JP7504538B2 - Plastic flat container - Google Patents

Description

The present invention relates to a flat container made of synthetic resin.

Conventionally, a synthetic resin flat container used to store various contents such as food and cosmetics has been known that has a cylindrical mouth, a shoulder connected to the mouth, a body connected to the shoulder, and a bottom connected to the body, and the body has a flat shape with a width in the left-right direction greater than its thickness in the front-to-back direction and is squeezable.

For example, Patent Document 1 describes a flat container made of synthetic resin with a flat shape, the body of which has a front wall that is curved so that the center in the left-right direction protrudes forward relative to the axis, a back wall that is curved so that the center in the left-right direction protrudes backward relative to the axis and faces the front wall across the axis, and a pair of bent parts that form the boundary between the front wall and the back wall at both left-right ends.

With a synthetic resin flat container of this construction, the body can be easily squeezed in the front-to-back direction, so even if the contents are relatively viscous, the contents can be easily pushed out of the mouth by squeezing the body and used.

JP 2019-081559 A

However, in the above-mentioned conventional synthetic resin flat containers, the body has a pair of bent parts that extend linearly parallel to the axis. Therefore, when the front and rear walls deform so as to expand in the front-to-rear direction due to an increase in internal pressure, for example when hot contents are filled during hot filling and the heat and weight of the contents are added, a force is applied to the pair of bent parts that tends to constrict them toward the inside of the container, causing plastic deformation so that the pair of bent parts bend toward the inside of the container, which can cause creases.

The present invention aims to solve these problems, and its objective is to provide a flat container made of synthetic resin that can prevent wrinkles from forming at a pair of bent portions due to an increase in internal pressure.

The flat container made of synthetic resin of the present invention is a flat container made of synthetic resin having a cylindrical mouth, a shoulder portion connected to the mouth, a body portion connected at an upper end to the shoulder portion, and a bottom portion connected to the lower end of the body portion, wherein the body portion has a flat shape whose width in the left-right direction is greater than its thickness in the front-to-back direction and is configured to be squeezable, and is characterized in that the body portion has a front wall curved so that its left-right central portion protrudes forward relative to the axis, a rear wall curved so that its left-right central portion protrudes rearward relative to the axis and faces the front wall across the axis, and a pair of bent portions that form boundaries between the front wall and the rear wall at both left-right ends, each of the pair of bent portions having at least a curved portion that is concavely curved toward the axis when viewed from the front , and the bottom portion has a semicircular shape that is convex downward when viewed from the front.

In the synthetic resin flat container of the present invention, in the above configuration, it is preferable that the depth of curvature of the curved portion is 0.10 mm or more and 5.00 mm or less.

In the synthetic resin flat container of the present invention, in the above configuration, it is preferable that the curved depth of the curved portion is 0.50 mm or more and 5.00 mm or less.

In the synthetic resin flat container of the present invention, in the above configuration, it is preferable that the upper end of the curved portion is within 1/4 of the range from the upper end of the body, and the lower end of the curved portion is within 1/4 of the range from the lower end of the body.

In the synthetic resin flat container of the present invention, in the above configuration, it is preferable that the upper end of the curved portion coincides with the upper end of the body.

In the synthetic resin flat container of the present invention, in the above configuration, it is preferable that the cross sections of the front wall and the rear wall in the portions where the curved portions are not provided are each arc-shaped.

In the synthetic resin flat container of the present invention, in the above configuration, it is preferable that the body has a shape that is symmetrical front-to-back and left-to-right.

In the above configuration, the synthetic resin flat container of the present invention is preferably formed by extrusion blow molding.

The present invention provides a flat container made of synthetic resin that can prevent wrinkles from forming at a pair of bent portions due to an increase in internal pressure.

1 is a front view of a flat synthetic resin container according to one embodiment of the present invention. FIG. 2 is a side view of the synthetic resin flat container shown in FIG. 1 . FIG. 2 is a plan view of the synthetic resin flat container shown in FIG. 1 . FIG. 2 is a bottom view of the synthetic resin flat container shown in FIG. 1 . 2 is a cross-sectional view taken along line AA in FIG. 1. FIG. 2 is a front view of the synthetic resin flat container shown in FIG. 1 in a state where the contents are hot-filled. 7 is a cross-sectional view taken along line BB in FIG. 6.

The present invention will now be described in more detail with reference to the drawings.

