JPH04128141A - Plastic container lid - Google Patents

Abstract

PURPOSE:To prevent firmly excessive dropping down of pressing force of a sealing member for the mouth part when applied with a load on the upper surface of a lid, so that defective sealing can be surely avoided by forming a part of a skirt wall of non-foamed plastic having a specified elasticity. CONSTITUTION:A body 4 having a ceiling wall 8 and a skirt wall 10 is formed of ordinary non-foamed plastic having an elasticity of more than 5000kg/cm<2> and the skirt wall 10 includes a high elasticity part 18 of an elasticity of 1000 to 3000kg/cm<2>. When a load is applied on the up[per surface of a container lid, the high elasticity part 18 is force to decline the skirt wall 10 positively inward in a radial direction and downward by a recovering force, while the container lid itself is kept moved slightly downward, so that an upper side surface of a female screw thread 14 of the skirt wall 10 is brought into contact with a lower side surface of a male screw thread of a mouth part 22. Accordingly, when the movable load is removed, the body 4 is prevented from rising up and a dropdwon of the pressing force of a sealing member 6 for the top surface of the mouth part 22 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a plastic container lid, and more particularly to a plastic container lid in which a foamed plastic sealing member is disposed on the inner surface of the top wall.

[Prior art]

As a container lid particularly suitable for glass containers (bottles) containing alcoholic beverages such as sake and whiskey, the main body has a top wall and a cylindrical skirt wall that hangs down from the periphery of the top wall, and the top of the main body. Container lids are widely used that include a sealing member disposed on the inner surface of a face wall. The body is made of conventional non-foamed plastic, while the sealing member, which is pressed against the top surface of the neck of the container, is made of foamed plastic. A female thread is formed on the inner surface of the skirt wall of the main body, and is screwed into a male thread formed on the outer surface of the mouth and neck of the container.

[Problems with conventional technology]

When various experiments and analyzes were conducted on the conventional container lid as described above, it was found that the conventional container lid had the following problems.

At a content filling factory, after filling a container with contents such as alcoholic beverages, a container lid is fitted to the mouth and neck of the container.
Use torque to tighten to about a cm, and attach the lid to the mouth and neck (
(Screw the female thread on the skirt wall into the male thread on the mouth and neck). In this way, the sealing member of the container lid is pressed against the top surface of the mouth and neck, and the mouth and neck are sealed. The container, filled with contents and fitted with a container lid, is placed in a case for transportation, and
Then, they are stacked vertically with pallets interposed. In this case, a so-called live load of about 50 to 80 kg per container is often applied to the top surface of the container lid of the lowermost container. When the initial tightening of the container lid is applied with torque and the above-mentioned load is applied, a considerably large stress is generated in the foamed plastic sealing member, and the sealing member is excessively compressed and deformed. When the above-mentioned vertical stacking is released, the pressing force of the sealing member against the top surface of the mouth and neck area decreases excessively, and the sealing of the mouth and neck area is damaged due to this. It will be done. When the pressing force of the sealing member against the top surface of the mouth and neck area decreases excessively, for example, when the container is placed on its side,
Leakage of contents may also occur. (Such problems with conventional container lids will be further referred to later.) [Problems to be solved by the Invention] The present invention has been made in view of the above facts, and its main technical problem is to prevent the above-mentioned loading on the top surface of the container lid. To reliably prevent the pressing force of a sealing member against the mouth and neck from decreasing excessively even when a load is applied, and thus surely avoid damage to the seal on the mouth and neck due to the live load. That's true.

[Means for solving the invention]

The solution of the present invention for achieving the above technical problem is to provide a part of the skirt wall with an elastic modulus of 1000 to 3000.
kg/cm! It is made from non-foamed plastic. In addition, the term "elastic modulus" used in this specification
means the elastic modulus measured by the bending test method specified in JIS:7203.

That is, according to the present invention, a main body made of non-foamed plastic has a top wall and a cylindrical skirt wall hanging from the periphery of the top wall, and a seal member made of foamed synthetic resin disposed on the inner surface of the top wall. A plastic container lid comprising: an internal thread formed on the inner peripheral surface of the skirt wall;
The skirt wall has an elastic modulus of 1000 to 3000 kg/
The remainder of the skirt wall and the top wall have a modulus of elasticity of 500.
A container lid is provided, characterized in that it is made of ordinary plastic with a weight of 0 kg/C11 or more.

