JPS6134270Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flexible plastic container with an invertable bottom, and more particularly to the shape of the bottom.

When a flexible plastic container is filled with cosmetic liquid, sealed tightly, and stored for a long period of time, depending on the nature of the content, the content or gas vaporized from the content may permeate the walls of the container or cause damage to the inside of the container. air or oxygen in the headspace may be absorbed into the contents;
In such a case, the total amount of liquid and gas in the container (hereinafter referred to as total storage amount) decreases. Since the body of a flexible plastic container is easily deformed, the body deforms when the total amount accommodated in the upper part of the container is reduced. For example, in the case of a cylindrical body, the middle portion in the axial direction is more concave than both end portions. This is an undesirable phenomenon.

It is known that in order to prevent this deformation of the body, the bottom of the container can be shaped and have a wall thickness that is easier to deform than the body. However, in a container with a structure in which the body and the bottom are separate, the bottom is designed not to deform, so an example of a shape of the bottom that can be deformed and reversed is when the body and the bottom are integrally molded. A plastic container is shown (Figure 1). In the figure, reference numeral 1 denotes a body of a flexible plastic container having an opening at one end, and a bottom 3 at the other end 2, which is continuous with and is integral with the body. The bottom part 3 consists of a peripheral wall 4 and a thin dome wall 5 continuous with one end of the peripheral wall 4.

When this container is filled with liquid and pressurized, the center portion 5' of the thin dome wall 5 is inverted (second
figure). However, when the inside of the container is depressurized, the dome wall 5, which has been once inverted, is again inverted inward, returning to its original shape and becoming close to the state shown in Figure 1. In comparison, since the internal volume is reduced, changes in the pressure inside the container are alleviated, and as a result,
The occurrence of dents in the body is prevented.

However, this bottom part 3 must be able to restore itself to its original dome shape protruding inward after the dome wall 5 is turned outward. Therefore, the peripheral wall 4 and the inverted dome wall must be connected by a curved surface 6 as shown in the second figure. Therefore, the elastic force that causes the curved surface portion 6 to return to its original shape is:
It must be sufficient to restore the inverted part to its original dome shape. The depth H of the dome wall must therefore not be deep, but rather very shallow. As a result, the difference in internal volume before and after inversion becomes extremely small. For example, in a container with a diameter of about 30 mm and a height of about 80 mm, the depth H is about 3 mm. In a cylindrical container where the diameter of the body is approximately 1/2 of the height of the container, it is difficult for the difference in internal volume to exceed 1% of the internal volume before inversion.

By the way, in the case of liquids such as cosmetics, the total amount held in the container after filling may decrease by 2% or more.
Even if a container with the above-mentioned bottom is applied to a container for such a liquid, dents in the body cannot be avoided.

The purpose of the present invention is to provide a plastic container that can avoid deformation of the container body even when filled with a liquid that reduces the total volume of the container by about 4%. A plastic container consisting of a body and a reversible bottom attached to the lower end of the body, the bottom having a vertical wall that can be fitted inside the lower end of the body, and a vertical wall that extends from the top of the vertical wall. It is composed of an annular wall that extends inward in the diametrical direction of the body, and a dome wall that is continuous with the annular wall and is convex inward of the container, the vertical peripheral wall and the annular wall, and the annular wall and the dome. A plastic container with an invertible bottom is obtained, characterized in that each connecting part of the wall is thin, and the vertical peripheral wall is joined at its lower end to the lower end of the body.

An example of the present invention will be described below based on the drawings.

Figure 3 is a front sectional view (partially cut away) of a specific example of the present invention, Figure 4 is a sectional view showing the bottom of the container in Figure 3 being inverted by blowing pressurized air, and Figure 5 is FIG. 2 is a cross-sectional view showing the state of the bottom when blowing pressurized air is stopped.

In these drawings, 11 has a mouth portion 7 on one end side.
A flexible plastic container body 13 is formed separately from the body and is fitted inside the lower end portion 12 of the body. The bottom portion 13 has a vertical peripheral wall 1 that can be fitted into the body portion.
4, an annular wall 15 extending diametrically inward from the upper end of the standing peripheral wall, and an annular wall 15 that is continuous with the inner end of the annular wall 15, is surrounded by the annular wall 15, and is convex inward of the container. It consists of a dome wall 16 and a standing peripheral wall 14.
The connecting portion A between the annular wall 15 and the annular wall 15 and the connecting portion B between the annular wall 15 and the dome wall 16 are each thin. The lower end portion of the standing peripheral wall 14 is the lower end portion 17 of the body portion 11.
is joined to. The joining is performed by hot melt pressure bonding or other appropriate methods.

