Cushion Packs
A cushion pack including a corrugated fibreboard lattice within a flexible polymeric envelope which is vented to allow the air contained within the envelope to escape when the cushion pack is subjected to compression.
This invention relates to cushion packs, to methods of producing cushion packs and to use of cushion packs to protect packaged goods.
The name commonly given to the protection of goods or articles from shock, impact or vibration is “cushioning” and cushioning materials are often placed within what are known as cushion packs. In turn, cushion packs are placed upon or around different types of goods or articles, described herein as packaged goods, whilst being transported in transit packaging. In this context, packaged goods include fragile items such as wine bottles, glassware as well as fresh fruit and vegetables.
One of the main principles of cushioning is that a cushion pack mitigates shock, impact or vibration simply because the packaged goods sink or otherwise move into the cushion pack, decelerating progressively during the movement and therefore absorbing the kinetic energy of the packaged goods.
In order to understand the present invention, it is necessary to describe the fundamental principles governing what happens when a package is subject to shock, impact or vibration. The more rapidly that packaged goods are brought to rest, the greater the shock that they experience. It is also necessary to understand how packaged goods are damaged when they are subjected to shock, and how much shock packaged goods can withstand before they are damaged. The cause of damage may be simple to ascertain but becomes complicated as soon as the damage needs to be explained, quantified and methods of prevention proposed. We may say that a packaged article will break when some part of it is displaced beyond its “limit” as once displaced beyond this limit, the article will not, by this definition of limit, return to its initial position or to its original condition. The amount of cushioning required to prevent the packaged article from breaking as a result of the pack being subjected to shock is difficult to calculate theoretically, but it can be assessed and measured in practice by trial and error.
It is well known that the material known as corrugated fibreboard offers particularly good resistance to shock and hence corrugated fibreboard boxes are widely used for the protection of goods packed within them. Many different grades of corrugated fibreboard are in use, each one having its own performance parameters.
It is also well known that there is increasing pressure from legislation around the world to recycle or re-use waste packaging in order to reduce the impact upon the environment. Paper and fibreboard of all types can conveniently be recycled by means of re-pulping in water at different temperatures, but even so, the environment is affected as firstly, a certain amount of virgin fibres need to be added to the slurry, and secondly, the liquid effluent from the repulsing process needs to be treated before discharge into river courses, and thirdly, energy is required to transport the materials to the repulping plant and to process them, thereby releasing additional carbon dioxide into the atmosphere. It is therefore useful to find ways to re-use repulpable packaging materials as many times as possible before they are repulped.
The present invention has been made from a consideration of the foregoing and seeks to provide a cushion pack, a method of making such cushion pack and the use of such cushion pack to protect packaged goods, that overcomes or mitigates at least some of the problems of existing cushion packs.
Thus, according to one aspect of the invention, there is provided a cushion pack comprising a corrugated fibreboard lattice within a flexible polymeric envelope which is vented to allow the air contained within the envelope to escape when the cushion pack is subjected to compression.
The present invention takes into account the key parameters of shock or impact which are:
The distribution of shock throughout the packaged goods
The localisation of shock
The rate of absorption of shock by the packaged goods
The impact time, being defined as that time during which the packaged goods are moving within the package following shock or impact.
The impact time will vary according to the characteristics of the cushion pack being used. For example, packaged goods which are broken or otherwise damaged by a certain impact time may be undamaged by a shorter impact time. In the event of such a short impact time, damage is prevented due to the fragile part of the packaged goods not having time to become damaged. The impact time has been reduced as a result of dissipating the external forces throughout the package, thereby limiting the magnitude and duration of forces acting upon the packaged goods.
At the end of its useful life, all components of the cushion pack are preferably repulpable in hot or cold water.
Alternatively, the cushion pack may be disposed of by composting in which case, all components of the cushion pack are preferably compostable in compliance with the European Norm EN13432.
Preferably, the flexible polymeric envelope is vented by such means that no material is removed from the envelope during the formation of the vents. The vents in the polymeric envelope may be provided in a variety of ways, including interrupted sealing of one or more of the seals at the boundaries of the envelope.
The flexible polymeric envelope may have an area free of vents which is deliberately placed in direct contact with the packaged goods in order to avoid the ingress of contaminants from the packaged goods into the cushion pack.
