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Container with twist-off tamper evident feature
| Details |
Inventors: Holoubek, George H.; Anthony, Eugene M.; Hans, Allan B.;
Assignee: Wheeling Stamping Company (Wheeling, WV)
Primary Examiner: Werner; Frank E.
Assistant Examiner: Smith; P. McCoy
Attorney, Agent or Firm: Parmelee, Miller, Welsh & Kratz
An integral seal member is formed across the outlet in the neck of a tamper evident, thermoplastic container by adding to the thermoplastic material such as polyethylene, 3% to 16%, and preferably about 8% by weight, of an anhydrous solid inorganic particulate additive such as an anhydrous siliceous material or calcium carbonate so that the material becomes brittle enough that the seal member tears cleanly from the neck within the confines of an undercut at the interface between the seal member and neck. Torque is applied to the seal member by providing in the top of a conventional screw cap which forms a resealing closure for the container once opened, a recess with serrations which, when the cap is removed and turned upside down, engage serrations on the peripheral edge of the seal. |
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DETAILED DESCRIPTION These and other objects are realized by a container in which the neck and an integral sealing member extending across an outlet in the neck define a thinner, weaker separation line between them along which the sealing member can be torn from the neck to open the outlet, and in which the neck and sealing member are made of a thermoplastic material containing an anhydrous solid inorganic particulate material having an average particle size of 10 microns or less in a sufficient amount to make the thermoplastic material brittle enough that the tear between the sealing member and neck is confined to the separation line.
Such an arrangement provides a tamper evident container in which the sealing member tears cleanly away from the neck to leave a smooth edge on the outlet.
Preferably, the thermoplastic material is polyethylene and the anhydrous solid inorganic particulate material is selected from a group comprising an anhydrous siliceous material and calcium carbonate.
The polyethylene contains three to sixteen, and preferably eight, percent by weight of the selected solid particulate material.
These preferred solid particulate materials in the stated proportions make the polyethylene brittle enough that it separates cleanly along the separation line which is important to the commercial acceptability of the tamper-evident containers for consumer products.
Many of the preferred solid particulate materials do not discolor the polyethylene which is important in some applications.
In the preferred form, the neck of the container is cylindrical and the sealing member is axially aligned with the end of the neck so that the separation line is defined by an annular groove.
The neck tapers axially inward toward, and the bottom of the circular seal member extends radially outward from, this annular groove, and a blind bore extends axially into the center of the seal member from the inside beyond the annular groove, such that the stresses applied to the seal member are concentrated at the separation line
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Adhesives and Rubbers 
