NZ280021A - Snap fit reclose device with a base which tapers from the rib or channel to the longitudinal edge thereof - Google Patents

Description

Patents Form # 5 28 0021 v. * ^ /* //■' ^' o V •* \ SlJSEP igg6 NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION AFTER PROVISIONAL # : 280021 DATED : 14 September 1995 TITLE : Improvements in or relating to a reclose device We, Minigrip Flexible Packaging Limited Address: 27 Ross Reid Place, East Tamaki, Auckland, New Zealand Nationality: New Zealand do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: PF05.JWP FEE CODE 1050 This invention relates to reclose elements for bags, and/or reclose elements, and/or bags formed thereby.

Reclose elements or zippers are increasingly being used in conjunction with plastic bags. These are frequently made by attaching the zippers onto films of plastics 5 material so that either a pre-made bag is formed or in some instances the zippers are attached during the bag making process. A number of problems occur in the manufacture and use of such bags in the area where the cross seal or end seal intersects and is sealed to the side weld.

For example, with fast moving consumer goods there is a demand for a quality 10 appearance. That is to say the aesthetics are important. Fast moving consumer goods applications also frequently require a hermetic seal without risk of leakage principally out of the sealed bag. Because of the high volumes necessary with such fast moving consumer goods high processing speeds are required to meet the pricing demands.

Traditionally the zippers or reclose elements have been of two basic shapes. One of 15 these provides the zipper rib or zipper channel on a flange and the flange is heat sealed to the bag (or to a tape or strip which is attached to the bag) usually in at least two places. This provides a substantially rigid and stable connection which does not in the hands of the user exhibit excessive tendencies to roll and also gives a good feel of mass and weight.

An alternative approach is to provide the reclose element, ie the channel or rib on an elongated narrower strip often known as a string. This string is then heat sealed to a 9007ICS1.996/CW/iv 28 0 0 21 tape or to the bag often by providing a number of small ribs on the rear face which melt to provide the adherence. In terms of customer and consumer user friendliness the flange construction provides a better feel and stability as well as reducing rolling or distortion. However, the string approach has less material therein and therefore less 5 material has to be dispersed or sealed around particularly at the intersection between the reclose elements and the side welds.

It is therefore an object of the present invention to provide a reclose element and or a method of forming a reclose element and or a bag which will go at least some way towards meeting the foregoing considerations in a simple yet effective manner or 10 which will at least provide the public with a useful choice.

Accordingly in one aspect the invention consists in a reclose device comprising a pair of elongated elements, one having an elongated rib and the other an elongated channel, the channel or the rib being a snap fit one into the other in use, said rib being mounted on a base and the channel being mounted on a base, at least one base being 15 relatively wide and thin.

Preferably each elongated element is formed of a plastics material.

Preferably the base tapers from the rib or channel to the longitudinal edges of the elongated element.

Preferably the base is 12 to 25mm in width. 9007ICS1.996/CW/iv 28002.1 Preferably the base is substantially 130 microns in thickness in the area adjacent the channel or rib.

Preferably the base is substantially 90 microns thick at the longitudinal edges.

Preferably one or each of the bases can have a backing membrane thereon said 5 backing membrane having a lower sealing temperature than the remainder of the elongated element.

Preferably the thickness of the backing membrane is such that the overall thickness of the construction is as above described.

In a further aspect the invention consists in a method of forming a reclose device 10 comprising the steps of forming a base using blown film techniques to form a sheet of plastics material of substantially 50 to 130 microns in thickness, forming said material into strips and extruding a rib or channel element onto a strip so that in use strips of material may be adhered to a further substrate to form reclose elements for bags.

Preferably said sheet of plastics material is of substantially 50 to 100 microns in 15 thickness.

Preferably said base members are multi-layered.

In a still further aspect the invention consists in a reclose device when manufactured by a method according to either of the preceding paragraphs. 9007ICS1.996/CW/iv 280021 In a still further aspect the invention consists in a bag having thereon a reclose device formed according to any one of the preceding paragraphs.

To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest 5 themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

One preferred form of the invention will now be described with reference to the accompanying drawings in which, Figure 1 is a diagrammatic transverse cross section of a reclose device according to one preferred form of the invention, Figure 2 is a diagrammatic side elevation of a bag including the reclose element of figure 1, and Figure 3 is a diagrammatic transverse cross sectional view of a reclose element 15 according to a further aspect of the invention.

