JPH1142697A - Method and apparatus for blow molding, and blow molded container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply obtain a container without retaining content liquid by sandwiching a parison between right and left molds, blow molding it, raising a mold of a bottom before resin is solidified, and embedding a gap of a peripheral edge of a bottom in a molded container with the resin. SOLUTION: A parison 4 is extruded, surrounded by left and right molds 1, 2. Further, split bottom molds 3 are disposed at lower parts of the molds 1, 2, and the parison 4 is sandwiched therebetween. When the parison 4 is sandwiched between the molds 3, a lower end of the parison 4 is simultaneously cut, its bottom is connected to be sealed. Then, compressed air is blown from an air nozzle to mold it in a shape of a container. When the shape of the container is decided to certain degree, the bottom molds are raised by a driving means, thereby raising its bottom. At this time, to eliminate formation of a gap at a peripheral edge 5c of the bottom, the molds 3 are raised before the parison is solidified, and the edge 5c is embedded with resin. Thus, when no gap is formed, content liquid is not retained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for blow molding a plastic container and a container obtained by the method and apparatus for blow molding a plastic container, and more particularly to a container used for a pump and a liquid fragrance used for a suction core. It is related to the shape of the bottom of the container.

[0002]

2. Description of the Related Art Conventionally, pumps are often used for containers such as shampoos and rinses. Such a container or a container used for a liquid fragrance is molded by blow molding or the like. In blow molding, usually, the left and right dies (10) in FIG. 9 are used.
As shown in (11), the center of the bottom of the container is slightly raised to form.

[0003]

Therefore, in these containers, as shown in FIG. 7 and FIG.
There is a problem that the content liquid remains on the peripheral portion of the bottom portion, and it is inconvenient to use up the entire liquid. In particular, in the case of the container (12) used for a liquid fragrance, as shown in FIG. 7, the suction wick (13) is vertically provided toward the center of the bottom of the container, so that the content liquid is supplied to the peripheral portion of the bottom. It is difficult to completely use up the remaining liquid remaining in (12a), and if there is a residual liquid that is not used up, the consumer is less likely to buy a new one and often leaves the residual liquid for a long period of time.

In the case of a container (14) using a pump, as shown in FIG. 8, the suction nozzle (1) of the pump is used.
5) may be bent so as to be close to the bottom peripheral portion (14a) so that the whole can be sucked up. However, it is easy to mechanically insert the bent nozzle (15) into the container. Instead, a proper device was required, and there was a problem in cost. Therefore, an object of the present invention is to provide a container which can prevent the residual liquid from being present at the peripheral portion of the bottom in the container and can solve the above-mentioned problems, a blow molding method for molding the container, and a device therefor. It is assumed that.

[0005]

In order to achieve the above object, the present invention first provides the following blow molding method. In other words, the parison formed by extruding the resin into a cylindrical shape is sandwiched between the left and right molds from both sides, and air is blown into the parison to perform blow molding. Raise the bottom mold that is located, fill the gap around the bottom edge in the molding container with resin, and when the resin hardens, lower the bottom mold to its original position and open the left and right molds The blow molding method is characterized in that the molded container is taken out by blowing.

The following blow molding apparatus is provided as an apparatus necessary for carrying out such a method. That is, a parison supply nozzle that extrudes resin into a cylindrical shape to form a parison, left and right molds that sandwich the parison from both sides, air nozzles that eject air into the parison, and a lower part of the left and right molds. And a bottom mold configured to be movable up and down. In this blow molding apparatus, the upper surface of the bottom mold is inclined toward the center, and a recess is formed at the center of the upper surface.

Another object of the present invention is to provide the following blow-molded container obtained by the above method and apparatus. That is, in the molded container, a blow molded container characterized in that the gap at the bottom edge of the raised bottom is filled with resin, and further desirably, in the molded container, the bottom upper surface is inclined toward the center. And a recess formed in the center of the upper surface thereof.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below based on examples shown in the drawings. The shape of the container in this embodiment is assumed to be a container using a pump. FIG. 1 is a schematic perspective view of a mold according to the present invention, and FIG. 2 is a side sectional view of a blow molded pump container according to the present invention. FIGS. 3 to 6 are process diagrams illustrating the blow molding method of the present invention. The present invention relates to blow molding of a plastic container, particularly to the shape of the bottom of the container, and a bottom mold for molding the bottom of the container is provided separately from the left and right molds for molding the body of the container. It is characterized by the following.

