JPS6344627B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plastic sealing lid for containers, especially bottles.

Metal crowns have been used as sealing lids for containers for many years and are lined with various materials such as cork, rubber, thermoset plastics and thermoplastics, and the like. Representatives of numerous crowns lined with such materials are U.S. Pat.
No. 2684774, 2688776, 2696318, 2823422
No. 2834498, 2840858, 2952035, 3183144
No. 3278985 and No. 3300072.

Recently, the benefits of plastic crowns or sealing lids have been recognized. However, physical properties of plastics such as melt plastic deformation temperature,
Due to the elasticity, impact compressive strength, and freezing temperature during molding, problems arise in the molding of plastic closures that are different from those encountered in forming metal closures.

For example, in the case of prior art plastic closures, the wall thickness is limited to a limited range. That is, the walls must be thin enough to allow the threaded circumference of the sealing lid to be removed and deflected axially from the plunger, yet thick enough to support the required thread height and shape. Must be. The threads of an ordinary plastic sealing lid are
It must have a certain degree of taper so that the threaded wall can be removed and deflected from the plunger.

With common plastic closures, such as polypropylene closures, the closures have low impact strength and fail drop tests at temperatures ranging from 0° to 4° Celsius (32° to 40° Fahrenheit). Become. On the other hand, conventional plastic sealing lids require an extremely long and expensive time to manufacture. Moreover, as a lid for sealing containers containing high-pressure drinking water, etc.,
Plastic versions did not provide a sufficiently effective seal.

The present invention overcomes the above-mentioned problems of the prior art and aims to provide a plastic sealing lid which is extremely easy to manufacture and which can effectively seal the container. .

According to the present invention, there is provided a plastic sealing lid for a container, which includes a top wall, an annular peripheral wall having a thread on the inner surface and hanging from the top wall, and a top wall and the thread. a plastic cap having an annular backing retention lip extending inwardly from the annular peripheral wall between the ridges and located within the plastic cap adjacent to the top wall; a plastic sealing backing having an annular seal retained in engagement by the annular backing retaining lip; a generally inwardly facing sealing surface for sealing engagement, the sealing backing being compression molded within the plastic cap and connecting a central portion and the annular sealing portion; A plastic sealing lid is provided, wherein the annular backing retaining lip has a surface that molds the sealing backing during compression molding.

Compression molding the plastic sealing liner in accordance with the arrangement described above greatly facilitates the manufacture of the sealing lid, and the plastic sealing liner thus compression molded provides a sealing connection to the container. Having generally inwardly facing sealing surfaces for mating and a central portion are adapted to effectively seal the mouth of the container on its outer and top surfaces.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a plastic sealing lid 100
is a container 1 filled with a liquid such as a carbonated drink.
The mouth of 02 is closed to seal the liquid. Sealing lid 1
00 has a resilient plastic cap 104, often referred to as a crown, and a resilient, fluid-impermeable plastic sealing backing 1.
There is 06. Plastic cap 104 is preferably made from a moldable thermoplastic material such as polypropylene, polyethylene, etc., although other materials may be used. The sealing backing 106 is preferably made from a moldable thermoplastic material such as polyvinyl chloride (PVC), but may also include other backing materials such as ethylene vinyl acetate (EVA).
can also be used.

To increase the strength of the plastic cap 104, the cap 104 has a plastic portion that is turned to form a helical molecular arrangement. The helical arrangement provides the cap with greater hoop strength and crack resistance than caps formed without the helical arrangement.
The turn-molded plastic material provides good impact strength, allowing the cap to pass drop tests at cooling temperatures ranging from 0° to 4° Celsius (32° to 40° Fahrenheit).

Preferably, cap 104 has a unitary structure and is made from polypropylene homopolymer. All parts of plastic cap 104 are integrally connected to each other. The cap 104 has a top wall 110 and an annular peripheral wall 112 that hangs down from the top wall 110. Top wall portion 110 has a generally flat outer surface 110a and an inner surface 110b. A circular edge 110c formed where the top wall 110 and the peripheral wall 112 intersect is rounded.

As shown in FIG. 2, the peripheral wall 112 has internal threads 114 and an inwardly extending annular backing retention lip 116 that provides an annular seal 106a of the backing 106. A surface is formed which retains the backing 106 during the backing molding process. As will be described later, the annular sealing portion 106a suitably seals all irregularly shaped portions such as bulges and irregularities at the mouth of the container. The lips 116 are angled and converge radially inwardly from the top wall 110.

The outer surface of the peripheral wall 112 includes circumferentially spaced vertical ribs 120 to facilitate finger gripping of the cap 104. The rib 120 extends to a lower end 124 remote from the top wall 110. The lower end 124 has an inwardly slanted annular shoulder 126 forming a peripheral wall of this end.