As shown in FIG. 1, the synthetic resin flat container 1 of this embodiment (hereinafter also referred to as "container 1") has a cylindrical mouth 10, a shoulder 20 connected to the mouth 10, a body 30 connected to the shoulder 20, and a bottom 40 connected to the body 30. The synthetic resin flat container 1 is a blow molded product formed by extrusion blow molding (EBM: Extrusion Blow Molding) a parison of a synthetic resin material, and the mouth 10, shoulder 20, body 30, and bottom 40 are integrated.

In this specification, the direction along the axis O of the container 1 is defined as the up-down direction, the side where the mouth 10 is located relative to the bottom 40 is defined as the upper side, and the opposite side is defined as the lower side.

As shown in FIG. 3, the mouth 10 is cylindrical and has an external thread 11 integrally formed on its outer periphery, to which a cap or the like can be attached. The inside of the container 1 is a storage space S for the contents, and the tip opening 12 of the mouth 10 is an outlet for the contents. In addition, an annular neck ring 13 is integrally formed on the mouth 10 closer to the shoulder 20 than the external thread 11.

The mouth portion 10 is not limited to a cylindrical shape, and may be, for example, a rectangular or elliptical cylindrical shape, as long as it is tubular. A cap or the like may be attached to the mouth portion 10 by tapping it.

As shown in Figs. 1 to 3, the shoulder portion 20 is integrally connected at its upper end to the lower end of the mouth portion 10, has a shape that gradually widens downward, and is integrally connected at its lower end to the upper end of the body portion 30. In this embodiment, as shown in Fig. 1, the shoulder portion 20 has a semicircular shape that is convex upward when viewed from the front, and the cross-sectional shape at each position in the vertical direction is a flat shape whose left-right width is greater than its front-to-back thickness.

As shown in Figures 1 to 5, the body 30 is cylindrical and extends in a direction along the axis O of the container 1, and has a flattened shape with a width W in the left-right direction greater than its thickness T in the front-to-rear direction, and is connected integrally to the lower end of the shoulder 20 at its upper end. The width W in the left-right direction of the body 30 is the same at the upper and lower ends. The body 30 is flexible, and is configured so that it can be squeezed in the front-to-rear direction (short axis direction) when dispensing the contents.

More specifically, the body 30 has a front wall 31 and a rear wall 32 that are arranged facing each other in the front-rear direction across the axis O of the container 1. The front wall 31 has a curved shape such that the approximate center in the left-right direction (the direction of width W) protrudes forward relative to the axis O, and the rear wall 32 has a curved shape such that the approximate center in the left-right direction protrudes backward relative to the axis O.

The body 30 also has a pair of left and right bent portions 33 that form the boundaries between the front wall 31 and the rear wall 32 at both left and right ends. Each of the pair of bent portions 33 extends straight in the vertical direction when viewed from the side as shown in FIG. 2. In this embodiment, the pair of bent portions 33 are provided along the parting line of the mold when the container 1 is formed by extrusion blow molding.

The pair of bent portions 33 have a cross-sectional shape that is curved in an arc shape, and the radius of the inner surface can be, for example, about 1.0 mm.

The body 30 has a pair of bent portions 33 that form the boundary between the front wall 31 and the rear wall 32, so that the front wall 31 and the rear wall 32 can be easily crushed and squeezed in the front-rear direction using the pair of bent portions 33 as fulcrums.

In this embodiment, the front wall 31 and the rear wall 32 are symmetrical with respect to the front and rear, and the bent portions 33 on both the left and right sides are also symmetrical with respect to the left and right. In other words, the body 30 is symmetrical with respect to the front and rear, and also symmetrical with respect to the left and right.

As shown in Figures 1, 2 and 4, the bottom 40 is integrally connected to the lower end of the body 30 at its upper end and closes the lower end of the body 30. The bottom 40 has a shape that gradually narrows in width downward. In this embodiment, as shown in Figure 1, the bottom 40 has a semicircular shape that is convex downward when viewed from the front, and the cross-sectional shape at each position in the vertical direction is a flat shape whose width in the left-right direction is greater than its thickness in the front-to-rear direction. In this way, in the container 1 of this embodiment, the bottom 40 that closes the lower end of the body 30 is curved so that the entire bottom 40 bulges downward and has a flat shape, so that the body 30 can be squeezed more easily in the front-to-rear direction compared to a container in which the lower end of the body is closed by a bottom perpendicular to the axis O.

