The present disclosure relates to container closures using natural looking synthetic cork, as well as a method of making synthetic cork stoppers.

Producers of liquid consumable products, such as wine, liquor and other products, that are sold in bottles or other containers that are traditionally closed and sealed with cork stoppers have long been concerned about contamination due to the cork, which can lead to spoilage or alteration of the product within the container. In the case of wine or cooking oil, for example, such spoilage is immediately noticeable by the consumer and renders the product unfit for consumption.

For that reason, there has been a movement in recent times toward the use of synthetic stoppers in place of cork. If the synthetic materials used are non-reactive with the contents of the container, the synthetic stopper is a viable solution to the problem of contamination due to the cork, and consequently the contents of the container.

One configuration of such synthetic cork stopper comprises a synthetic cork bonded to a cap. With reference to PRIOR ART FIGURE 1, such synthetic cork may comprise a smooth cylindrical cork 10 having a shank 12 with a flat base portion 14 and a beveled or curved tip portion 16. With reference to PRIOR ART FIGURE 2, the flat base portion 14 is glued (note shaded adhesive area 17) to a cap portion 18 (e.g., plastic or wooden) to provide a synthetic cork with a cap useable by the user to remove and re-stopper the synthetic cork.

While such synthetic stoppers are useful for closing containers, only the bottom of the cork shank and the bottom of the hole in the cap touch and are held together by glue, creating a tensile glued structure. This configuration is problematic in the industry, as such configuration is known to separate during use. What is needed in the art is an improved glued synthetic cork.

Document EP0810159 A1 discloses the technical features of the preamble of claim 1.

The present invention comprises a composite synthetic cork, wherein the flat bottom of the synthetic cork shank includes radial contouring, such that a larger contact area is provided for glue contact to the synthetic cork. In exemplary embodiments, such radial contouring comprises a spoked design on the bottom of the cork shank.

In exemplary embodiments, a cap hole is utilized in conjunction with the synthetic cork having radial contouring, the cap hole having side walls that only permit liquid glue to flow up the side of the radial contouring. As noted, such configuration provides a larger contact area where the glue is holding the cork compared to traditional designs. This increases the holding force of the cork to the cap and combines the traditional tensile gluing force with an additional shear gluing force.

Referring now to the drawings, wherein like elements are numbered alike in the following FIGURES:

• PRIOR ART FIGURE 1 is side elevation view of a traditional synthetic cork;
• PRIOR ART FIGURE 2 is a top elevation view of a synthetic cork glued to a cap portion;
• FIGURE 3 is a side elevation view of an exemplary synthetic cork including a base portion having axial contours;
• FIGURE 4 is a bottom elevation view of the exemplary synthetic cork of FIGURE 3;
• FIGURE 5 is top elevation view of a first exemplary cap having a smooth gluing surface;
• FIGURE 6 is a top elevation view of a second exemplary cap having contoured side walls;
• FIGURE 7A is a side plan view of an exemplary cork in a pre-installed condition relative to an exemplary cap;
• FIGURE 7B is a side plan view of an exemplary cork in a post-installed condition relative to an exemplary cap;
• FIGURE 8A is a side plan view of an exemplary cork according to claim 1, in a pre-installed condition relative to an exemplary cap; and
• FIGURE 8B is a side plan view of an exemplary cork in a post-installed condition relative to an exemplary cap.

As was noted above, the present disclosure relates to an improved synthetic cork, wherein a flat bottom of the synthetic cork shank includes radial contouring, such that a larger contact area is provided for glue contact to the synthetic cork.

Referring now to FIGURE 3, an exemplary synthetic cork is illustrated generally at 20. The exemplary cork includes a shank portion 22, a base portion 24, and a beveled or curved tip portion 26. With reference to FIGURES 3 and 4, the base portion 24 has a flat bottom 28, and at least one radial contour 30, which contour provides increased contact area relative to traditional smooth base portion designs. In exemplary embodiments, as illustrated by FIGURES 3 and 4, such radial contouring 30 comprises a spoked design on the bottom of the cork shank.

FIGURES 5 and 6 illustrate exemplary caps 32 configured with a hole 34 sized to receive the base portion 24 of the synthetic cork. The exemplary cap 32 of FIGURE 5 shows a hole 34 having smooth sidewalls 36. The exemplary cap 32 of FIGURE 6 shows a hole 34 having contoured sidewalls 38.

FIGURES 7A and 7B illustrate an exemplary assembly of an exemplary cork and cap, wherein FIGURE 7A illustrates the cork and cap in a pre-installed configuration and FIGURE 7B illustrates the cork and cap in a post-installed configuration. As with FIGURE 4, the cork is illustrated having radial contouring 30. Also, as with FIGURE 5, the cap 32 is illustrated with a hole configured to accept the cork, the hole having smooth sidewalls 36.

FIGURES 8A and 8B illustrate another exemplary assembly of an exemplary cork and cap, wherein FIGURE 8A illustrates the cork and cap in a pre-installed configuration and FIGURE 8B illustrates the cork and cap in a post-installed configuration. As with FIGURE 4, the cork is illustrated having radial contouring 30. Also, as with FIGURE 5, the cap 32 is illustrated with a hole configured to accept the cork, the hole having smooth sidewalls 36. In this exemplary embodiment, at least a lower part 40 (near the base portion 24) of the shank portion 22 has an increased diameter relative to the cap hole 34. Thus, during installation, this lower part 40 creates a seal 42 that prevents excess adhesive from exiting the adhesive contact area 44 for the adhesive in the installed configuration (note that with regard to FIGURE 7B, depending on the amount of adhesive used, it may be possible to get some excess adhesive 46 outside the edges of the cap hole 34 without such seal 42 in addition to retaining adhesive within the nominal adhesive contact area 44). Such seal 42 not only serves to assist in adhesive retention in the nominal adhesive contact area 44 but also serves to provide a more aesthetically pleasing product.

In exemplary embodiments caps are utilized in conjunction with the exemplary synthetic cork 20 having radial contouring 30, the cap hole having side walls that only permit liquid glue to flow up the side of the radial contouring. As noted, such configuration provides a larger contact area where the glue is holding the cork compared to traditional designs. This increases the holding force of the cork to the cap and combines the traditional tensile gluing force with an additional shear gluing force. Tensile stress develops when forces acting perpendicular to the plane of a joint are distributed uniformly over the entire bonded area. Shear stress results when forces acting in the plane of the adhesive try to separate the adherents. The presently described caps advantageously combine both tensile and shear holding forces.

The synthetic cork component may comprise any acceptable synthetic cork material, and the cork may be formed by any convenient mechanism, including such materials and mechanisms as are-described in co-pending U.S. Patent Application Serial No. 11/640,999, filed December 19, 2006 and prior U.S. Provisional Application Serial No. 60/751,299 (In short, these applications describe methods of creating the random and irregular markings including molding the details directly into the surface of the stopper and extruding the synthetic material into a desired shape before passing it through forming cylinders or rollers that contain the negative of the desired surface texture, and which imprint the texture onto the material's exterior surface). The radial contouring 30 of the cork base portion 24 may be molded therein or shaped via forming devices.

It will be apparent to those skilled in the art that, while exemplary embodiments have been shown and described, various modifications and variations can be made to the synthetic cork and method of making disclosed herein without departing from the scope of the invention as defined by the appended claims. For example, recitations of projections and recesses on particular pieces are non-limiting, it being recognized that the arrangement may be reversed for a given piece. Accordingly, it is to be understood that the various embodiments have been described by way of illustration and not limitation.