In order to indicate whether the plastic sealing lid 100 has been opened after it has been inserted and screwed into the container 102, the lower end of the peripheral wall 112 in the illustrated embodiment includes a heat-shrinkable removable Theft display band 128 is a plurality of fragile parts 1
30. This thief indication band 128 is in the peripheral wall portion 1 in the as-molded state.
It has a truncated conical shape extending convergently inward in the radial direction from 12 , and the inner diameter of the tip thereof is smaller than the inner diameter within the peripheral wall portion 112 . This stealth indication band 128,
After that, the peripheral wall part 1 is expanded by pushing outward in the radial direction.
The cap 104 can be inserted onto the container 102 after being shaped into a cylinder having an inner diameter approximately equal to the inner diameter of the container 12 . The cylindrical band 128 has heat recovery properties and returns to its original truncated conical shape when reheated.

After the sealing lid 100 is inserted and screwed onto the container 102, the tamper-evident band 128 is heated, causing the band 128 to contract around and engage the neck of the container. When the sealing lid 100 is screwed back and the mouth of the container 102 is opened, the thief indicator band 128 is removed from the fragile portion 13.
Breaks at 0. In the preferred embodiment, some of the plurality of frangible portions 130 are thicker than others so that when the sealing lid 100 is removed from the container, the tamper-indicating band 128 is in one or more pieces. It is still connected to the sealing lid 100 by a thickened section that can be torn off. In some cases, the frangible portions 130 may all have the same thickness and be scored only horizontally so that the tamper-evident band 128 remains on the container 102 when the sealing lid 100 is removed.

Cap 104 has a plurality of protrusions 132 that interengage with sealing backing 106 to provide a secure mechanical relative connection between sealing backing 106 and cap 104. The protrusion 132 extends vertically from the inner surface 110b of the top wall 110 to the cap 104.
1 to a position above the annular backing retaining lip 116 (FIG. 1).

A plastic sealing backing 106 is connected to an annular sealing portion 106a and includes a sealing portion 106a.
Disk-shaped central portion 106b surrounded by a (Fig. 1)
is provided. The central portion 106b is the top wall portion 11
1, and lies below the head of the protrusion 132 (in FIG. 1), completely covering the protrusion 132. The annular seal 106a is constrained in the space between the inner surface 110b of the top wall 110 and the lip 116. The outer surface of the sealing portion 106a has a rounded lower edge portion 142 (FIG. 2) that is shaped to fit into a rounded corner connecting the top wall portion 110 to the peripheral wall portion 112. ing. Further, the sealing portion 106a is inclined so that the top wall portion 1
It has a frusto-conical portion 144 that converges radially inwardly from 10 to engage lip 116 . The inner surface of the sealing portion 106a includes a vertical sealing surface 14.
6 and a frusto-conical sealing surface 148 that slopes and extends radially outward from this sealing surface 146. The sealing surface 148 resiliently seals the outer surface of the container mouth and completely seals fluid-tightly over irregularities such as bulges, irregularities, etc. in the mouth. If a thermoplastic sealing backing 106, such as an EVA backing, is used, the sealing backing 106 is heated during the compression molding backing process and is thermally bonded to the protrusion 132 (FIG. 2). Ru.

As explained above, according to the invention of the present application, a plastic sealing lid can be manufactured extremely easily, and the opening of the container can be effectively sealed from the top and sides. can.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a plastic sealing lid according to an embodiment of the present invention screwed into the mouth of a container, and FIG. 2 is an enlarged sectional view of the plastic sealing lid shown in FIG. 1. It is. 100...Plastic sealing lid, 104...
Plastic cap, 106... plastic sealing backing, 106a... annular sealing part,
106b...Central part, 110...Top wall part, 110
b... Inner surface, 112... Peripheral wall portion, 114... Screw thread, 116... Backing retaining lip portion, 128... Stealth indication band, 130... Brittle portion.

Claims (1)

[Claims] 1 Plastic sealing lid for containers 100
and a top wall portion 110, an annular peripheral wall portion 11 having threads 114 on the inner surface and hanging from the top wall portion.
2, and a plastic cap 104 having an annular backing retention lip 116 extending inwardly from the annular peripheral wall 112 between the top wall 110 and the threads 114; a plastic sealing backing 106 located within the plastic cap 104 adjacent portion 110, the sealing backing 106 being engaged by the annular backing retaining lip 116. a retained annular seal 106a having generally inwardly facing sealing surfaces 146, 148 for sealingly engaging a container, said sealing backing 106 plastic cap 10
4 by compression molding,
The annular backing retaining lip 116 includes a central portion 106b and an annular sealing portion 106a, the annular backing retaining lip 116 providing a surface for forming the sealing backing 106 during compression molding. Plastic sealed lid.