As shown in Figs. 1 and 5, the pair of bent portions 33 each have a curved portion 33a that is curved concavely toward the axis O. The pair of curved portions 33a are curved in an approximately arc shape such that the curve depth D is deepest at the vertical center position between the upper end 33a1 and the lower end 33a2, and the curve depth gradually becomes shallower from that position upward and downward. The pair of bent portions 33 on the left and right sides of the body 30 have a pair of curved portions 33a that curve toward each other, so that the vertical center portion has a narrow shape.

The curved portion 33a is not limited to the generally arcuate shape described above, and may be configured to have a linear portion extending parallel to the axis O at the deepest portion of the curve depth D.

For example, when the pressure (internal pressure) inside the container 1 increases due to hot-filling of the contents inside the storage space S of the container 1, or due to an increase in the temperature of the external environment or the filling of the container with contents that generate gas, and the front wall 31 and the rear wall 32 are deformed so as to expand in the front-rear direction, a force is applied to the pair of bent portions 33 that tends to constrict them toward the inside of the container. At this time, in the container 1 of this embodiment, since the pair of bent portions 33 are each provided with a curved portion 33a, the force is applied in a distributed manner to the entire curved portion 33a, and as a result, as shown in Figures 6 and 7, the pair of bent portions 33 can smoothly deform in response to the force so that the curved portion 33a is further curved concavely toward the axis O side. Therefore, the force is suppressed from causing creases in the pair of bent portions 33.

In this way, in the synthetic resin flat container 1 of this embodiment, the pair of bent portions 33 that are provided on both the left and right sides of the flat-shaped body 30 and form the boundary between the front wall 31 and the rear wall 32 are configured to have a curved portion 33a that is curved concavely toward the axis O. Therefore, even if the internal pressure of the container 1 increases and the front wall 31 and the rear wall 32 deform so as to expand in the front-to-rear direction and a force is applied to the pair of bent portions 33 that tends to constrict them toward the inside of the container, the curved portion 33a smoothly deforms in response to the force so as to be curved further concavely toward the axis O, thereby preventing the pair of bent portions 33 from being wrinkled.

The curved depth D of the curved portion 33a of the pair of bends 33 is preferably 0.10 mm or more and 5.00 mm or less, and more preferably 0.50 mm or more and 5.00 mm or less. In this embodiment, the curved depth D of the curved portion 33a of the pair of bends 33 is 0.75 mm.

As shown in FIG. 1, the curve depth D of the curved portion 33a is the distance from an imaginary straight line L connecting the upper end and lower end of the bend 33, where the curved portion 33a is not provided, to the portion of the curved portion 33a that is located closest to the axis O.

By setting the curve depth D of the curved portion 33a of the pair of bends 33 to 0.10 mm or more, it is possible to more effectively prevent the pair of bends 33 from forming creases when the synthetic resin flat container 1 is made of a relatively soft material such as polyethylene (PE).

In addition, by setting the curve depth D of the curved portion 33a of the pair of bends 33 to 0.50 mm or more, it is possible to more effectively prevent the pair of bends 33 from developing creases. This makes it possible to more effectively prevent the pair of bends 33 from developing creases, regardless of the material used to form the synthetic resin flat container 1.

The upper limit of the curve depth D of the curved portion 33a of the pair of bent portions 33 is preferably 5.00 mm or less. By setting the curve depth D to 5.00 mm or less, the pair of bent portions 33 can be easily molded and the body portion 30 can be made to have good squeezability. Furthermore, it is more preferable that the upper limit of the curve depth D of the curved portion 33a of the pair of bent portions 33 is 2.50 mm or less. This allows the pair of bent portions 33 to be molded even more easily and the body portion 30 can be made to have good squeezability.

As shown in FIG. 1, in the pair of bent portions 33, it is preferable that the upper end 33a1 of the curved portion 33a is within 1/4 of the range extending downward from the upper end of the body 30, and the lower end 33a2 is within 1/4 of the range extending upward from the lower end of the body 30. This configuration can effectively prevent creases from occurring in the pair of bent portions 33 over a wider range of the body 30 in the vertical direction.

