Receptacles – Closures – With closure opening arrangements for means
Patent
1990-02-28
1992-07-21
Marcus, Stephen
Receptacles
Closures
With closure opening arrangements for means
220276, 220359, B65D 1734
Patent
active
051315564
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention relates to an improvement in an easy-open lid comprising a laminate of a metal foil and a resin and an opening weakened line formed in the laminate, in which occurrence of ribbon breaking at the time of opening is prevented.
2. Technical Background
An easy-open lid comprising a laminate of a metal foil and a resin is widely used as a sealing lid for a light-weight vessel comprising a metal foil, a resin, a paper or a laminate thereof as the constituent material. In this easy-open lid, an opening weakened line defining a portion to be opened is formed in the laminate and an opening tab is fixed to the opening-initiating point of the portion to be opened, and opening is effected by breaking the lid along the weakened line.
In the field of the easy-open lid of this type, a so-called full-open lid in which an opening is formed on the substantially entire surface of the lid is desired. For this full-open lid, there is generally adopted a structure in which, as shown in FIG. 5-I of Japanese Patent Application Laid-Open Specification No. 152145/84, a portion to be opened is defined by an outer peripheral weakened line, an outside introducing weakened line and an inside introducing weakened line are formed, tearing is effected in a ribbon-like shape from an opening-initiating point, and then, the entire surface is opened.
In this full-open easy-open lid, ribbon breaking is often caused at the time of opening, rendering opening of the entire surface difficult. The term ribbon breaking means the phenomenon in which the ribbon-shaped portion defined by the outside introducing weakened line and the inside introducing weakened line undergoes a concentrated opening force at the initial stage of opening and is broken at the point close to the part most protruding in the opening-initiating direction of the inside introducing weakened line. This ribbon breaking is a phenomenon not observed in an easy-open can lid formed of an aluminum sheet, and this is a trouble occuring inherently in a lid formed of a laminate of a metal foil and a resin.
3. Gist of the Invention
It is therefore a primary object of the present invention to provide an easy-open lid of he above-mentioned metal foil/resin type, in which occurrence of ribbon breaking is prevented and opening of the entire surface of the lid can be performed assuredly and smoothly without failure.
More specifically, in accordance with the present invention, there is provided an easy-open vessel lid comprising a lid member composed of a laminate of a metal foil and a resin, a peripheral weakened line formed in the lid member, a portion to be opened, which is defined by the peripheral weakened line, an outside introducing weakened line, which is formed in the portion to be opened and reaches the peripheral weakened line, an inside introducing weakened line, which is formed in the portion to be opened and does not reach the outer peripheral weakened line, an opening-initiating part and a ribbon-shaped portion, which are defined by the outside introducing weakened line and the inside introducing weakened line, and an opening tab connected to the opening-initiating part, wherein a reinforcing layer of a thermoplastic resin is formed independently from said resin at least on the outer periphery side of a part most protruding in the opening-initiating direction of the inside introducing weakened line to cover said weakened line astride of said weakened line.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows curves of the distribution of the tear strength of (A) a laminate having a weakened line and (B) a product obtained by forming a reinforcing resin layer astride of this weakened line of this laminate.
FIG. 2 is a top view showing an embodiment of the easy-open lid of the present invention.
FIG. 3 is a view showing the section taken along the line III--III of the lid shown in FIG. 2.
FIG. 4 is a view showing the section taken along the line IV--IV of the lid shown in FIG. 2.
FIG. 5 is a top view showing a lid in which a reinfor
REFERENCES:
patent: 4556152 (1985-12-01), Bogren
patent: 4572393 (1986-02-01), Kobayashi et al.
patent: 4784284 (1988-11-01), Miyauchi et al.
Hatano Yasushi
Iioka Toshiaki
Kaga Yasuo
Kurashima Hideo
Taira Kazuo
Marcus Stephen
Sucker Nova
Toyo Seikan Kaisha Ltd.
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