JPH02188226A - Molding method for slender synthetic resin vessel and the same synthetic resin vessel - Google Patents

Abstract

PURPOSE:To prevent the vessel from deterioration of the strength or damage due to a defective groove by forming a thickness reservoir of a swelled state slightly toward an outward direction at least at the center of a bottom face. CONSTITUTION:When a slender synthetic resin vessel is molded by using molds, a flat fusion-bonding part (b) is formed at a slender cylindrical parison (w) by opposite contact positions 8a, 9a of upper and lower molds 9 and 9, and the air is filled in the hollow part s1 of the parison (w). In this case, a thickness reservoir chamber 16 is so operated as to swell and hold the thick wall of the slender cylindrical parison (w) toward the outward direction of the molds and to simultaneously perform a function as the part of a molding surface 10. Accordingly, a slender synthetic resin vessel as a final product is formed with a thickness reservoir (c) of a swelled state slightly toward the outward direction at the center of its bottom face.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for molding an elongated synthetic resin container and to the same synthetic resin container.

(Prior art) Fig. 5 is a schematic diagram for manufacturing a container made of synthetic resin (for example, polyethylene), and 1 is a slender cylindrical parison W (
2 is a molding machine for extrusion molding (with a wall thickness of about 0.6 mm), 2 is a molding device in which a large number of molds 5 are installed around a rotating body 4 that is driven to rotate around a shaft 3, and 6 is a molding machine. This is a guide ring for moving the formed parison W° formed by the device 11t2 to the cutting and finishing step 7.

Each of the molding molds 5 consists of an upper mold 8 and a lower mold 9, as shown in FIG. As shown in FIG. 7, which is a plan view of the lower mold 9, a recess 10 forming the molding surface of the container and recesses 11 and 12 as relief are provided.
0b.

It is formed by a waist portion 10c of the body and a bottom portion 10d.

The mold 5 is driven intermittently in the direction of the arrow f1 shown in FIG. 5, and is set at position PI so as to be arranged relative to the cylindrical balisong W as shown in FIG. At this point, the upper die 8 and the lower die 9 are operated to squeeze the narrow cylindrical parison W with a predetermined force as shown in FIG. Then, both ends of the upper and lower molds are pressed by the opposing parts (protruding parts 8a and 9a) to fuse them into a flat shape, and as shown in FIG. A molded parison W1 is obtained by enclosing gas through a gas enclosing means consisting of pores 15 and the like.

The molded parison W' is connected in a continuous state as the molding device 2 rotates, and is successively released from the mold 5 at another location, and is transferred to a cutting and finishing step 7 to be made into a final product.

(Problems to be Solved by the Invention) In the conventional means described above, when the narrow cylindrical parison W is formed into the molded parison W° in the mold, the protruding portions 8a and 9a of the upper and lower molds are shown in FIG. In this case, a notch is formed along the direction of movement of the narrow cylindrical parison W, and because of this notch, a thin part is formed at the bottom of the synthetic resin container as a product, as shown in FIG. This causes a decrease in the strength of this portion, and therefore, there are problems such as cracks occurring in this portion during filling with beverages, resulting in beverage leakage, or large tears from the core portion.

The present invention has been made to solve the above-mentioned problems, and is intended to provide on the market a synthetic resin container that does not cause a decrease in strength or breakage of the container due to the above-mentioned grooves. be.

(Means for Solving the Problems) The synthetic resin container according to the present invention is formed by molding a narrow cylindrical parison.
It is characterized in that at least the central part of the bottom face is formed with a fleshy part that bulges slightly outward.

The method for molding the container is to blow air into the slender cylindrical parison in the upper and lower molds of the mold, and to compress it between the upper mold and the lower mold, and to form a continuous molded parison by the compressed pressure. This is characterized by forming a flesh chamber in which the parison slightly bulges outward at the contact point where the parisons of the upper and lower molds are pressed.

(Function) During the molding of the narrow cylindrical parison, the flesh wall of the parison is retained in the flesh wall of the parison, so that a flesh wall is formed at a certain portion of the synthetic resin container.

In this way, the inner wall of the fleshy portion is reinforced by increasing the thickness of the portion where the aforementioned notched groove is located, thereby preventing liquid leakage and container breakage.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

Figure 1 shows one side of the mold (upper mold or lower mold) according to the present invention.
FIG. 2 is a side view sectional view showing a section taken along the line A-A in FIG. FIG. 4 is a side view explanatory view showing a part of the mold, (b) is a side view sectional view showing the bottom of the synthetic resin container, and FIG. 4 is a perspective view showing the bottom of the synthetic resin container.