The flexible polymeric envelope may, at least in part, for example its surface, be static dissipative in order to facilitate the packaging of sensitive electronic components.
The flexible polymeric envelope may, at least in part, provide a barrier to the ingress of contaminants such as oils, greases and hydrocarbon solvents.
Preferably, the polymeric envelope provides a contact surface that is non-abrasive to vulnerable packaged goods.
The flexible polymeric envelope may be woven from polymeric materials, thereby providing vents formed by the interstices within the weave.
According to another aspect of the invention there is provided a cushion pack comprising a corrugated fibreboard lattice within a flexible polymeric envelope which is vented to provide pneumatic cushioning by escape of gas within the envelope and/or physical cushioning by deformation of the fibreboard lattice when the cushion pack is subjected to compression.
The fibreboard lattice is preferably deformable resiliently so that the cushion pack can at least partially return to its original shape when the compression force is removed.
The polymeric envelope is preferably provided with one or more vents configured to allow gas within the envelope to escape in a controlled manner.
The polymeric envelope preferably exhibits good elasticity.
According to yet another aspect of the invention there is provided a method of malting a cushion pack comprising the steps of providing a lo corrugated fibreboard lattice, and enclosing the corrugated fibreboard lattice within a flexible polymeric envelope which is vented to allow air contained within the envelope to escape when the cushion pack is subjected to compression.
The cushion pack can be used to protect items in storage or transit either as a single cushion wrapped around the article to be protected, or as multiple layers of cushion. The cushion pack can be adapted so that when subsequently folded over itself and resealed, it can be used as a biodegradable (compostable) or water-soluble (repulpable) cushioned mailing bag, pockets or envelopes. Accordingly, such an embodiment allows the cushion pack to be used as a bag, pocket or envelope providing the benefits of a “padded” mailing bag, pocket or envelope incorporating the properties described in this application.
Preferably, the method employs recycled corrugated fibreboard to produce the corrugated fibreboard lattice. Accordingly, this invention provides a method of re-using waste corrugated fibreboard a number of times before it is repulped.
Corrugated fibreboard of any type may be employed to form the corrugated lattice by cutting the corrugated fibreboard into interconnected strips typically having a web width of between 2 and 25 mms. The best results are obtained by cutting the corrugated fibreboard in a similar manner to that used in the manufacture of expanded metal in which the corrugated fibreboard is cut in a pattern in which all the cuts are made in the machine direction but without any cut being long enough to separate the corrugated fibreboard into separate pieces. Each piece of corrugated fibreboard fed into the cutting process therefore remains a single interconnected piece after cutting, retaining approximately its initial weight. In this description of the present invention, we have chosen to describe the product resulting from this particular method of cutting and configuring corrugated fibreboard to produce interconnected strips as “a corrugated fibreboard lattice”. Once the corrugated fibreboard has been converted into such a lattice, it is preferably crinkled by which term we mean given a wave format in the machine direction of varying amplitude. This is done by adjusting the degree of compression of the corrugated fibreboard lattice in the machine direction.
The lattice is then separated into convenient web widths (transverse direction) and convenient lengths (machine direction) in order that it can then be packed into cushion packs by enclosing it within any flexible polymeric envelope capable of withstanding the required cushion to pressure.
It has been found that by making transverse cuts across the central portion of the corrugated fibreboard web before it is converted into a lattice, the resulting cushion pack exhibits greater three dimensional flexibility, i lending itself to be more easily “moulded” around the packaged item. The depth of the transverse cuts can vary up to a maximum of 50% of the thickness of the corrugated fibreboard and the length of the transverse cuts can extend across up to 80% of the web width, leaving approximately 100% of the web width uncut at either edge of the web. The transverse cuts may easily be made by means of rotating cutter blades or die cutting knives.
The cushion packs according to this invention may be made in a number of different ways and in a number of different places. Amongst the many options for the location of facilities to manufacture cushion packs, they may be made in a location where virgin corrugated fibreboard is produced, they may be made in a re-cycling centre where corrugated fibreboard is being collected and they may be made where the goods to be protected during transit are being packaged.
Polymeric films of any practical thickness may be used as long as they are flexible as this term is understood in the packaging industry. Thicknesses in the range 15-200 microns are usable, more especially preferred are film thicknesses in the range 25-100 microns. Any flexible film can be used and particularly useful are those films that have good elasticity, by which term we mean that the film will extend its dimensions under tension and will regain its original dimensions when the tension is removed. Inelastic films can be used provided that the contained ambient air can escape in a controlled manner by means of the vents without film rupture.
