but also the outer surface of the other wall. It is an object of the present invention to provide an excellent hollow double-walled molded product.

Further, the present invention provides a method for manufacturing a hollow double-walled molded product which can reliably obtain a hollow double-walled molded product having excellent appearance not only on the outer surface of one wall but also on the outer surface of the other wall. The aim is to provide a method.

[0010]

In order to achieve the above object, a hollow double-walled molded product according to claim 1 of the present invention is a molded product having a hollow double-walled structure obtained by blow molding a thermoplastic resin. And forming a partition wall that protrudes one wall and the other wall until a part of the other wall comes into contact with the one wall and integrally connects the inside of the hollow portion, and forms an outer surface of the other wall. A groove that is narrower and shallower than the width of the partition wall is formed in a portion corresponding to the partition wall.

According to a second aspect of the present invention, there is provided a hollow double-wall molded product according to the first aspect, wherein a concave 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 the width of the opening end is 1 to 5 mm.

According to a third aspect of the present invention, there is provided the hollow double-walled molded product according to the first or second aspect, wherein the concave groove formed on the outer surface of the other wall at a portion corresponding to the partition wall has a depth equal to the depth thereof. The width is narrowed in the width direction.

According to a fourth aspect of the present invention, there is provided a method for producing a hollow double-walled molded article by blow molding a thermoplastic resin to obtain a molded article having a hollow double-walled structure. Place the parison of thermoplastic resin between the molds and clamp the mold,
By advancing the slide core provided on the other mold, a part of the other wall is protruded until it comes into contact with one wall and both walls are welded, and then the slide core is slightly removed from the cavity surface of the other mold. After retracting to the protruding position,
A pressure fluid is introduced into the parison to form the parison into a shape along the cavity surfaces of the pair of molds, and the side surfaces of the protruded walls are welded to each other by blow pressure to form one wall and the other wall. After forming an integral partition wall between them, the pair of molds is opened to take out the molded product.

[0014]

FIG. 1 is a partially cutaway perspective view showing a hollow double-walled panel according to an embodiment of the present invention, and FIG. 2 is a sectional view of a part thereof. 3 and 4 show a blow molding mode of the hollow double-walled panel according to one embodiment of the present invention, and FIG. 3 is a cross-sectional view showing a process in which a slide core for forming a partition wall is advanced at the time of mold clamping. FIGS. 4A and 4B are cross-sectional views showing a process of retracting the slide core. FIGS. 5, 6 and 7 are cross-sectional views showing another embodiment of the present invention, in which a slide core forming a partition wall is advanced after mold clamping.

In FIGS. 1 and 2, reference numeral 1 denotes a hollow double-walled molded product, and this hollow double-walled molded product 1 is obtained by blow molding a thermoplastic resin. One wall 2 and the other wall 3 constituting the hollow double-walled molded product 1 are integrated by a partition wall 4 formed from the other wall 3 toward the one wall 2. 5 is a hollow part.

The partition wall 4 is an inner rib formed by projecting a part of the other wall 3 of the hollow double-walled molded product 1 until it comes into contact with the one wall 2.
And the other wall 3 in the hollow portion 5, and is a wall integrally provided at the welding portion 7 on the side surface.

A groove 6 is formed in the outer surface of the other wall 3 at a position corresponding to the partition wall 4. This groove 6
It is narrower than the width of the partition wall 4 and extremely shallower than the thickness of the other wall 3, and is formed by the tip of a slide core (described later) involved in forming the partition wall 4.

The groove 6 has a depth of 0.1 to 2 mm.
And the width of the opening end is 1 to 5 mm. When the depth of the concave groove 6 is less than 0.1 mm, the portion of the partition wall 4 which is to be the partition wall 4 has insufficient support for the cavity of the other mold (described later). There may be problems. As will be described later, the width of the groove 6 is 1 m.
m, the integral partition wall 4 by blow pressure
In the process of forming the part, the function of supporting the part to be the partition wall 4 at the tip of the slide core in the cavity of the other mold is insufficient. .

The thermoplastic resin constituting the hollow double-walled molded article 1 according to the present invention may be any one which can be blow-molded, and is a high-density polyethylene resin, a medium-density polyethylene resin, a polypropylene resin, a modified polyphenylene oxide resin. , Polycarbonate resin, polyamide resin, polystyrene resin, ABS resin and the like are preferable.

The hollow double-wall molded product 1 according to the present invention is shown in FIG.
And as shown in FIG. 4, it is manufactured by blow molding a thermoplastic resin. In these figures, a pair of split molds includes one mold 11 and the other mold 12, and one mold 11 connects one wall 2 of the hollow double wall panel 1 to 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.

In order to blow-mold the hollow double-walled molded product 1 using the pair of split dies, a parison 14 is disposed between one die 11 and the other die 12, as shown in FIG. Then, a pair of split molds are clamped. Then, the slide core 13 is advanced, and a part of the part to be the other wall 3 of the parison 14 is protruded until it comes into contact with the part to be the one wall 2 of the parison 14. Weld to the part that will be the wall 2.

Next, as shown in FIG. 4, the slide core 13 is retracted to a position where it protrudes slightly from the cavity surface of the other mold 12, and in this state, the parison 14
When a pressure fluid is introduced into the inside and the pressure inside is increased, the parison 14 is pressed against the cavities of one mold 11 and the other mold 12. The projecting portion of the other wall 3 of the parison 14 forms a welded portion 7 in which both side surfaces are pressed together and welded together to form a partition wall 4. 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.