In the present invention, the following improvements are particularly made to the required parts of the mold 5, which is composed of an upper mold 8 and a lower mold 9, which are used in the same manner as before. That is, a certain part of the contact point P that acts to form a flat welded part opening in the narrow cylindrical parison W which is placed relative to the upper and lower molds 8.9 and pressed together is pressed. A notch 16 is provided as a chamber.

Here, the constant portion of the contact point P is defined as a point where, when the narrow cylindrical parison W is compressed between the upper die 8 and the lower die 9, the cross-sectional shape of the parison W is flattened and the walls overlap each other. None, and a certain part of the upper mold 8 and the lower mold 9 that acts to connect and integrate the flesh walls with each other due to the fusion properties of the flesh walls themselves (i.e., the opposing parts shown here as 8a and 9a) However, it is not necessarily limited to one location, but may extend to multiple locations.

In this example, both ends of the slender cylindrical parison W positioned in the upper and lower molds 8.9, namely, the tip of the mouth portion 10a and the bottom portion 10d.
Although the tip corresponds to at least the contact portion P, the tip of the drinking spout 10a may be omitted depending on the case. In the drawings, only the bottom portion 10d will be described.

The shape and dimensions of the notch 16 and its surroundings may vary depending on the specific requirements of the elongated container, but for an example of a cylindrical container with a diameter of 25 mm and a length of 200 mm, ll = 0.4 ~ 0. 5mm, it = 1mmS
l, I=0.7 to 0.9 mm, and the flesh chamber 1
6 has a trapezoidal shape in plan view as shown in FIG.

When molding an elongated synthetic resin container by using the mold 5 described above, the contact portion 8 of each upper and lower mold 8.9
A, 9a forms a flat welded part opening in the narrow cylindrical parison W, and the hollow part sl of the parison W is filled with air. a
), the wall of the slender cylindrical parison W bulges outward from the mold 5 and acts to retain it therein, and at the same time functions as a part of the molding surface 10. The elongated synthetic resin container as shown in Figure 3 (
b) and as shown in FIG. 4, a fleshy part c is formed in the center of the bottom surface which bulges slightly outward. Here, 2 is on the surface of the synthetic resin container and the upper mold 8
This is a linear pattern that appears at the joint between the mold 9 and the lower mold 9.

(Effects of the Invention) According to the present invention carried out as described above, a notched groove (a third
Also in Figure b), since the fleshy portion C is formed and arranged on the front side of the notched groove A, it is possible to avoid a decrease in strength due to the notched groove A.

Therefore, troubles during liquid filling or use such as leakage of the contents of the container from cracks caused by the notched grooves or thick (ruptured) areas around the notched grooves are completely eliminated, and the yield rate is reduced.
This contributes to improvements in quality and quality.

[Brief explanation of the drawing]

Figures 1 to 4 relate to the present invention; Figure 1 is a plan view showing a part of one side of the mold (upper mold or lower mold), and Figure 2 is a plan view of a part of the mold.
FIG. 3 is a side view sectional view showing a cross section taken along line A-A in the figure, and FIG. ) is a side sectional view showing the bottom of the elongated synthetic resin container, and FIG. 4 is a perspective view showing the bottom of the same synthetic resin container. Figures 5 to 11 show conventional examples, Figure 5 is a schematic diagram for manufacturing an elongated synthetic resin container, and Figure 6 is a side view showing a state where the upper mold and lower mold are separated. Fig. 7 is a plan view of the lower mold, Fig. 8 is a perspective view showing the state in which the cylindrical parison is compressed between the upper mold and the lower mold, and Fig. 9 is a cylindrical parison formed between the upper mold and the lower mold. FIG. 10 is a side view cross-sectional view showing a part of the mold, and FIG. 11 is a side view showing the bottom of a synthetic resin container manufactured using this. FIG. 5... Molding mold, 8... Upper mold, 9... Lower mold 16...
・Meat love room (cutout part), A...Meat love part 1, P...
Opposing part, W... Thin cylindrical parison, wl... Molded parison. Patent Applicant Binan Kogyo Co., Ltd. Agent Patent Attorney Hiromoshi Okuma, Hitoshi 1 10b 5: Molding mold 8: A: Flesh feeling part P W″: Molding part, Rison E 9: Lower mold 16: Flesh feeling part Part where two chambers meet W: m cylindrical parison Figure 3

Claims (2)

[Claims] (1) Air is blown into the slender cylindrical parison in the upper and lower molds of the mold, and the upper and lower molds are pressed together, and the compressed pressure creates a continuous molded parison. A method for molding an elongated synthetic resin container, characterized in that the molding process is carried out by forming a filling chamber in which the parison slightly bulges outward at a contact point where the parison of the mold is pressed. (2) A slender synthetic resin container characterized by forming a slender cylindrical parison to form a flesh pocket that bulges slightly outward at least in the center of the bottom surface.