JPS5821372Y2 - Biaxially stretched synthetic resin thin wall bottle - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a thin-walled biaxially stretched plastic bottle suitable for filling, for example, carbonated drinking water or other soft drinks.

Conventionally, glass bottles have been used as this type of bottle, but glass bottles are heavy, which increases transportation costs and is also inconvenient to handle.

In order to eliminate the above-mentioned defects, a Hewei resin bottle whose wall thickness has been made thinner by biaxial stretching is used.

The bottle is made into a thin bottle by biaxial stretching, so it uses less material.
Therefore, it is lightweight, and the mechanical strength of the bottle is high due to biaxial stretching, but as the wall thickness becomes thinner, the rigidity is lost and the bottle becomes flexible, which makes it difficult to hold. Ta.

In order to eliminate this defect, the conventionally used thin-walled plastic bottles made of double-stretched resin have grooves and protrusions formed by molding around the bottle body, which is the thinnest part, to improve elasticity against external pressure. Prevents deformation.

In this way, it seems that the thinning of this type of bottle has been almost reached its limit, but the purpose of this proposal is to make it possible to mold it using even less material. The drawings will be explained.

1 is a thin-walled biaxially stretched resin bottle according to the present invention;
Reference numeral 2 denotes the body, and 3 denotes the shoulder through which a mouth and neck portion 4 having a smaller diameter than the body protrudes.

The synthetic resin material is preferably a saturated polyester resin, but any synthetic resin that can increase the mechanical strength of the bottle by biaxial stretching, such as polypropylene or vinyl chloride, may be used.

The wall thickness of the shoulder portion 3 shall be increased to almost the same thickness as that of the body portion 2, and the shoulder portion is provided with grooves 5 formed by molding.
. . . and the protruding strips 6 .

Reference numeral 7 designates a bottom wall, which protrudes inward into the bottle in a cap-like manner, and a groove 8 is provided in the vertical direction at the lower end of the circumferential wall of the body, as shown in FIG.
. . . and convex strips 9 are alternately formed, or as shown in FIG.
. . . and the protrusions 11 . . . are preferably formed alternately and continuously.

The above bottle may be formed as follows.

That is, as shown in FIG. 3, a tubular intermediate material 12 with a bottom and an opening at the upper end is formed by injection molding or the like, and then placed in a blowing die and biaxially stretched.

In order to make the wall thickness of the bottle shoulder part 3 approximately the same as the wall thickness of the body part, the lower part 14 following the lower end of the mouth and neck part 13 of the intermediate material must be made.
is formed to be thinner than the body portion 15 of the intermediate material,
With the mouth and neck of the intermediate material being clamped by mold clamping, a push-down rod is inserted into the middle material and pushed down.

By pressing down, the lower part of the mouth and neck is thinner than the body, so it is stretched in the longitudinal axis direction more than the body, and then compressed air is blown into the inside of the neck to expand it, so that the body of the bottle is expanded. and shoulder portion 3 are biaxially stretched to approximately the same thickness.

Since the bottom wall of the bottle, like the shoulder part of the bottle, is likely to become thick due to insufficient biaxial stretching, it is preferable that the bottom part 16 of the intermediate material is also formed thinner than the body part.

The concave lines 5 and convex lines 6 on the bottle are formed on the inner wall surface of the cavity of the mold for blow molding. It is formed by blow molding.

The present invention has the above-mentioned structure, and since the wall thickness of the bottle shoulder is made thinner so that it is almost the same as the wall thickness of the body, the bottle can be formed using less combined wood material. As a result, grooves and protrusions formed by molding are formed around the shoulders alternately and continuously, and the cross section is shaped like that of a corrugated sheet, giving it a rib function. Even if the bottle is made thinner, the shoulder part will not become flexible and cause inconvenience in handling the bottle.

Furthermore, since the shoulder portion is reliably biaxially stretched, it has the same strength as the body portion, making it possible to obtain a bottle with excellent strength.

By making the bottle made of saturated polyester resin, the bottle does not leak harmful substances such as solvents and does not generate toxic gas when incinerated after disposal.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of the present bottle, FIG. 2 is a front view of a portion of the bottle shown in another embodiment, and FIG. 3 is a longitudinal sectional view of an intermediate material for forming the present bottle. 1...Bottle, 2...Body, 3...
・Shoulder part, 5... Concave strip, 6... Convex strip, 1
2...Intermediate material.

Claims (1)

[Scope of utility model registration request] In a bottle made of synthetic resin, in which a neck part 4 having a smaller diameter than the body part 2 projects upward through a shoulder part 3, and a wall part other than the neck part is formed thin by biaxial stretching, the shoulder part The wall thickness of the body part 2 is approximately the same as that of the body part 2, and the shoulder part 3 is formed with grooves 5 and 6 by molding.
. . . are arranged around the circumference alternately and continuously to form a cross section of a corrugated plate.