It is important that in each cushion pack, the flexible polymeric envelope contains a means of venting the contained ambient air following shock or impact to the transit pack within which one or more cushion packs are being used. The means of venting includes punctures, slits, and interrupted seals although these methods are by no means limiting. The means of venting is located in a certain pattern, in a sufficient number of places, in order to allow air to escape from the cushion pack in a controlled manner, by which term we mean that the rate of escape of the ambient air contained within the cushion pack is restricted in order that the packaged goods are optimally cushioned by the cushion pack following shock or impact to the transit package. It will be understood that the shape and weight of the packaged goods or articles will determine the size, number and arrangement of the means of venting the cushion pack.
The vents allow the cushion pack to dampen the acceleration of the packaged goods following shock or impact to the transit package and allow air to refill in whole or in part the cushion when the forces arising from shock or impact have been dissipated. In so doing, the cushion packs made according to this invention offer a degree of volume recovery or memory, which is particularly evident at high rates of crinkle of the corrugated fibreboard, The type, size and number of vents per unit area are selected in order that the cushion pack provides an optimal initial pneumatic cushioning effect which causes the packaged goods to decelerate optimally prior to utilising the additional cushioning effect provided by the corrugated fibreboard lattice. In his way the vents allow the air (or other gas contained within the envelope) to escape in a controlled manner and the corrugated fibreboard lattice deforms to achieve a desired cushioning effect when the pack is compressed.
Unexpectedly, it has been found that the cushion factor provided by cushion packs made according to this invention is higher than the sum of the cushion factors of empty punctured envelopes made from flexible polymeric substrates according to the methods described herein and the corrugated fibreboard lattice used in isolation. In other words, the two cushion effects are unexpectedly synergistic.
The release of dust or airborne fibre particles from the envelope of the cushion pack can be deleterious to certain classes of packaged goods, for example, electronic components or fresh produce for ingestion. This can be of particular concern where the corrugated fibreboard lattice has been made from post-consumer waste material, such as is collected in municipal waste recycling centres. In a preferred embodiment of the invention, the vents in the material of the envelope are puncture holes made by a sharp needle such that no material is removed from the flexible polymeric material. In puncturing the flexible polymeric material in this way, it ensures, as far as is possible, that no dust or airborne fibres from the corrugated fibreboard lattice, created during the cutting of the lattice or otherwise, pass through the puncture holes in the envelope (along with the ambient air contained within the envelope, thereby contaminating the packaged goods), when the cushion pack is compressed by an external shock or impact to the transit package.
The penetration of the envelope by contaminants such as oil, grease, or hydrocarbon materials can be deleterious to eventual repulping or composting of the cushion pack. Accordingly, where the packaged goods are protected from corrosion or for other reasons by oil, grease or hydrocarbon materials, the vents are preferably provided in an area of the envelope that is not in direct contact with the packaged goods. As an example which is by no means limiting, for the above reasons, the vents may be located in the side walls of the flexible polymeric envelope. By the term side walls, we include gusseted envelope constructions.
The vents are made in the flexible polymeric substrate used to form the envelope either during the manufacture of the substrate, typically by extrusion casting, solution casting or extrusion into a bubble, or in the conversion process by which the flexible polymeric substrate is by some means formed into an envelope around the corrugated fibreboard lattice to produce a cushion pack. Many of the machines used for fabricating packages from polymeric substrates may be used to practise this invention including, but not limited to, vertical or horizontal form-fill-seal machines, flow wrappers or L-sealers. Thus, the cushion pack may be sealed by whatever means on two sides, three sides or four sides according to the complexity of the design of the cushion pack and the degree of automation available for its manufacture.
Cellulose based materials are generally the most economical cushioning materials. However, some paper based products, including shredded paper and corrugated fibreboard, promote tarnishing and are therefore not suitable for use in packaging bare metal parts. This is because all cellulose based materials are hygroscopic and the risk of tarnishing bare metal parts at high humidity is thereby increased. In addition, many cellulose based materials, particularly corrugated fibreboard, are abrasive and can scuff and hence damage polished surfaces. Thus, the use of a corrugated fibreboard lattice enclosed within a flexible polymeric envelope to form cushion packs according to this invention provides economic and environmental benefits as well as enhanced cushioning performance.
