JPH0516216A - Production of plastic bottle - Google Patents

Abstract

PURPOSE:To surely join an accessory such as a grip and a base cup to a bottle main body by the simple constitution of an equipment. CONSTITUTION:In the case of forming a grip by injection to a bottle main body 10 and simultaneously fitting the grip thereto, a backing mold 33 having recessed parts 34 in the abutting parts of the bottle main body and the grip is arranged to the inside of the bottle main body. In the case of forming the grip by injection, the wall face of the bottle main body is pushed into the recessed part 34. Both the bottle main body and the grip are integrated by welding and also the irregularities are engaged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a plastic bottle, and more particularly to a method of attaching accessories such as a handle and a base cup to a bottle body molded by a conventional biaxial stretching method by blow molding.

[0002]

2. Description of the Related Art Since a plastic bottle becomes inconvenient to handle when it is upsized, a bottle with a handle is used as a detergent. Further, since bottles for carbonated drinks and the like require pressure resistance, the bottom of the bottle is formed into a spherical shape and the base cup is attached to the outside thereof.

In such a plastic bottle,
As a procedure for integrating the bottle body and the handle, the parison is blow-molded to mold the bottle body, and the handle is injection-molded to be integrated, or a separately molded bottle body is used for the handle molding die. After mounting inside, a method for injecting a resin for molding a handle into a mold to mold the handle and fusing the bottle body and the handle at the same time, or mounting a separately molded handle in a blow molding mold, When the bottle body is blow-molded, a method is used in which the wall surface of the bottle body wraps the engaging portion of the handle to be integrated.

The base cup is usually formed separately from the bottle body and attached to the bottom of the bottle body with an adhesive or the like.

[0005]

However, in the method of fusion-bonding the handles when the handles are injection-molded, the injection pressure for forming the handles and the temperature of the resin at that time are sufficient to weld them together. In order to obtain adhesiveness, it is necessary to raise the injection temperature as well as the resin temperature. For this reason, the handle mounting portion of the bottle main body is pierced by the injection pressure, or the bottle main body is dented to form a gap between the bottle main body and the cavity, and resin often leaks from the cavity to cause burrs. When burrs are generated in this way, welding between the two becomes insufficient and there is a risk that the handle will fall off during use.

In order to prevent the above-mentioned burrs from occurring, it is generally attempted to reduce the deformation of the bottle body by injecting a gas into the bottle body, but it is impossible to raise the pressure to a level sufficient to withstand the injection pressure. Close to. For this reason, the injection pressure is also reduced, but in this case, the pressure bonding between the bottle body and the handle becomes insufficient, which causes a problem that reliable fusion cannot be achieved.

Further, in the case where the engaging portion of the handle is wrapped with the wall surface of the bottle main body, it is difficult to sufficiently close the engaging portion of the handle to wrap the engaging portion of the bottle, and sufficient attachment strength may not be obtained. . Further, in this method, a large force may be applied to the handle when the bottle body is molded, and the handle may be deformed. Further, since the handle needs to be accurately held in the blow molding mold, the mold becomes complicated. There is also a problem.

On the other hand, when mounting the base cup,
The base cup mounting process after molding the bottle body was complicated.

Therefore, an object of the present invention is to provide a method of manufacturing a plastic bottle which can surely join a bottle body and an accessory with a simple device configuration.

[0010]

In order to achieve the above-mentioned object, a method of manufacturing a plastic bottle according to the present invention is such that a plastic bottle body is attached with an accessory such as a handle or a base cup formed of the same kind of resin. At the same time, a molding die having a cavity for molding the accessory is arranged outside the bottle body, and a receiving mold having a recess at the contact portion between the accessory and the wall surface of the bottle body is provided at the mouth of the bottle body. After inserting and arranging it in the bottle body, the molten resin is injected into the cavity, and the wall surface of the abutting portion of the bottle body is softened by the molten resin, and the wall surface is made to be the concave portion of the receiving mold by injection pressure. The feature is that the accessory and the bottle body are integrated by deforming inside.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in more detail based on the embodiments shown in the drawings.

1 and 2 show a first embodiment of the present invention. FIG. 1 is a sectional view of a mold, and FIG. 2 is a sectional view of a plastic bottle with a handle. 3 and 4 show a second embodiment, FIG. 3 is a sectional view of a main part of a mold, and FIG. 4 is a sectional view of a main part of a plastic bottle with a base cup.

First, as shown in FIG. 2, a plastic bottle with a handle has a bottle body 10 obtained by blow molding a parison made of polyester resin such as polyethylene terephthalate resin, and a resin of the same type as the bottle body 10. Is integrated with the handle 20 obtained by injection molding.

Above the body of the bottle body 10, a handle mounting recess 12 having upper and lower handle mounting portions 11, 11 is provided.
The handle 20 is provided with mounting portions 21 to the bottle body at both upper and lower ends thereof.
In the inner part of 1, there is formed a joining convex part 22 that is inserted into the wall surface of the bottle body 10.

FIG. 1 shows a mold for manufacturing the plastic bottle with a handle. This mold 30 is inserted into the bottle body 10 with a holding recess 31 corresponding to the outer shape of the bottle body 10 that has been preformed, a cavity 32 for forming a handle in which a contact portion with the bottle body 10 is open. The receiving mold 33 is used.