In this embodiment, in the pair of bent portions 33, the upper end 33a1 of the curved portion 33a coincides with the upper end of the body 30, and the lower end 33a2 is provided within 1/4 of the range upward from the lower end of the body 30. In this way, by configuring the upper end 33a1 of the curved portion 33a to coincide with the upper end of the body 30, it is possible to effectively prevent the pair of bent portions 33 from being wrinkled on the side of the shoulder portion 20, which is prone to expansion during hot filling due to the provision of a head space.

As shown in Figures 3 to 5, in this embodiment, the cross sections of the front wall 31 and the rear wall 32 in the portions where the curved portions 33a are not provided are each arc-shaped with their center points shifted in the front-rear direction from the axis O. As shown in Figure 5, the cross sections of the front wall 31 and the rear wall 32 in the portions where the curved portions 33a are provided are similarly arc-shaped in the left-right center portion, and are linear near the pair of bends 33 and connected to the bends 33. In this way, by making the cross sections of the front wall 31 and the rear wall 32 in the portions where the curved portions 33a are not provided arc-shaped, it is possible to make it easier to squeeze the body 30 in the front-rear direction.

In addition, in this embodiment, as described above, the body 30 is symmetrical in the front-to-back and left-to-right directions, making it easier to squeeze the body 30 in the front-to-back direction, while the curved portions 33a provided in the pair of bends 33 effectively prevent creases from occurring in each bend 33.

Furthermore, in this embodiment, the synthetic resin flat container 1 is formed by extrusion blow molding, so the synthetic resin flat container 1 having the above configuration can be manufactured easily and inexpensively.

The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the invention.

For example, in the above embodiment, the curved portion 33a is provided in a portion of the pair of bent portions 33, but this is not limited thereto, and the entire pair of bent portions 33 may be curved portions 33a.

In addition, in the above embodiment, the curved depth D of the curved portion 33a is 0.75 mm, but this is not limited to this and the depth can be changed in various ways, for example to 1.50 mm.

In addition, in the above embodiment, the body 30 has a shape in which the front wall 31 and the back wall 32 are curved in an arc, but the front wall 31 and the back wall 32 may also be configured to have uneven portions, etc.

In addition, in the above embodiment, the container 1 has a single-layer structure, but it may have a laminated structure, and may be decorated with printing, labels, etc.

Reference Signs List 1: synthetic resin flat container 10: mouth 11: male thread 12: tip opening 13: neck ring 20: shoulder 30: body 31: front wall 32: rear wall 33: bent portion 33a: curved portion 33a1: upper end 33a2: lower end 40: bottom O: axis S: storage space T: thickness W: width D: curved depth L: imaginary straight line

Claims (8)

A flat container made of synthetic resin, comprising a cylindrical mouth, a shoulder connected to the mouth, a body connected at an upper end to the shoulder, and a bottom connected to a lower end of the body, the body having a flat shape with a width in the left-right direction greater than a thickness in the front-rear direction and configured to be squeezable,
The body portion is
A front wall curved so that a central portion in the left-right direction protrudes forward relative to an axis line;
a rear wall that is curved such that a central portion in a left-right direction protrudes rearward with respect to the axis and faces the front wall across the axis;
a pair of bent portions each constituting a boundary between the front wall and the rear wall at both ends in the left-right direction,
The pair of bending portions each include a curved portion that is curved concavely toward the axis line in a front view , at least in a part of the pair of bending portions,
A flat container made of synthetic resin, characterized in that the bottom has a semicircular shape convex downward when viewed from the front. The synthetic resin flat container according to claim 1, wherein the depth of the curved portion is 0.10 mm or more and 5.00 mm or less. The synthetic resin flat container according to claim 1, wherein the depth of the curved portion is 0.50 mm or more and 5.00 mm or less. The upper end of the curved portion is within a range of 1/4 from the upper end of the body,
The synthetic resin flat container according to any one of claims 1 to 3, wherein the lower end of the curved portion is within 1/4 of the range from the lower end of the body portion. The flat container made of synthetic resin according to claim 4, wherein the upper end of the curved portion coincides with the upper end of the body. The synthetic resin flat container according to any one of claims 1 to 5, wherein the cross sections of the front wall and the rear wall at the portions where the curved portions are not provided are each arc-shaped. The synthetic resin flat container according to any one of claims 1 to 6, wherein the body has a shape that is symmetrical front-to-back and left-to-right. A flat synthetic resin container according to any one of claims 1 to 7, formed by extrusion blow molding.

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