In an embodiment of the invention, the flexible polymeric envelope is biodegradable so that the entire cushion bag is compostable after use in compliance with the European Norm EN13432.
In a further embodiment of the invention, the flexible polymeric envelope is water-soluble (which term is taken to include water-dispersible) so that the entire cushion bag is repulpable after use, the dissolution temperature of the water-soluble film being selected according to whether the repulping process takes place in cold water or hot water. In this embodiment, the water-soluble polymeric envelopes will assist in the repulping process as water-soluble polymeric materials such as, by way of example only, polyvinyl alcohol or carboxy methyl cellulose, are added during the repulping process as binders in the manufacture of recycled board or paper products.
The flexible polymeric envelope may be manufactured from films that are able to absorb moisture vapour until such time as they are in equilibrium with the moisture in the atmosphere to which they are exposed. As an example which is by no means limiting, the flexible polymeric envelope may be made from a water-soluble film containing polyvinyl alcohol. Such a film will contain a percentage of water as part of the plasticiser system. Typically this percentage will vary between 3% and 12% depending upon the particular application to which the polymeric envelope is destined. In any hermetically sealed space such as that which exists within a sealed package, the moisture content of the film will be in equilibrium with the moisture contained within the enclosed atmosphere. Should the temperature surrounding the package fall, as might be expected during transport or unheated storage, the relative humidity of the enclosed atmosphere will rise, possibly as far as the dew point when condensation would occur. It will be easily appreciated that this would be an undesirable situation as the packaged items may well experience damage from the condensation. The water-soluble envelope, due to its relatively large surface area, will absorb moisture from the enclosed atmosphere in seeking to maintain an equilibrium and thereby limit the rise in relative humidity and the risk of the dew point being reached with subsequent damage to the packaged items. It will be apparent that the use of water-soluble materials to form the flexible polymeric envelope can avoid the use of moisture absorbing products such as silica gel.
A similar moisture equilibrium will also establish itself within the flexible polymeric envelope, thereby reducing the risk of any moisture present in the corrugated lattice from contaminating or damaging the packaged items, or conversely, reducing the risk of the corrugated fibreboard lattice losing its structural properties due to ingress of moisture from the atmosphere surrounding the envelope.
The flexible polymeric envelope may also be manufactured from films that emit substances which affect, change or modify the atmosphere to which the envelope is exposed. The change in the atmosphere to which the envelope is exposed may be used to beneficial effect. As an example which is by no means limiting, the envelope may be made from a film containing a volatile corrosion inhibitor (VCI). The VCI is released from the envelope as a vapour into the atmosphere surrounding the envelope. Such a film is marketed under the trade mark Zerust®. Where the envelope is used to protect metallic items which are subject to tarnish, corrosion or rust in any hermetically sealed space such as that which exists within a sealed package, the release of VCI from the envelope will enable the packaged items to be both chemically and physically protected during storage or transit.
The invention will now be described in more detail by way of example only with reference to the accompanying drawing in which
The cushion pack 1 shown in the drawing comprises a flexible polymeric envelope 2 containing a corrugated fibreboard lattice 3. The cushion pack 1 as shown in
The envelope 2 is made of a polymeric material that may be soluble in hot or cold water to assist eventual re-pulping of the cushion pack 1. A suitable water-soluble material is a mixture of thermoplastic starch and polyvinyl alcohol having a thickness in the range of 15-200 microns.
The corrugated fibreboard lattice 3 is produced from a sheet of corrugated fibreboard by cutting in the manner described above to produce a series of slits 4 extending in the machine direction and defining a plurality of interconnected strips extending in the machine direction (cutting or longitudinal direction).
The cut sheet is then crinkled to produce an undulating wave-form shape giving the corrugated fibreboard lattice 3 a desired thickness and increased resilience in absorbing shock or impact and subsequently returning at least in part to its original shape. In
The envelope 2 is provided with vent openings 5. The vents 5 are formed preferably without removing material from the envelope by means of puncturing or perforating the envelope material or by means of interrupted seals or by any other suitable means.
The vent openings may be located such that they are not in direct contact with the packaged goods, for example in a side wall 6. In this way, any airborne contaminants carried by air exhausted from within the envelope to assist in cushioning shock or impact is directed away from the packaged goods. Also the risk of contamination of the corrugated fibreboard lattice 3 by oil, grease, hydrocarbon solvents or the like from the packaged goods is reduced.