Referring to figure 1 a reclose device 1 is provided which is formed of two elements 2 and 3. The element 2 has a base member 4 and a longitudinal elongated rib 5 having a bulbous distal portion 6. The elongated element 3 is substantially similar except that 9007ICS1.996/CW/iv - 6 ■ 280021 the rib 5 is replaced by the narrow mouthed channel 7. The rib 5 is a "snap fit" into the channel 7.

The overall width of the reclose element may be any desired width but in particular is substantially 12 to 25mm in width. This is wider than the usual base width of 8 to 5 12mm used with reclose tapes. In the construction of figure 1 the base elements 2 and 3 also taper from the central portion to the longitudinal edges such as edges 10 and 11 of the element 2. The element 2 may have a thickness in the vicinity of the rib 5 of, for example, about 130 microns tapering to a thickness of about 90 microns in the area of the longitudinal edges 10 and 11. If desired included in this thickness may be a 10 membrane 12 which may have a thickness of about 10 microns, for example, of a material which has a lower heat sealing temperature than the material of the reclose elements 2 and 3. For example, the membrane may be a low density polythene having a tack temperature, for example, about 50°C lower than the tack temperature of the members 2 and 3. The members 2 and 3 are then sealed into the mouth of a bag 15, 15 for example, in any known manner. For example either by direct sealing or sealing onto a tape which is subsequently attached to the bag. Side welds 16 are formed in the bag and the side welds run over the areas 17 at the ends of the reclose element 1. It is a particular advantage of the construction shown in figure 1 that the relatively wide flanges of narrow construction allow the material to be readily displaced to form an 20 aesthetic side weld in the region of the junction between the side weld and the reclose elements which is able to be manufactured at high speed whilst yet retaining a high success rate in terms of the leak proof nature and hermetic sealing qualities of the bag. 9007ICS1.996/CW/iv 28 0021 A further embodiment of the invention is shown in figure 3. In figure 3 a reclose element 20 is provided which provides a pair of flanges 21 and 22 which may be of substantially 50 microns to 130 microns in thickness preferably 50 to 100 microns in thickness or of known or usual widths, or if desired can be substantially as shown in 5 figure 1. The flange parts 21 and 22 are formed by blown film techniques which allows fine control of the thickness of the flange elements and also allows multi-layered constructions to be formed in a simple manner. Onto the base elements 21 and 22 are extruded the bulbous longitudinal rib 23 and channel member 24 as required. Again with this construction the flanges are adhered to a bag or a tape which 10 will itself be adhered to a tape and used substantially in the known manner. The advantage of this construction is that multi-layers can be obtained whilst retaining fine control of thickness which leads to consistency in the gauge of the materials.

The provisions of thin wide flanges allows the feel of a flanged construction but also allows the material to be readily dispersed in the areas where the reclose elements 15 intersects the side welds. 9 00*7 ICS 1.996/CW/iv 280021

Claims (10)

WHAT WE CLAIM IS:

1. A reclose device comprising a pair of elongated elements, one having an elongated rib and the other an elongated channel, the channel or the rib being a snap fit one into the other in use, said rib being mounted on a base and the channel being mounted on a base, at least one base being relatively wide and thin and tapers from the rib or channel to the longitudinal edges of the elongated element.

2. A reclose device as claimed in claim 1 wherein each elongated element is formed of a plastics material.

3. A reclose device as claimed in either claim 1 or claim 2 wherein both the bases taper from the associated rib or channel to their longitudinal edges.

4. A reclose element as claimed in any one of the preceding claims wherein the base is 12 to 25mm in width.

5. A reclose element as claimed in either claim 3 or claim 4 when dependent on claim 3 wherein the base is substantially 130 microns in thickness in the area adjacent the channel or rib.

6. A reclose element as claimed in claim 3 or either one of claims 4 and 5 when dependent on claim 3 wherein the base is substantially 90 microns thick at the longitudinal edges. i— intellectual property office of n.z. 9007LCS1.998/CW/ct 2 9 SEP 1998 RECEIVED -9- 280021

7. A reclose element as claimed in any one of the preceding claims wherein one or each of the bases can have a backing membrane thereon said backing membrane having a lower sealing temperature than the remainder of the elongated clement,

8. A rcclose element as claimcd in claim 7 wherein the thickness of the backing membrane is such that the overall thickness of the construction is substantially as herein described with reference to the accompanying drawings.

9. A bag having thereon a reclose device formed according to any one of the claims 1-8.

10. A reclose element substantially as herein described with reference to Figures 1 and 2 of the accompanying drawings. rxwvuiliwjrd AVI, MINIGRIP FLEXIBLE PACKAGING LIMITED 9007LC31.99B/CW/ct