The receiving mold 33 includes the bottle body 10 and the handle 2.
A contact portion with 0, that is, a position corresponding to the joining convex portion 22 has a concave portion 34 for forming the joining convex portion 22, and the external shape thereof is from the mouth portion 13 of the bottle body 10. It is formed so that it can be inserted.

In forming the handle 20, first, the bottle body 10 is placed in the mold 30, and the receiving die 33 is inserted into the bottle body 10 and placed in a predetermined position. This is done by injecting a molten resin into the cavity 32 after press-fitting the fluid.

The molten resin injected into the cavity 32 softens the abutment wall surface of the bottle body 10 at that temperature, and enters the recess 34 while deforming the wall surface of the recess 34 portion by its injection pressure. The joint convex portion 22
Is formed and is fused and integrated with the wall surface of the bottle body.

That is, the molten resin has a melting point higher than that of the resin, for example, 25 in the case of polyethylene terephthalate.
The bottle is brought into contact with the wall surface of the bottle body at 0 to 300 ° C., and the wall surface is melted and deformed by its thermal energy and injection pressure, or is pierced and pushed into the recess 34 of the receiving mold 33 to be integrated.

Since it is received by the receiving mold 33 in this way, not only can the temperature and injection pressure of the molten resin be sufficiently increased to improve the fusion bonding strength, but also the bottle body 10 and the grip 2
By mechanically locking 0 and 0 by concave-convex fitting, the grip attachment strength can be significantly improved as compared with the case where both are joined only by fusion bonding. In addition, since the concavo-convex fitting portion is formed during handle molding, the blow mold for molding the bottle body 10 can be simplified and the mold can be easily manufactured.

The stretching ratio of the joint portion of the bottle body 10 with the handle 20 is set to 1 to 15 times, and the wall thickness is set to 0.
By setting the thickness to 5 mm or more, the attachment strength of both can be further strengthened.

As means for controlling the draw ratio and wall thickness of the handle joint part, there is used a method of forming a bottle shape such that the draw ratio of the part is small, and a part of the mold corresponding to the part is the other part. It can be carried out by a method of lowering the temperature to accelerate the cooling and solidification so as not to stretch, a method of blowing cold air to the portion to quickly solidify, or a combination thereof.

The mold shown in FIG. 3 is for molding the base cup 25 of the plastic bottle with a base cup shown in FIG. This mold has an outer shape corresponding to the bottom shape of the bottle body 15, and an outer mold 36 having a cavity 35 for molding a base cup therein, and a base cup 2.
5 and the bottle main body 15 are provided with a receiving mold 38 having a concave portion 37 at the abutting portion thereof. Then, as shown in FIG. 3, the outer mold 36 and the receiving mold 38 sandwich the bottom of the bottle body, and the molten resin is injected into the cavity 35 in the same manner as described above to mold the base cup 25.

By molding the base cup 25 in this manner, the molten resin pushes the bottom wall surface of the bottle main body into the concave portion 37 of the receiving mold 38, and the joining convex portion 26 is formed and fused and integrated.

The receiving die and the recess formed in the receiving die are
It can be formed into an appropriate shape according to the shape and size of accessories such as the bottle body, the handle, and the base cup, the required strength, and the number of recesses can be set arbitrarily. In addition, the accessory and bottle body should be integrated by injecting the molten resin for fusion bonding the accessories such as the handle and the base cup, which are separately molded, to the wall surface of the bottle body. You can

[0026]

As described above, according to the method of manufacturing a plastic bottle of the present invention, when attaching accessories such as a handle and a base cup to the bottle body, a receiving mold having a concave portion at the contact portion with the accessory is used. It is placed inside the bottle body, and when the accessories are injection-molded, the wall surface of the bottle body is pushed into the recess, and they are integrated by fusion and have a concave and convex fitting. Can be improved.

Furthermore, since the concave-convex fitting portion is formed during molding of the accessory, it is not necessary to form a concave portion or a convex portion during blow molding in the bottle body, and the mold can be easily manufactured. Further, the base cup can be attached at the same time as the injection molding, so that the process can be simplified.

[Brief description of drawings]

FIG. 1 is a sectional view of a handle forming die showing a first embodiment of the present invention.

FIG. 2 is a sectional view of an essential part of the plastic bottle with a handle.

FIG. 3 is a cross-sectional view of a base cup molding die showing a second embodiment.

FIG. 4 is a sectional view of a main part of a plastic bottle with a base cup.

[Explanation of symbols]

Reference numeral 10 ... Bottle body 11 ... Handle mounting portion 12 ... Handle mounting concave portion 20 ... Handle 21 ... Bottle body mounting portion 22, 26 ... Joining convex portion 25 ... Base cup 30 ... Mold 31 ... Holding concave portion 32, 35 ...
Cavities 33, 38 ... Receiving molds 34, 37 ... Recesses
36 ... Outer mold

Claims (1)

What is claimed is: 1. When attaching accessories such as a handle and a base cup formed of the same kind of resin to a plastic bottle body, the cavity for molding the accessory is provided outside the bottle body. While placing a molding die having a, the receiving mold having a concave portion in the contact portion between the accessory and the bottle body wall surface is inserted into the bottle body from the bottle body mouth portion and placed, and then in the cavity. Injecting molten resin to soften the wall surface of the contact portion of the bottle body by the molten resin, and transforming the wall surface into the recess of the receiving mold by injection pressure to integrate the accessory and the bottle body. A method for manufacturing a plastic bottle, characterized by: