AU765395B2

AU765395B2 - Improvements in packaging, particularly wool bags

Info

Publication number: AU765395B2
Application number: AU19520/00A
Authority: AU
Inventors: Dennis Sullivan
Original assignee: Individual
Current assignee: Primmer Patrick John
Priority date: 1999-03-23
Filing date: 2000-02-28
Publication date: 2003-09-18
Anticipated expiration: 2020-02-28
Also published as: AU1952000A

Description

Regulation 3.2 Revised 2/98

AUSTRALIA

Patents Act, 1990

ORIGINAL

COMPLETE SPECIFICATION TO BE COMPLETED BY THE APPLICAF NAME OF APPLICANT: ACTUAL INVENTOR: ADDRESS FOR SERVICE: INVENTION TITLE: Patrick John Primmer Dennis Sullivan Peter Maxwell Associates Level 6 Pitt Street SYDNEY NSW 2000 IMPROVEMENTS IN PACKAGING, PARTICULARLY WOOL BAGS r n 4 The following statement is a full description of this invention including the best method of performing it known to me:m:\docs\20001142\038543.doc IP Australia Documents were received on: JUL 23 Batch No: 2 Field of the Invention The present invention relates to improvements in packaging materials, particularly for wool bags.

Background of the Invention Wool bags are containers which are used to carry wool, the filled bags being referred to as wool bales. It is an important requirement for wool bales that they contain wool in a tightly packed form whilst retaining a substantially regular shape which allows the bales to be stacked in accordance with industry requirements. Wool bags are currently made from either woven high density polyethylene or woven nylon.

However, woven wool bags have some substantial disadvantages.

Wool is sampled by a process known as core sampling, in which process a hole or holes is/are cut through the wool bag and a sample of wool removed.

In this process the high density polyethylene tends to defibrillate and small e bits of fibre contaminate the wool. Any fibrous polyethylene or nylon that contaminates the wool within the bale is difficult to remove during the subsequent processing of the wool and can lead to contamination of the final eeee fabric produced from the wool. Polyethylene is a "non-substantive" fibre which means that it takes dye at a different rate from wool fibre. Any contamination of wool with polyethylene can spoil fabric made from the contaminated wool. Nylon is "substantive" which means it takes dye at substantially the same rate as the wool so the effect of contamination of the wool with nylon is much less damaging than contamination with polyethylene. However, a woven nylon sack is approximately four times the cost of a woven high density polyethylene bag and consequently results in added expense as compared with using a polyethylene bag.

Wool bales must also be able to withstand the forces and temperatures involved in the formation of "dumped" or compressed wool bales. Wool bales are compressed in order to reduce their volume so that they take up less space when being transported, or stored. During the dumping process, bales of wool are generally compressed 3::1 by volume, usually three bales being compressed into the volume occupied by one bale. In the dumping process, three bales are placed end to end between two large metal plates and the bales are compressed. The compression of the bales creates a considerable amount of friction and heat, typically resulting in temperatures of 1500C to 1800. The wool bag material has to be able to withstand those temperatures and also has to allow the egress of air from the bales, i.e. the bag has to be able to breath during the dumping process.

Attempts have been made to make wool bags from plastic films. These attempts have failed for a number of reasons. The polymers used to form the plastic films either have too low a melting point so they cannot withstand the heat generated in the dumping process, and/or the films do not breath and consequently prevent air from leaving the wool bale. This can lead to the explosion of the wool bags.

The present invention seeks to provide a wool bag which is cheaper to make than a woven nylon bag but yet is compressible during the dumping process, which is also able to withstand the heat generated during the dumping process and which is preferably recyclable.

Summary of the Invention In a first broad aspect, the present invention provides a material for °:forming a wool bag including:a first film of multi-layer material, said first film comprising: a first layer comprised of a polymer having a melting point above about 1800C; a second layer of a polymer having a low temperature melting point; and linking means for linking the first and second layers together; a second film of multi-layer material including a third layer of a polymer having a low temperature melting point, and a carrier 25 layer; and a mesh or textile layer disposed between the first film and the second film, the first and second films being either both bonded to the 11/07/03 mesh or textile layer or bonded to each other through the mesh or textile layer, wherein a number of holes are provided extending through the material, the arrangement being such that channels are formed between the mesh or textile layer and the first and second films so as to allow the passage of air between the first and second films in the plane of the material.

The present invention also provides a wool bag constructed from the material of the present invention with the first layer disposed on the exterior of the bag.

The polymer having a melting point above about 18000 is most preferably nylon, and may be either nylon 6 or nylon 66 or nylon 666 or blends of these.

If nylon is used, the first layer may be as little as 10 to 20 microns thick, which is a tiny fraction of the nylon required for woven nylon mesh bags. As nylon is an expensive polymer, this results in substantial cost savings.

The layers of polymer having a low temperature melting point may be SurlynT" or single site metalocene polymers.

The mesh or textile layer may be a mesh of the type which is typically used for making net bags for fruit such as oranges or the like, such as Netlon Such meshes are typically formed by forming a grid of members comprising strands of the polymers and then welding them together with the application of heat which results in the formation of enlarged nodules where the members of the grid intersect. Such a grid has a substantial advantage 25 when used in the material of the present invention in that the nodules prevent the first and second films from laminating together at or near the nodule and assist in the passage of air in the plane of the material. However, the mesh 11/07/03 could be formed from other materials, such as polypropylene, polyethylene or nylon.