The high elasticity part of the skirt wall extends continuously on the outer circumferential surface part of the skirt wall or in the middle part in the thickness direction, or extends in the circumferential direction.
j%. Suitable examples of plastics having a high elastic modulus include ethylene-boropylene copolymer, mixture of ethylene-propylene copolymer and polyolefin, mixture of styrene-ethylene-butadiene-styrene copolymer and polyolefin, ethylene Examples include high-modulus polypropylene with a high content of , high-modulus polyester, a mixture of high-modulus polyester and polyolefin, and vinyl chloride.

[Action of the invention]

When the container lid is attached to the neck of the container by applying the required initial tightening torque, the skirt wall will be radially tightened due to the interaction between the female thread on the neck and the male thread on the skirt wall, as in the case of conventional container lids. It is forced downwardly and somewhat radially outwardly in response to an outwardly directed force. and,
When the initial tightening is torqued and the load is applied, the container lid is caused to move somewhat downward. Thus, in the case of the conventional container lid, the female thread on the skirt wall is separated downward from the male thread on the neck, but in the case of the container lid of the present invention, the elastic restoring action of the highly elastic portion of the skirt wall allows the skirt to The walls are displaced radially inward so that the internal threads of the skirt wall remain engaged with the external threads of the neck despite the downward movement of the container lid. Even when the above-mentioned live load is released, the instantaneous upward movement of the container lid is prevented due to the engagement between the female thread on the skirt wall and the male thread on the neck, thus preventing the over-compressed foam. Even if the plastic sealing member is not restored quickly, the pressing force of the sealing member against the top surface of the mouth and neck continues to be maintained above the required value.

(In the case of conventional container lids, when the live load is released,
Due to the gap between the female thread on the skirt wall and the male thread on the neck and neck, the container lid was instantly moved upwards, while the over-compressed foam plastic took a long time to recover. However, there is a risk that the pressing force of the sealing member against the top surface of the mouth and neck area may be excessively reduced. In order to achieve the above problem, it may be possible to form the entire skirt wall (and top wall) from high elastic plastic, but
In this case, the rigidity of the container lid is excessively reduced, and the coefficient of friction of the female threaded surface of the skirt wall is also excessively increased, making it extremely difficult to open and close the container lid.

If the modulus of elasticity of the plastic that constitutes the high elasticity portion of the skirt wall is excessively high, the desired restoring effect cannot be obtained, and conversely, if the modulus of elasticity is excessively low, the rigidity of the entire skirt wall becomes excessively low.

[Preferred specific examples of the invention]

Hereinafter, preferred embodiments of the container lid of the present invention will be described in more detail with reference to the accompanying drawings.

Referring to FIG. 1, the illustrated container lid 2 constructed according to the present invention is comprised of a main body 4 and a sealing member 6. As shown in FIG. The main body 4 has a circular top wall 8 and a cylindrical skirt wall 10 depending from the periphery of the top wall 8. The outer surface of the skirt wall 10 is provided with unevenness or low left 1 to prevent slipping.
2 is formed. A female thread 14 is formed on the inner surface of the skirt wall 10. Furthermore, an annular locking protrusion 16 is formed on the upper inner surface of the skirt wall 10. The sealing member 6 having a disc shape is molded separately from the main body 4 and is disposed on the inner surface of the top wall 8. The peripheral edge of the sealing member 6 is elastically deformed to pass through the annular locking protrusion 16,
This annular locking protrusion 16 maintains it in the required position.

The main body 4 having the top wall 8 and the skirt wall 10 has an elastic modulus of 5000 kg/c1, except for a part of the skirt wall 10, as will be mentioned later. It is made of a conventional non-foamed plastic such as polypropylene or polyethylene. On the other hand, the seal member 6 is made of a suitable foamed plastic such as foamed polyethylene. If desired, an annular sealing member can be used instead of the disc-shaped sealing member 6. In addition, the seal member 6
Instead of molding separately from the main body 4, an unfoamed plastic material may be applied to the inner surface of the top wall 8 of the main body 4, and the plastic material may be foamed on the inner surface of the top wall 8.

Therefore, when wiping the container lid 2 constructed according to the present invention, the skirt wall 10 has an elastic modulus of 1000 to 3000 kg.
/cd high elasticity part 18 made of plastic
It is important to include

In the specific example illustrated in FIG. 1, the high elasticity portion 18 in the skirt wall 10
It extends continuously in the circumferential direction except for its upper end. Since high elasticity plastics usually have a high coefficient of friction, the female thread 14 cooperates with the male thread formed on the neck and neck of the container.
Advantageously, there are no highly elastic parts present. Preferred examples of the plastic forming the high elasticity portion 18 include ethylene-propylene copolymer, a mixture of ethylene-propylene copolymer and polyolefin, and styrene-ethylene-propylene copolymer.
Mixture of butadiene-styrene copolymer and polyolefin, high modulus polypropylene with high ethylene content,
Mention may be made of high modulus polyesters, mixtures of high modulus polyethylene and polyolefins, and vinyl chloride. In the main body 4 in which a part of the skirt wall 10 is made of a different material from the other parts, the high elasticity part 18 is separately molded and attached to a desired part of the main body 40 (by heat fusion, adhesive bonding, etc.). It can be formed by joining or by an injection molding method known as a two-color injection molding method.

Referring to FIG. 2 in conjunction with FIG. 1, a container closure 2 constructed in accordance with the present invention is applied to a container 20 which may be formed from glass or any suitable non-foamed plastic such as polyethylene terephthalate. The container 20 has a neck 22 having a generally cylindrical shape, and an external thread 24 is formed on the outer surface of the neck 22 . The container is filled with required contents such as alcoholic beverages, and then the container lid 2 is attached. The attachment of the container lid 2 is carried out at the mouth and neck area 2.
2, and the required tightening torque is approximately 22 kg-c if the outer diameter of the container lid 2 is 30 cm.
Rotate the container lid 2 clockwise when viewed from above in FIG. Screw it into thread 24. In this way, since the container lid 2 is moved downward, the sealing member 6 is pressed against the top surface of the neck part 22, as clearly shown in FIG. It is compressed between the top surface and the mouth and neck part 22 is sufficiently sealed. A radially outward force is also applied to the female thread 14 from the male thread 24, and this force causes the skirt wall 10 to
is from the state shown by the two-dot chain line in Fig. 2 to the 21st! It is displaced to the state shown by the solid line I, that is, it is displaced to a state in which it is somewhat inclined downward in the radial direction. When the tightening torque is released, an upward force is applied from the compressed sealing member 6 to the top wall 8 of the main body 4, causing the main body 4 to rise somewhat 1. Therefore, the internal thread 14 of the skirt wall 10
The lower surface of the skirt wall 10 is separated from the upper surface of the neck part 22, and the upper surface side of the female thread 14 of the skirt wall 10 is brought into contact with the lower surface of the male thread 24 of the neck part 22.

After the container lid 2 is attached to the mouth and neck part 22 as described above, the container 2 with the container lid 2 attached is normally housed in a case, and then vertically moved with a pallet interposed therebetween. Can be stacked in several tiers. Then, it is loaded onto a truck or the like for transportation. In this case, a load of approximately 50 to 80 kg per container is applied to the upper surface of the container lid 2 of the lowermost container 20. When such a live load is applied, the sealing member 6 is further compressed, and the main body 4 is further moved downward to some extent, as shown in FIG. 3, the upper surface of the female thread 14 of the skirt wall 10 is spaced downwardly from the lower surface of the male thread 24 of the neck portion 22. In conventional container lids, the skirt wall is maintained in the state shown by the two-dot chain line in FIG. 1
There is some gap between the upper side of 4 and the lower side of the male thread 24 of the neck part 22. However, in the container lid 2 constructed according to the present invention, the skirt wall 10
Due to the restoring action of the high elasticity portion 18 disposed in the third
As shown by the solid line in the figure, although the container lid 2 itself remains moved somewhat downward, the internal threads 1 of the skirt wall 10
The upper surface of 4 is brought into contact with the lower surface of the external thread 24 of the oral portion 22.