The blow molded hollow double wall molded product 1 is taken out after cooling a pair of molds.

In the above-mentioned blow molding step, the part to be the partition wall 4 is supported by the protruding tip of the slide core 13 with respect to the cavity of the other mold 12, so that the integral partition wall 4 is formed. Even if blow pressure is applied in the process, the partition wall 4 does not displace along the cavity surface of the other mold 12, and a portion corresponding to the partition wall 4 on the outer surface of the other wall 3 has a wavy shape. Lines can be reliably prevented from appearing. For this reason, the hollow double-walled molded product 1 having excellent appearance not only on the outer surface of the one wall 2 but also on the outer surface of the other wall 3 can be obtained.

FIGS. 5, 6 and 7 show another embodiment of the method for manufacturing a hollow molded product 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 the other aspects are the same as those shown in FIGS. Therefore, the same reference numerals are given to the portions in the same mode, and the description thereof will be omitted.

In the embodiment shown in FIG. 5, the tip of the slide core 13 has a narrowed shape. Thereby, the width of the concave groove 6 can be formed narrow, so that the outer surface of the other wall 2 has good appearance. 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. Then, by doing so, the concave groove 6 formed at a portion corresponding to the partition wall 4 on the outer surface of the other wall 3 is formed so as to be narrower in the depth direction. Release is smooth. Further, in the embodiment shown in FIG. 7, the leading end of the slide core 13 is shaped so that the width thereof is gradually reduced in the leading end direction. Since the portion 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]

According to the present invention, a parison of a thermoplastic resin is disposed between a pair of split molds, the mold is clamped, and a slide core provided on the other mold is advanced, so that one of the other molds is moved forward. Part is protruded until it touches one wall, and both walls are welded.The slide core is then retracted to a position where it protrudes slightly from the cavity surface of the other mold. Are formed along the cavities of the pair of molds, and the side surfaces of the protruding walls are welded to each other by blow pressure to form an integral partition wall between one wall and the other wall. By forming, by welding the side surfaces of the protruding walls by the blow pressure to form an integral partition wall between one wall and the other wall, a portion serving as a partition wall is formed by a slide core. Tip at the other mold By supporting it in the cavity, it reliably prevents wavy lines from appearing on the outer surface of the other wall corresponding to the partition wall, and improves the appearance of not only the outer surface of one wall but also the outer surface of the other wall. An excellent hollow double-walled molded product can be provided.

[Brief description of the drawings]

FIG. 1 is a partially broken perspective view showing a hollow double-walled molded product according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a hollow double-walled molded product according to one embodiment of the present invention.

FIG. 3 is a partial cross-sectional view showing a blow molding mode of the hollow double-walled molded product according to the embodiment of the present invention, showing a step of advancing a slide core forming a partition wall during mold clamping.

FIG. 4 is a partial cross-sectional view showing a blow molding mode of the hollow double-wall molded product according to one embodiment of the present invention, showing a step of retracting the slide core.

FIG. 5 is a partial cross-sectional view showing a blow molding mode of a hollow double-wall molded product according to another embodiment of the present invention, showing a step of retracting a slide core.

FIG. 6 is a partial cross-sectional view showing a blow molding mode of a hollow double-wall molded product according to still another embodiment of the present invention, showing a step of retracting a slide core.

FIG. 7 is a partial cross-sectional view showing a blow molding mode of a hollow double-wall molded product according to still another embodiment of the present invention, showing a step of retracting a 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 Concave groove 7 Welding part 8 Top end surface 11 One mold 12 The other mold 13 Slide core 14 Parison

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B29C 49/70 B29C 49/70 // B29K 101: 12 B29L 24:00

Claims (4)

[Claims] 1. A molded article having a hollow double wall structure obtained by blow molding a thermoplastic resin, wherein one wall and the other wall are protruded until a part of the other wall is in contact with the one wall. And a partition wall integrally connected in the hollow portion is formed, and a groove narrower and shallower than the width of the partition wall is formed in a portion of the outer surface of the other wall corresponding to the partition wall. Hollow double wall molded product. 2. A groove formed in a portion of the outer surface of the other wall corresponding to the partition wall has a depth of 0.1 to 2 mm,
The hollow double-walled molded product according to claim 1, wherein the width of the open end is 1 to 5 mm. 3. The groove according to claim 1, wherein the groove formed on the outer surface of the other wall at a portion corresponding to the partition wall is formed so as to be narrower in a depth direction thereof. Hollow double wall molded product. 4. A method for obtaining a molded article having a hollow double-walled structure by blow molding a thermoplastic resin, wherein a parison of the thermoplastic resin is arranged between a pair of split molds and the mold is clamped. By advancing the slide core provided on the mold, a part of the other wall is protruded until it comes into contact with one wall and both walls are welded, and then the slide core is slightly protruded from the cavity surface of the other mold. After retracting to the position, pressure fluid is introduced into the parison to form the parison into a shape along the cavity surfaces of the pair of molds, and the side surfaces of the protruded walls are welded to each other by blow pressure. A method for manufacturing a hollow double-walled molded product, comprising forming an integral partition wall between one wall and the other wall, and then opening a pair of molds to take out the molded product.