As shown in FIG. 1, the molding die used in the present invention comprises left and right dies (1) and (2) for mainly molding a mouth portion and a trunk portion of a container, and a bottom portion. Mold at bottom (3)
And divided into Inner surface part (1) of left and right molds (1) and (2)
a) (2a) includes a container (5) using a pump shown in FIG.
A cavity conforming to the outer shape of the container (5) is formed so that the shape of the container (5) is obtained, and the upper surface (3a) of the bottom mold (3) is inclined obliquely downward toward the center of the upper surface. A downwardly inclined surface is formed, and a concave portion (3b) having a circular shape in plan view is formed at the center of the upper surface. The bottom mold (3) is configured to be dividable into two so that the parison (4) can be sandwiched together with the left and right molds (1) and (2), and is configured to be movable up and down by any driving means. Have been.

For example, in the case of a container (5) using a pump as shown in FIG. 2, the diameter of the concave portion (3b) of the bottom mold (3) is larger than the diameter of the suction nozzle (6) of the pump. or,
In the case of a container used for a liquid fragrance, it is formed to be slightly larger than the diameter of the suction core, and it is preferable that the diameter is at most about twice the diameter. This is reliably formed by the concave portion (3b) of the bottom mold (3) even when there is a slight displacement when the straight suction nozzle (6) or the suction core is attached to the container. This is because the nozzle (6) and the core are fitted into the concave portion (5b) of the container bottom.

In the meantime, a concave portion (5
Although the shape of b) is circular in plan view, the shape of the concave portion (5b) is not limited to this. For example, if the shape is such that the nozzle (6) and the core can be fitted, a square shape in plan view is used. There may be. Further, as shown in FIG. 2, the depth of the concave portion (5b) at the bottom of the container is set so that the liquid can be easily sucked even if the nozzle is slightly cut off at the tip. It is desirable to form it with a length of notched or more, and it is usually preferable to have a depth of about 5 mm. Also, by forming the concave portion (5b), the center of the lower surface of the container bottom protrudes downward, but the protruding height of this portion raises the bottom in consideration of the stability of the container. Therefore, it is necessary to set the outer peripheral end (5d) formed below to a projecting height or less.

Next, the process of blow molding the container according to the present invention using the left and right dies (1) and (2) and the bottom die (3) will be described with reference to FIGS. (7) is a parison supply nozzle connected to a parison supply device (not shown) so that a thermoplastic resin such as polyethylene or polypropylene is extruded downward in a cylindrical shape to form a parison (4). It has become. The nozzle (7) can be moved up and down by any driving means. When the parison (4) is extruded by a predetermined length from the parison supply nozzle (7), as shown in FIG. 3, the parison (4) is sandwiched from both left and right sides so as to be surrounded by left and right molds (1) and (2). The mold (3) is divided into two parts,
The left and right dies (1) and (2) are respectively located below the left and right dies (1) and (2), which are moved by an arbitrary driving means, and are integrally moved to sandwich the parison (4). . At the same time as the bottom mold (3) sandwiches the parison (4), the lower end of the parison (4) is cut and the bottom is joined and sealed.

When the left and right molds (1) and (2) and the bottom mold (3) sandwich the parison (4), the air nozzle connected to the compressed air supply device (not shown) as shown in FIG. The parison (4) descends from above and enters the parison (4), and compressed air is blown out from the air nozzle (8).
Are pressed toward the inner surface portions (1a) and (2a) of the mold to form a container formed by a cavity in a mold. The upper end of the parison (4) is cut and aligned by a cutter (not shown) at the tip of a blow head (9) provided so as to surround the air nozzle (8). Similarly to the parison supply nozzle (7), the air nozzle (8) is configured to be able to move up and down by any driving means. Further, the parison (4) is gradually cooled by contacting the mold, and is gradually fixed in the shape of the container used by the pump.

When the shapes of the mouth portion and the trunk portion of the container are determined to some extent, as shown in FIG. 5, the bottom mold (3) is raised by an arbitrary driving means to raise the bottom of the container. This is a process equivalent to bottom-up molding, which forms an outer peripheral end at the bottom and stabilizes the container horizontally, as in ordinary blow molding, but in the present invention, at this time, inside the container, In order to prevent a gap from being formed at the boundary between the body part and the bottom part of the container, that is, at the peripheral part (5c) of the bottom part shown in FIG. 2, the bottom mold (3) is used while the resin (parison) is not completely solidified. Is raised, and the peripheral portion (5c) is filled with resin. By filling this area with resin so as not to create gaps, the content liquid does not remain as in the past,
It can be easily used up to the last liquid. The height at which the bottom is raised, that is, the height at which the bottom mold (3) is raised is such that the peripheral portion (5c) of the bottom can be filled with resin so that no gap is formed, and the recess ( 5b), the outer peripheral end of the bottom portion (5
The height must be such that d) protrudes, and although it depends on the container to be molded, it is usually preferable to increase the depth by about 10 mm with respect to the depth of about 5 mm.