The number, size and shape of the vent openings 5 is chosen so that air is exhausted from the envelope in a controlled manner to provide an initial pneumatic cushioning effect and the fibreboard lattice 3 is configured to compress resiliently to provide an additional cushioning effect before returning fully or partially to its original configuration. In this way, the cushion pack can absorb or dampen more than one impact.
It will be understood that the invention is not limited to the embodiment above-described. Various changes falling within the scope of the following claims will be apparent to those skilled in the art and the invention is deemed to include all such changes as well as any features equivalent to and/or performing the same function as any feature recited in the claims.
Claims
1. A cushion pack comprising a corrugated fibreboard lattice within a flexible polymeric envelope which is vented to allow the air contained within the envelope to escape when the cushion pack is subjected to compression.
2. A cushion pack according to claim 1 in which all components are compostable.
3. A cushion pack according to claim 1 in which all components are repulpable in hot or cold water.
4. A cushion pack according to claim 1 in which the flexible polymeric envelope is vented by such means that no material is removed from the envelope during the formation of the vents.
5. (canceled)
6. (canceled)
7. A cushion pack according to claim 1 wherein the vents are configured so that air contained within the envelope escapes in a controlled manner when the cushion pack is subjected to compression.
8. (canceled)
9. A cushion pack according to claim 1 in which an area of the polymeric envelope which, in use, is in direct contact with the packaged goods is free of vents.
10. A cushion pack according to claim 1 wherein at least the surface of the polymeric envelope is static dissipative.
11. (canceled)
12. (canceled)
13. A cushion pack according to claim 1 in which the material of the polymeric envelope absorbs moisture vapour from the atmosphere to which the envelope is exposed and/or from the materials within the envelope until an equilibrium is reached.
14. A cushion pack according to claim 13 in which the material of the polymeric envelope includes polyvinyl alcohol.
15. (canceled)
16. (canceled)
17. A cushion pack according to claim 1 in which the corrugated fibreboard lattice is configured to deform resiliently when the cushion pack is subjected to compression.
18. (canceled)
19. A cushion pack according to claim 1 in which the lattice is made from corrugated fibreboard that is partially cut in a transverse direction prior to being converted into the lattice in order to improve its three dimensional flexibility around a packaged item.
20. A cushion pack according to claim 1 in which the flexible polymeric envelope has elasticity.
21. (canceled)
22. A cushion pack according to claim 1 wherein the polymeric envelope is woven from polymeric materials, thereby providing vents formed by the interstices within the weave.
23. A cushion pack comprising a corrugated fibreboard lattice within a flexible polymeric envelope which is vented to provide pneumatic cushioning by escape of gas within the envelope and/or physical cushioning by deformation of the fibreboard lattice when the cushion pack is subjected to compression.
24. A cushion pack according to claim 23 wherein the fibreboard lattice is deformable resiliently so that the cushion pack can at least partially return to its original shape when the compression force is removed.
25. A cushion pack according to claim 23 wherein the polymeric envelope is provided with one or more vents configured to allow gas within the envelope to escape in a controlled manner.
26. (canceled)
27. A method of making a cushion pack comprising the steps of providing a corrugated fibreboard lattice, and enclosing the corrugated fibreboard lattice within a flexible polymeric envelope which is vented to allow air contained within the envelope to escape when the cushion pack is subjected to compression.
28. (canceled)
29. A method according to claim 27 wherein the fibreboard lattice is resiliently deformable to allow the cushion pack to return at least partially to its original shape when the compression is removed.
30. (canceled)
31. (canceled)
32. (canceled)
34. (canceled)
35. (canceled)
36. A method according to claim 27 wherein the polymeric envelope is vented to direct air exhausted from within the envelope away from packaged goods protected by the pack.
37. (canceled)
38. A cushion pack according to claim 1 wherein the polymeric envelope comprises a polymeric film having a thickness in the range 15-200 microns.
Type: Application
Filed: Nov 24, 2006
Publication Date: Nov 13, 2008
Inventors: David Brian Edwards (Hertfordshire), Bruce Michael Drew (Essex), William John McCarthy (Dorset)
Application Number: 12/094,045
International Classification: B65D 81/05 (20060101);
