Stress relieving indent formation for very thin thermoformed plastic films or foil/plastic laminates

Abstract

A pouch-style package formed of thin film comprising a front wall, a back wall, edge seals joining the front wall and back wall, and at least one bulge formation formed in a wall of the pouch-style package, having a stress-relieving indent formed in the wall in which said bulge formation is formed, the stress-relieving indent providing material to relieve excessive thinning or stress cracking at corners of the bulge formation.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 11/191,055, filed Jul. 28, 2005, and claims priority to U.S. Provisional Patent Application Ser. No. 60/591,623, filed Jul. 28, 2004, and U.S. Provisional Patent Application Ser. No. 60/598,064, filed Aug. 3, 2004, all of which are incorporated by reference herein.

BACKGROUND OF THE INVENTION

In the matter of pouch (sachet) style packages made of various very thin films, for example films of about 3 mils (0.003″) and less in thickness, in a variety of combinations such as coextruded multi-layer plastics, metal foil/thermoformable plastics, etc., it has been found that one or more bulges can be formed in at least one of the walls of the pouch (sachet) style containment package to increase the volumetric capacity of the pouch and/or to reduce the amount of material used to contain a specific volume, which reduces the cost significantly without much loss of barrier qualities. These bulges may be thermoformed for totally plastic walls, or, in the case of metal foil/plastic laminated combinations, where the foil is very thin, for example on the order of 0.0003″, air pressure forming has been the most efficient means. As a matter of fact, the pre-heating for thermoforming is detrimental for foil/plastic combinations since it weakens the bond between the foil and the plastic film which the foil needs for support, and the foil ruptures in numerous stress cracks when being pressure formed. It has been further observed that the rounded ball corners of such bulges tend to thin out to where they also show stress cracks.

SUMMARY OF THE INVENTION

The invention is directed to a system which will relieve excessive thinning and stress cracking of such rounded ball corners. The invention includes the formation of one or more stress-relieving formations in the bulge formation. In certain embodiments, the stress-relieving formation is an indent in the wall of the bulge formation. In other embodiments, the stress-relieving formation is a bulge or protrusion extending from the bulge formation. In one example, the stress-relieving formation may be a relatively shallow flat indented or protruded formation with semi-circular ends in the wall of the bulge formation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a pouch (sachet) with a bulge formation with a stress-relieving indent with semi-circular ends.

FIG. 2 shows another embodiment of a stress-relieving indent in the form of a channel with a semi-circular cross-section.

FIG. 3 shows another embodiment, with a plurality of stress-relieving indents.

FIG. 4 shows various shapes for stress-relieving indents, with FIG. 4A showing an alternative embodiment with the indent being a reverse indent or protrusion.

DETAILED DESCRIPTION OF THE DRAWINGS

A typical pouch-style package is normally rectangular. A bulge member 10 may be formed in one or more walls of the pouch. These bulges with or without indents may be utilized in ordinary rectangular pouches as currently available or with various patented easy opening pouches with a flap, or with a directional tear system.

The bulge member 10 may be parallel to the edge seals 20 with ball corners 12. In the embodiment of FIG. 1, an indent 30 with semi circular ends is formed in the wall of the pouch. The tiny wall of the indent relieves the stresses of forming the ball corners 12 by flattening out a little when the ball corners 12 are formed.

This indent system may further be utilized to reduce stresses and thinning in various other packaging and/or other uses which require formed thin wall systems.

It may be seen that the stress relieving indents may be of a variety of shapes. It may further be recognized that multiple indents of various or similar shapes may be applied to a single unit. The concept is that the indent yields additional material when the film/foil is being formed into a greater shape by flattening or deforming as the film is stretched, thereby yielding stress relief to the greater shape.

FIG. 2 shows another embodiment of a stress-relieving indent in the form of a channel with a semi-circular cross-section, as indicated by the line A-A′.

FIG. 3 shows another embodiment, with a plurality of stress-relieving indents, having a cross-section as indicated by the line B-B′.

FIG. 4 and FIG. 4A show various shapes for stress-relieving indents or protrusions. The indent at C-C′ in FIG. 4 is a semi-circular indent. FIG. 4A shows an alternative embodiment, in which the semi-circular indent in FIG. 4 is a reverse indent or protrusion. As shown in FIG. 4A, the indent at C″-C′″ in such an alternative embodiment is a reverse indent or protrusion having a similar shape as the indent at C-C′. The indent at D has a shape like a quarter-circle. The indent at E-E′ has an oblong shape. The indents at F-F′ and G-G′ are oblong in shape and crossed.