The use of a mesh has other advantages in that handling technology for wool bales is unsophisticated; typically grab hooks are used to pick up and hoist the bales; and the provision of a mesh helps prevent the material from tearing. However, a woven fabric textile could also be used in place of a mesh.

An additional advantage of the present invention is that the material provides contact clarity. In other words, it is possible to look through a wool bag and see any wool in contact or close to the material so that buyers of wool bales get a better chance to see the product which they may wish to purchase.

The use of two films and the inner mesh or textile layer bonded together, provides a material which is surprisingly strong, and is resistant to tear propagation. Although the material is particularly useful for forming wool bags, it may have other uses where similar properties are required.

Brief Description of the Drawings 1°:The invention will now be described by way of example only and with reference to the accompanying drawings in which: S•Figure 1 is a schematic plan view of a sheet of material for forming a .oo.oi wool bag embodying the present invention; Figure 2 is a schematic view along lines I-I shown in Figure 1; and Figure 3 is a schematic view along lines I1-Ill shown in Figure 1.

Detailed Description of a Preferred Embodiment Referring to the drawings, the Figures show a sheet of material 10 for forming a wool bag comprising a mesh 12 sandwiched between two multi-layer 25 films. The mesh is formed from Netlon

T

which comprises a grid of parallel members 12a, 12b intersecting at right angles with enlarged nodules 14 formed where the members intersect and are welded together.

11/07/03 With reference to Figures 2 and 3, the first multi-layer film, generally indicated at 20, comprises an outer or first layer 22 of nylon, an outer or second layer 26 of Surlyn" and an inner tie layer 24 formed from a material which can be bonded both to the layer 22 of nylon and to the layer 26 of Surlyn The second multi-layer film 30 comprises a third layer 32 also made from Surlyn T m bonded to a carrier layer 34.

The layers 26 and 32 of Surlyn can be heat activated to seal together at 850C and they bond together in the square spaces between the squares of the mesh 12. However, because of the presence of the mesh 12, channels 36 are formed where there is a gap between the mesh 12 and the first and second films 20, 30 and this allows air to travel in the plane of the material along those channels. The material 10 also has a number of holes, not shown, pierced therethrough, including some holes which pass into the channels 36. The material is made up into a bag with the first layer 22 of nylon on the outside to form a wool bale. During the compression process, when three such bags are typically compressed into one, the outer surfaces of the wool bags are pressed flush between two steel plates which are closed together to compress the wool bales. Using the material of the wool bag of the et• eeeooe t 11/07/03 I I_ present invention, excess air can escape in the plane of the material parallel to the plane of the compression plates by travelling along the channels 36.

This is particularly advantageous since air trying to travel at right angles through the material would be trapped by the steel plates and would not be able to escape, and the bag could explode.

Although the present invention describes a wool bag formed from material comprising a three layer multi-layer film and a two layer multi-layer film, variations in the number of layers of the multi-layer films would be possible depending on the desired properties of the bag.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the *1 invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

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Claims

1. A material for forming a wool bag including:- a first film of multi-layer material, said first film comprising: a first layer comprised of a polymer having a melting point above about 180C; a second layer of a polymer having a low temperature melting point; and linking means for linking the first and second layers together; a second film of multi-layer material including a third layer of a polymer having a low temperature melting point, and a carrier; and a mesh or textile layer disposed between the first film and the second film, the first and second films being either both bonded to the mesh or textile layer or bonded to each other through the mesh or textile layer, wherein a number of holes are provided extending through the material, the arrangement being such that channels are formed between the mesh or o textile layer and the first and second films so as to allow the passage of air between the first and second films in the plane of the material.

2. The material of claim 1, wherein the polymer having a melting point above about 1800C is nylon.

3. The material of claim 2, wherein the nylon is selected from the group consisting of nylon 6, nylon 66, nylon 666 and blends of these nylons.

4. The material of claim 2 or claim 3, wherein the thickness of the first layer •is 10 to 20 microns. 11/07/03 LIIIII1__--XI._L_-LC i 8 The material of any one of the preceding claims, wherein the second and third layers of polymer having a low melting point are Surlyn T or single site metalocene polymers.

6. The material of any one of the preceding claims, wherein the mesh or textile layer is a mesh of the type made by forming a grid of members comprising strands of the polymers and then welding them together with the application of heat, and includes enlarged nodules where the members of the grid intersect.

7. The material of claim 6, wherein the mesh is formed from materials selected from the group consisting of polypropylene, polyethylene and nylon.

8. The material of any one of claims 2 to 5 wherein the mesh or textile layer is a woven fabric. A wool bag constructed from the material of any one of claims 1 to 8, wherein the first layer is disposed on the exterior of the bag. .ooo.) A material substantially as hereinbefore described with reference to the accompanying drawings.

11. A wool bag substantially as hereinbefore described with reference to the accompanying drawings. Dated this 11 day of July 2003 Patrick John Primmer Patent Attorneys for the Applicant PETER MAXWELL ASSOCIATES 11/07/03 _i _ilt ~I i-iil-^li liliYi-.L~)i-Liiii-~=-I_- L_