After the outer shape of the container is finally formed, after cooling the resin (parison), the bottom mold (3) is lowered to the original position as shown in FIG. (1) Open the mold (2) and the bottom mold (3) to the left and right, and take out the molded container from the mold. The mold from which the container has been taken out again sandwiches the next parison, and the above-described steps are repeated to form the next container.

The pumped container (5) thus produced is shown in FIG. According to such a container, there is no gap in the peripheral portion (5c) of the bottom, and the bottom upper surface (5c)
Since a) is inclined downward toward the center, all the remaining content liquid is collected and stored in the concave portion (5b) at the center of the bottom, and may remain in the gap at the peripheral edge of the bottom as in the related art. Absent. Accordingly, in the case of the pump-using container (5), the suction nozzle (6) of the pump may be straight, which facilitates installation on a machine and allows the last liquid to be used up. And in the container used for a liquid fragrance, a wick can suck up to the last liquid.

As described above, according to the present invention, in a container for containing a liquid, the peripheral portion of the bottom in the container is filled with the resin so as not to form a gap, and the upper surface of the container bottom is directed toward the center. Since it is inclined and formed with a concave part in the center part of the upper surface, the remaining content liquid is all collected in the concave part in the center of the bottom part, and in the case of a container using a pump, a suction nozzle is used for liquid fragrance. In the case of a container, the suction wick fits into the recess,
The content liquid can be easily used up to the end, and the liquid does not remain as in the related art.

Conventionally, when the mold is opened on both sides and the container is taken out, the amount of the bottom raised is very small so that the outer peripheral end of the raised bottom does not interfere with the mold as much as possible. According to the method, since the bottom mold is lowered to the original position and then the mold is opened to both sides, the amount of bottom rise is not restricted, and the bottom is raised until a desired projection height of the outer peripheral end is obtained. It is possible to do. Needless to say, the shape of the container according to the present invention is not limited to those shown in the drawings, and the shape of the bottom upper surface and the shape of the concave portion can be appropriately changed in design within the spirit of the present invention. is there.

[0019]

According to the present invention, it is possible to fill the gap between the raised bottom periphery in the molding container with the resin, and it is possible to easily mold a container in which the content liquid does not remain. In addition, if the bottom upper surface is inclined toward the center and a concave portion is formed in the center of the upper surface, all the liquid remaining in the container will be collected in the concave portion, and the pump-use container or It is particularly suitable as a container used for liquid fragrances. That is, since the suction nozzle and the suction core are fitted into the recesses, the content liquid can be easily used up to the end.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a mold of the present invention.

FIG. 2 is a side sectional view of a container using a pump according to the present invention.

FIG. 3 is a process diagram illustrating a blow molding method of the present invention.

FIG. 4 is a process diagram illustrating a blow molding method of the present invention.

FIG. 5 is a process diagram illustrating a blow molding method of the present invention.

FIG. 6 is a process diagram illustrating a blow molding method of the present invention.

FIG. 7 is a side sectional view of a container used for a conventional liquid fragrance.

FIG. 8 is a side sectional view of a conventional container using a pump.

FIG. 9 is a schematic side sectional view of a conventional mold.

[Explanation of symbols]

 Reference Signs List 1 left mold 2 right mold 3 bottom mold 4 parison 5 container using pump 6 suction nozzle 7 parison supply nozzle 8 air nozzle 9 blow head

Claims (5)

[Claims] 1. A parison formed by extruding a resin into a cylindrical shape is sandwiched between left and right molds from both sides, and air is blown into the parison to perform blow molding. Raise the bottom mold located at the bottom of the mold, fill the gap around the bottom edge in the molding container with resin, and when the resin has hardened, lower the bottom mold to its original position, and A blow molding method characterized by opening a mold and taking out a molding container. 2. A parison supply nozzle for extruding a resin into a cylindrical shape to form a parison, left and right molds for sandwiching the parison from both sides, air nozzles for blowing air into the parison, and lower portions of the left and right molds. And a bottom mold configured to be movable up and down. 3. The blow molding apparatus according to claim 2, wherein an upper surface of the bottom mold is inclined toward a center, and a concave portion is formed in a center of the upper surface. 4. A blow-molded container, characterized in that a gap between the raised bottom edge and the inside of the molded container is filled with a resin. 5. The blow-molded container according to claim 4, wherein, in the molded container, a bottom upper surface is formed so as to be inclined toward the center, and a concave portion is formed at the center of the upper surface.