The dimensions of the body of the container in this specific example are: diameter d3cm;
Height L is about 8 cm, internal volume is about 50 c.c., wall thickness is T 0.3 mm, and the wall thickness at the bottom is 1 mm except for connecting parts A and B.
However, the connecting parts A and B are 0.5 at the center.
mm thick, and both sides of the central part gradually increase their wall thickness. The width W of the annular wall is 3 mm, and the dome depth h is 6 mm.

Prior to filling the container with liquid, pressurized air (1 kg/cm ² ) is blown into the container through the spout 8 at the mouth of the container.
Then, the bottom part 13 is bent at the thin wall of the connecting part A, and the annular wall 15 is inclined downward, and this inclination pulls the dome wall 16 toward its periphery, and the third The dome wall is shallower than the dome wall in the figure, and the reversal resistance is reduced.
Invert (Figure 4). For this reversal, both connecting parts A,
The deformation of B makes a large contribution. The peripheral portion 18 of the dome wall 16', which has been inverted at this time, has a slightly flat shape.

Next, when the blowing of pressurized air is stopped, the bottom 1
6' is in the state shown in FIG. 5 due to the elasticity of the plastic material. This is a form in which only the dome wall 16 is inverted in the third illustrated state. That is, the annular wall 1
5 returns to its original flat state, and the dome wall 16
Inverted dome wall 1 without said peripheral portion 18
It becomes 6″.

When the container bottom 13 is in the state shown in the fifth figure, the container is filled with liquid (45 c.c.) and the container is sealed. Next, a pressing force is applied to the bottom part 13 from the outside in the axial direction of the container, and the inverted dome wall 1
6'' back into the upward facing dome wall 16 shown in FIG.

The difference between the internal volume (52 c.c.) of this example container in the state shown in Fig. 5 and the internal volume (50 c.c.) when the dome wall is returned to the state shown in Fig. 3 after sealing is approximately It was 2.0cc. This 2.0cc is 4% of the total storage capacity of 50cc.

This container was stored for a long period of time, and it was confirmed that no dents occurred in the body.

According to the present invention, the container is composed of a bottom circumferential wall, an annular wall, and a dome wall, and the connection parts A and B of these three walls are formed thin, so that when pressure is applied to the bottom, the annular wall first closes. Starting from the connecting part A, it easily slopes downward, and along with this, the connecting part B
deformation and elongation and flattening of the dome wall 16 to facilitate inversion of the dome wall. Therefore, the depth of the dome wall has to be reduced compared to the conventional configuration, as shown in Figure 1, where the dome wall is directly connected to the standing wall, making it difficult to turn over, and therefore the dome wall depth has to be made shallower. (According to the above example, H is 6 mm compared to H of 3 mm.)
mm, it is actually possible to deepen the depth by 100%). Since the bottom can be easily inverted even if the dome wall depth is deep, the difference in the internal volume of the container before and after inversion, and therefore the increase in the internal volume of the container, is greater than that of a container with a conventionally configured bottom. This makes it possible to obtain a container that can withstand practical use even when filled with liquids that have a large difference in total capacity.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing an example of the shape of the reversible bottom of a plastic container with an integrated body and bottom, Figure 2 is a cross-sectional view showing the inverted state of the bottom caused by filling and pressurizing the content liquid, and Figure 3 is the present invention. A front sectional view (partially cut away) of one example, Figure 4 is a sectional view showing the inverted state of the bottom caused by blowing pressurized air, and Figure 5 shows the state of the bottom when blowing pressurized air is stopped. Cross-sectional view. 11... Trunk, 13... Bottom, 14... Standing peripheral wall, 15... Annular wall, 16... Dome wall, A, B
...Connection part.

Claims (1)

[Claims for Utility Model Registration] A plastic container consisting of a body with a mouth and a reversible bottom attached to the lower end of the body, the bottom being able to be fitted inside the lower end of the body. an annular wall extending inward in the diametrical direction of the body from the upper end of the standing circumferential wall; and a dome wall that is continuous with the annular wall and convex inward of the container; A plastic container with a reversible bottom, characterized in that the annular wall and the connecting portions of the annular wall and the dome wall are thin, and the lower end of the standing peripheral wall is joined to the lower end of the body. .