It will be appreciated that the stress-relieving indent or protrusion may take a variety of shapes within the scope of the claims.

Claims

1. A pouch-style package formed of thin film and containing a product to be dispensed, the pouch-style package formed by a process comprising the steps of:

providing a first thin film comprising laminated layers of metal foil and plastic;

providing a second thin film comprising laminated layers of metal foil and plastic;

forming a stress-relieving indent in at least the first thin film by air pressure forming;

sealing the first thin film to the second thin film at edge seals, the edge seals defining edges of the pouch-style package, wherein the pouch-style package comprises a first wall formed of the first thin film and a second wall formed of the second thin film, and wherein the first wall comprises the stress-relieving indent; and

forming a bulge formation in said first wall, wherein the step of forming a bulge formation includes the step of having the stress-relieving indent flatten or deform to facilitate the formation of the bulge formation in said first wall.

2. A pouch-style package as claimed in claim 1, wherein said bulge formation has corners and wherein the stress-relieving indent provides material to relieve excessive thinning or stress cracking at corners of the bulge formation.

3. A pouch-style package as claimed in claim 2, wherein the corners of the bulge formation are rounded ball corners.

4. A pouch-style package as claimed in claim 1, wherein the indent is a reverse indent so as to form a stress-relieving protrusion.

5. A pouch-style package as claimed in claim 1, wherein the indent is a relatively shallow flat indent with semi-circular ends.

6. A pouch-style package as claimed in claim 1, wherein the indent has a semi-circular cross-section.

7. A pouch-style package as claimed in claim 1, wherein the indent is oblong in shape.

8. A pouch-style package as claimed in claim 1, wherein the step of forming a bulge formation in said first wall takes place prior to sealing the first thin film to the second thin film.

9. A pouch-style package as claimed in claim 1, wherein the step of forming a bulge formation in said first wall takes place after sealing the first thin film to the second thin film.

10. A pouch-style package as claimed in claim 1, wherein the stress-relieving indent provides material to relieve excessive thinning or stress cracking in the bulge formation.

11. A process for forming a pouch-style package comprising the steps of:

providing a first thin film comprising laminated layers of metal foil and plastic;

providing a second thin film comprising laminated layers of metal foil and plastic;

forming a stress-relieving indent in at least the first thin film by air pressure forming;

sealing the first thin film to the second thin film at edge seals, the edge seals defining edges of the pouch-style package, wherein the pouch-style package comprises a first wall formed of the first thin film and a second wall formed of the second thin film, and wherein the first wall comprises the stress-relieving indent; and

forming a bulge formation in said first wall, wherein the step of forming a bulge formation includes the step of having the stress-relieving indent flatten or deform to facilitate the formation of the bulge formation in said first wall.

12. A process for forming a pouch-style package as claimed in claim 11, wherein said bulge formation has corners and wherein the stress-relieving indent provides material to relieve excessive thinning or stress cracking at corners of the bulge formation.

13. A process for forming a pouch-style package as claimed in claim 12, wherein the corners of the bulge formation are rounded ball corners.

14. A process for forming a pouch-style package as claimed in claim 11, wherein the indent is a reverse indent so as to form a stress-relieving protrusion.

15. A process for forming a pouch-style package as claimed in claim 11, wherein the indent is a relatively shallow flat indent with semi-circular ends.

16. A process for forming a pouch-style package as claimed in claim 11, wherein the indent has a semi-circular cross-section.

17. A process for forming a pouch-style package as claimed in claim 11, wherein the indent is oblong in shape.

18. A process for forming a pouch-style package as claimed in claim 11, wherein the step of forming a bulge formation in said first wall takes place prior to sealing the first thin film to the second thin film.

19. A process for forming a pouch-style package as claimed in claim 11, wherein the step of forming a bulge formation in said first wall takes place after sealing the first thin film to the second thin film.

20. A process for forming a pouch-style package as claimed in claim 11, wherein the stress-relieving indent provides material to relieve excessive thinning or stress cracking in the bulge formation.