When the stacked state is released and the load applied to the top surface of the container lid 2 is released, the main body 4 rises due to the upward force applied from the compressed seal member 6 to the top wall 8 of the main body 4. I'm going to be forced to do it. However, in the container lid 2 constructed according to the present invention, since the upper surface of the female thread 14 of the force-F wall 10 is brought into contact with the lower surface of the male thread 24 of the neck portion 22 as described above, The main body 4 is prevented from rising, and the pressing force of the seal member 6 against the top surface of the mouth and neck portion 22 is prevented from decreasing. In contrast, in conventional container lids, when the load is released, the main body 4 is raised somewhat, while the foamed plastic sealing member 6, which had been compressed until then, has a small restoring force and instantly rises. Therefore, the pressing force of the sealing member against the top surface of the mouth and neck is temporarily and significantly reduced.

4 and 5 and 6 illustrate variations of container closures constructed in accordance with the present invention.

In the modification shown in FIG. 4, the high elasticity portion 18 in the skirt wall 10 of the main body 4 extends continuously in the circumferential direction not on the outer circumferential surface of the skirt wall 10 but on the intermediate portion in the thickness direction thereof. There is. In the modification illustrated in FIGS. 5 and 6, the high elasticity portions 18 do not extend continuously in the circumferential direction but are present at a plurality of locations spaced apart in the circumferential direction. The high elasticity portion 18 is formed in the skirt wall 1 in the thickness direction.
0 from the inner surface to the outer surface of the main body portion, but does not exist in the female thread 14. In the illustrated modification, the internal thread 14 formed on the inner surface of the skirt wall 10 is
The portion where the high elasticity portion 18 is present is placed in the middle. As shown in FIG. 6, the cross-sectional shape of the high elasticity portion 18 is not a simple rectangle, but is made relatively complex with unevenness so as to sufficiently prevent separation from other portions. ing.

〔Effect of the invention〕

According to the container lid of the present invention, even when a considerably large load is applied to the top surface of the container lid, the pressing force of the sealing member against the top surface of the mouth and neck of the container is reliably prevented from decreasing excessively. The mouth and neck seal is maintained without damage.

[Brief explanation of drawings]

FIG. 1 is a side view, partially in section, of a preferred embodiment of a container lid constructed in accordance with the present invention. FIG. 2 is a partial sectional view for explaining the behavior of the container lid shown in FIG. 1 when the container lid shown in FIG. 1 is attached to the mouth and neck of the container. FIG. 3 is a partial sectional view for explaining the behavior of the container lid when a live load is applied to the upper surface of the container lid and then the live load is removed. FIG. 4 is a side view, partially in section, of a modified example of the container lid constructed according to the present invention. FIG. 5 is a side view, partially in cross section, of still another modified example constructed according to the present invention. FIG. 6 is a partial sectional view taken along the line ■-■ in FIG. 2...Container lid 4...Container lid body 6...Sealing member 8...Top wall lO...Skirt wall 14...Female thread 18 ... High elasticity part 20 ... Container 22 ... Container neck and neck part 24 ... External thread Figure 2 $30 $6 round di

Claims (1)

[Claims] 1. A non-foamed plastic main body having a top wall and a cylindrical skirt wall hanging from the periphery of the top wall, and a foamed synthetic resin sealing member disposed on the inner surface of the top wall. In the plastic container lid, the skirt wall has a female screw thread formed on the inner circumferential surface thereof, and the skirt wall has a high elasticity portion made of plastic having an elastic modulus of 1000 to 3000 kg/cm^3. 2. A container lid, wherein the remainder of the skirt wall and the top wall are made of ordinary plastic having an elastic modulus of 5000 kg/cm^3 or more. 2. The container lid according to claim 1, wherein the high elasticity portion extends continuously in the circumferential direction on the outer peripheral surface of the skirt wall. 3. The container lid according to claim 1, wherein the high elasticity portion extends continuously in the circumferential direction in the thickness direction intermediate portion of the skirt wall. 4. The container lid according to claim 1, wherein the high elasticity portions are present in a plurality of regions spaced apart in the circumferential direction. 5. The high elasticity portion is made of an ethylene-propylene copolymer, a mixture of an ethylene-propylene copolymer and a polyolefin, a mixture of a styrene-ethylene-butadiene-styrene copolymer and a polyolefin, or a mixture of ethylene-propylene copolymer and polyolefin. 6. The container lid according to claim 1, wherein the container lid is formed from any one of high modulus polypropylene, high modulus polyester, a mixture of high modulus polyester and polyolefin, and vinyl chloride.